• Title/Summary/Keyword: Quality Output

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An Economic Feasibility Study for Construction and Use of Korea Ocean Research Stations (종합해양과학기지 구축 및 활용의 경제성 분석)

  • Song, Sang-Hwa;Shin, Kwang-Sup;Kim, Jae-Gon;Jeong, Jin-Yong
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.38 no.1
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    • pp.52-64
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    • 2015
  • Korea ocean research stations manage the weather and environmental data collected from coastal and ocean areas to provide short-term and long-term ocean forecasts. The purpose of this paper is to analyze and quantify economic benefits of the ocean research stations with sensors to observe physical, chemical, and biological data. The construction and operation of an integrated ocean observation station is expected to reduce uncertainty about ocean and coastal areas and to improve the quality of ocean forecasts. The economic benefits are mainly come from improved search and rescue operations, ocean pollution management, yellow dust management, and improved productivity in ocean-related industries. In addition, an input-output analysis is performed to evaluate the economic impacts of ocean research stations nationwide. The analysis shows that the system can contribute to industries such as fishing, maritime and air cargo, medical and health care.

Evaluation of the Wind Power Penetration Limit and Wind Energy Penetration in the Mongolian Central Power System

  • Ulam-Orgil, Ch.;Lee, Hye-Won;Kang, Yong-Cheol
    • Journal of Electrical Engineering and Technology
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    • v.7 no.6
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    • pp.852-858
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    • 2012
  • This paper describes evaluation results of the wind power penetration limit (WPPL) and the wind energy penetration (WEP) in the Mongolian central power system (MCPS). A wind power plant (WPP) in a power system possesses an output power limit because the power system must maintain a balance between the generation and consumption of electricity at all times in order to achieve an adequate level of quality. The instantaneous penetration limit (IPL) of wind generation at a load is determined as the minimum of the three technical constraints: the minimum output, the ramp rate capability, and the spinning reserve of the conventional generating units. In this paper, a WPPL is defined as the maximum IPL divided by the peak load. A maximal variation rate (VR) of wind power is a major factor in determining the IPL, WPPL, and WEP. This paper analyzes the effects of the maximal VR of wind power on the WPPL, WEP, and capacity factor (CF) in the MCPS. The results indicate that a small VR can facilitate a large amount of wind energy while maintaining a high CF with increased wind power penetration.

Learning an Artificial Neural Network Using Dynamic Particle Swarm Optimization-Backpropagation: Empirical Evaluation and Comparison

  • Devi, Swagatika;Jagadev, Alok Kumar;Patnaik, Srikanta
    • Journal of information and communication convergence engineering
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    • v.13 no.2
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    • pp.123-131
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    • 2015
  • Training neural networks is a complex task with great importance in the field of supervised learning. In the training process, a set of input-output patterns is repeated to an artificial neural network (ANN). From those patterns weights of all the interconnections between neurons are adjusted until the specified input yields the desired output. In this paper, a new hybrid algorithm is proposed for global optimization of connection weights in an ANN. Dynamic swarms are shown to converge rapidly during the initial stages of a global search, but around the global optimum, the search process becomes very slow. In contrast, the gradient descent method can achieve faster convergence speed around the global optimum, and at the same time, the convergence accuracy can be relatively high. Therefore, the proposed hybrid algorithm combines the dynamic particle swarm optimization (DPSO) algorithm with the backpropagation (BP) algorithm, also referred to as the DPSO-BP algorithm, to train the weights of an ANN. In this paper, we intend to show the superiority (time performance and quality of solution) of the proposed hybrid algorithm (DPSO-BP) over other more standard algorithms in neural network training. The algorithms are compared using two different datasets, and the results are simulated.

Integrated Operation of Power Conversion Module for DC Distribution System (직류 배전 시스템을 위한 전력 변환 모듈의 통합 운전)

  • Lee, Hee-Jun;Shin, Soo-Choel;Hong, Suk-Jin;Won, Chung-Yuen
    • The Transactions of the Korean Institute of Power Electronics
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    • v.19 no.3
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    • pp.240-248
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    • 2014
  • It is DC power that Output of renewable energy being recently developed and researched. Also, demand of DC power will expect to proliferate due to increase of digital load. Thus, DC distribution system providing high quality of power and reliability has emerged as a new distribution system. If the conventional distribution systems are substituted by proposed DC distribution system, the output of renewable energy can be connected with distribution systems under minimum power conversion. Therefore, in the event of connection with DC load, it can construct an efficient distribution system. In this paper, the integrated parallel operation of power conversion module for DC distribution system is proposed. Also, this paper proposed modularization of power conversion devices for DC distribution system and power control for parallel operation of large capacity system. DC distribution system consists of three power conversion modules such as AC/DC power conversion module 2 set, ESS module 1 set. DC distribution system controls suitable operation depending on the status of the DC power distribution system and load. Integrated operation of these systems is verified by simulation and experiment results.

Two-Channel Noise Reduction Using Beamforming and DOA-Based Masking (빔포밍 및 DOA 기반의 마스킹을 이용한 2채널 잡음제거)

  • Kim, Youngil;Jeong, Sangbae
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.17 no.1
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    • pp.32-40
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    • 2013
  • In this paper, we propose a multi-channel speech enhancement algorithm using beamforming and direction-of-arrival (DOA)-based masking. The proposed algorithm enhances noisy speech basically by the linearly constrained minimum variance (LCMV) algorithm and then a mel-scale Wiener filter designed using DOA-based masking is applied to remove still remaining noises. To improve the performance, we optimize the learning rate of the adaptive filters in LCMV and the DOA threshold to detect target speech spectrum. As performance indices, the perceptual evaluation of speech quality (PESQ) score and output SNRs are measured. Experimantal results show that the proposed algorithm outperforms the conventional LCMV beamformer by 0.09 in PESQ score and 5.75 dB in output SNR, respectively.

A Double-Hybrid Spread-Spectrum Technique for EMI Mitigation in DC-DC Switching Regulators

  • Dousoky, Gamal M.;Shoyama, Masahito;Ninomiya, Tamotsu
    • Journal of Power Electronics
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    • v.10 no.4
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    • pp.342-350
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    • 2010
  • Randomizing the switching frequency (RSF) to reduce the electromagnetic interference (EMI) of switching power converters is a well-known technique that has been previously discussed. The randomized pulse position (RPP) technique, in which the switching frequency is kept fixed while the pulse position (the delay from the starting of the switching cycle to the turn-on instant within the cycle) is randomized, has been previously addressed in the literature for the same purpose. This paper presents a double-hybrid technique (DHB) for EMI reduction in dc-dc switching regulators. The proposed technique employed both the RSF and the RPP techniques. To effectively spread the conducted-noise frequency spectrum and at the same time attain a satisfactory output voltage quality, two parameters (switching frequency and pulse position) were randomized, and a third parameter (the duty ratio) was controlled by a digital compensator. Implementation was achieved using field programmable gate array (FPGA) technology, which is increasingly being adopted in industrial electronic applications. To evaluate the contribution of the proposed DHB technique, investigations were carried out for each basic PWM, RPP, RSF, and DHB technique. Then a comparison was made of the performances achieved. The experimentally investigated features include the effect of each technique on the common-mode, differential-mode, and total conducted-noise characteristics, and their influence on the converter’s output ripple voltage.

Application of a C-Type Filter Based LCFL Output Filter to Shunt Active Power Filters

  • Liu, Cong;Dai, Ke;Duan, Kewei;Kang, Yong
    • Journal of Power Electronics
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    • v.13 no.6
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    • pp.1058-1069
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    • 2013
  • This paper proposes and designs a new output filter called an LCFL filter for application to three phase three wire shunt active power filters (SAPF). This LCFL filter is derived from a traditional LCL filter by replacing its capacitor with a C-type filter, and then constructing an L-C-type Filter-L (LCFL) topology. The LCFL filter can provide better switching ripple attenuation capability than traditional passive damped LCL filters. The LC branch series resonant frequency of the LCFL filter is set at the switching frequency, which can bypass most of the switching harmonic current generated by a SAPF converter. As a result, the power losses in the damping resistor of the LCFL filter can be reduced when compared to traditional passive damped LCL filters. The principle and parameter design of the LCFL filter are presented in this paper, as well as a comparison to traditional passive damped LCL filters. Simulation and experimental results are presented to validate the theoretical analyses and effectiveness of the LCFL filter.

Current Harmonics Rejection and Improvement of Inverter-Side Current Control for the LCL Filters in Grid-Connected Applications

  • Xu, Jinming;Xie, Shaojun;Zhang, Binfeng
    • Journal of Power Electronics
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    • v.17 no.6
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    • pp.1672-1682
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    • 2017
  • For grid-connected LCL-filtered inverters, the inverter-side current can be used as the control object with one current sensor for both LCL resonance damping and over-current protection, while the grid-voltage feedforward or harmonic resonant compensator is used for suppressing low-order grid current harmonics. However, it was found that the grid current harmonics were high and often beyond the standard limitations with this control. The limitations of the inverter-side current control in suppressing low-order grid current harmonics are analyzed through inverter output impedance modeling. No matter which compensator is used, the maximum magnitudes of the inverter output impedance at lower frequencies are closely related to the LCL parameters and are decreased by increasing the control delay. Then, to improve the grid current quality without complicating the control or design, this study proposes designing the filter capacitance considering the current harmonic constraint and using a PWM mode with a short control delay. Test results have confirmed the limitation and verified the performance of the improved approaches.

Design and Implementation of Multi-monitoring System for Motor Pump (모터 펌프를 위한 멀티-모니터링 시스템 설계 및 구현)

  • Kim, Tae Hyun;Yang, Oh
    • Journal of the Semiconductor & Display Technology
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    • v.18 no.4
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    • pp.81-86
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    • 2019
  • According to the needs of many users, motor pumps have been steadily developed and widely used in many industries where fluids are used. Motor pumps are used in a variety of environments, degrading quality and performance. It is becoming important to monitor the condition of motor pumps in order to maintain system performance and increase efficiency. This paper presents the method for effectively monitoring the condition of motor pumps. The designed MMI controller receives the collected data through data logging and output and controls the motor pump with touch screen. Implementing a Wi-Fi monitoring system and SCADA monitoring system based on Ethernet and RS485, user can monitor even if the user is far from the MMI controller without time and space limitation. In addition, by implementing a voice output system, the user can immediately recognize the situation through the sound. Therefore, through the proposed method, multi-monitoring system solves the cause of breakdowns and degradation of motor-pump and gives the possibility of commercialization by providing the convenience of maintenance to users.

A Design of Small Size Sensor Data Acquisition and Transmission System (소형 센서 데이터 수집 및 전송 시스템 설계)

  • Lim, Joong-Soo
    • Journal of Convergence for Information Technology
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    • v.9 no.1
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    • pp.136-141
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    • 2019
  • In this paper, we describe the design of a small size data acquisition system with STM32 processor based on Cortex-M4. The system is used for the sensor devices to collect raw data on production lines at factory and send them to the server computer in real time. Also the system is designed to easily acquisite various kinds of data collected from various sensors with the digital signal input unit, the analog signal input unit, the digital signal output unit and the analog signal output unit This small data acquisition system will contribute to the improvement of the quality of precision products in the industrial field by collecting various data in real time and transmitting data at high speed.