Web Agents

Despite emerging of Web 2.0 applications and increasing requirements to well-behaved Web robots, malicious ones can reveal irreparable risks for Web sites. Regardless of behavior of Web robots, they may occupy bandwidth and reduce performance of Web servers. In spite of many prestigious researches trying to characterize Web visitors and classify them, there is a lack of concentration on feature selection to dynamically choose attributes used to describe Web sessions. On the other hand, depending on an accurate clustering technique, which can deal with huge number of samples in a reasonable amount of time, is practically important. Therefore, in this paper, a new algorithm, fuzzy rough set-Web robot detection (FRS-WRD), is proposed based on fuzzy rough set theory to better characterize and cluster Web visitors of three real Web sites. External evaluations show that in contrast to state-of-the-art algorithms, FRS-WRD achieves better results in terms of G-mean 95%, Jaccard 88%, entropy 0.36, and finally, purity 96%. Moreover, according to confusion matrixes, it can better detect malicious Web visitors.

Software testing relates to the process of executing a program or system with the intent of finding errors. Covering as much as 40 to 50 percent of the development costs and resources, software testing is an integral part of the software development lifecycle. Despite its importance, current software testing practice lacks automation and is still primarily based on highly manual processes from the generation of test cases (ie from the specifications documents) up to the actual execution of the test. Although the emergence of helpful ...

Abstract. The development of multi-agent systems on the Web requires powerful and effective coordination models, languages and patterns. Even more, it calls for an effective coordination technology, not only implementing a coordination model, but also supporting ...

Incentive mechanisms for crowdsourcing have been extensively studied under the framework of all-pay auctions. Along a distinct line, this paper proposes to use Tullock contests as an alternative tool to design incentive mechanisms for crowdsourcing. We are inspired by the conduciveness of Tullock contests to attracting user entry (yet not necessarily a higher revenue) in other domains. In this paper, we explore a new dimension in optimal Tullock contest design, by superseding the contest prize-which is fixed in conventional Tullock contests-with a prize function that is dependent on the (unknown) winner's contribution, in order to maximize the crowdsourcer's utility. We show that this approach leads to attractive practical advantages: (a) it is well-suited for rapid prototyping in fully distributed web agents and smartphone apps; (b) it overcomes the disincentive to participate caused by players' antagonism to an increasing number of rivals. Furthermore, we optimize conventional, fixed-prize Tullock contests to construct the most superior benchmark to compare against our mechanism. Through extensive evaluations, we show that our mechanism significantly outperforms the optimal benchmark, by over three folds on the crowdsourcer's utility cum profit and up to nine folds on the players' social welfare.

There are many potential users and uses for grid computing. However, the concept of sharing computing resources excites security concerns and, whilst being powerful and flexible, at least for novices, existing systems are complex to install and use. Together these represent a significant barrier to potential users who are interested to see what grid computing can do. This paper describes m-grid, a system for building a computational grid which can accept tasks from any user with access to a web browser and distribute them to almost any machine with access to the internet and manages to do this without the installation of additional software or interfering with existing security arrangements.

Abstract: The main objective of this paper is to survey, in a schematic and generic way, the major models and approaches concerning the design, construction and execution of Web information systems. We identify three different approaches--server-centric, client-centric and distributed applications--and discuss the major strengths and weaknesses of each approach in a Web context. Finally, we present our view of those models and technologies that are needed for building the kind of distributed, dynamic information systems that will ...

Incentive mechanisms for crowdsourcing have been extensively studied under the framework of all-pay auctions. Along a distinct line, this paper proposes to use Tullock contests as an alternative tool to design incentive mechanisms for crowdsourcing. We are inspired by the conduciveness of Tullock contests to attracting user entry (yet not necessarily a higher revenue) in other domains. In this paper, we explore a new dimension in optimal Tullock contest design, by superseding the contest prize-which is fixed in conventional Tullock contests-with a prize function that is dependent on the (unknown) winner's contribution, in order to maximize the crowdsourcer's utility. We show that this approach leads to attractive practical advantages: (a) it is well-suited for rapid prototyping in fully distributed web agents and smartphone apps; (b) it overcomes the disincentive to participate caused by players' antagonism to an increasing number of rivals. Furthermore, we optimize conventional, fixed-prize Tullock contests to construct the most superior benchmark to compare against our mechanism. Through extensive evaluations, we show that our mechanism significantly outperforms the optimal benchmark, by over three folds on the crowdsourcer's utility cum profit and up to nine folds on the players' social welfare.

Mobile agents provide a new abstraction for deploying functionality over the existing internet infrastructure. During the last two years, we have been working on a project that tries to overcome some of the limitations found in terms of programmability and usability of the mobile agent paradigm in real applications. In the M&M framework there are no agent platforms. Instead applications become agent-enabled by using simple JavaBeans components. In this paper we present an architecture that allows currently available web servers to become capable of sending and receiving agents in an easy way. By using this approach, existing web infrastructure can be maintained, while gaining a whole new potential by being able to make use of agent technology. Our approach involves wrapping the components inside a Java servlet that can be included in any web server supporting the Servlet Specification. This servlet enables the servers to receive and send agents that can query local information, and also enables the agents to behave as servlets themselves. We currently have used the framework with several existing commercial web servers, inclusively having the security mechanisms of the framework correctly running and integrated with the security architecture of the server.

Mobile agents provide a new abstraction for deploying functionality over the existing internet infrastructure. During the last two years, we have been working on a project that tries to overcome some of the limitations found in terms of programmability and usability of the mobile agent paradigm in real applications. In the M&M framework there are no agent platforms. Instead applications become agent-enabled by using simple JavaBeans components. In this paper we present an architecture that allows currently available web servers to become capable of sending and receiving agents in an easy way. By using this approach, existing web infrastructure can be maintained, while gaining a whole new potential by being able to make use of agent technology. Our approach involves wrapping the components inside a Java servlet that can be included in any web server supporting the Servlet Specification. This servlet enables the servers to receive and send agents that can query local information, and also enables the agents to behave as servlets themselves. We currently have used the framework with several existing commercial web servers, inclusively having the security mechanisms of the framework correctly running and integrated with the security architecture of the server.

This paper describes a portable message passing and process management platform for multithreaded applications. PT-PVM© is based on the PVM system and provides message passing and process management facilities at the thread level for a cluster of workstations running the UNIX operating system without changing the PVM system. Moreover PT-PVM© introduces advanced programming abstractions like generative communication and client/server programming at the thread level. In the first place the platform is suitable for the implementation of coordination languages, like Linda or COLA.

The World Wide Web (W3) is increasingly been seen as a platform for enabling remote access to new and existing applications from different client machines. While some applications have been deployed through specialised, proprietary W3 servers, the majority utilise the CGI interface provided by standard servers to provide all application functionality external to the server itself. Using experience gained in developing the BSCW Shared Workspace system, we argue that this "API-based" approach is both too restrictive and too "heavyweight" for the needs of many applications, which often require a small subset (or a different implementation) of the features the server offers. In contrast, we propose a more modular, component-based approach to enable applications for the World Wide Web, and present a prototype implementation of an integration toolkit which demonstrates this. As well as the potential for greater flexibility, performance and smaller application size, this approach also naturally extends to other methods of access and interaction such as electronic mail.

This paper presents an environment support for developing distributed applications (ESDDA) in the form of a library. It supports programming through shared objects. The environment provides a collection of predefined classes through which users can instantiate objects that can be accessed from any machine transparently in a distributed network environment. The classes refer to common data structures such as queues, stacks and bags. They provide an interface for creating, using and manipulating object instances. ESDDA offers as well a mechanism in which programmer can create objects (not shared) that can be accessed from remote clients.

Workshop on Computer Science and Information Technologies CSIT'99, Moscow, Russia, 1999 ... A Shared Object Environment for Developing Distributed ... Zair Abdelouahab Francisco José da Silva e Silva ... Department of Electrical Engineering, Department of Electrical ...

The ubiquity of Web browsers makes them an ideal generic front end for simple client-server systems. A very suitable area of application is controlling embedded systems, such as network printers, where supporting standard Web browsers is a cost-effective and convenient alternative to developing custom client software for remote administration from different platforms. This paper describes the design and implementation of a flexible communication server to be run directly on the embedded system. It supports different protocols to allow remote access, including HTTP. Thus, the embedded system can be accessed with any Web browser. Its state is represented as a set of Web pages containing dynamically generated information. Java applets included in these Web pages can connect back to the server to subscribe to live data feeds for real-time visualization of the embedded system's state. A GUI builder implemented as a Java applet can be used to customize the visual appearance of these applets.

The introduction of Java has been heralded as a revolution in network computing. Certainly, machine and operating system independent applets ittering through the Internet promised to jazz up web sur ng; but could they be used to advantage for distributed computing? The authors had encountered substantial problems in implementing a distributed revision control system, called WWRC, based on passive Web browsers. Java seemed to o er solutions to these problems. To this end, the authors have developed WWCM, a successor to WWRC written in Java. WWCM extends the concepts of WWRC to distributed con guration management by using CME|a new con guration management API. WWCM demonstrates that most of the design di culties encountered with WWRC can be solved with Java. Furthermore, WWCM o ers a test bed for a con guration management paradigm called template regulated alternative development. ? The authors addresses are (jjh|lamers|reuterj|tichy)@ira.uka.de respectively Like all prototypes, WWRC was designed to prove a concept. It illuminates not only the strength of using the Web for such tools, but also its weaknesses. The authors will demonstrate that many of these weaknesses can now be eliminated. Based on the experience with WWRC, the authors have built a new system, called World Wide Con guration Management (WWCM). By combining the strengths of the WWW, Java, TM and a new con guration management API, the authors will show that practical distributed software development tools can now be produced that are independent of the underlying hardware and operating system. Speci cally, WWCM provides distributed con guration management over standard Java capable Web browsers.

— To build complete and complex distributed platform, researchers are used to applying standards that facilitate sharing information as well as distributed service-oriented architectures that provide reuse and interoperability by means of component integration. These concepts lead us to a communication system that will allow us to implement tools that give full support to the management of IT GRC processes, taking advantage of the synergy effect created by the integration of the different components. Thus, throughout this article we analyze the proposals from the most relevant consortia concerned with communication system standards. This analysis will demonstrate that the use of standardized middleware technologies can limit the reuse and interoperability. Then, we will show a proposal which tries to solve this shortfall, using a blackboard-based architecture for integrating and communicating heterogeneous distributed components within an IT GRC platform.

... vi Page 7. Acknowledgments Before actually starting to work on the XploRe Quantlet Client/Server project, and this thesis itself, acknowledgments in papers often seemed some-how strange to me. ... 4 2 Client/Server Computing 7 2.1 Client/Server Computing - A Closer Look . . ...

Although on the one hand the Web has made a large amount of information easy to access for a great number of users, on the other it does not o er any simple mechanisms to facilitate the use of a calculation application on the Internet. Recently, however, Java has been developed, a new language de ned by Sun whose features make it ideal for the development of network applications. In this paper we show how it is possible to use this technology to create a network computing platform for the Web sharing of applications which were not speci cally devised for network use. The platform developed is also equipped with adequate security mechanisms which provide authentication services and, if required encryption. The approach proposed has been applied to porting the Sharpe tool (Symbolic Hierarchical Automated Reliability/Performance Evaluator) onto the Web.

The original Web did not support multiuser, interactive applications. This shortcoming is being studied, and several approaches have been proposed to use the Web as a platform for programming Internet applications. However, most existing approaches are oriented to centralized applications at servers, or local programs within clients. To overcome this deficit, we introduce PageSpace, that is a reference architecture for designing interactive multiagent applications. In this paper we describe how we control agents in PageSpace, using variants of the coordination language Linda to guide their interactions. Coordination technology is integrated with the standard Web technology and the programming language Java. Several kinds of agents live in the PageSpace: user interface agents, personal homeagents, agents that implement applications, and agents which interoperate with legacy systems. Within our architecture, it is possible to support fault-tolerance and mobile agents as well.

We introduce Jada, a programming toolkit for coordinating agents written in Java. Coordination among either concurrent threads or distributed Java objects is achieved via shared object spaces. By exchanging objects through object spaces, Java agents or applets can exchange data or synchronize their actions over the Internet, a LAN, a single host, or even inside a Java-enabled browser. The access to an object space is performed using a set of methods of an ObjectSpace object. Such operations inspired by the Linda language are powerful enough to solve several coordination problems. Moreover, we show how Jada can be used as a coordination kernel for more complex coordination architectures.

With the creation of computer networks in the 1970s came the birth of distributed network applications. Since then, there have been many applications that spanned multiple machines, but in the last 20 years no one created a serviceable network middleware package for developing highly effective distributed applications, that is, until now. This paper describes the design and architecture of T Spaces, a project at the IBM Almaden Research Center that fills the network middleware void. T Spaces embodies the three main characteristics of a useful mechanism for network programs, namely, data management, computation, and communication. Since it has the potential to connect any program to any other program on a computing network, T Spaces is an ideal platform on which to build a global computing services platform where any program or system service is available to any other program or service. In addition, its small footprint and Java™ implementation make T Spaces an ideal platform for writing distributed applications for embedded and palm-top computers, thus forging a needed gateway from the emerging embedded and palm-top computers to established desktop and server computers. 454 WYCKOFF ET AL.

Generative distributed open coordination systems have been so far implemented in a variety of ways. Surprisingly, no published implementation appears to address one particularly important issue for any general purpose open system | garbage collection.