Herman Lam

Achieving dynamic inter-organizational workflow management by integrating business processes, events and rules

In the competitive global marketplace, business organizations often need to team up and operate as a virtual enterprise to achieve common business goals. Since the business environment of a virtual enterprise is highly dynamic, it is necessary to develop a workflow technology that is capable of handling dynamic workflows across enterprise boundaries. The paper describes a dynamic workflow model and a dynamic workflow management system for modeling and controlling the execution of inter-organizational business processes. The model extends the underlying model of WfMCs WPDL by adding connectors, events, triggers and rules as its modeling constructs, encapsulating activity definitions, and allowing e-service requests as a part of the activity specification. The workflow management system makes use of an event and rule server to trigger business rules during the enactment of workflow processes to enforce business constraints and policies and/or to modify the process model at run-time. It also provides a mechanism to dynamically bind e-service requests to e-services.

An Internet-based negotiation server for e-commerce

Abstract. This paper describes the design and implementation of a replicable, Internet-based negotiation server for conducting bargaining-type negotiations between enterprises involved in e-commerce and e-business. Enterprises can be buyers and sellers of products/services or participants of a complex supply chain engaged in purchasing, planning, and scheduling. Multiple copies of our server can be installed to complement the services of Web servers. Each enterprise can install or select a trusted negotiation server to represent his/her interests. Web-based GUI tools are used during the build-time registration process to specify the requirements, constraints, and rules that represent negotiation policies and strategies, preference scoring of different data conditions, and aggregation methods for deriving a global cost-benefit score for the item(s) under negotiation. The registration information is used by the negotiation servers to automatically conduct bargaining type negotiations on behalf of their clients. In this paper, we present the architecture of our implementation as well as a framework for automated negotiations, and describe a number of communication primitives which are used in the underlying negotiation protocol. A constraint satisfaction processor (CSP) is used to evaluate a negotiation proposal or counterproposal against the registered requirements and constraints of a client company. In case of a constraint violation, an event is posted to trigger the execution of negotiation strategic rules, which either automatically relax the violated constraint, ask for human intervention, invoke an application, or perform other remedial operations. An Event-Trigger-Rule (ETR) server is used to manage events, triggers, and rules. Negotiation strategic rules can be added or modified at run-time. A cost-benefit analysis component is used to perform quantitative analysis of alternatives. The use of negotiation servers to conduct automated negotiation has been demonstrated in the context of an integrated supply chain scenario.

Novo-G: At the Forefront of Scalable Reconfigurable Supercomputing

The Novo-G supercomputers architecture can adapt to match each application/s unique needs and thereby attain more performance with less energy than conventional machines. Reconfigurable computing can provide solutions for domain scientists at a fraction of the time and cost of traditional servers or supercomputers. As we describe here, the Novo-G machine, applications, research forum, and preliminary results are helping to pave the way for scalable reconfigurable computing.

Association algebra: a mathematical foundation for object-oriented databases

The application of the object-oriented (O-O) paradigm in the database management field has gained much attention in recent years. Several experimental and commercial O-O database management systems have become available. However, the existing O-O DBMSs still lack a solid mathematical foundation for the manipulation of O-O databases, the optimization of queries, and the design and selection of storage structures for supporting O-O database manipulations. This paper presents an association algebra (A-algebra) to serve as a mathematical foundation for processing O-O databases, which is analogous to the relational algebra used for processing relational databases. In this algebra, objects and their associations in an O-O database are uniformly represented by association patterns which are manipulated by a number of operators to produce other association patterns. Different from the relational algebra, in which set operations operate on relations with union-compatible structures, the A-algebra operators can operate on association patterns of homogeneous and heterogeneous structures. Different from the traditional record-based relational processing, the A-algebra allows very complex patterns of object associations to be directly manipulated. The pattern-based query formulation and the A-algebra operators are described. Some mathematical properties of the algebraic operators are presented together with their application in query decomposition and optimization. The completeness of the A-algebra is also defined and proven. The A-algebra has been used as the basis for the design and implementation of an object-oriented query language, OQL, which is the query language used in a prototype Knowledge Base Management System OSAM*.KBMS. >

Reconfigurable Fault Tolerance: A Comprehensive Framework for Reliable and Adaptive FPGA-Based Space Computing

Commercial SRAM-based, field-programmable gate arrays (FPGAs) have the potential to provide space applications with the necessary performance to meet next-generation mission requirements. However, mitigating an FPGA’s susceptibility to single-event upset (SEU) radiation is challenging. Triple-modular redundancy (TMR) techniques are traditionally used to mitigate radiation effects, but TMR incurs substantial overheads such as increased area and power requirements. In order to reduce these overheads while still providing sufficient radiation mitigation, we propose a reconfigurable fault tolerance (RFT) framework that enables system designers to dynamically adjust a system’s level of redundancy and fault mitigation based on the varying radiation incurred at different orbital positions. This framework includes an adaptive hardware architecture that leverages FPGA reconfigurable techniques to enable significant processing to be performed efficiently and reliably when environmental factors permit. To accurately estimate upset rates, we propose an upset rate modeling tool that captures time-varying radiation effects for arbitrary satellite orbits using a collection of existing, publically available tools and models. We perform fault-injection testing on a prototype RFT platform to validate the RFT architecture and RFT performability models. We combine our RFT hardware architecture and the modeled upset rates using phased-mission Markov modeling to estimate performability gains achievable using our framework for two case-study orbits.

Characterization of Fixed and Reconfigurable Multi-Core Devices for Application Acceleration

As on-chip transistor counts increase, the computing landscape has shifted to multi- and many-core devices. Computational accelerators have adopted this trend by incorporating both fixed and reconfigurable many-core and multi-core devices. As more, disparate devices enter the market, there is an increasing need for concepts, terminology, and classification techniques to understand the device tradeoffs. Additionally, computational performance, memory performance, and power metrics are needed to objectively compare devices. These metrics will assist application scientists in selecting the appropriate device early in the development cycle. This article presents a hierarchical taxonomy of computing devices, concepts and terminology describing reconfigurability, and computational density and internal memory bandwidth metrics to compare devices.

Constraint specification and processing in Web services publication and discovery

Much effort is being made by the IT industry towards the establishment of a Web services infrastructure and the refinement of its component technologies to enable the sharing of heterogeneous application resources. Traditional roles of the service provider, service requestor and service broker and their interactions are now being improved upon to enable more effective services. The implementation of the Web service broker is currently limited to being an interface to the service repository for service registration, browsing and/or programmatic access. In this work, we have extended the functionality of the Web services broker to include constraint specification and processing, which enables the broker to find a good match between a service providers capabilities and a service requestors requirements. This paper presents the extension made to the Web Services Description Language to include constraint specifications in service descriptions and requests, the architecture of a constraint-based broker, the constraint matching technique, some implementation details, and preliminary evaluation results.

An extensible knowledge base management system for supporting rule-based interoperability among heterogeneous systems

The main objective of a virtual enterprise (VE) is to allow a number of organizations to rapidly develop a working environment to manage a collection of resources contributed by the organizations toward the attainment of some common goals. One of the key requirements of a tirtua.1 enterprise is to develop an information infrastructure to sup port the interoperability of distributed and heterogeneous systems for controlling and conducting the business of the virtual enterprise. In order to achieve the objective and to meet this requirement, it is necessary to model all things of interest to a virtual enterprise such as data, human and hardware resources, organizational structures, business constraints, production processes, and activities in work management. Additionally, a system is needed to manage the meta-information and the shared data and to provide both build-time and run-time services to the heterogeneous systems to achieve their interoperability. In this paper, we describe the modeling requirements for a virtual enterprise and show how a global, mediated VE conceptual model can be constructed at build-time and be used by a knowledge base management system (KBMS) to provide run-time support for the operation of a virtual enterprise. The KBMS differs from the traditional database management system (DBMS) in that it provides not only the traditional database management services (such as persistent, object management, transaction management, etc.), but also a set of knowledge base management services. Most notably, the KBMS provides a request/event monitoring service which monitors the invocation of the methods which automatically triggers the processing of rules by a rule processing service when certain methods are invoked. We shall also describe how we apply the KBMS technology in the R&D efforts of a project called the National Industrial Information Infrastructure Protocols (NHIP) to provide a rule-based interoperabtity among heterogeneous systems. Permission to make digitel/hard copies of all or part of thk material for personal or claasroom use is granted witbout fee provided that the copies are not made or distributed for profit or commercial advantage, the copyright notice, the title of the pubhcation and its date appear, and notice is given that copyright is by permission of the ACM, Inc. To copy otherwise, to repubtieh, to post on aemera or to redistribute to Iiata, requirea specific permission andlor fee. CIKM ’95, Baltimore MD USA @ 1995 ACM 089791 -8124/95/11 ..

An association algebra for processing object-oriented databases

3.50 * Acknowledgement: This work is supported by the Advanced Research project Agency under ARPA Order #B76100. It is a part of the R&D effort of the NIIIP Consortium. The ideas and techniques presented here are those of-the authors and do not necessarily represent the opinion of other NIIIP Consortium members.

A Web-Based Knowledge Network for Supporting Emerging Internet Applications

An association algebra (A-algebra) is presented for manipulating object-oriented (O-O) databases which is analogous to the relational algebra for relational databases. In this algebra, objects and their associations in an O-O database are uniformly represented by association patterns and are manipulated by a number of operators. These operators are defined to operate on association patterns of both heterogeneous and homogeneous structures. Very complex structures (e.g. network structures of object associations across several classes) can be directly manipulated by these operators. Therefore, the association algebra has greater expressive powers than the relational algebra which manipulates on relations of compatible structures. Some mathematical properties of these operators are described together with their application in query decomposition and optimization. The algebra has been used as the basis for the design and implementation of an O-O query language called OQL and a knowledge rule specification language.<<ETX>>