A software toolkit for web-based virtual environments based on a shared database

We propose a software toolkit for developing complex web-based user interfaces, incorporating such things as multi-user facilities, virtual environments (VEs), and interface agents. The toolkit is based on a novel software architecture that combines ideas from multi-agent platforms and user interface (UI) architectures. It provides a distributed shared database with publish-subscribe facilities. This enables UI components to observe the state and activities of any other components in the system easily. The system runs in a web-based environment. The toolkit is comprised of several programming and other specification languages, providing a complete suite of systems design languages. We illustrate the toolkit by means of a couple of examples

OpenAlea 2.0: Architecture of an integrated modeling environment on the web

International audiencePlant modeling is based on the use of a diverse set of design paradigms (L-systems, visual programming, imperative languages or sketch-based interfaces). In this poster, the architecture of a new multi-paradigm and integrated modeling environment is presented. This desktop application will become a distributed web application, allowing to run simulations on a cloud computing system and share virtual experiments on the web. The modeling environment will run on a web browser using HTML5 and WebGL technologies

WebFlow - A Visual Programming Paradigm for Web/Java Based Coarse Grain Distributed Computing

We present here the recent work at NPAC aimed at developing WebFlow---a general purpose Web based visual interactive programming environment for coarse grain distributed computing. We follow the 3-tier architecture with the central control and integration WebVM layer in tier-2, interacting with the visual graph editor applets in tier-1 (front-end) and the legacy systems in tier-3. WebVM is given by a mesh of Java Web servers such as Jeeves from JavaSoft or Jigsaw from MIT/W3C. All system control structures are implemented as URL-addressable servlets which enable Web browser-based authoring, monitoring, publication, documentation and software distribution tools for distributed computing. We view WebFlow/WEbVM as a promising programming paradigm and coordination model for the exploding volume of Web/Java software, and we illustrate it in a set of ongoing application development activities

Distributed, parallel web service orchestration using XSLT

©2005 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.GridXSLT is an implementation of the XSLT programming language designed for distributed web service orchestration. Based on the functional semantics of the language, it compiles programs into dataflow graphs which can be efficiently executed across a collection of machines in a cluster or grid environment. Calls to web services can be made using the standard function call semantics provided by the language, and occur in parallel using the dataflow model of computation. The programmer is not required to explicitly specify the parallelism, as the details of how programs are scheduled and executed in a distributed environment are abstracted away by the run-time engine. XSLT provides a higher level programming model than many other approaches to web services composition; we explore its use here as a means of easing the task of orchestrating the interactions between services. In addition to the normal XSLT syntax, our system also supports programs written in XSLiTe, an alternative syntax we have developed which uses more concise representations of language constructs, increasing the ease of development, and bringing code readability closer to that of traditional programming languages. Our goal is to ease the construction of applications based on web services composition, such as those used in eScience and other fields in which service oriented architectures are prominent.Peter M. Kelly, Paul D. Coddington, Andrew L. Wendelbor

Enhancing distributed systems through web services

The concept of Web Services has, throughout the last few years, become one of the most discussed in the academic, as well as the business world. Many hail it as a revolutionary concept, while others look at it in a sceptic manner. The fact remains that the developers of the most diffused programming languages are giving great importance to integrating and supporting the creation and utilisation of Web Services. The main advantage of Web Services is that they are based completely on XML, which gives them a very high degree of flexibility and, above all, platform independence. Systems written using one particular language, can transparently access exposed services on other systems written using different languages. This particular feature of Web Services puts them in an ideal position to be utilised as the driving force behind distributed systems. The Internet is a jungle of computers, each with their particular features, operating system and hardware platform. Such a scenario makes it very difficult to create a system, distributed over various machines, which easily adapts to such an environment and communicates with other machines in this environment. Using Web Services, this problem is naturally solved. This project aims at analysing the ways in which Web Services may be used to enhance distributed systems over the Internet framework. There are various issues which should be considered, including the software required and the security of data being transmitted.peer-reviewe

Model-based, event-driven programming paradigm for interactive web applications

Applications are increasingly distributed and event-driven. Advances in web frameworks have made it easier to program standalone servers and their clients, but these applications remain hard to write. A model-based programming paradigm is proposed that allows a programmer to represent a distributed application as if it were a simple sequential program, with atomic actions updating a single, shared global state. A runtime environment executes the program on a collection of clients and servers, automatically handling (and hiding from the programmer) complications such as network communication (including server push), serialization, concurrency and races, persistent storage of data, and queuing and coordination of events.National Science Foundation (U.S.) (Grant CCF-1138967)National Science Foundation (U.S.) (Grant CCF-1012759)National Science Foundation (U.S.) (Grant CCF-0746856

D 3 -MapReduce: Towards MapReduce for Distributed and Dynamic Data Sets

International audienceSince its introduction in 2004 by Google, MapRe-duce has become the programming model of choice for processing large data sets. Although MapReduce was originally developed for use by web enterprises in large data-centers, this technique has gained a lot of attention from the scientific community for its applicability in large parallel data analysis (including geographic, high energy physics, genomics, etc.). So far MapReduce has been mostly designed for batch processing of bulk data. The ambition of D 3-MapReduce is to extend the MapReduce programming model and propose efficient implementation of this model to: i) cope with distributed data sets, i.e. that span over multiple distributed infrastructures or stored on network of loosely connected devices; ii) cope with dynamic data sets, i.e. which dynamically change over time or can be either incomplete or partially available. In this paper, we draw the path towards this ambitious goal. Our approach leverages Data Life Cycle as a key concept to provide MapReduce for distributed and dynamic data sets on heterogeneous and distributed infrastructures. We first report on our attempts at implementing the MapReduce programming model for Hybrid Distributed Computing Infrastructures (Hybrid DCIs). We present the architecture of the prototype based on BitDew, a middleware for large scale data management, and Active Data, a programming model for data life cycle management. Second, we outline the challenges in term of methodology and present our approaches based on simulation and emulation on the Grid'5000 experimental testbed. We conduct performance evaluations and compare our prototype with Hadoop, the industry reference MapReduce implementation. We present our work in progress on dynamic data sets that has lead us to implement an incremental MapReduce framework. Finally, we discuss our achievements and outline the challenges that remain to be addressed before obtaining a complete D 3-MapReduce environment

Empirical Evidence Justifying the Adoption of a Model-Based Approach in the Course Web Applications Development

With the ever-increasing role of business people in software development there is a growing need for business schools to offer courses in e-business and e-commerce applications development. This paper presents the results of a student survey evaluating the applications development skills acquired by business students exposed to two different approaches to teaching the course E-business applications development. The first group was taught using a model-based approach, while the second one was taught using a traditional code-based approach. In the model-based approach the environment model of evaluation was used to introduce the basic programming constructs. The UML Web Modeler profile and statecharts were employed to abstract from the intricacies and the distributed nature of Webbased information systems. A major constituent of this approach was the development of a system model. The underlying assumption was that adopting a model-based approach would enhance students' ability to think and reason formally about, develop rigorously, and program better E-business applications. The contention was that learners would perceive coding as yet another view in the system model. It was believed that having defined the components ' interfaces, students would be bound to experience fewer difficulties when writing the code. In the code-based approach students are exposed to Web programming without being required to develop a system model