Sharif Digital Repository

In this paper, we study a supply chain problem where a whole seller/producer distributes goods among different retailers. Such problems are always faces with uncertainty with input data and we have to use various techniques to handle the uncertainty. The proposed model of this paper considers different input parameters such as demand, capacity and cost in trapezoid fuzzy forms and using two ranking methods, we handle the uncertainty. The results of the proposed model of this paper have been compared with the crisp and other existing fuzzy techniques using some randomly generated data. The preliminary results indicate that the proposed models of this paper provides better values for the... 

A new simple window function is presented, which for the same window order (M), has a main-lobe width less than or equal to that of the Hamming window, while offering about 2-4.5 dB smaller peak side-lobe amplitude. Furthermore, just like the Hamming window, it is computationally efficient for signal spectrum analysis; this is because of the fact that, the sum of window coefficients with its shifted version by M/2 samples (i.e. 50% overlap) is constant for the overlapped region. The new window is obtained by adding the third harmonic of the cosine function to the Hamming window, and finding the appropriate amplitudes of DC term, cosine function, and its third harmonic to minimise the peak... 

The maximally flat (MF) fractional delay (FD) filter which is in fact a Lagrange interpolator for uniformly sampled signals, has previously been shown to be equal to the scaled binomially windowed shifted version of the sinc function; the ideal interpolation kernel for band-limited signals. In this paper, another proof for this equivalence is presented. Unlike its counterparts available in the literature, the proof given here is neither strictly algebraic, nor deploys the explicit coefficient formulas of the MFFD filter. It follows a frequency domain approach based on the definition of this filter instead, and aims to provide more insight into the corresponding equivalence. © 2009 Elsevier... 

Problem statement: IEEE 802.11 Medium Access Control (MAC) protocol is one of the most implemented protocols in this network. The IEEE 802.11 controls the access to the share wireless channel within competing stations. The IEEE 802.11 DCF doubles the Contention Window (CW) size for decreasing the collision within contending stations and to improve the network performances but it is not good for error prone channel because the sudden CW rest to CWmin may cause several collisions. Approach: The research to date has tended to focus on the current number of active stations that needs complex computations. A novel backoff algorithm is presented that optimizes the CW size with take into account... 

Partial decoding scheme is a scheme in which each relay decodes only part of the transmitted message. Obviously, the achievable rates proposed by the partial decoding scheme subsume the achievable rates proposed by the full decoding scheme. The other motivation of using partial decoding scheme is that there are some special classes of relay networks such as semi-deterministic and orthogonal relay networks such that their capacities are obtained via this scheme. The authors propose a comprehensive partial decoding scheme based on regular encoding/sliding window decoding analysis to propose a new achievable rate for two-level relay networks. In contrast with the previously proposed methods,... 

Investigation of radiation heat transfer In vortex engine is an important and new phenomenon in combustion for scientists and combustion researchers. In this research some parts of the combustion chamber wall are insulated using Blanket as a high insulating material. The rate of radiative heat transfer to the chamber wall is calculated using temperature difference between inner and outer surface of chamber. In the experiments this parts are protected from direct contact with hot combustion media using quartz window. The luminous radiative transfer per volume of chamber and also volume of flame in a vortex engine are compared with that in a similar axial flow type engine. A detector sensitive... 

Many industries are involved in production and distribution of perishable products. On one hand, due to the short life cycle of these products, there should be more precaution on the issues related to supply chain planning including material requirement planning, production, transportation, etc. compared to the ones in other industries. On the other hand, as there is a fierce competition among various companies, the need for coordination in such activities is imperative, where the use of an integrated approach is justifiable. One of these coordination problems is how to integrate important operational decisions including production scheduling and vehicle routing problem; the most important... 

Despite many advances in optical character recognition in general, there are still serious challenges remaining in recognizing Farsi text. The main reason is the cursive nature of the letters in written Farsi, i.e., depending on the position of a letter within a word, it might join to its neighboring letters, which consequently changes the shape of the character. As a result, each letter can have up to four different character shapes. In addition to the problem of segmenting the characters, the increased number of characters makes the recognition task even more challenging. This paper introduces a complete framework for character recognition, including a method for segmenting the characters... 

In this paper, we investigate the performance of two strategies: simultaneous sliding window decoding (SimSlide) and simultaneous backward decoding (SimBack) when generalizing partial decode-and-forward to the relay networks. We show that these two methods yield the same achievable rates for relay networks but in comparison with sequential decoding, they yield higher rates. This is due to the fact that simultaneously decoding the different parts of the source message yields fewer bounds and this ultimately results a comprehensive and higher rate. We also introduce a special class of semi-deterministic relay networks and obtain its capacity by the proposed achievable rate  

Symmetric relaying is a method of relaying in which the relays can decode the message of other relays in the network in addition to the source message. In this paper an achievable rate is presented for a symmetric two-relay network based on partial decoding. The strategy make use of familiar techniques such as product binning, regular encoding/sliding window decoding and regular encoding/backward decoding. The proposed rate is shown to subsume the previously proposed rate for feed-forward relay network based on decode-and-forward. This rate is also used to establish the capacity of a generalisation of Aref network called 'semi-deterministic relay network with no interference at the relays'... 

In this paper, we propose a new algorithm for occlusion handling for object tracking in the crowded video scenes. The algorithm exploits the properties of undecimated wavelet packet transform (UWPT) coefficients and texture analysis to track arbitrary objects. The algorithm is initialized by the user through specifying a region around the object of interest at the reference frame. Then, coefficients of the UWPT of the region construct a Feature Vector (FV) for every pixel in that region. Optimal search for the best match is then performed by using the generated FVs inside an adaptive search window. Adaptation of the search window is achieved by interframe texture analysis to find the... 

Electrochromism (EC) is a unique property of certain materials that undergo an electrochemical-induced change in colouration. During the last decades, electrochromic materials (ECMs) have been applied in a variety of technologies ranging from smart windows to information displays and energy storage devices. More recently, ECMs have attracted the attention of the (bio)sensing community thanks to their ability to combine the sensitivity of electrochemical methods with the intuitive readout of optical sensors. Although still a nascent technology, EC-based sensors are on the rise with several targets (e.g. cancer biomarkers, bacteria, metabolites and pesticides), which have already been detected... 

The maximally flat (MF) fractional delay (FD) filter which is in fact a Lagrange interpolator for uniformly sampled signals, has previously been shown to be equal to the scaled binomially windowed shifted version of the sinc function; the ideal interpolation kernel for band-limited signals. In this paper, another proof for this equivalence is presented. Unlike its counterparts available in the literature, the proof given here is neither strictly algebraic, nor deploys the explicit coefficient formulas of the MFFD filter. It follows a frequency domain approach based on the definition of this filter instead, and aims to provide more insight into the corresponding equivalence. © 2009 Elsevier... 

Vehicular ad hoc networks (VANets) are special cases of mobile ad hoc networks (MANets) in which the mobility pattern is very different. Actually, the topology of the network in VANets changes more often and the variance of speeds is high. Such characteristics lead to fairness problem in VANets, considered in this paper. In fact, vehicles with different speeds have their different limited time to communicate with an access point (AP). This attribute adversely affects the chance of a fast moving vehicle in communicating with the access point. We propose a modified 802.11 DCF channel access scheme as a solution to the problem. The proposed scheme adjusts the probability of transmission at a...