Sharif Digital Repository

In recent years, the use of fiber reinforced polymer (FRP) jackets, as an external lateral confinement has found considerable attention in retrofitting and strengthening existing reinforced concrete (RC) columns in earthquake prone areas. The FRP composites have numerous advantages such as ease in application, high strength and stiffness-weight ratio, no corrosion and negligible changes in the member dimension. Most of previous studies have concentrated on evaluation of the effect of confinement with spiral bars or FRP composites, separately. However, in practice both types of confinements exist in strengthening RC columns.
This paper presents the results of a computational modeling to... 

Embedded systems usually need to have a Real-time function so that the time constraint has been one of the most essential attributes of these systems. In the design phase of these systems a scheduler must be presented by the designer so that the observance of system deadlines can be guaranteed( Hard Real-time Systems). Safety-critical applications not only must guarantee system deadlines despite the hard timing constraints in the presence of error, but also must operate correctly and tolerate the error. In some of these applications reducing power consumption is one of the most important objectives because of limited supply energy. The purpose of this project is to firstly study the methods... 

In this study, I examined a two-level supply chain with two-way information exchange in which both the manufacturer and the retailer will be informed of each other’s stock.In order to make use of this type of information exchange, the manufacturer and the retaile modify their single-level base-stock policy to a two-level, state-dependent base-stock policy.Later, I exerted the lost sale policy. And finally, I investigated the impact of this type of information exchange on the general chain criteria. Then, I point out the advantages of this method.
Applying the mentioned method reduces the total cost of system as well as decreasing the average amount of manufacturer’s inventory along with... 

Nowadays competition in business world has increased drastically. Under these competitive circumstances, it is the supply chains that compete against each other rather than individual firms. Accordingly trying to achieve integrated and synchronized management of activities within a supply chain has become inevitable. Recently researchers have found interest in a particular problem in a supply chain and that is to minimize inventory and routing costs in a supply chain. This problem is known as Inventory Routing Problem (IRP) and has been intensely examined in past few years. In this thesis we will try to expand this well-known problem in pricing dimension. We call this new problem “Inventory... 

Embedded system Project management , because of lots of unstable parameters in design and also diversity of the technical knowledge ,requires a complex and agile project management methodology. Whereas in these projects , different knowledge fields are applied (such as electronics ,telecommunication ,control and robotics) and software is an evitable part of these systems ,project managers can not be familiar with all aspects of the technical and professional in deep manner. Considering that usually ,the project managers of such projects are elected from professionals of hardware or mechanical sections and not in deep inception of software project management , this thesis focus on a new model... 

In this research, we study the differences between the centralized and decentralized approaches in a two-stage serial supply chain including a manufacturer and a retailer under the lost sale policy. The centralized approach results in optimal solution of the system and the decentralized one is based on Stackelberg game in which the manufacturer is the leader. The retailer uses the continuous review (r, Q) policy and the demand arrives according to the stationary Poisson process. In order to obtain the solution for two approaches, a set of computational steps are developed. Furthermore, we provide a numerical example and the corresponding sensitivity analysis to compare the two approaches.... 

The dynamic behavior of beams and rectangular plates on elastic foundation under the effect of deterministic and random excitations is investigated in the cases of controlled and uncontrolled systems. The equations of motion are developed in each case in both deterministic and stochastic states. In all cases, the eigenfunction expansion method is used to solve the obtained equations.Moreover, the classical linear optimal control algorithm with displacement-velocity is considered to achieve the required control efforts. The applied dynamic excitations are supposed as moving loads, moving masses accompanied with random lateral excitations of supports and the uniform distributed linear loading... 

Queuing systems and their optimization have always been an important concern of every society. It has been a long time that people understand that with quantifying the queues they are standing on, they can save great amount of money and time. Because of that fact, they have been studying these systems, and reached to the interesting conclusions. These researches have shown that there exist a couple of equilibriums in every queuing system, such as: speed-price and speed-quality equilibriums.Knowing these equilibriums along with modeling them will help us optimize queues. The importance of this optimization is its incredible effect on cost reduction in economical and social queues. In many... 

According to key importance of bridges in transportation system vital routes, a need to study and survey of bridges against destructive factors exist. Among these, bridges with concrete deck are widely used. One of the most important factors in destruction of these bridges is steel reinforcements corrosion and destruction of bridge deck. So in order to reduce the aggregation of reinforcements in critical sections and performance improvement of deck beams, a reinforcing substance which is not only resistant against corrosion but benefits from high resistance and stiffness is implemented.In this research the case studied bridge is simulated by finite elements software in two cases; reinforced... 

The experience from the performance of buildings during past earthquakes has shown that asymmetric buildings often sustain more extensive damages as compared to the symmetric buildings. The rules of seismic design codes about these buildings are based on investigation of single story buildings in the elastic range and they use rigidity eccentricity as main irregularity criterion. Inasmuch as during damaging earthquakes some lateral force resisting elements will not remain elastic and they reach yield, rigidity eccentricity will no longer be an appropriate parameter to represent the asymmetry of structure; thereby, in these building all centers of mass, rigidity, and strength should be paid... 

Memories are one of the main component in the embedded systems, and owing to their vulnerability to error, this part of system must be fault tolerant. Single error correction (SEC) codes are one of the most commonly used methods against sot errors. However, on the other hands as the technology scales, multiple bit upsets (MBUs) are becoming more likely to occur in the memories and the SEC codes have lost their effectiveness in fault coverage. Therefore a greater attention is devoted to the codes with the higher fault coverage such as single error correction/double error detection (SEC/DED) codes. These codes increase the delay, area and power consumption overhead. These parameters are the... 

In this research Feature Recognition technique for the 2.5D parts in Boundr Representation ( B-Rep ) solid modeling was used.
This method uses DXF file and convert the wire model to B-rep model to recognize the Face, Inner loop and Outer loop. The algorithm of recognition the Face, Inner loop,.. were prepared and a software (visual basic) was developed.In a case study a part with a protrusion, depression and a hole was recognized and then the effect of this method in comparison to the traditional methods on productivity was surveyed  

Separating colored points is one of the important problems in computational geometry. In separating colored points problems a set of colored points in Euclidean space are given that each color designates a set of certain data.Different problems can be defined in the colored points subject. Among them,separating colored points is studied in this thesis. It is supposed that two sets of blue and red points are given. It is desired to find the minimum number of rectangles that separate the blue points from the red points. It is demonstrated hat if P ̸= NP then there is no polynomial time algorithm for solving this problem. Then, a constant factor approximation algorithm is introduced and applied... 

Even though a considerable amount of research has been conducted on composite wall system during past years, very limited research has been reported on shear walls strengthened by steel plates. In 2008, the composite shear wall, which consisted of reinforced concrete wall, retrofitted by steel plates, attached to both sides of RC walls using mechanical connectors in form of shear studs, bolts or lateral ties tested under axial load and lateral force. In this research, seismic behavior of RC shear walls strengthened by diagonal strips of steel plates is going to be studied. The result will be compared with RC shear wall which fully covered by steel plates.The behavior of RC shear wall will be... 

Recently concrete filled steel tubular columns developed in the construction industry. In these types of columns, concrete and steel have efficient and complementary performance because of proper confinement provided by steel tube for concrete which leads to increase strength and ductility of concrete, also concrete prevents local and inward buckling of steel tube. CFST columns have several advantages over conventional reinforced concrete columns such as elimination of formwork and reinforcement, rapid construction, decrease in the column dimensions and saving extra floor space and also improvement in the load-carrying capacity, ductility and energy absorption ability. Despite the above... 

After positivists, that argue the structure and growth of scientific knowledge is rational, and constructivists, that argue science is based on irrational basis, analysis of structure and growth of scientific knowledge, in few decades ago, has developed from cognitive perspective. In this approach, i.e cognitive phase of philosophy of science, the role of concepts, that organized around hierarchies, become important. In current dissertation, we have considered views of paul Thagard, the cognitive scientist, about conceptual systems, and structure of science from cognitive approach. Thagard, postulating the truth of scientific developments, describes mental representations and processes in... 

3D-object modeling and its representation in computers are one of the interested fields in computer science and engineering and problems like object and environment modeling, representation, storage and physical interactions are some of the important problems in this field. Increasing the applications of the technologies like localization, machine vision and virtual reality made the 3D-object modeling and its related problems, like 3D-model extraction and reconstruction, a nowadays interested challenges and a variety of solutions such as time of flight sensors,
structured light, sonar sensors and multi-camera reconstruction are presented for it. Multi-camera solutions, just like the... 

Given a graph G with a set of terminals, two weight functions c and d defined on the edge set of G, and a bound D, a popular NP-hard problem in designing networks is to find the minimum cost Steiner tree (under function c) in G, to connect all terminals in such a way that its diameter (under function d) is bounded by D. Marathe et al. [1] proposed an (O(log2n);O(log2n)) approximation algorithm for this bicriteria problem, where n is the number of terminals. The first factor reflects the approximation ratio on the diameter bound D, and the second factor indicates the cost-approximation ratio. Later, Kapoor and Sarwat [2] introduced a parameterized approximation algorithm with performance... 

The subject of this thesis is a two-echelon inventory system with a manufacturer and multiple distribution centers (DCs) that satisfy the demand originating from multiple sources. Demand from each source follows an independent Poisson process. The transportation times between the manufacturer and the DCs are assumed to be positive which may require keeping inventory at both the warehouse and the DCs. Inventory in both echelons is managed using the base-stock policy. The manufacturer works with
M/M/c product system. The cost of demand fulfillment for each DC consists of inventory holding and backlog costs. The objective is to determine the optimal base-stock levels at the DC  

The present paper discusses the possibility of adding recycled polymer fibres to high performance concrete (HPC). Fibres used in this study were recovered from discarded car timing belts. To investigate different characteristics of the concrete specimens several destructive and non-destructive tests, such as compressive strength, modulus of rupture, flexural toughness, ultrasonic velocity and electrical resistance tests were carried out. In addition, slump flow tests were conducted on the fresh concrete. Experimental results from the study showed that the use of low percentages (up to 0.5%) of waste fibres improved the modulus of rupture and flexural toughness. Based on ultrasonic and...