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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Authorization for Industrial Control Systems

Niklas, Hjern, Jonas, Vistrand January 2014 (has links)
Every day more and more devices are getting connected to the Internet, a phenomenon commonly referred to as the Internet of Things. Since security and privacy are more important than ever before this presents an interesting problem. Suddenly devices with not even near as much computing power as a desktop computer are tasked with performing heavy security computations designed to be used in powerful systems with little resource and power limitations. This thesis presents a solution for performing authorization for a resource limited system using a trusted third party, thus transferring the usually quite heavy authorization computations from a resource constrained device to another device where no such restrictions exists. When a client wishes to request a resource on the constrained device it must first retrieve authorization information from the third party and include this in the request. The authorization information is then validated by confirming that it originates from the trusted third party using a shared secret. In this thesis the constrained system is represented by an ABB control system of model 800xA and by transferring the authorization cost to another system the increased amount of resource usage on this device is kept to a minimum. It is also shown that this increase is negligible compared to the increase in resource usage when authentication and message protection in the form of TLS was implemented. / <p>Thesis conduced in cooperation with ABB AB. Supervisors: Ludwig Seitz - SICS, Andreas Bäckman - ABB</p>
52

Studie av 3d-visualiserad interaktiv monteringsanvisning : För pulsgivare

Höglind, Mattias January 2007 (has links)
No description available.
53

Tempus Custode : En GPS-tidrapporteringsapplikation

Fryxelius, Peter, Oscar, Ternström January 2014 (has links)
This paper describes Tempus Custode, a smartphone application with which the user may register working hours and travel time during the work day. The application communicates with a database via a server. The data stored in the database may be manipulated using an administrator tool, mainly for the composition of time reports. In this way, the user’s task of time reporting his day is greatly simplified. The application is able to automatically discriminate between work time and travel time, as it continuously fetches positioning data from the smartphone GPS receiver. There is a personal integrity issue inherent in this operation, because an employer may supervise an employee’s position during the work day. The application may still, with some qualifications, be in accordance with the Swedish Personal Data Act. The Tempus Custode project comprises one tentatively complete application that runs on all modern smartphones. A simple server has been implemented, together with a database. The administrator tool has not been developed. Data in the database are otherwise viewed and manipulated. The results of testing the system have been satisfactory, leading the authors to claim that the project’s objective has been fulfilled: Tempus Custode can significantly simplify the work day of the user, by offering simple, semi-automatic, GPS time reporting. / Denna uppsats beskriver Tempus Custode, en smarttelefonapplikation med vilken användaren kan registrera arbetstid och restid under arbetsdagen. Applikationen kommunicerar via en server med en databas. Datan som sparas i databasen kan manipuleras med ett administratörsverktyg, främst för att skapa färdiga tidrapporter. På så sätt kan användarens arbete med att tidrapportera sin dag avsevärt förenklas. Applikationen diskriminerar själv mellan arbetstid och restid, genom att applikationen löpande hämtar GPS-data från smarttelefonens GPS-mottagare. Det finns ett integritetsproblem i och med detta förfarande, eftersom arbetsgivaren kan följa den anställdes position under arbetsdagen. Applikationen kan ändå, under vissa förutsättningar, sägas följa personuppgiftslagen. Projektet Tempus Custode består av en mer eller mindre färdigutvecklad applikation som fungerar på alla moderna smarttelefoner. En enkel server har implementerats, tillsammans med en databas. Däremot finns inget utvecklat administratörsverktyg, utan data i databasen beskådas och manipuleras på annat sätt. Resultaten från tester av systemet har varit tillfredsställande och leder författarna att hävda, att målet för projektet har uppnåtts: Tempus Custode kan väsentligt förenkla användarens arbetsdag, genom att erbjuda enkel, semiautomatisk GPS-tidrapportering.
54

Measuring and Monitoring Battery Status

Owona, Ignace Flavien January 2014 (has links)
Embedded systems are the most widespread technologies today. These technologies include hardware and software. We may meet them from simple household appliances such as the washing machine and microwave oven to more sophisticated appliances such as aircraft, medical appliances, and automobiles not to mention mobile phones, TVs and radio receivers, leisure gadgets, etc. This project thesis goal is the measurement and the monitoring of the discharge of the battery used as the energy supplier in a quadrocopter. Its particularity is that the battery monitoring is done remotely through a radio link in embedded systems. To do this, the discharge of the battery will be measured by a hardware called the charge measurer which will measure how much charge flows from the battery. The status of the battery will be transmitted to the ground by a radio transmitter device and it will be received by a radio receiver module. The monitoring of the battery status will be carried out by software implemented in IAR Embedded systems. The Monitoring of the status of the battery will happen from the ground when the quadrocopter flies. When the quadrocopter flies the user will know how fast the energy is consumed and when the flight is over, the user will know how much energy was consumed. This can help the user to monitor the energy consumption and to know when it is possible to land the appliance safely. To perform this project several important tasks will be done such as:   -Conception and the design of the current measurer circuitry -Design of the printed circuit -Laboratory testing -Simulation of the electronic circuit with the help of some tools like Orcad and PSpice -Mounting of the electronic components on the printed circuit board -Design of the software -Writing the C code in the platform IAR Embedded system
55

Online inference of topics : Implementation of the topic model Latent Dirichlet Allocation using an online variational bayes inference algorithm to sort news articles

Wedenberg, Kim, Sjöberg, Alexander January 2014 (has links)
The client of the project has problems with complex queries and noisewhen querying their stream of five million news articles per day. Thisresults in much manual work when sorting and pruning the search result of their query. Instead of using direct text matching, the approachof the project was to use a topic model to describe articles in terms oftopics covered and to use this new information to sort the articles. An online version of the topic model Latent Dirichlet Allocationwas implemented using online variational Bayes inference to handlestreamed data. Using 100 dimensions, topics such as sports and politics emerged during training on a 1.7 million articles big simulatedstream. These topics were used to sort articles based on context. Theimplementation was found accurate enough to be useful for the client aswell as fast and stable enough to be a feasible solution to the problem.
56

Scaling an Optimization Engine for a Decision Support System

Sandvik, Joel Emil January 2013 (has links)
The objective of this survey has been to determine whether an existing linearprogramming model could be used to implement a system for the optimizationwith regards to the matching of transports and requests. Realdata from Härnösands harbour was enhanced and used to simulate scenariosthat would be used and applied within the system. The LINGOsolverwas integrated within a system that was developed in .Net to addressissues around data in- and output, data persistence, and stability.Performance tests revealed that the system and model performed inadequatelyon larger datasets. A simpler model was developed that handlea subset of the types of datasets handled by the first model, a subsetwhich includes the data collected from Härnösand harbour. The simplermodel was implemented with the AMPL/CPLEX-solver software, and furthertests showed that this provided a much improved performance to thesystem. These results indicate that further investigation might be requiredregarding the differences in performance between combinations of differentsolvers and models, and that a complete and production ready systemis likely to benefit from incorporation of various models that can be appliedto various characteristics of the input data.
57

An analysis of microservice frameworks

Edling, Erik, Östergren, Emil January 2017 (has links)
Microservice architecture has entered the industry to solve some of the problems with the monolithic architecture. However, this architecture comes with its own set of problems. In order to solve the microservice architecture problems while also providing additional functionalities, microservice frameworks have been developed. In this thesis, microservice frameworks were compared and thereafter two were chosen to implement a small part of a large monolithic system as microservices. This was done in order to see how well they could implement the different functionalities that the frameworks provided in relation to the benefits and the cross-cutting concerns of the microservice architecture which are concerns that is applicable to the entire system. The results showed that the frameworks embraced the benefits of the microservice architecture in the aspects of maintainability and scalability. However, in the terms of being able to change frameworks in the pursuit of newer technologies there were problems. Some functionalities such as service discovery requires all of the new services created to use the same mechanism in order to create a unified system. There were also problems caused by the load balancing mechanism provided by the frameworks used in this thesis. The load balancing mechanism made the system unable to send large data files which was crucial for the system that was to be implemented as a microservice system.
58

Easyfleet – A Customised Fleet Management : A case study in developing a web application that supports navigation, simplicity and customer satisfaction

Axelsson, Jonathan, Cheng, Viktor, Felippe da Silva Galeano, Renata, Hermansson, Eric, Lindholm, David, Olefalk, Simon, Shadman, Cecilia January 2017 (has links)
When vehicles are an important part of companies as part of their business operations, it arises a need for obtaining an overview of their vehicle fleet. Storing this information using old-fashioned means such as spreadsheets or whiteboards is time-consuming, inefficient and not accessible at all time. In this day and age, a web application could not only fulfill existing needs but also provide new and valuable functionality. The main advantage of storing information about a vehicle fleet in a web application would be to provide easy access to information for everyone in the organisation at all time.
59

Evaluating performance of a fault-tolerant system that implements replication and load balancing / En utvärdering av prestandan hos ett feltolerant system som implementerar replikering och lastbalansering

Gustafsson, Oskar, Hellenberg, Rickard January 2017 (has links)
Companies and organizations increasingly depend on their computer systems to help them in their work. This means that the availability of these computer systems becomes even more important as organizations are increasingly dependent on it to function. Therefore, fault tolerance needs to be considered when designing a computer system. However, when implementing fault tolerance to increase the availability it may affect the performance of the system. This thesis describes an implementation of a system that provides fault tolerance against fail-stop faults and analyzes the performance. The system consist of a primary server and a backup server and each has a GO web server and a MySQL database installed. MySQL has a built-in functionality for replication that is used to replicate the data from the primary to the replica. Two different approaches for replication are used and compared in this thesis. The system also has a load balancing server with a program called HAProxy installed. The program is used to switch between servers in case of a failure and enables load balancing between the servers, although this setup only allows for read requests to be sent to the backup server. The measurements of the implemented system shows that enabling load balancing for read requests has little effect on lower the response time when the system is under low load. For 25 users the response time was just 5 ms faster when enabling load balancing. For 50 users however, the response time was 33 ms faster when enabling load balancing. The system was evaluated using measurements of the response time and the percentage of stale data under different network loads and different requests from the system. Two different methods of replication in MySQL: asynchronous and semisynchronous were tested to see how they affect the response time and the consistency of the system. The measurements show asynchronous replication has a lower response time, but semisynchronous replication has less stale data. This means that choosing between asynchronous or semisynchronous replication is a trade-off between choosing lower response time or choosing less stale data and less risk of losing data.
60

Internet of Things – Does Particle Photon rely too much on its own cloud solution?

Karlsson, Joel January 2017 (has links)
Internet of Things is rapidly growing and there are many devices and cloud solutions on the market. This thesis addresses the usage of Particle Photon alongside Microsoft Azure and intends to determine its suitability as an IoT solution. Particle Photon is bundled with Particle Cloud which is a comprehensive solution that makes IoT simple, swift and cheap – but how good is the device if the service ceases to exist? To determine this dependency and its overall IoT suitability, tests were performed to measure transmission limitations as well as reliability both with and without the included cloud service. In addition, the research method includes a Microsoft Azure implementation. The results show that Particle Photon and Microsoft Azure makes a great IoT solution, with or without its own cloud solution – even though most of the ease-of-use and benefits comes from the cloud service. Using Particle Cloud alongside Particle Photon and Microsoft Azure reduces transmission time and increases reliability compared to only using Particle Photon.

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