• Asian-Australasian Journal of Animal Sciences
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• 제17권3호
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• pp.371-373
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• 2004

A total of sixty 67 week-old Manina White strain laying hens were individually housed in cages to investigate feed consumption pattern during the day in relation to time of oviposition. Hourly feed intake and time of oviposition were recorded for each bird for seven days. Mean hourly feed intake of all hens showed a smaller peak at 10:00-12:00 and a larger peak at 17:00-19:00. There were no significant differences in amount of daily feed consumption and hourly eating pattern between egg-laying days and non-laying days. However, hens consumed about 10 g more feed (p<0.01) on egg-forming days (the day before oviposition) than on non-eggforming days. Hourly feed intake decreased prior to oviposition, but increased immediately during the time of oviposition. The peak consumption during the evening hours (17:00-19:00) was consistent regardless of the time of oviposition.

• Physical Therapy Rehabilitation Science
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• 제7권4호
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• pp.179-185
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• 2018

Objective: The purpose of this study was to analyze and compare vertical ground reaction forces during sit to stand (STS) and gait between female elderly and young individuals using the Wii Balance Board (WBB). Design: Cross-sectional study. Methods: Fifty-one female elderly people (age: $75.18{\pm}4.60years$), and 13 young people (age: $29.85{\pm}3.69years$) performed the five times STS test and gait respectively on the WBB. We analyzed time (s), vertical peak (%), integral summation (Int_SUM, %), and counter variables (%) in STS and 1st peak (body weight, BW%), 2nd peak (BW%), peak minimum (BW%), time (second), center of pressure (COP) path length (mm), and Int_SUM (BW%) in gait. The independent t-test was used to assess for differences in STS, gait ability, and general characteristics between the female elderly group and young adults group. With the first and last trials excluded, the mean value was obtained from the middle three of the five trials. Results: During STS, Int_SUM and time of young adults were significantly less than of the female elderly subjects. There were no significant differences in peak and counter variables. In gait, all variables (1st peak, 2nd peak, min, time, COP_path, and Int_SUM) showed significant differences between groups (p<0.05). This study demonstrated that the validity of vertical ground reaction forces occurring during STS and gait was significant in female elderly and young adults. Conclusions: Based on the measurement of vertical ground reaction forces in STS and gait using the WBB, it is possible to clinically improve the quality of geriatric physical therapy. Further studies are necessary to examine concurrent validity of elderly patients who have undergone total hip or knee replacement.

• 비파괴검사학회지
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• 제35권5호
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• pp.291-298
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• 2015

본 논문에서는 외부에서의 탐촉자 스캐닝이 어려운 금속배관의 긴 축방향 결함이나 두께감육 등과 관련된 건전성을 감시하기 위하여 펄스와전류 신호의 피크치와 피크(발생)시간을 이용하는 배열형 탐촉자를 제안하였다. 탐촉자는 관을 따라 외삽형 코일들을 배열하고, 금속배관의 상태를 반영하는 자계는 와전류에 의해 생성되는 자계이므로 원천자계가 직접적으로 센서신호에 영향을 미치는 것을 막기 위하여 코일의 외부를 페라이트로 차폐하였다. 여자코일과 센서코일은 자동적으로 연속해서 위치를 이동하게 되므로 사람이 직접 탐촉자를 주사할 필요는 없다. 두 코일의 위치가 고정되어 있을 때 센서에서 감지되는 펄스와전류 신호에서 피크치와 피크시간을 추출하고, 모든 위치에서 추출되는 이 데이터들을 축적하여 배열형 피크치 신호와 배열형 피크시간 신호를 생성하였다. 수치 모사는 시간영역은 후향차분법으로, 공간은 유한요소법을 사용하여 수행되었다. 모사 결과는 결함의 깊이나 길이가 증가함에 따라 펄스와전류 신호에서 피크치가 증가하며 피크는 더 일찍 나타난다는 것을 보여 주었으며, 이를 활용하여 본 연구에서 제안한 배열신호들은 배열형 탐촉자 내부에서 결함의 깊이나 길이 변화뿐만 아니라 결함의 위치를 반영하는데에도 탁월함을 증명하였다.

• Journal of Magnetics
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• 제17권4호
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• pp.298-301
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• 2012

In order to know the effect of surface irregularity in the detection of local wall thinning of pipeline using pulsed eddy current (PEC), the lift-off effects on PEC signal have been investigated. Three kinds of parameters in the PEC signal, which is "peak amplitude", "time to peak amplitude" and "time to zero crossing" are analyzed to separate the lift-off effects in the PEC signal. The distance from sensor to the bottom of sample which is the total thickness of combined insulator and sample is kept constant. The magnitude of the differential peak amplitude is increased with increasing sample thickness, the time to peak amplitude is increased with increasing the sample thickness. To determine the effect of lift-off, a number of balanced transient responses combining wall thinning locations and lift-off distances were plotted.

• 한국수소및신에너지학회논문집
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• 제32권5호
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• pp.410-416
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• 2021

The initial electrochemical performance of ceramic fuel cell with thin-film electrolyte was evaluated in terms of peak power density ratio, open circuit voltage ratio, and activation/ohmic resistance ratios at 500℃. Hydrogen and air were used as anode fuel and cathode fuel, respectively. The peak power density ratio reduced as ~17% for 40 minutes, which rapidly decreased in the early stage of the performance evaluation but gradually decreased. The open circuit voltage ratio decreased with respect time; however, its time behavior was remarkably different with the reduction behavior of the peak power density ratio. The activation resistance ratio increased as ~15% for 40 minutes, which was almost similar with the time behavior of the peak power density ratio.

• International Journal of Naval Architecture and Ocean Engineering
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• 제12권1호
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• pp.157-167
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• 2020

The purpose of this study is to analyze the relationship between the occurrence of intermediate peak and time duration, and to conduct a review for the causes of the intermediate peak. In this test, ice impact tests were conducted using a bow side shell frame and ice specimen. A total of 70 samples were manufactured. Two types of ice specimen with relatively different surface conditions were used. The criterion for dividing the two types of ice specimen was the different exposure times to room temperature after freezing. This experiment was conducted for each parameter in order to reproduce the actual icebreaking situation. As a result of the analysis, the intermediate peak in the ice load signal have been found to be caused by mechanisms by which the inner surface of broken ice contact with hull immediately after the initial hitting point of ice has been broken.

• 가족자원경영과 정책
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• 제10권3호
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• pp.131-148
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• 2006

The purpose of this study is to examine the allocation of time between work and leisure by the rural elderly in Korea. The data used for this study are collected from fm households during the peak ($17^{th}\;to\;30^{th}$ June) and off-peak ($28^{th}$ November to $10^{th}$ December) farming seasons of 2005 using time diary. The sample for this study consists of 120 elderly over 65 years old living in rural area in eight provinces. The major findings are as follows. (1) The time spent of farm work by rural elderly in much longer than average work hours of elderly in general regardless of farming season. The indicates that the elderly farmers are the sustaining forces of agriculture as the urban industrial sector absorbs the younger labor force rural area. (2) There are significant differences in the work time(including form work, housework, and farm work plus house work) by gender, age, education, marital status, living arrangements. (3) The rural elderly spends less time in leisure compared to the elderly in general even during the off-peak season. (4) Especially during the peak season, time allocation between work and leisure by the rural elderly is heavily skewed, resulting in an inadequate amount of time for reproduction of labor. (5) There is only significant age difference in the amount leisure time regardless of farming season. (6) Male elderly farmers work approximately 30 minutes to 1 hour longer on farm than the females do, but the total work time (farm work plus housework) of female elderly is longer than that of the male elderly. There is no significant gender difference in the amount of leisure time during the peak season, whereas the men have more leisure than the women during the off-peak season. To conclude, the gender differences in time allocation among the rural elderly are minimal. However, the rural elderly of both genders suffers from excessive work hours and heavy workload compared to the urban counterpart.

• 한국수자원학회논문집
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• 제50권1호
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• pp.65-73
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• 2017

본 연구는 청미천 유역을 대상으로 1985년부터 2015년까지의 가뭄지수를 이용하여 첨두 가뭄심도와 가뭄기간을 분석하였다. 이을 위해 기상학적 가뭄지수로는 강수량만을 변수로 하는 SPI (Standardized Precipitation Index)와 강수량과 증발산량을 함께 고려하는 SPEI (Standardized Precipitation Evapotranspiration Index)를 적용하였으며, 수문학적 가뭄지수는 유역의 유출량을 변수로 하는 SDI (Streamflow drought index)를 적용하였다. SDI의 경우 청미천 유역을 구축한 SWAT 모형을 이용하여 도출한 유출량을 사용하였다. 그 결과 첨두 가뭄심도의 발생시기는 SPI, SPEI의 발생 후에 SDI가 발생하는 양상을 보였으며 평균적으로 SDI와 SPI는 0.59개월, SPEI는 0.72개월의 차이를 보인다. 최대 발생지체 시간은 SPI, SPEI 모두 2개월을 보인다. 또한 기상학적 가뭄이 해결될 수 있는 강우량임에도 수문학적 가뭄을 해결하지 못하는 경우가 발생함을 확인하였다.

• Water Engineering Research
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• 제2권4호
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• pp.219-229
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• 2001

Synthetic unit hydrograph equations for rainfall run-off characteristics analysis and estimation of design flood have long and quite frequently been presented, the Snyder and SCS synthetic unit hydrograph. The major inputs to the Snyder and SCS synthetic unit hydrograph are lag time and peak coefficient. In this study, the methods for estimating lag time and peak coefficient for small watersheds proposed by Zhao and McEnroe(1999) were applied to the Kum river basin in Korea. We investigated lag times of relatively small watersheds in the Kum river basin in Korea. For this investigation the recent rainfall and stream flow data for 10 relatively small watersheds with drainage areas ranging from 134 to 902 square kilometers were gathered and used. 250 flood flow events were identified along the way, and the lag time for the flood events was determined by using the rainfall and stream flow data. Lag time is closely related with the basin characteristics of a given drainage area such as channel length, channel slope, and drainage area. A regression analysis was conducted to relate lag time to the watershed characteristics. The resulting regression model is as shown below: ※ see full text (equations) In the model, Tlag is the lag time in hours, Lc is the length of the main river in kilometers and Se is the equivalent channel slope of the main channel. The coefficient of determinations (r$^2$)expressed in the regression equation is 0.846. The peak coefficient is not correlated significantly with any of the watershed characteristics. We recommend a peak coefficient of 0.60 as input to the Snyder unit-hydrograph model for the ungauged Kum river watersheds

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.96.6-96
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• 2001

A high peak power demand at substations will result under Moving Block Signalling (MBS) when a dense queue of trains begins to start from a complete stop at the same time in an electrified railway system. This may cause the power supply interruption and in turn affect the train service substantially. In a recent study, measures of Starting Time Delay (STD) and Acceleration Rate Limit (ARL) are the possible approaches to reduce the peak power demand on the supply system under MBS. Nevertheless, there is no well-defined relationship between the two measures and peak power demand reduction (PDR). In order to attain a lower peak demand at substations on different traffic conditions and system requirements, an expert system is one of the possible approaches to procure the appropriate use of peak demand reduction measures ...