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  • 1.
    Abd Alwaheb, Sofia
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Implementering DevSecOps metodik vid systemutveckling för hälso och sjukvård2023Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Inom hälso- och sjukvården är IT-säkerhet avgörande för att skydda både personlig information och patientsäkerheten. För närvarande genomförs implementering av säkerhetsåtgärder och tester efter mjukvaruutvecklingen, vilket kan minska effektiviteten och utgöra en potentiell risk för patienternas integritet. Detta arbete undersökte implementeringen av DevSecOps-metodiken inom hälso- och sjukvården med fokus på utvecklingsfasen. Genom att intervjua anställda och använda säkerhetsverktyg som SAST, kodgranskning, penetrationstestning och DAST identifierades fördelar och utmaningar. Utmaningarna inkluderade brist på säkerhetskunskap och svårighet att integrera verktyg kostnadsfritt. Trots detta visade resultatet på möjligheten att förbättra säkerheten, effektivisera arbetet och spara pengar genom att använda gratis verktyg och implementera säkerhet redan i utvecklingsfasen. Utbildning och anställning av säkerhetskompetent personal betonades också som viktigt för att upprätthålla höga säkerhetsstandarder

    Fulltekst (pdf)
    fulltext
  • 2.
    Abdi Dahir, Najiib
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Dahir Ali, Ikran
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Privacy preserving data access mechanism for health data2023Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [en]

    Due to the rise of digitalization and the growing amount of data, ensuring the integrity and security of patient data has become increasingly vital within the healthcare industry, which has traditionally managed substantial quantities of sensitive patient and personal information. This bachelor's thesis focused on designing and implementing a secure data sharing infrastructure to protect the integrity and confidentiality of patient data. Synthetic data was used to enable access for researchers and students in regulated environments without compromising patient privacy. The project successfully achieved its goals by evaluating different privacy-preserving mechanisms and developing a machine learning-based application to demonstrate the functionality of the secure data sharing infrastructure. Despite some challenges, the chosen algorithms showed promising results in terms of privacy preservation and statistical similarity. Ultimately, the use of synthetic data can promote fair decision-making processes and contribute to secure data sharing practices in the healthcare industry.

    Fulltekst (pdf)
    Examensarbete
  • 3.
    Abdollahi, Meisam
    et al.
    Iran Univ Sci & Technol, Tehran, Iran..
    Baharloo, Mohammad
    Inst Res Fundamental Sci IPM, Tehran, Iran..
    Shokouhinia, Fateme
    Amirkabir Univ Technol, Tehran, Iran..
    Ebrahimi, Masoumeh
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elektronik och inbyggda system, Elektronik och inbyggda system.
    RAP-NoC: Reliability Assessment of Photonic Network-on-Chips, A simulator2021Inngår i: Proceedings of the 8th ACM international conference on nanoscale computing and communication (ACM NANOCOM 2021), Association for Computing Machinery (ACM) , 2021Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Nowadays, optical network-on-chip is accepted as a promising alternative solution for traditional electrical interconnects due to lower transmission delay and power consumption as well as considerable high data bandwidth. However, silicon photonics struggles with some particular challenges that threaten the reliability of the data transmission process.The most important challenges can be considered as temperature fluctuation, process variation, aging, crosstalk noise, and insertion loss. Although several attempts have been made to investigate the effect of these issues on the reliability of optical network-on-chip, none of them modeled the reliability of photonic network-on-chip in a system-level approach based on basic element failure rate. In this paper, an analytical model-based simulator, called Reliability Assessment of Photonic Network-on-Chips (RAP-NoC), is proposed to evaluate the reliability of different 2D optical network-on-chip architectures and data traffic. The experimental results show that, in general, Mesh topology is more reliable than Torus considering the same size. Increasing the reliability of Microring Resonator (MR) has a more significant impact on the reliability of an optical router rather than a network.

  • 4.
    Abdulnoor, John
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Gawriyeh, Ramy
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    A study of methods to synchronize different sensors between two smartphones2021Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [en]

    Obtaining data simultaneously from different sensors located on different mobile devices can be useful for applications such as sports and medicine. In order for the data from the different sensors to be combined for analysis, the mobile devices need to be time synchronized first. This paper presents an application that can be used to calculate the difference between the internal clocks of two android devices using a combination of the Cristian and Marzullo algorithms. Different methods to connect the devices over Wi-Fi as well as the internet are tested to determine the optimal method for clock synchronization. The paper also validates the synchronization by testing different sensors on two identical android smartphones. The results show that clock synchronization between two mobile devices can be achieved with a round-trip time of 2 milliseconds or less using Wi-Fi Direct. Validation of the synchronization shows that a delay of 7 milliseconds or less can be achieved between two sensors of the same type on two identical android smartphones. It also shows that the least achievable delay between sensors of different types is 16 milliseconds. The conclusion is that once two android smartphones’ clocks are synchronized, only data from sensors of the same type can be combined, with the exception of the camera sensor. Further testing with more robust equipment is needed in order to eliminate human error which could possibly yield more desirable results.

    Fulltekst (pdf)
    fulltext
  • 5.
    Abebe, Henok Girma
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Filosofi och historia, Filosofi.
    Road Safety Policy in Addis Ababa: A Vision Zero Perspective2022Inngår i: Sustainability, E-ISSN 2071-1050, Vol. 14, nr 9, s. 1-22Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this article, the Addis Ababa city road safety policies are examined and analysed based on the Vision Zero approach to road safety work. Three major policy documents are explored and assessed in terms of how they compare with Vision Zero policy in Sweden, concerning how road safety problems are conceptualised, the responsibility ascriptions promoted, the nature of goal setting concerning road safety objectives, and the specific road safety interventions promoted. It is concluded that there is a big difference between the Swedish Vision Zero approach to road safety work and the Addis Ababa road safety approach in terms of how road safety problems are framed and how responsibility ascriptions are made. In Addis Ababa, policy documents primarily frame road safety problems as individual road user problems and, hence, the responsibility for traffic safety is mainly left to the individual road users. The responsibility extended to other system components such as the vehicles, road design, and the operation of the traffic is growing but still very limited. It is argued that in order to find and secure long-term solutions for traffic safety in the city, a paradigm shift is needed, both regarding what are perceived to be the main causes of road safety problems in the city and who should be responsible for ensuring that road fatalities and injuries are prevented.

    Fulltekst (pdf)
    fulltext
  • 6.
    Adhi, Boma
    et al.
    RIKEN, Ctr Computat Sci R CCS, Wako, Saitama, Japan..
    Cortes, Carlos
    RIKEN, Ctr Computat Sci R CCS, Wako, Saitama, Japan..
    Tan, Yiyu
    RIKEN, Ctr Computat Sci R CCS, Wako, Saitama, Japan..
    Kojima, Takuya
    RIKEN, Ctr Computat Sci R CCS, Wako, Saitama, Japan.;Univ Tokyo, Grad Sch Informat Sci & Technol, Tokyo, Japan..
    Podobas, Artur
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Datavetenskap, Beräkningsvetenskap och beräkningsteknik (CST).
    Sano, Kentaro
    RIKEN, Ctr Computat Sci R CCS, Wako, Saitama, Japan..
    Exploration Framework for Synthesizable CGRAs Targeting HPC: Initial Design and Evaluation2022Inngår i: 2022 IEEE 36Th International Parallel And Distributed Processing Symposium Workshops (IPDPSW 2022), Institute of Electrical and Electronics Engineers (IEEE) , 2022, s. 639-646Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Among the more salient accelerator technologies to continue performance scaling in High-Performance Computing (HPC) are Coarse-Grained Reconfigurable Arrays (CGRAs). However, what benefits CGRAs will bring to HPC workloads and how those benefits will be reaped is an open research question today. In this work, we propose a framework to explore the design space of CGRAs for HPC workloads, which includes a tool flow of compilation and simulation, a CGRA HDL library written in SystemVerilog, and a synthesizable CGRA design as a baseline. Using RTL simulation, we evaluate two well-known computation kernels with the baseline CGRA for multiple different architectural parameters. The simulation results demonstrate both correctness and usefulness of our exploration framework.

  • 7.
    Afzal, Ayesha
    et al.
    Erlangen National High Performance Computing Center (NHR@FAU), 91058, Erlangen, Germany.
    Hager, Georg
    Erlangen National High Performance Computing Center (NHR@FAU), 91058, Erlangen, Germany.
    Wellein, Gerhard
    Erlangen National High Performance Computing Center (NHR@FAU), 91058, Erlangen, Germany; Department of Computer Science, University of Erlangen-Nürnberg, 91058, Erlangen, Germany.
    Markidis, Stefano
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Datavetenskap, Beräkningsvetenskap och beräkningsteknik (CST).
    Exploring Techniques for the Analysis of Spontaneous Asynchronicity in MPI-Parallel Applications2023Inngår i: Parallel Processing and Applied Mathematics - 14th International Conference, PPAM 2022, Revised Selected Papers, Springer Nature , 2023, s. 155-170Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper studies the utility of using data analytics and machine learning techniques for identifying, classifying, and characterizing the dynamics of large-scale parallel (MPI) programs. To this end, we run microbenchmarks and realistic proxy applications with the regular compute-communicate structure on two different supercomputing platforms and choose the per-process performance and MPI time per time step as relevant observables. Using principal component analysis, clustering techniques, correlation functions, and a new “phase space plot,” we show how desynchronization patterns (or lack thereof) can be readily identified from a data set that is much smaller than a full MPI trace. Our methods also lead the way towards a more general classification of parallel program dynamics.

  • 8.
    Ahmed, Olfet
    et al.
    KTH, Skolan för teknik och hälsa (STH), Data- och elektroteknik.
    Saman, Nawar
    KTH, Skolan för teknik och hälsa (STH), Data- och elektroteknik.
    Utvärdering av nätverkssäkerheten på J Bil AB2013Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Detta examensarbete är en utvärdering av nätverkssäkerheten hos J BiL AB, både på social och teknisk nivå. Företaget är beroende av säkra Internet-anslutningar för att nå externa tjänster och interna servrar lokaliserade på olika geografiska platser. Företaget har ingen IT-ansvarig som aktivt underhåller och övervakar nätverket, utan konsulterar ett externt dataföretag. Syftet med examensarbetet är att utvärdera säkerheten, upptäcka brister, ge förbättringsförslag och till viss del implementera lösningar. För att undersöka säkerheten har observationer och intervjuer med personalen gjorts och ett flertal attacker mot nätverket har utförts. Utifrån den data som samlats in kunde slutsatsen dras att företaget har brister vad gäller IT-säkerheten. Framförallt den sociala säkerheten visade sig ha stora luckor vilket till stor del beror på att de anställda varken har blivit utbildade eller fått någon information om hur de ska hantera lösenord, datorer och IT-frågor i allmänt. Förbättringsförslag har getts och viss implementation har genomförts för att eliminera bristerna. De anställda har även med hjälp av en IT-policy och föreläsning blivit utbildade i hur de ska agera och tänka kring IT-relaterade säkerhetsfrågor.

    Fulltekst (pdf)
    Utvärdering av nätverkssäkerheten
  • 9.
    Ahmed, Tanvir Saif
    et al.
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Data- och elektroteknik.
    Markovic, Bratislav
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Data- och elektroteknik.
    Distribuerade datalagringssystem för tjänsteleverantörer: Undersökning av olika användningsfall för distribuerade datalagringssystem2016Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Detta examensarbete handlar om undersökning av tre olika användningsfall inom datalagring; Cold Storage, High Performance Storage och Virtual Machine Storage. Rapporten har som syfte att ge en översikt över kommersiella distribuerade filsystem samt en djupare undersökning av distribuerade filsystem som bygger på öppen källkod och därmed hitta en optimal lösning för dessa användnings-fall. I undersökningen ingick att analysera och jämföra tidigare arbeten där jämförelser mellan pre-standamätningar, dataskydd och kostnader utfördes samt lyfta upp diverse funktionaliteter (snapshotting, multi-tenancy, datadeduplicering, datareplikering) som moderna distribuerade filsy-stem kännetecknas av. Både kommersiella och öppna distribuerade filsystem undersöktes. Även en kostnadsuppskattning för kommersiella och öppna distribuerade filsystem gjordes för att ta reda på lönsamheten för dessa två typer av distribuerat filsystem.Efter att jämförelse och analys av olika tidigare arbeten utfördes, visade sig att det öppna distribue-rade filsystemet Ceph lämpade sig bra som en lösning utifrån kraven som sattes som mål för High Performance Storage och Virtual Machine Storage. Kostnadsuppskattningen visade att det var mer lönsamt att implementera ett öppet distribuerat filsystem. Denna undersökning kan användas som en vägledning vid val mellan olika distribuerade filsystem.

    Fulltekst (pdf)
    FULLTEXT99
  • 10.
    Al Hafiz, Muhammad Ihsan
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Implementation of Bolt Detection and Visual-Inertial Localization Algorithm for Tightening Tool on SoC FPGA2023Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    With the emergence of Industry 4.0, there is a pronounced emphasis on the necessity for enhanced flexibility in assembly processes. In the domain of bolt-tightening, this transition is evident. Tools are now required to navigate a variety of bolts and unpredictable tightening methodologies. Each bolt, possessing distinct tightening parameters, necessitates a specific sequence to prevent issues like bolt cross-talk or unbalanced force.

    This thesis introduces an approach that integrates advanced computing techniques with machine learning to address these challenges in the tightening areas. The primary objective is to offer edge computation for bolt detection and tightening tools' precise localization. It is realized by leveraging visual-inertial data, all encapsulated within a System-on-Chip (SoC) Field Programmable Gate Array (FPGA).

    The chosen approach combines visual information and motion detection, enabling tools to quickly and precisely do the localization of the tool. All the computing is done inside the SoC FPGA. The key element for identifying different bolts is the YOLOv3-Tiny-3L model, run using the Deep-learning Processor Unit (DPU) that is implemented in the FPGA. In parallel, the thesis employs the Error-State

    Extended Kalman Filter (ESEKF) algorithm to fuse the visual and motion data effectively. The ESEKF is accelerated via a full implementation in Register Transfer Level (RTL) in the FPGA fabric.

    We examined the empirical outcomes and found that the visual-inertial localization exhibited a Root Mean Square Error (RMSE) position of 39.69 mm and a standard deviation of 9.9 mm. The precision in orientation determination yields a mean error of 4.8 degrees, offset by a standard deviation of 5.39 degrees. Notably, the entire computational process, from the initial bolt detection to its final localization, is executed in 113.1 milliseconds.

    This thesis articulates the feasibility of executing bolt detection and visual-inertial localization using edge computing within the SoC FPGA framework. The computation trajectory is significantly streamlined by harnessing the adaptability of programmable logic within the FPGA. This evolution signifies a step towards realizing a more adaptable and error-resistant bolt-tightening procedure in industrial areas.

    Fulltekst (pdf)
    fulltext
  • 11.
    Albaloua, Mark
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Kizilkaya, Kenan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Användning av högnivåspråket Swift i webbläsaren och i Android: En studie på möjligheterna att återanvända högnivåspråket Swift utanför iOS i andra plattformar som webbläsare och Android2023Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Syftet med detta arbete var att undersöka möjligheterna att använda högnivåspråket Swift utanför iOS i webbläsaren och i Android. Detta för att minska mängden kod som skrivs och därmed minska utvecklingstiden för att skapa applikationer för iOS, webbläsaren samt Android. För att hitta lämpliga verktyg som löser frågeställningen har en undersökning av tidigare arbeten och metoder gjorts. Resultatet från undersökningen ledde till användningen av ramverket Tokamak tillsammans med WebAssembly för att återanvända Swift i webbläsaren och verktyget SwiftKotlin för att återanvända Swift i Android.

    En applikation med designmönstret Model-View-ViewModel (MVVM) skapades i avsikt att testa återanvändbarheten. Resultatet visade att Tokamak tillsammans med WebAssembly möjliggör återanvändning av ursprungliga koden för iOS-applikationen komplett förutom plattformsspecifika funktioner som lokalt sparande och nätverksanrop. SwiftKotlin möjliggör återanvändning av modellklassen i applikationen med små justeringar, medan vymodell och vyklasserna behöver skrivas manuellt.

    Fulltekst (pdf)
    fulltext
  • 12. Alesii, Roberto
    et al.
    Congiu, Roberto
    Santucci, Fortunato
    Di Marco, Piergiuseppe
    KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Fischione, Carlo
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Architectures and protocols for fast identification in large-scale RFID systems2014Inngår i: ISCCSP 2014 - 2014 6th International Symposium on Communications, Control and Signal Processing, Proceedings, 2014, s. 243-246Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Passive tags based on backscattered signals yield low energy consumption for large-scale applications of RFIDs. In this paper, system architectures and protocol enhancements for fast identifications in ISO/IEC 18000-6C systems that integrate UWB technology are investigated. The anti-collision protocol is studied by considering various tag populations. A novel algorithm is proposed to adapt the UHF air interface parameters with the use of UWB ranging information. The results show that the proposed algorithm yields up to 25% potential performance improvement compared to the ISO/IEC 18000-6C standard.

    Fulltekst (pdf)
    fulltext
  • 13.
    Alevärn, Marcus
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Simplifying Software Testing in Microservice Architectures through Service Dependency Graphs2023Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    A popular architecture for developing large-scale systems is the microservice architecture, which is currently in use by companies such as Amazon, LinkedIn, and Uber. The are many benefits of the microservice architecture with respect to maintainability, resilience, and scalability. However, despite these benefits, the microservice architecture presents its own unique set of challenges, particularly related to software testing. Software testing is exacerbated in the microservice architecture due to its complexity and distributed nature. To mitigate this problem, this project work investigated the use of a graph-based visualization system to simplify the software testing process of microservice systems. More specifically, the role of the visualization system was to provide an analysis platform for identifying the root cause of failing test cases. The developed visualization system was evaluated in a usability test with 22 participants. Each participant was asked to use the visualization system to solve five tasks. The average participant could on average solve 70.9% of the five tasks correctly with an average effort rating of 3.5, on a scale from one to ten. The perceived average satisfaction of the visualization system was 8.0, also on a scale from one to ten. The project work concludes that graph-based visualization systems can simplify the process of identifying the root cause of failing test cases for at least five different error types. The visualization system is an effective analysis tool that enables users to follow communication flows and pinpoint problematic areas. However, the results also show that the visualization system cannot automatically identify the root cause of failing test cases. Manual analysis and an adequate understanding of the microservice system are still necessary.

    Fulltekst (pdf)
    fulltext
  • 14.
    Ali, Umar
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Sulaiman, Rabi
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Using UX design principles for comprehensive data visualisation2023Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [en]

    Workplace safety, particularly in manual handling tasks, is a critical concern that hasbeen increasingly addressed using advanced risk assessment tools. However, pre-senting the complex results of these assessments in an easily digestible format re-mains a challenge. This thesis focused on designing and developing a user-friendlyweb application to visualise risk assessment data effectively. Grounded in a robusttheoretical framework that combines user experience principles, and data visualisa-tion techniques. The study employed an iterative, user-centric design process to de-velop the web application. Multiple visualisation methods, such as pie charts for vis-ualising risk distribution, bar chart, and line chart for time-based analysis, were eval-uated for their effectiveness through usability testing. The application's primary con-tribution lies in its efficient data visualisation techniques, aimed at simplifying com-plex datasets into actionable insights. This work lays the groundwork enabling futuredevelopment by pinpointing areas for improvement like enhanced interactivity andaccessibility.

    Fulltekst (pdf)
    fulltext
  • 15.
    Alkass, Jakob
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    UX spelar roll: Förbättra prestanda hos webbsida för förbättrad användarupplevelse av webbapplikation.2022Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Företaget Telia har en webbapplikation som är under utveckling och ska fungera som en internportal för kunder till företaget. De upplever en bristande prestanda i frontenddelen av applikationen i form av långa laddningstider. De vill därför undersöka möjligheter för optimering av prestandan för deras webbapplikation, i hopp om att förbättra användarupplevelsen. Målet var att undersöka möjligheter för tillämpning av olika optimeringstekniker som kan förbättra delar av prestandan med nära koppling till användarupplevelsen. 

    I detta arbete undersöktes tidigare forskning inom ämnet användarupplevelse relaterat till digitala produkter. Det gjordes även undersökning av liknande arbeten, lämpliga prestandamått och optimeringstekniker. För att testa, analysera och utvärdera optimeringsteknikerna skapades automatiska tester som lagrade mätdata på valda prestandamått. Därefter analyserades mätdata från testerna för att kunna föreslå vidareutveckling för Telias webbapplikation. En analys av mätdata visade en förbättring av Telias webbapplikation för de två undersökta prestandamåtten med 33% respektive 35%.

    Fulltekst (pdf)
    Examensarbete_rapport
  • 16.
    Allamand Moraga, Katarina Viktoria
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Addae, Edmund
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Improvement Model of an established Web Application in the form of a Website (Wikipedia)2023Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    This study promotes the effort of making knowledge accessible to all members of society. The Wikimedia Foundation contributes to this effort through Wikipedia, the free encyclopedia. There is room for improvement of the website that would lead to improved usability, increased number of visitors and with that a greater reach with the knowledge they possess. An investigation has been conducted on the UI of Wikipedia where user friendliness and usability has been the focus. The investigation consisted of two parts, a heuristic evaluation, and user tests. The intended demographic of participants for the user tests were pre-determined, upon selection they were divided into two groups, one consisting of younger subjects with computer experience and the other of older subjects with less computer experience. Participants were asked to first complete a survey, which was then followed by individual interviews. The investigation laid the foundation for the proposal of suggested improvements which would come in the form of a prototype. The developed prototype was then subjected to user tests in order to verify that it in fact was an improved version in comparison with the current (then) UI. Upon completion, the developed prototype could entirely or in part be implemented by Wikipedia to improve user friendliness, increase number of visitors, and consequently the willingness of these visitors to contribute economically to their cause. 

  • 17.
    Alsayfi, Majed S.
    et al.
    King Abdelaziz Univ, Fac Comp & Informat Technol, Dept Comp Sci, Jeddah 21589, Saudi Arabia..
    Dahab, Mohamed Y.
    King Abdelaziz Univ, Fac Comp & Informat Technol, Dept Comp Sci, Jeddah 21589, Saudi Arabia..
    Eassa, Fathy E.
    King Abdelaziz Univ, Fac Comp & Informat Technol, Dept Comp Sci, Jeddah 21589, Saudi Arabia..
    Salama, Reda
    King Abdelaziz Univ, Fac Comp & Informat Technol, Dept Informat Technol, Jeddah 21589, Saudi Arabia..
    Haridi, Seif
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Datavetenskap, Programvaruteknik och datorsystem, SCS.
    Al-Ghamdi, Abdullah S.
    King Abdelaziz Univ, Fac Comp & Informat Technol, Dept Comp Sci, Jeddah 21589, Saudi Arabia.;King Abdelaziz Univ, Fac Comp & Informat Technol, Dept Informat Technol, Jeddah 21589, Saudi Arabia..
    Big Data in Vehicular Cloud Computing: Review, Taxonomy, and Security Challenges2022Inngår i: ELEKTRONIKA IR ELEKTROTECHNIKA, ISSN 1392-1215, Vol. 28, nr 2, s. 59-71Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Modern vehicles equipped with various smart sensors have become a means of transportation and have become a means of collecting, creating, computing, processing, and transferring data while traveling through modern and rural cities. A traditional vehicular ad hoc network (VANET) cannot handle the enormous and complex data that are collected by modern vehicle sensors (e.g., cameras, lidar, and global positioning systems (GPS)) because they require rapid processing, analysis, management, storage, and uploading to trusted national authorities. Furthermore, the integrated VANET with cloud computing presents a new concept, vehicular cloud computing (VCC), which overcomes the limitations of VANET, brings new services and applications to vehicular networks, and generates a massive amount of data compared to the data collected by individual vehicles alone. Therefore, this study explored the importance of big data in VCC. First, we provide an overview of traditional vehicular networks and their limitations. Then we investigate the relationship between VCC and big data, fundamentally focusing on how VCC can generate, transmit, store, upload, and process big data to share it among vehicles on the road. Subsequently, a new taxonomy of big data in VCC was presented. Finally, the security challenges in big data-based VCCs are discussed.

  • 18.
    Altayr, Hydar
    et al.
    KTH, Tidigare Institutioner (före 2005), Data- och systemvetenskap, DSV.
    Adis, Michael
    KTH, Tidigare Institutioner (före 2005), Data- och systemvetenskap, DSV.
    Utveckling och design av WiGID2003Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [en]

    The Center for Genomics and Bioinformatics (CGB) is an academic department at Karolinska Institute. Generally stated, the CGB department is committed to the generation and management of genetic information by approaches aiming at elucidating the connection between genes, protein and function.

    WiGID is a genome information database that is available through WAP (Wireless Application Protocol).

    Our version of WiGID is based on WML, PHP and PostgreSQL as a database server.

    One of the changes on the old WiGID application was the creation of a relational database with seven tables and one view, instead of the file that represented the database on the old version. We also changed the script language from python to PHP.

    The search engine ability has been extended with three new search alternatives for a user to choose from. Each choice leads to other, sometimes multiple choices.

    A GUI has been created for the administrator, to be able to insert information into the database.

    The structure of the search engine is primarily for narrowing down the search result on the phone display, thereby making the search efficient.

    Fulltekst (pdf)
    FULLTEXT01
  • 19.
    Alvaeus, Edvin
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Lindén, Ludvig
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    A comparison of Azure’s Function-as-a-Service and Infrastructure-as-a-Service solutions2023Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Cloud computing is a growing industry. More and more companies are moving away from on-premise infrastructure. Instead, the choice is often to build their systems based on cloud services. This growth in the industry has brought with it new needs and consequently, new solutions. There have never existed as many different cloud providers and services offered by these providers. One of the newer paradigms in this industry is the serverless approach.

    The problem of this thesis is that there is a lack of research into how Azure's serverless Function-as-a-Service offering compare to their more traditional Infrastructure-as-a-Service one. Therefore, the purpose of this work is to compare the two with regards to their performance, cost, and required developer effort. The goal is to provide a comparison that can help software professionals in choosing an appropriate cloud solution for their application. Additionally, it aims to contribute to the increased knowledge of modern serverless solutions while providing a basis for future research.

    A qualitative method supported by measurements is used. The two cloud solutions are compared with regards to their performance, cost and developer effort. This is done by implementing and deploying equivalent Representational State Transfer applications with the two Azure offerings. The two implementations are stress-tested to measure their performance, and their incurred costs are compared. Additionally, the effort involved in developing the two solutions is compared by studying the amount of time required to deploy them, and the amount of code needed for them.

    The results show that the serverless Function-as-a-Service solution performed worse under the types of high loads used in the study. The incurred costs for the performed tests were higher for the serverless option, while the developer effort involved was lower. Additionally, further testing showed that the performance of the Function-as-a-Service solution was highly dependent on the concept of cold starts.

    Fulltekst (pdf)
    fulltext
  • 20.
    Amgren, Pontus
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Olausson, Emil
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Developing Guidelines for Structured Process Data Transfer2023Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Today, society is ever-increasing in its use of technology and computers. The increase in technology creates a need for different programming languages with unique properties. The creation of a system may require multiple languages for multiple processes that need to transfer data between one another. There are several solutions for sharing data between processes with their respective strengths and weaknesses. The differences create a problem of needing to understand the data transfer solutions to use them effectively. This thesis addresses the problem of there not existing any guidelines for data transfer solutions. The purpose is to create guidelines for choosing a data transfer solution. The goal is to help software developers find a data transfer solution that fits their needs. The thesis is meant to inform and contribute to the understanding of possible solutions for sharing data between processes. A literature study and practical study were needed to get that understanding. The literature study was conducted to understand the solutions and to be able to compare them. After that, a practical study was performed to work with the solutions and gain experience. The study was meant to gain measurements for later comparisons of data transfer solutions. The measurements followed the comparative criteria of speed , resource usage , and language support . The result was the creation of guidelines that displayed different scenarios based on the comparative criteria. For each situation, there was a recommendation of solutions that would help in the given situation. These results accomplished the goal and purpose by providing guidelines that could help software developers choose a data transfer solution.

    Fulltekst (pdf)
    fulltext
  • 21. Ananthanarayanan, G.
    et al.
    Ghodsi, Ali
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Programvaruteknik och Datorsystem, SCS. University of California, Berkeley, CA, United States.
    Wang, A.
    Borthakur, D.
    Kandula, S.
    Shenker, S.
    Stoica, I.
    PACMan: Coordinated memory caching for parallel jobs2012Inngår i: Proceedings of NSDI 2012: 9th USENIX Symposium on Networked Systems Design and Implementation, USENIX Association , 2012, s. 267-280Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Data-intensive analytics on large clusters is important for modern Internet services. As machines in these clusters have large memories, in-memory caching of inputs is an effective way to speed up these analytics jobs. The key challenge, however, is that these jobs run multiple tasks in parallel and a job is sped up only when inputs of all such parallel tasks are cached. Indeed, a single task whose input is not cached can slow down the entire job. To meet this "all-or-nothing" property, we have built PACMan, a caching service that coordinates access to the distributed caches. This coordination is essential to improve job completion times and cluster efficiency. To this end, we have implemented two cache replacement policies on top of PACMan's coordinated infrastructure fb-LIFE that minimizes average completion time by evicting large incomplete inputs, and LFU-F that maximizes cluster efficiency by evicting less frequently accessed inputs. Evaluations on production workloads from Facebook and Microsoft Bing show that PACMan reduces average completion time of jobs by 56% and 51% (small interactive jobs improve by 77%), and improves efficiency of the cluster by 47% and 54%, respectively.

  • 22.
    Andersen, Linda
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Andersson, Philip
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Deep Learning Approach for Diabetic Retinopathy Grading with Transfer Learning2020Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Diabetic retinopathy (DR) is a complication of diabetes and is a disease that affects the eyes. It is one of the leading causes of blindness in the Western world. As the number of people with diabetes grows globally, so does the number of people affected by diabetic retinopathy. This demand requires that better and more effective resources are developed in order to discover the disease in an early stage which is key to preventing that the disease progresses into more serious stages which ultimately could lead to blindness, and streamline further treatment of the disease. However, traditional manual screenings are not enough to meet this demand. This is where the role of computer-aided diagnosis comes in. The purpose of this report is to investigate how a convolutional neural network together with transfer learning can perform when trained for multiclass grading of diabetic retinopathy. In order to do this, a pre-built and pre-trained convolutional neural network from Keras was used and further trained and fine-tuned in Tensorflow on a 5-class DR grading dataset. Twenty training sessions were performed and accuracy, recall and specificity were evaluated in each session. The results show that testing accuracies achieved were in the range of 35% to 48.5%. The average testing recall achieved for class 0, 1, 2, 3 and 4 was 59.7%, 0.0%, 51.0%, 38.7% and 0.8%, respectively. Furthermore, the average testing specificity achieved for class 0, 1, 2, 3 and 4 was 77.8%, 100.0%, 62.4%, 80.2% and 99.7%, respectively. The average recall of 0.0% and average specificity of 100.0% for class 1 (mild DR) were obtained because the CNN model never predicted this class.

    Fulltekst (pdf)
    fulltext
  • 23.
    Andersson, Andreas
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Data- och elektroteknik.
    Spirometri med en smarttelefon: Utveckling av en app för att mäta rotationshastigheten till en spirometerprototyp för smarttelefoner2017Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Målet med detta examensarbete har varit att utveckla en app med en algoritm för att mäta rotationshastigheten hos en prototyp för en spirometerlösning till en låg kostnad för smart- telefoner. En förstudie har gjorts av smarttelefoners användbarhet för att mäta hälsotillstånd och vilka alternativa lösningar och algoritmer som finns för att mäta rörelsedetektion. I detta arbete har en app med en algoritm utvecklats för att detektera rörelser och mäta rotations- hastigheten hos spirometerprototypens turbin filmad med en smarttelefonkamera. För att metoden ska fungera är det viktigt att rotationshastigheten understiger hälften av kamerans fps (bilder per sekund). Rotationshastigheten hos turbinen måste därför begränsas och det behövs en kamera som klarar minst 120 fps för att fånga rörelserna i prototypens turbin.Arbetet har resulterat i en fungerande algoritm för att bestämma turbinens rotationshastighet. Den utvecklade algoritmen detekterar topparna i en PPG (photoplethysmogram). För att minska beräkningstiden och för att öka noggrannheten analyserar algoritmen färgintensiteten i ett begränsat område, ett s.k. ROI (Region of Interest) i varje bild. Det finns stora möjligheter att använda denna algoritm för att fortsätta utvecklingen av detta alternativa sätt att utföra spirometritester.

    Fulltekst (pdf)
    Spirometri med en smarttelefon
  • 24.
    Andersson, Måns
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Keeping an Indefinitely Growing Audit Log2022Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    An audit log enables us to discover malfeasance in a system and to understand a security breach after it has happened. An audit log is meant to preserve information about important events in a system in a non-repudiable manner. Naturally, the audit log is often a target for malicious actors trying to cover the traces of an attack. The most common type of attack would be to try to remove or modify entries which contain information about some events in the system that a malicious actor does not want anyone to know about. In this thesis, the state-of-the-art research on secure logging is presented together with a design for a new logging system. The new design has superior properties in terms of both security and functionality compared to the current EJBCA implementation. The design is based on a combination of two well-cited logging schemes presented in the literature. Our design is an audit log built on a Merkle tree structure which enables efficient integrity proofs, flexible auditing schemes, efficient queries and exporting capabilities. On top of the Merkle tree structue, an FssAgg (Forward secure sequential Aggregate) MAC (Message Authentication Code) is introduced which strengthens the resistance to truncation-attacks and provides more options for auditing schemes. A proof-of-concept implementation was created and performance was measured to show that the combination of the Merkle tree log and the FssAgg MAC does not significantly reduce the performance compared to the individual schemes, while offering better security. The logging system design and the proof-of-concept implementation presented in this project will serve as a starting point for PrimeKey when developing a new audit log for EJBCA.

    Fulltekst (pdf)
    fulltext
  • 25.
    Anggraini, Dita
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Reliability and Cost-Benefit Analysis of the Battery Energy Storage System2023Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The battery energy storage system (BESS) is crucial for the energy transition and decarbonisation of the energy sector. However, reliability assessment and capital cost challenges can hinder their widespread deployment. Reliability and cost-benefit analysis help address these challenges and assess BESS adoption's feasibility and viability, which is the aim of this project.

    A BESS contains various components such as battery packs, inverters, a DC/DC converter, a Battery Thermal Management System (BTMS), electrical protection devices, a transformer, and an Energy Management System (EMS). All these fundamental components must be considered to obtain a complete reliability prediction. Most previous studies focused on the reliability analysis of individual components, but few consider all the abovementioned components in collective reliability analysis. In this thesis, each component is mathematically modelled to estimate failure rates and then used to predict the reliability of the overall BESS system. The model accuracy is verified by comparing the computed reliability indices with the values from standards/references, showing that the proposed reliability prediction methods provide reasonable outcomes.

    Different scenarios to enhance BESS reliability through component redundancy are explored in this project. It is proved that applying component redundancy can boost the overall BESS reliability at the price of an increased capital cost. However, the enhancement in reliability and lifespan due to component redundancy can also curtail maintenance costs. A cost-benefit analysis assesses each scenario's profitability, considering manufacturers' and owners' perspectives. It helps determine the optimal balance between reliability and profitability. Redundancy applied to components with higher failure rates and lower costs improves the reliability and profitability of the BESS. The finding highlights the importance of strategic component selection for enhancing BESS reliability. Careful reliability and cost analysis should be performed simultaneously to find the most optimised BESS scenario.

    Fulltekst (pdf)
    fulltext
  • 26.
    Araujo, Jose
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Sandberg, Henrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Johansson, Karl Henrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Experimental Validation of a Localization System Based on a Heterogeneous Sensor Network2009Inngår i: ASCC: 2009 7TH ASIAN CONTROL CONFERENCE, NEW YORK: IEEE , 2009, s. 465-470Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The experimental implementation and validation of a localization system based on a heterogeneous sensor network is described. The sensor network consists of ultrasound ranging sensors and web cameras. They are used to localize a mobile robot under sensor communication constraints. Applying a recently proposed sensor fusion algorithm that explicitly takes communication delay and cost into account, it is shown that one can accurately trade off the estimation performance by using low-quality ultrasound sensors with low processing time and low communication cost versus the use of the high-quality cameras with longer processing time and higher communication cost. It is shown that a periodic schedule of the sensors is suitable in many cases. The experimental setup is discussed in detail and experimental results are presented.

    Fulltekst (pdf)
    networked_control_ascc09
  • 27.
    Araya, Cristian
    et al.
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Data- och elektroteknik.
    Singh, Manjinder
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Data- och elektroteknik.
    Web API protocol and security analysis2017Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [en]

    There is problem that every company has its own customer portal. This problem can be solved by creating a platform that gathers all customers’ portals in one place. For such platform, it is required a web API protocol that is fast, secure and has capacity for many users. Consequently, a survey of various web API protocols has been made by testing their performance and security.

    The task was to find out which web API protocol offered high security as well as high performance in terms of response time both at low and high load. This included an investigation of previous work to find out if certain protocols could be ruled out. During the work, the platform’s backend was also developed, which needed to implement chosen web API protocols that would later be tested. The performed tests measured the APIs’ connection time and their response time with and without load. The results were analyzed and showed that the protocols had both pros and cons. Finally, a protocol was chosen that was suitable for the platform because it offered high security and fast connection. In addition, the server was not affected negatively by the number of connections. Reactive REST was the web API protocol chosen for this platform.

    Fulltekst (pdf)
    Web API protocol and security analysis. CA MS
  • 28.
    Aroush, Georgek
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    An Evaluation of Testing Frameworks for Beginners inJavaScript Programming: An evaluation of testing frameworks with beginners in mind2022Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Software testing is an essential part of any development, ensuring the validity and verification of projects. As the usage and footprint of JavaScript expand, new testing frameworks in its community have made statements about being the best overall solution using minimal intervention from developers. The statements from these frameworks about being the greatest can make it difficult for JavaScript beginners to pick a framework that could affect current and future projects. By comparing different types of frameworks and establishing a guideline for others to do the same, it becomes easier for beginners and others to choose a framework according to their own required needs. The overall method uses Mario Bunge’s scientific method via stages, which helps validate the thesis as scientific. Research, empirical data from a qualitative, and objective data from a survey decide the criteria, their priority (to determine their impact and hierarchy), what frameworks to include, and how to compare them. The frameworks Jest, AVA, and Node TAP are compared based on the main criteria of simplicity, documentation, features, and their sub-criteria. Evaluating the frameworks and ranking their performance in each criterion was done through an experiment conducted on a pre-made website without any testing included. The analytic hierarchy process is the primary method used to combine the information gathered and output a result. It makes it possible to create a priority hierarchy for each criterion and subsequently makes it possible to evaluate the choices available on their fulfillment of those criteria. One of these choices will eventually be an overall more suitable fit as the optimal framework for the research question. Combining the survey and experiment data into the analytic hierarchy process revealed that Jest fit the previous criteria better than AVA and Node TAP because of Jest’s better learning curve and Stack overflow presence. AVA was just behind in those areas, while Node TAP had a poor fit for all sub-criteria compared to the other two. AVA’s almost similar evaluation to Jest shows how the open-source community and small development teams can keep up with solutions from big corporations.

    Fulltekst (pdf)
    fulltext
  • 29.
    Arrospide Echegaray, Daniel
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Data- och elektroteknik.
    Utvärdering av Självstyrandes-utvecklarramverket2016Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Inom mjukvaruteknik finns en mångfald processmetoder där var och en har ett specifikt syfte. En processmetod kan enklare beskrivas som en upprepningsbar uppsättning delsteg i syfte att utföra en uppgift och uppnå ett specifikt resultat. Majoriteten av processmetoder som har hittats i denna studie inriktar sig på den mjukvaruprodukt som är att utveckla. Det verkar finnas en brist på processmetoder som kan användas av mjukvaruutvecklare för att utveckla sin personliga utvecklingsprocess. Med personlig utvecklingsprocess menas, hur den enskilda utvecklaren väljer att strukturera det egna arbetet i syfte att uppnå ett visst re- sultat.

    Självstyrandes-utvecklarramverket (även kallad SGD-ramverket) är i skrivande stund ett nyligen utvecklat processramverk med syfte att bistå den individuella utvecklaren att ut- veckla sin personliga utvecklingsprocess. Kort beskrivet är ramverket tänkt att innehålla alla aktiviteter som kan komma att uppstå i ett utvecklingsprojekt. Problemet är att detta ramverk inte har utvärderats ännu och därför vet man inte om ramverket är relevant för att uppfylla sitt syfte. För att rama in och vägleda studien formulerades ett antal problemfråge- ställningar (1) Är ramverket fullständigt för ett mindre företag med avseende på aktivite- ter?, (2) Hur hög är kostnaden för SGD-ramverket i form av tid?

    Målet med studien är att bidra till framtida studier för ramverket genom att utföra en akt- ionsstudie där SGD-ramverket utvärderas utefter ett par specifika utvärderingskriterier.

    En induktiv kvalitativ forskningsmetod användes för att genomföra denna studie. Med in- duktiv metod menas att slutsatser dras utifrån empiriskt insamlad data och utifrån dessa ut- formas generella teorier. Mer specifikt användes metoden aktionsstudie. Data samlades in genom loggning och tidsloggning under aktionsstudiens gång. För att utvärdera ramverket användes utvärderingskriterierna (1) Fullständighet, (2) Semantisk korrekthet (3) Kostnad. En narrativ analys fördes över insamlad data för dessa kriterier med hänsyn till problemfrå- geställningarna.

    Resultat från utvärdering visade att ramverket inte ansågs fullständigt med hänsyn till dess aktiviteter. Dock näst intill fullständigt då enbart ett fåtal aktiviteter behövdes tilläggas i den utförda aktionsstudien. Totalt 3 extra aktiviteter lades till utöver de 40 som redan finns. Ca tio procent av den totala arbetstiden i aktionsstudien var i tillagda aktiviteter utanför Självstyrandes-Utvecklarramverkets ordinarie aktiviteter. Ramverkets aktiviteter ansågs även vara för granulärt formulerade i sammanhanget av ett mindre företag. Ramverket an- sågs vara högst relevant för att förbättra den individuella utvecklarens egna process. Kost- nad för införsel av Självstyrandes-Utvecklarramverket i denna studie speglar tiden det tog tills tidsanvändningen av Ramverket ansågs stabilt. Denna införelsekostnad uppskattades i form av tid och bestod av ca 3.54% av en åttatimmars arbetsdag, detta uppskattade ske un- der en införselsperiod på 24 dagar. Total tillämpningskostnad för användning av ramverket i den utförda aktionsstudien är i snitt 4,143 SEK/timme alternativt 662,88 SEK/månad. Schablonkostnaden som har använts ligger på 172,625 SEK/timme. 

    Fulltekst (pdf)
    fulltext
  • 30. Asad, H. A.
    et al.
    Wouters, Erik Henricus
    KTH.
    Bhatti, N. A.
    Mottola, L.
    Voigt, T.
    On Securing Persistent State in Intermittent Computing2020Inngår i: ENSsys 2020 - Proceedings of the 8th International Workshop on Energy Harvesting and Energy-Neutral Sensing Systems, Association for Computing Machinery, Inc , 2020, s. 8-14Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We present the experimental evaluation of different security mechanisms applied to persistent state in intermittent computing. Whenever executions become intermittent because of energy scarcity, systems employ persistent state on non-volatile memories (NVMs) to ensure forward progress of applications. Persistent state spans operating system and network stack, as well as applications. While a device is off recharging energy buffers, persistent state on NVMs may be subject to security threats such as stealing sensitive information or tampering with configuration data, which may ultimately corrupt the device state and render the system unusable. Based on modern platforms of the Cortex M*series, we experimentally investigate the impact on typical intermittent computing workloads of different means to protect persistent state, including software and hardware implementations of staple encryption algorithms and the use of ARM TrustZone protection mechanisms. Our results indicate that i) software implementations bear a significant overhead in energy and time, sometimes harming forward progress, but also retaining the advantage of modularity and easier updates; ii) hardware implementations offer much lower overhead compared to their software counterparts, but require a deeper understanding of their internals to gauge their applicability in given application scenarios; and iii) TrustZone shows almost negligible overhead, yet it requires a different memory management and is only effective as long as attackers cannot directly access the NVMs.

  • 31.
    Asbai, Ali
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Prestanda- och användbarhetsanalys av decentraliserad ledger-teknik utvecklad med antingen SQL eller Blockkedja2022Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    B-SPORT+ är ett projekt som var intresserat av att utveckla en applikation för tips och vägledning inom fysisk träning anpassad till personer med funktionsnedsättningar. B-SPORT+ identifieradebehovet av en decentraliserad ledger i applikationen. En ledger innebär en digital huvudbok som lagrar data över transaktioner utförda i en applikation. I ett tidigare arbete lyftes Blockkedja fram som en möjlig lösning för applikationen. B-SPORT+ upplevde dock att denna teknik innehöll nackdelar som hög energiförbrukning och dyr implementation. Därför skulle detta arbete undersöka,utveckla och utvärdera ett alternativ till Blockkedja med hjälp av relationsdatabaser.

    Resultatet blev två prototyper. Den första prototypen efterliknade Blockkedja-teknik genom att horisontellt fragmentera en relationsdatabas som innehöll en tabell för utförda transaktioner. Sedan användes hasning för att validera transaktioner mellan databas fragment. Det utvecklades även en prototyp med hjälp av Blockkedja-teknik, denna prototyp användes för att utvärdera den första prototypen. Utvärderingen visade att SQL-prototypens struktur minskade minnesutnyttjandet i användardatorer samt minskade den transaktioners energikonsumtionen och tid. Denna struktur tillät även moderering utav data i ledgern vilket var vitalt för den applikation B-SPORT+ ville utveckla

    Fulltekst (pdf)
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  • 32.
    Aslamy, Benjamin
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Data- och elektroteknik.
    Utveckling av ett multisensorsystem för falldetekteringsanordningar2016Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Fallolyckor bland äldre är ett stort folkhälsoproblem. Således har det utvecklats en rad olika system för fjärrövervakning av äldre för att möjliggöra en tidig detekte- ring av fallolyckor. Majoriteten av de forskningar som hittills har gjorts inom fallo- lyckor har fokuserat på att utveckla nya mer framgångsrika algoritmer just för att identifiera fall från icke-fall. Trots det visar statistiken att dödsfall och skador orsa- kade av fallolyckor ökar för varje år i samband med den ökande andel äldre perso- ner i befolkningen.

    Detta examensarbete handlar om att förbättra nuvarande falldetekteringsanord- ningar genom att täcka de brister och tillgodose de behov som finns i nuvarande tekniker. De förbättringar som har kartlagts är att kunna ge en säkrare bedömning av patientens hälsa och kunna påkalla snabbare hjälpinsats när en fallolycka har inträffat. En annan förbättring är rörelsefriheten för äldre. De ska kunna befinna sig utomhus och ha möjlighet att utföra sina dagliga aktiviteter utan att vara be- gränsade av platspositionen.

    Sammanfattningsvis kan det konstateras att ett multisensorsystem i form av en prototyp har konstruerats för att täcka de brister som har kartlagts. Utöver att pro- totypen detekterar fall och kroppsrörelser med hjälp av en accelerometersensor innehåller den även en sensor för detektering av livstecken i from av EKG. Den in- nehåller dessutom cellulära och trådlösa nätverksanslutningar i form av GPRS och Wi-Fi för att möjliggöra rörelsefriheten hos äldre. Vidare innehåller prototypen en sensor för GPS som ger information om platsposition. 

    Fulltekst (pdf)
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  • 33.
    Aurell, Erik
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    El-Ansary, Sameh
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    A physics-style approach to scalability of distributed systems2005Inngår i: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 3267, s. 266-272Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Is it possible to treat large scale distributed systems as physical systems? The importance of that question stems from the fact that the behavior of many P2P systems is very complex to analyze analytically, and simulation of scales of interest can be prohibitive. In Physics, however, one is accustomed to reasoning about large systems. The limit of very large systems may actually simplify the analysis. As a first example, we here analyze the effect of the density of populated nodes in an identifier space in a P2P system. We show that while the average path length is approximately given by a function of the number of populated nodes, there is a systematic effect which depends on the density. In other words, the dependence is both on the number of address nodes and the number of populated nodes, but only through their ratio. Interestingly, this effect is negative for finite densities, showing that an amount of randomness somewhat shortens average path length.

  • 34.
    Axbrink, William
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Factors Behind Successful Software-as-a-Service Integrations: A Case Study of a SaaS Integration at Scania2022Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    The topic of this thesis is to evaluate Software-as-a-Service (SaaS) integrations in order to create a set of guidelines to help ease the integration of SaaS systems into internal in-house developed systems. It was achieved by performing a case study on a successful SaaS integration to locate relevant success factors to incorporate into upcoming SaaS integrations. The primary findings included a focus on the usage of standard solutions, experienced cooperation from the SaaS contractor and tactical usage of technical debt that extends the whole life cycle. While there are many success factors that aided to create a successful integration, there are still drawbacks to certain techniques that will have to be decided by the specific integrations requirements if the trade-off is worth it. There were other success factors that weighted in but was not crucial to the success, and certain factors that should be treated with caution due to the harmful effect it might have upon the project. Using the factors found in the case study, a set of guidelines with a focus on the processes and work methodology were created to ease future SaaS integrations for organizations and institutions.

    Fulltekst (pdf)
    fulltext
  • 35.
    Axtelius, Mathias
    et al.
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Data- och elektroteknik.
    Alsawadi, Rami
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Data- och elektroteknik.
    An improved selection algorithm for access points in wireless local area networks: An improved selection algorithm for wireless iopsys devices2016Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [en]

    Wireless devices search for access points when they want to connect to a network. A devicechooses an access point based on the received signal strength between the device and theaccess point. That method is good for staying connected in a local area network but it doesnot always offer the best performance, which can result in a slower connection. This is thestandard method of connection for wireless clients, which will be referred to as the standardprotocol. Larger networks commonly have a lot of access points in an area, which increasesthe coverage area and makes loss of signal a rare occurrence. Overlapping coverage zonesare also common, offering multiple choices for a client. The company Inteno wanted an alternativeconnection method for their gateways. The new method that was developed wouldforce the client to connect to an access point depending on the bitrate to the master, as wellas the received signal strength. These factors are affected by many different parameters.These parameters were noise, signal strength, link-rate, bandwidth usage and connectiontype. A new metric had to be introduced to make the decision process easier by unifying theavailable parameters. The new metric that was introduced is called score. A score system wascreated based on these metrics. The best suited access point would be the one with the highestscore. The developed protocol chose the gateway with the highest bitrate available, while thestandard protocol would invariably pick the closest gateway regardless. The developed protocolcould have been integrated to the standard protocol to gain the benefits of both. Thiscould not be accomplished since the information was not easily accessible on Inteno’s gatewaysand had to be neglected in this thesis.

    Fulltekst (pdf)
    fulltext
  • 36.
    Baccelli, Guido
    et al.
    Politecn Torino, DET, Turin, Italy..
    Stathis, Dimitrios
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Hemani, Ahmed
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elektronik och inbyggda system, Elektronik och inbyggda system.
    Martina, Maurizio
    Politecn Torino, DET, Turin, Italy..
    NACU: A Non-Linear Arithmetic Unit for Neural Networks2020Inngår i: PROCEEDINGS OF THE 2020 57TH ACM/EDAC/IEEE DESIGN AUTOMATION CONFERENCE (DAC), IEEE , 2020Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Reconfigurable architectures targeting neural networks are an attractive option. They allow multiple neural networks of different types to be hosted on the same hardware, in parallel or sequence. Reconfig-urability also grants the ability to morph into different micro-architectures to meet varying power-performance constraints. In this context, the need for a reconfigurable non-linear computational unit has not been widely researched. In this work, we present a formal and comprehensive method to select the optimal fixed-point representation to achieve the highest accuracy against the floating-point implementation benchmark. We also present a novel design of an optimised reconfigurable arithmetic unit for calculating non-linear functions. The unit can be dynamically configured to calculate the sigmoid, hyperbolic tangent, and exponential function using the same underlying hardware. We compare our work with the state-of-the-art and show that our unit can calculate all three functions without loss of accuracy.

  • 37.
    Baharloo, Mohammad
    et al.
    University of Tehran, Tehran, Iran.
    Khonsari, Ahmen
    University of Tehran, Tehran, Iran.
    Dolati, Mahdi
    University of Tehran, Tehran, Iran.
    Shiri, Pouya
    University of Victoria, BC, Canada.
    Ebrahimi, Masoumeh
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elektronik och inbyggda system, Elektronik och inbyggda system.
    Rahmati, Dara
    University of Tehran, Tehran, Iran.
    Traffic-aware performance optimization in Real-time wireless network on chip2020Inngår i: Nano Communication Networks, ISSN 1878-7789, E-ISSN 1878-7797, Vol. 26, artikkel-id 100321Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Network on Chip (NoC) is a prevailing communication platform for multi-core embedded systems. Wireless network on chip (WNoC) employs wired and wireless technologies simultaneously to improve the performance and power-efficiency of traditional NoCs. In this paper, we propose a deterministic and scalable arbitration mechanism for the medium access control in the wireless plane and present its analytical worst-case delay model in a certain use-case scenario that considers both Real-time (RT) and Non Real-time (NRT) flows with different packet sizes. Furthermore, we design an optimization model to jointly consider the worst-case and the average-case performance parameters of the system. The Optimization technique determines how NRT flows are allowed to use the wireless plane in a way that all RT flows meet their deadlines, and the average case delay of the WNoC is minimized. Results show that our proposed approach decreases the average latency of network flows up to 17.9%, and 11.5% in 5 × 5, and 6 × 6 mesh sizes, respectively.

    Fulltekst (pdf)
    fulltext
  • 38.
    Baheux, Ivan
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Context-aware security testing of Android applications: Detecting exploitable vulnerabilities through Android model-based security testing2023Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This master’s thesis explores ways to uncover and exploit vulnerabilities in Android applications by introducing a novel approach to security testing. The research question focuses on discovering an effective method for detecting vulnerabilities related to the context of an application. The study begins by reviewing recent papers on Android security flaws affecting application in order to guide our tool creation. Thus, we are able to introduce three Domain Specific Languages (DSLs) for Model-Based Security Testing (MBST): Context Definition Language (CDL), Context-Driven Modelling Language (CDML), and Vulnerability Pattern (VPat). These languages provide a fresh perspective on evaluating the security of Android apps by accounting for the dynamic context that is present on smartphones and can greatly impact user security. The result of this work is the development of VPatChecker[1], a tool that detects vulnerabilities and creates abstract exploits by integrating an application model, a context model, and a set of vulnerability patterns. This set of vulnerability patterns can be defined to represent a wide array of vulnerabilities, allowing the tool to be indefinitely updated with each new CVE. The tool was evaluated on the GHERA benchmark, showing that at least 38% (out of a total of 60) of the vulnerabilities in the benchmark can be modelled and detected. The research underscores the importance of considering context in Android security testing and presents a viable and extendable solution for identifying vulnerabilities through MBST and DSLs.

    Fulltekst (pdf)
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  • 39.
    Balachandran, Sarugan
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Perez Legrand, Diego
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Evaluating machine learning models for time series forecasting in smart buildings2023Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [en]

    Temperature regulation in buildings can be tricky and expensive. A common problem when heating buildings is that an unnecessary amount of energy is supplied. This waste of energy is often caused by a faulty regulation system. This thesis presents a machine learning ap- proach, using time series data, to predict the energy supply needed to keep the inside tem- perature at around 21 degrees Celsius. The machine learning models LSTM, Ensemble LSTM, AT-LSTM, ARIMA, and XGBoost were used for this project. The validation showed that the ensemble LSTM model gave the most accurate predictions with the Mean Absolute Error of 22486.79 (Wh) and Symmetric Mean Absolute Percentage Error of 5.41 % and was the model used for comparison with the current system. From the performance of the different models, the conclusion is that machine learning can be a useful tool to pre- dict the energy supply. But on the other hand, there exist other complex factors that need to be given more attention to, to evaluate the model in a better way.

    Fulltekst (pdf)
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  • 40. Ben Dhaou, I.
    et al.
    Tenhunen, Hannu
    KTH, Tidigare Institutioner (före 2005), Elektroniksystemkonstruktion.
    Efficient library characterization for high-level power estimation2004Inngår i: IEEE Transactions on Very Large Scale Integration (vlsi) Systems, ISSN 1063-8210, E-ISSN 1557-9999, Vol. 12, nr 6, s. 657-661Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper describes LP-DSM, which is an algorithm used for efficient library characterization in high-level power estimation. LP-DSM characterizes the power consumption of building blocks using the entropy of primary inputs and primary outputs. The experimental results showed that over a wide range of benchmark circuits implemented using full custom design in 0.35-mum 3.3 V CMOS process the statistical performance (mean and maximum error) of LP-DSM is comparable or sometimes better than most of the published algorithms. Moreover, it was found that LP-DSM has the lowest prediction sum of squares, which makes it an efficient tool for power prediction. Furthermore, the complexity of the LP-DSM is linear in relation to the number of primary inputs (O(NI)), whereas state of the art published library characterization algorithms have a complexity of O(NI2).

  • 41.
    Berg, Johan
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Mebrahtu Redi, Daniel
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Benchmarking the request throughput of conventional API calls and gRPC: A Comparative Study of REST and gRPC2023Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    As the demand for better and faster applications increase every year, so does the demand for new communication systems between computers. Today, a common method for computers and software systems to exchange information is the use of REST APIs, but there are cases where more efficient solutions are needed. In such cases, RPC can provide a solution. There are many RPC libraries to choose from, but gRPC is the most widely used today.

    gRPC is said to offer faster and more efficient communication than conventional web-based API calls. The problem investigated in this thesis is that there are few available resources demonstrating how this performance difference translates into request throughput on a server.

    The purpose of the study is to benchmark the difference in request throughput for conventional API calls (REST) and gRPC. This was done with the goal of providing a basis for making better decisions regarding the choice of communication infrastructure between applications. A qualitative research method with support of quantitative data was used to evaluate the results.

    REST and gRPC servers were implemented in three programming languages. A benchmarking client was implemented in order to benchmark the servers and measure request throughput. The benchmarks were conducted on a local network between two hosts.

    The results indicate that gRPC performs better than REST for larger message payloads in terms of request throughput. REST initially outperforms gRPC for small payloads but falls behind as the payload size increases. The result can be beneficial for software developers and other stakeholders who strive to make informed decisions regarding communication infrastructure when developing and maintaining applications at scale.

    Fulltekst (pdf)
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  • 42.
    Berg, Linus
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Ståhl, Felix
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Mainframes and media streaming solutions: How to make mainframes great again2020Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Mainframes has been used for well over 50 years and are built for processing demanding workloads fast, with the latest models using IBM’s z/Architecture processors. In the time of writing, the mainframes are a central unit of the world’s largest corporations in banking, finance and health care. Performing, for example, heavy loads of transaction processing. When IBM bought RedHat and acquired the container orchestration platform OpenShift, the IBM lab in Poughkeepsie figured that a new opportunity for the mainframe might have opened. A media streaming server built with OpenShift, running on a mainframe. This is interesting because a media streaming solution built with OpenShift might perform better on a mainframe than on a traditional server. The initial question they proposed was ’Is it worth running streaming solutions on OpenShift on a Mainframe?’. First, the solution has to be built and tested on a mainframe to confirm that such a solution actually works. Later, IBM will perform a benchmark to see if the solution is viable to sell. The authors method includes finding the best suitable streaming software according to some criterias that has to be met. Nginx was the winner, being the only tested software that was open-source, scalable, runnable in a container and supported adaptive streaming. With the software selected, configuration with Nginx, Docker and OpenShift resulted in a fully functional proof-of-concept. Unfortunately, due to the Covid-19 pandemic, the authors never got access to a mainframe, as promised, to test the solution, however, OpenShift is platform agnostic and should, theoretically, run on a mainframe. The authors built a base solution that can easily be expanded with functionality, the functionality left to be built by IBM engineers is included in the future works section, it includes for example, live streaming, and mainframe benchmarking.

    Fulltekst (pdf)
    fulltext
  • 43.
    Bhuddi, Amita
    et al.
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Data- och elektroteknik.
    Somos, Oliver
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Data- och elektroteknik.
    Återställningsverktyg för fordon baserat på applikationsintegration2016Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Mjukvarutestningsgruppen på Scania använder en manuell och tidskrävande process för att återställa testfordon efter sina utförda arbeten. I den återställningsprocessen ingår ett antal olika applikationer för att kunna säkerställa att fordonet är i samma skick som det var innan testerna. För att förbättra arbetsflödet med minskad arbetsbelastning och att försäkra en säkrare process var de intresserade av att utveckla ett återställningsverktyg som kan göra detta uppdrag. Önskemålet var att skapa detta genom att återanvända så mycket av de redan tillgängliga komponenterna som möjligt. Då det fanns flera komponenter som uppfyllde funktionskraven för de flesta funktionaliteten krävdes det en undersökning för att avgöra vilka ska användas. Denna gjordes med hjälp av integrationsmodellen Enterprise Application Integration, där målet är att utveckla en slutprodukt av applikationerna som används inom en organisation för att förenkla bland annat underhåll, datahantering och utbildning av medarbetarna. En prototyp har tagits fram som implementerar tre existerande moduler på olika nivåer och som enligt målet med EAI själv är en enkel mjukvara som möjliggör att komponenterna tillsammans utför arbetet.

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  • 44.
    Bilardi, Gianfranco
    et al.
    Univ Padua, Dept Informat Engn, I-35131 Padua, Italy..
    Scquizzato, Michele
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Datavetenskap, Teoretisk datalogi, TCS. Univ Padua, Padua, Italy.
    Silvestri, Francesco
    Univ Padua, Dept Informat Engn, I-35131 Padua, Italy..
    A Lower Bound Technique for Communication in BSP2018Inngår i: ACM TRANSACTIONS ON PARALLEL COMPUTING, ISSN 2329-4949, Vol. 4, nr 3, artikkel-id UNSP 14Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Communication is a major factor determining the performance of algorithms on current computing systems; it is therefore valuable to provide tight lower bounds on the communication complexity of computations. This article presents a lower bound technique for the communication complexity in the bulk-synchronous parallel (BSP) model of a given class of DAG computations. The derived bound is expressed in terms of the switching potential of a DAG, that is, the number of permutations that the DAG can realize when viewed as a switching network. The proposed technique yields tight lower bounds for the fast Fourier transform (FFT), and for any sorting and permutation network. A stronger bound is also derived for the periodic balanced sorting network, by applying this technique to suitable subnetworks. Finally, we demonstrate that the switching potential captures communication requirements even in computational models different from BSP, such as the I/O model and the LPRAM.

  • 45.
    Blanco Paananen, Adrian
    et al.
    KTH, Skolan för datavetenskap och kommunikation (CSC).
    Storby, Johan
    KTH, Skolan för datavetenskap och kommunikation (CSC).
    Observing coevolution in simulated bacteria: Using asexual reproduction and simple direct mapped functions for decision-making2014Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    In this report we have presented the results of a program which performs simula- tions of artificial bacteria with the ability to evolve different characteristics and behaviours through genetic algorithms. Over time unfit bacteria will die out, and the more fit bacteria will produce offspring with slightly mutated variants of it’s genetic code resembling the evolutionary process. The simulation does not follow the traditional macro-scale hand-picked sexual reproduction often used in genetic algorithms to produce optimal results, but it instead uses individ- ual asexual reproduction which more closely resembles how bacteria reproduce in nature. Furthermore we do not use traditional neural networks for decision making, but simple functions which directly map the bacterias inputs to their decisions.

    The purpose of this study was to observe whether bacteria with different initial starting populations would coevolve, and specialize into heterogeneous populations. Furthermore we have tried to analyze how the populations inter- act with each other and how changing the different parameters of the simulation would affect the populations. We have performed three separate experiments that differ in their initial conditions, one with pre-created and heterogeneous herbivores and carnivores, one with homogeneous omnivores, and one with bac- teria whose genetic values have been decided at random. The result of our experiments was that we observed coevolution in the bacteria, and that they would despite very different initial starting conditions always grow towards sta- ble heterogeneous populations with very few exceptions. 

    Fulltekst (pdf)
    fulltext
  • 46.
    Blom, Marcus
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Hammar, Kim
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Integrating Monitoring Systems - Pre-Study2016Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [en]

    Failures in networks that reside in business environments cause harm to organizations depending on them. Every minute of inoperativety is hurtful and as a network adminstrator you want to minimize the rates of failures as well as the time of inoperation. Therefore, a fruitful network monitoring system is of great interest for such organizations. This bachelor’s thesis is the outcome of a pre-study performed on behalf of MIC Nordic and sought to advice them in the implementation of a new monitoring system.

    The aim of this study was to investigate how a Network Operation Center (NOC) can be implemented in an existing monitoring environment, to integrate current monitoring systems to a central point for monitoring. This study takes an holitstic approach to network management and the research can be divided into two main categories: Communication between network components and Presentation of information. Our process involves an analysis of the environment of MIC Nordic and an in depth inquiry on the current state of network monitoring and interface design. The study then culminates in the implementation of a prototype. The prototype serves in first hand as a research tool to collect experience and empirical evidence to increase the crediblity of our conclusions. It is also an attempt of demonstrating the complete process behind developing a NOC, that we believe can fill a gap among the previous research in the field.

    From our results you can expect a prototype with functionality for monitoring network components and a graphical user interface (GUI) for displaying information. The results are designed towards solving the specific network management problem that was given and the environment that it concerns. This pre-study suggests that the best solution for implementing a NOC in the given environment is to use SNMP for communication. From an investigation on how to present network management information in a effective way we propose to follow a user-centered approach and to utilize human perception theory in the design process. The authors recommend further research that maintain the holistic approach but applies more quantitative methods to broaden the scope.

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  • 47. Bonnichsen, L.
    et al.
    Podobas, Artur
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Programvaruteknik och Datorsystem, SCS.
    Using transactional memory to avoid blocking in OpenMP synchronization directives: Don’t wait, speculate!2015Inngår i: 11th International Workshop on OpenMP, IWOMP 2015, Springer, 2015, s. 149-161Konferansepaper (Fagfellevurdert)
    Abstract [en]

    OpenMP applications with abundant parallelism are often characterized by their high-performance. Unfortunately, OpenMP applications with a lot of synchronization or serialization-points perform poorly because of blocking, i.e. the threads have to wait for each other. In this paper, we present methods based on hardware transactional memory (HTM) for executing OpenMP barrier, critical, and taskwait directives without blocking. Although HTM is still relatively new in the Intel and IBM architectures, we experimentally show a 73% performance improvement over traditional locking approaches, and 23% better than other HTM approaches on critical sections. Speculation over barriers can decrease execution time by up-to 41 %. We expect that future systems with HTM support and more cores will have a greater benefit from our approach as they are more likely to block.

  • 48.
    Brask, Anton
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Berendt, Filip
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Analyzing the scalability of R*-tree regarding the neuron touch detection task2020Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    A common task within research of neuronal morphology is neuron touch detection, that is finding the points in space where two neurites approach each other to form a synapse. In order to make efficient use of cache memory, it is important to store points that are close in space close in memory. One data structure that aims to tackle this complication is the R*-tree. In this thesis, a spatial query for touch detection was implemented and the scalability of the R*-tree was estimated on realistic neuron densities and extrapolated to explore execution times on larger volumes. It was found that touch detection on this data structure scaled much like the optimal algorithm in 3D-space and more specifically that the computing power needed to analyze a meaningful portion of the human cortex is not readily available.

    Fulltekst (pdf)
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  • 49.
    Braun, Stefan
    KTH, Skolan för elektro- och systemteknik (EES), Mikrosystemteknik.
    Wafer-level heterogeneous integration of MEMS actuators2010Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis presents methods for the wafer-level integration of shape memory alloy (SMA) and electrostatic actuators to functionalize MEMS devices. The integration methods are based on heterogeneous integration, which is the integration of different materials and technologies. Background information about the actuators and the integration method is provided.

    SMA microactuators offer the highest work density of all MEMS actuators, however, they are not yet a standard MEMS material, partially due to the lack of proper wafer-level integration methods. This thesis presents methods for the wafer-level heterogeneous integration of bulk SMA sheets and wires with silicon microstructures. First concepts and experiments are presented for integrating SMA actuators with knife gate microvalves, which are introduced in this thesis. These microvalves feature a gate moving out-of-plane to regulate a gas flow and first measurements indicate outstanding pneumatic performance in relation to the consumed silicon footprint area. This part of the work also includes a novel technique for the footprint and thickness independent selective release of Au-Si eutectically bonded microstructures based on localized electrochemical etching.

    Electrostatic actuators are presented to functionalize MEMS crossbar switches, which are intended for the automated reconfiguration of copper-wire telecommunication networks and must allow to interconnect a number of input lines to a number of output lines in any combination desired. Following the concepts of heterogeneous integration, the device is divided into two parts which are fabricated separately and then assembled. One part contains an array of double-pole single-throw S-shaped actuator MEMS switches. The other part contains a signal line routing network which is interconnected by the switches after assembly of the two parts. The assembly is based on patterned adhesive wafer bonding and results in wafer-level encapsulation of the switch array. During operation, the switches in these arrays must be individually addressable. Instead of controlling each element with individual control lines, this thesis investigates a row/column addressing scheme to individually pull in or pull out single electrostatic actuators in the array with maximum operational reliability, determined by the statistical parameters of the pull-in and pull-out characteristics of the actuators.

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  • 50.
    Brejcha, Kevin
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Data- och elektroteknik.
    Prestandaanalys av HTTP/22015Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Swedbank är en av Sveriges största företag inom finanssektorn med drygt fyra miljoner privatkunder och försöker ständigt utveckla sina tjänster så att de är lättåtkomliga och lättanvända för kunderna. För att tillfredsställa sina kunders behov av en snabb och lättåtkomlig bank så vill Swedbank minska på laddningstiderna till sina finanstjänster, särskilt de mobila tjänsterna då det är där uppkopplingarna är som långsammast. Uppdraget var att göra en prestandaanalys av HTTP/2 som är den senaste versionen av HTTP-protokollet. Efter att ha genomfört arbetet ska Swedbank veta vad dem kan anpassa för att göra sina tjänster så optimala som möjligt för framtiden.Resultatet visade att med hjälp av HTTP/2’s nya funktioner, bland annat det binära ramlagret, uppnåddes en prestandaökning på 44% av totala laddningstiden på Swedbank’s hemsida. Testerna genomfördes i en lokal labbmiljö där de olika HTTP versionerna installerades och mätvärden dokumenterades. Detta ansågs som ett bra resultat utan att ha genomfört någon fördjupande konfiguration.

    Fulltekst (pdf)
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