غلامرضا هروی

Long-term delays to complete residential units, due to lack of adequate and punctual financing, is considered as a developer's problem, in the process of housing production. In this regard, the present study, with the consideration of the challenges that obstacle the efficient pre-sale of residential units, aims to determine the pre-sale policies of housing by providing a model based on the system dynamics approach in order to provide sufficient and punctual financial resources, reduce delays in completion, reduce opportunity cost and to achieve a balance between developers’ and buyers’ profit. After making a dynamic model and validating it, 48 scenarios consisting of the states of five lever variables were simulated and after analyzing the results, improvement policies which include four alternatives were extracted. The results indicate that to produce the residential units with average prices, whether the percentage offered of area for initial pre-sale is 0/3, the initial pre-sale discount coefficient relative to the price of the completed unit is 0/06 and the down payment coefficient is 0/3, from which the mentioned variables will lead to a significant reduction in completion delays and opportunity cost, and also will balance the profit of both developers and buyers.

The construction industry accounts for a large share of the industry in various countries. The rate of accidents and deaths in this industry is much higher than in other industries. Safety is a major concern in the construction industry. One of the most dangerous parts of the industry is the construction of high-rise buildings. In this research, an attempt has been made to evaluate the level of factors affecting the safety of the project, to be able to predict the level of safety of future projects based on the records and information of previous projects. Because with a correct understanding of the impact of factors on safety, it is possible to take the necessary policies to improve safety and reduce damage to this part of the industry and prevent the waste of resources. To achieve this purpose, first, the factors affecting safety have been identified by reviewing the literature and reviewing the unofficial statistics of work-related accidents, and then the relationship between these factors and the level of project safety for 95 projects in Tehran and Kish Island is developed. It was conducted with the help of a questionnaire, with the help of a Bayesian network and multiple linear regression. In the proposed model, the effect of each of the groups affecting the safety of the project is determined. “Monitoring and supervising the safety" and "safe process of doing work" are among the most influential factors on the safety level of high-rise building projects; regression coefficients were 0.338 and 0.264, respectively.

Considering the worldwide increasing rate of energy consumption and its environmental degradation effects, and considering the use of none-renewable energy sources such as the fossil fuels, consideration of energy management issues has become more important. Given the 40% share of the building industry's total energy consumption, as well as the 80% share of energy consumed during the operation period, of the total energy consumption during the life cycle of the building, attention to the areas of energy management and optimization during the operation period of the buildings can have a major impact on energy efficiency. In this research, through identifying building energy management tools and studying previous studies and assessing the effects of building energy management systems, the economic and environmental impacts of using building energy management systems on the annual energy consumption in an office building in Tehran as a case study has been investigated. The results indicate a 32 percent reduction in the energy consumption and a significant reduction in the release of the environmental pollutants in smart mode compared to the baseline. Moreover, considering the social costs associated with the emitted pollutants as well as the return period, it has been attempted to identify the factors contributing to the economic justification of using smart heating and cooling systems. According to the results, the use of smart energy management systems can be considered as an effective step in optimizing and managing energy consumption in the construction sector.

Considering the population growth and rapidly housing demands, it is inevitable to adopt industrial building systems for the purpose of raising the quality of industrialized building construction. Construction industrialization is an important factor in increasing production and striking the right balance between supply and demand in the market. There are multiple methods for industrialized building construction, the most common of which is the prefabrication concrete industry. An attempt has been made in this study to put forward the appropriate method for understanding the current status of this industry in developing countries and adapting it with economic, social and environmental criteria of sustainable development and to present suitable management methods for choosing and piloting the route toward sustainable development. The results suggested that when compared to the cast in place concrete, prefabricated concrete is of higher quality according to the sustainable development criteria. The results indicated that the order of desirability of prefabricated concrete in terms of different aspects of sustainable development is as follows: environmentally, socially and economically. According to the sustainable development criteria, prefabricated concrete could provide more opportunities to communication development. Moreover, there are more opportunities than threats in the industry of prefabricated construction. In this article, appropriate strategies were formulated by means of SWOT analysis for the purpose of developing and improving and expanding the prefabricated concrete industry