• 한국건설관리학회논문집
• /
• 제16권5호
• /
• pp.65-76
• /
• 2015

해외 플랜트 사업에서의 고부가가치를 창출하기 위해서는 기획 타당성조사, 프로젝트종합관리, FEED 및 기본설계 등 분야의 기술경쟁력 강화가 시급하다. 특히, FEED 업무는 프로젝트 전체에 대한 영향력이 절대적이고, 또한 기자재 및 패키지 산업의 경쟁력 강화에도 결정적 역할을 한다. 그럼에도 불구하고, FEED 관련 선행연구들은 설계업무 중심의 프로세스 및 성과물을 위한 연구가 대부분이며, 프로젝트 전체에 영향을 미치는 관리적 관점의 FEED 업무에 대한 연구는 미흡한 실정이다. 따라서 본 연구에서는 발전플랜트 중 화력발전소를 대상으로 사업관리 관점의 FEED 업무 프로세스 구조 및 항목을 제안하였다. 도출된 FEED 관리 업무는 3개의 레벨로 나누어진 계층적 구조를 가지고 있으며, 업무 항목에 대한 전문가 검증을 실시하였다. 또한 FEED 관리 업무에 대한 평가지표별 평가를 통해 결과를 분석한 결과 설계 중심의 업무들은 역량이 높지만 중요도가 높은 관리적 관점의 FEED 업무들의 역량은 부족한 것으로 나타났다. 그러므로 본 연구에서 제안한 FEED 관리업무 프로세스 구조는 FEED 역량 강화를 위한 가이드라인이 될 것이라 기대한다.

• 한국통신학회:학술대회논문집
• /
• 한국통신학회 1987년도 춘계학술발표회 논문집
• /
• pp.176-179
• /
• 1987

• 대한기계학회논문집A
• /
• 제26권1호
• /
• pp.15-22
• /
• 2002

This paper introduces a compensating system for machining error, which is resulted from chucking with separated jaws. In machining the chucked cylindrical workpiece, the deterioration of machining accuracy, such as out-of-roundness is inevitable due to the variation of the radial compliance of the chuck workpiece system which is caused by the position of jaws with respect to the direction of the applied force. To compensate the chucking compliance induced error, firstly roundness profile of workpiece due to chucking compliance after machining needs to be predicted. Then using this predicted profile, the compensated tool feed trajectory can be generated. And by synchronizing the cutting tool feed system with workpiece rotation, the chucking compliance induced error can be compensated. To satisfy the condition that the cutting tool feed system must provide high speed and high position accuracy, brushless linear DC motor is used. In this study, firstly through the force-deflection experiment in workpiece chucked lathe, the variation of radial compliance of chuck workpiece system is obtained. Secondly using the mathematical equation and cutting experiment result, the predicted profile of workpiece and its compensation tool trajectory are generated. Thirdly the configuration of compensation system using linear motor is introduced, and to improve the system performance, PID controller is designed. Finally the tracking performance of system is examined by experiment. Through the real cutting experiment, roundness is significantly improved.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 1999년도 추계학술대회 논문집
• /
• pp.267-272
• /
• 1999

The auxiliary power supply system fur passenger service of railway car has been developed from MA(Motor-Alternator) to CVCF Inverter (Static Inverter). Generally, a customer wants to apply tile new control method and device for auxiliary power supply of railcar However, if the auxiliary power supply is supplied to extended existing line, the maintenance cost of the old system is less expensive than new developed system, so, the customer specifies that the auxiliary power supply has compatibility with existing one completely. At that time, the hardware is nearly same as existing system except small changes of accessories for better performance. This paper describes the flicker control using feed-forward method of auxiliary power supply system for new 50 electric railcars, which are delivered to Korean National Railroad (KNR) Kwa-chon Line. The existing power supply system has damping resistor box to stabilize the DC input (1.5 ㎸). At this time, for better system efficiency the new system has not include resistor box but new control method including feed-forward control is applied. This control algorithm realizes the better stabilization of input power compared to the result of the existing system, which includes resistor box

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2007년도 제38회 하계학술대회
• /
• pp.1603-1604
• /
• 2007

The load of power plants changes every from time to time according to which steam flow of boiler changes. the feed water control is very important for the power plant to be operated in its stability conditions. In case of circulation type boiler, the instability of feed water control leads to instability of drum level control. The higher level of drum water can induce bad quality steam to go into turbine which means the possibility of damage. The lower level of drum water can induce the tubes of boiler water wall to be overheated. In case of once through type boiler, the instability of feed water control leads to bad cooling of superheaters. The less the feed water flow is, the more heated the superheater is. It is necessary for the turbine driving feed water pump to be controlled for the optimal feed water flow in the large capacity power plant. The speed of turbine is controled for the feed water flow. By the way, the optimal control of steam valve is necessary for the speed control of turbine. Therefore, the various kinds of the steam valve structures are introduced in this paper

• 상하수도학회지
• /
• 제29권1호
• /
• pp.89-96
• /
• 2015

Smart water grid is a water network with communication to save water and energy using various water resources. In smart water grid, water product from the various sources can be blended to be supplied to end-users. The product water blending was reported by literatures while feed water blending has been rarely reported so far. In this work, a commercial reverse osmosis (RO) system design software provided by a membrane manufacturer was used to elucidate the effect of feed water blending on the performance of seawater reverse osmosis (SWRO) plant. Fresh water from exisiting water resource was assumed to be blended to seawater to decrease salt concentration of the RO feed water. The feed water blending can simplify the RO system from double to single pass and decrease seawater intake amount, the unit prices of the RO system components including high pressure pump, and operation risk. Due to the increase in RO plant capacity with the feed water blending, however, the RO membrane area and total power consumption increase at higher water blending rates. Therefore, a specific benefit-cost analysis should be carried out to apply the feed water blending to SWRO plants.

• 한국자동차공학회논문집
• /
• 제19권4호
• /
• pp.91-98
• /
• 2011

Minimizing the cylinder wear and the consumption rate of cylinder oil in a large two-stroke diesel engine is of great economic importance. A motor-driven cylinder lubricator for Sulzer RT-flex large two-stroke diesel engines developed by authors is in need of mounting a quill system to lubricate cylinder parts for smoother operation. In order to apply the common-rail lubricating system to the developed cylinder lubricator as the second research stage, the quill system with a progressively quantitative distributor is improved in the electronically controlled quill system with an accumulating distributor. In this study, the effects of lubricator motor speed, plunger stroke and cylinder back pressure on oil feed rate, maximum discharge and delivery pressures are experimentally investigated by using the electronically controlled quill system with an accumulating distributor in the developed cylinder lubricator. It is found that the oil feed rate of the electronically controlled quill system with an accumulating distributor is larger than that of the quill system with a progressively quantitative distributor because of the increase of delivery speed and volume by changing the location of accumulator in the same experimental condition.

• 한국태양에너지학회 논문집
• /
• 제34권5호
• /
• pp.23-31
• /
• 2014

This study was accomplished to get the foundation design data of VMD(Vacuum Membrane Distillation) system for Solar Thermal VMD plant. VMD experiment was designed to evaluate thermal performance of VMD using PVDF(polyvinylidene fluoride) hollow fiber hydrophobic membranes. The total membrane surface area in a VMD module is $5.3m^2$. Experimental equipments to evaluate VMD system consists of various parts such as VMD module, heat exchanger, heater, storage tank, pump, flow meter, micro filter. The experimental conditions to evaluate VMD module were salt concentration, temperature, flow rate of feed sea water. Salt concentration of feed water were used by aqueous NaCl solutions of 25g/l, 35g/l and 45g/l concentration. As a result, increase in permeate flux of VMD module is due to the increasing feed water temperature and feed water flow rate. Also, decrease in permeate flux of VMD module is due to increasing salinity of feed water. VMD module required about 590 kWh/day of heating energy to produce $1m^3/day$ of fresh water.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 2002년도 춘계학술대회 논문집
• /
• pp.346-351
• /
• 2002

Several algorithm applied to single axis feed system with linear motor has been extensively reviewed in order to check the possible applicability to two axis system Among several factors considered, overshoot of the response was the most important one in minimizing position tracking error. Balance between overshoot and settling time has be adjusted to guarantee to best tracking performance.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 2001년도 춘계학술대회 논문집(한국공작기계학회)
• /
• pp.413-417
• /
• 2001

High speed linear motor feed system has been simulated using neural network technique. Due to the limited resources, control gain tuning has been the most troublesome part in controller design. Regardless of the system structure, conventional control gain could be adjusted minimizing the resulting error using the proposed method. Slight performance deterioration was observed at the small value of training epoch.