123456 1 - 50 of 285
rss atomLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
  • Public defence: 2019-10-04 10:00 V2, Stockholm
    Solis Valdivia, Jerry Luis
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Process Technology.
    Conversion processes for biofuel production2019Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Despite the global positive impacts of soybean-, maize- and sugarcane-based (first-generation) liquid biofuels, several drawbacks pertaining to increased use of agricultural land, causing deforestation in some countries and extensive practice of fertilizers have been observed. As a result, developing advanced (second- and third-generation) liquid biofuels have been identified as better alternatives and are considered to be of great importance in the future. These alternative biofuels will help to meet the energy demand by transition to ameliorate and fulfil the energy demand, especially in the transport sector.The actual energy demand for fossil fuels in Bolivia is unsustainable due to its continuous increase. Bolivia has its own fossil fuel resources, but these still fall short of demand, forcing the government to budget for yearly fuel imports. This situation has prompted attempts to achieve energy independence through the production of biofuels. However, it is important that Bolivian energy independence endeavours include a sustainable vision. Bolivia has great potential for local first- and second-generation liquid biofuel production. However, the intensification of liquid biofuel production should focus on second- and third-generation biofuel production to minimize direct and indirect undesired impacts.This thesis considers the development of suitable technology and procedures to produce second-generation liquid biofuels, which can be divided into biodiesel and ethanol production. The proposed biodiesel production includes the development of heterogeneous catalysts that enable the production of biodiesel from edible and non-edible oils (i.e. rapeseed, babassu, and Ricinus oils). These heterogeneous catalysts are based on gel-based mayenite and alumina supports with the co-precipitation of metal oxides of calcium, lithium, magnesium and tin. The synthesized catalysts were characterized using, N2 physisorption, X-ray powder diffraction, scanning electron microscopy, and thermogravimetric analysis (TGA). The experimental design and optimum results indicate that heterogeneous biodiesel production is feasible, being able to produce biodiesel yields ranging from 85% to 100%. Ethanol production was studied using the residues of Schinus molle seeds after the essential oil extraction process, which is available in excess in Bolivia. The biomass was characterized to elucidate its properties using high-performance liquid chromatography and TGA. The biomass was pre-treated with chemical, physical, andVIenzymatic hydrolysis to increase the fermentation yield. To obtain the highest ethanol production, two native yeast strains were isolated and characterized. By using native yeast strains, a high content of ethanol per gram of biomass was achieved. The proposed implementation of the fermentation process could result in a significant global warming potential reduction. The implementation of heterogeneous catalysts to produce biodiesel and residual lignocellulosic biomass to produce ethanol represent a great potential to supply the Bolivian fuel demand. High biodiesel and ethanol yields from second-generation feedstocks are feasible and could help reduce pollution levels and import dependency.

  • Pallikarakis, Christos
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Ion irradiation effects on Si nanocrystal properties2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • Leenders, Benji
    KTH, School of Engineering Sciences (SCI), Physics.
    Assesment of the isotopic inventory built-up in ISOL targets operated with 100-MeV protons and the migration of the volatile species in the ISOL system2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • Jain, Saumey
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Detection of Biomolecules by an Extended Gate Field Effect Transistor2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • Engström, Helena
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Network Analysis of Calcium Activity2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • Bulancea Lindvall, Oscar
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Quantum Methods for Sequence Alignment and Metagenomics2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • Public defence: 2019-09-20 09:00 T2, Huddinge
    Marlevi, David
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems, Medical Imaging.
    Non-invasive imaging for improved cardiovascular diagnostics: Shear wave elastography, relative pressure estimation, and tomographic reconstruction2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Throughout the last century, medical imaging has come to revolutionise the way we diagnose disease, and is today an indispensable part of virtually any clinical practice. In cardiovascular care imaging is extensively utilised, and the development of novel techniques promises refined diagnostic abilities: ultrasound elastography allows for constitutive tissue assessment, 4D flow magnetic resonance imaging (MRI) enables full-field flow mapping, and micro-Computed Tomography (CT) permits high-resolution imaging at pre-clinical level. However, following the complex nature of cardiovascular disease, refined methods are still very much needed to accurately utilise these techniques and to effectively isolate disease developments.

    The aim of this thesis has been to develop such methods for refined cardiovascular image diagnostics. In total eight studies conducted over three separate focus areas have been included: four on vascular shear wave elastography (SWE), three on non-invasive cardiovascular relative pressure estimations, and one on tomographic reconstruction for pre-clinical imaging.

    In Study I-IV, the accuracy and feasibility of vascular SWE was evaluated, with particular focus on refined carotid plaque characterisation. With confined arterial or plaque tissue restricting acoustic wave propagation, analysis of group and phase velocity was performed with SWE output validated against reference mechanical testing and imaging. The results indicate that geometrical confinement has a significant impact on SWE accuracy, however that a combined group and phase velocity approach can be utilised to identify vulnerable carotid plaque lesions in-vivo.

    In Study V-VII, a non-invasive method for the interrogation of relative pressure from imaged cardiovascular flow was developed. Using the concept of virtual work-energy, the method was applied to accurately assess relative pressures throughout complex, turbulence-inducing, branching vasculatures. The method was also applied on a dilated cardiomyopathy cohort, indicating arterial hemodynamic changes in cardiac disease.

    Lastly, in Study VIII a method for multigrid image reconstruction of tomographic data was developed, utilising domain splitting and operator masking to accurately reconstruct high-resolution regions-of-interests at a fraction of the computational cost of conventional full-resolution methods.

    Together, the eight studies have incorporated a range of different imaging modalities, developed methods for both constitutive and hemodynamic cardiovascular assessment, and utilised refined pre-clinical imaging, all with the same purpose: to refine current state cardiovascular imaging and to improve our ability to non-invasively assess cardiovascular disease. With promising results reached, the studies lay the foundation for continued clinical investigations, advancing the presented methods and maturing their usage for an improved future cardiovascular care.

  • Public defence: 2019-09-19 13:00 Kollegiesalen, Stockholm
    Prästings, Anders
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Managing uncertainties in geotechnical parameters: From the perspective of Eurocode 72019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Geotechnical engineering is strongly associated with large uncertainties. Geotechnical site investigations are made only at discrete points and most of a soil volume is never tested. A major issue is therefore how to cost effectively reduce geotechnical uncertainties with respect to structural performance. Managing the geotechnical uncertainties is thus an important aspect of the design process. Guidance on this subject is given in the European design code for geotechnical design, Eurocode 7 (EN 1997), which advocates the use of the partial-factor method, with the added possibility to use the observational method if the uncertainties are large and difficult to assess.This thesis aims to highlight, develop and improve methods to assess the quality and value of geotechnical site investigations through reliability-based design. The thesis also discusses the limitations of the deterministic partial-factor method, according to its EN 1997 definition, and how to better harmonise this design methodology with the risk-based approach of reliability-based design. The main research contributions are: (1) a presented case study showing the importance of and potential gains with a robust framework for statistical evaluation of geotechnical parameters, (2) the discussion on the limitations of the partial-factor method in EN 1997, and (3) the discussion on how to harmonise the EN 1997 definition of the partial-factor method with the risk-based approach of reliability-based design.

  • Björnberg, Inez
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Unsbo, Hanna
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Biokolsproduktion från släke: En studie om lämpligheten att producera biokol från gotländska alger och vattenlevande växter2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The Baltic sea has multiple environmental problems, such as over-fertilization and high concentration of certain heavy metals, caused by human activity. Yearly, beach-cast is washed up on the shores of Gotland and this biomass is today not utilised to a considerable extent. This report aims to assess the suitability of producing biochar from the left over beach-cast. During this study a visit to Gotland, interviews and a literature study has been completed, which has laid the groundwork for calculations of energy and material balances regarding algae-based biochar production.

    The beach-cast contains approximately 0.9 mg cadmium per kg and consists of 80 % water, in which common species found are eelgrass and furcellaria, among others. For the calculations of energy- and material balances, two different pretreatment alternatives were used before the pyrolysis. Alternative A simply uses preheating and alternative B consist of a composting step before a finishing preheating session. The most energy efficient was alternative B as the power consumption per kilo produced biochar was 14,5 MJ/kg compared to 29,8 MJ/kg.

    The use of beach-cast for manufacturing biochar has benefits as well as disadvantages. Beach-cast is an unexploited resource that could be used for biochar production, but on the other hand the process is demanding energy-wise due to the high amount of water in the biomass. The utilisation of cadmium rich biochar is also problematic due to the risk of the heavy metal leaching. Based on the results it is therefore complicated to estimate the suitability of a beach-cast based biochar.

  • Johansson, Niklas
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Karlsson, Saga
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Water reuse in peri-urban areas: A case study of Kibondemaji, Dar es Salaam, Tanzania2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    An increasing number of countries worldwide is becoming water-stressed, sub-Saharan Africa being one of the most recurrent regions within this discourse. Tanzania, one of the countries in the region, is no exception: large population growth has increased pressure on its precious water resources. The largest city, Dar es Salaam, has a poorly maintained and dimensioned water supply and wastewater system. However, as this system expands and more people are given access to the water network, the water consumption of the city is expected to increase. This is problematic for the whole city; however, peri-urban areas suffer the most from its consequences, e.g. periodical water shortages. This report seeks to investigate the potential for saving water in one of these peri-urban areas, Kibondemaji, by looking at fields of application and techniques for reuse of wastewater from showers. This is done via a literature review and interviews in the field in order to analyse and compare the different systems – reuse for tapwater, irrigation and toilet flushing. The interviews showed that there is wide acceptance within the community for water reuse for toilet flushing but not for tap water or irrigation. Reuse for toilet flushing also requires less treatment than other fields of application, thus being the most promising technique for implementation in Kibondemaji.

  • Nilsson, Viktor
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Serck, Ola
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    A comparative study of manually and remote-controlled valves in Dar es Salaam: Efficiency of remote-controlled water valves in water supply systems2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Water is an essential resource for basic human survival, but today several cities and people lack access to both reliable and clean water. Dar es Salaam in Tanzania is undergoing a rapid population growth and need to improve their current water delivery system in order to provide water to the city’s inhabitants. This report’s objective is to examine if Dar es Salaam Water and Sewerage Authority (DAWASA) manual water valve operation is improved with the usage of remote-controlled valves instead. The remote-controlled system will consequently be evaluated and compared against the manually controlled valves. In order to obtain necessary data for this study interviews and field trips were conducted at DAWASA as well as at the local market at Kariakoo. Additionally, information has also been gathered from the collaboration partners at College of Information and Communication Technologies (CoICT).

    The results provided information that a remote-controlled system could, in the measured reference area of 52 km of water pipes, save up to 900 U.S dollar monthly and 46 m3 of water daily for DAWASA. These savings would consequently contribute to an increase in resources which leads to further improvements to the current water distribution system. Because, today’s system is in need of a development in order to sufficiently provide potable water to the city. The remote-controlled system could also help to reduce the spread of waterborne diseases, destruction of roads and create a more reliable source of water since the water valves would be regulated more efficiently. A remote-controlled system would however need a sufficient amount of funding in order to be installed, but is both simpler to install and a more feasible solution compared to other alternatives. For these reasons, the designed system is concluded to be a more effective, sustainable and economical feasible solution for handling and managing the outdated valves.

  • Cavendish, Maia
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Urban and Regional Studies.
    Public Art and Residual Urban Spaces: The Case for Informal Public Art in Stockholm2019Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    While Stockholm has made significant investments in formal public art throughout the inner city and suburbs, the city has a lack of informal public art. Defined as a feature or work produced by a person who considers themselves to be an artist or craftsperson, located in a place accessible to and used by the public, public art can be either formal or informal. Informal public art generally has no formal process, with flexibility on the temporal nature of the work, materials and subject. This allows the artwork to inhabit spaces which are overlooked or underinvested in by formal public art commissioning bodies, and not have to follow formal public art requirements which are part of the broken “public art machine”. (Phillips, 1988). Much of Stockholm’s urban environment is considered beautiful, has heritage value and/ or is protected. But Stockholm also hosts many spaces in between – spaces that hold the city together, including infrastructure, bridges, alleys, and the places under and between them. These spaces can be labelled as a city’s residual spaces (Villagomez, 2010), and are where informal public art can be utilised to make these spaces into places. This study outlines the importance of and background to public art in the context of Stockholm. A survey of Stockholm’s residents, visitors and potential future visitors established how they feel about public art in the city, as well as in residual urban spaces, and to what extent it assists with establishing a place connection. This was accompanied by onsite interventions and observational analysis which challenged the way residual urban spaces are being used in Stockholm, and developed a case for how informal public art can be incorporated in the city’s residual urban spaces.

  • Katycheva, Anna
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    From Brownfields to Green Infrastructure: A resilience thinking approach to brownfield transformation2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Brownfields have the potential to be transformed to offer green infrastructure to cities and bottom up environmental stewardship approaches can be a creative and dynamic way of providing much needed ecosystem services to the urban environment. The following study explores how the transformation of a contaminated site to a community garden in Stockholm can contribute to providing ecosystem services and improving general resilience. Through aqualitative method including literature review, interviews and observations; the results showed elements contributing to resilience including an increase in the diversity of the urban landscape, the creation of a space for social connections, and a gateway to sharing knowledge and creating polycentricity in natural resource management.

  • Stjernquist Desatnik, Marie
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Energy Access for the Most Vulnerable Groups: A Study on the Long-Term Effects of Energy Access in a Refugee Camp Context with Inclusion of the Host Community2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The UN 2030 Agenda for Sustainable Development outlines 17 goals to end poverty and ensure the right to development for everyone. Previous research has found that 2/3 of the goals partly depend their success upon whether SDG 7 Ensure access to sustainable, affordable and modern energy for all is achieved or not. Given that the Agenda targets everyone it cannot be achieved without reaching the most vulnerable groups, among these groups are migrants, refugees and those internally displaced. Low- and middle-income countries host 84% of this group. Almost 30% of refugees live in managed camp settings and it has been estimated that 80% of these have minimal or no access to electricity. For cooking needs a majority depend on traditional cooking with firewood and charcoal. In many cases this spurs tensions and at times conflict with the local host community, -who often also heavily depend on this resource. On the national level energy is often seen as part of the long-term development planning and as refugee camps and humanitarian setting are recognized as temporary by the host country this creates a vacuum. However, the reality is that 2/3 of all refugees are in protracted refugee situations and the average lifespan of a camp is 17 years. This thesis studied the links between energy and the nexus of environment, social stability and economy in a refugee camp context, and outlined how different energy systems could impact the situations for both groups and also for the relationship between these groups. This was done using the Long-range Energy Alternative Planning systems (LEAP) and by creating a Multi Criteria Analysis template. The case study of Kakuma camp in Turkana County in the North of Kenya was used. The results showed that there are positive and negative aspects related to all energy systems studied here (for household energy access both for electricity and cooking). A refugee camp is a highly complex setting, operating both under the authority of local actors and of international humanitarian actors. For electricity access, Solar Home Systems was found to be a good choice due to the fast deployment time and the low level of infrastructure needed. For already existing households PV Hybrid mini-grids are to be recommended. For cooking options, it was found that for Turkana county, rather than just focusing on GHG emissions it is vital to mitigate deforestation seeing the county’s vulnerability to land-use change. However, changing from firewood and charcoal would affect the livelihood of the host community who depends on the income deriving from the charcoal business. This highlights some of the complexity of the study and the importance of knowing the local context before carrying out energy interventions in a refugee camp and surrounding area. The author’s conclusion is that this methodology could be implemented on any camp setting seeing that modern and clean energy access poses many benefits to people across the world, whether in an urban, rural or refugee camp setting. The thesis found that the main barriers identified for electricity projects of scale are the current funding structure of humanitarian organizations and national government’s attitude towards the camp.

  • Persson, Jennifer
    KTH, School of Industrial Engineering and Management (ITM).
    Stakeholder & Developer Communication Powered by Product Owners2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The purpose of this study is to investigate the challenges and opportunities in the communication between software developers and their stakeholders, as well as the impact that the product owners have on the communication. The research was conducted using a case study approach, and data was mainly collected through observations andinterviews with product owners and software developers at the case company Kry. The findings show that the challenges in communication are the technical language of software developers, difficulty for stakeholders to understand the software development process and difficulty for developers to understand the underlying context of a feature request. The opportunities in their communication are that the developers can better understand the reasons of a request and thus feel more engaged in the product and more satisfied towards the company; Good communication can cut development time and cost. The product owner is shown to be almost irreplaceable due to the large impact that they have. They become translators between the developers and stakeholders, enabling them to communicate better. Furthermore, they are the main point of contact for the stakeholders, thus allowing the developers to focus more on doing development work. However, this might sometimes result in that the developers get involved too late in the process, making changes costly when they discover something faulty. As a conclusion, the communication between stakeholders and developers powered by product owners greatly enhance the possibility to build good, maintainable software and lead to a more sustainable work environment for all involved.

  • Engström, Pontus
    KTH, School of Industrial Engineering and Management (ITM).
    Exploring the non-technical challenges: A case study of identity and access management projects2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The implementation of an Identity and Access Management (IAM) solution is a complex process to manage, consuming multiple years and involves organizational changes. In its nature, several challenges tend to appear to different stakeholders involved in the process. However, prior research has mainly addressed the technical components of an IAM-solution, hence the technical challenges that emerge during development and implementation. Therefore, the non-technical challenges of the IAM-project work and the challenges that constitute the client implementation are understudied. The purpose of this thesis is to visualize the challenges that emerge when an IAM-solution is implemented. In addition, the challenges when organizational changes occur. The empirical data is conducted through a series of semi-structured interviews with individuals in the IAM line of business. In addition, secondary data is gathered through the review of papers and reports in Information Systems (IS) and Information Technology (IT) projects and outsourcing projects, as well from a non-academical organization with in-depth knowledge of IAM implementations. A qualitative case study of IAM implementations was conducted to investigate the studied complex phenomenon. The findings display the challenges of Insight, Communication, and Endurance (ICE), which tend to be obstacles for all stakeholders involved. Additionally, the organizational changes describe three further challenges of Anchoring, Communication, and Vision (ACV). These challenges mainly appear in client changes, which IAM implementations initiate. The thesis display connections and incoherent with prior research on IS/IT-projects and IAM-projects. In addition, newly uncovered aspects that contribute to research areas are highlighted. The thesis is summarized with some implications and possibilities for future research.

  • Axelsson, Alice
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Flexible high chair for home environments: Development of a first prototype solution that facilitate storage and transportation2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    When small children eat, they usually sit in a high chair to reach the same table level as the adults. There are many different kinds of high chairs on the market with different functionalities, such as high chairs that grows with the child and high chairs that are attached to ordinary chairs. Some households have more than one alternative, just because their ordinary high chair isn’t easy to transport. Furthermore, due to compact living situations, it can be advantageously having the possibility of easily store it away when the high chair isn’t in use.

    Therefore, the purpose with this project was to develop a first prototype proposal of a flexible high chair, that easily can be stored and transported, but still fit within home environments. The project presented in this report is a master thesis project conducted during spring 2019 within the master program Industrial Design Engineering at the Royal Institute of technology, in conjunction with Svensk Konstruktionstjänst and their client Twistshake.

    The project followed an iterative product development process. It included research to obtain deeper understandings of the users, analysis of the results and determination of project direction, concept generation and concept selection. A mock-up and prototype were made to test ideas. Based on this, the final result of the project was developed. In the project, two of UN’s 17 global sustainable development goals were taken into consideration: number 3, good health and well-being and number 12, responsible consumption and production.

    The result of the project is a first prototype solution of a flexible high chair. It is a high chair that grow with the child from around 6 months to 4 years old. It is developed to facilitate the child’s development and by that offer long user time, which also favour the environment. When not in use, the high chair can easily be folded into a flat package for storage or transportation.

    As the project was limited to 20 full time weeks, further work needs to be done before reaching a real product. The first prototype and suggestions of further work has been discussed.

  • Löfgren, Kim
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Hannula Virving, Lisa
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Avstämningsmetod för installatörer kopplat till slutkostnadsprognos2019Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    This master thesis has mainly been built on interviews with interested parties at Arcona and the installer, Nymans Elektriska, since it was decided to limit the study only to the project Glömstaskolan. The aim of the study is that Arcona should be able to report a more accurate final cost forecast to the client regarding the installer and to simplify the reconciliation for both the construction company and the installer. The background is based on the fact that installers do not calculate components and activities such as other building production, which makes it difficult to reconcile if an activity has been carried out in accordance with budget. Both parties agree that it is working hours that need to be checked, as this is where the difficulty of control lies. To be able to check real hours, knowledge of the planned number of hours is needed. The time schedule is an important tool in the project and should be included in reconciliation. Arcona and Nymans Elektriska are recommended to use existing control documents with certain appendixes for the measuring progress.

  • Sandberg, Marcus
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Andersson Svorono, Gabriel
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Undersökning av energideklarationer: Uppfyller de sitt syfte att bidra till en effektiv energianvändning i byggnader?2019Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    In 2002, a directive from EU stated that the countries should start keeping better track of how buildings consume energy. From this directive a law was introduced that implied that energy declarations now were to be established. The main purpose of energy declarations was for them to contribute to efficient energy use and a healthy indoor environment. This was to be achieved by giving a general view of the building’s energy status, as well as basis for investments in making the building more energy efficient. This master’s dissertation examines if energy declarations fulfill their purpose of contributing to an efficient energy use. After questioning of real estate company’s personnel and examining energy declarations, they proved to be considered adequate in showing a building’s general energy consumption. However, the action proposals are often considered too simplistic. Instead, many companies base their actions in order to make the building more efficient on their own personnel, their thorough investigation and detailed analysis of a building’s energy consumption. This detailed analysis gives a clearer picture of where energy can be saved and in what way actions should be made in order to be most efficient. The purpose of energy declarations is therefore only partially fulfilled.

  • Eriksson, Petter
    et al.
    KTH, School of Engineering Sciences (SCI).
    Dalbom, Daniel
    KTH, School of Engineering Sciences (SCI).
    Simulering av system med flera agenter genom användande av djup förstärkande inlärning2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Reinforcement Learning has been getting a lot of attention in recent years, mostly through its use in teaching computers to play video and board games. In this report it is investigated how well algorithms from this area can be used to solve a multi-agent problem. The multi-agent problem to be solved is teaching robots how to transport items through a warehouse without colliding. A Q-learning based algorithm is proposed to solve the problem. Because of the scalability issues a DQN based algorithm is also proposed. The scalability issues arise in systems of higher complexity, in systems characterized by multiple agents or a large environment. It is shown that Qlearning fails to learn a good strategy in a reasonable time. Simulations are made to illustrate the behaviour of the proposed algorithms. The results of the simulations suggest that DQN performs considerably better compared to Q-learning when the dimensions of the problem are larger.

  • Public defence: 2019-09-16 09:00 F3, Stockholm
    del Aguila Pla, Pol
    KTH, School of Electrical Engineering and Computer Science (EECS), Information Science and Engineering.
    Inverse problems in signal processing: Functional optimization, parameter estimation and machine learning2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Inverse problems arise in any scientific endeavor. Indeed, it is seldom the case that our senses or basic instruments, i.e., the data, provide the answer we seek. It is only by using our understanding of how the world has generated the data, i.e., a model, that we can hope to infer what the data imply. Solving an inverse problem is, simply put, using a model to retrieve the information we seek from the data.

    In signal processing, systems are engineered to generate, process, or transmit signals, i.e., indexed data, in order to achieve some goal. The goal of a specific system could be to use an observed signal and its model to solve an inverse problem. However, the goal could also be to generate a signal so that it reveals a parameter to investigation by inverse problems. Inverse problems and signal processing overlap substantially, and rely on the same set of concepts and tools. This thesis lies at the intersection between them, and presents results in modeling, optimization, statistics, machine learning, biomedical imaging and automatic control.

    The novel scientific content of this thesis is contained in its seven composing publications, which are reproduced in Part II. In five of these, which are mostly motivated by a biomedical imaging application, a set of related optimization and machine learning approaches to source localization under diffusion and convolutional coding models are presented. These are included in Publications A, B, E, F and G, which also include contributions to the modeling and simulation of a specific family of image-based immunoassays. Publication C presents the analysis of a system for clock synchronization between two nodes connected by a channel, which is a problem of utmost relevance in automatic control. The system exploits a specific node design to generate a signal that enables the estimation of the synchronization parameters. In the analysis, substantial contributions to the identifiability of sawtooth signal models under different conditions are made. Finally, Publication D brings to light and proves results that have been largely overlooked by the signal processing community and characterize the information that quantized linear models contain about their location and scale parameters.

  • del Aguila Pla, Pol
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Information Science and Engineering.
    Jaldén, Joakim
    KTH, School of Electrical Engineering and Computer Science (EECS), Information Science and Engineering.
    Inferences from quantized data - Likelihood logconcavityManuscript (preprint) (Other academic)
    Abstract [en]

    In this paper, we present to the signal processing community the most general likelihood logconcavity statement for quantized data to date, together with its proof, which has never been published. In particular, we show how Prékopa’s theorem can be used to show that the likelihood for quantized linear models is jointly logconcave with respect to both its location and scale parameter in a broad range of cases. In order to show this result and explain the limitations of the proof technique, we study sets generated by combinations of points with positive semi-definite matrices whose sum is the identity.

  • Ruffa, Giorgio
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Towards unification of organ labeling in radiation therapy using a machine learning approach based on 3D geometries2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In radiation therapy, it is important to control the radiation dose absorbed by Organs at Risk (OARs). The OARs are represented as 3D volumes delineated by medical experts, typically using computed tomography images of the patient. The OARs are identified using user-provided text labels, which, due to a lack of enforcement of existing naming standards, are subject to a great level of heterogeneity. This condition negatively impacts the development of procedures that require vast amounts of standardized data, like organ segmentation algorithms and inter-institutional clinical studies. Previous work showed that supervised learning using deep-learning classifiers could be used to predict OARs labels. The input of this model was composed of 2D contours of the OARs, while the output was a standardized label. In this work, we expanded this approach by qualitatively comparing the performance of different machine learning algorithms trained on a clinical data set of anonymized prostate cancer patients from the Iridium Kankernetwerk clinic (Belgium). The data set was partitioned in a semi-automatic fashion using a divide-and-conquer-like approach and various 2D and 3D encodings of the OARs geometries were tested. Moreover, we implemented a reject class mechanism to assess if the inference probability yielded by the model could be used as a measure of confidence. The underlining goal was to restrict human intervention to rejected cases while allowing for a reliable and automatic standardization of the remaining ones. Our results show that a random forest model trained on simple 3D-based manually engineered features can achieve the twofold goal of high classification performance and reliable inferences. In contrast, 3D convolutional neural networks, while achieving similar classification results, produced wrong, but confident, predictions that could not be effectively rejected. We conclude that the random forest approach represents a promising solution for automatic OAR labels unification, and future works should investigate its applications on more diversified data sets.

  • Elers, Andreas
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Continual imitation learning: Enhancing safe data set aggregation with elastic weight consolidation2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The field of machine learning currently draws massive attention due to ad- vancements and successful applications announced in the last few years. One of these applications is self-driving vehicles. A machine learning model can learn to drive through behavior cloning. Behavior cloning uses an expert’s behavioral traces as training data. However, the model’s steering predictions influence the succeeding input to the model and thus the model’s input data will vary depending on earlier predictions. Eventually the vehicle may de- viate from the expert’s behavioral traces and fail due to encountering data it has not been trained on. This is the problem of sequential predictions. DAG- GER and its improvement SafeDAGGER are algorithms that enable training models in the sequential prediction domain. Both algorithms iteratively col- lect new data, aggregate new and old data and retrain models on all data to avoid catastrophically forgetting previous knowledge. The aggregation of data leads to problems with increasing model training times, memory requirements and requires that previous data is maintained forever. This thesis’s purpose is investigate whether or not SafeDAGGER can be improved with continual learning to create a more scalable and flexible algorithm. This thesis presents an improved algorithm called EWC-SD that uses the continual learning algo- rithm EWC to protect a model’s previous knowledge and thereby only train on new data. Training only on new data allows EWC-SD to have lower training times, memory requirements and avoid storing old data forever compared to the original SafeDAGGER. The different algorithms are evaluated in the con- text of self-driving vehicles on three tracks in the VBS3 simulator. The results show EWC-SD when trained on new data only does not reach the performance of SafeDAGGER. Adding a rehearsal buffer containing only 23 training exam- ples to EWC-SD allows it to outperform SafeDAGGER by reaching the same performance in half as many iterations. The conclusion is that EWC-SD with rehearsal solves the problems of increasing model training times, memory re- quirements and requiring access to all previous data imposed by data aggre- gation.

  • del Aguila Pla, Pol
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Information Science and Engineering.
    Pellaco, Lissy
    KTH, School of Electrical Engineering and Computer Science (EECS), Information Science and Engineering.
    Dwivedi, Satyam
    Ericsson Research.
    Händel, Peter
    KTH, School of Electrical Engineering and Computer Science (EECS), Information Science and Engineering.
    Jaldén, Joakim
    KTH, School of Electrical Engineering and Computer Science (EECS), Information Science and Engineering.
    Clock synchronization over networks - Identifiability of the sawtooth modelManuscript (preprint) (Other academic)
    Abstract [en]

    In this paper, we analyze the two-node joint clocksynchronization and ranging problem. We focus on the case of nodes that employ time-to-digital converters to determine the range between them precisely. This specific design leads to a sawtooth model for the captured signal, which has not been studied in detail before from an estimation theory standpoint. In the study of this model, we recover the basic conclusion of a well-known article by Freris, Graham, and Kumar in clock synchronization. Additionally, we discover a surprising identifiability result on the sawtooth signal model: noise improves the theoretical condition of the estimation of the phase and offset parameters. To complete our study, we provide performance references for joint clock synchronization and ranging. In particular, we present the Cramér-Rao lower bounds that correspond to a linearization of our model, as well as a simulation study on the practical performance of basic estimation strategies under realistic parameters. With these performance references, we enable further research in estimation strategies using the sawtooth model and pave the path towards industrial use.

  • Satei, Mehdi
    KTH, School of Electrical Engineering and Computer Science (EECS).
    OTT Video-Oriented Mobile Applications Development Using Cross-Platform UI Frameworks2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Google and Apple together are ruling the mobile phone industry with their operating systems, Android and iOS. Any mobile application willing to reach the vast majority of end-users, need to be run on both platforms. The issue, however, arises when considering that fact that developing an application for each platform requires different knowledge and code base. Cross-platform frameworks are emerged to overcome the mentioned issue by providing the possibility to develop a mobile application which works on multiple platforms with potentially a single code base.To investigate the capabilities of cross-platform frameworks, three frameworks were chosen to be compared; React Native backed by Facebook, Xamarin owned by Microsoft, and Flutter developed by Google. The chosen frameworks have been compared in the context of OTT Videooriented mobile applications. As a reference application OTT Flow, an OTT Video application developed by Accedo, has been used.The findings in this thesis shows that Xamarin is not a good choice for the purpose of this thesis since no advantages were witnessed in most of the criteria. React Native and Flutter, on the other hand, offer promising features which suit developing OTT applications. When considering the video-specific functionalities, however, React Native stood out slightly better. In fact, even though React Native is possibly the best choice among the mentioned frameworks for developing OTT Video-oriented mobile applications, the cross-platform frameworks are not mature enough in terms of video-specific functionalities support yet.

  • Landmark, David
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    The WELL Building StandardA Study of Bengt Dahlgren's office in Stockholm2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Throughout our lives, we spend approximately 80–90% of our time indoors, and the environment which wereside in is a key factor determining our comfort and well-being. A favorable indoor environment can enhance our quality of life whereas a less than favorable environment may have the opposite effect. A key ambition of several Green Building Certifications is the desire to reduce a building’s environmental impact and energy consumption, and, in addition, the ambition to provide a satisfying indoor environment.The WELL Building Standard (WELL) is an up and coming green building certification explicitly embracing comfort, health and well-being in the built environment. The standard covers seven over-arching topics forwhich the indoor environment is evaluated by; Air, Water, Nourishment, Light, Fitness, Comfort, andMind. Compared to well-established Green Building Certifications like LEED, BREEAM and Miljöbyggnad, the WELL standard is newly introduced on the Swedish market with few current applications.

    The purpose of this report is to apply WELL for Bengt Dahlgren’s office in Stockholm and provide resultsdemonstrating to what extent the office satisfies the certification. The report will also provide recommendedmeasures so as to reach a desired WELL certification grade. Furthermore, the compliance between WELL and the Swedish Green Building Certification Miljöbyggnad will be studied. The study has been carried out byreviewing the relevant policy, property and equipment documents; conducting technical measurements; andinspecting the conditions of the office area and its surroundings. Correspondence with stakeholders and actorsknowledgeable of the current state of the office have been a constant element throughout the project. 

    The results show that Bengt Dahlgren’s office currently do not fulfill the required preconditions to be eligiblefor a WELL certification. However, if those preconditions were to be addressed, a completed certificationwould result in a grade corresponding to Silver. By implementing the recommendations provided by the authorit should also be possible to reach the higher certification grade Gold. The study furthermore concludes that WELL and Miljöbyggnad only demonstrate limited overlap. By evaluating Bengt Dahlgren’s office in Stockholm, this report strives to give insight for how a Swedish office facility comply with the WELL certification. The work should also give light to new perspectives and applications regarding health, comfortand well-being which may not be included in traditional Green Building Certifications. The compliance for WELL with Swedish regulations, standards and norms have been treated in this report, however, the topic can be suggested as an area for future work, as there is room for an explicit study concerning this.

  • Das, Sandipan
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Silicon photonics based MEMS tunable polarization rotator for optical communications2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    There has been a huge surge in data traffic all over the world due to the rise of streamingmedia services and connected devices. The current demand in data traffic has alreadypushed the optical fiber in the internet architecture to the network edges and the trend isto push it as close as possible, to the CPU. Silicon photonics addresses this challenge byenabling miniaturized optical devices that use light to move huge amounts of data at veryhigh speeds with extremely low power. To further improve the data transmission capacity,one can make use of different polarizations of light. However, to take advantage ofdifferent polarizations, devices with on-chip polarization rotation capability are required.This is achieved by a tunable polarization rotator. Moreover, full control of polarizationrotation can also be utilized to realize a new class of components in integrated photonicsincluding polarization mode modulators, multiplexers, filters, as well as switches foradvanced optical signal processing, coherent communications, and sensing.This thesis introduces a novel tunable polarization rotator that uses microelectromechanicalsystems (MEMS) as its actuation principle. When voltage is applied to a MEMStunable silicon cantilever, a mechanical movement occurs, which in turn affects theoptical mode shape travelling through a waveguide, as a result of which the polarizationis rotated. In this work, a MEMS tunable polarization rotator is designed, fabricated,and characterized with a polarization extinction ratio of 10 dB, which works in 1530nm -1570nm wavelength spectrum. In addition to the MEMS tunable polarization rotator,in this thesis, a free standing polarization beam splitter of length 1.4 μm, the shortestreported to-date to our knowledge, was designed, fabricated, and characterized. Thetunable polarization rotator and beam splitter developed in this thesis have the potentialto increase the bandwidth and flexibility of current optical communication networks, andfind further applications in polarization diversity schemes for sensing.

  • Ahlin, Björn T. I.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Nitrogen Removal in a Vacuum Tank Degasser: An Investigation on the Nitrogen Removal Performance2019Independent thesis Advanced level (degree of Master (Two Years)), 300 HE creditsStudent thesis
    Abstract [en]

    The impending change of processes at SSAB Oxelösund due to the HYBRIT project, where the blast furnace and LD converter are to be replaced with an EAF will have a significant impact on the manufacturing of steel in Oxelösund. One issue that will arise is the nitrogen content in the steel. Sources claim that the nitrogen content in steel from an EAF route is substantially larger, 60-70 ppm, than in steel from a blast furnace and LD converter route, which have a nitrogen content of around 25 ppm. Therefore, the nitrogen removal capabilities of SSAB Oxelösund’s vacuum tank degasser were to be examined. Industrial trials were performed where the amount of slag during vacuum treatment was lowered. The intention was that half the amount of slag removed prior to vacuum treatment and later completely slag free. This was performed in an attempt to increase the effective reaction area, where nitrogen removal occurs. Due to some practical problems with the steel mill, the industrial trial were unfortunately cut short. Consequently, only trials with half the amount of slag were performed and compared to existing process data for standard praxis. Also, nitrogen removal calculations based on the industrial data were performed. A parameter representing the overall reaction rate, which is dependent on effective reaction area was obtained, validated and subsequently applied to a future case scenario. The results indicate that the reduction in slag amount does have the desired effect, increasing the said area and increasing the rate of nitrogen removal. However, the sample size is not nearly sufficient enough to determine this definitively. The conclusions reached were that the facility does have the possibility to decrease the increased nitrogen content down to reasonable levels, around 20-30 ppm. Albeit, an increase in vacuum treatment time is probably required. Another conclusion was that surface active elements, such as oxygen and sulphur greatly reduce the nitrogen removal. Therefore, efforts should be taken to remove these elements prior to vacuum treatment. In addition, it was established that the effective reaction area is of great importance for a successful nitrogen removal. Therefore, actions to maximise this area should be taken. Finally, it was stated that further research is necessary in order to fully understand nitrogen contamination prevention- and removal techniques

  • Henning, Martin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Tollkuci, Endi
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Energy simulation model for commercial buildings Beridarebanan 4, 11 and 77, with ice thermal storage2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    District cooling companies enforce a large penalty based on peak demands, which current cooling methods do not address properly. Building developers are exploring alternatives methods to reduce the said peak demands. The use of Ice Thermal Storage is an nontraditional method within the Scandinavian countries, but has shown to be a method to peak shave as well as load shifting in other regions of the worlds. The goal of the thesis was to "investigate the potential of ice thermal storage for cooling demand and peak shaving for Beridarebanan 4, 11, 77". The energy simulation was accomplished using the building performance simulator software IES VE. As inputs to the simulation, building data from the renovation project and corresponding weather data were used. The resulting simulation model was validated against renovated data with differences of 3,3% and 41,9% for the heating and cooling loads, respectively. The large discrepancy within cooling was determined to be weighted heavily by cooling strategy implemented within the building. When similar cooling strategies were implemented results were consistent with one another. This validation was investigated on a building, zone, and room level to look for consistency. The resulting simulated heating and cooling demands from IES VE were input into a then created ice thermal storage controller within MS Excel. In all, with the stable electrical and district cooling prices, a payback of 12 years was calculated for a 4,5 MWh, 6 hour storage ITS system. Results also show that for a 6 hour storage capacity,the controller exceeded the 1 000 kW price tier 4 hours out of the entire year, making it an ideal storage size. Current Swedish Electrical Market incentivize peak shaving rather than energy saving, accounting for nearly 80% of the yearly savings. The margin for earning more for the energy savings has negative consequences for potentially exceeding the 1 000 kW cooling threshold.

  • Perju, Dragos-Stefan
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Applying Memoization as an Approximate Computing Method for Transiently Powered Systems2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Internet of Things (IoT) is becoming a more and more prevailing technology, as it not only makes the routine of our life easier, but it also helps industry and enteprise become more efficient. The high potential of IoT can also help support our own population on Earth, through precision agriculture, smart transportation, smart city and so on. It is therefore important that IoT is made scalable in a sustainable manner, in order to secure our own future as well.The current work is concerning transiently powered systems (TPS), which are embedded systems that use energy harvesting as their only power source. In their basic form, TPS suffer frequent reboots due to unreliable availability of energy from the environment. Initially, the throughput of such systems are therefore lower than their battery-enabled counterparts. To improve this, TPS involve checkpointing of RAM and processor state to non-volatile memory, as to keep computation progress saved throughout power loss intervals.The aim of this project is to lower the number of checkpoints necessary during an application run on a TPS in the generic case, by using approximate computing. The energy need of TPS is lowered using approximations, meaning more results are coming through when the system is working between power loss periods. For this study, the memoization technique is implemented in the form of a hash table. The Kalman filter is taken as the testing application of choice, to run on the Microchip SAM-L11 embedded platform.The memoization technique manages to yield an improvement for the Kalman application considered, versus the initial baseline version of the program. A user is allowed to ”balance” between more energy savings but more inaccurate results or the opposite, by adjusting a ”quality knob” variable epsilon ϵ.For example, for an epsilon ϵ = 0.7, the improvement is of 32% fewer checkpoints needed than for the baseline version, with the output deviating by 42% on average and 71% at its maximum point.The proof of concept has been made, being that approximate computing can indeed improve the throughput of TPS and make them more feasiable. It is pointed out however that only one single application type was tested, with a certain input trace. The hash table method implemented can behave differently depending on what application and/or data it is working with. It is therefore suggested that a pre-analysis of the specific dataset and application can be done at design time, in order to check feasiability of applying approximations for the certain case considered.

  • Zhao, Yu
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Channel Reconstruction for High-Rank User Equipment2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In a 5 Generation massive Multiple Input Multiple Output radio network, the Channel State Information is playing a central role in the algorithm design and system evaluation. However, Acquisition of Channel State Information consumes system resources (e.g. time, frequency) which in turn decrease the link utilization, i.e. fewer resources left for actual data transmission. This problem is more apparent in a scenario when User Equipment terminals have multi-antennas and it would be beneficial to obtain Channel State Information between Base Station and different User Equipment antennas e.g. for purpose of high rank (number of streams) transmission towards this User Equipment. Typically, in current industrial implementations, in order to not waste system resources, Channel State Information is obtained for only one of the User Equipment antennas which then limits the downlink transmission rank to 1. Hence, we purpose a method based on Deep learning technique. In this paper, multi-layer perception and convolutional neural network are implemented. Data are generated by MATLAB simulator using the parameters provided by Huawei Technologies Co., Ltd. Finally, the model proposed by this project provides the best performance compared to the baseline algorithms.

  • Brus, Alexander
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Validation of energy efficiency requirements for machine tools and industrial washing machines2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Production equipment accounts for a large portion of the energy use from industry. But so far there has been no standardized way of requiring energy efficiency when purchasing a new machine. Scania is therefore implementing energy efficiency requirements in their purchasing process for production equipment. As a part of this, there needs to be a way of validating that the requirements have been fulfilled. This study aims to find how requirements on energy efficiency in production equipment can be validated in a user friendly and time efficient way. Firstly, the energy efficiency requirements set by Scania and by regulations are mapped. Then these requirements are clearly defined to enable a validation. Two component-level measurements of one machine tool and one industrial washing machine are analyzed. And then a cost analysis is conducted to determine the timespan that can be said to be time efficient for a validation procedure. The results from this are used to develop a validation method and an interactive protocol to make the validation more user friendly. This method is then tested through a simulated validation.

    The method proposed consists of two parts, an inspection and a measurement. The inspection is purely visual and validates the requirements on efficiency class for electrical motors and pumps, as well as requirements of specific equipment. The measurement is performed by running the machine through four different machine states in eight steps and validates requirements on when energy is used, and how much is used. The proposed method validates all energy efficiency requirements set by Scania for machine tools and industrial washing machines. It can be performed in a timespan that is far shorter than what is cost efficient. The proposed method can validate requirements on the energy use from any electrical components, compressed air use, and visually confirm that required equipment is present and some of its properties based on labelling. It will also be able to validate any new requirements on the energy use of electrical components, meaning it can easily be applied to other types of production equipment.

  • Bila, Kristi
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
    Fatigue Analysis of a Lively Footbridge2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The commitment of building aesthetic bridges made of stiff materials results in theconstruction of slender structures highly susceptible to dynamic loading. In the caseof footbridges located over a highly trafficked highway, such dynamic loads maybe the aerodynamic pressure induced by the heavy trucks passing underneath thestructure and the pedestrian loading involving a pedestrian running and jumping.There have been reported cases in the literature that these types of dynamic eventscan cause discomfort to the users of the bridge, and thus, footbridges are usuallychecked in the serviceability limit state. However, footbridges are not checked forfatigue damage since the design codes do not demand fatigue analysis.In the present master thesis, a hypothesis is made: the dynamic loading actingon footbridges can cause fatigue damage. To test this hypothesis, a case study wasconsidered. The Smista bridge was chosen, which is a footbridge with noticeablevibrations even with the single action of a pedestrian running on the bridge oreven when a single truck passes underneath the bridge. The bridge was simulatednumerically using a 3D shell finite element model. Four load cases were studied:the aerodynamic pressure induced by the heavy trucks passing below the bridge,the pedestrian jumping in the middle of the bridge, the pedestrian running in thecenterline of the bridge and the pedestrian running near the edge of the bridge.The results showed that the dynamic events applied on the bridge did not producehigh enough response and stresses to account for fatigue damage accumulation.Therefore, it is concluded that fatigue design of such bridges, although very livelyand which can cause high discomfort to people, should not be added as a designcriteria in the design codes.

  • Rylander, Katarina
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Urban and Regional Studies.
    Municipalities' ability to adapt the existing built environment to the changing climate: A case study of Täby, Vellinge, and Gothenburg2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    One of the most challenging issues within the planning and development process of our cities and societies is the changing climate that already can be seen in several parts of the world. To be able to decrease the cities’ and societies’ vulnerability towards these projections it is important to actively work with climate adaptation. Today, the majority of the climate adaptation measures are implemented in new developments, and not in the same extent in the existing built environment. Because the projected climate changes will affect all parts of the cities and societies it is important to work with an overarching climate adaptation. Within the Swedish context, the municipality has an important role in the work with climate adaptation. The aim of this master thesis is to generate an understanding of how Swedish municipalities work with climate adaptation within the existing built environment, and what challenges they face within their work. Additionally, the study will look at how the current legislation affects the municipal climate adaptation work, and how the new amendments in PBL, will affect the municipalities’ work. Three municipalities (Täby, Vellinge, and Gothenburg) have been studied to be able to conduct this master thesis, where sixteen interviewees from the municipalities, as well as from the Stockholm County Administrative Board and from Sweco, a Swedish consulting company, have been interviewed. The results from the study show that several challenges that the municipalities, in the current situation, are facing and are affecting their climate adaptation work. The main challenges that was identifies were the uncertain forecasts, the political will and priorities, the division of responsibility, the financial responsibility, and conflicting legislations. These challenges are creating limitations and difficulties for the municipalities to act in the issue of adapting to the changing climate, especially within the existing built environment. In the current situation, the three studies municipalities have started their climate adaptation work but are facing difficulties with going forward in the process.

  • Johansson, Jonas
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Jonsson Ewerbring, Marcus
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Användning av sensordata för att detektera smartphoneanvändares transportmedel2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A way to inform smartphone users about their climate impact is by automatically identifying their means of transport and use the information to estimate the user's emissions of greenhouse gases. The aim of this project was to create an overview of existing solutions and methods for detecting smartphone users' means of transport and evaluating how a system performs when test data is collected in a different geographical area than the data used to train the system. Evaluation of the system was done via quantitative methods where sensor data was collected and used to test the system. Sensor data was collected by walking, still, train, bus and car. The result is a system that, with varying probability, can determine the means of transport in Sweden. The system's total accuracy was 29 percentage points lower when data collected in Sweden was used in the tests compared to data collected in the same geographical area as the training data. The conclusion is that it can be problematic to apply a solution in a different geographical area than where the solution was developed for. The tests showed that vehicle detection seems particularly sensitive to changing geographical context.

  • Sonono, Tofik
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS.
    Interoperable Retransmission Protocols with Low Latency and Constrained Delay: A Performance Evaluation of RIST and SRT2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The media industry has during the last decade migrated services from dedicated medianetworks to more shared resources and lately also the public internet and public data centers. Inorder to cater for such transition, several protocols have been designed to meet the demand forhigh-quality media transport over lossy infrastructure, protocols such as SRT and RIST. Thepurpose of Reliable Internet Stream Transport (RIST) and Secure Reliable Transport (SRT) is tohave all vendors of broadcasting equipment support an interoperable way of communication. Thelack of interoperability locks consumers into one particular vendor’s family of products - most oftenthis equipment only supports a proprietary technology. Interoperability creates a more competitivemarket space which benefits consumers and gives vendors an incentive to be more innovative intheir solutions.

    The purpose of this thesis is to assess the performance of these protocols by comparing theirperformance to a proprietary solution (named ÖÖÖ in this thesis and seen as an establishedsolution in the industry). The challenge is to test these protocols in a lab environment, but have theresults represent real-world use. For this, a large subset of samples is needed along with samplesmeasured over a long period. This sampling was made possible by writing a script which automatesthe sampling process.

    The results indicate that the versions of RIST and SRT tested in this thesis to some extentcompare well to the selected established protocol (ÖÖÖ). In many scenarios, SRT even did muchbetter, mainly when a line with a single feed was tested. For instance, when the network suffered a2% drop rate and utilized retransmission SRT performed the best and was the only protocol whichhad some samples where no packets were dropped during one hour of measurements. Whenrunning all three protocols at the same time, SRT also did the best in a network with up to 12% droprate. The results in this thesis should give a broadcaster an idea of which of these protocols willfulfill their requirements in a broadcast application.

  • Müller, Matias I.
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control.
    Rojas, Cristian R.
    KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control.
    Gain estimation of linear dynamical systems using Thompson Sampling2019In: Proceedings of Machine Learning Research / [ed] Kamalika Chaudhuri, Masashi Sugiyama, 2019, Vol. 89, p. 1535-1543Conference paper (Refereed)
  • Public defence: 2019-09-13 13:00 Sal B, Kista
    Sollami Delekta, Szymon
    KTH, School of Electrical Engineering and Computer Science (EECS), Electronics.
    Inkjet Printing of Graphene-based Microsupercapacitors for Miniaturized Energy Storage Applications2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Printing technologies are becoming increasingly popular because they enable the large-scale and low-cost production of functional devices with various designs, functions, mechanical properties and materials. Among these technologies, inkjet printing is promising thanks to its direct (mask-free) patterning, non-contact nature, low material waste, resolution down to 10 µm, and compatibility with a broad range of materials and substrates. As a result, inkjet printing has applications in several fields like wearables, opto-electronics, thin-film transistors, displays, photovoltaic devices, and in energy storage. It's in energy storage that the technique shows its full potential by allowing the production of miniaturized devices with a compact form factor, high power density and long cycle life, called microsupercapacitors (MSCs). To this end, graphene has a number of remarkable properties like high electrical conductivity, large surface area, elasticity and transparency, making it a top candidate as an electrode material for MSCs.

    Some key drawbacks limit the use of inkjet printing for the production of graphene-based MSCs. This thesis aims at improving its scalability by producing fully inkjet printed devices, and extending its applications through the integration of inkjet printing with other fabrication techniques.

    MSCs typically rely on the deposition by hand of gel electrolyte that is not printable or by submerging the whole structure into liquid electrolyte. Because of this, so far large-scale production of more than 10 interconnected devices has not been attempted. In this thesis, a printable gel electrolyte ink based on poly(4-styrene sulfonic acid) was developed, allowing the production of large arrays of more than 100 fully inkjet printed devices connected in series and parallel that can be reliably charged up to 12 V. Also, a second electrolyte ink based on nano-graphene oxide, a solid-state material with high ionic conductivity, was formulated to optimize the volumetric performance of these devices. The resulting MSCs were also fully inkjet printed and exhibited an overall device thickness of around 1 µm, yielding a power density of 80 mW cm-3.

    Next, the use of inkjet printing of graphene was explored for the fabrication of transparent MSCs. This application is typically hindered by the so-called coffee-ring effect, which creates dark deposits on the edges of the drying patterns and depletes material from the inside area. In light of this issue, inkjet printing was combined with etching to remove the dark deposits thus leaving uniform and thin films of graphene with vertical sidewalls. The resulting devices showed a transmittance of up to 90%.

    Finally, the issue of the substrate compatibility of inkjet printed graphene was addressed. Although inkjet printing is considered to have broad substrate versatility, it is unreliable on hydrophilic or porous substrates and most inks (including graphene inks) require thermal annealing that damages substrates that are not resistant to heat. Accordingly, a technique based on inkjet printing and wet transfer was developed to reliably deposit graphene-based MSCs on a number of substrates, including flat, 3D, porous, plastics and biological (plants and fruits) with adverse surfaces.

    The contributions of this thesis have the potential to boost the use of inkjet printed MSCs in applications requiring scalability and resolution (e.g. on-chip integration) as well as applications requiring conformability and versatility (e.g. wearable electronics).

  • Bouju, Cecile
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Igergård, Fanny
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Wasted Potential: Potential of a food waste prevention model for the São Paulo street markets - A minor field study2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In the municipal kitchens of Gothenburg, the implementation of the Gothenburg Model for reduced food waste has resulted in reducing the food waste by half in two years. The objective of this study is to contribute in the work of food waste prevention at the street markets in São Paulo by investigating how a model like the Gothenburg Model could be created and implemented. The study has mainly been carried out through a field study on a selection of street markets in São Paulo by performing observations, interviews and estimations of the food waste quantities. The findings of the study are that a model alike the Gothenburg Model could be of relevance at the street markets. It was found that both the model as a tool and as a process could be of use, with the phase of motivating and training the workers having special importance. The social responsibility felt by the vendors has been identified as a great opportunity to present not only donation but also food waste prevention as a social issue. The heterogeneity between the different market stalls and the lack of management on each market presents a challenge in the development and implementation of a tool. Further work should therefore be done to find solutions applicable to the various vendors and to investigate the eventual existence of natural leaders.

  • Public defence: 2019-09-12 13:00 F3, Stockholm
    Bütepage, Judith
    KTH, School of Electrical Engineering and Computer Science (EECS), Robotics, Perception and Learning, RPL.
    Generative models for action generation and action understanding2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The question of how to build intelligent machines raises the question of how to rep-resent the world to enable intelligent behavior. In nature, this representation relies onthe interplay between an organism’s sensory input and motor input. Action-perceptionloops allow many complex behaviors to arise naturally. In this work, we take these sen-sorimotor contingencies as an inspiration to build robot systems that can autonomouslyinteract with their environment and with humans. The goal is to pave the way for robotsystems that can learn motor control in an unsupervised fashion and relate their ownsensorimotor experience to observed human actions. By combining action generationand action understanding we hope to facilitate smooth and intuitive interaction betweenrobots and humans in shared work spaces.To model robot sensorimotor contingencies and human behavior we employ gen-erative models. Since generative models represent a joint distribution over relevantvariables, they are flexible enough to cover the range of tasks that we are tacklinghere. Generative models can represent variables that originate from multiple modali-ties, model temporal dynamics, incorporate latent variables and represent uncertaintyover any variable - all of which are features required to model sensorimotor contin-gencies. By using generative models, we can predict the temporal development of thevariables in the future, which is important for intelligent action selection.We present two lines of work. Firstly, we will focus on unsupervised learning ofmotor control with help of sensorimotor contingencies. Based on Gaussian Processforward models we demonstrate how the robot can execute goal-directed actions withthe help of planning techniques or reinforcement learning. Secondly, we present anumber of approaches to model human activity, ranging from pure unsupervised mo-tion prediction to including semantic action and affordance labels. Here we employdeep generative models, namely Variational Autoencoders, to model the 3D skeletalpose of humans over time and, if required, include semantic information. These twolines of work are then combined to implement physical human-robot interaction tasks.Our experiments focus on real-time applications, both when it comes to robot ex-periments and human activity modeling. Since many real-world scenarios do not haveaccess to high-end sensors, we require our models to cope with uncertainty. Additionalrequirements are data-efficient learning, because of the wear and tear of the robot andhuman involvement, online employability and operation under safety and complianceconstraints. We demonstrate how generative models of sensorimotor contingencies canhandle these requirements in our experiments satisfyingly.

  • Wernius, Emma
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Olausson, Hanna
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Sekkenes, Martina
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Optimization of a solar water pumping system in Progreso, Amazonas, Colombia: Minor field study2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In the villages along the Amazon river, the access to clean drinking water is lacking. In Progreso, the Swedish foundation Ankarstiftelsen and the non-governmental organization Entropika have installed a water purification system to solve this problem. The water used in the purification system is today pumped from a tributary to the Amazon river with a gasoline pump. This comes with social, ecologic and economic problems. To solve these problems, a solar water pumping system has been developed. After a preparing literature study on the topic, a field study was done to find relevant data. From this, an Excel program was made to optimize a suitable solution. Together with suggestions from three companies, two with a surface pump and one with a submersible pump, the system including a submersible pump was considered the most preferable. This mainly due to lower cost, weight and maintenance. Further, the suggestions were used to control the accuracy of the developed Excel program. This program can be used for future optimizations of systems with similar character.

  • Ebrahim, Mila
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Lilja, Fanny
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    The feasibility of producing and utilizing bioenergy in Linga Linga, Mozambique: Potential resources, conversion techniques and applications2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The aim of the project was to investigate the possibility of producing and utilizing bioenergy from available local resources in the village Linga Linga, Mozambique. Suitable conversion techniques for producing and utilizing bioenergy were identified through a literature study. The investigated techniques were the concept of gasifier cookstoves, the method of producing charcoal from biomass and anaerobic digesters. Through observations and interviews in the village, available local resources suited for the conversion techniques were identified. In the field study, it was found that there is a surplus of solid biomass which led to the conclusion that a gasifier cookstove is suitable to implement. In order to analyze if a gasifier cookstove is suitable for the households, interviews were carried out in ten households in the village. Aprototype of a gasifier cookstove was built with local resources to determine if the technique can be applied. The prototype was tested and evaluated in order to analyze if it will contributeto a more efficient use of resources. One of the conclusions of the study was that a gasifier cookstove can be valuable for the households in several ways, but that cultural differences can make it hard to implement.

  • Belaieff, Vera
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Barns mobilitet: En analys av barns skol- och fritidsresor samt det kommunala arbetet kring de respektive resorna2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Just like adults, children travel regularly in their everyday life. A major part of children’s travels goes to school, but apart from that children also do leisure travels to club activities and leisure facilities. The everyday travel habits of children affect both their health and independence. For this reason, this thesis will embrace children’s mobility and sustainable everyday travels. The aim is to raise the different travel types of children as well as present a basis for continued work within the topic.

    The study contains of literature research and questionnaires. One of the surveys was made in collaboration with Järfälla municipality. The two questionnaires, one for the students and one for their parents, investigated the travels habits to school and leisure activities for children in Skälbyskolan. Another questionnaire was sent to municipalities in the network of ResSmart. This survey collected information about if and how the municipalities work with children’s school travels and leisure travels, including also the reason why in some cases nothing was done.

    The result of the surveys showed that walking and cycling are the most common ways of transport to school. Most of the travels was done alone or with other children. Considering the use of bicycle, the use is dependent on the time of the year, where a large proportion cycle in summer but few in winter. To leisure activities, a great majority of the travels are made by car. Because of this, the independence of children’s leisure travel is generally non-existing. The reason why parents drive their children to leisure activities mainly depends on the distance, but also the time of the day in relation to darkness and the general family life. When driving children to school, the main reasons are lack of time and continued travels by car.

    When comparing Skälbyskolan with Gustav Vasa skola in the downtown of Stockholm, the result showed that walking is to most popular way of travel for both schools. However, neither cycling nor driving was made regularly to Gustav Vasa skola, even if the reasons when actually driving was the same as in Skälbyskolan.

    Regarding the municipality planning and actions, it is more common that municipalities work with sustainable school travels than children’s leisure travels. Furthermore, the working methods differ, where only physical arrangements are made within leisure travel routes and the lack of mobility management is a fact.

    With basis in the literature and survey results, action proposals are presented for a developed work within the area. For school travels, the actions should focus on reaching the parents and affecting their choice of mode, as well as actions for easier and more comfortable cycling during winter season. Considering leisure travels is the proposal to copy actions from the work with school travels, where the work should start off with inventions and travel habits surveys in leisure clubs. Furthermore, mobility management actions should be introduced, but also complex and long-term actions including leisure buses for children as well as compact city planning.

    Finally, the study mean that further work and surveys are needed for continued and developed work with children’s mobility. The area of children’s leisure travels should be raised both in planning documents and information, but also is media and larger forums.

  • Rosenberg, Barbro
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Tenfält, Markus
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Energy Scheme Proposal for Small Sugar Mills for Maximum Power Generation and Bagasse Saving during Harvesting Season2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Energy systems have significant importance for social development, not least in developing countries. A well-developed energy system can contribute to economic, ecological as well as social sustainability. At the same time, the ambitions to globally reduce dependence on fossil-based fuels and the climate impacting emissions that accompany them increase. To achieve this, energy efficiency improvements and an increased share of renewable energy sources are required. Today, there are both great challenges and opportunities in developing energy systems in developing countries and at the same time reducing the global climate impact.

    Thanks to the sugar industry in Cuba, there are great opportunities for the country to develop its electricity production from biofuels in the form of bagasse, a residual product which is provided during the process of the production of sugar. This report examines the possibility of developing the energy system in the sugar factory Carlos Baliño, located in Villa Clara in Cuba. The purpose is to enable the factory to minimize its use of bagasse and to maximize electricity production. This is to provide the opportunity for the factory to become more economical and ecologically sustainable.

    The current energy system in the sugar industry was examined and a model of the energy flows was created in excel. Based on the current energy system, four different scenarios were then examined with potential improvements. These four scenarios were as follows; (1) Preheating, (2) Bagasse drying, (3) Increase inlet boiler pressure and (4) New generator. For the various scenarios, the energy flow schemes were defined and technical components were selected. An economic and ecological analysis based on the best possible parameters of the scenarios was then performed.

    The result showed that the marginal electricity demand for the current system was 19 kWh per tonne of sugar cane and that the fixed electricity demand was 890 kW. The model defined the value of the bagasse as 8.2 USD per tonne, based on the current system. The current cut of costs by replacing oil were defined as 31 MUSD and the total amount of saved carbon dioxide was 96,000 tonnes, both for a period of 6 years. Out of the four scenarios that were investigated and compared with current systems, drying of bagasse was the option that could best be justified. This scenario resulted in a bagasse value of 5.0 USD per tonne, a cut of costs of 51 MUSD by replacing oil over a 6-year period and 150,000 tonnes of reduced carbon dioxide emissions over the same period.

    Preheating resulted in an increase in bagasse consumption, but also a higher electricity production. The result also showed that increasing the pressure in the boiler is not relevant, as the current pressure is almost the maximum for the current system. Due to a simplified model, Scenario 4, which included the investment of a new generator, could not be tested.

  • Public defence: 2019-09-06 10:00 F3, Stockholm
    Abdalmoaty, Mohamed
    KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control. KTH Royal Institute of Technology.
    Identification of Stochastic Nonlinear Dynamical Models Using Estimating Functions2019Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Data-driven modeling of stochastic nonlinear systems is recognized as a very challenging problem, even when reduced to a parameter estimation problem. A main difficulty is the intractability of the likelihood function, which renders favored estimation methods, such as the maximum likelihood method, analytically intractable. During the last decade, several numerical methods have been developed to approximately solve the maximum likelihood problem. A class of algorithms that attracted considerable attention is based on sequential Monte Carlo algorithms (also known as particle filters/smoothers) and particle Markov chain Monte Carlo algorithms. These algorithms were able to obtain impressive results on several challenging benchmark problems; however, their application is so far limited to cases where fundamental limitations, such as the sample impoverishment and path degeneracy problems, can be avoided.

    This thesis introduces relatively simple alternative parameter estimation methods that may be used for fairly general stochastic nonlinear dynamical models. They are based on one-step-ahead predictors that are linear in the observed outputs and do not require the computations of the likelihood function. Therefore, the resulting estimators are relatively easy to compute and may be highly competitive in this regard: they are in fact defined by analytically tractable objective functions in several relevant cases. In cases where the predictors are analytically intractable due to the complexity of the model, it is possible to resort to {plain} Monte Carlo approximations. Under certain assumptions on the data and some conditions on the model, the convergence and consistency of the estimators can be established. Several numerical simulation examples and a recent real-data benchmark problem demonstrate a good performance of the proposed method, in several cases that are considered challenging, with a considerable reduction in computational time in comparison with state-of-the-art sequential Monte Carlo implementations of the ML estimator.

    Moreover, we provide some insight into the asymptotic properties of the proposed methods. We show that the accuracy of the estimators depends on the model parameterization and the shape of the unknown distribution of the outputs (via the third and fourth moments). In particular, it is shown that when the model is non-Gaussian, a prediction error method based on the Gaussian assumption is not necessarily more accurate than one based on an optimally weighted parameter-independent quadratic norm. Therefore, it is generally not obvious which method should be used. This result comes in contrast to a current belief in some of the literature on the subject. 

    Furthermore, we introduce the estimating functions approach, which was mainly developed in the statistics literature, as a generalization of the maximum likelihood and prediction error methods. We show how it may be used to systematically define optimal estimators, within a predefined class, using only a partial specification of the probabilistic model. Unless the model is Gaussian, this leads to estimators that are asymptotically uniformly more accurate than linear prediction error methods when quadratic criteria are used. Convergence and consistency are established under standard regularity and identifiability assumptions akin to those of prediction error methods.

    Finally, we consider the problem of closed-loop identification when the system is stochastic and nonlinear. A couple of scenarios given by the assumptions on the disturbances, the measurement noise and the knowledge of the feedback mechanism are considered. They include a challenging case where the feedback mechanism is completely unknown to the user. Our methods can be regarded as generalizations of some classical closed-loop identification approaches for the linear time-invariant case. We provide an asymptotic analysis of the methods, and demonstrate their properties in a simulation example.

  • FERNANDEZ BARRERO, DIEGO
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
    Dynamic Soil-Structure Interactionof Soil-Steel Composite Bridges: A Frequency Domain Approach Using PML Elements and Model Updating2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This master thesis covers the dynamic soil structure interaction of soil-steel culverts applyinga methodology based on the frequency domain response. At the first stage of this masterthesis, field tests were performed on one bridge using controlled excitation. Then, themethodology followed uses previous research, the field tests, finite element models (FEM)and perfectly matched layer (PML) elements.Firstly, a 2D model of the analysed bridge, Hårestorp, was made to compare the frequencyresponse functions (FRF) with the ones obtained from the field tests. Simultaneously, a 3Dmodel of the bridge is created for the following purposes: compare it against the 2D modeland the field tests, and to implement a model updating procedure with the particle swarmalgorithm to calibrate the model parameters. Both models use PML elements, which areverified against previous solution from the literature. The verification concludes that thePML behave correctly except for extreme parameter values.In the course of this master thesis, relatively advanced computation techniques were requiredto ensure the computational feasibility of the problem with the resources available.To do that, a literature review of theoretical aspects of parallel computing was performed, aswell as the practical aspects in Comsol. Then, in collaboration with Comsol Support and thehelp given by PDC at KTH it was possible to reduce the computational time to a feasiblepoint of around two weeks for the model updating of the 3D model.The results are inconclusive, in terms of searching for a perfectly fitting model. Therefore,further research is required to adequately face the problem. Nevertheless, there are some accelerometerswhich show a considerable level of agreement. This thesis concludes to discardthe 2D models due to their incapability of facing the reality correctly, and establishes a modeloptimisation methodology using Comsol in connection with Matlab.

  • Gustafson, Daniel
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Urban and Regional Studies.
    Hur urban täthet och rymlighet hanteras i Hagastaden2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Urban density is an ideal that characterizes today's urban planning in Sweden. This is evident from various general planning documents as well as the densification projects, e.g. Hagastaden in Stockholm, which are a result of these. This paper aims to find an understanding of how urban density and spaciousness are balanced in Hagastaden, and how Hagastaden resembles or differs from other development areas in this respect. Hagastaden and Norra Djurgårdsstaden, another densification project in Stockholm, are compared with respect to density, partly at an area level and partly at a block level. As for the area level, the floor space index (FSI) is calculated for an entire detailed development plan area. In Hagastaden’s plan area DP1 and in Norra Djurgårdsstaden plan area etapp Västra. As for the block level, the floor space index (Swedish: nettoexploateringstal), land use (Swedish: andel bebyggd mark) and spaciousness index (Swedish: rymlighetstal) are calculated, as defined by Rådberg et al (1996), for one block in each area. The block Cellen is chosen in Hagastaden and in Norra Djurgårdsstaden the block Töfsingdalen. These blocks are also compared with the main groups of Swedish city types as described by Rådberg et al. Hagastaden's public open spaces, i.e. park and square areas, are analyzed based on guidelines from the document Grönare Stockholm and the so called Alviksmodellen. The result of the density comparison shows that Hagastaden is considerably denser than both Norra Djurgårdsstaden and the main groups of Swedish city types. DP1 in Hagastaden has an area-wide floor space index of 2.54, compared to 1.65 for etapp Västra in Norra Djurgårdsstaden. Furthermore, the housing block Cellen in Hagastaden has a floor space index of 4.20, compared to 2.57 for Töfsingdalen in Norra Djurgårdsstaden. Both blocks exceed all main groups of Swedish city types with respect to floor space index, but most closely resemble the main group Big city blocks (Swedish: Storstadsmässiga kvarter). The difference in floor space index seems to be mainly due to the difference in number of floors, where the block Cellen has an average number of 11.1 floors and the block Töfsingdalen 7.1 floors. DP1 in Hagastaden, with a 16.7 % share of public open space, achieves the Alviksmodellen guideline of at least 15% public open space. However, it does not achieve the guideline of at least 10 m2 of public open space per resident with only 6 m2 per resident. Furthermore, the guidelines for good access to park and nature are only partly met.

  • Carlson, Douglas
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Urban and Regional Studies.
    Out-of-Character: Current and Potential Use of 'Character' in the Development of Swedish Urban Areas2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Character is a term used in urban development and research to describe aspects of the built environment ranging from aesthetics and design to place identity and sense of place. This wide range of interpretations has led to a vague understanding that differs depending on the perception of users and actors in urban development. In the face of increasing housing demands and incentives to expand, Swedish urban environment has begun expansion that mirrors that of the Million Programme. To avoid a detached environment, character is investigated and proposed to be used as a tool for municipalities in the development. The focus is on answering what ‘character’ is perceived as by municipal officials involved in the urban development process, how character should be used and lastly how character should be approached when developing existing areas. Based on interviews for a practical understanding, literature for a theoretical understanding and contemporary studies for a contextual understanding, character is found to be perceived as the connection between not only existing buildings but also new ones as well as the users themselves. With emphasis on cohesion, originality, traditionality, diversity among other attributes, the character of an area should act as a binding agent for urban development moving forward. Finally, the approach to character is recommended to be cautious based on its vague nature but be treated as exploratory where a base set of two foundational attributes are to invite discussion to bridge the perceptions between actors.

  • Fröjd, Felicia
    KTH, School of Industrial Engineering and Management (ITM). KTH.
    Evaluation of quantification methods for inclusion distribution in clean steel2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Ovako products are in many cases used in high fatigue applications. Currently Ovako use ultrasonic evaluation at 10 MHz as a volumetric method for inclusion control. This study intends to investigate two new methods for quantification of micro inclusions.The aim of this study is to develop a method for large area scanning by creating a polishing method that allows you to polish away a specified amount of material, in this case 60 μm. This method will be used to capture the true distribution of critically sized non-metallic inclusions by creating a 3D image out of several 2D scans from the light optical microscope. These results will be compared to the results of high frequency ultrasonic testing at 125 MHz to get a quantitative idea of what can be captured by the high frequency ultrasonic investigation.Two different steel grades were studied, named Grade A and Grade B, with one sample of each. Both grades have similar composition, except that Grade B contains more sulphur. Both grades are of approximately the same hardness. The two steel samples were scanned with a scanning acoustic microscope at the same time as a method to polish away 60 μm was developed. After this, the method was used to scan several layers with an image recognition program in the light optical microscope. The results from both methods were then compared.After testing, it was concluded that the inclusion distribution pattern was completely different for the two steel grades, however the same pattern could be seen for each grade in the LOM and in the ultrasonic. This indicates that the same types of inclusions could be found. It was also found that the ultrasonic enlarges the indications by a severe amount making it hard to take any measurements directly from the ultrasonic images in this study. What is possible to see in the ultrasonic images are the distribution of inclusions and the inclusion placement in the sample. A result of 10 % matching inclusions between both methods is found, which is to say that the same 50 inclusions out of the 500 largest indications from each method in the steel sample is found. These 10 % is however not sufficient enough to conclude by how much the ultrasonic enlarges the indications compared to the light optical microscope.