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Search Results: 1 - 10 of 401 matches for " Farzad Hessar "
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Minimum Energy Source Coding for Asymmetric Modulation with Application to RFID
Farzad Hessar,Sumit Roy
Mathematics , 2013,
Abstract: Minimum energy (ME) source coding is an effective technique for efficient communication with energy-constrained devices, such as sensor network nodes. In this paper, the principles of generalized ME source coding is developed that is broadly applicable. Two scenarios - fixed and variable length codewords - are analyzed. The application of this technique to RFID systems where ME source coding is particularly advantageous due to the asymmetric nature of data communications is demonstrated, a first to the best of our knowledge.
Capacity Considerations for Secondary Networks in TV White Space
Farzad Hessar,Sumit Roy
Computer Science , 2013,
Abstract: The so-called `TV white spaces' (TVWS) - representing unused TV channels in any given location as the result of the transition to digital broadcasting - designated by U.S. Federal Communications Commission (FCC) for unlicensed use presents significant new opportunities within the context of emerging 4G networks for developing new wireless access technologies that meet the goals of the US National Broadband Plan (notably true broadband access for an increasing fraction of the population). There are multiple challenges in realizing this goal; the most fundamental being the fact that the available WS capacity is currently not accurately known, since it depends on a multiplicity of factors - including system parameters of existing incumbents (broadcasters), propagation characteristics of local terrain as well as FCC rules. In this paper, we explore the capacity of white space networks by developing a detailed model that includes all the major variables, and is cognizant of FCC regulations that provide constraints on incumbent protection. Real terrain information and propagation models for the primary broadcaster and adjacent channel interference from TV transmitters are included to estimate their impact on achievable WS capacity. The model is later used to explore various trade-offs between network capacity and system parameters and suggest possible amendments to FCC's incumbent protection rules in the favor of furthering white space capacity.
Real-Time Impulse Noise Suppression from Images Using an Efficient Weighted-Average Filtering
Hossein Hosseini,Farzad Hessar,Farokh Marvasti
Computer Science , 2014, DOI: 10.1109/LSP.2014.2381649
Abstract: In this paper, we propose a method for real-time high density impulse noise suppression from images. In our method, we first apply an impulse detector to identify the corrupted pixels and then employ an innovative weighted-average filter to restore them. The filter takes the nearest neighboring interpolated image as the initial image and computes the weights according to the relative positions of the corrupted and uncorrupted pixels. Experimental results show that the proposed method outperforms the best existing methods in both PSNR measure and visual quality and is quite suitable for real-time applications.
A GOST-like Blind Signature Scheme Based on Elliptic Curve Discrete Logarithm Problem
Hossein Hosseini,Behnam Bahrak,Farzad Hessar
Computer Science , 2013,
Abstract: In this paper, we propose a blind signature scheme and three practical educed schemes based on elliptic curve discrete logarithm problem. The proposed schemes impart the GOST signature structure and utilize the inherent advantage of elliptic curve cryptosystems in terms of smaller key size and lower computational overhead to its counterpart public key cryptosystems such as RSA and ElGamal. The proposed schemes are proved to be secure and have less time complexity in comparison with the existing schemes.
A Fixed Point Method for Convex Systems  [PDF]
Morteza Kimiaei, Farzad Rahpeymaii
Applied Mathematics (AM) , 2012, DOI: 10.4236/am.2012.330189
Abstract: We present a new fixed point technique to solve a system of convex equations in several variables. Our approach is based on two powerful algorithmic ideas: operator-splitting and steepest descent direction. The quadratic convergence of the proposed approach is established under some reasonable conditions. Preliminary numerical results are also reported.
Groundwater Quality Assessment Based on WQI and Its Vulnerability to Saltwater Intrusion in a Coastal City, Iran  [PDF]
Salman Tavassoli, Farzad Mohammadi
Journal of Geoscience and Environment Protection (GEP) , 2017, DOI: 10.4236/gep.2017.56010
Abstract: The purpose of this paper was to assess the quality of groundwater in Behshahr (Iran) based on water quality index (WQI). Sixteen water samples from this coastal aquifer were collected and analyzed to study physico-chemical parameters such as pH, hardness, chloride (Cl), electrical conductivity (EC) and total dissolved solids (TDS). The results showed that the annual average of TDS value increased by 343 mg/l between 1999 and 2015 due to anthropogenic activities. According to WQI, it was concluded that the groundwater quality degraded over the last sixteen-year period so that the percentage of samples identified as “good water” decreased by 18.5% and on the other hand, alas, the percentage of “poor water” quality soared by nearly 12.5%. Correspondence of WQI distribution diagram with that of chloride-bicarbonate ratio attests to the significant contribution of saltwater intrusion to groundwater quality deterioration in this area.
Landslide Hazard Mapping of Nagadhunga-Naubise Section of the Tribhuvan Highway in Nepal with GIS Application  [PDF]
Arjun Raj Pandey, Farzad Shahbodaghlou
Journal of Geographic Information System (JGIS) , 2014, DOI: 10.4236/jgis.2014.66059
Abstract: The aim of this project was to prepare and study a hazard map of Nagadhunga-Naubise section of the Tribhuvan highway. This section lies in the Middle Mountain region of Nepal. For the preparation of the hazard map of the corridor three steps, initial study, field investigation, and data analysis and presentation were carried out. In the initial study, the collection of available data and review of the literature were done. The base map was then prepared from the topographical map. In the field investigation step, all information and maps prepared earlier in the initial study were verified by field check. In the final step, prepared and verified data were then analyzed for the hazard mapping. Topography (gradient, slope shape and slope aspect), geology, drainage and land-use were considered to be the major influencing factors in the slope stability. Pre-assigned hazard rating method was used for hazard mapping of the study area. The area was divided into equal facets. Then ratings of responsible factors to the hazard were assigned to each facet and overlaid based upon a predetermined rating scheme. Total estimated hazard was the sum of these ratings for each overlay. Hazard map was prepared by using three categories as low hazard, medium hazard and high hazard. The Geographic Information System (GIS) was the main tool for the data input, analysis, and preparing of the final hazard map. The hazard map showed the areas of different hazard potential classes of; “low” with 32% portion, “Medium” with 51%, and “high” with 17% portion.
Evaluation of TB Patients Characteristics Based on Predictive Data Mining Approaches  [PDF]
Farzad Firuzi Jahantigh, Hakimeh Ameri
Journal of Tuberculosis Research (JTR) , 2017, DOI: 10.4236/jtr.2017.51002
Abstract: According to the World Health Organization, Tb is the biggest cause of death among the infectious diseases. Due to the high percentage of people with tuberculosis infection and the high number of death among these patients, this study is a prospective study aimed to categorize and find the relationship between different clinical and demographic characteristics. The study was conducted on 600 patients from Masih-e-Daneshvari tuberculosis research center during 2015-2016. The K-Means clustering data mining algorithms and decision trees are used to perform the categorization and determine common indicators among patients. 2 clusters according to Dunn index were chosen as the optimal clusters. Common factors between clusters are provided in detail in the findings section. According to the results of this study, the most important factors identified by the clustering include hemoglobin, age, sex, smoking, alcohol consumption and creatinine. The RBF neural network tree has 98% accuracy. According to the results of this study, the most important factors identified are sex, smoking, alcohol consumption and WBC, albumin.
Asymmetrical Gating with Application on Maneuvering Target Tracking
Farzad Hashemzadeh
Applied Computational Intelligence and Soft Computing , 2012, DOI: 10.1155/2012/670485
Abstract: A new asymmetrical gate with application in target tracking is proposed. Proposed gate has asymmetric shape that has large probability of target detection in the gate and has more advantages compared with elliptical gate. The gate is defined as the region in which the tracked target is expected to exist and just observation vectors in the gate are used as target detection. An analytical method to compute optimal size of gate is proposed and recursive estimation of asymmetric parameters of gate are studied. Comparison between proposed gate and conventional elliptical gate showed the efficiency of the proposed method in maneuvering target tracking applications and simulation results showed the proficiency of the proposed method. 1. Introduction Tracking is meant to be the estimation of the true values of specifications of target motion, such as the position and velocity, based on the n-dimensional observational vector by the sensors [1–3]. One-dimensional observation vectors are obtained in a direction-finding setup observing just the azimuth angle [4]. Two-dimensional observation vectors are obtained in optical sensors observing the azimuth angle and elevation angle, or in radars observing the range and azimuth angle. Historically, PDA (Probabilistic Data Association) [5], JPDA (Joint PDA) [6], and MHT (Multiple Hypothesis Tracking) [7–9] have drawn attention as target tracking methods in an environment in which false signals from objects other than the target such as clutter exist [10, 11]. In target tracking in such an environment, just the region is considered for each target in which the target is expected to exist at the next sampling time [12]. This region is called the gate. The observation data within the gate are used for tracking. Various gate shapes are conceivable, such as a rectangle, circle, and ellipse. However, it is not known which shape of gate is optimum. If the gate is enlarged, many observation vectors from clutter or objects other than the target fall within the gate, resulting in some difficulties in target tracking. On the other hand, if the gate is made smaller, there is a danger that the observation data from the target to be tracked may not fall within the gate. It is more desirable that the position of the observation vector detected from the target be closer to the center of the gate compared with location of the false signals in the gate [13]. A method of determining the in-gate probability has been proposed in [10]. In this paper, asymmetrical gaussian distribution is introduced. Cross-surface of asymmetrical gaussian
Tuberculosis and Traditional Medicine: Fighting the Oldest Infectious Disease Using the Oldest Source of Medicines
Farzad Kobarfard
Iranian Journal of Pharmaceutical Research , 2004,
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