Sharif Digital Repository

In this paper, the tardiness flow shop models with intermediate due date were considered. The flow shop models consist of a set of jobs each having a number of operations, while each operation is performed in a single machine. All the jobs are considered having the same unidirectional precedence order. In the tardiness flow shop models with intermediate due date, which we call the generalized tardiness flow shop models, there exist a due date associated with the completion of each operation, and we want to find a schedule which minimizes the total tardiness of the jobs. This is a more general version of tardiness flow shop in the sense that, by assigning a large value to each of the... 

In this paper, the scattering of anti-plane shear waves in an infinite matrix containing a multi-coated nanofiber/nanotube is studied. Based on the fact that the surface to volume ratio for nano-size objects increases, the usual classical theories which generally neglect the surface/interface effects fail to provide reasonable results. Therefore, to analyze the problem the wave-function expansion method is coupled with the surface/interface elasticity theory. In order to provide some quantitative results through consideration of several examples, the knowledge of the relevant surface and/or interface properties of the corresponding constituent materials are required. For this reason, part of... 

L-Ascorbate anion electro-oxidation on a silver electrode in hydroxide solution in the absence and presence of sodium polysulfide of concentrations from 1 × 10 -5 to 4.5 × 10 -4 mol/L was studied using cyclic voltammetry and electrochemical impedance spectroscopy. Both hydroxide and polysulfide ions inhibited L-ascorbate ion oxidation, with the poisoning effect of polysulfide ion being more pronounced in the potential range of -0.3 to -0.2 V/SCE. The time constants for L-ascorbate ion oxidation in the absence and presence of polysulfide were, 10 -3 to 1 × 10 -2 s and 1 × 10 -4 to 1 × 10 -2 s, respectively depending on the potential used for the impedance analysis. Based on the cyclic... 

Flow mediated dilation (FMD) measurement using ultrasound imaging (FMD-US) has been established as a standard method for assessing the endothelial function. Recently, a less skilled-operator demanding method has been proposed based on the photoplethysmogram (PPG) changes during reactive hyperemia. It was shown that the amplitude of the PPG pulse (FMD-PPG) changed in a quite similar manner to that of the artery diameter in the method of the FMD-US i.e. increases following releasing the cuff and then gradually returns to baseline. In this study PPG changes following reactive hyperaemia were modelled using time-varying passive electrical elements (R, L and C). The output of the electric analog... 

Analysis of the heart rate (HR) variation due to respiration, known as respiratory sinus arrhythmia (RSA), is a method to assess the autonomic nervous system (ANS) function. In this paper a physiologically-based mathematical model consisting of the cardiorespiratory system and ANS control has been used in order to study the cardiovascular response (mean arterial blood pressure and HR) to breathing with different respiration rates and tidal volumes. Simulation results show that RSA has its maximal amplitude at the respiration frequency of 0.12 Hz and that RSA amplitude varies linearly by tidal volume. These results are in agreement with real data from the literature. In addition, the... 

Cathodically deposited Ag 2Se, to form a 1-μm-thick film, characterized by energy dispersive X-ray analysis and scanning electron microscopy, showed high electro-catalytic activity for l-ascorbic acid oxidation in alkaline solution. The onset of the process was about 80 mV cathodic of that previously observed on Ag under the same conditions and far superior over glassy carbon and Pt. The values of the exchange current density, standard heterogeneous rate constant, and transfer coefficient of the reaction were 1. 65 × 10 -4 A cm -2, 4. 35 × 10 -7 cm s -1, and 0. 60, respectively. Diffusion coefficient of l-ascorbate di-anion was also measured and was around 7. 00 × 10 -6 cm 2 s -1  

Call admission control schemes are crucially Important concepts ID researches on cellular mobile networks. One of them is the new thinning scheme. In this study we define a confidence interval for threshold and the numerical results show the performance of the scheme in defined interval. Also we discuss the sensitivity of the scheme (in sample-based sensitivity method) at different thresholds. The results show the better performance in confidence thresholds and sensitivity of scheme into variations of thresholds  

Climate studies and effective environmental management require unbiased climate datasets. This study develops a new bias correction approach using a three-layer feedforward neural network to reduce the biases of climate variables (temperature and precipitation) over northern South America. Air and skin temperature, specific humidity, and net longwave and shortwave radiation are used as inputs to the network for bias correction of 6-hourly temperature. Inputs to the network for bias correction of monthly precipitation are precipitation at lag 0, 1, 2, and 3 months, and also the standard deviation of precipitation from 3 × 3 neighbors around the pixel of interest. The climate model data are... 

In this paper, we develop and analyze a novel performance metric, called interference efficiency (IE), that shows the number of transmitted bits per unit of interference energy imposed on the primary users (PUs) in an underlay cognitive radio network (CRN). Specifically, we develop a framework to maximize the IE of a CRN with multiple secondary users (SUs) while satisfying target constraints on the average interference power on PU receiver, total SUs transmit power and minimum ergodic rate for the SUs. In doing so, we formulate a multiobjective optimization problem (MOP), that aims to achieve the maximum ergodic sum rate of multiple SUs and the minimum average interference power on the... 

In this paper, we develop and analyze a novel performance metric, called interference efficiency, which shows the number of transmitted bits per unit of interference energy imposed on the primary users (PUs) in an underlay cognitive radio network (CRN). Specifically, we develop a framework to maximize the interference efficiency of a CRN with multiple secondary users (SUs) while satisfying target constraints on the average interference power, total transmit power, and minimum ergodic rate for the SUs. In doing so, we formulate a multiobjective optimization problem (MOP) that aims to maximize ergodic sum rate of SUs and to minimize average interference power on the primary receiver. We solve... 

Statistical bias correction methods are inferred relationships between inputs and outputs. The constructed functions are based on available observations, which are limited in time and space. This study investigates the ability of regression models (linear and nonlinear) to regionalize a domain by defining a minimum number of training pixels necessary to achieve a good level of bias correction performance. Linear regression is used to divide northern South America into five regions. To correct the biases of temperature and precipitation, an artificial neural network (ANN) model was trained with selected pixels within each region and then used to reproduce bias-corrected temperature and... 

Taxonomy learning is one of the major steps in ontology learning process. Manual construction of taxonomies is a time-consuming and cumbersome task. Recently many researchers have focused on automatic taxonomy learning, but still quality of generated taxonomies is not satisfactory. In this paper we have proposed a new compound similarity measure. This measure is based on both knowledge poor and knowledge rich approaches to find word similarity. We also used Neural Network model for combination of several similarity methods. We have compared our method with simple syntactic similarity measure. Our measure considerably improves the precision and recall of automatic generated taxonomies. ©... 

(Chemical Equation Presented) An efficient and simple route is presented to the synthesis of some iminothiazolidinone derivatives. α-Chloro amide derivatives undergo coupling reaction with isothiocyanate in the presence of a mild base, followed by nucleophilic substitution of chlorine by the sulfur atom of isothiocyanate  

In this paper, a mesh-less numerical approach is utilized to solve Euler's equation that is the governing equation of the irrotational flow of ideal fluids. A fractional step method of discritization is applied which consists to split each time step in two steps. This numerical method is based on moving-particle semi-implicit method (MPS) for simulating incompressible inviscid flows with free surfaces. The motion of each particle is calculated through interactions with neighboring particles covered with the kernel function. There are limitations for getting a stable solution by MPS method. In this paper, various kernel functions are considered and applied to improve the stability of MPS... 

Responseamplitudemitigationof theoffshorestructures like tensionlegplatform(TLP) is important since these structures are always exposed to environmental loads such as waves, andin thecaseofTLP, reduction in responseamplitudeofplatformcauses reduction in stress range in tendons; thiswould increase the fatigue life of tendons, and therefore, increases the structural safety. Also providing stable conditions for machinery and crew increases the efficiency and functionality of the platform. This article thus aims to investigate the possibility and effectiveness of applying tuned mass damper (TMD) as a passive structural control systemto suppress the surgemotion of TLP that is exposed to wave... 

C15H10ClN3O3S, orthorhombic, Pbca (no. 61), a = 11.981(2) Å, b = 14.890(4) Å, c = 17.239(4) Å, V = 3075.4 Å3, Z = 8, Rgt(F) = 0.053, wRref(F2) = 0.123, T = 120 K. © by Oldenbourg Wissenschaftsverlag  

In solution of the Euler equations in the steady state external flows, error or residual waves are blamed for decelerating the convergence. These waves may be damped by adding a bulk viscosity term to the momentum equations. We analyse effects of this term on the linearized differential equations, and study its explicit and implicit implementation in one and two space dimensions. Optimum values of the bulk viscosity damping (BVD) are discussed. After generalization to two space dimensions, its performance both alone and in combination with a soft wall boundary condition and residual smoothing in central differencing codes is reviewed. It is shown that BVD is complementary to them, and acts... 

C15H10ClN3O3S, orthorhombic, Pbca (no. 61), a = 11.981(2) Å, b = 14.890(4) Å, c = 17.239(4) Å, V = 3075.4 Å3, Z = 8, Rgt(F) = 0.053, wRref(F2) = 0.123, T = 120 K. © 2014, Oldenbourg Wissenschaftsverlag München. All rights reserved  

Electromagnetic scattering from thin resistive strips is formulated using an integral equation approach. Analytical expressions for the electric current density over wide and narrow strips are derived based on the physical optics and quasistatic approximation of the pertinent integral equations, respectively. The solutions are used to find closed form expressions for the echo width of the strip  

Electromagnetic scattering from thin resistive strips is formulated using an integral equation approach. The formulation is then specialized to strips of constant curvature and arbitrary size allowing the employment of the method of moments to solve the scattering problem