INTERNATIONAL JOURNAL OF INDUSTRIAL ENGINEERING AND PRODUCTION MANAGEMENT (IJIE) (INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE) (PERSIAN)
Year:2006 | Volume:17 | Issue:2|Papers Count:10

In this paper, we are going to study the unstructured decisions, their interactions in strategic and tactical level and application of "integrated definition technique (IDEFO)"as a tool for analysis. The IDEF technique is used as a structured approach to analyze "Decision Network Problem" by decreasing the degree of freedom in this sort of decisions. By decision network we mean "a set of interrelated decisions". There are lots of studies in the context of decision making but not so much related to interaction aspects of decisions. This paper, mainly, is dealing with the mentioned shortcoming of the decision making theories.Finally, with a case study as conclusion, the implementation of our achievements will be mentioned.  

A modified model for optimum allocation of inspection in a serial production line is presented and solved by the Genetic Algorithms. In this model, at each stage, inspection is limited only to those characteristics that are produced or modified after the last inspection. The modification assumes that all parts that pass the inspection enter the next production stage as conforming. In addition non-conforming parts, according to their defects, may be scrapped or be sent to earlier stages of production line for rework or to a side line for repair. Genetic algorithm is a good replacement for dynamic programming or bound and branch method when dealing with the nonlinearities introduced into the problem.

The present era is named as knowledge era and many countries know that they should select correct and suitable science and technology policies. The rate of development especially in the north countries shows that the organizations are moving towards knowledge based organizations. Management of intellectual capital in every country or, in a better way to say, knowledge management at macro level, needs to select suitable strategies and correct science and technology policies in order to smooth the way towards knowledge based development.This paper is to answer a main question about the reasons of success for science and technology policies in some developed countries. A qualitative case study technique has been used for data collection to gain insights into the topic being investigated. For that grounded theory research approach has been selected by which the collected data are categorized and analyzed through specific stages.A semantic network has been developed by categorized data and finally a theory was built. This theory shows the reasons for success in science and technology policies in a clear way.

Condition monitoring of old railway bridges is a very essential and important subject.Dynamic testing is carried out to determine characteristics of the bridge. Although, dynamic testing with shaker or drop weight is expensive, but dynamic testing with ambient vibration is very economical. The method of analyzing the ambient signals is still under study. In this study, the ambient vibration testing of Akbar Abad railway bridge was carried out. The acceleration signals of the bridge were processed by stochastic subspace identification method. The state space model of the bridge was identified and the modal characteristics of the system were calculated.

Many orthogonal methods have been used for nonlinear analysis of structures. Some of the most significant orthogonal methods are: normal plane, updated normal plane, and unbalance force orthogonal. It should be mentioned that most of them have inadequacies in analyzing some structures. In this paper, several new orthogonal methods have been offered. The aforementioned techniques are on the basis of previous methods parameter improvement and increase of converging rate. Ability of these techniques will be shown, by analyzing some sample structures.

Imprecise construction work might cause imperfection in the shell of R.C.hyperbolic cooling towers. The cooling towers with large imperfection could collapse due to wind load. The aim of this research is to study the cracks spreading in the shell of a typical R.C. cooling tower with and without imperfection. In Finite Element analysis reinforces bars with nonlinear behavior and solid elements were used. The solid elements which were used in this analysis could crack in three directions. The study on the sample cooling towers showed that deformations and crack spreading differ in the cooling tower shell with and without imperfection due to weight and thermal loads. At the end of the weight and thermal loads, vertical cracks were seen all over the outer side of the perfect shell and intermittent horizontal cracks happened in the shell of cooling tower where it had its minimum thickness. On the other hand, in an imperfect shell, intermittent vertical and horizontal cracks were seen on the outside of the cooling tower shell due to the weight and thermal loads. When wind loads was added to the weight and thermal loads, the cracks spreading was seen to be similar for both perfect and imperfect R.C. Shell.

In this research, a model is developed for the optimal design of storm water networks.The model uses the powerful genetic algorithm as the search engine. The "Transport" module of "SWMM 4.4h" is used as the hydraulic analyzer of the model. Two different approach are used to formulate the problem with varying degrees of success in reaching a "near optimal" solution. The proposed model is applied to some benchmark examples in the literature leading to achieve good solution compared to previous results.

A numerical model was developed to simulate the 3-D solidification of A319 aluminum alloy in a sand mold. The energy equation governing the process was derived based on total enthalpy conservation within the system. A source-based method was used to consider the release of latent heat during solidification. The governing energy equation was dicretized for a three-dimensional domain using a control volume based finite difference. The discretized equations associated with proper boundary conditions were solved numerically using TDMA (Tri Diagonal Matrix) algorithm. The model developed in this work, was verified by experimental results obtained from thermal analysis tests carried out on the casting. In order to evaluate the effect of latent heat release mode within the mushy region on temperature field and solidification profile in the casting, four modes were tested. These are linearly released mode, parabolic mode, and latent heat release modes based on lever rule and Scheil equation. A comparison of the computed results with the experiments showed that by incorporating the latter mode of latent heat release in the model, the solidification behavior of the casting can be predicted more accurately.