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  • 51.
    Gade, Vaibhav
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Intrusion Detection System as a Service: Providing intrusion detection system on a subscription basis for cloud deployment2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
  • 52.
    Galely, Insiya
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    The attitude of mother tongue education in correlation with academic performance - A study of the different components of attitude in Indian students living in Egypt.2014Självständigt arbete på grundnivå (kandidatexamen)Studentuppsats (Examensarbete)
    Abstract [sv]

    Den här studien undersöker ifall det finns en relation mellan attityder till andra elevers modersmål och ifall denna attityd påverkar elevernas akademiska prestation.

  • 53.
    Gharari, Farnaz
    et al.
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för tillämpad signalbehandling.
    Chu, Thi My Chinh
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Zepernick, Hans-Jürgen
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Performance Analysis of a Piecewise-and-Forward Relay Network on Rayleigh Fading Channels2015Ingår i: 2015 9TH INTERNATIONAL CONFERENCE ON SIGNAL PROCESSING AND COMMUNICATION SYSTEMS (ICSPCS), IEEE Communications Society, 2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we analyse the performance of a cooperative communication network with multiple piecewise-and-forward (PF) relays on Rayleigh fading channels taking the random nature of the channel variations into account. In particular, the probability density function (PDF) of the received signals at the destination of the considered multiple PF relay network is derived for the case of Rayleigh fading. The PDF is then used to support the maximum likelihood detection at the destination. Simulation results are provide to compare the bit error rate (BER) performance of the PF protocol in a multiple relay network with the performance of the amplify-and-forward (AF), decode-and-forward (DF), and estimate-and-forward (EF) protocols on Rayleigh fading as well as additive white Gaussian noise (AWGN) channels. The results indicate that the PF protocol outperforms the EF protocol in the low signal-to-noise ratio (SNR) regime while it is slightly inferior to the EF protocol for high SNR. This behavior is more pronounced over Rayleigh fading compared to AWGN.

  • 54.
    Gholamzadeh Shirmohammadi, Bamshad
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Relationships between Quality of experience and TCP flag ratios for web services2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Context: Nowadays one of the most beneficial business in IT area is web services with huge amount of users. The key ofsuccess in these type of services is flexibility in terms of providing same quality of services (QoS) and ability of fasttroubleshooting when number of users increase rapidly. To achieve these targets, evaluation of the user satisfaction is highlyessential. Moreover it is required to link user dissatisfaction to QoS parameters in terms of troubleshooting.

    Objectives: The main aim the research is to find an intelligent method for evaluation of the user satisfaction. The method isproposed to estimate quality-of-experience (QoE) without asking users to send their feed back. Connecting to this aim, thesecond target is finding the definition of function in equations of QoS=function(QoE). And finally, comparison of theimpact of QoS parameters on mobile application users and web site users is the last objective.

    Methods: For this research a web-server for video sharing propose is designed. The users can use it via web site or anAndroid mobile application. The three main QoS parameters (Packet-loss, delay and throughput) are changed gradually. Theusers are asked to score the mobile application and web site at the same time. In parallel the traffic of web-server is capturedand analyzed. Then based on variations in mean opinion scores (MOS) and also changes in TCP flags, the proper patternsfor each of the QoS parameters is provided. In this part the QoE is linked to transport layer. For the second objective, theQoE is directly linked to QoS. On the other words the graphs with QoE as horizontal axis and one of the QoS parameters asvertical axis are provided. And finally based on the gradient of these trends, the amount of impact of QoS parameters onmobile application users and web site users is compared.

    Results: Based on the results of the research, decrement in SYN and FIN flags and increment in ACK is an alarm for downgoing user satisfaction. In this situation, the problem is belongs to packet-loss. Increasing in the percentage of SYN is alsoa signal for user dissatisfaction. In this case, the problem is result of delay. And finally if the web-server problem is aboutthroughput then, SYN, FIN and ACK has up going trends. In all of the cases the rest of TCP flags has not clear up going ordecreasing trend.The correlation between QoS and QoE is formulated. The trends of MOS relative to QoS parameters for mobile phone andlaptop are very similar in case of packet-loss. For throughput the mobile phone users are a little more sensitive. The mostsignificant difference between the MOS values for mobile application and web site is belongs to delay. The increment indelay has really big negative effect on mobile application users.

    Conclusion: The final method for user satisfaction evaluation is based on the way of variations in the TCP flags. Among allthe flags, SYN, FIN and ACK passed the criteria to make the patterns. Moreover the method indicate the problem isbelongs to which of the QoS parameters. The correlation between QoE and QoS is formulated. And finally according tothese formulas, two separate web-servers for mobile application and web site is recommended.

  • 55.
    Godavarthi, Nandini Chowdary
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Power Consumption Models for Streaming on Mobile Terminals with On-Off Characteristics2016Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The usage of smartphones has been increasing with surprising speed. These smartphones are popular for delivery of video content. The main drawbacks of these smartphones are battery life and video freezing. Despite, while streaming a video it consumes large of amount of power affecting QoE. So, in this case we considered streaming a video from server to mobile client involving ONOFF characteristics. While streaming, there exists some transition delay while switching the power states and the effect of these transition delays might affect instantaneous power consumption of the smartphone.

    Henceforth, this thesis aims to determine the effect on instantaneous power consumption from distributed state durations and transitions in exponential fluid flow model, for a streamed video. Power measurements along with ON and OFF times were measured with the help of a benchmark tool, Monsoon Power Monitor tool. VLQoE tool, a video streaming tool was used to present a two state model based on the inter-picture time, for the HTTP-based video streaming. Experiments were executed in a closed enclosure setup using a black-box to avoid external obstacles that might possibly affect the power consumption metrics. Considering these measurements, the effect on instantaneous power consumption stemming from the exponentially distributed state durations and transitions in the corresponding fluid flow model can be determined and modelled. 

  • 56.
    Grandhi, Veera Venkata Santosh Surya Ganesh
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    On the Quality of Service of mobile cloud gaming using GamingAnywhere2016Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    In the recent years, the mobile gaming has been tremendously increased because of its enormous entertainment features. Mobile cloud gaming is a promising technology that overcomes the implicit restrictions such as computational capacity and limited battery life. GamingAnywhere is an open source cloud gaming system which is used in this thesis to measure the Quality of service of mobile cloud gaming. The aim of the thesis is to measure the QoS used in GamingAnywhere for mobile cloud gaming. Games are streamed from the server to the mobile client. In our study, QoS is measured using Differentiated Service (DiffServ) architecture for the traffic shaping. The research method is carried out using an experimental testbed. Dummynet is used for traffic shaping. Performance is measured in terms of bitrate, packet loss, jitter, and frame rate. Different resolutions of the game are considered in our empirical research and our results show that the framerate and bitrate have increased with the impact of network delay.

  • 57.
    Guduru, Manish Reddy
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Investigating the effects of load on the XIFI node2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Having a good understanding of the load requirements in the datacenter improves the capability to effectively provision the resources available to the meet the demands and objectives of application services. Especially in a large project like XIFI this aspect becomes even more critical because of the limited availability of the resources and the complexity of the various entities present.In this study we frame a structure that provides deep insights to comprehend XIFI infrastructure. Further, we model the user requests that approach the node for resource allocation to run their applications. We aim to provide an understanding on different aspects involved in modelling. The objective of this present study is to investigate the effect of load on the XIFI node. To achieve this objective, we model the XIFI node by examining the various entities involved in it. Furthermore, we provide an overview about what constitutes as load in the XIFI node.We conduct a detailed specifications study after which we identify the imperative entities required for the modelling of both the XIFI node and the requests. We examine the model by simulating it in CloudSim for two different scenarios varying the specifications.We simulated the designed structure for 30 iterations and analyzed 10,000 user requests for two cases where total RAM of the node is increased in the second case when compared to the first case. We analyze the CPU usage, RAM usage, Bandwidth usage and Storage usage in both the cases and examine the effects of the user requests on each one of them.The results provided evidence that the load indices on the host are dependent on each other. Also, it showed that the request modelling had an impact on the load of the host. It can also be concluded that the resource provisioning can be effective if the user behavior is known.

  • 58.
    Gunnarsson, Jim
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    GPS-­baserad virtuell geografisk inhägnad för mobil enhet2012Självständigt arbete på grundnivå (kandidatexamen)Studentuppsats (Examensarbete)
    Abstract [sv]

    The aim of this paper is to find an algorithm to establish and maintain a virtual enclosure around a mobile unit. The area may take any form and should be scalable up to and including national borders. The enclosure is managed on the mobile unit. The target system is Android. Smartphones, tablets and more recently, cameras is examples of mobile units. A modern mobile unit is part of a computer network. It is designed to be connected all the time. A mobile unit have the capability to handle large volumes of data, data that might be both sensitive and possess an economic value. Management of mobile units is vital to protect the data and insure security for the entire network. A mobile unit is a resource in the network. Each resource is defined by a set of parameters. One parameter that make a mobile unit special is the lack of physical boundaries to world. Typically, the first step in security is access control to resources. Therefore, the lack of physical access control has to be replaced by other means such as tracking the location of the mobile unit. In this paper I have studied the possibility of creating a virtual fence around the mobile unit. The mobile unit is free to move within the area enclosed by the virtual fence. The mobile unit alert all concerned parties if it crossed the fence and thus leave the enclosed area. The aim was to find a practical algorithm to establish and maintain a virtual fence around the mobile device. A grid-based algorithm was selected because it can handle small to very large areas. All data are collected in a table which makes the algorithm fast, regardless the size of the area. A grid enables management of multiple enclosures and relationships between them. Deeper analysis revealed that the mobile device is not able to position sufficiently often and accurately for the grid-based algorithm to handle small areas. A complementary method is needed for minimizing the need for positioning. To manage properties, such as geographical information, the selected algorithm is deemed to be well suited.

  • 59.
    Guo, Yang
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kreativa teknologier.
    Yao, Yong
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Bai, Guohua
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kreativa teknologier.
    On Enhancement of Inter-Activity for Knowledge Sharing in eHealth2016Ingår i: 2016 INTERNATIONAL CONFERENCE ON COMMUNICATIONS (COMM 2016), IEEE, 2016, s. 247-250Konferensbidrag (Refereegranskat)
    Abstract [en]

    Today, knowledge sharing raises as an important issue that challenges for the eHealth management system. It becomes one of the most demanding applications with references to the dynamic inter-activities among different health actors and the complex data structures involved in this application. In this paper, we suggest an activity theory based ontology model to scientifically represent various health actors in the eHealth system. The goal of the suggest model is to enhance the inter activities among these health actors for the efficient knowledge sharing purposes. We also develop a prototype software system based on the suggested ontology model. The survey results collected from the system users show the feasibility of the developed software system.

  • 60.
    Gurramkonda, Reddy Kamal Teja
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Performance Analysis on Dynamic VLAN an OpenFlow2015Självständigt arbete på avancerad nivå (magisterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    In the current innovative network, to cope with the increased require-

    ments of customers, there is a rapid increase in the development of dierent

    protocols and applications. With such increase in networking technology,

    the security constraints are becoming more and more severe, reducing the

    accessibility to the actual network for implementing new protocols. This

    scenario forced for an urgent need of a technology, which can help the re-

    searchers to implement their developed protocols in the network without

    inuencing the production trac. This need resulted in a concept called

    network isolation. This is achieved by VLAN or SDN technologies.

    In this study, we investigate the performance of VLAN and an API

    of SDN in the context of establishing dynamic link, in switching setup. For

    such a link creation, dynamic VLAN (dVLAN) is used in the former case

    and OpenFLow protocol is used in the later scenario. The main focus in this

    study is to compare the dynamic behavior of both the protocols in layer-2

    context by measuring network level performance metrics of each protocol.

    Some of the features like, vendor independency and software independency

    is taken into account while measuring the performance metrics.

    In order to evaluate the performance, an experimental testbed is

    implemented. The network level performance metric called protocol setup

    time is measured. It is the time taken by each protocol to setup an active

    link between two end-hosts. A two-tire network architecture is implemented

    with the mentioned features.

    From the analytical and statistical results obtained, OpenFlow re-

    sulted in performing relatively better when compared to dynamic VLANs.

    By carefully examining the protocol setup time of OpenFlow against dVLAN,

    OpenFlow took less time when compared to dVLAN resulting in faster exe-

    cution in enabling connectivity. On the other hand, the analytical study on

    the two protocols reects the simplicity exhibited by dVLAN over Open-

    Flow.

  • 61. Ha, Dac-Binh
    et al.
    Duong, Trung Q.
    Tran, Duc-Dung
    Zepernick, Hans-Jürgen
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Vu, Truong Tien
    Physical Layer Secrecy Performance over Rayleigh/Rician Fading Channels2014Ingår i: International Conference on Advanced Technologies for Communications, Hanoi, Vietnam: IEEE , 2014, Vol. Article number 7043367, s. 113-118Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we investigate the physical layer secrecy performance of a single-input single-output system that consists of single antenna devices and operates in the presence of a single antenna passive eavesdropper over dissimilar fading channels. In particular, we consider two scenarios in terms of dissimilar fading channel arrangements: 1) The legal/illegal channels are subject to Rayleigh/Rician fading, respectively; 2) The legal/illegal channels are subject to Rician/Rayleigh fading, respectively. Specifically, analytical expressions for the probability of the existence of a non-zero secrecy capacity and the secrecy outage probability are derived by using statistical characteristics of the signal-to-noise ratio. Numerical results are provided for selected scenarios to illustrate applications of the developed analytical expressions.

  • 62. Han, Guangjie
    et al.
    Shen, Wen
    Duong, Quang Trung
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Guizani, Mohsen
    Hara, Takahiro
    A proposed security scheme against denial of service attacks in cluster-based wireless sensor networks2014Ingår i: Security and Communication Networks, ISSN 1939-0114, E-ISSN 1939-0122, Vol. 7, nr 12, s. 2542-2554Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Traditional security schemes developed for sensor networks are not suitable for cluster-based wireless sensor networks (WSNs) because of their susceptibility to Denial of Service (DoS) attacks. In this paper, we provide a security scheme against DoS attacks (SSAD) in cluster-based WSNs. The scheme establishes trust management with energy character, which leads nodes to elect trusted cluster heads. Furthermore, a new type of vice cluster head node is proposed to detect betrayed cluster heads. Theoretical analyses and simulation results show that SSAD can prevent and detect malicious nodes with high probability of success

  • 63. Han, Guangjie
    et al.
    Shen, Wen
    Duong, Trung Q.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Guizani, Mohsen
    Hara, Takahiro
    A proposed security scheme against Denial of Service attacks in cluster-based wireless sensor networks2014Ingår i: SECURITY AND COMMUNICATION NETWORKS, ISSN 1939-0114, Vol. 7, nr 12, s. 2542-2554Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Traditional security schemes developed for sensor networks are not suitable for cluster-based wireless sensor networks (WSNs) because of their susceptibility to Denial of Service (DoS) attacks. In this paper, we provide a security scheme against DoS attacks (SSAD) in cluster-based WSNs. The scheme establishes trust management with energy character, which leads nodes to elect trusted cluster heads. Furthermore, a new type of vice cluster head node is proposed to detect betrayed cluster heads. Theoretical analyses and simulation results show that SSAD can prevent and detect malicious nodes with high probability of success

  • 64.
    Haque, Md. Emdadul
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Design of a Self-sufficient Micro-Grid with Renewable Energy Production.2013Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    In power development technology there are pioneering various μ-grid concepts, that integrating multiple distributed power generation sources into a small network serving some or all of the energy needs of participating users can provide benefits including reduced energy costs, increased overall energy efficiency and improved environmental performance and local electric system reliability. In the fast progression of technology the electric vehicles, electric construction equipment and machinery such as- road building or quarries would greatly benefited from electrification and the by this revolutions, they able defending the environment from detrimental effect and potential energy (and local emission) reduction is sufficient. These types of sites are often remotely located and it is much costly to meet the high voltage utility grid or distribution grid, which are normally far-off from the sites. Hence, it would be advantageous to be able to set up such sites without having to build long and expensive connections to high voltage transmission and distribution grids. In this project we have design and proposed a self-sufficient smart DC micro-grid providing renewable energy resources to supply electric machinery is designed. This grid is capable of meeting energy as well as peak power demands of machine site while offering the possibility to fully rely on locally produced renewable energy. In this project we have included price and performance forecasting for solar and wind energy, charger, grid energy storage system and micro-grid power electronics. Therefore, with this design it is capable to provide efficient power supply to the site and can meet the demand at peak loads. Grid modeling and simulating results (including loads, storage and energy production) are done by MATLAB.

  • 65.
    Harshini, Nekkanti
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Measuring And Modeling Of Open vSwitch Performance: Implementation in Docker2016Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Network virtualization has become an important aspect of the Telecom industry. The need forefficient, scalable and reliable virtualized network functions is paramount to modern networking.Open vSwitch is such virtual switch that attempts to extend the usage of virtual switches to industrygrade performance levels on heterogeneous platforms.The aim of the thesis is to give an insight into the working of Open vSwitch. To evaluate theperformance of Open vSwitch in various virtualization scenarios such as KVM (second companionthesis)[1] and Docker. To investigate different scheduling techniques offered by the Open vSwitchsoftware and supported by the Linux kernel such as FIFO, SFQ, CODEL, FQCODEL, HTB andHFSC. To differentiate the performance of Open vSwitch in these scenarios and scheduling capacitiesand determine the best scenario for optimum performance.The methodology of the thesis involved a physical model of the system used for real-timeexperimentation as well as quantitative analysis. Quantitative analysis of obtained results paved theway for unbiased conclusions. Experimental analysis was required to measure metrics such asthroughput, latency and jitter in order to grade the performance of Open vSwitch in the particularvirtualization scenario.The results of the thesis must be considered in context with a second companion thesis[1]. Both thethesis aim at measuring the performance of Open v-Switch but the virtualization scenarios (Dockerand KVM) which are chosen are different, However, this thesis outline the performance of Open vSwitch and linux bridge in docker scenario. Various scheduling techniques were measured fornetwork performance metrics across both Docker and KVM (second companion thesis) and it wasobserved that Docker performed better in terms of throughput, latency and jitter. In Docker scenarioamongst the scheduling algorithms measured, it has almost same throughput in all schedulingalgorithms and latency shows slight variation and FIFO has least latency, as it is a simplest algorithmand consists of default qdisk. Finally jitter also shows variation on all scheduling algorithms.The conclusion of the thesis is that the virtualization layer on which Open vSwitch operates is one ofthe main factors in determining the switching performance. The KVM scenario and Docker scenarioeach have different virtualization techniques that incur different overheads that in turn lead to differentmeasurements. This difference occurs in different packet scheduling techniques. Docker performsbetter than KVM for both bridges. In the Docker scenario Linux bridge performs better than that ofOpen vSwitch, throughput is almost constant and FIFO has a least latency amongst all schedulingalgorithms and jitter shows more variation in all scheduling algorithms.

  • 66.
    Hobring, Linus
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Söderberg, Philip
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    A sensor network for the Internet of Things Integrated with a bidirectional backend2014Studentuppsats (Examensarbete)
    Abstract [en]

    Internet of Things is rapidly evolving. This thesis includes a study of single-board computers suitable for machine-to-machine communication together with the developing process of a sensor network integrated with a bidirectional communication platform. Raspberry Pi was selected as the single-board computer used in the proposed system. The Message Queuing Telemetry Transport protocol was selected as main communication protocol to handle all exchange of information between the network and the bidirectional communication platform. It was selected because of its reliability, low bandwidth and publish/subscribe architecture. Decision-making procedures were implemented to work with both local sensor data and data from different Message Queuing Telemetry Transport streams, such as GPS data, used to calculate the distance between the user’s smart phone and the office to prepare the workstation, temperature sensors and ambient light sensors controlling Philips HUE light bulbs. The finished sensor network was design to work within office environments to prepare workstations and monitor the work climate. The number of sensors connected to the single-board computer has a major impact in the CPU usage. Measurements and calculations show that 17 connected physical sensors will cause a CPU usage of 96%.

  • 67.
    Holmberg, Johan
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Sårbarhetsanalys på dricksvattenanläggningar2014Studentuppsats (Examensarbete)
    Abstract [en]

    Vatten är ett av våra viktigaste livsmedel, utan vatten klarar vi människor oss inte särskilt länge. Trots detta är hotbilden och framför allt konsekvenserna av en attack mot dricksvattenförsörjningen i Sverige något som inte är riktigt uppmärksammat. Eftersom själva processen av att producera samt leverera drickbart vatten till befolkningen sträcker sig över ett stort geografisk område, finns ofta många sårbara punkter som är spridda över ett stort område. Säkerhetsarbetet är därför av högsta vikt. I detta arbete presenteras en sårbarhetsanalys på skalskyddet på tre anläggningar som tillhör ett kommunalägt företag som producerar och levererar dricksvatten. Metoden används är ett attackträd, som går ut på att identifiera alla möjliga angreppsmöjligheter och utefter resultat ta fram eventuella åtgärdsförslag som kan öka säkerhetsnivån ytterligare. I avhandlingen ingår även en undersökning av hur företagets ägarkommuner bedriver sitt säkerhetsarbete. Undersökningen har gjort genom en enkätundersökning som säkerhetschefer/säkerhetssamordnare och VA ansvariga har svarat på för sin kommuns räkning.

  • 68. Hossfeld, Tobias
    et al.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    The unexpected QoE killer: When the network emulator misshapes traffic and QoE2015Ingår i: 2015 7th International Workshop on Quality of Multimedia Experience, QoMEX 2015, IEEE Communications Society, 2015, Vol. Article number 7148093Konferensbidrag (Refereegranskat)
    Abstract [en]

    Packet streams observed in today’s networks show a high degree of autocorrelation as successive packets tend to exhibit similar delay and loss characteristics. Network emulators used to conduct performance evaluations therefore have to support the generation of such autocorrelated streams. Typically, this is done using first order autoregressive processes. In this paper, we show that a common implementation of this approach leads to problems when emulating correlated packet loss, and therefore possibly produces erroneous results and conclusions when evaluating objectively application quality or QoE in subjective studies. Further typical network emulator implementations make even low packet jitter become an unexpected QoE killer. © 2015 IEEE.

  • 69.
    Huu, Tung Pham
    et al.
    NUCE, Fac Informat Technol., VNM.
    Quach, Truong Xuan
    TNU Univ Informat & Commun Technol. VNM.
    Tran, Hung
    Malardalen Univ., SWE.
    Zepernick, Hans-Juergen
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Sibomana, Louis
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    On Proactive Attacks for Coping With Cooperative Attacks in Relay Networks2017Ingår i: 2017 23RD ASIA-PACIFIC CONFERENCE ON COMMUNICATIONS (APCC): BRIDGING THE METROPOLITAN AND THE REMOTE, 2017, s. 220-225Konferensbidrag (Refereegranskat)
    Abstract [en]

    Cooperative communications in which relays assist the transmission of signals from source to destination offer extended radio coverage and improved link reliable. However, transmitting signals with the help of a relay network may also open additional avenues for eavesdropper to overhear confidential information. Further, as jammers and eavesdroppers may cooperate to attack the relay network, offering secure communications becomes a challenging problem. To cope and reduce the effect of such cooperative attacks, we propose a proactive attack scheme in which the legitimate users generate jamming signals in an attempt to counteract such hostile cooperative attacks. In order to assess the security performance of the proactive attack scheme compared to a non-protection scheme, an analytical expression of the secrecy outage probability is derived. Numerical results for different system settings are provided showing that the proactive attack scheme can indeed significantly improve the security performance of the considered relay networks.

  • 70.
    Höglund, Markus
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Lavhammar, Mikael Ljungqvist
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Säkerhetsutredning av Karlskrona Skärgårdsfest2014Studentuppsats (Examensarbete)
    Abstract [en]

    Syftet med arbetet var att förbättra säkerhetsarbetet åt Karlskrona Skärgårdsfest 2014. Första gången eventet hölls, 2013, nådde det stora framgångar och med ett större säkerhetstänkande kommer de efterföljande eventen bli ännu bättre. För att nå dit har vi bland annat använt oss av ett MTO-perspektiv och sårbarhetsanalys, för att effektivt hitta säkerhetsbrister gällande både organisationen och själva eventet på Karlskrona Skärgårdsfest 2013. Genom vårt researcharbete fann vi att Östersjöfestivalen i Karlshamn, hade en säkerhetsarbetsgrupp. De gör årliga scenarioanalyser. Frågan vi ställde oss i ett tidigt stadium var ”Behöver Karlskrona Skärgårdsfest en liknande säkerhetsarbetsgrupp?”. Under arbetets gång blev det mer och mer tydligt att en sådan arbetsgrupp behövs. Det kom att bli det viktigaste åtgärdsförslaget, för att få en organiserad och strukturerad säkerhetsgrund. Där kan medarbetarna tillsammans arbeta mot samma uppsatta visioner och mål. För att få praktisk och teoretisk kunskap har vi gjort en riskanalys med samma verktyg som förslagsvis den nya säkerhetsgruppen kan använda sig av. I riskanalysen fokuserade vi på besökarnas trygghet och evenemangets varumärke. Vi har även avgränsat oss i vår analys till de specifika centrala platserna för eventet som är: Stortorget, Hoglands park och Fisktorget. Då det finns flera områden inom Karlskrona Skärgårdsfests ram som vi inte berört. Kan andra självklart genomföra riskanalyser på andra delar av evenemanget, t.ex. kan man analysera skärgårdstrafiken med alla båtturer. En annan viktigt aspekt att poängtera är att vårt projektarbete kan användas som en förstudie för både kunden, kommunen och eventuellt andra högskolestudenter, för att vidareutveckla vårt arbete och kontinuerligt upprätthålla säkerhetsarbetet. Eftersom en riskanalys aldrig blir komplett, bör nya analyser göras mellan varje Skärgårdsfest. Vi skickade i början av vårt arbete ut en enkät med frågor som berörde säkerhet och säkerhetsarbete till fem andra stadsfesterna/festivalerna i Götaland. Deras svar var till stor hjälp i vårt arbete med att ta fram anpassade åtgärdsförslag till Karlskrona Skärgårdsfest 2014. Vår vision med det var att stärka Karlskrona Skärgårdsfests varumärke, och främja besökarnas trygghet och upplevelser. De potentiella risker och åtgärdsförslag vi tog fram i denna rapport, hoppas vi kan hjälpa till i arbetet med att stärka eventet så det kan bli en förebild för andra evenemang och stadsfester i Sverige och deras säkerhetsarbete. Samtidigt som vi vill att Karlskrona Skärgårdsfest ska bli så framgångsrik som möjligt.

  • 71.
    Ickin, Selim
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Quality of Experience on Smartphones: Network, Application, and Energy Perspectives2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Smartphones have become crucial enablers for users to exploit online services such as learning, leisure, communicating, and socializing. The user-perceived quality of applications and services is an important factor to consider, in order to achieve lean resource management, to prevent user churn and revenue depletion of service or network providers. This is often studied within the scope of Quality of Experience (QoE), which has attracted researchers both in academia and industry. The objective of this thesis is to study the most important factors influencing QoE on smartphones and synthesize solutions for intervention. The temporal impairments during a real-time energy-hungry video streaming are studied. The aim is to quantify the influence of temporal impairments on the user-perceived video QoE at the network and application level together with energy measurements, and also to propose solutions to reduce smartphone energy consumption without degrading the user’s QoE on the smartphone for both user-interactive, e.g., video, and non-interactive cases. QoE measurements on smartphones are performed throughout in-the-wild user studies. A set of quantitative Quality of Experience (QoE) assessment tools are implemented and deployed for automatic data logging at the network- and application-level. Online momentary survey, Experience Sampling Method (ESM) software, and Day Reconstruction Method (DRM) along weekly face-to-face user interviews are employed. The subjective QoE is obtained through qualitative feedback including Mean Opinion Score (MOS) as well as in-situ indications of poor experiences by users. Additionally, energy measurements on smartphones are conducted in controlled-lab environment with the Monsoon device. The QoE of smartphone applications and services perceived by users depends on many factors including anomalies in the network, application, and also the energy consumption. At the network-level, high packet delay variation causes long video freezes that eventually impact negatively the end-user perceived quality. The freezes can be quantified as large time gaps in-between the displayed pictures during a video stream at the application-level. We show that the inter-picture time in cellular-based video stream can be represented via two-state exponential ON/OFF models. We show models representing the non-linear relationship between the QoE and the mean inter-picture time. It is shown that energy measurements help to reveal the temporal impairments in video stream enabling energy consumption as a QoE indicator. Next, energy waste and saving during temporal impairments are identified. Additionally, other video streaming use cases, e.g., “download first and watch later”, are studied and appropriate energy-saving download scheduling mechanisms are recommended. The possibility for decreasing energy consumption when the smartphone screen is OFF, while maintaining QoE, is revealed. We first show exponential models to represent user’s interaction with smartphone, then propose a NyxEnergySaver software, to control the cellular network interface in a personalized manner to save smartphone energy. According to our findings, more than 30% smartphone energy can be saved without impacting the user-perceived QoE.

  • 72.
    Ickin, Selim
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Wac, Katarzyna
    Arlos, Patrik
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Temiz, Canberk
    Mkocha, Khadija
    VLQoE: Video QoE instrumentation on the smartphone2015Ingår i: Multimedia tools and applications, ISSN 1380-7501, E-ISSN 1573-7721, Vol. 74, nr 2, s. 381-411Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The usage of network-demanding applications is growing rapidly such as video streaming on mobile terminals. However, network and/or service providers might not guarantee the perceived quality for video streaming that demands high packet transmission rate. In order to satisfy the user expectations and to minimize user churn, it is important for network operators to infer the end-user perceived quality in video streaming. Today, the most reliable method to obtain end-user perceived quality is through subjective tests, and the preferred location is the user interface as it is the closest point of application to the end-user. The end-user perceived quality on video streaming is highly influenced by occasional freezes; technically the extraordinary time gaps between two consecutive pictures that are displayed to the user, i.e., high inter-picture time. In this paper, we present a QoE instrumentation for video streaming, VLQoE. We added functionality to the VLC player to record a set of metrics from the user interface, application-level, network-level, and from the available sensors of the device. To the best of our knowledge, VLQoE is the first tool of its kind that can be used in user experiments for video streaming. By using the tool, we present a two state model based on the inter-picture time, for the HTTP- and RTSP-based video streaming via 3.5G. Next, we studied the influence of inter-picture time on the user perceived quality through out a user study. We investigated the minimum user perceived inter-picture time, and the user response time.

  • 73.
    Ickin, Selim
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Zinner, Thomas
    Wac, Katarzyna
    Fiedler, Markus
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Catching the download train: Energy-efficient file downloading on smartphones2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    The most energy-consuming applications in battery life-constrained smartphones are the ones that comprise data transmission, especially via the 3G interface. Scheduling download activities on smartphones is especially necessary, if there are multiple asynchronous downloads scattered over a long duration. The latter scenario highly increases the energy consumption of smartphones. In this paper, we investigate energy consumption with the focus on file downloading while scheduling multiple file downloads in two scenarios: serialized and parallel. We repeat the experiments on a single smartphone via its 3G and also via WiFi tethering via another smartphone. We assess the performance of the two scenarios via measurement of power consumption and corresponding download duration in a realistic environment.

  • 74.
    Ilie, Dragos
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Datta, Vishnubhotla Venkata Krishna Sai
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för datalogi och datorsystemteknik.
    On Designing a Cost-Aware Virtual CDN for the Federated Cloud2016Ingår i: 2016 INTERNATIONAL CONFERENCE ON COMMUNICATIONS (COMM 2016), IEEE, 2016, s. 255-260Konferensbidrag (Refereegranskat)
    Abstract [en]

    We have developed a prototype for a cost-aware, cloud-based content delivery network (CDN) suitable for a federated cloud scenario. The virtual CDN controller spawns and releases virtual caching proxies according to variations in user demand. A cost-based heuristic algorithm is used for selecting data centers where proxies are spawned. The functionality and performance of our virtual CDN prototype were evaluated in the XIFI federated OpenStack cloud. Initial results indicate that the virtual CDN can offer reliable and prompt service. Multimedia providers can use this virtual CDN solution to regulate expenses and have greater freedom in choosing the placement of virtual proxies as well as more flexibility in configuring the hardware resources available to the proxy (e.g., CPU cores, memory and storage).

  • 75.
    Irshad, Azeem
    et al.
    Int. Islamic Univ., PAK.
    Sher, Muhammad
    Int. Islamic Univ., PAK.
    Nawaz, Omer
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Chaudhry, Shehzad Ashraf
    Int. Islamic Univ., PAK.
    Khan, Imran
    Int. Islamic Univ., PAK.
    Kumari, Saru
    Chaudhary Charan Singh Univ, IND.
    A secure and provable multi-server authenticated key agreement for TMIS based on Amin et al. scheme2017Ingår i: Multimedia tools and applications, ISSN 1380-7501, E-ISSN 1573-7721, Vol. 76, nr 15, s. 16463-16489Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The security for Telecare Medicine Information Systems (TMIS) has been crucial for reliable dispensing of the medical services to patients at distant locations. Security and privacy element needs to be there for any physician or caregiver to make certain an appropriate diagnosis, medical treatment or any other exchange of critical information. In this connection, many relevant TMIS-based authentication schemes have been presented, however various forms of attacks and inefficiencies render these schemes inapplicable for a practical scenario. Lately, Amin et al. proposed a scheme based on a multi-server authentication for TMIS. However, the Amin et al., scheme has been found vulnerable to user and server impersonation attacks. We have proposed an improved model with higher performance and efficiency, as evident from the forthcoming sections. Besides, the scheme has been backed up by formal security analysis using BAN logic to ensure the resilience of the proposed scheme.

  • 76.
    Islam, Nazrul
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Elepe, Vijaya John David
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    The Impact of Waiting Time Distributions on QoE of Task-Based Web Browsing Sessions2014Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    There has been an enormous growth in the Internet usage in recent years, fueled by the increasing number of multimedia applications and widespread availability of World Wide Web (WWW). The end-user generally accesses these applications through web browsing activities. These time-critical services often suffer from the delays ranging from small chunks to long peaks which can have severe implications on the Quality of Experience (QoE). Hence, it is worthwhile to identify the impact of different variations of delay on the end-user QoE. This research focused on the end-user QoE for three different distributions of delays occurring during an e-commerce shopping experiment. By keeping the overall waiting time of every sessions same, the study shows that the end-user QoE is different for different variety of delays. And the research also concludes that, the users prefer small frequently occurring delays as compared to the long rarely occurring delays within a task-driven web browsing session.

  • 77.
    Islam, Nazrul
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Elepe, Vijaya John David
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Shaikh, Junaid
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    In Small Chunks or All at Once? User Preferences of Network Delays in Web Browsing Sessions2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    The time-critical tasks on the Internet are increasing. The delays in these tasks can have severe implications on the Quality of Experience (QoE) of a service. Therefore, networks require smart user-centric resource management mechanisms to reduce the impact of these delays on QoE. For this, a better understanding of the user preferences with regards to service performance is a prerequisite. In this paper, we present user responses to the three different distributions of delays, occurring during shopping sessions on the Web. By keeping the overall waiting time of the sessions same, we show how the users respond differently to the different set of delays. We analyzed the user responses and found that, the users prefer small frequently occurring delays as compared to the long rarely occurring delays within a task-based session.

  • 78.
    Jamil, Momin
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Zepernick, Hans-Jürgen
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Sequence Design for Radar Applications Using Particle Swarm Optimization2016Ingår i: PROCEEDINGS OF THE 2016 INTERNATIONAL CONFERENCE ON ADVANCED TECHNOLOGIES FOR COMMUNICATIONS (ATC), IEEE, 2016, s. 210-214Konferensbidrag (Refereegranskat)
    Abstract [en]

    Performance of polyphase sequences in radar applications can be evaluated using measures including autocorrelation function, integrated sidelobe ratio (ISLR), and peak-tosidelobe ratio (PSLR). In this paper, we adopt particle swarm optimization to find optimal parameters of Oppermann sequences such that sequences with optimal ISLR and PSLR are generated. This class of sequences has been chosen as it allows to design for a wide range of correlation characteristics by essentially controlling three parameters. A sequence design example is provided in order to illustrate that particle swarm optimization is indeed well-suited to produce optimal sequence designs with respect to the considered performance measures.

  • 79.
    Jamil, Momin
    et al.
    Harman/Becker Automotive Systems, DEU.
    Zepernick, Hans-Jürgen
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Yang, Xinshe
    Middlesex University, GBR.
    Multimodal function optimization using an improved bat algorithm in noise-free and noisy environments2017Ingår i: Modeling and Optimization in Science and Technologies, Springer, 2017, 10, s. 29-49Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Modern optimization problems in economics, medicine, and engineering are becoming more complicated and have a convoluted search space with multiple minima. These problems are multimodal with objective functions exhibiting multiple peaks, valleys, and hyperplanes of varying heights. Furthermore, they are nonlinear, non-smooth, non-quadratic, and can have multiple satisfactory solutions. In order to select a best solution among several possible solutions that can meet the problem objectives, it is desirable to find many such solutions. For these problems, the gradient information is either not available or not computable within reasonable time. Therefore, solving such problems is a challenging task. Recent years have seen a plethora of activities to solve such multimodal problems using non-traditional methods. These methods are nature inspired and are becoming popular due to their general applicability and effective search strategies. In this chapter, we assess the ability of an improved bat algorithm (IBA) to solve multimodal problems in noise-free and additive white Gaussian noise (AWGN) environments. Numerical results are presented to show that the IBA can successfully locate multiple solutions in both noise-free and AWGN environments with a relatively high degree of accuracy. © Springer International Publishing AG 2017.

  • 80. Jamil, Momin
    et al.
    Zepernick, Hans-Jürgen
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Yang, Xin-She
    Synthesizing Cross-Ambiguity Functions Using An Improved Bat Algorithm2015Ingår i: Recent Advances in Swarm Intelligence and Evolutionary Computation / [ed] Yang, Xin-She, Berlin: Springer , 2015Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    The cross-ambiguity function (CAF) relates to the correlation processing of signals in radar, sonar, and communication systems in the presence of delays and Doppler shifts. It is a commonly used tool in the analysis of signals in these systems when both delay and Doppler shifts are present. In this chapter, we aim to tackle the CAF synthesization problem such that the synthesized CAF approximates a desired CAF. A CAF synthesization problem is addressed by jointly designing a pair of waveforms using a metaheuristic approach based on the echolocation of bats. Through four examples, it is shown that such an approach can be used as an effective tool in synthesizing different types of CAFs.

  • 81.
    Junaid, Junaid
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Network-Based Monitoring of Quality of Experience2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The recent years have observed a tremendous shift from the technology-centric assessment to the user-centric assessment of network services. Consequently, measurement and modelling of Quality of Experience (QoE) attracted many contributions from researchers and practitioners. Generally, QoE is assessed via active and passive measurements. While the former usually allows QoE assessment on the test traffic, the latter opens avenues for continuous QoE assessment on the real traffic generated by the users. This thesis contributes towards passive assessment of QoE.

    This thesis document begins with a background on the fundamentals of network management and objective QoE assessment. It extends the discussion further to the QoE-centric monitoring and management of network, complimented by the details about QoE estimator agent developed within the Celtic project QuEEN (Quality of Experience Estimators in Network).

    The discussion on findings starts with results from subjective tests to understand the relationship between waiting times and user subjective feedback over time. These results strengthen the understanding of timescales on which users react, as well as, the effect of user memory on QoE. The findings show that QoE drops significantly when the user faces recurring waiting times of 0.5 s to 4 s durations in case of video streaming and web browsing services. With recurring network disturbances within every 8 s – 16 s time intervals, the user tolerance to waiting times decreases constantly, showing the sign of user memory of recent disturbances.

    Subsequently, this document introduces and evaluates a passive wavelet-based QoE monitoring method. The method detects timescales on which transient outages occur frequently. A study presents results from qualitative measurements, showing the ability of wavelet to differentiate on-fly between “Good” and “Bad” traffic streams. In sequel, a quantitative study systematically evaluates wavelet-based metrics. Subsequently, the subjective evaluation and wavelet analysis of 5 – 6 minutes long video streaming sessions on mobile networks show that wavelet-based metrics is indeed useful for passive monitoring of QoE issues.

    Finally, this thesis investigates a method for passive monitoring of user reactions to degrading network performance. The method is based on the TCP termination flags. With a systematic evaluation in a test environment, the results characterise termination of data transfers in case of different user actions in the web browser.

  • 82.
    Kabiri, Charles
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    On the Performance of Underlay Cognitive Radio Networks with Interference Constraints and Relaying2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Efficiently allocating the scarce and expensive radio resources is a key challenge for advanced radio communication systems. To this end, cognitive radio (CR) has emerged as a promising solution which can offer considerable improvements in spectrum utilization. Furthermore, cooperative communication is a concept proposed to obtain spatial diversity gains through relays without requiring multiple antennas. To benefit from both CR and cooperative communications, a combination of CR networks (CRNs) with cooperative relaying referred to as cognitive cooperative relay networks (CCRNs) has recently been proposed. CCRNs can better utilize the radio spectrum by allowing the secondary users (SUs) to opportunistically access spectrum, share spectrum with primary users (PUs), and provide performance gains offered by cooperative relaying. In this thesis, a performance analysis of underlay CRNs and CCRNs in different fading channels is provided based on analytical expressions, numerical results, and simulations. To allocate power in the CCRNs, power allocation policies are proposed which consider the peak transmit power limit of the SUs and the outage probability constraint of the primary network. Thus, the impact of multiuser diversity, peak transmit power, fading parameters, and modulation schemes on the performance of the CRNs and CCRNs can be analyzed. The thesis is divided into an introduction and five research parts based on peer-reviewed conference papers and journal articles. The introduction provides fundamental background on spectrum sharing systems, fading channels, and performance metrics. In the first part, a basic underlay CRN is analyzed where the outage probability and the ergodic capacity of the network over general fading channels is derived. In the second part, the outage probability and the ergodic capacity of an underlay CRN are assessed capturing the effect of multiuser diversity on the network subject to Nakagami-m fading. Considering the presence of a PU transmitter (PU-Tx), a power allocation policy is derived and utilized for CRN performance analysis under Rayleigh fading. In the third part, the impact of multiple PU-Txs and multiple PU receivers (PU-Rxs) on the outage probability of an underlay CCRN is studied. The outage constraint at the PU-Rx and the peak transmit power constraint of the SUs are taken into account to derive the power allocation policies for the SUs. In the fourth part, analytical expressions for the outage probability and symbol error probability for CCRNs are derived where signal combining schemes at the SU receiver (SU-Rx) are compared. Finally, the fifth part applies a sleep/wake-up strategy and the min(N; T) policy to an underlay CRN. The SUs of the network operate as wireless sensor nodes under Nakagami-m fading. A power consumption function of the CRN is derived. Further, the impact of M/G/1 queue and fading channel parameters on the power consumption is assessed.

  • 83.
    Kabiri, Charles
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Sibomana, Louis
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Zepernick, Hans-Jürgen
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Symbol Error Probability and Effective Capacity of an Underlay CRN over alpha-mu Fading Channels2015Ingår i: 2015 9TH INTERNATIONAL CONFERENCE ON SIGNAL PROCESSING AND COMMUNICATION SYSTEMS (ICSPCS), IEEE Communications Society, 2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper analyses the performance of an underlay cognitive radio network (CRN) over alpha-mu fading channels in terms of symbol error probability (SEP) and effective capacity (EC). The alpha-mu distribution allows for a more general fading model with an increased level of generality compared to well-known models such as Nakagami-m and Rayleigh fading. The SEP and EC at the secondary user receiver are therefore evaluated for different fading parameters alpha and mu In the considered underlay CRN, the secondary user transmit power is subject to a peak interference power constraint in order to limit the interference to the primary user receiver. Given this setting, analytical expressions for the SEP and EC are derived for the general case of alpha-mu fading channels. Numerical results are provided to illustrate the performance of the considered underlay CRN on different fading channels.

  • 84.
    Kabiri, Charles
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Zepernick, Hans-Jürgen
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Hung, Tran
    On Power Consumption of Wireless Sensor Nodes with Min(N,T) Policy in Spectrum Sharing Systems2014Ingår i: IEEE Vehicular Technology Conference Proceedings, IEEE , 2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we analyze the power consumption of wireless sensor nodes with min(N, T) policy and M/G/1 queue in the presence of Nakagami-m fading. In particular, this system setting is applied to a wireless sensor node operating in a cognitive radio system as secondary user in the presence of a primary user. As such, not only the queue policy influences the power consumption but also the interference power constraint imposed on the wireless sensor node by the primary user. Thus, a queued sleep/wake-up strategy is analyzed in order to mitigate the average power consumption of a sensor node using min(N, T) policy in the context of an M/G/1 queue and a spectrum sharing environment in the presence of signal fading. Numerical examples are presented to illustrate the impact of queuing parameters and fading channel on the power consumption of a wireless sensor node.

  • 85.
    Kabiri, Charles
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Zepernick, Hans-Jürgen
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Hung, Tran
    On Power Consumption of Wireless Sensor Nodes with Min(N,T) Policy in Spectrum Sharing Systems2014Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    In this paper, we analyze the power consumption of wireless sensor nodes with min(N,T) policy and M/G/1 queue in the presence of Nakagami-m fading. In particular, this system setting is applied to a wireless sensor node operating in a cognitive radio system as secondary user in the presence of a primary user. As such, not only the queue policy influences the power consumption but also the interference power constraint imposed on the wireless sensor node by the primary user. Thus, a queued sleep/wake-up strategy is analyzed in order to mitigate the average power consumption of a sensor node using min(N,T) policy in the context of an M/G/1 queue and a spectrum sharing environment in the presence of signal fading. Numerical examples are presented to illustrate the impact of queuing parameters and fading channel on the power consumption of a wireless sensor node.

  • 86.
    Kabiri, Charles
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Zepernick, Hans-Jürgen
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Tran, Hung
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Effective capacity of cognitive cooperative relay networks over α-μ Fading channels2015Ingår i: 2015 21st Asia-Pacific Conference on Communications, APCC 2015, IEEE Press, 2015, s. 427-432, artikel-id Article number 7412551Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, the effective capacity, a link-layer model supporting Quality of Service (QoS) metrics such as user data rate, packet loss rate and service delay, is analyzed. We consider an underlay cognitive cooperative relay network (CCRN) subject to independent non-identically distributed aH fading. An analytical expression of the effective capacity is derived by means of Fox H-functions and Meijer G-functions along with the Mellin transform of the product of two H-functions. The network performance is analyzed against the QoS exponent and the peak interference power constraint imposed by primary users.

  • 87.
    Kabiri, Charles
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Zepernick, Hans-Jürgen
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Tran, Hung
    Malardalen Univ, SWE.
    Outage Probability of a Cognitive Cooperative Relay Network with Multiple Primary Users Under Primary Outage Constraint2016Ingår i: PROCEEDINGS OF THE 2016 INTERNATIONAL CONFERENCE ON ADVANCED TECHNOLOGIES FOR COMMUNICATIONS (ATC), IEEE, 2016, s. 38-42Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we consider a cognitive cooperative relay network (CCRN) that utilizes a decode-and-forward relay in the presence of multiple primary users. Given this system setting, we study the effect of multiple primary transmitters (PU-Txs) and multiple primary user receivers (PU-Rxs) on the outage probability of the considered CCRN. Specifically, power allocation policies for the secondary user transmitter (SU-Tx) and the secondary relay (SR) are formulated, subject to the outage constraint which is imposed by the PU-Rxs as well as the peak transmit power limits given at the SU-Tx and SR. On the basis of these power allocation policies for the SU-Tx and SR, an expression for the outage probability of the CCRN is derived. Numerical examples are presented to show the effect of different system parameters on the outage probability of the CCRN.

  • 88.
    Kalidindi, Rajeev varma
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Monitoring and Analysis of Disk throughput and latency in servers running Cassandra database2016Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Context. Light weight process virtualization has been used in the past e.g., Solaris zones, jails in Free BSD and Linux’s containers (LXC). But only since 2013 is there a kernel support for user namespace and process grouping control that make the use of lightweight virtualization interesting to create virtual environments comparable to virtual machines. Telecom providers have to handle the massive growth of information due to the growing number of customers and devices.

    Traditional databases are not designed to handle such massive data ballooning. NoSQL databases were developed for this purpose. Cassandra, with its high read and write throughputs, is a popular NoSQL database to handle this kind of data. Running the database using operating system virtualization or containerization would offer a significant performance gain when compared to that of virtual machines and also gives the benefits of migration, fast boot up and shut down times, lower latency and less use of physical resources of the servers.

    Objectives. This thesis aims to investigate the trade-off in performance while loading a Cassandra cluster in bare-metal and containerized environments. A detailed study of the effect of loading the cluster in each individual node in terms of Latency, CPU and Disk throughput will be analyzed. Methods. We implement the physical model of the Cassandra cluster based on realistic and commonly used scenarios or database analysis for our experiment.

    We generate different load cases on the cluster for bare-metal and Cassandra in docker scenarios and see the values of CPU utilization, Disk throughput and latency using standard tools like sar and iostat. Statistical analysis (Mean value analysis, higher moment analysis, and confidence intervals) are done on measurements on specific interfaces in order to increase the reliability of the results. Results.Experimental results show a quantitative analysis of measurements consisting Latency, CPU and Disk throughput while running a Cassandra cluster in Bare Metal and Container Environments.A statistical analysis summarizing the performance of Cassandra cluster is surveyed.

    Results.Experimental results show a quantitative analysis of measurements consisting Latency, CPU and Disk throughput while running a Cassandra cluster in Bare Metal and Container Environments.A statistical analysis summarizing the performance of Cassandra cluster is surveyed.

    Conclusions. With the detailed analysis, the resource utilization of the database was similar in both the bare-metal and container scenarios. Disk throughput is similar in the case of mixed load and containers have a slight overhead in the case of write loads for both the maximum load case and 66% of maximum load case. The latency values inside the container are slightly higher for all the cases. The mean value analysis and higher moment analysis helps us in doing a finer analysis of the results. The confidence intervals calculated show that there is a lot of variation in the disk performance which might be due to compactions happening randomly. Future work in the area can be done on compaction strategies.

  • 89.
    Kamisetty Jananni Narasimha, Shiva Sai Sri Harsha Vardhan
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Forecasting Trajectory Data: A study by Experimentation2017Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Context. The advances in location-acquisition and mobile computing techniques have generated massive spatial trajectory data. Such spatial trajectory data accumulated by telecommunication operators is huge, analyzing the data with a right tool or method can uncover patterns and connections which can be used for improving telecom services. Forecasting trajectory data or predicting next location of users is one of such analysis. It can be used for producing synthetic data and also to determine the network capacity needed for a cell tower in future.

    Objectives. The objectives of this thesis is, Firstly, to have a new application for CWT (Collapsed Weighted Tensor) method. Secondly, to modify the CWT method to predict the location of a user. Thirdly, to provide a suitable method for the given Telenor dataset to predict the user’s location over a period of time.

     

    Methods. The thesis work has been carried out by implementing the modified CWT method. The predicted location obtained by modified CWT cannot be determined to which time stamp it belongs as the given Telenor dataset contains missing time stamps. So, the modified CWT method is implemented in two different methods.

    1. Replacing missing values with first value in dataset.
    2. Replacing missing values with second value in dataset.

    These two methods are implemented and determined which method can predict the location of users with minimal error.

     

    Results. The results are carried by assuming that the given Telenor dataset for one week will be same as that for the next week. Users are selected in a random sample and above mentioned methods are performed. Furthermore, RMSD values and computational time are calculated for each method and selected users.

     

    Conclusion. Based on the analysis of the results, Firstly, it can be concluded that CWT method have been modified and used for predicting the user’s location for next time stamp. Secondly, the method can be extended to predict over a period of time. Finally, modified CWT method predicts location of the user with minimal error when missing values are replaced by first value in the dataset.

  • 90.
    Kankatala, Sriram
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Performance Analysis of kNN on large datasets using CUDA & Pthreads: Comparing between CPU & GPU2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Several organizations have large databases which are growing at a rapid rate day by day, which need to be regularly maintained. Content based searches are similar searched based on certain features that are obtained from various multi media data. For various applications like multimedia content retrieval, data mining, pattern recognition, etc., performing the nearest neighbor search is a challenging task in multidimensional data. The important factors in nearest neighbor search kNN are searching speed and accuracy. Implementation of kNN on GPU is an ongoing research from last few years, focusing on improving the performance of kNN. By considering these aspects, our research has been started and found a gap in this research area. This master thesis shows effective and efficient parallelism on multi-core of CPU and GPU to compare the performance with single core CPU. This paper shows an experimental implementation of kNN on single core CPU, Mutli-core CPU and GPU using C, Pthreads and CUDA respectively. We considered different levels of inputs (size, dimensions) to evaluate the performance. The experiment shows the GPU outperforms for kNN  when compared to CPU single core with a factor of approximately 5.8 to 16 and CPU multi-core with a factor of approximately 1.2 to 3 for different levels of inputs.

  • 91.
    Kanmantha Reddy, Pruthvi Raj Reddy
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Comparative Analysis of Virtual Desktops in Cloud: Performance comparison of OpenStack Private Cloud and AWS Public cloud2005Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
  • 92.
    Kari, Raywon Teja
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Smart Placement of Virtual Machines: Optimizing Energy Consumption2016Självständigt arbete på avancerad nivå (masterexamen), 80 poäng / 120 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Context: Recent trends show that there is a tremendous shift from IT companies following traditional methods by hosting their applications/systems in self-managed on premise data centers to using the so-called cloud data centers. Cloud computing has received immense popularity due to its architecture and the ease of usage. Due to this increase in demand and shift in practices, there has been a tremendous increase in number of data centers over a period, resulting in increase of energy consumption. In this thesis work, a research is carried out on optimizing the energy consumption of a typical cloud data center. OpenStack cloud computing software is chosen as the platform in this research. We have used live migration as a key aspect in this research.

    Objectives: In this research, our objectives are as follows:

    • Design an OpenStack testbed to implement the migration of virtual machines.
    • To estimate the energy consumption of the data center.
    • To design a heuristic algorithm to evaluate the performance metrics and to optimize the overall energy consumption.

    Methods: We have used PowerAPI, a software tool to estimate the energy consumption of hosts as well as virtual machines. A heuristic algorithm is designed and implemented in an instrumental OpenStack testbed to optimize the energy consumption. Server consolidation and load balancing of virtual machines methodologies are used in the heuristic algorithm design. Our research is carried out against the functionality of Nova scheduler of OpenStack.

    Results: Results section describes the values of performance metrics yielded by carrying out the experiment. The obtained results showed that energy can be optimized significantly by modifying the way OpenStack nova scheduler can work. The experiment is carried out on vanilla OpenStack and OpenStack with the heuristic algorithm in place, In the second case, the nova scheduler algorithms are not used but the heuristic algorithm is used instead. The CPU utilization and CPU load were noticed to be higher than the metrics observed in case of OpenStack with nova scheduler. Energy consumption is observed to be lesser than the consumption in OpenStack design with nova scheduler.

    Conclusions: The research tells that energy consumption can be optimized significantly using desired algorithms without compromising the service quality it offers. However, the design impacts on CPU slightly as the metrics are observed to be higher when compared to that in case of OpenStack with nova scheduler. Although it won’t have noticeable impact on the system.

  • 93. Kassahun, Solomon
    et al.
    Demessie, Atinkut
    Ilie, Dragos
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    A PMIPv6 Approach to Maintain Network Connectivity During VM Live Migration Over the Internet2014Ingår i: 2014 IEEE 3RD INTERNATIONAL CONFERENCE ON CLOUD NETWORKING (CLOUDNET), Luxembourg: IEEE , 2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    We present a live migration solution based on Proxy Mobile IPv6 (PMIPv6), a light-weight mobility protocol standardized by IETF. PMIPv6 handles node mobility without requiring any support from the moving nodes. In addition, PMIPv6 works with IPv4, IPv6 and dual-stack nodes. Our results from a real testbed show that network connectivity is successfully maintained with little signaling overhead and with short virtual machine (VM) downtime. As far as we know, this is the first time PMIPv6 is used to enable live migration beyond the scope of a LAN.

  • 94.
    Kaveti, Akash
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Effectiveness of Backup and Disaster Recovery in Cloud: A Comparative study on Disk and Cloud based Backup and Disaster Recovery2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Context: Definitive information is what makes enterprises in the contemporary world continuously move up the ladder in today’s world. Hence they need to be always up to date with the latest advancements. A key point in the enterprise structure is Backup and Disaster Recovery, DR system and this has very high scope for development since it can be integrated with a lot of our daily requirements. On account of this, it has a lot of applicability in future for development of technology. Due to this, we have chosen a Fast Moving Consumer Goods Company, FMCG to conduct experimentation on their Backup and DR system.

    Objectives: In every organization, Backup and DR plays a crucial role in Business Continuity Planning. This work relates to associate backup and recovery plan with an organizational view. And thereby work on its association with Recovery Time Objective, Recovery Point Objective, time taken for backup, time take for recovery and Total Cost of Ownership.

    Methods: Literature study is the first step to understand present scenario of trending technologies. Hence our understanding led us to conduct an experimental setup where we compared data that was collected in a case study and evaluated its performance of Backup and DR problems that are faced in today’s technology dominated world.

    Results: In our research, we took various parameters into consideration, which affect performance of an enterprise Backup and DR system. This drove us to assess disk-based and cloud-based Backup and DR plans in the FMCG environment.

    Conclusions: In conclusion, we summate that even though there have been a lot of theories and research on how Backup and DR is vital, we still lag behind in research work on which the organizations can rely upon to shift towards advanced technologies without risking their competence. With sufficient research on the entrepreneurial environment, we can improve performance enterprises and improve our present knowledge about cloud Backup and DR thereby improving its conventional usage in the present world.

  • 95.
    Khan, Fahim
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Mazarati, Pierre Celestin
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Khan, Nasir
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Effect of Primary Network on Performance of Spectrum Sharing System over Nakagami-m Fading Channel2013Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    During the last few years, we have witnessed that radio spectrum is becoming a valuable and scarce resource due to the increasing demand of multimedia services. However, recent research has shown that most of the available radio spectrum is not used effectively and is wasted. So, to utilize the radio spectrum effectively, a new technology has been introduced known as “Cognitive Radio”. In cognitive radio, a secondary user (SU) uses the vacant holes in licensed spectrum when it is not occupied by a primary user (PU) without causing interference to the PU transmission. Accessing vacant holes in the licensed user spectrum without causing interference to the PU is a complicated task. Therefore, alternative spectrum sharing techniques have gained popularity. Using these techniques, an SU can share the licensed spectrum with a PU at the same time without causing interference to the PU transmission. As a result, a secondary user should have an optimal power allocation policy in order to get a high transmission rate while still keeping the interference caused to the primary user below a threshold value. Under limited spectrum conditions, spectrum sharing relay networks have gained much popularity by providing reliability over direct transmission. In this thesis, we investigate an amplify-and-forward (AF) relay network performance in a spectrum sharing environment. Here, we consider the impact of the primary transmitter on the spectrum sharing system in the presence of a Nakagami-m fading channel, where the fading parameter m (m is an integer) can be used to deal with a variety of channel scenarios.

  • 96. Kim, Kyeong Jin
    et al.
    Duong, Trung Quang
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Elkashlan, Maged
    Yeoh, Phee Lep
    Poor, H. Vincent
    Lee, Moon Ho
    Spectrum Sharing Single-Carrier in the Presence of Multiple Licensed Receivers2013Ingår i: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248, Vol. 12, nr 10, s. 5223-5235Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, maximal-ratio combining (MRC) and selection combining (SC) are proposed in spectrum sharing single-carrier networks with multiple primary user receivers (PU-Rxs). Taking into account the peak interference power at the PU-Rx's and the maximum transmit power at the secondary user (SU), the impact of multiple PU-Rx's on the secondary network is characterized when the secondary user receiver (SURx) is equipped with multiple antennas. In doing so, exact and asymptotic expressions are derived for the cumulative distribution function, taking into account two realistic scenarios: 1) non-identical frequency selective fading between the secondary user transmitter (SU-Tx) and the PUs, and 2) frequency selective fading between the SU-Tx and the SU-Rx. Based on these, exact and asymptotic expressions for the outage probability and average bit error rate are derived. Furthermore, an exact closedform expression for the ergodic capacity is derived. It is shown that the asymptotic diversity gain depends only on the number of receive antennas and the number of multipath channels. It is further shown that the number of PU-Rx's and fading severities between the SU-Tx and the PU-Rx's have no impact on the asymptotic diversity gain.

  • 97.
    Kodide, Alekhya
    et al.
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för tillämpad signalbehandling.
    Chu, Thi My Chinh
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kreativa teknologier.
    Zepernick, Hans-Jürgen
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Outage probability of multiple relay networks over kappa-mu Shadowed fading2016Ingår i: 2016, 10th International Conference on Signal Processing and Communication Systems, ICSPCS 2016 - Proceedings, Institute of Electrical and Electronics Engineers (IEEE), 2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we study the outage probability of an opportunistic multiple relay communication system over κ-μ shadowed fading channels for both amplify-and-forward and decode-and-forward relaying protocols. We first provide an exact analysis of the impact of κ-μ shadowed fading on the outage probability of the system. To simplify the obtained analytical expression of the outage probability, we further approximate the κ-μ, shadowed fading channel by a Nakagami-m fading model. In order to illustrate the suitability of the approximation, numerical results are provided revealing that the exact outage probability using κ-μ, shadowed fading and the results obtained by approximating the fading by the Nakagami-m fading model match well as long as the parameters of the shadowed fading translate to integer values of the fading severity parameter m. Further, Monte-Carlo simulations have been conducted to validate the derived analytical expressions of the outage probability. Finally, the effect of network parameters such as the average transmit power at the source and the relay, the impact of the number of relays, the influence of the transmission distances and the fading parameters on the outage probability of the considered system is also illustrated through numerical examples. © 2016 IEEE.

  • 98.
    Kolli, Samuel Sushanth
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem. Blekinge Institute of Technology.
    Evaluating Energy Consumption of Distributed Storage Systems: Comparative analysis2016Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Context : Big Data and Cloud Computing nowadays require large amounts of storage that are accessible by many servers. The Energy consumed by these servers as well as that consumed by hosts providing the storage has been growing rapidly over the recent years. There are various approaches to save energy both at the hardware and software level, respectively. In the context of software, this challenge requires identification of new development methodologies that can help reduce the energy footprint of the Distributed Storage System. Until recently, reducing the energy footprint of Distributed Storage Systems is a challenge because there is no new methodology implemented to reduce the energy footprint of the Distributed Storage Systems. To tackle this challenge, we evaluate the energy consumption of Distributed Storage Systems by using a Power Application Programming Interface (PowerAPI) that monitors, in real-time, the energy consumed at the granularity of a system process.

    Objectives : In this study we investigate the Energy Consumption of distributed storage system. We also attempt to understand the effect on energy consumption for various patters of video streams. Also we have observed different measurement approaches for energy performance.

    Methods : The method is to use a power measuring software library while a synthetic load generator generates the load i.e., video data streams. The Tool which generates the workload is Standard Performance Evaluation Corporation Solution File Server (SPECsfs 2014) and PowerAPI is the software power monitoring library to evaluate the energy consumption of distributed storage systems of GlusterFS and Compuverde.

    Results : The mean and median values of power samples in mill watts for Compuverde higher than Gluster. For Compuverde the mean and median values until the load increment of three streams was around a 400 milliwatt value. The values of mean and median for the Gluster system were gradually increasing.

    Conclusions : The results show Compuverde having a higher consumption of energy than Gluster as it has a higher number of running processes that implement additional features that do not exist in Gluster. Also we have concluded that the conpuverde performed better for higher values of Load i.e., video data streams.

  • 99.
    Kolluri, Saiphani Krishna Priyanka Kolluri
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    APPLYING LEAN PRINCIPLES FOR PERFORMANCE ORIENTED SERVICE DESIGN OF VIRTUAL NETWORK FUNCTIONS FOR NFV INFRASTRUCTURE: Roles and Relationships2016Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Context. Network Function Virtualization was recently proposed by European Telecommunications Standards Institute (ETSI) to improve the network service flexibility by virtualization of network services and applications that run on hardware. To virtualize network functions, the software is decoupled from underlying physical hardware. NFV aims to transform industries by reducing capital investments on hardware by using commercial-of-the-shelf (COTS) hardware. NFV makes rapid innovative growth in telecom services through software based service deployment.

    Objectives. This thesis work aims to investigate how business organizations function and the roles in defining a service relationship model. The work also aims to define a service relationship model and to validate it via proof of concept using network function virtualization as a service. For this thesis, we finally apply lean principles for the defined service relationship model to reduce waste and investigate how lean benefits the model to be proven as performance service oriented.

    Methods. The essence of this work is to make a business organization lean by investigating its actions and applying lean principles. To elaborate, this thesis work involves in a research of papers from IEEE, TMF, IETF and Ericsson. It results in modelling of a PoC by following requirement analysis methodology and by applying lean principles to eliminate unnecessary processes which doesn’t add any value.

    Results. The results of the work include a full-fledged service relationship model that include three service levels with roles that can fit in to requirement specifications of NFV infrastructure. The results also show the service levels functionalities and their relationships between the roles. It has also been observed that the services that are needed to be standardized are defined with syntax for ways to describe network functions. It is observed that lean principles benefit the service relationship model from reducing waste factors and hereby providing a PoC which is performance service oriented.

    Conclusions. We conclude that roles defined are fit for the service relationship model designed. Moreover, we conclude that the model can hence contain the flow of service by standardizing the subservices and reducing waste interpreted with lean principles and there is a need for further use case proof of the model in full scale industry trials. It also concludes the ways to describe network functions syntax which follows lean principles that are essential to have them for the sub-services standardization. However, PoC defined can be an assurance to the NFV infrastructure.

  • 100.
    Komu, Miika
    et al.
    Ericsson Res, FIN.
    Morabito, Roberto
    Ericsson Res, FIN.
    Kauppinen, Tero
    Ericsson Res, FIN.
    Kjallman, Jimmy
    Ericsson Res, FIN.
    Yao, Yong
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Power Consumption in Remote Gaming: an Empirical Evaluation2016Ingår i: 2016 IEEE Conference on Computer Communications Workshops (INFOCOM WKSHPS), IEEE, 2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    The thin-client approach for gaming is becoming more popular. For instance, Nvidia Shield, Valve Steam and Shinra technologies have offerings based on the concept. In remote cloud gaming, the game is being executed and processed in the cloud while the user receives a video and audio stream of the game, in a very similar way as with remote desktop clients. At the same time, clouds are moving towards the end-users as "edge clouds" with different standardization bodies, such Open Mobile Edge Cloud and Open Fog Consortium, giving momentum for the efforts. Were remote gaming approaches to utilize edge clouds, the games could be played without installing any infrastructure at the homes of end-users while keeping network delays to the latency-sensitive games low. While waiting for such edge-cloud deployments to substantiate, even regional clouds could be utilized for the purpose. In such environments, remote cloud gaming can already now be utilized by game companies as an alternative to traditional download-and-install games in order to support, e.g., anti-piracy protection. While the incentives for the game companies are relatively clear, the end-user experience has been investigated mainly from the viewpoint of latency. In this paper, we fill a research gap related to energy efficiency by showing that mobile phone users can save between 12 and 32 % power by utilizing remote gaming instead of playing with a native app. Our prototype is based on GamingAnywhere open-source software for which we have also integrated a gamepad for easier controls. We show power measurements both with a 2D and 3D games, and also additional measurements with a smart TV-stick.

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