An important issue in maintaining the industrial equipment is to introduce an appropriate maintenance policy to monitor the conditions of the equipment. In this research, an investigation on the concurrent effects of erosion and random shocks during the useful life of the equipment is studied. In this regard a model is introduced to optimize the total cost including logistic, complete repair and incomplete repair costs. The proposed model determines the optimal number of the incomplete repairs, the time duration between inspections and the probability of equipment to be failed. A numerical example is solved by means of computer simulation. The results indicate that the proposed model performs well for minimizing the costs of maintenance and repair.

Municipal solid waste management is one of the main challenges in mega cities. Consequences of landfilling and importance of using alternative energies contribute to the popularity of incineration facilities for city authorities. This article tries to determine the location and allocation decisions on landfills and incineration facilities regarding social and environmental effects. The proposed model minimizes revenue of selling recovered energy and minimizes visual pollution impacts. In addition, the environmental impacts of incineration and landfilling operations are considered as part of constraints. Using the data of Tehran's waste management organization, numerical results show the number of active transfer stations and traffic reduce leading to an increase on waste collection network's efficiency. The results also show a decrease on the landfilling and the amount of hazardous methane emissions as well as an improvement on power and heat energy recovery.

The purpose of this research is to study the role of the social media for knowledge sharing. The study presents a comprehensive review of the researches associated with the effect of knowledge management in social media. The study uses Scopus database as a primary search engine and covers 1858 of highly cited articles over the period 1994-2019. The records are statistically analyzed and categorized in terms of various criteria using an open source software package named R. The findings show that researches have grown exponentially during the recent years and the trend has continued at relatively stable rates. Based on the survey, knowledge management is the keyword which has carried the highest citations followed by social media and social networking. Among the most cited articles, papers published by researchers in United States have received the highest citations, followed by United Kingdom and China.

The purpose of this research is to investigate the status and the evolution of the scientific studies for the effect of social networks on big data and usage of big data for modeling the social net-works users’ behavior. This paper presents a comprehensive review of the studies associated with big data in social media. The study uses Scopus database as a primary search engine and covers 2000 of highly cited articles over the period 2012-2019. The records are statistically analyzed and categorized in terms of different criteria. The findings show that researches have grown exponentially since 2014 and the trend has continued at relatively stable rates. Based on the survey, decision support systems is the keyword which has carried the highest densities followed by heuristics methods. Among the most cited articles, papers published by researchers in United States have received the highest citations (7548), followed by United Kingdom (588) and China with 543 citations. Thematic analysis shows that the subject nearly maintained an important and well-developed research field and for better results we can merge our research with “big data analytics” and “twitter” that are important topics in this field but not developed well.

Selection of an appropriate contractor plays an important role for the success of the accomplish-ment of any construction project. This paper presents a multi-criteria decision making method for contractor selection. The proposed study uses six criteria, namely; Experience, Financial stability, Quality performance, Manpower resources, Equipment resources and Current workload for evaluating different contractors. Using analytical hierarchy process, the study ranks these criteria and finds the relative importance of them. Next, The technique for Order of Preference by Simi-larity to ideal Solution (TOPSIS) is used to rank the alternative contractors according to these criteria.

Nowadays, projects have become so widespread in the world that individuals and organizations are always involved in a variety of them. Recent advances in technology and fundamental chang-es in most scientific disciplines have had an essential impact on projects, and have made the na-ture and environmental conditions governing them to become more complex than before. With increasing complexity, the amount of information needed for project management increases. In general, the increasing complexity of projects is a growing source of project risks. It has been recognized that complexity affects the performance of a project and will be effective in its suc-cess. In this context, the traditional principles and practices of project management are no longer able to control the emerging complexity of projects. In addition, one of the key factors for the success of the projects is the appropriateness of the project manager's assignment. Many studies have been carried out in identifying the suitability criteria of the project manager and the methods of selecting the project manager. In most of these studies, the amount and type of complexity of the project are mentioned as factors influencing the design of an appropriate project manager. However, there has not yet been a specific approach for selecting the project manager with re-gard to the complexity of the project. Therefore, in this research, we try to investigate the rela-tionship between the complexity of the project and the merits of the project manager by applying a structural equation modeling approach.

During the past few months, the whole Canadian housing prices were witnessed an up-trend. People could enjoy the low interest rates to buy houses, even foreign investors were interested in participating in Canadian real estate pushing the prices up and up. As the COVID19 disappears, we see an uptrend on inflation and, on the other hand, the government placed some restrictions to prevent foreigners of purchasing houses in Canada. This paper investigates whether the government regulation and monetary policy could influence housing prices in Canada.

Enterprise resource planning (ERP) is the integrated management of core business processes, of-ten in real-time and mediated by software and technology. ERP gives us an integrated and updated image of core business processes based on common databases retained by a database man-agement system. ERP systems are able to track business resources including cash, raw materials, production capacity and the status of business commitments such as orders, purchase orders, and payroll. This paper presents different experiences of the implementation of ERP in Canada.