12345 151 - 200 of 211
rss atomLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
  • Sun, Jiuwu
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Message Classification Based Continuous Data Transmission for an E-health Embedded System2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis aims to develop an e-health embedded system with a real-time operating system (RTOS), which allows users to monitor their body condition, including heart rate and breath, through Bluetooth Low Energy (BLE). Meanwhile, the device is also able to provide guidance for breathing by simulating breathing according to given parameters. In practice, the system samples the heart rate every two milliseconds. To ensure reliability and validity, results are expected to be sent in realtime. However, numerous data cannot be transmitted directly without being processed. Otherwise, the system will crash, and hard faults will occur.

    A general idea to solve this problem is to classify messages into two categories based on the priority. One is urgent, and the other is unimportant. Two solutions are proposed, one using a unidirectional linked list, and the second using queues.

    Based on an ARM micro-controller, the e-health embedded system is designed and implemented successfully. The evaluation results show that the solution using a linked list is suitable for the system, while the solution using queues is unable to solve the problem. With the help of the message classification, the urgent messages can be timely transmitted with continuous data.

  • Badadamath, Bharathesh
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Design, evaluation and use of a microfluidic device for automated production of mucin microparticles for cell encapsulation for diabetes therapy2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Droplet microfluidics has prevalent growth in a wide range of applications in the life science field. This project is one such example where we used a droplet microfluidics tool for treating diabetes mellitus type 1. Mucin hydrogels (Muc-gels) modulate the immune response driving biomaterialinduced fibrosis.[1]. In this project, we have fabricated a droplet microfluidic device for encapsulation of Min6m9 cells(Insulin secreting cells) in mucin hydrogel microparticles. Initially a novel microfluidic circuit design made for production of droplets and fabricated the same by micromachining and 3D printing. Before producing cell encapsulated mucin hydrogel droplets, we have evaluated the functionality of the device by using water as a model we have tested mixing of components from two inlet fluid channels, the size distribution of water droplets produced at different pressure values, droplet generation rate. Thereafter, Min6m9 cells are encapsulated in mucin microparticles, viability studies have been made and observed growth of cells which eventually forming islet-like structure after 15 days of incubation. Performed experiments to make microfluidic device to work in an automated format by using a fluid handling robot for mass production and solving other problems that occurred while encapsulation.

  • Xu, Tian
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Enabling Database-based Unified Diagnostic Service over Local Interconnect Network2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Unified Diagnostic Service (UDS), which is an international and not a company-specific standard, is used in almost all new electronic control units (ECUs) by now. Modern vehicles have a diagnostic interface for off-board diagnostics, which makes it possible to connect a diagnostic tool to the vehicle’s bus system like Controller Area Network (CAN) and Local Interconnect Network (LIN). However, as the most commonly used method, sequential method on the UDS data transmission over LIN does not only result in low reliability and flexibility but also fails to meet the standard for LIN development defined in the latest LIN specification published by the consortium. With standard workflow and application interfaces, this Master Thesis will develop and evaluate a database-based method to build a UDS system over LIN, where all the information for the network is defined in the LIN database, and the protocol properties are realized in a reusable model so that it can be easily reconfigured for the future development of other services. As a result, a new method including a layered-structure LIN protocol model and a LIN database has been successfully designed and implemented. The prototype is built on the device PIC32MX795, and the database can be deployed by the configuration tool to specify the UDS communication schedule. Further, several performance evaluations have been performed. The tests indicate that the system is qualified on the limited hardware platform and the configuration flexibility is proved by different databases.

  • Jiang, Jiani
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Experimental Study on Machine Learning with Approximation to Data Streams2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Realtime transferring of data streams enables many data analytics and machine learning applications in the areas of e.g. massive IoT and industrial automation. Big data volume of those streams is a significant burden or overhead not only to the transportation network, but also to the corresponding application servers. Therefore, researchers and scientists focus on reducing the amount of data needed to be transferred via data compressions and approximations. Data compression techniques like lossy compression can significantly reduce data volume with the price of data information loss. Meanwhile, how to do data compression is highly dependent on the corresponding applications. However, when apply the decompressed data in some data analysis application like machine learning, the results may be affected due to the information loss. In this paper, the author did a study on the impact of data compression to the machine learning applications. In particular, from the experimental perspective, it shows the tradeoff among the approximation error bound, compression ratio and the prediction accuracy of multiple machine learning methods. The author believes that, with proper choice, data compression can dramatically reduce the amount of data transferred with limited impact on the machine learning applications.

  • Prato, Gabriele
    KTH, School of Electrical Engineering and Computer Science (EECS).
    New Methodologies for Fashion Recommender Systems2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Traditional Recommender Systems rely on finding similarities between users and/or between items. In its broadest definition, a Recommender System tries to predict the preference a user would give to an item. While Content-Based approaches try to discover similarities between items and then predict a user’s preference based on its past interactions with the items, Collaboritve-Filtering approaches try to find similarities between users in order to recommend to an user what similar users already bought.

    In the fashion domain, though, users may not buy an item per se, but rather because it would fit in an ideal outfit that they may want to wear. This behaviour implies that the items content similarity between the items already bought by the user is not enough to make accurate predictions. Thus, it would be more reasonable to suggest the purchase of compatible clothes, rather than similar ones.

    The problem of scoring the compatibility of different outfits and learning a concept of style has already been tackled in the research community by the application of different machine learning techniques. However, the tasks and the datasets used to evaluate state-of-the-art models make some unrealistic assumptions that would not hold in a real-case scenario. This thesis introduces a novel algorithm to tackle the problem of learning outfit styles, in order to classify ensemble of clothes as fashionable outfits and complete them in a fashionable manner. Moreover, this work presents a proper comparison with the state-of-the-art models on the most used public academic datasets in this domain and on a real industrial dataset, provided by H&M as industrial partner of this research. In addition to this, a novel evaluation task, that releases some of the constraints existing in the tasks presented in literature, is introduced in order to asses the potentials of the different algorithms when dealing with problems more similar to those faced in real-case scenarios. Finally, this thesis attempts to move the problem of outfit completion from a general classification problem, into the recommender Systems domain and evaluates the performances of these algorithms using some of the typical metrics used in Information Retrieval problems.

  • Sun, Silu
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Design and Implementation of Partial Firmware Upgrade2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Device Firmware Upgrade (DFU) is now widely used on PC and smartphones for users to enjoy the latest applications. The project is derived from the new device of Yohoo and the firmware embedded in the system. This system can guide users on how to breathe through multiple sensory effects to reduce the harm from excessive stress. In order to be applied by different people, some breathing courses and personal settings will be used in the system, which makes the upgrade of the internal firmware of the device more important. However, the firmware upgrade for some embedded devices is not as rapid and convenient as PC and smartphones, which is still erasing and then programming the whole storage. This is a waste of time and meaningless wear to the entire device. In order to solve this problem and improve the efficiency of the firmware upgrade, the partial firmware upgrade is proposed in this project, and the storage method of new codes is improved to get better performance during the partial DFU process. The idea of wear leveling is introduced to extend the lifetime of the internal storage.

    As a result, the partial firmware upgrade feature was successfully designed and implemented, and integrated and tested on new devices. At the end of this work, the prototype system of the embedded software based on the nRF52832 microcontroller has basically been designed, improved and tested, and some functions which need to be updated instead of the whole firmware can be transmitted via Bluetooth and work normally. For the specific case of partial DFU, the firmware package size that maximizes the update efficiency is obtained through testing. In addition, the flash module in the chip has been divided into multiple portions for the update. The wear-leveling method ensures that when a certain function is updated multiple times, one certain part of the flash will not be overused, but the entire block will be used uniformly to alleviate the adverse effects of data abnormality or loss caused by damaged bits of the flash memory. In addition, the lifetime of the flash memory is prolonged and the industrial waste is reduced at the same time.

  • Shokrollahi Yancheshmeh, Ali
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Multi-Tenancy Security in Cloud Computing: Edge Computing and Distributed Cloud2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    With the advent of technology cloud computing has become the next generation of network computing where cloud computing can deliver both software and hardware as on-demand services over the Internet. Cloud computing has enabled small organizations to build web and mobile apps for millions of users by utilizing the concept of “pay-as-you-go” for applications, computing, network and storage resources as on-demand services. These services can be provided to the tenants in different categories: Infrastructure as a Service (IaaS), Platform as a Service (PaaS) and Software as a Service (SaaS). In order to decrease the costs for the cloud users and increase resource utilization, cloud providers try to share the resources between different organizations (tenants) through a shared environment which is called Multi-Tenancy.

    Even though multi-tenancy‟s benefits are tremendous for both cloud providers and users, security and privacy concerns are the primary obstacles to Multi-Tenancy.Since Multi-Tenancy dramatically depends on resource sharing, many experts have suggested different approaches to secure Multi-Tenancy. One of the solutions is resource allocation and isolation techniques. In most cases, resource allocation techniques consider but are not sufficient for security. OpenStack community uses a method to isolate the resources in a Multi-Tenant environment. Even though this method is based on a smart filtering technique to segregate the resources in Compute nodes (the component that the instances are running on it in OpenStack), this method is not flawless. The problem comes up in the Cinder nodes where the resources are not isolated. This failure can be considered as a security concern for a Multi-Tenant environment in OpenStack.

    In order to solve this problem, this project explores a method to secure MultiTenancy for both sides in the Compute node and for backend where Block Storage devices for the instances can be isolated as well.

  • Garcia Sacristan, Eduardo
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Exploring eye-tracking and augmented reality interaction for Industry 4.0: Study of eye-tracking and augmented reality for manipulation, training and teleassistance2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this project, we explore eye-tracking enabled interaction in augmented reality for training, teleassistance and controlling Internet of Things devices in the forthcoming manufacturing industry. We performed a design exploration with industrial partners that ended up with the design and implementation of a series of prototypes using gaze for interaction. To explore the possible benefits, we compared their efficiency, effectiveness and user experience against counterparts not using gaze. Overall, we found that participants using the eye-tracking implementation scored better on a subjective user experience questionnaire regarding comfort, stress and perceived completion time. In training prototypes, participants performed faster and committed fewer errors, while in the teleassistance and the Internet of Things prototypes they performed similarly to mouse or touch. We hence argue that augmented reality and eye-tracking can improve the overall experience of users in the manufacturing industry or at least perform equally as well stablished user input devices with the benefit of freeing the user’s hands.

  • Soares da Costa, Tomás
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Characterization of Passive Intermodulation Distortion in MultiBand FDD Radio Systems2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Intermodulation distortion (IMD) is a phenomenon that results in generation of spurious distortion signals when two or more signals of different frequencies pass through a nonlinear system. In general, IMD occurs in active circuits of a radio system, however, passive wireless components such as filters, transmission lines, connectors, antennas, attenuators etc., can also generate IMD particularly when transmit power is very high. The IMD in the latter case is referred to as passive intermodulation (PIM) distortion. With the continuing advancement of radio system coupled with the radio spectrum scarcity, PIM interference is recognized as a potential obstacle to achieving the full capacity of a radio network.

    The assiduous enhancement of radio systems for faster data speeds and higher capacity further exacerbate the PIM interference problem. Features like carrier aggregation (CA) and multiple input multiple output (MIMO) make the PIM a more problematic issue. In modern co-sites, radio systems are often coupled together, operating in multiple bands. Furthermore, in frequency division duplex (FDD) systems, transmitter (Tx) and receiver (Rx) operate simultaneously. In such scenarios, PIM is likely to occur in the signal’s path and may potentially hit multiple Rx bands causing undesired interference.

    The PIM sources in the BS radio systems can be divided into two groups, namely internal and external. Internal sources are the passive components within the radio such as filters, transmission lines, connectors, antennas, etc. External sources, on the other hand, are the passive elements beyond the BS antenna but within the RF signal path such as metallic and rusty objects in antenna near field. For both types of sources, the high power current flowing through such passive objects can prompt a nonlinear behavior that in turn generates IMD.

    This thesis addresses PIM distortion in multiband BS radio systems by devising a characterization. For this purpose, the research begins by establishing a mathematical model for IMD and reviewing the physics that prompt nonlinear behavior in these sources. Afterwards, the enhancements in radio systems that enlarge the bandwidths and exacerbate PIM are discussed. In particular, how IMD is worsen in broadband radios is highlighted, and to complement this discussion, a review of PIM mitigation techniques is also presented. In the final part of this work, extensive lab measurement results are presented where effects of PIM with external PIM sources are analyzed and discussed. Overall, this thesis helps to build a better understanding of PIM interference problem in radio systems by providing useful insights into the nonlinear mechanisms in passive components causing PIM.

  • Ahmed, Sammy
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Navigational system for visually impaired people in a swimming pool.2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this thesis conducted at IBM in Amsterdam we explore the ability Computer Vision has to assist visually impaired people in navigating a swimming pool. We examine different Computer Vision techniques and develop an algorithm to navigate a swimmer in a pool. In cooperation with a center for visually impaired people we collect a video-dataset that reflects the use-case at hand for testing, and to be able to utilize data-driven algorithms. The Computer Vision algorithm designed was implemented using Deep Learning (CNN) and statistical methods like Kalman filtering. Evaluation of the algorithm was done using both the dataset and by comparing the algorithm to the state of the art in pedestrian tracking using the MOT benchmark. The MOT benchmark was used in lack of standardized tests for tracking in pools, it provided an outlook of the algorithm’s performance in comparison to other methods. The results showed that the tracker could compete with the state of the art in pedestrian tracking as well as navigate swimmers in a pool. While the dataset needs to be expanded to perfect the algorithm, the thesis concludes that data-driven Computer Vision techniques can in a robust way navigate a swimmer in a pool with the help of statistical filtering. This is an important step to make visually impaired people more autonomous and in consequence healthier.

  • Daiman Khan, Muhammad
    KTH, School of Electrical Engineering and Computer Science (EECS).
    An investigation into trust between an SAV and its passengers2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    As more and more shared autonomous vehicles (SAVs) are introduced in mixed traffic conditions, it calls upon research exploring the relationship between an SAV and its passengers. It is assumed that in the future SAVs will be completely autonomous, with no operator on-board, resulting in the loss of implicit communication between a driver and a passenger with effects on trust. This served as motivation to perform a study investigating the definition of trust from the passenger’s perspective.

    Initially a state-of-the-art study was conducted to research previous work and identify existing trust frameworks. Three field studies took place on an operational SAV which included interviews and observations with on-board operator and passengers. The aim of which was to understand the trust dynamics between the operator and passenger but more importantly, between the SAV and its passengers. The results revealed dependency on the operator during the commute in deadlock situations. To investigate trust attributes, interviews and observations were conducted with passengers of a regular bus as well as experts from the field of transportation. Situational awareness of the SAV and communication of SAV intention were deemed most important towards building trust with caution towards information overload. Furthermore, three participatory design studies conducted showed a multi-modal approach as the preferred way of communication, with visual and auditory modalities being the most favorable choice.

    The overall results showed that a communication and feedback channel with an SAV and its passengers is necessary in creating trust in the absence of a driver.

    Future studies could use the findings from this thesis as the building blocks for creating a communication interface to enhance passengers trust in an SAV.

  • Sivard, Gunilla
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    AN INTEGRATED ARCHITECTURE FOR FUNCTIONAL PRODUCTS2003In: INTERNATIONAL CONFERENCE ON ENGINEERING DESIGNICED 03 STOCKHOLM, AUGUST 19-21, 2003, 2003Conference paper (Refereed)
    Abstract [en]

    There is an increasing trend in industry of selling services in addition to physical products. Infunctional sales, companies sell the service of delivering the function of the product asopposed to selling the product itself. While there is a long tradition of structured developmentand management of purely physical goods, there is a lack of such methods for services, andfor the mixture of service and goods - so called functional products.This paper describes an effort of defining a formal model of services, contributing to theefforts of structuring, visualizing and managing functional products in analogue with purelyphysical products.A modular architecture for services is presented, based on the paradigm of defining servicesas discrete, decomposable activities. Sub activities, so called service modules, are described interms of the activity’s properties and interfaces to other service modules. Since the method isbased on principles for uncoupled design, it provides support for creating transparent andflexible architectures with a minimum of built in dependencies between functions and theirphysical implementation.The service module aggregation and representation principles are described in relation to anindustrial distribution case.

  • Wennerberg, Ulme
    KTH, School of Electrical Engineering and Computer Science (EECS).
    An evaluation of BERT for a Span-based Approach for Jointly Predicting Entities, Coreference Clusters and Relations Between Entities2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This degree project examines and evaluates the performance of various ways of improving contextualization of text span representations within a general multi-task learning framework for named entity recognition, coreference resolution and relation extraction. A span-based approach is used in which all possible text spans are enumerated, iteratively refined and finally scored. This work examines which ways of contextualizing the span representations are beneficial when using the text embedder BERT. Furthermore, I evaluate to what degree graph propagations can be used together with BERT to enhance performance further, and observe F1-score improvements over previous work. The architecture sets new state-of-the-art results on four datasets from different domains - SciERC, ACE2005, GENIA and WLPC. Qualitative examples are provided to highlight model behaviour and reasons for the improvements are discussed.

  • Wobrock, David
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Image Processing using Graph Laplacian Operator2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The latest image processing methods are based on global data-dependent filters. These methods involve huge affinity matrices which cannot fit in memory and need to be approximated using spectral decomposition. The inferred eigenvalue problem concerns the smallest eigenvalues of the Laplacian operator which can be solved using the inverse iteration method which, in turn, involves solving linear systems. In this master thesis, we detail the functioning of the spectral algorithm for image editing and explore the behaviour of solving large and dense systems of linear equations in parallel, in the context of image processing. We use Krylov type solvers, such as GMRES, and recondition them using domain decomposition methods to solve the systems on high-performance clusters. The experiments show that Schwarz methods as preconditioner scale well as we increase the number of processors on large images. However, we observe that the limiting factor is the Gram-Schmidt orthogonalisation procedure. We also compare the performances to the state-of-the-art Krylov-Schur algorithm provided by the SLEPc library.

  • Tziatzios, Dimitrios
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Model-based Testing for SQL Databases2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Database testing is an expensive and time consuming process, often performed with manually written test code. Automating database testing involves test case generation and test oracles which examine and verify the results. Previous work for database testing has shown a wide variety of techniques and testing tools, including specification languages and symbolic execution. In this thesis, we present a novel approach for SQL database testing. We use Modbat, an open-source tool for model-based testing which was recently used to test complex systems such as Apache Zookeeper. Our approach includes the test model, which generates test cases and builds queries in order to test the database, and the test oracle which investigates the results from the database and compares them with the expected results. We evaluate the effectiveness of our approach by using a number of metrics: execution time, test code and model size, human effort, test coverage and defect detection efficiency.

  • Bentersten, William
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems.
    Upptäcka kritiska ändringar i JSON-meddelandeni webb-API:er2020Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Ett sätt att utveckla webbapplikationer är att göra det i två delar. Dels ett API, dels en klient. Denna rapport fokuserar på JSON-API:er och på att hitta en lösning för att identifiera kritiska ändringar i JSON-meddelanden innan de påverkar sin avseddak lient på ett oönskat sätt.En fallstudie är genomförd hos ett företag som utvecklar sina webbapplikationer i två delar. Resultatet är en utvecklad webbapplikation (ett verktyg) som löser problemet genom att spela in API-förfrågningar som repeteras mot flera olika versioner av API:et. Versionstaggade svar samlas in och jämförs mot varandra med olika avseenden. Webbapplikationen (verktyget) lyckas på ett tillfredställande sätt identifiera kritiska ändringar i JSON-meddelanden. Detta verifieras med hjälp av ett test-API, och bekräftar därmed examensarbetets hypotes.För att kunna testa ett API, vars bakomliggande applikation är stateful, förväntas den applikationen vara återställd till ett standardiserat tillstånd inför varje användning av verktyget. Detta är en begränsning. Det finns en utvecklingspotential i att få verktyget att fungera även mot autentiserade API:er.

  • Haldén, Fred Jonathan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems.
    Yao Håkansson, Joel
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems.
    A Comparison between Chatbots for Handling Administrative Healthcare Tasks2020Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Chatbots are used in many fields to reduce the amount of repetitive work. While chatbots are proved to be great help in retailer business, tourism related services, it is little known about usability of chatbots in more sensitive field such as healthcare. A study was conducted to examine the possibilities whether a chatbot could be used to automate administrative tasks within the Swedish healthcare. Three chatbots were developed, each one using different framework. Each chatbot was tested with participants acting as a patient, freely using each chatbot, and filling out a quantitative evaluation after the test. Results from participants'responses to the quantitative evaluation and SWOT analysis showed that chatbots are helpful, user-friendly and have the opportunity to integrate with various databases and many services. Participants preferred the chatbot that could handle voice interaction. The results also showed that the chatbots were helpful in registering cases and answering frequently asked questions. Additionally, it was observed that chatbots are efficient when their work is complemented by a healthcare specialist. This allows concluding that a chatbot is a promising potential tool to automate administrative tasks within the Swedish healthcare.

  • Redaelli, Tiago
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems.
    Ekedahl, Jacob
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems.
    Automated Intro Detection ForTV Series2020Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Media consumption has shown a tremendous increase in recent years, and with this increase, new audience expectations are put on the features offered by media-streaming services. One of these expectations is the ability to skip redundant content, which most probably is not of interest to the user. In this work, intro sequences which have sufficient length and a high degree of image similarity across all episodes of a show is targeted for detection.

    A statistical prediction model for classifying video intros based on these features was proposed. The model tries to identify frame similarities across videos from the same show and then filter out incorrect matches. The performance evaluation of the prediction model shows that the proposed solution for unguided predictions had an accuracy of 90.1%, and precision and recall rate of 93.8% and 95.8% respectively.The mean margin of error for a predicted start and end was 1.4 and 2.0 seconds. The performance was even better if the model had prior knowledge of one or more intro sequences from the same TV series confirmed by a human. However, due to dataset limitations the result is inconclusive.

    The prediction model was integrated into an automated system for processing internet videos available on SVT Play, and included administrative capabilities for correcting invalid predictions.

  • Wang, Yujue
    KTH, School of Electrical Engineering and Computer Science (EECS), Computer Science, Communication Systems, CoS.
    Enhancing interoperability for IoT based smart manufacturing: An analytical study of interoperability issues and case study2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In the era of Industry 4.0, the Internet-of-Things (IoT) plays the driving role comparable to steam power in the first industrial revolution. IoT provides the potential to combine machine-to-machine (M2M) interaction and real time data collection within the field of manufacturing. Therefore, the adoption of IoT in industry enhances dynamic optimization, control and data-driven decision making. However, the domain suffers due to interoperability issues, with massive numbers of IoT devices connecting to the internet despite the absence of communication standards upon. Heterogeneity is pervasive in IoT ranging from the low levels (device connectivity, network connectivity, communication protocols) to high levels (services, applications, and platforms). The project investigates the current state of industrial IoT (IIoT) ecosystem, to draw a comprehensive understanding on interoperability challenges and current solutions in supporting of IoT-based smart manufacturing.

    Based upon a literature review, IIoT interoperability issues were classified into four levels: technical, syntactical, semantic, and organizational level interoperability. Regarding each level of interoperability, the current solutions that addressing interoperability were grouped and analyzed. Nine reference architectures were compared in the context of supporting industrial interoperability. Based on the analysis, interoperability research trends and challenges were identified.

    FIWARE Generic Enablers (FIWARE GEs) were identified as a possible solution in supporting interoperability for manufacturing applications. FIWARE GEs were evaluated with a scenario-based Method for Evaluating Middleware Architectures (MEMS).  Nine key scenarios were identified in order to evaluate the interoperability attribute of FIWARE GEs. A smart manufacturing use case was prototyped and a test bed adopting FIWARE Orion Context Broker as its main component was designed. The evaluation shows that FIWARE GEs meet eight out of nine key scenarios’ requirements. These results show that FIWARE GEs have the ability to enhance industrial IoT interoperability for a smart manufacturing use case.

    The overall performance of FIWARE GEs was also evaluated from the perspectives of CPU usage, network traffic, and request execution time. Different request loads were simulated and tested in our testbed. The results show an acceptable performance in terms with a maximum CPU usage (on a Macbook Pro (2018) with a 2.3 GHz Intel Core i5 processor) of less than 25% with a load of 1000 devices, and an average execution time of less than 5 seconds for 500 devices to publish their measurements under the prototyped implementation.

  • Nummisalo, Linda Maria
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems.
    Needs and requirements for the development and application of safe and cost-efficientmedical technology in low resource settings2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Growing populations and especially the growing proportion of elderly in the developing countries in South Asia pose an increasingly higher pressure on the health care systems in these countries. For example, in Bangladesh, a part of the pressure is currently eased by the unofficial health care workers called village doctors but with the cost of wrong diagnoses and unnecessary medications leading to excess use of e.g. antibiotics. In order to help to produce a correct diagnosis and in planning the follow-up or preventive measures to improve the general health of the population, medical technology could be brought to the village doctors. Even though medical equipments are already been imported from developed countries to developing countries it has not notably improved the situation. This project has been conducted to unravel factors that affect bringing new medical technology to low resource settings, and to find outthe specific needs that countries with large rural populations but low income status have with medical technology.

    The purpose of this study is to investigate what demands should be placed on basic monitoring medical devices to ensure highly accurate and reliable readings, similar to those in Europe, but also an affordable product that meets the specific needs of rural health care in low income countries such as Bangladesh. This study also aims to find out what is the current need in therural areas of Bangladesh. The goal on the long run is to contribute to the development of safe and efficient medical devices that would increase the accessibility and quality of healthcare especially for the people living in the rural areas.

    The research questions were approached by first defining the current situation and the currenly known barriers in bringing two cost efficient medical devices for monitoring purposes to the Bangladeshi-market, and to define which requirements they should fulfil for the needs of the public health care. Secondly, European legislation was examined to research how the goal could be reached in practice. The methodology chosen for this project is qualitative methodology based on literature research and standard open-ended interviews. In addition, sensor-development work was done at KTH to study the properties of the sensors and the electric circuits.

    The results of this project show that, currently, medical technology is not used in large parts in South Asia such as in the rural areas of Bangladesh, but that there is a need and potential market for new devices that has not been researched before. Medical companies are aware of this, but the technology has not been developed yet to meet the local conditions. The results of this report suggest the following areas to be researched when developing new medical technology for rural areas in Bangladesh: technical requirements from an internationally acknowledged regulation (e.g. the EU regulation 2017/745 and ISO standards), reusability, robustness, user friendliness, post market surveillance, monitoring of performance and maintenance work.

  • Morgunova, Maria
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.).
    The global energy system through a prism of change: The oil & gas industry and the case of the Arctic2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The energy industry as a whole and the oil & gas industry in particular is experiencing changes under the influence of a variety of trends and the changing needs of society. Current social, economic, environmental and climate challenges are raising sharp questions for the established principles of energy production and consumption, increasingly arguing for sustainable trajectories in the development of the global energy system. There are significant international efforts to improve energy sustainability, and powerful trends are being established. However, the change in the global energy system is happening at a slower pace.

    The oil & gas industry has been a substantial part of the global energy system for decades. While it has significantly contributed to global development and enabled industrialization, it has also affected the environment. Currently, the role of the oil & gas industry is shifting, while it continues to satisfy more than half of global energy demand. Simultaneously, the relationship between the oil & gas industry and the sustainable development of the global energy system is largely overlooked. This thesis questions the validity of such neglect, and raises the importance of exploring sustainable development of the global energy system with its relationship to the oil & gas industry.

    Through the perspectives of sustainability transitions and industrial dynamics domains, this thesis aims to explore the role of the ‘socio-technical regime’ in sustainability transitions of socio-technical systems. This thesis focuses on three particular aspects: (1) the factors of change in the regime; (2) the way the regime responds to these factors of change; and (3) the relationship between the sustainable development of the socio-technical system and the regime. This thesis is based on two interrelated studies, devoted to certain aspects of change within the oil & gas industry, and an in-depth investigation of the case of Arctic offshore oil and natural gas resources exploitation.

    The thesis provides an insight into the critical aspects of change within the global energy system through analysis of the oil & gas industry, and reveals an understanding of how sustainable change in the global energy system can be facilitated. From a theoretical perspective, this thesis contributes to sustainable energy transitions and industrial dynamics literature on sustainable change of large socio-technical systems with an emphasis on the regime. Theoretical implications underline the need to revise the existing links and connections between socio-technical system levels in order to facilitate change, show the need for typologies of factors of change, and suggest more attention to qualities and capacities of regimes. Finally, this thesis employs system thinking and a multidisciplinary approach in energy related and sustainability transitions research.

    From a practical perspective, this thesis provides analytical frameworks, tools and concepts to be useful for policy makers, strategy consultants, governmental organizations, and industry, as well as suggests some insights into the development and change in the global energy system.

  • Lei, Mingtian
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Graphic Interface and Robot Control System Design with Compensation Mechanism2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Nowadays, many researchers are developing several useful prototypes to control robots by AR/VR devices. However, the robots they used are all ROS supported and the prototypes do not have a feedback mechanism to achieve error compensation. For industrial robots, there have lots of type robots do not support ROS and serve production line from many years ago. It is a challenge that how to connect these legacy robots with new AR/VR technology to achieve both human-robot collaboration and cost-saving. This thesis describes a series of works developed in order to control a non-ROSsupported industrial robot, KUKA KR6 R700 Sixx, by Unity graphic interface. The main goal of this thesis work is to establish a backend system structure to support control commands from Unity that can be executed by the robot. Furthermore, a compensation mechanism with closed-loop function is developed, which can adjust if the feedback data of the final robot pose is out of the tolerance scope. In order to achieve this, some available code packages and Unity assets are applied i.e. rosbridge_suite, ROS# and KukaRosCommunication. Moreover, some useful functions are also developed to achieve i.e. pick and place. To understand the availability of the system, two tests have been completed: compensation mechanism test and system delay test. The compensation mechanism test result shows that more than 98% position error can be compensated. The system time delay test result shows that the system needs further development to achieve real-time control.

  • Kowalczewski, Jakub
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Normalized conformalprediction for time series data2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Every forecast is valid only if proper prediction intervals are stated. Currently models focus mainly on point forecast and neglect the area of prediction intervals. The estimation of the error of the model is made and is applied to every prediction in the same way, whereas we could identify that every case is different and different error measure should be applied to every instance. One of the state-of-the-art techniques which can address this behaviour is conformal prediction with its variant of normalized conformal prediction. In this thesis we apply this technique into time series problems. The special focus is put to examine the technique of estimating the difficulty of every instance using the error of neighbouring instances. This thesis describes the entire process of adjusting time series data into normalized conformal prediction framework and the comparison with other techniques will be made. The final results do not show that aforementioned method is superior over an existing techniques in various setups different method performed the best. However, it is similar in terms of performance. Therefore, it is an interesting add-on to data science forecasting toolkit.

  • Strandberg, Anna
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Vlk, Vendela
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Gamification som motivation till ett förändrat konsumtionsbeteende: En studie hur spelmekanismer och spelelement kan användas inom hållbar konsumtion2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Today, the climate has become an increasingly important question where consumption is one of the main contributing factors to global warming. The climate changes will continue to have a negative impact, not only on the environment but also on people, if nothing is done to reduce the greenhouse gases in the atmosphere. Although, the increased awareness regarding how consumption affects the environment, where individuals usually have a positive attitude towards sustainable consumption, their attitudes do not always correspond with their actions.

    Recent years development in the field of Information and communication technology (ICT) has resulted in an era of new innovative ideas and functionalities. One area within the ICT field that specifically aims to change certain behaviour amongst individuals is gamification. Compared to games, gamification has the ability to involve and motivate users to change a certain behaviour. Gamification includes different mechanisms and elements from games and if the implementation is made properly it can reach out and affect individuals on a higher level than before. The research question that this study aimed to investigate was which game mechanisms and elements in gamification that can influence people’s behaviour so that they maintain and consume more sustainably.

    The aim of the study was to evaluate various game mechanisms within gamification and the goal was to conclude which game mechanisms and elements that could be used to change the behaviour of the consumers to make them become more aware of their consumption habits. The study used a qualitative research method and interviews to evaluate the selected game mechanisms. The result consisted of the summarized interviews that was analysed and compared to previous research where gamification had been used and implemented. The answer to the study’s research question was determined to be that all implementations of gamification generally yield positive results on people’s consumption behaviour if they are implemented properly. Furthermore, long-term usage is essential as it contributes to develop a sustainable habit of consumption. The reached conclusion intended to contribute to an extended insight in how gamification can be implemented in the context to make consumers more aware of their behaviour regarding their consumption.

  • Fallah, Parmiss
    KTH, School of Electrical Engineering and Computer Science (EECS).
    FPGA Virtualization2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    During recent years, the population of internet users has sharply increased and more applications are utilizing data centers. Telecommunication companies are constantly trying to make communication applications faster to provide faster cellular networks. Moreover, recent computation applications have been analysing very big data and need higher performance. On the other hand, transistor scaling has almost come to its end, which makes it difficult to provide higher performance and efficiency in processors. As a solution, applicationspecific hardware platforms are used to accelerate the applications and improve the performance, energy consumption, and latency. Field programmable gate arrays (FPGAs) are the most popular means of hardware acceleration since they are reprogrammable and consume relatively low power. Connecting FPGAs to servers through high-speed PCIe links is the most common way of deploying them in data centers. However, FPGA resources will not be efficiently used if they are all assigned to one specific task or user. One task may just need a fraction of the FPGA resources. Therefore, a single FPGA can be shared among different applications in terms of area and time. FPGA virtualization is done by partitioning the fabric into isolated regions programmed dynamically based on active applications.

    This thesis proposes a hardware architecture that enables an FPGA board to be deployed on a server. In this design, two isolated reconfigurable regions have been provided on the FPGA to accommodate accelerators. Our design is configured to accelerate Low-Density Parity Check (LDPC) encoding and decoding applications for 5G. However, the accelerators can be replaced by any other user-defined designs by simply reconfiguring a region on the FPGA. Compared to the Xilinx SDAccel reference platform for the same board, this design provides isolated regions with 25% more logic resources to be used by the users. Also, the data transfer latency has been significantly decreased to make the platform more compatible with the communication systems applications.

  • Milošević, Jezdimir
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control).
    Security metrics and allocation of security resources for control systems2020Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Achieving a sufficient level of security of control systems is very important, yet challenging. Firstly, control systems operate critical infrastructures vital for our society. Hence, attacks against them can result in dire consequences. Secondly, large numbers of security vulnerabilities typically exist in these systems, which makes them attractive targets of attacks. In fact, several attacks have already occurred. Thirdly, due to their specific nature, securing control systems can be costly. For example, their real time availability requirements complicate the deployment of security measures, and control system equipment with limited computational power is unsuited for many security solutions. Motivated by the necessity of control systems security, we study two security-related applications. The first application considers classifying and preventing security vulnerabilities. We aim to first characterize the most critical vulnerability combinations in a control system, and then prevent these combinations in a cost-effective manner. To characterize the critical vulnerability combinations, we develop an impact estimation framework. Particularly, we use a physical model of the control system to simulate the impact that attack strategies may have on the physical process. Our framework is compatible with a number of attack strategies proposed throughout the literature, and can be used to estimate the impact efficiently. To prevent critical vulnerability combinations in a cost-effective manner, we develop a security measure allocation framework. The framework includes an algorithm for systematically finding critical vulnerability combinations, and two approaches for allocating security measures that prevent these combinations cost-effectively. The second application considers actuator security. Actuators are vital components of control systems to protect, since they directly interact with the physical process. To evaluate the vulnerability of every actuator in a control system, we develop actuator security indices. These indices characterize resources that the attacker needs to compromise to conduct a perfectly undetectable attack against each actuator. We propose methods to compute the actuator security indices, show that the defender can improve the indices by allocating additional sensors, and discuss the robustness of the indices. We also study a sensor allocation game based on actuator security indices. The goal of studying this game is to develop a monitoring strategy that improves the indices. We derive an approximate Nash Equilibrium of the game, and present the cases when this approximate Nash Equilibrium becomes exact. We also outline the intuition behind this equilibrium, and discuss the ways to further improve the monitoring strategy from the equilibrium.

  • Olayinka, Benjamin
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Rapid Estimation of Energy Consumption for Embedded Software2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Energy consumption is an important parameter very early in the design phase for embedded systems, especially battery powered systems. To obtain a cycle-accurate estimation of a program’s energy consumption, the program must be compiled and simulated on the target architecture, but this requires a hardware specification and complete code which may not be available early in the design phase. Simulation is computationally and time intensive, and simulation must be done with proprietary tools for some hardware platforms.

    Previous work has investigated instruction-level power models for embedded systems, and other work has extended this to source code power analysis tools for RISC processors with near constant instantaneous power consumption per instruction, but no work has examined the effectiveness of source code estimation techniques on modern digital signal processing units with non-constant power consumption which varies per instruction.

    This thesis proposes and evaluates a technique for source code estimation of power and energy consumption on an Analog Devices Blackfin BF70x DSP, and compares this technique to other power estimation techniques realizable at different stages of the design cycle. The proposed method is also made available as an extension for the pure-python, open source Lizard code analysis tool, and the method can easily be extended for other processors.

    This Lizard based source code power estimation tool is directed at the use case in which machine generated programs must be evaluated for energy efficiency, and excels in the case where:

    1. Speed of estimation is more important than absolute accuracy

    2. Not all source code dependencies are available (compilation may not be possible at this stage)

  • Pacini, Rocco Anthony
    KTH, School of Architecture and the Built Environment (ABE), Architecture.
    Post-Industrial infrastructure: re-imagined spaces of form2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Thesis project; 'Post-Industrial infrastructure: re-imagined spaces of form' revolves around several important issues regarding the treatment, appreciation/non-appreciation and architectural qualities of abandon Post-Industrial sites. As many of these types of sites offer many fine qualities that I find valuable within the architectural construct. Furthermore, Post-Industrial sites offer an array of established infrastructure(s) e..g buildings, lots of space, high ceilings, lots of windows, natural light as well as connectivity and accessibility to the urban environment. I decided to study an abandoned site in Newark, New Jersey USA. The site had be shuttered since 1990 and is/was in very poor condition. A formal chemical company that was owned an operated by Maas & Waldstein Chemical Company. The main theme of the thesis was to remediate the contaminated site as well as re-purposed three remaining brick structures. As to re-imagine and re-generate the entire site with pathways, flower gardens, Zen-huts for sitting, relaxing and contemplation. There is also a tree mall with a walking paths that guide you around the site, lots of trees and a bee-coup area to help with the pollination of the large array of flowerbeds, a Post-Industrial walking park. As for the structures, each structure was designated in accordance with its condition. All three of the structures were salvageable, the Enamel building is to become an exhibition/gallery space with artisan lofts on the second and third floors. The Laboratory building will house a café with a nice sized sitting area as well as a small seminar area opposite the café. The second floor will become an office space for the administrators of the site. The third and final building is called the Lacquer building which is in very poor condition but it was saved and converted into a ruin-park. I kept the integrity of  the 'ruin' as natural as possible. As for the interior, an array of flowerbeds, sitting benches and a small sitting/tea-room to enjoy a tea/coffee etc. is an excellent addition to the structure. Of note, the entire roof infrastructure had been totally destroyed over time, creating prefect conditions for the inner-park concept.  The structure also needed to be stabilized with an iron exo-structure which has a two-fold design element, one being to stabilize the integrity of brickwork and the second being to create open air canopy, giving the inner space a more comfortable, dynamic atmosphere, additionally it also adds and architectural element and quality to the existing structure. To summarize, the project became very complex due to discovery and complexities of the contamination which added a fair amount dedicated research time to the project. The highlights of the project are the very detailed site plan as wells as the Lacquer building i.e. Ruin-Park and exo-structure as well as the Thinner building park (see the site plan) wooden planked pathway through the remediation flowerbeds. Over the course of the project, all three designs became the flagship(s) of the project. 

  • Fernandez, Leon
    KTH, School of Electrical Engineering and Computer Science (EECS).
    FPGA Co-Processing in Software-Defined Radios2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The Internet of Things holds great promises for the future. In the smart cities of tomorrow, wireless connectivity of everyday objects is deemed essential in ensuring efficient and sustainable use of vital, yet limited resources such as water, electricity and food. However, radio communication at the required scale does not come easily. Bandwidth is yet another limited resource that must be used efficiently so that wireless infrastructure for different IoT applications can coexist. Keeping up with the digitalization of modern society is difficult for wireless researchers and developers. The Software-Defined Radio (SDR) is a technology that allows swift prototyping and development of wireless systems by moving traditional hardware-based radio building blocks into the software domain. For developers looking to be on the bleeding edge of wireless technology, and thus keep up with the rapid digitalization, the SDR is a must. Many SDR systems consist of a radio peripheral that handles tasks such as amplification, AD/DA-conversion and resampling that are common to all wireless communication systems. The application-specific work is done in software at the baseband or an intermediate frequency by a host PC connected to the peripheral. That may include PHY-related processing such as the use of a specific modulation scheme as well as higher-layer tasks such as switching. While this setup does provide great flexibility and ease-of-use, it is not without its drawbacks. Many communication protocols specify a so-called round-trip time and devices wishing to adhere to the protocol must be able to respond to any transmission within that time. The link between the host and the peripheral is a major cause of latency and limits the use of many software-defined radio systems to proof-of-concept implementations and early prototyping since it prevents the round-trip time from being fulfilled. Overcoming the latency in the link would allow the flexibility of SDRs to be brought into field applications.This thesis aims to offload the link between the host PC and the radio peripheral in a typical SDR system. Selected parts IEEE 802.15.4, a wireless standard designed for IoT applications, were implemented by using unused programmable logic aboard the peripheral as a co-processor in order to reduce the amount of data that gets sent on the link. Frame success rate and round-trip time measurements were made and compared to measurements from a reference design without any co-processing in the radio peripheral. The co-processing greatly reduced traffic on the link while achieving a similar frame success rate as the reference design. In terms of round-trip time, the co-processing actually caused the latency to increase. Furthermore, the measurements from the coprocessing system showed a counter-intuitive behavior where the round-trip time decreased as the rate of the generated test frames increased. This unusual behavior is most likely due to internal buffer mechanisms of the operating system on the host PC. Further investigation is required in order to bring down the response time to a level more suitable for field applications.

  • Perini, Massimo
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Dynamic Graph Embedding on Event Streams with Apache Flink2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Graphs are often considered an excellent way of modeling complex real-world problems since they allow to capture relationships between items. Because of their ubiquity, graph embedding techniques have occupied research groups, seeking how vertices can be encoded into a low-dimensional latent space, useful to then perform machine learning. Recently Graph Neural Networks (GNN) have dominated the space of embeddings generation due to their inherent ability to encode latent node dependencies. Moreover, the newly introduced Inductive Graph Neural Networks gained much popularity for inductively learning and representing node embeddings through neighborhood aggregate measures. Even when an entirely new node, unseen during training, appears in the graph, it can still be properly represented by its neighboring nodes. Although this approach appears suitable for dynamic graphs, available systems and training methodologies are agnostic of dynamicity and solely rely on re-processing full graph snapshots in batches, an approach that has been criticized for its high computational costs. This work provides a thorough solution to this particular problem via an efficient prioritybased method for selecting rehearsed samples that guarantees low complexity and high accuracy. Finally, a data-parallel inference method has been evaluated at scale using Apache Flink, a data stream processor for real-time predictions on high volume graph data streams.

  • Zheng, Shuo
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Mobile Network performance analysis of UAV: A Simulation for UAVs utilizing 4G-LTE cellular networks2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The usage of UAVs (Unmanned Aircraft Vehicle) is soaring, not just for hobbyists but increasingly for a range of professional and civil applications. Some of the more sophisticated applications that have high data usage and long-range flight requirements are being developed now. The range and capability of typical wireless connectivity technologies are not enough for such applications.

    Connecting UAVs to the mobile network is a solution. There are lots of benefits which mobile network can provide for UAVs and UTM (Unmanned Aircraft System Traffic Management). However, the anticipation of UAVs was not considered at first in network planning, which creates unexpected coverage conditions. The introduction of UAVs impacts LTE (Long Term Evolution) network in several ways and the network coverage and capacity of UAVs at low altitude is significantly different from that of terrestrial UEs. The thesis work includes investigation about how UAVs impact LTE network and how mobile network coverage and capacity for UAVs change when other factor changes. The impact of methods to enhance the mobile network for UAVs would also part of the research. In this work, a successful simulation in order to investigate UAV’s situation while using 4G LTE cellular networks is developed. In order to properly test the developed framework for a range of different inputs, various generic scenarios were successfully developed and executed. Using this simulation, we have shown that UAV’s network situation is affected by 2 parameters: the height of UAV and the load of the eNodeBs (Evolved Node B). We have successfully demonstrated that UAV at higher attitude may cause more serious network condition in the suburban area compared with the case in the urban area. Finally, an interference mitigation technique: antenna beam selection is applied and tested. We show that it can improve the network condition for UAV at a higher altitude. Some improvements to the model could be a modeling of inter-cell interference and multipath effects. Models of weather condition in UAV’s flying space would also greatly improve the framework. Besides a scheme for modulation and bit error calculation could be used to build a more generic model. In the thesis, antenna propagation and gain models are not perfect, so more accurate model would also be a great improvement. Only antenna beam selection is tested in this thesis and the implementation does not include antenna mechanical design and model building. For further research, more methods like interference cancellation, power control and inter-cell interference coordination can be tested in both simulation and hardware.

  • Lagerqvist, Simon
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Aghadai Ghaderi, Dariush
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Implementation of the communication between SiC, Piezo-LEGS and On-board Computer2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis presents the work of adding support for a communications protocol in a space application. The work is a part of KTHs MIST (MIniature STudent Satellite) project which aims at sending an experimental satellite into space. Each experiment on the satellite is designed as a subsystem. These subsystems need to be able to communicate with the main computer on the satellite in order to transfer the results of the experiments down to earth. In efforts prior to the current thesis, a special communications protocol has been specified to solve this problem. That protocol is called MSP (MIST Space Protocol). This paper describes the efforts to add support for MSP to two of the satellite’s experiments. These two experiments are called SiC in Space and Piezo-LEGS. However, since Piezo-LEGS is incompatible with the I2C bus in which MSP runs on top of, it must communicate through the SiC experiment. Which parts of the protocol that need to be supported by each experiment are defined. The result of the work is that the experiments can communicate with the main computer through the MSP protocol.

  • Orunkara Poyil, Harilal
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Time series Forecasting Incorporating Exogenous Information2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The discussions on social media platforms reflect the views of masses on different ongoing long term events. The demand for different people-oriented services observes upsurge during the period of such long term events. Accurate forecasting of such time series data has a vital role in many business domains. In this project, we propose two deep learning based architectures for time series forecasting which incorporate exogenous information available from social media in both textual and numerical modalities. Our experiments show that compared to forecasting without exogenous information, adding numerical attributes yields approximately 1% increment in the forecasting accuracy while textual information causes a 6-9% reduction in the accuracy Our assumption on the result is that the collected exogenous data especially the textual information is insufficient in this problem context. Adding more related data from the same or multiple sources may improve the forecasting performance.

  • Lundgren, Tony
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Modeling Shared Memory Access in a SystemC/TLM-based Many-core Virtual Platform2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The market for embedded devices is fast paced and is growing quickly. To be competitive, time-to-market is important for new products. To shorten the time it takes to release new products, hardware simulators in the form of virtual platforms are developed to allow software development to start before hardware is available.

    Virtual platforms model hardware at a high abstraction level, ideally a virtual platform should be as simple as possible, with functionally correct models of the hardware, but to allow complex software to run some timing must be modeled as well. The more timing that is modeled the more complicated the virtual platform becomes. This can make the virtual platform more prone to bugs. It can result in software that is sensitive to changes in the virtual platform if software is developed depending on the modeled timing. Modeling too much timing can also make the virtual platform too slow to run large programs.

    This thesis investigates how accesses to shared memory resources are modeled in a virtual platform using SystemC, compared to the the many-core system it emulates. This SystemC simulation uses many SystemC processes, and frequently switch between the processes. A tool to visualize these switches between SystemC processes is developed.

    Changes are implemented to reduce context switching between SystemC processes. Reducing context switching is good because each switch has some penalty in performance because of the overhead invoking the SystemC kernel, fewer context switches also mean SystemC processes are synchronizing less often which makes it possible to gain performance by running multiple SystemC processes in parallel.

    These changes are evaluated running production software tests. The results show that the changes reduce context switching by 94% for one test program, and reduce the total run time for the same program by 16% on average. Though one of 159 software tests fail with the changes, the simplifications of the virtual platform in this thesis show the potential benefits of a simpler simulation model.

  • Granath Hansson, Anna
    KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management.
    En social bostadssektor i Sverige?2020Report (Other (popular science, discussion, etc.))
  • Toutounji Alkallas, Adnan
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Building Distributed Systems for Fresh and Low-latency Data Delivery for Internet of Things2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Internet of Things (IoT) is a system of interrelated computing devices with the ability to transfer data over the network and collected by the applications that rely on fresh information, where the freshness of data can be measured by a metric called Age of Information (AoI). Age of Information is the time that is measured by the receiving node from the time the data has generated at the source. It is an important metric for many IoT applications such as, collecting data from temperature sensors, pollution rates in a specific city. However, the bottleneck problem occurs at sensors because they are constrained devices in terms of energy (power via battery), and also have limited memory and computational power. Therefore, they cannot serve many requests at the same time and thus, it will decrease the information quality which means more unnecessary aging. As a result, we suggest as a solution a distributed system that takes into account the AoI transmitted by the sensors so that IoT applications will receive the expected information quality.

    This thesis describes the three algorithms that can be used tobuild and test three different topologies. The first algorithm builds a Random graph while second and thirds algorithms shapes Clustered and Hybrid graphs respectively.

    For testing, we use Python based SimPy package which is a process-based discrete-event simulation framework. Finally, we compare Random, Clustered and Hybrid graphs results. Overall, the Hybrid graph delivers more fresh information than other graphs.

  • Boopathi, Vidhyarthi
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Scalable Gaussian Process Regression for Time Series Modelling2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Machine learning algorithms has its applications in almost all areas of our daily lives. This is mainly due to its ability to learn complex patterns and insights from massive datasets. With the increase in the data at a high rate, it is becoming necessary that the algorithms are resource-efficient and scalable. Gaussian processes are one of the efficient techniques in non linear modelling, but has limited practical applications due to its computational complexity. This thesis studies how parallelism techniques can be applied to optimize performance of Gaussian process regression and empirically assesses parallel learning of a sequential GP and a distributed Gaussian Process Regression algorithm with Random Projection approximation implemented in SPARK framework. These techniques were tested on the dataset provided by Volvo Cars. From the experiments, it is shown that training the GP model with 45k records or 219 ≈106 data points takes less than 30 minutes on a spark cluster with 8 nodes. With sufficient computing resources these algorithms can handle arbitrarily large datasets.

  • Kourinnoi, Bogdan
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Nyckelfaktorer för Grön Innovation inom Bygg- och Anläggningssektorn2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The construction industry accounts for a major part of Sweden’s overall carbon dioxide emissions, and is because of that, today facing significant challenges in its aim to mitigate the industry’s total climate impact. During the coming decade, the Swedish infrastructure construction industry must find solutions that can mitigate its carbon dioxide emissions by 50 per cent. This means that contractors will have to find ways to efficiently implement both existing and innovative solutions. This master’s thesis has researched which key factors apply for successful implementation of green solutions at infrastructure development. As a case study, the implementation of the product Multicem at two of Skanska’s developments was researched. Multicem is a product that can be used in dry deep mixing in order to limit carbon emissions. The case study, together with literature and interviews, provided conclusions on which factors are relevant for successful implementation of solutions that result in less carbon dioxide emissions.

    The research shows that a project’s capacity to mitigate its emissions is decided by projectspecific, organisational and sectorial factors, and is limited by the construction industry’s project-based characteristics. The study shows that key aspects on a project-level are that the solutions ought to be introduced during an early phase, be economically beneficial and also be implemented easily through standardised working routines. Additionally, earlier experiences must be spread efficiently within the organization so that internal knowledge can be accessible for new developments. Organisational key factors for successful green innovation are: engaged managerial personnel and cooperation between different companies and developments.

    The results from this master’s thesis show that the construction industry is dependent on that climate change mitigation efforts are taken within the whole industry. In order to develop beneficial solutions and methods, contractors are reliant on that the entire supply chain work towards green innovation. Additionally, the Swedish Transport Administration’s role when designing contracts and legislation is of the outmost importance, since it as an authority regulates the work contractors and consultants perform.

  • Nazir, Shareq Mohd
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Energy Processes.
    Cloete, Jan Hendrik
    SINTEF Industry.
    Cloete, Schalk
    SINTEF Industry.
    Amini, Shahriar
    Norwegian University of Science and Technology.
    Pathways to low-cost clean hydrogen production with gas switching reforming2020In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487Article in journal (Refereed)
    Abstract [en]

    Gas switching reforming (GSR) is a promising technology for natural gas reforming with inherent CO2 capture. Like conventional steam methane reforming (SMR), GSR can be integrated with water-gas shift and pressure swing adsorption units for pure hydrogen production. The resulting GSR-H2 process concept was techno-economically assessed in this study. Results showed that GSR-H2 can achieve 96% CO2 capture at a CO2 avoidance cost of 15 $/ton (including CO2 transport and storage). Most components of the GSR-H2 process are proven technologies, but long-term oxygen carrier stability presents an important technical uncertainty that can adversely affect competitiveness when the material lifetime drops below one year. Relative to the SMR benchmark, GSR-H2 replaces some fuel consumption with electricity consumption, making it more suitable to regions with higher natural gas prices and lower electricity prices. Some minor alterations to the process configuration can adjust the balance between fuel and electricity consumption to match local market conditions. The most attractive commercialization pathway for the GSR-H2 technology is initial construction without CO2 capture, followed by simple retrofitting for CO2 capture when CO2 taxes rise, and CO2 transport and storage infrastructure becomes available. These features make the GSR-H2 technology robust to almost any future energy market scenario.

  • Zhang, Hongyi
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Efficient learning on high-dimensional operational data2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In a networked system, operational data collected by sensors or extracted from system logs can be used for target performance prediction, anomaly detection, etc. However, the number of metrics collected from a networked system is very large and usually can reach about 106 for a medium-sized system. This project aims to analyze and compare different unsupervised machine learning methods such as Unsupervised Feature Selection, Principle Component Analysis, Autoencoder, which can lead to efficient learning from high-dimensional data. The objective is to reduce the dimensionality of the input space while maintaining the prediction performance when compared with the learning on the full feature space. The data used in this project is collected from a KTH testbed which runs a Video-on-Demand service and a Key-Value store under different types of traffic load. The findings confirm the manifold hypothesis, which states that real-world high-dimensional data lie on lowdimensional manifolds embedded within the high-dimensional space. In addition, this project investigates data visualization of infrastructure measurements through two-dimensional plots. The results show that we can achieve data separation by using different mapping methods.

  • Asplund, Fredrik
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Mechatronics. KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Holland, Greg
    Rolls-Royce plc.
    Odeh, Saleh
    Rolls-Royce plc.
    Conflict as software levels diversify: Tactical elimination or strategic transformation of practice?2020In: Safety Science, ISSN 0925-7535, E-ISSN 1879-1042, Vol. 126, article id 104682Article in journal (Refereed)
    Abstract [en]

    Communities of Practice create a shared consensus on practice. Standards defining software levels enable firms to diversify practice based on a software component’s contribution to potential failure conditions. When industrial trends increase the importance of lower software levels, there is a risk that the consensus on practice for software engineers used to primarily working at higher levels of assurance is eroded. This study investigates whether this might lead to conflict and – if so – where this conflict will materialize, what the nature of it is and what it implies for safety management.

    A critical case study was conducted: 33 engineers were interviewed in two rounds. The study identified a disagreement between designers with different roles. Those involved in the day-to-day activities of software development advocated elimination of practice (dropping or doing parts less stringently), while those involved in expert advice and process planning suggested transforming practice (adopting realistic alternatives).

    This study contributes to practice by showing that this conflict has different implications for firms that do not lead vs those that lead the early adoption of technology. At the majority of firms, safety management might need to support the organisation of informal opinion leaders to avoid vulnerability. At early adopters, crowdsourcing could provide much-needed help to refine the understanding of new practice. Across entire industries, crowdsourcing could also benefit entire engineering standardization processes. The study contributes to theory by showing how less prescriptive standardization in the context of engineering does not automatically shift rulemaking towards allowing engineers to act more autonomously.

  • Kjellberg Skjenken, Martin
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Artificial Groundwater Injection: A Study of Groundwater Level Control in Swedish Infrastructure Projects2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis sets out to increase the knowledge of artificial groundwater injection (AGWI) in Sweden on behalf of the Swedish Transport Administration. This has been done by firstly conducting a literature review which provided the background which comprises mainly groundwater theory and subsidence. Then several methods were utilized; Interviews, cost analysis, case studies and a simplistic numerical modelling in order to obtain an overall understanding of the AGWI facilities. The interviews provide in-depth knowledge of how the techniqueis handled in different industry contexts. The cost analysis provided with an understanding of the economic relations for an AGWI facility. The case studies provided generalizability and knowledge in how the AGWI is conducted in real projects. Finally, the numerical model provided with knowledge of how a can be developed and what interesting information it can and should contain. The results showed that the AGWI as a subsidence mitigation technique have been developed and is now a subject of increased focus and demand from the legislator and designer perspective, but not the STA. The results show as well that we can expect changed preconditions both geographically and temporally varying, for the AGWI and therefor a change in how the AGWI is handled by the STA is recommended to change. Another result was that the cost analysis showed that the common idea of tap-water is a cheaper alternative than re-injecting the leaked water back to the tunnel is debatable, even false. The case studies showed that the most common water utilization was tap water and that only a few facilities has re-injection capabilities. The STA is recommended to increased their focus on the AGWI technique, to plan for a long term operation and maintenance perspective and to demand calculations of the AGWI costs in relation to water use and the facilities sustainability with the view on future estimated climate change.

  • Farshin, Alireza
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Computer Science, Communication Systems, CoS, Network Systems Laboratory (NS Lab).
    Roozbeh, Amir
    KTH, School of Electrical Engineering and Computer Science (EECS), Computer Science, Communication Systems, CoS, Network Systems Laboratory (NS Lab). Ericsson Research.
    Maguire Jr., Gerald Q.
    KTH, Superseded Departments (pre-2005), Microelectronics and Information Technology, IMIT. KTH, Superseded Departments (pre-2005), Teleinformatics. KTH, Superseded Departments (pre-2005), Wireless at KTH. KTH, School of Electrical Engineering and Computer Science (EECS), Computer Science, Communication Systems, CoS.
    Kostic, Dejan
    KTH, School of Electrical Engineering and Computer Science (EECS), Computer Science, Communication Systems, CoS, Network Systems Laboratory (NS Lab).
    Make the Most out of Last Level Cache in Intel Processors2019In: Proceedings of the Fourteenth EuroSys Conference (EuroSys'19), Dresden, Germany, 25-28 March 2019., 2019Conference paper (Refereed)
  • Skalli, Anas
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Hybrid integration of hBN quantum sources in SiN photonic circuits2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • Lundberg, Fabian
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Membrane Fabrication by Dry Silicon Etching for X-ray Optics2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • Everitt, Carl-Magnus
    KTH, School of Engineering Sciences (SCI), Solid Mechanics (Dept.), Solid Mechanics (Div.). KTH - Royal institute of technology.
    Influence of surface roughness on rolling contact fatigue considering thermal elastohydrodynamic lubrication effects: Due to Corona it is not possible to attend this defense in person, instead attend via this link: https://play.kth.se/media/0_omfsppe62020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Rolling contacts are utilized in many technical applications, both in bearings and in the contacts between gear teeth. These components are subjected to high loads in many of their applications. The high loads causes very high contact pressures which may cause rolling contact fatigue, often denoted as pitting or spalling. This work focuses on the rolling contact fatigue mechanism of surface initiated pitting. Detailed simulations and experiments of rolling contacts have been performed in order to attain a better understanding of why pitting initiates and grows. The contact between two gears in a truck retarder was used as a case study. The investigated contact experienced elastohydrodynamic lubrication, EHL, conditions at which multiple pitting damages arose.

    Results from numerical investigations are presented in the papers A-C. In Paper A a numerical analysis of different measured surface topographies is presented showing that the sliding direction explains why more damage initiated down in the dedendum than up in the addendum. Detailed results of single artificial defects are presented in Paper B in order to explain the difference seen in Paper A. The results show that the defects subjected to negative slip break through the lubricant more and were thus subjected to higher friction. The analysis was extended to the conditions of the pitch line in Paper C and included variations of pressure, defect sizes, choice of lubricant and operational temperatures. The results presented in Paper C shows that the underlying theories of the asperity point load mechanism also predicts damage initiation at pure rolling, which agrees with the experiments on the truck retarder.

    A new imprint method for the manufacturing of well-defined micrometre high asperities in the surface of discs is presented in Paper D. The method was developed in order to enable experimental investigations of rolling contact fatigue. The manufactured asperities showed the potential to survive more than 35 million load cycles when tested in a twin-disc machine.

    An experimental and numerical investigation of micrometre high artificial asperities created with the imprint method is presented in Paper E. The experimental results showed that micro-pits developed on the leading edge of the highest asperities. The comparison with numerical simulations showed that the plastic deformations occurring during run-in there caused high tensile residual stresses in this region. Rolling contact fatigue, RCF, cracks initiated behind the trailing edge of the indents in the experiments. The simulations of the continued EHL testing, showed that these loads cased high tensile stresses in this region. The conclusion was hence drawn that the micro pits were caused by the residual stresses while the EHL loads caused the initiations of the RCF cracks.

  • Du Preez, Rose
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.).
    Internal brand management in South African contact centers2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Globally contact centers are ubiquitous in medium to large organizations operating in both B2B and B2C service industries. Frontline staff working in contact centers represent a major component of the way in which customers experience service organizations’ brands.

    There is a paucity of research on marketing in contact centers. Internal brand management is acknowledged as being difficult to implement, this could be exacerbated if an organization outsources their contact center operations. This presents a research gap as contact centers represent an important medium through which customers experience a service brand.

    The overall research question in this thesis is:

    Are extant theoretical models for internal brand management applicable to frontline employees in contact centers?

    The overall research question is subdivided into the following research questions:

    RQ1: What are managers’ practices and experiences of internal brand management in contact centers?

    RQ2:  Do current theoretical models of internal brand management adequately explain the behavioral consequences among frontline employees in contact centers?

    RQ3: What are the implications of outsourcing contact centers for internal brand management?

    The overall contribution of this thesis is that evidence indicates that extant theoretical models of internal brand management are not applicable to frontline employees in contact centers. Paper 1 reveals that managers are unfamiliar with the theoretical models and practices of internal brand management, furthermore, they face numerous barriers and obstacles with implementation. Paper 2 provides the first direct evidence of internal brand management affecting job satisfaction, and the inclusion of job satisfaction improves a theoretical internal brand management model. Paper 3 develops and tests a model which includes job satisfaction, and two behavioral consequences viz. intention to stay and brand citizenship behavior. This paper reveals that the drivers of internal brand management are organization-specific. Paper 4 demonstrates that the dominant experience of contact center outsourcing is negative, and organizations which outsource tend to lose control of internal brand management and the customers’ brand experience.

  • Kapoor, Aman
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Jayagopal, Nishka Rani
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Sustainable Buildings.
    Vandalism and social capital: A case study of Hovsjö, Södertälje2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Vandalism is a form of a crime and threatens the safety and unity of a neighborhood. To inspect the issues of vandalism, a case study of Hovsjö in Södertälje is chosen. The area has most immigrants mainly from the Middle Eastern descent. Attempt is made to investigate these issues of vandalism with the help of theory, public documents of the area, history, physical evidence using photographs and conducting interviews of the residents and the authority. The issues of vandalism upon thorough analysis are found to be very subjective and are open to different interpretations. Thus, this thesis is about the authors’ version of interpreting the issue as immigrants from India. One of the key findings from the study is that there is a clear lack of trust between the authorities and the residents of Hovsjö. The reasons for this lack of trust is due to many issues but mostly revolve around the integration of the immigrants into the Swedish society. Thus, few ideas are recommended as an attempt to encourage better integration of immigrants into the Swedish Society and other generic ideas to prevent vandalism and increase the social capital. These ideas include ‘earliest is best’, ‘one size does not fit all’, ‘break the ice’, ‘get the right mix’ etc. among others.

  • Dahlberg, Magnus
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Modelling of aquifer on Ingarö island: A Steady-State model2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Värmdö municipality, in the archipelago of Stockholm, has one of Sweden’s fastest growing populations and is a popular location for tourism and summer houses. This puts a lot of pressure on groundwater reservoirs and will likely be even more strained in the future as the climate continues to heat up due to anthropogenic activities. The aim of this study is to investigate the use of groundwater resources on the island of Ingarö, today and in a changing climate. The goal was also to identify the behaviour of the groundwater reservoir under different extraction rates. A model was constructed using MODFLOW, a software developed and maintained by the U.S. Geological Survey. The results show that for the present-day scenario with the current extraction rate there is a surplus of recharge leaving the reservoir. Moreover, three groundwater divides could be identified in the reservoir which can prove useful when examining the movement of contaminants. The result also indicated that an extraction rate of 105% of current extractions could be possible without any artificial infiltration. At an extraction rate of 110%, one well struggled with keeping up with demand for water. As the extraction rate increased further the results were deemed as inconclusive. For these scenarios, model domain required to be extended further east due to a constant head boundary condition acting as an infinite source of water in these cases.

  • Neromylioti, Theodora
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Estimating the probability of levee failure for flood risk mapping: An application to Paglia River2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Climate change results to more extreme and frequent flood events that induce extra risk to flood protection structures such as levees. Thus, estimation of the probability of levee failure is of utmost importance when it comes to structural safety and flood risk assessment. This master thesis focuses on the estimation of the probability of levee failure owing to backward erosion at the foundation of the levee. For the estimation of the probability of failure three breach models of different complexity were developed and site-specified data were used from the Paglia river area and an assessment of the results followed. Besides the breach models, a 2-D hydraulic model was also built where breach scenarios were used to assess the associated flood risk. The results showed that the complexity of the breach model plays significant role to the estimated probability of failure. The simplest model estimated the lowest probability, while the complex the highest. Consequently, the associated to the complex model flood risk was higher than the other two.