Sharif Digital Repository

In this research, we consider the application of copulas in multivariate quality control problems. In particular, we consider two specific problems. The first problem concerns the situation where the normality assumption is rejected. In this case, copulas can be used as a flexible tool to define a broad range of multivariate distributions with different dependence structure as well as marginal distributions. The second problem concerns proposing control charts to monitor the dependence structure among quality characteristics. The proposed method not only produces an out-of-control signal when dependence structure among variables deviates from the specified one, but also can be used to... 

Towards basic-applied Research in the System Sciences fields, this Research has been to try to understand the behavior patterns and Functional Architecture of parasitic organisms and Use these in Social-Economic Systems. In this research four scenarios for parasite behavior were found and based on one of them, the recent "Financial Crisis in Greece" has been evaluated. The results show that the developed model, can be effective in similar conditions.
 

Semantic video analysis and automatic concept extraction play an important role in several application including designing content-based search engines, video indexing, and video summarization. Since constructing an appropriate summarized video requires extraction of internal video concepts, video summarization is considered as an application of semantic analysis. The proposed system contains three main stages. In the first stage, the shot boundaries are detected, then using the hidden Markov model (HMM), the video is segmented into larger semantic units, called “play-break” sequences. In the next stage, several features are extracted from each of these units. Finally, in the last stage, in... 

MIMO radar is a next generation radar which transmits arbitrary waveforms at each one of its apertures. It has been shown that design of waveforms for MIMO radars in order to synthesize a desired spatial beampattern, is mapped into a waveform correlation matrix (R) design in the narrowband case. Therefore, waveform design in MIMO radar for beamforming could be broken into two steps, namely correlation matrix design and waveform synthesis for achieving given R. As of now, given a desired beampattern or estimated location information of targets, calculating R has been modeled as an optimization problem like SDP. Also, in some special cases like rectangular beampattern, close form solutions for... 

Commute mode choice and number of non-work stops during the commute are jointly decisions that have interaction. If an individual chooses a vehicle for commute, regarding to restriction of that vehicle, could has some stops. On the other hand, if an individual need to has some stops, choose vehicle for commute with regarding to number of stops. In this study to consider interaction between these decisions we employed joint modeling frame work. The data used in this study are, drawn from origin-destination travels data of Shiraz-Iran conducted in 1997. To obtaining best fitting model, different copula functions have been used. Finally Frank copula is selected as the best copula for joint... 

Since expansion of communication technology, telecommuting has gained attention from transportation planners as an approach in field of demand management. In this research, joint effects of feasibility of telecommuting for the employees of each organization and the relevant frequency of employees have been evaluated by using the copula model as the most recent conventional way of developing a joint model since the last few years. The result of telecommuting acceptance is that after presenting the project to each organization, the head employer measures the appropriateness of the project for employees and if he reaches a consensus on the success of the project, the employees get involved and... 

The objective of this dissertation is to develop a model to monitor and project the long-term changes in meteorological drought under climate change at watershed scale. In this model, drought is defined based on joint precipitation-temperature values since negative correlation between precipitation and temperature implies that drier periods are often warmer, and therefore, the consequences of drought are more severe compared to low-precipitation periods with mild temperature. This is of particular importance considering global warming. To quantify drought, an indicator called precipitation-temperature deciles index, which is an extension of precipitation deciles index, is introduced. Copula... 

Like any other Information Communication Technology (ICT) solution, E-shopping alters shopping trip patterns in a city. Product internet searching is another ICT solution which affects shopping trip patterns in a city. At the first stage, by producing ordinal regression models, this study explores all factors which are effective in adoption and frequency of product internet searching and e-shopping. In the next step, rather than pre-imposing restrictive assumptions regarding dependence, this study determines the structure of dependency between product internet searching and e-shopping with two (adoption and frequency) joint models by implementing the copula-based approach. This study relies...