Java for parallel computing and as a general language for scientific and engineering simulation and modeling

We discuss the role of Java and Web technologies for general simulation. We classify the classes of concurrency typical in problems and analyze separately the role of Java in user interfaces, coarse grain software integration, and detailed computational kernels. We conclude that Java could become a major language for computational science, as it potentially offers good performance, excellent user interfaces, and the advantages of object-oriented structure

A Web-Based Distributed Virtual Educational Laboratory

Evolution and cost of measurement equipment, continuous training, and distance learning make it difficult to provide a complete set of updated workbenches to every student. For a preliminary familiarization and experimentation with instrumentation and measurement procedures, the use of virtual equipment is often considered more than sufficient from the didactic point of view, while the hands-on approach with real instrumentation and measurement systems still remains necessary to complete and refine the student's practical expertise. Creation and distribution of workbenches in networked computer laboratories therefore becomes attractive and convenient. This paper describes specification and design of a geographically distributed system based on commercially standard components

BUILDING A DISTRIBUTED TRUST MODEL OF RESTFUL WEB SERVICES FOR MOBILE DEVICES

As of 2011, there were about 5,981 million mobile devices in the world [1] and there are 113.9 million mobile web users in 2012 [2]. With the popularity of web services for mobile devices, the concern of security for mobile devices has been brought up. Furthermore, with more and more cooperation of organizations, web services are now normally involved with more than one organization. How to trust coming requests from other organizations is an issue. This research focuses on building a trust model for the web services of mobile devices. It resolves the issues caused by mobile devices being stolen, lost, users abusing privileges, and cross-domain’s access control. The trust model is distributed in each node of the web servers. The trust value is calculated for every incoming request to decide whether the request should be served or not. The goals of the trust model are 1) flexible; 2) scalable; 3) lightweight. The implementation is designed and accomplished with the goals in mind. The experiments evaluate the overhead for the trust module and maximum capacity of the system

Deterministic Object Management in Large Distributed Systems

Caching is a widely used technique to improve the scalability of distributed systems. A central issue with caching is maintaining object replicas consistent with their master copies. Large distributed systems, such as the Web, typically deploy heuristic-based consistency mechanisms, which increase delay and place extra load on the servers, while not providing guarantees that cached copies served to clients are up-to-date. Server-driven invalidation has been proposed as an approach to strong cache consistency, but it requires servers to keep track of which objects are cached by which clients. We propose an alternative approach to strong cache consistency, called MONARCH, which does not require servers to maintain per-client state. Our approach builds on a few key observations. Large and popular sites, which attract the majority of the traffic, construct their pages from distinct components with various characteristics. Components may have different content types, change characteristics, and semantics. These components are merged together to produce a monolithic page, and the information about their uniqueness is lost. In our view, pages should serve as containers holding distinct objects with heterogeneous type and change characteristics while preserving the boundaries between these objects. Servers compile object characteristics and information about relationships between containers and embedded objects into explicit object management commands. Servers piggyback these commands onto existing request/response traffic so that client caches can use these commands to make object management decisions. The use of explicit content control commands is a deterministic, rather than heuristic, object management mechanism that gives content providers more control over their content. The deterministic object management with strong cache consistency offered by MONARCH allows content providers to make more of their content cacheable. Furthermore, MONARCH enables content providers to expose internal structure of their pages to clients. We evaluated MONARCH using simulations with content collected from real Web sites. The results show that MONARCH provides strong cache consistency for all objects, even for unpredictably changing ones, and incurs smaller byte and message overhead than heuristic policies. The results also show that as the request arrival rate or the number of clients increases, the amount of server state maintained by MONARCH remains the same while the amount of server state incurred by server invalidation mechanisms grows

A survey of techniques and technologies for web-based real-time interactive rendering

When exploring a virtual environment, realism depends mainly on two factors: realistic images and real-time feedback (motions, behaviour etc.). In this context, photo realism and physical validity of computer generated images required by emerging applications, such as advanced e-commerce, still impose major challenges in the area of rendering research whereas the complexity of lighting phenomena further requires powerful and predictable computing if time constraints must be attained. In this technical report we address the state-of-the-art on rendering, trying to put the focus on approaches, techniques and technologies that might enable real-time interactive web-based clientserver rendering systems. The focus is on the end-systems and not the networking technologies used to interconnect client(s) and server(s).Siemens; Bertelsmann mediaSystems GmbH; Eptron Multimedia; Instituto Politécnico do Porto - ISEP-IPP; Institute Laboratory for Mixed Realities at the Academy of Media Arts Cologne, LMR; Mälardalen Real-Time Research Centre (MRTC) at Mälardalen University in Västerås; Q-Systems

A User-Centric Access Control Framework for Cloud Computing

A huge amount of data is generated due to the growth of advanced information technology, online availability and easy access to cloud computing. In cloud computing, user can easily store and share their information across the cloud. With the rapid growth of cloud computing, user’s security and privacy has become a serious concern. Despite various existing security mechanisms, enterprises are still afraid of losing their outsourced data and unauthorized access. In most cases, access control mechanism and authorization rule follow a web application. This makes it limited, tightly bound to web application functionality and also doesn’t complete the security requirements for the individual user that results in poor protection against unauthorized access. To overcome the issue of privacy and protection, a suggestion is given in this study to empower the owner of any piece of data and information to protect their resource according to their own semantics. In this thesis, a new approach is presented that externalize access control policy and empower the user to control access on their data according to their semantics and wishes. The proposed framework provides PKI standard base secure access control mechanism and describes the protocol interface between the different components to enforce user-centric access control policy