• 전기학회논문지
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• 제64권2호
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• pp.331-337
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• 2015

The power flow analysis of electrified railway is required complicated calculation, because of variable load. Train runs trough rail supplied by electric power therefore, the load value in electrified railway system fluctuates along time. The power flow algorithm in electrified railway system is different from general power system, and the power flow simulation is peformed by the particular simulation software. Powerail is simulation software for analysis of traction power supply system developed by KRRI, in 2008. This consists of load forecasting module, including TPS and time scheduling, and power flow module. This software was verified by measured current under normal feeding condition, however, has not been verified by voltage on the condition of extended feeding. This paper presents the verification of PowerRail based on voltage drop under extended feeding condition. This is performed by comparing simulation result with field test. Field test and simulation is done in commercial railway line.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.1315-1318
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• 2004

Each feeding power is transformed 3 phases of KEPCO through SCOTT transformer and operate a electric train in AC Feeding system of electric railway. Nowaday a power conversion system, installed inside the train, generate a harmonics and has a effect on a power quality and it is necessary to install a countermeasures. This report is proposed a new technique to simulate a power system based on frequency model. The result is resonable relatively with a experimental one.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1999년도 추계학술대회 논문집
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• pp.344-351
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• 1999

The safe operation of electro railways is greatly dependant on its protective systems. The system so-called Fault Protection Wire(FW) is now widely adapted to protect in AT feeding systems. It is connected between the feeder and trolley circuit to return the fault current to autotransfonmers at substation. This paper computed the distribution of fault currents at FW in the system and also evaluated the safety from electric shock when ground fault or flashover occur in the feeding system. The results show FW is useful to protect power supply network from fault in electric railways

• Asian-Australasian Journal of Animal Sciences
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• 제14권3호
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• pp.432-444
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• 2001

In this manuscript, several effective feeding and management systems to reduce environmental pollution in swine production have been briefly introduced. It is logical that reducing the excretion of nutrients in manure should be the first step to reduce the environmental impact of pig production. it is evident that the excretion of nitrogen and phosphorus can be reduced when more digestible or available feedstuffs are used. Also, it is well known that proper feed processing can reduce anti nutritional factors (ANF) and improve nutrient digestibilities. Supplementation of effective feed additives can reduce excretion of nitrogen and phosphorus due to efficient feed utilization. These include enzymes (e.g., phytase), antibiotics, probiotics, organic acids and growth hormones ($\beta$-agonists and porcine somatotropin). One of the most effective ways to reduce pollutants from swine manure is to use synthetic amino acids in feed manufacturing. Many studies showed that reduction of 2 to 4% unit (U) of dietary protein with supplemental amino acid (AA) could dramatically reduce (15 to 20%) nitrogen excretion. Regarding feeding strategies, it has been recognized that phase feeding regimen could be used to reduce nitrogen and phosphorous excretion by feeding pigs in better agreement with age and physiological state. Feeding barrows and gilts separately, known as split sex feeding, can also decrease excretion of nitrogen and phosphorus. With the increasing concerns on the negative impact of animal production systems on the environment, animal nutritionists and producers should be aware that sustainability of animal agriculture is as important as high production performance. Therefore, some feeding and management strategies described in this manuscript will help to reduce environmental pollution in swine production. Proper combination of feeding regimen and environment-friendly diet formulation through nutritional approach will be more effective to reduce nutrient excretion in swine production system compared to single approach to do so.

• Journal of Biosystems Engineering
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• 제38권4호
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• pp.295-305
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• 2013

Purpose: Recent research showed that total mixed ration (TMR) feeding for pigs improved the productivity and reduced feed cost and manure odor. An automatic TMR feeding system was developed for this study because the conventional feeder cannot deliver the TMR containing roughage. Methods: Conventional feeding systems and physical properties of TMR were surveyed, and performance tests of the conventional feeder were conducted to develop a TMR feeder. Based on the TMR feeder was developed and installed, driving, measuring weight, radio frequency identification (RFID) reading, and discharging test for feeding were conducted to ensure the performance. Results: Moisture content, density, and angle of repose of the TMR 1 (mixture of 30% cut IRG silage and 70% concentrates) were 31.6%, 387 $kg/m^3$, and $51^{\circ}$, respectively. Moisture content, density, and angle of repose of the TMR 2 (mixture of 45% concentrates, 30% cut IRG silage and by-products, 10% bean curd refuse, 10% others, and 5% fermenter) were 22.2%, 544 $kg/m^3$, and $50^{\circ}$, respectively. The coefficient of variation (C.V.) of conventional concentrate feeding were 1.9~4.1%, and C.V. of TMR containing 1~3% cut IRG roughage feeding by conventional feeder were 9~42%. The conventional disc type feeder was not suitable for TMR feeding because the supply unit was clogged. The C.V. of TMR 1 was 0.6~7.9% when 0.5~10 kg of the TMR supplied, and it was suitable for feeding grow-finish pigs and sows. On the contrary, the C.V. with TMR 2 was 28% when 0.5 kg of the TMR supplied, and it was not suitable for feeding sows. Conclusions: The TMR feeder developed in this study was suitable for feeding grow-finish pigs because the feeder performed stably with over 5.0 kg feed. However, the feeder showed a lack of accuracy for feeding sows because the amount of each feed was more than 0.5 kg per a feeding. Therefore, the improvement of outlet structure for accurate feeding is needed for sow feeding.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.641-645
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• 1996

Ball screws are used in the feeding system for transmission of driving force. The friction effect between bed and table, which can affect in accuracyin one dimension feeding and describe the dynamic feeding error, could be simplified as a specific model through experiments. The experiments for dynamic feeding errors were performed om tje NC lathe eith a ball screw. The errors in feeding were measured with respect to the variances of feed, spindle speed and motor current for feeding. A rotary encoder and a current sensor were installed with NC lathe.

• 전기학회논문지
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• 제61권3호
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• pp.485-490
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• 2012

Nowadays, in metropolitan railroad, DC feeding system is being generally applied. In order to reduce damage of electro-chemical corrosion caused by stray current and leakage current, in DC feeding system, rail is used as negative-polarity return conductor for traction load current. However, it has problem of rail potential increase and there are no adequate measures to prevent it in domestic. The rise of rail potential leads to damage for human and equipments. To solve the problems, this paper presents fundamental theory and related standards about rail potential increase. And then, we analyzed field testing data and simulated a variety of operations by using PSCAD/EMTDC as an analysis program of power system. In addition, this paper suggests rail potential limit device and addresses how to the device. To verify the effect, simulation of DC feeding system before and after the application of the device is carried out in various cases.

• Journal of Mechanical Science and Technology
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• 제19권spc1호
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• pp.403-410
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• 2005

Many daily appliances for examples copiers, printers and ATMs contain the media transport system (MTS) and the slippage between the medium in the MTS deteriorates the performance quality of the whole system. The slippage of the medium in the MTS is affected by many parameters including the friction coefficient between the feeding rollers and the medium, the velocity of the feeding rollers, and the normal force exerted on the medium by feeding rollers. This paper focuses on the effect of the normal force on the slippage while the medium is being fed. For this purpose, we developed a two-dimensional simulation model for a paper feeding system. Using the simulation model, we calculated the slippage of the paper for different normal forces. We have also constructed a testbed of the paper feeding system to verify the simulation results. Experimental results are compared with the simulation results.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2005년도 춘계학술대회논문집
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• pp.92-94
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• 2005

In this paper, when electric train is in dead-section the effect on electric train system was dealt. The feeding system of electrical railway is AC or DC. When the electric train is passed AC feeding system to DC, vice versa or phase is changed in between AC feeding systems, there is a dead section. A dead section usually makes the electrical system complex md may have an adverse effect on the electrical system inside the train. Accordingly, it is important to analyze the effect on trains in dead-section. Modeling an electric train and simulation using PSCAD/EMTDC was accomplished to analyze how power quality problem such as inverter switching surge is propagated to electric train through the feeding line, railway, pantograph.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2009년도 춘계학술대회 논문집
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• pp.33-36
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• 2009

본 연구에서는 액체로켓엔진 산화제로 과산화수소를 사용하기 위한 공급 설비 구축 및 세척 방법을 제시하고자 한다. 과산화수소 공급 설비의 오염을 최소화하기 위하여 공급 설비를 세척하고 세척된 공급 설비에 보호막을 입히는 passivation 절차를 확립하였다. 또한, 구축된 공급 설비는 누설 시험과 연소 시험을 통해서 안정성을 검증하였다.