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Mohsen Faizi, Farhang Mozaffar , Mehdi Khakzand,
Volume 18, Issue 6 (7-2007)
Abstract

  In this paper, authors tackle three very important questions that need to be answered if a theory of design is to be constructed. The first is what designers do, Which we attempt to illustrate with the help of case studies and theories of design practice. The second question is what guides designers. Here, authors try to present some of the proposed normative positions about design, to show the similarities and differences between positions and a framework of how they can be categorized. The main (third) question is how the design thinking process can be represented drawing upon on a review of recent studies of design practice and designer's creativity.

  One approach to design thinking is to extract the features of the designers' strategic knowledge, for which comparative studies between expert designers and novices are useful. Also, controlled experimental studies may be adopted in order to understand the nature of the idea generation process.

Finally, the methods of research and representation of design thinking in order to gain a deeper understanding of the designers' creativity are proposed .
Fatemeh Mehdizadeh Saradj,
Volume 18, Issue 6 (7-2007)
Abstract

When a specific building is examined and analysed for its architectural merits, it is the visible, superficial aspects, which are considered, for example: aesthetics, function, spatial relationships, and landscape. One of the most important invisible factors that should be considered in the design process is the safety of buildings against natural hazards, particularly against earthquakes. While the provision of earthquake resistance is accomplished through structural means, the architectural designs and decisions play a major role in determining the seismic performance of a building. In other words, the seismic design is a shared architectural and engineering responsibility, which stems from the physical relationship between architectural forms and structural systems. It is economic to incorporate earthquake resistance in the stage of design than to add it later in the structural calculation or strengthening after completion. In addition, a building with proper earthquake-proof design will be more effective against earthquakes than the one with complementary strengthening. This paper will demonstrate that evidence for this lies in many historical buildings, which have withstood earthquakes throughout the hundreds of years without having been reinforced with special material. The fact is that the master builder or Mimar (traditional architect) of historic buildings was simultaneously designing the architecture as well as choosing the suitable form, proportion, and material for the best structural performance.
Asghar Mohammad Moradi , Mahdi Akhtarkavan,
Volume 18, Issue 6 (7-2007)
Abstract

The present paper will investigate the specific elements of architectural design based on Islamic beliefs, by taking Iranian Architectural values and vernacular climate design methods into consideration. This research will assess the spirit of experimental elements, created by the inhabitants, according to recent scientific findings. The main concentration will be on the physical design of rural areas in hot, arid and sunny regions of Iran in order to have active and healthy environments and to emphasize on transferring all these sustainable values to the future.
Esmaeil Shieh, Ayyoob Sharifi,
Volume 18, Issue 6 (7-2007)
Abstract

  The study seeks to address the importance of urban stream ecosystems from the perspective of urban ecology, human health and social well-being in the context of urban planning. The case study area is Paveh stream in the City of Paveh. The data from the case study area were gathered from questionnaire, existing scientific and library studies and by conducting interviews with residents and authorities. Once the importance of the biodiversity of the stream had been studied based on the existing ecological data, the social importance of the stream and the linkages between human health, social well-being and the biodiversity of the stream ecosystem were addressed.

  Based on the results of the survey and other sources of information, it was discussed that urban stream ecosystems can be rich in biodiversity and function as ecological movement corridors for species .Urban stream corridors can thus be an important part of the urban green infrastructure .Also we can make the weather fine, extend green space, prepare peaceful environment for residents and bring the countryside effects of nature into cities through improvement of stream landscape.

Finally, regarding the finding of this study some suggestions and implications are mentioned to improve the quality of the stream.
Ali Yaran,
Volume 18, Issue 6 (7-2007)
Abstract

This paper will promote many questions about the design validity of these exciting blocks. The physical design of these blocks is prone to have social and economical problems, and it is part of the visual pollution and disturbance created on the sky line of Scottish cities special Glasgow. This paper focuses on the necessity to establish a source of initial design for high rise housing design problem classes theory. A thorough research of all the estates in Glasgow area was launched. Thus, a high amount of information was classified, in an attempt to establish a theoretical approach to support the evaluation and appraisal of current blocks problems. The new class's theory in high rise housing design problems is used as a vehicle for conducting this paper analysis. Classification includes physical and social design problems domains. The physical problems domain variables of the numbers of stories, dwellings, entrances, type of corridor, access from the streets and sharing of the site. Furthermore, to the social problems domain variables of graffiti, damage, litter, crime, drugs, child density and health have been examined. Moreover, their interdependent relationships were explored throughout the new classes' theory. The study of the new classes, theory may prove to be extremely vital for future direction in adapting some from of urban design problem solving techniques. It also serves as an evaluation tool for housing design appraisal in the city from Glasgow and similar cities worldwide.
Mehdi Alaeiyan,
Volume 19, Issue 1 (3-2008)
Abstract

We call a Clayey graph Γ = Cay(G, S) normal for G, if the right regular representation R(G) of G is normal in the full automorphism group of Aunt(Γ). in this paper, we give a classification of all non-normal Clayey graphs of finite abelian group with valency 6. 
Hamid Tavallaee , Rezvan Hamid A. Tavallaee and Rezvan. Varmazyar,
Volume 19, Issue 1 (3-2008)
Abstract

Let

 be a commutative ring and  be a unitary  module. We define a semi prime sub module of a module and consider various properties of it. Also we define semi-radical of a sub module of a module and give a number of its properties. We define modules which satisfy the semi-radical formula and present the existence of such a module.

Rahman Farnoosh, Behnam Zarpak,
Volume 19, Issue 1 (3-2008)
Abstract

  Stochastic models such as mixture models, graphical models, Markov random fields and hidden Markov models have key role in probabilistic data analysis. In this paper, we have learned Gaussian mixture model to the pixels of an image. The parameters of the model have estimated by EM-algorithm.

  In addition pixel labeling corresponded to each pixel of true image is made by Bayes rule. In fact, we introduce a new numerically method of finding maximum a posterior estimation by using EM-algorithm and Gaussians mixture distribution. In this algorithm, we have made a sequence of priors, posteriors and they converge to a posterior probability that is called the reference posterior probability. Maximum a posterior estimated can determine by the reference posterior probability that will make labeled image. This labeled image shows our segmented image with reduced noises. We show this method in several experiments.


.a. Seifoddin, M. H. Salimi , M. M. Syed Esfahani,
Volume 19, Issue 1 (3-2008)
Abstract

Innovations, commercialized by new or old established firms, located at the core of industrial renewal process. The innovation concept has suffered transformations, along with the evolution of the models that try to explain and understand the innovation process. The innovative process corresponds to all activities that generate technological changes and the dynamic interaction between them, not necessarily being novelties. Linier model, Chain-Linked Model and National Innovation Systems (NIS) Approach, are three models that have developed for innovation process. Innovation process can be viewed as evolutionary process. One can recognize some mechanism for innovation evolution. These are grouped into two classes those that increase configurations variation and those that decrease it. Emergence of knowledge, knowledge flow and recombination are the mechanism to increase variation of configuration. Internal and external selections are the mechanism to selecting. Innovation operators are evolutionary operators that create new combinations of configuration and increase variation. This paper develops an evolutionary cycle in innovation process and extends evolutionary mechanisms of innovation.


M.b. Aryanezhad , E. M.b.aryanezhad & E.roghanian ,
Volume 19, Issue 1 (3-2008)
Abstract

  Bi-level programming, a tool for modeling decentralized decisions, consists of the objective(s) of the leader at its first level and that is of the follower at the second level. Three level programming results when second level is itself a bi-level programming. By extending this idea it is possible to define multi-level programs with any number of levels. Supply chain planning problems are concerned with synchronizing and optimizing multiple activities involved in the enterprise, from the start of the process, such as procurement of the raw materials, through a series of process operations, to the end, such as distribution of the final product to customers.

  Enterprise-wide supply chain planning problems naturally exhibit a multi-level decision network structure, where for example, one level may correspond to a local plant control/scheduling/planning problem and another level to a corresponding plant-wide planning/network problem. Such a multi-level decision network structure can be mathematically represented by using “multi-level programming” principles. This paper studies a “bi-level linear multi-objective decision making” model in with “interval” parameters and presents a solution method for solving it this method uses the concepts of tolerance membership function and multi-objective multi-level optimization when all parameters are imprecise and interval .

 


S. Rastegari, Z. Salehpour , Bakhshi , H. Arabi,
Volume 19, Issue 5 (7-2008)
Abstract

Formation mechanism of silicon modified aluminide coating applied on a nickel base super alloy IN-738 LC by pack cementation process was the subject of investigation in this research. Study of the microstructure and compositions of the coating was carried out, using optical and scanning electron microscopes, EDS and X-ray diffraction (XRD) techniques. The results showed that due to low partial pressure of silicon halide in Pack process, the amount of soluble silicon in the coating can not exceed 1 wt % of the total coating composition, although the Si content of the particles present within the outer coating sub-layer could reach as far as 5 wt%. Thus, the small amount of soluble Si within the coating could not provide the necessary conditions for formation of any intermetallic and it seems that the formation and growth behavior of various sub-layers in Si-modified aluminide coating is similar to that of simple aluminide coating. Three sub-layers were detected in the coating structure after being subjected to diffusion heat treatment. They were an outer Ni-rich NiAl sub-layer a middle Ni-rich NiAl and an inter diffusion sub-layers. The details of formations and growth mechanism of these sub-layers has been discussed in this research.


H. Arabi, M.t Salehi, B. Mirzakhani, M.r. Aboutalebi , S.h. Seyedein , S. Khoddam,
Volume 19, Issue 5 (7-2008)
Abstract

Hot torsion test (HTT) has extensively been used to analysis and physically model flow behavior and microstructure evolution of materials and alloys during hot deformation processes. In this test, the specimen geometry has a great influence in obtaining reliable test results. In this paper, the interaction of thermal-mechanical conditions and geometry of the HTT specimen was studied. The commercial finite element package ANSYS was utilized for prediction of temperature distribution during reheating treatment and a thermo-rigid viscoplastic FE code, THORAX.FOR, was used to predict thermo-mechanical parameters during the test for API-X70 micro alloyed steel. Simulation results show that no proper geometry and dimension selection result in non uniform temperature within specimen and predicted to have effects on the consequence assessment of material behavior during hot deformation. Recommendations on finding proper specimen geometry for reducing temperature gradient along the gauge part of specimen will be given to create homogeneous temperature as much as possible in order to avoid uncertainty in consequent results of HTT.


N. Parvini Ahmadi, T. Czerwiec ,
Volume 19, Issue 5 (7-2008)
Abstract

Low temperature plasma assisted nit riding treatments of 316 stainless steel produce a complex layer constituted by tow different metastable f.c.c. solid solution denoted ( γ N1 and γ N2 ). About the formation of these double layers, different hypothesis was proposed in the literature. For verifying these hypotheses, the effects of differentes conditions such as nit riding temperature, cleaning and nit riding duration and cooling state have been studied. The results show that γ N2 sub layer produce during the ion bombardment cleaning procedure, before the nit riding treatment. Also the formation of the γ N2 layer is not connected to the cooling state of the sample after nit riding treatment.


Mohammad Ali Rezvani ,
Volume 19, Issue 5 (7-2008)
Abstract

It is the purpose of this paper to introduce a computer software that is developed for the analysis of general multi degree of freedom rotor bearing systems with non-linear support elements. A numerical-analytical method for the prediction of steady state periodic response of large order nonlinear rotor dynamic systems is addressed which is based on the harmonic balance technique. By utilizing harmonic balance with appropriate condensation, it is possible to considerably reduce the number of simultaneous nonlinear equations inherent to this approach. Using this method, the set of nonlinear differential equations governing the motion of the rotor systems is transformed to a set of nonlinear algebraic equations. A condensation technique is also used to reduce the nonlinear algebraic equations to those only related to the physical coordinates associated with nonlinear components. The stability (linear) of the equilibrium solutions may be conveniently evaluated using Floquet theory, particularly if the damper force components are evaluated in fixed, rather than rotating, reference frames. The versatility of this technique is illustrated on systems of increasing complexity with and without damper centralizing springs.


N. M. Nouri, A. Eslamdoost , M. Shienejad,
Volume 19, Issue 5 (7-2008)
Abstract

 In the present paper, partial cavitation over various head-forms was studied numerically to predict the shape of the cavity. Navier-Stokes equations in addition to an advection equation for vapor volume fraction were solved. Mass transfer between the phases was modeled by a sink term in vapor equation in the numerical analysis for different geometries in wide range of cavitation numbers. The re-entrant jet formation, which is the main cause for the cavitation cloud separation, was modeled very well with a modification of turbulent viscosity. In regions with higher vapor volume fractions (lower mixture densities) a modification of the turbulence model was made by artificially reducing the turbulent viscosity of mixture. Computed shapes of cavities were found to be in good agreement with those of the reported experiments. Simulation results also compared well with those obtained from analytical relations.
M. Sedighi , M. Noorani Azad,
Volume 19, Issue 5 (7-2008)
Abstract

Along with increasingly development of CAD/CAM software and their application in various industries, minimizing of the machining time is found to be more important. In this paper, firstly the concerning subjects are discussed regarding classification of the optimization techniques. These are programming techniques, high speed machining techniques and feed rate optimization techniques. As a case study, an NC code was generated for machining of a plastic die by means of a dedicated software and the die was machined conventionally. Then the workpiece was machined using optimization techniques. Finally times taken for two approaches have been compared. The result shows machining time after optimization has been reduced considerably (64%).

 

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