Sharif Digital Repository

Using revenue management in any industry can increase the profit. In aviation industries, due to the huge number of requests and travels for each airline, a revenue management system can lead to a good profit for the airlines. The first step in revenue management system is predicting the demand.In this article two models are developed using time series techniques, based on the information taken from one of the Iranian airlines in Tehran-Mashhad fly route.The first model is developed using ARIMA and seasonal-ARIMA models and the second one is based on the demand and price history, price in the day of prediction and the ARIMA model. The second model which is a combination of price, prior price... 

In Computer-Aided Process Planning, there are two ways of manufacturing called Variant Manufacturing and Generative Manufacturing. Variant Manufacturing is based on a data base from a part family for a project. The part family is made in a series of root sheets regarding the final form of the intended part. The data base is updated after the manufacturing of each part. In order to make the system intelligent, one can use the OPITZ coding system that specifies the geometrical form, geometrical details and part manufacturing operations in a 13-digit number. The aim of this research is to choose the best machining parameters according to time and cost, that, based on the basic principles of... 

Statistics is an essential part of decision making and management in all organizations if the needed information is correct and updated. Due to lack of suitable information systems, it needs rework and spend extra time to gather information. Information Technology is used to summarize organizational information. It supports management of organization to make decision for strategic planning, tactical planning and operational programming by creation, storage, retrieve and distribute correct information to managers. For implementing these systems, there are many solutions. Selecting each one depends on conditions and potentials. Implementing integrated systems is expensive task therefore large... 

Using an efficient method to manage inventory systems is always a challenging issue in supply chain optimization. In supply chains including perishable goods, it is possible to reduce waste and other costs by identifying uncertain demand patterns and managing inventory levels at different stages of the supply chain. Considering the uncertainty and complex conditions of supply chains in the real world, in order to create a suitable model to express these conditions, various uncertain factors must be considered, each of which affects the supply chain inventory level in some way. In this research, a multi-level perishable supply chain model with uncertain demand, lead time and deterioration... 

During recent years a variety of decision making models for project selecting and priorities have been developed. Most of these models used quantitative indicators for projects evaluating and focused on financial and economic indicators. In this project, a decision support system for project portfolio management in construction industry has been developed. The most important feature of this model that distinct it from others is its relationship with the organization's strategies. On one hand, this model focuses on the organization to ensuring that the projects selected for investment, meet the portfolio strategy and on the other hand, it focuses on project management to delivering projects... 

In today's world, decision-making has become one of the main problems and challenges for managers, despite the conflicting goals and the different scenarios. On the other hand, most existing decision-making methods are not applicable to all issues in different decision-making environments. Therefore, in this study, by presenting a new algorithm, these concerns have been reduced and a new method has been proposed using the concept of stratification recently introduced by Lotfi Zadeh. In the present study, a single system multi stratification and multi-system multi stratification are presented, which provide managers with an easier understanding and analysis of each system so that they can... 

A qualitative study has been conducted in order to identify evidence of bounded rationality in software engineers' career decision making. Tversky and Kahneman's heuristics and biases approach has been used as a theoretical framework of the study. The theoretical framework comprised four decision-making and judgment heuristics, i.e. availability, representativeness, anchoring and adjustment, and affect heuristic. The data were gathered through semi-structured interviews and analyzed using thematic analysis method. The final results revealed that software engineers did make use of heuristics in making career decisions. Several incidents of the use of availability, representativeness, and... 

Travel demand estimation is a complicated process as travel demand is highly influenced by uncertainties. These uncertainties can be analyzed in two levels: aggregate and disaggregate. Models in aggregate level are usually influenced by uncertainties in data insufficiency in some regions of data space because of non uniform distribution of input data. Uncertainties embedded in travelers’ perceptions of some influential variables on demand estimation (such as travel time) moreover affect these models. An expert-guided algorithm to incorporate expert knowledge into adaptive network-based fuzzy inference system for compensating data insufficiency and considering uncertainties inherent in... 

Considering the aggregation of software architecture design decisions, the decision on appropriate from, is important to the success of a software project. Hence, the software architects need reliable and accurate process for correct decision making which seeks to reduce risk and increase productivity. Furthermore, different stakeholders involved in the architectural design process and presence of cooperation between them for architecture decision making indicates the nature of collaborative activities related to architectural design. Effective collaboration among those involved in the design process not only will affect on the quality and accuracy of the architecture, but also accelerates... 

Airports are one of the most important elements of the aviation system that provide the ground infrastructure that is required for enabling or flight across the globe. Master Planning is currently the dominant approach to airport strategic planning. However, history shows that this approach can often result in costly mistakes. Because there are many stakeholders with conflicting objectives, deep uncertainty about the future, and many potential strategies, planners often narrow their scope by using a single forecast for the future, leaving out alternative strategies, and excluding stakeholders, resulting in a Master Plan that quickly becomes obsolete and may be opposed by some stakeholders.... 

In this research, a general model is proposed aiming at establishment of optimized application of Methane gas with maximum added value. That is, maximum added value of methane for different applications of methane including consumption as fuel, export and injection-to-wells are calculated and compared. Accordingly, results of this study are used for decision making regarding Iran’s most important gas reservoirs. In this study, maximum present net value of investment concerning comparison of petrochemical industry input and export to a number of selected countries in addition to injection in 20 years is calculated based on a specific discount rate. It is noteworthy that the scope of this... 

The case of rapid small satellite aerial launch by mother airplane has various applications; such as space experiment, weather monitoring, and getting information from the earth monitoring during natural disasters. In this method, the satellite and the launch vehicle will be carried up by mother airplane to the definite height; then, the launch vehicle will be released and flied - to the insert of satellite into the desired orbit. Aerial launch system success depends on a set of complex elements and their interactions. In the present study, first of all, the element interactions will be investigated by system engineering approach based on operational scenarios; then, a new approach for... 

The main goal of this research is to reduce aircraft design cycle period, by reducing the necessary number of design cycle iterations. The Design cycle period is one of the main characteristics of the design process and design cycle iterations play a major role in the design cycle period. To achieve the above mentioned goal, we present a mathematical model of iterations for the aircraft design process. This model describes the design coupled tasks as a discrete-linear time invariant dynamic system. This model also helps identify tasks which are the most important for generating iterations. This new method basically helps break information cycles that create iterations among important tasks.... 

In many biological populations, information about environmental conditions is acquired collectively, through information sharing among individuals, by exchanging signals. In order to achieve a better understanding of such systems, using methods borrowed from statistical physics, we introduce two mathematical models. First, a collective decision making model, for a community of individuals residing on a communication network, who live in an uncertain environment, in which individuals try to collectively find the environmental state. In the second model, a collective movement model, we consider a population of collectively moving individuals, in which individuals try to collectively find and... 

With the expansion of the use of information technology and public access to financial markets, the number of players in this field has increased and as a result, the nonlinear behavior of the market has become more complex than before. Due to this issue, investors need specific strategies to identify suitable assets for investment and also to determine the time of entry and exit to the stock market in order to make a profitable investment. Therefore, the purpose of this study is to form a stock portfolio as an asset and based on an integrated approach of fundamental and technical analysis using machine learning techniques. In this research, the stock data of Tehran Stock Exchange and OTC... 

By increasing the penetration of distributed generation (DG) technologies such as photovoltaiec, μCHP etc, power generation system is moving from a centralized network to a distributed scheme with different generation units at lower level of voltage.This trend will provide the opportunity for cosumers to make decision when and which source of energy to use, due to the owner’s objectives. Here, to investigate these aspects, we use the energy hub framework, considering different energy carrier networks, DGs and storage devices. In this thesis, we model and simulate an energy system containing three interconnected energy hubs, which serve as interface between suppliers and consummers. In an... 

In this study hybrid classification models by combining genetic algorithm and classifiers such as neural network and decision tree are presented and efficiency of these models is tested on 5 different databases against other proposed models in this area. This comparison shows that the model obtained by combining genetic algorithm and neural network obtains better results than other models. Afterwards this model is used as a decision support system in diagnosis heart disease and in addition to determining the parameters of neural network such as the number of hidden layers and the number of neurons in each layer, efficient features in diagnosis heart disease are also determined. Among the... 

Key conservation organizations to meet customer needs and attitudes of SCM is not only the ultimate goal of customer relationship that the final product delivers, but a sequence of suppliers in this work considers the integration of organizations involved in the synchronization process material, and financial information to improve the competitiveness of the supply chain are examined. The proper functioning of the supply chain , a key role in achieving sustainable success of an organization and its profitability goals, especially. In this regard, the establishment of a system of supply chain performance measurement in continuous improvement of its performance is recommended. In each of the... 

The aim of this research is to develop and implement a deep reinforcement learning algorithm for portfolio management in the Tehran stock market, which is considered an emerging market with distinct patterns compared to the stock markets of developed countries. In this study, in addition to the market price data extensively used in previous research, we leverage fundamental ratio data extracted from company financial reports, which have received less attention. Furthermore, the research scope is limited to stocks in the mining and metal industries to enable the utilization of specific industry features, such as susceptibility to global prices of a key commodity. The portfolio management... 

Cancer is refer to a class of diseases that create as the result of abnormal growth of cells and invasion of them to normal cells of human body, and annually cause the considerable percentage of death in the world. Because cancer can be considered as a complex system, various models presented to modeling and simulation of the behavior of it, using of different methods such as cellular automata, agent-based, game theory and other methods. Multi-agent simulation models as a special kind of agent-based models, is a method that used to simulate some real-world phenomena that usually contains many different components and interact using different and complex ways. Since the cells are located in...