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  • 201.
    Eriksson, Viktor
    Linköpings universitet, Institutionen för systemteknik, Kommunikationssystem. Linköpings universitet, Tekniska högskolan.
    Extraction of radio frequency quality metric from digital video broadcast streams by cable using software defined radio2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The purpose of this master thesis was to investigate how effiecient the extractionof radiofrequency quality metrics from digital video broadcast (DVB) streamscan become using software defined radio. Software defined radio (SDR) is a fairlynew technology that offers you the possibility of very flexible receivers and transmitters where it is possible to upgrade the modulation and demodulation overtime.

    Agama is interested in SDR for use in the Agama Analyzer, a widely deployedmonitoring probe running on top of standard services. Using SDR, Agama coulduse that in all deployments, such as DVB by cable/terrestrial/satellite (DVBC/T/S), which would simplify logistics.

    This thesis is an implementation of a SDR to be able to receive DVB-C. TheSDR must perform a number of adaptive algorithms in order to prevent the received symbols from being significantly different from the transmitted ones. Themain parts of the SDR include timing recovery, carrier recovery and equalization.Timing recovery performs synchronization between the transmitted and receivedsymbols and the carrier recovery performs synchronization between the carrierwave of the transmitter and the local oscillator in the receiver. The thesis discusses various methods to perform the different types of synchronizations andequalizations in order to find the most suitable methods.

  • 202.
    Ernmark, Niklas
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Data- och elektroteknik.
    Utveckling av en CAN-adapter i ett sensorsystem för övervakning av däcktryck.: Development of a CAN-adapter in a sensor system for tire pressure monitoring.2017Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Den här rapporten beskriver ett examensarbete i elektroteknik på Kungliga tekniska högskolan. Syftet var att skapa en unik systemlösning där ett CAN-adapterkort (Controller Area Network) skulle integreras med ett system för övervakning av däcktryck i tunga fordon. Målet var att presentera mätvärden från ventilsensorer på en persondator. Systemet för övervakning av lufttryck heter J1939 – TPMS och är en färdig produkt. J1939 – TPMS skickar CAN-ramar på en CAN-buss i J1939-format. Dessa ramar ska läsas in av adapterkortet och presenteras på ett terminalprogram på en persondator. Arbetet har bestått av att utreda hur systemet J1939 – TPMS fungerar i detalj. Rollen för protokollet J1939 och dess förhållande till CAN har förklarats. Hur J1939-ramar tolkas och hur mätdata rörande TPMS avkodas har beskrivits i detalj. Principer för hur en CAN-nod fungerar har klargjorts. Baserat på detta har ett CAN-adapterkort konstruerats. Konstruktionen har inneburit komponentval, design av elektronikschema, design av mönsterkort och utveckling av inbyggd programvara. Resultatet blev ett färdigt och fungerande CAN-adapterkort som har testats med J1939 – TPMS. Kraven för projektet uppfylldes. Dock så kommer mer arbete med kortet och systemet behövas för att det ska bli en färdig produkt. Arbetet genomfördes hos Motion Control i Västerås AB i samarbete med Transeco Däckservice.

  • 203.
    Ervenius, Johan
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Tysk, Filip
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Dual-mode Capability in a WLAN-equipped PC for Roaming and Mobility between WLANs and GPRS Networks2001Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The goal of this masters thesis work has been to develop and evaluate a solution that enables a WLAN-equipped mobile PC to establish and maintain connectivity by means of cellular network services, and more specifically a GPRS network, when roaming and moving outside the coverage area of a WLAN.

    Both network operators and the software industry are looking for inter-technology roaming solutions that can be implemented with minimal changes to existing infrastructures and standards. We have come to the conclusion that the use of Mobile IP is the solution that best meets these conditions as it is implemented on an IP level and treats wireless LAN and GPRS as peer networks, without any modifications to WLAN or GPRS protocols.

    In addition to the architectural solution efficient mobility is also dependent on the choice of handover algorithm, which decides when to connect to the WLAN and when to connect to the GPRS network. Using studies and measurements we have concluded that a good handover algorithm is vital for good TCP performance when performing a handover between WLAN and GPRS.

  • 204.
    Eslami, Mohammad Zarifi
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    A Presence Server for Context-aware Applications2007Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This master’s thesis project “A Presence Server for Context-aware Applications” was carried out at KTH Center for Wireless Systems (Wireless@KTH). The overall goal of this thesis project is to implement a context aware infrastructure to serve as middleware for different kinds of context aware applications, such as a context-aware printing application, location based notifier application, etc. This thesis examines different types of context aware architectures and considers different forms of context modeling. Additionally the thesis also explores some of the related technology, in order to provide the reader with suitable background information to understand the rest of the thesis. By using the SIP Express Router (SER) and its presence module (pa) a context server has been designed, implemented, and evaluated. Evaluation reveals that the critical bottleneck is the increasing service time as the number of Publish messages for different events in the SER database increases, i.e. the time required for handling and sending the Notify messages when a new Publish message is received increases as a function of the number of earlier Publish messages. The evaluation also shows that the dependence of SER upon the MySQL database as incorrect database queries can cause SER to crash. Additionally the performance of the database limits the performance of the context server. A number of future improvements are necessary to address security issues (in particular the authentication of Watchers) and adding policy based control in order to send Notify messages only to the Watchers authorized to receive information for a specific event.

  • 205.
    Esmael, Muzeyen Hassen
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Modeling Basic Physical Links in Acumen2012Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Simulation is the process of computing a behavior determined by a given model of a system of interest.  Modeling is the process of creating a model that formally describes a given class of system.  Modeling and simulation can be used to quickly and cheaply study and understand new technologies.  Today, a wide range of systems are simulated using different tools.  However, converting models into simulation codes can still be difficult and time consuming.

    In this thesis, we study how a new modeling and simulation language called Acumen can be used to model basic physical links.  This language is aimed at bridging the gap between modeling and simulation.  We focus on basic physical links as an interesting type of system to model and simulate. We also focus on comparing Acumen to MATLAB and Simulink.  The types of links we consider include models of an RC low-pass filter, Amplitude Modulation, Frequency Modulation, Amplitude Shift Keying, Phase Shift Keying and Frequency Shift Keying systems. Each of these examples is modeled in Acumen, MATLAB and Simulink. We find that, for the most part, Acumen allows us to naturally express a wide range of modulation techniques mentioned above. When compared to MATLAB ad Simulink, we find that Acumen is simple language to understand. Acumen codes are described in a more natural way. Simplicity is the biggest advantage of Acumen.

  • 206.
    Evripidis, Romanidis
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Lawful Interception and Countermeasures: In the era of Internet Telephony2008Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Lawful interception and the way it is performed have played a significant role in the effectiveness of this type of communication monitoring. Although the secrecy of interception and the related equipment are supposed to provide correct information to a law enforcement agency, there are some countermeasures that can be taken by the subject that can seriously undermine the collection of correct and accurate data.

    This thesis project attempts to identify the problems that exist for interception of telephony (be it fixed, mobile, or via the Internet). Moreover, there are some suggestions for improvements how lawful interception should be performed in order to avoid possible attacks that could decrease the credibility of the intercepted data. Numerous publications (in print or distributed on the Internet) have described weaknesses in the current state of the art lawful interception when using equipment that can be purchased in the market. This thesis presents improvements in how LI can be conducted in order to avoid these vulnerabilities. Additionally, there is a description of the key escrow systems and the possibility of avoiding one of their most significant vulnerabilities.

    The main problem of the lawful interception is the rapid changes in telecommunications and the complicated architecture of the telecommunication networks, as both make monitoring vulnerable to specific countermeasures. An analysis of how lawful interception can take place and current countermeasures for lawful interception of Internet telephony are vital in order to identify the problems in carrying out such intercepts today and to make suggestions for improvements.

    This topic is especially relevant given the current Swedish “FRA lagen” regarding interception of electronic communication going into, out of, and through Sweden. Not only is it important to understand how lawful interception can be performed or prevented, but it is also important to understand how information obtained from lawful interception could be purposely misleading or falsified.

  • 207.
    Fahad Azeemi, Muhammad
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    HydraNetSim: A Parallel Discrete Event Simulator2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Discrete event simulation is the most suitable type of simulation for analyzing a complex system where changes happen at discrete time instants. Discrete event simulation is a major experimental methodology in several scientific and engineering domains. Unfortunately, a conventional discrete event simulator cannot meet with increasing demands of computational or the structural complexities of modern systems such as peer-to-peer (P2P) systems; therefore parallel discrete event simulation has been a focus of researchers for several decades.

    Unfortunately, no simulator is regarded as a standard which can satisfy the demands of all kinds of applications. Thus while given a simulator yields good performance for a specific kind of applications, it may failed to be efficient for other kinds of applications. Furthermore, although technological advancements have been made in the multi-core computing hardware, none of the mainstream P2P discrete event simulators is designed to support parallel simulation that exploits multi-core architectures. The proposed HydraNetSim parallel discrete event simulator (PDES) is a step toward addressing these issues. Developing a simulator which can support very large numbers of nodes to realize a massive P2P system, and can also execute in parallel is a non-trivial task. The literature review in this thesis gives a broad overview of prevailing approaches to dealing with the tricky problems of simulating a massive, large, and rapidly changing system, and provides a foundation for adopting a suitable architecture for developing a PDES.

    HydraNetSim is a discrete event simulator which allows parallel simulation and exploits the capabilities of parallelization of modern computing hardware. It is based on a novel master/slave paradigm. It divides the simulation model into a number of specific slaves (a cluster of processes) considering the number of cores provided by the underlying computing hardware. Each slave can be assigned to a specific CPU on a different core. Synchronization of the slaves is achieved by proposing a variant of the classic Null-Message Algorithm (NMA) with a focus on keeping the synchronization overhead as low as possible. Furthermore, HydraNetSim provides log information for debugging purposes and introduces a new mechanism of gathering and writing simulation results to a database.

    The experimental results show that the sequential counterpart of HydraNetSim (SDES) takes 41.6% more time than HydraNetSim-2Slave and 23.6% than HydraNetSim-3Slave. HydraNetSim-2Slave is 1.42 times faster, consumes 1.18 times more memory, and supports 2.02 times more nodes than a sequential discrete event simulator (SDES). Whereas, HydraNetSim-3Slave executes 1.24 times faster, consumes 2.08 times more memory, and supports 3.04 times more nodes than SDES. The scaling factor of HydraNetSim is ⌈(β-1)*102.04%⌉ of the maximum numbered of nodes supported by SDES; where β is the number of slaves.

  • 208.
    Falgert, Marcus
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Geo-distributed application deployment assistance based on past routing information2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Cloud computing platforms allow users to deploy geographically distributed applications on servers around the world. Applications may be simple to deploy on these platforms, but it is up to the user and the application to decide which regions and servers to use for application placement. Furthermore, network conditions and routing between the geo-distributed servers change over time, which can lead to sub-optimal performance of applications deployed on such servers.

    A user could either employ a static deployment configuration of servers, or attempt to use a more dynamic configuration. However, both have inherent limitations. A static configuration will be sub-optimal, as it will be unable to adapt to changing network conditions. A more dynamic approach where an application could switch over or transition to a more suitable server could be beneficial, but this can be very complex in practice. Furthermore, such a solution is more about adapting to change as it happens, and not beforehand.

    This thesis will investigate the possibility of forecasting impending routing changes between servers, by leveraging messages generated by the Border Gateway Protocol (BGP) and past knowledge about routing changes. BGP routers can delay BGP updates due to factors such as the minimum route advertisement interval (MRAI). Thus, out proposed solution involves forwarding BGP updates downstream in the network, before BGP routers process them. As routing between servers changes, so does the latency, meaning that the latency then could be predicted to some degree. This observation could be applied to realize when the latency to a server increases or decreases past another server. This in turn facilitates the decision process of selecting the most optimal servers in terms of latency for application deployment.

    The solution presented in this thesis can successfully predict routing changes between end-points in an enclosed environment, and inform users ahead of time that the latency is about to change. The time gained by such predictions depend on factors such as the number of ASs between the end-points, the MRAI, and the update processing delay imposed on BGP routers. Time gains between tens of milliseconds to over 2 minutes has been observed.

  • 209.
    Falk Drugge, Anna Elisabet
    KTH, Tidigare Institutioner, Teleinformatik.
    User Centered Communicating Devices1997Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    The extensive use of communicating computers in the future will require the development of products and services that are easy to use. With this in mind a literature study has been done. The report presents examples of current and some visions of future human centered communication devices. They are described from three different aspects: human, societal, and technical.

    In the section on the human aspect three different classes of interfaces are described: unnoticeable, intuitive, and social. The intention with the section on the societal aspect is to give examples of how different social institutions will change and the new possibilities those changes will bring. In the technology section new development and research are presented in the areas of input/output devises, networks, and power supply.

    The intention with this report is not to cover all possibilities or to present solutions, instead the aim is to serve as a source of inspiration and provide food for thought.

  • 210.
    Falk, Mikael
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Fernandez Karlsson, Matias
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Driftövervakning av Windows och Linux/Unix Servrar2008Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Ju fler servrar, med olika konfigurationer och olika system, som blir medlemmar i ett nätverk, desto svårare och osmidigare blir det att övervaka nätverksmiljön. Men om man använder sig av ett övervakningssystem, som tar emot information från flera servrar, blir det lättare att få en överblick om hur allt fungerar och samtidigt som det går snabbare att få information om felmeddelanden, som man sedan kan åtgärda.

    I detta dokument tar vi upp olika typer av övervakningssystem som finns ute på marknaden idag, våren 2008. Bland dessa hittar vi t.ex. SCOM 2007, BigBrother, Nagios och Mon. Vi har inte begränsat oss till ett specifikt operativsystem, utan vi tar upp övervakningssystem som passar till Windows och/eller Linux/Unix.

    Utifrån den information vi hittat om varje övervakningssystem och de kriterier som Valderas Consulting AB vill att systemen ska uppfylla, har vi valt ut tre stycken övervakningssystem som vi tycker passar bäst. Dessa system har vi sen, ett och ett, testat i ett litet nätverk där vi utsätter det för en del scenarior som kan hända ute på företag som t.ex. trasig anslutning, för full hårddisk och kraschat operativsystem.

    De tre övervakningssystem vi tyckte höjde sig över mängden var SCOM 2007, Big Brother 4 och Nagios. Efter att ha testat vart och ett av dessa tre tycker vi att Nagios är det klart bästa. Det är användarvänligt i installationen, konfigurationen samt i övervakningen. En annan stor fördel med Nagios är att det är gratis, dvs. open source. Om ens datormiljö enbart innehåller Windows-datorer och en domän, passar SCOM 2007 bäst, då Nagios måste installeras på en Linux/Unix-dator. Big Brother 4 var bra det med, men faller bort pga. att det inte är gratis, färre testmöjligheter på nätverket och fungerade inte helt bra med att övervaka Linux/Unixdatorer.

  • 211.
    Fatollahy, Masoud
    KTH, Tidigare Institutioner, Teleinformatik.
    ISP Selectivity Using NAT1998Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This document describes Network Address Tra nslation and investigates the possibilities of using NAT on an Edge Rouer to provide ISP slectivity for the users, and describes an implementation of NAT on Ericssson's AX51x Edge Router. The reasons for allowing users to slect their ISP are that, customers may change providers, customers may utilize different ISPs for different services, company backbones may be reorganized, or providers may merge or split. This document also briefly describes other areas that are relevant to this task.

  • 212.
    Fawzy Kamel, Menatalla Ashraf
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Vendor Lock-in in the transistion to a Cloud Computing platform2015Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The thesis introduces a study about the vulnerabilities that a company as Scania IT faces towards vendor lock-in in the transition to a cloud computing platform. Cloud computing is a term that refers to anetwork of remote servers hosted on the internet to store, manage and process data, rather than on a local server or a personal computer. Vendor lock-in is an outcome that causes companies to pay a significant cost to move between cloud providers. The effects that cause vendor lock-in that will be described are portability, interoperability and federation are called the lock-in effects. The goal of the research is to help Scania IT understand the vendor lock-in and the vulnerabilities they can face in the transition to the cloud as well as to clarify the concern that they may have against falling in vendor lock-in. The main purpose of the research is to present the various lock-in effects that are related to the transition from one cloud provider to another and the vulnerabilities that cause companies to fall in vendor lock-in. The thesis presents the reasons that motivates why Scania IT would consider using the cloud and the concerns that they may have against usage of a cloud computing platform. The results will be based on a case study of a similar company that has moved to a cloud provider and specifically Microsoft Azure and an interview of Microsoft Azure point of view with the risk of vendor lock-in. Finally, a process of interviews with different people from Scania IT to extract the current bottleneck in the development process that caused the company to think of a cloud computing platform. The results show that companies should consider many risks and factors while moving to the cloud, as vendor lock-in, cloud maturity index and their IT strategies. As a result, the thesis gives recommendations of the steps needed to minimize the risks of the cloud while maintaining the positivity of the cloud.

  • 213.
    Faxén, Linnea
    Linköpings universitet, Institutionen för systemteknik, Kommunikationssystem.
    A Study on Segmentation for Ultra-Reliable Low-Latency Communications2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    To enable wireless control of factories, such that sensor measurements can be sent wirelessly to an actuator, the probability to receive data correctly must be very high and the time it takes to the deliver the data from the sensor to the actuator must be very low. Earlier, these requirements have only been met by cables, but in the fifth generation mobile network this is one of the imagined use cases and work is undergoing to create a system capable of wireless control of factories. One of the problems in this scenario is when all data in a packet cannot be sent in one transmission while ensuring the very high probability of reception of the transmission. This thesis studies this problem in detail by proposing methods to cope with the problem and evaluating these methods in a simulator. The thesis shows that splitting the data into multiple segments and transmitting each at an even higher probability of reception is a good candidate, especially when there is time for a retransmission. When there is only one transmission available, a better candidate is to send the same packet twice. Even if the first packet cannot achieve the very high probability of reception, the combination of the first and second packet might be able to.

  • 214.
    Faxér, Sebastian
    Linköpings universitet, Institutionen för systemteknik, Kommunikationssystem. Linköpings universitet, Tekniska högskolan.
    Self-optimization of Antenna Sectorization2014Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Sectorization is a well-established method of increasing the capacity of telecommunicationnetworks. With modern Active Antenna Systems (AAS) comes the abilityto change sectorization order dynamically, both in horizontal and vertical plane.The purpose of this thesis is to investigate when (and what type of) sectorizationis benficial. A theoretical analysis as well as simulations are performed in orderto determine which quantities to look at when making the decision to apply sectorization.Based on the conclusions from these investigations, a self-optimizingalgorithm that only turns on sectorization when it increases network performanceis developed and evaluated. It is shown that large gains can be achieved by onlyturning on sectorization when the right conditions are met. Further, we show thatadditional gains can be seen if antenna parameters such as downtilt and distributionof transmission power between sectors are set properly. Self-optimizingalgorithms for tuning of these parameters are developed and evaluated as well.NyckelordKeywords

  • 215.
    Feng, Xuan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Evaluation of Capuchin Application Programming Interface: Implementing a Mobile TV Client2009Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The purpose of this research was to evaluate the Capuchin API launched by Sony Ericsson at Lund, Sweden in 2008. The Capuchin API bridges Adobe’s Flash graphics and effects with JSR support from Java ME. We evaluated Capuchin API with regard to its suitability for a Mobile TV application. We tested this API in Ericsson’s TV lab where we had access to live TV streams and online multimedia resources by implementing a Mobile TV client. This test application was named “Min TV”, in English: “My TV”.

    Using Capuchin in the Ericsson TV lab environment has shown that it has some benefits, but also has many drawbacks. The Flash developer can be used to create an animated user interface and Java developers can do complex programming. At this early stage Capuchin technology is not mature enough, nor is it suitable for Mobile TV client development. Only after Sony Ericsson adds features such as soft keys, easier debugging of Flash Lite standalone applications, test emulator support in the software development kit, and more data communication methods than string and number, only then it will be a suitable technology for Mobile TV applications.

    Ericsson’s current Mobile TV application client was built using a framework called ECAF, which supports a graphics frontend and Java ME as backend. We compared ECAF and Min TV with respect to parameters such as: flexibility, performance, memory footprint, code size, and cost of skinning. (All these parameters are explained in detail in the methodology chapter.)

    As a possible future technology for Mobile TV, we evaluated a number of different presentation/graphics technologies including HECL, SVG Tiny, MIDP 3.0, .NET Compact Framework, etc. Moreover, we examed if a pure Flash Lite client application is a viable solution for Mobile TV. The comparison of different presentation technologies showed that Java ME is a comprehensive platform for mobile development offering all the necessary support from third party graphical user interface makers. .NET CF also looks like a good option for development with the scaled down capabilities for different programming languages supported using CLR.

  • 216.
    Fernández, Alexis Martínez
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Authorization schema for electronic health-care records: For Uganda2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This master’s thesis project began at the Karolinska University Hospital. This thesis discusses how to design an authorization schema focused on ensuring each patient’s data privacy within a hospital information system. It begins with an overview of the current problem, followed by a review of related work. The overall project’s goal is to create and evaluate an authorization schema that can ensure each patient’s data confidentiality.

    Authorization has currently become a very important aspect in information systems, to the point of being a necessity when implementing a complete system for managing access control in certain complex environments. This requirement lead to the approach that this master thesis takes for effectively reasoning about authorization requests in situations where a great number of parameters could affect the access control assessment.

    This study is part of the ICT4MPOWER project developed in Sweden by both public and private organizations with the objective of improving health-care aid in Uganda through the use of information and communication technologies.  More concretely, this work defines an authorization schema that can cope with the increasing needs of sophisticated access control methods where a complex environment exists and policies require certain flexibility.

  • 217.
    Fey, Enikö
    KTH, Tidigare Institutioner, Teleinformatik.
    The Effect of Combining Network and Server QoS Parameters on End-to-End Performance2000Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Application hosting is becoming a popular business, Application Service Providers (ASPs) need however to keep up with the increasing pace of the market. This implies that they have to provide infrastructure to an increasing number of clients, and at the same time give QoS guarantees to these clients. One solution for ASPs to both guarantee a certain service level (QoS) for their clients and keep expanding would be to have so many resources as to be able to provide more than the maximum aggregate need of their clients. This may turn out to be an expensive or even an impossible solution - sharing infrastructure between clients and offering some means of resource reservation, and using charging to insure that clients only reserve the resources they need, is an alternative.

    It is however not an easy problem to solve, particularly if the procedure of adding new clients is to be automated, and the resources dynamically allocated. The ICorpMaker framework being developed at the IBM Zurich Research Laboratory offers a solution to the above named problems. In the ICorpMaker framework dynamic resource allocation is achieved by letting clients modify the amount of resources allocated to them in a simple manner, requesting more or less resources than their current allotment.

    The difficulty in achieving the end-to-end performance the client desires, lies in the fact that it is not certain how modifying resource allocation at the network respectively server level will combine and affect the end-to-end performance experienced by the end users of the service. The aim of this thesis project was to study the correlation between different network and server QoS parameters and the resulting end-to-end performance by making measurements. The results obtained from these measurements give an answer to the question of how to change the network and server resource allocations, when a client's application does not perform in a satisfactory way and hence the client requests more resources. Certain optimizations for the resource (re)allocation were also suggested based on the results.

  • 218.
    Fey, Zsuzsa
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Adapting and Optimising TCP/IP on Satellite Networks2001Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Today communication has become an essential part of our lives. As communication becomes even more global, one has to search for new communication forms, which can satisfy the new needs of the customers. One emerging area is communication via satellites. As the TCP/IP protocol family is the most used protocol family in today's Internet, but was developed primarily for communication on wired links, it has suboptimal behaviour when used with satellite links.

    The purpose of this master's thesis is to examine the shortcomings of using the TCP/IP protocol suite on satellite links, to see what types of problems occur in satellite communication, how these problems affect TCP/IP and to try to find solutions to the problems found.

    The thesis begins with a presentation of the TCP/IP protocols and the issues regarding satellite communications, more precisely the DVB-RCS standard. Then we will take a look at existing improvements for TCP/IP communication over satellite links. The main part of the thesis is to study the behaviour of the different implementations of the TCP/IP protocolson satellite links and to examine possible improvements.

    Finally there are presented the conclusions drawn. The experiments showed that better performance is achieved for initial congestion window sizes of 3 or 4. It was also seen a performance discontinuity at return channel bandwidth of 512 kbps. At low BER TCP Reno performed best, while at high BER no general behaviour was seen. However, at high BER TCP SACK or TCP FACK performed best in most of the studied cases.

  • 219.
    Filimonovic, Martin
    KTH, Tidigare Institutioner, Teleinformatik.
    Voice over IP - SIP client1999Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    The interest in utilizing the Internet for real-time communication has grown substantially in recent years. This thesis covers the features of Voice over IP and IP telephony and the signaling protocols used for establishing and terminating calls over the Internet

    Two signaling protocols will be compared, SIP from IETF and H.323 from ITU. A deeper investigation of SIP was made, with the purpose of making a small implementation of a SIP client for point to point communication. Two different approaches were developed. The report will also outline the comparisment of SIP and H.323 and the evaluation of the SIP user agents.

  • 220.
    Folke, Fredrik
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Security for home, small & medium sized enterprises IPv6 networks: Security using simple network equipment2012Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    This theses project investigates and presents different threats that a network can be exposed to and the common protection techniques that can be applied, with a focus on the network perimeter – specifically the router/firewall between the local area network and the Internet. All Internet connected devices and networks are exposed to and affected by security threats to some degree, hence security is important in almost every type of network. With the constant growth of the Internet the 32-bit addressing scheme ipv4 is proving to be inadequate, and therefore the transition to the 128-bit addressing scheme ipv6 is becoming critical. With ipv6 comes new security threats (while still old threats remain) that requires an understanding of perimeter security. In this thesis we secure a home router and describe these steps to enable home and small business owners to secure their IPv6 network at a relatively low cost.

  • 221.
    Forsberg, Joakim
    KTH, Tidigare Institutioner, Teleinformatik.
    HTTP in a Realtime OS1999Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Web servers are today found in devices that no one could imagine a couple of years ago. At that time people asked themselves who would use a Web server at all. Today the questions is why would anyone put a Web server in an embedded device? But that is actually what is happening right now. Today te industry is trying to webify virtually everything from banking errands to our homes. This developmnet has lead to the fact Hypertext Transfer Protocol (HTTP) servers, ofen referred to as a Web server, are found in almost all the devices that can be hooked to a network. Therefore it is quite natural to study f a Web server could be used in an embedded systems link AXE 10. The real question is probably: Is it feasible to have a server in the operating system EriOS? The answer is that a Web server can be used, but it might be better to use a SNMP server in the AXE10 and a Web server outside the AXE10. In this case SNMP would be used to query the AXE10. EriOS is an operating system that is written in the language EriPascal.

  • 222.
    Forsell, Erik
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Internet Telephony: An Internet Service Provider's Perspective2005Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The aim of this Masters Thesis is to propose to SYSteam Nät AB, a local Internet Service Provider (ISP) in Uppsala, Sweden, how to implement IP telephony in their existing ITinfrastructure as a service to their customers. Thus the perspective of the thesis will be that of a local Internet Service Provider. Three general areas are covered in the thesis: Market and Business Model, Technology, and Economics.

    Important issues for SYSteam Nät AB as an established local broadband Internet Service Provider are to both retain present customers and to attract new customers. Some believe that offering value added services such as IP telephony could do this.

    Implementation of IP telephony can be done in different ways to fulfil SYSteam Nät’s requirements. The analysis leads to a proposal of how SYSteam Nät could implement IP telephony. This involves many multi-faceted business, technical, and financial issues; each aspect is examined in this thesis.

  • 223.
    Forte, Paolo
    KTH, Skolan för elektro- och systemteknik (EES), Kommunikationsnät.
    Predicting Service Metrics from Device and Network Statistics2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    For an IT company that provides a service over the Internet like Facebook or Spotify, it is very important to provide a high quality of service; however, predicting the quality of service is generally a hard task. The goal of this thesis is to investigate whether an approach that makes use of statistical learning to predict the quality of service can obtain accurate predictions for a Voldemort key-value store [1] in presence of dynamic load patterns and network statistics. The approach follows the idea that the service-level metrics associated with the quality of service can be estimated from serverside statistical observations, like device and network statistics. The advantage of the approach analysed in this thesis is that it can virtually work with any kind of service, since it is based only on device and network statistics, which are unaware of the type of service provided.

    The approach is structured as follows. During the service operations, a large amount of device statistics from the Linux kernel of the operating system (e.g. cpu usage level, disk activity, interrupts rate) and some basic end-to-end network statistics (e.g. average round-trip-time, packet loss rate) are periodically collected on the service platform. At the same time,

    some service-level metrics (e.g. average reading time, average writing time, etc.) are collected on the client machine as indicators of the store’s quality of service. To emulate network statistics, such as dynamic delay and packet loss, all the traffic is redirected to flow through a network emulator. Then, different types of statistical learning methods, based on linear and tree-based regression algorithms, are applied to the data collections to obtain a learning model able to accurately predict the service-level metrics from the device and network statistics.

    The results, obtained for different traffic scenarios and configurations, show that the thesis’ approach can find learning models that can accurately predict the service-level metrics for a single-node store with error rates lower than 20% (NMAE), even in presence of network impairments.

  • 224.
    Franson, Johan
    KTH, Tidigare Institutioner, Teleinformatik.
    Personal Information Services: seen from an Agent perspective1997Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This report approaches information services in an agentoriented way. First the concept of an ”agent” is discussed anddefined. Then an information world model is build. This modeltries to focus on information content, services, and users. Withthis model and the agent concept as tools, services such as, e.g.,call screening, mailboxes, notification, news services, messagetranslation, coordination of a user’s terminals, etc. arediscussed. The goal of this report is to inspire the reader tothink in an agent oriented way, rather than stating some kind ofultimate solution.

  • 225.
    Fredén, Magnus
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Mobile Internet: Testing of Internet services2005Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In addition to the problems that may occur in the Internet, the people who test mobile internet services confront additional challenges due to the wireless environment. If something goes wrong, it is very problematic for a tester to determine exactly where the error occurred and the reason why it occurred. Is it the software in the telephone that does not work properly, is the GPRS link stable, is the core network of the Internet working as it should, or is there something wrong at the server? The staff at Sony Ericsson has major difficulties determining where the origin of a problem is. They often simply know that something is not working. The major effort is often to detect the source of the actual problem rather than solving it.

    The PlayNow service provided by Sony Ericsson will be used as a reference service in this master’s thesis project. The PlayNow service is currently used for distributing ring signals. It is built on Internet standards, but depends on GSM’s specific features both for distribution and for e-commerce which makes it hard to test using existing web test tools. This Master’s Thesis examines the difficulties in establishing robust IP traffic links between a server and a mobile telephone. It examines the entire communication path between the mobile telephone and the server, and focus on how to detect (potential) errors. Within this project, development of a test tool is included. It supports features necessary for testing the reference service PlayNow.

    This report covers many different technologies within the mobile internet such as GSM, GPRS, and mobile IP. Moreover, the normal infrastructure of the Internet will also be considered; as well as how the different parts interact in an environment consisting of a mobile Internet with GPRS. A major part of the project has been evaluation of the communication link between a mobile device and a server. Additionally, some efforts have focused on developing the new test tool.

  • 226.
    Frostensson, Tomas
    Linköpings universitet, Institutionen för systemteknik, Kommunikationssystem. Linköpings universitet, Tekniska högskolan.
    Hardware Implementation and Assessment of a Soft MIMO Detector Based On SUMIS2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    To allow faster and more reliable wireless communication a technique is to use multiple antennas in the transmitter and receiver. This technique is called MIMO. The usage of MIMO adds complexity to the receiver that must determine what the transmitter actually sent. This thesis focuses on hardware implementation suitable for an FPGA of a detection algorithm called SUMIS.

    A background to detection and SUMIS in particular is given as a theoretical aid for a better understanding of how an algorithm like this can be implemented. An introduction to hardware and digital design is also presented.

    A subset of the operations in the SUMIS algorithm such as matrix inversion and sum of logarithmic values are analyzed and suitable hardware architectures are presented. These operations are implemented in RTL hardware using VHDL targeted for an FPGA, Virtex-6 from Xilinx.

    The accuracy of the implemented operations is investigated showing promising results alongside of a presentation of the necessary resource usage.

    Finally other approaches to hardware implementation of detection algorithms are discussed and more suitable approaches for a future implementation of SUMIS are commented on. The key aspects are flexibility through software reprogrammability and area efficiency by designing a custom processor architecture. 

  • 227.
    Frostne, Isabel
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Traffic analysis of existing traffic in Kulyab region in order to plan and configure a new GSM MSC for this region2011Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Wide area cellular mobile networks have rapidly evolved over the years. In the beginning achieving wide area coverage was a great achievement – enabling subscribers to call from wherever they were currently located and whenever they wanted. Additionally these systems supported mobility of subscribers, so that calls could continue even while a subscriber moved from one cell to another. Today mobility management is something everyone takes for granted. New functionality is continuously being developed for these networks. An important aspect of this evolution has been to enable new applications and technologies to be introduced while maintaining interoperability with the existing technologies.

    These mobile networks use new technologies and enable new applications, but they interconnect with existing networks that utilize earlier technologies, such as the existing fixed telephone network. These interconnections enable communication between subscribers connected via all of these networks. In today’s mobile networks there are a variety of technologies working side by side, for example 2G, GPRS, 3G, and so on. The earlier networks used circuit switching technology, but the trend in later networks was to transition exclusively to packet switching.

    One of the most important network entities is the mobile switch center (MSC). In the earlier circuit switched networks the MSC is the heart of the circuit switching network. The MSC is responsible for management, control, and communication to and from the mobile stations (MSs) in the area managed by the MSC. The MSC stores information about each of the MSs in one or more databases. In the subscriber’s home network the information about their subscription is stored in a home location register (HLR), while when this subscriber is in another network information is stored in a visitor location register (VLR). The MSC together with other elements of the core network handles mobility management, enabling both handover and roaming. A gateway MSC enables MSs to communicate with phones connected to the fixed network.

    The aim of this thesis is to analyze the traffic situation for Kulyab region in order to configure and install the MSC in Kulyab. For the time being there is no radio network controller (RNC) in Kulyab region, so the MSC in Kulyab will be configured to support 2G traffic.

    The configuration will be based on the expected mobile traffic load in the Kulyab region, thus the first steps in the process were to collect and analyze data about the existing traffic in this region that is currently served by a MSC located outside of this region. The configuration of the new MSC will be based on this analysis.

    After installing and configuring the new MSC some question need to be answered, namely:

    1. Can the MSC in Kulyab support all the base stations in Kulyab region? If not, how many base stations can it support?
    2. To what extent does the addition of this new MSC improve the overall network in terms of increased reliability, capacity, and throughput?
    3. How much will the capacity of the existing MSC, that is responsible for traffic outside Dushanbe, be increased due to the introduction of the new MSC?
  • 228.
    Fu, Qiang
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Building models of Wireless Local Area Network coverage2007Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Wireless LANs are becoming more and more popular because they can provide high data rate network access to computer users without the tradition cable. Additionally mobile devices allow people to have connectivity, even when moving from place to place, additionally they are small in size and light in weight. While such devices only offer some of the capabilities of PC they are more convenient to use than a desktop PC when traveling. Cellular phone and smart phones have more function than before, with some newer models phone having an embedded GPS receiver. This GPS receiver can provide user with new services, in addition to location information. Many of these handheld devices include wireless LAN functionality, enabling people to walk from one place to another with a continuous network access, via either the WLAN or the cellular network. By using voice over IP, a wireless enabled hand device becomes a Virtual Cell Phone enabling low cost calls via the WLAN when the user is within coverage of an access point which will give them access, or via the normal cellular phone network (when with in coverage).

    Because the WLAN coverage is not ubiquitous, it is important to build a Wireless Network Coverage model to enable every user to see where there is WLAN network coverage. Present methods to create such a coverage map require a lot of work to collect data, both indoors and outdoors. Currently a lot of human effort is needed to collect, process, and format this data. The method proposed her could provide an easier way of gathering data from the field and be simple enough that even a normal user could collect data and contribute it to help generate a coverage model of areas where they visit.

    The measurements reported indicate that it is possible to combine data from multiple devices of the same and different types, but only when the signal strength is high. Fortunately, it is just these areas where the signal quality is good which are of interest to users. The thesis also shows one way of presenting this data in an easy to understand visual manner as an overlay on Google Earth.

  • 229.
    Fu, Yi
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Li, Ruimin
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    From Set Top Box to Home Media Center2014Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Although Set-top-Boxes(STBs) are widely deployed today to connect a media source to a display (traditionally a television set), the market is changing due to the introduction of Internet Protocol Television, Over-the-Top streaming devices, gaming console, home theater Personal Computer, smart TV, etc. There is an evolving concept of a Home Media Center (HMC). This HMC provides consumers with an integrated home media environment and experience.

    This thesis explores the transition from STBs to HMCs. The specific questions that this thesis project answers are: What will a future HMC look like? What will its functions be? What interfaces and protocols will it use? Who will make these HMCs?  How can STB vendors evolve to be HMC vendors or will they simply cease to exist?  This thesis project designed and evaluated a hypothetical HMC prototype based upon current technology trends and user expectations. This prototype was used with 68 volunteers to identify and prioritize the most important features that a HMC should provide. Based upon the most important of these features a conceptual HMC prototype is designed to define a HMC product roadmap for 1, 3, and 5 years. This roadmap is used to project the economic impact of HMCs on the current STB industry.  This economic analysis considers Sweden as the target market.

    This thesis could be used by current STB vendors to define their own company specific roadmaps to support their transition to the future HMC market.

  • 230.
    Fujita, Lie
    et al.
    KTH, Tidigare Institutioner, Teleinformatik.
    Körling (nee Beije), Madeleine
    KTH, Tidigare Institutioner, Teleinformatik.
    Internet Protocol Secirity1997Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    This paper gives an overview of the architecture and design of IPSec. IPSec is a network-layer security protocol for the IP protocol suite. The basic issues in authentication- and encryption techniques are presented as background material.

    We have installed and tested a freely available implementation of IPSec. Performance measurements were made using the tools Netperf-2.1 and DBS-1.1.4.

    We used high-performance personal computers and a high-speed network so that the results were determined only by the IPSec implementation. The performance loss was larger for the encryption algorithms than for the authentication algorithms.

    When using only authentication, the throughput was 37% of that without algorithm. With only encryption, the throughput was 15% and 7% for DES-MD5 and 3DES-MD5, respectively. When using both authentication and encryption on each packet, the throughput decreased to approximately 7,4% of that without algorithm.

  • 231.
    Färnlycke, Isak
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    An approach to automating mobile application testing on Symbian Smartphones: Functional testing through log file analysis of test cases developed from use cases2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Many developers today have difficulties testing their applications on mobile devices. This is due to a number of factors, such as the fact that the mobile phone market has become even more fragmented with the introduction of touch screen technology. Existing software that was designed for traditional mobile handhelds is not necessarily compatible with the newest models and vice versa. For developers this incompatibility increases the difficulty when creating software.

    Lack of resources for testing the application may lead to the application being limited to either just a specific model or in some cases to only one specific version of the operating system software. Without providing support for a large number of models the product may have difficulty attracting customers, and hence fail to gain the desired market share.

    The challenge is to find a way to make testing simple, effective, and automated on a large number of mobile devices. To achieve this test automation applicationsare needed and a test strategy must be devised. Additionally, testing is often described as never-ending since testing generally reveals errors rather than demonstrating when errors are absent. Because of this some limitations of testing are justified.

    In order to limit the scope of this thesis I have selected some of the most appropriate methods for testing, and will only examine these specific methods.  The focus for the testing is not specifically to find errors, but rather to confirm that the product offers the specified functionality.

    This thesis describes an approach to functional testing of an application for Symbian mobile devices based upon log analysis. Unfortunately, testing applications on mobile devices is still not straightforward, and this thesis does not shed any light upon how to lessen this complexity. However, I believe that both testing and development will be more and more built around use cases in the future. Unfortunately, automation of testing based uponthese use cases will be further complicated by the increasing use of touch screens and physical input (such as gestures).

  • 232.
    Gabdurahmanov, Murat
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Trygg, Simon
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Analysis and Evaluation of Network Management Solutions: A Comparison of Network Management Solutions Suitable for Networks with 2,500+ Devices2016Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [en]

    Some companies today are using sub-optimal and nearly obsolete management systems for their networks. Given the large number of different services that are demanded by users, there is a need to adapt the network structure to support the current and potential future demands. As a result, there is a need for new Network Management Solutions (NMSs).

    The aim of this thesis project is to help a company who uses a NMS called Local Area Network (LAN) Management Solution (LMS). LMS was designed by Cisco for managing LAN networks. However, the company’s demands are growing and they need to expand their network more than expected. Moreover, LMS is designed to only support devices by Cisco, whereas the company wants a universal solution with wide device support from many manufacturers.

    This thesis presents an analysis of their current system and suggests potential solutions for an upgrade that will meet all of the company’s demands and will have a long operating life. To help find reasonable solutions a thorough evaluation of their existing NMS and network monitoring and management needs was made.  This evaluation gave good insights into different aspects of their system. A reasonable solution was found by following a three-step approach, beginning with 82 possible solutions, filtering out and breaking down with each step, until only the most suitable NMS was left.

    Two NMSs has been proposed as equally suitable replacements: IBM Tivoli Netcool/OMNIbus and ManageEngine OpManager. Regardless of which one is chosen, they both have the following advantages over the company’s existing NMS: they are very stable solutions which can handle a large number of managed devices; they are universal solutions with wide device support, and the company can add custom support if needed; they are user-friendly with the ability to add custom interfaces; and they both have a professional first-line technical support department locally located.

  • 233.
    Gaitan, Ivar
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Real-time services and multihop networks: Delay analysis of a multihop CDMA fixed relay network2005Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The next generation of cellular networks is expected to carry high speed IP traffic in a packet switched environment in order to accommodate data traffic for a wide range of services. Much research is thus focused on how to increase the transmission rate in cellular networks. A general consequence of increasing transmission rate in a radio link is a corresponding increase in transmit power, resulting in increased interference and reduced network capacity. The straightforward way to reduce this effect is to shorten the link distance, which in the cellular case means shrinking the cells. This, however, means increased control traffic for handoffs and location registration, as well as increased infrastructure costs.

    An alternative approach, which has received increased attention lately, is the introduction of wireless multihop access networks to relay traffic between the wired infrastructure and the users. Such an access network must clearly accommodate all types of services expected to operate in next generation systems, including real-time services. However, wireless multihop networks have traditionally had problems meeting the delay requirements posed by such services.

    In this thesis, we will study the delay performance through analysis and simulation of such a network, based on the Virtual Cellular Network proposal [1], in which geographically fixed wireless relays are deployed to act as both network nodes and user relays.

  • 234.
    Galassi De Orchi, Tommaso
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    A Security Study for Non-Internet Connected Managed Software2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This master thesis project aims to improve the security of managed software developed at SCANIA's research and development group NEVE. The thesis will present several security schemes that can be effective against tampering, theft, and reverse engineering of application. The schemes presented were selected to ensure confidentiality, integrity, authenticity, and authentication of applications. NEVE’s software will be analyzed and compared against state of the art solutions. A theoretical threat analysis will be presented, corroborated by empirical reverse engineering attacks. The final part of this thesis introduces a new security scheme for C# .NET programs operating without requiring an internet connection.

  • 235.
    Ganjalizadeh, Milad
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Reliability for Hard Real-time Communication in Packet-switched Networks2014Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Nowadays, different companies use Ethernet for different industrial applications. Industrial Ethernet has some specific requirements due to its specific applications and environmental conditions which is the reason that makes it different than corporate LANs. Real-time guarantees, which require precise synchronization between all communication devices, as well as reliability are the keys in performance evaluation of different methods [1].  High bandwidth, high availability, reduced cost, support for open infrastructure as well as deterministic architecture make packet-switched networks suitable for a variety of different industrial distributed hard real-time applications. Although research on guaranteeing timing requirements in packet-switched networks has been done, communication reliability is still an open problem for hard real-time applications.

    In this thesis report, a framework for enhancing the reliability in multihop packet-switched networks is presented. Moreover, a novel admission control mechanism using a real-time analysis is suggested to provide deadline guarantees for hard real-time traffic. A generic and flexible simulator has been implemented for the purpose of this research study to measure different defined performance metrics. This simulator can also be used for future research due to its flexibility. The performance evaluation of the proposed solution shows a possible enhancement of the message error rate by several orders of magnitude, while the decrease in network utilization stays at a reasonable level.

  • 236.
    Garbaruk, Ekaterina
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Requirement analysis of international wholesale telecommunications for Carrier Ethernet services2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The development of Internet applications, as well as new technologies to provide Internet access to users, has caused a massive increase in the amount of data traffic in networks and the need of cost-efficient solutions for various networks. This motivated the development of such technologies as Internet Protocol (IP) and Ethernet.

    Ethernet originally aimed to serve the needs of Local Area Networks. The deployment of Ethernet in metropolitan area networks worldwide (also known as Carrier Ethernet) has made it both a competitive and preferable technology in comparison to technologies such as SONET/SDH and wavelength division multiplexing (WDM).

    This thesis research investigates the requirement of various stakeholders to Carrier Ethernet technology. The following stakeholders were identified during the research: customers, standardization bodies, vendors, and providers. Each stakeholder was closely investigated and its needs, requirements and interconnection with other target groups were analysed and gathered into one communication map called Carrier Ethernet eco-system.

    Moreover this thesis identifies more specific recommendations to each stakeholder that could improve the development of Carrier Ethernet technology in general and ensure the satisfaction of the customer and leave more space for future innovation.

  • 237.
    García Hijes, Raúl
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Corporate Wireless IP Telephony2005Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [no]

    IP telefoni är definierat som transporten av telefon samtal genom ett IP nätverk. IP telefoni utnyttjar integrationen av tal och data nätverk. Dock är affärsföretag fortfarande motsträviga till att införa IP telefoni trots potentiell ökning i produktivitet och minskade kostnader. Huvud bekymren är: kan IP telefoni tillhandahålla samma nivå av prestanda med avseende på säkerhet, tillförlitlighet, och skalbarhet som traditionell telefoni? Och i så fall, är dom proklamerade fördelarna flexibilitet och rörlighet kostnadseffektiva?

    Målet för detta examensarbete är att analysera hur IP telefoni kan införas i stora affärsföretag - medan samtidigt tillhandahålla nödvändig säkerhet och främja rörlighet. Genom olika delar av detta examensarbete, analyserar vi tillämpliga teknologier, inklusive deras integrering och skötsel. Vi kommer att fokusera på de grundläggande kraven för ett affärsföretag gällande skalbarhet, tillförlitlighet, flexibilitet, hög tillgänglighet, och kostnadseffektivitet.

    Dom massiva förändringarna frambringade i och med avregleringen av telekommunikation i stort sett alla länder, affärsverksamhetens alltmer globala natur, och de progressivt kostnadseffektiva och kraftfulla underliggande teknologier bakom informations och kommunikations system har lett till ökande adoptering av IP telefoni av både privata och kommersiella användare. Detta examensarbete undersöker relevanta teknologier i samband med mycket stora utbredda affärsföretag.

  • 238.
    Ge, Tengqingqing
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Indoor Positioning System based on Bluetooth Low Energy for Blind or Visually Impaired Users: Running on a smartphone2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Blind and visually impaired (BVI) users desire an indoor navigation tool that is inexpensive, convenient, and reliable. The purpose of this thesis is to examine the feasibility of using a smartphone as a platform for such a navigation tool.

    A good navigation tool should have both a good positioning accuracy and a user-friendly interface. Thus, one focus of this thesis is to improve the performance of an indoor positioning systems running on smartphones, as compared to existing systems. Another focus is to customize this indoor positioning system specifically for BVI users.  The proposed indoor positioning system is based upon Bluetooth Low Energy (BLE). It consists of two parts: BLE beacons deployed in the user’s environment and an Android phone which calculates its position and provides navigation assistance by audio and vibration.

    Two versions of the positioning software were developed based on different algorithms. One version uses a hybrid technique combining triangulation and fingerprinting. This version achieves a positioning accuracy of 1.83 meter, and volunteers (blind-folded sighted people) took on average 91.7 seconds to complete a complex 12-meter route. The other version uses a proximity algorithm, thus it does not give as accurate positioning results. With this algorithm, a blind user was able to finish a route of 115 meters consisting of two different floors in a building including entering/exiting an elevator and multiple office doors in 4 minutes 48 seconds. The blind user found the product to be helpful and user-friendly.

    Finally, we draw the conclusion that a smartphone can be a good platform for a BVI navigation tool, under the condition that the algorithm is proximity based and navigation utilizes a priori information about the environment. Another insight we gained is that we should put beacons on braille signs so that blind people can find them by using the navigation app.

  • 239.
    Giacometti, Sabrina
    KTH, Tidigare Institutioner, Teleinformatik.
    WAP Security2000Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This Master's Thesis gives a brief introduction to the Wireless Application Protocol: the motivation for using WAP, the WAP model, the architecture and protocols, some services, and WAP solution benefits. The project focuses then on security in WAP, in particular it discusses the different solutions of WAP security: WTLS, WIM, WPKI, WMLScrypto library, and WPP (for providing End-to-End security).

    A short chapter is dedicated to the WAP Gateway/Proxy 1.0, to understand its architecture, use and functionality in WAP.</p> Security services and functionality offered by WAP, for secure e-commerce and remote access, are studied: encryption, user and host authentication, packet integrity protection, Network Access Translator, and non-repudiation of origin.

    Finally the security in WAP is compared to TLS and IPSec, which are two different existing solutions. In the part called 'Future work' there is a description of some problems that WAP has and possible extensions that can be made.

    In the appendix, a possible service offered by WAP is shown. A WAP client accesses the Ericsson Corporate Network by a router that permits it to connect to a WAP Gateway, to fetch WML pages and to send commands to an Ericsson e-box. This permits the user to turn on and off an item of electric home equipment (for example switch on and off a lamp).

  • 240.
    Gillberg, Kristian
    et al.
    KTH, Tidigare Institutioner, Teleinformatik. KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Unestrand, Christer
    KTH, Tidigare Institutioner, Teleinformatik. KTH, Skolan för informations- och kommunikationsteknik (ICT).
    HotSpot: A Multi-agent System forDynamic Resource Allocation: Location and Discovery of Resources and Services Using Automated Negotiation for Resource Allocation1997Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Computer networks are to an increasing extent becoming interconnected making it possible to access a vast array of remote resources. In this context, we have explored how a multi-agent system could be designed to support the use of the resources in such a way as to enable complete resource sharing and dynamic resource allocation. This allows providers to sell access to resources which enables users to utilize otherwise private resources. In this thesis we introduce a system called HotSpot in which resources are managed by agents and are allocated using automated negotiation.

    An infrastructure supporting the discovery and location of agents and resources has been designed and is realized by special system services. The emphasis has been on specifying how the entities that constitute these services should behave and interact in order to maintain a high level of scalability, robustness, flexibility, and autonomy in an agent environment. The negotiation scheme in HotSpot is based on automated contracting and the contributions in this area are models for the implementation of the agents involved. These models describe algorithms that can be used for announcement- and bid evaluation. A prototype including the basic ideas has been implemented. The implementation indicates that the HotSpot system provides the basic functionality needed to enable complete resource sharing.

  • 241.
    Gioacchino Cascella, Roberto
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Reconfigurable Application Networks through Peer Discovery and Handovers2003Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This Master thesis work was carried out at theWireless Center at KTH and it is part of a pilot project. This thesis is conducted for the Institute for Microelectronics and Information Technology (IMIT) at the Royal Institute of Technology (KTH) in Stockholm (Sweden) and for the Department of Telecommunications at Politecnico di Torino in Turin (Italy).

    This thesis addresses an area with significant potential for offering services to mobile users. In such a scenario users should have minimal interaction with applications which, by taking into account available context information, should be able to make decisions, such as setting up delivery paths between peers without requiring a third party for the negotiation.

    In wireless reconfigurable networks, the mobile users are on the move and must deal with dynamic changes of network resources. In such a network, mobile users should be able to contact other peers or resources by using the current route. Thus although manual configuration of the network is a possible solution, it is not easily used because of the dynamic properties of the system which would demand too much user interaction. However, existing discovery protocols fall short of accomodating the complexity of reconfigurable and heterogeneous networks.

    The primary objective of this thesis work was to investigate a new approach at the application level for signaling by taking advantage of SIP’s features. The Session Initiation Protocol (SIP) is used to provide naming and localization of the user, and to provide functionality to invite users to establish sessions and to agree on communication parameters. The Specific Event Notification of the SIP protocol provides a framework for the notification of specific events and I believed that it could be instantiated as solution to the problem for reconfigurable application networks.

    This thesis proposes a method for providing localization information to SIP User Agents in order to establish sessions for service discovery. Furthermore, this method should consider context meta-data to design strategies effective in heterogeneous networks. A viable solution must support (re)location of users at the application layer when they roam between different wireless networks, such as GPRS and WLAN. An analysis of the implications of the proposed model is presented; in this analysis emphasis has been placed on how this model interacts with existing services.

  • 242.
    Gkikas, Nikolaos
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Data Transfer and Management through the IKAROS framework: Adopting an asynchronous non-blocking event driven approach to implement the Elastic-Transfer's IMAP client-server connection2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Given the current state of input/output (I/O) and storage devices in petascale systems, incremental solutions would be ineffective when implemented in exascale environments. According to the "The International Exascale Software Roadmap", by Dongarra, et al. existing I/O architectures are not sufficiently scalable, especially because current shared file systems have limitations when used in large-scale environments. These limitations are:

    • Bandwidth does not scale economically to large-scale systems,
    • I/O traffic on the high speed network can impact on and be influenced by other unrelated jobs, and
    • I/O traffic on the storage server can impact on and be influenced by other unrelated jobs.

    Future applications on exascale computers will require I/O bandwidth proportional to their computational capabilities. To avoid these limitations C. Filippidis, C. Markou, and Y. Cotronis proposed the IKAROS framework.

    In this thesis project, the capabilities of the publicly available elastic-transfer (eT) module which was directly derived from the IKAROS, will be expanded.

    The eT uses Google’s Gmail service as an utility for efficient meta-data management. Gmail is based on the IMAP protocol, and the existing version of the eT framework implements the Internet Message Access Protocol (IMAP) client-server connection through the ‘‘Inbox’’ module from the Node Package Manager (NPM) of the Node.js programming language. This module was used as a proof of concept, but in a production environment this implementation undermines the system’s scalability and there is an inefficient allocation of the system’s resources when a large number of concurrent requests arrive at the eT′s meta-data server (MDS) at the same time. This thesis solves this problem by adopting an asynchronous non-blocking event driven approach to implement the IMAP client-server connection. This was done by integrating and modifying the ‘‘Imap’’ NPM module from the NPM repository to suit the eT framework.

    Additionally, since the JavaScript Object Notation (JSON) format has become one of the most widespread data-interchange formats, eT′s meta-data scheme is appropriately modified to make the system’s meta-data easily parsed as JSON objects. This feature creates a framework with wider compatibility and interoperability with external systems.

    The evaluation and operational behavior of the new module was tested through a set of data transfer experiments over a wide area network environment. These experiments were performed to ensure that the changes in the system’s architecture did not affected its performance.

  • 243.
    Glauser, Ivan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Improving Alarm Interoperability with External Systems for a Wearable Command Unit Using Service-Oriented Architecture2007Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis investigates different aspects of implementing a Service-Oriented Architecture (SOA) for an alarm and crisis management system called Wearable Command Unit (WCU) developed by Saab Security Systems.

    The WCU system must be able to integrate easily with external systems in order to move into new markets and survive as a product. The focus of this report is a general solution for communicating alarm information from external systems to the WCU. A given requirement was that the solution must be based on SOA. Therefore, the concept of SOA is investigated and its applicability is considered for the WCU architecture.

    A design proposal based on a combination of open information and communication technologies was made to show how WCU may use SOA to receive alarm information from external systems. The design proposal was evaluated by a load test as well as comparing its conformance to SOA. The load test showed that the proposed solution can process incoming messages at a rate of 2 ms per message when client and server are run on the same machine. The result of the comparison showed that the WCU can, with small modifications, apply a SOA.

    While this thesis has only investigated the use of SOA in the context of alarm information, there is a clear trend toward integrating information for diverse systems to enable users to have better quality information. Providing first responders with the information that they need, when and where they need it can enable them to save lives, save property, and reduce the risk to the public of incidents.

    An important result from this thesis is the observation that a system that needs to integrate with many distinct systems can be better prepared if made SOA conformant. This requires the system to have an interface towards other systems based on platform independent protocols. Systems such as the WCU, which are based on Windows Communication Foundation (WCF), can easily add such an interface by configuring WCF in an appropriate way.

  • 244.
    Glifberg, Fredrik
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Optimisation of End-to-End TCP Performance in A UMTS Network2003Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Due to the FEC and ARQ mechanisms in UMTS the wireless part will not introduce loss, but instead introduces latency. This thesis aims to optimize the radio network (RAN) parameters in UMTS affecting TCP and then to optimize the parameters in TCP to perform better in this network.

    The tests have been performed in a live 3G network. A traffic model has been implemented into a client/server allowing us to simulate a UMTS customer in the cell, with which we can test different parameter settings. Radio parameters controlling radio connection supervision, channel switching, and power control’s BLER-target have been examined. Performance has been measured in terms of throughput and cell capacity.

    The results show that we can improve TCP performance by 25% with better static parameter settings. However, the system would be even better with a dynamic approach that would adjust the RAN parameter settings to better match the current load in the cell. In this way the performance/user can be increased significantly and as an example for one user the average throughput given a specific traffic pattern can be increased from 65 kbps up to 300 - 320 kbps.

  • 245.
    Gollbo, Simon
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Signaler och System.
    Sköld, Adam
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Signaler och System.
    Base stations for communication in obstructed environments2015Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    The purpose of this project was to produce signal relay stations that could receive information via 2.4 GHz radio and relay the information to a designated target station. If a relay station was located outside of signal range for the target station it was supposed to utilize other relay stations to transfer the information to the target station, so called multi-hop.

    The would-be application of the relay stations was orienteering. When an orienteer punches a checkpoint the signal stations would relay information of who punched the control, when it was punched and the checkpoint that was punched to the speaker tower in the goal area.

    The work resulted in prototypes which fulfilled the statement of purpose and was tested at an orienteering competition with satisfactory results. The performance of the prototypes was tested and found adequate for the would-be application.

  • 246.
    Gradh, Anders
    Försvarshögskolan.
    En stabs nätverkstrafik: En analys av användningen av datornätverkskapacitet i en operativ stab under övningen VIKING 112015Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    FM köpte satellitkapacitet för närmare 20 miljoner kronor under 2014 för utbildning, övning och internationella operationer. Enligt HKV räcker dock inte upphandlad kapacitet för att täcka behoven ute hos förbanden.

    Syftet med denna studie är att ta reda på mer hur kapacitetsanvändningen ser ut vid en operativ stab utifrån deras arbete och därigenom se om det finns någon militär nytta att vinna kopplad till kapacitetsanvändning.

    Utgångspunkten för arbetet är insamlad information om datornätverkstrafiken i de olika nätverken. Detta kvantitativa data jämförs med stabens arbete utifrån kvantitativ och kvalitativ data i krigsdagbok, styrdokument och deltagande studie.

    Studien visar på att kapacitetsanvändningen ej är relaterad till stabens arbete utan snarare är kopplad till när personal är på plats och personalens internetanvändning. Studien pekar på att det kan finnas en potential att få mer militär nytta, dock måste mekanismer för prioritering i nätverket införas och vidare studier avseende trafiken genomföras.

  • 247.
    Gran, Mikael
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Karlsson, Claes
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Survey of VMware NSX Virtualized Network Platform: Utvärdering av VMware NSX Virtualized Network Platform2017Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Atea Eskilstuna hade behovet av en plattform som kan förenkla och minska antalet konfigurationer vid implementation av kunder. Arbetet gick ut på att utvärdera plattformen VMware NSX och jämföra det mot traditionella nätverkslösningar. I dagens datacenter är virtualisering en viktig del av dess verksamhet. Användandet av virtualisering optimerar hanteringen av hårdvaru-resurser och kostnader. Virtualisering har hittills främst fokuserat på hantering av servrar och klienter, vilket har passerat nätverksutvecklingen, och därför har det uppstått vissa problem med traditionella datacenter gällande trafikflöden, säkerhet och implementering. Datacenter har tidigare varit optimerade för trafik som ska in eller ut ur datacentret. Detta har lett till att brandväggar och säkerhetspolicies ofta placerats vid datacentrets kant. I dagens datacenter har det däremot blivit en ökning på trafik mellan enheter inom datacentret som behöver skyddas. Denna typ av interna säkerhet kan uppnås av interna policies på samtliga nätverksenheter, dock blir det ohållbart vid implementation då antalet konfigurationspunkter i nätverket ökar. Dessa problem kan hanteras med hjälp av VMware NSX som virtualiserar nätverksenheter och centraliserar administration. NSX har en distribuerad brandväggs-funktion vilket medför att policies kan appliceras direkt på virtuella maskiner och virtuella routrar, från en central konfigurationspunkt. Detta ökar säkerheten och minskar implementationstiden jämfört med traditionella datacenter. Arbetet fokuserar på hur NSX arbetar till skillnad från fysiska nätverksenheter samt hur NSX hanterar frågor som trafikflöden, säkerhet och automation. För dessa ändamål byggdes en laborationsmiljö i Ravellos molntjänst med flertalet virtuella maskiner och en litteraturstudie utfördes. Laborationsmiljön användes för att sätta upp kunder med hjälp av virtuella nätverksenheter och virtuella maskiner. Laborationsmiljön användes som referens för hur implementation av NSX och dess funktioner går till. Litteraturstudien fokuserar på vad som är möjligt i NSX och vilka för- och nackdelar som finns med NSX jämfört med traditionella datacenter. Resultaten visade på att den enda nackdelen med NSX var dess licenskostnader.

  • 248.
    Granberg, Tony
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Mjukvara för träning av routersyntax2015Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Det här arbetet handlar om en mjukvara vars mål är att tillhandahålla syntaxträning inom routeradministration inriktad mot målgruppen studenter. Mjukvaran har programmerats från grunden i programmeringsspråket Python och är menad att erbjuda ett simplistiskt användargränsnitt. Programmeringen har resulterat i ett program som döpts till Routersyntax och består av två delar: ett klientprogram och ett serverprogram. Både klientprogrammet och serverprogrammet går att installera och köra i flera olika operativsystemmiljöer, med främsta fokus på Windows, Ubuntu Linux och OS X. Det är simplistiskt utformat, enkelt att installera och köra, samt gratis att använda för studenter.

    Förhoppningen är att användaren med hjälp av syntaxträningsmjukvaran ska få en chans att träna sina färdigheter i att skriva routerkommandon för användning av studenter i universitetskurser.


  • 249.
    Grankvist, Henrik
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Kvarnström, William
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Security Feature Test for Ethernet Switches2014Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    A new standard in network security for industrial control systems is about to be released by a number of working groups within the ISA99 organization. ABB has a certification program for network components that may be used together with the control system 800xA, which is named Industrial IT Certification. ABB now wants to introduce formal testing of network component’s security features according to this standard.The document IEC 62443-4-2 is the document within this standard that describes how the system requirements should be implemented on network components. This document is still a draft, so the document IEC 62443-3-3 which describes how the system requirements should be implemented on a whole industrial control system has been used to estimate the content of IEC 62443-4-2 when it is finished. Out of these two documents the requirements has been broken down into a test description which contains a number of tests to check which security features a switch has and that they work as described. Together with the test description, a test record template has been created to be used for documenting the result from the tests.Finally a comparison was made where the results from a number of different network equipment could be compared against each other regarding their security features. This comparison will in the future make it easier for ABB’s customers when they are in the process of buying new network equipment.In short the more expensive brands of switches have in general more security features implemented, and desktop switches has more security features implemented than industrial switches, with certain exceptions. The buyer needs to ask himself if he really needs all the security features. The choice of what switch to buy all depends on the placement of the switch and what purpose it should fulfill.

  • 250.
    Gritsis, Konstantin
    KTH, Tidigare Institutioner, Teleinformatik.
    Management of PDH network equipment1995Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
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