• Journal of Biosystems Engineering
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• 제43권2호
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• pp.83-93
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• 2018

Purpose: This study derived the consumed power and load characteristics of a tillage operation performed in an upland field located in Seomyeon, Chuncheon, Rep. Korea, where potatoes and cabbages were cultivated in two crops. Methods: A plow and rotavator were mounted on a tractor with 23.7 kW of rated power to perform the tillage operation. The work conditions were determined, considering the actual working speed of the tillage operation performed by the local farmers. The power consumption of the rear axle, engine, and power take-off (PTO), PTO torque, and tractive force were measured under each work condition. The consumed power and load characteristics were analyzed using their average values. Results: The rotary-tillage operation consumed more engine power than the plow operation for the same tractor-transmission gear condition. The PTO in the rotary-tillage operation and the rear axle in the plow operation consumed the most power. The power consumption of the engine and the PTO for the rotary-tillage operation tended to increase as the transmission gears of the tractor and the PTO became higher. In contrast, the rear-axle power consumption was insignificant. In addition, the PTO torque tended to rise as the tilling pitch increased. For the plow operation, the drawbar power and the rear axle power accounted for 68-90% of the engine power. The engine and rear axle power, drawbar power, and tractive force tended to rise as the working speed increased. Conclusions: The power consumption and load characteristics differed for the plow and rotary-tillage operations. They may also differ depending on the soil conditions. Therefore, the power consumption and load characteristics in various work environments and regions should be analyzed, and reflected in the design of tractors and working implements. The results derived from this study can be used as a reference for such designs.

• 전기학회논문지
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• 제59권2호
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• pp.311-317
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• 2010

This paper deals with operation characteristics of a written-pole motor (WPM), having that of a permanent magnet (PM) synchronous motor and induction motor at once. The WPM also has a magnet layer on the surface of the rotor and the exciter pole that is a device to make the magnet layer magnetized during the operation. This study, introducing a fundamental structure and operation characteristics of a single-phase WPM, proposes a initial design method. With those ground, a 130W, single-phase WPM that is designed for a home appliance is presented and verified with a performance through the experiment.

• Journal of information and communication convergence engineering
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• 제5권2호
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• pp.126-130
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• 2007

This paper proposes a method that automatically extracts characteristics of cracks such as length, thickness and direction, etc., from a concrete surface image with image processing techniques. This paper, first, uses the closing morphologic operation to adjust the effect of light extending over the whole concrete surface image. After applying the high-pass filtering operation to sharpen boundaries of cracks, we classify intensity values of the image into 8 groups and remove intensity values belong to the highest frequency group among them for the removal of background. Then, we binarize the preprocessed image. The auxiliary lines used to measure cracks of concrete surface are removed from the binarized image with position information extracted by the histogram operation. Then, cracks broken by the removal of background are extended to reconstruct an original crack with the $5{\times}5$ masking operation. We remove unnecessary information by applying three types of noise removal operations successively and extracts areas of cracks from the binarized image. At last, the opening morphologic operation is applied to compensate extracted cracks and characteristics of cracks are measured on the compensated ones. Experiments using real images of concrete surface showed that the proposed method extracts cracks well and precisely measures characteristics of cracks.

• 한국유체기계학회 논문집
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• 제18권3호
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• pp.20-25
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• 2015

In this study, there are 6 mixers that are installed in a 600,000 barrel tank. We identified internal flow characteristics of floating roof tank with varying the number of operation from 4 to 6 because mixer is a variable that influence flow characteristics of the tank. And while varying an angle from Right $60^{\circ}$, Right $30^{\circ}$, Left $30^{\circ}$ to Left $60^{\circ}$, we identified internal flow characteristics of the tank. As a result, maximum velocity of flow was 0.02m/s stationarily when we changed the number of operation from 4 to 6. Maximum velocity of flow by change of an angle was from 0.42m/s to 0.47m/s. Therefore, we identified that these factors don't have a great influence on internal flow characteristics of a tank by investigating results with varying the number of operation and an angle.

• 기본간호학회지
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• 제4권2호
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• pp.245-265
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• 1997

The purpose of this study was to promote the effectiveness in managing disease or injury, by examining the length of stay in hospital according to characteristics concerned before and after operation, and by serving as a basis for reducing that length. As a result of investigating the length of stay in hospital according to inpatient's personal characteristics, clinical features and other characteristics concerned, the following characteristics appeared significant. The characteristics that showed a significant difference about the length of stay in hospital before and after operation were the age and the fact whether one was married or not among inpatient's personal characteristics. The significant ones among clinical features were the route to be taken to hospital, the form of insurance, the experience of re-hospitalization, whether another disease coexisted, the experiment of changing department, whether a diagnosis was determined by consultation, whether an intensive care unit was used, whether re-operation was performed, the total number of case of the experience of re-hospitalization, inpatient who were again sent to hospital under the same diagnosis was not included in the investigation, which was pointed out as a limit in this study. The significant ones among other characteristics concerned were the date and season when the patients were taken to hospital and the doctor in attendance. The doctor in attendance appeared to give a significant impact on the length of stay in hospital before operation, but no significant difference was noted in the mean among the doctors in attendance. And those characteristics were not found regularly among the selected departments. As stated above, one way to reduce the length of stay In hospital was to diminish the length of stay in hospital before operation. The term of hospitalization before operation shall be reduced by grasping the factors that affected that length before operation and by conducting examination as many as possible in the out-patient department. Also, the efforts should be put on that length after operation. The management of hospital seemed to be successfully carried out if those factors affected that length were effectively controlled.

• 간호행정학회지
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• 제14권3호
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• pp.249-259
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• 2008

Purpose: This study was performed to identify the patient characteristics significantly affecting nursing outcomes and their predictability in gastrointestinal surgery patients. Method: The subjects were 149 abdominal surgery patients from 3 general surgical nursing units of 3 general hospitals. Two instruments were used to measure nursing outcomes and acuity of the subjects. The nursing outcomes were measured at post-operation 4 and 7days using review of patients' records, observation of patients, and interviews with patients by a trained nurse. For data analysis, T-test or ANOVA, Pearson Correlation and Stepwise Multiple Regression were done. Result: Age, severity score, diagnosis, cancer or not, operation site were the subjects' characteristics that were significantly related to the nursing outcomes in both post-operation 4 and 7days. Cancer or not, age, diagnosis and severity score were the significant predictors for the scores of nursing outcome in post-operation 4days and the predictability was 34.9%. The predictability of cancer or not was highest, 22.6%. Age, diagnosis and cancer or not were the significant predictors for the scores of nursing outcome in post-operation 7days and the predictability was 27.8%. The predictability of age was highest, 17.3%. Conclusions: The patient characteristics affecting nursing outcomes should be considered when nursing care is planned and provided. Especially, careful attention should be given to the patients with cancer and older age. And, these patient characteristics should be adjusted for correct estimation of the effectiveness of nursing interventions on nursing outcomes.

• 한국산학기술학회논문지
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• 제8권6호
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• pp.1325-1331
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• 2007

본 연구에서는 냉방운전 시 가변용량방식의 압축기를 적용한 시스템 에어컨의 냉방능력과 증발기 및 응축기의 온도특성을 조사하기 위해 압축기 운전율(10가지)과 실내외 온도(16가지)의 변화에 따른 시스템의 운전특성을 실험적으로 조사하였다. 시스템의 운전특성은 칼로리미터를 이용하여 측정되었다. 냉방능력은 실외온도가 낮아질수록 실내온도가 증가할수록 더 큰 값을 그리고 압축기 운전율이 증가할수록 냉방능력은 선형적으로 증가하였다. 응축온도는 실외온도 변화에 증발온도는 실내온도 변화에 더 민감하였다. 또한 압력-엔탈피선도를 이용하여 사이클의 운전특성을 분석하였다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2000년도 봄 학술발표회논문집
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• pp.332-339
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• 2000

In this paper the characteristics of vibration induced by subway trains running on track is discussed. The quantitative prediction of the vibration level and the countermeasure for reduction of necessary, is of importance for the better environment. It was made the constructed Bundang line as first step with the modified Young-Dan type to basis on the Japanese Young-Dan type. In this paper it was measured and analyzed to two region (①Susuh-Bokjung, ②Chorim-Suhyun region) of this, at present operational Bundang line when averaging velocity of train is 60(㎞/h). As the response characteristics of frequency induced by subway operation, it was confirmed that frequency band of neighborhood of 30∼80Hz in generally dominant. Also to assess the quantitative vibration as response level to be measured for each point of two region in subway operation, the vibrational response level was measured at the state to be not subway operation. And the level was approximately 1/5∼1/10 level comparing to subway operation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 A
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• pp.102-105
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• 1993

The objective of this study is to solve the operation scheduling problem of plural battery energy storage systems (BESS), and to find useful intonation from its result. Unlike conventional energy storage system, BESS has on hardware characteristics such as high efficiency, fast-acting response and operational loss. Considering rate constraints of thermal unit power as well as hardware characteristics of BESS, the operation scheduling has an intricated problem. In order to solve this optimization problem, we use successive approximations dynamic programming. In two types of operation, the proposed algorithm is applied to test system. one is daily optimal operation, the other weekly optimal operation.

• International journal of advanced smart convergence
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• 제9권2호
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• pp.105-113
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• 2020

In this paper, we proposed a soft switched synchronous boost converter, which can perform discharging the battery, is proposed. The proposed converter has low switching loss even at high frequency operation due to its soft switching characteristics. The converter operates in synchronous mode to minimize conduction loss because of changing the rectified diode to MOSFET with a low on resistance. In this reason, the efficiency of the converter can be greatly improved in high frequency. In this paper, the battery discharger with a switching frequency of 100 kHz, has been designed. The designed converter also simulated to prove the converter's characteristics of synchronous operation as well as soft switching operation. The simulation shows that the proposed converter always meets the soft switching conditions of turning on and off switching in the zero voltage and zero current states. Therefore, simulation results have confirmed that the proposed battery discharge had soft switching characteristics. The simulation results have confirmed that the proposed battery discharger had soft switching and synchronous operation characteristics.