Towards making object horizontal fragmentation dynamic.

Distributed object database design enhances application performance by reducing data communication cost incurred while accessing nonlocal data. The distributed object database design problem is accomplished through fragmentation of database classes and allocation of these fragments to distributed sites. Fragmentation reduces the amount of irrelevant data accessed by applications locally as well as the amount of data transferred to remote sites when migration is required. Existing object fragmentation algorithms use inputs from static requirements analysis. Major changes in a domain would entail a re-analysis of the system and re-running of the distributed design algorithms. In order to make these system changes more acceptable by user, fragmenting database objects dynamically is desired. This thesis aims at defining techniques for initiating dynamic horizontal fragmentation of objects in an object oriented database system. It first presents an architecture that triggers dynamic object horizontal fragmentation and is capable of measuring the performance of existing object horizontal fragmentation schemes. Then it proposes a set of algorithms for (1) measuring the performance of object horizontal fragmentation schemes, (2) determining system performance threshold and (3) monitoring changes in system inputs. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1999 .Z55. Source: Masters Abstracts International, Volume: 39-02, page: 0535. Adviser: C. I. Ezeife. Thesis (M.Sc.)--University of Windsor (Canada), 1999

Model Based Development of Quality-Aware Software Services

Modelling languages and development frameworks give support for functional and structural description of software architectures. But quality-aware applications require languages which allow expressing QoS as a first-class concept during architecture design and service composition, and to extend existing tools and infrastructures adding support for modelling, evaluating, managing and monitoring QoS aspects. In addition to its functional behaviour and internal structure, the developer of each service must consider the fulfilment of its quality requirements. If the service is flexible, the output quality depends both on input quality and available resources (e.g., amounts of CPU execution time and memory). From the software engineering point of view, modelling of quality-aware requirements and architectures require modelling support for the description of quality concepts, support for the analysis of quality properties (e.g. model checking and consistencies of quality constraints, assembly of quality), tool support for the transition from quality requirements to quality-aware architectures, and from quality-aware architecture to service run-time infrastructures. Quality management in run-time service infrastructures must give support for handling quality concepts dynamically. QoS-aware modeling frameworks and QoS-aware runtime management infrastructures require a common evolution to get their integration

The pros and cons of using SDL for creation of distributed services

In a competitive market for the creation of complex distributed services, time to market, development cost, maintenance and flexibility are key issues. Optimizing the development process is very much a matter of optimizing the technologies used during service creation. This paper reports on the experience gained in the Service Creation projects SCREEN and TOSCA on use of the language SDL for efficient service creation

A survey of agent-oriented methodologies

This article introduces the current agent-oriented methodologies. It discusses what approaches have been followed (mainly extending existing object oriented and knowledge engineering methodologies), the suitability of these approaches for agent modelling, and some conclusions drawn from the survey