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Cooperation among systems has gained substantial importance in recent years: electronic commerce virtual enterprises and the middleware paradigm are just some examples in this area. CoopIS is a multi-disciplinary conference, which deals with all aspects of cooperation. The relevant disciplines are: collaborative work, distributed databases, distributed computing, electronic commerce, human-computer interaction, multi-agent systems, information retrieval, and workflow systems. The CoopIS series provides a forum for well-known researchers who are drawn by the stature and the tradition of these conference series and has a leading role in shaping the future of the cooperative information systems area. CoopIS 2000 is the seventh conference in the series and the fifth conference organized by the International Foundation on Cooperative Information Systems (IFCIS). It is sponsored by the IFCIS, the IBM Research Laboratory in Haifa and Compaq, Tandem labs Israel. It replaces the former international workshops on Interoperability in Multidatabase systems (IMS) and the conference series on Cooperative Information Systems (CoopIS & ICICIS). In response to the call for papers 74 papers were submitted. Each of them was reviewed by at least three reviewers, and at the end of this process 24 papers were accepted for presentation at the conference. Six additional papers were selected for short presentations. In addition the conference includes two panels, two keynote speakers (Professor Calton Pu from Georgia Tech and Professor Sheizaf Rafaeli from Haifa University) and one tutorial. A special issue of the International Journal of Cooperative Information Systems will follow. August 2000 Opher Etzion & Peter Scheuermann



Workflow Modeling

Formalizing (and Reasoning about) the Specifications of Workflows

We address the problem of workflow requirements specifications under realistic assumptions that it involves experts from different domains (different business policies), where not all the possible execution scenarios known beforehand. Using recent results on reasoning about actions, we formalize the notion of the specifications’ correctness. To address this, we propose a high level language \(\mathcal{A_W}\) as a basis of our prototype tool for process specification. We go “step” before actual analysis and design, and offer a formalism which enables the experts to specify their knowledge in terms of the effects that the activities have on the workflow environment. Our methodology allows expressing not only the knowledge, but also the “ignorance” (the semantics allows unknown values to reflect a realistic situation of agents dealing with incomplete information) and the possibility of exceptional situations. We define an entailment relation which enables reasoning about the correctness of the specifications, in terms of achieving a desired goal, and testing about consequences of modifications in the workflow descriptions.
Goce Trajcevski, Chitta Baral, Jorge Lobo

Advanced Workflow Patterns

Conventional workflow functionality like task sequencing, split parallelism, join synchronization and iteration have proven effective for business process automation and have widespread support in current workflow products. However, newer requirements for workflows are encountered in practice, opening grave uncertainties about the extensions for current languages. Different concepts, although outwardly appearing to be more or less the same, are based on different paradigms, have fundamentally different semantics and different levels of applicability – more specialized for modeling or more generalized for workflow engine posit. By way of developmental insight of new requirements, we define workflow patterns which are described imperatively but independently of current workflow languages. These patterns provide the basis for an in-depth comparison of 12 workflow management systems. As such, the work reported in this paper can be seen as the academic response to evaluations made by prestigious consulting companies. Typically, these evaluations hardly consider the workflow modeling language and routing capabilities and focus more on the purely technical and commercial aspects.
W. M. P. van der Aalst, A. P. Barros, A. H. M. ter Hofstede, B. Kiepuszewski

Extending UML with Workflow Modeling Capabilities

Nowadays application systems are modeled in object-oriented design languages like the Unified Modeling Language (UML). Although workflow management has to deal with such environments, typically propriatory modeling languages are used. We try to remedy the use of seperate languages by proposing an extension of the UML to allow workflow modeling, thereby providing a seamless integration of workflow functionality in object-oriented application systems.
Guido Wirtz, Mathias Weske, Holger Giese

Information Retrieval

ConSearch: Using Hypertext Contexts as Web Search Boundaries

This paper describes a schema for searching on the Web by making use of hypertext contexts that can be represented with new Web standards as search boundaries and argues that this would help to provide users more accurate results in their searches concerning specific topics or subject domains. It also proposes several issues to be addressed in making the schema applicable and presents a prototype system that addresses these issues and supports hypertext context-based search.
Zhanzi Qiu, Matthias Hemmje, Erich J. Neuhold

Combining the Power of Searching and Querying

EquiX is a search language for XML that combines the power of querying with the simplicity of searching. Requirements for search languages are discussed and it is shown that EquiX meets the necessary criteria. Both a graphical abstract syntax and a formal concrete syntax are presented for EquiX queries. In addition, the semantics is defined. It is shown that EquiX has an evaluation algorithm that is polynomial under combined complexity.
EquiX combines pattern matching, quantification and logical expressions to query both the data and meta-data of XML documents. The result of a query in EquiX is a set of XML documents. A DTD describing the result documents is derived automatically from the query.
Sara Cohen, Yaron Kanza, Yakov Kogan, Werner Nutt, Yehoshua Sagiv, Alexander Serebrenik

Cooperative Indexing, Classification, and Evaluation in BoW

BoW is an on-line bibliographic Dynamic Ranked Informationspace (DyRI). It provides the infrastructure for users to add bibliographical information, classify it, index it, and evaluate it. Thus users cooperate by contributing and sharing their experience in order to advance the most problematic aspects of information retrieval: finding the most relevant and high quality information for their needs.
Dror G. Feitelson

Cooperative Databases

Complex View Selection for Data Warehouse Self-Maintainability

A Data warehouse (DW) integrates data from multiple distributed heterogeneous data sources. A DW can be seen as a set of materialized views defined over the source relations. The materialized views are eventually updated upon changes of the source relations. For different reasons (e.g. reduction to the view maintenance cost, unavailability of the sources etc) it is desirable to make the DW self-maintainable. This means that the materialized views can be maintained, for every source relation change, without accessing the sources.
In this paper we deal with the problem of selecting auxiliary views to materialize in the DW such that the original materialized views and the auxiliary views taken together are self-maintainable. A distinguishing feature of our approach is that we consider that a data source can store multiple source relations referenced by the materialized views. Further, the data sources are of cooperative type, that is, they can compute and transmit to the DW the changes for (complex) views defined over their own relations. We first formally model the problem by using an AND/OR dag structure for multiple views that allows the representation of common subexpression sharing. We then provide a method for computing auxiliary views that fit in the space available for materialization and minimize the cost of computing the changes to be applied to the materialized views during the maintenance process.
Dimitri Theodoratos

Integrating Snapshot Isolation into Transactional Federations

This Paper reconsiders the Problem of transactional federations, more specifically the concurrency control issue, with particular consideration of component Systems that provide only snapshot isolation, which is the default setting in Oracle and widely used in practice. The Paper derives criteria and practical protocols for guaranteeing global serializability at the federation level. The Paper generalizes the well-known ticket method and develops novel federation-level graph testing methods to incorporate sub-serializability component Systems like Oracle. These contributions are embedded in a practical project that built a CORBA-based federated database architecture suitable for modern Internet- or Intranet-based applications such as electronie commerce. This prototype System, which includes a federated transaction manager coined Trafic (Transactional Federation of Information Systems Based on CORBA), has been fully implemented with support for Oracle and O2 as component Systems and using Orbix as federation middleware. The Paper presents Performance measurements that demonstrate the viability of the developed concurrency control methods.
Ralf Schenkel, Gerhard Weikum

An Evaluation of the Java-Based Approaches to Web Database Access

Given the undeniable popularity of the Web, providing efficient and secure access to remote databases using a Web browser is crucial for the emerging cooperative information systems and applications. In this paper, we evaluate all currently available Java-based approaches that support persistent connections between Web clients and database servers. These approaches include Java applets, Java Sockets, Servlets, Remote Method Invocation, CORBA, and mobile agents technology. Our comparison is along the dimensions of performance and programmability.
Stavros Papastavrou, Panos Chrysanthis, George Samaras, Evaggelia Pitoura

Short Presentations

A Framework for ASP-Marketplaces

For organizations that plan to use online software applications via Internet one of the most important questions is, ”How do you choose the right ASP for the companies corporate needs?”. ASP marketplaces offer a plurality of pricing models and different levels of service. From whole system and whole service to single applications and methods, every digital product and service can be provided through an ASP marketplace. There is a need for ASP marketplaces, which gives the user a transparent insight into the ASP market. In this paper we define Application Service Providing in the context of Outsourcing. Then we analyze relevant software classes for ASP marketplaces. Finally we will set criteria to compare different levels of service of ASP marketplace. This paper gives an overview of key characteristics ASP marketplace provider must take into account by preparing the business process in order to successfully deliver application services.
Gerrit Tamm, Oliver Günther

Exploring the Semantic Structure of Technical Document Collections: A Cooperative Systems Approach

Identifying and analyzing the knowledge available in document form is a key element of corporate knowledge management. In engineering-intensive organizations, it involves tasks such as standard generation and evaluation, comparison of related cases and experience reuse in their treatment. In this paper, we present the design, implementation, and some application experiences with a modular approach that allows a variety of techniques from semantic document analysis to interoperate with a tailorable map-centered visualization of the structure of technical document collections.
Andreas Becks, Stefan Sklorz, Matthias Jarke

Organized Distributed Systems

We describe an approach to the specification of distributed systems that exhibit complex behavior in dynamic environments. We present a model of decision making in artificial organizations that derives inspiration from Organization and Management Theory and from Multi- Agent Systems research. We argue that this approach aids the system designer by supporting a suitably high level of abstraction in the design process.
Gil Tidhar, Elizabeth A. Sonenberg

Managing Aging Data Using Persistent Views

Enabled by the continued advances in storage technologies, the amounts of on-line data grow at a rapidly increasing Pace. For example, this development is witnessed in the so-called data webhouses that accumulate data derived from clickstreams. The presence of very large and continuously growing amounts of data introduces new challenges, one of them being the need for effectively managing aging data that is perhaps inaccurate, partly outdated, and of reduced interest. This Paper describes a new mechanism, persistent views, that aids in flexibly reducing the volume of data, e.g., by enabling the replacement of such “low-interest ,” detailed data with aggregated data; and it outlines a strategy for implementing persistent views.
Janne Skyt, Christian S. Jensen

A Workflow System through Cooperating Agents for Control and Document Flow over the Internet

In this paper we describe an architecture that provides for automating and monitoring the flow of control and document over the Internet among different organizations, thereby creating a platform necessary to describe higher order processes involving several organizations and companies. The higher order process is designed through a graphical user interface and is executed through cooperating agents that are automatically initialized at each site that the process executes. Agents handle the activities at their site, provide for coordination with other agents in the system by routing the documents in electronic form according to the process description. The system is capable of activating external applications (which may be inside the company firewall) when necessary, keeping track of process information, and providing for the security and authentication of documents as well as comprehensive monitoring facilities. The architecture is general enough to be applied to any business practice where data flow and invocation of activities among different industries and cooperations follow a pattern that can be described through a process definition, however since the project is on maritime industry, some of the graphical user interfaces are customized accordingly. The system is fully operational for industrial use.
A. Dogac, Y. Tambag, A. Tumer, M. Ezbiderli, N. Tatbul, N. Hamali, C. Icdem, C. Beeri

Distributed View Expansion in Composable Mediators

Data integration on a large scale poses complexity and performance problems. To alleviate the complexity problem we use a modular approach where many heterogeneous and distributed data sources are integrated through composable mediators. Distributed mediators are defined as object-oriented (OO) views defined in terms of views in other sub-mediators or data sources. In order to minimize the performance penalty of the modular approach we have developed a distributed expansion strategy for OO views where view definitions are selectively imported from sub-mediators. Our performance analysis has shown that the distributed view expansion can support modularity through distributed and composable mediators with little overhead.
Timour Katchaounov, Vanja Josifovski, Tore Risch

Information Services

eResponder: Electronic Question Responder

With the complexity of systems increasing, support centers are flooded with questions submitted by e-mail, by Web, or by phone. This paper describes eResponder, a system which provides an integrated solution for automatic responses to user questions. eResponder stores question and answer pairs that have previously been asked. These pairs can be used to either provide an immediate response to user questions, or to assist customer service representatives in drafting new responses to similar questions or to yet unanswered questions. Users submit free text questions to the system via one unified interface. When a new question arrives, the system searches its databases for similar questions as well as for relevant answers and finds the most relevant Q&A pair based on both these measures. eResponder provides a relevance feedback mechanism and an answer summarizer to assist CSR’s in creating new responses. The results of an experiment conducted to evaluate the system performance show that the combination of independent question and answer scores yields high precision search results.
David Carmel, Menachem Shtalhaim, Aya Soffer

Efficient Matching for Web-Based Publish/Subscribe Systems

There is a need for systems being able to capture the dynamic aspect of the web information by notifying users of interesting events. Content-based publish/subscribe systems are an emerging type of publish/subscribe systems where events are filtered according to their attribute values, using filtering criteria defined by the subscribers, and then sent to the interested subscribers. Compared to traditional publish/subscribe systems, content-based systems offer more subscription expressiveness. The cost of this gain in expressiveness is an increase in the complexity of the matching process: the more sophisticated the constructs, the more complex the matching process. In this paper, we present an efficient and scalable solution to the matching problem. We also present a semi-structured event model which is well suited for the information published on the Web, and flexible enough to support easy integration of publishers.
João Pereira, Françoise Fabret, François Llirbat, Dennis Shasha

A Software Retrieval Service Based on Knowledge-Driven Agents

The ability of retrieving and installing software in an easy and efficient way confers competitive advantage on computer users in general, and even more especially on mobile computer users. In this paper we present a software retrieval service that allows mobile users to select, retrieve and install software anywhere and at any time. This service makes use of agents that allow 1) a browsing of a software ontology automatically customized to different kind of users and user computers; 2) an efficient retrieval of the selected software; and 3) an automatic update of the available software ontology. A software obtaining process based on agents, that manage semantic descriptions of available software, presents a qualitative advance with respect to existing solutions where users must know the location and access method of various remote software repositories.
E. Mena, A. Illarramendi, A. Goñi

Workflow Execution

Benchmarking and Configuration of Workflow Management Systems

Workflow management systems (WFMS) are a cornerstone of mission-criticial, possibly cross-organizational business processes. For large-scale applications both their performance and availability are crucial factors, and the system needs to be properly configured to meet the application demands. Despite ample work on scalable system architectures for workflow management, the literature has neglected the important issues of how to systematically measure the performance of a given system configuration and how to determine viable configurations without resorting to expensive trial-and-error or guesswork. This paper proposes a synthetic benchmark for workflow management systems; based on the TPC-C order-entry benchmark, a complete e-commerce workflow is specified in a system-independent form. This workflow benchmark, which stresses all major components of a workflow system and is parameterized in a flexible manner, has been applied to two operational systems, the commercial system Staffware97 and our own prototype system Mentor-lite. The paper reports performance results from our measurements and discusses lessons learned. In particular, the results demonstrate the scalability of the Mentor-lite architecture. The measurements also underline the need for configuring systems intelligently, and the paper outlines an auto-configuration tool that we have been building to this end.
Michael Gillmann, Ralf Mindermann, Gerhard Weikum

Workflow Modeling using Proclets

The focus of traditional workflow management systems is on control flow within one process definition, that describes how a single case (i.e., work-flow instance) is handled in isolation. For many applications this paradigm is inadequate. Interaction between cases is at least as important. This paper introduces and advocates the use of interacting proclets, i.e., light-weight workflow processes. By promoting interactions to first-class citizens, it is possible to model complex workflows in a more natural manner, with improved expressive power and flexibility.
W. M. P. van der Aalst, P. Barthelmess, C. A. Ellis, J. Wainer

Dealing with Logical Failures for Collaborating Workflows

Logical failures occurring during workflow execution require the dynamic adaptation of affected workflows. The consequences such a dynamic adaptation may have for collaborating workflows have not yet been investigated sufficiently. We propose a rule-based approach for dynamic workflow adaptation to deal with logical failures. In our approach, workflow collaboration is based on agreements specifying the delivery time and quality of objects a workflow expects from its collaboration partners. Our mechanisms decide which collaborating workflows have to be informed when a dynamic adaptation is performed. In particular, we estimate the temporal and qualitative implications a dynamic adaptation has for collaboration partners. Because of the automated handling of logical failures, we expect that our approach significantly improves the robustness and correctness of collaborating workflows. The approach has been developed in the context of collaborative work-flow- based care for cancer patients.
R. Müller, E. Rahm

CSCW and Organizational Aspects

A Negotiation Model for CSCW

The aim of this Paper is to present our model for a generic and flexible negotiation Service and its implementation in Computer Supported Collaborative Work (CSCW) environments. Within a cooperative work environment, users naturally need negotiation support mechanisms to study possible alternatives in group decision making. The objective of our work is to build a negotiation model independent of any particular application field. Contrary to studied models, our model focuses on formalizing the negotiation from three Points of view: exchanged information between the agents to negotiate (the language), the way this information is exchanged (the protocol) , and the internal behavior of an agent (the tactics). In addition to a Separation of the Problems involved in each one of these three facets of the negotiation, this approach allows also a greater flexibility than traditional Systems dedicated to one kind of Problems. We Chose to use a transactional approach based on Speech acts to develop our axiom based negotiation model which has been implemented as a negotiation Service in our CSCW environment DisCOO [l, 2]. After the tackled Problem presentation, we will expose the state of the art, then the proposed negotiation formal model, and, finally, the implementation.
Manuel Munier, Karim Baïna, Khalid Benali

The Organizational Memory Information System PRINCE

Business process management has become an area of increasing interest in the last years. However, the acquisition of the information about business processes itself becomes a complex task since this information is spread over different people, quite often is inconsistent, and often is only available implicitly in the minds of the people involved in the processes. Within this paper we describe our work on a cooperative information system PRINCE serving as an organizational memory information system. The goal of the system is to support the systematic management of business processes capturing process information, structuring it, and preserving it in a way to be used during the different phases of a process management lifecycle. The system is able to manage information of different multimedia object types (such as text, audio and video documents). It can be used by different users giving dedicated access rights (both for filling and retrieving information). Since the information base is cooperatively filled by different users several mechanisms like consistency/ inconsistency indication, information abonements etc. have been introduced for managing the huge amount of information.
Arndt Kuhlmann, Wolfgang Deiters

An Extensible Business Communication Language

A main problem for electronic commerce, particularly for business-to- business applications, lies in the need for the involved information systems to meaningfully exchange information. Domain-specific standards may be used to define the semantics of common terms. However, in practice it is not easy to find those domain-specific standards that are detailed and stable enough to allow for real interoperability. Therefore, we propose an architecture that allows for incremental construction of a shared repository including a multilingual thesaurus, which is used in a business communication language. Communicating information systems then refer to the common thesaurus while exchanging messages. Our emphasis is be on separating semantics (in the thesaurus) and syntax (in XML). Therefore, our extensibility is not only that of XML, but also the extensibility of the semantics that is modeled in the shared repository.
The business communication language XLBC is presented and how it can be used in electronic commerce applications. XLBC message patterns and conversation protocols are stored in the shared repository as well.
Hans Weigand, Wilhelm Hasselbring

Mobile Cooperation

Exploiting the Features of Asymmetry for Query Processing in a Mobile Computing Environment

With the cutting edge technology advance in wireless and mobile computers, the query processing in a mobile environment involves join processing among different sites which include static servers and mobile computers. Because of the need of energy saving and also the presence of asymmetric features in a mobile computing environment, the conventional query processing for a distributed database cannot be directly applied to a mobile computing system. In this paper, we first explore three asymmetric features of a mobile environment. Then, in light of these features, we devise query processing schemes. Performance of these query processing schemes is comparatively analyzed and sensitivity analysis on several parameters is conducted.
Wen-Chih Peng, Ming-Syan Chen

Data Lockers: Mobile-Agent Based Middleware for the Security and Availability of Roaming Users Data

Accessing remote data anywhere and at anytime constitutes an important advantage in many business environments. However, when working with mobile devices, users face many problems related to: (1) device restrictions: mobile devices are resource-constrained, more vulnerable and fragile than stationary devices (devise exposure problems) and, (2) the communication media: wireless communications are often unstable, asymmetric and expensive (media problems). To alleviate these problems, we present a service, the Lockers Rent Service, for keeping the data of mobile users in a secure and safe space in a proxy at the fixed network, thus providing a solution to the device exposure problems. Data stored in data lockers are available even when the mobile device is disconnected. Furthermore, specific tasks are carried out at the fixed network on behalf of the mobile user, in this way relieving the media problems. The architecture of the Locker Rent Service is based on mobile agents.
Yolanda Villate, Arantza Illarramendi, Evaggelia Pitoura

A Java Framework for Mobile Data Synchronization

An industry consortium has developed a Java framework for peer-to-peer synchronization of object stores on mobile devices. A device may issue or service requests for synchronization. Successful synchronization leaves replica stores in identical states. The framework is designed to accommodate memory-limited devices and unreliable and expensive connections. Stored objects belong to application classes with methods that are invoked by the framework during synchronization, for example to resolve update conflicts.
Norman H. Cohen

Multi Agents Systems

Dynamic Pricing with Limited Competitor Information in a Multi-Agent Economy

We study the price dynamics in a multi-agent economy consisting of buyers and competing sellers, where each seller has limited information about its competitors’ prices. In this economy, buyers use shopbots while the sellers employ automated pricing agents or pricebots. A pricebot resets its seller’s price at regular intervals with the objective of maximizing revenue in each time period. Derivative following provides a simple, albeit naive, strategy for dynamic pricing in such a scenario. In this paper, we refine the derivative following algorithm and introduce a model-optimizer algorithm that re-estimates the price-profit relationship for a seller in each period more efficiently. Simulations using the model-optimizer algorithm indicate that it outperforms derivative following even though it does not have any additional information about the market. Our results underscore the role machine learning and optimization can play in fostering competition (or cooperation) in a multi-agent economy where the agents have limited information about their environment.
Prithviraj Dasgupta, Rajarshi Das

Multi-agent Cooperative Transactions for E-Commerce

E-Commerce is a distributed computing environment with dynamic relationships among a large number of autonomous service requesters, brokers and providers. With the increasing automation of e-commerce applications, we will see the use of software agents that cooperate to perform business transactions. Multi-agent cooperative transactions are different in their requirements both from conventional atomic transactions executed under centralized control and from nested transactions executed under hierarchical control. Cooperative transactions require peer-to-peer protocols based on inter-agent communication. In this paper, we develop a cooperative mulit-agent transaction model that includes peer-to-peer protocols for commit control and failure recovery. The significance and feasibility of this approach have been demonstrated in a prototype implemented at HP Labs, using our dynamic agent infrastructure.
Qiming Chen, Umesh Dayal

Cross-Organizational Transaction Support for Virtual Enterprises

In recent years, workflow management systems have become an accepted technology to support automation in process-centric environments. Lately, organizations concentrate more and more on their core business processes while outsourcing supporting processes to other organizations, thereby forming virtual enterprises. To apply workflow management technology in these virtual enterprises, support for cross-organizational processes is necessary. Transaction support, already considered an important issue in intra-organizational workflow management systems, must be extended to deal with the cross-organizational aspects as well. This paper presents a high-level transaction model and architecture for cross-organizational workflow processes. Characteristic of the model is the flexibility in rollback semantics by combining rollback modes and rollback scopes, supported by a dynamically generated architecture that is configured conforming to an electronic contract that has been established between the different organizations. The transaction model and architecture are independent of the underlying workflow management system platform, however, in the CrossFlow project the presented technology is being implemented on top of IBM’s MQ Series Workflow.
Jochem Vonk, Wijnand Derks, Paul Grefen, Marjanca Koetsier


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