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  • 101.
    Atla, Prashant
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Power Profiling of different Heterogeneous Computers2017Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Context: In the present world, there is an increase in the usage of com- munication services. The growth in the usage and services relying on the communication network has brought in the increase in energy consumption for all the resources involved like computers and other networking compo- nent. Energy consumption has become an other efficient metric, so there is a need of efficient networking services in various fields which can be obtained by using the efficient networking components like computers. For that pur- pose we have to know about the energy usage behavior of that component. Similarly as there is a growth in use of large data-centers there is a huge requirement of computation resources. So for an efficient use of these re- sources we need the measurement of each component of the system and its contribution towards the total power consumption of the system. This can be achieved by power profiling of different heterogeneous computers for es- timating and optimizing the usage of the resources.

    Objectives: In this study, we investigate the power profiles of different heterogeneous computers, under each system component level by using a predefined workload. The total power consumption of each system compo- nent is measured and evaluated using the open energy monitor(OEM). Methods: In oder to perform the power profile an experimental test bed is implemented. Experiments with different workload on each component are conducted on all the computers. The power for all the system under test is measured by using the OEM which is connected to each system under test(SUT).

    Results: From the results obtained, the Power profiles of different SUT’s are tabulated and analyzed. The power profiles are done in component level under different workload scenarios for four different heterogeneous comput- ers. From the results and analysis it can be stated that there is a variation in power consumed by each component of a computer based on its con- figuration. From the results we evaluate the property of super positioning principle. 

  • 102.
    Atuyota-Ejughemre, Kesiena
    Blekinge Tekniska Högskola, Sektionen för management.
    Promoting Mobile Financial Transactions: A Case Study Zain Sierra Leone2009Självständigt arbete på avancerad nivå (magisterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Title – Promoting Mobile Financial Transactions: A Case study of Zain Sierra Leone Author – Kesiena Atuyota-Ejughemre Supervisor - Anders Hederstierna Department: School of Management, Blekinge Institute of Technology Course: Master’s thesis in business administration, 15 credits (ECTS). Background and Problem Discussion: There are challenges associated with overly cash based societies. The use of mobile financial systems could address some of these challenges. Understanding the factors that influence people’s willingness to use mobile systems for financial transactions could be significant in developing strategies to transition from traditional payment systems to mobile financial transaction systems. Purpose – The purpose of this is to assess contribution of customer trust and perception of customer focus to the willingness of GSM subscribers to use the mobile system for financial transactions and how the understanding derived from these factors can be used to develop strategies to promote a transition from cashed based society to mobile financial transactions. Method- Quantitative and deductive approach was used. 300 GSM respondents who were selected with a multistage sampling method in three locations were surveyed. Interviewers were used to get data on perceived customer focus level, customer trust and willingness to engage in mobile financial transactions. Theory – Theory section looks at the concepts relating to customer trust and customer perception of customer focus and pertinent subconstructs applicable to the engagement in mobile financial transactions. Analysis – I have used correlational analysis to verify the level of association between customer trust, customer focus perception, socio demographic factors and the willingness to engage in mobile financial transactions. In order to verify the influence of income, a non parametric test was done. Conclusions – The analysis of the data results showed that there is a strong positive association between the willingness to use mobile for financial transactions. Also, the analysis revealed a positive correlation between the perception of customer focus by subscribers and the willingness to engage in mobile financial transactions. There was no significant influence by demographic factors such as age and gender on the willingness to engage in mobile financial transactions. A 3 phased implementation strategy was proposed for the deployment of a mobile financial transaction system.

  • 103.
    Awan, Zafar Iqbal
    et al.
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för telekommunikationssystem.
    Azim, Abdul
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för telekommunikationssystem.
    Network Emulation, Pattern Based Traffic Shaping and KauNET Evaluation2008Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Quality of Service is major factor for a successful business in modern and future network services. A minimum level of services is assured indulging quality of Experience for modern real time communication introducing user satisfaction with perceived service quality. Traffic engineering can be applied to provide better services to maintain or enhance user satisfaction through reactive and preventive traffic control mechanisms. Preventive traffic control can be more effective to manage the network resources through admission control, scheduling, policing and traffic shaping mechanisms maintaining a minimum level before it get worse and affect user perception. Accuracy, dynamicity, uniformity and reproducibility are objectives of vast research in network traffic. Real time tests, simulation and network emulation are applied to test uniformity, accuracy, reproducibility and dynamicity. Network Emulation is performed over experimental network to test real time application, protocol and traffic parameters. DummyNet is a network emulator and traffic shaper which allows nondeterministic placement of packet losses, delays and bandwidth changes. KauNet shaper is a network emulator which creates traffic patterns and applies these patterns for exact deterministic placement of bit-errors, packet losses, delay changes and bandwidth changes. An evaluation of KauNet with different patterns for packet losses, delay changes and bandwidth changes on emulated environment is part of this work. The main motivation for this work is to check the possibility to delay and drop the packets of a transfer/session in the same way as it has happened before (during the observation period). This goal is achieved to some extent using KauNet but some issues with pattern repetitions are still needed to be solved to get better results. The idea of history and trace-based traffic shaping using KauNet is given to make this possibility a reality.

  • 104.
    AWONIYI, OLUWASEYI
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för signalbehandling.
    STRATOSHPHERIC CHANNEL MODELLING2007Självständigt arbete på avancerad nivå (magisterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    High Altitude Platform Stations (HAPs) are communication facilities situated at an altitude of 17 to 30 km and at a specified, nominal, fixed point relative to the Earth. They are mostly solar-powered, unmanned, and remotely-operated. These platforms have the capability of carrying multipurpose communications relay payload, which could be in the form of full base station or, in some cases, a simple transponder as is being used in satellite communication systems. HAPs, when fully deployed will have the capability of providing services and applications ranging from broadband wireless access, navigation and positioning systems, remote-sensing and weather observation/monitoring systems, future generation mobile telephony etc. HAPs are also known to be low cost when it comes to its implementation and are expected to be the next big provider of infrastructure for wireless communications. There have been a lot of ongoing and exciting research works into various aspects of this emergent technology. As radio Engineers, the need to predict the channel quality and analyze the performance evaluation of such stratospheric propagation has generated quite a few models. Although some of the models under consideration are from the existing terrestrial and satellite communications which in some way, have some relationships with this new technology. This thesis work provides some insight into this new aspect of wireless communications in terms of the need for a new system, its benefits, challenges services provided and applications supported. Existing models already researched and developed for HAPS are reviewed; one of them was picked and deeply looked into as regards the propagation and channel efficiency. The analysis of the choice model is presented using one of the performance test for channel models, the bit error rate (BER).

  • 105.
    Axelsson, Arvid
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för datalogi och datorsystemteknik.
    Light Field Coding Using Panoramic Projection2014Studentuppsats (Examensarbete)
    Abstract [sv]

    Nya tekniker är under utveckling för 3D-bildskärmar kan visa light field: bilder och video som spelas in med arrayer av kameror. Sådan video kräver stora datamängder. En ny kodning av light field, syftande till att uppnå ett bättre förhållande mellan bildkvalitet och bitrate, utvärderas i det här examensarbetet.

  • 106.
    Ayichiluhm, Theodros
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Mohan, Vivek
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    IPv6 Monitoring and Flow Detection2013Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    IPv6 Privacy extensions, implemented in major operating systems, hide user’s identity by using a temporary and a randomly generated IPv6 addresses rather than using the former, EUI-64 format where the MAC address is part of the IPv6 address. This solution for privacy has created a problem for network administrators to back-trace an IPv6 address to a specific MAC address, since the temporary IP address used once by the node is removed from the interface after a period of time. An IPv6 Ethernet test bed is setup to investigate IPv6 implementation dynamics in Windows 7 and Ubuntu10.04 operating systems. The testbed is extended to investigate the effects of temporary IPv6 addresses due to IPv6 privacy extensions on the on-going sessions of different applications including ping, File Transfer Protocol (FTP) and video streaming (HTTP and RTP). On the basis of the knowledge obtained from investigations about dynamics of IPv6 privacy extensions, this work proposes Internet Protocol version 6 Host Tracking (IPv6HoT), a web based IPv6 to MAC mapping solution. IPv6HoT uses Simple Network Management Protocol (SNMP) to forward IPv6 Neighbor table from routers to Network Management Stations (NMS). This thesis work provides guidelines for configuring IPv6 privacy extensions in Ubuntu10.04 and Windows 7; the difference of implementation between these two operating systems is also presented in this work. The results show that temporary IPv6 addressing has a definite effect on the on-going sessions of video streaming and FTP applications. Applications running as server on Temporary IPv6 address encountered more frequent on-going session interruptions than applications running as a server over public IPv6 address. When temporary IPv6 addresses were configured to host FTP and video streaming applications, their on-going sessions were permanently interrupted. It is also observed that LFTP, a client FTP application, resumes an interrupted session.

  • 107.
    Ayub, Hasan
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Awan, Shoaib Shafiq
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    QoS and Integrating issues of Real Time Traffic within Wireless Environment2009Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Wireless technology in simple words is a technique that enables more than one user to share resources without having wiring. In comparison with wired local area network in which twisted pair cables, adapters and coaxial cables are used to connect multiple devices. Wireless technology has enabled us to send and receive data through radio and infrared waves and a single access point in WLAN can easily accommodate many users in the same domain. In this era of technology we want everything to be simplified to the maximum and in regards to wireless technology we want to have voice over IP instead of analog phones this is what we call real time traffic. In this Thesis report we have studied the WLAN technology in detail with special emphasis on QoS issues and tried to suggest the possibilities on how to integrate real time traffic on WLAN. Through simulation we will try to find improvements in this field. Our main focus will be on CSMA/CA protocol of 802.11 and 802.11e standards, and different MAC schemes that are used to accommodate different types of traffic, special emphasis is given on DCF and EDCA. Through simulation we will show the results that how these fields can affect the QoS of WLAN, these schemes enables more user capacity which means that we can increase the traffic and make wireless LAN more adaptive. The simulation that we will do in this Thesis will be totally correlated with our research but it will not be practically implemented.

  • 108.
    Azam, Adnan
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Siddique, Taimoor
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Spectrum Optimization in Cognitive Radio Networks using Genetic Algorithms2010Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [sv]

    Den snabba revolution inom trådlös kommunikation under de senaste åren har ökat efterfrågan av radiospektrum för att fullgöra tjänsternas kvalitet (QoS) för trådlösa tillämpningar, vilket leder till spektrum överbeläggning. För att lösa spektrum överbeläggning problemet, kognitiv radio (CR) har trätt fram som en ledande teknik, eftersom det kan intelligent mening en oanvänd spektrum utan att skapa någon skada för behöriga användare. När spektrum anade att uppfylla QoS krav på ansökan och att använda radion resurserna mer effektivt, ett intelligent beslut om att tilldela en optimal spektrum är ett bra krav. I det här examensarbetet en spektrumallokering förfarande föreslås. Genetiska algoritmer (GA) en evolutionär datoriserad teknik används som arbetar Darwins evolutionsteori. Den definierar radio i form av kromosomer och gener. Förfarandet modelleras med hjälp av Matlab, och programmets QoS krav har uppställts som underlag till GA förfarandet, vilket resulterar i en optimal lösning efter flera evolution

  • 109.
    Azam, Muhammad
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Methods for Recovery of Missing Speech Packets2011Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [sv]

    Denna magisteravhandling beskriver två metoder för återskapande av förlorade talpaket, samt rekonstruktion av talsignal då ett fåtal signalsampel saknas. Därtill föreslår avhandlingen utökningar till dessa två metoder för att hantera två efterföljande saknade talpaket. Metoderna är presenterade och utvärderade på talsignaler där signalvärden har förstörts enligt en given kanalmodell.

  • 110.
    Aziz, Md. Tariq
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Islam, Mohammad Saiful
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Performance Evaluation of Real–Time Applications over DiffServ/MPLS in IPv4/IPv6 Networks2011Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Over the last years, we have witnessed a rapid deployment of real-time applications on the Internet as well as many research works about Quality of Service (QoS) in particularly IPv4 (Internet Protocol version 4). The inevitable exhaustion of the remaining IPv4 address pool has become progressively evident. As the evolution of Internet Protocol (IP) continues, the deployment of IPv6 QoS is underway. Today, there is limited experience in the deployment of QoS for IPv6 traffic in MPLS backbone networks in conjunction with DiffServ (Differentiated Services) support. DiffServ itself does not have the ability to control the traffic which has been taken for end-to-end path while a number of links of the path are congested. In contrast, MPLS Traffic Engineering (TE) is accomplished to control the traffic and can set up end-to-end routing path before data has been forwarded. From the evolution of IPv4 QoS solutions, we know that the integration of DiffServ and MPLS TE satisfies the guaranteed QoS requirement for real-time applications. This thesis presents a QoS performance study of real-time applications such as voice and video conferencing over DiffServ with or without MPLS TE in IPv4/IPv6 networks using Optimized Network Engineering Tool (OPNET). This thesis also studies the interaction of Expedited Forwarding (EF), Assured Forwarding (AF) traffic aggregation, link congestion, as well as the effect of various performance metrics such as packet end-to-end delay, packet delay variation, queuing delay, throughput and packet loss. The effectiveness of DiffServ and MPLS TE integration in IPv4/IPv6 network is illustrated and analyzed. The thesis shows that IPv6 experiences more delay and loss performance than their IPv4 counterparts.

  • 111.
    AZIZ, YASSAR
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för matematik och naturvetenskap.
    ASLAM, MUHAMMAD NAEEM
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för matematik och naturvetenskap.
    Traffic Engineering with Multi-Protocol Label Switching, Performance Comparison with IP networks2008Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Traffic Engineering (TE) is the stage which deals with geometric design planning and traffic operation of networks, network devices and relationship of routers for the transportation of data. TE is that feature of network engineering which concentrate on problems of performance optimization of operational networks. It involves techniques and application of knowledge to gain performance objectives, which includes movement of data through network, reliability, planning of network capacity and efficient use of network resources. This thesis addresses the problems of traffic engineering and suggests a solution by using the concept of Multi-Protocol Label Switching (MPLS). We have done simulation in Matlab environment to compare the performance of MPLS against the IP network in a simulated environment. MPLS is a modern technique for forwarding network data. It broadens routing according to path controlling and packet forwarding. In this thesis MPLS is computed on the basis of its performance, efficiency for sending data from source to destination. A MATLAB based simulation tool is developed to compare MPLS with IP network in a simulated environment. The results show the performance of MPLS network in comparison of IP network.

  • 112. Badoi, Cornelia-Ionela
    et al.
    Croitoru, Victor
    Popescu, Adrian
    IPSAG Cognitive Radio Routing Protocol: Models and Performance2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    The paper is about performance evaluation of IP Spectrum Aware Geographic routing protocol (IPSAG). IPSAG is an opportunistic cognitive routing protocol which determines a source-destination route in a hop by hop manner, based on both global and local information. Simulation results are reported for a particular case of IPSAG, where the cognitive radio (CR) nodes are uniformly distributed inside the cognitive radio network (CRN), and a two-dimensional random walk model is used to model the mobility of CR nodes. The results show that the IPSAG protocol is performing well in the case of a highly mobile CRN and that the source-destination path is successfully found in the majority of the cases, especially when the network is highly populated.

  • 113.
    Bahrieh, Sara
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Sensor Central / Automotive Systems2013Självständigt arbete på grundnivå (kandidatexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    How to display objects which were detected from different devices in one coordinate system? Nowadays most vehicles are equipped with front and back sensors to help the driver in driving process. Companies who provide this technology need to have an application which enables them for easy data fusion from these sensors and recording the process. Besides sensor’s design, programming of them is an important aspect. BASELABS Connect has the solution in a user friendly way. Creating Sensor Central component for BASELABS Connect is the main goal of this thesis. Sensor Central from BASELABS Connect requires six variables of sensor’s position for each sensor to demonstrate the objects from all sensors to one unique coordinate system. In this thesis, it was intended to create such a component which was mounted between all the sensors and the charting component to convert the objects location from different sensor’s position to one coordinate system and to be usable from other vehicles too.

  • 114.
    BAIG, CLEMENT RANJITH ANTHIKKAD & IRFAN AHMED
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    PERFORMANCE ENHANCEMENT OF OFDM IN PAPR REDUCTION USING NEW COMPANDING TRANSFORM AND ADAPTIVE AC EXTENSION ALGORITHM FOR NEXT GENERATION NETWORKSPERFORMANCE ENHANCEMENT OF OFDM IN PAPR REDUCTION USING NEW COMPANDING TRANSFORM AND ADAPTIVE AC EXTENSION ALGORITHM FOR NEXT GENERATION NETWORKS2013Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [sv]

    The proposed technique namely Adaptive Active Constellation Extension (Adaptive ACE) Algorithm reduced the high Peak-to-Average Power Ratio (PAPR) of the Orthogonal Frequency Division Multiplexing (OFDM) systems. The Peak-to-Average Power Ratio (PAPR) is equal to 6.8 dB for the target clipping ratios of 4 dB, 2 dB and 0 dB by using Adaptive Active Constellation Extension (Adaptive ACE) Algorithm. Thus, the minimum PAPR can be achieved for low target clipping ratios. The Signal-to-Noise Ratio (SNR) of the Orthogonal Frequency Division Multiplexing (OFDM) signal obtained by the Adaptive Active Constellation Extension (Adaptive ACE) algorithm is equal to 1.2 dB at a Bit Error Rate (BER) of 10-0..4 for different constellation orders like 4-Quadrature Amplitude Modulation (4-QAM), 16-Quadrature Amplitude Modulation (16-QAM) and 64-Quadrature Amplitude Modulation (16-QAM). Here, the Bit Error Rate of 10-0.4 or 0.398, that means a total of 398-bits are in error when 1000-bits are transmitted via a communication channel or approximately 4-bits are in error when 10-bits are transmitted via a communication channel, which is high when compared to that of the original Orthogonal Frequency Division Multiplexing (OFDM) signal. The other problems faced by the Adaptive Active Constellation Extension (Adaptive ACE) algorithm are Out-of-Band Interference (OBI) and peak regrowth. Here, the Out-of-Band Interference (OBI) is a form of noise or an unwanted signal, which is caused when the original Orthogonal Frequency Division Multiplexing (OFDM) signal is clipped for reducing the peak signals which are outside of the predetermined area and the peak regrowth is obtained after filtering the clipped signal. The peak regrowth results to, increase in the computational time and computational complexity. In this paper, we have proposed a PAPR reduction scheme to improve the bit error rate performance by applying companding transform technique. Hence, 1-1.5 dB reduction in PAPR with this Non-companding technique is achieved. In Future, We can accept to implement the same on Rician and Rayleigh channels.

  • 115.
    Baig, Mirza Hamid
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Kiani, Hassan Shahzad
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Performance Evaluation of MANET using MPLS2010Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Mobile Ad Hoc Network (MANET) is special kind of wireless network which does not have any fixed structure. They are paired for specific purpose within some concise time period. As the concept of “Micro Products” with a feature of “Mobility” has gain popularity, the MANET has benefited the mankind in many ways and in number of situations such as Natural Disaster, War Zone, and Medical Camp in far-flung Earthquake hit areas etc. In every situation mobile nodes organized themselves on temporary bases in network topology. Autonomous nodes having wireless infrastructure are interconnected to form an autonomous network and easily establish a connection from one place to another. These mobile nodes act either as routers or as a host. These nodes have routing capabilities for multi hop paths through which these are interconnected. The mobility of nodes needs efficient routing for MANET. So therewith, Multi Protocol Label Switching (MPLS) enhances routing with respect to path and packet forwarding. In our thesis we try to analyze the various effects of MPLS on MANET protocols when integrated with MPLS. Simulations were carried out using OPNET modeler 14.5 for analyzing the MPLS effects on the metrics like route discovery time, packet end-to-end delay and throughput. Moreover case study is also included to present a conceptual model for integrating MPLS with MANET protocols.

  • 116.
    Bajwa, Ahmer Ali
    et al.
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för signalbehandling.
    Awan, Junaid Anwar
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för signalbehandling.
    Performance study of IEEE 802.16d (Fixed WiMAX) Physical layer with Adaptive Antenna System2008Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    In this thesis work, WiMAX (IEEE 802.16d) PHY layer with underlying OFDM technology and an optional feature called Adaptive Antenna System has been considered. The SUI-3 channel model (Rician fading) is used for creating fading phenomena. An Adaptive Antenna System has been deployed at the receiver module to reduce the fading effects caused by SUI-3 channel model. Adaptive Antenna Systems (AAS) uses different beamforming techniques to focus the wireless beam between the base station and the subscriber station. In this thesis, the transmitter (SS) and receiver (BS) are fixed and AAS installed at the receiver is used to direct the main beam towards the desired LOS signal and nulls to the multipath signals. Pre-FFT beamformer based on Least Mean Square (LMS) algorithm is used. Different aspects of the complete system model were investigated such as adaptive modulation, angle of arrival of the incoming signals and number of array elements. It has been demonstrated through MATLAB simulations that the performance of the system significantly improves by AAS, where beamforming is implemented in the direction of desired user. The performance of the system further increases by increasing the number of antennas at receiver.

  • 117.
    Bandari Swamy Devender, Vamshi Krishna
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för datavetenskap.
    Adike, Sneha
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för datavetenskap.
    Design and Performance of an Event Handling and Analysis Platform for vSGSN-MME event using the ELK stack2019Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Data Logging is the main activity to be considered in maintaining a server or database in working condition without any errors or failures. Data collection can be automatic, so, no human presence is necessary. To store the data of logs for many days and visualizing became a huge problem in recent days. Coming to node SGSN-MME, which is the main component of the GPRS network, which handles all packet switched data within the mobile operator's network. A lot of log data is generated and stored in file systems on the redundant File Server Boards in SGSN-MME node. The evolution of the SGSN-MME is taking it from dedicated, purpose-built, hardware into virtual machines in the Cloud, where virtual file server boards fit very badly. The purpose of this thesis is to give a better way to store the log data and add visualization using the ELK stack concept. Fetching useful information from logs is one of the most important part of this stack and is being done in Logstash using its grok filters and a set of input, filter and output plug-ins which helps to scale this functionality for taking various kinds of inputs ( file,TCP, UDP, gemfire, stdin, UNIX, web sockets and even IRC and twitter and many more) , filter them using (groks,grep,date filters etc.)and finally write output to ElasticSearch. The Research Methodology involved in carrying out this thesis work is a Qualitative approach. A study is carried using the ELK concept with respect to Legacy approach in Ericsson company. A suitable approach and the better possible solution is given to the vSGSN-MME node to store the log data. Also to provide the performance and uses multiple users of input providers and provides the analysis of the graphs from the results and analysis. To perform the tests accurately, readings are taken in defined failure scenarios. From the test cases, a plot is provided on the CPU load in vSGSN-MME which easily gives the suitable and best promising way.

  • 118.
    Bandreddy, Pavan
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Pokala, Bhargav
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Perceptual Video Quality Assessment Tool2011Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Compressing the video data is necessary for video transmission over networks with limited resources. Video quality at the end is based on the compression techniques used. In this research work, we mainly focused on compressing video files using H.264 encoding by considering some parameters and conducting a subjective test on the resulting compressed videos in a specially developed Perceptual Video Quality Assessment (PVQA) tool. This PVQA tool was developed as part of the thesis project. For the compression techniques, we have considered spatial resolutions (i.e. VGA and QVGA), temporal resolutions (i.e. 25fps and 12.5fps) and bit rate (i.e. 300kbps and 600kbps). By considering these parameters for three different test sequences, we down scaled and encoded to transmit over lossless channel. The received data is decoded and up scaled using open source software’s. For encoding and decoding of videos in H.264, we used JM reference software. For scaling the videos spatially and temporally, both FFMPEG and Virtual Dub are used. For up scaling the decoded video in spatial resolution (QVGA to VGA) two filter methods are used i.e. Bicubic Interpolation and Nearest Neighbor technique in Virtual Dub. For up scaling in temporal resolution (12.5fps to 25fps) the repeat frame method of Virtual Dub is used. These generated videos were evaluated by conducting subjective tests to determine the best technique that is suitable for transmission over a bit rate limited network. The developed PVQA tool satisfies the requirements of International Telecommunication Union (ITU) standard ITU-R BT.500-12. The PVQA tool will ask the subjects to grade the videos quality according to his/her experience and these grades are saved in excel sheets. The PVQA tool was developed under Java environment, with the VLC player embedded. The tool was designed to support the video. Results of the subjective video quality survey are summarized and finally conclusions are given.

  • 119. Bao, Vo Nguyen Quoc
    et al.
    Duong, Quang Trung
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Exact Outage Probability of Cognitive Underlay DF Relay Networks with Best Relay Selection2012Ingår i: IEICE transactions on communications, ISSN 0916-8516, E-ISSN 1745-1345, Vol. E95-B, nr 6, s. 2169-2173Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this letter, we address the performance analysis of underlay selective decode-and-forward (DF) relay networks in Rayleigh fading channels with non-necessarily identical fading parameters. In particular, a novel result on the outage probability of the considered system is presented. Monte Carlo simulations are performed to verify the correctness of our exact closed-form expression. Our proposed analysis can be adopted for various underlay spectrum sharing applications of cognitive DF relay networks.

  • 120. Bao, Vo Nguyen Quoc
    et al.
    Duong, Quang Trung
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Outage Analysis of Cognitive Multihop Networks under Interference Constraints2012Ingår i: IEICE transactions on communications, ISSN 0916-8516, E-ISSN 1745-1345, Vol. E95-B, nr 3Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The closed-form expressions for outage probability, bit error rate, and ergodic capacity of spectrum sharing-based multi-hop decode-and-forward relay networks in non-identical Rayleigh fading channels are derived. Utilizing these precise and tractable analytical formulas, we can study the impact of key network parameters on the performance of cognitive multi-hop relay networks under interference constraints. The analytical expressions are verified by Monte-Carlo simulations.

  • 121. Bao, Vo Nguyen Quoc
    et al.
    Duong, Quang Trung
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    da Costa, Daniel Benevides
    Alexandropoulos, George C.
    Nallanathan, A.
    Cognitive Amplify-and-Forward Relaying with Best Relay Selection in Non-Identical Rayleigh Fading2013Ingår i: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 17, nr 3, s. 475-478Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper investigates several important performance metrics of cognitive amplify-and-forward (AF) relay networks with a best relay selection strategy and subject to nonidentical Rayleigh fading. In particular, assuming a spectrum sharing environment consists of one secondary user (SU) source,K SU relays, one SU destination, and one primary user (PU) receiver, closed-form expressions for the outage probability (OP), average symbol error probability (SEP), and ergodic capacity of the SU network are derived. The correctness of the proposed analysis is corroborated via Monte Carlo simulations and readily allows us to evaluate the impact of the key system parameters on the end-to-end performance. An asymptotic analysis is also carried out and reveals that the diversity gain is defined by the number of relays pertaining to the SU network (i.e., K), being therefore not affected by the interference power constraint of the PU network.

  • 122. Barbosa, V.L.
    et al.
    E.R., Schlosser
    Machado, Renato
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för matematik och naturvetenskap.
    F. G., Ferreira
    S. M., Tolfo
    M. V. T., Heckler
    Linear Array Design with Switched Beams for Wireless Communications Systems2015Ingår i: International Journal of Antennas and Propagation, ISSN 1687-5869, E-ISSN 1687-5877, Vol. 2015, artikel-id 278160Artikel i tidskrift (Refereegranskat)
  • 123.
    Bardici, Nick
    et al.
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för signalbehandling.
    Skarin, Björn
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för signalbehandling.
    Röstigenkänning genom Hidden Markov Model: En implementering av teorin på DSP2006Självständigt arbete på avancerad nivå (magisterexamen)Studentuppsats (Examensarbete)
    Abstract [sv]

    Detta examensarbete går ut på att implementera en röstigenkänningssystem på en DSK – ADSP-BF533 EZ-KIT LITE REV 1.5 baserad på teorin om HMM, Hidden Markov Model. Implementeringen är baserad på teorin i examensarbetet Speech Recognition using Hidden Markov Model av Mikael Nilsson och Marcus Ejnarsson, MEE-01-27. Det som gjorts i arbetet är att utifrån teorin implementerat en MFCC, Mel Frequency Cepstrum Coefficient funktion, en träningsfunktion som skapar Hidden Markov Modeller av unika uttalanden av ord och en testfunktion som testar ett uttalat ord mot de olika modellerna som skapades av träningsfunktionen. Dessa funktioner skapades först i MatLab. Sedan implementerades testprogrammet på DSP:n Texas Instruments TMDS320x6711. Sedan utvärderades realtidstillämpningen.

  • 124.
    Baskaravel, Yogaraj
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för datalogi och datorsystemteknik.
    Implementation and evaluation of global router for Information-Centric Networking2014Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Context. A huge majority of the current Internet traffic is information dissemination. Information-Centric Networking (ICN) is a future networking paradigm that focuses on global level information dissemination. In ICN, the communication is defined in terms of requesting and providing Named Data Objects (NDO). NetInf is a future networking architecture based on Information-Centric Networking principles. Objectives. In this thesis, a global routing solution for ICN has been implemented. The authority part of NDO's name is mapped to a set of routing hints each with a priority value. Multiple NDOs can share the same authority part and thus the first level aggregation is provided. The routing hints are used to forward a request for a NDO towards a suitable copy of the NDO. The second level aggregation is achieved by aggregating high priority routing hints on low priority routing hints. The performance and scalability of the routing implementation are evaluated with respect to global ICN requirements. Furthermore, some of the notable challenges in implementing global ICN routing are identified. Methods. The NetInf global routing solution is implemented by extending NEC's NetInf Router Platform (NNRP). A NetInf testbed is built over the Internet using the extended NNRP implementation. Performance measurements have been taken from the NetInf testbed. The performance measurements have been discussed in detail in terms of routing scalability. Results. The performance measurements show that hop-by-hop transport has significant impact on the overall request forwarding. A notable amount of time is taken for extracting and inserting binary objects such as routing hints at each router. Conclusions. A more suitable hop-by-hop transport mechanism can be evaluated and used with respect to global ICN requirements. The NetInf message structure can be redefined so that binary objects such as routing hints can be transmitted more efficiently. Apart from that, the performance of the global routing implementation appears to be reasonable. As the NetInf global routing solution provides two levels of aggregation, it can be scalable as well.

  • 125. Bayley, Todd
    et al.
    Rohani, Bijan
    Johansson, Anders
    Caldera, Manora
    Zepernick, Hans-Jürgen
    Call Quality Monitoring for VoIP2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    A method of monitoring the speech quality of a Voice-over-IP call is described in this paper. This method is attractive because it employs the ITU-T standard P.862 for Perceptual Evaluation of Speech Quality which is well-known for its accuracy. In addition, with the proposed method, call quality is monitored without interfering with the call while it is in progress. The results corresponding to an implementation of this method shows call quality can be measured with excellent accuracy under typical network delays.

  • 126.
    Bejjenki, Praneeth Kumar
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Goraya, Muneeb Ahmed
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Moid, Syed Fovad
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    OPTIMIZED FUZZY BASED POWER CONTROL STRATEGY IN COGNITIVE RADIO NETWORKS IN MULTI FADING PROPAGATION ENVIRONMENTS2013Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    In this thesis we have considered a cognitive radio network (CRN) with a pair of primary user (PU) and secondary user (SU) in spectrum sharing networks in path-loss and without path-loss propagation environments under identically distributed m-Nakagami fading channel. The thesis consists of three parts. In the first part we propose an optimized Takagi-Sugeno Fuzzy Inference System (FIS) based power control strategy in cognitive radio networks (CRN) in spectrum sharing network in without path-loss propagation environment. The second part proposes an optimized Takagi-Sugeno FIS based power control strategy in cognitive radio networks in spectrum sharing network in path-loss propagation environment. For without path-loss propagation environment the proposed FIS takes the interference channel gain ratio between SU transmitter (CUtx) and PU receiver (PUrx) and Signal to Noise Ratio (SNR) towards PU transmitter (PUtx) as antecedents and outputs the power scaling factor for SU. For path-loss propagation environment the proposed FIS takes the relative distance ratio between CUtx and PUrx and SNR towards PUtx as antecedents and outputs the power scaling factor for SU. The output power scaling factor is used to vary the transmit power of SU such that it does not degrade the quality of service (QoS) of PU link. The third part presents an implementation of orthogonal frequency division multiplexing (OFDM) transmission technique in CRN. The OFDM technique has intellectual attractive features like coping with the inter symbol interference (ISI), while providing increasing spectral efficiency and improved performance. This can be used in emergency conditions where transmission requires reliability and high data rate. The OFDM transmission technique is applied towards SU transmitter in CRN, which enables SU to utilize the spectrum efficiently under various fading environments. Spectrum sharing networks in with and without path-loss propagation environments and OFDM transmission were tested for bit error rate (BER) performance after fading effects from m-Nakagami fading channel. We conclude that by applying Takagi-Sugeno Fuzzy Inference System (FIS) based power control strategy we can improve the BER performance of PU when compared with no power control strategy and with other fuzzy based power control technique. OFDM transmission technique gives us better data rate and slightly improved BER in CRN hence making it suitable for use in emergency conditions.

  • 127.
    Bengtsson, Christofer
    et al.
    Blekinge Tekniska Högskola, Sektionen för management.
    Wahlström, Johan
    Blekinge Tekniska Högskola, Sektionen för management.
    Vilka strategiska åtgärder krävs av 3G-mobiloperatörerna för att locka till sig konsumenter?2004Självständigt arbete på grundnivå (kandidatexamen)Studentuppsats (Examensarbete)
    Abstract [sv]

    Genom en enkätundersökning till konsumenter har vi kommit fram till att det är lägre kostnader, bättre information och bättre täckning som är de optimala faktorerna för 3G-operatörerna att kunna locka till sig fler konsumenter.

  • 128. Berg, Magnus
    et al.
    Bondesson, Erik
    Low, Siow Yong
    Nordholm, Sven
    Claesson, Ingvar
    A combined on-line PCA-ICA algorithm for blind source separation 2005Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we introduce and investigate a method combining principle component analysis (PCA) and independent component analysis (ICA) for blind source separation (BSS). A recursive method for the PCA is applied to meet the demands of a real-time application, and likewise a modified on-line version of the information maximization principle is used. The combined PCA-ICA algorithm, first reduces the dimension of the problem and then separates the signals. Evaluation of the proposed algorithm in a real room shows superior noise suppression capabilities compared to the use of PCA or ICA individually. The proposed algorithm achieves an impressive noise suppression/separation of up to 14 dB with only two microphones. Most importantly this is achieved with negligible distortion of the recovered signal. © 2005 IEEE.

  • 129.
    Bergstrand, Catharina
    Blekinge Tekniska Högskola, Institutionen för telekommunikation och signalbehandling.
    Parallellpublicering2002Självständigt arbete på grundnivå (kandidatexamen)Studentuppsats (Examensarbete)
    Abstract [sv]

    Examensarbete är utfört för Gothia System Office AB och innebar att analysera och ta fram ett exempel på hur parallellpublicering fungerar. Parallellpubliceringsexemplet är baserat på Oracle 8.1.7 databas som är implementerad med testdata via script. Själva Parallellpubliceringsprogrammet är skrivet i Java och dess uppgift är att publicera data från databasen med olika utseende beroende på vad man skall använda det till. Utmatning av data från databasen sker via XML som sedan tillförs ett XSL style sheet, eller bearbetas om, av Java-applikation för det slutgiltiga målet. Programvaran som används för att utveckla Java-applikationen är JDeveloper 3.2 och för att framställa dataanalysen, UML = Unified Modeling Language, så används Together 5.02.

  • 130. Berndtsson, Fredrik
    Bluetooth vs RFID in Time Tracking2017Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Bluetooth och Radio Frequency Identification (RFID) är två vanliga teknologier som användsi stor utsträckning idag, till exempel Bluetooth används för bland annat kommunikation mellan enheter, medans RFID används bland anatt för identifiering av objekt i lagerlokaler. Detta arbetet jämför teknologierna utifrån ett tidtagnings perspektiv för olika idrottslopp. För jämförelsen mellan teknologierna utvecklades en Bluetooth tidtagnings prototyp baserat på en Raspberry Pi 3 och en smartphone applikation, och för RFID användes ett redan utvecklat tidtagningssystem.

    Arbetet har utförts på Blekinge Tekniska Högskola i Karlskrona. Ett iterativt arbetssätt hara nvänts under arbetes gång innefattande en förstudie, utveckling, verifikation, experiment ochen enkätfas. Enkäten fokuserade på smartphones för tidtagning och experimenten som utfördes var av kvalitativ karaktär. Två av forskningsfrågorna som blivit besvarade under arbetet är om Bluetooth kan användas för tidtagning och om det går, vad är skillnaden på prestandan i låga respektive höga hastigheter på olika avstånd?

    Några av resultaten från arbetet är att i fri sikt kan Bluetooth bli läst på längre avstånd än RFID. Båda systemen kan läsa av taggar upp till 30 kilometer i timmen nära läsaren.

  • 131.
    Bertilsson, Tobias
    et al.
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för telekommunikationssystem.
    Nilsson, Fredrik
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för telekommunikationssystem.
    En butik på Internet, Grandpa AB2004Självständigt arbete på grundnivå (kandidatexamen)Studentuppsats (Examensarbete)
    Abstract [sv]

    Idag är webbhandel en del av vardagen och är ett utmärkt sätt för ett företag att kunna locka till sig nya kunder. Detta är något som den ny öppnade butiken Grandpa insåg och de ville därför ha en mer utvecklad webbsida. Till vårt förfogande för att skapa denna hade vi html, PHP, JavaScript™ och MySQL. Detta för att systemet senare skulle kunna fungera på en Linux-server. Uppdraget var att skapa en webblösning med dessa element där besökare kan ta del av information och bilder som bl.a. finns sparade i en databas. Webbplatsen skulle vara enkel att administrera för de anställda och lätt att navigera för besökarna. Besökare skulle också kunna erbjudas att kunna beställa varor och där efter betala via postförskott. I rapporten beskriver vi de olika teknikerna som vi använt oss av och på vilket sätt dessa använts. Vi visar också hur olika användarscenarion kan påverka sidan. För att kunna skapa en användarvänlig hemsida har en förstudie gjorts, den finns sammanfattad i denna rapport. Resultatet av vårt arbete blev en fungerande hemsida där besökarna erbjuds att läsa krönikor, tips, anmäla sig till nyhetsbrev och att kunna köpa varor

  • 132.
    Bertilsson, Tobias
    et al.
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för telekommunikationssystem.
    Persson, Mårten
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för telekommunikationssystem.
    Situation-dependent spontaneous mobile information service for travelers2006Självständigt arbete på avancerad nivå (magisterexamen)Studentuppsats (Examensarbete)
    Abstract [sv]

    Examensarbetet tog fram en demonstrationstjänst för det VINNOVA-sponsrade projekt PIITSA (Personlig Information i Intelligenta Transportsystem genom Sömlös kommunikation och Autonoma beslut). Den används på en handdator och hjälper resenrärer "att komma från A till B i alla fall" genom att ge möjlighet att söka eller lägga in reserutter och övervaka aktuell trafikinformation i samband med dessa rutter, främst avseende kollektivtrafik i Stockholmsområdet. Mervärdet består i att resenären blir varnat automatiskt om någonting händer längs de valda rutterna och ges möjlighet att få en ny rutt. Applikationen kan användas i skarp läge.

  • 133.
    Bethalam, Anil Varma
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Amburu, Prasanna Kumar
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Causes of TCP Reset in Mobile Web Browsing2011Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Web browsing has been one of the most popular activities on the internet. The increasing importance of the Web in everyday life calls for device-independent access to existing web sites. Although, there is full Web access available on mobile phones the user experience is often poor when compared to the Web user experience on Personal Computer (PC). Therfore, it is important for the Internet service provider to find the indications of user dissatisfaction from the network. While using the mobile Web, user can normally abort the transfer by pressing the stop or reset buttons in the browsers, leaving the page being downloaded by following a bookmark or can close the connection. Such events can be observed through the TCP reset (RST) flag from traffic on network level. In this thesis we have investigated the possible causes of TCP RST flags mobile Web session is interrupted. We further analyze up to what extent we can rely on TCP RST flags for being an indication of user dissatisfaction in mobile web browsing. Therefore, an experiment testbed is developed to capture the TCP packet traces during controlled active tests. Results are gathered using mobile devices with four popular mobile operating systems (OS). The trace files captured are analyzed using perl script to dicern the flow and focusing on the TCP RST flag during the flow. Further, TSTAT tool is used to validate our trace files.

  • 134.
    Bhamidipati, Vasanthi Dwaraka
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Kilari, Swetha
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Effect of Delay/Delay Variation on QoE in Video Streaming2010Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Video streaming has become the most important way to share video and audio over a network. It is being used for video conferencing, e-learning etc. The user‟s quality of experience of watching a video is of utmost importance for the content providers. The video quality is much affected because of packet loss and delay in the network which in turn lowers user‟s perception on quality of the received videos. In our thesis we try to find out the effect of delay/delay variation on the quality of experience of the users. We try to evaluate the quality of experience using mean opinion score. The quality of experience as perceived by the user is analyzed for all the videos that we have taken and are streamed with constant and varying delay. From this we were able to find the threshold level of delay that is acceptable by the users. The user‟s tolerance towards the quality of the video in a network with a varying delay is analyzed. The effect of packet delay has also been investigated and the results have been analyzed using Excel.

  • 135. Bhole, Yogesh
    et al.
    Popescu, Adrian
    Measurement and Analysis of HTTP Traffic2005Ingår i: Journal of Network and Systems Management, ISSN 1064-7570, E-ISSN 1573-7705, Vol. 13, nr 4, s. 357-371Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The usage of Internet is rapidly increasing and a large part of the Internet traffic is generated by the World Wide Web (WWW) and the associated protocol HiperText Transfer Protocol (HTTP). Several important parameters that affect the performance of the WWW are bandwidth, scalability and latency. To tackle these parameters and to improve the overall performance of the system, it is important to understand and to characterize the application level characteristics. This article is reporting on the measurement and analysis of HTTP traffic collected on the student access network at the Blekinge Institute of Technology in Karlskrona, Sweden. The analysis is done on various HTTP traffic parameters, e.g., inter-session timings, inter-arrival timings, request message sizes, response code and number of transactions. The reported results can be useful for building synthetic workloads for simulation and benchmarking purposes.

  • 136.
    Bhuiya, Monirul Islam
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Rakib, Mohammad Ahsan
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Performance Evaluation of DHTs for Mobile Environment2010Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Distributed Hash Table (DHT) systems are an important part of peer-to-peer routing infrastructures. They enable scalable wide-area storage and retrieval of information, and will support the rapid development of a wide variety of Internet-scale applications ranging from naming systems and file systems to application-layer multicast. A lot of research about peer-to-peer systems, today, has been focusing on designing better structured peer-to-peer overlay networks or Distributed Hash Tables (DHTs). As far as we concern, not so many papers, however, have been published in an organized way to check the adaptability of the existing four DHTs namely Content Addressable Network (CAN), Chord, Pastry and Tapestry for mobile environments. This thesis presents an attempt to evaluate the performances of these DHTs including adaptability with mobile environments. For this we survey these DHTs including existing solutions and based on that we decide our own conclusion.

  • 137.
    Bhuma, Venkata Srikanth
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Balsu, Santosh Kumar
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Evaluation Of Radiation Tolerant Satellite Communication Modem2012Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    The design specification of CubeSat standards by California Polytechnique University has become a major milestone in development and deployment of nano satellites. The number of CubeSats that are being deployed into the orbit has increased in recent years. The design and development have been transformed from traditional hardware devices to software defined radios. However there is a lack of clear understanding and concrete findings on developing proper communication transceivers. The lack of knowledge of proper guidelines to be followed to design and develop communication subsystems prompts and acts as a base for us in understanding the communication subsystem design standards followed by CubeSat projects in various universities. Particular attention is given to those CubeSats that are currently in the orbit and are under development. The main aim of the thesis is to identify the challenges faced by the CubeSat developers and provide guidelines for future developers in order to overcome those challenges to reduce the development time and costs which are major constraints in CubeSat developments. A traditional literature review process was followed in order to identify the potential issues and in parallel a modem was designed and implemented in order to know some more challenges while developing a CubeSat modem. From the literature review method, eight potential issues were identified and an additional two more challenges were experienced while implementing a modem. Potential advantages and disadvantages of using nanoRTU have also been identified as part of the work.

  • 138.
    Bhutto, Tarique Inayat
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Root LDPC Codes for Non Ergodic Transmission Channels2011Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    4 ABSTRACT Tremendous amount of research has been conducted in modern coding theory in the past few years and much of the work has been done in developing new coding techniques. Low density parity check (LDPC) codes are class of linear block error correcting codes which provide capacity performance on a large collection of data transmission and storage channels while Root LDPC codes in this thesis work are admitting implementable decoders with manageable complexity. Furthermore, work has been conducted to develop graphical methods to represent LDPC codes. This thesis implement one of the LDPC kind “Root LDPC code” using iterative method and calculate its threshold level for binary and non-binary Root LDPC code. This threshold value can serve as a starting point for further study on this topic. We use C++ as tool to simulate the code structure and parameters. The results show that non-binary Root LDPC code provides higher threshold value as compare to binary Root LDPC code.

  • 139.
    Bilal, Adeel Ashfaq and Umer
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Study of Abnormal TCP/HTTP Connection2011Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Web browsing activities have increased to huge volumes in the last decade, causing more interest in the analysis of Web trac to extract user action. TCP, the transport layer protocol and HTTP, the application layer protocol plays a major role in Web browsing activities. In this thesis an attempt has been made to investigate the anomalies of TCP terminations in an application layer environment. An experimental setup has been devised in in an isolated manner to observe the e ect of di erent Web browsers, Web servers and contents type on the termination of TCP ports. The results in this thesis show that the anomaly of the termination of TCP port with a reset(RST) flag is usually caused by a Web browser. Further we conclude that the amount of RSTs rise while accessing video based contents due to the increased number of ports while accessing the contents of Web page. In this report ,we further describe and quantify the di erent causes and their contribution in generating RSTs during Web browsing.

  • 140. Binzenhöfer, Andreas
    et al.
    Schlosser, Daniel
    Tutschku, Kurt
    Fiedler, Markus
    An Autonomic Approach to Verify End-to-End Communication Quality2007Konferensbidrag (Refereegranskat)
    Abstract [sv]

    Pappret beskriver ett nytt sätt att hantera prestandaövervakning med hjälp av overlay-teknologi, vilket togs fram inom projektet "AutoMon", finansierad av det europeiska Network of Excellence "EuroNGI". Autonomic networking, end-to-end Quality of Service (QoS), kvalitetsåterkoppling

  • 141. Binzenhöfer, Andreas
    et al.
    Tutschku, Kurt
    Graben, Björn auf dem
    Fiedler, Markus
    Arlos, Patrik
    A P2P-based framework for distributed network management2006Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper we present a novel framework supporting distributed network management using a self-organizing peer-to-peer overlay network. The overlay consists of several Distributed Network Agents which can perform distributed tests and distributed monitoring for fault and performance management. In that way, the concept is able to overcome disadvantages that come along with a central management unit, like lack of scalability and reliability. So far, little attention has been payed to the quality of service experienced by the end user. Our self-organizing management overlay provides a reliable and scalable basis for distributed tests that incorporate the end user. The use of a distributed, self-organizing software will also reduce capital and operational expenditures of the operator since fewer entities have to be installed and operated.

  • 142. Binzenhöfer, Andreas
    et al.
    Tutschku, Kurt
    Graben, Björn auf dem
    Fiedler, Markus
    Arlos, Patrik
    DNA, a P2P-based framework for distributed network management2005Konferensbidrag (Refereegranskat)
    Abstract [sv]

    Beskriver en ny management infrastruktur för övervakningen av end-till-end tjänstekvalitet.

  • 143.
    Biswas, Kamanashis
    et al.
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för för interaktion och systemdesign.
    Ali, Md. Liakat
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för för interaktion och systemdesign.
    Security Threats in Mobile Ad Hoc Network2007Självständigt arbete på avancerad nivå (magisterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Mobile Ad Hoc Network (MANET) is a collection of communication devices or nodes that wish to communicate without any fixed infrastructure and pre-determined organization of available links. The nodes in MANET themselves are responsible for dynamically discovering other nodes to communicate. Although the ongoing trend is to adopt ad hoc networks for commercial uses due to their certain unique properties, the main challenge is the vulnerability to security attacks. A number of challenges like open peer-to-peer network architecture, stringent resource constraints, shared wireless medium, dynamic network topology etc. are posed in MANET. As MANET is quickly spreading for the property of its capability in forming temporary network without the aid of any established infrastructure or centralized administration, security challenges has become a primary concern to provide secure communication. In this thesis, we identify the existent security threats an ad hoc network faces, the security services required to be achieved and the countermeasures for attacks in each layer. To accomplish our goal, we have done literature survey in gathering information related to various types of attacks and solutions, as well as we have made comparative study to address the threats in different layers. Finally, we have identified the challenges and proposed solutions to overcome them. In our study, we have found that necessity of secure routing protocol is still a burning question. There is no general algorithm that suits well against the most commonly known attacks such as wormhole, rushing attack etc. In conclusion, we focus on the findings and future works which may be interesting for the researchers like robust key management, trust based systems, data security in different layer etc. However, in short, we can say that the complete security solution requires the prevention, detection and reaction mechanisms applied in MANET.

  • 144.
    Biswas, Md Abdul Matin
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Exploiting the Direct Communication Link for Enhancing Effective Capacity Performance of Cognitive Radio Relay Networks2014Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Nowadays, cognitive radio (CR) is a promising concept to improve the radio spectrum exploitation. CR has tremendous ability to enhance spectrum efficiency by allowing secondary users (SUs) to access licensed radio spectrum resource which is currently not being used by primary users (PUs). One basic challenge of that paradigm is securing the quality of service (QoS) of the primary link transmission while increasing the rate of the secondary links transmission. Cooperative relaying is an encouraging technology which offers the opportunity to maximize the transmission diversity gain significantly in the rapid development growth of wireless communication which contains cognitive radio networks. On the other hand, effective capacity (EC) which is designed to provide a maximum constant arrival rate that a statistical wireless channels can support while satisfying statistical QoS requirements. In this thesis, the performance enhancement analysis of cognitive radio relay network (CRRN) by exploiting the direct communication link has been investigated in Rayleigh fading channel where peak interference power constraint is taken into consider. A spectrum sharing technique is considered in this thesis where a restriction of spectrum sharing is applied by the PUs. Here, an SU can coexist simultaneously with the PU for transmitting data as long as a certain threshold on the peak interference power applied on the primary receiver is not overstepped by the SUs transmission. In addition, it is supposed that there are multiple intermediate relay nodes available to transmit their signal to the destination along with a direct communication link for secondary transmission. Moreover, the SU transmission has to meet a random delay QoS constraint. By providing this QoS constraint, the maximum arrival data rate of SUs can be achieved with small error of probability. Specifically, this thesis also acquires closed-form expressions of EC for CRRN. It is evident that if the channel quality and the interference threshold set by the PU are changed, then the capacity of the channel is also to be changed. In addition, it is also verified that the direct communication link together with multiple relay nodes has significantly higher capacity gains compare to non-direct communication link for CRRN. Matlab simulations are presented to find out theoretical results and Monte-Carlo simulations are carried out to support these numerical results. Both the simulation results and the analytical results match very well.

  • 145.
    Björklund, Svante
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för matematik och naturvetenskap.
    Clutter Properties for a Side-Looking Radar with Planar Regular and Irregular Subarrays2015Ingår i: 2015 16TH INTERNATIONAL RADAR SYMPOSIUM (IRS), 2015, s. 730-735Konferensbidrag (Refereegranskat)
    Abstract [en]

    The effect of the subarray design in a side-looking moving radar with a planar antenna on some clutter properties which are important for suppressing the clutter with STAP (Space-Time Adaptive Processing) is investigated by simulations. These properties are interference DOA Doppler Spectrum (DDS) and clutter rank. The conclusions from the work is that irregular antennas give less clutter in the DDS and that larger subarrays give lower clutter rank.

  • 146.
    BONAM, VEERA VENKATA SIVARAMAKRISHNA
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för datalogi och datorsystemteknik.
    Multipath TCP and Measuring end-to-end TCP Throughput: Multipath TCP Descriptions and Ways to Improve TCP Performance2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Internet applications make use of the services provided by a transport protocol, such as TCP (a reliable, in-order stream protocol). We use this term Transport Service to mean the end-to- end service provided to application by the transport layer.

     

    That service can only be provided correctly if information about the intended usage is supplied from the application. The application may determine this information at the design time, compile time, or run time, and it may include guidance on whether a feature is required, a preference by the application, or something in between.

    Multipath TCP (MPTCP) adds the capability of using multiple paths to a regular TCP session. Even though it is designed to be totally backward compatible to applications. The data transport differs compared to regular TCP, and there are several additional degrees of freedom that the particular application may want to exploit.

     

    Multipath TCP is particularly useful in the context of wireless networks using both Wi-Fi and a mobile network is a typical use case. In addition to the gains in throughput from inverse multiplexing, links may be added or dropped as the user moves in or out of coverage without disrupting the end-to-end TCP connection. The problem of link handover is thus solved by abstraction in the transport layer, without any special mechanisms at the network or link level.

     

    Handover functionality can then be implemented at the endpoints without requiring special functionality in the sub-networks according to the Internet's end-to-end principle. Multipath TCP can balance a single TCP connection across multiple interfaces and reach very high throughput.

  • 147. Boulliant, David
    et al.
    Pruthi, Parag
    Popescu, Adrian
    Estimation of Long-Range Dependence Using Wavelets1998Konferensbidrag (Refereegranskat)
    Abstract [en]

    A wavelet-based tool is reported for the analysis of Long-Range Dependence (LRD) traffic to allow for semiparametric estimation of the Hurst (H) parameter. Validation has been also done, by using fBm and fGn models, and the obtained estimations show excellent agreements with the theoretical results.

  • 148. Boulliant, David
    et al.
    Pruthi, Parag
    Popescu, Adrian
    Traffic Characterization Using Wavelet-Based Techniques1998Konferensbidrag (Refereegranskat)
    Abstract [en]

    Study of long-range dependence (LRD) properties in real traffic has received an increasing attention in traffic analysis. A wavelet-based tool for the analysis of LRD is presented in this paper together with a semi-parametric estimator of the Hurst parameter. The estimator has been proved to be unbiased under very general conditions and efficient under Gaussian assumptions. Analysis of the Bellcore Ethernet traces as well as of some VBR video traces using the wavelet-based estimator is reported.

  • 149.
    Brozovic, Martin
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    ON EFFICIENT AUTOMATED METHODS FOR SIMULATION OUTPUT DATA ANALYSIS2014Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    With the increase in computing power and software engineering in the past years computer based stochastic discrete-event simulations have become very commonly used tool to evaluate performance of various, complex stochastic systems (such as telecommunication networks). It is used if analytical methods are too complex to solve, or cannot be used at all. Stochastic simulation has also become a tool, which is often used instead of experimentation in order to save money and time by the researchers. In this thesis, we focus on the statistical correctness of the final estimated results in the context of steady-state simulations performed for the mean analysis of performance measures of stable stochastic processes. Due to various approximations the final experimental coverage can differ greatly from the assumed theoretical level, where the final confidence intervals cover the theoretical mean at much lower frequency than it was expected by the preset theoretical confidence level. We present the results of coverage analysis for the methods of dynamic partially-overlapping batch means, spectral analysis and mean squared error optimal dynamic partially-overlapping batch means. The results show that the variants of dynamic partially-overlapping batch means, that we propose as their modification under Akaroa2, perform acceptably well for the queueing processes, but perform very badly for auto-regressive process. We compare the results of modified mean squared error optimal dynamic partially-overlapping batch means method to the spectral analysis and show that the methods perform equally well.

  • 150. Buchinger, Shelley
    et al.
    Lopez, Rui Jorge
    Jumisko-Pyykkö, Satu
    Zepernick, Hans-Jürgen
    Quality of Experience for Multimedia Content Sharing: Ubiquitous QoE assessment and support2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    In recent years, it has been realized that the success of multimedia services or applications relies on the analysis of the entire user experience (UX). The relevance of this paradigm ranges from IPTV to video-on-demand systems o ering professional TV and user-generated content that is consumed and produced ubiquitously. To obtain a pleasurable and ubiquitous user experience a large amount of aspects have to be taken into account. Major challenges in this context include the identi cation of relevant UX factors and the quanti cation of their inuence on Quality of Experience (QoE). In the particular scenario of ubiquitous production and consumption of content, context awareness and assessment of users' expectations play an essential role. This is further justi ed by the emergence of new multimedia enhancement techniques, notably 3DTV and Free Viewpoint. In the support of ubiquitous QoE the acquired knowledge on the context and on identi ed parameters a ecting users' experience could be used to improve mutimedia applications and their associated content delivery mechanisms.

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