Modeling and simulation of processing plants are widely used in industry. Construction of a mathematical model for a plant is a time-consuming and error prone task. In light of extensive advancements in computer science (both hardware and software), computers are becoming a necessary instrument in industrial activities. Many software tools for modeling, simulation and optimization of processing plants have been developed. In this paper, a new tool, called "Modelsaz", for the modeling of physical-chemical-biological processing systems is introduced. This software can automatically generate mathematical models of various processing plants in Mathematica TM compatible format, based on conservation principle. Lumped systems are the basic elements of processing plants. The dynamic lumped models of the plants are based on transient mass and energy balances of these basic elements. "Modelsaz" has been developed under Microsoft-Windows 2000 operating system using Microsoft Visual C++6 programming environment. The software uses OBJECT-ORIENTED features and has a user-friendly graphical interface in order to facilitate the construction, modification and reusability of a processing system models.

One of the modern paradigms to develop software is OBJECT-ORIENTED analysis and design. In this paradigm, there are several OBJECTs in the software, and each OBJECT plays some specific roles. There is a sequence of activities to develop an analysis model. In the first step, this study works to develop an initial use case model. Then, in the second step, a number of concepts are identified, and a glossary of participating OBJECTs is built. Identifying attributes of OBJECTs (and classes) is one of the most important steps in the OBJECT-ORIENTED paradigm. This paper proposes a method to identify the attributes of OBJECTs and verify them. The method is also concerned with classifying and eliminating the incorrect attributes of OBJECTs. Then, the method is evaluated through a large application, a Control Command Police System. After that, several guidelines concerning attributes of OBJECTs based on the practical experience obtained from the evaluation are provided.

This article is the result of a practical work on applying the reverse engineering techniques to rebuild C++ programs architecture. A module in an OBJECT-ORIENTED program is composed of a set of related classes. To rebuil a program structure, the class dependency graph can be derived from the program text. To measure the relation between the classes. Coupling metrics may be applied. The result can be represented as a weighted directed graph. To reconstruct the program structure, the weighted graph should be clustered. Clustering is a NP-Complete problem. To resolve the problem, in this article a new genetic algorithm is presented. The key behind the success of this algorithm is its conformance with the genetic phenomenon in the nature.