Spout: a transparent proxy for safe execution of Java applets

This paper presents a distributed, multi-user virtual reality testbed for a mobile robot. The main components of the testbed include user interface, networking, simulation and robot control. The user interface is implemented as a combination of a virtual environment and a standard graphical user interface (GUI). The virtual environment is developed using the Virtual Reality Modeling Language (VRML) and it corresponds to the laboratory environment where the robot is placed and tested. The standard GUI is implemented using Java Programming language. The World Wide Web (WWW) browser is used to integrate the virtual environment (embedded VRML) and the standard GUI (Java applet) in a single user interface. Users can access a dedicated WWW server and download the user interface. Networking component (communication among users and robots) is implemented using the Distributed Interactive Simulation (DIS) protocol. The existing robot development system has been utilized to provide simulation capabilities. A separate stand-alone Java application has been developed to communicate and control the robot using a wireless Ethernet link. In addition to user's direct control, control algorithms (e.g. fuzzy logic based) can be used to replace the user. A Nomad200 mobile robot has been used for initial measurements and evaluations of the testbed.

Recently Java applets exploiting Java Security Manager's vulnerability have become serious threats to Java system security. In this paper, we analyze various kinds of malicious Java applet code and classify them according to the path they take to avoid the blockage by Java Security Manager. The result of this classification is JAPCT (Java Access Permission Checking Tree). We believe JAPCT will greatly enhance our ability to understand Java security vulnerabilities in the past and to predict possible security problems in the future Java Virtual Machine.

This paper examines how World Wide Web (WWW) usage for procurement purposes affects corporate buyers' search costs and buying organizations' coordination costs and how it ultimately affects the efficient boundaries of buying organizations. The analysis is based on a model that integrates Transaction Costs Economics (TCE) (Williamson 1975, 1985) and forces of electronic interconnections (Malone et al. 1987). Data collected from 110 corporate buyers from over 100 organizations doing business in a wide range of industries were used to test the validity of the proposed model. Findings show that WWW usage is associated with a reduction of buyers' search costs, which can give buying organizations the flexibility to increase their base of suppliers when such an increase fits their interest. No clear relationship was found between WWW usage and the reduction of coordination costs buying organizations face to integrate their value chain activities with those of their suppliers. Findings show however that a WWW‐bas...

Relationship of WWW usage and employee learning in the casino industry

DJ (Declarative Java) is an extension of Java that supports constraint programming. On the one hand, DJ can serve as a high-level specification language for Java applets. To construct a graphic user interface (GUI) with DJ, the users only need to specify the components that compose the GUI and the relationships among the components by using constraints. On the other hand, DJ, as a constraint language, improves the current constraint languages in that problems and solutions can be described in the same language. In addition, since DJ is a compiling language that uses Java as the object language for compilation, solutions can be distributed on the WWW as Java applets. We present DJ by examples, aiming at illustrating the power and programming methodology of DJ.

In the situation of monitoring an experiment, it is often necessary to control several independently running tasks from one graphical user interface (GUI). Such a GUI must be able to execute commands in the tasks even if they are busy, i.e., getting data, analyzing data, or waiting for data. Moreover, the tasks, being controlled by data streams (i.e., event data samples or slow control data), must be able to send data asynchronously to the GUI for visualization. A multitasking package (C++ class library) that meets these demands has been developed at the Gesellschaft fur Schwerionenforschung (GSI), Darmstadt, Germany, in the framework of a new analysis system, Go4, which is based on the ROOT system [CERN, R. Brun et al]. The package provides a thread manager, a task handler, and asynchronous intertask communication between threads through sockets. Hence, objects can be sent at any time from a task to the GUI or vice versa. At the GUI side, an incoming object is accepted by a thread and processed. In a task, an incoming command is queued by the accepting thread and executed in the execution thread. Utilizing the package one can implement nonblocking GUIs to control one or several tasks processing data in parallel and updating graphical elements in the GUI. The package could also be useful in building data dispatchers or in slow control applications. All components have been tested with Go4 analysis tasks and a very preliminary GUI.

The World Wide Web (WWW) on the Internet has been recognized as an effective environment to create new distributed applications that have the potential to bring instruction beyond the bounds of the classroom. The availability of browsers (e.g. Mosaic, Netscape, Hot Java) has enormously simplified the access to the WWW, and there have been numerous initiatives to take advantage of this new technology for teaching. This work will illustrate recent developments of tools for engineering education and technology transfer which take advantage of WWW browsers, Java applets, and virtual reality. We have developed modules based on WWW browsers incorporating educational and research software, including advanced visualization, which find use for multimedia classroom presentations accessible by Internet users, and which can also improve interaction among academic groups and industry. Therefore, the material is suitable for asynchronous distance learning and technology transfer. Examples of interactive WWW applications include device simulation, semiconductor band structure calculation, numerical techniques, and electromagnetics.

The practitioner interested in reducing software verification effort may found herself lost in the many alternative definitions of Graphical User Interface (GUI) testing that exist and their relation to the notion of system testing. One result of these many definitions is that one may end up testing the same parts of the Software Under Test (SUT), specifically the application logic, twice. To clarify two important testing activities and avoid duplicate testing effort, this paper empirically evaluates to what extent GUI tests exercise the application logic of the software under test (and not only the GUI code). Experimental results show that GUI tests do not necessarily entirely exercise application logic functionality, at least not as much as system tests directly interacting with application logic code.

Este artigo apresenta programas na forma de Java applets para um sistema de auxílio ao ensino multimídia de um curso em Eletrônica de Potência baseado na WWW (world wide web). Os programas foram desenvolvidos com o propósito de analisar os circuitos retificadores não-controlados (a diodos) e controlados (a tiristores), monofásicos e trifásicos, idealizados e em regime permanente, permitindo a simulação visual e interativa dos mesmos. Além disso, este artigo aborda o desenvolvimento e a utilização de Java applets para resolução de algumas equações de projetos orientados para aplicações destes retificadores. O principal objetivo destas Java applets propostas foi o de proporcionar maiores facilidades para os estudantes aumentarem e melhorarem o ritmo de aprendizado no curso de Eletrônica de Potência, enfatizando-se as análises das formas de onda e proporcionando condições para uma efetiva análise comparativa imediata (on-line) entre diferentes experiências desenvolvidas em laboratório, através da conexão TCP/IP padrão da Internet. Portanto, à partir da utilização das Java applets propostas, que estão inseridas em um sistema de auxílio ao ensino do curso de Eletrônica de Potência baseado na WWW, foi observado uma importante melhoria no aprendizado do conteúdo do curso. Conseqüentemente, a estrutura do curso tornou-se mais fluída, permitindo efetivamente um curso on-line através da WWW, motivando os alunos a aprender o conteúdo teórico, aplicando-o em projetos de estruturas retificadoras e nos seus deveres escolares.

The Java language environment, World Wide Web, and Common Object Request Broker Architecture are complementary software technologies, which when used together provide a powerful set of tools for developing and deploying multi-user distributed applications. We describe an approach to building reasonably sophisticated and easy-to-use client software as WWW-downloadable Java applets, which use CORBA to interact effectively with remote server software and thus coordinate and control access to a set of shared resources. We used this approach to reimplement a portion of an existing multi-user distributed application that had been built using the WWW Common Gateway Interface (CGI), then evaluated the differences between the two approaches. We found our method of combining Java applets and CORBA not only practical but in many ways superior to the widely used CGI approach, as well as to a conventional CORBA approach that does not exploit the WWW.

Tele-operated laboratory experiments are monitored or operated by visualization systems. In case of using a web browser the rapidly evolving web technology generates an increasing variety of client platform applications. Therefore, solutions are often obsolete after a short life time. New browser versions do not support earlier versions of web technology or browsers of different developers differ in the completeness of implemented web technology. The close coupling of the visualization system's functionality and implementation technology caused by Java Applets or Java Beans requires a completely new implementation of the whole solution although its functionality does not change. An interesting method for improving this approach is the Model Driven Software Development (MDSD). This paper presents an XML-based Graphical User Interface Language, which follows this idea and shows the currently available models. The paper presents first experiences in the design of user interfaces for laboratory experiments.

The sections in this article are World Wide Web—The Java Environment Java and Java Applets Java Programming and Development Environments Hot Java and Java‐Enabled Browsers Javascript Combining Java with Distributed Objects—Java and Corba Summary and Trends

La búsqueda de información a través de la World Wide Web es una tarea común hoy en día. Sin embargo, es sobre todo una experiencia textual. Este trabajo propone e implementa un entorno 3D para la representación de los resultados de búsqueda Web en un entorno en tres dimensiones (3D) que es controlada por gestos y reconocimiento de voz. Con el fin de hacer eso, se requieren dos escenarios: una solución de servidor basado en Servicios Web XML que permite ser consumidos por los clientes que están buscando información en la Web; y una aplicación en cliente que permite ser ejecutado como una interfaz gráfica de usuario en el escritorio mediante el uso de comandos de voz y gestos. Esta última aplicación se encarga de modelar gráficamente el entorno 3D de acuerdo con los resultados de búsqueda Web. Un prototipo del sistema propuesto fue implementado, lo que representa un conjunto de resultados de búsqueda Web en un entorno 3D. El escenario 3D es manejada por gestos y comandos de voz; el entorno 3D se basa en la administración de algunas transformaciones 3D tales como la rotación y el escalado de las caras interiores de un toroide. Una evaluación del prototipo en contextos de búsqueda sugiere que hay un alto nivel de aceptación del usuario del modelo multimedia propuesto. Las personas que probaron el prototipo han dicho que tiene una interfaz gráfica de usuario intuitiva, y que tanto el habla como el reconocimiento de gestos han sido una alternativa altamente funcional para las tareas relacionadas con la búsqueda Web. Sin embargo, hay algunos aspectos a mejorar, sobre todo en el apoyo de reconocimiento de voz de diferentes acentos. En general, el prototipo multimedia cumplió con las expectativas de una muestra de los usuarios finales, lo que demuestra que este tipo de interfaces tienen un gran potencial.

Software Development for Programmable Logic Controllers - A Methodology and a System

Chapter 4.2 - Perspective: Geographical Information Systems