Sharif Digital Repository

We study a variant of the problem of spanning colored objects where the goal is to span colored objects with two similar regions. We dedicate our attention in this paper to the case where objects are points lying on the real line and regions are intervals. Precisely, the goal is to compute two intervals together spanning all colors. As the main ingredient of our algorithm, we first introduce a kinetic data structure to keep track of minimal intervals spanning all colors. Then we present a novel algorithm using the proposed KDS to compute a pair of intervals which together span all the colors with the property that the largest one is as small as possible. The algorithm runs in O(n2 log n)... 

Using a proposed evolutionary algorithm, we have solved the inverse problem of finding the incident field on a high-aperture lens for generating a desired focused field, for the first time (to our knowledge). Further, we have achieved the global solution to the problem using this novel algorithm  

In this paper, we focus on the mixing matrix estimation which is the first step of Sparse Component Analysis. We propose a novel algorithm based on Expectation- Maximization (EM) algorithm in the case of two-sensor set up. Then, a novel iterative Bayesian clustering is applied to yield better results in estimating the mixing matrix. Also, we compute the Maximum Likelihood (ML) estimates of the elements of the second row of the mixing matrix based on each cluster. The simulations show that the proposed method has better accuracy and less failure than the EM-Laplacian Mixture Model (EM-LMM) method. copyright by EURASIP  

The utilization of the limited resources of a multiprocessor or multicomputer system is a primary performance issue crucial for the design of many scheduling algorithms. While many of the existing parallel machines benefit from a regular product network topology, almost none of the previous resource placement techniques have come to recognize and exploit this Inherent regularity. This paper introduces some novel algorithms for deriving resource placement schemes in product networks based on the assumed perfect resource placement in their underling basic graphs. © 2007 IEEE  

Both governments and health-related organizations must immediately act after a natural disaster happened, i.e., providing essential equipment and medicines to injured people as soon as possible and adequately. To achieve this goal, planning the distribution and the inventory of crucial items during a scenario of disasters, a relief supply chain network with four echelons, namely suppliers, warehouses, disaster locations, and medical centers, is designed. In this work, a bi-objective nonlinear mathematical model that follows two main concerns is proposed. First, we wish to minimize the supply chain costs in terms of both the traveling time between echelons and the inventory costs. Second, we... 

The utilization of the limited resources of a multiprocessor or multicomputer system is a primary performance issue which is crucial for the design of many scheduling algorithms. While many of the existing parallel machines benefit from a regular product network topology, almost none of the previous resource placement techniques have come to recognize and exploit this inherent regularity. This paper introduces several novel algorithms for deriving resource placement schemes in product networks based on the assumption of perfect resource placement in their underling basic graphs. Our techniques use known schemes for the basic networks as their building blocks for deploying the resource... 

Analyzing the features of the chromosomes can be very useful for diagnosis of many genetic disorders or prediction of the possible abnormalities that may occur in the future generations. For this purpose, karyotype is often used which to make it, there is necessary to identify each one of the 24 chromosomes from the microscopic images. Definition and extraction of the morphological and band pattern based features for each chromosome is the first step to identify them. An important class of the morphological features is the location of the chromosome's centromere. Thus, centromere localization is an initial step in designing an automatic karyotyping system. In this paper, a novel algorithm... 

Handling recurring concepts has become of interest as a challenging problem in the field of data stream classification in recent years. One main feature of data streams is that they appear in nonstationary environments. This means that the concept which the data are drawn from, changes over the time. If after a long enough time, the concept reverts to one of the previous concepts, it is said that recurring concepts has occurred. One solution to this challenge is to maintain a pool of classifiers, each representing a concept in the stream. This paper follows this approach and holds an ensemble of classifiers for each concept. As for each received batch of data, a new classifier is created;... 

Needle insertion into the soft tissue has been the subject of many studies during the last decade, while needle control has become a crucial training tool, evaluating surgeon's skills in such critical incision. This study considers a model-based dynamics equation for the needle movement through the soft tissue. In the proposed model, the force distribution along the needle shaft is estimated through the use of tissue deformation data and tissue model. A novel algorithm for the needle control simulation is also proposed based on the developed dynamics equation of the needle movement. To point out the role of mechanical properties of the soft tissue, an inverse dynamics control method is used... 

One of the most important issues in cognitive radio networks is to guarantee quality of service (QoS) constraints for primary users. In this paper, a relay-based cognitive radio network is considered in which secondary users compete in a selfish manner to use a relay to improve their utility function, while maintaining interference at the primary receiver to be lower than a certain threshold level. This problem is modeled as a non-cooperative game and by using a proper pricing function in the definition of the utility function, it is shown that despite the selfish behavior of the users, Nash equilibrium (NE) with sub-optimum property is achieved. A distributed and novel algorithm to update... 

Over the time, multistaging has proved to have some great benefits such as less electrical usage, so, nowadays; optimization of the electrical power usage in centrifugal compressors is an important issue to lead to the least usage of power. In this paper, we present a novel algorithm that provides this desire; it also shows different arrangement of the stages for the considered compressor. Simple single-stage compressor pressure ratio is normally limited by constraints of both aerodynamic and structural types. Reaching to minimum power leads to the least usage of electrical power. In this paper, we utilize theoretical relations which are extracted and have been presented a novel numerical... 

In this paper, we address the matrix completion problem and propose a novel algorithm based on a smoothed rank function (SRF) approximation. Among available algorithms like FPCA and OptSpace, there is no solution that can simultaneously cover wide range of easy and hard problems. This new algorithm provides accurate results in almost all scenarios with a reasonable run time. It especially has low execution time in hard problems where other methods need long time to converge. Furthermore, when the rank is known in advance and is high, our method is very faster than previous methods for the same accuracy. The main idea of the algorithm is based on a continuous and differentiable approximation... 

The utilization of the limited resources of a multiprocessor or multicomputer system is a primary performance issue which is crucial for the design of many scheduling algorithms. While many of the existing parallel machines benefit from a regular product network topology, almost none of the previous resource placement techniques have come to recognize and exploit this inherent regularity. This paper introduces several novel algorithms for deriving resource placement schemes in product networks based on the assumption of perfect resource placement in their underling basic graphs. Our techniques use known schemes for the basic networks as their building blocks for deploying the resource... 

Wavefront shaping using spatial light modulator (SLM) is a popular method for focusing light through a turbid media, such as biological tissues. Usually, in iterative optimization methods, due to the very large number of pixels in SLM, larger pixels are formed, bins, and the phase value of the bins are changed to obtain an optimum phase map, hence a focus. In this study an efficient optimization algorithm is proposed to obtain an arbitrary map of focus utilizing all the SLM pixels or small bin sizes. The application of such methodology in dermatology, hair removal in particular, is explored and discussed. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only  

Evolutionary Algorithms are vastly used in development of rule based classifier systems in data mining where the rule base is usually a set of If-Then rules and an evolutionary trait develops and optimizes these rules. Genetic Algorithm is usually a favorite solution for such tasks as it globally searches for good rule-sets without any prior bias or greedy force, but it is usually slow. Also, designing a good genetic algorithm for rule base evolution requires the design of a recombination operator that merges two rule bases without disrupting the functionalities of each of them. To overcome the speed problem and the need to design recombination operator, this paper presents a novel algorithm... 

Noise reduction is a major concern in digital image processing systems, which have been investigated by several techniques. One kind of important noises in images is known as Salt & Pepper, which may have different causes. In this paper a new approach for eliminating this type of noise is presented. The approach is different from all previous works in this field, and is based on classification. More precisely, it tries to classify pixels of an image to one of two categories: noisy or not noisy. Afterward, it employs a median filter for pixels which have been classified as noisy, and remains others unchanged; hence, edges and other fine details are kept. Experimental results show this... 

This paper describes a novel adaptive out-of-step detection algorithm based on dissimilar measurement approaches. Two superimposed measurements enable the algorithm to detect fast as well as slow power swings. Both methods recognize power swings right from the beginning of the swing impedance movement. The first principle is based on continuous rate-of-change measurement of the traveling swing impedance. The second method continuously monitors the speed and the shape of the swing impedance trajectory. The algorithm detects extremely high swing frequencies of up to 7 Hz and maintains functionality under single-pole open conditions, i.e. auto-reclose dead time. The associated distance relay... 

Dimension reduction techniques for text documents can be used for in the preprocessing phrase of blog mining, but these techniques can be more effective if they deal with the nature of the blogs properly. In this paper we propose a novel algorithm called PostRank using shallow approach to identify theme of the blog or blog representative words in order to reduce the dimensions of blogs. PostRank uses a graph-based syntactic representation of the weblog by taking into account some structural features of weblog. At the first step it models the blog as a complete graph and assumes the theme of the blog as a query applied to a search engine like Google and each post as a search result. It tries... 

This paper presents a novel algorithm for matching image interest points. Potential interest points are identified by searching for local peaks in Difference-of-Gaussian (DoG) images. We refine and assign rotation, scale and location for each keypoint by using the SIFT algorithm. Pseudo log-polar sampling grid is then applied to properly scaled image patches around each keypoint, and a weighted adaptive lifting scheme transform is designed for each ring of the log-polar grid. The designed adaptive transform for a ring in the reference keypoint and the general non-adaptive transform are applied to the corresponding ring in a test keypoint. Similarity measure is calculated by comparing the... 

Non Line of Sight (NLOS) propagation is a challenging issue which cause large errors in wireless localization systems. NLOS is especially a dominant source of errors in metropolitan area wireless networks like cellular ones. We discuss our algorithms within cellular network terminology. This paper contributes two novel algorithms. The first algorithm is to extract the NLOS state of base stations and the second one is a correction algorithm to enhance the measurements accuracy. Our introduced algorithms can easily operate with other wireless localization algorithms and reduced NLOS error. These algorithms are proposed for network-based localization because of the amount of calculation