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  • 51.
    Alay, Özgü
    et al.
    Simula Research Laboratory, Norway.
    Lutu, Andra
    Simula Research Laboratory, Norway.
    Peón-Quirós, Miguel
    IMDEA Networks Institute, Spain.
    Mancuso, Vincenzo
    IMDEA Networks Institute, Spain.
    Hirsch, Thomas
    Celerway Communications, Norway.
    Evensen, Kristian
    Celerway Communications, Norway.
    Hansen, Audun
    Celerway Communications, Norway.
    Alfredsson, Stefan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Karlsson, Jonas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Safari Khatouni, Ali
    Politecnico di Torino, Italy.
    Mellia, Marco
    Politecnico di Torino, Italy.
    Ajmone Marsan, Marco
    IMDEA Networks Institute, Spain and Politecnico di Torino, Italy.
    Experience: An open platform for experimentation with commercial mobile broadband networks2017In: MobiCom '17 Proceedings of the 23rd Annual International Conference on Mobile Computing and Networking, New York: ACM Digital Library, 2017, p. 70-78Conference paper (Refereed)
    Abstract [en]

    Open experimentation with operational Mobile Broadband (MBB) networks in the wild is currently a fundamental requirement of the research community in its endeavor to address the need of innovative solutions for mobile communications. Even more, there is a strong need for objective data about stability and performance of MBB (e.g., 3G/4G) networks, and for tools that rigorously and scientifically assess their status. In this paper, we introduce the MONROE measurement platform: an open access and flexible hardware-based platform for measurements and custom experimentation on operational MBB networks. The MONROE platform enables accurate, realistic and meaningful assessment of the performance and reliability of 11 MBB networks in Europe. We report on our experience designing, implementing and testing the solution we propose for the platform. We detail the challenges we overcame while building and testing the MONROE testbed and argue our design and implementation choices accordingly. We describe and exemplify the capabilities of the platform and the wide variety of experiments that external users already perform using the system

  • 52.
    Alayon Glazunov, Andres
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    A survey of the application of the spherical vector wave mode expansion approach to antenna-channel interaction modeling2014In: Radio Science, ISSN 0048-6604, E-ISSN 1944-799X, Vol. 49, no 8, p. 663-679Article in journal (Refereed)
    Abstract [en]

    This paper provides an overview of recent advances in the modeling, analysis, and measurements of interactions between antennas and the propagation channel in multiple antenna systems based on the spherical vector wave mode expansion of the electromagnetic field and the antenna scattering matrix. It demonstrates the importance and usefulness of this approach to gain further insights into a variety of topics such as physics-based propagation channel modeling, mean effective gain, channel correlation, propagation channel measurements, antenna measurements and testing, the number of degrees of freedom of the radio propagation channel, channel throughput, and diversity systems. The paper puts particular emphasis on the unified approach to antenna-channel analysis at the same time as the antenna and the channel influence are separated. Finally, the paper provides the first bibliography on the application of the spherical vector wave mode expansion of the electromagnetic field to antenna-channel interactions.

  • 53.
    Alayon Glazunov, Andres
    Ericsson research.
    Considerations regarding the number of RAKE fingers required in CDMA RAKE receivers1998Conference paper (Other academic)
  • 54.
    Alayon Glazunov, Andres
    Telia Research.
    Performance analysis of impulse radio based on ultra wideband channelmodel for indoor communications2002Conference paper (Refereed)
  • 55.
    Alayon Glazunov, Andres
    et al.
    Ericsson Research.
    Hamberg, Lennart
    Ericsson research.
    Medbo, Jonas
    Building shielding loss measurementsand modeling at the 5GHz band in office building areas2000Conference paper (Refereed)
  • 56.
    Alayon Glazunov, Andres
    et al.
    Telia Research.
    Karlsson, Peter
    Telia Research.
    Ljung, Rickard
    Telia research.
    Cost analysis of smart antenna systems deployment2005In: Proc. VTC 2005-Spring Vehicular Technology Conf. 2005 IEEE 61st, 2005, Vol. 1, p. 329-333Conference paper (Refereed)
    Abstract [en]

    3G networks and services are being launched all over the world The basic investments on equipment have already been done according to preliminary traffic forecasts. However, if the mobile data traffic acquires "internet- like" proportions, network capacity shortage will become a reality in densely populated areas, such as city centers and business parks. In that case smart antennas may be the solution. Based on this assumption the financial aspects of the deployment of smart antenna systems in the 3G UMTS networks have been evaluated. We have evaluated the potential CAPEX and OPEX savings provided by such a system compared to more conventional antenna systems. Despite their indicative nature, our calculations show that cost savings of the order of 10% to 25% are feasible if the cost increase of the smart antenna equipment is of the order of 100% to 50% of the conventional antennas equipment costs, respectively.

  • 57.
    Albarrán Munoz, Isaac
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Parras Ruiz De Azúa, Manuel
    Telecommunication Services’ Migration to the Cloud: Network Performance analysis2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

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

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

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

  • 58.
    Alci, Kenan
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    TFTP loading of programs into a Microcontroller’s flash memory and evaluation of Microchip’s TCP/IP stack with ENC28J602014Report (Other academic)
    Abstract [en]

    This project began with a microprocessor platform developed by two master’s students: Albert López and Francisco Javier Sánchez. Their platform was designed as a gateway for sensing devices operating in the 868 MHz band. The platform consists of a Texas Instruments MSP430F5437A microcontroller and a Microchip ENC28J60 Ethernet cont roller connected to the MSP430 processor by a Serial Peripheral Interface.

    Javier Lara Peinado implemented prototype white space sensors using the platform developed by the earlier two students. As part of his effort, he partially implemented a Trivial File Transfer Protocol (TFTP) system for loading programs in to the flash memory of the microcontroller using Microchip’s TCP/IP stack.  However, he was not successful in loading programs into the flash as the TFTP transfer got stuck at the first block.

    The first purpose of this project was to find and fix the error(s) in the TFTP loading of programs into the MSP430’s flash memory. The second purpose of this project was to evaluate Microchip’s TCP/IP stack in depth.  This report describes measurements of UDP transmission rates. Additionally, the TFTP processing rate is measured and the TFTP program loading code is documented.  The report concludes with suggestions for possible improvements of this system.

  • 59.
    Alexander, Karlsson
    Mälardalen University, School of Innovation, Design and Engineering.
    Design and Development of a Wireless Multipoint E-stop System for Autonomous Haulers2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Safety-related functions are important in autonomous industrial applications and are featured in an extensive body of work contained within the standards. The implementation of safety-related systems is commonly done by an external company at a great cost and with limited flexibility. Thus, the objective of this thesis was to develop and implement a safety-related system using o-the-shelf products and to analyse how well it can comply with the established standards of safety-related functions. This work has sought to review the current standards for safety-functions, the eectsof harsh radio environments on safety-related systems, and how to validate the safety-function.The system development process was used to gain knowledge by rst building the concept based on pre-study. After the pre-study was nished, the process moved to the development of software, designed to maintain a wireless heartbeat as well as to prevent collisions between the autonomous and manual-driven vehicles at a quarry, and implementation of the system in real hardware. Finally, a set of software (simulations) and hardware (measurements in an open-pit mine) tests were performed to test the functionality of the system. The wireless tests showed that the system adhered to the functional requirements set by the company, however, the evaluated performance level according to ISO 13849-1 resulted in performance level B which is insucient for a safety-related function. This work demonstrates that it is not possible to develop a safety-related system using the off-the-shelf products chosen, without hardware redundancy.

  • 60.
    Alexiou, Nikolaos
    et al.
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Basagiannis, S.
    Petridou, S.
    Formal security analysis of near field communication using model checking2016In: Computers & security (Print), ISSN 0167-4048, E-ISSN 1872-6208, Vol. 60, p. 1-14Article in journal (Refereed)
    Abstract [en]

    Near field communication (NFC) is a short-range wireless communication technology envisioned to support a large gamut of smart-device applications, such as payment and ticketing. Although two NFC devices need to be in close proximity to communicate (up to 10 cm), adversaries can use a fast and transparent communication channel to relay data and, thus, force an NFC link between two distant victims. Since relay attacks can bypass the NFC requirement for short-range communication cheaply and easily, it is important to evaluate the security of NFC applications. In this work, we present a general framework that exploits formal analysis and especially model checking as a means of verifying the resiliency of NFC protocol against relay attacks. Toward this goal, we built a continuous-time Markov chain (CTMC) model using the PRISM model checker. Firstly, we took into account NFC protocol parameters and, then, we enhanced our model with networking parameters, which include both mobile environment and security-aware characteristics. Combining NFC specifications with an adversary's characteristics, we produced the relay attack model, which is used for extracting our security analysis results. Through these results, we can explain how a relay attack could be prevented and discuss potential countermeasures.

  • 61.
    Alexiou, Nikolaos
    et al.
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Basagiannis, S.
    Petridou, S.
    Security analysis of NFC relay attacks using probabilistic model checking2014In: IWCMC 2014 - 10th International Wireless Communications and Mobile Computing Conference, IEEE , 2014, p. 524-529Conference paper (Refereed)
    Abstract [en]

    Near Field Communication (NFC) is a short-ranged wireless communication technology envisioned to support a large gamut of smart-device applications, such as payment and ticketing applications. Two NFC-enabled devices need to be in close proximity, typically less than 10 cm apart, in order to communicate. However, adversaries can use a secret and fast communication channel to relay data between two distant victim NFC-enabled devices and thus, force NFC link between them. Relay attacks may have tremendous consequences for security as they can bypass the NFC requirement for short range communications and even worse, they are cheap and easy to launch. Therefore, it is important to evaluate security of NFC applications and countermeasures to support the emergence of this new technology. In this work we present a probabilistic model checking approach to verify resiliency of NFC protocol against relay attacks based on protocol, channel and application specific parameters that affect the successfulness of the attack. We perform our formal analysis within the probabilistic model checking environment PRISM to support automated security analysis of NFC applications. Finally, we demonstrate how the attack can be thwarted and we discuss the successfulness of potential countermeasures.

  • 62.
    Alexiou, Nikolaos
    et al.
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Gisdakis, Stylianos
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Laganà, Marcello
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Papadimitratos, Panagiotis
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Towards a secure and privacy-preserving multi-service vehicular architecture2013In: 2013 IEEE 14th International Symposium on a World of Wireless, Mobile and Multimedia Networks, WoWMoM 2013, IEEE , 2013, p. 6583472-Conference paper (Refereed)
    Abstract [en]

    Intensive efforts in industry, academia and standardization bodies have brought vehicular communications (VC) one step before commercial deployment. In fact, future vehicles will become significant mobile platforms, extending the digital life of individuals with an ecosystem of applications and services. To secure these services and to protect the privacy of individuals, it is necessary to revisit and extend the vehicular Public Key Infrastructure (PKI)-based approach towards a multi-service security architecture. This is exactly what this work does, providing a design and a proof-of-concept implementation. Our approach, inspired by long-standing standards, is instantiated for a specific service, the provision of short-term credentials (pseudonyms). Moreover, we elaborate on its operation across multiple VC system domains, and craft a roadmap for further developments and extensions that leverage Web-based approaches. Our current results already indicate our architecture is efficient and can scale, and thus can meet the needs of the foreseen broad gamut of applications and services, including the transportation and safety ones.

  • 63.
    Alexiou, Nikolaos
    et al.
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Laganá, Marcello
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Gisdakis, Stylianos
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Khodaei, Mohammad
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Papadimitratos, Panagiotis
    KTH, School of Electrical Engineering (EES), Communication Networks.
    VeSPA: Vehicular security and privacy-preserving architecture2013In: HotWiSec 2013: Proceedings of the 2013 ACM Workshop on Hot Topics on Wireless Network Security and Privacy, 2013, p. 19-23Conference paper (Refereed)
    Abstract [en]

    Vehicular Communications (VC) are reaching a near deploment phase and will play an important role in improving road safety, driving efficiency and comfort. The industry and the academia have reached a consensus for the need of a Public Key Infrastructure (PKI), in order to achieve security, identity management, vehicle authentication, as well as preserve vehicle privacy. Moreover, a gamut of proprietary and safety applications, such as location-based services and pay-as-you-drive systems, are going to be offered to the vehicles. The emerging applications are posing new challenges for the existing Vehicular Public Key Infrastructure (VPKI) architectures to support Authentication, Authorization and Accountability (AAA), without exposing vehicle privacy. In this work we present an implementation of a VPKI that is compatible with the VC standards. We propose the use of tickets as cryptographic tokens to provide AAA and also preserve vehicle privacy against adversaries and the VPKI. Finally, we present the efficiency results of our implementation to prove its applicability.

  • 64.
    Alfredsson, Stefan
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Del Giudice, Giacomo
    Politecnico di Bari, Italy.
    Garcia, Johan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Brunstrom, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    De Cicco, Luca
    Ecole superieure d'Electricite, France; Politecnico di Bari, Italy.
    Mascolo, Saverio
    Politecnico di Bari, Italy.
    Impact of TCP Congestion Control on Bufferbloat in Cellular Networks2013In: Proceedings of the 14th IEEE International Symposium on a World of Wireless, Mobile and Multimedia Networks (WoWMoM 2013) / [ed] Angelos Lazaris, Balaji Rengarajan, IEEE Press, 2013Conference paper (Refereed)
    Abstract [en]

    The existence of excessively large and too filled network buffers, known as bufferbloat, has recently gained attention as a major performance problem for delay-sensitive applications. One important network scenario where bufferbloat may occur is cellular networks.

    This paper investigates the interaction between TCP congestion control and buffering in cellular networks. Extensive measurements have been performed in commercial 3G, 3.5G and 4G cellular networks, with a mix of long and short TCP flows using the CUBIC, NewReno and Westwood+ congestion control algorithms. The results show that the completion times of short flows increase significantly when concurrent long flow traffic is introduced. This is caused by increased buffer occupancy from the long flows. In addition, for 3G and 3.5G the completion times are shown to depend significantly on the congestion control algorithms used for the background flows, with CUBIC leading to significantly larger completion times.

  • 65.
    Alfredsson, Stefan
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Del Giudice, Giacomo
    Politecnico di Bari, Italy.
    Garcia, Johan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Brunstrom, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    De Cicco, Luca
    Ecole superieure d'Electricite, France; Politecnico di Bari, Italy.
    Mascolo, Saverio
    Politecnico di Bari, Italy.
    Observations of Bufferbloat in Swedish Cellular Networks2013In: Proceedings of the 9th Swedish National Computer Networking Workshop (SNCNW 2013) / [ed] Bengt Ahlgren, 2013Conference paper (Refereed)
  • 66. Alhammouri, M.
    et al.
    Muftic, Sead
    KTH, School of Information and Communication Technology (ICT), Computer and Systems Sciences, DSV.
    A design of an access control model for multilevel-security documents2008Conference paper (Refereed)
    Abstract [en]

    In this paper we describe an access control model for multilevel-security documents, those structured into multiple sections based on certain security classifications. Our access control system uses XACML policies to allow documents, whose contents have varying sensitivity levels, to be created, viewed, and edited by groups that have members with varying clearance levels, while enforcing the required security constraints.

  • 67.
    Ali, Rahman
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    Design of Building Blocks in Digital Baseband Transceivers for Body-Coupled Communication2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

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

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

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

  • 68.
    Ali Tandra, Sabrina
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Rizvi, S.M. Sarwarul Islam
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Security for Cloud Based Services2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

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

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

  • 69.
    Ali, Waqas Liaqat
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Securing Safebook: Secure Data Access Control and Key Management for Safebook2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

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

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

  • 70. Alinia, Bahram
    et al.
    Yousefi, Hamed
    Talebi Mazraeh Shahi, Mohammad Sadegh
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Khonsari, Ahmad
    Maximizing Quality of Aggregation in Delay-Constrained Wireless Sensor Networks2013In: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 17, no 11, p. 2084-2087Article in journal (Refereed)
    Abstract [en]

    In this letter, both the number of participating nodes and spatial dispersion are incorporated to establish a bi-objective optimization problem for maximizing the quality of aggregation under interference and delay constraints in tree-based wireless sensor networks (WSNs). The formulated problem is proved to be NP-hard with respect to Weighted-sum scalarization and a distributed heuristic aggregation scheduling algorithm, named SDMAX, is proposed. Simulation results show that SDMAX not only gives a close approximation of the Pareto-optimal solution, but also outperforms the best, to our knowledge, existing alternative proposed so far in the literature.

  • 71.
    Alisauskas, Saulius
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Community based testing2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

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

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

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

  • 72.
    Allgayer, Rodrigo
    et al.
    Electrical Engineering Department, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.
    Muller, Ivan
    Electrical Engineering Department, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.
    Pereira, Carlos
    Electrical Engineering Department, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.
    Cavalcante, Andre
    Electronic and Telcomunication Department, Federal University of Amazonas (UFAM), Manaus, Brazil.
    Pignaton de Freitas, Edison
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES). Institute of Informatics, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.
    Larsson, Tony
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Analysis of distributed control system using remote method invocation in wireless network2011In: IECON 2011 Proceedings: 37th Annual Conference of the IEEE Industrial Electronics Society, New York: IEEE, 2011, p. 346-351, article id 6119277Conference paper (Refereed)
    Abstract [en]

    This work presents the temporal analysis for a distributed differential control system for a mobile robot deployed on a wireless network using the SunSPOT platform. The system is programmed in Java and each of its part is executed in a distinct processor which cooperates via a wireless network. The communication between the network nodes is made by remote procedure calls, which are implemented by a minimum version of the Java RMI (mRMI), presented in this work. Simulation results are compared to experimental data acquired by the deployment of the system on real devices, the SunSPOTs. The comparisons reveal that the distributed solution presents fairly good results besides the inserted errors due to the wireless communication. © 2011 IEEE.

  • 73.
    Allison, R.S.
    et al.
    York University, Canada.
    Brunnstrom, Kjell
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Chandler, D.M.
    Shizuoka University, Japan.
    Colett, H.
    Intel Corp, US.
    Corriveau, P.
    Intel Corp, US.
    Daly, S.
    Dolby Laboratories Inc, US.
    Goel, J.
    Qualcomm Technologies, Inc, US.
    Long, J.Y.
    Intel Corp, US.
    Wilcox, L.M.
    York University, Canada.
    Yaacob, Y.
    Shizuoka University, Japan.
    Yang, S. N.
    Pacific University, US.
    Zhang, Y.
    Xi’an Jiaotong University, China.
    Perspectives on the definition of visually lossless quality for mobile and large format displays2018In: Journal of Electronic Imaging, Vol. 27, no 5, article id 053035Article in journal (Refereed)
    Abstract [en]

    Advances in imaging and display engineering have given rise to new and improved image and videoapplications that aim to maximize visual quality under given resource constraints (e.g., power, bandwidth).Because the human visual system is an imperfect sensor, the images/videos can be represented in a mathematicallylossy fashion but with enough fidelity that the losses are visually imperceptible—commonly termed“visually lossless.” Although a great deal of research has focused on gaining a better understanding ofthe limits of human vision when viewing natural images/video, a universally or even largely accepted definitionof visually lossless remains elusive. Differences in testing methodologies, research objectives, and targetapplications have led to multiple ad-hoc definitions that are often difficult to compare to or otherwise employ inother settings. We present a compendium of technical experiments relating to both vision science and visualquality testing that together explore the research and business perspectives of visually lossless image quality,as well as review recent scientific advances. Together, the studies presented in this paper suggest that a singledefinition of visually lossless quality might not be appropriate; rather, a better goal would be to establish varyinglevels of visually lossless quality that can be quantified in terms of the testing paradigm.

  • 74.
    Allison, R.S.
    et al.
    York University, Centre for Vision Research, Toronto, Canada.
    Brunnström, Kjell
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information and Communication systems. RISE AB (Acreo).
    Chandler, D.M.
    Shizuoka University, Hamamatsu, Shizuoka, Japan.
    Colett, H.
    Intel Corp., Santa Clara, California, United States.
    Corriveau, P.
    Intel Corp., Santa Clara, California, United States.
    Daly, S.
    Dolby Laboratories Inc., Sunnyvale, California, United States.
    Goel, J.
    Qualcomm Technologies, Inc., Display Video Processing Group, Markham, Canada.
    Long, J.Y.
    Intel Corp., Santa Clara, California, United States.
    Wilcox, L.M.
    York University, Centre for Vision Research, Toronto, Canada.
    Yaacob, Y.
    Shizuoka University, Hamamatsu, Shizuoka, Japan.
    Yang, S. N.
    Pacific University, Forest Grove, Oregon, United States.
    Zhang, Y.
    Xi’an Jiaotong University, School of Electronic and Information Engineering, Xi’an, China.
    Perspectives on the definition of visually lossless quality for mobile and large format displays2018In: Journal of Electronic Imaging, Vol. 27, no 5, p. 1-23, article id 053035Article in journal (Refereed)
    Abstract [en]

    Advances in imaging and display engineering have given rise to new and improved image and videoapplications that aim to maximize visual quality under given resource constraints (e.g., power, bandwidth).Because the human visual system is an imperfect sensor, the images/videos can be represented in a mathematicallylossy fashion but with enough fidelity that the losses are visually imperceptible—commonly termed“visually lossless.” Although a great deal of research has focused on gaining a better understanding ofthe limits of human vision when viewing natural images/video, a universally or even largely accepted definitionof visually lossless remains elusive. Differences in testing methodologies, research objectives, and targetapplications have led to multiple ad-hoc definitions that are often difficult to compare to or otherwise employ inother settings. We present a compendium of technical experiments relating to both vision science and visualquality testing that together explore the research and business perspectives of visually lossless image quality,as well as review recent scientific advances. Together, the studies presented in this paper suggest that a singledefinition of visually lossless quality might not be appropriate; rather, a better goal would be to establish varyinglevels of visually lossless quality that can be quantified in terms of the testing paradigm.

  • 75.
    Almas, Muhammad Shoaib
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    PERFORMANCE EVALUATION OF PROTECTION FUNCTIONS FOr IEC 61850-9-2 PROCESS BUS USING REAL-TIME HARDWARE-IN-THE-loop simulation approach2013Conference paper (Refereed)
    Abstract [en]

    With the evolution of Process Bus (IEC 61850-9-2), there is a need to assess the performance of protection schemes using process bus against those where traditional copper wires are implemented. Differential protection is the fundamental and most commonly used protection for transformers, motors and generators. In this paper a power system is modelled in SimPowerSystems and is executed in real-time using Opal-RT’s eMEGAsim real-time simulator. Hardware-in-the loop validation of a process bus implementation for differential protection for a two winding transformer is done by using the differential protection feature in ABB’s RED-670 relay. The event reports generated by the ABB relay during Hardware-in-the-Loop testing are compared for three different scenarios i.e. complete process bus, hybrid process bus and complete traditional topology.   

  • 76.
    Almkvist, Magnus
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Wahren, Marcus
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Preserving Integrity inTelecommunication Networks Opened bythe Parlay Service Interface2002Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

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

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

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

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

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

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

  • 77.
    Almquist, Mathias
    et al.
    Linköping University, Department of Computer and Information Science.
    Almquist, Viktor
    Linköping University, Department of Computer and Information Science.
    Analysis of 360° Video Viewing Behaviours2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this thesis we study users' viewing motions when watching 360° videos in order to provide information that can be used to optimize future view-dependent streaming protocols. More specifically, we develop an application that plays a sequence of 360° videos on an Oculus Rift Head Mounted Display and records the orientation and rotation velocity of the headset during playback. The application is used during an extensive user study in order to collect more than 21 hours of viewing data which is then analysed to expose viewing patterns, useful for optimizing 360° streaming protocols. 

  • 78.
    Almquist, Mathias
    et al.
    Linköping University, Department of Computer and Information Science. Linköping University, Faculty of Science & Engineering.
    Almquist, Viktor
    Linköping University, Department of Computer and Information Science. Linköping University, Faculty of Science & Engineering.
    Vergara Alonso, Ekhiotz Jon
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Communication Energy Overhead of Mobiles Games2015In: MobiGames '15: Proceedings of the 2nd Workshop on Mobile Gaming, Association for Computing Machinery (ACM), 2015, p. 1-6Conference paper (Other academic)
    Abstract [en]

    Although a significant proportion of the mobile apps are games there has been little attention paid to their specific characteristics with respect to communication energy. In this paper we select 20 mobile games among the top 100 free Android games, and study their data patterns and communication energy use over a total of 25 hours of playing. The analysis of the energy for communication over 3G networks indicates that there is a wide variation among the games, the largest footprint being 8 times higher than the lowest one. The results also indicates both app-specific and category-specific relations between data pattern and energy use, as well as variations in CPU utilisation.

  • 79.
    Almudhari, Haider
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    Effektivisering av materialhantering gällande plåtrullar i SSAB:s Stålhamn: En fallstudie på Oxelösunds Hamn AB2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Today, manufacturing companies are under competitive and rapid changes in the global market. It challenges companies working with material manufacturing and distribution networks at a global level to continually improve their business. The actors operating within a single supply chain should unite to increase their ability to compete and remain flexible, as a response to the effects of globalization. By creating business goals, sharing information, risks, and profits, all operators in the chain can benefit.

    This case study has been carried out in one of Oxelösund Harbor's operations, namely SSAB's Steel Port, which they operate for SSAB in Oxelösund municipality. The steel harbor has an important role in SSAB's supply chain because it acts as SSAB's port of shipment where materials coming from SSAB in Borlänge and Oxelösund are stored until they are shipped to other ports in the world. Today, Oxelösund Harbor is experiencing inefficient information and material flow within the Steel Harbor's operations.

    The purpose of the study is to investigate material handling in terms of which transport and storage methods are carried out in one of the steel ports operations, the coil terminal. Thereafter, the study will clarify what kind of waste there is and find improvements to streamline information and material flow when handling coils in the coil terminal.

    The study was primarily conducted through observations, unstructured and to a lesser extent structured interviews, structured email conversations and data collection. The focus was on finding the possible areas that could become more efficient in practice and then finding the theory and literature that highlight the shortcomings found. Some theories that will be emphasized, because of their relevance, are Lean, inventory and supply chain theory.

    The study's results and analysis show that the challenges that hinder the efficiency of the coil terminal are based on internal and external factors. Internal factors consist of unnecessary movement of materials, reworking in office and unused work shifts. External factors are caused by vendors in the form of information insufficiency and material input/output.

    The results of the study conclude that the optimal solution is that the cooperation between the operators in the chain is improved so that flow of information becomes better and reduce uncertainty in delivery and shipping. Furthermore, the study encourages Oxelösund Harbor to collect data, in the form of statistics, concerning daily events in Stålhamnen, highlighting problems and costs that are hidden and start utilizing the unused work shift during the night, as well as reducing the stock.

  • 80.
    Alodeh, Maha
    et al.
    Univ Luxembourg, Luxembourg.
    Spano, Danilo
    Univ Luxembourg, Luxembourg.
    Kalantari, Ashkan
    Linköping University, Department of Electrical Engineering, Communication Systems. Linköping University, Faculty of Science & Engineering. Univ Luxembourg, Luxembourg.
    Tsinos, Christos G.
    Univ Luxembourg, Luxembourg.
    Christopoulos, Dimitrios
    Newtec Satcom, Belgium.
    Chatzinotas, Symeon
    Univ Luxembourg, Luxembourg.
    Ottersten, Bjorn
    Univ Luxembourg, Luxembourg.
    Symbol-Level and Multicast Precoding for Multiuser Multiantenna Downlink: A State-of-the-Art, Classification, and Challenges2018In: IEEE Communications Surveys and Tutorials, ISSN 1553-877X, E-ISSN 1553-877X, Vol. 20, no 3, p. 1733-1757Article in journal (Refereed)
    Abstract [en]

    Precoding has been conventionally considered as an effective means of mitigating or exploiting the interference in the multiantenna downlink channel, where multiple users are simultaneously served with independent information over the same channel resources. The early works in this area were focused on transmitting an individual information stream to each user by constructing weighted linear combinations of symbol blocks (codewords). However, more recent works have moved beyond this traditional view by: 1) transmitting distinct data streams to groups of users and 2) applying precoding on a symbol-persymbol basis. In this context, the current survey presents a unified view and classification of precoding techniques with respect to two main axes: 1) the switching rate of the precoding weights, leading to the classes of block-level and symbol-level precoding and 2) the number of users that each stream is addressed to, hence unicast, multicast, and broadcast precoding. Furthermore, the classified techniques are compared through representative numerical results to demonstrate their relative performance and uncover fundamental insights. Finally, a list of open theoretical problems and practical challenges are presented to inspire further research in this area.(1)

  • 81. Alonso, Juan M.
    et al.
    Nordhamn, Amanda
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Olofsson, Simon
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Voigt, Thiemo
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Bounds on the lifetime of wireless sensor networks with lossy links and directional antennas2016In: Wireless Network Performance Enhancement via Directional Antennas: Models, Protocols, and Systems, Boca Raton, FL: CRC Press, 2016, p. 329-361Chapter in book (Refereed)
  • 82. Alowayed, Y.
    et al.
    Canini, M.
    Marcos, P.
    Chiesa, Marco
    KTH.
    Barcellos, M.
    Picking a partner: A fair blockchain based scoring protocol for autonomous systems2018In: ANRW 2018 - Proceedings of the 2018 Applied Networking Research Workshop, Association for Computing Machinery (ACM), 2018, p. 33-39Conference paper (Refereed)
    Abstract [en]

    We tackle the problem of enabling Autonomous Systems to evaluate network providers on the basis of their adherence to Service Level Agreements (SLAs) regarding interconnection agreements. In current Internet practices, choices of interconnection partners are driven by factors such as word of mouth, personal relationships, brand recognition and market intelligence, and not by proofs of previous performance. Given that Internet eXchange Points provide increasingly more peering choices, rudimentary schemes for picking interconnection partners are not adequate anymore. Although the current interconnection ecosystem is shrouded in confidentiality, our key observation is that recently-emerged blockchain technology and advances in cryptography enable a privacy-preserving decentralized solution based on actual performance measurements. We propose the concept of SLA score to evaluate network providers and introduce a privacy-preserving protocol that allows networks to compute and verify SLA scores.

  • 83.
    Al-Rawi, Mohammed
    et al.
    Universidade de Aveiro, Portugal.
    Elmgren, Fredrik
    DeepVision AB, Linköping, Sweden.
    Frasheri, Mirgita
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Curuklu, Baran
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Yuan, Xin
    Universidad Politecnica de Madrid, Spain.
    Martínez, José-Fernán
    Universidad Politecnica de Madrid, Spain.
    Bastos, Joaquim
    Instituto de Telecomunicações - Pólo de Aveiro, Portugal.
    Rodriguez, Jonathan
    Universidade de Aveiro, Portugal.
    Pinto, Marc
    ECA Robotics, France.
    Algorithms for the Detection of First Bottom Returns and Objects in the Water Column in Side-Scan Sonar Images2017In: OCEANS '17 A Vision for our Marine Future OCEANS '17, Aberdeen, United Kingdom, 2017Conference paper (Refereed)
    Abstract [en]

    Underwater imaging has become an active research area in recent years as an effect of increased interest in underwater environments and is getting potential impact on the world economy, in what is called blue growth. Since sound propagates larger distances than electromagnetic waves underwater, sonar is typically used for underwater imaging. One interesting sonar image setting is comprised of using two parts (left and right) and is usually referred to as sidescan sonar. The image resulted from sidescan sonars, which is called waterfall image, usually has to distinctive parts, the water column and the image seabed. Therefore, the edge separating these two parts, which is called the first bottom return, is the real distance between the sonar and the seabed bottom (which is equivalent to sensor primary altitude). The sensory primary altitude can be measured if the imaging sonar is complemented by interferometric sonar, however, simple sonar systems have no way to measure the first bottom returns other than signal processing techniques. In this work, we propose two methods to detect the first bottom returns; the first is based on smoothing cubic spline regression and the second is based on a moving average filter to detect signal variations. The results of both methods are compared to the sensor primary altitude and have been successful in 22 images out of 25.

  • 84.
    Al-Salihi, Hayder
    et al.
    The Department of Informatics, King’s College London, UK.
    Van Chien, Trinh
    Linköping University, Department of Electrical Engineering, Communication Systems. Linköping University, Faculty of Science & Engineering.
    Le, Tuan Anh
    The Department of Design Engineering and Mathematics, Middlesex University, London, UK.
    Nakhai, Mohammad Reza
    The Department of Informatics, King’s College London, London, UK.
    A Successive Optimization Approach to Pilot Design for Multi-Cell Massive MIMO Systems2018In: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 22, no 5, p. 1086-1089Article in journal (Refereed)
    Abstract [en]

    In this letter, we introduce a novel pilot designapproach that minimizes the total mean square errors of theminimum mean square error estimators of all base stations (BSs)subject to the transmit power constraints of individual users inthe network, while tackling the pilot contamination in multicellmassive MIMO systems. First, we decompose the originalnon-convex problem into distributed optimization sub-problemsat individual BSs, where each BS can optimize its own pilotsignals given the knowledge of pilot signals from the remainingBSs. We then introduce a successive optimization approach totransform each optimization sub-problem into a linear matrixinequality form, which is convex and can be solved by availableoptimization packages. Simulation results confirm the fast convergenceof the proposed approach and prevails a benchmarkscheme in terms of providing higher accuracy.

  • 85.
    Al-Sheikhly, Yavor
    KTH, Superseded Departments, Teleinformatics.
    Implementing policy-based network management1999Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

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

  • 86.
    Altinkaya, Martin
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Ahmedi, Saman
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    SIP in an Interconnector and Service Provider Role2001Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

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

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

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

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

  • 87.
    Al-Zubaidy, Hussein Mohammed
    et al.
    KTH, School of Electrical Engineering (EES), Communication Theory.
    Dán, György
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Fodor, Viktoria
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Performance of in-network processing for visual analysis in wireless sensor networks2015In: Proceedings of 2015 14th IFIP Networking Conference, IFIP Networking 2015, IEEE conference proceedings, 2015Conference paper (Refereed)
    Abstract [en]

    Nodes in a sensor network are traditionally used for sensing and data forwarding. However, with the increase of their computational capability, they can be used for in-network data processing, leading to a potential increase of the quality of the networked applications as well as the network lifetime. Visual analysis in sensor networks is a prominent example where the processing power of the network nodes needs to be leveraged to meet the frame rate and the processing delay requirements of common visual analysis applications. The modeling of the end-to-end performance for such networks is, however, challenging, because in-network processing violates the flow conservation law, which is the basis for most queuing analysis. In this work we propose to solve this methodological challenge through appropriately scaling the arrival and the service processes, and we develop probabilistic performance bounds using stochastic network calculus. We use the developed model to determine the main performance bottlenecks of networked visual processing. Our numerical results show that an end-to-end delay of 2-3 frame length is obtained with violation probability in the order of 10-6. Simulation shows that the obtained bounds overestimates the end-to-end delay by no more than 10%.

  • 88. Ambat, S. K.
    et al.
    Chatterjee, Saikat
    KTH, School of Electrical Engineering (EES), Communication Theory.
    Hari, K. V. S.
    Adaptive selection of search space in look ahead orthogonal matching pursuit2012In: 2012 National Conference on Communications, NCC 2012, 2012, p. 6176852-Conference paper (Refereed)
    Abstract [en]

    Compressive Sensing theory combines the signal sampling and compression for sparse signals resulting in reduction in sampling rate and computational complexity of the measurement system. In recent years, many recovery algorithms were proposed to reconstruct the signal efficiently. Look Ahead OMP (LAOMP) is a recently proposed method which uses a look ahead strategy and performs significantly better than other greedy methods. In this paper, we propose a modification to the LAOMP algorithm to choose the look ahead parameter L adaptively, thus reducing the complexity of the algorithm, without compromising on the performance. The performance of the algorithm is evaluated through Monte Carlo simulations.

  • 89.
    Amin, Yasar
    et al.
    University of Engineering and Technology, Taxila, Punjab, Pakistan.
    Shao, Botao
    KTH, School of Information and Communication Technology (ICT), Electronic Systems. KTH, School of Information and Communication Technology (ICT), Centres, VinnExcellence Center for Intelligence in Paper and Packaging, iPACK.
    Chen, Qiang
    KTH, School of Information and Communication Technology (ICT), Electronic Systems. KTH, School of Information and Communication Technology (ICT), Centres, VinnExcellence Center for Intelligence in Paper and Packaging, iPACK.
    Zheng, Li-Rong
    KTH, School of Information and Communication Technology (ICT), Electronic Systems. KTH, School of Information and Communication Technology (ICT), Centres, VinnExcellence Center for Intelligence in Paper and Packaging, iPACK.
    Tenhunen, Hannu
    KTH, School of Information and Communication Technology (ICT), Electronic Systems. KTH, School of Information and Communication Technology (ICT), Centres, VinnExcellence Center for Intelligence in Paper and Packaging, iPACK.
    Electromagnetic Analysis of Radio Frequency Identification Antennas for Green Electronics2013In: Electromagnetics, ISSN 0272-6343, E-ISSN 1532-527X, Vol. 33, no 4, p. 319-331Article in journal (Refereed)
    Abstract [en]

    This article demonstrates in-depth electromagnetic analysis of a radio frequency identification tag antenna manufactured by inkjet printing technology on different paper substrates to achieve ultra-low cost flexible radio frequency identification tags using a novel hole-matching technique for reducing the consumption of substrate material, and conductive ink. Nevertheless, the electromagnetic properties of the paper substrate are vulnerable to various environmental effects. Thus, the proposed antenna design is optimized for consistent wideband performance throughout the complete UHF radio frequency identification band (860960 MHz) while presenting a greater degree of material insensitivity. An advanced antenna design methodological analysis is performed to accomplish an extended read range, while exhibiting benchmarking results when across cardboard cartons filled with metal or water containing objects.

  • 90.
    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 Institute of Technology, Faculty of Computing, Department of Communication Systems.
    Heegaard, Poul
    Norwegian Univ Sci & Technol, NOR.
    Video QoE Killer and Performance Statistics in WebRTC-based Video Communication2016Conference paper (Refereed)
    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.

  • 91.
    Amso, Julian
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Faienza, Achille
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    IPsec Intrusion Detection Analysis: Using data from an Ericsson Ethernet Interface Board2008Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

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

  • 92. Anand, K.
    et al.
    Ganapathy, S.
    Kulothungan, K.
    Yogesh, P.
    Kannan, Anand
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    A Rule Based Approach for Attribute Selection and Intrusion Detection in Wireless Sensor Networks2012In: International Conference On Modelling Optimization And Computing, Elsevier, 2012, p. 1658-1664Conference paper (Refereed)
    Abstract [en]

    In this paper, we propose a new rule based attribute selection algorithm for removing the redundant attributes which are used in decision making on intrusions in wireless sensor networks. This work focuses mainly on finding important attributes to find Denial of Service attacks. In addition, we used an enhanced MSVM classification algorithm that was developed by extending the existing MSVM algorithm. The experimental results show that the proposed methods provide high detection rates and reduce false alarm rate. This system has been tested using KDD'99 Cup data set.

  • 93.
    Anchora, Luca
    et al.
    IMT of Lucca.
    Badia, Leonardo
    Università degli Studi di Padova.
    Karipidis, Eleftherios
    Linköping University, Department of Electrical Engineering, Communication Systems. Linköping University, The Institute of Technology.
    Zorzi, Mikele
    Università degli Studi di Padova.
    Capacity Gains due to Orthogonal Spectrum Sharing in Multi-Operator LTE Cellular Networks2012In: Proceedings of the Ninth International Symposium on Wireless Communication Systems (ISWCS), 2012, p. 286-290Conference paper (Refereed)
    Abstract [en]

    Static spectrum allocation leads to resource wastage and inter-operator spectrum sharing is a possible way to improve spectrum efficiency. In this work, we assume that two cellular network operators agree upon sharing part of their spectrum, which can then be dynamically accessed by either of them in a mutually exclusive way. Our goal is to numerically assess the gain, in terms of cell capacity, due to such orthogonal spectrum sharing. Hence, we propose a centralized algorithm that performs coordinated scheduling, in order to numerically evaluate an upper bound on the achievable sum capacity. The algorithm is centralized and exploits complete information on both networks to perform the optimum allocation. The simulation results illustrate the impact of the multiuser diversity and the asymmetry in the traffic load among the networks on the overall achievable gain.

  • 94.
    Anchora, Luca
    et al.
    IMT of Lucca.
    Badia, Leonardo
    Università degli Studi di Padova.
    Zhang, Haibin
    TNO ICT.
    Fahldieck, Torsten
    Bell Labs, Alcatel-Lucent.
    Zhang, Jianshu
    Ilmenau University of Technology.
    Szydelko, Michal
    Wroclaw Research Centre EIT+ .
    Schubert, Martin
    Fraunhofer Institute for Telecommunications HHI.
    Karipidis, Eleftherios
    Linköping University, Department of Electrical Engineering, Communication Systems. Linköping University, The Institute of Technology.
    Haardt, Martin
    Ilmenau University of Technology.
    Resource Allocation and Management in Multi-Operator Cellular Networks with Shared Physical Resources2012In: Proceedings of the Ninth International Symposium on Wireless Communication Systems (ISWCS), IEEE , 2012, p. 296-300Conference paper (Refereed)
    Abstract [en]

    In this paper, we focus on next-generation cellular networks and discuss physical resources sharing among the operators. This implies cooperative usage of the available radio frequencies and also infrastructure sharing. In particular, we analyze the spectrum sharing gain achievable at different time scales and the main factors impacting on it. Then, we move towards a wider idea of resource sharing and consider a joint spectrum and infrastructure sharing (full sharing). We describe a two-layer resource management architecture that enables operators to reduce costs while still guaranteeing a good service level. The main findings of our investigations are to quantify the effectiveness of resource sharing and open up new perspectives for the operators of next-generation networks.

  • 95. Andersen, O.
    et al.
    Wisell, David
    KTH, School of Electrical Engineering (EES), Signal Processing. University of Gävle, Sweden.
    Keskitalo, N.
    Stenvard, P.
    Cost effective high performance modular instrumentation, signal generation and signal analysis for future mobile communication systems2007In: 2007 IEEE Autotestcon, IEEE , 2007, p. 660-668Conference paper (Refereed)
    Abstract [en]

    A decrease in life cycle cost is a key issue for testing of mobile communication systems. The rapid development and edge technology requires high performance instruments and state of the art measurement technology. It is desired to use virtual/synthetic instruments and put the measurement technology in software independent of hardware, i.e. software driven measurements. Increased flexibility and modularization, both in hardware and software, are requirements to support the cost decrease. The hardware basis is signal generation and signal analysis. In this paper state of the art signal generation and signal analysis capabilities are demonstrated in a modular and flexible architecture. A direct IF synthesis is used to generate 1 WideBand Code-Division Multiple Access (WCDMA) carrier with more than 72 dB Adjacent Carrier Leakage Ratio (ACLR) 2 carrier with more than 68 dBc ACLR over a total bandwidth of 100 MHz. The signal analysis capabilities, ACLR performance, for a WCDMA carrier is better than -70 dBc and for a continuous wave better than -85 dBc over a bandwidth of 42.5 MHz. The critical down converter in the set up doesn't degrade the performance.

  • 96.
    Andersson, Dan
    KTH, School of Technology and Health (STH), Data- och elektroteknik.
    Implementation av prototyp för inomhuspositionering2013Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

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

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

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

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

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

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

  • 98.
    Andersson, Johan
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Kleihs, Marcus
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Routing Interior2013Student paper second term, 5 credits / 7,5 HE creditsStudent thesis
    Abstract [sv]

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

  • 99.
    Andersson, Martin
    Linköping University, Department of Electrical Engineering, Information Coding.
    Parametric Prediction Model for Perceived Voice Quality in Secure VoIP2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

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

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

  • 100.
    Andersson, Martin
    University of Skövde, School of Humanities and Informatics.
    SANDBUNKERSEGMENTERING FÖR SMARTPHONES: Automatisk positionsuppskattning av sandbunkrar för smartphone som golfcaddie2011Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

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

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

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

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

    bildsegmenteringsalgoritm går att slippa det manuella arbetet med att lägga in

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

    satellitbilder som smartphonen kan ladda ned via dess Internetanslutning. Golfaren

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

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

    hittar den framtagna segmenteringsalgoritmen cirka 70 % av sandbunkrarna på en

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

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

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

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

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

    timmar.

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

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

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

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

    golfbanan som vattenhinder och greener.

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