Syftet med denna rapport/exjobb var att utveckla ett elektroniskt matbeställningssystem (EMS) som tillåter både kunder och restauranger att hantera matbeställningar med hjälp av elektroniska apparater (smarttelefoner, surfplattor). Anledningen till varför vi utvecklade ett EMS är p.g.a att folk i allmänhet hellre väljer att äta vid snabbmatsrestauranger istället för vid traditionella restauranger under lunchtid. Väntetiden är för lång inom traditionella restauranger idag, och tiden räcker inte till för att både vänta en längre tid på sin mat samt hinna äta den under lunchtid. Detta system erbjuder ett sätt att minska väntetider när kunder besöker restauranger. Systemet skapar även ett mer effektivt och modernt arbetssätt för restaurangpersonalen vilket till stor del förenklar deras arbete. Systemet består av fyra Androidapplikationer och en databas som lagrar data för restaurangmenyer. Genom att köra simuleringar med AnyLogic och utföra en applikationstestning i en vald restaurang, har vi fått önskat resultat, vilket visar att väntetiden minskar om man börjar använda vårt system. Väntetiden minskar med i genomsnitt 3 minuter. De utvecklade applikationerna i detta arbeta är inte slutprodukter. Det finns funktionaliteter i systemet som inte än har implementerats, som t.ex. mobilbetalningssystem, bordsbokning m.fl. Alla dessa saknade funktioner tillsammans med fler produkttestning förväntas ske i framtiden.

This thesis is about the theory behind and software development of TDE View. The application produces a graphical presentation containing graphical objects, such as charts and tables, which display real time data derived from online and currently available services in Swedbank. TDE View is a long term replacement of the previous solution, TDE System Monitor, the purpose of TDE View is to provide the ability to preview the aforementioned features online instead of local deployment. Moreover, the thesis will cover aspects regarding concepts and ideas in transferring data from different hosts in a specific network. (This report is written in English.)

In video streaming it is important that the video stream reaches the users in time, and without errors. To retransmit lost packets in a large scale multimedia video transmission is often unfeasible because of the retransmission delay. Because of that errors require either costly retransmissions or causes a downgrade of performance for the receiving user, an important goal is to minimize the number of errors that occurs when transmitting data during video streaming through a wireless channel. In this paper an adaptation-algorithm is proposed, which adapts itself in such away that the receivers of e.g. the broadcast will receive enough packets in order to be able to FEC-decode the received data in low- as well as high loss-scenarios. The algorithm adapts itself by changing the rate of FEC-encoded redundant packets based on the current packet-loss-rate of the channel, with the aim of optimizing the bandwidth-usage and providing the receiver with playable data meeting deadlines. It adds an additional self-adaptive amount of FEC-encoded redundant packets for each FEC-encoded-session in order to guarantee the ability of the receiver to FEC-decode the data and play the media, even under the conditions in which the inteference-level of the channel increases during the transmission of each such session. Simulations demonstrate that in a wireless channel with a packet loss rate of 10%, using 1000 source packets per FEC-encoded unit, 12.6% redundant packets are required in order to ensure a FEC-decoding-failure probability< 11000 .

In this Masters thesis, a method for independent characterization of nonlinear electro-optic (EO) tensor components (r13, r33) of organic polymers is presented. Organic non-linear optical (NLO) polymers provide low cost and easily process able photonic devices. The characterization setup proposed in this thesis is controlled by a LabVIEW program that allows fast, accurate and automated measurement of r13 and r33. The setup measures transmission spectrum of a Fabry-Perot cavity, filled with an NLO polymer, as a function of incident angle. It uses the changes in refractive index in the polymer due to the electro-optic effect to measure the tensor components. This method is then utilized for characterization of a Polymethylmethacrylate (PMMA), Disperse Red1 (DR1) guest-host blend sample.

Data-flow visualization for source code can help software developers and software architects to understand code graphically. In this thesis, an infrastructure for dataflow visualization is created to analyze the C source code of an embedded system of a truck. Several commercial and open-source tools for data-flow analysis are investigated and a definition for data-flow is found. A data-flow analysis tool chain consisting of FLex, a lexical analyzer generator, Bison, a parser generator, and a hand-written data-flow analysis is implemented. The tool chain saves data-flow information from the source code into an intermediate representation which can be used to create visualizations. Software developers and architects are interviewed to gather information about how data-flow visualizations are used at Scania and how the tool chain can be improved.

This thesis deals with analysis and visualization of data dependencies in embedded system software. The goal was to create a comprehensive, practical analysis tool that fits the needs at Scania well, while being as general and reusable as possible. Given the complexity of problem area, the goal was to position the outcome of this project as the basis for further development, making future extensibility an important consideration. This type of analysis has previously been performed either manually, or with help of problem-specific and system-specific tools developed by specific users for their own needs. Here, a wider user spectrum was interviewed to collect and analyze their needs in order to delimit the scope of the project and provide fundamentals of a solution that would benefit most users to the largest degree.  Application developed throughout this thesis is of a strongly layered structure, to provide most opportunity for future reuse and extension. In the first layer, XML representation of abstract syntax trees is obtained through source code analysis. This part relies on the work performed as a part of the thesis by Martin Pruscha [23], modifying and extending the tools developed for C code parsing and analysis there.  Intermediate part of the toolchain transforms this into a generalized XML representation of desired data relationships, based on detection of patterns in abstract syntax tree that correspond to code structures that signify global variables and functions within C modules, as well as their mutual dependencies, such as function calls or reading or writing to variables. While actual implementation deals only with inter-functional analysis, issues pertaining to problems necessitating intra-functional analysis of data flow (deeper pointer variable analysis, function pointers, flow of data through non-global variables) are discussed. In the final stage, based on user preferences selected via a GUI, this format is converted to GraphML format which can be graphically represented in yEd application. Finally, results and performance were analyzed to provide guidelines to future work

Machine-to-machine (M2M) communications have appeared as an advanced technology for next-generation communications and are undergoing rapid development. In this project, we investigate M2M communications in a wireless cellular network. In M2M communications, clustering is a technology for more efficient data gathering and higher network energy efficiency. We will analyze existing clustering designs in literature and propose two new clustering designs for M2M communications in cellular networks. Performance of the proposed designs will be evaluated thoroughly using both analytical and simulation tools across many aspects, including energy consumption, dead device ratio, residual energy, and network life. The results show that with simple static energy-efficient clustering operations, the network life can be extended by about 50%.

Spotify is a music streaming service that offers access to a vast music catalogue; it counts more than 24 million active users in 28 different countries. Spotify's backend is made up by a constellation of independent loosely-coupled services; each service consists of a set of replicas, running on a set of servers in multiple data centers: each request to a service needs to be routed to an appropriate replica. Balancing the load across replicas is crucial to exploit available resources in the best possible way, and to provide optimal performances to clients. The main aim of this project is exploring the possibility of developing a load balancing algorithm that exploits request-reply latencies as its only load index. There are two reasons why latency is an appealing load index: in the first place it has a significant impact on the experience of Spotify users; in the second place, identifying a good load index in a distributed system presents significant challenges due to phenomena that might arise from the interaction of the different system components such as multi-bottlenecks. The use of latency as load index is even more attractive under this light, because it allows for a simple black box model where it is not necessary to model resource usage patterns and bottlenecks of every single service individually: modeling each system would be an impractical task, due both to the number of services and to the speed at which these services evolve. In this work, we justify the choice of request-reply latency as a load indicator, by presenting empirical evidence that it correlates well with known reliable load index obtained through a white box approach. In order to assess the correlation between latency and a known load index obtained through a white box approach, we present measurements from the production environment and from an ad-hoc test environment. We present the design of a novel load balancing algorithm based on a modified ' accrual failure detector that exploits request-reply latency as an indirect measure of the load on individual backends; we analyze the algorithm in detail, providing an overview of potential pitfalls and caveats; we also provide an empirical evaluation of our algorithm, compare its performances to a pure round-robin scheduling discipline and discuss which parameters can be tuned and how they affect the overall behavior of the load balancer.

With the development of Chinese economy and globalization, there is a big requirement of young Chinese having qualified international communication skills in competitive business relationships. Facing this challenge, there is little evidence of trainings or courses in China’s higher education that contribute to the students competence, compared to their western counterparts.  In most western countries, these types of trainings were well developed. Therefore, our study choose Chines students studying in Swedish higher-education as the research objects and investigated their international communication weakness as well as figured out the valuable ICT-based practices which were able to improve their weakness. In our study,  research methods were applied, including a literature review, inductive reasoning, a hypothesis approach, an iterative approach, a pilot study, qualitative  and quantitative methods. Communication skills were identified, which were considered as the weakness faced by the Chinese students. Based on this, ICT-based practice were recommended, which were able to improve their skills. Among these practices, some of them depended on the good quality of ICT facilities and instruments. It had been evaluated that how people react to our recommendations and the results indicated that they could be useful at Chinese higher-education.  We hoped that the findings of our study and recommended practices could be implemented in the Chinese higher- education in the future. We intended to carry out further tests and to justify our conclusions and in the process contributed to the development of the Chinese higher-education.

The research work presented in this document deals with the problem of implementing high capacity mobile networks that are able to accommodate the ever increasing amounts of data traffic produced by mobile broadband users, given the dramatic expansion this service has experienced in the recent past due to the popularity of smartphones and tablets. Moreover, the analysis focuses in the feasibility of considering alternative deployment strategies that may render cost-efficient solutions while overcoming the challenges posed by the low amount of spectrum allocated to operators and the limited number of fixed telephone and internet lines available, which are characteristic of developing countries. In this context, an assessment in the scenario of the Telecommunications market in Ecuador is provided, for three specific strategies: network sharing, the use of secondary spectrum in TV white spaces, and offloading of traffic to local networks. The main factors considered are the economic situation, the penetration of fixed and mobile services, the regulatory environment, and the set up of the mobile operators in the market. Descriptions and comparisons with Chile and Sweden are included, as they present scenarios with higher levels of development, giving the opportunity to look at the way they have managed to improve the conditions in their markets and provide suggestions to allow Ecuador to follow their steps. The results show that network sharing could be feasible mostly in the way of passive sharing, given regulatory restrictions. Also, the introduction of at least one new operator could provide better conditions for this strategy. On the other hand, the use of secondary spectrum would be a great solution, but it may be hard to implement it due to regulatory delays and economic issues related to the potentially high costs mobile phones supporting cognitive radio technologies may have. Finally, offloading of traffic to local networks is possible, but limited to urban areas where the density of fixed internet and telephone lines may support the deployment of femtocells or Wi-Fi networks.