Sharif Digital Repository

In today’s competitive world, using an efficient forecast method is necessity for companies. To now, many forecast methods have been developed, but many of them have not an expected efficiency. In this research, we develop a new hybrid forecast method with application of forecasting retails demand. The hybrid method is the combination of ARIMA method and neural networks. To test the efficiency of the method we use the 96 weeks data of plastic containers demand. We also comprise the hybrid method with other forecast methods including naïve method, ARIMA method and neural network method by applying root mean square error and mean absolute percentage error indexes. In the case of plastic... 

Tunnel form structures have been proposed in building industry during 40 years for financial saving, suitable structural performance and seismic behavior, and the possibility of performance in an industrial form; and they have also been brought up as one of the innovative technologies of construction in Iran for a couple of years. So far, these structures have been subject to study by the researchers less than frame structures. In comparison to the common structures, evaluating the behavior of these structures is analyzable as two or three-dimensional elements. In this research, the nonlinear behavior of these structures has been simulated and evaluated by using three-dimensional elements;... 

In this research, effect process TOC in MRP system have been studied,therefore, first the hypothesis in TOC process and MRP system have been studied and generated. Afterward, whit the use of library and sydies the research guestions have been compiled. The society under studyis an aluminium oasts manufacturing daycust tabriz company. For surveying the memtioned company, samed documents hase been studied. After gathering all information and documents, and analyzing them, the result has been revealed. Therefore the effect of TOC and MRP process an production system has been comeout. At present situation, the mast crucial factors for suruival and compdtetion are ones couse the reduction of the... 

Price and warranty are two powerful marketing tool that can stimulate consumers’ purchase willingness. Therefore, producers must choose the appropriate price and warranty that can stimulate customers to purchase the quantity that will achieve the maximum profit. This study investigates optimal strategies for price and warranty length of a new product to maximize profit of a producer during lifecycle of the product. We consider both durable products and non-durable ones. Customers buy non-durable products many times but if we consider the planning horizon relatively short, each customer buys one product during the period. So, the market for non-durable products is static and for durable ones... 

When demand for a product is price sensitive, pricing and lot sizing decisions are interdependent. Similarly, when a product is highly perishable, the demand may need to be backlogged to avoid costs due to deterioration, i.e., perishability and backlogging are complementary conditions.In this thesis we stablish two economic production quantity models for deteriorating items under conditions of finite production, exponential decay and partial backordering and lost sale. Two joint pricing inventory control models are developed for the problem by employing different modeling approaches over an infinite planning horizon. In two models, customer is viewed to be impatient and the fraction of the... 

Pattern recognition in data streams using bounded memory and bounded time is a difficult task. There are many techniques for recognizing patterns but when we talk about data streams these algorithms became useless since there are no enough memory to store all data. In data stream model the entire data is not available at any time and we don’t have enough time processing each data.
In this thesis we consider current methods for recognizing patterns from a data streams. The goal pattern in this study was the minimum total area of k convex polygons encloses all data  

This set is an introduction to a method for studying Constant Mean Curvature Surfaces (CMC) and Minimal Surfaces with harmonic maps . In recent years , integrable systems approaches for the construction of CMC surfaces in R3 have been developed . One of them , using finite type solutions of the sinh-Gordon equation .Another approach to CMC surfaces was developed by J. Dorfmeister, F. Pedit, and H. Wu in 2006 . It is commonly called the DPW method. The Gauss map of a CMC surface is a harmonic map , and in the DPW method every such harmonic map can be obtained from some holomorphic potential in a loop algebra . This method gives a description of all immersed CMC surfaces in R3 . in this paper... 

In recent years, more attention has been paid to the development of lightweight concrete (LWC). Study of such this material had been marked due to more importance of use of it.It is now well known that in order to model cracks the finite element model is more suitable.The fracture of quasi-brittle material such as concreteincludesthe fracture process zone (FPZ).Cohesive zone model is considered the most common model used for FPZ modeling.Therefore, in this article the propagation of cohesive cracks inLWC is modeled using the extended finite element method (XFEM). In this study, modeling showed fastgrowth and propagation of cracks inLWC. Due to its cavities and pores, LWC shows to be more... 

concrete-filled steel tube offers many practical advantagescompared withconventional structural systems. The concrete infill provides stiffness and strength in compression and restrains local and global buckling. The inelastic deformation capacity of the CFT system is increased by the confinement of the concrete fill by the thin, ductile steel tube, and this significantly contributes to the seismic performance.
In this research, Formation and development of plastic hinges in CFST frames using pushover analysis was investigated. Different frames with rectangular and circular column and I beam weredesigned and Using nonlinear finite element analysis, interaction between steel and concrete... 

Reinforced concrete (RC) column in building often needs strengthening either due to defects in the column themselves, having to support higher loads than those foreseen in the initial design of the structure or as the result of ageing or accidental damage such as earthquake force. The use of FRP wrapping, steel caging or reinforce concrete jacketing for this purpose is now a common practice in many countries throughout the world. Even though a considerable number of researches have been conducted on retrofitting methods during past years, but very limited researches have been done to compare these methods. This research has investigated the effect of jacketing from different views. The... 

One of the methods to detect an unknown environment, is using the visual information about the environment. In this problem, we have an unknown two-dimensional environment consists of a set of edges and vertices that the geometric positions of vertices is not specified and only the combinatorial structure of the environment is available. In addition, certain information such as visibility of two vertices in the environment is known. The goal is to recognize the geometric shape of the environment with this information.This problem has many applications in Robotics particularly in dynamic envi- ronment where objects are moving.
In this thesis, we examine this problem in different conditions... 

Optomechanical systems have attracted much attention over the last decades, especially as a macroscopic lab for observing quantum mechanical effects . In this thesis , optomechanical quantum memories are studied . In p articularl , we study cooling of the mechanical resonator down to its ground state, which is the necessary condition to obtain a good quantum memory and also explore the limitations of cooling and storing protocols . Quantum state of light can be stored in the mechanical mode of the system by optomchanically induced transparency effect (OMIT) . This effect is formally equivalent to electromagnetically induced transparency effect (EIT) which is seen in an ensemble of... 

Modeling is one of the most important steps in analysis and design of structures. Most of the time behavior of floor diaphragms is assumed completely rigid in their plane in order to simplicity in practical design. Although this assumption leads to acceptable results in analysis and design of conventional buildings, erroneous results may assess in some particular buildings—for instance narrow buildings with stiff end walls. Accordingly, behavior of these buildings in future earthquakes opposes those were predicted in design phase, and they are so vulnerable since in-plane deflection of floor diaphragms are striking which cannot be ignored. This thesis investigates the significance of... 

Many industrial systems have on/off actuators. Traditionally, these systems are controlled using traditional control methods, like PID controller. The performance of this controller is not ideal for these systems, especially in term of transient response and power consumption. Due to the large number of constraints for these systems, to improve the performance of them, it is necessary to use the model predictive control technic. The decision variables of these systems are integer, hence it is necessary to develop the model predictive control method based on integer programming, which is the subject of this thesis. The main challenge in the development of this model predictive control method,... 

Temporary or permanent overload commonly occurs in soft real-time systems. In such situations,the scheduler cannot guarantee the completion of all tasks prior to their deadlines.Hence, some tasks are usually aborted before or during the execution with the aim of maximizing system utility. For this purpose, time-utility function (TUF) of tasks is used to determine how to maximize the accrual utility of the system. Tasks which can provide more utility are more preferable for execution. Previous works on utility accrual maximizing algorithms have not considered memory allocation in accruing utility of soft real time systems. In this thesis, we present an online scheme for multicore embedded... 

We design a new algorithm for clustering data streams in any fixed di- mension, that use the framework of core-set to summarize data, in order to reduce the complexity of computation. Clustering is to separate data into distinct sets called clusters, which objects in the same cluster has the most similarity and objects in the different clusters has the least similarity.This problem has many application in the areas such as: machine learning,image processing, financial and stock transactions. Data stream has recently emerged as an important concept because in many applications, data is inherently streaming over a network or the data base is extremely large and sequential access is way faster... 

Due to recent advancements and wide usage of location detection devices, huge amount of data are collected by GPS and cellular technologies which exhibits moving objects trajectories. Using this information, it is possible to track a set of objects over a long period of time, as happens for instance in studying animal migration. Always, in these situations it is undesirable or even impossible (due to process and storage limits) to store the complete stream of positioning data. Then, simplifying a trajectory as a data reduction technique is the option for resolving such problems. Moreover, there is an increasing interest in queries capturing ”aggregate” behavior of trajectories as groups like... 

This thesis is concerned with an optimal trade-off between communication overhead and the number and size of neighborhoods in a distributed optimal control technique for large-scale systems that is based on the Jacobi iteration and two-layer architecture for communication. Although this method efficiently reduces computational overhead, continuous and proper data transfer between subsystems that are very often far from each other, is required to achieve an acceptable performance. However, limited transmission bandwidth and short communication range result in significant communication overhead. This causes significant time latency between measurement and applied calculated control actions,... 

Given the increased competition in supply chains and enlargement of their scale along with increasingly significant role of distribution systems, design and optimization of novel systems with comprehensive approaches in a timely manner has become important more than ever. One of such modern, efficient systems is cross docking in which the distribution network is omitted and thus operations are carried out faster and the productivity is increased. In this system, processes like packaging is done in cross docking and the goods and products are directly sent to customers. This study investigates a long-term and a short-term approach to the design of in two distinct problems. In the first... 

Single-layer steel grid shell structures are a good structural solution to new buildings by specific properties that are required by long-span structures and provide at the same time the opportunity to produce immense verity of design shapes and free form architecture; complex curved surfaces expect to be covered with low weight material. A grid shell is essentially a shell with its structure concentrated into individual linear element in relatively thin grid compared to the overall dimension of the grid shell. This research investigates single-layer grid structures with emphasis on design of load details. The application of single-layer for transparent structures enhances use of glazed...