Sharif Digital Repository

This research intends to investigate the multi-skilled project scheduling problems (MSPSP) considering staffs’ dynamic efficiency. In doing so, a mixed-integer nonlinear programming (MINLP) model is proposed, considering the influence of personnel learning and forgetting on activities duration. The more the staff spends time on their various skills, the more learned and efficient they will be on that skill (according to personal learning curves) so that they can complete new tasks less costly and more quickly. Most project-based organizations want to maximize value by finishing the projects efficiently and developing their staff’s competence through projects. Inherently, any... 

Reinforcement learning is a learning method that uses reward and penalty feedbacks, having no information about the right action. In this method, agent gets the state of environment and selects an action among its permissible set of actions, regarding its policy and the given state. Environment, expresses an evaluation, in form of a reinforcement signal and a change in state, as a response for agent’s action. Afterward, the agent updates its policy considering received signal in order to maximize its long term reward. Reinforcement learning rapidly converges to the optimal solution, only if there are few states and actions, but there are lots of domains that consist of too many states and... 

Reinforcement Learning (RL) is a branch of machine learning that tries to improve agent’s behaviour through interaction with environment and receiving reinforcement signal. As the size of environment increases, decision-making would be more difficult and learning time will increase. On of the main approaches for decreasing learning complexity is to define skills. Skill is a behavioural unit consists of primitive actions. Humans learn and use a lot of skills in their life. Walking, eating, passing the door to reach kitchen and going to airport for travelling are examples of such skills that humans utilize them for daily activities. Agent can learn skills once and then uses them in other... 

Systems Thinking is a key to improve the quality of decision making in various situations such as social, political, economic and managerial ones. Systems Thinking is considered a foundation of Organizational Learning and currently has a crucial and cultivating role in the management literature. Therefore, it is now critical for organizations to have people within them who are able to think systematically. This need for possessing Systems Thinkers in organizations highlights the importance of the education of Systems Thinking. An evidence for this is the growing importance of Systems Thinking Education in the Systems Thinking Literature. On the other hand, one of the most important issues in... 

One of the main challenges construction industry face is the shortage of skilled labor. It is also one of the main reason of project’s delay. Many strategies including compensation payment, longer hiring duration and increase in wages has been proposed. Conventional scheduling assumes unlimited amount of resources or if consider the resource, is restricted to single-skilled resource. This is in contrast with real-world where workers may not be available at any time or they may possess a range of skills. Multiskilling is a workforce strategy that has been shown to reduce indirect labor cost, improve productivity and make the planning more realistic. Past researches proposed algorithms using... 

Multi-mode resource-constrained project scheduling problem (MRCPSP) is considered one of the most complex and most frequently applied problems in the science field of project scheduling and the science of operations research, which recently a new version of it called multi-skilled project scheduling problem (MSPSP) has emerged in research studies. The purpose of this new problem is to schedule activities with respect to precedence relationships and resource constraints of the workforce types with multiple skills, such that the requirements of any activity for a subset of skills must be met by the qualified members of the project. In this study, in addition to observing the constraints and... 

To maintain adaptability, businesses should anticipate changes in their environment. The commonly employed forecasting method within corporate circles is the bottom-up approach, which relies on historical data for projecting future trends. However, research suggests that this approach often falls short of accurately reflecting real-world events. This has led to the adoption of dynamic systems modeling, a technique grounded in the assumption of stable conditions. This method effectively replicates the system's current state, thereby assisting in predicting future behaviors over a longer timeframe. The dynamic systems modeling approach was employed in this study, underscoring the imperative... 

Construction is considered as a major industry with an important economic impact in every country because of its extensiveness, high working capital ratio, and rate of employment. The construction industry needs to incur expenses and take high risks. It's soundness is influenced by many factors, some of that are controllable, and some others are not. The stakeholders of construction projects try to maximize interests and reduce the cost and time of projects in every phase. Every year, a significant part of Iran’s national revenue is invested in construction projects and infrastructures. When construction projects become more extensive and complex, stakeholders are always looking for... 

In this millennium there has been a thought-provoking dispute over the inclusion of Critical Thinking (CT) programs into teaching syllabi; this inspiring challenge of change has led researcher to investigate the teachability and transferability of Critical Thinking. Thus, this study investigated whether explicit critical thinking instruction can foster critical thinking skills of in-service EFL teachers and enhance their disposition, perception and attitude. To fulfill the purposes of this study, California Critical Thinking Skill Tests (CCTST), EMI Critical Thinking Disposition Inventory, as well as perception and attitude questionnaires were utilized. The participants of this research were... 

In this research supply and demand factors regarding skill premium, ratio of revenue of college to non-college workers, in years 1984 to 2012 have been investigated. Three periods 1984 to 1995, 1995 to 2005 and 2015 to 2012 can be identified. In all three periods relative supply of college workers has increased. Demand in the periods have been constant, increasing and decreasing respectively and with the effect of demand has led to decreasing, increasing and decreasing trend of skill premium in these periods respectively. Share of low skilled sectors like construction, trade and agriculture in second period declined which led to increased demand for high skilled labor .An opposite effect... 

The evaluation and selection of human resources is one of the most important management issues in organizations, and the importance of this issue increases when the evaluation and selection is related to managerial positions. Among the many methods that exist for evaluating and selecting human resources; The assessment center method is more useful for selecting candidates for management positions. The assessment center includes behavioral simulation exercises and competency where trained assessors observe and record behaviors and score competencies. The purpose of this research is to analyze and examine the fit of the model and the internal structure of the evaluation center in a government...