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  • 201.
    Engberg, Anna
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Kommunikation mellan olika märken av växelriktare och tredjepartsprogram2016Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Det finns en mängd olika tillverkare av solcellssystem idag och dessa säljer sina egna programvaror och övervakningsmöjligheter. När en produkt är ny och i sin linda kan det vara oklart vilken teknik som skall bli ledande och därför väljer ett företag att satsa brett och sprida sina risker. Samtidigt som det är en fördel blir påföljden ofta vissa kompabilitetsproblem. Genom att kartlägga Umeå Energis solcellsanläggningar, sammanställa olika växelriktares protokoll och kommunikationsvägar kan en gemensam standard urskiljas. Målet med denna rapport är att föreslå en lösning på loggning och datainsamling genom att hitta ett gemensamt protokoll eller plattform. Det kommunikationsprotokoll alla växelriktare i denna rapport kan använda sig av är Modbus RTU. Men för att bygga ett framtidssäkert kommunikationsnät rekommenderar författaren Modbus TCP.

  • 202.
    Engberg, Emelie
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Landerup, Marina
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Riskidentifiering inom elektronisk kommunikation i Hallands län: Vilka hot föreligger den elektroniska kommunikationen och vilka risker innebär det?2014Independent thesis Basic level (university diploma), 5 poäng / 7,5 hpOppgave
    Abstract [sv]

    Den elektroniska kommunikationen är idag en stor och viktig del i vardagen, därför beslutade sig Länsstyrelsen i Hallands län för att starta ett projekt där de i ett samarbete med Högskolan i Halmstad skulle utföra en fullständig risk- och sårbarhetsanalys inom sektorn elektronisk kommunikation, tillsammans med kommunerna och regionen i Hallands län. Som en första del i en risk- och sårbarhetsanalys, måste en riskidentifiering göras och det är det som är syftet med rapporten. Resultatdelen i rapporten bygger på en sammanställning av svar från intervjuer med anställda inom kommunerna och Region Halland.

    Riskerna som föranletts av de identifierade hoten är relativt många och är av olika form och allvarlighetsgrad. Den vanligaste risken är att system periodvis blir långsamma, ett exempel på detta är att lönesystemet blir långsammare i slutet av månaden då det blir överbelastat för att alla löner ska betalas ut. Genom redundans i systemen reduceras risker som störningar, långsamma system och otillgängliga program och funktioner.

    Mycket ansvar kring säkerheten läggs på IT-avdelningen som många gånger känner att det både saknas ekonomiska medel men också tidsbrist för att upprätthålla en önskvärd säkerhet.

    Slutligen vill vi påstå att hotbildsanalyser och riskidentifieringar är viktiga att utföra för att kunna upprätthålla säkerhet och skydda verksamheten på rätt sätt. 

  • 203.
    Engquist, Martin
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Bethdavid, Simon
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Communications solution for refugee settlement: Investigation of nRF24L01+ modules for use in a communications network2018Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    The main purpose of this thesis is to test a communications solution for the second to largest refugee settlement in the world, Bidi Bidi. A solution where it is possible to inform the refugees with necessary information, for example that the water at a specific location is currently contaminated or that food is provided at another location. The idea is to use nRF24L01+ modules which operate in the 2.4 GHz frequency band and send information through various ways. This includes turning LEDs' on and off, sending text Strings and streaming audio. The results showed that the modules are too unreliable for a refugee settlement. They also showed that it is not possible to send other types' of data while streaming audio, but there could be workarounds. It is clear that more knowledge and further investigations are needed.

  • 204.
    Engström, Pontus
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Modernizing forms at KTH: Using Digital Signatures2016Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Today both government agencies and companies struggle to keep up with the pace of the continuous change of technology. With all new technology there are benefits, but new problems might also occur. Implementing new technology for certain tasks may increase both efficiency and security, resulting in a more sustainable work environment. One technology that is increasingly adopted is digital signatures. Instead of using classical handwritten signatures on documents, a digital signature can be more time efficient and have higher security.

    In order to implement a digital signature technology some security aspects must be addressed and certain properties ensured. In the document signature process, each time an individual verifies a signature attached onto a document a log entry is created. This log contains information about who verified which document, does it have multiple parts that have been signed, does it need multiple signatures in order to be valid, and at what time and date was the document signed. Logs help to ensure the validity of the document and thereby increase the security provided by the digital signatures.

    At KTH, a student must sign an application form with a regular ink-written signature to start a thesis project. This process can in most cases delay the start up to two weeks. This study aims to implement digital signatures for one specific form, an application form for a thesis project. The hypothesis at the start of the project was that the use of digital signature would decrease the time of waiting significantly. Personnel at KTH using digital signature would facilitate their work efficiency, due to less printing and archiving of papers as well fewer meetings.

    This study will provide the reader with the necessary fundamental knowledge of cryptography and how digital signatures use this underlying technology. The methodology used in this study was to identify and modify certain software settings, as well collect data from students and personnel at KTH. The collected data was based on time measurements of digital signature processes from students and a faculty member. The results show digital signatures are faster than the current signing process with traditional ink-written signatures. Additionally, the use of digital signatures is expected to reduce the need for printing, transport, and sorting of paper documents. The resulting reduction in use of physical paper should provide environmental benefits.

  • 205.
    Enlund, Simon
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Jourkovski, Alexander
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Implementing a telemedicine system for remote medical consultation2016Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Telemedicine is the combination of information technology (IT) and health care and is an area that has seen increase during the last few decades due to breakthroughs in IT. Today there are still parts of the health care system that can be counterproductive with regards to the time and commitment necessary. One such part is medical consultations for private individuals where many of the simpler ones are still carried out in-person.

    Presented in this thesis is the implementation of a prototype telemedicine system that could be used as a substitute for in-person doctor-patient consultation. Necessary 3rd party components and their implementations into one system are described on a general use level. The result is a web application that supports login and payment via trusted sources, booking of meetings and carrying them out with video and audio.

    The prototype is a continuation of a telemedicine web application idea that was put on ice by a company that already provides solutions for health controls and blood analysis.

  • 206.
    Enni, Federico
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    The Leaf project: a first application2011Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Today large publishers are developing platforms via which their content, such as magazines, books, and newspapers, are distributed based upon the well established pattern of 'pay-per-content', via a multitude of mobile applications. Despite of the recent flourishing market of subscription possibilities, users currently have to buy single items of content at an average expenditure that is approximately equal to the cost of the printed media, because publishers are still investing in printing hardcover versions of their publications.

    Furthermore currently digital documents are mainly "scanned" versions of the printed ones, an unattractive format which does not exploit the potential of digital publishing. This format is rendered by the device in a way that does not permit the user to take real advantages of a digital environment, making the e-reading experience something that has no real added values, compared to regular printed publications.

    In order to provide to people an improved experience in terms of both accessing and enjoying their favorite material, the Leaf project aims to create a platform in which both publishers and readers can take advantage of an innovative business model and advanced technological solutions.

    As part of the Leaf project, the main objective in this subproject is the realization of a client that can access a set of online contents and offer these to the reader, by streaming content rather than requiring that the complete object should be downloaded in order to be rendered by the device. The access to the material should follow modern security standards, including data encryption, in order to prevent unauthorized use of the content. Furthermore, the client should present the content in an innovative way and allow the development of a mobile platform that could be supported based upon advertising, with an approach based on using information about the user (i.e. favorite places or profile details)as well as content-based advertising.

    In addition to the client application, the development of this subproject includes the development of a series of server-side utilities for the uploading and elaboration of publications on the server infrastructure.

    The document first reviews e-reading systems, focusing on the ePub file definition and e-reading solutions currently in use. The report then describes the Android OS development environment. The document then explains the implementation for both client and server side applications, giving a detailed overview of the chosen strategies and of the applications' structure. Finally the report concludes with a list of the achieved goals, a discussion on the project's limitations and then an exploration on what is the future for this client application.

  • 207.
    Ericsson, Andreas
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Ericsson, Jonas
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Fjärrstyrning av värmepump2013Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Att fjärrstyra sin värmepump gör det möjligt att styra inomhusklimatet även då man inte är hemma. Detta passar mycket bra i exempelvis fritidshus då man enkelt kan höja temperaturen innan man skall dit och därmed kan njuta av ett behagligt inomhusklimat direkt.

    Med dagens fjärrstyrning av Daikins värmepumpar finns två problem. Systemet använder GSM-nätet och användaren måste kunna de olika SMS-koderna utantill. Fjärrstyrning används oftast i fritidshus på landsbygden och 3G-nätet har idag bättre täckning än GSM-nätet på många av dessa platser.

    Målet med examensarbetet är att ta fram ett system som åtgärdar dessa problem.

    Vi börjar med att ta fram en funktionsmodell att utgå från. Går vidare med val av hårdvara för modulen, och därefter vidare till mjukvaruutveckling.

    Resultatet av detta examensarbete är ett system för fjärrstyrning av Daikins värmepumpar som använder 3G-nätet och enkelt kan styras via en androidapplikation.

  • 208.
    Ericsson, Fredrik
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Agent based mobile Internet services2002Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis investigates how to develop mobile SMS services using Personal Internet Agents. A platform for Personal Internet Agents is implemented to serve as a framework in which mobile services can easily be created, executed, and administered. The services are based on extracting information and events from various sources on the Internet, then communicating these to the mobile end user.

    To evaluate the platform several investigations are carried out regarding scalability, integration possibilities, and performance. To illustrate the functionality of the platform a full-blown mobile service is developed that illustrates the gain of the Personal Internet Agents in combination with the mobile Internet. The service, named Spymail, fetches e-mail from Microsoft’s Hotmail and forwards these to the user via SMS.

    Developing services based on agents rises several issues. Since web sites on the Internet sometimes change, go down, etc, agents have to be informed about this to be able to adapt to the situation. Another issue is if it is possible to create a large multi-user agent service or if the bandwidth or computational speed will be a constraint.

  • 209.
    Ericsson, Marcus
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska fakulteten.
    Transmission, Storage, and Visualization of Data with ANT+2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Ultra low-powers wireless technology sensors uses when devices is used to consumeslow power. ANT+ sensors can run for years on a single coin battery. In thethesis the ANT+ sensor data is used in an application that can store and visualizethe data.

  • 210.
    Ericsson, Simon
    et al.
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för datavetenskap, fysik och matematik, DFM.
    Dalesjö, Jonas
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för datavetenskap, fysik och matematik, DFM.
    Viktiga faktorer för användandet av mobila betalningar2013Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Sammanfattning

    Bara de senaste åren har det lanserats ett flertal nya betalningstjänster för mobiltelefoner, men ingen har fått det genomslag som förväntades. Varför tar inte konsumenterna till sig dessa lösningar?  Denna studie lyfter fram faktorer som har direkt påverkan för användandet av dessa nya tekniker. Faktorerna har identifierats med hjälp av vår litteraturstudie på utökade TAM-modeller från tidigare forskning som försöker förklara acceptans och adoptering av mobila betalningar. Faktorerna som framkom genom litteraturstudien är grunden för vår kvantitativa undersökning, som använder enkäter för insamlandet av data. Dessa faktorer utvärderas tillsammans med två egenhändigt framtagna faktorer för att identifiera vilka faktorer som är viktigast för anammandet av mobila betalningstjänster. Målsättningen var att nå ut till en så stor målgrupp som möjligt för att resultatet skulle bli generaliserbart. Resultatet blev inte helt som vi hade förväntat oss. Faktorer som användarvänlighet, användbarhet och kompabilitet var av ytterst stor vikt, medan säkerhet som tidigare forskning lyfte fram som den viktigaste inte fick alls samma betydelse i vår undersökning.

  • 211.
    Erikson, Gustaf
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Application of inertial sensing to handheld terminals2001Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    We consider the potential for using inertial sensing in handheld terminals.As an example, the implementation of an inertial sensing system in twodimensions for the research terminal Tifón at Ericsson Radio is discussed.The implementation includes hardware design, microcode software for aneight-bit micro-controller, and software for communication with the operat-ing system of the terminal.

  • 212.
    Eriksson, Emil
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Signaler och System.
    Refinement of an emulator for the physical layer of the wireless communication of sensor networks2014Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Wireless sensor networks have applications in many different fields and environments, each with their own set of challenges to be overcome. If we can measure and compensate for the properties of the wireless environment at an early stage of the deployment, we will be able to have the sensor network operational in a smaller time frame.

    This report describes the development of an emulator for wireless sensor network of up to eight 802.15.4 complaint sensor nodes. The FPGA-based emulator has been enhanced with several new features to remove some shortcomings of the existing emulator. The emulator now provides the ability to import previously recorded data representing time varying gains of wireless links, the ability to store the signal data generated by the sensor node for later review, as well as a more intuitive user interface to make the emulator more useful as a research tool. A latency issue that previously prevented the use of any communications protocol depending of transmission acknowledgments has been studied and a solution to the issue is presented. A way of introducing external interference to the emulated system has also been investigated and provides a straightforward way of introducing interference to the system without modifying the existing hardware and software.

    Most added features have been designed to be easily modified or expanded upon.

  • 213.
    Eriksson, Gustav
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Towards Long-Range Backscatter Communication with Tunnel Diode Reflection Amplifiers2018Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Backscatter communication enables wireless communication at a power consumption orders of magnitude lower than conventional wireless communication. Instead of generating new RF-signals backscatter communication leverages ambient signals, such as WiFi-, Bluetooth- or TV-signals, and reflects them by changing the impedance of the antenna. Backscatter communication is known as a short-range communication technique achieving ranges in the order of meters. To improve the communication range, we explore the use of a tunnel diode as an amplifier of the backscattered RF-signal. We developed the amplifier on a PCB-board together with a matching network tuned to give maximum gain at 868 MHz. Our work demonstrates that the 1N3712 tunnel diode can achieve gains up to 35 dB compared to a tag without amplification while having a peak power consumption of 48 μW. With this amplifier the communication distance can be increased by up to two orders of magnitude.

  • 214.
    Eriksson, Hannes
    et al.
    Högskolan i Halmstad.
    Brange Sollie, Ivan
    Högskolan i Halmstad.
    Wireless IO: A wireless accessory for integration of an Axis Communications camera in a sensor network.2017Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    When installing new network security cameras in buildings, the cameras are often connected to sensors via signal wires. Since most building already have internet and electricity drawn throughout the structure, the procedure of routing a new signal wire can be costly and time demanding. By replacing this wire with a wireless link, the cost and time it takes for the customer to install a camera could be reduced.

    The objective for this thesis is to investigate different wireless technologies used in short range, low power wireless communication networks such as PANs and LANs. Focusing on technologies used in the surveillance segment a decision will be made on which wireless technology that would suit as a link between a sensor and a camera for transmitting trigger signals. The technology will then be implemented in a proof-of-concept accessory, which can give an Axis Communications camera wireless functionality through it’s IO port.

  • 215.
    Eriksson, Henrik
    KTH, Tidigare Institutioner, Teleinformatik. KTH, Skolan för informations- och kommunikationsteknik (ICT).
    The Personal Assistant Framework: Enabling Augmented Reality in OrdinaryWeb Browsers1997Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This paper presents a secure framework for building personal assistants in a web browser environment. These assistants are personal computer programs, working on the behalf of their user. Around a minimal core of system resources, users are free to bring together the components of choice to form their personal assistants.

    While moving around in physical and virtual space, other small computer programs, called guides, can be loaded into the system. Novel, personal services can be created by combining the guide’s understanding of the environment with the personal assistant’s user-specific knowledge.

    To prevent multiple guides from overloading the user, all interactions with the user have to go via a conversation manager. A nightclub-style bouncer administers security, controlling the credentials of guides wanting to enter the system. The use of Internal proxies between components not trusting each other enables malicious or faulty code to be thrown out at any time.

    As a test of concept, a prototype tour guide system for the Exploratory Science Centre in Bristol has been implemented, using Java in Netscape Navigator.

  • 216.
    Eriksson, Marcus
    Linköpings universitet, Institutionen för systemteknik, Kommunikationssystem.
    Analysis of Digital Predistortion in a Wideband Arbitrary Waveform Generator2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Digital predistortion is a signal processing technique used to remove undesired distortions caused by nonlinear system effects. This method is predominately used to linearize power amplifiers in communication systems in order to achieve efficient transmitter circuits. However, the technique can readily be applied to cancel undesired nonlinear behavior in other types of systems.

    This thesis investigates the effectiveness of digital predistortion in the context of a wideband arbitrary waveform generator. A theoretical foundation discussing nonlinear system models, predistortion architectures and system identification methods is complemented with a simulation study and followed by verification on a real system.

    The best predistorter is able to fully suppress the undesired distortions for any fixed two-tone sinusoidal signal. Furthermore, the results indicate the existence of a wideband predistorter which yield acceptable suppression over a frequency range of several hundred MHz.

  • 217.
    Eriksson, Oskar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Signaler och System.
    Error Control in Wireless Sensor Networks: A Process Control Perspective2011Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The use of wireless technology in the process industry is becoming increasingly important to obtain fast deployment at low cost. However, poor channel quality often leads to retransmissions, which are governed by Automatic Repeat Request (ARQ) schemes. While ARQ is a simple and useful tool to alleviate packet errors, it has considerable disadvantages: retransmissions lead to an increase in energy expenditure and latency. The use of Forward Error Correction (FEC) however offers several advantages. We consider a Hybrid-ARQ-Adaptive-FEC scheme (HAF) based on BCH codes and Channel State Information. This scheme is evaluated on AWGN and fading channels. It is shown that HAF offers significantly improved performance both in terms of energy efficiency and latency, as compared to ARQ.

  • 218.
    Eriksson, Ronny
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Webbutveckling för ett mindre företag: Skapandet av en webbplats2012Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Denna rapport innefattar planering och utveckling av en skräddarsydd webbplats för ett mindre företag inriktat på hydraulik. Detta inkluderar de lösningar som gjorts angående webbplatsens funktioner, innehåll, design samt lösningar för vidare administration av webbplatsen.

  • 219.
    Eriksson, Tobias
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Facilitating communication via the Orc protocol: Facilitating communication via the Orc protocol2007Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This master thesis project took place at Orc Software. This company provides technology for advanced trading, market making, and brokerage. The Orc System is based on a client/server architecture. The ordinary way to communicate with the Orc Server System is via the Orc Client Applications, such as Orc Trader or Orc Broker. Additionally, there is another way to communicate with the Orc Server System without using an Orc Client Application. There is a service within the Orc Server System which provides an interface for communication with the Orc Server System. Clients can communicate via this interface using the Orc Protocol (OP).

    Banks and brokers usually have different systems that are specialized for different needs. Often there is a need to integrate these systems with the Orc Server. In order to simplify the integration for customers with modest programming experience in TCP/IP and parsing techniques, Orc Software would like to provide an example parser/generator capable of communication with the Orc Server System free of charge.

    This thesis introduces a toolkit consisting of a parser/generator and a sample application. The application provides several examples as well as serves as verification to the customers of how simple it is to develop their own applications by utilizing the different OP messages.

    A comparison was made between the newly created OP parser/generator and a manually generated FIX client using the FIX gateway which ORC Software AB also sells. This evaluation shows that OP parser/generator is both faster and less memory demanding than the manually generated FIX client.

  • 220.
    Eriksson, Viktor
    Linköpings universitet, Institutionen för systemteknik, Kommunikationssystem. Linköpings universitet, Tekniska högskolan.
    Extraction of radio frequency quality metric from digital video broadcast streams by cable using software defined radio2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The purpose of this master thesis was to investigate how effiecient the extractionof radiofrequency quality metrics from digital video broadcast (DVB) streamscan become using software defined radio. Software defined radio (SDR) is a fairlynew technology that offers you the possibility of very flexible receivers and transmitters where it is possible to upgrade the modulation and demodulation overtime.

    Agama is interested in SDR for use in the Agama Analyzer, a widely deployedmonitoring probe running on top of standard services. Using SDR, Agama coulduse that in all deployments, such as DVB by cable/terrestrial/satellite (DVBC/T/S), which would simplify logistics.

    This thesis is an implementation of a SDR to be able to receive DVB-C. TheSDR must perform a number of adaptive algorithms in order to prevent the received symbols from being significantly different from the transmitted ones. Themain parts of the SDR include timing recovery, carrier recovery and equalization.Timing recovery performs synchronization between the transmitted and receivedsymbols and the carrier recovery performs synchronization between the carrierwave of the transmitter and the local oscillator in the receiver. The thesis discusses various methods to perform the different types of synchronizations andequalizations in order to find the most suitable methods.

  • 221.
    Ernmark, Niklas
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Data- och elektroteknik.
    Utveckling av en CAN-adapter i ett sensorsystem för övervakning av däcktryck.: Development of a CAN-adapter in a sensor system for tire pressure monitoring.2017Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Den här rapporten beskriver ett examensarbete i elektroteknik på Kungliga tekniska högskolan. Syftet var att skapa en unik systemlösning där ett CAN-adapterkort (Controller Area Network) skulle integreras med ett system för övervakning av däcktryck i tunga fordon. Målet var att presentera mätvärden från ventilsensorer på en persondator. Systemet för övervakning av lufttryck heter J1939 – TPMS och är en färdig produkt. J1939 – TPMS skickar CAN-ramar på en CAN-buss i J1939-format. Dessa ramar ska läsas in av adapterkortet och presenteras på ett terminalprogram på en persondator. Arbetet har bestått av att utreda hur systemet J1939 – TPMS fungerar i detalj. Rollen för protokollet J1939 och dess förhållande till CAN har förklarats. Hur J1939-ramar tolkas och hur mätdata rörande TPMS avkodas har beskrivits i detalj. Principer för hur en CAN-nod fungerar har klargjorts. Baserat på detta har ett CAN-adapterkort konstruerats. Konstruktionen har inneburit komponentval, design av elektronikschema, design av mönsterkort och utveckling av inbyggd programvara. Resultatet blev ett färdigt och fungerande CAN-adapterkort som har testats med J1939 – TPMS. Kraven för projektet uppfylldes. Dock så kommer mer arbete med kortet och systemet behövas för att det ska bli en färdig produkt. Arbetet genomfördes hos Motion Control i Västerås AB i samarbete med Transeco Däckservice.

  • 222.
    Ervenius, Johan
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Tysk, Filip
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Dual-mode Capability in a WLAN-equipped PC for Roaming and Mobility between WLANs and GPRS Networks2001Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The goal of this masters thesis work has been to develop and evaluate a solution that enables a WLAN-equipped mobile PC to establish and maintain connectivity by means of cellular network services, and more specifically a GPRS network, when roaming and moving outside the coverage area of a WLAN.

    Both network operators and the software industry are looking for inter-technology roaming solutions that can be implemented with minimal changes to existing infrastructures and standards. We have come to the conclusion that the use of Mobile IP is the solution that best meets these conditions as it is implemented on an IP level and treats wireless LAN and GPRS as peer networks, without any modifications to WLAN or GPRS protocols.

    In addition to the architectural solution efficient mobility is also dependent on the choice of handover algorithm, which decides when to connect to the WLAN and when to connect to the GPRS network. Using studies and measurements we have concluded that a good handover algorithm is vital for good TCP performance when performing a handover between WLAN and GPRS.

  • 223.
    Eslami, Mohammad Zarifi
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    A Presence Server for Context-aware Applications2007Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This master’s thesis project “A Presence Server for Context-aware Applications” was carried out at KTH Center for Wireless Systems (Wireless@KTH). The overall goal of this thesis project is to implement a context aware infrastructure to serve as middleware for different kinds of context aware applications, such as a context-aware printing application, location based notifier application, etc. This thesis examines different types of context aware architectures and considers different forms of context modeling. Additionally the thesis also explores some of the related technology, in order to provide the reader with suitable background information to understand the rest of the thesis. By using the SIP Express Router (SER) and its presence module (pa) a context server has been designed, implemented, and evaluated. Evaluation reveals that the critical bottleneck is the increasing service time as the number of Publish messages for different events in the SER database increases, i.e. the time required for handling and sending the Notify messages when a new Publish message is received increases as a function of the number of earlier Publish messages. The evaluation also shows that the dependence of SER upon the MySQL database as incorrect database queries can cause SER to crash. Additionally the performance of the database limits the performance of the context server. A number of future improvements are necessary to address security issues (in particular the authentication of Watchers) and adding policy based control in order to send Notify messages only to the Watchers authorized to receive information for a specific event.

  • 224.
    Esmael, Muzeyen Hassen
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Modeling Basic Physical Links in Acumen2012Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Simulation is the process of computing a behavior determined by a given model of a system of interest.  Modeling is the process of creating a model that formally describes a given class of system.  Modeling and simulation can be used to quickly and cheaply study and understand new technologies.  Today, a wide range of systems are simulated using different tools.  However, converting models into simulation codes can still be difficult and time consuming.

    In this thesis, we study how a new modeling and simulation language called Acumen can be used to model basic physical links.  This language is aimed at bridging the gap between modeling and simulation.  We focus on basic physical links as an interesting type of system to model and simulate. We also focus on comparing Acumen to MATLAB and Simulink.  The types of links we consider include models of an RC low-pass filter, Amplitude Modulation, Frequency Modulation, Amplitude Shift Keying, Phase Shift Keying and Frequency Shift Keying systems. Each of these examples is modeled in Acumen, MATLAB and Simulink. We find that, for the most part, Acumen allows us to naturally express a wide range of modulation techniques mentioned above. When compared to MATLAB ad Simulink, we find that Acumen is simple language to understand. Acumen codes are described in a more natural way. Simplicity is the biggest advantage of Acumen.

  • 225.
    Evripidis, Romanidis
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Lawful Interception and Countermeasures: In the era of Internet Telephony2008Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Lawful interception and the way it is performed have played a significant role in the effectiveness of this type of communication monitoring. Although the secrecy of interception and the related equipment are supposed to provide correct information to a law enforcement agency, there are some countermeasures that can be taken by the subject that can seriously undermine the collection of correct and accurate data.

    This thesis project attempts to identify the problems that exist for interception of telephony (be it fixed, mobile, or via the Internet). Moreover, there are some suggestions for improvements how lawful interception should be performed in order to avoid possible attacks that could decrease the credibility of the intercepted data. Numerous publications (in print or distributed on the Internet) have described weaknesses in the current state of the art lawful interception when using equipment that can be purchased in the market. This thesis presents improvements in how LI can be conducted in order to avoid these vulnerabilities. Additionally, there is a description of the key escrow systems and the possibility of avoiding one of their most significant vulnerabilities.

    The main problem of the lawful interception is the rapid changes in telecommunications and the complicated architecture of the telecommunication networks, as both make monitoring vulnerable to specific countermeasures. An analysis of how lawful interception can take place and current countermeasures for lawful interception of Internet telephony are vital in order to identify the problems in carrying out such intercepts today and to make suggestions for improvements.

    This topic is especially relevant given the current Swedish “FRA lagen” regarding interception of electronic communication going into, out of, and through Sweden. Not only is it important to understand how lawful interception can be performed or prevented, but it is also important to understand how information obtained from lawful interception could be purposely misleading or falsified.

  • 226.
    Fahad Azeemi, Muhammad
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    HydraNetSim: A Parallel Discrete Event Simulator2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Discrete event simulation is the most suitable type of simulation for analyzing a complex system where changes happen at discrete time instants. Discrete event simulation is a major experimental methodology in several scientific and engineering domains. Unfortunately, a conventional discrete event simulator cannot meet with increasing demands of computational or the structural complexities of modern systems such as peer-to-peer (P2P) systems; therefore parallel discrete event simulation has been a focus of researchers for several decades.

    Unfortunately, no simulator is regarded as a standard which can satisfy the demands of all kinds of applications. Thus while given a simulator yields good performance for a specific kind of applications, it may failed to be efficient for other kinds of applications. Furthermore, although technological advancements have been made in the multi-core computing hardware, none of the mainstream P2P discrete event simulators is designed to support parallel simulation that exploits multi-core architectures. The proposed HydraNetSim parallel discrete event simulator (PDES) is a step toward addressing these issues. Developing a simulator which can support very large numbers of nodes to realize a massive P2P system, and can also execute in parallel is a non-trivial task. The literature review in this thesis gives a broad overview of prevailing approaches to dealing with the tricky problems of simulating a massive, large, and rapidly changing system, and provides a foundation for adopting a suitable architecture for developing a PDES.

    HydraNetSim is a discrete event simulator which allows parallel simulation and exploits the capabilities of parallelization of modern computing hardware. It is based on a novel master/slave paradigm. It divides the simulation model into a number of specific slaves (a cluster of processes) considering the number of cores provided by the underlying computing hardware. Each slave can be assigned to a specific CPU on a different core. Synchronization of the slaves is achieved by proposing a variant of the classic Null-Message Algorithm (NMA) with a focus on keeping the synchronization overhead as low as possible. Furthermore, HydraNetSim provides log information for debugging purposes and introduces a new mechanism of gathering and writing simulation results to a database.

    The experimental results show that the sequential counterpart of HydraNetSim (SDES) takes 41.6% more time than HydraNetSim-2Slave and 23.6% than HydraNetSim-3Slave. HydraNetSim-2Slave is 1.42 times faster, consumes 1.18 times more memory, and supports 2.02 times more nodes than a sequential discrete event simulator (SDES). Whereas, HydraNetSim-3Slave executes 1.24 times faster, consumes 2.08 times more memory, and supports 3.04 times more nodes than SDES. The scaling factor of HydraNetSim is ⌈(β-1)*102.04%⌉ of the maximum numbered of nodes supported by SDES; where β is the number of slaves.

  • 227.
    Fahlborg, Daniel
    Linköpings universitet, Institutionen för systemteknik, Kommunikationssystem.
    Measuring one-way Packet Delay in a Radio Network2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Radio networks are expanding, becoming more advanced, and pushing the limits of what is possible. Services utilizing the radio networks are also being developed in order to provide new functionality to end-users worldwide. When discussing 5G radio networks, concepts such as driverless vehicles, drones and near zero communication delay are recurrent. However, measures of delay are needed in order to verify that such services can be provided -- and measuring this is an extensive task. Ericsson has developed a platform for simulating a radio environment surrounding a radio base station. Using this simulator, this project involved measuring one-way packet delay in a radio network, and performing a Quality of Service evaluation of a radio network with a number of network applications in concern. Application data corresponding to video streams, or Voice over IP conversations, were simulated and packet delay measurements were used to calculate and evaluate the Quality of Service provided by a radio network. One of the main conclusions of this project was that packet delay variations are asymmetric in uplink, which suggests usage of non-conventional jitter measurement techniques.

  • 228.
    Falgert, Marcus
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Geo-distributed application deployment assistance based on past routing information2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Cloud computing platforms allow users to deploy geographically distributed applications on servers around the world. Applications may be simple to deploy on these platforms, but it is up to the user and the application to decide which regions and servers to use for application placement. Furthermore, network conditions and routing between the geo-distributed servers change over time, which can lead to sub-optimal performance of applications deployed on such servers.

    A user could either employ a static deployment configuration of servers, or attempt to use a more dynamic configuration. However, both have inherent limitations. A static configuration will be sub-optimal, as it will be unable to adapt to changing network conditions. A more dynamic approach where an application could switch over or transition to a more suitable server could be beneficial, but this can be very complex in practice. Furthermore, such a solution is more about adapting to change as it happens, and not beforehand.

    This thesis will investigate the possibility of forecasting impending routing changes between servers, by leveraging messages generated by the Border Gateway Protocol (BGP) and past knowledge about routing changes. BGP routers can delay BGP updates due to factors such as the minimum route advertisement interval (MRAI). Thus, out proposed solution involves forwarding BGP updates downstream in the network, before BGP routers process them. As routing between servers changes, so does the latency, meaning that the latency then could be predicted to some degree. This observation could be applied to realize when the latency to a server increases or decreases past another server. This in turn facilitates the decision process of selecting the most optimal servers in terms of latency for application deployment.

    The solution presented in this thesis can successfully predict routing changes between end-points in an enclosed environment, and inform users ahead of time that the latency is about to change. The time gained by such predictions depend on factors such as the number of ASs between the end-points, the MRAI, and the update processing delay imposed on BGP routers. Time gains between tens of milliseconds to over 2 minutes has been observed.

  • 229.
    Falk Drugge, Anna Elisabet
    KTH, Tidigare Institutioner, Teleinformatik.
    User Centered Communicating Devices1997Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    The extensive use of communicating computers in the future will require the development of products and services that are easy to use. With this in mind a literature study has been done. The report presents examples of current and some visions of future human centered communication devices. They are described from three different aspects: human, societal, and technical.

    In the section on the human aspect three different classes of interfaces are described: unnoticeable, intuitive, and social. The intention with the section on the societal aspect is to give examples of how different social institutions will change and the new possibilities those changes will bring. In the technology section new development and research are presented in the areas of input/output devises, networks, and power supply.

    The intention with this report is not to cover all possibilities or to present solutions, instead the aim is to serve as a source of inspiration and provide food for thought.

  • 230.
    Falk, Mikael
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Fernandez Karlsson, Matias
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Driftövervakning av Windows och Linux/Unix Servrar2008Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Ju fler servrar, med olika konfigurationer och olika system, som blir medlemmar i ett nätverk, desto svårare och osmidigare blir det att övervaka nätverksmiljön. Men om man använder sig av ett övervakningssystem, som tar emot information från flera servrar, blir det lättare att få en överblick om hur allt fungerar och samtidigt som det går snabbare att få information om felmeddelanden, som man sedan kan åtgärda.

    I detta dokument tar vi upp olika typer av övervakningssystem som finns ute på marknaden idag, våren 2008. Bland dessa hittar vi t.ex. SCOM 2007, BigBrother, Nagios och Mon. Vi har inte begränsat oss till ett specifikt operativsystem, utan vi tar upp övervakningssystem som passar till Windows och/eller Linux/Unix.

    Utifrån den information vi hittat om varje övervakningssystem och de kriterier som Valderas Consulting AB vill att systemen ska uppfylla, har vi valt ut tre stycken övervakningssystem som vi tycker passar bäst. Dessa system har vi sen, ett och ett, testat i ett litet nätverk där vi utsätter det för en del scenarior som kan hända ute på företag som t.ex. trasig anslutning, för full hårddisk och kraschat operativsystem.

    De tre övervakningssystem vi tyckte höjde sig över mängden var SCOM 2007, Big Brother 4 och Nagios. Efter att ha testat vart och ett av dessa tre tycker vi att Nagios är det klart bästa. Det är användarvänligt i installationen, konfigurationen samt i övervakningen. En annan stor fördel med Nagios är att det är gratis, dvs. open source. Om ens datormiljö enbart innehåller Windows-datorer och en domän, passar SCOM 2007 bäst, då Nagios måste installeras på en Linux/Unix-dator. Big Brother 4 var bra det med, men faller bort pga. att det inte är gratis, färre testmöjligheter på nätverket och fungerade inte helt bra med att övervaka Linux/Unixdatorer.

  • 231.
    Fatollahy, Masoud
    KTH, Tidigare Institutioner, Teleinformatik.
    ISP Selectivity Using NAT1998Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This document describes Network Address Tra nslation and investigates the possibilities of using NAT on an Edge Rouer to provide ISP slectivity for the users, and describes an implementation of NAT on Ericssson's AX51x Edge Router. The reasons for allowing users to slect their ISP are that, customers may change providers, customers may utilize different ISPs for different services, company backbones may be reorganized, or providers may merge or split. This document also briefly describes other areas that are relevant to this task.

  • 232.
    Fawzy Kamel, Menatalla Ashraf
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Vendor Lock-in in the transistion to a Cloud Computing platform2015Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The thesis introduces a study about the vulnerabilities that a company as Scania IT faces towards vendor lock-in in the transition to a cloud computing platform. Cloud computing is a term that refers to anetwork of remote servers hosted on the internet to store, manage and process data, rather than on a local server or a personal computer. Vendor lock-in is an outcome that causes companies to pay a significant cost to move between cloud providers. The effects that cause vendor lock-in that will be described are portability, interoperability and federation are called the lock-in effects. The goal of the research is to help Scania IT understand the vendor lock-in and the vulnerabilities they can face in the transition to the cloud as well as to clarify the concern that they may have against falling in vendor lock-in. The main purpose of the research is to present the various lock-in effects that are related to the transition from one cloud provider to another and the vulnerabilities that cause companies to fall in vendor lock-in. The thesis presents the reasons that motivates why Scania IT would consider using the cloud and the concerns that they may have against usage of a cloud computing platform. The results will be based on a case study of a similar company that has moved to a cloud provider and specifically Microsoft Azure and an interview of Microsoft Azure point of view with the risk of vendor lock-in. Finally, a process of interviews with different people from Scania IT to extract the current bottleneck in the development process that caused the company to think of a cloud computing platform. The results show that companies should consider many risks and factors while moving to the cloud, as vendor lock-in, cloud maturity index and their IT strategies. As a result, the thesis gives recommendations of the steps needed to minimize the risks of the cloud while maintaining the positivity of the cloud.

  • 233.
    Faxén, Linnea
    Linköpings universitet, Institutionen för systemteknik, Kommunikationssystem.
    A Study on Segmentation for Ultra-Reliable Low-Latency Communications2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    To enable wireless control of factories, such that sensor measurements can be sent wirelessly to an actuator, the probability to receive data correctly must be very high and the time it takes to the deliver the data from the sensor to the actuator must be very low. Earlier, these requirements have only been met by cables, but in the fifth generation mobile network this is one of the imagined use cases and work is undergoing to create a system capable of wireless control of factories. One of the problems in this scenario is when all data in a packet cannot be sent in one transmission while ensuring the very high probability of reception of the transmission. This thesis studies this problem in detail by proposing methods to cope with the problem and evaluating these methods in a simulator. The thesis shows that splitting the data into multiple segments and transmitting each at an even higher probability of reception is a good candidate, especially when there is time for a retransmission. When there is only one transmission available, a better candidate is to send the same packet twice. Even if the first packet cannot achieve the very high probability of reception, the combination of the first and second packet might be able to.

  • 234.
    Faxér, Sebastian
    Linköpings universitet, Institutionen för systemteknik, Kommunikationssystem. Linköpings universitet, Tekniska högskolan.
    Self-optimization of Antenna Sectorization2014Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Sectorization is a well-established method of increasing the capacity of telecommunicationnetworks. With modern Active Antenna Systems (AAS) comes the abilityto change sectorization order dynamically, both in horizontal and vertical plane.The purpose of this thesis is to investigate when (and what type of) sectorizationis benficial. A theoretical analysis as well as simulations are performed in orderto determine which quantities to look at when making the decision to apply sectorization.Based on the conclusions from these investigations, a self-optimizingalgorithm that only turns on sectorization when it increases network performanceis developed and evaluated. It is shown that large gains can be achieved by onlyturning on sectorization when the right conditions are met. Further, we show thatadditional gains can be seen if antenna parameters such as downtilt and distributionof transmission power between sectors are set properly. Self-optimizingalgorithms for tuning of these parameters are developed and evaluated as well.NyckelordKeywords

  • 235.
    Feng, Xuan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Evaluation of Capuchin Application Programming Interface: Implementing a Mobile TV Client2009Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The purpose of this research was to evaluate the Capuchin API launched by Sony Ericsson at Lund, Sweden in 2008. The Capuchin API bridges Adobe’s Flash graphics and effects with JSR support from Java ME. We evaluated Capuchin API with regard to its suitability for a Mobile TV application. We tested this API in Ericsson’s TV lab where we had access to live TV streams and online multimedia resources by implementing a Mobile TV client. This test application was named “Min TV”, in English: “My TV”.

    Using Capuchin in the Ericsson TV lab environment has shown that it has some benefits, but also has many drawbacks. The Flash developer can be used to create an animated user interface and Java developers can do complex programming. At this early stage Capuchin technology is not mature enough, nor is it suitable for Mobile TV client development. Only after Sony Ericsson adds features such as soft keys, easier debugging of Flash Lite standalone applications, test emulator support in the software development kit, and more data communication methods than string and number, only then it will be a suitable technology for Mobile TV applications.

    Ericsson’s current Mobile TV application client was built using a framework called ECAF, which supports a graphics frontend and Java ME as backend. We compared ECAF and Min TV with respect to parameters such as: flexibility, performance, memory footprint, code size, and cost of skinning. (All these parameters are explained in detail in the methodology chapter.)

    As a possible future technology for Mobile TV, we evaluated a number of different presentation/graphics technologies including HECL, SVG Tiny, MIDP 3.0, .NET Compact Framework, etc. Moreover, we examed if a pure Flash Lite client application is a viable solution for Mobile TV. The comparison of different presentation technologies showed that Java ME is a comprehensive platform for mobile development offering all the necessary support from third party graphical user interface makers. .NET CF also looks like a good option for development with the scaled down capabilities for different programming languages supported using CLR.

  • 236.
    Fernández, Alexis Martínez
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Authorization schema for electronic health-care records: For Uganda2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This master’s thesis project began at the Karolinska University Hospital. This thesis discusses how to design an authorization schema focused on ensuring each patient’s data privacy within a hospital information system. It begins with an overview of the current problem, followed by a review of related work. The overall project’s goal is to create and evaluate an authorization schema that can ensure each patient’s data confidentiality.

    Authorization has currently become a very important aspect in information systems, to the point of being a necessity when implementing a complete system for managing access control in certain complex environments. This requirement lead to the approach that this master thesis takes for effectively reasoning about authorization requests in situations where a great number of parameters could affect the access control assessment.

    This study is part of the ICT4MPOWER project developed in Sweden by both public and private organizations with the objective of improving health-care aid in Uganda through the use of information and communication technologies.  More concretely, this work defines an authorization schema that can cope with the increasing needs of sophisticated access control methods where a complex environment exists and policies require certain flexibility.

  • 237.
    Fey, Enikö
    KTH, Tidigare Institutioner, Teleinformatik.
    The Effect of Combining Network and Server QoS Parameters on End-to-End Performance2000Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Application hosting is becoming a popular business, Application Service Providers (ASPs) need however to keep up with the increasing pace of the market. This implies that they have to provide infrastructure to an increasing number of clients, and at the same time give QoS guarantees to these clients. One solution for ASPs to both guarantee a certain service level (QoS) for their clients and keep expanding would be to have so many resources as to be able to provide more than the maximum aggregate need of their clients. This may turn out to be an expensive or even an impossible solution - sharing infrastructure between clients and offering some means of resource reservation, and using charging to insure that clients only reserve the resources they need, is an alternative.

    It is however not an easy problem to solve, particularly if the procedure of adding new clients is to be automated, and the resources dynamically allocated. The ICorpMaker framework being developed at the IBM Zurich Research Laboratory offers a solution to the above named problems. In the ICorpMaker framework dynamic resource allocation is achieved by letting clients modify the amount of resources allocated to them in a simple manner, requesting more or less resources than their current allotment.

    The difficulty in achieving the end-to-end performance the client desires, lies in the fact that it is not certain how modifying resource allocation at the network respectively server level will combine and affect the end-to-end performance experienced by the end users of the service. The aim of this thesis project was to study the correlation between different network and server QoS parameters and the resulting end-to-end performance by making measurements. The results obtained from these measurements give an answer to the question of how to change the network and server resource allocations, when a client's application does not perform in a satisfactory way and hence the client requests more resources. Certain optimizations for the resource (re)allocation were also suggested based on the results.

  • 238.
    Fey, Zsuzsa
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Adapting and Optimising TCP/IP on Satellite Networks2001Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Today communication has become an essential part of our lives. As communication becomes even more global, one has to search for new communication forms, which can satisfy the new needs of the customers. One emerging area is communication via satellites. As the TCP/IP protocol family is the most used protocol family in today's Internet, but was developed primarily for communication on wired links, it has suboptimal behaviour when used with satellite links.

    The purpose of this master's thesis is to examine the shortcomings of using the TCP/IP protocol suite on satellite links, to see what types of problems occur in satellite communication, how these problems affect TCP/IP and to try to find solutions to the problems found.

    The thesis begins with a presentation of the TCP/IP protocols and the issues regarding satellite communications, more precisely the DVB-RCS standard. Then we will take a look at existing improvements for TCP/IP communication over satellite links. The main part of the thesis is to study the behaviour of the different implementations of the TCP/IP protocolson satellite links and to examine possible improvements.

    Finally there are presented the conclusions drawn. The experiments showed that better performance is achieved for initial congestion window sizes of 3 or 4. It was also seen a performance discontinuity at return channel bandwidth of 512 kbps. At low BER TCP Reno performed best, while at high BER no general behaviour was seen. However, at high BER TCP SACK or TCP FACK performed best in most of the studied cases.

  • 239.
    Filimonovic, Martin
    KTH, Tidigare Institutioner, Teleinformatik.
    Voice over IP - SIP client1999Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    The interest in utilizing the Internet for real-time communication has grown substantially in recent years. This thesis covers the features of Voice over IP and IP telephony and the signaling protocols used for establishing and terminating calls over the Internet

    Two signaling protocols will be compared, SIP from IETF and H.323 from ITU. A deeper investigation of SIP was made, with the purpose of making a small implementation of a SIP client for point to point communication. Two different approaches were developed. The report will also outline the comparisment of SIP and H.323 and the evaluation of the SIP user agents.

  • 240.
    Folke, Fredrik
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Security for home, small & medium sized enterprises IPv6 networks: Security using simple network equipment2012Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    This theses project investigates and presents different threats that a network can be exposed to and the common protection techniques that can be applied, with a focus on the network perimeter – specifically the router/firewall between the local area network and the Internet. All Internet connected devices and networks are exposed to and affected by security threats to some degree, hence security is important in almost every type of network. With the constant growth of the Internet the 32-bit addressing scheme ipv4 is proving to be inadequate, and therefore the transition to the 128-bit addressing scheme ipv6 is becoming critical. With ipv6 comes new security threats (while still old threats remain) that requires an understanding of perimeter security. In this thesis we secure a home router and describe these steps to enable home and small business owners to secure their IPv6 network at a relatively low cost.

  • 241.
    Forsberg, Joakim
    KTH, Tidigare Institutioner, Teleinformatik.
    HTTP in a Realtime OS1999Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Web servers are today found in devices that no one could imagine a couple of years ago. At that time people asked themselves who would use a Web server at all. Today the questions is why would anyone put a Web server in an embedded device? But that is actually what is happening right now. Today te industry is trying to webify virtually everything from banking errands to our homes. This developmnet has lead to the fact Hypertext Transfer Protocol (HTTP) servers, ofen referred to as a Web server, are found in almost all the devices that can be hooked to a network. Therefore it is quite natural to study f a Web server could be used in an embedded systems link AXE 10. The real question is probably: Is it feasible to have a server in the operating system EriOS? The answer is that a Web server can be used, but it might be better to use a SNMP server in the AXE10 and a Web server outside the AXE10. In this case SNMP would be used to query the AXE10. EriOS is an operating system that is written in the language EriPascal.

  • 242.
    Forsell, Erik
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Internet Telephony: An Internet Service Provider's Perspective2005Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The aim of this Masters Thesis is to propose to SYSteam Nät AB, a local Internet Service Provider (ISP) in Uppsala, Sweden, how to implement IP telephony in their existing ITinfrastructure as a service to their customers. Thus the perspective of the thesis will be that of a local Internet Service Provider. Three general areas are covered in the thesis: Market and Business Model, Technology, and Economics.

    Important issues for SYSteam Nät AB as an established local broadband Internet Service Provider are to both retain present customers and to attract new customers. Some believe that offering value added services such as IP telephony could do this.

    Implementation of IP telephony can be done in different ways to fulfil SYSteam Nät’s requirements. The analysis leads to a proposal of how SYSteam Nät could implement IP telephony. This involves many multi-faceted business, technical, and financial issues; each aspect is examined in this thesis.

  • 243.
    Forte, Paolo
    KTH, Skolan för elektro- och systemteknik (EES), Kommunikationsnät.
    Predicting Service Metrics from Device and Network Statistics2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    For an IT company that provides a service over the Internet like Facebook or Spotify, it is very important to provide a high quality of service; however, predicting the quality of service is generally a hard task. The goal of this thesis is to investigate whether an approach that makes use of statistical learning to predict the quality of service can obtain accurate predictions for a Voldemort key-value store [1] in presence of dynamic load patterns and network statistics. The approach follows the idea that the service-level metrics associated with the quality of service can be estimated from serverside statistical observations, like device and network statistics. The advantage of the approach analysed in this thesis is that it can virtually work with any kind of service, since it is based only on device and network statistics, which are unaware of the type of service provided.

    The approach is structured as follows. During the service operations, a large amount of device statistics from the Linux kernel of the operating system (e.g. cpu usage level, disk activity, interrupts rate) and some basic end-to-end network statistics (e.g. average round-trip-time, packet loss rate) are periodically collected on the service platform. At the same time,

    some service-level metrics (e.g. average reading time, average writing time, etc.) are collected on the client machine as indicators of the store’s quality of service. To emulate network statistics, such as dynamic delay and packet loss, all the traffic is redirected to flow through a network emulator. Then, different types of statistical learning methods, based on linear and tree-based regression algorithms, are applied to the data collections to obtain a learning model able to accurately predict the service-level metrics from the device and network statistics.

    The results, obtained for different traffic scenarios and configurations, show that the thesis’ approach can find learning models that can accurately predict the service-level metrics for a single-node store with error rates lower than 20% (NMAE), even in presence of network impairments.

  • 244.
    Franson, Johan
    KTH, Tidigare Institutioner, Teleinformatik.
    Personal Information Services: seen from an Agent perspective1997Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This report approaches information services in an agentoriented way. First the concept of an ”agent” is discussed anddefined. Then an information world model is build. This modeltries to focus on information content, services, and users. Withthis model and the agent concept as tools, services such as, e.g.,call screening, mailboxes, notification, news services, messagetranslation, coordination of a user’s terminals, etc. arediscussed. The goal of this report is to inspire the reader tothink in an agent oriented way, rather than stating some kind ofultimate solution.

  • 245.
    Fransson, Emelie
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Driving behavior modeling and evaluation of merging control strategies - A microscopic simulation study on Sirat Expressway2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Bangkok is a city where the congestion levels have been a major problem for many years. In 2017, Bangkok was rated the most congested city in Asia, and the second most congested in the world. According to The Expressway Authority of Thailand (EXAT), on-ramp merging is one of the most critical problem that causes congestion on the urban expressways. EXAT have evaluated several merging control strategies through microscopic traffic simulation to find suitable strategies for implementation in real life. However, their simulation studies were all based on the assumption that all motorists strictly follow the traffic rules. This is not the actual case in Bangkok, where the drivers ignore both solid lines and striped areas, as well as utilize the shoulder lane on a regular basis. The aim of this thesis is to investigate if it is possible to include this complex driving behavior in existing microscopic simulation models. A second objective is to identify merging control strategies that can reduce the occurrence and the effects of this driving behavior in order to increase the throughput at an on-ramp area on Sirat Expressway. A model was built in VISSIM and calibrated based on data collected from video recordings. In the study, parameters that are significant for the driving behavior modeling, as well as the difficulties that arise from performing a realistic calibration of the model using video observations and model-specific constraints, are identified. From the video recordings it was discovered that the main problem causing the congestion was a result of the mainline traffic who traversed to the on-ramp. Two merging control strategies were suggested to address this problem: the installment of a center barrier, and successive merging areas. The results confirmed that both actions can improve the traffic situation in terms of reducing the individual travel time. Installing a center barrier was the most efficient option and reduced the travel time by 16.58 % on the mainline and 63.24 % at the on-ramp.

  • 246.
    Fredén, Magnus
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Mobile Internet: Testing of Internet services2005Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In addition to the problems that may occur in the Internet, the people who test mobile internet services confront additional challenges due to the wireless environment. If something goes wrong, it is very problematic for a tester to determine exactly where the error occurred and the reason why it occurred. Is it the software in the telephone that does not work properly, is the GPRS link stable, is the core network of the Internet working as it should, or is there something wrong at the server? The staff at Sony Ericsson has major difficulties determining where the origin of a problem is. They often simply know that something is not working. The major effort is often to detect the source of the actual problem rather than solving it.

    The PlayNow service provided by Sony Ericsson will be used as a reference service in this master’s thesis project. The PlayNow service is currently used for distributing ring signals. It is built on Internet standards, but depends on GSM’s specific features both for distribution and for e-commerce which makes it hard to test using existing web test tools. This Master’s Thesis examines the difficulties in establishing robust IP traffic links between a server and a mobile telephone. It examines the entire communication path between the mobile telephone and the server, and focus on how to detect (potential) errors. Within this project, development of a test tool is included. It supports features necessary for testing the reference service PlayNow.

    This report covers many different technologies within the mobile internet such as GSM, GPRS, and mobile IP. Moreover, the normal infrastructure of the Internet will also be considered; as well as how the different parts interact in an environment consisting of a mobile Internet with GPRS. A major part of the project has been evaluation of the communication link between a mobile device and a server. Additionally, some efforts have focused on developing the new test tool.

  • 247.
    Friðriksson, Vilhelm
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Container overhead in microservice systems2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Containers have been gaining popularity in recent years due to their ability to provide higher flexibility, higher reliability and dynamic scalability to enterprise software systems. In order to fully utilize containers, software developers aim to build their software using microservice architecture, meaning that instead of working on a single large codebase for the whole project, the software is split into smaller units. These microservices can be deployed in their own container instead of the traditional virtual machine setup where a server has to configured with all necessary dependencies. Moving away from the monolithic software architecture to containerized microservices is bound to bring performance penalties due to increased network calls between services and container overhead. The integration must therefor be carefully planned in order to fully utilize the container setup while minimizing the overhead. The purpose of this thesis project was to measure how much overhead can be expected due to containers in an enterprise environment. By using a combination of virtual machines and Docker containers, a microservice system was deployed with four different deployment strategies and the system’s performance was measured by analyzing request response times under various loads. The services were made to run on a single server and on multiple servers, with and without Docker. The performance measurements showed that the system performed worse in every case when Docker was used. Furthermore, the results showed that Docker can have significant negative impact on performance when there is a heavy load on the system.

  • 248.
    Frostensson, Tomas
    Linköpings universitet, Institutionen för systemteknik, Kommunikationssystem. Linköpings universitet, Tekniska högskolan.
    Hardware Implementation and Assessment of a Soft MIMO Detector Based On SUMIS2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    To allow faster and more reliable wireless communication a technique is to use multiple antennas in the transmitter and receiver. This technique is called MIMO. The usage of MIMO adds complexity to the receiver that must determine what the transmitter actually sent. This thesis focuses on hardware implementation suitable for an FPGA of a detection algorithm called SUMIS.

    A background to detection and SUMIS in particular is given as a theoretical aid for a better understanding of how an algorithm like this can be implemented. An introduction to hardware and digital design is also presented.

    A subset of the operations in the SUMIS algorithm such as matrix inversion and sum of logarithmic values are analyzed and suitable hardware architectures are presented. These operations are implemented in RTL hardware using VHDL targeted for an FPGA, Virtex-6 from Xilinx.

    The accuracy of the implemented operations is investigated showing promising results alongside of a presentation of the necessary resource usage.

    Finally other approaches to hardware implementation of detection algorithms are discussed and more suitable approaches for a future implementation of SUMIS are commented on. The key aspects are flexibility through software reprogrammability and area efficiency by designing a custom processor architecture. 

  • 249.
    Frostne, Isabel
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Traffic analysis of existing traffic in Kulyab region in order to plan and configure a new GSM MSC for this region2011Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Wide area cellular mobile networks have rapidly evolved over the years. In the beginning achieving wide area coverage was a great achievement – enabling subscribers to call from wherever they were currently located and whenever they wanted. Additionally these systems supported mobility of subscribers, so that calls could continue even while a subscriber moved from one cell to another. Today mobility management is something everyone takes for granted. New functionality is continuously being developed for these networks. An important aspect of this evolution has been to enable new applications and technologies to be introduced while maintaining interoperability with the existing technologies.

    These mobile networks use new technologies and enable new applications, but they interconnect with existing networks that utilize earlier technologies, such as the existing fixed telephone network. These interconnections enable communication between subscribers connected via all of these networks. In today’s mobile networks there are a variety of technologies working side by side, for example 2G, GPRS, 3G, and so on. The earlier networks used circuit switching technology, but the trend in later networks was to transition exclusively to packet switching.

    One of the most important network entities is the mobile switch center (MSC). In the earlier circuit switched networks the MSC is the heart of the circuit switching network. The MSC is responsible for management, control, and communication to and from the mobile stations (MSs) in the area managed by the MSC. The MSC stores information about each of the MSs in one or more databases. In the subscriber’s home network the information about their subscription is stored in a home location register (HLR), while when this subscriber is in another network information is stored in a visitor location register (VLR). The MSC together with other elements of the core network handles mobility management, enabling both handover and roaming. A gateway MSC enables MSs to communicate with phones connected to the fixed network.

    The aim of this thesis is to analyze the traffic situation for Kulyab region in order to configure and install the MSC in Kulyab. For the time being there is no radio network controller (RNC) in Kulyab region, so the MSC in Kulyab will be configured to support 2G traffic.

    The configuration will be based on the expected mobile traffic load in the Kulyab region, thus the first steps in the process were to collect and analyze data about the existing traffic in this region that is currently served by a MSC located outside of this region. The configuration of the new MSC will be based on this analysis.

    After installing and configuring the new MSC some question need to be answered, namely:

    1. Can the MSC in Kulyab support all the base stations in Kulyab region? If not, how many base stations can it support?
    2. To what extent does the addition of this new MSC improve the overall network in terms of increased reliability, capacity, and throughput?
    3. How much will the capacity of the existing MSC, that is responsible for traffic outside Dushanbe, be increased due to the introduction of the new MSC?
  • 250.
    Fu, Qiang
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Building models of Wireless Local Area Network coverage2007Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Wireless LANs are becoming more and more popular because they can provide high data rate network access to computer users without the tradition cable. Additionally mobile devices allow people to have connectivity, even when moving from place to place, additionally they are small in size and light in weight. While such devices only offer some of the capabilities of PC they are more convenient to use than a desktop PC when traveling. Cellular phone and smart phones have more function than before, with some newer models phone having an embedded GPS receiver. This GPS receiver can provide user with new services, in addition to location information. Many of these handheld devices include wireless LAN functionality, enabling people to walk from one place to another with a continuous network access, via either the WLAN or the cellular network. By using voice over IP, a wireless enabled hand device becomes a Virtual Cell Phone enabling low cost calls via the WLAN when the user is within coverage of an access point which will give them access, or via the normal cellular phone network (when with in coverage).

    Because the WLAN coverage is not ubiquitous, it is important to build a Wireless Network Coverage model to enable every user to see where there is WLAN network coverage. Present methods to create such a coverage map require a lot of work to collect data, both indoors and outdoors. Currently a lot of human effort is needed to collect, process, and format this data. The method proposed her could provide an easier way of gathering data from the field and be simple enough that even a normal user could collect data and contribute it to help generate a coverage model of areas where they visit.

    The measurements reported indicate that it is possible to combine data from multiple devices of the same and different types, but only when the signal strength is high. Fortunately, it is just these areas where the signal quality is good which are of interest to users. The thesis also shows one way of presenting this data in an easy to understand visual manner as an overlay on Google Earth.

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