Sharif Digital Repository

Heaters are one of the central parts of natural gas reduction stations using turboexpanders to prevent the formation of hydrate and corrosion failure. This study intends to design a fired heater by applying a combustion sub-model to derive an optimal model for this kind of application. This model is developed to accurately consider all subsections of the fired heater namely radiation, convection, and shield sections, as well as flue gas composition, and its volume. Within this context, a multi-objective optimization is employed to identify the optimal design of the gas-fired heater in the natural gas reduction station for the Ramin power plant case study. The total economic and environmental... 

This paper aims to propose a framework by which decision-makers can evaluate and compare alternatives for sustainable island-based tourism development. The uncertainties and risks involved in information and judgment within the evaluation process were taken into account by using a hybrid approach, which combined the Delphi method, fuzzy set theory, and a discrete multi-criteria method based on prospect theory called TODIM (an acronym in Portuguese of interactive and multiple-criteria decision making). The decision making model examined 3 different techniques for aggregating the viewpoints of different decision-makers and explored how the aggregation technique would affect the ranking of the... 

The present article aims to investigate the cause-and-effect relationship between the employees’ psychological empowerment (PE) and dimensions of knowledge management (KM) in an oil company, using the fuzzy decision-making trial and evaluation laboratory method. The study population consists of oil company experts. The sample size is determined based on the theoretical saturation limit. The present findings show that PE is the strongest causative factor with significant effects on knowledge creation (KC) and knowledge dissemination (KD). Among the KM dimensions, the most influential factors are the dimensions of KC, knowledge application, and knowledge capture (KCA). Of all KM dimensions,... 

Data Envelopment Analysis (DEA) is a method to measure the efficiency of a DMU (Decision Making Unit, e.g. school, public agencies and banks). One of the ways for determining rank of DMUs is efficient score of each DMU. An interesting research issues is to discriminate between efficient DMUs. In literatures, supper efficiency is an applicable method for ranking efficient DMUs. The main drawback of this method is an inability of this method to rank non-extreme efficient DMUs. Therefore, this issue reduces the usefulness of this method. In this paper we propose a new ranking system for non-extreme efficient DMUs (Decision Making Units) based upon the omission of DMUs from reference set of the... 

Financial performance evaluation is a very crucial process for industries in current highly competitive environment. Therefore, designing an accurate and appropriate performance evaluation framework is beneficial for insiders and also shareholders of a company. To evaluate financial performance, we need to consider some financial indicators that reflect the competitiveness of a company. There are many financial indicators and criteria that are vague and can be regarded as a fuzzy multiple criteria decision-making (MCDM) problem. In this paper, we developed a new financial performance evaluation framework to rank the companies in Iranian petrochemical industry based on fuzzy MCDM approach. To... 

Information technology (IT) outsourcing has been recognized as a new methodology in many organizations. Yet making an appropriate decision with regard to selection and use of these methodologies may impose uncertainties and risks. Estimating the occurrence probability of risks and their impacts organizations goals may reduce their threats. In this study, an extended analytical hierarchical process method is tailored based on interval-valued hesitant fuzzy information to assess the risks in IT outsourcing. In the proposed approach, the weight of each decision maker is implemented in process of the proposed method by considering the concept of simple additive weighting method to decrease the... 

A novel approach in Terrain Following/Terrain Avoidance (TF/TA) flight is proposed that facilitates flying over unknown terrains. Intelligency is implemented using fuzzy decision making tools. This method can be used in offline design in trajectory planning which has wide applications in TF/TA. A relationship b etween slope of terrain and aircraft height with speed of aircraft is constructed by fuzzy approach  

The growing importance of energy consumption has become an integral part of many decision-making processes in various organizations. In this paper, a framework is proposed for an organization where the undertaken project is implemented by multi-skilled workforce and energy tariffs depending on the time-of-use. This is a real-life situation where energy tariffs are significantly high during the peak demand compared to the one in off peak demand in order to control overloaded consumption of energy. A formulation is developed for the problem to minimize the total cost of consuming required energy. The proposed formulation is validated using several small-scale instances solved by GAMS software.... 

In this paper we propose a modified Fuzzy Technique for Order Performance by Similarity to Ideal Solution (modified Fuzzy TOPSIS) for the Multi-criteria Decision Making (MCDM) problem when there is a group of decision makers. Regarding the value of the truth that a fuzzy number is greater than or equal to another fuzzy number, a new distance measure is proposed in this paper. This distance measure calculates the distance of each fuzzy number from both Fuzzy Positive Ideal Solution (FPIS) and Fuzzy negative Ideal Solution (FNIS). Then, the alternative which is simultaneously closer to FPIS and farther from FNIS will be selected as the best choice. To clarify our proposed procedure, a... 

Risk aversion is a prevalent phenomenon when sufficiently large amounts are at risk. In this paper, we introduce a new prescriptive approach for coping with risk in sequential decision problems with discrete scenario space. We use Conditional Value-at-Risk (CVaR) risk measure as optimization criterion and prove that there is an explicit linear representation of the proposed model for the problem  

Evaluation of a project and its contractors has considerable importance in gas well-drilling projects due to their high investments and worth. In this paper, the quality of some gas well-drilling projects is analyzed in order to evaluate and grade project tasks. A neuro-fuzzy network is utilized to learn the grading process and generate models. To select among these models, a ranking method, namely technique for order of preference by similarity to ideal solution (TOPSIS) is employed. During seven gas well-drilling projects, 77 tasks are studied based on quality practitioners[U+05F3] points of view. After generating the primary models, three indices namely, root mean square error (RMSE),... 

Automatic image annotation has emerged as an important research topic due to the existence of the semantic gap and in addition to its potential application on image retrieval and management. In this paper we present an approach which combines regional contexts and visual topics to automatic image annotation. Regional contexts model the relationship between the regions, whereas visual topics provide the global distribution of topics over an image. Conventional image annotation methods neglected the relationship between the regions in an image, while these regions are exactly explanation of the image semantics, therefore considering the relationship between them are helpful to annotate the... 

Organizational performance evaluation is a very vital and sensitive process in any industry. One of the most crucial aspects of performance assessment is consideration of financial performance evaluation. In this kind of evaluation, we face many criteria and index to performing and also designing a comprehensive and effective model. Thus, this situation can be regarded as a fuzzy multiple criteria decision-making (MCDM) problem, so the fuzziness and uncertainty of subjective perception should be considered. In this paper performance evaluation of seven active companies in the petrochemical industries was evaluated using combined method of fuzzy and analytic hierarchy process. In this paper... 

Finding the most suitable location among some alternatives is one of the most important factors which could affect the whole success of the construction of a facility. The facility site selection is a multiple criteria decision making (MCDM) problem including both quantitative and qualitative criteria. Due to some difficulties in many real life cases, defining the exact values for MCDM problems is almost impractical and, it's preferable to use fuzzy values (fuzzy numbers) in this type of problems. In this study, we try to determine a suitable location for a Sewage Treatment Plant by using a new fuzzy weighted average (FWA) method. For this aim, ten different criteria is defined and then, by... 

The American Association of State Highway and Transportation Officials (AASHTO) and Federal Highway Administration (FHWA) encourage the use of various Accelerated Bridge Construction (ABC) strategies, which can help reduce onsite construction time, minimize traffic and environmental impacts, improve work zone safety, and deliver longer lasting and more durable bridges. ABC approaches include the application of technical innovations and management techniques. The decision to use ABC must be made on a project-by-project basis as each bridge location is unique, and factors constraining each project are different. Toward this end, FHWA developed a qualitative decision making framework called... 

Nowadays information technology has been applied in various fields. Enterprise Resource Planning (ERP) is one of the most important applications of IT in Iranian organizations. These systems can create competitive advantages for organizations. Companies which intend to use ERP systems have difficulties in selecting optimum system because of the diversity of such systems. On the other hand according to the considerable changes that the implementation of such systems at all levels of the organization willbring about, lack precision in selecting appropriate ERP systems leads to irreparable damage for the organization. This study attempts to resolve problems in selecting and implementing... 

Type-2 fuzzy sets are generalisations of ordinary fuzzy sets in which the membership grades are characterised by fuzzy membership functions. Here, we consider the problem of finding the distance between two interval type-2 fuzzy sets (IT2-FSs). We define the formulation of calculating the distance between two IT2-FSs based on a new definition of centroid for an IT2-FS and explain an algorithm for obtaining it. Then, based on our proposed distance formulation, we present a method to deal with fuzzy multiple attributes group decision-making (FMAGDM) problems. We also use two examples to illustrate the FMAGDM process of the proposed method. The method provides us with a useful way to deal with... 

The purpose of the research is to define and analyze the dominant organizational culture in Kish and to conduct a pilot research in Iran. Designed as a survey, the research employs the five cultural dimensions of Hofstede in organizations, and by different methodology, defines the ranking of each dimension. The sample consists of 254 employees working in two public and five private organizations on Kish-Island. In addition to define the ranking for each of the five dimensions, for the first time in Iran, the survey measures the ranking of long-term orientation, and shows differences between dominant culture in Iran and the Arab countries (opposed to Hofstede's recommendation). The...