International Journal of

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  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.

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There is abundant literature regarding virtual reality as a technology of interest in the present age. However, there are few comprehensive studies on strategies that can improve the level of urban design research using this technique. To investigate the issue, this paper first reviews the concept of virtual reality. Next, the opinions of experts in the field of virtual reality technology are summed up and key elements needed to create a virtual reality experience and key operators that establish the actual interaction of users with virtual environments are discussed. The use of Virtual Reality Modeling (VRM) in the urban design process and is also elaborated on. Uses of this technique in urban projects and advantages and limitations of its use in the field are discussed. Finally, the paper attempts to provide practical solutions and strategies to improve the quality of semi experiments developed virtual environment. This can improve the results and findings of research conducted with the technique. Strategies discussed in this article have been mostly derived from practical experience and research in recent years by the author. They can help provide a more robust analysis and reduce the errors made in the virtual environment.

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Transformation of land use-land cover change occurs due to the numbers and activities of people. Urban growth modeling has attracted authentic attention because it helps to comprehend the mechanisms of land use change and thus helps relevant policies made. This study applied logistic regression to model urban growth in the Ahvaz Metropolitan Area of Khuzestan province in IDRISI Selva software and to discover what are driving forces effective on the urban growth of Ahvaz city, and with what intensity? Historical land use and land cover data of Ahvaz were extracted from the 1991and 2006 Satellite images. The following two groups of factors were found to affect urban growth in different degrees as indicated by odd ratios: (1) Constraints Distance to the Bridge, Rural Areas, Planned town and Industry activities (all with odds ratios<1_or coefficient <0); and (2) Number of urban cells within a 5·5 cell window, Distance to the Hospitals, Main Road, High Road, Rail Line, River, CBD and Secondary centers, agriculture areas in distance more than 5km of Urban area and Vacant area (all with odds ratios>1_or coefficient >0). Relative operating characteristic (ROC) value of 0.906 indicates that the probability map is valid. It was concluded logistic regression modeling is suitable for Understanding and measuring of driving forces effect on urban growth. Second, unlike the Cellular Automata (CA) model, the logistic regression model is not temporally explicit; urban growth trend in Ahvaz isn't in the event of infill development strategy. Also, variables of sprawl based agents indicate more power than to compact base agents.

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Rapidly increasing urbanization in the world, especially in developing countries, let to increasing urban extents. Rapid urban growth causes to appearance many problems such as wasting environmental resources, inability of providing necessary services for citizens and unplanned growth. Urban mangers and planners need tools for understanding amount and size of future urban growths to prevent these problems. Urmia as capital city of west Azerbaijan province, in the last decades has considerable growth in both extent and population. This rapid growth caused to lose most high value agricultural resources in its surrounding. It has also caused many problems for urban management. Therefore, how city managers and urban planners can be aware of magnitude and location of Urmia city’s future growth and what is the best growth scenario for Urmia city? This paper uses a quantitative analysis research methodology to prediction and evaluation of growth scenarios for Urmia city. In this paper, SLEUTH model was applied to predict future urban growth of Urmia until 2050. Two different scenarios were employed include: Historical Growth Scenario (HGS) and Environment Protection Scenario (EPS). The result highlight that if the city continues its growth based on HGS scenario, in compare with growth based on EPS scenario, it would occupy more area. In this paper, we concluded that the EPS scenario can be more sufficient than HGS scenario. In addition, SLEUTH urban growth model can be used as a planning support model for urban planners and managers decisions for Urmia city based on scenarios.

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3D modeling and visualization in large-scale cities is a major difficulty for computer graphics. Studying photos of a big city reveals a variety of street patterns, buildings, shapes, and textures. This paper presents "procedural modeling" as a new approach to create three-dimensional modeling, especially for large-scale modeling. Procedural modeling deals with the production of semi-automatic (semi) content using a program or routine. This kind of modeling was historically utilized for 3D visualizing the natural properties, however, by releasing the CityEngine in 2008, the technology can easily be applied to urban environments as well. In this paper, this approach using a descriptive-analytical method will be examined, with particular emphasis on the extent to which procedural modeling is used in the design of cities, streets, buildings, etc., by CityEngine software. Therefore, while reviewing how architectural form grammars are used to generate 3D modeling procedures, two types of modeling including traditional and procedural modeling will be studied and compared and the benefits of procedural modeling will be revealed. After a description of the features of CityEngine, it will be introduced as a technique that follows procedural modeling. Finally, due to the advantages of procedural modeling, this type of modeling (algorithmic) is suggested as an alternative to manual modeling (traditional methods in urban design) to increase the accuracy, speed, and efficiency of the design and in addition, this will increase the flexibility of the design via this approach. In this regard, the workflow of the procedural modeling process will be provided using the CityEngine technique and a number of outputs of this technique that have been provided in the CGA will be presented.

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