Sharif Digital Repository

The focus of this research is to present a model to verify the acceptance of projects with time and cost dependency on the usage of equipments. Decision on these projects is based on a dynamic programming in which at each stage, the profit of available projects in this stage, equipment value and the best choice of future stage are decision keys. In other words, after the completion of a project, it should be decided between doing a project or selling the equipment and leaving the remaining projects. For each projects, there is a product network that includes projects jobs and operations. After accepting projects, equipments of the projects will not be renewed and the usage of the equipments... 

It is well known that the most rigorous method to assess the performance and to predict the seismic demands of a structure subjected to earthquake is nonlinear time history analysis. However, this technique is accompanied by complexities and difficulties in evaluating the seismic demands of structures and requires superior knowledge and skill. As a result, in recent years, nonlinear static analysis has been proposed in performance based design procedures. One of the primary assumptions of nonlinear static procedures is that the behavior of a structure with multiple degrees of freedom (MDOF) subjected to seismic ground motion can be estimated from the response of an oscillator with a single... 

The job shop scheduling problem is an important and applicable optimization problem and has been attracted by many researchers in recent decades. A huge amount of applications of job shop scheduling problem in industries and services has been found yet. During the last decade, the sequence dependent setup time constraint has been considered in many researches, but with respect to the knowledge of authors, very few of these researches have considered the inseparable setup. Furthermore, few of them have considered the release date assumption. In this thesis, the classical job shop scheduling problem and the inseparable sequence dependent setup time and release date constrained problem have... 

In the present thesis, A Computer software has been developed to evaluate technical and economic aspects of photovoltaic systems, off-grid and on-grid configuration, in urban areas where the electricity grid is accessible. As a case study the building of Energy Engineering faculty with annual demand of electricity in lighting section equals to 80048 kWh was considered. Regarding incident radiation and PV system characteristics with the aid of utilizability concept, a technical evaluation has been performed then life-cycle saving index was considered as a criterion for choosing an optimum nominal size of the system. Results show that for current electricity tariff of educational buildings ... 

Due to the growth of energy consumption the use of new technologies and efficient energy conversion is necessary. An example of efficient energy conversion technology is CCHP (Combined Cooling, Heating and Power). The aim of the present research work is to develop a model that could be applied for optimal design of a hybrid CCHP system which would be Solar Combined Cooling, Heating and Power (SCCHP). In order to do so,microturbine power system, cooling and heating equipment’s such as absorption system and heat exchanger and also solar collector have been considered as an integral part of the system. The objective of the application of the model has been to identify proper sizing of all... 

The train scheduling problem is one of the most important scheduling problems in the transportation systems. The goal of train scheduling problem is generating a feasible timetable which consists of train departure times and determining the best station to stop. Optimizing the railway capacity is one of the most important goals in train scheduling phase. The sequence of dispatching trains and stopping schedule are the main factors that can affect railway capacity on double track lines. In this thesis, a double-track train sequencing problem is studied in order to maximize the railway capacity, subject to a set of operational requirements. This research proposes a flexible flow shop... 

Minimally invasive procedures are diagnostic or therapeutic methods that cause minimal injuries and side effects for patients. PCI is a common minimally invasive procedure for diagnosis and curing of cardiovascular disorders. In this procedure, the surgeon can have access to the cardiac vessels by a flexible instrument. However, motion control of this instrument inside the patient's body relies on surgeon's skills and in some cases, is time consuming so that the toxic effects of radiation on patient and surgical team increases. Magnetic flexible instruments are suggested to address this problem. Nevertheless, motion control of the flexible instrument inside the body still has many challenges... 

The main goal of this project is to design and implementation of the tissue auto-grasping algorithm for a wristed laparoscopic instrument. In this algorithm, the difference between the pinch forces of two jaws was taken into account when the pull force direction corresponding to the rod instrument direction was changed. The term ‘Tissue auto-grasping’ means automatic adjustment of the pinch force corresponding to the pull force exerted on the tissue by the robotic surgical instrument, so that slip and exerting excessive force on the tissue are prevented. In this study, obtaining the pinch force is based on the proximal force-sensing technique. For this reason, the force model of wristed... 

Changes in the internal structure of engines for reducing fuel consumption has almost stopped. While changes in powertrain is a better way to reduce vehicle fuel consumption. Recently, infinitely variable transmissions or IVTs have attracted large attention of car manufacturers . In these systems, due to the continuous transmission ratio, engine speed is kept in a range which is the optimum fuel consumption speed range. Designing of these systems for each vehicle must be done according to the requirements of the vehicle and engine abilities. So, an exact model of engine fuel consumption for the design of these systems is required. One way of improving the accuracy of conventional models, is...