Region-based memory management offers several important advantages over garbage-collected heap, including real-time performance, better data locality and efficient use of limited memory. The concept of regions was first introduced for a call-by-value functional language by Tofte and Talpin, and has since been advocated for imperative and object-oriented languages. Scope memory, a lexical variant of regions, is now a core feature in a recent proposal on Real-Time Specification for Java (RTSJ). In this paper, we propose a region-based memory management system for a core subset of Java. Our region type analysis can completely prevent dangling references and thus is ready to cater for the no-dangling requirement in RTSJ. Our system also supports modular compilation, which is an important feature for Java, but was missing in recent related work. / Singapore-MIT Alliance (SMA)

This thesis has been carried out in cooperation with a company which develops mobile sensor platforms. The sensors measure different types of data such as temperature, pressure etc.. They will communicate through the internet with a server that stores data in a database. This system will be controlled and monitored through a web page. The project's aim has been to develop this system and to implement a server, a database, a website and a client application that simulates sensor signals. In addition, the performance of the server should be measured and a usability test should be performed. To measure the performance of the server, different variants of the client program, which continuously sent data from an increasing number of clients to the server, were developed. In the usability test the participants had to solve a number of tasks after which they answered a survey and were interviewed.The result is a communication system that works according to the requirements and a client program that is also used for testing the server. The investigation of the server performance showed a maximum bandwidth of about 370 kb/s while serving up to 70 clients. The database consumed 95% of the bandwith. However, with a rising number of clients there was a continous decline in the performance. In usability tests, there was a big difference in how people perceive computer programs depending on their experience and education. For this application, the server worked well, but if the project is to be developed into a large scale, it then becomes relevant to move onto an asynchronous working server instead of a thread-server. Queries to a database (MySQL) considerably decreases bandwidth and should be optimized where possible.

This thesis project concerns NAT traversal techniques and their application to P2P networking with regard to MediaSense platform. Since MediaSense open source platform, developed by Mid Sweden University, utilizes the benefits of P2P networking, it also suffers from the drawbacks provided by NAT. The issue of NAT traversal is not trivial due to the fact that the behavior of NAT devices is not standardized and vendors are free to provide their own implementations. The common knowledge is, that at least four main types of NATs exist, differing in the filtering and mapping algorithms employed. NAT traversal techniques vary accordingly. No single technique can handle all the cases. Most of the techniques can handle up to three main types of NAT. The last type is usually used in large corporate networks and is called the Symmetric NAT. The most viable, and basically the only available technique for its traversal, is data relaying. This thesis builds a NAT traversal module for the MediaSense platform. The main purpose of this module is to provide seamless NAT traversal capabilities to the platform. The module does this in several steps: UPnP enabled device discovery, NAT type determination and data relaying via the proxy. Firstly the module attempts to discover the presence of a UPnP enabled Internet Gateway Device on the network. If such a device is present on the network, a port mapping can be created, making the node located behind NAT accessible from the public Internet. If a UPnP enabled device was not found, the module will try to determine the type of NAT used. Based on the type of NAT used, the module can transit to either the proxy mode or request assistance of the STUN server to keep the created mapping alive. The resulting chapters provide the reader with the output produced by each step, conclusions the author has made while working on this project and some general ideas on future work within the subject.

Som underlag för den här rapporten använder vi oss av vårtspel Go Supernova. Det är skrivet i Java med hjälp avramverket LibGDX. Vi har undersökt hur man kan optimeraspelet för att kunna hantera så många objekt som möjligt menändå hålla ett bra spelflöde utan att förstöra den vision vihade när vi skapade spelet från första början. Vi har kommitfram till att ljusmotorn box2dlights använder sig av mycketprocessorkraft och användningen av den behövde justeras föratt tillfredsställa våra krav. Vi kommer även att tala omdesignval av spelets interna delar som gjorde att vi kundeundvika prestandaförluster.

Ces dernières années, des recherches ont été menées sur plusieurs techniques reliées à la collection des déchets. Plusieurs découvertes centrales pour le ramassage de miettes par copie ont été réalisées. Cependant, des améliorations sont encore possibles. Dans ce mémoire, nous introduisons des nouvelles techniques et de nouveaux algorithmes pour améliorer le ramassage de miettes. En particulier, nous introduisons une technique utilisant des cadres délimités pour marquer et retracer les pointeurs racines. Cette technique permet un calcul efficace de l'ensemble des racines. Elle réutilise des concepts de deux techniques existantes, card marking et remembered sets, et utilise une configuration bidirectionelle des objets pour améliorer ces concepts en stabilisant le surplus de mémoire utilisée et en réduisant la charge de travail lors du parcours des pointeurs. Nous présentons aussi un algorithme pour marquer récursivement les objets rejoignables sans utiliser de pile (éliminant le gaspillage de mémoire habituel). Nous adaptons cet algorithme pour implémenter un ramasse-miettes copiant en profondeur et améliorer la localité du heap. Nous améliorons l'algorithme de collection des miettes older-first et sa version générationnelle en ajoutant une phase de marquage garantissant la collection de toutes les miettes, incluant les structures cycliques réparties sur plusieurs fenêtres. Finalement, nous introduisons une technique pour gérer les gros objets. Pour tester nos idées, nous avons conçu et implémenté, dans la machine virtuelle libre Java SableVM, un cadre de développement portable et extensible pour la collection des miettes. Dans ce cadre, nous avons implémenté des algorithmes de collection semi-space, older-first et generational. Nos expérimentations montrent que la technique du cadre délimité procure des performances compétitives pour plusieurs benchmarks. Elles montrent aussi que, pour la plupart des benchmarks, notre algorithme de parcours en profondeur améliore la localité et augmente ainsi la performance. Nos mesures de la performance générale montrent que, utilisant nos techniques, un ramasse-miettes peut délivrer une performance compétitive et surpasser celle des ramasses-miettes existants pour plusieurs benchmarks. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Ramasse-Miettes, Machine Virtuelle, Java, SableVM.

Testing concurrent programs remains a difficult task due to the non-deterministic nature of concurrent execution. Many approaches have been proposed to tackle the complexity of uncovering potential concurrency bugs. Static analysis tackles the problem by analyzing a concurrent program looking for situations/patterns that might lead to possible errors during execution. In general, static analysis cannot precisely locate all possible concurrent errors. Dynamic testing examines and controls a program during its execution also looking for situations/patterns that might lead to possible errors during execution. In general, dynamic testing needs to examine all possible execution paths to detect all errors, which is intractable. Motivated by these observation, a new testing technique is developed that uses a collaboration between static analysis and dynamic testing to find the first potential error but using less time and space. In the new collaboration scheme, static analysis and dynamic testing interact iteratively throughout the testing process. Static analysis provides coarse-grained flow-information to guide the dynamic testing through the relevant search space, while dynamic testing collects concrete runtime-information during the guided exploration. The concrete runtime-information provides feedback to the static analysis to refine its analysis, which is then feed forward to provide more precise guidance of the dynamic testing. The new collaborative technique is able to uncover the first concurrency-related bug in a program faster using less storage than the state-of-the-art dynamic testing-tool Java PathFinder. The implementation of the collaborative technique consists of a static-analysis module based on Soot and a dynamic-analysis module based on Java PathFinder.

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MindMe is an aid for people with cognitive memory impairments. The aid is completely new and has been developed within this bachelor thesis, no product of this nature could be found on the market before. The idea came from Niclas Jarhäll, CEO of Mutual Benefits. Mutual Benefits were also partners in the project. The project was carried out by us in cooperation with Bachelor of Science in Innovation Engineering students Malin Albertsson and Victoria Hedman at Halmstad university. The aid consists of a mobile phone and a number of tags. The goal was for the mobile phone and tag to set of their alarms when they get a certain distance apart. It is the technical part of the project that will be discussed in this paper and it was divided in two parts, prototype development and software for the mobile phone. The project resulted in a prototype and an application for the mobile phone. The prototype and mobile phone set of their alarms when they come to far apart. The user has the option to change settings in the mobile phone application that affects both phone and tag and to add/remove tags. Both application and tag meet the requirements set in the technical specification.

A problem with the widley usedanticoagulant medicine Warfarin hasalways been that the therapeutic dosevaries from person to person and thatthere has not been any methods toestimate individually-based dosingregimens. By using a new populationmodeldescribing the relationship betweenWarfarin dose and INR(internationalnormalized ratio) response fordifferent individuals based on their age,weight and genotypes, a user friendly,dose estimating program has beendeveloped in Java. The applicationestimates the INR given the individualparameters and dosing, but it's alsopossible to estimate the predicted dosegiven the desired INR. The applicationmakes it possible for others to take partof the model, and to give a moreindividualized Warfarin treatment inclinical practice.

Using design patterns is a widely accepted method to improve software development. There are many benefits of the application of patterns claimed in the literature. The most cited claim is that design patterns can provide a common design vocabulary and therefore improve greatly communication between software designers. Most of the claims are supported by experiences reports of practitioners, but there is a lack of quantitative research concerning the actual application of design patterns and about the realization of the claimed benefits. In this paper we analyze the development process of over 1000 open source software projects using version control information. We explore this information to gain an insight into the differences of software development with and without design patters. (author's abstract) / Series: Working Papers on Information Systems, Information Business and Operations