This paper reports on recent work and directions in modern software ar-chitectures and their formal models with respect to software maintenance. The focus on maintenance attacks the most costly and frustrating aspect in dealing with large-scale software systems: keeping them up-to-date and responsive to user needs in changing environments. We employ mediators, autonomous modules which create in...

by the appropriate use of information technology, organizations can achieve sustainable competitive advantages. this technology because of including some characteristics such as being up-to-date, fast and precise and having different geographic localities all the time, has improved organizational efficiency, effectiveness and performance. in this article, we intend to investigate the role and e...

The world economic image has been changing. It has been a long time since the sole important resources of an organization were financial and physical. In the newly-emerged global economy, knowledge and information are accounted as the most significant resources in order to produce value. Obviously, as the demand for knowledge to reach success is increasing day by day, maintenance and enhancemen...

In this paper we motivate and describe materialized views, their applications, and the problems and techniques for their maintenance. We present a taxonomy of view maintenance problems based upon the class of views considered, upon the resources used to maintain the view, upon the types of modifications to the base data that are considered during maintenance, and whether the technique works for...

Maintenance costs of Information Systems (ISs) are high and growing. Systems of poor quality demand more maintenance resources than systems of good quality. The quality of software can be measured when it is maintained. By improving the quality of maintenance prone modules future maintenance costs may be lowered for those modules. In this article we will present a case study of porting a measur...

Effective highway maintenance depends on several activities, including the understanding of current and the prediction of future pavement conditions and deciding how to best allocate limited resources for maintenance operations. In this paper, a dynamic micro-level simulation model of highway deterioration and renewal processes is presented. This model is calibrated with data from eight road se...

For much of the 20th century, the accumulation of a considerable amount of information about the processes of aging did not reveal the underlying mechanisms. Toward the end of that century, the biological basis for aging became very much clearer. It became apparent that the best strategy for animals' survival was to develop to an adult, but not to invest resources in maintaining the body, or so...

An important part of the lifecycle costs for pump stations are the support costs associated with energy and preventive maintenance of the pumps. Both cost terms are interrelated because a trade-off exists between maintaining pumps frequently (with increased pump efficiency, reduced energy costs and increasing maintenance costs, and pump unavailability) and extending the intervals between the ov...

water resources are of vital human resources and of the three main elements of ecosystem. almost half of the agricultural products of the world are being produced in irrigation schemes. in today's world, the population is considerably increasing and consequently severe shortage of food threatens about two-third of the world's population. moreover, water resources are facing more serious crisis ...