Volume 4 ~ Issue 11

An inventory model for deteriorating items with stock and price dependent demand is developed. Holding cost is considered as function of time. Shortages are not allowed. Numerical examples are provided to illustrate the model and sensitivity analysis is also carried out for parameters..

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Author Keywords:- Inventory model, Deterioration, Price dependent demand, Stock dependent demand, Time varying holding cost

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e-ISSN: 2319-183X, p-ISSN: 2319-1821 Source Type: Journal Original Language: English
Document Type: Article Number of pages: 12

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© Copyright 2014, All rights reserved.

Children with mental challenges, functioning significantly below average, are treated with different kinds of psychological therapies. Data is collected from 145 families with one child each, meeting given qualifying criteria, taking similar psychological therapies for past three months. Likert scale is used to find the response of each therapy. 145 cases include 62.07% (90/145) boys and 37.93% (55/145) girls. Multiple regression models are used to determine effectiveness of these therapies on basic skill /behavior /mental ability. It is concluded that head phone therapy is the most significant contributor for estimating basic skill (BS), Intellectual ability (IA) and Social and Psychological development (SPD). The given psychological therapies are proven effective in 99% of cases.

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Author Keywords:- ..

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e-ISSN: 2319-183X, p-ISSN: 2319-1821 Source Type: Journal Original Language: English
Document Type: Article Number of pages: 06

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© Copyright 2014, All rights reserved.

Several studies have investigated the potential of using FACTS Controllers' capability in damping inter-area oscillations. The uses of Thyristor Controlled Series Capacitor (TCSC) and Static Synchronous Series Compensator (SSSC) have been the subjects of several studies evaluating their respective effectiveness in enhancing power system dynamics. The recently proposed phase imbalanced series capacitive compensation concept has been shown to be effective in enhancing power system dynamics as it has the potential of damping power swing as well as sub synchronous resonance oscillations. In this project, the effectiveness of a "hybrid" series capacitive compensation scheme in damping power system oscillations is evaluated. A hybrid scheme is a series capacitive compensation scheme, where two phases are compensated by fixed series capacitor (C) and the third phase is compensated by a TCSC in series with a fixed capacitor (Cc). The effectiveness of the scheme in damping power system oscillations for various network conditions, namely different system faults and tie-line power flows is evaluated using the MATLAB simulation program.

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Author Keywords:- FACTS Controllers, phase imbalance, series compensation, thyristor controlled series capacitor

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e-ISSN: 2319-183X, p-ISSN: 2319-1821 Source Type: Journal Original Language: English
Document Type: Article Number of pages: 08

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© Copyright 2014, All rights reserved.

This paper describes the modeling, simulation and analyzes of custom power devices for compensating voltage sag and swell conditions in three phase systems. Faults occurring in power distribution systems or facilities in plants cause the voltage sag or swell. If a fault occurs, it can damage the power system or user's facility. Sensitivity to voltage sags and swells varies within different applications. For sensitive loads (PLC's, paper mills etc.), even voltage sags of short duration can cause serious problems in the entire system. Normally, a voltage interruption triggers a protection device, which causes shutdown of the entire system. In order to mitigate power interruptions, this paper proposes a scheme for voltage sag support based on a pulse width modulated autotransformer. The proposed scheme is able to quickly recognize the voltage sag or swell condition, and it can correct the voltage by either boosting the input voltage during voltage sag events or reducing the voltage during swell events.

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Author Keywords:- DSTATCOM, Voltage sag, swell, power quality, PSCAD, PWM

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e-ISSN: 2319-183X, p-ISSN: 2319-1821 Source Type: Journal Original Language: English
Document Type: Article Number of pages: 06

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© Copyright 2014, All rights reserved.

The problem of voltage sags and swells and its major impact on sensitive loads are well known. To solve this problem, custom power devices are used. One of those devices is the Dynamic Voltage Restorer (DVR), which is one of the most efficient and effective modern custom power devices used in power distribution networks. A new control algorithm for the DVR is proposed in this paper to regulate the load terminal voltage during sag, swell in the voltage at the point of common coupling (PCC). This new control algorithm is based on synchronous reference frame theory (SRF) along with PI controller is used for the generation of reference voltages for a dynamic voltage restorer (DVR). These voltages, when injected in series with a distribution feeder by a voltage source inverter (VSI) with PWM control, can regulate the voltage at the load terminals against any power quality problem in the source side. It first analyzes the power circuit of the system in order to come up with appropriate control limitations and control targets for the compensation voltage control through the DVR. The control of the DVR is implemented through derived reference load terminal voltages. The proposed control scheme is simple to design. Simulation results carried out by MATLAB with its Simulink and Sim Power System (SPS) toolboxes to verify the performance of the proposed method.

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Author Keywords:- Power Quality, DVR, voltage sags/swells, VSI, Synchronous Reference Frame Theory, MATLAB/SIMULINK.

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e-ISSN: 2319-183X, p-ISSN: 2319-1821 Source Type: Journal Original Language: English
Document Type: Article Number of pages: 06

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© Copyright 2014, All rights reserved.

The purpose of reactive power scheduling is to improve the voltage profile of the system. This objective is achieved by installing reactive power sources at appropriate locations in a large power network. Proper adjustment of these sources is of paramount importance in obtaining the desired goal. This paper presents a methodology for alleviation of over voltage and under voltage conditions in the day to day operation of power systems by minimizing the sum of the squares of the voltage deviations from preselected desired values. The above objective function is selected to meet the recent requirements of utilities that are paying increasing attention to the problem associated with the voltage profile in power system. To achieve the desired objective, the control variable selected are tap position of transformers, reactive power injection of VAR sources and generator excitations. The proposed algorithm is applied to IEEE 30-bus systems and the results are obtained satisfactory with the proposed approach.

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Author Keywords:-

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e-ISSN: 2319-183X, p-ISSN: 2319-1821 Source Type: Journal Original Language: English
Document Type: Article Number of pages: 10

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© Copyright 2014, All rights reserved.

it is proposed that open loop integrated circuit for motor drives with dual mode control for EV/HEV applications are taken and a reduction technique is proposed for reducing number of switches, when bi-directional batteries are connected to the circuit, which helps in reducing circuit complexity. A closed loop system and the circuit is operated in two modes i.e., Conversion Mode and Inversion Mode. By using controlling technique current ripple content is reduced and losses are minimized resulting in high efficiency and continuous conduction. MATLAB Simulation is used for boosted Output Voltage and Current ripples.

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Author Keywords:- Bi-directional batteries, Integrated circuit, Motor drives, Voltage sources, PI Controller

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e-ISSN: 2319-183X, p-ISSN: 2319-1821 Source Type: Journal Original Language: English
Document Type: Article Number of pages: 06

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© Copyright 2014, All rights reserved.

Power system plays important role for the generation of power from conventional sources, transmutation and distribution power at different consumer applications it will faces a so many problems. This can be overcome to implement the power is generated from the renewable energy sources like P.V Wind, Fuel cell, Micro Turbine etc will give signifying moment in near future. In this paper power generated by using fuel cell system because power is generated from P.V system under cloud& rain session it is impossible and power generation of wind energy system is also difficult under summer session is also difficult under these conductions interruption power occurs at consumer applications this can be overcome to in this paper power generated from fuel cell system. Fuel cells are known for their reliability, power quality, eco-friendly nature and fuel efficiency. Its promising technology and extremely significant in the near future. A voltage source inverter controller is developed for conversion of SOFC generation into ac grid system. The designed controller is also implemented to analyzed the output response of the developed fuel cell that can be used in distributed generation applications. The simulation results are presented based on MATLAB simulink.

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Author Keywords:- Fuel Cell power generation, micro grid, grid-tied mode, coordination control operations, PV system

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e-ISSN: 2319-183X, p-ISSN: 2319-1821 Source Type: Journal Original Language: English
Document Type: Article Number of pages: 08

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© Copyright 2014, All rights reserved.

This paper presents the design of a 20 MHzhysteresis-controlled CMOS buck converter using pseudo ramp techniques for ultra-low power applications. The proposed buck converter can improve the transient response using hysteresis-controlled and fixed-voltage band techniques. Using pseudo ramp technique, pseudo inductor current signal can be produced to reduce the output voltage ripple. At the same time, the sub-1- V structure leads to low power dissipation. Moreover, by adopting the inverter-based low-voltage error amplifier topology, the proposed buck converter becomes most suitable for the low-power applications.The prototype of buck converter has been designed with 180nm 2P3M CMOS technology. The operating frequency of proposed converter is 20 MHz, with an inductor of 8.5 μH and a capacitor of 330 nF. Experimental results show that the output voltage is 0.5 V, the load current is 27 mA.

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Author Keywords:- Buck converter, hysteresis-controlled techniques, CMOS, pseudo ramp signal generation.

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e-ISSN: 2319-183X, p-ISSN: 2319-1821 Source Type: Journal Original Language: English
Document Type: Article Number of pages: 08

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© Copyright 2014, All rights reserved.