Optimizing task priority assignments is a well-researched area in the context of hard real-time systems, where the goal in the majority of cases is to produce a priority assignment that results in a schedulable task set. The problem has also been considered, albeit not to the same extent, in the soft real-time context where quality of service metrics determine the overall performance of systems. Previous research on the problem in the soft real-time context often resorts to some analytical approach, with the drawback of having to put relatively strict constraints on the system models to avoid excessively complex analysis computations. As a consequence, many attributes of a real system have to be omitted, and features such as multi-processor hardware platforms might make the analytical approach unfeasible due to complexity issues. In this thesis we took a different approach to the problem and used discrete event simulation to drive the priority assignment optimization process, which enabled more complex system models at the cost of increased objective function evaluation times. A latency-related quality of service metric was used as the objective function in a tabu search based optimization heuristic. Improvements were observed in both simulation and in the real system that was modeled. The results show that the model successfully captured key attributes of the modeled system, and that the discrete event simulation approach is a viable option when the goal is to improve or determine the quality of service of a soft real-time application.

This thesis describes the process of modeling and analysis of corporate communication through chat and telephone with data taken from the Briteback enterprise communication application. Phone communication is measured by the number and duration of calls, and chat communication by the minimum number of messages sent from one person to another. The measurements are used to calculate a communication score, different methods are tested and a version using principal component analysis is chosen. Different centrality measurements are performed on the graph model that and each tested measure is found to be useful in some way; eigenvector centrality fits the data best, PageRank is easy to understand and can be adapted for dirfferent situations, and betweenness centrality points out users in critical positions in the communication graphs. Personalized PageRank ’focused’ on users or a group of users is tested and shows potential to be of use for social network service companies in many different ways such as when ordering search results or when suggesting new members to a chat channel.

Critical infrastructure provides us with the most important parts of modern society, electricity, water and transport. To increase efficiency and to meet new demands from the customer remote monitoring and control of the systems is necessary. This opens new ways for an attacker to reach the Supervisory Control And Data Acquisition (SCADA) systems that control and monitors the physical processes involved. This also increases the need for security features specially designed for these settings. Anomaly-based detection is a technique suitable for the more deterministic SCADA systems. This thesis uses a combination of two techniques to detect anomalies. The first technique is an automatic whitelist that learns the behavior of the network flows. The second technique utilizes the differences in arrival times of the network packets. A prototype anomaly detector has been developed in Bro. To analyze the IEC 60870-5-104 protocol a new parser for Bro was also developed. The resulting anomaly detector was able to achieve a high detection rate for three of the four different types of attacks evaluated. The studied methods of detection are promising when used in a highly deterministic setting, such as a SCADA system.

The security in home networks is a growing concern, not in the least due to the increase in connected devices with the Internet of Things (IoT). Different types of Intrusion Detection Systems (IDS’s) exists with various system requirements. This thesis will research and compare two of these, Bro and Snort IDS in order to determine their functionality in a low resource environment such as a Raspberry Pi. In order to measure functionality and performance, several experiments have been conducted such as penetration testing and thorough installation and configuration experiments. / <p>Nationell ämneskategori - osäker på om det är rätt</p>

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Companies today often have a variety of applications used in the daily work. The problem that companies face with these applications is that they often are brought in to deal with a specific task, and they are often brought in at different times by different third-party developers. This results in the applications being independent units and integrates poor with each other, making work and maintenance with the applications inefficient. To improve efficiency the applications need better integration with each other. Better integration can be achieved by either replacing the current applications with a new software or develop a software that helps the applications communicate. This project covers the development of the later, an API to improve the efficiency at Volvo Construction Equipment in Braa ̊s. The API is developed with the Enterprise Service Bus (ESB) as inspiration. The purpose of the ESB is to act as a middleware for the applications. Due to time limitations for the project integration between the applications wasn’t achieved. Instead, the focus was set on improving one of the moments in the work process at Volvo, that is verifying information between applications. The verification is today done manually which makes it time-consuming and this is the API set out to deal with. The API results in a reduction and improvement regarding the verification. The API still needs a manual input of data from the applications, but the API has automated the verification of the information between the applications resulting in hours of reduced work for the staff at Volvo.

Purpose – The purpose of this thesis was to identify and evaluate different filtering algorithms for raw Received Signal Strength Indication (RSSI) values in an indoor positioning system. The purpose was also to examine how the positioning accuracy is affected depending on which filter that was applied to an indoor positioning system based on Bluetooth Low Energy (BLE) 5. Method – To identify and evaluate the filtering algorithms a literature study was performed, where databases such as Primo, Google Scholar, Digitala Vetenskapliga Arkivet among others were used to collect data. To examine how the positioning accuracy is affected by the filtering algorithms, an experimental study was performed. A one-dimensional indoor positioning system was designed were a Blue Gecko BGM111 Bluetooth Low Energy Model with BLE 5 was programed to read the RSSI values from a connection with an iPhone 8. The RSSI values were sent via a UART to an external computer which stored these as a text file. All the filtering algorithms processed the same text file to reassure comparable conditions. The results from the different filtering algorithms were examined in two steps. The first step was to decide if the filtering of the distance values or the filtering of the RSSI values resulted in the highest positioning accuracy. The second step was to compare the results to decide which of the filtering algorithms that gave the highest positioning accuracy. The examination resulted in an observed hypothesis created by the authors, that was validated by conducting a single tailed hypothesis test with a significance level of 0,01. By conducting the tests in three different environments, an assurance was created that the same phenomenon was in place in all environments. The experimental study took place in the following environments: harsh office environment, calm office environment and open environment. Findings – The results from the literature study showed that the Kalman filter, Feedback filter, Gauss filter, Moving Median filter, Moving Mean filter and Particle filter are the most frequently mentioned filtering algorithms in the positioning context. The results from the experimental study showed that the Kalman filter was the filtering algorithm with the highest positioning accuracy. The results also showed that filtering on the RSSI values before they were transformed into distance was an improvement compared to filtering on the distance, after the transformation of the RSSI values. Implications – The results from this thesis will be beneficial for ROL Ergo AB in their upcoming implementation of an indoor positioning system. After a conducted examination of existing work within the field, the authors found a lack of studies that compare positioning accuracy on more than 3 filtering algorithms and with a usage of the latest version of BLE, namely version 5. This shows that the results from this thesis could be of great use for developers of positioning systems based on BLE. Limitations – The time spent realizing this thesis did not allow for a full and exhaustive evaluation of the great number of filtering algorithms that are available. Therefore, only a few filtering algorithms were selected to be examined and tested, which was done by what the authors considered to be a frequent mentioned filtering algorithm in other positioning systems and that was implementable within the timeframe of this thesis. This thesis experimental study only used BLE 5 as communication mean and therefore does not contain a comparison of positioning accuracy between BLE 5 and earlier versions of BLE. Keywords – RSSI, BLE 5, filtering algorithm, positioning accuracy. / Syfte – Syftet med detta examensarbete var att identifiera och utvärdera olika filtreringsalgoritmer för råa RSSI-värden i ett inomhuspositioneringssystem. Syftet var även att undersöka hur positioneringsnoggrannheten påverkas beroende på vilket filter som används, hos ett inomhuspositioneringssystem baserat på Bluetooth Low Energy (BLE) 5. Metod – För att identifiera och utvärdera de olika filtreringsalgoritmerna genomfördes en litteraturstudie där databaser som Primo, Google Scholar, Digitala Vetenskapliga Arkivet med flera använts för att samla in data. För att undersöka hur positioneringsnoggrannheten påverkas av filtreringsalgoritmerna har en experimentell studie genomförts. Ett endimensionellt inomhuspositioneringssystem har konstruerats där en Blue Gecko BGM111 Bluetooth Low Energy Module med BLE 5 programmerats för att läsa RSSI-värdena i uppkopplingen med en iPhone 8. RSSI-värdena skickades via en UART över till en extern dator som lagrade dessa i en textfil. Samtliga filtreringsalgoritmer bearbetade samma textfil för att säkerställa jämförbara förutsättningar. Resultaten från de olika filtreringsalgoritmerna har granskats i två steg. Det första steget var att bestämma om filtrering på avståndsvärden eller om filtrering på RSSI-värden resulterar i bäst positioneringsnoggrannhet. Det andra steget var att jämföra resultaten för att avgöra vilken av filtreringsalgoritmerna som gav högst positioneringsnoggrannhet. Granskningen resulterade i att skribenterna skapade en observerad hypotes, vilken bekräftades genom att genomföra ett ensidigt hypotestest med en signifikansnivå på 0,01. Genom att genomföra testerna i tre miljöer, säkerställs att samma fenomen återupprepades i samtliga miljöer. Miljöerna där den experimentella studien genomfördes var tuff kontorsmiljö, lugn kontorsmiljö och öppen miljö. Resultat – Resultaten från litteraturstudien visade på att Kalmanfiltret, Feedbackfiltret, Gaussfiltret, Glidande Medianfiltret, Glidande Medelvärdesfiltret och Partikelfiltret är de oftast förekommande filtreringsalgoritmerna i positioneringssammanhang. Resultaten från den experimentella studien visade på att Kalmanfiltret var den filtreringsalgoritm som hade högst positioneringsnoggrannhet. Resultaten visade även på att filtrering på RSSI-värdena innan de omvandlas till avstånd medförde en förbättring i positioneringsnoggrannheten jämfört med då filtreringen skedde på de uppmätta avstånden, efter omvandlingen av RSSI-värdena. Implikationer – Resultatet från detta examensarbete kommer vara till nytta för ROL Ergo AB i deras framtida implementering av ett inomhuspositioneringssystem. Efter genomförd granskning av tidigare arbeten inom området har skribenterna funnit en avsaknad av studier som jämför positioneringsnoggrannheten hos fler än tre filter och med ett användande av den senaste versionen av BLE, nämligen version 5. Detta indikerar att resultatet från detta examensarbetet kan vara till nytta för utvecklare av positioneringssystem baserat på BLE. Begränsningar – Tiden som var avsatt för examensarbetet tillät inte en fullständig och uttömmande utvärdering av det stora antalet filtreringsalgoritmer som finns tillgängliga. Därför valdes endast ett fåtal filtreringsalgoritmer att undersökas och testas, vilket har skett utifrån vad författarna ansett vara vanligt förekommande filter hos andra system och som var implementerbara inom tidsramen för examensarbetet. Examensarbetets experimentella studie använde endast BLE 5 som kommunikationsmedel och innehåller därför inte en jämförelse av positioneringsnoggrannheten mellan BLE 5 och tidigare versioner av BLE. Nyckelord – RSSI, BLE 5, filtreringsalgoritm, positioneringsnoggrannhet.

Many organizations are moving towards agile software development and practices such as continuous integration. Being significantly different from traditional development, agile development has unique new challenges to be dealt with. This report is exploring challenges that large-scale organizations adopting continuous integration are experiencing related to their integration process. Challenges that are focused on are those that relate to understanding information about what the continuous integration system does. Two types of challenges were found: those that call for a need of understanding information and those that hinders information from being used. The report also suggests how visualizations can be used to help solving the former of the two.

Denna rapport behandlar det kandidatarbete som projektgruppen SurVive utfört under vårterminen 2017 vid Linköpings universitet. Arbetet gick ut på att i forskningssyfte, konstruera en virtuell miljö för studenter att träna på krävande situationer. Rapporten syftar att diskutera och analysera både virtuell verklighets applicerbarhet på prestationsförbättring samt utvecklingen av den virtuella miljön. Systemet som har utvecklats ska ge en säker och trygg miljö för användaren att praktisera sin presentation. Vidare kommer relevant användardata illustreras på en hemsida för att tillhandahålla återkoppling på framförandet. Huruvida det utvecklade systemet egentligen bidrar till prestationsförbättring, kräver ytterligare forskning och användning. / This report processes the software development project created by the project group SurVive during the spring semester of 2017 at Linköping University. The project involved in the purpose of research, construct a virtual environment in order to allow students to practice demanding situations. The report aims to discuss and analyze virtual realitys applicability on performance enhancement and the development of the virtual environment. The system that has been developed will provide a safe and secure environment for the users to practice their presentations. In addition, relevant user data will be illustrated on a website to provide feedback on their performances. Whether the developed system really contributes to enhanced performance, requires further research.

Ericsson is a global provider of telecommunications systems equipment and related services for mobile and fixed network operators.  3Gsim is a tool used by Ericsson in tests of the 3G RNC node. In order to validate the tests, statistics are constantly gathered within 3Gsim and users can use telnet to access the statistics using some system specific 3Gsim commands. The statistics can be retrieved but is unstructured for the human eye and needs parsing and arranging to be readable.  The statistics handler that is implemented during this thesis provides a possibility for users of 3Gsim to present information that favors their personal interest. The implementation can produce one prototype output document which contains the most common statistics needed by the 3Gsim user. A main focus of this final thesis has been to simplify content and format control for the user as much as possible. Presenting and structuring information now comes down to simple text editing and rid the user of the time consuming work of updating and recompiling the entire application. Earlier, scripts written in Perl, an iterative oriented language, were used for presenting the statistics. These scripts were often difficult to comprehend since there were many different authors with inadequate experience and knowledge. The new statistics handler has been written in Java, a high-level object-oriented language which should better suite the users and developers of 3Gsim.