Change search
Refine search result
12 1 - 50 of 59
CiteExportLink to result list
Permanent link
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Abad Camarero, Daniel
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Performance analysis of IPv4 / IPv6 protocols over the third generation mobile network2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

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

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

  • 2.
    Afridi, Ayaz Khan
    KTH, School of Electrical Engineering (EES), Communication Networks.
    MACRO AND FEMTO NETWORK ASPECTS FOR REALISTIC LTE USAGE SCENARIOS2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 3.
    Ahmad, Muhammad Bilal
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Macro and Femto Network Aspectsfor Realistic LTE usage scenarios with Interference Management2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 4.
    Amoozadeh, Mani
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Certificate Revocation List Distribution in Vehicular Communication Systems2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Message exchange in VANETs should be secured. Researchers have designed many methods to meet this goal. One of the ways agreed upon by most researchers, is through the use of a public-key infrastructure (PKI). An important part of any PKI system is certificate revocation. The revocation is usually done by periodically issuing a Certificate Revocation List (CRL) by the Certification Authority (CA). After the creation of a CRL by CA, the CRL should be distributed in the VC system. The important question is how we can distribute the CRL efficiently and in a timely manner throughout the system in a way that all vehicles receive a genuine copy of it. A couple of researches considered CRL distribution in the past and proposed different methods like RSU-only [1], C2C Epidemic [2], and Most Pieces Broadcast (MPB) [3]. We implement the aforementioned CRL distribution methods and evaluate them using a common framework. With this approach, we can compare these methods accurately and point out the limitations of each. Due to the fact that C2C Epidemic did not provide any packet-level implementation, we propose an implementation for it. We also propose a new method for CRL distribution called ICE (Intelligent CRL Exchange). This method uses V2V and I2V communication to distribute the CRL pieces to vehicles. ICE is an enhanced version of the MPB method and it uses semi-incremental CRL exchange. With this approach, the number of duplicate received pieces decreases in comparison to the MPB method. Moreover, ICE uses a simple approach to decrease the number of unnecessary broadcasts by RSUs. The evaluation is done through simulations. OMNET++ [4] and the MiXiM framework are used for detailed packet-level simulation. The simulation is done for both small and large scale scenarios. For the large scale simulation, we use SUMO [5] to generate mobility traces of vehicle nodes. Different criteria are defined so that we can compare CRL distribution methods. According to the simulation results, vehicles in C2C Epidemic, MPB and ICE receive all the required CRL pieces in less time in comparison to RSU-only, because vehicles use both I2V and V2V communications. MPB shows a better performance than C2C Epidemic, but the number of duplicate received pieces increases substantially. ICE tries to alleviate this by incorporating semi-incremental CRL exchange. Furthermore, the number of broadcasts by RSUs in the ICE method shows reduction.

  • 5.
    Anisseh, Sara
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Internet Topology Characterizationon on AS Level2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This study investigates the Internet topology characterization on AS level driven from Border Gateway Protocol (BGP) tables which are collected from Réseaux IP Européens (RIPE) datasets during the seven year period, from 2003.07.30 to 2010.07.30.

    The investigation shows that despite of the growth of the Internet with lack of centralized control, some properties of the Internet follow certain rules and some properties remain the same during years. It demonstrates that the Internet, on AS level, exists in the form of clusters of ASs and the connected ASs with higher connectivity become even more connected during time. The spectral analysis of adjacency and normalized Laplacian matrix shows that the eigenvalues of both matrixes follow power-laws with high correlation coefficient with no considerable change in exponent values during years.

  • 6.
    Atiiq, Syafiq Al
    KTH, School of Electrical Engineering (EES), Network and Systems engineering.
    Adaptive Counteraction Against Denial of Service Attack2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

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

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

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

  • 7.
    Bai, Xueyao
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Distributed Visual Processing Based On interest Point Clustering2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this master thesis project, we study the problem in Visual Sensor Networks

    in which only limited bandwidth is provided. The task is to search for ways to

    decrease the transmitting data on the camera side, and distribute the data to dif-

    ferent nodes.

    To do so, we extract the interest points on the camera side by using BRISK in-

    terest point detector, and we distribute the detected interest points into di erent

    number of processing node by implementing proposed clustering methods, namely,

    Number Based Clustering, K-Means Clustering and DBSCAN Clustering.

    Our results show it is useful to extract interest points on the camera side, which

    can reduce almost three quarters of data in the network. A step further, by imple-

    menting the clustering algorithms, we obtained the gain in overhead ratio, interest

    point imbalance and pixel processing load imbalance, respectively. Specically,

    the results show that none of the proposed clustering methods is better than oth-

    ers. Number Based Clustering can balance the processing load between di erent

    processing nodes perfectly, but performs bad in saving the bandwidth resources.

    K-Means Clustering performs middle in the evaluation while DBSCAN is great in

    saving the bandwidth resources but leads to a bad processing balance performance

    among the processing nodes.

  • 8.
    Canat, Mert
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Enterprise Architecture Success Factors2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Enterprise architecture aligns organizations business processes, information systems andtechnical layers. Its role has become more challenging than ever before with the modern dayrapidly changing environment and technological advances. Considering these aspects, this thesistries to evaluate the success factors that affect enterprise architecture management.The thesis is done at Volvo Cars, in collaboration with Ferrologic. Twelve success factorssignificant for Volvo Cars’ enterprise architecture management are defined after a series of semistructuredinterviews with architects working at the company. This is followed by a surveyevaluating the factors sent to architects throughout Sweden. In the end, the factors are dividedinto four groups according to their impact level. The survey reveals that the businessunderstanding of the technical side, requirement definitions & handling requirement changes,high-level management involvement, and cross-functionality are perceived to be most impactfulsuccess factors for the industry professionals, in no particular order.

  • 9.
    Carosi, Robert
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Protractor: Leveraging distributed tracing in service meshes for application profiling at scale2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Large scale Internet services are increasingly implemented as distributed systems in order to achieve fault tolerance, availability, and scalability. When requests traverse multiple services, end-to-end metrics no longer tell a clear picture. Distributed tracing emerged to break down end-to-end latency on a per service basis, but only answers where a problem occurs, not why. From user research we found that root-cause analysis of performance problems is often still done by manually correlating information from logs, stack traces, and monitoring tools. Profilers provide fine-grained information, but we found they are rarely used in production systems because of the required changes to existing applications, the substantial storage requirements they introduce, and because it is difficult to correlate profiling data with information from other sources.

    The proliferation of modern low-overhead profilers opens up possibilities to do online always-on profiling in production environments. We propose Protractor as the missing link that exploits these possibilities to provide distributed profiling. It features a novel approach that leverages service meshes for application-level transparency, and uses anomaly detection to selectively store relevant profiling information. Profiling information is correlated with distributed traces to provide contextual information for root-cause analysis. Protractor has support for different profilers, and experimental work shows impact on end-to-end request latency is less than 3%. The utility of Protractor is further substantiated with a survey showing the majority of the participants would use it frequently

  • 10.
    Chareonvisal, Tanakorn
    KTH, School of Electrical Engineering (EES), Communication Theory.
    ImplementingDistributed Storage System by Network Coding in Presence of Link Failure2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Nowadays increasing multimedia applications e.g., video and voice over IP, social networks and emails poses higher demands for sever storages and bandwidth in the networks. There is a concern that existing resource may not able to support higher demands and reliability. Network coding was introduced to improve distributed storage system. This thesis proposes the way to improve distributed storage system such as increase a chance to recover data in case there is a fail storage node or link fail in a network.

    In this thesis, we study the concept of network coding in distributed storage systems. We start our description from easy code which is replication coding then follow with higher complex code such as erasure coding. After that we implement these concepts in our test bed and measure performance by the probability of success in download and repair criteria. Moreover we compare success probability for reconstruction of original data between minimum storage regenerating (MSR) and minimum bandwidth regenerating (MBR) method. We also increase field size to increase probability of success. Finally, link failure was added in the test bed for measure reliability in a network. The results are analyzed and it shows that using maximum distance separable and increasing field size can improve the performance of a network. Moreover it also improves reliability of network in case there is a link failure in the repair process.

  • 11.
    Charoenkulvanich, Hatairatch
    et al.
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Fathali, Farnaz
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Human-Mobility Modeling for Cellular Networks2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    With the rapid growth of usage of mobile devices and their applications and the ever increasing use of these technologies, optimizing the performance of cellular networks becomes inevitable. Considering the fact that mobile devices are carried by humans, we can conclude that the performance of cellular networks depends on the characteristics of human mobility. Therefore, understanding the basic characteristics of human mobility and designing realistic models based on this understanding can help in optimizing the performance of cellular networks in terms of managing node or base station capacity, handling handoffs, paging, location updating, etc. In this work, we review the most important human mobility characteristics that are extracted from real human mobility traces. We then propose asynthetic model that can produce human traces; we verify the model to examine if it cancapture all the introduced characteristics. The model is designed as a graph in which nodes represent the visit-points and edges are considered as the roads between these visit-points. We focus on keeping the structure of the model close to reality following hierarchical traffic systems. The model is implemented in a simulator to be validated. The results show that our model does not capture all the characteristics as expected. To be precise, the model does not create truncated power-law flight lengths or truncated power-law radius of gyration. Our experiments, verifying our assumptions, show that the algorithms used for defining the area that the user can move within, and also choosing the next destinations, result in a sharing-area among users: the sharing-area is the common set of visit-points that all users usually choose to visit. The existence of this sharing-area is the reason that the results are not as expected. We suggest that for future work, it is interesting to improve the model by changing the way of the user-area selection and the next destination selection with consideration of distance together with visit-point weight.

  • 12.
    Chatzis, Vasileios
    KTH, School of Information and Communication Technology (ICT).
    SDN Benefits in a Legacy World2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This dissertation aims to explore how one could leverage Software Dened Network (SDN) and Network Function Virtualization (NFV) principles in order to realize Service Function Chaining (SFC) in a network. SDN is a new networking paradigm, which makes a network programmable through the use of a software entity called SDN controller. NFV is intended to enable deployment of virtualized network functions, therefore replacing existing hardware solutions. SFC provides the ability to route user traffic to one or more network functions in an orderly manner. SFC will potentially enable many use cases such as data providers being able to dynamically steer user traffic through a set of network functions such as rewall and loadbalancer.

    This study is based on a set of goals. These goals evolve around the implementation of a prototype that will enable a SDN controller to steer user traffic through a series of virtualized network functions (VNFs). An important part of the prototype setup is a Network Management Software (NMS) named BECS, which is developed by Packetfront Software AB. BECS is acting as an orchestrator on the network and has complete awareness of all the network devices present on the network it manages. One of the main requirements of the prototype is to enable BECS to communicate with a SDN controller. Once that has been achieved, BECS could provide the necessary information that the controller needs in order to create and install a set of forwarding rules in the SDN enabled switches of the network. All those steps are necessary in order to achieve SFC. In this prototype, SFC is realized by demonstrating the user specific traffic steering through a set of VNFs in a specific order, based on control messages originated from BECS.

    Until now, network architecture has been limited to the capabilities of the actual hardware equipment. SDN and NFV help us to overcome this limitation. Information needs to be available anywhere and at any time, in a reliable and secure way. To ensure that, we propose a new scheme of network architecture through our prototype solution. This solution intends to give the ability to network managers to re-shape their networks based on their needs by the use of SFC.

  • 13.
    Chaudry Aamer, Sattar
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Design and Evaluation of Mobile-to-Mobile Multimedia Streaming using REST-based Mobile Services2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Today, it has become conveniently possible to host Web Services (WS) on mobile node using a Mobile Web Server (MWS). To address a vast range of use cases, these hosted mobileWS may be implemented to offer synchronous and asynchronous execution styles depending upon the requirements of mobile application. Thus, the MWS actually provides the necessary architectural capabilities to handle and process incoming requests for each class of service. But, it is very vital for these servers to simplify the service access and creation mechanisms, so that, the processing overheads on the hosting node are reduced. Previously, research has shown promising optimizations in MWSprocessing by using theREST architecture style for service access and creation. However, the mobile WSoffered by the existingMWSusesXML based payload for information exchange, which restricts the incorporation of the rich multimedia content, such as, audio and video data. As a consequence, the true potential of the REST -based server architecture is not utilized. This thesis addresses architectural and transport layer issues to enable the exchange of rich multimedia content between mobile nodes using mobile WS over the live wireless data networks. The research work is focused on the implementation of multimedia streaming protocol standards, such as, the RTSPand theRTP, into the existingREST-basedMWS architecture. Also, to enable the controlled Mobile-to-Mobile (M2M) media streaming capabilities, the thesis uses both TCP and UDP as transport layer protocols for signaling and data transmission, respectively. The control functions are implemented by mapping the synchronous and asynchronous mobile WS to the RTSPmethods. The implementation extends the states of the asynchronous mobileWS to offer these multimedia control functions. The issues related to the firewalls and Network Address Translation (NAT) are addressed by the development of an Intermediate Access Gateway (IAG),which offers the functionality based on the STUNandTURN concepts. This work enables mobile WS basedM2M media streaming either through the directly established connection with the peers, or via the IAG. Thus, the developed proof-of-concept prototype demonstrates the streaming capabilities of the extended MWS architecture over any wireless data networks.

  • 14.
    Chen, Zhaofei
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Opportunistic Crowdsourcing for Collective Music Sharing2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The fast spreading of smart mobile devices has changed the way people create and share multimedia content. Infrastructure networks, such as 802.11 and cellular, can provide users Internet access to disseminate this content, however their services may be limited due to insufficient deployment of infrastructure equipment, network congestion as downloading of large-size multimedia content becomes highly prevalent, or simply high prices that prevent users from utilizing these services. Middleware architectures have been designed and implemented on smart mobile device platforms to distribute content opportunistically when devices are within each other's communication range: mobile devices can either utilize connections to fixed infrastructure, such as public access points when in range, or distribute content to other devices directly in ad hoc fashion when in proximity. In this work we have designed and implemented a real-time music-sharing application that utilizes a content-centric opportunistic networking middleware. The application provides an interface for users to publish audio files stored in their own mobile devices to a subscriber jukebox that is within their communication range. The jukebox then plays the audio file that is first in queue in its playlist by streaming it from the publisher user device. User devices are synchronized with the playlist in the jukebox so that users can observe the contents of the playlist on their own displays in real-time.

  • 15.
    Chupisanyarote, Sanpetch
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Content Caching in Opportunistic Wireless Networks2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Wireless networks have become popular in the last two decades and their use is since growing significantly. There is a concern that the existing resource of centralized networks may not sufficiently serve the enormous demand of customers. This thesis proposes one solution that has a potential to improve the network. We introduce decentralized networks particularly wireless ad-hoc networks, where users communicate and exchange information only with their neighbors. Thus, our main focus is to enhance the performance of data dissemination in wireless ad-hoc networks.

    In this thesis, we first examine a content distribution concept, in which nodes only focus on downloading and sharing the contents that are of their own interest. We call it private content and it is stored in a private cache. Then, we design and implement a relay-request caching strategy, where a node will generously help to fetch contents that another node asks for, although the contents are not of its interest. The node is not interested in these contents but fetches them on behalf of others; they are considered public contents. Thesepublic contents are stored in a public cache. We also propose three public caching options for optimizing network resources: relay request on demand, hop-limit, and greedy relay request. The proposed strategies are implemented in the OMNeT++ simulator and evaluated on mobility traces from Legion Studio. We also campare our novel caching strategy with an optimal channel choice strategy. The results are analyzed and they show that the use of public cache in the relay request strategy can enhance the performance marginally while overhead increases significantly.

  • 16.
    Devici, Dogukan
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Consensus performance in sensor networks2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 17.
    Dhainaut, Guillaume
    KTH, School of Electrical Engineering (EES), Communication Networks.
    A reverse proxy for VoIP: Or how to improve security in a ToIP network2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The need for security is crucial in Telephony over IP (ToIP). Secure protocols have been designed as well as specific devices to fulfill that need. This master thesis examines one of such devices called Session Border Controller (SBC), which can be compared to reverse proxies for ToIP. The idea is to apply message filters to increase security.

    This thesis presents the reasons of SBC existence, based on the security weaknesse sa ToIP network can show. These reasons are then used to establish a list of features which can be expected from a SBC and discuss its ideal placement in a ToIP network architecture. A test methodology for SBCs is established and used on the free software Kamailio as an illustration. Following this test, improvements of this software, regarding threats prevention and attacks detection, are presented and implemented.

  • 18.
    Faradjzadeh, Navid
    KTH, School of Electrical Engineering (EES), Communication Networks.
    A Tool For Online Packet Analysis InMobile Networks2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Today the mobile networks face a high demand for packet data delivery at ever increasing rates. In order to satisfy the demand, new network modules and protocols are introduced into mobile networks. This leads to a complex system of protocols and algorithms. This level of complexity requires efficient methods of troubleshooting. This need has motivated the implementation of more efficient packet analizers besides the ones that already exist today. A number of packet analizers have already been introduced in order to read the data from the wires and dissect them into packets but the process of reading binary data and dissecting them is a multistage procedure. In this project we tried to propose a more efficient solution to packet analizing in mobile networks domain. Packet analizers that already exist can dissect a packet provided that it is a full packet or in case that there is an absent header the user must be aware of the type of the header and add it to the packet manually and then hand it over to a packet analizer for dissection. However, here in this project we implemented a packet analizer that can dissect any headers extracted from a packet without the need to have prior information on the type of the absent headers.

    In this report we describe the types of protocols that our solutions potentially can support then we discuss the requirements and constraints of such a tool. We give a description of the design and implementation of the software and finally we discuss some improvements on the performance of our solution.


  • 19.
    Ghanbari, Amirhossein
    KTH, School of Information and Communication Technology (ICT).
    Indoor multi-operator solutions, Network sharing and Outsourcing network management and operation2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 20.
    Ghanbari, Amirhossein
    KTH, School of Information and Communication Technology (ICT).
    Indoor multi-operator solutions Network sharing and Outsourcing network management and operation2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Indoor solutions as a part of cellular mobile networks planning have been used for years in a way to fulfill the lack of admissible coverage while subscribers experienced using cellular phones indoors. On the other hand, network capital and operational expenditures; that has also commonly been used for Distributed Antenna Systems (DAS) solutions in indoor deployments. Besides sharing, outsourcing network operation and maintenance has also been widely accepted by wireless carriers all around the world after that IT outsourcing flow, which started in late 90s, seemed to be quite promising for lowering operational costs.

    The raise of new technologies in this domain that always promise higher, better and more to subscribers, little by little started to become worrisome since operators have begun to experience lower revenues from voice services during the last couple of years as well as higher demand of capacity. As a result, operators started considering deploying indoor networks as a part of their planned network, with regard to the fact that during recent years the femtocell technology became the hot topic for smallcell deployments. This way, MNOs could exploit benefits of covering customers indoors efficiently as well as offloading mobile data traffic from macro cellular networks. But a question rose afterwards; why sharing and outsourcing in smallcell networks have not taken off yet? As they have been commonly used in macro cellular networks and DAS solutions?

    In this MSc thesis, cooperation between different actors of the shared indoor mobile network ecosystem is studied by investigating both possible sharing models and the concept of outsourcing network operation and management for smallcell networks. This investigation has been done based on femtocells as the most suitable technology both for better coverage and higher capacity. During this process, different roles of actors in the ecosystems, the business relations between them and the main drivers of sharing were studied as well as discussing the main beneficiary of sharing, in order to find different types of cooperation and correlation in the ecosystem.

    The main research questions in the thesis revolve around absence of sharing either active or passively in indoor mobile networks as well as outsourcing network operation and management. Eventually, a series of possible deployment models for shared and outsourced indoor mobile networks are presented where they have been tried to be verified by a number of use cases. As a result, this study proposes a set of recommendations for different possible operators in the ecosystem in order to formulate a profitable business model for them. These recommendations are believed to enable taking of f sharing and outsourcing in smallcell networks.

  • 21.
    Girmay Mesele, Asmelash
    KTH, School of Electrical Engineering and Computer Science (EECS).
    AUTOSARLang: Threat Modeling and Attack Simulation for Vehicle Cybersecurity2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The rapid growth and development of the Information and Communications Technology attract many industries including the automotive industry. Since the last four decades, the automotive engineering has been impacted by the Information Technology. Nowadays, modern vehicles are being designed with up to hundreds of electronic control units (ECUs) and be able to communicate with other vehicles, infrastructure, and other things via wireless networks and sensors. For such in-vehicle networks, serial bus systems like CAN bus, LIN bus, FlexRay, and MOST are standardized. Parallel to this, the automotive industry vendors designed and standardized automotive open systems architecture (AUTOSAR) software platform. AUTOSAR has two main standards - the classical platform and adaptive platform. The classical platform (CP) is designed for the current embedded ECUs, whereas the adaptive platform (AP) is being designed for the future intelligent ECUs. The intelligent AP ECU constitute many multi-processing processors and Ethernet to realize the future autonomous vehicles.On the other hand, automotive industries shall ensure “safety first” in their design and regard it as part of their market feature. Directly or indirectly, the safety of the modern connected vehicles is related to their cybersecurity. Today, cybersecurity professionals are conducting researches to bring remarkable solutions to the sophisticated cyberattacks. One approach of cybersecurity solution is to make a cyber threat modeling and attack simulations. Example, meta-attack-language (MAL) is a threat modeling and attack simulation language, which is designed to make domain-specific threat analysis.In this study, potential assets of an automotive vehicle with AP ECUs are identified. Then, threats of each identified asset are collected from different literature. With both inputs, a cyber threat model is written using MAL. Finally, validation of the model is made with a simulation language. Consequently, modern vehicle with AP ECUs is modeled and simulated.This study contributes four important things - list of potential assets that AP running vehicle constitutes, collected list of threats of the identified assets, validated cyber threat model, and simulation test cases for each potential attack paths in the model.

  • 22.
    Hamadeh, Anas
    KTH, School of Electrical Engineering and Computer Science (EECS), Information Science and Engineering.
    Anomaly Detection in A Multivariate DataStream in a Highly Scalable and Fault Tolerant Architecture2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The process of monitoring telecommunication systems performance by investigatingKey Performance Indicators (KPI) and Performance Measurements(PMs) is crucial for valuable sustainable solutions and requires analysts' interventionwith profound knowledge to help mitigate vulnerabilities and risks.This work focuses on PMs anomaly detection in order to automate the processof discovering unacceptable Radio Access Network (RAN) performance byleveraging K-meansjj algorithm and producing an anomaly scoring mechanism.It also oers a streaming, fault tolerant, scalable and loosely coupled architectureto process data on the y based on a normal behavior model. Theproposed architecture is used to test the anomaly scoring system where variousdata patterns are ingested. The tests focused on inspecting the anomaly score'sconsistency, variability and sensitivity. The results were highly impacted by thereal-time standardization process of data, and the scores were not entirely sensitiveto changes in constant features; however, the experiment yielded acceptableresults when the correlation between features was taken into account.

  • 23.
    Hassanzadeh, Navid
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Scalable Data Collection for Mobile Wireless Sensor Networks2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In the near future WSNs (wireless sensor networks) which consist of tiny wireless embedded systems will be an inseparable part of our daily lives. Data collection, collecting data from a large number of sources to one or more base stations, is a typical application for WSNs. A substantial number of data collection algorithms have been specifically designed for static scenarios while there are some scenarios in which sensor nodes are attached to intrinsically mobile objects. Generally, in such scenarios delay tolerant networking approaches have been exploited for offline data analysis. However, in-situ dta collection from mobile scenarios has received little attention.

    We propose Mobile Collect to address the limitations of static data collection protocols in mobile scenarios. For this purpose, Collection Tree Protocol (CTP), a de facto standard for data collection, which is implemented in Contiki-OS (Contiki Collect), has been optimized to avoid loops and to react quickly to topology changes which occur frequently in mobile scenarios. The MAC (Medium Access Control) layer in WSNs has a decisive impact on the overall performance of mobile networks in terms of power consumption, and packet delivery rate. We have evaluated Mobile Collect protocol with a receiver-initiated (A-MAC that we implemented in Contiki-OS) and a sender-initiated (Contiki-MAC) MAC protocol.

    Compared to the Contiki Collect and the recently proposed DYMO (Dynamic MANET On-demand) protocol, MObile Collect with Contiki-MAC shows a significant improvement in reliability while it has a slight increase in power consumption. A-MAC slightly improves reliability for sparse topologies, but has higher power consumption.

  • 24.
    Hawasli, Ahmad
    KTH, School of Electrical Engineering and Computer Science (EECS).
    azureLang: a probabilistic modeling and simulation language for cyber attacks in Microsoft Azure cloud infrastructure2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Cyber-attack simulation is a suitable method used for assessing the security ofnetwork systems. An attack simulation advances step-wise from a certain systementry-point to explore the attack paths that lead to dierent weaknesses inthe model. Each step is analyzed, and the time to compromise is calculated.Attack simulations are primarily based on attack graphs. The graphs areemployed to model attack steps where nodes can represent assets in the system,and edges can represent the attack steps. To reduce the computational cost associatedwith building an attack graph for each specic system, domain-specicattack languages, or DSL for short, are used.The nal product of this thesis work is azureLang, a probabilistic modelingand simulation language for modeling Microsoft Azure cloud infrastructure.AzureLang is a DSL which denes a generic attack logic for MicrosoftAzure systems. Using azureLang, system administrators can easily instantiatespecic-system scenarios which emulate their Microsoft Azure cloud system infrastructure.After creating the model, attack simulation can be run to assessthe security of the model.

  • 25.
    Heyi, Binyam Shiferaw
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Implementation of Indoor Positioning using IEEE802.15.4a (UWB)2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Indoor positioning is a technique that is used to locate a mobile device in indoor environment in real or near real-time. The demand for indoor positioning system as a location based system is becoming more and more widespread. However, the field has not gain much success as outdoor positioning system.

    The objective of this thesis work is to design and implement an indoor positioning system that relies on ultra wide band technology. The report also describes the way how to implement IEEE802.15.4a physical layer and medium access layer .The system uses time difference of arrivals technique to estimate the position of the mobile device.

    Through an evaluation of our system, we conclude that ranging can reach an accuracy of ±20cm in line of sight measurement and ± 50cm for non-line of sight measurement. But the localization that is achieved has an accuracy is up to ±1.1m, we believe this can be improved by having all device to be synchronized effectively.

  • 26.
    Hosseini Hooshyar, Sima
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Feasibiity analysis of MBMS deployment with the introduction of LTE2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Multimedia Broadcast Multicast service (MBMS) proposed by 3GPP for efficient use of network resources in broadcast and multicast services, provides the operator a delivery mechanism to simultaneously send to multiple recipients at high speed. Although MBMS was introduced in 3GPP Release 6 at the time of 3G networks, the MBMS feature did not find much attention from the 3G network operators. This thesis studies the technical and market feasibility for a successful MBMS deployment today at the time of commercial LTE deployment. UE and RAN advancements that make MBMS technologically feasible are studied together with the market feasibility factors such as user demand on media streaming and the impending data explosion.

    The thesis concludes that today at the time of LTE, it is more feasible from both technology and market perspectives to deploy MBMS in comparison to the time of 3G. As a future work, the thesis provides some suggestions that the operators should take care of before deploying MBMS.

  • 27.
    Jiang, Zuoying
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Predicting Service Metrics from Device Statistics in a Container-Based Environment2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Service assurance is critical for high-demand services running on telecom clouds. While service performance metrics may not always be available in real time to telecom operators or service providers, service performance prediction becomes an important building block for such a system. However, it is generally hard to achieve. 

    In this master thesis, we propose a machine-learning based method that enables performance prediction for services running in virtualized environments with Docker containers. This method is service agnostic and the prediction models built by this method use only device statistics collected from the server machine and from the containers hosted on it to predict the values of the service-level metrics experienced on the client side. 

    The evaluation results from the testbed, which runs a Video-on-Demand service using containerized servers, show that such a method can accurately predict different service-level metrics under various scenarios and, by applying suitable preprocessing techniques, the performance of the prediction models can be further improved. 

    In this thesis, we also show the design of a proof-of-concept of a Real-Time Analytics Engine that uses online learning methods to predict the service-level metrics in real time in a container-based environment.

  • 28.
    Karamanos, Emmanouil
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Investigation of home router security2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Home routers are common in every household that has some kind of Internet connectivity. These embedded devices are running services such as web, file and DHCP server. Even though they have the same security issues as regular computers, they do no run protection software such as anti-virus and they are not updated. Moreover, the importance of these devices is misjudged; all network traffic is passing through them and they control the DNS of the network while, in most cases, they are on-line around the clock. When more and more non-Internet features are implemented into home routers, such as Voice over IP and network storage, their role becomes more special and many security concerns are raising. In this thesis, we investigate the issues resulting from this special role; the importance for these devices to be secure, the attacking vector and how the devices can be compromised to be part of a large home router botnet. We conclude by proposing ways to make the current implementation more secure, suggesting ways to protect routers from botnets without user interaction, that is from the ISP, while respecting the privacy of the end user and we identify what future work needs to be done.

  • 29.
    Karthikeyan, Siddharth Rathinam
    KTH, School of Information and Communication Technology (ICT).
    Mobile Payments: A Comparative study between European and Non-European Markets2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    ‘Mobile Payments’ is a new technological mantra not only for researchers, innovators, company executives, but also for every household across the globe. True to the statement, Mobile payments are in the verge of taking a giant leap towards a cashless society. Accordingly, mobile payment services are still followed in both developed and developing countries. In the developing economies, mobile based payment services has reached a pinnacle of success in a short span of time due to the favouring conditions such as very few banked people with more mobile phone penetration etc. But in the developed markets such as Europe, USA etc., with more advanced technology and payment solutions find it difficult to reach a steady growth.

    In this thesis, the main objective is to find out the factors that are hindering the uptake of mobile payments in European market. This is done by comparing the Non-European market with the European one and analysing the factors for success in the developing market and this success factors are considered for the European market which can be the lessons learnt for a better uptake of mobile payments. For this, four countries are selected in each of the markets. This analysis is made by diving into two phases. In the first phase, different cases of mobile payment present in both the markets are taken and analysed. In the second phase, factors considered for influencing the success of mobile payments such as Socio-economic conditions, Technology and Hardware used, Actors involvement, Pricing, Regulatory issues and Consumer acceptance are collected, analysed for both the markets.

    The analysis is done for two phases and for each phase a separate framework is used. Once the analyses are done, a summary of the results are produced. Based upon the summary of both the phases, the overlying factors causing success in Non-European market are identified and explained. Then they are compared with the European market to identify where certain suitable lessons can be learnt from the developing market. The identified factors are considered as the lessons to be learnt for a big break in mobile payment industry. In the future work section, Contactless mobile payments (CMP) is explained and their future scope in mobile payment ecosystem is discussed.

  • 30.
    Katsikeas, Sotirios
    KTH, School of Electrical Engineering and Computer Science (EECS).
    vehicleLang: a probabilistic modeling and simulation language for vehicular cyber attacks2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The technological advancements in the automotive industry as well as in thefield of communication technologies done the last years have transformed thevehicles to complex machines that include not only electrical and mechanicalcomponents but also a great number of electronic components. Furthermore,modern vehicles are now connected to the Wide Area Network (WAN) and inthe near future communications will also be present between the cars (Vehicleto-Vehicle, V2V) and between cars and infrastructure (Vehicle-to-Infrastructure, V2I), something that can be found as Internet of Vehicles (IoV)in the literature. The main motivations towards all the aforementioned changesin modern vehicles are of course the improvement of road safety, the higherconvenience of the passengers, the increase in the efficiency and the higher userfriendliness.On the other hand, having vehicles connected to the Internet opens them up toa new domain of interest, this no other than the domain of cyber security. Thispractically means that while previously we were only considering cyber-attackson computational systems, now we need to start thinking about it also forvehicles. This, as a result, creates a new field of research, namely the vehicularcyber security. However, this field does not only include the possible vehicularcyber-attacks and their corresponding defenses but also the modeling andsimulation of them with the use of vehicular security analysis tools, which isalso recommended by the ENISA report titled “Cyber Security and Resilienceof smart cars: Good practices and recommendations”.Building on this need for vehicular security analysis tools, this work aims tocreate and evaluate a domain-specific, probabilistic modeling and simulationlanguage for cyber-attacks on modern connected vehicles. The language will bedesigned based on the existing threat modeling and risk management toolsecuriCAD® by foreseeti AB and more specifically based on its underlyingmechanisms for describing and probabilistically evaluating the cyber threats ofthe models.The outcome/final product of this work will be the probabilistic modeling andsimulation language for connected vehicles, called vehicleLang, that will beready for future use in the securiCAD® software.

  • 31.
    Khalid, Usman
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Design and Implementation of a Network Search System2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    While modern communication networks have provided ease of connectivity and accessibility to vast resources, its operational and management task has become complex. Today’s communication networks consist of network devices from various vendors, which produce enormous amount of operational data in the form of SNMP traps, syslog messages, NetFlow caches, etc. It has become increasingly difficult for operational and fault management applications to utilize all the necessary information from the vast pool of information of varying formats. This report presents a prototype called

    Network Search System (NSS) that aims at easing the development of these applications by providing a simple, uniform interface to obtain network information that require no knowledge of location of the information. NSS abstracts the information collection and generalization processes by providing a query interface to the management applications to retrieve intended information. The report presents several use cases implemented using the system to demonstrate its functionality. It also presents performance evaluations, which point out the crucial bottlenecks in the system and are subject for further improvement of the system.

  • 32.
    Liu, Kui
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Performance Evaluation of ZigBee Network for Embedded Electricity Meters2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    ZigBee is an emerging wireless technology for low-power, low data rate and short range communications between wireless nodes, which is showing a promising future. This research provides an overview of 802.15.4 and ZigBee standard. A test bench was created to evaluate the performance of ZigBee network for electricity meters applications. The results from the test show that ZigBee supports a large network size, a range of 75m within line of sight, a fairly large effective data rate that is enough for metering traffic and very low power consumption devices. These characteristics are very suitable for electricity meters applications where cost and power consumption is the major concern.

  • 33.
    Maalouf, George Ludwig
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Evaluation of performance testing tools: Performance Center and BlazeMeter2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The need for performance testing is growing, and many companies are moving toward automated performance testing. Telia uses HP Performance Center for performance testing and wants to explore the market for new performance testing tools. The study compares two performance testing tools: HP Performance Center and BlazeMeter.The study is based on several criteria, which are cost, usability, functionality, efficiency and agile performance testing. The report contains information about the literature review that led to the creation of the framework and interview questions. The purpose of the report is to inform the reader about which tool has better usability, functionality, efficiency and costs and which tool can be used in agile performance testing.

  • 34.
    Mahmood, Azam
    KTH, School of Electrical Engineering (EES), Communication Networks.
    A Mobile Service Delivery Platform forWeb Classifieds2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The Mobidoo Mobile Service Delivery Platform (MSDP) provides opportunity to the service providers to add online services by creating classifieds and advertising them to end users. These services can either be provided free of cost or with cost. Users can facilitate from these services by showing their interest and can get that particular service from service provider via ADMIN authentication or can also just surf through the services available on mobile web application. Main users of the application are ADMIN, SERVICE PROVIDERS AND PUBLIC USER. Graphical User Interface was developed by HTML5, CSS3 and PHP5. Moreover, the facility of geolocation filter is also added. This application is web based and specifically designed for Mobile phones but it also runs on Desktop PCs. In short, this is an application that has made online shopping easier.

  • 35.
    Mazhar, Kashaf
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Compliance Procedures for Dynamic Adaptive Streaming over HTTP (DASH)2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    MPEG has been actively contributing towards the multimedia side in terms of storage and delivery of media content with flexible and advance file formats like the MPEG-2 transport stream and lately the MPEG 4 formats. Adaptive Streaming over HTTP is relatively a new genre in the area of streaming where this diverse content is delivered to TV’s, portable data units, smart phones, homes set top boxes etc. Most common of these streaming in practice are the apple live streaming, Smooth Streaming by Microsoft, HTTP Adaptive streaming as per the 3GPP specifications and the MPEG specified Dynamic Adaptive streaming over HTTP- (DASH). The technology is based on intelligence at clients end to cope up with variable network conditions and optimize the performance in an automated fashion.

    As the DASH specification is being finalized measures are to be taken to define criteria that will ensure the validation of a DASH process. Rules and conditions specified in the specification need to be followed by the client and server interaction as well as the content that will actually constitute the streaming process. This conformance is necessary to ensure the properties defined for a streaming process to provide the best user experience and performance efficiency. In light of this an initiative in this area of conformance testing is required so that the future  deployment and implementation of DASH has a baseline to follow. The initial outline lay out by MPEG and DASH is followed to formulate and later implement the rules for the interaction between the client and the server. Secondly the content used in streaming is also checked for properties and attributes mentioned in the MPD and the ones necessary for DASH process. These efforts will help define the criteria required for DASH validation as well as a ground work that can be extended for further work in this domain. In summary, the main tasks are - Development of last stage of the integrated software for MPD conformance stages (Java Script)

    - Formulation of Rules for Conformance from DASH specifications.

    - Extension to the existing Qualcomm DASH Reference software to support conformance test on media content level

    The thesis mainly concentrates on logs that are the result of conformance processing. The logs are analyzed to see the whether the condition specified are fulfilled or not. The process can be regarded as a ‘YES’ or ‘NO’ result indicating the fault/error that occurred.

  • 36.
    Meenakshi Sundaram Gandhi, Praveen Kumar
    KTH, School of Information and Communication Technology (ICT).
    GNU Radio + USRP2 Implementation of a Single-Carrier Zero-Correlation-Zone CDMA System2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    GNU Radio is a software defined radio in which components implemented in hardware are implemented using the software. GNU Radio works along with the USRP board. The USRP board is used to transmit and receive the signal in the wireless channel.

    CDMA system using the ZCZ (zero Correlation Zone) code is needed to be implemented in the GNU Radio and USRP board. Primary implementation and testing of CDMA using the ZCZ code is done with Matlab. The ZCZ come with the property of ideal impulsive auto correlation and zero cross correlation property within its ZCZ. However the Matlab implementation is not enough to make the system work using the USRP board. It is needed to be modified and implemented in GNU Radio to make the USRP board work.

    Unlike the simulation done in the Matlab there are lot of problems involved in real-time implementation of the idea in GNU Radio. In Matlab there are lot of in built functions which are needed to be implemented manually in C++. In GNU Radio a chunk of data received at a particular instant may not be of same length all the time and it keeps varying, should be handled properly. For the feedback implementation such as code tracking needed to be handled carefully and all the feedback variables needed to be present in a single module. ZCZ code for single user system, that is one transmitter and one receiver has worked well, but the ZCZ code for multi user uplink had to be tested too.

    This thesis aims at converting the Matlab implementation of ZCZ codes into real time GNU Radio implementation that works using the USRP board. This thesis will check the real time implementation of ZCZ code using USRP board and GNU Radio. This is done by implementing spreading of data at the sender side using ZCZ code, code synchronization at the receiver, code despreading at the receiver without code tracking and code despreading with code tracking are all done using ZCZ codes. This thesis also checks the feasibility of an asynchronous multi user communication without strict timing synchronization among the users with good results.

  • 37.
    Merve, Akis
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Temporal and Spatial Interference Correlations in Cognitive Radio Networks with Vertical Cooperation2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Cognitive radio technology provides a solution for the spectrum scarcity issue by allowing the unlicensed users which are the cognitive radio devices to share the licensed band with the licensed (primary) users. The abilities of cognitive radio device help the secondary (unlicensed) nodes to observe the licensed band and to adjust their transmission parameters for maintaining the primary communication since in cognitive radio networks, it is essential that the existence of the unlicensed users must not harm the licensed network. Under these circumstances, we consider vertical cooperative transmission where primary transmission is not severely damaged by the secondary interference since each primary pair (transmitter and receiver) selects a neighbor secondary user as a cooperative relay to assist their transmission. Cooperation provides an increase in the signal-tointerference-ratio (SIR) of the primary network which can be harnessed by the secondary network as an additional bandwidth for their communication. We propose three relay selection rules so the influence of the relay’s position over the temporal and spatial correlations can be evaluated for different network conditions. Additionally, we implement primary exclusive region (PER) for each primary pair in the network which covers primary nodes, and all secondary users locate inside the zone become inactive. According to the outage model proposed in paper [2], temporal and spatial correlations are assumed to be 1 and 0 respectively; however it is estimated that regarding the environmental factors and the relay’s location, these correlation values may vary. This thesis work is based on the validation of the assumptions provided in paper [2] and our results demonstrate that the temporal and spatial correlation values changes under different circumstances and with different relay selection rules. The simulation results also show that PER significantly stimulates the cooperation performance thereby increases the transmission quality of the primary network.

  • 38.
    Mestanov, Filip
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Analysis of Interoperability of 3GPP Radio Access and WLAN2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 39.
    Murtaza, Shahid
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Implementation and Evaluation of a JSON Binding for Mobile Web Services with IMS Integration Support2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Service Oriented Architecture SOA is a well recognized and immensely applied reference model for service oriented computing, both in industry and research. Because of its fastidious features, such as reusability, interoperability, scalability and flexibility a Web Based SOA is adopted, in the areas like Enterprise Application Integration EAI. These days the Web Based Services, such as XML Web Services are not limited to fixed servers but can also be deployed on mobile devices in order to enhance the capability to become the service provider as well, such Web Services are known as Mobile Web Services MobWS. With the limited capabilities of mobile devices, the performance of XML based Mobile Web Services is affected due to the requirements of XML manipulation and parsing over the Representational State Transfer REST architecture. This Thesis work aims to develop and design a lightweight JSON Binding using the REST architecture. This will enhance the REST architecture to enable service creation and management for the synchronous as well as for the asynchronous Mobile Web Services MobWS. Initially, the existing synchronous and asynchronous server architecture is analysed to establish the foundation of the JSON Framework. Then the JSON Binding is developed in conformance with the analysed architecture. Therefore, the existing XML messaging constructs are redefined and optimized by using the JSON. Additionally JSON Binding developed in this work is used to enable service consumption in the IMS. This work is done by developing IMS client side modules in the middleware using Ericsson’s Mobile Java Communication Framework (MJCF). Finally the performance analyses have been done to evaluate and compare the impact of JSON Vs XML Binding over the synchronous as well as for the asynchronous server architecture. Thus, the architectural capability of the MobWS middleware has been customized to select the appropriate content type to handle and process the client requests.

  • 40.
    Naguib, Mina
    KTH, School of Electrical Engineering (EES).
    On the security of VoIP mobile network operator and international carrier interconnects2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    All Mobile Network Operators (MNOs) as well as international carriers are moving voice services from the legacy Public Switched Telephone Network (PSTN) to Voice over IP (VoIP). The benefit is that VoIP traffic can be easily rerouted at any moment, thus giving companies a variety of options as traffic can be rerouted to any carrier of choice leading to different Quality of Service (QoS) levels (and thus agreements) as well as different prices to choose from. With a fierce competition for the telecom companies involved in the voice traffic hubbing business, this new landscape offers not only opportunities but also opens the system to vulnerabilities. The stakes are actually quite high: If harm can be done to one of these international carriers, other companies will route away their traffic. The result will be significant financial damages for the company as well as a serious harm to its reputation. The aim of this paper is to raise awareness that internationalcarriers and in particular their VoIP traffic can be exposed to debilitating attacks to harm these systems that are critical for our everyday life. The experimentation in this project demonstrates with a hands-on example how a major carrier can be hacked and rendered useless. In particular, we craft a framework for testing the security of interconnects between MNOs and international carriers. The central point of the paper will be to demonstrate how easy it can be to attack major carriers in the market: using common open source tools without having any information in advance. Moreover, the goal is to understand how the market functions, how interconnects between companies are built, where the weaknesses are, and which solutions can thwart those threats and secure these systems.

  • 41.
    Nguyen, Minh Duc
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Application-aware Scheduling in Multichannel Wireless Networks with Power Control2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Scheduling algorithm is the algorithm to allocate system resources among processes and data flows. Joint channel-assignment and workload-based (CAWS) is a recently developed algorithm for scheduling in the downlink of multi-channel wireless systems, such as OFDM. Compared to well known algorithms, CAWS algorithm has been proved to throughput optimal with flow-level dynamics.

    In this master thesis project, we design a system that accounts for power control and for the characteristics of common radio channels. We evaluate the efficiency of the algorithm under a diverse set of conditions. We also do analysis of CAWS algorithm under different traffic density.

  • 42.
    Panopoulos, Vasileios
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Near Real-time Detection of Masquerade attacks in Web applications: catching imposters using their browsing behavor2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This Thesis details the research on Machine Learning techniques that are central in performing Anomaly and Masquerade attack detection. The main focus is put on Web Applications because of their immense popularity and ubiquity. This popularity has led to an increase in attacks, making them the most targeted entry point to violate a system. Specifically, a group of attacks that range from identity theft using social engineering to cross site scripting attacks, aim at exploiting and masquerading users. Masquerading attacks are even harder to detect due to their resemblance with normal sessions, thus posing an additional burden.

    Concerning prevention, the diversity and complexity of those systems makes it harder to define reliable protection mechanisms. Additionally, new and emerging attack patterns make manually configured and Signature based systems less effective with the need to continuously update them with new rules and signatures. This leads to a situation where they eventually become obsolete if left unmanaged. Finally the huge amount of traffic makes manual inspection of attacks and False alarms an impossible task. To tackle those issues, Anomaly Detection systems are proposed using powerful and proven Machine Learning algorithms.

    Gravitating around the context of Anomaly Detection and Machine Learning, this Thesis initially defines several basic definitions such as user behavior, normality and normal and anomalous behavior. Those definitions aim at setting the context in which the proposed method is targeted and at defining the theoretical premises. To ease the transition into the implementation phase, the underlying methodology is also explained in detail.

    Naturally, the implementation is also presented, where, starting from server logs, a method is described on how to pre-process the data into a form suitable for classification. This preprocessing phase was constructed from several statistical analyses and normalization methods (Univariate Selection, ANOVA) to clear and transform the given logs and perform feature selection. Furthermore, given that the proposed detection method is based on the source and1request URLs, a method of aggregation is proposed to limit the user privacy and classifier over-fitting issues. Subsequently, two popular classification algorithms (Multinomial Naive Bayes and Support Vector Machines) have been tested and compared to define which one performs better in our given situations.

    Each of the implementation steps (pre-processing and classification) requires a number of different parameters to be set and thus a method called Hyper-parameter optimization is defined. This method searches for the parameters that improve the classification results. Moreover, the training and testing methodology is also outlined alongside the experimental setup. The Hyper-parameter optimization and the training phases are the most computationally intensive steps, especially given a large number of samples/users. To overcome this obstacle, a scaling methodology is also defined and evaluated to demonstrate its ability to handle larger data sets.

    To complete this framework, several other options have been also evaluated and compared to each other to challenge the method and implementation decisions. An example of this, is the "Transitions-vs-Pages" dilemma, the block restriction effect, the DR usefulness and the classification parameters optimization. Moreover, a Survivability Analysis is performed to demonstrate how the produced alarms could be correlated affecting the resulting detection rates and interval times.

    The implementation of the proposed detection method and outlined experimental setup lead to interesting results. Even so, the data-set that has been used to produce this evaluation is also provided online to promote further investigation and research on this field.

  • 43.
    Petrov, Svetlomir
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Patch Delivery Infrastructure in SCADA Systems2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    As other technologies, the SCADA architecture, whose origin can be traced back to midtwentiethcentury, was not designed initially with security in mind. Recent cyber-attacks andsecurity incidents show that approaches like security through obscurity and air-gapping thesystems are not relevant anymore. An analysis from E-ISAC about the cyber-attack on theUkrainian power grid shows that the risk could be significantly mitigated with prioritizing andpatching the known vulnerabilities on the most critical assets in an organization. The problem ishow to assure the secure deployment of patches in a timely manner and to ensure that they areapplied to the correct targets. This is achievable with a patch delivery infrastructure.Within a heterogeneous environment with several operating system platforms, multiple use casesand stringent security requirements there is no standardized design which solves the problem.This was the case in large SCADA manufacturer who provides patch management service to itscustomers around the globe. The goal of the degree project was to study and model its currentpatch management workflow, the current patch delivery infrastructure and propose new designsand approaches based on the collected use cases, that must be covered by the company, andrequirements from academia and industry standards. Two new concrete designs were proposedwith different level requirements fulfilment and changes which must be done compared to the asisstate in the company. They are based on client-server and configuration manager approaches.A third multi-platform configuration management solution is briefly outlined and will require acomplete change in the patch delivery infrastructure.Lastly, an evaluation framework was applied on the current patch delivery infrastructure and thetwo concrete design proposals which ranks them according to the fulfilment of the collected usecases and requirements. One should note that the best solution which solves the problem mightnot be the best solution to be implemented in the company. Future work will be needed to makeprototypes, test and evaluate them with a better framework developed by the enterprise’s experts.

  • 44.
    KTH, School of Electrical Engineering (EES), Communication Theory.
    Implementing Distributed Storage Systemsby Network Coding and ConsideringComplexity of Decoding2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Recently, network coding for distributed storage system has become a popular field due to increasing applications such as video, VoIP or mail. There are lots of theoretical works in this field, yet not enough practical study. In this thesis we implement a distributed storage system using network coding. In our implementation, three strategies of coding applied to this system: replication, regenerating code and regenerating code with repair by transfer. To study advantageous or disadvantageous of these strategies, we measure probability of successful downloading, repair time and processing time after implementation. We further study regenerating code with different finite field. Moreover we propose a method for low complexity of decoding algorithm. It is to assign different number of connected storage node which a receiver uses to reconstruct an original file. Our results show that the regenerating code with repair by transfer is an optimal network code for the distributed storage system when comparing to other strategies when working in small finite field size. In particular, in GF(2), the code only uses exclusive-OR to encode and decode data. In addition when finite field is large, the probability of successful downloading increases with the cost of higher complexity comparing to network code with small finite field size. To work in small finite field and consequently reducing complexity in decoding, we show by increasing number of connected node the probability of successful downloading improves. Thus we conclude that the regenerating code with repair by transfer is optimal implementation within system. However if we only consider the regenerating code with different number of connected storage node retrieving the original file, higher number of connected storage node is better than lower number of storage node connected.

  • 45.
    Rathinam Karthikeyan, Siddharth
    KTH, School of Information