This thesis is concerned with exploring methods for making computing systems more resilient to problems in the network communication, both in the setting of existing infrastructure but also in the case where no infrastructure is available. Specifically, we target a situation called network partitions which means that a computer or device network is split in two or more parts that cannot communicate with each other. The first of the two tracks in the thesis is concerned with upholding system availability during a network partition even when there are integrity constraints on data. This means that the system will optimistically accept requests since it is impossible to coordinate nodes that have no means of communicating during finite intervals; thus requiring a reconciliation process to take place once the network is healed. We provide several different algorithms for reconciling divergent states of the nodes, one of which is able to allow the system to continue accepting operations during the reconciliation phase as opposed to having to stop all invocations.  The algorithms are evaluated analytically, proving correctness and the conditions for termination.  The performance of the algorithms has been analysed using simulations and as a middleware plugin in an emulated setting. The second track considers more extreme conditions where the network is partitioned by its nature. The nodes move around in an area and opportunistically exchange messages with nodes that they meet. This as a model of the situation in a disaster area where the telecommunication networks are disabled. This scenario poses a number of challenges where protocols need to be both partition-tolerant and energy-efficient to handle node mobility, while still providing good delivery and latency properties. We analyse worst-case latency for message dissemination in such intermittently connected networks. Since the analysis is highly dependent on the mobility of the nodes, we provide a model for characterising connectivity of dynamic networks. This model captures in an abstract way how fast a protocol can spread a message in such a setting. We show how this model can be derived analytically as well as from actual trace files. Finally, we introduce a manycast protocol suited for disaster area networks. This protocol has been evaluated using simulations which shows that it provides very good performance under the circumstances, and it has been implemented as a proof-of-concept on real hardware.

This thesis contributes to three research areas in software security, namely security requirements and intrusion prevention via static analysis and runtime detection. We have investigated current practice in security requirements by doing a field study of eleven requirement specifications on IT systems. The conclusion is that security requirements are poorly specified due to three things:  inconsistency in the selection of requirements, inconsistency in level of detail, and almost no requirements on standard security solutions. A follow-up interview study addressed the reasons for the inconsistencies and the impact of poor security requirements. It shows that the projects had relied heavily on in-house security competence and that mature producers of software compensate for poor requirements in general but not in the case of security and privacy requirements specific to the customer domain. Further, we have investigated the effectiveness of five publicly available static analysis tools for security. The test results show high rates of false positives for the tools building on lexical analysis and low rates of true positives for the tools building on syntactical and semantical analysis. As a first step toward a more effective and generic solution we propose decorated dependence graphs as a way of modeling and pattern matching security properties of code. The models can be used to characterize both good and bad programming practice as well as visually explain code properties to programmers. We have implemented a prototype tool that demonstrates how such models can be used to detect integer input validation flaws. Finally, we investigated the effectiveness of publicly available tools for runtime prevention of buffer overflow attacks. Our initial comparison showed that the best tool as of 2003 was effective against only 50 % of the attacks and there were six attack forms which none of the tools could handle. A follow-up study includes the release of a buffer overflow testbed which covers 850 attack forms. Our evaluation results show that the most popular, publicly available countermeasures cannot prevent all of these buffer overflow attack forms.

Syftet med denna undersökning är att ta fram en taxonomi för databashanteringssystem (DBMS) som kan förenkla valet av DBMS, då det kan vara en lång och komplicerad process. Taxonomin klassificerar kriterier hos DBMS som anses viktiga i en litteraturstudie av flertalet artiklar. Arbetet visar även på en strukturerad process för att gå från krav till val av databashanterare i form av ett poängsystem som använder sig av taxonomin och DBMS rangordning på olika kriterier. Valprocessen tar ställning till de val och krav som användaren lämnat och slutligen tilldelas denne ett förslag, utan att kräva tid och avancerade kunskaper. / The purpose of this study is to develop a taxonomy for database management systems (DBMS) that can simplify the choice of DBMS, when this usually can be a long and complicated process. The taxonomy classifies criteria of DBMS that are considered important in the literature of several articles. The work also shows a structured process to go from requirements to the choice of the DBMS in form of a score based system that uses the taxonomy and the management system’s ranking on different criteria. User choices and other mandatory information is taken into consideration by the process to represent the most suitable DBMS, without requiring time and advanced skills of the user.

Forecasts are used to predict the uncertain outcome of a variable. These predictions are made to get an understanding of likely future scenarios which allows planning in advance. Forecasts are commonly used in inventory control systems to estimate the future demand. This estimation along with the estimated precision of the forecast can be used to determine adequate safety stocks. In extension, forecasts of the future demand can be used to support decisions regarding the replenishment of inventories.     This thesis involves forecasting of the demand of pharmaceutical drugs. In particular, drugs that are referred to as generics. The demand of generics can fluctuate heavily due to the substitution system and can therefore be troublesome to forecast. The main objective of this thesis is to design a suitable forecast approach for the demand of generics, and to examine how these forecasts can be used to control the replenishment of inventories. The project was executed at a pharmaceutical drug distributor and hopes to enlighten some new techniques that can be used to improve the handling of generics. To achieve the objective of this thesis, the initial focus was on the current state. The currently used methods where studied and compared with theories and methods described in literature. Assumptions and theories on which the currently used methods are based on could thus be identified. These assumptions where later assessed as either reasonable or unreasonable. Finally, a new forecast approach was designed to account for the insights gained from evaluating the current methods. The result of this thesis is a forecast approach suitable to forecast the demand of generics that account for the fluctuation in demand which occurs due to the substitution system. It assumes that the demand has a constant demand model, but an alternative method suitable for the trend model is also given. It is proposed that tracking signals are used to monitor the forecast such that systematic errors are identified. Furthermore, the literature review indicates that alternatives to the current method used to determine the reorder point should be considered for occasionally demanded generics.

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The paper industry is a highly energy consuming process which also facing huge challenges as the global demand of paper products constantly decreasing. Therefore, the importance of energy optimizing the process becomes more and more crucial. The purpose of this work was to contribute to the energy optimization work at Kvarnsveden paper mill in Borlänge by mapping the energy consumption and analyzing particular areas with potential of optimization. Furthermore, analysis of the process parameters tinting colors, moisture profile and the pulp refiners in order to decrease the material losses were performed. The results from the analysis of tinting colors and moisture profiles provided the operators with reference intervals which stated how to run the parameters in order to produce paper of approved quality. The purpose of analyzing the refiners was to investigate if the quality of the mass could be predicted by specific energy instead of Freeness and average fiber length, which is the method used today. The result of this analysis shows that this is not possible today. However, specific energy is a valuable parameter in order to predict process malfunctions. The result of the energy mapping shows that the total specific energy consumption to produce one ton paper is 4,1 MWh/ton. Furthermore the energy mapping shows that every ton of paper that doesn’t clear the quality control and has to be re-produced consumes additional 1,3 MWh/ton of energy, which means that the total amount of energy for reproduced paper is 5,4 MWh. The amount of energy that is necessary to re-produce shows the importance of producing quality approved paper the first time, and since PM12 is capable of producing 1 ton/min at normal operating speed, the amount of paper that has to be re-produced can increase very fast. Hopefully, the results from the analysis of tinting colors and moisture profile will contribute to a decreased amount of papers that has to be re-produced. Furthermore the energy mapping shows some areas with energy optimization potential. Partly by maintenance and repairs of heat exchangers and steam condensers and partly by terminate the heating of buildings that has no use in the production today.

Cloud computing is a modern model for having on demand access to a pool ofconfigurable resources like CPU, storage etc. Despite its relative youth however, it has already changed the face of present-day IT. The ability to request computing power presents a whole new list of opportunities and challenges. Virtual machines, containers and bare-metal machines are the three possible computing resources which a cloud user can ask from a cloud provider. In the context of this master thesis, we will discuss and benchmark these three different deployment methods for a private OpenStack cloud. We will compare and contrast these systems in terms of CPU, networking behavior, disk I/O and RAM performance in order to determine the performance deterioration of each subsystem. We will also try to empirically determine if private clouds based on containers and physical machines are viable alternatives to the traditional VM based scenario.To achieve these goals, a number of software suites have been selected to act as benchmarks with the aim of stressing their respective subsystem. The output of these benchmarks is collected and the results are compared against each other. Finally, the different types of overhead which take place between these three types are discussed.

This final thesis is made by a student at Mälardalens högskola in Västerås from the academy of Innovation, Design and Engineering. This report examines the possibility of upgrading and modernizing current aircraft maintenance hangars by using the latest technologies.   Aircraft maintenance is essential to keep aircraft’s continuing airworthiness, and making sure it’s always declared fit for flight. But the maintenance procedures in hangars today can be seen as a bit old-fashioned. This report is therefore aiming to explore the possibilities of building the hangar of the future, where the latest technologies is used for an easier, more accurate and faster maintenance. A big problem that this project could solve in case that it could be a reality is damage assessment. In flight industry is it a bit tricky to assess a damage that had happened to an aircraft with the current methods that are used in today’s maintenance hangars. Taking measures for damages isn’t easy, and it’s even harder to look into the Structure Repair Manual (SRM) in theory and follow it in reality to assess the damage. It is something that technicians and engineers suffer from, because of the big responsibility that it withholds.   In the process of writing this thesis, and with the help of literature studies, an interview with the SAS engineer Anders Dalén, researches about the subject and the term of HOF at other companies the purpose of this thesis was reached. Which is exploring if HOF can be a reality in the near future. As for the technology of the project, it could be explained as a process or a chain that contains some steps. The idea is that an aircraft would roll into the hangar and get scanned by a stationary 3D scanner that is placed in the top of the hangar entrance. The data that the scanner later sends into a computer system gets processed by two or more programs in order to detect possible damage. If damage is found, then it would get measured with a portable 3D scanner. The analyzing programs would process its data and give an assessment on the damage, and also suggestions for reparations.   The conclusion for this thesis is that it is, in theory, possible that “Hangar of the future” can be a reality in the future. Because the technologies that is required for it do exist in our time, though they exist in other forms/ branches.

An artificial limb driven by myoelectric signals provides individuals suffering from upper limb amputation a means to perform some daily activities that would otherwise be impossible to perform. Although promising, the functionality of the limb is however still limited due to signal drift and changing requirements for different daily activities. The ability for the user to adjust control parameters on the artificial limb in real time could enhance the quality of life for these people by improving the performance of the artificial limb. During this master thesis, a mobile platform for communication and configuration of an artificial limb has been developed based on previous work by Max Ortiz C et al. The communication between the embedded system and the mobile application is based on a bluetooth standard and have been verified in conjunction with a customized communication protocol.Qualitative validation was performed by analyzing a collected questioner from one patient suffering an upper limb amputation. The results showed that functionality of the artificial limb is still one of the most important areas that needs to be improved. In addition, the most important types of feedback currently lacking were tactile feedback and elbow functionality. Quantitative experimental tests showed a statistically significant improvement in terms of both artificial limb response time and movement prediction accuracy when the threshold value, used by the control system to make a movement prediction, was adjusted in real time through the mobile application as compared to having a fixed threshold. These results shed new light on the potential benefits of using a mobile interface for real-time adjustment of limb parameters.

Managing stormwater in dense urban environments is and will in the future be a challenge for all the parts affected by it. The climate is changing and with it the extent of extreme rainfalls. This Bachelor´s thesis aims to analyze if raingardens could be of use when managing stormwater on courtyards on beam supported slabs. It is not uncommon that water drainage systems in these places are insufficient which in some cases leads to water damaged buildings. By locally treating and storing stormwater it could be possible to prevent damages on buildings and the environment even though the climate is changing.   A case in Stockholm Sweden, a privately-owned property, was investigated. In which a solution of managing storm water by using rain gardens was suggested. The study concludes that locally managing storm water could prevent flooding and water damages on those kinds of courtyards and the buildings in its vicinity. / Dagvattenhantering i täta stadsmiljöer är en framtida utmaning för både kommuner, byggsektorn och för fastighetsägare. Med hänsyn till ett framtida förändrat klimat förutses den totala nederbörden i framtiden att öka. Extrema skyfall med höga toppflöden förutses bli fler och intensivare. I detta examensarbete undersöks huruvida regnbädd kan var ett alternativ som lokal dagvattenhantering på bjälklagsgårdar. Bland äldre bebyggelse är innergårdar på bjälklag ett vanligt inslag. Dagvattenavledningen från innergårdar av den sorten är inte alltid tillräcklig och vatten riskerar då att tränga då in i byggnadsdelar. Lokal fördröjning av dagvatten kan vara ett sätt att avhjälpa och förbereda även äldre bebyggelse för ett förändrat klimat. Ett typfall i Stockholm har studerats där en dagvattenanläggning i form av regnbädd föreslås på en privat fastighet. Resultatet visar på att en lokal fördröjning där dagvatten från ovanliggande takytor leds till regnbäddar kan förebygga risken för översvämning i fastighetens byggnad