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  • 101.
    Byttner, Anders
    KTH, Tidigare Institutioner, Teleinformatik.
    Internet Telephony using the Session Initiation Protocol2000Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The Session Initiation Protocol (SIP) is a highly extensible signaling protocol that provides mechanisms for establishing, modifying, and tearing down Internet telephony calls. Together with other Internet protocols and API’s it can create a flexible, dynamic, and scalable telephony environment, where services can be developed and deployed rapidly and by a wide range of users.

    This report investigates some proposed extensions to SIP and some of the API's that aim to standardize how telephony services can be defined in a SIP enabled network. The report describes some changes and improvements to these proposals and demonstrates how different services can be implemented using them.

  • 102.
    Börjesson, Martin
    KTH, Tidigare Institutioner, Teleinformatik.
    Creation & Deployment of Voice Browsing Services1999Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Making the World Wide Web accessible trough audio interfaces (voice browsing) would provide many benefits. Far more people today have access to phones than have access to computers, further more, cellular phones allow user-mobility. Traditional Interactive Voice Response (IVR) applications have so far been restricted to the POTS network. However, a combination of Internet and IVR technologies could make voice browsing on the WWW possible. IVR services can with many benefits be described with customised markup languages instead of the traditional programming languages that are used today. The services can be published on the web using the same tools as in graphical Web publishing.

    In this paper, existing conversational markup languages are presented and evaluated together with suggestions for improvements. The benefits of the Extensible Markup Language in web publishing are studied with the conclusion that it would provide the best available base a future conversational markup standard.

    Requirements for a voice browser are suggested and possible media platforms are evaluated and discussed. The design of a voice browser is presented and discussed together with experiences gained from an implementation task.

    This paper concludes that voice browsing on the WWW will become a common way of web interaction within a not too distant future. The techniques necessary already exists. The benefits and opportunities that it offers will drive the development of necessary standards as well as the growth of content provide[r]s and users[.]

  • 103.
    Bülow, Jonas
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Mobile IP and AAA Services2002Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Networks providing Authentication, Authorization and Accounting services are found all over the world. The number of mobile devices is growing rapidly and the need to have a seamless, user friendly, and stable integration between mobile devices and AAA enabled networks is an important development trend right now.

    This thesis will give an overview of the work taking place in the field of AAA and Mobile IP. Issues when Mobile IP and AAA meet will be discussed.

    The thesis will describe sample tests of a Mobile IP network and a simple test using the forthcoming AAA protocol Diameter.

    Conclusions based on these tests are described along with some obvious future work.

  • 104. Caballero Bayerri, Juan
    et al.
    Malmkvist, Daniel
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Experimental Study of a Network Access Server for a public WLAN access network2002Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Wireless access networks have gained popularity due to the flexibility they allow the user, who is able to move away from his or her desk while still being able to access information. Among the different Wireless LAN standards, the most widespread, by far, is IEEE 802.11.

    Public WLAN access networks are being set up in hotspots, i.e. areas expected to have high demand for bandwidth. Access to the Internet and to corporate networks is provided at these hotspots with limited coverage but high available bandwidth. Airports and hotels have often been the first targeted locations for these hotspots, but conference centres, cafes, and train stations follow. In the near future, any person who owns at least one access point and has a connection to the Internet can become a small operator and offer access to the Internet using these resources.

    Existing solutions for such WLAN access networks lack support for security, flexible accounting, mobility, multiaccess, roaming and user-friendly login. The aim of this Master's Thesis was to study if it was possible to solve these problems and how to integrate all this new functionality into existing public WLAN access networks by building and evaluating a prototype of a public WLAN access network

    System requirements were defined, currently available solutions analysed and a prototype was built. Most of the functionality of the prototype is placed in the Network Access Server, which is the main element providing security, mobility, and accounting.

    Flexible accounting, improvements in security, an easy and fast way to login the user, a feedback module to provide information about the current session and integration of the RADIUS architecture with the Mobile IP distribution have all been implemented.

  • 105.
    Cabarkapa, Dragan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Authorization Architecture for SWoT2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Social Web of Things (SWoT) is a user centric framework which facilitates interaction between software agents deployed on smart things and in the cloud. Software agents deployed on smart things are remotely accessible, host sensitive resources, and often represent high value targets. SWoT currently does not feature adequate security mechanisms which could protect software agents from unauthorized access. In this thesis, we aim to rectify this deficiency by introducing platform independent, exible, and user centric authorization mechanism inSWoT.

    We derive requirements and design of abstract authorization architecture from the preceding seminal work performed in SENSEI project. SENSEI and SWoT share same problem domain, but while SENSEI addresses enterprise use cases SWoT focusses on consumer use cases. This single but fundamental difference motivates adaptations of SENSEI contributions for application in SWoT. To realize concrete authorization architecture we perform extensive study of various authorization solutions. Results of our study indicate that novel User Managed Access (UMA) protocol represents promising solution for SWoT.

    We present the Authorization as a Service solution for SWoT framework, based on UMA protocol. This solution enables users to manage and control communication between software agents deployed on smart things and in the cloud from single centralized location. It also features runtime association of software agents, management, evaluation, and enforcement of access permissions for resources provided by software agents.

  • 106.
    Cao, Wei Qiu
    KTH, Tidigare Institutioner, Mikroelektronik och informationsteknik, IMIT.
    A new Content Distribution Network architecture - PlentyCast2004Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Content Distribution Networks have existed for some years. They involve the following problem domains and have attracted attention both in academic research and industry: content replica placement, content location and routing, swarm intelligence, and overlay network self-organization for this type of distributed system. In this project, we propose a novel Content Distribution Network architecture – PlentyCast. This study focuses on improving access latency, network scalability, high content availability, low bandwidth consumption, and improving infrastructure performance for Content Distribution Networks. Outstanding problems such as: Flash crowd, DoS, and difficulty of traffic engineering due to Peer-to-Peer are addressed.

  • 107.
    Carls, Johan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    NGN – Nästa Generations Nätverk (Nätverks- och Riskanalys) för Piteå Kommun2015Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Mitt uppdrag har varit att tekniskt dokumentera och kartlägga Piteå Kommuns befintliga Nätverksinfrastruktur. Allt har sedan sammanfattats i flera olika områden: Nätverkstjänster, Nätverksnäratjänster, Teknik, Hantering/Styrning och Säkerhet. En Riskanalys har sedan tagits fram där jag har identifierat totalt 28 risker och brister i kommunens befintliga nätverksinfrastruktur. 4st under Design, 9st under Säkerhet, 5st under Nätverksnäratjänster, 2st under Nätverkstjänster, 2st under Hantering/Styrning och 5st under Teknik. Alla risker och brister har kategoriserats i prioritetsordning liten, mellanstor och stora risker samt brister med varierad åtgärdstid (0-24+ månader). Denna Slutrapport har varit underlag för att sedan ta fram en ny framtidssäkrad Nätverksinfrastruktur med hjälp av en Krav- och Målbild för Piteå Kommun.

  • 108.
    Carlsson, Daniel
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Dynamics AX in the Cloud: Possibilities and Shortcomings2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The usage of the cloud is rapidly increasing and is something that is of large interest to everyone involved in technology. The purpose of this thesis is to examine the benefits and possible shortcomings of using Microsoft Dynamics AX in the cloud, specifically Microsoft Azure, instead of using local datacenters. This thesis project has been done at Scania IT using their implementation of Dynamics AX.

    This thesis project consists of an extensive literature study regarding both ERP Systems as well as other systems in regards to the cloud. It was decided early on to focus on the new version of Dynamics AX, which currently is only available in the cloud and compare this implementation to the two versions that the majority are using today, AX 2009 and AX 2012. The benefits of AX and Azure both being Microsoft products are clear with the welldesigned integrations and support all the way through the clients to the servers regarding backups and load balancing. It is shown how the developers have to work differently in regards to integrations with outside systems, especially in regards to AX 2009 with the frameworks having changed. The addition of Data Entities mean that the developers can save a lot of time by only needing a reference to the location of the object in the database instead of having to keep track of all the tables themselves.

    The analysis focuses on the differences in four different areas, performance & accessibility, scalability, cost savings as well as security & privacy. The background knowledge that is being used for the analysis primarily comes from the literature study as well as knowledge gained by studying the implementation at Scania today. The result shows that there are clear advantages regarding performance, cost savings and especially accessibility, however it is also clear that laws in a lot of countries still have not caught up with the fact that it is possible to use the cloud for data storage these days. Which in turn means that the best move in the near future for the majority of ERP users would be either a hybrid or private cloud within the borders of the same country.

  • 109.
    Carlsson, Henric
    Högskolan i Skövde, Institutionen för informationsteknologi.
    Using A Recommender To Influence Consumer Usage2013Independent thesis Advanced level (degree of Master (Two Years)), 30 poäng / 45 hpOppgave
    Abstract [en]

    In this dissertation, the issues of the increased awareness of energy use are considered. Energy technologies are continuously improved by energy retailers and academic researchers. The Smart Grid are soon customary as part of the energy domain. But in order to improve energy efficiency the change must come from the consumers. Consumers should be active decision makers in the Smart Grid domain and therefor a Recommender system suits the Smart Grid and enables customers. Customers will not use energy in the way energy retailers, and politicians advocates instead they will do what fits them. By investigating how a Recommender can be built in the Smart Grid we focus on parameters and information that supports the costumers and enables positive change. An investigation of what customers perceive as relevant is pursued as well as how relevancy can adjust the system. A conceptual model of how to build a Recommender is rendered through a literature review, a group interview and a questionnaire.

  • 110.
    Carlsson, Robin
    Linköpings universitet, Institutionen för systemteknik, Kommunikationssystem. Linköpings universitet, Tekniska högskolan.
    Investigation and Implementation of Coexistence Tool for Antennas2014Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    With the increase of the number of radios and antennas on today’s systems, the risk of co-site interference is very high. Intermodulation product and antenna coupling are two common sources of interference. The thesis investigates some features of a radio system, like antenna types, receiver parameters, intermodulation products and isolation, and suggests how this knowledge can be used to minimize the risk of co-site interference. The goal is to maximize the isolation between the antennas, by good frequency planning, the use of filters and taking great care in antenna placement. A first version of an analysis software was developed where transmitters and receivers can be paired and evaluated. An intermodulation product calculator was also implemented, to easily find which products are an issue and where they originate. The goal of the software is to be simple to use and easy to adapt to different setups and situations. It should also be easy to upgrade with new features.

  • 111.
    Carlsson, Stefan
    et al.
    KTH, Tidigare Institutioner, Teleinformatik.
    Halén, Erik
    KTH, Tidigare Institutioner, Teleinformatik.
    Mobile Internet: Content Adaptation for Limited Devices2000Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis investigates how to adapt content on the Web to the limited I/O capabilities of today’s WAP (Wireless Application Protocol) devices and how to translate from HTML to WML (Wireless Markup Language). We also give an overview of WAP and Mobile Internet and a brief analysis of the future of WAP.

    To evaluate different methods of adaptation, two existing Web sites are adapted to WML. Three different methods are tried and evaluated: The first method is a brute force WML re-coding of the site. The second method is an XML based solution that separates the data from the presentation and uses different XSLT (eXtensible Style sheet Language Transformations) style sheets for different devices. The third method uses a proxy that translates a requested page from HTML to WML. The proxy evaluated here is Oracle’s Portal-to-Go in its semi-automated form, i.e. where it is manually pre-configured for every site it adapts.

    An important issue is whether to adapt specifically for each device or whether to use generically written WML for the entire range of WAP devices. Another issue is that a WAP device only can receive a limited amount of information at a time, and this limit varies between different devices.

  • 112.
    Carlsson, Ulrika
    et al.
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för datavetenskap, fysik och matematik, DFM.
    Stenhammar, Marie
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för datavetenskap, fysik och matematik, DFM.
    Sociala medier: och kundinteraktion i mindre företag 2011Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Title: Social Media – And customer interaction in smaller firms

    Seminar date: 2011-06-10

    Course: Information Logistics, D-level.

    Authors: Marie Stenhammar and Ulrika Carlsson

    Advisor: Jaime Campos

    Key words: Social Media, Web 2.0, Co-creation, Viral marketing, Word of Mouth, smaller firms

    Purpose: This paper aims to describe the relevance of social media to smaller firms, the challenges and opportunities they face and what strategies they use, in the interaction with their customers.

    Methodology: The study is qualitative in nature and has an abductive approach. The empirical material consists of in-depth interviews with chosen companies and Internet observations.

    Theoretical perspectives: Social Media, Web 2.0, Co-creation, Viral marketing, Word of Mouth

    Empirical foundation: The study takes its empirical base from in-depth interviews with representatives from the small companies and internet observations connected to these.

    Conclusions: Smaller companies have great interest in social media. They preferably use Facebook, blogs, YouTube and Twitter. Their strategy is mainly to be very active and update their social media regularly. The opinion of the companies is that social media offer several possibilities such as stronger relationships with customers and the ability to collect information about the market.

  • 113.
    Carrara, Elisabetta
    KTH, Tidigare Institutioner, Teleinformatik.
    Wireless Adaptation of a Security Management Protocol Suite1999Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Internet Security is rapidly increasing in importance, as Internet itself is spreading out so fast. The IETF Security working group has defined the "IP Security Protocol Suite", a set of protocols that aim at securing the IP layer, so providing general security services for all kinds of applications.

    The IPSec Protocol Suite is completed by a protocol for key management and key exchange, the "Internet Security Association and Key Management Protocol (ISAKMP)" . It is currently an IETF Proposed Standard for the Internet.

    In this thesis we describe ISAKMP, and also its use together with the Internet Key Exchange (IKE) protocol, as a negotiation and key exchange protocol for IPSec. A general overview of cryptography is also provided, since ISAKMP widely uses modern cryptographic techniques.

    ISAKMP flexibility is at the cost of complexity and increased packet traffic. This should be faced in constrained communications, such as wireless. Therefore, this thesis introduces some proposals for a compressed version of the protocol, trying to reduce the number of handshakes and the number of transmitted bytes without significantly decreasing the security level.

    The model is based on the use of a Proxy, which follows the compressed version of ISAKMP on the side of the  mobile node, and then switches to the original version of the protocol on the wired side with the second peer. Ad-hoc solutions are adopted, and security implications are taken into account.

  • 114.
    Chabouni (nee Talbi), Sami
    KTH, Tidigare Institutioner, Teleinformatik. KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Investigation and Prototyping of a web based manager in a GSM SIM Application Platform1998Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The growing need for communication in the world has increased the use of telephony and has therefore led to several technical innovations and improvements in the field of telecommunications. As countries develop their infrastructure new ways of communicating arise. But the technical innovations do not completely guide the evolution of the infrastructure. Many times, the way people act, i.e., their mentality and traditions, decides how to invest in the infrastructure. As basic infrastructure is being built in some developing countries, others come up with new revolutionary solutions to replace old infrastructure and, for some developing countries the question arises whether to continue to invest several hundreds of millions of dollars in traditional telephony wiring. The cellular technique is revolutionary enough to be applied in countries that haven’t yet built a telephony network covering an adequate area of the country. In these countries, investments might therefore be focused on the cellular technique, rather than continuing to invest in cable networking. Thus adapting cellular technology to a worldwide distribution is necessary when it comes to administration and subscriber payment. The communication providers meet administrative obstacles when it comes to telephony services for a large-scale distribution. Will the subscribers pay for the services we offer them?

    Using Subscriber Identity Modules (SIM) one way to solve this problem is to define a prepaid scheme. It is based on the fact that the subscriber uses a unique identifier to make a connection and is billed using this identifier. The service provider is free to choose if the subscriber is thrustworthy or not and thus must pay in advance for the services or billed retroactively. This general way of solving administration problems does not apply only to developing countries where retroactive billing isn’t a common tradition. It is equally applicable to industrial countries where some people are banned from credibility for a couple of years because they haven’t paid their bills in time, or just because they don’t have employment at the time of their subscription application.

    To be in possession of a telephone is everyone’s right in most of the industrialized countries.

  • 115.
    Chairetakis, Eleftherios
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Alkudhir, Bassam
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Mystridis, Panagiotis
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Deployment of Low Interaction Honeypots in University Campus Network2013Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Large scale networks face daily thousands of network attacks. No matter the strength of the existing security defending mechanisms, these networks remain vulnerable, as new tools and techniques are being constantly developed by hackers. A new promising technology that lures the attackers in order to monitor their malicious activities and divulge their intentions is emerging with Virtual Honeypots. In the present thesis, we examine an extensive security mechanism based on three different open source low interaction honeypots. We implement this mechanism at our university campus network in an attempt to identify the potential threats and methods used against our network. The data gathered by our honeypots reveal valuable information regarding the types of attacks, the vulnerable network services within the network and the malicious activities launched by attackers.

  • 116. Chandu, Chiranjeevi
    Region of Interest Aware and Impairment Based Image Quality Assessment2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
  • 117.
    Chareonvisal, Tanakorn
    KTH, Skolan för elektro- och systemteknik (EES), Kommunikationsteori.
    ImplementingDistributed Storage System by Network Coding in Presence of Link Failure2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Nowadays increasing multimedia applications e.g., video and voice over IP, social networks and emails poses higher demands for sever storages and bandwidth in the networks. There is a concern that existing resource may not able to support higher demands and reliability. Network coding was introduced to improve distributed storage system. This thesis proposes the way to improve distributed storage system such as increase a chance to recover data in case there is a fail storage node or link fail in a network.

    In this thesis, we study the concept of network coding in distributed storage systems. We start our description from easy code which is replication coding then follow with higher complex code such as erasure coding. After that we implement these concepts in our test bed and measure performance by the probability of success in download and repair criteria. Moreover we compare success probability for reconstruction of original data between minimum storage regenerating (MSR) and minimum bandwidth regenerating (MBR) method. We also increase field size to increase probability of success. Finally, link failure was added in the test bed for measure reliability in a network. The results are analyzed and it shows that using maximum distance separable and increasing field size can improve the performance of a network. Moreover it also improves reliability of network in case there is a link failure in the repair process.

  • 118.
    Charvandeh, Jenny
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Location aware web access2009Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The user's mobile communication device has an increasing sense of where the user is. This location information may be very fine grained or very coarse. Given some amount of location information it is possible to create location aware services.

    This thesis presents and evaluates a system for location aware web browsing. Indoors the user can click on a point on a map (to establish a virtual location using a previously installed user application), outdoors the location can be provided by GPS, or the location might be provided by some other location system (indoors or outdoors), then each HTTP GET request for a URL will be augmented with information about the user's location or their virtual location. Subsequently a web query is created. Then the location information encoded as longitude and latitude is appended to this web query. The web server uses this location information to generate dynamically location aware web pages. Finally a web browser shows the web pages.

  • 119.
    Chatzaras, Anargyros
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Savvidis, Georgios
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Seamless speaker recognition2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In a technologically advanced society, the average person manages dozens of accounts for e-mail, social networks, e-banking, and other electronic services. As the number of these accounts increases, the need for automatic user identification becomes more essential. Biometrics have long been used to identify people and are the most common (if not the only) method to achieve this task.

    Over the past few years, smartphones have become frequently used gadgets.  These devices have built-in microphones and are commonly used by a single user or a small set of users, such as a couple or a family. This thesis uses a smartphone’s microphone to capture user’s speech and identify him/her. Existing speaker recognition systems typically prompt the user to provide long voice samples in order to provide accurate results. This results in a poor user experience and discourages users who do not have the patience to go through such a process.  The main idea behind the speaker recognition approach presented in this thesis is to provide a seamless user experience where the recording of the user’s voice takes place in the background.

    An Android application is developed which silently collects voices samples and performs speaker recognition without requiring extensive user interaction.  Two variants of the proposed tool have been developed and are described in depth in this thesis. The open source framework Recognito is used to perform the speaker recognition task. The analysis of Recognito showed that it is not capable of achieving high accuracy especially when the voice samples contain background noise. Finally, the comparison between the two architectures showed that they do not differ significantly in terms of performance.

  • 120.
    Chazalet, Boris
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Opportunistic Content Delivery utilizing Optimized Context Dissemination via the Service Interface in Ambient Networks2007Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    One of the novel and important features of Ambient Networks is the use of context information. Context in Ambient Networks concerns any information that describes the current situation of entities connected to the network (e.g. location, available connectivity and devices, etc.). Such context information can be used by applications, services, or network resources enabling them to automatically adapt their behavior without requiring user intervention. Thus, context in Ambient Networks provides a better user experience due to the auto-configuration, as well as auto-arrangement of service delivery and transport.

    This thesis presents an optimized version and implementation of the Distributed Context eXchange Protocol. This protocol is part of the context-aware architecture for Ambient Networks. The design and architecture of the Distributed Context eXchange Protocol (DCXP), utilizes a P2P overlay on top of UDP. This design and architecture have been revised to enable real-time context dissemination, while simultaneously removing bottlenecks. An analysis of this revised design including measurements in real-world scenarios, shows that DXCP offers a practical approach to context-sensing and dissemination, allowing rapid context changes and spontaneous use of new context sources as these become (un)available in dynamic rearrangements of network connectivity, facilitating the use of Ambient Network technologies. Finally, the thesis presents and demonstrates a novel use and the advantages of Optimized Context Dissemination as the Ambient Networks Service Interface (ASI) for Opportunistic Content Delivery. This is achieved by adding an (subset) API to the ASI which enables a Content Delivery Proxy to interface with DCXP and leverage context information to enable opportunistic content delivery across Ambient Networks.

  • 121.
    Chen, Chengshang
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Rear Approaching Vehicle Detection with Microphone2013Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    When a cyclist is cycling on a suburban road, it’s a problem to notice fast rear approaching vehicles in some cases. Looking back frequently is not a good idea. Finding some technical way to help cyclist perceiving rear approaching vehicles is quite necessary.

    This project aims to find some proper sensor to detect rear approaching vehicles. It’s separated into three steps. First, choose the suitable sensor and capture data. Then, find proper analyzing tool to analyze the capture data. Last but not least, draw a conclusion after analyzing contrast.

    Microphone is chosen as the sensor to recording the sounds form rear approaching vehicles. ”iRig Recorder FREE” is the program to transfer audio format. And the analyzing tool is to be Matlab. Matlab audio analysis makes good frequency spectrum for each piece of audio data. According to the frequency spectrum, the unique amplitude change around 1000 Hz is found when there is a rear approaching vehicle. This change is always distinct with or without noise.

    After getting the spectrum of different audio sources, the cross-correlation coefficient between 800 Hz and 1200 Hz is computed to see the correlation level. Then according to cross-correlation coefficient between new captured data and knowledge data, we can determine if there is a rear approaching vehicle in the new data or not.

    So, this project proves that the cross-correlation coefficient of frequency spectrum can determine if there is rear approaching vehicles or not. The future work would be automatic computer detect depending on this method.

  • 122.
    Chen, Lisan
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Schiller Shi, Tingting
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Targeted News in an Intranet2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In SharePoint 2013, Microsoft added a social networking function in the personal sites (My Site) of a user. In this version, a personal news feed has been added which shows events regarding subjects the user follows, such as document changes, user updates, tagged posts, and site activities. The purpose of the thesis is to investigate whether or not it is possible to extend the news feed function by adding an independent component as part of My Site, to allow users to follow corporate news by choosing their categories of interests.

    A prototype of the component was implemented and it met most of the objectives stated in the thesis. It is added to the default page of the user’s My Site as a web part and it is able to retrieve and display news that matches the user’s subscription. Although the web part still needs improvements in both functionality and design, it still confirms that it is possible to extend the current My Site news feed with such a component.

    Since the students working on this thesis had no prior knowledge of SharePoint or .NET development, the project brought new challenges, as the students needed to learn how to work in a SharePoint environment and to learn to use Microsoft Visual Studio for .NET development.

  • 123.
    Chen, Ta-wei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Optimization of Transport Security for Securing Peer-to-Peer Communication in Heterogeneous Networks2005Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis concerns the security of tomorrow’s peer-to-peer real-time communication in heterogeneous networks. Because of the additional delay caused by inband handshake and the poor compatibilities of some transport protocols, it was determined that existing security protocols such as transport layer security (TLS) and datagram transport layer security (DTLS) are not suitable in such a user scenario and a new security protocol should be designed. This new security protocol is called transport encapsulation security payload (TESP). TESP not only has the advantage of low initialization delay, but also fully supports transport protocols including TCP, UDP, stream control transmission protocol (SCTP), and datagram congestion control protocol (DCCP). Also a security analysis of TESP was carried out and no security flaws were found.

  • 124.
    Chen, Xu
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Performance Analysis of Wireless Multiplayer Games on Terraplay Systems2005Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis project was sponsored by Terraplay System AB. Terraplay System is a wireless online multiplayer game service provider in Europe. The purpose of this project was to provide a convenient and free latency test tool named Terraplay Test Toolkit (TTK) for game developers who utilize the Terraplay platform. Since wireless multiplayer games are latency sensitive, it’s necessary for game developers to estimate the real-time game latency before their development. TTK is based on Java Mobile Edition (J2me) technology, it can performs a real-time Round Trip Time (RTT) latency test. This project explored the application of the mobile development. Mobile development is a brand new field and becoming more and more popular. The design process and source code can be used as reference for mobile developers. Based on the Terraplay Test Toolkit, a series of experiments were conducted to test the ability of TTK. These experiments focused on end-to-end latency effects of wireless multiplayer games under different situations such as different packet size, different sending rates, high speed movement, and so on. Although TTK is not a professional test tool, it still reflects the latency variance under different conditions correctly. From these experiments, it was found that for the Terraplay enabled wireless multiplayer games, large average packet size (300 bytes) is NOT a factor with regard to the latency on the Terraplay System; the packet rate can affect the game latency. In a high speed-moving environment, game latency doesn’t obvious increase. Using HTTP can cause three times higher latency than simply using TCP. These conclusions are based on experimental results. These conclusions should guide wireless multiplayer game developers and game players.

  • 125.
    Cheng, Yuelong
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap.
    Ma, Xiaoying
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektronik, matematik och naturvetenskap.
    Cyclic Redundancy Check for Zigbee-Based Meeting Attendance Registration System2012Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    The research accomplished in this dissertation is focused on the design of effective solutions to the problem that error codes occur in the ZigBee-based meeting attendance registration system. In this work, several different check algorithms are compared, and the powerful error-detecting Cyclic Redundancy Check (CRC) algorithm is studied. In view of the features of the meeting attendance registration system, we implement the check module of CRC-8. This work also considers the data reliability. We assume use retransmission mechanism to ensure the validity and completeness of transmission data. Finally, the potential technical improvement and future work are presented.

  • 126.
    Cheng, Zhuo
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Hybrid Power Control in Time Division Scheduling Wideband Code Division Multiplex Access2011Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    With high date rates using Enhanced Uplink (EUL), a conventional signal to interference ratio (SIR) based power control algorithm may lead to a power rush due to self interference or incompatible SIR target [2]. Time division (TD) scheduling in Wideband Code Division Multiplex Access (WCDMA) is considered to be a key feature in achieving high user data rates. Unfortunately, power oscillation/peak is observed in time division multiplexing (TDM) at the transition between active and inactive transmission time intervals [1]. Therefore there is a need to revisit power control algorithms for different time division scheduling scenarios.

    The objective of power control in the context of this study is to minimize the required rise over thermal noise (RoT) for a given data rate, subject to the constraint that the physical layer control channel quality is sufficient (assuming that the dedicated physical control channel (DPCCH) SIR should not go below 3dB with a probability of at most 5%). Another goal is to minimize the local oscillation in power (power peaks) that may occur, for example due to transitions between active and inactive transmission time intervals.

    The considered hybrid power control schemes are: (1) non-parametric Generalized rake receiver SIR (GSIR) Inner Loop Power Control (ILPC) during active transmission time intervals + Received Signal Code Power (RSCP) ILPC during inactive transmission time intervals and (2) RSCP ILPC during active transmission time intervals + GSIR ILPC during inactive transmission time intervals. Both schemes are compared with pure GSIR and pure RSCP ILPC.

    Link level simulations with multiple users connected to a single cell show that:

    • The power peak problem is obviously observed in GSIR + GSIR transmit power control (TPC), but in general it performs well in all time division scenarios studied. GSIR outperforms other TPC methods in terms of RoT, especially in the TU channel model. This is because it is good in combating instantaneously changed fading and accurately estimates SIR. Among all TPC methods presented, GSIR + GSIR TPC is best in maintaining the quality of the DPCCH channel. No power rush is observed when using GSIR + GSIR TPC.
    • RSCP + RSCP eliminates the power peak problem and outperforms other TPC methods presented under the 3GPP Pedestrial A (pedA) 3km/h channel in terms of RoT. However, in general it is worse in maintaining the control channel’s quality than GSIR + GSIR TPC.
    • GSIR + RSCP ILPC eliminates the power peak problem and out-performs GSIR power control in the scenario of 2 and 4 TDM high data rate (HDR) UE and 2 TDM HDR UE coexistence with 4 Code DivisionMultiplex (CDM) LDR UE, in the pedA 3km/h channel, in terms of RoT. However, the control channel quality is not maintained as well during inactive transmission time intervals.
    • It is not recommended to use RSCP + GSIR TPC since it performs worst among these TPC methods for most of the cases in terms of RoT, even though it is the second best in maintaining the control channel quality. The power peak is visible when using RSCP + GSIR TPC.

    To maintain the control channel’s quality, a minimum SIR condition is always used on top of all proposed TPC methods. However, when there are several connected TDM HDR UEs in the cell, results indicates that it is challenging to meet the quality requirement on the control channels. So it may become necessary to limit the number of connected terminals in a cell in a time division scenario.

  • 127.
    Chengegowda, Venkatesh
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Analysis of Queues for Interactive Voice and Video Response Systems: Two Party Video Calls2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Video conversation on mobile devices is popularizing with the advent of 3G. The enhanced network capacity thus available enables transmission of video data over the internet. It has been forecasted by several VOIP service organizations that the present IVR systems will evolve into Voice and Video Response (IVVR) Systems. However, this evolution has many technical challenges on the way. Architectures to implement queuing systems for video data and standards for inter conversion of video data between the formats supported by calling parties are two of these challenges. This thesis is an analysis of queues and media transcoding for IVVRs.

    A major effort in this work involves constructing a prototype IVVR queuing system. The system is constructed by using an open source server named Asterisk and MySql database. Asterisk is a SIP based Public Exchange Server (PBX) and also a development environment for VOIP based IVRs. Functional scenarios for SIP session establishment and the corresponding session setup times for this queueing model are measured. The results indicate that the prototype serves as a sufficient model for a queue, although a significant delay is introduced for session establishment.  The work also includes analysis of integrating DiaStar™, is a SIP based media transcoding engine to this queue. However, this system is not complete to function with DiaStar for media translation. The study concludes with a mention of the areas for future work on this particular system and the general state of IVVR queuing systems in the industry.

  • 128.
    Cho, Ming-King
    KTH, Tidigare Institutioner, Teleinformatik.
    Paving the Information Superhighway at SNRA: A Proposal for Multimedia Traffic Information Systems1995Independent thesis Advanced level (degree of Master (Two Years)), 12 poäng / 18 hpOppgave
  • 129.
    Cholaraju Narasaraju, Vignesh
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Impact of Extended DRX Cycles on Battery Lifetimes and UE Reachability2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Several UE energy consumption optimization techniques have been proposed for Machine Type Communication (MTC) devices. Extended Discontinuous Reception (eDRX) in idle mode is one such technique wherein an UE in idle mode wakes up only during its Paging Occasion (PO) to monitor paging messages from eNodeB (eNB). The PO is located within a Paging frame (PF). The PF is a function of System Frame Number (SFN) cycle of eNB. The paging messages may be sent asynchronously from multiple eNBs to a UE. Due to asynchronous operation of eNBs, SFN takes on different values at a given point in time and therefore a paging message is transmitted at different points in time from different eNBs. Due to this SFN misalignment between eNBs, an idle mode UE might receive and respond to the same paging message from different eNBs and/or miss a PO and thus the paging message. Due to this spread in time of SFN and PO, the actual handling of paging message by the UE becomes inefficient leading to increased UE energy consumption and decreased reachability. These issues, resulting from paging handling, will get amplified further if DRX period is extended longer (eDRX).

    In this study, we investigate the impact of eDRX cycles and mobility related parameters such as UE speed, cell size and size of SFN misalignment between eNBs on UE energy consumption, use of network resources and UE reachability. Receiving and responding to the same paging message results in increased energy consumption for UE and increased signaling between UE and the network. Missing a PO results in delayed paging reception and hence decreases UE reachability. As the DRX cycle lengths are increased from existing maximum of 2.56 seconds to 10.24 seconds and beyond, we see a reduction in UE energy consumption by more than 90%, but the network signaling and the delay to reach the UE increases linearly as a function of the DRX cycle length. We observe that the number of duplicate paging message receptions/missed POs is minuscule for DRX cycle lengths below 10.24 sec. At DRX cycle length of 10.24 seconds, UEs travelling across 500 m cell radius at speeds of 3, 50, 100 km/h the percentage of duplicate paging receptions are 0.07, 0.11, and 0.15 respectively. This duplicate paging message reception increases the UE energy consumption by 2.31, 6.15 and 12 percent of the total energy units respectively. Similarly, UE misses nearly 0.34, 0.39, and 0.405 percent of the total POs respectively. Depending on the number of consecutive PO misses, the UE reachability decreases. But by reducing the size of SFN misalignment between eNBs, we see that it’s possible to increase the reachability for UEs in eDRX. Further we have proposed solutions based on our analytical study to avoid duplicate paging message reception by UE, increase UE reachability and also reduce UE energy consumption using a windowing technique. We conclude that when a UE is configured with eDRX cycles, the tradeoff between battery lifetimes and UE reachability is based on mobility characteristics and service requirements.

  • 130.
    Choudrey, Sajaval
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Hiltunen, Kim
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Moln för Försvarsmakten2015Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    An organization with such a big responsibility as the Swedish armed forces constantly needs to find new ways to develop and increase their effectiveness when it comes to management, administration and organization. An information system with cloud computing as a basis would mean a modernization of the Swedish armed force’s administration and could potentially live up to the security standards within the organization. The primary goal of the thesis is to present and analyze cloud solutions that the Swedish armed forces eventually could integrate in to their activities. The first part of the thesis gives an introduction to the cloud technology with the security aspects of a cloud as a large part of the focus. This is followed by information about the Swedish armed forces and their current IT-systems, as well as information on the requirements they have for the implementation of new IT-systems within the organization. Two different cloud services from VMware and Cloudstack have been examined in order to see whether these could be used for a future implementation. The focus of the analysis lies heavily on the security issues and questions, that arise, for each solution, as the security aspect is something that is very important for the Swedish armed forces.

    The thesis also touches on the economical benefits and economical difficulties associated with cloud service implementation. The purpose of this is to see whether an eventual implementation is beneficial or not.

  • 131.
    Chrast, Lukas
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Knaperek, Jozef
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Kovalcik, Marek
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    BANDWIDTH AGGREGATION OF MOBILE BROADBAND LINKS ON RASPBERRY PI BASED ACCESS POINT2014Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    This thesis is concerned with the usability of Raspberry Pi as the access point in the mobilebroadband network environment. The first part of the thesis is dedicated to Raspberry Pi itself;hardware required to set up WLAN and WAN; and to the analysis of suitable solutions forbandwidth aggregation, particularly the load balancing of mobile broadband connections andtheir aggregation into one logical link. The second part deals with the implementation of thesesolutions and subsequently with their testing and verification. The evaluation of results gives aninteresting outcome. Load balancing has proven to be resilient and feasible solution forbandwidth aggregation in the mobile broadband network environment where the speed, packetloss and jitter are of main concern. The second scenario, where the connections are bundled intoone logical link, has turned out to give variable results. Its performance is susceptible to thechanges in the mobile broadband network as the packets across the links in the bundle alternatein the round-robin fashion.

  • 132.
    Christensson, Anja
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Gerson, Nadine
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Wallin, Edit
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    A Mapping of Scandinavian Smart Grid Development in the Distribution System from an ICT perspective2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
  • 133.
    Christiansson, Fredrik
    KTH, Tidigare Institutioner, Teleinformatik.
    A distributed, mobile positioning systemfor wireless, handheld devices2000Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis investigates the possibilities of implementing a location awareness mechanism for the so-called lesswire localNavigator. The author claims that it is possible to implement such a mechanism within the given prerequisites and constraints, even though with today’s technology it may not be economically feasible.

    Due to the lesswire’s constraints: high accuracy (67%), high-resolution (12 m2) and no hardware modification allowed to the mobile device, the suggested scheme uses Time Difference Of Arrival technology (TDOA). The main advantage of TDOA, as stated in this thesis, is the fact that it is almost totally independent of the preferred wireless technology of the mobile device. TDOA technology therefore, can be applied to a wide range of wireless networks (primarily TDMA, CDMA, FDMA – based). A disadvantage of this scheme is the fact that the network infrastructure needs to be extremely well synchronized - which in turn implies higher costs.

    Depending on how the synchronization problem is solved, the proposed system may well be economically feasible in the near future.

  • 134.
    Chuasomboon, Sasit
    Linköpings universitet, Institutionen för systemteknik, Kommunikationssystem. Linköpings universitet, Tekniska högskolan.
    A comparison of ranging and localization techniques in indoor, urban, and tunnel environments2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Localization in wireless network sensors is an attractive research area nowadays. It is widely used in many applications e.g., indoor/outdoor asset tracking, intrusion detection, search-and-rescue, road traffic monitoring, and water quality monitoring. An accuracy and robustness to noise are important issues for localization which is needed to study and research to find the best solution. This thesis compares a ranging and localization techniques in indoor, urban and tunnel through a high performance ray-tracing simulator, Wireless InSiteR . Ranging techniques are based on two standard distance related measurement schemes e.g., RSS and TOA. A linearized least squares technique with reference node selection approach is chosen to estimate unknown nodes positions. Indoor and urban area are built-in floor plan and terrain available in simulator program, while tunnel is designed. In general, localization accuracy suffers from multipath and NLOS condition. This thesis also observes characteristic of them from ray-tracing method perspective. Firstly, important simulation parameters such as number ofreflections/diffractions, types of waveform, and types of antenna are analyzed oneach environments. Then, the models for distance estimation based on RSS and TOA measurements are created using measurements in simulated environments. The thesis proposes four scenarios for distance estimation model. They are line-of-sight (LOS), non-line-of-sight (NLOS), combination of LOS and NLOS, and NLOS with obstacle. All four scenarios models are derived along with model error distribution to observe characteristic of noise due to multipath and NLOS condition. Finally, the localization using only LOS condition measurements, is tested on each environment and compared results in term of accuracy.

  • 135.
    Cordella, Marco
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    User-to-Network Interface in Optical Network2002Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This masters thesis work was carried out at the Optical Network Research Laboratory Ericsson Telecom AB in Kungens Kurva (Sweden). Its primary objective is to study the O-UNI (Optical User-to-Network Interface), a service control interface between client devices (e.g., IP routers and ATM switches) and the transport network, and the different signaling protocols running over it.

    This thesis was conducted for the Institute for Microelectronics and Information Technology (IMIT) at the Royal Institute of Technology (KTH) in Stockholm (Sweden) and for the Department of Telecommunications at Politecnico di Torino in Turin (Italy).

    Recently, the Internet Engineering Task Force (IETF), the Optical Internetworking Forum (OIF) and the International Telecommunication Union (ITU) have all started working on standards for routing and signaling protocols for the Optical Transport Network (OTN). While these efforts aim to create a set of protocols to act as the interface to an optical core, the emerging architectures are different enough to present difficult choices for vendors and service providers. The goal of this thesis work was to analyze the state of the art of the OIF based UNI (User-to-Network Interface) in order to gain competence in the area and study this UNI model by implementing some of the abstract messages defined in the UNI 1.0. In particular, the UNI signaling protocols, adapted from the GMPLS RSVP-TE (Generalized Multi-Protocol Label Switching) (Resource Reservation Protocol - Traffic Engineering) and LMP (Link Management Protocol) specifications were implemented.

  • 136.
    Coyet, Peter
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Mobil Positionering med Kartstöd2003Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This master thesis was conducted on behalf of SL Infrateknik AB. The goal of the master thesis was to examine the possibilities for SL to create a mobile positioning service with map support for their travellers. The result would give SL a basis for making decisions relating to the development of such a service.

    The studies have focused on different techniques of positioning and the existing operators in the Swedish market that provide positioning. To acquire understanding of services with map support, the construction and usage of geographic information systems have been examined. These studies have also involved the use of geographic information systems for map presentation on mobile units.

    Since SL’s traffic covers the whole county of Stockholm, it was important to study how SL can reach as many travellers as possible with the new service. However, the accuracy of mobile positioning varies significantly depending on the geographic location. Measurements showed that the accuracy outside Stockholm’s city centre is poor. With 3G, the accuracy is expected to be a bit better. The current conditions are therefore not suitable for creating a positioning service with acceptable accuracy for the whole county of Stockholm.

    The conclusion is that SL should not invest in a mobile positioning service at present. This conclusion is mainly based on such factors as accuracy, choice of operator and communication performance.

  • 137.
    Crespo Ramírez, Daniel
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Smartphone traffic patterns2011Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The growing popularity of new generation mobile terminals, known as „smartphones‟,has increased the variety and number of such devices. These devices make use of the resources offered by Universal Mobile Telecommunication Services (UMTS) networks toaccess on-line services such as web browsing, e-mail, audio and video streaming, etc. UMTS networks have to deal with an increasing amount of data traffic generated by smartphones. Because of the fact that the smartphone is battery powered and is trying to satisfy the needs ofboth applications and human users there is a need to be smarter about how to manage both network and terminal resources.

    This thesis explores the possibility of making a better use of the network and terminal resources by exploiting correlations in the events of the smartphone-generated traffic. We propose a mechanism, through which the network can predict if a terminal is going to produce data transmission or reception in a near future, based on past events in its traffic. According to this prediction, the network will be able to decide if it keeps or releases the resources allocated to the terminal. We analyze the benefits from the network and the terminal point ofview. We also describe a method to estimate an upper bound of the time until the next transmission or reception of data in a near future.

    We show that it is possible a reduction of the time that each terminal wastes in its maximum power consumption state, but this reduction implies a penalty in the transmission/reception throughput of the terminal. The reduction is not uniform for all terminals: terminals whose traffic presents a predictable behavior gain the most. Estimates of upper bounds of time until the next transmission or reception are more accurate if they are made taking as input information about interarrival times of previous packets.

  • 138.
    Dabbous, Fouad
    KTH, Tidigare Institutioner, Teleinformatik.
    The mobitex network in the point of sale application1995Independent thesis Advanced level (degree of Master (Two Years)), 12 poäng / 18 hpOppgave
    Abstract [en]

    The Purpose of the work is to provide a solution for interfacing the point-of-sale terminal (POST) with Mobitex radio modem (mobidem) on the mobile side and a solution for interfacing the authorization center host computer with the Mobitex area exchanges (MOX), at the fixed side. The application of POS was coded to use the Mobitex network as a communication link between the POST and the host computer.

    An existing POS application was used during the simulation where the communication procedure had been rewritten to meet the Mobitex network communication specifications. Analyses and ideas related to the suggested communication model and procedure were discussed during the simulation phase.

  • 139.
    Dadash Pour Khalkhali, Mohammad Mehdi
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för informations- och kommunikationssystem.
    User Experience Enhancement in 3D Video Conferencing2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    3D video conferencing is continuously evolving to make the visual experience realistic. The main advantage of 3D video conferencing deals with the addition of depth perception which enhances the user experience. The configuration of capturing and rendering equipments and the location of scene objects play an essential role in the quality of the user experience. An incorrect configuration of equipment parameters or an inconsistent distribution of scene components could cause an uncomfortable user experience, yielding in user sickness and dizziness.

    The aim of this thesis is therefore to provide the tools and methods to assure a comfortable user experience when using Ericsson’s stereoscopic 3D video conferencing system. To achieve this goal, an investigation on the capturing and rendering systems has been performed to identify possible conflicts. This investigation has shown that accommodation-convergence rivalry, comfortable viewing range and stereo framing violation are the major sources of user discomfort in 3D video conferencing.

    An algorithm for continuous analysis of produced stereoscopic content has been proposed. In particular, it detects wrong equipment configuration and problematic content in real time by means of automatic adjustments or user interaction, either at initiation phase or during the call session at capturing side. To validate and evaluate the efficiency of the implemented solution, a subjective test with participation of the 3D experts has been carried out. It has been shown that the proposed solution can detect targeted problems with high accuracy and apply corrective actions. It is important to note that manual solutions are not immune to problems. Nevertheless, it has also been shown that automatic solutions can considerably compensate manual methods inconsistency and provide a comfortable user experience. 

  • 140.
    Dahlberg, Axel
    et al.
    KTH, Skolan för teknik och hälsa (STH), Data- och elektroteknik.
    Francén, Jonas
    KTH, Skolan för teknik och hälsa (STH), Data- och elektroteknik.
    IPv6-adresshantering och prefixdelegering i MPLS VPN-nät2013Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    För full migrering till IPv6 behöver utbudet av datakommuniktionsstjänster anpassas för den nyagenerationens IP-protokoll med bevarad eller utökad funktionalitet. Detta examensarbetes mål äratt ta fram en eller flera lösningar som möter krav och tekniska förutsättningar för att utöka företagetDGC:s tjänst IP-VPN för IPv6. Detta innefattar adresstilldelningstekniker som prefixdelegeringoch automatisk adresskonfigurering i befintlig nätinfrastruktur.Lösningarna presenteras i sex framtagna scenarier som har undersökts utifrån tester, analys ocherfarna problem som uppstått. Undersökningen formade kriterierna skalbarhet, konfigurationenskomplexitet, kompatibilitet, RFC-stöd och krav från DGC som tas hänsyn till i utvärderingen avden bäst lämpade lösningen.Utvärderingen har gett ett resultat i form av ett rekommenderat scenario som är implementerbartenligt uppsatta mål.Tekniker som skulle kunna påverka valet av bäst lämpade lösning, men som inte är tillgängliga,diskuteras och presenteras för att poängtera vad som kan behövas tas i beaktande för framtiden.

  • 141.
    Dalarsson, Stefan
    KTH, Skolan för informations- och kommunikationsteknik (ICT). Department of Mathematics.
    ANALYTICAL AND NUMERICAL STUDY OF HELICAL ANTENNAS IN RADIO DEVICES USING INTEGRAL EQUATIONS2015Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
  • 142.
    Damola, Ayodele
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Peer to peer networking in Ethernet broadband access networks2005Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The use of peer-to-peer (P2P) applications is growing dramatically, particularly for sharing content such as video, audio, and software. The traffic generated by these applications represents a large proportion of Internet traffic. For the broadband access network providers P2P traffic presents several problems.

    This thesis identifies the performance and business issues that P2P traffic has on broadband access networks employing the McCircuit separation technique. A mechanism for managing P2P within the access network is proposed. The P2P diversion algorithm aims to manage P2P traffic within the access network based on layer 2 and layer 3 information without employing intrusive layer 7 traffic detection. To solve the contention problem experienced by best effort traffic in the access network, a solution based on the diversion algorithm and on a QoS based traffic classification scheme is proposed. A business model defining the business roles and pricing schemes is presented based on the features offered by the P2P diversion algorithm introducing new opportunities for gaining revenue from P2P traffic for the network service providers and providing better services to users.

  • 143.
    Dandugula, Chaitanya
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Networking for Smart Meters2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    "Smart grid" generally refers to a class of technology bringing electricity delivery systems into the 21st century, using computer-based remote control and automation. With the growing energy demand, efficient usage of the available energy resources is increasingly becoming a major issue around the world. Smart grid is a step in that direction. Research in the European Union and the United States are currently underway to modernize the existing and aging transmission grid and to streamline the usage of electricity.

    A typical electricity grid consists of two major entities - the utility company and the distribution control system (DCS). Electricity is generated at the utility company and the DCS is responsible for the distribution of electricity to individual homes/consumers. A smart meter (SM) is an electronic device that measures the electricity consumed at the consumer's premises and provides added information to the utility company. The data concentration unit (DCU) is a device acting as a communication hub collecting and encoding data from multiple smart meters in a neighborhood and forwarding the data to the utility company. The aim of this project is to design a network for securing the communication between the SM and the DCU in a smart metering network environment.

    The meter data communicated from the SM to the DCU is very sensitive and in the hands of an attacker, can reveal significant personal information about an individual. Hence it is of at most importance to protect the meter data transmitted from the SM. On the other hand the control signals transmitted from the DCU to the SM, need protection in order to thwart off unauthorized signals (i.e., an intruder can impersonate the DC and send out control signals to the SMs). Hence the SM and the DCU should be authenticated by each other and authorized and the data and/or control signals exchanged between them should be encrypted.

  • 144.
    Daniulaityte, Neringa
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för informatik (IK).
    ICT tools usage in Virtual teams: Analysis of the correlation between the ICT Toolscapabilities & Virtual teams challenges.2017Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    This quantitative research study focuses on the capabilities of ICT tools used by virtualteams and seeks to find out what, if any, correlation between the ICT tools capabilitiesand challenges that virtual teams face exist. The study addresses four prominent virtualteam challenges: forming trust and relationships, information overload, communicationbreakdown, lack of team synergy and cohesion. It analyses ICT tools and establishhypothesis using MST theory and the existing research in this field. The data analysis isconducted using Spearman’s Rho correlation. The findings show that the correlationbetween ICT tools usage and the challenges that virtual teams face are not statisticallysignificant to establish a link between virtual team challenges and ICT tools usage. Thiscould mean that a significantly larger sample is required to establish the link betweenthese two variables. It could also mean that the virtual team challenges need to be reevaluatedas the collected data suggests that the discussed challenges are rarelyexperienced by virtual teams. Therefore, further studies are needed in order to establishthe correlation between the virtual team challenges and ICT tools usage.

  • 145.
    Dannerud, Sara
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Sårbarheter i routrar och switchar2008Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Det finns många olika källor där man kan få information om sårbarheter i routrar och switchar. Mängden information gör det dock svårt att på ett enkelt sätt ta reda på vilka tillverkare som drabbas och vilken typ av sårbarheter man hittar i nätverksutrustning. Därmed är det också svårt att veta hur man ska skydda sin utrustning mot attacker.

    I detta examensarbete analyseras ett antal befintliga sårbarheter i routrar och switchar. Dessa sårbarheter har valts ut genom att i National Vulnerability Database söka på orden ”router” och ”switch”. Målet med analysen är att svara på frågorna vem, vad och varför när det gäller sårbarheter i routrar och switchar.

    Examensarbetet beskriver vilka tillverkare som drabbas av sårbarheter, vilka typer av sårbarheter som är vanligast i routrar och switchar och varför sårbarheterna har uppstått. Utifrån detta dras slutsatser om vad man som användare ska göra för att undvika attacker mot sin utrustning. I arbetet beskrivs också hur tillverkarna väljer att hantera de sårbarheter som finns i deras produkter.

  • 146.
    Darwis, Darwis
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Implementation and Analysis of VoIP CPE Management System using TR-0692008Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Customer Premises Equipment (CPE) management is underestimated by the CPE vendors and services providers while it is in fact one of the most important aspects to ensure the high quality of service. Many people still think CPE management is the same as network management. Thus, they use the Simple Network Management Protocol (SNMP) to manage their CPEs. However, SNMP alone was thought not to scale nor to support the provisioning of the types of services which internet services providers must support today.

    This thesis highlights the importance of CPE management, how it is implemented using the TR-069; a CPE management protocol defined by the DSL Forum, and how a management system can be used for VoIP service management, and whether a CPE should implement TR-069 or SNMP as the management system to support. In the addition, the TR-069 will be compared against the SNMP to determine which one is more suitable for CPE management. An interesting conclusion is that while TR-069 does have some advantages over SNMP for managing services rather than simply managing the device, these advantages are not a large as initially believed nor has TR-069 avoided the problem of proprietary management information which SNMP has demonstrated.

  • 147.
    Dautbegovic, Dino
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för datavetenskap, fysik och matematik, DFM.
    Chirp Sounding and HF Application: SDR Technology Implementation2012Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    From a HF propagation point of view, the ionospheric layers act as partially conducting media (plasma) in which a transmitted radio wave can reflect upon.A way of determining whether a radio wave with a given frequency will reflect from the ionosphere or completely penetrate is to utilize special radar instruments know as ionosondes or chirp sounders. The technique is widely used by amateur enthusiasts and military radio users for monitoring available radio channel links between two remote locations and can often serve as a base for HF radio prognoses.The objective of this Bachelor’s Thesis was to explore, implement and test a single channel receiver for monitoring ionospheric sounders. The implementation is based on Software Defined Radio (SDR) technology and relies on the GNU Chirp Sounder (gcs) open source script program.

  • 148.
    Derakhshanno, Homayoun
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Voice over IP over GPRS2008Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The Voice over IP (VoIP) technology has become prevalent today due to its lower cost than traditional telephony and its ability to support new value-added services. Additionally, the increasing availability of wireless internet access has led to research studies examining the combination of wireless network access with voice over IP. With the widespread availability of advanced mobile phones and Pocket PCs, the need for VoIP applications on these mobile platforms is tangible. To enable this, we need to evaluate the current wireless access technologies to see if they can support the necessary traffic and implement software to offer these VoIP services to users.

    In order to easily implement an IP-based service on GSM technology, we should use the GPRS service provided by the GSM operators. In this thesis, we evaluate Voice over IP service over GPRS in terms of feasibility and quality. Following this we ported a locally developed VoIP program to a Pocket PC (with GSM SIM-card support) which runs Microsoft’s Windows Mobile in order to provide suitable software as needed to offer the service from such a portable device.

  • 149.
    Derenius, Fredrik
    Högskolan i Skövde, Institutionen för kommunikation och information.
    Framställandet av en säker LiveCD för distansarbetare: Ett projekt baserat på öppen källkod2012Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Studien ämnar undersöka hur en LiveCD kan stödja en säkrare datormiljö för distansarbetarepå ett enkelt sätt. Distansarbetare arbetar utanför arbetsplatsens säkrare datormiljö vilket gördem till en mer utsatt grupp av datoranvändare. Många av dagens datoranvändare tyckerdessutom säkerhet relaterat till datorer och nätverk är komplicerat. Implementerad lösningtillhandahåller därför möjligheten att med hjälp av en LiveCD och ett USB-minne få tillgångtill både en säker fjärranslutning och fjärrskrivbord, genom att enbart skriva in ett lösenord.Tjänsterna konfigureras alltså automatiskt i bakgrunden; användaren behöver inte hålla redapå mer än ett lösenord. En LiveCD är också ett skrivskyddat medium vilket innebär attskadlig kod har svårt att få fäste i systemet. Resultatet är att distansarbetare med olika behovoch kunskapsnivå gällande dator- och nätverksäkerhet erbjuds möjligheten till en säkraredatormiljö på ett enkelt sätt.

  • 150.
    Deshayes, Dan
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Sjöfartshögskolan (SJÖ).
    Sedvallsson, Simon
    Linnéuniversitetet, Fakulteten för teknik (FTK), Sjöfartshögskolan (SJÖ).
    Nätverksoptimering med öppen källkod: En studie om nätverksoptimering för sjöfarten2015Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Detta examensarbete handlar om hur datatrafik över en satellitlänk kan optimeras för att minska laddningstider och överförd datamängd. Syftet med studien är att undersöka i vilken omfattning datatrafik mellan fartyg och land via satellitlänk kan styras så att trafiken blir effektivare. Genom att använda DNS-mellanlagring, mellanlagring av webbsidor samt annonsblockering med pfSense som plattform har examensarbetet utfört experiment emot olika hemsidor och mätt laddningstid samt överförd datamängd. Resultatet visade att det fanns stora möjligheter att optimera nätverkstrafiken och de uppmätta resultaten visade på en minskning av datamängden med 94% och laddningstiderna med 67%.

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