Sharif Digital Repository

Increasing redundant paths in transmission grids has always been thought to be a tool to enhance service reliability. However, network equations by intertwining power flows through redundant paths impose more limits on systems with more redundancy. Accordingly, autonomous removing of a few lines may relief capacity limit violations in some contingency events thereby enhancing service reliability. This paper aims to study impacts of manual removing of transmission lines on composite system reliability. For doing so, the existing model is extended to consider optimal transmission switching (OTS) as a remedial action. The model minimizes total damage cost imposed by load curtailments. The... 

Increasing redundant paths in transmission grids has always been thought to be a tool to enhance service reliability. However, network equations by intertwining power flows through redundant paths impose more limits on systems with more redundancy. Accordingly, autonomous removing of a few lines may relief capacity limit violations in some contingency events thereby enhancing service reliability. This paper aims to study impacts of manual removing of transmission lines on composite system reliability. For doing so, the existing model is extended to consider optimal transmission switching (OTS) as a remedial action. The model minimizes total damage cost imposed by load curtailments. The... 

Ultrasonic waves have been extensively used in many industrial applications including clean devices, pipes and vessels. A clear extension of this usage is the removal of wellbore contaminants by exposing it to high-power ultrasonic waves. In this paper, a mathematical model for ultrasonic propagation through the porous medium around the wellbore is presented. The equations of wave propagation are written in a cylindrical coordinate according to Biot theory and the induced stress in the rock are calculated at each point using finite difference approach Comparison of imposed local stresses with adhesion forces between scales and rock, the properties of ultrasonic transducer, such as frequency... 

The purpose of this study is providing a framework for the evaluation of process and content of development programs and evaluating the fourth and fifth law development program of Iran. Policy evaluation is one the most important measures in the policy cycle and is implemented with the purpose of learning from the results of stage. Given the wide dimensions of policy making, achieving a model for evaluating policy is faced with many complexities. In this study with reviewing previous experiences in the field of policy evaluation, an integrated model for evaluating policy, is presented from two main aspects of the process and the content and then with using this model, the Fourth Program and... 

The HIGHT algorithm is a 64-bit block cipher with 128-bit key length, at CHES'06 as a lightweight cryptographic algorithm. In this paper, a new related-key impossible differential attack on the full-round algorithm is introduced. Our cryptanalysis requires time complexity of 2127.276 HIGHT evaluations which is slightly faster than exhaustive search attack. This is the first related-key impossible differential cryptanalysis on the full-round HIGHT block cipher. Copyright  

We perform large-scale quantum Monte Carlo simulations of SLAC fermions on a two-dimensional square lattice at half filling with a single Dirac cone with N=2 spinor components and repulsive on-site interactions. Despite the presence of a sign problem, we accurately identify the critical interaction strength Uc=7.28±0.02 in units of the hopping amplitude, for a continuous quantum phase transition between a paramagnetic Dirac semimetal and a ferromagnetic insulator. Using finite-size scaling, we extract the critical exponents for the corresponding N=2 chiral Ising Gross-Neveu universality class: the inverse correlation length exponent ν-1=1.19±0.03, the order parameter anomalous dimension... 

Scattered and little research in the field of Persian speech synthesis systems has been performed during the last ten years. Comprehensive framework that properly implements and adapts statistical speech synthesis methods for Persian has not been conducted yet. In this paper, recent statistical parametric speech synthesis methods including CLUSTERGEN, traditional HMM-based speech synthesis and its STRAIGHT version, are implemented and adapted for Persian language. CCR test is carried out to compare these methods with each other and with unit selection method. Listeners Score samples based on CMOS. The methods were ranked by averaging the CCR scores. The results show that STRAIGHT-based... 

This paper proposes the use of a new binary decision tree, which we call a soft decision tree, to improve generalization performance compared to the conventional ‘hard’ decision tree method that is used to cluster context-dependent model parameters in statistical parametric speech synthesis. We apply the method to improve the modeling of fundamental frequency, which is an important factor in synthesizing natural-sounding high-quality speech. Conventionally, hard decision tree-clustered hidden Markov models (HMMs) are used, in which each model parameter is assigned to a single leaf node. However, this ‘divide-and-conquer’ approach leads to data sparsity, with the consequence that it suffers... 

Speech synthesis systems provided for the Persian language so far need various large-scale speech corpora to synthesize several target speakers' voice. Accordingly, synthesizing speech with a small amount of data seems to be essential in Persian. Taking advantage of a speaker adaptation in the speech synthesis systems makes it possible to generate speech with remarkable quality when the data of the speaker are limited. Here we conducted this method for the first time in Persian. This paper describes speaker adaptation based on Hidden Markov Models (HMMs) in Persian speech synthesis system for FARsi Speech DATabase (FARSDAT). In this regard, we prepared the whole FARSDAT, then for... 

This paper contains analysis and simulation of recent dynamic models, describing human emotion. The pharmacological discussions lead to a new model of drug taking, which also have a better performance for description of psychological and psychiatric phenomena. Studying the effects of the order of fractional model, obtains an advantage of the fractional order model over the integer order one  

We study the problem of finding a target t from a start point s in street environments with the cooperation of two robots which have a minimal sensing capability; that is, robots do not know any information about the workspace including information on distances, edges, coordinates, angles etc. They just can detect the discontinuities in the visibility region of their location. The robots can detect target point t as soon as it enters their visibility region and have communication peripherals to send messages to each other. Our aim is to minimize the length of the path passed by the robots. We propose an online algorithm for robots such that they move in the workspace and find the target.... 

Ag and Ni are immiscible, mainly due to their large lattice mismatch. This paper reports on their nanoscale formation of solid solution at room temperature by simple reduction reactions which lead to the amorphous Ag-Ni alloy nanoparticles (ANPs) with mono-disperse distribution. Microscopic and spectroscopic studies confirmed dependence of the alloy composition on size of nanoparticles. In the presence of different ligands such as sodium citrate, polyvinyl alcohol and potassium carbonate a mixture of silver oxide and Ag-Ni ANPs was achieved. Stoichiometry of the Ag-Ni ANPs was also found to be strongly dependent on ligands of the reduction reaction and further study shows without any ligand... 

Using the Markovian method, we study the stochastic nature of electrical discharge current fluctuations in the Helium plasma. Sinusoidal trends are extracted from the data set by the Fourier-Detrended Fluctuation analysis and consequently cleaned data is retrieved. We determine the Markov time scale of the detrended data set by using likelihood analysis. We also estimate the Kramers-Moyal's coefficients of the discharge current fluctuations and derive the corresponding Fokker-Planck equation. In addition, the obtained Langevin equation enables us to reconstruct discharge time series with similar statistical properties compared with the observed in the experiment. We also provide an exact... 

The clarification of rough non-alcoholic beer (RNAB) and diluted malt extract (DME) was investigated in a pilot plant consisting of a tubular ceramic membrane with nominal pore diameter of 0.45μm. The results of the primary experiments show that the concentration of suspended particles in the RNAB (∼0.05kg/m3) and DME (∼0.2kg/m3) correlates proportionally to turbidity (in NTU) with the factor of 4.45×10-4 (kgm-3NTU-1). During cross-flow microfiltration (CFMF), flux declined drastically with time due to fouling mechanisms and propensity. According to the characterizing curve of log(d2t/dV2) versus log(dt/dV), fouling is initiated by penetration of aggregates through the membrane surface,... 

Poly (vinyl alcohol)/graphene oxide (PVA/GO) gamma irradiated nanocomposite films and hydrogels were prepared. In composite films, GO was initially irradiated by gamma ray in order to improve interactions between GO and PVA. The film containing 1 wt-% GO was very strong where tensile modulus and tensile yield strength were 45 and 115% higher than those of pure PVA. In the second set of experiments PVA/GO hydrogels were made by irradiating PVA/GO suspensions by gamma ray at various doses. It was an interesting finding that GO increased the gel portion of hydrogels through contribution of H-bonds between PVA and GO. The hydrogels prepared at 20 kGy had remarkable water swelling ratio that... 

We use multifractal detrended fluctuation analysis (MF-DFA) to study the electrical discharge current fluctuations in plasma and show that it has multifractal properties and behaves as a weak anti-correlated process. Comparison of the MF-DFA results for the original series with those for the shuffled and surrogate series shows that correlation of the fluctuations is responsible for the multifractal nature of the electrical discharge current  

Automatic detection of prosodic events in speech such as detecting the boundaries of Accentual Phrases (APs) and Intonational Phrases (IPs) has been an attractive subject in recent years for speech technologists and linguists. Prosodic events are important for spoken language applications such as speech recognition and translation. Also in order to generate natural speech in text to speech synthesizers, the corpus should be tagged with prosodic events. In this paper, we introduce and implement a prosody recognition system that could automatically label prosodic events and their boundaries at the syllable level in Persian language using a Multi-Space Probability Distribution Hidden Markov... 

The main purpose of this paper is to use variational calculus and Pontryagin's minimum principle to propose a solution scheme for time optimal control problem stated on the fractional systems defined in the sense of Caputo. After deriving the necessary optimality conditions, a novel numerical solution is used to solve the problem. Afterwards, a simple case study shows the effectiveness of the proposed method. © 2017  

The main point of this paper is to present a time domain strategy for drug dosage to treat psychiatric disorders. A time domain model of emotion is obtained from an extension of a recently developed fractional nonlinear dynamic model of happiness. First, the Fractional Optimal Control law for incommensurate multi state systems is obtained. It will be then applied as an optimal drug administration procedure in the line of psychiatric disorders treatment. Results of this paper show that optimal control scheme is a proper approach to face the difficulties of analysis and control the incommensurate systems. It can be also clearly seen from the simulation results that this approach is very...