1234567 51 - 100 of 495
rss atomLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
  • Pavlovic, Boban
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Dynamic Performance Analysis of a Fighter Jet with Nonlinear Dynamic Inversion2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    A modern view of aircraft performance analysis, is to quantify aircraft manoeuvrability with agility metrics. There are several different agility metrics, which can be seen as indexing of the aircraft agility performance. The quantified unit is the time it takes for the aircraft to perform a specific manoeuvre relevant to a given agility metric. In this thesis, estimations are done of two agility metrics, the CCT (Combat Cycle Time) and the T90 (Time to capture 90◦ bank angle) for the F-18 HARV aircraft.Estimations of the agility metrics were obtained by simulating a six-degree-of-freedom aircraft model of the F-18 HARV aircraft performing the specific manoeuvres. To control the aircraft model during the simulation a control sys-tem was developed based on the NDI (Nonlinear Dynamic Inversion) method with time scale separation assumption. The method uses the feedback from the controlsystem for linearizing the aircraft system, which results in that simple linear controllers can be applied to the nonlinear aircraft model.In this case simple proportional controllers were implemented and in the case of estimating the T90 agility metric additional gain scheduling as functions of altitude and Mach number was required to extract maximum performance. Although the control system was developed for these two specific agility metrics, results indicates that the NDI method provides an effective way to implement controllers for complex systems, especially when considering a high nonlinear flight regime.

  • Ekman, Fanny
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Marina system.
    Operationalizing the SDGs in a Systems Engineering Framework for ship design concept studies2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Sustainable transport involves more choices and possibilities than ever before, and the topic is widely discussed within the maritime industry.

    To a large extent the innovations and technology exists, but even though there is a drive and consciousness to change, sustainability is still not a cornerstone in the decision-making process when new ships and transport solutions are developed. The gap between sustainability ambitions and actual actions is far from closed.

    This thesis introduces a new framework called Systems Engineering for Sustainable Ship design (SE4SS), which is based on the Systems Engineering methodology for conducting concept developments and the Sustainable Development Goals (SDG) for operationalizing sustainability.

    The new framework makes sustainability aspects an essential part of ship design concept development and the following decision-making process.

    The SE4SS framework includes an application of the SDGs on a product level (ship) and suggests appropriate tools & methods for sustainability assessment, considering different levels of ambitions and amount of available resources that projects may have.

    The framework has been validated against three cases of ship design concept development within the commissioner organization SSPA. The result shows that the suggested approach is useful in terms of ; (1) raising a holistic awareness of sustainability aspects in ship design, highlighting the existing opportunities and responsibilities, (2) creating a more transparent trade-off analysis where priorities need to be stated, preventing greenwashing, (3) structuring the process which facilitates the integration of sustainability aspects from the start and the communication between the project manager/naval architect and different stakeholders. Full-scale application of the SE4SS is needed in order to fully validate its usability and generalizability, however this thesis argues that the introduced framework may be a valuable tool in both illuminating and reducing the ambition-action gap within the maritime sector.

  • Díaz Vázquez, Guillermo
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Case Data Analysis Tool for PowerFLOW2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The field of computational fluid dynamics (CFD) is exponentially growing in terms of performance, robustness, and applications. The expansion of CFD also means more users and more simulations, which translates into more human errors and mistakes in the simulation set up. Because the simulation set up should be the correct in order to accurately reproduce the desired phenomenon, such errors must be mitigated in order to increase the reliability and robustness of the simulations. In this project a tool has been developed to tackle this issue, within the CFD software SIMULIA PowerFLOW. The tool extracts and analyzes the data of the cases before simulation, reporting the results to the user for error detection. The present work aims to present the implementation, the application and the benefits of the designed tool.

  • Chea, Ming Kai
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner.
    Investigating In-plane Shear Behaviour of Uncured Unidirectional Prepreg Tapes2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Steering of prepreg tows in an automated fibre placement (AFP) process allows geodesic layup trajectory over a doubly-curved surface, as well as the potential to improve the efficiency of composite structures by tailoring their stiffness. However, defects (such as out-of-plane buckling and tow pull off) are commonly generated when the steering radius exceeds a critical limit, which impact the mechanical properties of the finished product.

    The in- and out-of-plane material properties of the prepreg tows have been shown to significantly influence the quality of the layup. In this thesis, in-plane shear behaviour of uncured IMA-M21 unidirectional (UD) prepreg was characterised using an off-axis tensile test to derive material parameters for process models to predict steering limits and defects.

    Test parameters, such as shear strain rates and temperatures, that were investigated were consistent to the actual AFP process. The results demonstrates the expected strain-rate and temperature dependencies related to the resins viscoelastic behaviour. Subsequently, a novel micro-mechanical finite element (FE) simulation of a 3-dimensional UD prepreg unit cell in pure shear was conducted to gain qualitative insights into the complex rheological behaviour at play. It effectively demonstrates how fibre friction, resin viscosity and shear strain rates influence the load transfer between fibres and melt, as well as the movement of fibres during the shearing process. These were reflected in the shear stress-strain curves generated in the simulation and elastic micro-buckling observed in the fibre elements. The results pave a way for future development of a robust material model for predicting the critical process parameters to achieve quality layups from AFP steering process.

  • Källgren, Tom
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Nordling, Olof
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Community Supported Agriculture” i Sverige: Modellens bidrag till ett hållbart livsmedelssystem2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Runtom i världen finns många modeller, mål och visioner för en hållbar utveckling, och många av dessa kan kopplas till jordbruk. Livsmedelsproduktion är en av de viktigaste industrierna vi har och är även källan till en stor del av utsläpp, färskvattenanvändning, övergödning och annan problematik kring miljö, ekonomi, levnadsvillkor och mycket mer. För att säkra en hållbar utveckling för samhället i stort är alltså produktionen av mat en viktig pusselbit, men utvecklingen de senaste hundra åren har gått mot en intensifiering, globalisering och mekanisering av jordbruket utan dess like.

    Som en motreaktion på detta har flera alternativa livsmedelssystem utvecklats med olika skalor, utgångspunkter och resultat. Ett av dessa system är konceptet Community Supported Agriculture (CSA), eller andelsjordbruk som det kallas på svenska. Konceptet utvecklades redan på 60-talet i Europa och Japan och kom till USA på 80-talet där det sedan dess har expanderat enormt, men i Sverige är det fortfarande relativt nytt och kunskapen kring andelsjordbruk är liten. De flesta av det 50-tal CSA-gårdar som finns i landet har tillkommit de senaste åren och för konsumenter, lagstiftare och jordbrukare finns ännu inte det forskningsunderlag som krävs för att fatta beslut kring och släppa fram utvecklingen av konceptet.

    Detta arbete ämnar att lyfta fram de sätt som CSA-modellen kan bidra till en hållbar utveckling. Detta genom att genomföra en litteraturstudie om modellen och hållbara livsmedelssystem i allmänhet och sedan koppla resultaten till de uppsatta målen för hållbar utveckling som finns på global, nationell och lokal nivå. Från resultaten görs även jämförelser med en fallstudie-referens, CSA-gården Under Tallarna i Södertälje. Resultaten indikerar att CSA har mycket att bidra med i flera aspekter av hållbar utveckling. Utöver hållbar produktion av livsmedel finns det nyttor bland annat inom hälsa, ekonomi, utveckling av landsbygd, lokalsamhällen och kultur. För att uppnå de satta hållbarhetsmålen krävs en omställning av livsmedelssystemet och det konventionella jordbruket i dess kärna. Resultatet av studien visar att CSA-konceptet, med stöd från intressenter i och kring livsmedelssystemet, har potential att möjliggöra en sådan omställning.

  • Tegbrant, Kerstin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Cost-effectiveness of ergonomic interventions - Evaluation of a calculation model2019Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Several studies have shown that the work environment affects company performance. The managers are seldom aware to which extent work environment problems affect productivity, quality of delivery and sick-leave in their organisation. The present literature study showed that improvements regarding physical ergonomics generally are shown to be cost-effective. The most beneficial way of working is through proactive measures interactively with employees. An efficient, systematic way of performing risk assessments and interventions reduce the need for a calculation method. This study identified propositions for properties of calculation methods. These propositions were : “Simplicity, high usability”, “Right content for the target group”, “High ability to measure risk”, “Focus on staff”, “Correct standardised values”, “Right focus” and “Optimal design”. Scania CV, a producer of trucks and buses, has developed a calculation model for cost-effectiveness of ergonomic interventions. Evaluation of this model with semi-structured interviews showed agreement regarding the need of a simplified calculation method, based on systematic risk assessments.

  • Zec, Kenan
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem.
    Hansson, Sofia
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem.
    Home Care Logistics: A Monitoring System with a Communication Unit for the Elderly2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Humans are growing older which presents challenges for the health care system. One solution for allowing individuals to continue living in their home, despite age related dif- ficulties, is a sensor based surveillance system. These systems can monitor a number of parameters, for example motion or temperature. If certain limits are exceeded the sys- tem can notify family members or health care services. The aim of this project was to build a prototype of such a system which also had to be cheap and easy to install and maintain. The final prototype consists of a motion detection sensor in the bathroom, a temperature sensor around the kitchen stove and a temperature sensor for measurement of ambient room temperature. Each sensor is connected to its own Arduino and they are all programmed with different limits. The sensors communicate wirelessly with a central hub through the communication protocol LoRa. Once the central hub, which consists of a Raspberry Pi, receives a LoRa signal it sends an email to a chosen address.

  • Storfeldt, Joakim
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Design benefits with Additive Manufacturingfrom a convective heat transfer perspective2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Nowadays manufacturing processes are rapidly developing. Salt-bath dip brazing is a conventional manufacturing method commonly used by Saab AB to fuse aluminium components in a high temperature salt bath. However conventional manufacturing methods have shown some limitations. Additive Manufacturing, or 3D printing, is a newer technology which has become very popular in the industry offering competitive advantages regarding production time and size, and structural complexity of the components among other aspects. In this work, Additive Manufacturing is investigated to assess if the performance of heat sinks can be increased compared to the salt-bath dip brazing method.

    Geometrical shapes of heat sink-fins were studied by empirical research to compare their characteristics in air-flow, convection and pressure drop. Eight different geometrical shapes have been analyzed using Additive Manufacturing, and the control plate fins was used as a reference for comparison with salt-bath dip brazing. It was found out that the NACA 0010 fins and Square Grid fins geometries gave the best performance with a 63% and 64% decrease in pressure drop per diverted energy compared to the control plate fins, respectively.

  • Disputas: 2019-11-06 10:00 Kollegiesalen, Stockholm
    Song, Meng
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Planning and Operation of Demand-Side Flexibility2019Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Power systems are changing with growing penetration of non-dispatchable renewable generation and increased demand of electric energy. More generation, transmission or distribution capacities are needed to balance the varying production and higher consumption. Demand-side flexibility is a potential solutionto tackle those challenges. By shifting the consumption time and temporarily increase or decrease the power demand, the demand-side flexibility can help to integrate more wind and solar energy in the system, alleviate network congestion and postpone the investment for grid reinforcement. Therefore, technical and regulatory measures are undergoing in many countries to encourage demand response and engage customers.

    On the other hand, unlocking the flexibility will introduce more complexityand uncertainty on demand side. This would result in difficulties for different actors in power systems and power markets to make optimal decisionsin their planning and operation. The thesis addresses the problem by proposing methods to support the decision making of actors on demand side. Firstly, it develops models to facilitate residential customers and commercial electric vehicle fleet operators scheduling their shiftable appliances for reducing electricity cost. The willingness of households for responding to time-varying price is taken into account. Results from Stockholm Royal Seaport project are analysed to demonstrate such willingness. Secondly, the thesis develops models for the short-term planning of retailers and balance responsible players. Different approaches are deployed under price-taker and price-maker assumptions respectively. The planning concerns the price sensitivityof end customers and the risk related with certain bidding strategies.Thirdly, the thesis proposes models to coordinate and aggregate the flexible charging power of electric vehicles to provide regulation service on the balancing market. The models encompass the decision process from day-aheadplanning to real-time operation management. The proposed models in the thesis are based on the rules of Nordic electricity market and could be further developed for adapting to other market frameworks. Stochastic programmingis applied to address the uncertainties about consumption and market behaviours.In addition, the thesis discusses the impacts of demand response interms of generation cost, system reliability and market price. It shows that a widely implemented demand response can reduce the total generation cost, improve the reliability of supply and decrease the market price.

  • Disputas: 2019-12-03 10:00 Kollegiesalen, Stockholm
    Ahmed, Laeeq
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Beräkningsvetenskap och beräkningsteknik (CST).
    Scalable Analysis of Large Datasets in Life Sciences2019Doktoravhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    We are experiencing a deluge of data in all fields of scientific and business research, particularly in the life sciences, due to the development of better instrumentation and the rapid advancements that have occurred in information technology in recent times. There are major challenges when it comes to handling such large amounts of data. These range from the practicalities of managing these large volumes of data, to understanding the meaning and practical implications of the data.

    In this thesis, I present parallel methods to efficiently manage, process, analyse and visualize large sets of data from several life sciences fields at a rapid rate, while building and utilizing various machine learning techniques in a novel way. Most of the work is centred on applying the latest Big Data Analytics frameworks for creating efficient virtual screening strategies while working with large datasets. Virtual screening is a method in cheminformatics used for Drug discovery by searching large libraries of molecule structures. I also present a method for the analysis of large Electroencephalography data in real time. Electroencephalography is one of the main techniques used to measure the brain electrical activity.

    First, I evaluate the suitability of Spark, a parallel framework for large datasets, for performing parallel ligand-based virtual screening. As a case study, I classify molecular library using prebuilt classification models to filter out the active molecules. I also demonstrate a strategy to create cloud-ready pipelines for structure-based virtual screening. The major advantages of this strategy are increased productivity and high throughput. In this work, I show that Spark can be applied to virtual screening, and that it is, in general, an appropriate solution for large-scale parallel pipelining. Moreover, I illustrate how Big Data analytics are valuable in working with life sciences datasets.

    Secondly, I present a method to further reduce the overall time of the structured-based virtual screening strategy using machine learning and a conformal-prediction-based iterative modelling strategy. The idea is to only dock those molecules that have a better than average chance of being an inhibitor when searching for molecules that could potentially be used as drugs. Using machine learning models from this work, I built a web service to predict the target profile of multiple compounds against ready-made models for a list of targets where 3D structures are available. These target predictions can be used to understand off-target effects, for example in the early stages of drug discovery projects.

    Thirdly, I present a method to detect seizures in long term Electroencephalography readings - this method works in real time taking the ongoing readings in as live data streams. The method involves tackling the challenges of real-time decision-making, storing large datasets in memory and updating the prediction model with newly produced data at a rapid rate. The resulting algorithm not only classifies seizures in real time, it also learns the threshold in real time. I also present a new feature "top-k amplitude measure" for classifying which parts of the data correspond to seizures. Furthermore, this feature helps to reduce the amount of data that needs to be processed in the subsequent steps.

  • Putra, Ramadhani Pamapta
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Implementation and Evaluation of WebAssembly Modules on Embedded System-based Basic Biomedical Sensors2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    WebAssembly is a new binary code specification, which was initially designed to complement JavaScript in web applications. WebAssembly is inherently portable and small, designed for multiplatform usage. Therefore, WebAssembly modules can be created to support embedded system-based biomedical sensor operation. However, WebAssembly has its own limitations to compensate with its portability. In this thesis, we show how WebAssembly modules can be applied to the basic biomedical modalities of body temperature, heart rate, and breathing pattern.  We show how the implementation performed, and what challenges were met during the development. It is concluded that WebAssembly can be applied for achieving safe and effective biomedical sensor devices, although with some limitations.

  • Rahgozar, Parastu
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Evaluation of a Radiomics Model for Classification of Lung Nodules2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Lung cancer has been a major cause of death among types of cancers in the world. In the early stages, lung nodules can be detected by the aid of imaging modalities such as Computed Tomography (CT). In this stage, radiologists look for irregular rounded-shaped nodules in the lung which are normally less than 3 centimeters in diameter. Recent advancements in image analysis have proven that images contain more information than regular parameters such as intensity, histogram and morphological details. Therefore, in this project we have focused on extracting quantitative, hand-crafted features from nearly 1400 lung CT images to train a variety of classifiers based on them. In the first experiment, in total 424 Radiomics features per image has been used to train classifiers such as: Random Forest (RF), Support Vector Machine (SVM), Decision Tree (DT), Naive Bayes (NB), Linear Discriminant Analysis (LDA) and Multi-Layer Perceptron (MLP). In the second experiment, we evaluate each feature category separately with our classifiers. The third experiment includes wrapper feature selection methods (Forward/Backward/Recursive) and filter-based feature selection methods (Fisher score, Gini Index and Mutual information). They have been implemented to find the most relevant feature set in model construction. Performance of each learning method has been evaluated by accuracy score, wherewe achieved the highest accuracy of 78% with Random Forest classifier (74% in 5-fold average) and 0.82 Area Under the Receiver Operating Characteristics (AUROC) curve. After RF, NB and MLP showed the best average accuracy of 71.4% and 71% respectively.

  • Nicolle, Mathias
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Rymdteknik.
    Mechanical and structural conceptof the ISS microgravity experimentpayload: AtmoFlow2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This Master Thesis report presents the mechanical concept and design of a microgravity fluid science experiment that is planned to be launched to the International Space Station in approximately five years. Named AtmoFlow, this experiment aims to study the complex flow phenomena occurring in different planets’ atmosphere by implementing a scaled-down model of a planet-atmosphere system in microgravity. The design introduced here focuses on several of the experiment’s systems: the Turn Table, a rotating system involving a Fluid Cell Assembly, a Thermal Control System and two Rotation Drive Systems. Design methods, main choices and crucial conception steps are presented. Components’ dimensioning and choices are motivated. Models and analyses are derived from the selected design to ensure that the design meets the requirements on microgravity disturbances, structural and rotational characteristics stated during previous project’s phases. The Computer Assisted Design model of the experiment’s final concept and its integration sequence are eventually proposed and discussed.

  • Wanner, Svenja
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner.
    Systematic approach on conducting fatigue testing of unidirectional continuous carbon fibre composites2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    High fuel saving potentials, increased load carrying capacities and therefore competitive advantages force the heavy goods vehicle industry to enhance the efforts towards comprehensive lightweight designs. Facing this challenge, the material evaluation in terms of simulations and physical testing of composite materials is required for the design against fatigue failure due to road introduced vibrations. Eliminating fatigue testing issues in order to gain acceptable and reproducible results, a future-oriented systematic approach on conducting constant amplitude tension-tension fatigue testing on a unidirectional composite material is presented. Following the material characterisation of the carbon/epoxy material in terms of tensile and shear properties as well as fibre volume fraction, several combinations of tab configurations and specimen geometries have been tested with regard to their suitability for fatigue testing. Finally, the unidirectional material was successfully tested under tension-tension fatigue and first elaborated test data were assessed. In conclusion, the usage of straight aluminium tabs completely clamped inside the grips and bonded to the straight-sided specimen with 3M DP420 adhesive, using ventilation during the test is the recommended test procedure.

  • Shwan Kurdi, Mir
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Nonlinear Attitude Control ofa Generic Aircraft2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Determining suitable controllers for the process of evaluating dynamic per-formance of multiple versions of an aircraft’s aerodynamical, geometric and propulsive properties in its conceptual stage is an expensive task.In this report a proposition is made to utilize a generalized feedback lin-earizing controller that o˙ers the aircraft designer valuable insight into the manoeuvre performance of their aircraft. This is carried out by first estab-lishing fundamental requirements for a controller capable of treating a generic airframe, and formulating the resulting control laws.It is shown in this report, that with a suÿciently simple aerodynamic and propulsive model explicit feedback linearization is possible with satisfactory performance and robustness. Whereas it would be necessary to implement INDI if explicit inverse mappings are not obtainable. Which in turn would introduce additional tuning parameters.Robustness verification is performed in two stages, firstly by introducing a high model uncertainty within the flight control system and showing, via simulation, that the control system successfully performs desired multi-axial manoeuvres whilst managing to maintain the induced side slip below 0.1◦. Secondly by disturbing the aircraft with a discrete side slip. Critical side slip disturbance angle was found to be considerably larger than that for regular aircraft entailing that the used case study may be somewhat over dimensioned with respect to yaw control authority.

  • Philippe, Alexis
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Optimisation of an aeronautic production line through the managementof tools and the shortage of items2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis work is part of a process to ensure the production ramp-up of the A320neo aircraft pylons at Airbus Saint-Eloi factory (Toulouse). The aim of the project was to optimise the production management in order to sustain the transition to a serial production of the assembly lines. The objective of the thesis work was to develop a model to prevent the downtime of the production lines caused by the shortage of the assembly lines or the unavailability of tools on workstations.Firstly, the work investigates the existing models in order to understand the causes of stocks variability. Performance of tools was determined with the Markov chain model. Then, the work provides a method to forecast production needs in terms of items and tools. An algorithm was developed to collect and process the data on the existing resources in order to compare it to the forecasted needs. Solutions were designed to identify the causes of the shortages on the production lines. In addition, by analysing the trends of the shortage of stocks and the availability of tools on workstation, a forecast of long term constraints for production is possible. The method showed promising results to identify and manage the missing items and tooling on the workstations.

  • Lejon, Alexander
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Creation and Validation of Early Stage Conceptual Design Methodology for Blended WingBody Aircraft2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The current design paradigm for developing tube-and-wing style aircraft has been well documented in literature. This research attempts to develop and val-idate a similar design methodology to what is presently utilized for tube-and-wing based aircraft, but has so far not been successfully implemented for the blended wing-body. This construction has no clear distinction between the lift generating surfaces and the cargo carrying structure. The methodology that was developed included the concatenation and validation of low-fidelity, low speed and low complexity aerodynamic models in order to allow for quick and simple analysis of a large number of possible geometries. This enables the user eÿciently determine the most promising candidate geometries for further study and/or development. Known issues with the low velocity and low com-plexity aerodynamic models include the absence of shock wave modelling, an important part in determining the aerodynamic performance of a lift generat-ing surface. The result of this work is the creation and documentation of a procedure for early-stage design of a blended wing-body airframe. However, due to convergence issues with the high-fidelity CFD solver, the methodology could not been validated for transonic flow. It can thus be only considered valid for flow velocities for which the Prandtl-Glauert correction is valid.

  • Lagemann, Benjamin
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Marina system.
    Efficient seakeeping performance predictions with CFD2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    With steadily increasing computational power, computational fluid dynamics (CFD) can be applied to unsteady problems such as seakeeping simulations. Therefore, a good balance between accuracy and computational speed is required. This thesis investigates the application of CFD to seakeeping performance predictions and aims to propose a best-practice procedure for efficient seakeeping simulations.

    The widely used KVLCC2 research vessel serves as a test case for this thesis and FINEŠ/Marine software package is used for CFD computations. In order to validate the simulations, results are compared to recent experimental data from SSPA as well as predictions with potential ˛ow code SHIPFLOW® Motions.

    As for the calm water simulations, both inviscid and viscous ˛ow computations are performed in combination with three mesh refinement levels.

    Seakeeping simulations with regular head waves of different wavelengths are set-up correspondingly. Furthermore, different strategies for time discretization are investigated. With the given computational resources, it is not feasible to complete seakeeping simulations with a ˝ne mesh. However, already the coarse meshes give good agreement to experiments and SHIPFLOW® Motions' predictions. Viscous ˛ow simulations turn out to be more robust than Euler ˛ow computations and thus should be preferred. Regarding the time discretization, a fixed time discretization of 150 steps per wave period has shown the best balance between accuracy and speed. Based on these findings, a best-practice procedure for seakeeping performance predictions in FINEŠ/Marine is established.

    Taking the most efficient settings obtained from head wave simulations, the vessel is subjected to oblique waves with 160° encounter angle. Under similar wave conditions, CFD predictions of a similar thesis show close agreement in terms of added wave resistance. Compared to the previous head wave conditions of this study, added resistance in 160° oblique waves is found to be significantly higher. This underlines that oblique bow quartering waves represent a relevant case for determining the maximum required power of a ship.

    CFD and potential ˛ow show similar accuracy with respect to ship motions and added wave resistance, albeit potential ˛ow outperforms CFD in terms of computational speed. Hence, CFD should be applied in cases where viscous effects are known to have large influence on a vessel's seakeeping behavior. This can be the case if motion control and damping devices are to be evaluated, for instance.

  • Kjelldorff, Maria
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Marina system.
    Water Current Measurements using Oceanographic Bottom LanderLoTUS?2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    oTUS is a Long Term Underwater Sensing, bottom landing, node for observations of ocean water temperatures. LoTUS measures temperature (moored to the seafloor) according to a spec-ified time schedule until, at the end of the mission, it surfaces to transmit the collected data to on shore recipients using an Iridium link. The paper presents an extension of the sensing capability to include water current velocity (speed and direction) using a robust, reliable and inexpensive Eulerian method. The method is based on the "tilting stick" principle where a combination of inertia measurement data and magnetic sensor data is used. The paper discusses the principal technique, the modeling of the system, practical considerations, and optimization of the setup for specific flow conditions along with verifying experimental data.

  • Janson, Rebecca
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    A simplified model for the design of floor structures with vibrating sources for architectural applications2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    When designing a building, sound is one of the problems to take into account. Vibrating machines, such as ventilation fans, water pumps and compressors, generate structure-borne sound. The structure-borne sound travels up the structure of the building and generates sound in adjacent rooms. To be able to predict the sound radiated in the adjacent rooms when designing a building, a semi-analytical model has been developed. Using the incident vibrations from the floor plate where the vibrating machine is standing, the transmission loss in the junction between the floor plates and the wall plate is calculated. This can bed one in every junction in the building, creating a system of multiple junctions. The sound radiation to the adjacent rooms is later approximated using the velocity of the plates.The model is verified with measurements in two case studies. This shows that the model has good potential in predicting the normal acceleration amplitudes in the relevant plates. The two case studies have different geometric properties and different sources. The comparison between the model and the measurement gives similar results. The model analyses the output of the bending waves since this is the wave type that radiates sound, but longitudinal waves are present in the model. With only two case studies it is too early to say that the model works for all systems, but it could be used as a fist approach. The model, right now, is restricted to isotropic, homogeneous material without losses. A parametric study shows that the transmission loss is dependent on the ratio between the thicknesses of the floor plate and the wall plate. The ratio should be as large as possible to get a high transmission loss, but depends on how the junction is structured.

  • Falquier, Rene
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Longitudinal Flight Mechanics of Paraglider Systems2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This project outlines a cost-effective numerical simulation method for the analysis of the longitudinal mechanics of paraglider systems. It is built on static stability methods for the analyses of low subsonic aircraft, non-linear lifting line methods for aerodynamic parameterization, and frequency domain analysis methods derived from system theory. Paragliders possess a glide polar in the range of ≈ 25-60 km.h−1 and display underdamped dynamic responses dominated by a long-period mode. The simulation results for performance and dynamic response are qualitatively valid relative to experimental data and in the same order of magnitude.

  • Ask, Jacob
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Rymdteknik.
    Selected Trends and Space Technologies Expected to Shape the Next Decade of SSC Services2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Since the early 2000s the space industry has undergone significant changes such as the advent of reusable launch vehicles and an increase of commercial opportunities. This new space age is characterized by a dynamic entrepreneurial climate, lowered barriers to access space and the emergence of new markets. New business models are being developed by many actors and the merging of space and other sectors continues, facilitating innovative and disruptive opportunities. Already established companies are adapting in various ways as efforts to stay relevant are gaining attention. The previous pace of development that was exclusively determined by governmental programs are now largely set by private and commercial ventures. Relating to all trends, new technologies and driving forces in the space industry is no trivial matter. By analyzing and examining identified trends and technologies the author has attempted to discern those that will have a significant impact on the industrial environment during the next decade. Market assessments have been summarized and interviews have been carried out. Discussions and conclusions relating to the services provided by the Swedish Space Corporation are presented. This report is intended to update the reader on the current status of the space industry, introduce concepts and provide relevant commentary on many important trends.

  • Brenes Brenes, Rebeca
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Hydropower Modelling of Continental Europe Using EMPS2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Flexible hydropower plays a vital role when integrating large shares of variablerenewable generation in the power system. This project proposes a method forcreating a stochastic model for hydropower in Continental Europe using EMPS, apower market simulator software that specialises on hydrothermal power systems.The model is intended to be used in a power market analysis context, to assess thehydropower behaviour in Continental Europe in the medium and long term.The first step to create the model was to gather data from multiple sources regardinghydropower stations and reservoirs located in Continental Europe. The gathereddata was built and unified into a geographical information system to provide visualanalysis and facilitate performing of different operations and algorithms. Thecountries under study were split into different areas depending on the water basinsand other location factors. Representative inflow series were created for each area,and these were fed directly into EMPS. The stations and reservoirs were aggregatedper area and the inputs required by EMPS were calculated using a model based onhistorical data and an optimisation process.The model provides results for 45 different weather scenarios. The hydropowergeneration and reservoir content for each country were validated using historicaldata. In general, the results obtained provide a satisfactory representation of thehydropower in the region under study. Fine tuning is still required to improve theresults, but this project successfully provides a solid method to create the core ofthe stochastic hydropower model of Continental Europe in EMPS.

  • Barra, Stefano
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Functional Testing of the Electrical Power System of the MIST Satellite2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The Electrical Power System is the key subsystem for the survival of the satellite.It not only supplies power to the satellite by keeping the battery adequatelycharged, but it also provides crucial fault detection and recovery functions.The target of this thesis work is to characterize and test all the functionalitiesof the EPS of the MIST satellite in realistic operational conditions through theimplementation of hardware and software simulators. Such a comprehensiveframework is based on a MATLAB software, the MIST flight hardware, aswell as Solar Panel Simulators and Arduino-based dummy loads created byprevious students in the project. These tools are used to integrate all theseelements into an easy-to-use simulation environment that very closely mimicsconditions in actual orbital flight and that can be used as a model for suchsimulations in similar satellite projects. The purpose of the simulations in thisenvironment is to verify that the planned flight profile of the satellite is correctand safe, especially from a power subsystem point of view.

  • Tamadon, Nahal
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Utilizing Privately Owned Flexibilities in the German Distribution System: Technical and Regulatory Framework2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This Master’s thesis project aims to define the technical and regulatory framework of asystem flexibility service utilizing distributed flexibilities connected to the low-voltage (LV)level. The flexibility service outlined here is local balancing, with the purpose of increasing theload-generation balance in LV networks using thermostatically controlled loads and ElectricalEnergy Storage (EES) devices. The thesis is performed at Avacon Netz GmbH, a GermanDSO, as part of the German demo for project InterFlex.The first part of the thesis encompasses the technical framework of local balancing. For thispurpose, day-ahead scheduling algorithms for heat pumps and EES devices are proposed toincrease the local consumption of distributed generation, and thereby decrease the reversepower flow and load peaks. Two scheduling algorithms are proposed in this thesis, one basedon numerical methods and one on optimization. The proposed algorithms are simulated fornine LV-networks in Avacon Netz’ grid area. The simulation results show that by utilizing allthe residential heat pumps and EES devices, the load peaks and the peak reverse flow can bereduced by up to 21.30% and 37.30% respectively.The commercial and regulatory framework of local balancing are analyzed in the second part ofthe thesis. The said service can be traded either using market-based mechanisms, or throughbilateral contracts between the DSO and the flexibility providers. Utilization of distributedflexibilities through the DSO has been vaguely mentioned in the German Energy Industry Act.The contractual framework and level of load interference has yet to be explicitly defined. Themarket-based trading is also analyzed in Part II, proposing a local semi-competitive marketfor flexibility services. Unlike flexibility services such as voltage or frequency control, localbalancing does not require a high level of DSO-TSO coordination. The service optimizesnetwork-capacity allocation, and makes room for additional integration of renewable-basedgeneration.

  • Ariza Rocha, Oscar David
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknisk teori och konstruktion.
    Dynamic transformers rating for expansion of expansion of existing wind farms2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Distribution system operators face the challenge to connect users rapidly to the grid and the opportunity to reduce costs for new connections. A method to enhance network operation and planning is dynamic transformer rating (DTR), which considers load and temperature variations to increase the rating of the transformer while maintaining in safe operation.

    This project investigates DTR application to an existing population of transformers connected to a wind park and proposes a method for adding new turbines to the grid using installed transformers. Five transformer locations and nine units belonging to E.ON AB are used to find the potential of DTR for network expansion.

    A weather analysis reveals that simultaneous high wind speeds and high temperatures seldom occur. An aging estimation based on the IEC 60076-7 standard shows that the transformers for wind power applications are underused. Considering the transformer thermal model, a sensitivity analysis shows that the parameters that mostly affect the aging rate are the moisture content, the hot spot factor, and the top-oil temperature rise. The maximum load to assure aging below 50 years is calculated for each transformer for different maximum hot-spot temperature levels showing that increasing the maximum allowed temperature reduces curtailment and increases aging. A single node analysis depicts the optimal expansion of wind power from a generator perspective, and a network analysis introduces further restrictions to the network. As a result, the optimal increase factor is around 30 to 50 % and is larger for higher hot-spot temperature limits.

    Accurate weather measurements and transformer parameters are necessary to make a proper estimation of transformer aging to unlock transformer potential. To use fiber optic temperature sensors in new transformers and on-site temperature measurements can increase the rating of the transformer. A maximum allowed temperature of 110◦C is conservative and limits the potential of the transformer for wind power applications. Finally, society benefits from DTR in wind power applications because there is a more efficient use of resources and additional renewable energy can be introduced to the network.

  • Ryan, Christian
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    On Optimization of Sequential Decision-Making in Customer Relationship Management using Deep Reinforcement Learning2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Customer relationship management (CRM) is a fickle but pivotal elementto the success of any business. Used correctly, it can not only yield higherrevenue and lower operational costs, but significantly boost customersatisfaction. Nonetheless, it can also be mismanaged—sacrificing thewell-being of customers for profitability. Industries have thereby beenflooded with a range of different heuristic strategies that aim to optimizeCRM. This thesis aims to instead study and optimize CRM using a datadrivenapproach, and present a framework that can readily incorporatecustomer well-being into the optimization process. More specifically: cana strategy that outperforms a business’ current strategy without any realworldimplications be derived using modern advances in reinforcementlearning? In this context, the lifetime value (LTV), i.e. net profit, of acustomer will be used as the objective function to optimize for.Using deep feed-forward neural networks, an artificial environmentmimicking typical customer behavior was attained. The model’s predictivecapabilities deviated merely a couple of percent from the true averagecustomer behavior seen in the data. This was further leveraged byan algorithm to obtain a business strategy through reinforcement learning.This novel algorithm is based on deep Q-networks, with furtherdomain-specific additions such as combined experience replay and doublelearning. The algorithmically derived business strategy theoreticallyoutperformed the current state-of-the-art business strategy by approximately100 percent in average 2-year LTV, and further outperformed aplethora of different business strategies.

  • Micski, Erik
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    CO2 Flow Estimation using Sidestream Capnography and Patient Flow in Anaesthesia Delivery Systems2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Volumetric CO2 data from patients in anaesthesia delivery systems are sought after by physicians. The CO2 data obtained with the commonly used sidestream sampling technique are not considered adequate for volumetric CO2 estimation due to distortion and desynchrony with patient flow. The purpose of this thesis was to explore the possibility of using signal enhancing methods to the sidestream data to accurately estimate CO2 flow using a Flow-i anaesthesia delivery system.

    To evaluate sidestream performance, experimental data was acquired using a mainstream and a sidestream capnograph connected in series to a FRC test lung with known CO2 content, ventilated by a Flow-i anaesthesia machine. The data was then enhanced and analysed using signal processing methods including sigmoid modelling and neural networks.

    A Feed Forward Neural Network achieved results closest resembling the mainstream capnogram of the evaluated signal processing methods. The mainstream capnogram, considered the benchmark, produced large internal scattering and approximately 25 % offset from actual CO2 flow while using the inherent patient flow data produced by the Flow-i anaesthesia system. When using patient flow data from a Servo-i ventilator, the resulting CO2 flow estimates were drastically improved, producing estimates within 10 % error.

    This thesis concludes that there are several potential processing methods of the sidestream data to approximate the mainstream signal, however the patient flow of the Flow-i system are a suspected source of error in the CO2 flow estimation.

  • Man, Hengyu
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Efficient Intra Prediction for the Next-Generation Video Compression Standard2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    VVC (Versatile Video Coding) is a next-generation video compression standard.It is a potential successor to the MPEG-4/H.264 and High EfficiencyVideo Coding (HEVC)/H.265. Its first working draft was released in April2018 by MPEG and VCEG joint video exploration team. Its final standard isto be approved before the end of 2020. Video compression enables more efficientuse of transmission and storage raw video data to meet the increase ofdemand for high quality video over the internet.The objective of this thesis work is to research and implement algorithmsdeveloped at Ericsson Research to improve video coding efficiency. The algorithmis about intra angular prediction. The intra angular prediction usesprevious decoded samples of the current picture to predict the current block.In HEVC there are 35 directional intra prediction modes designed to be ableto efficiently model different directional structures typically present in videoand image contents. In VVC, the total number of directional intra predictionmodes increases to 67. This thesis work is to research a dynamic granularityintra angular prediction algorithm. The thesis work has investigated severalvariants of dynamic granularity intra angular prediction and focused on improvingvideo coding efficiency.

  • Ter Vehn, Anton
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Longitudinal Control Design for Autonomous HDVs2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Autonomous vehicles are evolving from a futuristic dream to current realityas technology becomes more and more mature. However, their presence on thehighways will demands precise control over lateral and longitudinal positioning.This thesis, completed at Scania Group AB in Södertälje, mainly focuses on thedesign of longitudinal controllers for trajectory tracking without compromisingalready mature control solutions. To this end, a virtual vehicle is created toextrapolate where the vehicle is supposed to be in time, and its position andvelocity are used as reference inputs. Then, two different control strategies (aPD controller and a lead compensator) based on position error and velocityerror are developed. A breaking algorithm is also developed to use servicebrakes on an Heavy-duty vehicle effectively. Numerical studies highlight thatthe proposed controllers exhibit excellent performance while tracking both positionand velocity trajectories. The proposed controllers are examined in threedifferent test cases: varying velocity, executing lane changes, and driving in anenvironment with significant changes in topology. In all test cases, the positionerror is less than 1m, while the velocity error is less than 0.5m/s. Comparedto the existing controller, developed in Scania Group AB, these controllers improvethe tracking performance significantly. Also, both controllers improverobustness against lateral changes and exogenous forces.

  • Székely, Éva
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Tal, musik och hörsel, TMH.
    Henter, Gustav Eje
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Tal, musik och hörsel, TMH.
    Beskow, Jonas
    KTH, Tidigare Institutioner (före 2005), Tal, musik och hörsel.
    Gustafson, Joakim
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Tal, musik och hörsel, TMH.
    How to train your fillers: uh and um in spontaneous speech synthesis2019Konferansepaper (Fagfellevurdert)
  • Betz, Simon
    et al.
    Zarrieß, Sina
    Székely, Éva
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Tal, musik och hörsel, TMH.
    Wagner, Petra
    The greennn tree - lengthening position influences uncertainty perception2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Synthetic speech can be used to express uncertainty in dialogue systems by means of hesitation. If a phrase like “Next to the green tree” is uttered in a hesitant way, that is, containing lengthening, silences, and fillers, the listener can infer that the speaker is not certain about the concepts referred to. However, we do not know anything about the referential domain of the uncertainty; if only a particular word in this sentence would be uttered hesitantly, e.g. “the greee:n tree”, the listener could infer that the uncertainty refers to the color in the statement, but not to the object. In this study, we show that the domain of the uncertainty is controllable. We conducted an experiment in which color words in sentences like “search for the green tree” were lengthened in two different positions: word onsets or final consonants, and participants were asked to rate the uncertainty regarding color and object. The results show that initial lengthening is predominantly associated with uncertainty about the word itself, whereas final lengthening is primarily associated with the following object. These findings enable dialogue system developers to finely control the attitudinal display of uncertainty, adding nuances beyond the lexical content to message delivery.

  • Székely, Éva
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Tal, musik och hörsel, TMH.
    Henter, Gustav Eje
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Tal, musik och hörsel, TMH.
    Beskow, Jonas
    KTH, Tidigare Institutioner (före 2005), Tal, musik och hörsel.
    Gustafson, Joakim
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Tal, musik och hörsel, TMH.
    Off the cuff: Exploring extemporaneous speech delivery with TTS2019Konferansepaper (Fagfellevurdert)
  • Székely, Éva
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Tal, musik och hörsel, TMH.
    Henter, Gustav Eje
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Tal, musik och hörsel, TMH.
    Beskow, Jonas
    KTH, Tidigare Institutioner (före 2005), Tal, musik och hörsel.
    Gustafson, Joakim
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Tal, musik och hörsel, TMH.
    Spontaneous conversational speech synthesis from found data2019Konferansepaper (Fagfellevurdert)
  • Székely, Éva
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Tal, musik och hörsel, TMH.
    Wagner, Petra
    KTH.
    Gustafson, Joakim
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Tal, musik och hörsel, TMH.
    THE WRYLIE-BOARD: MAPPING ACOUSTIC SPACE OF EXPRESSIVE FEEDBACK TO ATTITUDE MARKERS2018Inngår i: Proc. IEEE Spoken Language Technology conference, 2018Konferansepaper (Fagfellevurdert)
  • Sadik, Bala
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Fastigheter och byggande.
    Elias, Sanar
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Fastigheter och byggande.
    Svenska byggföretags ställning till Agenda 2030: En analys av Sveriges tio största byggföretag kring hållbarhetsarbete och mål2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Detta examensarbete avhandlar hållbarhetsprojekten och målsättningar av Sveriges 10 största byggföretag samt deras ställningstaganden gentemot Agenda 2030. Faktum att begreppet hållbarhet kan uppfattas och definieras på olika sätt har skapat en viss otydlighet i världen kring begreppet. De största byggföretagen i Sverige presenterar en hållbarhetsredovisning som redogör för de framgångsrika hållbarhetsprojekten inom verksamheten samt företagets framtida planer. Byggföretagens tillvägagångssätt i deras arbete för att uppnå målen i Agenda 2030 är i stort sätt densamma, med undantag för vissa bolag som har unik taktik. Flera av de utvalda byggföretagen har även antalet mål uppsatta som sträcker sig längre fram än år 2030; vilket delvis beror på regeringens klimatlag för att uppnå ett klimatneutralt Sverige år 2045. I denna studie har fyra mål från Agenda 2030 blivit utvalda för granskning; sedan har byggföretagens hållbarhetsredovisningar undersökts i syfte att utläsa företagens ställningstaganden i förhållande till målen. Teorin om svag och stark hållbarhet tillämpad i en organisation har applicerats på respektive byggföretags hållbarhet vilket resulterade i ett tydligt mönster. Resultaten pekar mot att styrkan av hållbarhet i ett företag beror på dess omsättning, vilket var relativt klart eftersom hållbarhetsredovisningarna hos de företag som hade större omsättning var mer omfattande samtidigt som målsättningen var mer preciserad och antalet hållbarhetsprojekt högre. Härvid bör nämnas att signaleringsteorin till viss del motsäger antagandet om att hållbarhetsstyrkan av ett företag är beroende på dess omsättning. Signaleringsteorin menar att företag kan öka sitt värde och popularitet via frivillig redovisning samt betoning och upplyftning av de ’finare’ delarna ur verksamheten. Framtida studier kan finna denna studie som hjälpsam för bedrivandet av forskning inom samma fält. Ytterligare fördjupande rapporter inom samma område kan framtas med denna studie som grund, vilket möjligtvis kan ljusna förutsättningarna av djupdykande hållbarhetsresearch av alla typer av företag, bygg- eller inte. Hållbarhetsarbete är ett relevant ämne i världen just nu, varför ytterligare studier av denna karaktär fordras i syfte att uppnå en bättre förståelse för hållbarhetskonceptet och utvecklingen av effektiva strategier för en ännu mer hållbar värld

  • Wisseng, Sara
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Fastigheter och byggande.
    Ölund, Linnea
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Fastigheter och byggande.
    Coworking och dess påverkan vid värdering av kommersiella fastigheter2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Det allt mer digitaliserade, globala och ständigt uppkopplade samhället har gjort att branscher ocharbetsplatser förändras. Inom fastighetsbranschen har coworking blivit ett allt mer känt fenomen ochtar över allt större andel av den totala kontorsmarknaden. Genom coworking ersätts traditionellakontorshyreskontrakt med medlemskap och företag får tillgång till flexibla kontorslösningar medmöjlighet till nätverkande och tjänster i form av allt från skrivare och konferensrum till öltapp ochsociala events. Coworking innebär korta medlemskap istället för långa fasta hyreskontrakt förmedlemmar vilket har fått stor genomslagskraft bland stora som små företag runt om i världen.Tidigare studier i USA tyder på att coworking över en viss andel av en fastighet innebär en högredirektavkastning. Studiens syfte är att identifiera detta samband och undersöka om och i så fall vilkenpåverkan coworking har vid värdering av kommersiella fastigheter i praktiken i Sverige. Utöver dettasyftar studien till att undersöka vad värderare behöver ta hänsyn till vid en värdering av en fastighetsom innefattar coworking. Studien grundas på teori som behandlar värderingsmodeller, osäkerhet ochrisk i samband med värdering samt marknadsanalys. För att besvara studiens frågeställningar harfastighetsvärderare från fem olika väletablerade fastighetsrådgivningsföretag i Stockholms CBDområdevalts ut och intervjuats.Resultatet indikerar på att det finns ett liknande samband mellan andelen coworking i en fastighet ochdirektavkastningen även i Sverige. Ett exakt samband går dock inte att påvisa på grund av avsaknad avrenodlade coworkingfastigheter på den svenska marknaden. Beroende på hur marknaden förcoworking kommer att utvecklas kommer fastighetsvärderare i allt större utsträckning behöva tahänsyn till den risk som coworking över en viss andel av en fastighet medför vid värdering avkommersiella fastigheter.

  • Engblom, Anna
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Fastigheter och byggande.
    Isacsson, August
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Fastigheter och byggande.
    Poverty reduction through land titling: A study about the economic effects of the Malawi national land policy2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Access to land is vital for providing our basic needs. According to earlier research, private landtitles are a prerequisite for secure land rights and are vital for enabling sustainable economicgrowth and poverty reduction. In Malawi, where a majority of the land is customary, newlaws have been enacted, but not yet implemented. The new laws allow registration ofcustomary land into private land, i.e. land titling. This bachelor thesis investigates the possibleeconomic effects of land titling in Malawi based on earlier research and on the views ofMalawian stakeholders. It was found that the World Bank states that land titling will lead toincreased investments and improved productivity; increased credits access with lowerinterest rate; increased liquidity on transaction markets; increased access to rental market;increased mobility; increased gender equality and decentralization of power. Even though thecultural practices in Malawi partly collide with the privatization of customary land, thestakeholders generally agree with the effects described by the World Bank. It is difficult topredict the effects of the new laws as it depends on various factors. However, land titling willsurely lead to increased tenure security, which inherently is valuable for the landowners.

  • Gustafsson, Markus
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Fastigheter och byggande.
    Wåhlin, Johannes
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Fastigheter och byggande.
    Hållbar finansiering: Fastighetsbolagens utformning av gröna obligationer2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Den svenska marknaden för gröna obligationer har ökat explosionsartat de senaste åren. Det är därför häpnadsväckande att det ännu inte finns en vedertagen definition kring vad som menas med ordet grön och att ett regelverk för vad som krävs för att få emittera en obligation som grön saknas. Följaktligen kan investerare dra sig från att investera i gröna obligationer, då tydliga garantier saknas. Omvänt blir det svårt för fastighetsbolag att resa grönt kapital, då det är otydligt vilka krav som ställs i gengäld. Studiens syfte är därför att reda ut de frågetecken som råder på den gröna obligationsmarknaden, genom att studera de emitterande fastighetsbolagens tolkning av gröna obligationer och vad fastighetsbolagen är beredda att utlova i gengäld mot grönt kapital. Förhoppningen är att studien ska kunna öka transparensen på marknaden och skapa diskussionsmaterial för ett framtida regelverk, med frågeställningen; Hur har fastighetsbolagen utformat sina gröna obligationer på den svenska obligationsmarknaden? Studien grundas på teorier, begrepp och modeller kring fastighetsekonomi, obligationer, miljöcertifieringar och CSR. Med hjälp av en induktiv kvalitativ metod sammanställs sedan de miljöcertifieringar som utlovas i obligationsprospekten från de redan emitterade obligationerna på Nasdaq OMX Stockholm Nordics lista över hållbara obligationer. Resultatet visar på att BREEAM Very Good, Miljöbyggnad Silver och LEED Guld är de tre mest frekventa miljöcertifieringarna. Det finns dock stora skillnader mellan gröna obligationer emitterade av statliga fastighetsbolag kontra privata fastighetsbolag, där de statliga fastighetsbolagen tenderar att emittera en liten andel gröna obligationer men till höga nivåer av miljöcertifieringar, medan privata fastighetsbolag tenderar att emittera en stor andel gröna obligationer men till låga nivåer av miljöcertifieringar. Detta tyder på en inkonsekvent och icke transparent marknad som underminerar konceptet med gröna obligationer. Slutsatsen är således att en tydlig definition av vad som avses med en grön obligation krävs.

  • Lindqvist, Richard
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Fastigheter och byggande.
    Värdering av kommersiella fastigheter baserat på ortsanalys: Fastighetsägare bör ha ett geografiskt diversifierat bestånd2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Starka fundamentala förhållanden i kapitalmarknaden har bidragit till att driva upp priserna på fastigheter i allmänhet och inom de geografiska områden där institutionella och internationella aktörer investerar i synnerhet.Detta arbete jämför olika geografiska kontorsmarknader från ett investerarperspektiv, med syfte att kartlägga i vilken typ av geografiskt läge direktägda fastigheter ger starkast risk-justerad avkastning för en långsiktig investerare. Delvis genom att kartlägga marknadernas (städernas bästa geografiska läge för kontor) historiska tillväxt för att kunna kategorisera dem som primära eller sekundära marknader, men framför allt genom att utvärdera rådande direktavkastningskrav på respektive studerad marknad.Efter redogörelse över centrala begrepp och essentiella parametrar inom ämnet adresseras riskmåttet volatilitet som ett möjligt argument till varför fastigheter i så kallade sekundära lägen bör anses ha lägre risk än vad marknaden uttrycker i form av direktavkastningskrav. Med framlagda argument presenteras därefter två alternativa modeller för att fastställa direktavkastningskrav på olika geografiska marknader. Arbetet avslutas med en förenklad tillämpning av modellerna på två stora fastighetsbestånd av olika karaktär; Hufvudstaden vars fastigheter uteslutande är belägna på primära marknader, och Klövern, vars bestånd i Sverige är spritt över 12 orter men i starka lägen på respektive ort.Till studierna inhämtades data från IPD, Datscha, Nordanö och PwC. Insamlad data underbygger tesen att hyresnivåer på fastigheter i primära lägen drabbas hårdast av globala kriser och generellt är mer volatila än i sekundära lägen. Vid förenklad tillämpning av presenterade modeller kunde även konstateras att ett diversifierat bestånd ger bättre risk-justerad avkastning över tid vilket även går i linje med portföljteori och faktumet att marknadsrisken förblir densamma oberoende av hur många tillgångar som ingår i en portfölj.Utifrån detta arbete kan det även argumenteras för att en optimal fastighetsportfölj bör vara överviktad mot fastigheter i sekundära lägen sett till aktuella värderingar.

  • Johansson, Måns
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Fastigheter och byggande.
    Strömberg, Malin
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Fastigheter och byggande.
    Coworking – När är det fördelaktigt?: En jämförelse mellan coworking och traditionella kontor2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Under senare år har efterfrågan på flexibla avtal ökat på den svenska kontorsmarknaden, vilket har banat väg för ett nytt kontorskoncept - coworking. Konceptet, som är snarlikt kontorshotell, bygger på filosofin om att kapitalvaror och tjänster ska delas mellan parter. I och med konceptets relativt korta historia på svensk kontorsmarknad finns en avsaknad av studier baserade på hyresgästens perspektiv. Uppsatsen använder sig av en kvalitativ forskningsmetod, där sju semistrukturerade har genomförts för att besvara den huvudsakliga frågeställningen: När är det mer fördelaktigt för hyresgästen att välja coworking?En uthyrning av ett traditionellt kontor regleras av hyreslagen, det vill säga kapitel 12 Jordabalken. Dessa typer av hyresavtal är ofta inte tillräckligt flexibla för vissa företag, då dessa kontrakt oftast har en kontraktslängd på minst tre år, samt en viss uppsägningstid. Coworking är ett koncept som försöker finna en lösning för de företag som inte kan skriva så länga kontrakt.Uppsatsen visar att det kan vara fördelaktigt för mindre företag som befinner sig i en expansiv fas att välja coworking framför traditionellt kontor. Det beror främst på flexibiliteten som efterfrågas när expansiva företag har svårigheter att förutse framtida lokalbehov. Konceptet kan också vara attraktivt när allt fler branscher går mot en konsultliknande verksamhet, där mindre tid spenderas på kontoret. Det kan vara hållbart både ekonomiskt och ekologiskt för mindre företag att välja coworking då konceptet bygger på filosofin om att kapitalvaror och tjänster ska delas mellan parter och kapitalsvaga företag kan därför reducera sina utgifter bundet till detta. Vidare finns det vissa utmaningar med coworking, exempelvis är flera juridiska frågor i en gråzon eller att vissa verksamheter som arbetar med strikt sekretess inte kan använda sig av coworking.

  • Disputas: 2019-11-07 10:00 Kollegiesalen, Stockholm
    Stigsson, Martin
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Structural Uncertainties of Rock Fractures and their Effect on Flow and Tracer Transport2019Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [sv]

    Att förstå flöde och transport av lösta ämnen genom sprickorna i berggrunden är viktigt för den långsiktiga säkerheten av ett geologiskt slutförvar av farligt avfall. I en diskret spricknätverksmodell byggs flödesvägarna upp av kedjor av flödesvägar genom de enskilda sprickorna i bergmassan. Varje sådan flödesväg genom varje spricka bidrar således till bergmassans totala flödes- och transportegenskaper. Därmed är kunskap om flödes- och transportegenskaper för de enskilda sprickorna viktiga för att kunna utföra en säkerhetsanalys av ett geologiskt slutförvar av farligt avfall.Hålrummet som utgör en spricka beror av de begränsande ytornas råhet tillsammans med den normalspänning som verkar på sprickan. Därmed är uppskattningen av hålrummet beroende av noggranna mätningar av sprickans orientering i förhållande till omgivande spänningsfält samt råheten på begränsningsytorna. Eftersom alla mätningar är behäftade med osäkerheter, såsom osäkerheter i verktyg, yttre störningar och mänskliga faktorer, kommer de tolkade egenskaperna inte att beskrivas av enskilda deterministiska värden utan av sannolikhetsfördelningar. Beroende på kombinationen av använda värden från dessa fördelningar kommer flödes- och transportegenskaperna för sprickorna att variera.Syftet med denna avhandling är därför att presentera en metod att beskriva det geometriska ramverket för sprickor i kristallint berg, inklusive osäkerheter, samt att undersöka hur dessa kan påverka tolkningen av flödes- och transportegenskaper för grundvatten och lösta ämnen. Genom att beräkna sprickornas orientering och osäkerhet från sprickornas skärning med borrhål, kan ett utfallsrum för orienteringsosäkerheten beräknas. Denna osäkerhet i orientering kommer således, under antagande av ett fixt spänningstillstånd, att resultera i en fördelning av normalspänningar som kan verka på sprickan och därmed hur hoptryckt sprickan är. Råheten på sprickytorna och dess osäkerheter kan beräknas från den sprickyta som uppstår då sprickan korsar borrkärnan, givet tillräcklig upplösning på ytan samt att ytan är representativ för hela sprickan. Denna beräknade råhet påverkar korrelationsstrukturen av hålrummet mellan de två ytorna som definierar sprickan. Således kommer median och varians för tjockleken samt dess korrelationsstruktur påverkas av vilken parameterkombination som dras från utfallsrummen för normalspänning och råhet. Detta medför att flödes- och transportegenskaperna är beroende av osäkerheterna i det geometriska ramverket, dvs osäkerheterna påverkar flödesvägar, flödestider, transportmotstånd och flödesvätt yta. Typiskt kommer en högre normalspänning som verkar på sprickan att resultera i längre flödestider, längre flödesvägar, högre flödesmotstånd och större flödesvätt yta medan en råare sprickyta typiskt kommer att resultera i kortare flödestider, längre flödesvägar, lägre flödesmotstånd och mindre flödesvätt yta. Slutsatsen av arbetet är således att osäkerheterna i att bestämma det geometriska ramverket påverkar resultatet för sprickornas tolkade flödes- och transportegenskaper.

  • Andersson, Gabriella
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekonomi och organisation (Inst.).
    Jonsson, Eva
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekonomi och organisation (Inst.).
    Transport Cartons' Impact on Supply Chain Efficiency2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Large product assortments commonly lead to that fast fashion retailers have a large number of transport cartons, with varying sizes, to distribute products from manufacturing sites to distribution centers. Ultimately, the transport cartons have a large impact on the supply chain efficiency, as they affect several nodes in the supply chain network. Previous research has considered transport cartons’ impact on individual supply chain nodes, but little research has been devoted to evaluate the transport cartons impact on the supply chain network as a whole. Thus, this thesis aims to contribute with knowledge to bridge the gap in literature by investigating how a company’s transport cartons affect the overall supply chain efficiency, by applying a holistic perspective.

    The thesis was conducted as a case study in collaboration with Hennes & Mauritz (H&M), aworld-leading fast fashion retailer. The research identifies opportunities and challenges related totransport carton usage, and how the cartons impact supply chain efficiency. Moreover, the research evaluates the costs associated with different sets of transport carton sizes, based on acost estimation model constructed on data provided by H&M. It is concluded that a small set oftransport carton sizes could increase supply chain efficiency and generate potential cost savingsdue to mainly two reasons. First, a small set of transport cartons could lead to efficient containerloading. Second, it could lead to efficient carton handling and optimal space utilization in thedistribution centers.

  • Frögren, Carolin
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Arkitektur.
    Captivating Architecture2019Independent thesis Basic level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The project concerns the subject of prisons. How should architects handle buildings that no one wants to enter and should comfort still be the aim of the building? These questions lead me to define my project with two main research questions: ”What is the purpose of a prison?” and ”How can the architecture aid the purpose of a prison?” Prisons are generally known to have four major purposes: Retribution, Prevention, Deterrance and Rehabilitation. Generally, rehabilitation have been prioritized the least. My focus was how the architecture can aid the purpose of rehabilitation, while still considering the balance of control, security, freedom and liberties. Swedish prisons today have one of three different levels of security. If a prisoner needs to change to a different security-level, it means moving them to a different prison, which is a security risk, among other things. My prison instead consists of four different levels of security within the same prison, and they are all organized around a “central park of opportunities”. This strategy is based on the current prison system in Sweden and the notion of free will. These four levels are connected to the park in different ways to emphasize the gradual release back to society. The park offers different places of work, education and variations in the landscape. It gives the inmates the opportunity to change their own circumstances for the better.

  • Madosh, Farzana
    et al.
    KTH, Skolan för industriell teknik och management (ITM).
    Ålander, Betty
    KTH, Skolan för industriell teknik och management (ITM).
    An Evaluation of the Marketing Process in B2B and B2C Startups2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Marketing is a key function for all organizations and is seen as essential in order to achieve success when launching a new business. Following from the overwhelming amount of accessible data for companies, there exist an urge to understand what activities to include in the marketing process and how to manage them. Despite the vital role and the urge to further understand marketing, there is a lack of research about marketing in the small entrepreneurial business context that is encountered in startups. In addition, a call for further development of empirical research is identified in the business to business (B2B) and business to consumer (B2C) dichotomy. Therefore, the purpose of this study was to evaluate the marketing process used by B2B and B2C Software as a Service (SaaS) startups. This in order to contribute with understanding of the marketing process in the startup context and contribute with development of the research within the B2B and B2C dichotomy. This was done by conducting a multiple case study where the empire was collected from four SaaS startups either selling to consumers or businesses.

    The empirical findings of the study show that the customer type, being a consumer or a business, affects the marketing process. Both differences and similarities were identified between the marketing process applied in the B2B and the B2C startups. Due to different levels of knowledge within the companies and different complexity levels in the buying process differences were found in the evaluation, segmentation, targeting and positioning done by the B2B and the B2C startups. It was found that the B2B companies put in less effort into the market analysis and segmentation compared to the B2C companies. Historically the channels utilized were identified to be different between the segments. However, a trend towards similar targeting channels was identified since the B2B segment is moving towards using more inbound marketing, which already is the main approach applied by the B2C segment. The B2B segment was, compared with the B2C segment, also identified to put more emphasize on achieving a position within the market that radiates credibility. Furthermore, the marketing process was found to be approached differently in startups than what was suggested in literature due to the lacking attention given to the scare resources and the innovative environment of a startup. A suggestion was therefore provided of how the marketing process better could be adapted to the startup context by including a feedback loop, making the marketing process more iterative.

  • Leon Perlasca, José Arturo
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Automated climate calculations and 3D value-based visualizations: An Integration of BIM and LCA2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The Swedish Government has set a goal to reach net zero emissions of greenhouse gases by 2045, which together with the commissioning to the Swedish Housing Agency to prepare requirements for a climate declaration that shall reduce the climate impact from buildings, has enforce the AEC industry to provide solutions that help reach these targets. The introduction of the integration of BIM technologies, together with the LCA methodology has been suggested as a key solution to solve this problem. To achieve the results for this study, two main objectives were stablished. The first objective was to develop a BIM model in SMC able to produce automated climate calculations. The second objective was to perform interviews with relevant actors about this tool. The integration of those objectives helped to answer the research questions of this study. This study provides a way of performing automated climate calculations for construction projects using classification of materials in SMC and calculations in Excel. It also has the ability to perform data visualization of the carbon footprints of the complements in the 3D models of the project using the GWP of the chosen materials. It can be said that it is a great tool to introduce to decision-makers an easy way to identify the hotspots of carbon emissions and choose more sustainable alternatives.

  • Engzell Waldén, Frithiof
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Arkitektur.
    Chasing Swans2019Independent thesis Basic level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The last few years have seen an increasingly infected public debate about the appearance of contemporary buildings. Regardless of where one personally stands, this ought to be cause for architects to examine their own understanding of aesthetics. This project is an exercise in articulating and examining questions of architectural form. The project is divided into three parts; Theory, Observation, and Design. The first aims to establish a broad overview of the theoretical discourse surrounding the subject of aesthetics in architecture, as well as formulate a position within it. The second part is an observation of aesthetic experiences in practice, in which three existing works of architecture are broken down into component formal properties, and the experiences these evoke are put into words. The final part is an exercise in articulating the reasoning behind aesthetic design decisions. A small self-imposed design task serves as the catalyst for a sequence of explicitly formulated and documented design choices, leading from inception to finished design. 

  • Disputas: 2019-11-05 12:00
    Jovanovic, Nenad
    KTH, Skolan för elektroteknik och datavetenskap (EECS). Research Technology Institute, Comillas Pontifical University, Spain; Delft University of Technology, the Netherlands..
    Electricity markets operation planning with risk-averse agents: stochastic decomposition and equilibium2019Doktoravhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    The growing penetration of renewable energy sources in electricity systems requires adapting operation models to face the inherent variability and uncertainty of wind or solar generation. In addition, the volatility of fuel prices (such as natural gas) or the uncertainty of the hydraulic natural inflows requires to take into account all these sources of uncertainty within the operation planning of the generation system. Thus, stochastic optimization techniques have been widely used in this context. From the point of view of the system operation, the introduction of wind and solar generation in the mix has forced conventional generators to be subject to more demanding schedules from the technical point of view, increasing for example the number of start-up and shutdown decisions during the week, or having to face more pronounced ramps. From the point of view of the market, all these technical issues are transferred to the market prices that are subject to greater volatility. This thesis focuses on the problem of risk management using the Conditional Value at Risk (CVaR) as a coherent risk measure. The thesis presents a novel iterative method that can be used by a market agent to optimize its operating decisions in the short term when the uncertainty is characterized by a set of random variable scenarios. The thesis analyses how it is possible to decompose the problem of risk management by means of Lagrangian Relaxation techniques and Benders decomposition, and shows that the proposed iterative algorithm (Iterative-CVaR) converges to the same solution as under the direct optimization setting. The algorithm is applied to two typical problems faced by agents: 1) optimization of the operation of a combined cycle power plant (CCGT) that has to cope with the volatility in the spot market price to build the supply curve for the futures market, and 2) strategic unit-commitment model. In a second part of the thesis the problem of market equilibrium is studied to model the interaction between several generating companies with mixed generation portfolios (thermal, hydraulic and renewable). The thesis analyses how the Nash equilibrium solution is modified at different risk-aversion level of the risk of the agents. In particular, the thesis studies how the management of hydroelectric reservoirs ismodified along the annual horizon when agents are risk-averse, and it is compared with the risk-neutral solution that coincides with a centralized planning when the objective is the minimization expected operational cost.

  • Kärrbrant, Robert
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Labriz, Daniel
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Analys av simulation för implementationer i en automatiserad verkstad2019Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    En verkstad som tillverkar växellådor planerade att bygga om verkstaden. Det fanns flera problem i verkstaden som indirekt påverkade produktionen. Att tåg stod stilla utan att göra ett aktivt arbete på en huvudled i verkstaden sågs som ett stort problem. Ett annat problem var att det fanns för många tåg i verkstaden. Den planerade ombyggnationen var till för att få ned antalet tåg i verkstaden. Med ombyggnationen ville verkstadens ansvariga undersöka ytterligare möjligheter hur verkstaden skulle kunna förändras och kunna lösa delar av problemen. Det var även intressant att se om möjliga implementeringar av verkstaden skulle ge en ökad produktion.

    Målen var att skapa ett simuleringsverktyg för att undersöka hur olika lösningar som baserades på ombyggnationen skulle kunna påverka ett tåg som fyllde på material till monteringslinor i verkstaden. För att kunna testa olika lösningar behövde en simuleringsmodell utvecklas och verifieras mot den befintliga lösningen i verkstaden. Därefter utökades modellen för att testa nya lösningar.

    Från verkstaden fanns det data på konsumering av material. För tåget som skulle fylla på material fanns det teoretiska tider för olika arbetsmoment. Konsumeringen av material uppförde sig enligt en slumpfördelning som var normalfördelad. Resultatet blev att endast konsumeringen av material kunde verifieras då det bara fanns data på hur konsumtionen av material skedde. Resterande delar av simuleringen använde teoretiska planerade värden. Av de undersökta lösningarna var det en lösning med en ny hållplats på en mindre trafikerad väg, där ett tåg kunde vänta, som visade ett mer önskat resultat än de andra som undersöktes.

  • Dydek, Marta
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Arkitektur.
    A redesign of a pedestrian passage in Skärholmen Centrum: - variation on modernism´s theory of functional color2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Original project of Skärholmen was composed of a system of public spaces, but this was `broken´  by the closure of the connection between the two squares in 1986. Street between shopping buildings became part of the shoping mall. The current situation is dominated by the activity of consumption, and Storholmsgatan is characterized by an atmosphere of anxiety and constant over-stimutation. The project aims to think through what form of ´restoration´ of this system of public spaces could take. How can we work with quite constrained, long, linear spaces as site for architecture? What is the role of rhythm in producing experience? A theme for design is to produce spacial hierarchy and make  a contemporary variation on modernism’s approach of the funcional color in design process.