Vlad Ingar Wietrzyk

ADDROL: a method for on-line reorganization in a multisystem DBMS with shared disks

This paper describes the design of a method, called ADDROL-Algorithm for Distributed Database Reorganization On-Line, which supports on-line reorganization of the distributed database. The contributions of the paper are both theoretical and experimental. We present an algorithm for maintaining the biconnected components of a graph during a sequence of edge insertions and deletions.

Web based electronic marketplaces: trading through collaboration

This paper introduces the issues being addressed by electronic markets in the form of infrastructure, architecture and core functions. Supply chain management and the collaborative product development are also included here. Software providers and marketplace operators often summarise the two under the term e-collaboration. The core goal of the current analysis is to establish the significance and importance of the electronic marketplaces in the Internet driven economy. In this paper, we analyze the factors that impact on the efficiency in the supply chain, including e-business portal operational and technological environment.

A Strategy for MLS Workflow

This paper describes the design of a model as well as an architecture to provide support for distributed advanced workflow transactions. We discuss the application of transaction concepts to activities that involve integrated execution of multiple tasks over different processes. This kind of applications are described as transactional workflows. The classical commit protocol, used in many commercial systems, is not suitable for use in multilevel secure distributed workflow database systems that use a locking protocol for concurrency control. We choose to develop formal framework for secure distributed workflow architecture since we are actively involved in building a prototype of such a system. We strive to develop a practical logical characterization of multilevel secure (MLS) distributed workflow for the first time using the inherently difficult concept of non-monotonic reasoning.

On the Analysis of On-Line Database Reorganization

We consider the problem of on-line database reorganization. The types of reorganization that we discuss are restoration of clustering, purging of old data, creation of a backup copy, compaction, and construction of indexes. The contributions of this paper are both of theoretical and of experimental nature.

Designing responsive database-driven Web sites

With the wide availability of content delivery networks, many e-commerce Web applications utilize edge cache servers to cache and deliver dynamic content at locations much closer to users, avoiding network latency. Replication of Web documents can improve both performance and reliability of the Web service. Response time is a key differentiation point among electronic commerce (e-commerce) applications. We choose to develop a framework for a secure, highly available distributed workflow architecture since interworkflow is anticipated as a major supporting mechanism for business-to-business electronic commerce. In this paper, we analyze the factors that impact the performance and scalability of a database-driven Web site.

Flexibility if group communication service

A group protocol supports applications with enough quality of service (QoS) in change of QoS supported by the network. An automatic group service is supported for applications by cooperation of multiple autonomous agents. Each agent autonomously takes a class of each protocol function like retransmission. Classes taken by an agent are required to be consistent with, but might be different from the others. A group is composed of views in each of which agents autonomously take protocol classes consistent with them.

An Architecture for Work Flows Interoperability Supporting Electronic Commerce

Distributed object architectures (DCOM, CORBA, Java RMI) coupled with Internet and Intranet technology have a great impact on process-centered environments and distributed workflow management. Management of the workflow operations of each organisation in the interworkflow must be done in a distributed environment. An electronic commerce (EC) process is a business process and defining it as a workflow provides all the advantages that come with this technology. This paper describes the design of a model as well as an architecture to provide support for distributed advanced workflow transactions. The componentwise architecture of the system makes it possible to incorporate the functionality and thus the complexity only when it is actually needed. We discuss the application of transaction concepts to activities that involve integrated execution of multiple tasks over different processes. This kind of application is described as transactional workflows.