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... 

Language Model plays a vital role in speech recognition systems. Restricting the search space, language models combine the result of words recognition phase with the assumptions gained from the rules and structure of words’ syntax (inflection and etc…), resulting into a more appropriate sequence of words as output. Since the language model for a specific language is not static and varies under the influence of different conditions, the problem of matching language model is being posed. In general, the aim of an adaptive language model is to offer a model capable of capturing all possible changes in the structure of words’ syntax, inflection and semantic structures. If the matching process... 

In this research, a Simulation-based Dynamic Traffic Assignment model based on parallel Processing is proposed. Dynamic Traffic Assignment has two key sub problems: Route choice modeling and Dynamic network loading. In route choice problem, a Type-II fuzzy system is proposed to model the complexities and ambiguities, which exist in the behavior of network users. The model can consider behaviors of network users in the forms of route choosing and route changing. In dynamic network loading problem, a Cellular Automata model is proposed as a microscopic simulator. Finally, In order to speed up the model and to use it in real time problems, the proposed Dynamic Traffic Assignment algorithm is... 

In developing countries, especially those which are importer of advanced technology in policymakers as well as decision makers face multiple options in the selection, acquisition, application, and development of technology fields. Any appropriate and on-time response to these issues with regard to the dynamics of the market is the one of essential challenges in the technology policymaking which is arrayed in this thesis. The term “Technology Intelligence" is a generic solution for dealing with such a challenge. This research is a part of the development process of the technology intelligence system in the national context which emphasizes the field of “Fuel Cell Technology” as the... 

An acinus is defined as the complex of airways supplied by one first order respiratory or transitional bronchiole. In this part, the replenishment of oxygen at the alveolar surface occurs by a combination of convective air flow with diffusion of oxygen in the air. So for studying gas exchange in the lung, modeling gas species transport and exchange in an acinus is important. Due to lacking direct measurements of the distribution of oxygen (or carbon dioxide) concentration in the acinus, several mathematical models have been developed and studied by numerical simulations. But in none of them the influence of breathing pattern and the role of blood flow in restricting the gas exchange rate have... 

The Barrier of the internal rotation around C-N bond in O-ethyle morpholine-4-carbotioate were calculated using dynamic NMR spectroscopy (DNMR) in DMSO solvent. 1H and 13C NMR spectra were recorded at different temperatures (295-350K). Band shape broadening patterns at coalescence regions were simulated to extract rate constants of NMR spectera. Transition state thermodynamic properties of internal rotation around C-N bond in O- ethyle morpholine -4- carbotioate are estimated: , , , . To assay reliability of the estimated values, transition state thermodynamic properties were calculated using PCM model at method and basis set B3LYP/6-311++G(d,p). Theoretical values of thermodynamic... 

Building simple and effective models are essential to many applications, such as building performance diagnosis and optimal control. Detailed physical models are time consuming and often not cost-effective. Black box models require large amount of training data and may not always reflect the physical behaviors. In this study, a method is proposed to simplify the building thermal model and to identify the parameters of the simplified model. For instance, predicting the next-24-hour load in a building is essential for the optimal control of heating, ventilating and air-conditioning (HVAC) systems that use thermal or cool storage technology. In the first phase of this study, equations for... 

One of the obvious features of financial markets is the spread of crisis across the markets, which is called contagion and realized in forms of return and volatility spillover. Using the daily data on the stock price from December 2006 through June 2010, this study aims to examine the presence and significance of these spillovers between Tehran and Dubai Stock Exchange, by a FIVECM technique. The FIVECM provides long-run equilibrium relationships between the returns in the markets and short-run dynamics of involved endogenous variables. Furthermore, it takes into account presence of fractionality in the time series’ integration. Our analytical framework, models the spillover effects in... 

In this project, two multiscale modeling procedures have been implemented to study the mechanical behavior of SWCNT/polymer composites. First, a new three-phase molecular structural mechanics/ finite element (MSM/FE) multiscale model has been introduced which consists of three components, i.e. a carbon nanotube, an interphase layer and outer polymer matrix. The nanotube is modeled at the atomistic scale using MSM, whereas the interphase layer and polymer matrix are analyzed by the FE method. Using this model, we have investigated the macroscopic material properties of nanocomposite with and without considering the interphase and compared the results with molecular dynamics (MD) simulations.... 

Nowadays, the essentiality of appropriate modeling languages has become evident, and with the introduction of new concepts such as domain-specific languages, the need for systematic research on designing and engineering new modeling languages has increased significantly. Several modeling languages have been developed and employed over the years, but the area of modeling languages still suffers from the lack of a proper framework: There is a strong need for an engineering framework that specifies the detailed steps of language development, the input and output artifacts of each step, the techniques applicable to each step, and quantifiable methods for quality measurement. From a unified point... 

Software Product Line is known as a process of developing family of the software together. The methods of building a software product line is trying to capture commonality and variety of this family of software and form a product line based on them. Commonality of this family of the software allows us reuse in every aspect of the development of software. Nowadays, software architecture as a one of the most important aspect of software engineering, plays major role in specifying the tasks and clearing the relationship between people. It can divide large and complex system to some sub-system and overcome complexity of the system. Software architecture forms a basis for communication among... 

Description logic is a family of knowledge representive languages which represents knowledge via propositional logic (first order logic) propositions and constructors and applies its services for reasoning and consistency checking. Nowadays description logic and its popular reasoner FaCT++ which applies tablue reasoning technique are widely used in applications such as semantic web and onthologies. Model checking is a technique for systems and models verification and to guarantee the accuracy of design. Given a model description and a specification formula, the model checker verifies the model against the specification and decides if the model satisfies the description or not. Main model... 

In the ship designing, it is preferable to access to a good performance in waves and low efficiency loss. Accordingly, modeling and estimation of added resistance would be an important issue. Added resistance in wave is an important part of ship's performance due to many technical and economic effects on the ship's performance. With understanding and awareness of the added resistance that comes from ship accident to the waves, we can reduce this parameter by changing in specifications and hull form of ships. Designers are also interested in optimizing the ship from this aspect. In previous works, added resistance in waves was obtained from experimental, numerical and analytical methods. In... 

Cognitive radio is a tool for optimal use of radio spectrum, not used by the primary users all the time. Two main features of a cognitive radio are cognitive capability and reconfigurability. An intelligent cognitive radio uses its cognition ability to identify the environmental parameters and makes future decisions based on this information. Then the reconfigurability is used to set the sending parameters to the calculated values in the cognition phase. Cogition phase consists of major steps; spectrum sensing, decision, mobility and handoff. Throughout this thesis we first propose a cooperative sensing scheme using algorithmic techniques based on sensors’ spatial information through... 

Vibrational modeling of a gas turbine considering simultaneous faults is considered. Faults including: unbalance, misalignment, and rotor crack are selected to be modeled. Oil film forces of hydrodynamic bearings are chosen as the supports of the rotor. Modeling starts with choosing an appropriate finite element model for the rotor which includes the effects of shear deflection, rotary inertia, gyroscopic moment, and rotor cross section variation. Modeling of unbalance is in fact a part of rotor finite element modeling. The forces that origniate form misalignment are computed using the static relations of a rigid coupling. Modeling of bearing faults along with bearing forces is performed... 

Advanced RISC Machines (ARM) are an example of a simple processor used to accomplish simple processing tasks in many applications. They can be found in PDA’s, mp3 players, and other portable electronic devices. ARM processors have small instruction sets and basic processor architecture, and they can be modeled in transaction level by SystemC. SystemC is one of many high level programming languages used to write hardware descriptive codes. We have chosen TLM in SystemC so that abstract data types can be used for higher level modeling and faster simulation. System architects and embedded software developers are accepting transaction level modeling into their design flow because it addresses... 

The available investigations show that gravity drainage mechanism in fractured reservoir make a high recovery factor in comparison with other mechanisms. In recent years, the forced gravity drainage assisted by gas injection is also introduced; despite of its importance there is no comprehensive modeling study in the literature. The fractured reservoir is simulated frequently by dual porosity models in which the transfer function is the key issue for this method of simulation. This study makes an effort by comparison of different transfer functions with fine grid simulation results of a single block model, in order to evaluate their ability for simulation of forced gravity drainage... 

Networked businesses refer to those businesses which establish flow of value between their customers through platforms. Networks create value by preparing the access of customers to each other and facilitating the interactions between them. Today more than 60% of fortune100 companies capture revenue through a network concept. The most important issue which makes networked businesses different from traditional businesses is a phenomenon named Network Effects. Network Effects is the relationship exists between the value of a network to its users and the number of users connected to the network. In this research reviewing literature and case studies of networked business area, we have found... 

Selection of appropriate acquisition mode for a required technology is one of the critical strategic decisions in formulating a technology strategy. Although a number of factors were found to be influential in the choice of technology acquisition mode, it still remains a void in the literature how to make a strategic decision, based on a huge set of those factors with the help of a systematic approach. This study deals with the selection of technology acquisition mode & method as a multiple criteria decision making (MCDM) problem. It tries to provide more appropriate solution for prioritizing technology acquisition modes through analytic network process (ANP), along with considering internal...