Sharif Digital Repository

mazandaran cement co.( the second biggest cement company in Iran) is located in Mazandaran province north of Iran. Thesis is about the weakness and strength points of available maintenance strategy (which is mostly CBM) in this company and offers some remedies to enhance the current maintenance situation. Maintenance information is assessed over a period of two years in a row and turn into some informative charts and diagrams for easier exploration. Eventually, some solutions are suggested for omitting shortages in current maintenance strategy  

Retail stores are one of the members of each supply chain which connect end customers to the other parts of supply chain. Matching customers demand with product supply, is one of the most important duties of retail stores. There are a big variety of products in retail stores and also many new products continuously enter to the stores, in the other hand available spaces for displaying products are limited and keeping those products in the shelves and warehouses will cost. However the amount and location of displaying products in shelves, directly effect on customer demands. When deciding about shelf space allocation, all of these issues should be considered. In addition, inventory control is... 

Gas liquefaction is one of the main applications of Cryogenics science. Due to the unique properties of Helium, it is a strategic product in the world. Therefore, appropriate and applicable analysis should be used to investigate and optimize the Helium liquefaction cycles. In the current study, the goal is to find the optimal point with the help of energy and exergy analysis based on economic criterion, for the various parameters of Collins’ cycle. In order to simulate the cycle, a computer code is developed. First, sensitivity analysis of different parameters affecting the exergy efficiency and liquid fraction of the cycle has been done. Then, Artificial Neural Network and Genetic Algorithm... 

Business process management (BPM) is an approach which helps managers to gain success in their organization by becoming capable of identifying and developing their processes. Process improvement is a difficult and important step in BPM since modern organizations have a huge number of processes and activities with complex and complicated relationships and interrelationships. In this work our goal is to rank and prioritize processes based on operational limitations of the organization such as budget, human resources, consumer resources and also relationships among processes have been considered and finally develop a portfolio of processes which are vital and essential for improvement.... 

Social media can be helpful to people in vast areas, especially in queuing systems, in the real world there is remarkably unknown information like service time, average waiting time or average queue length to customers, thus people are likely to share their experiences to posterior customers who want to use the same service. This research examines the impact of user-generated reviews, on the performances of a Markovian queuing system, we assumed that customers are not aware of the service rate, therefore they will assist next customers by writing reviews about their service time they had experienced. We intend to examine the impact of information on queueing performance such as system... 

Heart disease is one of the major causes of death in all countries, especially developing countries. At the moment, using Image Processing methods as well as analysis of electrocardiographic signals, heart disease is diagnosed with the help of specialists. Applying artificial intelligence and machine learning methods, many studies attempted to provide models that are used to diagnose automatically the heart disease without the need for a specialist and only relying on the past data. But less is done on CTA images of the heart. Hence, in this thesis, a new method for image processing and a Multi Support Vector Machine (MSVM) classification for coronary artery disease detection based on CTA... 

Due to the vast application of networks in the modeling of problems, the analysis of networks has been gaining a noticeable importance in recent researches. There are some cases in which we are looking for nodes that are highly connected to other nodes. However, the detailed information of the network structure is not always available; or because of complexity, it is not possible to investigate whole network and pick high-degree nodes; or investigating the network completely is too time-consuming. In such cases, algorithms which do not need the whole network information play a significant role. Friendship paradox as a topological feature of graphs can be helpful in designing such algorithms.... 

Emergency Department (ED) overcrowding is one the most problems and challenges that every Emergency Department all over the world is facing with. This problem leads to some problems like prolonged waiting times and Length of Stay in Emergency Department. “Boarding time” is one of the most important ones, which is the time a patient spend for being transferred from Emergency Department to one of the Hospital Inpatient Wards. One important solution to this problem is “overflowing”, and it means allocating patients to an alternative ward rather than their primary ward. In practice, the overflowing process usually controlled in a myopic manner. Limited number of researches that focus in this... 

Computer video games have had a huge growth in recent years, and Dota 2 is one of the most popular video games and e-sports right now. In this research, Dota 2 drafting phase is studied by using stochastic processes and probabilistic models. This phase is modeled as a POMDP (Partially Observable Markov Decision Process) for the first time. Afterwards, the model is solved using data mining methods and machine learning algorithms. A large database of the game's match data is created, and six different machine learning algorithms are used to predict the match outcome based on the drafting stage. The prediction accuracy and power of these algorithms is compared, and finally, a program is... 

Market heterogeneity is an essential element in the strategic decision making of firms. Today, differences in urban structures, product varieties, and information availability have created new heterogeneities that deviate from the ones in the classic literature of marketing and industrial organization. Thus a new perspective is needed for analyzing the firms' decisions in these markets. In this thesis, we study the effect of heterogeneous markets on the pricing, location, quality, and product line introduction strategy of a firm to find the optimal reaction of a firm entering these markets. In this regard, we first assume that consumers are not only located at different places in the market... 

One of the main goals in large projects with multiple contractors is to reduce costs in various processes. The complexity of a large project, which is mainly due to the complexity of activities and the existence of interference between different phases and the lack of transparency of activities, can be added to the multiplicity of contractors and the difficulty of proper interface management.As regards that large projects with a large scope of work, have to use several contractors and this issue has a direct impact on increasing project costs, large project management becomes a major challenge that the application of appropriate knowledge, improving processes and skills and tools can play a... 

Cloud Manufacturing have been provided the proper context for efficient and effective using from distributed and various sources for agile and fast responsiveness to various customer demands. Product request from customers lead to define the operations in shop-floor levels that must be process by production equipment in shop-floors. The planning and scheduling problem of this activities have been most important challenge for decision makers. Therefore, the development of ways and methods can exploit efficiently from distributed resources and in confront of customer reqirement have been adaptive is most important. In this study an adaptive approach can be considered in terms of assigning the... 

Problem of 2-colorability of hypergraphs was introduced by Erd?os in 1963, and there are many results about this problem until now. In this thesis we consider this problem from the algorithmic viewpoint. In all of the algorithms we assume that the given hypergraph is 2-colorable and we want to color it. By using a simple construction, it was shown that for every r = 3, the problem of coloring of hypergraphs is as hard as the problem of coloring graphs. If NP ?= ZPP12, it is impossible to approximate the chromatic number of r-uniform hyhpergraphs with n vertices by a factor of n1-? for any fixed ? > 0, in time polynomial of n. In reference [KS03] a coloring algorithm with approximation factor... 

The success of oil recovery depends, among other factors, on the ability to provide reliable simulations of the reservoir performance. The reservoir dynamics are usually modeled by a distributed parameter dynamic system whose parameters represent the petrophysical properties of the reservoir. A proper characterization of those reservoir properties is fundamental for an accurate reservoir simulation. The petrophysical properties are highly heterogeneous and only a limited number of measurements are available at certain locations in the reservoir. Therefor, in ordet to obtain accurate prediction of the reservoir performance, it is essential to possess reliable estimates of the petrophysical... 

In this thesis, we study diffusive heterogeneous predator-prey system with Holling type-II functional response in the presence of harvesting in prey equation i.e.8>>>>><>>>>>: Δu = u a(x)u2 buv1 + mu ch(x) inΩ;Δv = v v2 +duv1 + muinΩ;@u = @v = 0 on @Ω,where Ω is a smooth bounded region in RN and a(x) is a nonnegative continuous function on Ω, with Ω0 a region such that Ω0 Ω and a(x) > 0on ΩnΩ0. We show that in the case of weak prey growth rate, i.e. less than the first eigenvalue of Δ in Ω0 with Dirichlet boundary condition,the system has a positive solution for the values of in a bounded interval and c > 0 sufficiently small. We also investigate the multiplicity of positive solutions... 

Clustered Regularly Interspaced Short Palindromic Repeats, or in short, CRISPR is a relatively new technology that enables geneticists and medical researchers to edit parts of the genome by removing, adding, or altering parts of the DNA. Initially found in the genomes of prokaryotic organisms such as bacteria and archaea, this technology can cure many illnesses such as blindness and cancer. A significant issue for a practical application of CRISPR systems is accurately predicting the single guide RNA (sgRNA) on-target efficacy and off-target sensitivity. While some methods classify these designs, most algorithms are on separate data with different genes and cells. The lack of... 

Prediction and calculation of shielding tensors of H, C, F and P nuclei of different molecules has been the subject of much research, because these nuclei have the greatest importance in NMR experiments. The optimum wave functions and calculation method were obtained using empirical models and factorial design. Based on preliminary experiences, the following four factors at two levels were selected: electron correlation, triple-ξ valence shell, diffuse function and polarization function. The wave functions for calculating gas phase 1H and 13C chemical shifts of various types of alcohols, amines and simple hydrocarbons were optimized using empirical model. The B3LYP/6-311+G wave function is... 

Estimation of physical parameters for solutions and mixed liqids are used widely in industrial applications. However, we can do these measurements with conventional laboratory analysis, but we always want to find an easy and quick method that use on-line measurements. In this study electrical properties of different water liquids and mixture samples in frequency stepwise range of 100-100000 Hz are measured by using a short cylindrical capacitive sensor and a measuring module (LCR-703).Operation of the capacitance measurement module for such probes is based on the auto-balancing bridge method.The effects of frequency and volume fraction on the electrical parameters and permittivity of mixed... 

The electrical conductivity of the solution has been one of the important physical quantities in many application. In this respect many probes and devices such as conductive sensors have been devised. In this study electrical properties of different water samples at frequency step range of 100-100000 Hz are measured by using the long cylindrical capacitive sensor and a measuring module (LCR-703). Operation of the capacitance measurement module for such probes is based on the auto balancing bridge method. Comparison of the measured capacitances and measured resistances for different water samples shows a decrease by increasing the measurement frequency. In another study the dielectric... 

In this study, with respect to previous projects, we focused on size reduction of hollow and endohedral fullerenes research reactors. For this reason, we set up two reactors having 1/2 and 3 liters volumes and then such parameters as pressure, reactor temperature, arc duration time, arc time interval and the working electrical current through the electrodes circuit, in both reactors were optimized. The reactors, 3- and 1/2-liter reactors were of types of horizontal and vertical, respectively. In this project spatial angle between two electrodes were also found as effective variable on fullerenes yield in the 3-liters arc reactor for the first time. We found that upon correction of the...