Sharif Digital Repository

Mixed-model production Lines manufacture or assemble more than one product with similar production characteristics or different models of a product on the same line. This level of flexibility in commodities is very important to face diverse customers' expectations. In this article, U-shaped, mixed-model, synchronous lines with stochastic task times are discussed in a cost-oriented perspective. In U-shaped, mixed-model, Simultaneous consideration of line balancing and model sequencing is essential because different models require different tasks with different task times and the sequence of models determine the models which is produced in each station in each cycle. This sequence affects the... 

Kanban inventory system has been applied as a tool of implementing lean production and just in time philosophy since three decades ago. By implementing kanban in supply chain which consist of suppliers , producers , distributors and consumers, real information of demands transfers upstream and materials flows downstream and integrated supply chain can be optained. Therefore a lot of mathematical models for optimizing kanban inventory system in supply chain has been developed to implement just in time philosophy and reduce total inventory cost in supply chain systems this research consist of two main section. In the first section , kanban and supply chain primary concepts are reviewed and... 

Transfer functions of some important classes of infinite-dimensional LTI systems contain semi-polynomials in fractional powers of Laplace variable , possibly in combination with delay terms or exponentials of fractional powers of . They can be observed in many systems and subjects such as biological systems, distributed parameter systems and heat flowing phenomena. Some appropriate theorems relevant to the subject of BIBO-stability are available for a large class of such systems, though many difficulties arise in applying them analytically. In this work, some parameters of the transfer functions of such systems (e.g., the coefficients of the numerators and denominators) are considered as... 

Let G = (V(G),E(G)) be a Himple graph. An independent Het in a graph iH a et. of vert.iceH no t\vo of thE-'m are adjacE-'nt. The C'ardinality of a rnaxirnnrn independE-'ut fet in agraph G is r-ailed the independence number of G and is denoted b:y a:( G). The ndependencE- polynomial of G, I(G, :r), iH dE-'fined a l:ill'l I(G.1:) = ik(G)x'l \vhere iA.(G) is the number of iwh-•pendent ::->etH of G of Hize k and io(G) = 1. Then-' is nother graph polynomial \Vhir-h is called the domination poJ:ynomial and is defined as·ollmvs. A dominating sE-'t of G is a set 8 of vertices of G so that every vertex of G is fither in 5 or adjacent to a vertex in S. The domination... 

With growth in using the Internet and entrance of online stores and internet banks to daily people life, security has become a vital part of this new world. This causes, industrial companies started to produce security devices such as fire walls for protecting network from outside attackers and Intrusion Detection/Prevention Systems (IPS/IDS) for detection of attacks inside network. IPS/IDS causes network overload due to requiring copy of packet or flow information. With introducing Software Defined Networking (SDN) architecture, there is a hope to solve the issue with combining IPS/IDS and SDN features. Therefore, we propose two novel approaches for fast network scanning and SYN Flood... 

Pulsating heat pipe (PHP) is a type of wickless heat pipe that has a simple structure and an outstanding thermal performance. Nanofluid is a type of fluifid in which nanoparticles are dispersed in a base fluid and has a better thermal conductivity in comparison with its base fluid. In this article, the performance of a nanofluid PHP is investigated. In order to simultaneously investigate the thermal performance and flow regimes in the PHP, a one-turn copper PHP with a Pyrex glass attached to its adiabatic section was used. A one-turn Pyrex PHP was also used to fully visualize flow patterns in the PHP. Our results showed that the material that a PHP made of and temperature of working fluid... 

The Chemiluminescence method is considered as one of the most widely optical methods that used for identifying combustion systems. In this study, the OH^* and CH^* Chemiluminescence signals were measured with the use of PMT detector and other optical equipments for a bunsen burner. Also the effect of equivalence ratio and flow rate on these signals have been investigated. The results show that with increasing flow rate, OH^* and CH^* signals increase linearly. By changing the equivalence ratio, both signals were maximized near stoichiometric condition (OH^* in lean side and CH^* in the rich side). Therefore, both OH^* and CH^* are considered as indicators of released heat rate. It was also... 

In present research, a cohesive based finite element model has been introduced to estimate median crack depth during mechanical machining on optical glasses. Development of the machining numerical model has been initiated by investigating the indentation process. Experimental results of this step have been calibrated primary numerical model which has been used in the scratch process. Due to differences between the scratch mechanism and indentation one, mathematical bases fracture formulas and cohesive relations have been developed. After extracting primary result, using them in the scratch model and developing the primary model, ultimately numerical model has been evolved to an abstract... 

In this thesis, we study the multiplicity of the Laplacian eigenvalues of trees. It is known that for trees, integer Laplacian eigenvalues larger than 1 are simple. Here we consider the multiplicities of the other (non- integral) Laplacian eigenvalues.We provide an upper bound and determine the trees of order n that have a multiplicity that is close to the upper bound (n-3)/2 , and emphasize the particular role of the algebraic connectivity.In continuation, let G be a graph and I be an interval. We present bounds for the number m_G I of Laplacian eigenvalues in I in terms of structural parameters of G. In particular, we show that m_G (n-α(G),n]≤ n-α(G) and m_G (n-d(G)+3,n]≤ n-d(G)-1, where... 

The rapid growth of e-commerce and home delivery has increased the number of vehicles on the streets. As a result of that, traffic congestion and, in return, air pollution have got worse. To prevent this trend, using electric vehicles is highly suggested, and in recent years, some companies have started using autonomous delivery robots. Since these robots can travel for a limited time, it is better to use them in conjunction with other vehicles, like vans. In this research, we propose a mixed-integer programming model to formulate a two-echelon time-dependent vehicle routing problem with simultaneous pick-up and delivery. In the first echelon, vans travel from a central depot to parking and... 

In this research, a cooperative terminal guidance algorithm has been derived for simultaneous multi-interceptor collision with a target. This algorithm is obtained using the combination of model predictive control method and differential game theory. One of the features of this method is the calculation of the optimal guidance command in the form of an explicit relationship. Another feature of this method is its resistance to disturbances due to the use of differential game theory. The first innovation of this research is the use of this hybrid method to create a guidance algorithm, even in the non-cooperative guidance problem. The next innovation is in creating a cooperative terminal... 

Managing the supply chain is a competitive necessity in today's global marketplace where differentiation between products and services means providing a total value package that can compete for an increasingly discerning and empowered customer. Today's view is one of integration. Supply chain management is the integrated management of business links, of information flows and of people. This research is based on a study conducted to introduce a reference model for Supply Chain integration. In that study, 10 drivers are introduced as keys for integrity in Supply Chain. The objective of this article is to discuss a method which has been developed to measure objectively and quantify the level of... 

According to increase of multimedia applications such as video surveillance and environment monitoring in Wireless Multimedia Sensor Networks (WMSN), energy conservation and prolonging network lifetime become increasingly important. Therefore, energy conservation and maximization of system lifetime are commonly recognized as a key challenge in the design and implementation of WMSNs. In these networks, nodes sense the area with high degree of correlation due to the overlapping Field Of Views (FoVs) and causes wasting network energy. We present “overlapped region detection clustering” as a new clustering method to reduce redundant video streams and overcome waste of the energy. We apply scene... 

In the intricate realm of supply chains, the ripple effect, akin to an abrupt storm, can jeopardize the stability and efficiency of the entire chain. This research aims to identify and prioritize the causative factors of this disruptive phenomenon, employing the Fuzzy Delphi Method. The Fuzzy Delphi Method is utilized in this investigation, as it possesses the capability of integrating expert knowledge with quantitative analyses. To construct the questionnaire, the results of previous studies were initially examined, and the influencing factors were identified. Subsequently, drawing upon the knowledge and experience of ten prominent experts from the "NAVABEHDASH" Organization (PANBERES), the... 

Due to the huge contribution of commercial transportation in creating pollutants, if various companies around the world are able to use electric vehicles, a big step will be taken in the direction of reducing pollution and expanding green supply chains. Despite the development of the infrastructure of electric vehicles and their use to transport goods and serve customers, this clean technology still faces many challenges.Among the weaknesses that researchers have been trying to deal with since the formation of electric vehicle routing is their low range of motion. After examining the way of using commercial electric vehicles, this research introduces the routing model of electric vehicles... 

A fullerene graph is a cubic and 3-connected plan graph that has exactly 12 faces of size5 and other faces of size 6, which can be regarded as the molecular graph of fullerene.In the irst part of this thesis we study some important deinitions and theorems whichused in the other parts.A matching of a graph G is a set M of edges of G such that no two edges of M sharean end-vertex; further a matching M of G is perfect if any vertex of G is incident with anedge of M. A matching M of G is maximum if |M| ? |N| for any other matching N in G. Amatching M is maximal if it is not a proper subset of some other matching in G. Obviously,any maximum matching in G is also a maximal matching. An... 

Distribution of goods by vehicle routing with split delivery and effective usage of trucks are two important problems which are useful separately and could be applied for different kinds of depots with different trucks to satisfy customers’ demand. Combination of these two NP-hard problems can play a great role to decrease transportation cost. Complexity of this problem is so much that we cannot solve big-size problems by exact methods or branch and bound method in limited time. We introduce metaheuristics methods such as Tabu Search, Simulated Annealing and Ant Colony Optimization which have been presented before, concisely. We present various constraints in routing and distribution,... 

In this work, we evaluate differernt tensor decomposition methods in application of fECG extraction from abdominal ECG recordings. After selecting proper tensor decomposition tool (Tucker decomposition) we propose a linear source separation algorithm based on a measure of quasi-periodicity. The quasi-periodicity is attained through the use of a constraint on a matrix factorization problem. In practice, we form a three dimensional ”tensor” by stacking the observation matrix and rough estimates obtained by both linear and non-linear subspace reconstruction methods. The method is applied to a database of electrocardiography (ECG) recordings, where rough subspace estimates of maternal and fetal... 

In this research, we propose a formulated approach to locate and allocate two level of a three-level closed-loop supply chain consist of a number of capable points production facilities, redistribution centers and customer clusters for multiple products in multiple time periods. Also, we consider environmental aspects in this supply chain network by taking into account an objective function, aside from cost objective function, in the template of emitted carbon dioxide. In this research for the first time we consider vehicles’ emitted CO2 different in each period which is a result of gradual depreciation of vehicles. In the end for the sake of validating model’s performance we developed few...