XML and Web Services for Astronomers

This tutorial will be a conceptual introduction to XML technologies and their use in Web services, with examples and applications taken from astronomy. It will be assumed that the audience is familiar with HTML as well as concepts of object-oriented programming. The programming examples will use Java, although this will be a small part of the total material. Upon completing this tutorial, the student should be able to read and write XML documents, create XML Schemas and XSL Transformations, programmatically consume and create XML documents, and build a simple Web service

Application of Web Services to a Simulation Framework

The Joint Semi-Automated Forces (JSAF) simulator is an excellent tool for military training and a great testbed for new SAF behaviors. However, it has the drawback that behaviors must be ported into its own Finite State Machine (FSM) language. Web Services is a growing technology that seamlessly connects service providers to service consumers. This work attempts to merge these two technologies by modeling SAF behaviors as web services. The JSAF simulator is then modeled as a web service consumer. This approach allows new Semi-Automated Forces (SAF) behaviors to be developed independently of the simulator, which provides the developer with greater flexibility when choosing a programming language, development environment, and development platform. In addition to new SAF behaviors, this approach also supports any external component that can be modeled as a web service. Furthermore, these services are often run over a network, which distributes the computational load across several computers. Finally, hosting copies of a single service on several machines, a concept similar to file-sharing mirrors, offers an environment for load-balancing. This means if several entities are running the same behavior, a single server does not perform the computation for every entity. Instead, each entity is assigned to a specific server, increasing the quality of service seen by the system. A Web Services framework linking JSAF with several services is designed and implemented. Suppression of Enemy Air Defense (SEAD) behaviors written in MATLAB and a behavior recognition system are integrated with JSAF. These behaviors and the recognition tool were developed by other researchers, independent of this work. Results show that offloading computation to other machines is beneficial, especially when the simulation system is under heavy load. Preliminary results also indicate that load-balancing performs much better than using a single server

An evaluation of compression and streaming techniques for efficient transfer of XML documents with Simple Object Access Protocol (SOAP)

Masteroppgave i informasjons- og kommunikasjonsteknologi 2003 - Høgskolen i Agder, GrimstadIn SOAP, the entire XML object is generated on the server before it is returned to the client. This puts unnecessary strain on server systems in terms of both memory and CPU. The objectives are to find why SOAP does not allow streaming of responses, possible solutions to the problem and outline alternative transfer methods. Furthermore, compression techniques for a streaming SOAP environment are evaluated, as well as performance of streaming versus an alternative method of data retrieval. The feasibility study concluded that SOAP itself allows streaming of responses, but the HTTP binding does not. This binding specifies the issue of a HTTP fault code in case of a SOAP processing error, meaning the processing must be completed before a HTTP code can legally be issued. One alternative to streaming is using a Request/N-Response message pattern, and dividing the data over several responses. As HTTP only supports a Request/Response message pattern, implementing this is not possible. Either the HTTP binding must be rewritten to allow streaming of responses while processing a request or HTTP must be replaced with for example DIME as the transfer protocol for SOAP to overcome these problems. Tests are set up to find the most suitable compressor technique and to verify that streaming SOAP responses utilize server resources better then alternative transfer methods. Results show that bzip2 is the most suitable compressor technique. And that streaming utilizes memory considerably more efficient, especially with multiple clients connecting

Microsoft .NET and Security Provided by High -Level Internet Protocols

This paper describes a class of insecure .NET client applications, which avoid higher layer protocol protection through using a “raw” send and receive API. The .NET Framework rests on many other Microsoft components, including the Windows Driver Model (WDM). This model supports four driver types, two of which were considered in this paper: protocol and miniport drivers. By compiling and executing client applications using the “raw” sockets interface, we demonstrate that insecure clients can be written with minimal programming effort (lines of code)

Towards Grid-Wide Modeling and Simulation

Modeling and simulation permeate all areas of business, science and engineering. With the increase in the scale and complexity of simulations, large amounts of computational resources are required, and collaborative model development is needed, as multiple parties could be involved in the development process. The Grid provides a platform for coordinated resource sharing and application development and execution. In this paper, we survey existing technologies in modeling and simulation, and we focus on interoperability and composability of simulation components for both simulation development and execution. We also present our recent work on an HLA-based simulation framework on the Grid, and discuss the issues to achieve composability.Singapore-MIT Alliance (SMA

Task 20 : The SOA approach

Within this document the SOA will be examined and explained in the context of the WebPA project. The first definition will be what SOA represents. From this discussion of the basic principles will be covered with regard to the guiding principles surrounding SOA to the specific architecture principles. From this point the available SOA technologies are identified and examined. The overall advantages and disadvantages of the system can be found in Appendix 2 – A Comparison of Web Service Technologies. One of the most important aspect of SOA to the WebPA project are the existing frameworks and specifications that can be utilised. This encompasses the relevancy of some of the ELF projects to WebPA. This document also covers the other considerations that must be taken into account with regard to SOA. Finally the document is concluded and the recommendations for the project are made. Through out the document a high number of acronyms and abbreviations are used. In most instances within the body of the document where an acronym is used it is explained at that point. However, to ensure that the reader can understand all acronyms a glossary is included in Appendix 1 – Glossary

An IDE for NETCONF management applications

The development of network and system management software typically requires data models definition, the creation of specific applications respecting the data model, and yet the implementation of communication interfaces. Skilled professionals usually perform such tasks in a predefined sequence and using different development solutions, but any error or lacks in the data model frequently force to repeat several time-consuming tasks. In this paper we present an integrated development framework that simplifies the construction of NETCONF management applications, from data model specification to deployment and evaluation. The framework is available at http://atnog.av.it.pt/∼ptavares/ yangplugin

An ICT-oriented Management Solution for NGNs

NGN architecture reused several standards from the IP world, as exemplified by the Session Initiation Protocol SIP, which is ubiquitous in the majority of these network components. However, the NGN management architecture simply presented a very generic management model that follows TMN. Several management technologies are proposed, such as Web services, CORBA and SNMP, to implement management solutions. Network and systems management standardizing bodies currently promote newer technologies that aim to solve known shortcomings to these. This paper proposes a management solution for NGNs based on recent IP world technologies. The presented solution was implemented in the form of a middleware to manage NGN elements. This middleware was used in the management of an element belonging to the IP Multimedia Subsystem platform, namely the Policy and Charging Rules Function