• Title, Summary, Keyword: unit load system

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A Study on the Digital Unit Development for Turbine Load Set Control (Turbine Load Set 조정을 위한 Digital Unit 개발)

  • Moon Yong-Seon;Jeong Ho-Jin;Kang Sung-Ryul;Choi Hyeong-Yoon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.9 no.3
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    • pp.498-503
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    • 2005
  • As important device that decide output load in superannuated thermoelectric power plant which do Turbine Load Set Motor device. This generation of electric power system operated Set Up Range Motor according to Set Up value that operator manufactures by hand circumvolve, and generation of electric power output load derision is consisted by internal action including Motor Therefore, in this research passively output load operated Turbine Motor Drive equipment that can have existing Turbine Load Set Motor Performance developing Digital Drive Unit device design. Also control algorithm implementation and existing Turbine Load Set Motor Drive and connection possibility through designed controlling system to connect basis function that decide development output load with Digital Drive Unit that designed also with existing Motor Drive Unit and can be operated.

Optimal Redundant Units and Load in Parallel Systems (병렬 시스템에서의 최적 중복부품수와 최적 부하수준)

  • 윤원영;김귀래
    • Journal of the Korean Operations Research and Management Science Society
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    • v.23 no.1
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    • pp.97-107
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    • 1998
  • This paper is concerned with a parallel system that sustains a time-independent load and consists of n components with exponential lifetimes. It is assumed that the total load is shared by the working components and the failures of components increase higher failure rates in the surviving components according to the relationship between the load and the fialure rates. The power rule model among several load-failure rate relationships is considered. We consider the system efficiency meausre as the expected profit earned by the system per unit time. The high load causes high gain but it also occurs frequent system failures. The expected profit per unit time is used as criterion to evaluate the system efficiency. The goal of system engineer is to determine the optimal load and redundant units maximizing the expected profit per unit time. First, the system reliability function is obtained and the optimization problem of the load-sharing parallel system is considered. Given the redundant units, the existence of the optimal load can be proved analytically and given the load, the optimal redundant units can be solved also analytically. The optimal load and redundant units are obtained simultaneously by numerical computation. Some numerical examples are studied.

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A Study on Driving Motor Performance Comparison for Load Efficiency Improvement of a Bicycle Locker System (자전거 거치대 잠금장치의 부하시 효율개선을 위한 구동모터성능비교에 관한 연구)

  • Han, Ki-Soo;Won, Sung-Hong
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.62 no.4
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    • pp.175-180
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    • 2013
  • This paper presents the design and implementation of a Bicycle Locker System. Generally DC motor has been used to control a Bicycle Locker System, but DC motor system requires frequent maintenances and its power efficiency is comparatively poor especially under heavy load conditions. In order to improve this difficulties, this paper adopts BLDC motor for a Bicycle Locker System and its motor controller is developed. The performances of locker units are compared between DC motor unit and BLDC motor unit. The motor power consumptions between two motors are discussed. Test results verify that power efficiency of the suggested BLDC drive unit is considerably improved compared to the DC drive unit with load condition.

A Situations and Improvements on the Rail Freight System (철도화물수송체계의 현황과 개선방안)

  • 이용상
    • Journal of the Korean Society for Railway
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    • v.7 no.1
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    • pp.37-48
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    • 2004
  • In this paper, I explain the situations and problems which are focused on the rail freight system. We have a many problems, which have been showed the long freight logistics time, and inadequate fare system. And rail freight system does not have a efficient marketing system, and unit load system. Therefore rail freight has been decreased modal share, which is estimated from 9.65% in 1995 to 6.25% in 2001(ton base). Recently, EU nations and America rail freight system reveals a good outcome, which keeps the balance in the black. The main factors which go into the black, is the enlargement the investment in rail freight and efficient management focusing on the unit load system, fare system, and personnel management. I suggest the several improvement ways, which will be helpful to advance the rail freight system. Fistly, I suggest the speed up the freight rail and efficient fare system. Secondly, I propose the unit load system and the regulation the truck focusing on curtailment of the social cost. Lastly, I make an overture of establishment the comprehensive logistics system.

Unit-load Method for the Estimation of Non-point Pollution Loads by Subcategorizing the Land-use Category Reflected in the National Land Register Data : A Case Study of Kyeongan Watershed in South korea (경안천 유역 지적공부에 나타난 특정지목의 토지이용 특성 세분화를 통한 비점오염 부하량 산정 개선방안)

  • Lee, Bum-Yeon;Lee, Chang-Hee;Ha, Do;Lee, Su-Woong
    • Journal of Korean Society on Water Environment
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    • v.26 no.4
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    • pp.598-607
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    • 2010
  • One of constraints in the application of unit-load method to estimate non-point pollution loads in the total water pollutant load management system (TWPLMS) is the limited numbers of applicable unit-loads. Since only 7 unit-loads are currently available for total 28 land-use categories in the national land register data, each unit-loads inevitably have to represent several land-use categories regardless of their actual land coverage characteristics. As a way to minimize the problem, this study suggested a nested application of the available unit-loads based on the analysis of high resolution aerial images taken in the Kyeongan watershed. Statistical analysis of three selected land-use categories such as school, apartment complex, and golf course showed that there exit significant (95% confidence level) relationships between the registered land-uses and actual land coverages. The school and apartment complex currently considered as 100% ground have only 65% and 80% of ground characteristics, respectively. Golf course, which is considered as 100% pasture, has about 5% of ground area. This indicates that the unit-load method using in TWPLMS can give over estimated non-point pollutant loads for the school and apartment complex (19.8~54.4%) but under estimation for the golf course (80.9%).

Performance Analysis of Water-to-Air Heat Pump System under Water Temperature and Load Ratio (열원 및 부하조건에 따른 물-공기 히트펌프 시스템의 성능분석)

  • Cho, Yong;Lee, Dong Keun
    • 한국신재생에너지학회:학술대회논문집
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    • pp.194.2-194.2
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    • 2011
  • Heating and cooling performance has been analyzed for the water-source heat pump system using raw water from Daechung reservoir. During heating operation from March to May, water temperature is not good condition for a heat source due to the higher atmospheric temperature. Avearged heating load ratio is only 14.3%, and the averaged unit COP and system COP are estimated to be 2.46 and 2.15 respectively. The COP is affected considerably by the water temperature, and the unit COP is increased from 2.16 at $5^{\circ}C$ to 2.95 at $11^{\circ}C$. Cooling performance is analyzed with the measured data from June to August. During cooling operation, raw water has lower temperature by 4. $5^{\circ}C{\sim}4.7^{\circ}C$ than the atmosphere. The load ratio is 39.2%, and the averaged unit COP and system COP are estimated to be 7.25 and 6.13 respectively. The heating COP is affected by the load ratio rather than water temperature. The COP is increased for 20%~40% load ratio, while is decreased for 40%~60% load ratio. It is estimated that the compressor operation combination for 3 (two constant speed and one inverter) compressors is changed for the load ratio.

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A Research on Logistics System for Agro-Food (농식품 물류체계에 관한 연구)

  • Ha, Young-Sun
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.13 no.1
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    • pp.29-32
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    • 2007
  • In a comparison the Logistics system for Agro-food of Korea and the Logistic system of Europe and Japan, the more developed countries of Europe have better systems. This well-formed rationalization of Logistics on Agro-food, and perfectly-equipped packaging system measurements for Agro-food make 100% pallet freight possible. Also, this means that a unit load system has been achieved. In Japan, the Logistic system is mainly accomplished by auction. However, it has been rapidly changing into the same type as the developed countries these days. Logistic system in Korea is also mainly accomplished by auction under the influence of Japan. However it also has been rapidly changing in to the same type as the developed countries these days. In the future, Korea has to build up international competitiveness in the face of FTA(Free Trade Agreement) era. This can happen by having better-organized Agro-food Logistics system and unit load system which results in accurate packaging system measurements.

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A STUDY ON THE REACTIVE POWER COMPENSATION OF THREE PHASE UNBALANCED LOAD FOR VAR SYSTEM (VAR 시스템에 의한 3 상 불평형 부하의 무효전력 보상에 관한 연구)

  • Jung, Yon-Taek;Seo, Young-Soo;Kim, Young-Bong;Kim, Han-Soo;Lee, Bong-Joo
    • Proceedings of the KIEE Conference
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    • pp.531-534
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    • 1989
  • In this paper, the way that input voltage and input line current as a control variable is provided as one unit is projected. Till no, have denied with three phase balanced load. But, in that case, total power factor compensation is difficult, for to control each phase at unbalanced load. Therefor, in this paper suggest of the scheme that three phase unbalanced load is controlled by each phase and input total power factor is compensated unit input factor. therefore, in this paper suggest that three phase unbalanced load is controlled and the method in compensation of unit input factor to be attended by unbalanced load. Besides, the object of control is calculating quantity for input voltage and input line current for the point at issuse make to improve of control method at unbalanced load. As a result, control system of each phase could maintain as a unit input total power factor has been state diviation error of 2% with unbalanced load.

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Application of the Load Duration Curve (LDC) to Evaluate the Achievement Rate of Target Water Quality in the Han-River Watersheds (부하지속곡선(Load Duration Curve; LDC)을 이용한 한강수계 오염총량관리 목표수질 평가방법 적용 방안)

  • Kim, Eunkyoung;Ryu, Jichul;Kim, Hongtae;Kim, Yongseok;Shin, Dongseok
    • Journal of Korean Society on Water Environment
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    • v.31 no.6
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    • pp.732-738
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    • 2015
  • Water quality in four major river basin in Korea was managed with Total Maximum Daily Load (TMDL) System. The unit watershed in TMDL system has been evaluated with Target Water Quality (TWQ) assessment using average water quality, without considering its volume of water quantity. As results, although unit watershed are obtained its TWQ, its allocated loads were not satisfied and vice versa. To solve these problems, a number of TWQ assessments with using Load Duration Curve (LDC) have been studied at other watersheds. The purpose of this study was to evaluate achievement of TWQ with Flow Duration Curve (FDC) and Load Duration Curve(LDC) at 26 unit watersheds in Han river basin. The results showed that achievement rates in TWQ assessment with current method and with LDC were 50~56 % and 69~73%, respectively. Because of increasing about 20% of achievement rates with using LDC, the number of exceeded unit watershed at Han river Basin was decreased about 4~6 unit watersheds.

Development of Unit Commitment Methodology Considering Direct Load Control by 3-Dimensional Dynamic Programming (3차원 동적계획법에 의한 직접부하제어를 고려한 기동정지계획 방법론의 개발)

  • Lee, Buhm;Kim, Yong-Ha;Choi, Sang-Kyu;Kim, Hyeong-Jung
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.51 no.12
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    • pp.591-596
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    • 2002
  • This Paper Presents a new methodology for Direct Load Control(DLC) and Unit Commitment. To consider economical effect of DLC, we developed 3-Dimensional dynamic programming which can combine unit commitment and DLC. Traditional dynamic programming has 2-Dimensional which consist of state and stage, but newly developed dynamic programming has DLC state, U.C. state, and stage. As a result, economical DLC and unit commitment schedule of the power system is possible. This method is applied to the test system, and the usefulness of the method is verified.