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2003 | Buch

Invocation Protocol on Object Replicas Kapitel lesen Erstes Kapitel lesen

Cooperative Internet Computing

herausgegeben von: Alvin T. S. Chan, Stephen C. F. Chan, Hong Va Leong, Vincent T. Y. Ng

Verlag: Springer US

Buchreihe : The International Series in Engineering and Computer Science

Enthalten in: Professional Book Archive

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The Second International Workshop on Cooperative Internet Computing (CIC2002) has brought together researchers, academics, and industry practitioners who are involved and interested in the development of advanced and emerging cooperative computing technologies. Cooperative computing is an important computing paradigm to enable different parties to work together towards a pre­ defined non-trivial goal. It encompasses important technological areas like computer supported cooperative work, workflow, computer assisted design and concurrent programming. As technologies continue to advance and evolve, there is an increasing need to research and develop new classes of middlewares and applications to leverage on the combined benefits of Internet and web to provide users and programmers with highly interactive and robust cooperative computing environment. It is the aim of this forum to promote close interactions and exchange of ideas among researchers, academics and practitioners on the state-of-the­ art researches in all of these exciting areas. We have partnered with Kluwer Acedamic Press this year to bring to you a book compilation of the papers that were presented at the CIC2002 workshop. The importance of the research area is reflected both in the quality and quantity of the submitted papers, where each paper was reviewed by at least three PC members. As a result, we were able to only accept 14 papers for full presentation at the workshop, while having to reject several excellent papers due to the limitations of the program schedule.

Inhaltsverzeichnis

Frontmatter

Distributed Objects and Videos

Frontmatter
Chapter 1. Invocation Protocol on Object Replicas
Abstract
Objects are replicated in order to increase reliability and availability of an object-based system. Each method t is invoked on a subset of the replicas which is named quorum of t. Suppose each instance of t on the replicas invokes another method u on an object y. Since each instance of the method t invokes the method u, the method u is performed multiple times on the object of y. Here, the object y gets inconsistent This is redundant invocation. In addition, if each instance of the method t issues a request u to its quorum, more number of the replicas are manipulated than the quorum number of the method u. This is quorum expansion. We discuss a protocol to invoke methods on replicas in a nested manner where the redundant invocation and quorum expansion are resolved. We evaluate the protocol on how many replicas are manipulated and requests are issued.
Kenichi Hori, Makoto Takizawa, Michel Raynal
Chapter 2. Mobile Agent Model for Fault-Tolerant Objects Systems
Abstract
Application programs are required to be fault-tolerant as well as servers in order to make a system fault-tolerant. There are many discusses on how to make servers fault-tolerant, i.e. replication and checkpointing. Applications are also required to be fault-tolerant in order to realize fault-tolerant systems. In this paper, we take a mobile agent approach to realizing applications on multiple servers. Agents move around servers whose objects are manipulated. In traditional systems, application programs do not work if application servers are faulty. If the server is faulty, the agent finds an-other server where the agent can be performed. In addition, agents are replicated. Replicas of agents can move to servers even if a replica of the agent is faulty. Thus, applications can be fault-tolerant.
Takao Komiya, Makoto Takizawa
Chapter 3. A Multi-Paradigm Video Querying System over the Web
Architecture and Mechanisms
Abstract
Video data management over the Web is fast becoming one of the seminal topics for modern multimedia information systems. In this chapter we present an architecture of a multi-paradigm video querying system, along with its Web-based mechanisms that can offer a number of important features. To address the practical factors and concerns (such as resource cost and/or intellectual property concerns), video descriptions are separated from the raw/source video files. For better accessibility and interoperability, we adopt XML technology to make our system standard compatible (or XML-powered). In particular, the video description is extracted from the underlying storage (OODB) system, and the query result is sent back to the client as XML data description. As a result, our system can provide an efficient query server and support heavyweight clients. A prototype system manifesting these features has been developed based on OMG-CORBA and an object-oriented database engine.
Shermann S. M. Chan, Qing Li

Web and E-commerce

Frontmatter
Chapter 4. Building a Collaborative Client-Server Application
Abstract
This paper explores the issues and the techniques of enabling multimedia applications for the thin client computing. A technique for enhancing viewing capabilities of Web-based clients, called the Superior Plug-in Module (SPM), is proposed. By utilizing the collaborative client-server architecture, jobs are shifted from thin clients to a supporting server, thus reducing the computing overhead required by the clients. The supporting server performs transcoding operations while acting as a proxy at the same time, thus alleviating loads of the Web-based clients. Also note that it is not necessary to install additional software modules on clients equipped with the SPM, when new document types are introduced. This feature results in great benefits for the SPM technique over typical ones. Since there do exist some tradeoffs between the complexity, the efficiency and the scalability of this technique, two alternative scenarios simulating different real situations are constructed. Experimental studies conducted in the two scenarios show promising results of this work.
Wei-Guang Teng, Peter M. C. Chen, Ming-Syan Chen
Chapter 5. Acceleration of Data Center-Hosted Distributed Database-driven Web Applications
Abstract
Response time is essential to many Web applications. Consequently, many database-driven Web applications rely on data centers that host applications and database contents. Such IT infrastructure enables generation of requested pages at locations much closer to the end-users, thus reducing network latency. However, it incurs additional complexity associated with database/data center synchronization and data freshness. In this paper, we describe the deployment of NEC's CachePortal dynamic content caching technology on a database-driven Web site in a data center-based distribution infrastructure. The new system architecture has been experimentally evaluated and the results show that the deployment of NEC's CachePortal accelerates the dynamic content delivery up to 7 times while attaining a high level of content freshness.
Wen-Syan Li, Oliver Po, Wang-Pin Hsiung, K. Selcuk Candan, Divyakant Agrawal
Chapter 6. Multi-tiered Cache Management for E-Commerce Web Sites
Abstract
Response time is a key differentiation point among electronic commerce (e-commerce) applications. For many e-commerce applications, Web pages are created dynamically based on the current state of a business stored in database systems. To improve the response time, many e-commerce Web sites deploy caching solutions for acceleration of content delivery. There are multiple tiers in the content delivery infrastructure where cache servers can be deployed, including (1) data caching (in data centers), (2) content page caching (in edge or frontend caches), (3) database query result set caching (between application servers and DBMS). The architecture of database-driven e-commerce Web sites is more complex than that of typical Web sites. It requires the integration of Web servers, application servers, and back-end database systems as well as dynamic content caching solutions. In this paper, we study issues associated with management of content page caching and database query result set caching tiers. We observe that caching management for these two tiers have their unique characteristics. It is because cached object types and information available for the caching management in the two tiers are different. We propose solutions for effective caching management for each tier and conduct extensive evaluations. The experiment results show the usefulness of our technology in improving overall system performance.
Wang-Pin Hsiung, Wen-Syan Li, K. Selçuk Candan, Divyakant Agrawal
Chapter 7. A Flexible Payment Scheme and Its User-Role Assignment
Abstract
A flexible payment scheme and its user-role assignments are proposed in this paper. The scheme uses electronic cash for payment transactions. In this new protocol from the viewpoint of banks, consumers can improve anonymity if they are worried about disclosure of their identities. A new role called anonymity provider agent (AP) provides a high anonymous certificate. The role AP certifies re-encrypted data after verifying the validity of the content from consumers, but with no private information of the consumers required. With this new method, each consumer con get a required anonymity level, depending on the available time, computation mid cost.
There are two types of problems that may arise in user-role assignments. One is related to authorization granting process. Mutually exclusive roles may be granted to a user and the user may have or derive a high level of authority. Another is related to authorization revocation. When a role is revoked from a user, the user may still have the role from other roles. To solve these problems, we first analyze the duty separation constraints of the roles and role hierarchies in the scheme, then discuss granting a role to a user, weak revocation and strong revocation for the scheme.
Hua Wang, Yanchun Zhang, Jinli Cao

XML and Query Processing

Frontmatter
Chapter 8. Performance of Networked XML-Driven Cooperative Applications
Abstract
Web services are an emerging software technology that employ XML, e.g., W3C’s SOAP [1], to share and exchange data. They are a building block of cooperative applications that communicate using a network, they may serve as wrappers for legacy data sources, integrate multiple remote data sources, filter information by processing queries (function shipping), etc. Web services are based on the concept of “software and data as a service”. With those that interact with an end user, a fast response time is the difference between the following two scenarios: (1) users issuing requests, retrieving their results, and visiting the service repeatedly, and (2) users issuing requests, waiting for response and walking away prior to retrieving their results, with a lower likelihood of issuing future requests for this web service. One may employ a middleware to enhance performance by minimizing the impact of transmission time. This is accomplished by compressing messages. This paper identifies factors that this middleware must consider in order to reduce response time. In particular, it must ensure the overhead of compression (increased CPU time) does not exceed its savings (lower transmission time).
Shahram Ghandeharizadeh, Christos Papadopoulos, Min Cai, Krishna K. Chintalapudi
Chapter 9. Improved Parallel Algorithms for Path Expression Query Processing of Semi-Structured Data
Abstract
Semi-structured data can be described by a labelled directed graph. The costs of processing path expression based queries on semi-structured data could be very high due to conventional graph traversals may be intensively involved. Parallel query processing is an attractive solution for improving system performance. In this paper four parallel path-based query process methods are introduced. The first three methods are parallel versions of pointer chasing methods based on the principles of message-driven computation. In the fourth method the pro-fetch technique is used to achieve a low communication cost and a high degree of parallelisation. The initial algorithm analyses are also presented.
Wenjun Sun, Kevin J. Lü, Kam Fai Wong
Chapter 10. INODE
An Enumeration Scheme for Efficient Storage of XML Data
Abstract
XML has become the standard for representing and exchanging information on Internet. This poses a challenge to efficiently store and query XML data. Several model-mapping approaches have been proposed to store XML data in relational database systems. The key features of model-mapping approach are that fixed database schemas are used for all XML documents and DTD information is not needed. In this paper, we present a new model-mapping approach, called INode. This approach is based on a numbering scheme for elements. It enables quick retrieval of parent-child and ancestor-descendant relationships between elements in the XML data graph. Experiments with two data sets and two query sets show that INode can reduce the storage requirement while having a better query performance.
Lau Hoi Kit, Vincent Ng

Modeling and Specification

Frontmatter
Chapter 11. Services for Virtual Teams Hosting
ToxicFarm Introduction
Abstract
Virtual teams provider is an emerging business on the Internet. It allows people to work together distributed across space, time and organizations. This paper overviews and discusses a set of generic services requested to host a virtual team. These services and their integration are illustrated thanks to the ToxicFarm environment developed by the authors.
F. Charoy, C. Godart, P. Molli, G. Oster, M. Patten, M. Valdes
Chapter 12. Towards a Transactional Framework Derived from Real Workflows
Abstract
One fundamental issue that has yet to he adequately addressed in loosely coupled distributed systems is long duration transactions — maintaining integrity of the system in the presence of both failures and concurrent activities for processes that last from seconds to years. This issue is of particular importance to both business-to-business integration (B2Bi) and enterprise application integration (EAI) applications such as e-procurement.
Numerous transaction models have been proposed in the past to address this issue. They include transactions with ACID (Atomicity, Consistency, Isolation and Durability) properties designed for short duration transactions (lasting milliseconds), compensation transactions and other advanced/extended transaction models. For varying reasons such as performances, expressiveness and appropriateness, existing transaction models do not meet general requirements for long duration transactions in loosely coupled distributed systems especially B2Bi and EAI applications.
This position paper has two main objectives. First, we describe an
application that is based on a real e-procurement scenario and discuss its transactional requirements. In the discussion, we highlight why some existing advanced/extended transaction model fail to provide adequate transactional support for this particular application. Second, we informally describe an expressive framework that captures, declaratively, the transactional requirements of long duration transaction.
Dean Kuo, Alan Fekete, Paul Greenfield, Julian Jang
Chapter 13. Web-Services Coordination Model
Abstract
Web-services are self-contained, self-describing modular applications and can be soon as a newly emerging distributed computing model for the Web. There are two types of web-services: atomic and composite. A composite Web-Service can be described as a directed process graph that composes other atomic or composite Web-Services. A graph defines the order of execution among the nodes in the process model. In this paper we first discuss the relevant research issues required for outlining a web-service coordination model and compare them to existing coordination models. Furthermore we provide an e-learning scenario where we experiment with a team-enabled workflow management system to enact workflow-based web-services.
Karim Baïna, Schahram Dustdar
Chapter 14. Hierarchical Text Classification Methods and Their Specification
Abstract
Hierarchical text classification refers to assigning text documents to the categories in a given category tree based on their content. With large number of categories organized as a tree, hierarchical text classification helps users to find information more quickly and accurately. Nevertheless, hierarchical text classification methods in the past have often been constructed in a proprietary manner. The construction steps often involve human efforts and are not completely automated. In this chapter, we therefore propose a specification language known as HCL (Hierarchical Classification Language). HCL is designed to describe a hierarchical classification method including the definition of a category tree and training of classifiers associated with the categories. Using HCL, a hierarchical classification method can be materialized easily with the help of a method generator system.
Aixin Sun, Ee-Peng Lim, Wee-Keong Ng
Backmatter
Metadaten
Titel
Cooperative Internet Computing
herausgegeben von
Alvin T. S. Chan
Stephen C. F. Chan
Hong Va Leong
Vincent T. Y. Ng
Copyright-Jahr
2003
Verlag
Springer US
Electronic ISBN
978-1-4615-0435-1
Print ISBN
978-1-4613-5075-0
DOI
https://doi.org/10.1007/978-1-4615-0435-1