Endre søk
Begrens søket
3456789 251 - 300 of 832
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Treff pr side
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
Merk
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 251.
    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.

  • 252.
    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.

  • 253.
    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.

  • 254.
    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.

  • 255.
    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.

  • 256.
    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.

  • 257.
    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.


  • 258.
    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.

  • 259.
    Gritsis, Konstantin
    KTH, Tidigare Institutioner, Teleinformatik.
    Management of PDH network equipment1995Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
  • 260.
    Groleau, Romain
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Multipath Routing with Load Balancing in Wireless Ad Hoc Networks2005Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In recent years, routing research concerning wired networks has focused on minimizing the maximum utilization of the links which is equivalent to reducing the number of bottlenecks while supporting the same traffic demands. This can be achieved using multipath routing with load balancing instead of single path routing using of routing optimizers. However, in the domain of ad hoc networks multipath routing has not been investigated in depth. We would like to develop an analogy between wired and wireless networks, but before that we need to identify the major differences between these two in the case of multipath routing. First, in order to increase the network throughput, the multiple paths have to be independent so they don't share the same bottlenecks. Then, due to radio propagation properties the link capacity is not constant. So using the maximum utilization metric for wireless networks is not suitable. Based on the research done in wired networks, which has shown that using multiple paths with load balancing policies between sourcedestination pairs can minimize the maximum utilization of the links, we investigate if this is applicable to ad hoc networks.

    This paper proposes a multipath routing algorithm with a load balancing policy. The results obtained from an indoor 802.11g network highlight two major points. The maximum throughput is not achieved with multipath routing, but with single path routing. However, the results on the delivery ratio are encouraging, indeed we observe a real improvement thanks to our multipath routing algorithm.

  • 261.
    Grund, Olof
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Trådlösa tvättrobotar: Trådlös internetåtkomst för Envirologic ABs tvättrobotar.2014Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Envirologic AB tillverkar tvättrobotar för diverse miljöer. Idag behöver man ta sig tillroboten för att konfigurera robotens inställningar. Istället vill man nu att trådlöstkunna göra ändringar över internet. På marknaden finns det en mängd olika varianterav objekt som kan koppla upp sig mot nätverk men till detta ställs det även en delkrav som att roboten måste enkelt kunna koppla upp sig mot ett lokalt Wifi och gåförbi lokala brandväggar m.m. Rent konstruktionsmässigt måste lösningen ha antenneroch roboten måste fortsatt vara IP67-klassad.

    Lösningen heter Tosibox. Tosibox använder sig av VPN-teknik och kan enkeltinstalleras i roboten med hjälp av dess två antenner. Vidare har Tosibox utveckladmjukvara för att enkelt nå roboten över internet.

  • 262.
    Gründl, Gabriel Josef
    KTH, Tidigare Institutioner, Teleinformatik.
    Modulation Techniques and Medium Access Control Protocols for Wireless Access to ATM1999Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This report covers modulation techniques and medium access control protocols for wireless ATM.Important aspects of the wave propagation, path loss and time dispersion, are discussed in conjunctionwith the Orthogonal Frequency Division Multiplex (FDM) transmission scheme. In OFDM correct detec-tion relies heavily on the orthogonality of the carriers. When this constraint is met classical modulationmethods as M-PSK and M-QAM can be used. Wireless ATM requires a considerable amount of bandwidth.The frequency reuse factor is made small by using building walls as isolation between clusters. Trafficmodels suited to model arrival processes at ATM-multiplexers are developed to use with system perfor-mance analysis in the multiuser environment. Multiplexer buffer size requirements are found to be higherwith bursty sources. ATM switching is based on multiplexing of small data units or cells. When developingmethods to interconnect mobile units with wired ATM networks this property should be considered. In thiswork a medium access control protocol using dynamic capacity allocation and time division multiplex (TDM) is introduced, Dynamic Capacity Allocation / WireLess Network MAC (DCA/WLNMAC). The pro-tocol supports error free packet delivery and automatic source rate adaption. It is shown that the packetloss ratio easily can be made small by choosing the correct adaptation rate.

  • 263.
    Gu, Yuqing
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Home Wi-Fi Optimization Application Front-end Design2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In this information society, wireless network is an indispensable technology supporting the daily information communication and various interaction services. With the motivation to improve the user experience of Wi-Fi service, this thesis presents the front-end development process of a visualization application for home Wi-Fi testing and optimization. To provide the desired service to the users, it is important to understand what they need. With prompt feedback, the development process can have much more customized schedule and specific aim. In this thesis, different methods are adopted to get the valuable feedbacks from potential users. Brainstorming and originality interview support the basic designing of application, which is presented by the wireframe prototype. The prototype were used for a test-run and get feedbacks in order to develop a web application front-end assimilating the ideas and suggestions from real users. As more detailed functionality are designed, the feasibility and practicability should be investigated. Questionnaires are used to do larger scale ranges of user investigation. The front-end is designed using HTML, CSS and JavaScript with Bootstrap framework. The elements within all the pages could be able to interact with each other to give the customers a visualized experienced of service. The web application provides the users with the functions to test the real-time Wi-Fi performance, check the performance trend of data history from a specific time period and get useful optimization solutions. The designing is aiming to synthesize enough accessible information and provide the users with self-helpful testing and optimization of home Wi-Fi, which can increase the efficiency of technical support and reduce the workload of customer service.

  • 264.
    Guerin, Pascal
    KTH, Tidigare Institutioner, Teleinformatik.
    RadioNet Driver Implementationfor the Mobile INTernet Router (Walkstation II project)1994Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The Mobile INTernet router (MINT for short) is a core element of the Walkstation II Project. Its purpose is to link via a radio resource one or many mobile hosts, the latter are either independant or connected together forming a isolated subnetwork. The MINT has a communication device consisting of an Ethernet Controller and a radio tranceiver, currently working at 2GHz. The RadioNet Driver, a device driver is used control these pieces of hardware. Progress has been slow. Initial work involved exploring the MINT's programming environment (cross-compiler, debugger) and doing some experiments with the MINTs. Next, a dummy RadioNet driver was written to become familiar with programming in the (SunOS) kernel. Then the LANCE driver for the MACH kernel was modified, resulting in the RadioNet driver. This talk will decribe the tools and the current status of the RadioNet driver.

  • 265.
    Guitérrez Barquín, Jesús Miguel
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Network Independent Quality of Service: The role of Authentication, Authorization, and Accouting in a roaming environment2006Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    With the increasing shift to the Internet Protocol [3] for all networks and the desire of telecommunications service providers to offer new value to their customers, the need exists to coordinate the delivery of end-to-end quality of service so that providers may offer new services to support their customer’s applications. The key objective of the EuQoS project is to research, integrate, test, validate, and demonstrate end-to-end QoS technologies to support advanced QoS-aware applications over multiple, heterogeneous research, scientific, and industrial network domains. End-to-end quality of service support for multiple applications is a great added value and could become the next major growth spurt in the telecommunications industry.

    A crucial requirement for the QoS model is that it must not add significant complexity to the existing mechanisms and must be compatible with legacy applications and equipment. Proxy signaling handlers will be used to satisfy the latter constraint.

    This thesis analyzes possible roaming scenarios and how Authentication, Authorization, and Accounting should be tackled. I seek to provide reasonable solutions and to consider the current environment, always trying to re-use, when possible, the existing architecture and components.

  • 266.
    Gunnarsson, Mikael
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Truck-Trailer Wireless Connections2001Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Scania Infotronics is a subsidiary of Scania AB that works with IT-solutions for heavy vehicles. In one of Scania Infotronics’ projects a handheld computer is installed in a truck and connected to the vehicle’s data bus. From this data bus it is possible to collect a vast amount of data that is generated by the truck. The problem today is that the data bus does not reach into any trailers that are coupled to the truck, and no data can therefore be gathered from the trailers. A wireless link between the truck and the trailer would solve this problem. Possibly the unit installed in the trailer should be made portable in order for it to be easily moved between different trailers.

    This project will examine some of the technologies currently available that could be used to solve this. This will include studies of technologies such as DECT, BlueTooth. Some other technologies will be discarded in an early stage and others will be more thoroughly examined. During the implementation phase a prototype will be created for testing and evaluation.

    There has already been lots of work done as some of these wireless technologies have been around for a while and they are well standardized and widely deployed. What makes this project difficult is choosing the most suited technology for use in the very special environment that the truck and its trailer constitute. Furthermore the hardware and the software necessary are expected to raise interesting problems requiring new solutions.

  • 267.
    Guo, Jiabing
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Design and implementation of LTE-A and 5G kernel algorithms on SIMD vector processor2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    With the wide spread of wireless technology, the time for 4G has arrived, and 5G will appear not so far in the future. However, no matter whether it is 4G or 5G, low latency is a mandatory requirement for baseband processing at base stations for modern cellular standards. In particular, in a future 5G wireless system, with massive MIMO and ultra-dense cells, the demand for low round trip latency between the mobile device and the base station requires a baseband processing delay of 1 ms. This is 10 percentage of today’s LTE-A round trip latency, while at the same time massive MIMO requires large-scale matrix computations. This is especially true for channel estimation and MIMO detection at the base station. Therefore, it is essential to ensure low latency for the user data traffic.

    In this master’s thesis, LTE/LTE-A uplink physical layer processing is examined, especially the process of channel estimation and MIMO detection. In order to analyze this processing we compare two conventional algorithms’ performance and complexity for channel estimation and MIMO detection. The key aspect which affects the algorithms’ speed is identified as the need for “massive complex matrix inversion”. A parallel coding scheme is proposed to implement a matrix inversion kernel algorithm on a single instruction multiple data stream (SIMD) vector processor.

    The major contribution of this thesis is implementation and evaluation of a parallel massive complex matrix inversion algorithm. Two aspects have been addressed: the selection of the algorithm to perform this matrix computation and the implementation of a highly parallel version of this algorithm.

  • 268.
    Gustafsson, Magnus
    Linköpings universitet, Institutionen för datavetenskap, RTSLAB - Laboratoriet för realtidssystem.
    Lightweight M2M Solution on Android Platform2011Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Machine-to-machine communication (M2M) is a generic term for technologies dealing with autonomous communication between machines. For the last 10 years a wide range of business areas utilize a variety of different M2M solutions for remote management of equipment. Common for almost all of those solutions is that they are expensive and require the infrastructure to be adapted to them. They are also usually built out of several different systems working together and thus there are several systems that require maintenance.

    This thesis investigates the possibility to develop a lightweight alternative to existing M2M solutions using only common devices and protocols. Lightweight here means that the system should be flexible, have a low cost for set-up and operation and that both ends should be mobile. By developing a lightweight M2M architecture the technology may become available in new business areas and new types of services may arise. 

    In the thesis a prototype is implemented. The purpose of the prototype is to practically verify whether a lightweight M2M solution is possible to develop in this manner. The solution uses the Android platform for back-end and user interface and a Cinterion TC65T as slave device to which the sensors can be connected. The implemented system is limited in terms of security and performance but still acts as a proof of concept for this kind of M2M solution.

  • 269.
    Gustavsson, Josef
    Högskolan i Jönköping, Tekniska Högskolan, JTH, Data- och elektroteknik.
    Aktiesammanställare med teknisk analys och simulation2013Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Websites today only offer simpler form of technical analysis and are not fun to use, therefore student decided to build a website that makes technical analysis a bit more fun by giving user possibility to experiment with settings for technical indicators and also see clear visible results from analysis. Student decided to build website in ASP.NET. Technical indicators for this project only consist of those who give buy and sell-signals via cross-over, no divergence or pattern finding.This project has three questions that define this project. It’s important that there is good functionality so that performing an analysis is perceived as simple, one question is therefore; what functionality for website is needed in order for analysis to be perceived as more simple?Technical analysis is a pretty complex subject and demands an interface that is perceived as easy to understand and easy to use, it’s therefore important that the interface is well designed, second question is therefore; how should the interface be designed to be user-friendly?When systems grow large they often become hard to develop and later on unmaintainable because of the accumulated complexity and dependency between classes, the code is a mess, the last question is therefore; how can the systems complexity be eased with object-oriented design principles?Jakob Nielsens ten heuristics for User Interface Design were used as inspiration for designing the interface for the website. The system design follows SOLID principles, some pattern-design were also used because pattern-design often fulfills SOLID principles or makes for pretty good solutions in regular code-problems.At the beginning of the project the student did a small research to find out what was needed in order to complete project. Work-method for project follows agile development where decisions were made on a weekly basis. The project was divided into three phases where each phase was strongly coupled to a specific area of responsibility. Prototypes for interface were made and used as a basis for the resulting interface.The project led to a working website with good functionality. Filter was considered as important in order to ease shaping of analysis because the user could more easily sort and pick stock. The student assumed that the user would want fast and easy access to their stock so portfolio management were implemented so that user could more easily get to stock that was considered as favorites. The interface follows to a big extent Jakob Nielsens ten heuristics for User Interface Design and is proven by comparing interface with principles. The same goes for design of the system, design is proven by comparing with principles, still to this day system is considered easy to continue development.Student made the conclusion that SOLID principles were very important in order for the system to maintain its health and took experience from these principles. Student became happy with the interface but more focus could’ve been given for a more interactive interface because it might’ve been perceived as more intuitive.

  • 270.
    Gutierrez Lopez, Armando
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Mulas Viela, Ignacio Manuel
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Automated Telecommunication Software Testing: An automated model generator for Model-Based Testing2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In Model-Based Testing (MBT) the main goal is to test a system by designing models which describe the functionality of the system to test. Subsequently, test cases are obtained from the model, and these test cases can be executed automatically.

    Experience has shown that the learning curve for learning MBT can be steep - especially for people who do not have previous programming experience. This is because the language used to design models uses programming language concepts. In this thesis we describe a tool which automatically generates models, given an initial set of requirements. The advantage of this tool is that users do not need to learn a model-based testing language to design models, but instead they must learn to use a high-level of abstraction and a Graphical User Interface to specify their test cases.

    We demonstrate the value of the tool by using it to design models that generate test cases for telecommunications system, but show that this tool can be adapted for use in testing similar systems. The application of this tool can facilitate traditional phase-based software development methods, by saving a considerable amount of time and resources. In addition, when applied to agile software development, the reduced time required for testing because of the use of our tool helps shortening the feedback loops between designing and testing, thus increasing team efficiency within every iteration.

  • 271.
    Gutti, Krishna
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Low cost secure network connectivity for a municipal organization2005Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Wireless Local Area Networks (WLANs) based on 802.11 technology were initially conceived with the aim of providing wireless connectivity to client devices in limited areas, such as office buildings, homes, etc. or in places where wires are too expensive to be placed. This ‘anywhere’ connectivity is said to have improved worker’s productivity by allowing one to work flexibly from various places besides one’s desk. Currently we are witnessing the growth of both public and private networks based on WLAN technology. Such hotspots are usually limited to the network owner’s premises such as her office, campus, etc. This limits the total coverage area of this network. It is often not economically feasible for a network access provider to install Access Points at all places that a network user might go. This has become a problem for many network access providers; a sensible solution would be to collectively address the problem by entering into roaming agreements as is already done by most Wide Area Wireless Network providers. Such operator specific roaming agreements can provide nearly continuous coverage over a much wider area such as an entire city. One of the goals of this project was to study potential cost effective technical solutions that provide WLAN access to City of Stockholm’s network based on 802.11 technologies; including evaluation from different technical aspects (e.g., capacity enhancements, improvements in handover latency, etc). Proper deployment and management strategies were also evaluated. Technologies permitting differentiated services for users, enabling provisioning of Voice over Wireless Local Area Network (VoWLAN) services and other interactive services were studied. Technologies for authentication, authorization and accounting were studied. Additionally technical means of providing secure access to the wireless network were investigated. Evaluation of architectures that allow inter-operator roaming were made.

    Today’s corporate users are increasingly mobile and there is a need to provide secure access to corporate data to these mobile users. The coverage offered by WLAN networks even with large roaming agreements would still have coverage gaps which can be reduced by relying on the 3G networks which are being widely deployed. Virtual Private Network technologies are successfully used for providing secure remote access to data and Mobile IP technology provides application persistence to mobile users even while switching between networks (e.g., WLAN to 3G). There is a need for them to co-exist in order to provide secure, mobile access to data. Such secure mobile access could also be provided without relying on the above, standardised solutions. A goal of this master’s thesis was to evaluate the technical solutions to enable such secure, mobile access to data. Current products were evaluated and a suggestion of suitable products for the City of Stockholm was given.

    The above solutions together would provide the City of Stockholm with secure wireless network connectivity[.]

  • 272.
    Guulay, Biniam Gebregergs
    KTH, Skolan för elektro- och systemteknik (EES).
    CheesePi: Measuring Home Network Performance Using Dedicated Hardware Devices2015Independent thesis Advanced level (degree of Master (Two Years)), 80 poäng / 120 hpOppgave
    Abstract [en]

    Internet users may not get the service quality promised by theirproviders, and also may not know what service they can receive.When users experience poor Internet connection performance, itis not easy to identify the source of the problem. We developCheesePi, a distributed measurement system that measures theInternet connection experience of home users based on some net-work performance attributes (e.g. latency, packet loss rate, andWiFi signal quality). The CheesePi runs on a Raspberry Pi (acredit card sized computer) connected to the user’s home networkas a measurement agent. It is important to measure the networkperformance from the user’s side since it is difficult to measureeach individual’s link from the operator (provider) side. Eachmeasurement agent conducts measurement periodically withoutdisturbing the user’s Internet quality. Measurements are con-ducted during popular media events from SICS (Swedish Insti-tute of Computer Science) and student accommodations. Themeasurement results show customers with an Ethernet connectionexperienced significantly better latency and packet loss comparedto WiFi users. In most of the measurements users at SICS per-ceived better latency and packet loss compared to the users at thestudent accommodation. We also quantify how customers experi-enced lower performance when streaming from websites which donot use CDN technology compared to the websites which do useCDN, particularly during popular media events.

  • 273.
    Gyllhamn, Claes
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Centraliserad styrning av åtkomstlistor2011Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [en]

    Can the Danish "Aftalesystemet", a system with the intention to simplify the use of services within health care, be used in Sweden? This project has investigated the possibility by installing and testing the system and explored its functions to detect any eventual problems. Analyses were made of the system's graphical part and the underlying code to see in greater detail how the communication between units occurred, since no actual documentation of it existed. Discussions with the developers took place regarding how the current system works and how further development should continue. In order to test the system, a completely virtual environment was used. Server, clients and routers were virtualized with VirtualBox and GNS3 in order to not disrupt any ongoing services. The results show that because of how the Danish infrastructure is constructed, and how the system is developed to function primarily in a Danish infrastructure, some changes are needed regarding the design of the database, the GUI and the generation of access lists. Because MedCom and Inera are cooperating on this project, some functions will only be available in either language. However, the plan is that the system will be generalized to such a degree in the future that it can be used cooperatively by several countries.

  • 274. Gyllsdorff, Niclas
    Distributed machine learning for embedded devices2018Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The goal of the master thesis is to investigate the feasibility ofhaving distributed machine learning on embedded devices and toanalyse how the architecture of such a system can look like. A systemis proposed which enables machine learning running on multipleembedded devices to communicate with an end application. Theapplication communicates with the distributed machine learning via agateway, which decouples the application. The proposed system isimplemented as a proof of concept system, which utilizes distributedmachine learning to achieve gesture recognition. The Intel Curiemodule was selected as the embedded device, as it provides a hardwareaccelerated implementation of the machine learning algorithmsK-Nearest Neighbour and Radial Basis Function. This module alsoprovides accelerometer/gyroscope sensors for collecting gesture dataas well as Bluetooth Low Energy, which enables wireless communicationwith other devices. The implemented system shows that it is feasibleto implement distributed machine learning on embedded devices if themachine learning is hardware accelerated. If a hardware acceleratorwas not used the computational load on the embedded device willincrease, which will increase the overall power consumption. For alow powered and constrained devices, hardware accelerated machinelearning is likely the best approach to implement edge intelligence.

  • 275.
    Gårdlund, Martin
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    A Conceptual Model of Mobile Marketing for a Multinational Consumer Goods Company2005Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In the last 10 years, mobile phones have gone from being an exclusive almost unnecessary high-tech device to being an everyday item, used by billions of people around the world. The technology evolution has changed phones from a suitcase sized mobile phone imitating its stationary counterpart, to a small communication device that can perform more than twenty different tasks and is usually less than half the size of the a traditional fixed phone.

    With this massive adoption of mobile phones come business opportunities. One of these opportunities is to make use of its potential as a large scale marketing communication channel. Marketing via the mobile networks, presents a large target audience that can be compared to broadcast media such as television and radio, but despite this can still be a personal channel and hence compared to direct mail or one-to-one marketing.

    Many, both successful and failed, mobile marketing schemes have been tried, but without any definite answers and no clear action plan. Considering that much of the success of Procter & Gamble can be attributed to the company’s skill in mass marketing, there is a need within the company to research the potential advantages and disadvantages of mobile marketing. This thesis explores whether or not mobile marketing is mature enough to permanently introduce it to the marketing mix of the company.

  • 276.
    Ha, Nguyen Manh
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Gateways between ad hoc and other networks2007Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Multi-hop wireless ad hoc wireless networks have no fixed network infrastructure. Such a network consists of multiple nodes that maintain network connectivity through wireless links. Additionally, these nodes may be mobile and thus the topology of the network may change with time. It will be useful if the nodes in this network could communicate with the Internet; this can be done via gateways which in turn interconnect to the Internet.

    This functionality requires that the nodes in the ad hoc network to discover the gateway, using a gateway discovery protocol. However, a limiting factor (particularly for mobile nodes) is suing their limited energy supply provided by batteries. In order to understand the potential effect this thesis considers two key areas: internetworking between a multi-hop mobile wireless ad hoc network and the Internet and the energy utilization as a function of number of gateways and the mobility pattern of nodes. Using simulation on various mobility patterns and networks density scenarios, we show that increase the number of gateways in ad hoc network significantly improves the power efficiency of mobile node and therefore prevent network partition due to death nodes. The thesis also discusses about the impact of different environment and mobility patterns on the power consumption of mobile nodes which is a very important factor in the building and deployment of the cost-effective high performance wireless ad hoc networks.

  • 277.
    Habibovic, Sejla
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för data-, elektro- och lantmäteriteknik.
    Svensson, Per Real
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för data-, elektro- och lantmäteriteknik.
    Friköp av bostadsrättsföreningar och överföring av fastighetstillbehör: Vad avgör om anläggningslagen 12 a § tillämpas?2017Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Samverkan fastigheter emellan förekommer i flera olika former. En gemensamhetsanläggning utgör en sådan samverkansform, vilken inrättas för att tillgodose ändamål av stadigvarande betydelse för flera fastigheter. Ändamålen som en gemensamhetsanläggning inrättas för är vitt skilda och består ofta av anläggningar som utgör tillbehör till en fastighet, däribland fastighetstillbehör. Med en gemensamhetsanläggning följer rätten till utrymme för att de deltagande fastigheterna ska kunna förvalta anläggningen på ett ändamålsenligt sätt. Dock övergår inte äganderätten till de deltagande fastigheterna automatiskt vid inrättandet av en gemensamhetsanläggning.   Innan år 2002 sågs fastighet och dess tillbehör som en äganderättslig enhet, vilka enbart kunde åtskiljas genom att tillbehöret fysiskt flyttades från fastigheten. Bestämmelser som möjliggjorde överföring av fastighetstillbehör och äganderätt till anläggningssamfälligheten infördes i fastighetsbildningslagen (FBL) och anläggningslagen (AL). Även bestämmelse om möjlighet till frigörande av fastighetstillbehör infördes samtidigt i ledningsrättslagen (LL). I propositionen Överföring av fastighetstillbehör 2000/01:138 motiverades införandet av lagändringarna med att en rad oklarheter skulle kunna undvikas rörande fastighetstillbehöret. Dessa utgjordes av oklarhet kring underhållsansvar, ansvar att teckna försäkring, upplåtelse av nyttjanderätt, rätt att bygga om och bygga ut, samt utnyttjande av pantsättningsmöjligheten. 

     Att äga sin egen fastighet har alltid varit viktigt, inte enbart för den enskilde individen, utan även för samhällets utveckling. Ägandet skapar incitament att lägga ner tid, energi och pengar i sin fastighet, vilket i sin tur genererar ett högre fastighetsvärde. Trots detta är bostadsrätten en vanlig bostadsform i Sverige. Möjlighet finns dock att genom likvidation av bostadsrättsföreningen och avstyckning av fastigheten bilda nya enskilda fastigheter. För de utrymmen och anläggningar som tidigare varit gemensamma kvarstår dock behovet av att även i fortsättning kunna utnyttjas gemensamt. I praktiken är det endast fastighetsgränserna och ägandeformen som ändrats, inte de fysiska förutsättningarna. Genom inrättande av en gemensamhetsanläggning tillgodoses detta behov. För att även kunna överföra äganderätten till de deltagande fastigheterna finns möjligheten att tillämpa AL 12 a §.   Denna studie undersöker vad som varit avgörande för om AL 12 a § tillämpats och vilka fastighetstillbehör som vanligen överförts. För gemensamhetsanläggningar är ansvar ett centralt begrepp. Studien undersöker hur ansvaret kring försäkringsfrågan påverkas om överföring med stöd av AL 12 a § sker eller inte. För att kunna reda ut ansvarsfrågan var det viktigt att försöka förstå vad som skiljer rätten till utrymme från äganderätten.

    Resultatet visar att överföring av fastighetstillbehör med stöd av AL 12 a § förekommit i 17 av de 45 insamlade förrättningsakterna. De fastighetstillbehör som vanligen överförts var framförallt VA-ledningar, men också dagvattenledningar, utomhusbelysning, medieanläggningar i form av kabel-tv, bredband, fiber och centralantenn, samt körytor såsom väg och utfart. Avgörande för om AL 12 a § tillämpas är förrättningslantmätarens inställning till, och kunskap om bestämmelsen. Vad gäller ansvar kring försäkringsfrågan anses anläggningssamfällighetens förvaltningsform av större betydelse än om överföring kommit till stånd eller inte. Rätten till utrymme skiljer sig obetydligt från äganderätten i detta sammanhang, eftersom försäkringsvillkoren utgår från ansvaret för fastighetstillbehöret och inte själva äganderätten. Överföringen av fastighetstillbehöret saknar därför praktisk betydelse. Föreningsförvaltning anses i sammanhanget lämpligare än delägarförvaltning. Valet av förvaltningsform är viktigare ju dyrare fastighetstillbehöret är och ju större nytta det utgör för de i gemensamhetsanläggningen deltagande fastigheterna.   

  • 278.
    Hacklin, Fredrik August
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    A 3G Convergence Strategy for Mobile Business Middleware Solutions: Applications and Implications2001Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Mobile business solutions are one of the most attractive market segments of mobile information services. The third generation of mobile communication systems (3G) will be a significant step forward in the convergence of telecommunications and datacommunications industries. More specifically, the convergence of mobile technologies and the Internet allows compelling possibilities for future applications and solutions. However, most current mobile businesses and mobile application and solution providers are rather contributing to the process of convergence; many current ideas and solutions are based on the restrictions of existing mobile networks combined with Internet-based services. In the future, when mobile networks and the Internet have merged, it will no longer be possible to create revenue with these types of solutions.

    One concrete solution is the mobile middleware concept, bridging the mobile technologies and Internet world. This Master’s thesis studies the middleware concept for providing business applications in the light of 3G, making strategic recommendations to a provider of these kinds of services. A comprehensive discussion about the developments after 3G is introduced. Alternative solutions are presented and some strategic implications are introduced. The implications are motivated by an industry survey, carried out within this project. The topic of over-the-air data synchronization is discussed as an example for interim middleware. Mobile computing file system issues are seen as an interesting opportunity for business applications. The possibility of remote desktop screen access is studied, and measurements proving its feasability for hosted wireless application service provision are made. Emerging mobile Java technologies are discussed as an efficient platform for providing ubiquitous, device independent end-to-end solutions. As one of the recommended strategies, this thesis introduces the concept of hybrid thickness client applications as a feasible solution for migrating from current middleware solutions to an (uncertain) future of native, thick terminal applications, within a scope of two years. Based on this concept, a prototype for a 3G smartphone application was developed as an example. A set of possible strategic scenarios is presented and discussed. This thesis also discusses operator differentiation and business solutions in an all-IP based world.

    3G networks and handset devices will introduce a large number of new applications and business opportunities, but such a change will also introduce new challenges and risks. The migration challenge is being illustrated in the case of Smartner, a mobile middleware solution provider focusing on business applications. As shown by this case, compared to current enabling solutions, a major shift in technologies is seen as needed, in order to maintain long-term success.

  • 279.
    Haeberlein, Christoph
    KTH, Tidigare Institutioner, Teleinformatik. KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Generating and Analysing test pattern for ATM applications1996Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The essence of this Master's Thesis is to describe the way I have generate realistic traffic cases for ATM applications.

    The base is made up by a Verilog program which is intended to communicate with the Switch Port Verilog code by transmitting and receiving ATM cell packets. The generation of cells is made in C code by using a Programming Language Interface provided by Cadence.

    Several kind of isochronic services are described by using parameters in a three state Markovian Modulated Bernoulli Process with binomial distributed burst arrivals (MMBP/D/1-K Model). The model generates bursts which are put in separate input buffers for each source and are later polled by a round robin fashion.

    Some of the parameters given in a previous work have been proven not to be in the allowable area for the probability. This has been noticed but not been further examined in this thesis.

    The performance of the generator is about 240.000 cells per hour on a SUN Sparc Station 5 with 400 video teleconference sources.

  • 280.
    Hagernäs, Patrik
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    5G user satisfaction enabled by FASP: Evaluating the performance of Aspera's FASP2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    With Ericsson’s goal to have optimal user experience at 5G’s 2020 release, it is very important to optimize transport protocols and techniques to manage the increasing amount of data traffic. Additionally, it will be important to manage handovers between very high speed 5G networks and older networks. Today most of the traffic is video on demand and the amount of this kind of traffic is expected to increase. Moreover, the current amount of data traffic will increase by an order of magnitude over the next few years. This thesis focuses on radio access networks and the difficulties they face in delivering high speed data traffic.

    This thesis analyzes one of the most used TCP protocols, CUBIC, as well as a new transport protocol developed by Aspera, called the Fast and Secure Protocol. Aspera’s FASP is a new transport protocol that promises full link utilization. FASP is built upon UDP and uses advanced round trip time measurements and queuing delay to detect the available bandwidth between two communicating hosts.

    This thesis project also provides methods to realize experiments to assess the limitations of transport protocols. These experiments are conducted in an environment that resembles the upcoming 5G radio access network. Results have shown that both delay and packet loss affect TCP more than we expected and that high packet loss is devastating. In contrast, Aspera’s FASP is very resistant to both delay and packet loss. These results and analysis provide a foundation upon which others can build.

  • 281.
    Haggård Ljungquist, Jonas
    KTH, Tidigare Institutioner, Teleinformatik.
    Transport Protocols for IP-traffic over DVB-T1999Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The rapid growing demand for Internet connectivity has created a surge for new techniques that will enable people to connect from any place at any time. The wireless networks of today are limited in range or in bandwidth. In this thesis work DVB-T (Digital Video Broadcast - Terrestrial) has been studied in combination with GSM (Global System for Mobile communications), in order to evaluate how such a system can be used to provide a high bandwidth, long range, data link.

    The commonly used Transmission Control Protocol (TCP) is known to perform very poorly with asymmetric and long delay links. Wireless links usually have bit errors, errors that corrupts packets, and often these bit errors come in bursts and thereby corrupting many packets. More than one lost packet will significantly degrade the TCP performance. In an asymmetric network the link with the smallest bandwidth will set the limit of throughput if any kind of data acknowledgments (Acks) are used. TCP is ACK driven and for large asymmetries the theoretical throughput will depend heavily on the packet-size and the bandwidth of the narrow link. The DVB-T/GSM system is both wireless and highly asymmetric, in raw bandwidth as well as in delay, which makes the use of standard TCP unworkable.

    Many techniques has been studied in order to find a solution to how the transport protocol should be tuned to handle the characteristics of DVB-T and GSM. The solution presented in this work does not set any demands on the host on the Internet, and is fully compatible with existing standards. This system will enable speeds up to 13 times faster than conventional TCP.

  • 282.
    Hagman, Lasse
    KTH, Tidigare Institutioner, Teleinformatik.
    Simulating the Global Positioning and Communication system1995Independent thesis Advanced level (degree of Master (Two Years)), 12 poäng / 18 hpOppgave
    Abstract [en]

    This project mainly consisted of implementing the software for a system simulator, which will be used during development and testing of a navigation and communication equipment. The system is called GP&C (Global Positioning and Communication system) and is primary intended for aviation and maritime applications.

    The GP&C equipment does essentially consist of a GPS-receiver and a radio transceiver, connected to a communication processor. A large number of such units, called GP&C transponders, send information about their positions on a shared radio channel in different time slots. By listening to the radio traffic, every transponder has access to position data of all other units.

    Running the system simulator, an operator defines a number of simulated transponders and specifies which types of messages these shall send. Furthermore the operator declares data for each message and in which time slots the messages will be sent. Given data will be processed and sent out through a connected radio transceiver. The simulator, like the transponders, obtain a precise time base from GPS-satellites via connected GPS-receiver, making system synchronization possible. The system simulator records the radio signals broadcasted by real transponders, hence one can analyse how they react on the simulated transponders radio broadcasts.

  • 283.
    Haider, Maria
    KTH, Skolan för informations- och kommunikationsteknik (ICT). Ericsson A/B.
    Privacy Ensuring SRTP for Cloud Conferencing2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Multimedia conferences held using services provided by clouds owned by third party companies are becoming increasingly popular. While using such services, end users will want to keep their audio/video data private when they pass through the servers situated in the cloud. Application of SRTP (Secure Real-time Transport Protocol) in such use cases fail to provide the desired privacy because it leads to sharing the master keys for encryption and authentication of the media content with the semi trusted media servers of the cloud. As a solution, modifications of SRTP are proposed in this thesis with the result of redesigning the security mechanisms of RTP header extensions and RTCP packets by separating the cryptographic contexts and keying materials for protecting end-to-end sensitive data. A couple of design choices for key management through DTLS-SRTP for Cloud conferencingare also proposed. Moreover, analysis of existing solutions for modifying SRTP packets for cloud conferences have also been carried out in this project. The solutions are found by studying related protocols, understating the problems and analyzing current solutions if there were any. The proposed solutions show different alternatives to solve a specific problem and their tradeoffs in terms of complexity and compatibility with current standards.

  • 284.
    Hallén, John G
    KTH, Tidigare Institutioner, Teleinformatik.
    Test of SSL Security Communication products1999Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This report is a part of my master thesis project (x-jobb) done at Celo Communications AB in Stockholm during the spring of 1999. First part presents the basics of cryptography, certificates and digital signatures – all part of a PKI. This presents the baseline of information to enter the PKI world, with focus on the SSL/TLS protocol. Second part describes tests that I have performed on the CeloCom SSR Server, which is a SSL/TLS Server. The measured performance is presented in figures and graphs and performance related factors discussed.

    The use of Internet has exploded over the last years and have become an important part of many peoples lives. To extend the use, and add value to the services that can be provided on Internet it is necessary to enable secure communication. Without security the use is limited. Public Key Infrastructure (PKI) provides the framework, and SSL/TLS is a part of a PKI that enables secure communication between two peers over Internet. The problem with cryptography is that it is by nature complex, and requires processing power out over the normal power required to perform clear text communication.

  • 285.
    Hamrin, Hamrin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Utveckling av produktprototyp för sortering av hushållsavfall2015Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [en]

    Abstract

    Embedded systems are involved more and more into our daily lives thanks to the concept of the Internet of Things (IoT). An important step in this development is the communication between the systems that been used. The possibilities of sending data in a compressed format based on a protocol standard and use a server with built-in functions, can be a good basis for complex system solutions constructed in Internet of Things (IoT).

    The simple protocol Messages Queue Telemetry Transport (MQTT) is described to be a protocol that minimizes any bottlenecks in the Machine - To - Machine (M2M) communications while it offers a number of implementing security solutions as data encryption, unique user credentials (username and password) And authentication thereof, and three different Quality of Service (QoS) levels since the data is transmitted over TCP / IP. Along with this server solution is examined in this report, the ability to implement the protocol in a real communication between the development board and an Android mobile application, where the data handled by the broker HiveMQ and stored in a MySQL database and then transferred via a web server to the mobile application.

    The purpose of the report is therefore to examine the implementations possibility for MQTT in a real scenario with the broker HiveMQ. Where the project resulted in a complete communications solution that corresponds to the protocol can be implemented as well as a theoretical explanation of the security solutions that can be taken to and how well the protocol can scale in a theoretical example.

    During the work, the development board CC3200 LaunchPad used as target platform.

    Keywords: CC3200 LaunchPad, HiveMQ, Broker, SQL, Android

  • 286.
    Hassan, Ahmad
    et al.
    Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT. Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för fysik och elektroteknik.
    Hoque, Ahsanul
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för fysik och elektroteknik.
    Automated Microwave Antenna Alignment of Base Transceiver Station2011Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    This master’s thesis is intended for the solution of Microwave (MW) link alignment which has several applications in modern communication systems. MW communication is used for point to point links with small wavelength and simultaneously compact antenna dimensions. Assuring the automated alignment of antennas provides a better communication between switching stations and allow its subscribers to communicate ceaselessly. In the first part of the work; effects of downtime on a network are discussed and at later stage a mechanism is investigated which will reduce the downtime. MW antenna used in communication systems is regularly affected by environmental factor and generally by wear and tear of mounts. These factors cause the precisely directed antennas to be perturbed from respective main lobes. Larger antennas with narrow main lobes require more sophisticated designing while smaller antennas have a broader main lobe. An automated antenna alignment that works without human intervention can decrease the down time and ensure a reliable communication between the near end and far end terminals of the Base Transceiver Station (BTS). The focus has been laid on a system that works autonomously and for that LabVIEW design and RCX Robonics Kit is used.  Results are presented to indicate antenna alignment in automatically synchronized manner.

  • 287.
    Hassellöf, Daniel
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Position Determination using multiple wireless interfaces2008Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This Master’s thesis studies different ways of exploiting the signal strength measurements from wireless interfaces for position determination. Difficulties include handling the fluctuating observations and their sensitivity to obstruction. We list important factors to take into account before describing a new system based on location fingerprinting and capable of integrating observations from multiple wireless interfaces.

    Compared to typical fingerprinting solutions, the training time is an order of magnitude shorter, but the location resolution is limited to locations of particular interest. In an office environment, the proposed solution determines the location correctly 80 percent of the time with sufficient precision for being used with context-aware services. In an open space environment, an incorrect location is reported 42 percent of the time.

  • 288.
    Hedberg, Daniel
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Network Processor based Exchange Terminal: Implementation and evaluation2002Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    When communication nodes are connected to different networks, different kinds of Exchange Terminals (ETs) i.e., line card, are used. The different media we consider here have a bit rate between 1.5Mbps to 622Mbps and use protocols such as ATM or IP. In order to minimize the number of different types of ET boards, it is interesting to study the possibility of using Network Processors (NP) to build a generic ET that is able to handle several link layer and network layer protocols and operate at a wide variety of bit rates.

    This report investigates the potential of implementing an ET board using a one-chip or twochip solution using an Intel Network Processor (NP). The design is described in detail including a performance analysis of the different modules (microblocks) used. The report also provides an evaluation of the IXP2400 network processor and contrasts it to some other network processors. The detailed performance evaluation is based on a simulator of the IXP2400, which is part of Intel's Software Development Kit (SDK) version 3.0. In addition, I have investigated: the memory bus bandwidth, memory access latencies, and compared Ccompiler against hand-written microcode. These tests were based on using an application for this ET board, which I have implemented.

    It proved to be difficult to fit all the required functions into a single chip solution. The result is either one must wait for the next generation of this chip or one has to use a two-chip solution. In addition, the software development environment used in the project was only a pre-release, and not all services worked as promised. However, a clear result is that implementing an ET board, supporting the commonly desired functions, using a Network Processor is both feasible and straightforward.

  • 289.
    Hedin, Erik
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Social networks and mobile devices: The next generation mobile phonebook with social networking widgets2008Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Social networking services on the Internet are growing and increasing numbers of people are using these new ways to communicate and share information. Many users are communicating with both friends from outside the service as well as with people they have only been in contact with through a social networking service.

    At the same time mobile phones are becoming more powerful and increasingly offer high speed Internet connectivity. Because of this people expect these social networking services to be available on their mobile device, as well as on their personal computer. Given the capabilities of today’s mobile devices, it is possible to extend the existing phonebook with capabilities to support a variety of social networking services in addition to the existing communication options. By integrating the contacts gained from the social networking service into the mobile phonebook the user can reach these contacts easily.

    Communication in online social networks via a mobile phone is expected to grow in popularity in the near future [1]. Several operators are simplifying access to these networks for their customers by offering different ways to connect to social networks [2][3]. However, access to these networks is often done via web sites or dedicated applications. These solutions are not optimal since browsing the web using a mobile browser can be bothersome and dedicated applications require installation of the application as well as any subsequent updates. Widgets on the other hand solve these problems in a convenient way. They can enable access to a device’s full functionality, just like dedicated applications, and provide a platform for easy development using web technologies. Furthermore, widgets are highly flexible for example, updates do not require reinstallation, and when new social networks become popular new widgets that connect to them can easily be developed and distributed.

    The goal of this thesis is to expand the mobile phonebook with functionality to enable communication on online social networks. To reach this goal I have created a new widget platform, where hybrid widgets run partly in a Java ME application and partly in the mobile web browser. This solution has the potential to significantly enhance the ways we communicate and interact with people. The users are therefore likely to have a larger number of people whom they interact with – rather than a smaller number; hence increasing the overall communication between people.

    This thesis project was performed at Ericsson Research in Kista. Any opinions stated in the thesis are strictly my own. Similarly any technology selections made are my own and do not necessarily reflect any official position(s) of Ericsson.

  • 290.
    Hedin, Magnus
    KTH, Tidigare Institutioner, Teleinformatik.
    Distributed Directory Services1998Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This document analyses Distributed Directory Services and provides an introduction to them; along with an exploration of some of the technical and organizational aspects of such services for companies planning to deploy a directory service for their organization.

    In Lightweight Directory Access Protocol (LDAP) version 3 an extensible security model is defined. It is based on the Simple Authentication and Security Layer (SASL), which allows for integrity and privacy services to be negotiated. Implementing LDAP over Secure Sockets Layers (SSL) enables user authentication, data encryption, and data integrity protection so files cannot be altered after they are transmitted.

    Performance measurement, made as a part of this project, show that a shallow Directory Information Tree (DIT) structure is faster to access that a deeper one. Hence, the structure should be as shallow as possible, but without sacrificing maintainability. To lower the cost of managing or synchronizing multiple directories, organizations should deploy a directory service, which as many applications as possible can share.

    Replication between servers is desirable. It will increase the performance and reliability of the directory service. If a server fails there will be another one which can take over. Regarding replication schemes I have found the multi-master scheme, although more complicated in terms of administration, much better due to the better reliability and performance.

  • 291.
    Hedlund, Henrik
    KTH, Tidigare Institutioner, Teleinformatik.
    A gateway between Jini and Universal Plug and Play2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis project concerns creating a gateway to enable Jini and Universal Plug and Play (UPnP) devices connected to a local area network to communicate (specifically to allow a Jini or UPnP browser to display the existence of a device and allow a user to control the device). The project realized such a gateway and demonstrated the operation of the gateway with several existing Jini and UPnP devices.

    This thesis provides the reader with the necessary background to understand these two different technologies. After the two technologies are introduced they are compared.

    The thesis also makes some prediction that both of these technologies will continue to be used and that both will evolve. One the key problems highlighted for Jini is its lack of a mechanism for devices to get IP addresses. One of the strengths highlighted for UPnP is its use of open standards and its use of XML as a description language for the device.

    The project was performed at Telia Research AB in Nynäshamn. It was a part of a Telia Research AB project called Home Wide Web (HWW). Within HWW different technologies for building the future household IT-infrastructure are developed and evaluated. Two promising technologies in this area are Jini and Universal Plug and Play.

  • 292.
    Hellström, Joakim
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för informations- och kommunikationssystem.
    Utvärdering av nätverkssimulering och enhetsemulering: GNS3 och Packet Tracer2015Independent thesis Basic level (university diploma), 5 poäng / 7,5 hpOppgave
    Abstract [sv]

    Denna rapport tar upp hur ett par olika programvaror, nämligen Packet Tracer och GNS3 kan användas för att simulera verklig utrustning i syftet att använda dessa hos ett företag i labbmiljö för att förbereda en implementation av ny hårdvara samtidigt som kostnaderna kan hållas nere, men också hur dessa programvaror kan användas i studiesyfte och använda som komplement till fysisk utrustning inför laborationer och examinationer i de olika kurserna som Cisco erbjuder. Det är också en utvärdering för att avgöra vilken av programvarorna som är den bästa att använda. En topologi sätts upp, komplett med IP-adressering med relativt vanlig konfiguration för att se hur dessa programvaror hanterar och klarar av dessa konfigurationer. Det visar sig att båda programvarorna presterar bra i de flesta fall, men de avbildningar av IOS som testats i GNS3 saknar stöd för PortSecurity som standard, så Packet Tracer tar titeln. Packet Tracer lämpar sig bäst för grundläggande studier med sina enkla paketspårningar medan GNS3 fungerar bättre för mer avancerade topologier med möjlighet till import av befintlig hårdvara.

    Nyckelord:  Cisco, Packet Tracer, GNS3, Simulering.

  • 293.
    Hemlin Billström, Adam
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Huss, Fabian
    Video Integrity through Blockchain Technology2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The increasing capabilities of today’s smartphones enables users to live stream video directly from their mobile device. One increasing concern regarding videos found online is their authenticity and integrity. From a consumer standpoint, it is very hard to distinguish and discern whether or not a video found on online can be trusted, if it was the original version, or if has been taken out of context. This thesis will investigate a method which tries to apply video integrity to live streamed media.

    The main purpose of this thesis was to design and evaluate a proof of concept prototype which will apply data integrity while simultaneously recording videos through an Android device. Additionally, the prototype has an online verification platform which verifies the integrity of the recorded video. Blockchain is a technology with the inherent ability to store data in a chronological chained link of events: establishing an irrefutable database. Using cryptographic hashes together with blockchain: an Android device can generate cryptographic hashes of the data content from a video recording, and consequently transmit these hashes to a blockchain. The same video is deconstructed in the web client creating hashes that can subsequently be compared with the ones found in the blockchain.

    A resulting prototype system provides some of the desired functions. However, the prototype is limited in that it does not have the ability to sign the hashes produced. It has also been limited in that it does not employ HTTPS for communication, and the verification process needs to be optimized to make it usable for real applications.

  • 294.
    Henningsson, Jon
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Användargränssnitt för iptables2012Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Iptables är en programvara i Linuxsystem som frekvent används för att administrera brandväggsregler. Att lägga till regler med iptables kan vara komplicerat för ovana användare. Målet med detta arbete är att skapa ett grafiskt användargränssnitt för programvaran iptables i Linux, med syftet att ge personer ett sätt att lära sig om brandväggar och främst iptables på ett mer pedagogiskt sätt.

    För att skapa det grafiska gränssnittet har Linuxmiljö använts och programmeringen har skett med Python, Qt och PyQt. Det har resulterat i ett grafiskt gränssnitt som ger användare möjlighet att administrera iptables på ett enklare sätt. Programmet analyserar även regler för att kunna ge användaren information om regler som är aktiva.

  • 295.
    Hjalmarsson, Henrik
    KTH, Tidigare Institutioner, Teleinformatik.
    Mobile Video CommunicationforEmergency Services2000Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Technological advances in the field of mobile telecommunications are changing the world of public safety today. The new technologies have come to attention for emergency services around the world to take advantage of what they have to offer. This thesis work has evaluated three candidate mobile video communication systems for transmitting live video images from the scene of an accident to front and rear command and control centres as well as emergency hospitals. The systems and their associated technologies were evaluated as whether they are suitable for use in emergency services.

    The three systems incorporate transmission over analogue radio link, satellite and GSM networks. All of these technologies were evaluated and their implications on the accident scene as well as the environment’s implications on the equipment were considered. To form a base in the evaluation one test of each of these systems was performed, during emergency services training exercises. At these occasions the full operational systems could be seen in action and its capabilities and limitations could be observed.

    The result of the study was that all three systems are feasible for use in emergency services, but there are differences in mobility, quality and user-friendliness as well as cost for the systems that has to be considered. However, none of the systems could fully conform to the strict requirements set for the systems in the project specification.

  • 296.
    Hjelmér, Johan
    et al.
    KTH, Tidigare Institutioner, Teleinformatik.
    Eriksson, Henrik
    KTH, Tidigare Institutioner, Teleinformatik.
    Content Aware Mobile Email Services1999Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The use and importance of email has increased tremendously over the past few years. Internet users are also becoming increasingly mobile and there has been a recent explosion in the market for small, hand-held Internet connected devices. Email has been identified as a “killer application” for these devices and the race between hardware manufacturers, software houses and service providers to meet the email needs of mobile consumers is on.

    Meanwhile the use of attachments in email messages has increased and these attachments are becoming more complex, thus requiring more bandwidth. They also often contain graphics such as images and video.

    The new small email enabled devices typically have small black and white screens, slow processors and little local storage, i.e. they are not very well suited for downloading and reading email attachments. We therefore propose adding content awareness to email services. By this we mean that email content is adapted to better suit the client before it is downloaded.We have identified two types of adaptions which are applicable: stripping (removing attachments from an email) and thinning (reduction of attachment size).

    We have looked at different ways of adding content awareness to an email service. We have implemented an agent based solution which uses multiple inboxes. We chose to call the solution MMAA (Mobile Mail Adaption Agent). The MMAA system is built around a standard IMAP server, a standard IMAP client and a personal Java agent. We have designed, implemented and evaluated the MMAA from a usability and security point of view. It works well, the main objection is that users tend to get confused by the idea of having more than one inbox.

    We have also examined the underlying email protocols IMAP and SMTP and suggested an addition to the IMAP protocol which would make it easier to implement future content aware email services. The extension adds a command to IMAP4rev1 called ADAPT. The ADAPT command lets clients communicate their characteristics to the server while fetching mail. The server can then content adapt the mail message according to these characteristics before delivering it to the client. The ADAPT extension has resulted in an Internet draft which can be found in Appendix C of this paper.

    When we analysed the ADAPT extension and compared it to the agent based approach we found that the difference in download time is rather small and we have identified some improvements that could be made. Our conclusion is that the ADAPT extension is definetly the best way to add content awareness to a mobile email service.

  • 297.
    Holmlund, Erik
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    A comparative study of two different network basedIP Virtual Private Network solutions2003Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Network based (layer 3) IP VPNs is a growing service and Skanova has a solution today which has received a lot of customer attention. The service is called VPN Flex and offers the customers secure communication between their different offices while supporting different traffic classes with a guaranteed maximum delay, jitter, and packet loss. VPN Flex has been a success so far in terms of the number of customers that have signed up for it in the short time it has been on the market. VPN Flex is realized over an IP network on Skanova's ATM backbone.

    Meanwhile Multi Protocol Label Switching (MPLS) has attracted a lot of attention and is considered to have a lot of nice features; the most import being the ability to provide layer 2 and layer 3 IP VPNs. The MPLS solution for providing network based layer 3 IP VPNs is described in RFC 2547, also called BGP/MPLS VPNs. It has become the de-facto standard for providing network based layer 3 IP VPNs. Skanova's VPN Flex service is provided by a partly Nortel proprietary solution using IP tunneling instead of MPLS tunneling which is used in RFC 2547.

    The purpose of this paper is to evaluate which network (i.e. link layer technology; specifically a frame based or a cell based media) and which network based IP VPN solution is most suitable to provide a network based layer 3 IP VPN service that supports different traffic classes so that Skanova's customers can use this VPN service to send best effort traffic, mission critical applications, IP Telephony, and Video Conferencing services between their different offices using a single layer 3 VPN solution.

    In my evaluation I have looked at the technology behind the VPN solution, the ability to provide delay, jitter, and packet loss guarantees as well as what it costs to produce the service along with the security and expected reliability. The purpose of having a master’s thesis student looking at this problem is that I would be objective and not have any predetermined conclusions.

    The result of the study is that the two different network based VPN solutions are not different with regard to the service they provide for the customers. However, there are some differences that affect the operator deploying and running the service. RFC 2547 is a more flexible solution with less manual configuration and better support for Inter-AS VPNs. It is possible to realize an RFC 2547 solution in either an ATM network or an IP network and the services will be implemented in much the same way. Both solutions could use Label Distribution Protocol (LDP) signaling and EXP Inferred PHB Scheduling Class LSPs (ELSPs), realizing traffic classes using the MPLS EXP bits. Which network to base the solution on, is a matter of QoS support, costs, and security. The ATM network today has better QoS support (such as more transmission queues and efficient schedulers). However, at the link speeds used in today’s backbones the fixed size cell of ATM is not a reason to use the ATM network instead of a frame based IP network.

    The cost of using Packet Over Sonet (POS) and ATM is the same. However, using Ethernet the port cost is less than half of either POS or ATM, which favors using an IP network in the A comparative study of two different network based IP Virtual Private Network solutions future. The security of a network based layer 3 IP VPN is mostly in the hands of the operator configuring the service and the network. Thus with regard to security, I do not believe there is a difference when realizing the network based IP VPN service in a public or private IP network. However, a network based IP VPN realized in a public IP network might pose a sales problem because many customers are worried about the security and availability of such a network.

    RFC 2547 and MPLS seem to be the way to go in the future, but my recommendation is to make the transition slowly thereby minimizing Capital Expenditures (CAPEX). This is especially true since the current network based IP VPN service has been so well received. Whether Skanova should introduce MPLS and RFC 2547 in the IP network or the ATM network is very much dependent on their future strategy. I believe that both the IP network and the ATM network can support a service such as VPN Flex. Also, the way that MPLS will be used with regard to the VPN Flex service is the same.

  • 298.
    Holmstedt, Christoffer
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Model-checked Space Plug-and-Play Architecture Local Subnet Adaptation implemented in Ada with Ravenscar restrictions2014Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Space Plug-and-Play Architecture (SPA) is a set of standards to make it easier to build small satellites. Focus is put on improving the integration phase andthe time consuming validation and verification process by introducing plug-and-play functionality. From mission call-up to operational satellite it should only take six days.

    A SPA network consists of several different types of subnets with differentpros and cons. For each processing node there must be one Local Subnet Manager (SM-L). The SM-L can communicate over different communication protocols depending on how the respective local subnet is set up, one option is UDP/IP.

    In this thesis Ada Protected Objects is presented as a viable option for inter-process communication instead of UDP/IP in a SPA network. This thesis presents the initial work towards a SPA Local Subnet Adaptation that builds onlanguage constructs in Ada such as Ada Tasks and Protected Objects. The system design and implementation is verified deadlock free with UPPAAL but showsindications of livelock possibilities. The severity of these livelocksituations is discussed in the conclusion.

  • 299.
    Holmsten, Maria
    KTH, Tidigare Institutioner, Teleinformatik.
    Mobile IP: Mobile communication for a mobile user1999Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In a near future, computer users will want to be able to move around in a network and to log on to the nearest computer. Users will want to work and interact in an environment according to their own preferences, just as in their home network. This thesis proposes an extension of the terminal mobility supported by mobile IP [6] with user mobility support.

    The theoretical background in the thesis focuses on, after distinguishing between different types of mobility to: (1) present Mobile IP, (2) introduce user mobility and also to discuss some requirements, and (3) give a general description of agents.

    It is suggested that a User Agent (UA) represents a single user in the network and is responsible for his/her mobility. A user is registered at zero or more IP nodes. In order to allow several users to share the same IP node, a Remote User Agent (RUA) is required for each user on his/her IP node. The RUA will be created remotely at the specific mobile node, by the user’s UA.

    A User Profile contains information and preferences related to a user. Also, through its profile, the owner of a terminal can protect it from being at registered by other users. The UA has a User Registration Container which is composed of a User Profile and a User Registration Table, containing information about each of the user’s current registrations.

    A user registers at a mobile node through a User Registration Interface which is accessed through a Web browser after the necessary identification and authentication procedures have been completed.

  • 300.
    Hossain, Md. Iqbal
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Hossain, Md. Iqbal
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS Lab).
    Dynamic scaling of a web-based application in a Cloud Architecture2014Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    With the constant growth of internet applications, such as social networks, online media, various online communities, and mobile applications, website user traffic has grown, is very dynamic, and is oftentimes unpredictable. These unpredictable natures of the traffic have led to many new and unique challenges which must be addressed by solution architects, application developers, and technology researchers. All of these actors must continually innovate to create new attractive application and new system architectures to support the users of these new applications. In addition, increased traffic increases the demands for resources, while users demand even faster response times, despite the ever-growing datasets underlying many of these new applications. Several concepts and best practices have been introduced to build highly scalable applications by exploiting cloud computing. As no one who expect to be or remain a leader in business today can afford to ignore cloud computing.

    Cloud computing has emerged as a platform upon which innovation, flexibility, availability, and faster time-to-market can be supported by new small and medium sized enterprises. Cloud computing is enabling these businesses to create massively scalable applications, some of which handle tens of millions of active users daily. This thesis concerns the design, implementation, demonstration, and evaluation of a highly scalable cloud based architectures designed for high performance and rapid evolution for new businesses, such as Ifoodbag AB, in order to meet the requirement for their web based application. This thesis examines how to scale resources both up and down dynamically, since there is no reason to allocate more or less resources than actually needed. Apart from implementing and testing the proposed design, this thesis presents several guidelines, best practices and recommendations for optimizing auto scaling process including cost analysis. Test results and analysis presented in this thesis, clearly shows the proposed architecture model is strongly capable of supporting high demand applications, provides greater flexibility and enables rapid market share growth for new businesses, without their need to investing in an expensive infrastructure.

3456789 251 - 300 of 832
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf