• Journal of the Korean Solar Energy Society
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• v.33 no.4
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• pp.46-50
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• 2013

This paper investigated wind turbine degradation quantitatively by analyzing the short-term operation records of the Shinan Wind Power Plant. Instead of a capacity factor which is needed to be normalized its variability due to monthly wind speed change, this study suggests an analysis method by taking the difference between the theoretical power output calculated from the nacelle wind speed and actual power output as the quantitative index of performance degradation. For three-year SCADA data analysis of the Shinan Wind Power Plant, it was confirmed that power output degradation rate of 0.54% per year. This value is within the average reduction rate 0.4%/year~0.9%/year of normalized capacity factor of the onshore wind power plants in U.K. and Denmark; however, lower than the rate 2%/year of Canadian wind power plants.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.3
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• pp.500-506
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• 2017

In 2014, ISO 55000s has been enacted and the power plant asset management is becoming a hot issue for all over the world. The asset management system is being developed as a combination of CBM(Condition Based Maintenance) and RCM(Reliability Centered Maintenance). Therefore, the research on the calculation of the failure rate which is the most basic index of RCM is actively carried out. The failure rate calculation has been going on for a long time, and the most widely used probability distribution is the Weibull distribution. In the Weibull distribution, the failure rate function is determined in three types according to the value of the shape parameter. However, the Weibull distribution has a limitation that it is difficult to apply it when the trend of failure rate changes-such as bathtub curves. In this paper, the failure rate is calculated using the mixture Weibull distribution which can appropriately express the change of the shape of the failure rate. Based on these results, we propose the necessity and validity of applying mixture Weibull distribution.

• Journal of Korea Port Economic Association
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• v.34 no.4
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• pp.181-190
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• 2018

The goal of this study is empirically to investigate the asymmetric relationship between two variables using the dry cargo freight rates and raw material price data from January 2012 to May 2018. First, we estimate the asymmetry of macroeconomic indicators of commodity prices by using a two - step threshold cointegration test. Second, the asymmetric relation test of the trade balance of existing commodity price changes is tested by bypassing to the high frequency dry cargo freight rate index. As a result of the estimation, in contrast to the existing linear analysis, each boundary value for the lower limit and the upper limit has different asymmetry. This implies that the period of fluctuation of the sudden residual that causes irregular rate of return fluctuations does not establish a long term equilibrium relationship between the raw material price and the dry cargo freight rate. Therefore, in order to consider the sudden price change in the analysis, it is necessary to include the band of inaction that controls the irregular volatility, which is consistent with the asymmetry hypothesis.

• Journal of Trauma and Injury
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• v.20 no.2
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• pp.77-82
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• 2007

Purposes: There have been many efforts to improve the service of emergency centers. In spite of these, no evidence is showing any landmark advancement of emergency services, especially in the hospital stage, exists. We need some efficient standard criteria to evaluate emergency service in the hospital stage, and a useful method might utilize the overcrowding index. We want to know the change in the overcrowding index at a regional emergency center after injury area administration. Injury area means an area in which only an assigned duty physician manages patients with injuries such as those from traffic accidents, falls, assualts, collisions, lacerations, amputations, bums, intoxication, asphyxia, drowning, animal bites, sexual assualts, etc. Methods: We started to operate an injury area in our emergency department from late 2004, and from January to June in 2004 and in 2005, we collected patients' data, age, sex, assigned department, and result from hospital order communication system to figure out overcrowding indices and result indices. We found the daily number of patients, the turnover rate, the admission rate, the ICU admission rate, the emergency operation rate, the ED stay duration, and the ED patient volume to be overcrowding indices. Also we found the withdrawal rate, the transfer rate, and mortality to be result indices. We compared these indices between 2004 to 2005 by using a t-test. Results: There was a significant increase in the daily number of visiting patients in 2005, overcrowding indices, such as the turnover rate, the admission rate, the ICU admission rate, and the emergency operation rate, also showed statistically significant increases in 2005 (P<0.001). As for the result indices, there was a noticeable decrease in the number of withdrawals (11.77/day in 2004 to 4.53/day in 2005). Conclusion: Operating an injury area in a mildly overcrowded local emergency center is beneficial. Evaluating the effect of operating an injury area and it's impact on hospital finances by conducting a similar study analyziing patients for a longer duration would be valuable.

• Korean Journal of Construction Engineering and Management
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• v.14 no.5
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• pp.103-112
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• 2013

After 1990s, the influence of construction industry has been decreased on national economy and construction business condition has been changed on economic recession and boom repeatedly. Larger fluctuation of business condition makes a forecast of it to be more difficult. Uncertainty in business prediction results in damages on construction companies and stakeholders. Therefore, study on forecasting a construction business is very important. This study suggests the Construction Industry Production Index(CIPI) to predict a construction business in consider of temperature effects. The results show that construction business is much influenced by temperature effects certainly and GDP. With the CBFM, this study examines CIPI for 2013 with two scenarios: 1)with GDP growth rate of 3.5% 2)with GDP growth rate of 2.4%. Thus, CIPI would be used as the economic state index to display the construction business conditions. Also, CIPI will be utilized as basic methodology in the impact of climate change in the construction industry.

• Korean Journal of Health Education and Promotion
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• v.13 no.1
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• pp.128-162
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• 1996

Using Random Sampling, the authors measured the body heights and weights of 31,151 persons - 17,102 in males and 14,049 in females from metropolitan, urban and rural areas between 6 to over 80 year old - for the purpose of investigating the type and the actual condition of the Korean's growth and development. At first, on the basis of the results, the authors measured the growth and development, various kinds of physiques, nutritional index of the 6 to 20s age group. Second, the authors presented the standard body weight of males and females by their body height, who were in the end of their growth (20-29 age group). Third, the authors calculated and presented the normal adapted body weight of the age group who were over 30 age after the growth had been completed. Forth, the author presented the obesity rate of the adults over 20 years old by body mass index. Finally, the authors compared chronological change of the Koreans' body heights and body weights with the results of other researchers. 1. Body Measurement Rapid growth, in terms of body height, which is described by a straight line on a growth curve has been observed among males in the ages 6-13 and among females 6-14. That growth curve turned out to be slower among the people of higher ages by both sexes. The cross-over occurred in both sexes at 11-14. The highest growth rate for a year is at 13-16 for males and 11-13 for females. This indicates that females enter a rapidly growing stage 2 years earlier than males. 2. Various Physiques and Nutritional Index Rapid growth, in terms of Relative Body Weight Index, which is described by a straight line, has been observed among males in the ages 6-16 and females in the ages 6-14. The cross-over occurred in both sexes 12.5-14.5 age in the adolescencent period. Whereupon females outgrow males. The Roher Index displayed more good value in case of females than male and in the adolescent period, the level of fullness is lower than after the completion of development. The Kaup Indices of both sexes increase with age. The index is less than 2.0 for males in 6-14 age group and for females in 6-13 age group and with this, it appeared that development of horizontal axis to long axis is poor. The index is more than 2.0 after 15 age group in males and 14 age group in females and developmental state4 age group and for females in 6-13 age group and with this, it appeared that development of horizontal axis to long axis is poor. The index is more than 2.0 after 15 age group in males and 14 age group in females and developmental state Body Mass Index is less than 20 for males 6-14 age group and for females in 6-13 age group. In the case of the higher age group, that index maintains a normal state.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.359-361
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• 2006

As circuits become increasingly complex and devices sizes shrinks, the demands placed on global planarization of higher level. Chemical Mechanical Polishing (CMP) is an indispensable manufacturing process used to achieve global planarity. In the CMP process, Diamond Disk (DD) plays an important role in the maintenance of removal rate. According to studies, the cause of removal rate decrease in the early or end stage of diamond disk lifetime comes from pad surface change. We also presented pad cutting rate (PCR) as a useful cutting ability index of DD and studied PCR trend about variable parameters that including size, hardness, shape of DD and RPM, pressure of conditioner It has been shown that PCR control ability of pressure and shape is superior to RPM and size. High pressure leads to a decrease of cell open ratio of pad surface because polyurethane of pad is destroyed by pressure. So low pressure high RPM condition is a proper removal rate sustain. By examining correlations between RPM and pressure of conditioner, it has been shown that PCR safe zoneto satisfy proper removal rate has the range 0.06mm/hr to 0.12mm/hr.

• Journal of Animal Science and Technology
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• v.65 no.6
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• pp.1254-1269
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• 2023

This study aims to predict the change in corn share according to the grazing of 20 gestational sows in a mature corn field by taking images with a camera-equipped unmanned air vehicle (UAV). Deep learning based on convolutional neural networks (CNNs) has been verified for its performance in various areas. It has also demonstrated high recognition accuracy and detection time in agricultural applications such as pest and disease diagnosis and prediction. A large amount of data is required to train CNNs effectively. Still, since UAVs capture only a limited number of images, we propose a data augmentation method that can effectively increase data. And most occupancy prediction predicts occupancy by designing a CNN-based object detector for an image and counting the number of recognized objects or calculating the number of pixels occupied by an object. These methods require complex occupancy rate calculations; the accuracy depends on whether the object features of interest are visible in the image. However, in this study, CNN is not approached as a corn object detection and classification problem but as a function approximation and regression problem so that the occupancy rate of corn objects in an image can be represented as the CNN output. The proposed method effectively estimates occupancy for a limited number of cornfield photos, shows excellent prediction accuracy, and confirms the potential and scalability of deep learning.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.2
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• pp.198-203
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• 2000

A highly viscous biopolymer from Bacillus coagulans CE-74 was purified and its rheological properties were studied The rheological properties of biopolymers produced by Bacillus coagulans CE-74 were studied at the temperature ranges with 20~8$0^{\circ}C$, at the concentration of 0.5~4.0%, at the pH ranges from 3 to 1 and at the shear rate fo 7.34~73.38 sec-1. The apparent viscosity of biopolymer was decreased with increasing shear rate, and thereby biopolymer showed pseudoplastic characteristics. Biopolymer solution showed a characteristic of non-Newtonian fluid properties. At the concentration of 1%, the consistency index and the flow behavior index were shown at 2.64 poise. sec11 and 0.8571, respectively. All dispersions were pseudoplastic fluids described accurately by Herschel-Bulkley model. The change of the biopolymer viscosity on pH showed the highest value at the pH 7.0 and it showed lower at acidic conditon that at alkaline condition comparatively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.9
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• pp.808-811
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• 2008

Optical and mechanical properties of diamond-like carbon (DLC) films synthesized by RF plasma enhanced chemical vapor deposition were investigated as a function the C/H ratio in gas mixture. The C/H ratio was varied from 6 to 10 %, adjusting the amount of $CH_4$ and $H_2$ as the source gas. The optical and mechanical properties of DLC films were characterized by UV spectrometer, Ellipsometer and Nano-indenter. The change of the C/H ratio during synthesis of DLC films had many effects on the growth rate, transmittance, refractive index and hardness. The growth rate of the films increased exponentially with the increase in C/H ratio. The hardness of the films showed the tendency to improve with increasing C/H ratio, whereas the transmittance decreased. The refractive index was varied from 2.03 to 2.17, and these refractive indexes close to 2.0 indicates that it can be applied to Si-based solar cell.