Sharif Digital Repository

Distribution of goods by vehicle routing with split delivery and effective usage of trucks are two important problems which are useful separately and could be applied for different kinds of depots with different trucks to satisfy customers’ demand. Combination of these two NP-hard problems can play a great role to decrease transportation cost. Complexity of this problem is so much that we cannot solve big-size problems by exact methods or branch and bound method in limited time. We introduce metaheuristics methods such as Tabu Search, Simulated Annealing and Ant Colony Optimization which have been presented before, concisely. We present various constraints in routing and distribution,... 

Since random access networks can work in distributed manner they have found variety of applications in wireless local area networks and wireless sensor networks. Throughput maximization and calculation of optimal parameters of such networks are subject of many research but most of these researches have ignored delay and suffer from high packet delay. We investigate and analyze delay in random access and solve the delay constrained utility maximization problem. We define network utility as a combination of throughput and cost of energy consumption and solve “access network optimization with link delay constraint”, and “cross layer optimization of transport and access layer with end to end... 

Network dynamics, environmental changes, increasing number of users and their demand have made it necessary to continuously evaluate and optimize the network performance. Self organizing networks (SON) were introduced to add this capability to cellular networks. Among the SON functions, Coverage and Capacity Optimization (CCO) and Load Balancing (LB) are the most important ones. These two functions working collaboratively allows the operator to improve the network performance in terms of coverage and capacity while minimizing cell saturation and user dissatisfaction across the network. In this Thesis, a Two-Stage Optimization Approach has been proposed that enables the network to consider... 

The value of data transmission has surprisingly increased in the past years. Years ago, transmission of a few by telegraph systems satisfied human needs. But the amount of data transmitted increases exponentially and that is where engineers face real challenges. In the first generation of mobile networks, the voice was transmitted using Analog technology but in the second generation it switched to digital systems. In third and fourth generation systems data rate and quality of service was increased. A big change from the third to fourth generation networks was being an all IP network, meaning everything including voice and data were transmitted in packet switched networks. This creates... 

Measuring flow rate in various industries is an operational challenge that requires to be accurate and fast to avoid wasting energy and money. Various flowmeters are employed in different industries using different principles and methods. Sonar flowmeters are one of the acoustic methods of fluid flow measurement, which do this by listening to the sound of the flow via arrays of sensors. Sonar flow measurement can be achieved by finding either the convection velocity of eddies or the speed of sound in the fluid. The first method is suitable for measuring single-phase flows, which is the subject of this thesis. This method needs a detailed study of turbulence. In the present work, this is... 

The growth of user traffic and appearance of new services, has changed architecture of mobile networks. Data flows have different requirments based on their services. Mobile platform should be able to recognize services and slice network resources based on them. Different approaches have been investigated using relevant standards and numerous articles. The focus of this thesis is on implement a platform based on fourth generation mobile networks that can differentiate between data flows according to their respective required QoS.We have implemented an IMS network and connected it to a mobile core network But IMS network just supports session-based services. We introduced a solution for non... 

For several years, self-organizing networks have been introduced by 3GPP to reduce the costs of mobile operators. Self-organizing networks, by introducing a kind of intelligence to the mobile network, will cause optimal performance and, as a result, reduce the operating costs of operators. Improving network coverage and increasing user data rates are always among the priorities of operators to increase profits and customer satisfaction. Coverage and capacity optimization is one of the most important functions introduced in self-organized networks. In this study, in addition to the coverage and capacity optimization function, the load balance optimization and the contradictory interaction of... 

Existence of heterogeneity in vital tissues of complex multicellular organisms like mammals, and fatal tissues like cancer on one hand, and limited access to biological properties of their components on the other hand, turn the study of these tissue traits to one of the most interesting fields in bioinformatics. One of the hottest subjects in this field is the recognition of functional components of these tissues by using bulk data extracted from the whole tissue.Almost every method that aims to achieve such a purpose, particularly using gene expression data, assumes that all of the cell types which constitute the studied tissue have a deterministic expression profile.In this thesis we... 

With the increasing complexity of the business environment and rising stakeholder expectations, responsible leadership has become a key topic in organizational leadership research. This study examines responsible leadership in an Iranian organization, where evidence of leaders’ accountability toward stakeholders was observed. Given that the concept of leadership responsibility varies across different contexts, this study adopts a qualitative approach and a case study method to explore the nature of this phenomenon within the Iranian business environment. Data were collected through semi-structured interviews with the CEO, vice presidents, senior managers, experts, and external business... 

The main purpose of this study is to evaluate the linkage between two constructs about teamwork activities. One of them is "self-leadership in teamwork", the extent to which a person could control and manage his thoughts and activities in teamwork. The other is "shared leadership orientation", which is about orientation of people to contribute in leadership processes. This linkage evaluated with consideration of "self-efficacy in shared leadership" as a moderator.
Questionnaires of self-leadership in teamwork and self-efficacy in shared leadership elicited from literature with a little change and shared leadership questionnaire developed in another study by the author.Questionnaires... 

Women are going to play more important roles in the economy of most countries including Iran. Hence, since the number of entrepreneurs among women is increasing, identifying characteristics and other factors that cause these group to be successful, is a critical issue. Studies show that entrepreneurs, especially women entrepreneurs, face numerous problems in their career. These problems are especially more demanding in societies with unique cultural attributes. Therefore, applying personal and managerial solutions in order to overcome these problems are necessary. On the other hand, researchers believe that one of the most effective and beneficial concepts helping entrepreneurs in their... 

The present study was performed aiming to identify the ethical dilemmas human resource managers confront with in Iranian project-based organizations as well as to trace out the underlying causes. “Ethical dilemma” refers to a decision making situation in which ethical considerations render all the alternatives inapt, thence making the decision making process ethically complex. First of all, a theoretical framework was developed based on the preceding research; then, the study was further conducted utilizing a qualitative research method with an exploratory approach. The data were collected using in-depth interviews and analysed using the theme analysis method. The corresponding interviewees... 

Using Distributed leadership framework while studying the leadership phenomena in teams, especially in educational environment, has received more attention by scholars in these years. Although the results of these researches indicated positive consequences mostly, the need for exploratory studies to identify situational and contextual factors in distributed leadership effectiveness has been mentioned. In other words, it has been suggested that the effectiveness of distributed leadership in teams may be affected by situational and contextual factors. In the current multiple case study, after the initial study of leadership and its functions in some schools of Sharif University of Technology,... 

The influence mechanisms of executive/non-executive board compostion on board’s attribution style have been explored. In two case studies, I have examined boards’ causal interpretation about a critical incident which had a significant impact on firm performance. A qualitative research approach has been taken in the case studies. Data was gathered through semi-structured interviews with all board members and was analyzied with the theme analysis method. According to the results, board of directors’ collective attribution formation process can be devided into three stages of members’ expression of information and facts at board meetings, forming the individual judgements of members and at... 

Career Orientations or career choices, can be affected by internal and external factors. External factors are the environmental conditions that the reward and the attractiveness of selecting a career choice are dependent to them. Internal factors include the needs of oneself from his/her job, his/her beliefs and his/her skills and competencies about the job. In this research the internal antecedents of managerial and technical orientations between programmers have been identified. On the other hand the perception of people about the compensation system as an external factor which can affect the mentioned relationships, have been analyzed. It seems that this is the first research which career... 

Voluntary turnover has direct and indirect expenses for organizations and for this purpose; it has one of the richest literatures in academic works. Due to the especial role of knowledge workers in organizations, these expenses in knowledge-based organizations are more important and more costly than that of other organizations. One of the latest theories in the field of voluntarily turnover was introduced by Lee and Mitchell (1994) that was named “Unfolding Model of Turnover” to describe the process of decision of voluntary turnover. This theory is distinguished from its similar theories from two main aspects: First, they introduced new elements like shock. Second, they introduced... 

The measure of success in a company is determined by a high performing workforce that demonstrates the competencies necessary to drive the business success, while meeting the organization's strategic goals. This is where competency-based human resource management becomes important. The main factor contributing to the above noted area is the identification of core competencies. There has been a lot of research in this area during the past few years. Each research demonstrates an approach for the development of critical human resource competency models in an organization. In order to determine the foregoing competency model, the early studies in this area have been focused on the distinction... 

The goal of this study was to realize how the younger generation's perceptions of the authenticity of senior managers in knowledge-based firms affects the components of their employer brand on social media. For this reason, the perceptions of managers' authenticity from the perspective of the younger generation on Instagram, as an example of social networks, was investigated in the first stage of the study. The mechanisms of effectiveness of the identified components of authenticity are sought in the second step, in shaping the components of the manager's organization's employer brand. To attain the research goal, an exploratory approach was taken conducted, and a qualitative research method... 

This research explores the impacts of the telework initiated by the outbreak of COVID-19, which is being called “emergent telework” in this research, on psychological well-being of teleworkers. As for the nature of emergent telework which is a new and unique phenomenon, a qualitative research is conducted. In order to do so, 15 in-depth interviews were held with employees from product teams of 11 organizations, and the interviews were analyzed using thematic analysis. General conditions of teleworking are identified in two categories named as “not working adjacent to coworkers” and “being away from the physical environment of the workplace”. Emergent telework, alongside the general... 

In this research study, the reciprocal relationship between Emergent States and Team Processes has been analyzed in boards of directors, by using case study method with semi-structured interview as the method of data collection and thematic analysis as the method of data analysis. This research was conducted on the companies which are active in Information Technology industries, their size is in the range of SMEs, and have passed the early startup stage and an external investor has joined the board. After thematic analysis, narrating each case’s story, and theoretical analysis on each case, the obtained results are demonstrated with discussion on both cases, introducing a theoretical model,...