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  • 1.
    Ahmadi Mehri, Vida
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    An Investigation of CPU utilization relationship between host and guests in a Cloud infrastructure2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

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

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

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

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

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

  • 2.
    Ammar, Doreid
    et al.
    Norwegian Univ Sci & Technol, NOR.
    De Moor, Katrien
    Norwegian Univ Sci & Technol, NOR.
    Xie, Min
    Next Generat Serv, Telenor Res, NOR.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Heegaard, Poul
    Norwegian Univ Sci & Technol, NOR.
    Video QoE Killer and Performance Statistics in WebRTC-based Video Communication2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, we investigate session-related performance statistics of a Web-based Real-Time Communication (WebRTC) application called appear. in. We explore the characteristics of these statistics and explore how they may relate to users' Quality of Experience (QoE). More concretely, we have run a series of tests involving two parties and according to different test scenarios, and collected real-time session statistics by means of Google Chrome's WebRTC-internals tool. Despite the fact that the Chrome statistics have a number of limitations, our observations indicate that they are useful for QoE research when these limitations are known and carefully handled when performing post-processing analysis. The results from our initial tests show that a combination of performance indicators measured at the sender's and receiver's end may help to identify severe video freezes (being an important QoE killer) in the context of WebRTC-based video communication. In this paper the performance indicators used are significant drops in data rate, non-zero packet loss ratios, non-zero PLI values, and non-zero bucket delay.

  • 3.
    Ayyagari, Nitin Reddy
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Databases For Mediation Systems: Design and Data scaling approach2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Context: There is continuous growth in data generation due to wide usage of modern communication systems. Systems have to be designed which can handle the processing of these data volumes efficiently. Mediation systems are meant to serve this purpose. Databases form an integral part of the mediation systems. Suitability of the databases for such systems is the principle theme of this work.

    Objectives: The objective of this thesis is to identify the key requirements for databases that can be used as part of Mediation systems, gain a thorough understanding of various features, the data models commonly used in databases and to benchmark their performance.

    Methods: Previous work that has been carried out on various databases is studied as a part of literature review. Test bed is set up as a part of experiment and performance metrics such as throughput and total time taken were measured through a Java based client. Thorough analysis has been carried out by varying various parameters like data volumes, number of threads in the client etc.

    Results: Cassandra has a very good write performance for event and batch operations. Cassandra has a slightly better read performance when compared to MySQL Cluster but this differentiation withers out in case of fewer number of threads in the client.

    Conclusions: On evaluation of MySQL Cluster and Cassandra we conclude that they have several features that are suitable for mediation systems. On the other hand, Cassandra does not guarantee ACID transactions while MySQL Cluster has good support. There is need for further evaluation on new generation databases which are not mature enough as of now.

  • 4.
    Bjorklund, Svante
    et al.
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för matematik och naturvetenskap.
    Johansson, Tommy
    Swedish Def Res Agcy FOI, SE-58111 Linkoping, Sweden..
    Petersson, Henrik
    Swedish Def Res Agcy FOI, SE-58111 Linkoping, Sweden..
    Target Classification in Perimeter Protection with a Micro-Doppler Radar2016Inngår i: 2016 17TH INTERNATIONAL RADAR SYMPOSIUM (IRS), 2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In security surveillance at the perimeter of critical infrastructure, such as airports and power plants, approaching objects have to be detected and classified. Especially important is to distinguish between humans, animals and vehicles. In this paper, micro-Doppler data (from movement of internal parts of the target) have been collected with a small radar of a low complexity and cost-effective type. From time-velocity diagrams of the data, some physical features have been extracted and used in a support vector machine classifier to distinguish between the classes "human", "animal" and "man-made object". Both the type of radar and the classes are suitable for perimeter protection. The classification result are rather good, 77% correct classification. Particularly interesting is the surprisingly good ability to distinguish between humans and animals. This also indicates that we can choose to have limitations in the radar and still solve the classification task.

  • 5.
    Bjorklund, Svante
    et al.
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för matematik och naturvetenskap.
    Petersson, Henrik
    Swedish Def Res Agcy FOI, SE-58111 Linkoping, Sweden..
    Hendeby, Gustaf
    Swedish Def Res Agcy FOI, SE-58111 Linkoping, Sweden.;Linkoping Univ, SE-58183 Linkoping, Sweden..
    Features for micro-Doppler based activity classification2015Inngår i: IET radar, sonar & navigation, ISSN 1751-8784, E-ISSN 1751-8792, Vol. 9, nr 9, s. 1181-1187Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Safety and security applications benefit from better situational awareness. Radar micro-Doppler signatures from an observed target carry information about the target's activity, and have potential to improve situational awareness. This article describes, compares, and discusses two methods to classify human activity based on radar micro-Doppler data. The first method extracts physically interpretable features from the time-velocity domain such as the main cycle time and properties of the envelope of the micro-Doppler spectra and use these in the classification. The second method derives its features based on the components with the most energy in the cadence-velocity domain (obtained as the Fourier transform of the time-velocity domain). Measurements from a field trial show that the two methods have similar activity classification performance. It is suggested that target base velocity and main limb cadence frequency are indirect features of both methods, and that they do often alone suffice to discriminate between the studied activities. This is corroborated by experiments with a reduced feature set. This opens up for designing new more compact feature sets. Moreover, weaknesses of the methods and the impact of non-radial motion are discussed.

  • 6.
    Björklund, Svante
    et al.
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för matematik och naturvetenskap.
    Grahn, Per
    Nelander, Anders
    Pettersson, Mats
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för matematik och naturvetenskap.
    Measurement of Rank and Other Properties of Direct and Scattered Signals2016Inngår i: International Journal of Antennas and Propagation, ISSN 1687-5869, E-ISSN 1687-5877, Vol. 2016, artikkel-id 5483547Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have designed an experiment for low-cost indoor measurements of rank and other properties of direct and scattered signals with radar interference suppression in mind. The signal rank is important also in many other applications, for example, DOA (Direction of Arrival) estimation, estimation of the number of and location of transmitters in electronic warfare, and increasing the capacity in wireless communications. In real radar applications, such measurements can be very expensive, for example, involving airborne radars with array antennas. We have performed the measurements in an anechoic chamber with several transmitters, a receiving array antenna, and a moving reflector. Our experiment takes several aspects into account: transmitted signals with different correlation, decorrelation of the signals during the acquisition interval, covariance matrix estimation, noise eigenvalue spread, calibration, near-field compensation, scattering in a rough surface, and good control of the influencing factors. With our measurements we have observed rank, DOA spectrum, and eigenpatterns of direct and scattered signals. The agreement of our measured properties with theoretic and simulated results in the literature shows that our experiment is realistic and sound. The detailed description of our experiment could serve as help for conducting other well-controlled experiments. © Copyright 2016 Svante Björklund et al.

  • 7.
    Chadalapaka, Gayatri
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för datalogi och datorsystemteknik. BTH.
    Performance Assessment of Spectrum Sharing Systems: with Service Differentiation2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
  • 8. Chandu, Chiranjeevi
    Region of Interest Aware and Impairment Based Image Quality Assessment2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
  • 9.
    Chu, Thi My Chin
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kreativa teknologier.
    Zepernick, Hans-Jürgen
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kreativa teknologier.
    On Capacity of Full-Duplex Cognitive Cooperative Radio Networks with Optimal Power Allocation2017Inngår i: 2017 IEEE WIRELESS COMMUNICATIONS AND NETWORKING CONFERENCE (WCNC), IEEE , 2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, we examine a full-duplex transmission scheme for cognitive cooperative radio networks (CCRNs) to improve capacity. In this network, the secondary transmitter and secondary relay are allowed to utilize the licensed spectrum of the primary user by using underlay spectrum access. We assume that the CCRN is subject to the interference power constraint of the primary receiver and maximum transmit power limit of the secondary transmitter and secondary relay. Under these constraints, we propose an optimal power allocation policy for the secondary transmitter and the secondary relay based on average channel state information (CSI) to optimize capacity. Then, we derive an expression for the corresponding achievable capacity of the secondary network over Nakagami-m fading. Numerical results are provided for several scenarios to study the achievable capacity that can be offered by this full-duplex underlay CCRN using the proposed optimal power allocation scheme.

  • 10.
    Chu, Thi My Chinh
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Zepernick, Hans-Jürgen
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Phan, Hoc
    Univ Reading, GBR.
    Hybrid spectrum access with relay assisting both primary and secondary networks under imperfect spectrum sensing2016Inngår i: EURASIP Journal on Wireless Communications and Networking, ISSN 1687-1472, E-ISSN 1687-1499, artikkel-id 244Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper proposes a novel hybrid interweave-underlay spectrum access for a cognitive amplify-and-forward relay network where the relay forwards the signals of both the primary and secondary networks. In particular, the secondary network (SN) opportunistically operates in interweave spectrum access mode when the primary network (PN) is sensed to be inactive and switches to underlay spectrum access mode if the SN detects that the PN is active. A continuous-time Markov chain approach is utilized to model the state transitions of the system. This enables us to obtain the probability of each state in the Markov chain. Based on these probabilities and taking into account the impact of imperfect spectrum sensing of the SN, the probability of each operation mode of the hybrid scheme is obtained. To assess the performance of the PN and SN, we derive analytical expressions for the outage probability, outage capacity, and symbol error rate over Nakagami-m fading channels. Furthermore, we present comparisons between the performance of underlay cognitive cooperative radio networks (CCRNs) and the performance of the considered hybrid interweave-underlay CCRN in order to reveal the advantages of the proposed hybrid spectrum access scheme. Eventually, with the assistance of the secondary relay, performance improvements for the PN are illustrated by means of selected numerical results.

  • 11.
    Chu, Thi My Chinh
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Zepernick, Hans-Jürgen
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Phan, Hoc
    Duy Tan Univ, VNM.
    Optimal Secrecy Capacity of Underlay Cognitive Radio Networks with Multiple Relays2016Inngår i: MILCOM 2016 - 2016 IEEE MILITARY COMMUNICATIONS CONFERENCE, 2016, s. 162-167Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, we study the secrecy capacity of an underlay cooperative cognitive radio network (CCRN) where multiple relays are deployed to assist the secondary transmission. An optimal power allocation algorithm is proposed for the secondary transmitter and secondary relays to obtain the maximum secrecy capacity while satisfy the interference power constraint at the primary receiver and the transmit power budget of the CCRN. Since the optimization problem for the secrecy capacity is non-convex, we utilize an approximation and fitting method to convert the optimization problem into a geometric programming problem which then is solved by applying the Logarithmic barrier function. Numerical results are provided to study the effect of network parameters on the secrecy capacity. Through the numerical results, the advantage of the proposed power allocation algorithm compared to equal power allocation can also be observed.

  • 12.
    Ekramian, Elnaz
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för datalogi och datorsystemteknik.
    Automation of the test methods for packet loss and packet loss duration in the Ixia platform2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

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

  • 13.
    Fiedler, Markus
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för teknik och estetik.
    Chapala, Usha Kiran
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för teknik och estetik.
    Peteti, Sridhar
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för teknik och estetik.
    Modeling instantaneous quality of experience using machine learning of model trees2019Inngår i: 2019 11th International Conference on Quality of Multimedia Experience, QoMEX 2019, Institute of Electrical and Electronics Engineers Inc. , 2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    For service providers and operators, successful root cause analysis is essential for satisfactory service provisioning. However, reasons for sudden trend changes of the instantaneous Quality of Experience (QoE) may not always be immediately visible from underlying service- or network-level monitoring data. Thus, there is the challenge to pinpoint such moments of change in provisioning, and model the impact on instantaneous QoE, as a lead in root cause analysis. This work investigates the potential of Machine Learning (ML) of deriving time-interval-based models for instantaneous QoE ratings, obtained from a set of publicly available rating traces. In particular, the paper demonstrates the capability of the ML algorithm M5P to model trends of instantaneous QoE through model trees, consisting of piecewise linear functions over time. It is shown how and to which extent these functions can be used to estimate moments of change. Furthermore, the model trees support earlier assumptions about exponential shapes of instantaneous QoE over time as reactions to sudden changes of provisioning, such as video freezes. © 2019 IEEE.

  • 14.
    Fiedler, Markus
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för teknik och estetik.
    De Moor, Katrien
    Norwegian University of Science and Technology, NOR.
    Ravuri, Hemanth
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för teknik och estetik.
    Tanneedi, Prithvi
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för teknik och estetik.
    Chandiri, Mounika
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för teknik och estetik.
    Users On The Move: On Relationships Between QoE Ratings, Data Volumes and Intentions to Churn2017Inngår i: Proc. 2017 IEEE 42nd Conference on Local Computer Networks Workshops (LCN Workshops): Workshop On User MObility and VEhicular Networks (ON-MOVE), IEEE, 2017, s. 97-102Konferansepaper (Fagfellevurdert)
    Abstract [en]

    For a long time, the risk of customer churn, i.e. to leave an operator, has been used as argument in favor of Quality of Experience (QoE) research. However, the understanding of how churn behavior and QoE are related is still limited. This is problematic, as customer retention and churn prediction have grown in importance in face of ever-growing competition on the telecom market. The work presented in this paper aims to make a contribution in this respect, by exploring the relationships between QoE ratings, data volumes and churn risk through a longitudinal user study. Using an Experience Sampling Method-inspired approach we have been collecting weekly feedback on experienced quality, annoyance and intentions to churn from 22 users for up to eight weeks. Additionally, measurements of weekly used data volumes were collected. We observed churning behavior for 3 out of 22 participants and analyze the rating and data usage profiles of churners against non-churners. Furthermore, we investigate correlations of ratings and volumes, and find that “annoyed churners surf less”. Our findings point out warning signals for potential user churn as well as promising directions for future studies.

  • 15.
    Fiedler, Markus
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för teknik och estetik.
    Zepernick, Hans-Juergen
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för datavetenskap.
    Kelkkanen, Viktor
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för teknik och estetik.
    Network-induced temporal disturbances in virtual reality applications2019Inngår i: 2019 11th International Conference on Quality of Multimedia Experience, QoMEX 2019, Institute of Electrical and Electronics Engineers Inc. , 2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Virtual Reality (VR) applications put high demands on software and hardware in order to enable an immersive experience for the user and avoid causing simulator sickness. As soon as networks become part of the Motion-To-Photon (MTP) path between rendering and display, there is a risk for extraordinary delays that may impair Quality of Experience (QoE). This short paper provides an overview of latency measurements and models that are applicable to the MTP path, complemented by demands on user and network levels. It specifically reports on freeze duration measurements using a commercial TPCAST wireless VR solution, and identifies a corresponding stochastic model of the freeze length distribution, which may serve as disturbance model for VR QoE studies. © 2019 IEEE.

  • 16.
    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 Channels2015Inngår i: 2015 9TH INTERNATIONAL CONFERENCE ON SIGNAL PROCESSING AND COMMUNICATION SYSTEMS (ICSPCS), IEEE Communications Society, 2015Konferansepaper (Fagfellevurdert)
    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.

  • 17. 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 networks2014Inngår i: SECURITY AND COMMUNICATION NETWORKS, ISSN 1939-0114, Vol. 7, nr 12, s. 2542-2554Artikkel i tidsskrift (Fagfellevurdert)
    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

  • 18. Hellisten, Hans
    et al.
    Machado, Renato
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för matematik och naturvetenskap.
    Pettersson, Mats I.
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för matematik och naturvetenskap.
    Vu, Viet Thuy
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för matematik och naturvetenskap.
    Dammert, Patrik
    EXPERIMENTAL RESULTS ON CHANGE DETECTION BASED ON BAYES PROBABILITY THEOREM2015Inngår i: 2015 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS), IEEE Communications Society, 2015, s. 318-321Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper we propose a new change detection (CD) algorithm based on the Bayes theorem and probability assignments. Differently from any kind of likelihood ratio test (LRT) algorithms, the proposed algorithm does not present target alarms, but the probability of certain image position is a target position. In other words, the proposed method leads to quantitative estimates on the probability of a target at any pixel, whereas LRT algorithms can only be used as a figure of merit for any pixel to contain a target.

  • 19. 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 QoE2015Inngår i: 2015 7th International Workshop on Quality of Multimedia Experience, QoMEX 2015, IEEE Communications Society, 2015, Vol. Article number 7148093Konferansepaper (Fagfellevurdert)
    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.

  • 20.
    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 Cloud2016Inngår i: 2016 INTERNATIONAL CONFERENCE ON COMMUNICATIONS (COMM 2016), IEEE, 2016, s. 255-260Konferansepaper (Fagfellevurdert)
    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).

  • 21.
    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. scheme2017Inngår i: Multimedia tools and applications, ISSN 1380-7501, E-ISSN 1573-7721, Vol. 76, nr 15, s. 16463-16489Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 22.
    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 Optimization2016Inngår i: PROCEEDINGS OF THE 2016 INTERNATIONAL CONFERENCE ON ADVANCED TECHNOLOGIES FOR COMMUNICATIONS (ATC), IEEE, 2016, s. 210-214Konferansepaper (Fagfellevurdert)
    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.

  • 23.
    Johari Varnoosfaderani, Mohammad
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för tillämpad signalbehandling.
    Economical Debug Station For debugging 3G modem2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Communication world is growing with an incredible high speed. Every day comes new technologies and give us more access and opportunities in work and life.

    One of the most important branches is small cells and similar product families.

    It extends from a simple telegraph codes to 3G W-CDMA and 4G LTE networks.

    It offers mobile network operators a cost-effective alternative to macro-only deployments for meeting growing coverage and capacity demands.

    Making products and bring it to market is one part of the job. It is important that product be fault free and reliable. Due to this comes our need for test and debugging.

    Test and debugging have high value in massive production.

    This research is subjected to a small cell modem, this modem has different parts like:

    - Download link and upload link through fiber optic cables for CPRI.

    - Network part which include Wi-Fi and LAN.

    - GPS module.

    - eUSB for customization of modem firmware.

    - Com, I2C and JTAG ports for debugging or reprograming the modem.

    We need to develop a debug station to make debugging easier on this modem and having clear compare results. It is important to have a CPRI tester and GPS signal simulator in our debug station.

    Beside all of these we need to make free standalone debug station which save us money and time, and from other side it should be as accurate as possible which make it reliable.

    One of important tests which should get done on test object is Boundary scan in debug station.

    Debuggers mentioned that it is hard to stop the test process in each level and from other side it is hard to find the faults with pass/fail results.

    In this project we try to implement all necessary tests in one and same debug station.

    Debuggers use separate stations for function test and boundary scan test and eUSB programing, with help of this debug station we have all of these 3 main tests in same station and debugger can work independently to repair the boards without interfering in production process or waiting to get time to use function test station or boundary scan tester .

    One of the Results is saving time from debugger’s side and this is more effective for company to save money and give faster and better repair service.

    We should use calibrated and the most accurate tools for testing to get best result. 

  • 24.
    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 Channels2015Inngår i: 2015 9TH INTERNATIONAL CONFERENCE ON SIGNAL PROCESSING AND COMMUNICATION SYSTEMS (ICSPCS), IEEE Communications Society, 2015Konferansepaper (Fagfellevurdert)
    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.

  • 25.
    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 channels2015Inngår i: 2015 21st Asia-Pacific Conference on Communications, APCC 2015, IEEE Press, 2015, s. 427-432, artikkel-id Article number 7412551Konferansepaper (Fagfellevurdert)
    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.

  • 26.
    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 Constraint2016Inngår i: PROCEEDINGS OF THE 2016 INTERNATIONAL CONFERENCE ON ADVANCED TECHNOLOGIES FOR COMMUNICATIONS (ATC), IEEE, 2016, s. 38-42Konferansepaper (Fagfellevurdert)
    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.

  • 27.
    Kelkkanen, Viktor
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för teknik och estetik.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för teknik och estetik.
    A Test-bed for Studies of Temporal Data Delivery Issues in a TPCAST Wireless Virtual Reality Set-up2018Inngår i: 2018 28TH INTERNATIONAL TELECOMMUNICATION NETWORKS AND APPLICATIONS CONFERENCE (ITNAC), IEEE , 2018, s. 404-406Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Virtual Reality (VR) is becoming increasingly popular, and wireless cable replacements unleash the user of VR Head Mounted Displays (HMD) from the rendering desktop computer. However, the price to pay for additional freedom of movement is a higher sensitivity of the wireless solution to temporal disturbances of both video frame and input traffic delivery, as compared to its wired counterpart. This paper reports on the development of a test-bed to be used for studying temporal delivery issues of both video frames and input traffic in a wireless VR environment, here using TPCAST with a HTC Vive headset. We provide a solution for monitoring and recording of traces of (1) video frame freezes as observed on the wireless VR headset, and (2) input traffic from the headset and hand controls to the rendering computer. So far, the test-bed illustrates the resilience of the underlying WirelesslID technology and TCP connections that carry the input traffic, and will be used in future studies of Quality of Experience (QoE) in wireless desktop VR.

  • 28.
    Kelkkanen, Viktor
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för teknik och estetik.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för teknik och estetik.
    Coefficient of Throughput Variation as Indication of Playback Freezes in Streamed Omnidirectional Videos2018Inngår i: 2018 28TH INTERNATIONAL TELECOMMUNICATION NETWORKS AND APPLICATIONS CONFERENCE (ITNAC), IEEE , 2018, s. 392-397Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A large portion of today's network traffic consists of streamed video of large variety, such as films, television shows, live-streamed games and recently omnidirectional videos. A common way of delivering video is by using Dynamic Adaptive Streaming over HTTP (DASH), or recently with encrypted HTTPS. Encrypted video streams disable the use of Quality of Service (QoS) systems that rely on knowledge of application-dependent data, such as video resolution and bit-rate. This could make it difficult for a party providing bandwidth to efficiently allocate resources and estimate customer satisfaction. An application-independent way of measuring video stream quality could be of interest for such a party. In this paper, we investigate encrypted streaming of omni-directional video via YouTube to a smartphone in a Google Cardboard VR-headset. We monitored such sessions, delivered via both WiFi and mobile networks, at different times of day, implying different levels of congestion, and characterised the network traffic by using the Coefficient of Throughput Variation (CoTV) as statistic. We observe that this statistic shows to be able to indicate whether a stream is stable or unstable, in terms of potential video playback freezes, when the DASH delivery strategy is used.

  • 29. 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 Receivers2013Inngår i: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248, Vol. 12, nr 10, s. 5223-5235Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 30.
    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 fading2016Inngår i: 2016, 10th International Conference on Signal Processing and Communication Systems, ICSPCS 2016 - Proceedings, Institute of Electrical and Electronics Engineers (IEEE), 2016Konferansepaper (Fagfellevurdert)
    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.

  • 31.
    Kuruganti, NSR Sankaran
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Distributed databases for Multi Mediation: Scalability, Availability & Performance2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Context: Multi Mediation is a process of collecting data from network(s) & network elements, pre-processing this data and distributing it to various systems like Big Data analysis, Billing Systems, Network Monitoring Systems, and Service Assurance etc. With the growing demand for networks and emergence of new services, data collected from networks is growing. There is need for efficiently organizing this data and this can be done using databases. Although RDBMS offers Scale-up solutions to handle voluminous data and concurrent requests, this approach is expensive. So, alternatives like distributed databases are an attractive solution. Suitable distributed database for Multi Mediation, needs to be investigated.

    Objectives: In this research we analyze two distributed databases in terms of performance, scalability and availability. The inter-relations between performance, scalability and availability of distributed databases are also analyzed. The distributed databases that are analyzed are MySQL Cluster 7.4.4 and Apache Cassandra 2.0.13. Performance, scalability and availability are quantified, measurements are made in the context of Multi Mediation system.

    Methods: The methods to carry out this research are both qualitative and quantitative. Qualitative study is made for the selection of databases for evaluation. A benchmarking harness application is designed to quantitatively evaluate the performance of distributed database in the context of Multi Mediation. Several experiments are designed and performed using the benchmarking harness on the database cluster.

    Results: Results collected include average response time & average throughput of the distributed databases in various scenarios. The average throughput & average INSERT response time results favor Apache Cassandra low availability configuration. MySQL Cluster average SELECT response time is better than Apache Cassandra for greater number of client threads, in high availability and low availability configurations.Conclusions: Although Apache Cassandra outperforms MySQL Cluster, the support for transaction and ACID compliance are not to be forgotten for the selection of database. Apart from the contextual benchmarks, organizational choices, development costs, resource utilizations etc. are more influential parameters for selection of database within an organization. There is still a need for further evaluation of distributed databases.

  • 32.
    Kuzminykh, Ievgeniia
    et al.
    Kharkiv National University, UKR.
    Snihurov, Arkadii
    Kharkiv National University, UKR.
    Carlsson, Anders
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för datalogi och datorsystemteknik.
    Testing of communication range in ZigBee technology2017Inngår i: 14th International Conference The Experience of Designing and Application of CAD Systems in Microelectronics (CADSM), Institute of Electrical and Electronics Engineers (IEEE), 2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Abstract:In the rapidly growing Internet of Things (loT) applications from personal electronics to industrial machines and sensors are getting wirelessly connected to the Internet. Many well-known communication technologies such as WiFi, ZigBee, Bluetooth and cellular are used for transfer data in IoT. The choice of corresponding technology or combination of technologies depends on application or other factors such as data requirements, communication range, security and power demands, battery life. In this paper we will focus on ZigBee wireless technology and testing ZigBee end devices in order to see how transmission range impacts on quality parameters.

  • 33.
    Lagerspetz, E.
    et al.
    University of Helsinki, FIN.
    Flores, H.
    University of Helsinki, FIN.
    Mäkitalo, N.
    University of Helsinki, FIN.
    Hui, P.
    University of Helsinki, FIN.
    Nurmi, P.
    Lancaster University, GBR.
    Tarkoma, S.
    University of Helsinki, FIN.
    Passarella, A.
    IIT-CNR, ITA.
    Ott, J.
    Technical University of Munich, DEU.
    Reichl, P.
    University of Vienna, AUT.
    Conti, M.
    IIT-CNR, ITA.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för teknik och estetik.
    Singh, J.
    University of Cambridge, GBR.
    Strufe, T.
    Technische Universität Dresden, DEU.
    Hossfeld, T.
    University of Duisburg-Essen, DEU.
    Lindgren, A.
    RISE SICS, SWE.
    Quercia, D.
    Bell Labs Cambridge, GBR.
    Pervasive Communities in the Internet of People2018Inngår i: 2018 IEEE International Conference on Pervasive Computing and Communications Workshops, PerCom Workshops 2018, Institute of Electrical and Electronics Engineers Inc. , 2018, s. 40-45, artikkel-id 8480273Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The Internet has traditionally been a device-oriented architecture where devices with IP addresses are first-class citizens, able to serve and consume content or services, and their owners take part in the interaction only through those devices. The Internet of People (IoP) is a recent paradigm where devices become proxies of their users, and can act on their behalf. To realize IoP, new policies and rules for how devices can take actions are required. The role of context information grows as devices act autonomously based on the environment and existing social relationships between their owners. In addition, the social profiles of device owners determine e.g. how altruistic or resourceconserving they are in collaborative computing scenarios. In this paper we focus on community formation in IoP, a prerequisite for enabling collaborative scenarios, and discuss main challenges and propose potential solutions. © 2018 IEEE.

  • 34.
    Larsson, Andreas
    et al.
    Luleå Technical University.
    Ericson, Åsa
    Larsson, Tobias
    Luleå Technical University.
    Randall, Dave
    Engineering 2.0 - Exploring Lightweight Technologies for the Virtual Enterprise2008Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In a Virtual Enterprise setting, it becomes increasingly important to make sure that knowledge and expertise created in one discipline, domain or company is correctly understood and quickly utilized by other actors throughout the value chain. This paper discusses why lightweight technology seems like a particularly promising concept in this context, and why Virtual Enterprises could benefit from learning more about tag clouds, mashups, wikis, and other ‘lightweight' technologies, as complements to the large-scale, arguably ‘heavyweight', product life-cycle management (PLM) systems of current practice. The paper draws on data from a number of product development projects - ranging from the development of manufacturing tools and industrial drive systems, to aircraft engines and armored terrain vehicles. The paper identifies both the kinds of problem typically experienced in the Virtual Enterprise, in relation to knowledge sharing, and explores ways in which lightweight technology might be adapted to solve them.

  • 35.
    Louis, Sibomana
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Hans-Jürgen, Zepernick
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Ergodic Capacity of Multiuser Scheduling in Cognitive Radio Networks: Analysis and ComparisonArtikkel i tidsskrift (Fagfellevurdert)
  • 36.
    Louis, Sibomana
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Hans-Jürgen, Zepernick
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Performance Analysis of Opportunistic Scheduling with HARQ for Cognitive Radio Networks2015Inngår i: IEEE Wireless Communications and Networking Conference, New Orleans, USA: IEEE Computer Society, 2015, s. 411-416-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper analyzes the secondary network performance under the joint constraint of the primary user (PU) peak interference power and maximum transmit power limit of the secondary user (SU). In particular, N SU transmitters (SU-Txs) communicate with an SU receiver in the presence of a primary network with a PU transmitter and multiple PU receivers. Moreover, we exploit opportunistic scheduling where the SU-Tx with the best channel condition is scheduled for transmission. Analytical expressions of the outage probability and symbol error probability of the SU are obtained considering either perfect or statistical knowledge of the PU channel gains. Furthermore, we analyze the SU throughput for delay constrained applications with two hybrid automatic repeat request protocols, namely, repetition time diversity and incremental redundancy. Numerical results are provided to assess the effect of the number of SU-Txs and number of packet retransmissions on the secondary network performance. In addition, the impact of the primary network parameters on the secondary network is investigated.

  • 37.
    Louis, Sibomana
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Hans-Jürgen, Zepernick
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Hung, Tran
    On the Outage Capacity of an Underlay Cognitive Radio Network2015Inngår i: 2015 9TH INTERNATIONAL CONFERENCE ON SIGNAL PROCESSING AND COMMUNICATION SYSTEMS (ICSPCS), IEEE Press, 2015, s. 1-7-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, we consider a point-to-multipoint underlay cognitive radio network under the joint constraint of the primary user peak interference power and maximum transmit power limit of the secondary user (SU). Analytical expressions for the secondary outage capacity are obtained based on exact as well as approximate expressions of the first and second moments of the channel capacity. Numerical results are provided to assess the effect of the number of SU receivers and a given SU outage probability. We also evaluate the impact of the primary network parameters on the secondary network performance.

  • 38.
    Louis, Sibomana
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Hans-Jürgen, Zepernick
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Hung, Tran
    Mälardalens högskola, SWE.
    Charles, Kabiri
    University of Rwanda, RWA.
    A Framework for Packet Delay Analysis of Point-to-Multipoint Underlay Cognitive Radio Networks2017Inngår i: IEEE Transactions on Mobile Computing, ISSN 1536-1233, E-ISSN 1558-0660, Vol. 16, nr 9, s. 2408-2421Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents a queueing analytical framework for the performance evaluation of the secondary user (SU) packet transmission with service differentiation in a point-to-multipoint underlay cognitive radio network. The transmit power of the SU transmitter is subject to the joint outage constraint imposed by the primary user receivers (PU-Rxs) and the SU maximum transmit power limit. The analysis considers a queueing model for secondary traffic with multiple classes, and different types of arrival and service processes under a non-preemptive priority service discipline. The SU quality of service (QoS) is characterized by a packet timeout threshold and target bit error rate. Given these settings, analytical expressions of the packet timeout probability and average transmission time are derived for opportunistic and multicast scheduling. Moreover, expressions of the average packet waiting time in the queue and the total time in the system for each class of traffic are obtained. Numerical examples are provided to illustrate the secondary network performance with respect to various parameters such as number of PU-Rxs and SU receivers, SU packet arrival process, QoS requirements, and the impact of interference from the primary network to the secondary network.

  • 39.
    Machado, Renato
    et al.
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för matematik och naturvetenskap.
    Pettersson, Mats I.
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för matematik och naturvetenskap.
    Vu, Viet Thuy
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för matematik och naturvetenskap.
    Dammert, Patrik
    Hellsten, Hans
    EMPIRICAL-STATISTICAL ANALYSIS OF AMPLITUDE SAR IMAGES FOR CHANGE DETECTION ALGORITHMS2015Inngår i: 2015 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS), 2015, s. 365-368Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents an analysis of pre-filtered clutter VHF SAR images. The image data are reorganized into sub-vectors based on the observation of the image-pair magnitude samples. Based on this approach, we present a statistical description of the SAR clutter obtained by the subtraction between two real SAR images. The statistical analysis based on bivariate distribution data organized into different intervals of magnitude can be an important tool to further understand the properties of the backscattered signal, which can be a valuable premise for change detection processing.

  • 40.
    Minhas, Tahir Nawaz
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Shahid, Muhammad
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för tillämpad signalbehandling.
    Lövström, Benny
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för tillämpad signalbehandling.
    Rossholm, Andreas
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för tillämpad signalbehandling.
    Zepernick, Hans-Jürgen
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    QoE rating performance evaluation of ITU-T recommended video quality metrics in the context of video freezes2016Inngår i: Australian Journal of Electrical and Electronics Engineering, ISSN 1448-837X, Vol. 13, nr 2, s. 122-131Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In real-time video streaming, video quality can be degraded due to network performance issues. Among other artefacts, video freezing and video jumping are factors that influence user experience. Service providers, operators and manufacturers are interested in evaluating the quality of experience (QoE) objectively because subjective assessment of QoE is expensive and, in many user cases, subjective assessment is not possible to perform. Different algorithms have been proposed and implemented in this regard. Some of them are in the recommendation list of the ITU Telecommunication Standardization Sector (ITU-T). In this paper, we study the effect of the freezing artefact on user experience and compare the mean opinion score of these videos with the results of two algorithms, the perceptual evaluation of video quality (PEVQ) and temporal quality metric (TQM). Both metrics are part of the ITU-T Recommendation J.247 Annex B and C. PEVQ is a full-reference video quality metric, whereas TQM is a no-reference quality metric. Another contribution of this paper is the study of the impact of different resolutions and frame rates on user experience and how accurately PEVQ and TQM measure varying frame rates.

  • 41.
    Moshirian, Sanaz
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Performance of International roaming Location Update in 3G and 4G networks2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Since Mobile network operator (MNO) relies on many Business Support Systems (BSS) and Operation Support Systems (OSS) it should be assured that operator’s systems supports the requirements of the future.This thesis shall focus on the “start-to-end” aspects that must be considered to ensure that International Roaming continues to operate flawless. The thesis experience Long Term Evolution (LTE) in case of international roaming by measuring the end to end location update delay.In order to evaluate the LTE performance of international roaming, the delay time has been measured by the means of tracing tools for several different international roamers and the results has been compared with the results achieved for local user. The outcome has been compared with the respecting results in 3G network the statistical results has been provided and the graphs has been plotted to study the performance.Based on the results obtain on this thesis, it has been concluded that local user acts more stable to get attach to the network, i.e. there are less fluctuation in delay times for local user. Also the delay time in 3G networks is more than the LTE networks, however 3G networks acts more stable and there are less fluctuation to get connects to 3G networks.

  • 42.
    Nawaz, Omer
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för teknik och estetik.
    Minhas, Tahir Nawaz
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för teknik och estetik.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för teknik och estetik.
    QoE based comparison of H.264/AVC and WebM/VP8 in an error-prone wireless network2017Inngår i: Proceedings of the IM 2017 - 2017 IFIP/IEEE International Symposium on Integrated Network and Service Management / [ed] Chemouil P.,Simoes P.,Madeira E.,Secci S.,Monteiro E.,Gaspary L.P.,dos Santos C.R.P.,Charalambides M., Institute of Electrical and Electronics Engineers (IEEE), 2017, s. 1005-1010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Quality of Experience (QoE) management is a prime topic of research community nowadays as video streaming, online gaming and security applications are completely reliant on the network service quality. Moreover, there are no standard models to map Quality of Service (QoS) into QoE. HTTP media streaming is primarily used for such applications due to its coherence with the Internet and simplified management. The most common video codecs used for video streaming are H.264/AVC and Google's VP8. In this paper, we have analyzed the performance of these two codecs from the perspective of QoE. The most common end-user medium for accessing video content is via home based wireless networks. We have emulated an error-prone wireless network with different scenarios involving packet loss, packet delay and delay variation. The focus of this paper is evaluating the end user satisfaction with the multimedia content by subjective assessment using Mean Opinion Score (MOS). We have observed the overall superiority of H.264/AVC but the VP8 codec strongly gains ground in highly error-prone networks in terms of user satisfaction. © 2017 IFIP.

  • 43. Ngo, Hien Quoc
    et al.
    Matthaiou, Michail
    Duong, Trung Q.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Larsson, Erik G.
    Uplink Performance Analysis of Multicell MU-SIMO Systems With ZF Receivers2013Inngår i: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 62, nr 9, s. 4471-4483Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We consider the uplink of a multicell multiuser single-input multiple-output system (MU-SIMO), where the channel experiences both small- and large-scale fading. The data detection is done by using the linear zero-forcing technique, assuming the base station (BS) has perfect channel state information of all users in its cell. We derive new exact analytical expressions for the uplink rate, the symbol error rate (SER), and the outage probability per user, as well as a lower bound on the achievable rate. This bound is very tight and becomes exact in the large-number-of-antenna limit. We further study the asymptotic system performance in the regimes of high signal-to-noise ratio (SNR), large number of antennas, and large number of users per cell. We show that, at high SNRs, the system is interference limited, and hence, we cannot improve the system performance by increasing the transmit power of each user. Instead, by increasing the number of BS antennas, the effects of interference and noise can be reduced, thereby improving system performance. We demonstrate that, with very large antenna arrays at the BS, the transmit power of each user can be made inversely proportional to the number of BS antennas while maintaining a desired quality of service. Numerical results are presented to verify our analysis.

  • 44.
    Osekowska, Ewa
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för datalogi och datorsystemteknik.
    Johnson, Henric
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för datalogi och datorsystemteknik.
    Carlsson, Bengt
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för datalogi och datorsystemteknik.
    Grid size optimization for potential field based maritime anomaly detection2014Inngår i: 17TH MEETING OF THE EURO WORKING GROUP ON TRANSPORTATION, EWGT2014 / [ed] Benitez, FG Rossi, R, ELSEVIER SCIENCE BV , 2014, s. 720-729Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This study focuses on improving the potential field based maritime data modeling method, developed to extract traffic patterns and detect anomalies, in a clear, understandable and informative way. The method's novelty lies in employing the concept of a potential field for AIS vessel tracking data abstraction and maritime traffic representation. Unlike the traditional maritime surveillance equipment, such as radar or GPS, the AIS system comprehensively represents the identity and properties of a vessel, as well as its behavior, thus preserving the effects of navigational decisions, based on the skills of experienced seamen. In the developed data modeling process, every vessel generates potential charges, which value represent the vessel's behavior, and drops the charges at locations it passes. Each AIS report is used to assign a potential charge at the reported vessel positions. The method derives three construction elements, which define, firstly, how charges are accumulated, secondly, how a charge decays over time, and thirdly, in what way the potential is distributed around the source charge. The collection of potential fields represents a model of normal behavior, and vessels not conforming to it are marked as anomalous. In the anomaly detection prototype system STRAND, the sensitivity of anomaly detection can be modified by setting a geographical coordinate grid precision to more dense or coarse. The objective of this study is to identify the optimal grid size for two different conditions an open sea and a port area case. A noticeable shift can be observed between the results for the open sea and the port area. The plotted detection rates converge towards an optimal ratio for smaller grid sizes in the port area (60-200 meters), than in the open sea case (300-1000 meters). The effective outcome of the potential filed based anomaly detection is filtering out all vessels behaving normally and presenting a set of anomalies, for a subsequent incident analysis using STRAND as an information visualization tool.

  • 45.
    Popescu, Alexandru
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Yao, Yong
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Popescu, Adrian
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    A Management Architecture for Multimedia Communication in Cognitive Radio Networks2015Inngår i: Multimedia over Cognitive Radio Networks: Algorithms, Protocols, and Experiments / [ed] Hu, F; Kumar, S, CRC Press, 2015, s. 3-31Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 46.
    Shirmohamadi, Bamshad
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Bridging between Quality of Experience and Quality of Service through TCP Flag Ratios2016Inngår i: Proceedings - Conference on Local Computer Networks, LCN, IEEE Computer Society , 2016, Vol. Part F126504, s. 192-198, artikkel-id 7856156Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Since the early days of Quality of Experience (QoE) research, relationships to Quality of Service (QoS) and corresponding QoE-QoS models have been of great interest to the research community. However, the manifold quality transformations throughout the communication stack, together with accessibility issues of QoS parameters inside networks, hamper availability, applicability and generality of such models. On this background, the paper proposes the use of specific transport layer information, in particular the ratios of selected flags used by the TCP protocol, as QoE indicators. In our work, we show that such flag ratios help identifying, characterizing and quantifying user annoyance from observations anywhere along the TCP connection. As use case, we address video streaming from a TCP CUBIC web server in a wireless setting. © 2016 IEEE.

  • 47.
    Sibomana, Louis
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Performance Analysis of Cognitive Radio Networks under Spectrum Sharing and Security Constraints2016Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The cognitive radio network (CRN) concept has been proposed as a solution to the growing demand and underutilization of the radio spectrum. To improve the radio spectrum utilization, CRN technology allows the coexistence of licensed and unlicensed systems over the same spectrum. In an underlay spectrum sharing system, secondary users (SUs) transmit simultaneously with the primary users (PUs) in the same frequency band given that the interference caused by the SU to the PU remains below a tolerable interference limit. Besides the transmission power limitation, a secondary network is subject to distinct channel impairments such as fading and interference from the primary transmissions. Also, CRNs face new security threats and challenges due to their unique cognitive characteristics.This thesis analyzes the performance of underlay CRNs and underlay cognitive relay networks under spectrum sharing constraints and security constraints. Distinct SU transmit power policies are obtained considering various interference constraints such as PU outage constraint or PU peak interference power constraint.

    The thesis is divided into an introduction and two research parts based on peer-reviewed publications. The introduction provides an overview of radio spectrum management, basic concepts of CRNs, and physical layer security. In the first research part, we study the performance of underlay CRNs with emphasis on a multiuser environment.In Part I-A, we consider a secondary network with delay-tolerant applications and analyze the ergodic capacity. Part I-B analyzes the secondary outage capacity which characterises the maximum data rate that can be achieved over a channel for a given outage probability. In Part I-C, we consider a secondary network with delay constrained applications, and derive expressions of the outage probability and delay-limited throughput. Part I-D presents a queueing model that provides an analytical tool to evaluate the secondary packet-level performance with multiple classes of traffic considering general interarrival and service time distributions. Analytical expressions of the SU average packet transmission time, waiting time in the queue, andtime spent in the system are provided.In the second research part, we analyze the physical layer security for underlay CRNs and underlay cognitive relay networks. Analytical expressions of the probability of non-zero secrecy capacity and secrecy outage probability are derived.Part II-A considers a single hop underlay CRN in the presence of multiple eavesdroppers (EAVs) and multiple SU-Rxs. In Part II-B, an underlay cognitive relay network in the presence of multiple secondary relays and multiple EAVs is studied.Numerical examples illustrate that it is possible to exploit the physical layer characteristics to achieve both security and quality of service in CRNs while satisfying spectrum sharing constraints.

  • 48.
    Sibomana, Louis
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Tran, Hung
    Tran, Quang Anh
    Impact of secondary user communication on security communication of primary user2015Inngår i: Security and Communication Networks, ISSN 1939-0114, E-ISSN 1939-0122, Vol. 8, nr 18, s. 4177-4190Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cognitive radio network concept has been considered as a promising solution to improve the spectrum utilization. However, it may be vulnerable to security problems as the primary user (PU) and secondary user (SU) access the same resource. In this paper, we consider a system model where an eavesdropper (EAV) illegally listens to the PU communication in the presence of a SU transmitter (SU-Tx) communicating with a SU receiver (SU-Rx). The SU-Tx transmit power is subject to the peak transmit power constraint of the SU and outage probability constraint of the PU. Given this context, the effect of the interference from the SU-Tx to the EAV on the primary system security is investigated. In particular, analytical expressions of the probability of existence of non-zero secrecy capacity and secrecy outage probability of the PU are derived. Moreover, the performance analysis of the secondary network is examined where closed-form expressions of the symbol error probability and achievable rate are presented. Numerical examples are provided to evaluate the impact of the primary system parameters and channel conditions among users on the system performance of secondary and primary networks. Interestingly, our results reveal a fact that the security of the primary network strongly depends on the channel condition of the SU-Tx to the EAV link and the transmit power policy of the SU-Tx. Copyright (C) 2015 John Wiley & Sons, Ltd.

  • 49.
    Sibomana, Louis
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Tran, Hung
    Zepernick, Hans-Jürgen
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    On Physical Layer Security for Cognitive Radio Networks with Primary User Interference2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, we investigate the secondary network physical layer security under the outage constraint of the primary user (PU) receiver and interference from the PU transmitter to the secondary network. In particular, a secondary user (SU) transmitter sends confidential messages to trusted multiple SU receivers (SU-Rxs) in the presence of multiple eavesdroppers (EAVs). Further, we exploit multiuser diversity where the SU-Rx with best channel condition is scheduled for transmission. Then, analytical expressions of the probability of existence of non-zero secrecy capacity and secrecy outage probability are obtained. Analytical and simulation results are provided to evaluate the effect of the number of SU-Rxs and number of EAVs on the secondary system. Interestingly, the numerical results show that the interference from the primary network to the secondary network is an important parameter to improve the secondary network security.

  • 50.
    Siddiqui, Rafid
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    On Fundamental Elements of Visual Navigation Systems2014Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Visual navigation is a ubiquitous yet complex task which is performed by many species for the purpose of survival. Although visual navigation is actively being studied within the robotics community, the determination of elemental constituents of a robust visual navigation system remains a challenge. Motion estimation is mistakenly considered as the sole ingredient to make a robust autonomous visual navigation system and therefore efforts are made to improve the accuracy of motion estimations. On the contrary, there are other factors which are as important as motion and whose absence could result in inability to perform seamless visual navigation such as the one exhibited by humans. Therefore, it is needed that a general model for a visual navigation system be devised which would describe it in terms of a set of elemental units. In this regard, a set of visual navigation elements (i.e. spatial memory, motion memory, scene geometry, context and scene semantics) are suggested as building blocks of a visual navigation system in this thesis. A set of methods are proposed which investigate the existence and role of visual navigation elements in a visual navigation system. A quantitative research methodology in the form of a series of systematic experiments is conducted on these methods. The thesis formulates, implements and analyzes the proposed methods in the context of visual navigation elements which are arranged into three major groupings; a) Spatial memory b) Motion Memory c) Manhattan, context and scene semantics. The investigations are carried out on multiple image datasets obtained by robot mounted cameras (2D/3D) moving in different environments. Spatial memory is investigated by evaluation of proposed place recognition methods. The recognized places and inter-place associations are then used to represent a visited set of places in the form of a topological map. Such a representation of places and their spatial associations models the concept of spatial memory. It resembles the humans’ ability of place representation and mapping for large environments (e.g. cities). Motion memory in a visual navigation system is analyzed by a thorough investigation of various motion estimation methods. This leads to proposals of direct motion estimation methods which compute accurate motion estimates by basing the estimation process on dominant surfaces. In everyday world, planar surfaces, especially the ground planes, are ubiquitous. Therefore, motion models are built upon this constraint. Manhattan structure provides geometrical cues which are helpful in solving navigation problems. There are some unique geometric primitives (e.g. planes) which make up an indoor environment. Therefore, a plane detection method is proposed as a result of investigations performed on scene structure. The method uses supervised learning to successfully classify the segmented clusters in 3D point-cloud datasets. In addition to geometry, the context of a scene also plays an important role in robustness of a visual navigation system. The context in which navigation is being performed imposes a set of constraints on objects and sections of the scene. The enforcement of such constraints enables the observer to robustly segment the scene and to classify various objects in the scene. A contextually aware scene segmentation method is proposed which classifies the image of a scene into a set of geometric classes. The geometric classes are sufficient for most of the navigation tasks. However, in order to facilitate the cognitive visual decision making process, the scene ought to be semantically segmented. The semantic of indoor scenes as well as semantic of the outdoor scenes are dealt with separately and separate methods are proposed for visual mapping of environments belonging to each type. An indoor scene consists of a corridor structure which is modeled as a cubic space in order to build a map of the environment. A “flash-n-extend” strategy is proposed which is responsible for controlling the map update frequency. The semantics of the outdoor scenes is also investigated and a scene classification method is proposed. The method employs a Markov Random Field (MRF) based classification framework which generates a set of semantic maps.

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