Inaug.-diss.--Utrecht.

Webben är en framgångssaga. Men vilka tekniska egenskaper gör den framgångsrik?Dr. Roy Fielding identifierade dess stora fördelar och vilka arkitektoniskarestriktioner som främjar dessa. REpresentational State Transfer, ellerREST, är en arkitektonisk stil som samlar dessa restriktioner under en akronym.REST kan användas för att ge webbens positiva egenskaper till webbservicessom konsumeras av automatiserade klienter. Uppdraget har varit att implementeraett Application Programming Interface (API) på ett befintligt system föravtalshantering. API:et ska vara RESTful. Vad detta egentligen innebär verkarinte helt solklart. En stor del av arbetet har legat i att studera Fieldings avhandlingoch reda ut begreppen. Det centrala i REST är det enhetliga interfacet, sominnebär att system, oberoende av varandra ska kunna förstå de meddelandensom hanteras. Det utvecklade systemet har utvärderats mot definitionen avREST och systemet saknar den essentiella delen Hypertext As The Engine OfApplication State (HATEOAS). Denna del är också vad som verkar vara denmest missförstådda, eller till och med helt ignorerade delen av REST. HATEOASinnebär att servern genom länkar, dynamiskt serverar klienten med de vägarklienten kan navigera API:et. Detta leder till att ny funktionalitet kan läggas tillutan att skapa inkompatibilitet med klienten. Klienten kan välja att ignorera länkarmed relationer den inte känner igen. För att REST ska vara användbart såmåste klienten förstå relationerna i API:ets länkar och representationen av dessdata. / The World Wide Web is a success. But, what technical properties made it whatit is today? Dr. Roy Fielding identified the web´s great advantages and a set ofarchitectural restrictions to guard the advantages. REpresentational State Transfer,or REST, is an architectural style gathering these restrictions under oneacronym. REST can be used to give the web´s properties to web services to beconsumed by automated clients. The mission has been to implement an ApplicationProgramming Interface (API) on top of a system for contract handling.The API should be RESTful. What RESTful actually means seems unclear. Themajor part of the work has been to study Fieldings dissertation, sorting out thecharacteristics. The central part of REST, is the uniform interface. It allows intermediarynodes to understand the meaning of a message without knowinganything else about the sender. The system developed has been evaluatedagainst Fieldings definition of REST, still the system lacks Hypertext As TheEngine Of Application State (HATEOAS). This part seems to be the mostwidely misunderstood part of REST, often completely ignored. HATEOASgives the server the power of steering the client through the API, by always providinglinks to the available steps. This leads to the ability to add functionalityto the API without breaking the client. The client can just ignore the links that itdoes not know how to handle. For REST to be useful by automated clients, theclient needs to understand the link relations and the data representations of theAPI.

Concurrent programming has become ubiquitous in the arena of application development, requiring most production quality systems to deal with at least some degree of multi-threaded execution. An increasing level of maturity is developing around the impact of concurrency on the design and testing processes. Much of this knowledge focuses on the functional aspect of the design and execution with success measures typically related to the correctness of a program. However, there exists a gap in the research to date around the process for concurrent performance testing. While many companies acknowledge that performance is a major source of complaints in production environments, performance testing historically receives low priority and is often little more than an extension of the functional testing. Possibly the most widely discussed and understood implementation language today, in terms of multi-threaded programming, is Java. The report outlines a standard framework for concurrent performance testing targeted towards Java based applications. In an effort to vet the framework, we execute a series of practical concurrent testing that address some of the most common aspects of concurrent programming in Java, with a particular focus on the Java Concurrency package. As a result, this report presents a portable, extensible framework that designers can use in evaluating the range of concurrency options available in Java within their particular environment. Additionally, it provides specific insight into the performance of these options in a typical run-time environment. This includes particular attention to the comparison of traditional lock based approach to non-blocking algorithms. / text

This study proposes a new framework that can effectively apply unit testing to concurrent programs, which are difficult to develop and debug. Test-driven development, a practice enabling developers to detect bugs early by incorporating unit testing into the development process, has become wide-spread, but it has only been effective for programs with a single thread of control. The order of operations in different threads is essentially non-deterministic, making it more complicated to reason about program properties in concurrent programs than in single-threaded programs. Because hardware, operating systems, and compiler optimizations influence the order in which operations in different threads are executed, debugging is problematic since a problem often cannot be reproduced on other machines. Multicore processors, which have replaced older single-core designs, have exacerbated these problems because they demand the use of concurrency if programs are to benefit from new processors. The existing tools for unit testing programs are either flawed or too costly. JUnit, for instance, assumes that programs are single-threaded and therefore does not work for concurrent programs; ConTest and rstest predate the revised Java memory model and make incorrect assumptions about the operations that affect synchronization. Approaches such as model checking or comprehensive schedule- based execution are too costly to be used frequently. All of these problems prevent software developers from adopting the current tools on a large scale. The proposed framework (i) improves JUnit to recognize errors in all threads, a necessary development without which all other improvements are futile, (ii) places some restrictions on the programs to facilitate automatic testing, (iii) provides tools that reduce programmer mistakes, and (iv) re-runs the unit tests with randomized schedules to simulate the execution under different conditions and on different ma- chines, increasing the probability that errors are detected. The improvements and restrictions, shown not to seriously impede programmers, reliably detect problems that the original JUnit missed. The execution with randomized schedules reveals problems that rarely occur under normal conditions. With an effective testing tool for concurrent programs, developers can test pro- grams more reliably and decrease the number of errors in spite of the proliferation of concurrency demanded by modern processors.

The use of the internet has exploded with many more context aware applications for different services, simplifying the use and access for human requirements. The present situation shows an increasing number of devices from computers to sensors and actuators that are connected to the internet. MediaSense[1] is a growing framework that provides a platform for applications to connect these devices (smart-phones, sensors, actuators etc.) and provide services using the internet. Applications based on the MediaSense[1] framework access globally available sensors to provide contextual information with regards to a situation and provide better services. However, information flowing between the devices or sensors are open to the internet without any security. Thus, the focus of this thesis is on the development of a security mechanism for the MediaSense framework which is a fully distributed network. The task involves analyzing the security measures with and without centralized authority as well as the advantages and disadvantages of both scenarios regarding the MediaSense framework and proposing appropriate solutions to achieve the maximum possible security on the framework. The first challenge of this thesis is to identify different properties required for a security mechanism which is capable of secure key distribution and secure peer to peer communication among MediaSense instances without having any centralized authority. Therefore, this thesis proposes a resilient solution, namely, a security architecture for MediaSense which is capable of performing in a distributed environment with the ability of key distribution and management and thus securing the communication using different encryption techniques. The next challenge to the security architecture is to store the keys securely and prevent any unauthorized access from a third party. The thesis proposes the use of built in Java Application Programming Interface(API), “KeyStore” to store valuable keys locally. Thus, by addressing these challenges and other related issues, this thesis forms a security architecture or mechanism that is adaptive to a distributed system and utilizes encryption algorithms, key distribution and secure storage of the keys. To support these proposals, this thesis has developed a proof of concept application and prototypes to verify the approach. In addition, the thesis has implemented security features from the security architecture as an extension to the MediaSense framework. Hence, in conclusion, this thesis proposal regarding a security architecture for MediaSense has the ability to provide the necessary security together with the required key distribution mechanism to the framework without any centralized authority.

Populiarėjant AJAX technologiją naudojančioms sistemoms vis labiau aktualios darosi šios technologijos įtakojamos problemos. Verta paminėti, kad kai kurie tradicinių internetinių sistemų trūkumai dar labiau paaštrėja ir yra sunkiau aptinkami naujos kartos internetinėse sistemose. Dėl šios priežasties dauguma programuotojų anksčiau ar vėliau susiduria su įprastomis AJAX aplinkos problemomis: naršyklės navigacijos mygtukų panaudojimu, adresų išsaugojimu, paieškos varikliukų problema ir pan. Magistriniame darbe „Asinchroninių metodų interneto technologijose tyrimas“ pateikiamas AJAX pagrindu veikiančio karkaso projektas apima dažniausiai pasikartojančių problemų, kylančių kuriant šią technologiją naudojančias sistemas, sprendimus. Pateikiami sprendimai apima patį duomenų mainų mechanizmą, įskaitant patogesnio jo taikymo galimybes, navigacijos mygtukų panaudojimo problemas, suderinamumą su paieškos sistemų varikliukais, taip pat būdus kaip galima padidinti sistemos saugumą. / While internet applications based on AJAX technology becomes more and more popular, respectively problems rising from this technology becomes more and more serious. It is worth to mention, that some sorts of problems which comes from internet applications working in an old way, becomes more actual and harder to catch in systems of new generation. Due to this reason, lots of software developers sooner or later faces common AJAX problems: using of browser’s buttons, bookmarking pages, search engines (like Google) problems, etc. This work describes project of AJAX framework. Framework includes solutions for most common problems that faces programmers while developing AJAX based internet applications. Solutions covers the way of data exchange, including possibilities of using it more handy, browser’s navigation button problems, compatibility with search engines. It also covers ways in which could be increased application’s security.

In the field of education, the Islamic educational institutions, both formal and non-formal, have played a major role in educating Indonesians from the colonial era 1600-1945, to the present day. / One of the Islamic educational institutions famous for its Islamic approach is the pesantren. This institution, however, is facing major challenges at present and is being asked to update, develop and change many of its programs in order to enable its graduates to participate more fully in Indonesian national life, particularly in the field of national development. As a result, some pesantrens began modernizing their educational systems. The modernization process is accomplished through the adoption of the national education system alongside the classical system, thus providing students with secular subjects and skills training together with religious education. As is to be expected, this modernization effort has created a number of problems for pesantrens such as lack of funds, finding skilled teachers for the secular and skill subjects, building the necessary facilities and creating the needed administrative apparatus. (Abstract shortened by UMI.)

Programación orientada a objetos. 1. Lenguaje de programación java

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Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1977. / Bibliography: leaves [217]-251. / Microfiche. / xiv, 251 leaves ill., maps