Massive deployment of diverse ultra-low power wireless devices necessitates the rapid development of communication protocols. Software Defined Radio (SDR) provides a flexible platform for deploying and evaluating real-world performance of these protocols. But SDR platform based communication systems suffer from high and unpredictable delays. There is a lack of comprehensive understanding of the characteristics of the delays experienced by these systems for new SDR platforms like LimeSDR. This knowledge gap needs to be filled in order to reduce these delays and better design protocols which can take advantage of these platforms. We design a GNU Radio based IEEE 802.15.4 experimental setup, where the data path is time-stamped at various points of interest to get a comprehensive understanding of the characteristics of the delays. Our analysis shows GNU Radio processing and LimeSDR buffering delay are the major delays in these data paths. We try to decrease the LimeSDR buffering delay by decreasing the USB transfer size but it comes at the cost of increased processing overhead. The USB transfer packet size is modified to investigate which USB transfer size provides the best balance between buffering delay and the processing overhead across two different host computers. Our experiments show that for the best-measured configuration the mean and jitter of latency decreases by 37% and 40% respectively for the host computer with higher processing resources. We also show that the throughput is not affected by these modifications. Higher processing resources help in handling higher processing overhead and can better reduce the buffering delay. / Stora installationer av heterogena extremt energisnåla trådlösa enheter ställer krav på snabb utveckling av kommunikationsprotokoll. Mjukvarubaserad radio (Software Defined Radio, SDR) tillhandahåller en flexibel plattform för att installera och utvärdera faktisk prestanda för dessa protokoll. Men SDR-baserade system har problem med stora och oförutsägbara fördröjningar. Verklig förståelse av hur dessa fördröjningar beter sig i nya plattform som LimeSDR saknas. Dessa kunskapsbrister behöver överbryggas för att kunna minska fördröjningarna och för att mer framgångsrikt kunna designa protokoll som drar nytta av de nya plattformarna. Vi skapar en försöksuppställning för IEEE 802.15.4 baserad på GNU Radio. Data som passerar systemet tidsstämplas för att ge underlag till att förstå fördröjningarnas egenskaper. Vår analys visar att fördröjningarna främst kommer från processande i GNU-radion och buffertider för LimeSDR. Vi försöker minska buffertiderna för LimeSDR genom att minska paketstorleken för USB-överföring, men det kommer till priset av ökade bearbetningskostnader. Paketstorleken för USB-överföring modifieras för att på två olika testdatorer undersöka den bästa balansen mellan buffertider och bearbetningskostnader. Våra experiment visar att för att den mest noggrant undersökta försöksuppställningen så minskar medelvärdet och jittret för fördröjningarna med 37% och 40% för testdatorn med mest beräkningskraft. Vi visar också att genomströmningen inte påverkas av dessa ändringar. Med mer beräkningskraft kan de ökade bearbetningskostnader hanteras, och buffertiderna kan förkortas mer effektivt.

Upgrading or migrating a build system can be a daunting task. Complete build system migration requires significant effort. To make the process more effective, we automated the first steps of migration, and attempted to analyze the new build results to find anomalies. Our findings show promise for automation as a first step of migration, and we see that automated evaluation could have some potential.

<p>Studien behandlar ämnet fri programvara utifrån ett diskursanalytiskt perspektiv. Texter och tal av Richard M.</p><p>Stallman, grundaren av Free Software Foundation (FSF), ligger i fokus för studien. FSF är en rörelse som har i</p><p>syfte att göra och kämpa för fri programvara. Detta innebär uttryckligen en kritik mot programvara som är ofri</p><p>eller proprietär. Studien visar på tre olika diskurser som är betydelsefulla för fri programvara; frihetsdiskursen,</p><p>maktdiskursen och etikdiskursen. Det förs även en mer teoretisk kopplad diskussion där texternas relateras till</p><p>teorier om hackeretik, frihet och mänskliga rättigheter.</p>

With the development of powerful computational resources such as Digital Signal Processors and Field Programmable Gate Arrays, It has become possible to utilize many radio functions via software. This is the main concept of an up-and-coming technology of Software Defined Radio. In the Thesis, a number of platforms for implementation of Software Defined Radio has been evaluated. Platform that proved to be most suitable for the project was Ettus’ USRP N210. Using the platform, implementation of 802.15.4 Zigbee’s physical layer was done, where experiments whose outputs can later be used to compare performance with respect to "hardware radios" were performed. / Med utvecklingen av enheter med kraftfulla beräkningsegenskaper som “Digital Signal Processors” och “Field Programmable Gate Arrays” har det blivit möjligt att implementera flera radiofunktioner i mjukvara. Det är huvudkonceptet i den uppåtgående teknologin mjukvaru definierad radio.I det här examensarbetet har ett flertal plattformar för mjukvaru definierad radioutvärderats. Plattformen som visade sig vara mest lämplig för projektet var Ettus USRP N210. En implementation av IEEE 802.15.4 Zigbees fysiska lager har realiserats till plattformen. Experiment, vars utdata senare kan användas för att jämföra prestanda mellan mjukvaru definierad radio och hårdvaru baserad radio, har även utförts. / TESLA - Time-critical and Safe wireLess Automation communication / GAUSS - Guaranteed Automation communication Under Severe disturbanceS

<p>Arguably, the Schumpeterian ideology of “creative destruction” saying that eventually even the most secure monopoly will be destroyed by a new technology, a new idea, or a shift in tastes could be applied to open source software. Currently, the proprietary software holds a strong position in the software market. Nevertheless, one could see a surge in articles and acceptance among organisations concerning open source software.</p><p>Proprietary software companies like Microsoft are still gaining ground within the Swedish municipalities. Although one get the impression that municipalities generally are positive toward open source software, the decision-making process often results in choosing a proprietary software alternative. However, one could question which are the underlying factors and to what extent are these factors affecting the decision-making process of municipalities integrating or migrating into open source software?</p><p>In order to study this phenomenon, we chose a quantitative approach using a questionnaire as the tool for data gathering. The sample consisted of 100 randomly selected municipalities. A pre study was made through an interview in order to strengthen the accuracy of the questionnaire which later on was sent out to the IT manager at each municipality in the sample.</p><p>The organisational-, environmental-, user- and system level are four main factors affecting the decision-making process concerning open source software. Among these, the organisational factor was the only one which had a significant negative impact on the decision-making process concerning open source software. The importance of being able to integrate different software increases the need for compatibility which, according to the IT managers, is facilitated using a standardized software environment offered by for example Microsoft.</p>

<p>Debugging applications that are running in embedded systems is becoming harder and harder due to the growing complexity of the systems. This is especially true for embedded systems that are developed for the automotive market.</p><p>To aid the debugging there are tools called debuggers. Historically, debuggers have been implemented by using a debug port to connect a software debugger running at the developer machine to dedicated on-chip debugging hardware. The problem with this approach is that it is expensive and that it is not possible to use it if the debug port on the system is not available.Therefore there is a demand for user-friendly debuggers that are not as expensive and require no extra hardware.</p><p>This report presents alternatives to debugging embedded systems. From these alternatives a completely software based debugger solution called monitor-based debugging is selected and acts as a foundation for an implementation that is described in the report. The implementation uses GNU Debugger (GDB) and its remote debugging capabilities to perform debugging.</p><p>The implemented debugger is evaluated by using it to debug applications that are running in a powertrain control unit in a modern truck. It is also compared to two commercial hardware based debuggers. In the evaluation it is found that the debugger functionalities and user-friendliness are on par with the commercial alternatives, but that it lacks some in its non-intrusive capabilities when comparing it with the high-end alternatives on the market.</p>

Radio Frequency IDentification (RFID) is a contactless, automatic identification wireless technology primarily used for identifying and tracking of objects, goods and humans. RFID is not only limited to identification and tracking applications. This proliferating wireless technology has been deployed in numerous securities sensitive applications e.g. access control, e-passports, contactless payments, driver license, transport ticking and health cards. RFID inherits all the security and privacy problems that are related to wireless technology and in addition to those that are specific to RFID systems. The security and privacy protection schemes proposed in literature for wireless devices are mostly secured through symmetric/asymmetric keys encryption/decryption and hash functions. The security of all these cryptographic algorithms depends on computationally complex problems that are hard to compute using available resources. However, these algorithms require cryptographic operations on RFID tags which contradict the low cost demand of RFID tags. Due to limited number of logic gates in tags, i.e., 5K-10K, these methods are not practical. Much research effort has done in attempt to solve consumer's privacy and security problem. Solutions that prevent clandestine inventory are mostly application layer techniques. To solve this problem, a new RFID physical layer scheme has been proposed namely Direct Sequence Backscatter Encryption (DSB Enc). The proposed scheme uses level generator to produce different levels before transmitting the signal to the tag. The tag response to the signal sent by the reader using backscatter communications on the same signal which looks random to the eavesdropper. Therefore eavesdropper cannot extract the information from reader to tag and tag to reader communication using passive eavesdropping. As reader knows the different generated levels added to the carrier signal, it can remove the levels and retrieve the tag's messages. We proposed a lightweight, low-cost and practically secure physical layer security to the RFID system, for a supply chain processing application, without increasing the computational power and tag's cost. The proposed scheme was validated by simulations on GNU Radio and experimentation using SDR and a WISP tag. Our implementation and experimental results validate that DSB Enc is secure against passive eavesdropping, replay and relay attacks. It provides better results in the presence of AWGN channel.

Studien behandlar ämnet fri programvara utifrån ett diskursanalytiskt perspektiv. Texter och tal av Richard M. Stallman, grundaren av Free Software Foundation (FSF), ligger i fokus för studien. FSF är en rörelse som har i syfte att göra och kämpa för fri programvara. Detta innebär uttryckligen en kritik mot programvara som är ofri eller proprietär. Studien visar på tre olika diskurser som är betydelsefulla för fri programvara; frihetsdiskursen, maktdiskursen och etikdiskursen. Det förs även en mer teoretisk kopplad diskussion där texternas relateras till teorier om hackeretik, frihet och mänskliga rättigheter.

Debugging applications that are running in embedded systems is becoming harder and harder due to the growing complexity of the systems. This is especially true for embedded systems that are developed for the automotive market. To aid the debugging there are tools called debuggers. Historically, debuggers have been implemented by using a debug port to connect a software debugger running at the developer machine to dedicated on-chip debugging hardware. The problem with this approach is that it is expensive and that it is not possible to use it if the debug port on the system is not available.Therefore there is a demand for user-friendly debuggers that are not as expensive and require no extra hardware. This report presents alternatives to debugging embedded systems. From these alternatives a completely software based debugger solution called monitor-based debugging is selected and acts as a foundation for an implementation that is described in the report. The implementation uses GNU Debugger (GDB) and its remote debugging capabilities to perform debugging. The implemented debugger is evaluated by using it to debug applications that are running in a powertrain control unit in a modern truck. It is also compared to two commercial hardware based debuggers. In the evaluation it is found that the debugger functionalities and user-friendliness are on par with the commercial alternatives, but that it lacks some in its non-intrusive capabilities when comparing it with the high-end alternatives on the market.

This thesis investigates the design and implementation of turbo codes over the GNU radio. The turbo codes is a class of iterative channel codes which demonstrates strong capability for error correction. A software defined radio (SDR) is a communication system which can implement different modulation schemes and tune to any frequency band by means of software that can control the programmable hardware. SDR utilizes the general purpose computer to perform certain signal processing techniques. We implement a turbo coding system using the Universal Software Radio Peripheral (USRP), a widely used SDR platform from Ettus. Detail configuration and performance comparison are also provided in this research.