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  • 1.
    Abad Caballero, Israel Manuel
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Secure Mobile Voice over IP2003Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Voice over IP (VoIP) can be defined as the ability to make phone calls and to send faxes (i.e., to do everything we can do today with the Public Switched Telephone Network, PSTN) over IP−based data networks with a suitable quality of service and potentially a superior cost/benefit ratio. There is a desire to provide (VoIP) with the suitable security without effecting the performance of this technology. This becomes even more important when VoIP utilizes wireless technologies as the data networks (such as Wireless Local Area Networks, WLAN), given the bandwidth and other constraints of wireless environments, and the data processing costs of the security mechanisms. As for many other (secure) applications, we should consider the security in Mobile VoIP as a chain, where every link, from the secure establishment to the secure termination of a call, must be secure in order to maintain the security of the entire process.

    This document presents a solution to these issues, providing a secure model for Mobile VoIP that minimizes the processing costs and the bandwidth consumption. This is mainly achieved by making use of high− throughput, low packet expansion security protocols (such as the Secure Real−Time Protocol, SRTP); and high−speed encryption algorithms (such as the Advanced Encryption Standard, AES).

    In the thesis I describe in detail the problem and its alternative solutions. I also describe in detail the selected solution and the protocols and mechanisms this solution utilizes, such as the Transport Layer Security (TLS) for securing the Session Initiation Protocol (SIP), the Real−Time Protocol (RTP) profile Secure Real−Time Protocol (SRTP) for securing the media data transport , and the Multimedia Internet KEYing (MIKEY) as the key−management protocol. Moreover, an implementation of SRTP, called MINIsrtp, is also provided. The oral presentation will provide an overview of these topics, with an in depth examination of those parts which were the most significant or unexpectedly difficult.

    Regarding my implementation, evaluation, and testing of the model, this project in mainly focused on the security for the media stream (SRTP). However, thorough theoretical work has also been performed and will be presented, which includes other aspects, such as the establishment and termination of the call (using SIP) and the key−management protocol (MIKEY).

  • 2.
    Abad Camarero, Daniel
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Performance analysis of IPv4 / IPv6 protocols over the third generation mobile network2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Currently, the IPv4 protocol is heavily used by institutions, companies and individuals, but every day there is a higher number of devices connected to the network such as home appliances, mobile phones or tablets. Each machine or device needs to have its own IP address to communicate with other machines connected to Internet. This implies the need for multiple IP addresses for a single user and the current protocol begins to show some deficiencies due to IPv4 address space exhaustion. Therefore, for several years experts have been working on an IP protocol update: the IPv6 128-bit version can address up to about 340 quadrillion system devices concurrently. With IPv6, today, every person on the planet could have millions of devices simultaneously connected to the Internet.

    The choice of the IP protocol version affects the performance of the UMTS mobile network and the browsers as well. The aim of the project is to measure how the IPv6 protocol performs compared to the previous IPv4 protocol. It is expected that the IPv6 protocol generates a smaller amount of signalling and less time is required to fully load a web page. We have analysed some KPIs (IP data, signalling, web load time and battery) in lab environment using Smartphones, to observe the behaviour of both, the network and the device.  The main conclusion of the thesis is that IPv6 really behaves as expected and generates savings in signalling, although the IP data generated is larger due to the size of the headers. However, there is still much work as only the most important webpages and the applications with a high level of market penetration operate well over the IPv6 protocol.

  • 3.
    Abdul Aziz Hasan Ali, Aamir
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Shahzad, Muhammad Adil
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    A Joint Subcarrier/Power allocation Scheme for OFDMA-based Cellular Networks2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The assignment of this master thesis consists of initiating power, subcarrier allocation in a dynamic FFR based scheme designed for multi-cell OFDMA networks and to enhance the throughput of all center users in bandwidth hungry borrower cells (overloaded cells) which was previously degraded by original FFR3 scheme as a result of partitioning of system bandwidth into center and edge bands respectively. The method uses band borrowing to compensate center user’s throughput loss in a semi and fully overloaded system. The scheme uses dynamic programming method (0/1 knapsack problem) to bargain an edge band on various power levels and tends to check the best combination (power and sub-carrier) which the system can utilize while still maintaining acceptable throughput loss for the users at the edge of the neighboring cell (lender cell).

    The algorithm consists of generating a borrowing request to neighboring cells for utilizing their edge bands by the overloaded borrower cell if their average center user throughput reaches below a minimum threshold value set in the system. The borrowing method uses 0/1 knapsack problem to capture an edge band based on limiting factors of total cost in average throughput losses by neighbors (Ci) and Un (tolerable mean user edge user throughput loss by lending cell). While solving knapsack problem the lender (neighbors) will check Ci and Un before granting the right to use its edge band. The later stage requires reducing subcarrier power level in order to utilize the lenders edge band using "soft borrower" mode. The borrowed sub-carriers will be activated take power from the original center band sub-carriers of the overloaded cell by taking into account the interference between the lender and the borrower. In case of negative (0) reply from the lender cell after the first request, multiple requests are generated at reduce power level at every step to order to acquire more bands. If a neighbor has band borrowing requests from multiple overloaded base stations, the band will be granted to the one which gives minimal loss in terms of throughput to the lender cell.

    The simulation results are analyzed w.r.t reuse-1 and FFR3 scheme of a multi cell regular and irregular scenarios comprising of lightly to heavily overloaded cells with various subcarrier allocation patterns. An overhead and time assessment is also presented between borrower and lender cells. Simulation results show an increase of 60% in center user’s throughput w.r.t original FFR3 scheme with an acceptable loss of 18% at the edges in complex overloaded scenarios while the overall system throughout increases by 35%.

  • 4.
    Adigozalov, Niyaz
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    The Intelligent Use of Multiple Interfaces: Using multiplexing to reduce the overhead for small packets2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Long-Term Evolution (LTE) is the latest development in wide area cellular mobile network technology. In contrast with the earlier generations of circuit-switched mobile networks, LTE is all-IP packet-switched network. Both voice and data are sent inside IP packets. Voice over IP (VoIP) is used to provide voice service to LTE users. The speech frames are encapsulated into real-time protocol (RTP) packets and sent over the network. The underlying UDP and IP layers prepend their headers to this small RTP packet resulting in a relatively high overhead. The small size of the RTP packets containing voice/audio leads to an overhead problem as the protocol overhead is in addition to the large LTE frame overhead, thus wasting network resources. This master’s thesis project proposes to multiplex RTP and data packets at the user’s device as a solution to reduce the overhead. Moreover, the capability of modern user devices to switch between several interfaces (such as LTE and WLAN), is taken into account and the multiplexing of multiple traffic flows or a single traffic flow are studied in the case of a vertical handover. Performance and cost metrics are used to evaluate different potential demultiplexing points, and then the best possible demultiplexing point is identified. The results of this evaluation show that several demultiplexing points can be used based on the operator’s needs. The increased packet payload size increases the energy efficiency of LTE and may avoid the need of the UE to switch to WLAN to save power. In addition, to ensure high quality of service for VoIP traffic, the simultaneous use of multiple interfaces is efficient if the multiplexer is enabled. The multiplexing solution proposed by this thesis is also fully compatible with any virtual private network encapsulation protocol.

  • 5.
    af Sandeberg, Joakim
    KTH, School of Information and Communication Technology (ICT).
    Graphical system visualization and flow display: A visual representation of an authentication, authorization, and accounting backend2016Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Displaying the architecture of a software system is not a simple task. Showing all of the available information will unnecessarily complicate the view, while showing too little might render the view unhelpful. Furthermore, showing the dynamics of the operation of such a system is even more challenging.

    This thesis project describes the development of a graphical tool that can both display the configuration of an advanced authentication, authorization, and accounting (AAA) system and the messages passed between nodes in the system.  The solution described uses force-based graph layouts coupled with adaptive filters as well as vector-based rendering to deliver a view of the status of the system. Force-based layout spreads out the nodes in an adaptive fashion. The adaptive filters starts by showing what is most often the most relevant information, but can be configured by the user. Finally, the vector based rendering offers unlimited zoom into the individual nodes in the graph in order to display additional detailed information.

    Unified Modeling Language (UML) sequence charts are used to display the message flow inside the system (both between nodes and inside individual nodes).

    To validate the results of this thesis project each iteration of the design was evaluated through meetings with the staff at Aptilo Networks. These meetings provided feedback on the direction the project was taking as well as provided input (such as ideas for features to implement).

    The result of this thesis project shows a way to display the status of an AAA system with multiple properties displayed at the same time. It combines this with a view of the flow of messages and application of policies in the network via a dynamically generated UML sequence diagram. As a result human operators are able to see both the system’s architecture and the dynamics of its operation using the same user interface. This integrated view should enable more effective management of the AAA system and facilitate responding to problems and attacks.

  • 6.
    Af Ugglas, Mikael
    KTH, Superseded Departments, Teleinformatics.
    Accounting Management on a DTM Network1999Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Large investments are currently being made for the infrastructure of voice and data services. The network providers’ revenues consist of fees from the users of the network. Until today it has been difficult to charge for the actual usage, instead so-called flat rate charging has been applied.

    Dynamic synchronous Transfer Mode (DTM) is a circuit switched technique that is designed to meet the requirements of future multimedia services. This includes support for real time applications and high throughput. Physically separated channels, whose capacity can easily be adjusted to the users’ demands, provide the service. The channels and their guaranteed service make DTM a very interesting technique when it comes to charging for network usage, as the characteristics of the channel can be easily described by relatively few parameters.

    This thesis describes how accounting management can be applied on a DTM network. It identifies the parameters that need to be collected and describes how to gather these parameters into call data records (CDRs). Furthermore, it outlines how the transportation of the CDRs to the network providers’ billing system can be performed.

  • 7.
    Aguilar, Antonio
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    A Patient Identification System using RFID and IEEE 802.11b Wireless Networks2007Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The recent increased focus on patient safety in hospitals has yielded a flood of new technologies and tools seeking to improve the quality of patient care at the point of care. Hospitals are complex institutions by nature, and are constantly challenged to improve the quality of healthcare delivered to patients while trying to reduce the rate of medical errors and improve patient safety. Here a simple mistake such as patient misidentification, specimen misidentification, wrong medication, or wrong blood transfusion can cause the loss of a patient’s life. Misidentification of patients is a common problem that many hospitals face on the daily basis. Patient misidentification is one of the leading causes of medical errors and medical malpractice in hospitals and it has been recognised as a serious risk to patient safety.

    Recent studies have shown that an increasing number of medical errors are primarily caused by adverse drug events which are caused directly or indirectly by incorrect patient identification. In recognition of the increasing threat to patient safety, it is important for hospitals to prevent these medical errors from happening by adopting a suitable patient identification system that can improve upon current safety procedures.

    The focus of this master’s thesis is the design, implementation, and evaluation of a handheld-based patient identification system that uses radio frequency identification (RFID) and IEEE 802.11b wireless local area networks to identify patients. In this solution, each patient is given a RFID wristband which contains demographic information (patient ID number, ward number, hospital code, etc.) of the patient. A handheld device equipped with IEEE 802.11b wireless local area network connectivity and a RFID reader is then used by the medical staff to read the patient’s wristband, identify the patient, and access the relevant records of this patient.

    This work was carried out at the Department of Medical Physics and Bioengineering at the University College Hospital Galway (UCHG), Ireland and the National University of Ireland, Galway.

  • 8.
    Ahmad, Aftab
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Performance of MLSE over Fading Channels2013Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    This work examines the performance of a wireless transceiver system. The environment is indoor channelsimulated by Rayleigh and Rician fading channels. The modulation scheme implemented is GMSK inthe transmitter. In the receiver the Viterbi MLSE is implemented to cancel noise and interference dueto the ltering and the channel. The BER against the SNR is analyzed in this thesis. The waterfallcurves are compared for two data rates of 1 M bps and 2 Mbps over both the Rayleigh and Rician fadingchannels.

  • 9.
    Ahmadi Mehri, Vida
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems.
    An Investigation of CPU utilization relationship between host and guests in a Cloud infrastructure2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Cloud computing stands as a revolution in IT world in recent years. This technology facilitates resource sharing by reducing hardware costs for business users and promises energy efficiency and better resource utilization to the service providers. CPU utilization is a key metric considered in resource management across clouds.

    The main goal of this thesis study is directed towards investigating CPU utilization behavior with regard to host and guest, which would help us in understanding the relationship between them. It is expected that perception of these relationships would be helpful in resource management.

    Working towards our goal, the methodology we adopted is experi- mental research. This involves experimental modeling, measurements and observations from the results. The experimental setup covers sev- eral complex scenarios including cloud and a standalone virtualization system. The results are further analyzed for a visual correlation.

    Results show that CPU utilization in cloud and virtualization sce- nario coincides. More experimental scenarios are designed based on the first observations. The obtaining results show the irregular behav- ior between PM and VM in variable workload.

    CPU utilization retrieved from both cloud and a standalone system is similar. 100% workload situations showed that CPU utilization is constant with no correlation co-efficient obtained. Lower workloads showed (more/less) correlation in most of the cases in our correlation analysis. It is expected that more number of iterations can possibly vary the output. Further analysis of these relationships for proper resource management techniques will be considered. 

  • 10.
    Ahmed, Atheeq
    Linköping University, Department of Electrical Engineering, Communication Systems.
    Human Detection Using Ultra Wideband Radar and Continuous Wave Radar2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A radar works by radiating electromagnetic energy and detecting the reflected signal returned from the target. The nature of the reflected signal provides information about the target’s distance or speed. In this thesis, we will be using a UWB radar and a CW radar to help detect the presence and rough location of trapped survivors by detecting their motions. Range is estimated in the UWB radar using clutter removal with SVD and for the dual frequency CW Radar using STFT and median filtering. The effect of the algorithm parameters on their performance was analyzed. The performance of the implemented algorithms with regards to small motion detection, distance estimation and penetration capability was analyzed. Both systems are certainly capable of human detection and tracking.

  • 11.
    Ahmed Mohamed Ahmed, Mazz
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Traffic Model Based Energy Efficient Radio Access Network2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    As the concerns about global energy consumption increased the matter of energy consumption in Radio Access Networks (RANs) became an important issue especially with the exponential growth in demanded traffic. This interest of developing innovative technologies to reduce the expected energy consumption by the mobile communication sector was driven by environmental concerns and cost reduction.

    The aim of this thesis is to introduce a new methodology to make the Radio Access Network (RAN) more energy efficient based on jointly the demanded throughput and a realistic traffic profile. Furthermore, to find a metric that quantifies the relation between the Energy Efficiency (EE), Spectrum Efficiency (SE) and demanded throughput.

    The proposed methodology for reducing the energy consumption in the RAN characterizes the offered throughput in order to determine the sufficient energy needed. The manner for reducing the energy consumed by the RAN is simply by switching (OFF/ON) Base Stations (BSs) based on the demanded throughput which introduces an energy efficient RAN.

    The results show a significant reduction in the energy consumption with regard to the demanded traffic. Moreover, it gives a measure of the EE with consideration to the SE which enhances the performance evaluation from an EE point of view during the RAN planning phase.

  • 12.
    Ahmed, Zubair
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    Design of Autonomous Low Power Sensor for Soil Moisture Measurement.2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Drought is the most severe disaster compared to other disasters in human civilization and their impacts are serious which can cause hungur, thrist, food shortages, loss of livestock directly effects the human life. The main objective of this project is to develop an early warning system (EWS) [3] for drought indices by using wireless sensor networks (WSNs) which is the only way forward for an on-site monitoring and validation of locally defined drought indices [3].The designed wireless sensor network (WSN) consisting of a sensor unit, a master unit and a sensor power management unit (PMU). The sensor unit measures the moisture of the soil and transmitt the measured data through ZigBee module to the master unit. A real time clock (RTC) is also used in the sensor unit which records the information of second, minute, hour, day, month of day and year about when or what time the measurement taken. The master unit consisting of a SD-card and Bluetooth module. SD-card is used to store measured data from other sensor units and it is possible to take out the reading of measured data from the master unit by accessing the SD-card via Bluetooth inside the master unit to a PC or a smartphone mobile.To manage the power in the sensor unit and to make sensor alive for several years, the power management unit (PMU) manages the power level between two energy storage buffers (i.e., a supercapacitor and a Li+ ion battery) for a sensor node.

  • 13.
    Ahmid, Abdel
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    More than downloading: Toward a scale with wireless connectivity2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Sensors are light-weight, low powered devices that measure some aspect of a physical or virtual environment and transmit this information in some format. This thesis describes how to integrate a sensor onto devices to enable network connectivity.

    The phrase “internet of things” suggests that within a few years many devices will be connected to an internet. Devices, including common household appliances, will transmit and receive data over a network. The CEO of Ericsson has stated that there will be more than 50 billion connected devices by 2020[1]. These devices could be microwaves, fridges, lights, or temperature sensors. Devices that are usually not associated with internet connectivity will be integrated into networks and play a larger role in providing information and controlling other devices. Sensors will have a major role in “the internet of things”. These small computers could be integrated in any appliances and transmit data over the network. The sensors’ low power and low cost, as well as their light weight, makes them very attractive to integrate them into many devices. The goal of this thesis project is to build upon this trend toward “The internet of things” by integrating a sensor into a bathroom scale thus enabling the scale to have networking connectivity. The sensor will be low cost and simple. It should wirelessly or via USB transmit the current weight that it measures to a receiver (specifically a gateway). This gateway will forward the message over the network to a website or mobile phone for visual presentation of the data. This thesis describes different techniques and approaches toward developing this sensor. The thesis also evaluates these different choices in order to select one technique that will be implemented. This solution will be evaluated in terms of its cost and ease of integration into an existing commercially produced scale.

  • 14.
    Ahola, David
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Yin To, Jie
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    To be entered/Green Cargo2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Schemakonstruktion för järnvägspersonal är en stor utmaning. En orsak är att arbetsuppgifterna vid järnvägen kräver olika kunskaps- och kompetenskrav, samt att det finns många arbetsregler som utgör restriktioner för schemakonstruktionen. I detta examensarbete har en fallstudie utförts för datorstödd schemakonstruktion för personalbemanning. Examensarbetet har utförts vid avdelningen för bemanningsplanering som ansvarar för planering av personal vid två av Green Cargos olika bangårdar. Huvudsyftet med det här examensarbetet är att utreda skillnaderna i scheman som skapats manuellt respektive automatiskt med hjälp av programvaran BP. Schemajämförelserna ska också redovisa nyttan av det automatiska planeringssättet där det finns applicerat. Under arbetet genomfördes litteraturstudier samt en fallstudie. I fallstudien genomfördes testkörningar med olika schemakonstruktionsmetoder på två bangårdar. Det numeriska resultatet visar att den datorassisterade bemanningsmetoden innebär en förbättrad bemanningsplanering ur företagets synvinkel då produktionsbehovet kan täckas utan ökade kostnader. Detta innebär också en ökad flexibilitet i produktionsplaneringen då tjänstgöringsturer enkelt kan ändras. Det gör det också mycket enklare att tilldela personal olika arbetsuppgifter som de har kompetens för. Den optimeringsbaserade bemanningsplanen innebär inte en ökad arbetsbelastning för medarbetaren. Trots att fler bangårdstjänster kan bemannas genom att använda den datorassisterade metoden visar det sig att den totala utlagda arbetstiden inte alls ökar eller att den bara ökar marginellt för vissa medarbetare. När planering sker med programvaran styrs denna av parametrar som är lätta att ändra. Dessa inställningar av parametrar är avgörande för utseendet på schemat. Indata kan vara fridagsplanering, kompetenstillgång och produktionsbehov. De i sin tur avgör i betydande grad på hur balansen mellan livs- och ekonomiska kvalitetsmåtten ser ut för medarbetarna.

  • 15.
    Al Rifai, Ahmad
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Indoor Positioning at Arlanda Airport2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Recent years have witnessed remarkable developements in wireless positioning systems to satisfy the need of the market for real-time services. At Arlanda airport in Stockholm, LFV - department of research and developement wanted to invest in an indoor positioning system to deliver services for customers at the correct time and correct place.

    In this thesis, three different technologies, WLAN, Bluetooth, and RFID and their combination are investigated for this purpose. Several approaches are considered and two searching algorithms are compared, namely Trilateration and RF fingerprinting. The proposed approaches should rely on an existing WLAN infrastructure which is already deployed at the airport. The performances of the different considered solutions in the aforementioned approaches are quantified by means of simulations.

    This thesis work has shown that RF fingerprinting provide more accurate results than Trilateration algorithm especially in indoor environments, and that infrastructures with a combination of WLAN and Bluetooth technologies result in lower average error if compared to infrastructures that adopt only WLAN.

  • 16.
    Al-Abaychi, Mustafa
    et al.
    KTH, School of Information and Communication Technology (ICT).
    Ellvin, Joanna
    KTH, School of Information and Communication Technology (ICT).
    Evaluation of VPNs2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis evaluated the performance of four different virtual private networks (VPNs): IP security (IPsec), OpenVPN, SSH port forwarding and SSH using virtual interfaces. To evaluate these VPNs, three comparative performance tests were carried out in which the maximum throughput of each VPN was measured. In every test, a specific parameter was varied to observe how it affected the VPNs throughput. The parameters varied were the type of transport layer protocol used, the encryption algorithm used and whether the VPN used compression or not. The results showed, among others, that when TCP traffic was transferred through the VPN and AES-128 was used as encryption algorithm in a Gigabit Ethernet network, the throughput for SSH port forwarding was 168 Mbit/s, 165 Mbit/s for IPsec, 95,0 Mbit/s for SSH using virtual interfaces and 83,3 Mbit/s for OpenVPN. These results are to be compared to the through put measured when no VPN was used, 940 Mbit/s. Three conclusions are drawn from the results of the performance tests. The first conclusion is that the throughput of a VPN depends on the technology the VPN solution is based on, the encryption method that is used and the type ofdata that is sent over the VPN. The second conclusion is that IPsec and SSH port forwarding are the most effective VPNs of the ones compared in this thesis, while OpenVPN and SSH using virtual interfaces are less effective. Lastly, it is concluded that although the different parameters affected the throughput of each VPN, the relation between the VPNs is the same in almost every test. In other words a VPN that performs well in one test performs well in every test.

  • 17.
    Albarrán Munoz, Isaac
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Parras Ruiz De Azúa, Manuel
    Telecommunication Services’ Migration to the Cloud: Network Performance analysis2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Nowadays, telecommunication services are commonly deployed in private networks, which are controlled and maintained by the telecommunication operators themselves, by co-location services providers, or, to some extent, by their hardware and software providers. However, with the present development of cloud computing resources, one might consider if these services could and should be implemented in the Cloud, thus taking advantage of cloud computing’s high availability, geographic distribution, and ease of usage. Additionally, this migration could reduce the telecommunication operators’ concerns in terms of hardware and network maintenance, leaving those to the Cloud computing providers who will need to supply a highly available and consistent service, to fulfill the telecommunication services’ requirements. Furthermore, virtualization provides the possibility of easily and rapidly changing the Cloud network topology facilitating the addition and removal of machines and services, allowing telecommunication services providers to adapt to their demands on the fly.

    The aim of this thesis project is to analyze and evaluate the level of performance, from the network point of view, that can be achieved when using Cloud computing resources to implement a telecommunication service, carrying out practical experiments both in laboratory and real environments. These measurements and analyses were conducted using an Ericsson prototype mobile switching center server (MSC-S) application, although the results obtained could be adapted to other applications with similar requirements.

    In order to potentially test this approach in a real environment, a prior providers’ survey was utilized to evaluate their services based on our requirements in terms of hardware and network characteristics, and thus select a suitable candidate environment for our purposes. One cloud provider was selected and its service was further evaluated based on the MSC-S application requirements. We report the results of our bench-marking process in this environment and compare them to the results of testing in a laboratory environment. The results of both sets of testing were well correlated and indicate potential for hosting telecommunication services in a Cloud environment, providing the Cloud meets the requirements imposed by the telecom services.

  • 18.
    Ali, Rahman
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    Design of Building Blocks in Digital Baseband Transceivers for Body-Coupled Communication2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Advances in communication technologies continue to increase information sharing among the people.~Short-range wireless networking technologies such as Bluetooth or ZigBee, which are mainly used for data transfer over short range, will, however, suffer from network congestion, high power consumption and security issues in the future.

    The body-coupled communication (BCC), a futuristic short-range wireless technology, uses the human body as a transmission medium. In BBC channel, a small electric field is induced onto the human body which enables the propagation of a signal between communication devices that are in the proximity or direct contact with the human body. The direct baseband transmission and simple architecture make BCC an attractive candidate for a future short-range wireless communication technology in particular applications such as body area network.

    The main focus of this thesis is on the design and implementation of digital baseband transmitter and receiver for the body-coupled communication. The physical layer (PHY) implementation of the digital baseband transmitter and receiver is inspired from the IEEE 802.3 Ethernet transmission protocol. The digital design is implemented at RTL level using hardware description language (VHDL). The functionality of the digital baseband transmitter and receiver is demonstrated by developing data transfer application layers.

  • 19.
    Ali Tandra, Sabrina
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Rizvi, S.M. Sarwarul Islam
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Security for Cloud Based Services2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Cloud computing is a new buzzword in the modern information technology world. Today cloud computing can be considered as a service, similar to the way that electricity is considered a service in urban areas. A cloud user can utilize different computing resources (e.g. network, storage, software application), whenever required, without being concerned with the complex underlying technology and infrastructure architecture. The most important feature is that the computing resources are available whenever they are needed. Additionally, users pay only for the resource they actually use. As a result, cloud users can easily scale their information technology infrastructure, based on their business policy and requirements. This scalability makes the business process more agile.

    The motivation for this thesis was the need for a suitable set of security guidelines for ifoodbag (and similar companies) when implementing web applications in the cloud. The goal of this thesis is to provide security in a system, being developed in another Master’s thesis project, to implement the ifoodbag web application in a cloud. To achieve this goal, we began by identifying the risks, threats, and vulnerabilities in the system model proposed by these other students for their implementation. A study was made of several different security mechanisms that might reduce or eliminate risks and secure the most vulnerable points in the proposed system’s design. Tests of these alternatives were conducted to select a set of mechanisms that could be applied to the proposed system’s design. Justification for why these specific mechanisms were selected is given. The tests allowed the evaluation of how each of these different security mechanisms affected the performance of the system. This thesis presents the test results and their analysis. From this analysis a set of mechanisms were identified that should be included in the prototype of the system. In conclusion, we found that DNSSEC, HTTPS, VPN, AES, Memcached with SASL authentication, and elliptic curve cryptography gave the most security, while minimizing the negative impact on the system. Additionally, client & server mutual authentication and a multi-level distributed database security policy were essential to provide the expected security and privacy that users would expect under the Swedish Data Protection law and other laws and regulations.

  • 20.
    Ali, Waqas Liaqat
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Securing Safebook: Secure Data Access Control and Key Management for Safebook2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Online social networks have become a fast and efficient way of sharing information and experiences. Over the past few years the trend of using social networks has drastically increased with an enormous amount of users’ private contents injected into the providers’ data centers. This has raised concerns about how the users’ contents are protected and how the privacy of users is preserved by the service providers. Moreover, current social networks have been subject to much criticism over their privacy settings and access control mechanism. The providers own the users’ contents and these contents are subject to potential misuse. Many socially engineered attacks have exposed user contents due to the lack of sufficient privacy and access control. These security and privacy threats are addressed by Project Safebook, a distributed peer-to-peer online social networking solution leveraging real life trust. By design Safebook decentralizes data storage and thus the control over user content is no longer in the service provider’s hands. Moreover, Safebook uses an anonymous routing technique to ensure communication privacy between different users.

    This thesis project addresses privacy aware data management for Safebook users and a data access control solution to preserve users’ data privacy and visibility utilizing a peer to peer paradigm. The solution focuses on three sub-problems: (1) preserving the user’s ownership of user data, (2) providing an access control scheme which supports fine grained access rights, and (3) secure key management. In our proposed system, the user profile is defined over a collection of small data artifacts. An artifact is the smallest logical entity of a profile. An artifact could be a user’s status tweak, text comment, photo album metadata, or multimedia contents. These artifacts are then logically arranged to form a hierarchical tree, call the User Profile Hierarchy. The root of the profile hierarchy is the only entry point exposed by Safebook from where the complete user profile can be traversed. The visibility of portions of the user profile can be defined by exposing a subset of profile hierarchy. This requires limiting access to child artifacts, by encrypting the connectivity information with specific access keys. Each artifact is associated with a dynamic access chain, which is an encrypted string and contains the information regarding the child nodes. A dynamic access chain is generated using a stream cipher, where each child’s unique identifier is encrypted with its specific access key and concatenated to form the dynamic access chain. The decryption process will reveal only those child artifacts whose access keys are shared. The access keys are managed in a hierarchical manner over the profile hierarchy. Child artifacts inherit the parent’s access key or their access key can be overridden with a new key. In this way, fine grained access rights can be achieved over a user’s artifacts. Remote users can detect changes in a specific branch of a profile hierarchy and fetch new artifacts through our proposed profile hierarchy update service. On top of the proposed access control scheme, any social networking abstraction (such as groups, circles, badges, etc.) can be easily implemented.

  • 21.
    Alisauskas, Saulius
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Community based testing2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Currently, Android is the most popular operating system for mobile devices, but at the same time, the market for Android devices is heavily fragmented in terms of available versions, types of devices, models, form-factors and manufactures. As a result, it is virtually impossible to test applications on all existing devices. Testing on a set of the most popular devices is more realistic but can be expensive, which makes it much more difficult for individual developers to create high quality applications.

    Fortunately, each Android application developer around the world typically owns at least one device which is not used all the time and could be shared with other developers. This way, a community shared pool of Android devices can be created for automated test execution.

    This master thesis reviews existing testing frameworks that are used for testing Android applications and analyzes existing services that in one way or another try to solve the problem of providing affordable ways of performing testing on real devices.  Main result of this thesis project is a working distributed community based testing service that enables developers to easily connect, share, and execute automated test cases on devices that use Android operating system. Moreover, it provides ways of decreasing overall test execution time by executing parts of tests in parallel on multiple devices and aggregating received results.

  • 22.
    Almkvist, Magnus
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Wahren, Marcus
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Preserving Integrity inTelecommunication Networks Opened bythe Parlay Service Interface2002Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This Master’s Thesis in Electrical Engineering concerns the introduction of a Parlay gateway in Skanova’s public circuit switched telephone network, what network integrity problems this brings, and how to preserve the integrity of the network.

    There is a rising demand from the market on Skanova to be able to offer integrated and useful services via their network. Examples of such services are Web Controlled Call Forwarding and Virtual Call Centres. Until now, these services have been implemented with the Intelligent Network concept which is a technology for concentrating the service logic in the telephone network to centralised service platforms within the network operator’s domain. Developing new services in this environment is expensive and therefore, Skanova wants to open the network for third party service providers. The opening of the network is enabled by the introduction of a gateway implementing the open service interface Parlay.

    The crucial point when opening the network for third party service providers is to maintain the integrity of the network. Parlay is an object oriented Application Programming Interface that enables a third party service access to core network resources in a controlled manner.

    The authors’ definition of network integrity is: “the ability of a network to steadily remain in a safe state, while performing according to the expectations and specifications of its owner, i.e. delivering the expected functionality and providing means to charge for utilised network resources”.

    The thesis describes a few services implemented via the Parlay interface and points out examples of activities in these services that may jeopardise the integrity of the network. The described activities belong to one of the two categories: Call Control Functionality or Lack of Charging Instruments.

    The thesis also describes two important methods for addressing encountered integrity problems. The methods are: Parlay Service Level Agreement and Policy Management.</p> Finally, the solutions are compared and the conclusion is that Policy Management is a conformable and flexible method for addressing lots of integrity problems and that these are important qualities, since new integrity problems will arise all the time.

  • 23.
    Al-Sheikhly, Yavor
    KTH, Superseded Departments, Teleinformatics.
    Implementing policy-based network management1999Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The aim of this thesis project is to help Ericsson implement policy-based network management. The department where the work is conducted is migrating to a new management platform, making it suitable to change the approach towards network management at the same time. An overview of the idea of policy based management will be given, together with suggestions on what is needed to successfully implement this strategy. Examples are presented on how to implement certain policies, given the new management platform. Finally, I present my conclusions of what is the proper path to a policy-based network management system for Ericsson’s internal use and describe future extensions.

  • 24.
    Altinkaya, Martin
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Ahmedi, Saman
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    SIP in an Interconnector and Service Provider Role2001Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This Master’s Thesis concerns the technical problems and solutions in the Telia Mobile’s Golden Gate Architecture. The Golden Gate project will bridge service control from the IPnetwork to the circuit switched network. Connecting the different users of PSTN, GSM, W-LAN, and GPRS networks together will require solutions to many problems. Most of the problems have already been defined by Telia. Our task is to evaluate two parts of the Golden Gate architecture, namely the Interconnect- and Service Provider roles.

    The Interconnector provider connects networks of different technical standards and enables other network operators to reach Service Providers on the Internet or other IP-based networks. The role concerns mainly mapping between SS7 signaling and the Session Initiation Protocol (SIP), charging and billing. Via the Interconnector the Service Provider can connect different services to any network.

    We will describe the SIP-protocol in detail and then we will look into the mapping between SS7 and SIP. We will also propose a charging model. It is important to have a solution that supports roaming between the different networks, we will evaluate such a solution. Most of the protocols (INAP, ENUM, MAP and ISUP) that are involved in the Golden Gate architecture are not completely defined. There are many Internet Drafts that discuss the possible functionality of the protocols and the interworking between them. Many different Internet-workgroups are working with these issues. No one seems to have the right answers for the interconnection between the protocols involved.

    Since the IP-telephony will probably replace today’s telephony systems, it is important to ensure a suitable Quality of Service (QoS), security that guarantees privacy, and a fair billing function. These are the three major problems in the IP-telephony world. IP-Telephony or Voice over IP (VoIP) has been on the market for a long time, there are many 'free IP-call sites' that use VoIP, but the quality of the calls are not yet good enough to replace traditional telephony. Our task here is to make sure that the necessary quality of service is provided, and a reliable charging model is used.

  • 25.
    Amso, Julian
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Faienza, Achille
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    IPsec Intrusion Detection Analysis: Using data from an Ericsson Ethernet Interface Board2008Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    IP security (IPsec) is commonly used for protection in Virtual Private Networks (VPN). It is also used for the protection of traffic between nodes in third generation (3G) mobile networks. The main duty of telecommunication operators is to assure the quality of service and availability of the network for their users. Therefore knowledge of threats that could affect these requirements is of relevance. Denial of Service (DoS) and other attacks could constitute serious threats in 3G networks and, if successful, they could lead to financial and reputation damage for the telecommunication operator. One of the goals of each telecommunications vendor is to produce equipment and software in such a way as to reduce the risk of successful attacks upon networks built using their equipment and software. This master’s thesis aims to identify the classes of attacks that could affect the regular operation of an IPsec-protected network. Therefore, the IPsec protocol and its possible weaknesses are explained. As practical demonstration of these ideas, an Intrusion Detection Analyzer prototype for an Ericsson Ethernet Interface board was developed to detect anomalous IPsec-protected traffic.

  • 26.
    Andersson, Dan
    KTH, School of Technology and Health (STH), Data- och elektroteknik.
    Implementation av prototyp för inomhuspositionering2013Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Development of technology constantly creates new opportunities but it can also mean major chang-es for companies and organizations. Today phones, tablets, laptops, mobile communications and cloud technology make it possible to be no longer bound by the time, location or device in order to work. The change means that a new office type that is more flexible and space efficient due to no fixed workplaces, is becoming more common. A problem with this type of offices that are known as flex-offices is that it is not obvious where or when a colleague is in the office, especially if it is large office with multiple floors.

    The aim of this work is to develop and implement a Location-Based Service for the company Connecta AB. The service will enable users to use their mobile phone to share their current workplace location in an office environment.

    The result of this work is a Location-Based Service that enables a user to use an Android phone with support for Near Field Communcication to share their current workplace position. The cloud-based server solution, Windows Azure is used to store indexed workplace positions.

  • 27. Andersson, Emma
    et al.
    Bröhne, Johan
    High Quality of Service in SDN: Bandwidth gurantee with QoS2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Video streaming through IP networks has risen rapidly over the recent years, and will continue to do so over the coming years. In addition to this, new technologies such as Virtual Reality and robotics will lead to many new applications that will put high pressure on the networks. To combat these challenges, networks need to be application sensitive, and be able to provide Quality of Service (QoS) based on requirement. Network paradigms like Software Defined Networking (SDN) enables the network to be directly programmable, and could thus solve the challenge. In this thesis, the objective is to research if SDN can provide High QoS.

    Methods are developed to achieve High QoS with SDN. A combination of Differentiated Services Code Point (DSCP) values and DSCP remarking with Meters are used enable High QoS and together they can give bandwidth guarantee. As a result of the thesis, a solid theoretical method is provided for achieving QoS, tests are performed and show that QoS can be implemented in SDN, but it is unable to implement High QoS due to the lack of implementation for Meters with DSCP remarking.

  • 28.
    Andersson, Johan
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Kleihs, Marcus
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Routing Interior2013Student paper second term, 5 credits / 7,5 HE creditsStudent thesis
    Abstract [sv]

    När datatrafik färdas genom ett nätverk så passerar det routrar och switcharsamtidigt som dessa enheter visar åt vilket håll paketet ska skickas. Detta kallas förrouting. För att paketen ska hitta rätt väg så använder man sig av routingprotokoll,som vägleder trafiken dit de ska, och olika protokoll har olika fördelar samtidigtsom de används vid olika tillfällen. Målet var att skapa ett stort enhetligt nätverksom tål höga belastningar, har en hög uppkopplingsprocent samtidigt som det skavara lätt att expandera i framtiden. Det största problemet var hur trafiken färdasmellan varje kontor, men problem som hur användarna ska vara uppkopplade tillInternet tas upp i rapporten. Nätverket använder sig av OSPF som routingprotokoll.Varje kontor delas in i områden, totallystubby area, vilket kortar nedroutingtabellen i Stockholm. Resultatet blir att snabba beslut tas när paket skaskickas inom ett kontor och när det ska utanför ett kontor så används en defaultroute. Samtidigt som kontoren är lätta att bygga ut då totallystubby area har endefault route till Stockholm.

  • 29.
    Andersson, Martin
    Linköping University, Department of Electrical Engineering, Information Coding.
    Parametric Prediction Model for Perceived Voice Quality in Secure VoIP2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    More and more sensitive information is communicated digitally and with thatcomes the demand for security and privacy on the services being used. An accurateQoS metric for these services are of interest both for the customer and theservice provider. This thesis has investigated the impact of different parameterson the perceived voice quality for encrypted VoIP using a PESQ score as referencevalue. Based on this investigation a parametric prediction model has been developedwhich outputs a R-value, comparable to that of the widely used E-modelfrom ITU. This thesis can further be seen as a template for how to construct modelsof other equipments or codecs than those evaluated here since they effect theresult but are hard to parametrise.

    The results of the investigation are consistent with previous studies regarding theimpact of packet loss, the impact of jitter is shown to be significant over 40 ms.The results from three different packetizers are presented which illustrates theneed to take such aspects into consideration when constructing a model to predictvoice quality. The model derived from the investigation performs well withno mean error and a standard deviation of the error of a mere 1:45 R-value unitswhen validated in conditions to be expected in GSM networks. When validatedagainst an emulated 3G network the standard deviation is even lower.v

  • 30.
    Andersson, Martin
    University of Skövde, School of Humanities and Informatics.
    SANDBUNKERSEGMENTERING FÖR SMARTPHONES: Automatisk positionsuppskattning av sandbunkrar för smartphone som golfcaddie2011Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Ett av många nya användningsområden för smartphones är att använda dem som

    caddie på golfbanan. Golfaren kan få hjälp med avståndsuppskattning till intressanta

    punkter på banan genom att dessa punkter programmeras in och jämförs med

    smartphonens inbyggda positioneringssystem. Den här rapporten visar hur det med en

    bildsegmenteringsalgoritm går att slippa det manuella arbetet med att lägga in

    positioner för sandbunkrar på golfbanan. Algoritmen som tagits fram arbetar på

    satellitbilder som smartphonen kan ladda ned via dess Internetanslutning. Golfaren

    kan i ett tänkt scenario ge sig ut på en godtycklig golfbana och få hjälp med

    avståndsbedömning enbart med hjälp av satellitbilder och smartphonens gps. I snitt

    hittar den framtagna segmenteringsalgoritmen cirka 70 % av sandbunkrarna på en

    satellitbild, en siffra som i en verklig applikation skulle behöva ökas och förslag på

    hur detta kan göras ges i slutet av rapporten. Tre olika upplösningar på satellitbilderna

    har utvärderats och testkörts i en nyare smartphone. Även om den högsta

    upplösningen används tar en hel golfbana endast cirka 15 sekunder att segmentera

    vilket bör hinnas med under loppet av en vanlig golfrunda som i regel tar 3 till 5

    timmar.

    I ett vidare perspektiv går det att tänka sig helt andra tillämpningar där det finns

    behov av positionsuppskattning av objekt i en satellitbild i sin smartphone. Det bör på

    ett förhållandevis enkelt sätt gå att utvidga slutsatserna som dragits i rapporten till att

    gälla annat än enbart sandbunkrar, t.ex. sjöar, fält, åkrar och givetvis andra delar av

    golfbanan som vattenhinder och greener.

  • 31.
    Andersson, Mattias
    et al.
    KTH, School of Information and Communication Technology (ICT).
    Dávila, Javier
    KTH, School of Information and Communication Technology (ICT).
    Energieffektiva byggmaterials påverkan på radiosignaler: Dämpning av radiosignaler i nya fastigheter2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The goal of this thesis is to examine the attenuation of new building materials on radio signals and the environmental effects that any signal improving solution might have.

    Environmental awareness and sustainable solutions are key issues when planning new buildings. Energy conservation and planning for the future puts pressure on companies to rethink the way they plan and construct new buildings.

    New materials and new techniques are required to reduce the amount of energy it takes to heat our buildings. One unfortunate drawback is the attenuation these new materials have on radio signals. This creates problems for the tenants as they are no longer able to use their mobile telephones indoors.

    To get around that problem a windows or door to the balcony is opened to get an acceptable reception. The energy losses that occur as a result are important to consider. A decrease in these energy losses might serve as an incentive for real estate owners to invest in signal improving solutions for their buildings.

    To get a better understanding of the problem, tests were performed in buildings that incorporate these new materials and techniques. The results of these tests were then used in mathematical models to analyze and to get a better understand the size of the problem. The results show a significant difference when compared to values used in previous calculations where 15dB was seen as a reasonable. This report suggest that the old value is changed to 23dB as seen in the analysis of the data collected. When this new value is used in the surface coverage models, the decrease in cell coverage from the base station becomes evident.

  • 32.
    Andersson, Tommy
    University of Skövde, School of Humanities and Informatics.
    Avvaktande AJAX- anrop: En avlastningsteknik för 3G-nätet2012Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Den ökade användningen av nätuppkopplade mobilapplikationer har resulterat i en överbelastning i 3G-nätet. Förslag för att avlasta nätet har bland annat varit genom alternativa uppkopplingar, vilket innebär en uppoffring av 3G-nätets tillgänglighet. Detta leder till frågor om andra avlastningsmetoder. Arbetets målsättning var att se hur en applikations datatrafik påverkas av att klassiska intervallanrop ersätts av avvaktande AJAX-anrop. Detta görs genom att implementera respektive anropsmetod i två identiska alfapetapplikationer. Mätdata erhölls genom att låta användare spela längre omgångar av respektive applikation, vilket även genererar realistiska uppdateringar. Resultaten visar att den klientgenererade bandbreddskonsumtionen minskas vid användning av avvaktande AJAX-anrop. Detta gör den, i kontrast med klassiska intervallanrop, till en möjlig avlastningsmetod.

  • 33.
    Andreasson, Carin
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Usability Studies of Wireless LAN Systems: *Design of the MUST – Method for Usability Studies and Tests*2001Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This document presents the thesis project “Usability Studies of Wireless Systems, Design of the MUST – Method for Usability Studies and Tests” that was part of the requirements for the degree of Master of Science in Electrical Engineering at the Royal Institute of Technology. The work was carried out at Ericsson WLAN Systems. They develop mobile enablers and had realized the importance of adding input, from the actual users of the systems, into the developing process. The problem was that Ericsson WLAN Systems did not have any kind of strategy for performing usability studies or user tests. The need for a method for usability studies initiated this thesis project.

    The method is called MUST (Method for Usability Studies and Tests) and directs itself towards a project leader and/or usability engineer. It interprets the indistinct and abstract declarations of usability into concrete tools for usability engineering. The method is applied alongside the ordinary development process to enable early and constant focus on usability and to structure the usability engineering. The MUST is divided into five different phases that form a lifecycle, describing the workflow when conducting usability engineering: Know the User, Setting Goals, Prototyping, Testing and User Feedback. Every phase within the MUST lifecycle has a specified goal to be achieved and methods to be used to achieve it. MUST also helps connecting the information flow from product management through software design to support.

    MUST has been tested in parts within this thesis project. Ericsson’s High Security System was put through a Thinking Aloud Test and new and interesting data was gathered through this test, revealing what the users really thought about the product as well as how they actually interacted with it. The results became valuable input to the up-grades of the High Security System.

  • 34.
    André, Johan
    KTH, Superseded Departments, Teleinformatics.
    Automated test procedure for GSM Over-The-Air SIM file management1999Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Developments of new Servers for Over-the-Air SIM file management and SIM Toolkit applications require a comprehensive test procedure to verify their operation. The goal of this Master Thesis has been to improve the existing test procedure and if possible develop a new procedure that could make the tests more efficient.

    Measurements showed that the most time consuming parts of the existing procedure were latencies in the GSM network and manual operations.

    Two major questions had to be handled if it was possible to fully automate the manual test procedure and if an application that reduced the latencies in GSM network would be efficient. This report indicates that it wasn't worth the effort to introduce such an automated test procedure since the extra workload was not in proportion to the benefits.

    In order to improve the performance due to the latencies in the GSM network an application that reduced this latency was implemented. This application made it possible to transfer Short Messages directly to the SIM-card without passing through the GSM network or through the mobile phone. With the new procedure the time for existing test procedure was reduced by as much as 65%.

  • 35.
    Angeles Piña, Carlos
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Distribution of Context Information using the Session Initiation Protocol (SIP)2008Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Context-aware applications are applications that exploit knowledge of the situation of the user (i.e. the user’s context) to adapt their behavior, thus helping the user achieve his or her daily tasks. Today, the transfer of context information needs to take place over unreliable and dynamically changing networks. Moreover context information may be produced in different devices connected to different networks. These difficulties have limited the development of context-aware applications. This thesis presents a context distribution method exploiting the event notification mechanisms of the Session Initiation Protocol (SIP), aiming to provide access to context information regardless of where it is produced.

    The context distribution component presented in this thesis uses SIP for Instant Messaging and Presence Leveraging Extensions (SIMPLE) to enable context sharing by using a SIP presence server, specifically the SIP Express Router (SER) and its presence module. This context distribution component allows distribution of context information in both synchronous and asynchronous mode. The distribution mode depends on the application requirements for context distribution, as well as the nature and characteristics of the contextinformation. In this thesis, based on system scalability, the user’s mobility, and latency - recommendations are given about in which situations each mode is more suitable for distributing context information.

    The system was evaluated using a load generator. The evaluation revealed that the server is highly scalable. The response time for synchronous retrieval of context information is nearly constant, while in asynchronous mode the time to process a subscription increases with the amount of information in the database regarding previous subscriptions. Notifications are sent at a regular rate (≈2800 notifications per second); however there is a purposely random delay (0 to 1 second), between an update of context information (i.e. receipt of a publish message) and the start of notifications to subscribed users.

    The requirements of the context-aware applications using the distribution component, such as response time, have to be taken into account when deciding upon the mode of context distribution for each application. This thesis provides some empirical data to help an application developer make this selection.

  • 36.
    Appelgren, Filiph
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Power System Software Development: with possible SCADA System Integration2014Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In order for power system operators (such as TRANSCO) to maintain and operatethe transmission grid in a safe, secure and effcient way, automatic tools such asSCADA systems is necessary to meet demand at all times. The main purpose of thisthesis was to develop a software/prototype at the load despatch centre at TRANSCOwith the ability to monitor and communicate with power plants. The software issupposed to work in a real-time electronic market. The power plant operators candeclare their availability and capability parameters of their generating and producingunits to TRANSCO and LDC operators can send load despatch instructions to thepower plants (such as load changes and other ancillary instructions). The prototypealso has a compliance monitoring application that validates unit outputs againstdespatched instructions. If the output is outside a specific interval, a transgressionwarning is sent to the power plant informing them that they should adjust their unitoutput against the target load. If further transgression is continued, the operator atLDC can re-declare the units availability on the power plants behalf and issue a newload despatch instruction to the unit. The re-declared availability level will be valid allthe way back to when the unit issued the last availability declaration.The software was successfully developed and could perform all tasks that it wassupposed to in a satisfactory way. In order to make the development as sufficient andeffective as possible, a "dummy" power plant was created and was used to simulateunit outputs and plant operator behaviour. As the time was too short, the SCADAintegration was never investigated and was left to whom is taken over after this thesishas ended.

  • 37.
    Arcos, Alejandro
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    A context-aware application offering map orientation2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this thesis context refers to information about the environment (the user or entity's surroundings) that can influence and determine the behavior of a computing system. Context-awareness means that the computer can adapt to the situation in which it is working. Context is a key issue in mobile computing, especially with handheld devices (such as PDAs and mobile phones), due to the fact that they can be used while on the move; hence the environment around them can change. The environment of a static device may also change and require the device to adapt. Applications and systems that exploit context by both sensing and reacting to their environment are called context-aware applications. Devices that are context-aware are able to perceive stimuli and react accordingly, with minimal interaction with the user.

    Providing context-aware services to users of mobile devices via context-aware applications is becoming an important and significant factor in the market and is a developing industry. In this thesis we analyze and develop an application that exploits context to provide a service that improves the interaction between humans and a computer. The thesis begins with a study of what types of sensors are available to provide information about the device's context. This is followed by the design of an appropriate way of using the selected sensor (ecompass) to provide a means of adapting a service to the user's and device's context. The focus is every day activities of a student at a university - specifically finding the location of a meeting room for a seminar; however, similar scenarios exist for other types of users.

    After determining that it was feasible to add a e-compass as a sensor to an existing personal digital assistant and to provide a map to the mobile user, the focus of the thesis shifted to an examination of the performance of the adaptation of the map as the user moved the device. Initially it required excessive time to render the map on the device, thus as the user moved the device the map was not updated quickly enough for the user to know their correct orientation with respect to the map. Therefore the thesis project examined how this performance could be improved sufficiently that the rendering would keep up with the change in orientation of the device. This investigation lead to a shift from server based rendering of the map as an image, followed by the transfer of the image to the device for display; to a sending a scalable vector graphics version of the map to the device for local rendering. While initially this was expected to be much faster than transferring an image for an actual map of the building where this work was taking place the local rendering was actually slower. This subsequently lead to server based pruning of the irrelevant details from the map, then a transfer of the relevant portion of the map to the device, followed by local rendering.

  • 38.
    Arefi Anbarani, Hossein
    KTH, Superseded Departments, Teleinformatics.
    ATM PON1998Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This document contains the final report of the thesis project: ATM based passive optical networks (ATM PONs). PONs are being tried as a method of extending optical fibres into the access network. PONs offer the ability of sharing the transmission costs of the access network amongst a large number of customers by allowing fibre and bandwidth sharing via passive optical splitters. ITU-T recommendation G.983 defines a specification for ATM based PONs. An SDL model was used in the project to investigate the possibility of using the Ericsson ATM switch (AXD 301) as the head-end in a G.983 compliant PON (i.e., the OLT). Also some simulations was made, using SDT. The results indicated that the ATM switch could very well serve as an OLT (by addition of a connection board). It was concluded that although the complexity of the system is quite high (caused by the TDMA technique used), it is a feasible solution. A techno-economical analysis made in the initial part of this project indicates that PONs are too expensive for deployment in the near future, compared to enhanced copper networks using xDSL technology. However, new applications could boost demand for high bandwidth sooner than expected. In any case, PONs (except in the FTTH configuration) constitute a natural upgrade for enhanced copper networks.

  • 39.
    Arguello Baltodano, Maria Jimena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Mesh-Relay with MRC in 802.16j Networks2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Multi-hop relay networks are a recent trend in WiMAX 802.16j networks. Many studies on the viability of relay stations have been done. It shows that RS are good cost-effective solution to the increasing demands on wireless broadband services. One problem that faces the 802.16j standard is its topology. It is a tree based multi-hop relay network, which is very vulnerable to single point breakage. This thesis proposes a new robust pairing technique in 802.16j network; combining a mesh topology with maximal ratio combining at the access link. Maximal ratio combining takes advantage of the broadcast nature of relay stations to obtain diversity gain. Mesh topology is a more robust topology without increasing delay or decreasing throughput. Maximal ratio combining provides higher throughput per burst, together a total throughput is increase 5% per frame is achieved.

  • 40.
    Aria, Erfan
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Investigation of automated vehicle effects on driver’s behavior and traffic performance2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Advanced Driver Assistance Systems (ADAS) offer the possibility of helping drivers to fulfill their driving tasks. Automated vehicles are capable of communicating with surrounding vehicles (V2V) and infrastructure (V2I) in order to collect and provide essential information about driving environment. Studies have proved that automated vehicles have a potential to decrease traffic congestion on road networks by reducing the time headway, enhancing the traffic capacity and improving the safety margins in car following. Furthermore, vehicle movement and driver’s behavior of conventional vehicles will be affected by the presence of automated vehicles in traffic networks. Despite different encouraging factors, automated driving raises some concerns such as possible loss of situation awareness, overreliance on automation and degrading driving skills in absence of practice. Moreover, coping with complex scenarios, such as merging at ramps and overtaking, in terms of interaction between automated vehicles and conventional vehicles need more research. This thesis work aims to investigate the effects of automated vehicles on driver’s behavior and traffic performance. A broad literature review in the area of driving simulators and psychological studies was performed to examine the automated vehicle effects on driver’s behavior. Findings from the literature survey, which has been served as setup values in the simulation study of the current work, reveal that the conventional vehicles, which are driving close to the platoon of automated vehicles with short time headway, tend to reduce their time headway and spend more time under their critical time headway. Additionally, driving highly automated vehicles is tedious in a long run, reduce situation awareness and can intensify driver drowsiness, exclusively in light traffic. In order to investigate the influences of automated vehicles on traffic performance, a microscopic simulation case study consisting of different penetration rates of automated vehicles (0, 50 and 100 percentages) was conducted in VISSIM software. The scenario network is a three-lane autobahn segment of 2.9 kilometers including an off-ramp, on-ramp and a roundabout with some surrounding urban roads. Outputs of the microscopic simulation in this study reveal that the positive effects of automated vehicles on roads are especially highlighted when the network is crowded (e.g. peak hours). This can definitely count as a constructive point for the future of road networks with higher demands. In details, average density of autobahn segment remarkably decreased by 8.09% during p.m. peak hours in scenario with automated vehicles. Besides, Smoother traffic flow with less queue in the weaving segment was observed. Result of the scenario with 50% share of automated vehicles moreover shows a feasible interaction between conventional vehicles and automated vehicles. Meaningful outputs of this case study, based on the input data from literature review, demonstrate the capability of VISSIM software to simulate the presence of automated vehicles in great extent, not only as an automated vehicle scenario but also a share of them, in traffic network. The validity of the output values nonetheless needs future research work on urban and rural roads with different traffic conditions.

  • 41.
    Arias, Jahaivis M.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Privacy in the context of Smart Home Environments: Based upon a survey of experts2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Smart environments, particularly smart homes have become an increasingly popular topic for research and real world implementations. Despite the popularity of this topic, there is a lack of tools to enable inhabitants of smart environments to perceive which kind of data smart devices generate and to make inhabitants aware of who is accessing their personal information and the purpose for accessing this information. These issues have caused privacy concerns among inhabitants of smart environments – who would like to ensure their personal information is only utilized for their benefits, rather than being used for malicious purposes. Therefore, smart home environments motivate the need for privacy awareness tools to help inhabitants to better understand the privacy implications when their personal information is misused. To address this problem, this thesis suggests guidelines for the design of privacy awareness tools.

    A literature review evaluated instruments to conduct research about privacy concerns. The Internet Users’ Information Privacy Concerns (IUIPC) framework from Malhotra, Kim, and Agarwal was selected for the empirical part of this thesis project because it is one of the most reliable models developed to measure privacy concerns at the individual level. Quantitative data was gathered through a survey based on this framework. Data collected from 30 experts in the field of study was analyzed using linear regression analysis techniques and principal component analysis.

    These survey results lead to a set of guidelines that could guide designers and service providers as to what aspects of privacy concerns they should consider and what they should concentrate on when designing privacy awareness tools for ubiquitous computing systems, such as a smart home.

  • 42.
    Arumugam Mathivanan, Arun
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    MiniSIP as a Plug-in2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Internet telephony has rapidly becoming an integral part of life. Due to its low incremental cost and the wide availability of voice over IP (VoIP) based services these services being used by nearly everyone. Today there are many VoIP applications available in the market, but most of them lack basic security features. Because people use VoIP services via public hotspots and shared local area networks these VoIP applications are vulnerable to attacks, such as eavesdropping. Today, there is a great need for VoIP applications with high quality security.

    MiniSIP is an open-source VoIP application platform, initially developed at KTH. High quality security has been a major focus of MiniSIP developments by several students, including the first public implementations of the secure real-time protocol (SRTP) and the Multimedia Key Exchange (MIKEY) protocol. MiniSIP implements secure end-to-end VoIP services. In addition, MiniSIP implements features such as dynamically choosing the most appropriate CODEC during a call, implementing calling policies, etc. However, it suffers from having a complicated GUI that requires the use of many libraries, rendering it both hard to build and hard support – both of which make it unsuitable for commercial purposes.

    Web browser plug-ins are shared libraries that users install to extend the functionality of their browser. For example, a plug-in can be used to display content that the browser itself cannot display natively. For example, Adobe's reader plugin displays PDF files directly within the web browser. Real Network’s Streaming video player utilizes a browser plug-in to provide support for live video streaming within a web page. Adobe’s Flash player plugin is required to load or view any Flash contents – such as video or animations.

    The goal of this thesis project is remove the problem of the existing MiniSIP GUIs by developing a Firefox browser plug-in for the MiniSIP application that will utilize a web-browser based GUI. The prototype that will be designed, implemented, and evaluated will implement an open-source VoIP application that is easy for a Firefox browser user to install and will be easy to use via a web interface. The long term goal is to facilitate an ordinary user to utilize VoIP communication via their web browser. A secondary goal is to re-use the code within MiniSIP, while using the web-browser to provide the GUI.

  • 43.
    Arvidsson, Simon
    et al.
    Linköping University, Department of Computer and Information Science.
    Ekblom, Tobias
    Linköping University, Department of Computer and Information Science.
    Marknadsplatsapplikation för Android2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Målet med examensarbetet är att utveckla en marknadsplatsapplikation för Android. Marknadsplatsapplikationen ska tillhandahålla funktioner för att ge användaren förutsättningar att hitta och ladda ner applikationer över Internet ifrån marknadsplatsens serversida. Marknadsplatsapplikationen kommer likt en tunn klient vara helt beroende av innehåll från en serversida. Vid examensarbetets utförande existerade dock ingen serversida då denna ännu inte var färdigutvecklad.

    För att utveckla marknadsplatsapplikationen utan närvaron av en serversida, implementerades en emulerad serversida som utåt sett hade funktionaliteten av en framtida serversida. En mjukvaruarkitektur implementerades bestående av tre lager: användargränsnitt (GUI), kärnfunktionalitet (Core) och webbkommunikation (WebCom). Syftet med arikitekturen var dels att begränsa inverkan av övergången från en emulerad serversida till en riktig serversida, och dels att avgränsa och avlasta användargränsnittet från tunga operationer för att därigenom uppnå god responsivitet.

    Marknadsplatsapplikationen implementerades med all funktionalitet som planerades. Arkitekturen med tydlig separation mellan GUI, Core ochWebCom, förväntas leda till en smidig övergång till en riktig serversida. Även ett tydligt öde för att hämta och skicka data mellan marknadsplatsapplikationen och serversida förväntas underlätta att implementera ny funktionalitet som är beroende av en serversida. Användargränsnittet uppvisar fortfarande brist på responsivitet. Arkitekturen med endast en asynkron klass GuiWorker, som hanterar exekveringen av tunga operationer på bakgrundstrådar, förväntas dock kunna uppnå ett responsivt användargränsnitt.

  • 44.
    Aspnäs, Frida
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Eliminating Right-Turn-on-Red (RTOR) at Key Intersections in a City Core2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The City of Fredericton is the capital of New Brunswick, located in eastern Canada. Rightturn-on-red (RTOR) is a general practice at any traffic intersection in this maritime province. Many collisions between pedestrians and vehicles have been recorded at signalized intersections in the downtown area of the city. Due to the number of collisions, the City of Fredericton was interested in investigating how a restriction against RTOR could affect vehicular traffic. The purpose and goal of this project was to develop a calibrated traffic model of the downtown area of Fredericton that could be used for simulation studies. Two main changes were investigated: 1) a restriction against RTOR for each of eleven key intersections in the downtown area, and 2) a restriction against left-turns at one selected intersection. The traffic simulation model was also used for analyzing how factors such as pedestrian volumes, lane channelization, and turning proportions affect the changes in traffic conditions due to permitting, or prohibiting, right-turn-on-red.

    The traffic simulation model was created in the TSIS/CORSIM software. Several different scenarios were generated for analysis. The results of the simulation show that the traffic conditions in the whole downtown area will be affected when introducing a restriction against RTOR. Certain intersections show a relatively high change while others show no significant change at all. Several different factors were seen to affect the number of RTOR that could be performed at an intersection. One main factor was lane channelization. With a shared lane, the proportion of right-turning vehicles at the intersection was found to highly affect how many RTOR can be performed. Pedestrian volumes prove to be a third factor affecting the number of RTOR at an intersection.

    Overall results demonstrate that there are only a few intersections where it is suitable for the City of Fredericton to implement a restriction against RTOR.

  • 45.
    Atiiq, Syafiq Al
    KTH, School of Electrical Engineering (EES), Network and Systems engineering.
    Adaptive Counteraction Against Denial of Service Attack2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The Internet of Things (IoT) is the next generation of networked society where billions of, everyday-life, devices are directly connected to the Internet and able to communicate with each other. In particular, the Constrained Application Protocol (CoAP) has become the de-facto IoT standard for communication at the application layer, as a lightweight web transfer protocol affordable also for resource-constrained platforms. However, as IoT devices are directly connected to the Internet, they are especially vulnerable to a number of security attacks including Denial of Service (DoS), which can seriously worsen their performance and responsiveness, and even make them totally unavailable to serve legitimate requests.

    In this Master's Thesis project, we have developed a cross-layer and context-aware approach that adaptively counteracts DoS attacks against CoAP server devices, by dynamically adjusting their operative state according to the attack intensity. This considerably limits the impact of DoS attacks and preserves service availability of victim devices to the best possible extent. The proposed approach leverages a trusted Proxy that adaptively shields victim devices, while effectively forwarding and caching messages if needed. We have made a proof-of-concept implementation of our solution for the Californium framework and the CoAP protocol, and experimentally evaluated its effectiveness in counteracting DoS and preserving availability of devices under attack.

    This Master's Thesis project has been conducted in collaboration with RISE SICS, a research institute for applied information and communication technology in Sweden.

  • 46.
    Avesand (nee Sjöquist), Stefan
    KTH, Superseded Departments, Teleinformatics. KTH, School of Information and Communication Technology (ICT).
    Secure Database Access in Java Applets1998Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    For many years the web has only been used as a way ofdistributing information, but the need for more interaction isgrowing stronger. To accomplish this one can use Javaapplets, HTML forms, Active X, Javascript and a few othertechniques. One problem is that you must store the data theusers create, and change, somewhere and somehow. As thetitle reveals, this thesis will analyze a few ways to do this inJava applets.

  • 47.
    Avgeropoulos, Konstantinos
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Service Policy Management for User-Centric Services in Heterogeneous Mobile Networks,2004Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The Session Initiation Protocol (SIP) is a signaling protocol for IP-based media services that will be the de facto standard for future media-over-IP services. Since SIP User Agents (UAs) support a limited number of service types (usually one or two), we assume that the future user will need to operate several UAs simultaneously. These UAs will constitute the user's personal service network. In this thesis, we investigate architectures for policy-based management of this network so that it can be used in an efficient manner. To achieve this, we propose a new SIP entity, called the SIP Service Manager (SSM), which lies in the core of the management system. Finally, we evaluate our proposal by implementing one version of the SIP Service Manager.

  • 48.
    Axelsson, Andreas
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Ambrosius, Christian
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Nya lagar och avtal: Hur kan de komma att förändra svenskarnas fildelningsvanor?2012Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [sv]

    I många år nu har det varit vanligt förekommande att människor suttit hemma vid sin dator och med några få klick laddat ner filmer, musik och programvaror, till en början helt lagligt, men med åren har lagar kommit till som har gjort det mer och mer olagligt.Oavsett om det har varit lagligt eller inte, så är det troligt att många artister, filmmakare och liknande gått miste om stora summor pengar i förlorade inkomster på grund av att folk inte har betalat för att ta del av deras verk, utan istället valt att ladda ner dem över Internet.

    Det faktum att fildelning har blivit så pass vanligt och att folk inte har sett det som ett särskilt allvarligt brott, har lett till att fildelning länge har varit ett hett omdiskuterat ämne i media, bland upphovsrättsinnehavare och bland folk i allmänhet. Upphovsmän och upphovsrättsinnehavare, såsom filmbolag, författare och artister har legat på och debatterat för att försöka få till en hårdare lagstiftning för att försvåra fildelning och kopiering av upphovsrättsskyddat material, samt för att få till hårdare straff mot fildelning.

    Flera försök från beslutsfattare har gjorts för att råda bot på problemet, nya lagar har stiftats och avtal har skrivits under. Frågan är om de nya lagarna och avtalen gör någon nytta? Blir folk avskräckta från att fildela eller fortsätter de som förut? Många har säkert under många år blivit bortskämda med att kunna sitta hemma vid datorn och på några minuter få hem de senaste filmerna och den nyaste musiken helt gratis, vilket säkert gör det svårt att helt plötsligt sluta fildela och börja betala för film och musik igen.

  • 49.
    Axelsson, Johannes
    Linnaeus University, Faculty of Technology, Kalmar Maritime Academy.
    WAN-optimering för sjöfarten: En möjlighet att effektivisera datakommunikationen till sjöss2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Shipboard operations have become more reliant of data communication and many of the duties on board may be facilitated if the crew can access information stored elsewhere. The broadband connection between ship and shore is mostly done via satellite communication where long distances and limited data rate results in inefficient data communication. This study examines network optimization and the performance improvement this can have regarding slow WAN connections via satellite. The survey showed that the biggest issue with data communication via satellite is the signal delay caused by the long transmission distance which means that there will be performance degradation for data traffic and users will experience the data communication as slow. To solve this there is equipment that enhances the performance of the connection and handles the data communication by implementing various techniques. To investigate how much the performance improvement can be this study carried out a number of experiments with network optimization equipment.  The experiments evaluated file transfer with and without network optimization. The results show that the network optimization gives a major performance improvement regarding file transfer.

  • 50.
    Ayrault, Cécile
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Service discovery for Personal Area Networks2004Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    With the increasing use of electronic devices, the need for affordable wireless services specifically context-aware services, in a so-called Personal Area Network (PAN) is becoming an area with significant potential. Service discovery is a basic function.

    Even though a number of service discovery protocols have been implemented, a specific protocol for a PAN environment may need to be developed, as the characteristics of a PANs differ from other networking environments. Thus, the specific requirements for service discovery from a PAN perspective were studied. Methods for service discovery will be described that take into account both local and remote services.

    These methods will then be evaluated in a SIP telephony infrastructure to decide where a call should be delivered. The location of a person is done by using the implemented service discovery.

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