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  • 151.
    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
  • 152.
    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.

  • 153.
    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.

  • 154.
    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.

  • 155.
    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.

  • 156.
    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.

  • 157.
    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.

  • 158.
    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.

  • 159.
    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.

  • 160.
    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%.

  • 161.
    Dhainaut, Guillaume
    KTH, Skolan för elektro- och systemteknik (EES), Kommunikationsnät.
    A reverse proxy for VoIP: Or how to improve security in a ToIP network2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The need for security is crucial in Telephony over IP (ToIP). Secure protocols have been designed as well as specific devices to fulfill that need. This master thesis examines one of such devices called Session Border Controller (SBC), which can be compared to reverse proxies for ToIP. The idea is to apply message filters to increase security.

    This thesis presents the reasons of SBC existence, based on the security weaknesse sa ToIP network can show. These reasons are then used to establish a list of features which can be expected from a SBC and discuss its ideal placement in a ToIP network architecture. A test methodology for SBCs is established and used on the free software Kamailio as an illustration. Following this test, improvements of this software, regarding threats prevention and attacks detection, are presented and implemented.

  • 162.
    Di, Shuang
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    USB Attached Network Performance: Uplink Performance2009Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    More and more people all over the world are using a USB modem to connect to the Internet. This is especially true in Sweden- which has the highest 3G coverage in Europe. Comparable to fixed broadband access, using a 3G USB modem is a wonderful experience for the customer. Increasingly, anywhere we can use our cellular phone is a place that we are able to access the Internet, even if we are traveling in a train, walking in a park, or sitting on the beach. This makes working on the move much easier. However, customers do not know if the network throughput, delay, and the cost of connectivity match their needs. Additionally, there is also the question of the time to connect to the network when there has not been some traffic for a period of time. However, the throughput, delay, and "time to connect" when using such a modem to connect to a wireless network depend on several factors. In this thesis we will examine these factors. More specifically, the thesis will analyze in detail the effects of using a USB attached network interface, in order to gain greater understanding of such an interface’s network performance. We have chosen to focus on the uplink, as it was expected to have a low throughput and it has not had as much attention as the downlink performance.

  • 163.
    Dimitriou, Eleftherios
    KTH, Tidigare Institutioner, Teleinformatik.
    An Archive Robot for Video Mail1998Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Today most of the real-time voice communications are carried over the Plain Old Telephone System (POTS). In the future that might well change. Research indicates a strong interest for developing the network to support real-time communications in a satisfactory way. Applications will be needed in this new world of IP (Internet Protocol) based communications.

    In this thesis we present an application called the Video Mail service. The Video Mail service can record and playback audio and video messages over the Internet using standard Internet telephony protocols. It is built on top of a more general platform called the Archive Robot. The Archive Robot provides the real-time functionality of the system. It is not explicitly designed to support the Video Mail service. Other services such as Conference Tool and Interactive Voice Response can also be supported.

    The Video Mail service was designed and implemented. Furthermore, this first prototype was used to evaluate the performance of the overall system.

  • 164.
    Dominique, Torkel
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Push services based on SIP2001Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The Session Initiation Protocol (SIP) is the most potential protocol for Real Time IP communication, for example IP telephony, today. This M.Sc. thesis project aim to create a solution for information providers to push information to a large numbers of users, using the SIP protocol and a number of proposed extensions to SIP. The system will be built on a SUBSCRIBE/NOTIFY mechanism similar to the one used for instant messages and presence. This system can be used for companies to build information push services (i.e. News, Traffic information, etc.) or to push commercial advertisement.

    The reason to use the SIP protocol for this is that SIP has already solved the addressing problem by introducing email-like addresses that follow the user when he moves around in the system. This is perfect for the push service that wants to reach the user wherever he is.

  • 165.
    Domínguez Sánchez, Carlos
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Speaker Recognition in a handheld computer2010Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Handheld computers are widely used, be it a mobile phone, personal digital assistant (PDA), or a media player. Although these devices are personal, often a small set of persons can use a given device, for example a group of friends or a family.

    The most natural way to communicate for most humans is through speech. Therefore a natural way for these devices to know who is using them is for the device to listen to the user’s speech, i.e., to recognize the speaker based upon their speech.

    This project exploits the microphone built into most of these devices and asks whether it is possible to develop an effective speaker recognition system which can operate within the limited resources of these devices (as compared to a desktop PC). The goal of this speaker recognition is to distinguish between the small set of people that could share a handheld device and those outside of this small set. Therefore the criteria is that the device should work for any of the members of this small set and not work for anyone outside of this small set. Furthermore, within this small set the device should recognize which specific person within this small group is using it.

    An application for a Windows Mobile PDA has been developed using C++. This application and its underlying theoretical concepts, as well as parts of the code and the results obtained (in terms of accuracy rate and performance) are presented in this thesis. The experiments conducted within this research indicate that it is feasible to recognize the user based upon their speech is within a small group and further more to identify which member of the group is the user. This has great potential for automatically configuring devices within a home or office environment for the specific user. Potentially all a user needs to do is speak within hearing range of the device to identify themselves to the device. The device in turn can configure itself for this user. 

  • 166.
    Drugge, Fredrik
    KTH, Tidigare Institutioner, Teleinformatik.
    Design of a Multimedia Help System in UNIX1995Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The department G at EUA has developed a project management method and tool, PROPS-N. The PROPS-N is an on-line system built in FrameMaker that operates in a SUN/UNIX environment.

    This master's thesis attends to the problem of how to organize and implement a prototype of a multimedia help system for PROPS-N, with the help of the commercial tools available today.

    I have searched for multimedia authoring tools and screen activity recorders, that can be used for the development of the prototype. I have evaluated the multimedia authoring tools IconAuthor 6.0, Gain Momentum 3.1 and MetaCard 1.4. I have also evaluated the screen activity recorders ScreenPlay 2.3 and XRecorder 1.101.

    Some aspects that help you create usable help systems, and ensure learning, are also shown in this thesis. I have used a Multimedia Design and Development Methodology, with the tools ScreenPlay and MetaCard for the implementation of the prototype.

    This thesis also includes suggestions for future development of the prototype.

  • 167.
    Du, Manxing
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Analyzing Caching Gain in Small Geographical Areas in IP Access Networks2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Since its emergence, user generated content (UGC) has become the driving force in the growth of Internet traffic. As one of the most successful and popular UGC systems, YouTube contributes a great share of Internet traffic volume and has attracted a lot of academic interest. The continuously increasing amount of IP traffic motivates the need for better network design, more efficient content distribution mechanisms, and more sustainable system development. Web caching is one of the widely used techniques to reduce the inter Internet Service Provider (ISP) traffic. Web caching is considered an important part in the design of a content distribution infrastructure.

    This master’s thesis utilizes a one month trace of YouTube traffic in two residential networks in Sweden. Based upon a systematic and in-depth measurement we focus on analyzing the geographic locality of traffic patterns within small areas for these two networks. We summarize the YouTube traffic characteristics and user replay patterns, and then discuss why caching can be useful for YouTube-like systems.

    We present the optimal caching gain on a per area basis and also divide users into two groups: PC and mobile device users to show the caching gain for these two groups. Overall, an infinite capacity proxy cache for each small area could reduce the YouTube streaming data traffic by 30% to 45%. The result presented in this paper help us to understand YouTube traffic and user behaviors and provides valuable information for the ISPs to enable them to design more efficient caching mechanisms.

    When this work began we thought that a reduction of backhaul traffic (especially for mobile operators) may delay the need to make investments in upgrading their network capacity. However, an important conclusion from this thesis project is that the cache efficiency depends on the terminal type. For mobile terminals (smart phones, iPads, etc) a terminal cache solution is found to be the most efficient. For PCs in fixed networks, a network cache would be more efficient. It should be noted that the mobile terminals covered in the project are connected through home Wi-Fi, so further research is needed in order to draw definite conclusions for caching solutions for cellular networks.

  • 168.
    Du, Tianlong
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Ye, Jie
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    CHAT: City Error Handling through Instagram and FixaMinGata2013Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Deficient public infrastructure always causes significant complications to citizens’ daily travelling. However, it is hard for authorities to discover all the problems that suddenly occur on the road. To address these issues, one direction is to develop a system that allows citizens to report a problem quickly, so that the authorities could receive the information timely and solve it as soon as possible.

    In our project, instead of developing everything from scratch, we have decided to use Instagram and FixaMinGata as components. Instagram is a smart phone application that is used to share a photo with public. We use it to make a report which related to potholes, broke street lights and other similar problems.  FixaMinGata is a Swedish website that allows people to publish infrastructure problem reports online and forwards them to the authorities.

    Thus, the main purpose of our project is to make an interface between Instagram and FixaMinGata. It involves using the information that extracted from Instagram to create and post a report on FixaMinGata and to forward the feedback from authorities to Instagram users as well.

    This project runs under Ubuntu 12.04, and we have selected Python as the programming language. Besides these development environments, some additional modules are imported as well, such as Bottle, Selenium, Poster and Mechanize.

  • 169.
    Dubroca, Sabrina Marjorie
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Cross-Layer optimization in a satellite communication network2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis aims to improve a satellite communication network which carries both data streams and Voice over IP (VoIP) communication sessions with resource reservation. The resource reservations are made using the standard protocols for Traffic Engineering: MPLS-TE and RSVP-TE. The goal of this thesis project is to optimize the number of concurrent VoIP calls that can be made, in order to use the available bandwidth while maintaining a guaranteed Quality of Service (QoS) level, which is not possible in the existing system.

    This thesis proposes and evaluates a solution to this optimization problem in the specific context of a satellite modem system that was developed by Thales Communications. This optimization improves the system's ability to carry VoIP communications through better use of the available transmission resources. A solution to this problem would also increase the  exibility in bandwidth allocation within the modem system, and could provide a framework for future development.

    The proposed solution allows all of the reservable bandwidth to be used.  The amount of reservable bandwidth must be at least a little lower than the channel's available bandwidth in order to avoid congestion. Some areas of future work are proposed.

  • 170.
    Dully, Michael
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Traffic Safety Evaluation of Future Road Lighting Systems2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    While new road lighting technologies, either LED or adaptive road lighting systems, offer a wide range of unique potential benefits (mainly in terms of energy savings), it is necessary to evaluate the safety impacts of these technologies on road users. The literature survey shows that providing light on previous unlit roads has a positive effect on traffic safety. Reducing the amount of light has the opposite effect. These studies are usually conducted by using crash numbers, which makes it impossible to draw conclusions on changes in driving behaviour. Driving behaviour analyses need special approaches and indicators. Therefore indirect indicators such as speed and safety relationship, jerky driving and traffic conflict parameters are presented. The individual character of such data is difficult to deal with and limits big scale analyses. In order to have a practical example of such indicators a case study is conducted. Floating car data collected in Vienna is used to analyse travel speeds of taxi drivers at two LED test sites. A simple before-after analysis is used with data from January 2011 to May 2012 in order to examine an expected increase in speed due to a better visual performance of LED light. However the results show either no changes at all or a trend in speed reduction of 1km/h in average. Unfavourable test site locations might limit the significance of the results.

  • 171.
    Duong, Le
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    A model to predict the coverage of VHF transmissions2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    VHF står för "Very High Frequency" och är ett frekvensband som ligger i området 30 - 300 MHz. Maritim VHF är standard för Sjöfartsverket och fungerar över hela världen. Det är ett kommunikationssystem som bidrar till ökad säkerhet och kan rädda liv på sjön. Andra vanliga kommunikationssystem som mobiltelefoni fungerar inte tillförlitligt. Idag fungerar mobiltelefoni i stora delar av skärgården och längs kusterna men när det gäller kommunikation mellan fartyg längre ut till havs är den maritima VHF-kommunikationen överlägsen. Sjöfartsverket driver för sitt eget och kunders behov ett mobilradionätverk kallat kustradionätverket. Radiotrafiken i nätet sker både på Very High Frequency (VHF) och Medium frequency (MF). VHF-systemet är ett internationellt system som bland annat används till att kommunicera till sjöss och den trafiken befinner sig i frekvensbandet 155.5 - 162.025 MHz. Inom VHF-bandet finns det 55 kanaler. Kanalerna vid kustradiostationen kallas för duplexkanaler och innebär att kustradiostationerna sänder och tar emot signaler på två olika frekvenser. Radioutbredningen hos antennen som är installerad på basstationen har riktverkan i vissa riktningar och dämpningar i andra. Detta kan ses i strålningsdiagrammet under kapitlet "Täckningsmodell" och avsnittet antennen. Andra faktorer som kan påverka radioutbredningen är förluster i basstationenssystemet, topologin hos området mellan sändare och mottagare samt väderberoende utbredningsegenskaper. Genom att hitta de tänkbara faktorer som påverkar signalutbredningen kan en täckningsmodell förutses. Det är förluster som finns i basstationen, radiolänken samt förluster vid mottagarantennen.

  • 172.
    Dzaferagic, Samir
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Secure Session Mobility for VoIP2008Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    High data rate wireless packet data networks have made real-time IP based services available through mobile devices. At the same time, differences in the characteristics of radio technologies (802.11/WiFi and 3G networks) make seamless handoff across heterogeneous wireless networks difficult. Despite this, many believe that the ultimate goal of next generation networks (often referred to as the fourth generation) is to allow convergence of such dissimilar heterogeneous networks. Supporting voice over Internet Protocol in next-generation wireless systems is thought by some to require support for mobility and quality of service features. Currently a mobile node can experience interruptions or even sporadic disconnections of an on going real-time session due to handovers between both networks of different types and networks of the same type.

    Many tests have already been done in this area and one may wonder why it is worth spending even more time investigating it? This thesis focuses on the important problem of providing session security despite handovers between networks (be they operated by the same operator or different operators and be they the same link technologies or different). One of the goals in this thesis is to investigate how an ongoing speech session can continue despite a change in transmission media1. Additionally, a number of security threats that could occur due to the handover will be identified and presented. Finally, the most suitable solution to address these threats will be tested in a real environment. Eventual shortcomings and weaknesses will be identified and presented; along with suggestions for future work. 

    1 When utilizing IP over carriers such as wired Ethernet, WLAN, and 3G.

  • 173.
    Díez Rodríguez, Víctor
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi.
    Detournay, Jérôme
    Högskolan i Halmstad, Akademin för informationsteknologi.
    An Approach for Receiver-Side Awareness Control in Vehicular Ad-Hoc Networks2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Vehicular Ad-Hoc Network (VANET)s are a key element of Intelligent Transport System (ITS)s. One of the challenges in VANETs is dealing with awareness and congestion due to the high amount of messages received from the vehicles in communication range. As VANETs are used in critical applications, congestion on the receiver side caused by the buffering of the packets is a safety hazard. In this thesis, we propose a stream-wise queuing system on the receiver side and show how it improves the timeliness of the messages received and main- tains the awareness of the system in a congestion situation.

  • 174.
    Eamrurksiri, Techin
    Linköpings universitet, Institutionen för systemteknik, Kommunikationssystem. Linköpings universitet, Tekniska högskolan.
    Implementation and Analysis of Spectrum Sensing Algorithms for SIMO Links2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Cognitive radio is an autonomous transceiver that is continuously sensing theongoing communication in its environment, it then starts the communication whenever it is appropriate. Therefore, cognitive radio helps improving the spectrum utilization of the overall communication system. However, without suitable spectrum sensing techniques, cognitive radio would fail. Hence, in this thesis we investigate and implement various spectrum sensing algorithms via software defined radio for both single antenna and multiple antenna cases. The main communi-cation scheme that we are using is OFDM. Moreover, both computer simulations and real-world measurements, have also been done for comparison and analysis ofthe detector’s performance. The detectors we are using are based on correlationfunction of the received signal and generalized likelihood ratio test with its eigen-value. The results from the simulations and measurements are then representedas probability of missed detection curves for different signal to noise ratios. Ourresults show that the performance of the generalized likelihood ratio test baseddetectors are at least 2 dB better than the correlation based detector in our mea-surement. Moreover, our simulations show that they are able to outperform thecorrelation function detector by more than 6 dB. Although, generalized likelihoodratio test based detectors seem to be better than the correlation function baseddetector, it requires more computational power which may limit its practical use.

  • 175.
    Ebler, Mats
    et al.
    KTH, Tidigare Institutioner, Teleinformatik.
    Flodén, Anders
    KTH, Tidigare Institutioner, Teleinformatik.
    Mobility for Cordless Multimedia1995Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This project has developed a system for cordless multimedia business communication. It supports multimedia conferencing using existing applications across a mix of cordless and wired networks.

  • 176.
    Ebrahimi, Hamid
    KTH, Tidigare Institutioner, Teleinformatik. KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Linjelyssnare för Gränssnitt mot DECT-basestation1998Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    There purpose of this thesis was design and evaluate a device which would listen to the proprietary interface between a Private Automatic Branch Exchange (PBX) and a Digital Enhanced Cordless Telecommunications (DECT) basestation. The signal information has been transfered to a PC in order to collect and analyse data. The analysis has been limited to the bottom 4 layers. The software developed enables the display of the messages in either hex or clear text.

  • 177.
    Eckerström, Johan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Location Aware Communication2003Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Automotive telematic systems will be as common in future cars as ABS and airbags are in current cars. These systems will provide services such as navigation aid, automatic emergency alerts, traffic and road information, information about parking possibilities, tourist information, and personalized news. All these services need a communication link to the mobile Internet to be able to work properly. In this master’s thesis General Packet Radio Service, GPRS will be investigated and evaluated as a bearer for these kinds of services. A test application was built to test the location aware communication on the field. Upstream and downstream delays, possible bottlenecks in the network, connection set-up time, characteristics of different operators, and connection breakdowns where analyzed.

    The tests showed high network delays, and that many connection breakdowns occurred. The operators did not differ much when it comes to performance. One mayor drawback with GPRS is the low scalability with respect to operator’s lack of IP addresses, which will be discussed.

    Conclusions of the evaluation were that only certain location-based services are suitable over GPRS with the quality of today.

  • 178.
    Edström, Johan
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för data-, elektro- och lantmäteriteknik.
    Redovisning av lantmäterimyndigheternas handläggningstider och hur de påverkar byggbranschen2017Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Att behovet av bostäder är mycket stort och kommer att vara så under många år är välkänt. För att hantera det akuta läget behöver byggprocessen snabbas på.  Den 19:e januari 2017 publicerades en artikel på regeringens hemsida som beskriver att lantmäteriets handläggningstider behöver granskas då de långa handläggningstiderna saktar ner byggprocessen och därmed påverkar samhällsbyggnadsprocessen negativt.  Lantmäteriet är myndigheterna som, något förenklat, jobbar med att bestämma, reglera och stycka av fastighetsgränser. Detta innebär att lantmäteriet har en viktig roll i Planprocessen. Framförallt under detaljplanearbetet.  Denna C-uppsats har genomförts på Högskolan Väst med syfte att undersöka hur lantmäteriets handläggningstider påverkar bygg och fastighetsbolagen.

     Av Sveriges 39 kommunala lantmäterimyndigheter har 29 bidragit med handläggningsstatistik. Studiens resultat har visat att handläggningstiderna på kommunala lantmäterimyndigheterna i snitt är 47,5 veckor 2016 Hos statliga lantmäteriet låg motsvarande värde 2016 på 55,1 veckor. Studien indikerar ganska tydligt att handläggningstiderna är för långa med tanke på vad byggbranschen har för krav. Majoriteten inom byggbranschen anser att en handläggningstid längre än 26 veckor är orimligt i de flesta typer av ärenden.  I övrigt har studien visat att byggbranschen är nöjd med lantmäteriets prestationer.  2016 trädde en ny paragraf i kraft i ledningsrättslagen som ska ge rätt till bredband för alla Sveriges invånare inom max 4 månader efter ansökan.  Detta innebär att lantmäteriet kan bli tvungna att ge förtur i dessa typer av ärenden och därmed kan övriga handläggningstider komma att påverkas. Resultatet har visat att det finns fyra möjligheter att få förtur i kön men om den nya regeln i ledningsrättslagen har påverkat handläggningstiderna är idag för tidigt att säga.   

  • 179.
    Edström, Petter
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Overhead Impacts on Long-Term Evolution Radio Networks2007Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    As a result of the constant efforts to improve mobile system performance and spectral efficiency, the 3GPP standardization forum is currently defining new architectural and functional requirements that hope to ensure long-term evolution (specifically defined as the “Long-Term Evolution (LTE) concept”) and general future competitiveness of the 2G and 3G radio access technologies.

    Previous discussions on LTE efficiency have been focused on general assumptions on signaling overhead and overall system capacity, based on experience from existing mobile systems. However, as 3GPP standardization has become more mature (although not yet settled), there is a need to investigate how different potential LTE services will be affected by the use of available overhead information and basic scheduling algorithms. This thesis investigates the lower protocol layers’ overhead impacts on the downlink for different packet switched services, in an LTE radio access network (RAN).

    Results show that the use of RTP/TCP/IP header compression (ROHC) is the single most important factor to reduce payload overhead, for packet sizes of ~1kB or smaller. However, for packets larger than ~1 kB, the use of ROHC becomes insignificant.

    Protocol headers – including the AMR frame header, RLC/MAC headers, and CRC where applicable – remain the largest part of payload overhead regardless of packet size and header compression (ROHC). For VoIP over the UDP protocol (with ROHC), RLC/MAC headers constitute the largest part of protocol headers.

    For TCP/IP applications (without ROHC), TCP/IP headers are predominant. Services that require packet sizes beyond ~1 kB will require about the same power per payload bit regardless of percentage of payload overhead.

  • 180.
    Egman, Tommy
    KTH, Tidigare Institutioner, Teleinformatik.
    Solution Verification for Call Centre in BC101999Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This report is about how a Call Centre solution can be verified and what different tools that are needed to be able to do a proper verification. The Call Centre that are being verified is Ericsson’'s MD110 Call Centre for BC10. The different parts that the report is focusing on are how to generate Telephony traffic into the MD110 over ISDN, to measure LAN activities, and to generate Call Centre Agents behaviour. The report will come to conclusions that certain ways of handling the solution can improve the performance of the Call Centre.

  • 181.
    Egnell, Jakob
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska högskolan.
    Network usage profiling for applications on the Android smart phone2012Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [en]

    Android, a platform for smartphones and mobile devices, is becoming more and more present in the market. Nevertheless, the battery runtime of smartphones is short and strongly influenced by the network usage. Some proposals exist to reduce the energy consumption associated to the network usage and increase the smartphone runtime. But for adjusting them for a real improvement it is required to study the network utilisation triggered by the smartphone applications. With this analysis the applications communication patterns can be obtained and used to predict the network usage and the amount of data expected.

    In order to gather network statistics of the running applications, a logger application is implemented for the Android platform to log network statistics of running applications. The statistics are analysed on a PC computer to obtain the applications' communication patterns. A number of applications are selected, sorted by the rankings of downloads and type. A detailed analysis of the network usage is presented. This analysis identifies some of their patterns, some application characteristics and groups of applications from the determined network usage. The network usages for applications with similar functionalities are compared and lessons learnt from the analysis are discussed. Finally, some improvements for our logger application and analysis are discussed.

  • 182.
    Eidlert, Fredrik
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Messaging and positioning in a dynamic TETRA environment2009Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Advanced communication with capabilities such as voice, data, and messaging usually requires an infrastructure with base stations, servers, and etcetera. The TETRA technology offers such communication not only in TMO (infrastructure-based network) but also in DMO where all nodes communicate directly (or via a repeater) with each other.

    This master’s thesis concerns messaging (specifically short messages) in a dynamic multi link TETRA DMO network. It examines what type of messaging technique to use and how to do path selection. The messages will be clear text, status, and GPS location information. The solution is implemented as a part of the ISIS software (which is developed by Know IT Dataunit). The planned multi link-part of the thesis could not be tested, so there is no implementation or evaluation of this. The evaluation of the implementation concerning sending and reception of messages shows that the proposed solution fulfils the demands for this kind of product. During a four day long test, messages (short text messages and positioning messages) were sent and received while a normal number of voice conversations took place, without packet loss.

  • 183.
    Ejigayehu Teka, Kaleab
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Energy Effcient Design and Bandwidth Assignment in Wireless Access Networks2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In recent years, traffic demands and quality of service requirements in cellular networks is increasing rapidly. Network operators deploymore number of base stations or increase the transmission power of the existing deployment in order to satisfy this user demand. This increases theenergy consumption and operational cost of cellular networks as well as the capital expenditures. Energy efficient design of cellular networks is a promising strategy to reduce energy consumption. Proper utilization of spectrum, high spectral efficiency and application of interference mitigation approaches provides more capacity in wireless access. Traditional bandwidth allocationschemes are intended to maximize the throughput of the system and increase the quality of service. Different resource allocation methods have been proposed as a solution for energy efficient resource management in wireless access networks. We investigate the efficiency of different resource allocation methods and the effect of excess capacity for reducing the total power consumption.

    In this thesis we intend to analyze the impact of excess capacity on reducing energy consumption in the network. Performance of different bandwidth allocation schemes is studied in order to reduce power consumption as much as possible. Three different resource allocation schemes have been studied depending on the way they distribute available resourcesblocks(RBs) to users. The first scheme is equal bandwidth allocation where users are assigned resources equally in a round robin manner. The second scheme is proportional bandwidth allocation scheme with residuals. This scheme assigns the whole resources considering the quality of service of users. The third one is proportional resource allocation without residuals. Here resources are allocated until every user meets the required quality of service and then leaves the residual resources.

  • 184.
    Ejner, Mikael
    KTH, Tidigare Institutioner, Teleinformatik.
    Bi-directional Differentiated Services in aBroadband Access Server1999Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Quality of Service (QoS) is a highly desired feature of an IP network. The best-effort quality of traffic behaviour that the Internet provides by default today is not enough for certain timing-, mission- and throughput-critical applications such as video conferencing. One approach to achieve Quality of Service is Differentiated Services (DiffServ). However, one shortcoming of DiffServ is that it is unidirectional. This means that a user paying for premium FTP service will, when downloading a file, only get premium service for the requests, not for the actual file transfer.

    The goal of this project was to find a suitable method for making DiffServ bi-directional.

    This report presents the background and some available options, and motivates a preferred solution for the bi-directional Differentiated Services problem. The preferred option is, as the discussion shows, a centralised server-based solution with bi-directional DiffServ as an integrated feature of a policy-based network. A primitive prototype system was implemented to validate the concept.

  • 185.
    Eklund, Martin
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Ståhlberg, Patrik
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Distributed denial of service attacks: Protection, Mitigation, and Economic Consequences2015Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Distributed Denial of Service attacks is a problem that constantly threatens companies that rely on the internet for major parts of their business. A successful DDoS attack that manages to penetrate a company’s network can lead to devastating damages in the form of lost income, reduced productivity, increase in costs, and damage to the company’s image and reputation.

    The different DDoS attacks are many and of different character and often Offer different parts of the network, which makes it very difficult to defend against. It is also very clear that DDoS attacks are increasing in both numbers and size every year. From our experiments we have proven that anyone with little knowledge and limited resources can perform DDoS attacks that will make a website unavailable. This fact should cause companies that base their business on the internet, aware that they are likely to someday be subject to a DDoS attack.

    From our research we have found a variety of different DDoS solutions on the market that promise to offer protection. Many of which claim to protect against all different types of DDoS attacks. In practice it is impossible to find something that guarantees 100% safety. According to earlier research in the field, there are many different ways of protecting a network against DDoS attacks, e.g. via Software Defined Networking, Hop-Count Filtering, or Kill-bots.

    Our own tests show that a virtual firewall can offer protection against DDoS attacks on a low scale, but that such a solution has a number of weaknesses. If the firewall does protect the website, the attacker could instead shift to attacking the firewall itself.

    Our research also shows that the most common motives behind DDoS attacks are criminal purposes. Criminals use DDoS attacks to earn money by offering directed DDoS attacks against websites or by trying to blackmail companies into paying a fee for not being attacked.

    We have also seen that the economic consequence of DDoS attacks are devastating if not handled with a sufficiently fast response. After investigating the e-commerce company CDON.com we learned that they could potentially lose roughly 36 410 SEK per minute when a DDoS attack is underway against them.

    In today’s business climate it is important for companies to be able to rely on the internet for their activity and for customers to have easy access to the company’s products and services. However, companies’ websites are being attacked and thus these companies need an explicit plan of how to mitigate such attacks.

  • 186.
    Eklöf, William
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Adaptive Video Streaming: Adapting video quality to radio links with different characteristics2008Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    During the last decade, the data rates provided by mobile networks have improved to the point that it is now feasible to provide richer services, such as streaming multimedia, to mobile users. However, due to factors such as radio interference and cell load, the throughput available to a client varies over time. If the throughput available to a client decreases below the media’s bit rate, the client’s buffer will eventually become empty. This causes the client to enter a period of rebuffering, which degrades user experience. In order to avoid this, a streaming server may provide the media at different bit rates, thereby allowing the media’s bit rate (and quality) to be modified to fit the client’s bandwidth. This is referred to as adaptive streaming.

    The aim of this thesis is to devise an algorithm to find the media quality most suitable for a specific client, focusing on how to detect that the user is able to receive content at a higher rate. The goal for such an algorithm is to avoid depleting the client buffer, while utilizing as much of the bandwidth available as possible without overflowing the buffers in the network. In particular, this thesis looks into the difficult problem of how to do adaptation for live content and how to switch to a content version with higher bitrate and quality in an optimal way.

    This thesis examines if existing adaptation mechanisms can be improved by considering the characteristics of different mobile networks. In order to achieve this, a study of mobile networks currently in use has been conducted, as well as experiments with streaming over live networks. The experiments and study indicate that the increased available throughput can not be detected by passive monitoring of client feedback. Furthermore, a higher data rate carrier will not be allocated to a client in 3G networks, unless the client is sufficiently utilizing the current carrier. This means that a streaming server must modify its sending rate in order to find its maximum throughput and to force allocation of a higher data rate carrier. Different methods for achieving this are examined and discussed and an algorithm based upon these ideas was implemented and evaluated. It is shown that increasing the transmission rate by introducing stuffed packets in the media stream allows the server to find the optimal bit rate for live video streams without switching up to a bit rate which the network can not support.

    This thesis was carried out during the summer and autumn of 2008 at Ericsson Research, Multimedia Technologies in Kista, Sweden.

  • 187.
    Ekman, Björn
    Linköpings universitet, Institutionen för systemteknik, Kommunikationssystem.
    Machine Learning for Beam Based Mobility Optimization in NR2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    One option for enabling mobility between 5G nodes is to use a set of area-fixed reference beams in the downlink direction from each node. To save power these reference beams should be turned on only on demand, i.e. only if a mobile needs it. An User Equipment (UE) moving out of a beam's coverage will require a switch from one beam to another, preferably without having to turn on all possible beams to find out which one is the best.

    This thesis investigates how to transform the beam selection problem into a format suitable for machine learning and how good such solutions are compared to baseline models. The baseline models considered were beam overlap and average Reference Signal Received Power (RSRP), both building beam-to-beam maps. Emphasis in the thesis was on handovers between nodes and finding the beam with the highest RSRP. Beam-hit-rate and RSRP-difference (selected minus best) were key performance indicators and were compared for different numbers of activated beams.

    The problem was modeled as a Multiple Output Regression (MOR) problem and as a Multi-Class Classification (MCC) problem. Both problems are possible to solve with the random forest model, which was the learning model of choice during this work. An Ericsson simulator was used to simulate and collect data from a seven-site scenario with 40 UEs. Primary features available were the current serving beam index and its RSRP. Additional features, like position and distance, were suggested, though many ended up being limited either by the simulated scenario or by the cost of acquiring the feature in a real-world scenario.

    Using primary features only, learned models' performance were equal to or worse than the baseline models' performance. Adding distance improved the performance considerably, beating the baseline models, but still leaving room for more improvements.

  • 188.
    Ekman, Rasmus
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Automobile Control Systems: Transition from Controller Area Networks to Ethernets2014Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Due to concerns about the negative impacts of powering vehicles using fossil fuel and the future availability of fossil fuel, there has been an increased focus on electric vehicles. However, current electric vehicle energy efficiency is a key problem as these vehicles are not as efficient as fossil-fueled vehicles. One way of decreasing a vehicle’s energy consumption is to reduce the weight of the vehicle, while still ensuring the safety and reliability of the vehicle. Controller Area Network (CAN) systems have been used in vehicles to realize real-time applications, however the low peak data rates of CAN have begun to limit the applications that can be realized.

    This bachelor’s thesis project focuses on secure communication within a vehicle using Ethernet. Additionally, the use of Power over Ethernet can be used for powering some of the network attached devices within the vehicle. The goal is to reduce the number of components and the weight of the vehicle while continuing to ensure the security and reliability of the communication – even when the network grows in size (either in physical size or in number of connected devices).

    This thesis shows that an Ethernet based system can serve as a possible replacement candidate for the CAN system due to its low latencies and high bandwidth. Ethernet is also a very scalable system with none of the limitations that a CAN system have.

  • 189.
    Ekramian, Elnaz
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för datalogi och datorsystemteknik.
    Automation of the test methods for packet loss and packet loss duration in the Ixia platform2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Today’s technology has a strong tendency towards automation. As a matter of fact, the tremendous improvement of science in the recent years brought new ideas regarding to accelerate the scientific process that is not separated of automation. This paper also deals with automation of manual tests that were used to analyze packet loss and packet loss duration in a network. These two metrics were chosen based on their importance they have in the communication technology, also based on the weak points that were found in the manual processes. This experiment is done in the Ixia platform that was an appropriate test bed to design an automation framework.After a comprehensive research on network and communication we could choose packet loss and packet loss duration as two important parameters that are under test several times per day. Therefore, based on the properties that are used for automation, these two metrics had the priority compare to other metrics. We could create a framework that works correspond to the manual test process. For this purpose, Tcl programming language is used. The script that was written with this high-level language can communicate with the graphical user interface, configuring all the connected devices, measuring mentioned metrics and ultimately save the result in a csv file.Finally, we could reach to the main objective of this project which was to show how positively automatic method can affect on the quality of test in terms of accuracy, time and manpower saving.

  • 190.
    Ekstrand, Magnus
    KTH, Tidigare Institutioner, Teleinformatik.
    Traffic Prioritization Subject to Cost1999Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In order to carry real-time traffic like video, IP networks -- especially intranets -- recently began to deal with different levels of priority for communication flows. Traffic prioritization is the key to meeting the demands of real-time traffic, which are much more stringent than mere data traffic, such as file transfers. Now that the question: "How should we specify different levels of priority?" is reasonably understood, the challenge is to answer this new one: "How should we charge for these different levels of priority?"

    This document discusses the introduction of Quality of Service (QoS) in the corporate network of a large industrial enterprise. Its main contributions are a charging model for different types of traffic with different levels of priority, and a network simulation for verifying the impact of a QoS implementation.

  • 191.
    Elbashir, Khalid
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Trusted Execution Environments for Open vSwitch: A security enabler for the 5G mobile network2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The advent of virtualization introduced the need for virtual switches to interconnect virtual machines deployed in a cloud infrastructure. With Software Defined Networking (SDN), a central controller can configure these virtual switches. Virtual switches execute on commodity operating systems. Open vSwitch is an open source project that is widely used in production cloud environments. If an adversary gains access with full privileges to the operating system hosting the virtual switch, then Open vSwitch becomes vulnerable to a variety of different attacks that could compromise the whole network.

    The purpose of this thesis project is to improve the security of Open vSwitch implementations in order to ensure that only authenticated switches and controllers can communicate with each other, while maintaining code integrity and confidentiality of keys and certificates. The thesis project proposes a design and shows an implementation that leverages Intel® Safe Guard Extensions (SGX) technology. A new library, TLSonSGX, is implemented. This library replaces the use of the OpenSSL library in Open vSwitch. In addition to implementing standard Transport Level Security (TLS) connectivity, TLSonSGX confines TLS communication in the protected memory enclave and hence protects TLS sensitive components necessary to provide confidentiality and integrity, such as private keys and negotiated symmetric keys. Moreover, TLSonSGX introduces new, secure, and automatic means to generate keys and obtain signed certificates from a central Certificate Authority that validates using Linux Integrity Measurements Architecture (IMA) that the Open vSwitch binaries have not been tampered with before issuing a signed certificate. The generated keys and obtained certificates are stored in the memory enclave and hence never exposed as plaintext outside the enclave. This new mechanism is a replacement for the existing manual and unsecure procedures (as described in Open vSwitch project).

    A security analysis of the system is provided as well as an examination of performance impact of the use of a trusted execution environment. Results show that generating keys and certificates using TLSonSGX takes less than 0.5 seconds while adding 30% latency overhead for the first packet in a flow compared to using OpenSSL when both are executed on Intel® CoreTM i7-6600U processor clocked at 2.6 GHz. These results show that TLSonSGX can enhance Open vSwitch security and reduce its TLS configuration overhead.

  • 192.
    Eldh, Axel Fant
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Kirvesniemi, Mattias
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Economical and Political Implications of DNSSEC Deployment2010Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    This report provides a summary of the current deployment of Domain Name System (DNS) Security Extensions (DNSSEC) as well as a discussion of future deployments and deployment rates. It analyses the problems that have occurred and considers those that may arise. This thesis focuses mainly on economical and political perspectives, rather than the technical perspective used in most reports regarding this subject.

    There were four areas that needed to be examined: the technical basis for DNSSEC, the deployment process, the current level of DNSSEC deployment, and the opinions regarding this subject. The information about the deployment process was obtained mainly through articles, but also through reports from organizations such as the Internet Corporation for Assigned Names and Numbers (ICANN) and the Electronic Privacy Information Centre. To acquire up to date data on DNSSEC deployment, SecSpider was used to research the level of deployment as of 2010-05-06. The search was restricted to the generic Top Level Domains (gTLDs) and country code TLDs (ccTLDs) of the top 20 countries in terms of Internet usage as well as the OECD countries. This restriction was made to narrow down the scope to the TLDs where DNSSEC would have the greatest impact. The “Top 20” comprises 77.27 % of the world’s Internet users, hence it is where DNSSEC deployment would affect the most people. The OECD is in this thesis considered a sufficient ly large selection to represent themost technologically advanced and economically powerful countries in the world regardless of size. Major powers such as China, India, and Russia while not included in the OECD are represented in the “Top 20” due to their size.

    Our results show that some major TLDs have implemented DNSSEC and that the rate of deployment has increased in the last few years. However, the level of DNSSEC deployment in the TLDs is still rather low; 15.00 % in the gTLDs and ccTLDs of the Top 20 countries in Internet usage, and 20.00 % in the OECD’s ccTLDs. Deployment in the root is ongoing during spring 2010, this could have a great impact on the rate of deployment as deployment in a gTLD or ccTLD is highly dependent on deployment high up in the hierarchy due to the nature of DNSSEC. It is unlikely that corporations would implement DNSSEC without a potential return on investment (ROI) and management control measures from governments might be required to increase deployment pace at the lower levels of the DNS hierarchy.

  • 193.
    Eldh, Erik
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Cloud connectivity for embedded systems2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Deploying an embedded system to act as a controller for electronics is not new.  Today these kinds of systems are all around us and are used for a multitude of purposes. In contrast, cloud computing is a relatively new approach for computing as a whole. This thesis project explores these two technologies in order to create a bridge between these two wildly different platforms. Such a bridge should enable new ways of exposing features and doing maintenance on embedded devices. This could save companies not only time and money while dealing with maintenance tasks for embedded systems, but this should also avoid the needed to host this maintenance software on dedicated servers – rather these tasks could use cloud resources only when needed. This thesis explores such a bridge and presents techniques suitable for joining these two computing paradigms together.

    Exploring what is included in cloud computing by examining available technologies for deployment is important to be able to get a picture of what the market has to offer. More importantly is how such a deployment can be done and what the benefits are. How technologies such as databases, load-balancers, and computing environments have been adapted to a cloud environment and what draw-backs and new features are available in this environment are of interest and how a solution can exploit these features in a real-world scenario.  Three different cloud providers and their products have been presented in order to create an overview of the current offerings.  In order to realize a solution a way of communicating and exchanging data is presented and discussed. Again to realize the concept in a real-world scenario.

    This thesis presents the concept of cloud connectivity for embedded systems. Following this the thesis describes a prototype of how such a solution could be realized and utilized. The thesis evaluates current cloud providers in terms of the requirements of the prototype.

    A middle-ware solution drawing strengths from the services offered by cloud vendors for deployment at a vendor is proposed. This middle-ware acts in a stateless manner to provide communication and bridging of functionality between two parties with different capabilities. This approach creates a flexible common ground for end-user clients and reduces the burden of having the embedded systems themselves process and distribute information to the clients.  The solution also provides and abstraction of the embedded systems further securing the communication with the systems by it only being enabled for valid middle-ware services.

  • 194.
    Elofsson, Milosz
    KTH, Tidigare Institutioner, Teleinformatik.
    RAS in VoIP Networks1999Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Traditionally network access servers are used to provide access services for remote dial-up users who want to access packet switched networks. The users can dial-up over public switched telephone network connection when they want to access the Internet or a Corporate LAN. The construction of new telephony networks based on IP-technology gives the possibility to integrate new services in these networks. Such a new service could be a remote access service integrated in the Media Gateways used for IP-telephony. The main goal with this Master Thesis project is to evaluate possible architectures for integrating distributed remote access service in Voice over IP networks.

    The conclusion of my evaluation is that the best way to integrate the dial-up network access service in VoIP networks is the L2TP solution. Traditionally a PPP session is established between the dial-up user and the network access server over a PSTN/ISDN connection. In the L2TP solution a Media Gateway terminates the physical and data link layer and use the L2TP protocol to tunnel the PPP session to a network access server over the IP network. The PPP session is terminated on the network access server.

    Another interesting solution is the PPP solution where the Media Gateway and a router handle all the dial-up network access features that a traditional network access server normally provides. The PPP session is terminated directly on the Media Gateway and the traffic is forwarded out on the external network by the router. In this solution the network access server is no longer needed.

  • 195.
    Emil, Ceder
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Detect misconnected Telia customers in the network2015Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [en]

    Abstract

    The project consists of creating a program that can detect fiber customers that has been misconnected on the switch connecting them to the Telia network. The program will be able compare what customer is configured on the port against the customer who has received and the Telia router connected to the port. If there is a mismatch then there is a chance the customer has been misconnected.

    The comparison can be done because the unique serial number of the Telia router is both registered in the session database over active Telia routers and also in the database of products delivered to customers. This will only work on customers with Telia routers, but it will still be helpful as it would give an indication of what switches might have misconnect customers. If there is one misconnected customer on a switch there is likely to be more.

    The program was created with MySQL and PHP in the form of a web tool. The program can be run against certain switches or the program can be run against all active Telia routers and look for mismatches.

    To make the program work it required access to the session database over active Telia routers, the database over customer configuration on the port and the database over Telia routers sent to customers. These are three different systems and because of the time constraint only a part of the data was used or retrieved from testing environments.

    With the available data the program could do the comparison against 8627 customers and of those 303 customers had a mismatch in the comparison. This does not necessarily mean that all of them are misconnected. In most cases it was another person in the household receiving the Telia router than the person that was signed up on Telia services. This could be sort out by ensuring that the person receiving the Telia router also was signed up to a Telia service. This left 57 customers out of the 303. Out of those 57 customers a part of them had special services and some had split the services on two persons in one household. After sorting them out manually there was around 15 customers left who was likely misconnected

    There is still no way to be certain those 15 customer are misconnected, however there a possibility they are and if there are several mismatches on a single switch it is certainly worth investigating further as it is a large possibility there are misconnected customers.

  • 196.
    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.

  • 197.
    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. 

  • 198.
    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.

  • 199.
    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.

  • 200.
    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.

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