• 풍력에너지저널
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• 제15권1호
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• pp.69-81
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• 2024

In order to understand water depth distribution in the waters of the southwestern sea offshore wind power demonstration complex, field observations were conducted using a multi-beam echosounder from before construction (2018.2) to operation (2022.8). After data processing and correction of the observed depth, cross-sectional analysis was performed to calculate the maximum water depth value, and time phase analysis was performed using the maximum water depth value. The maximum water depth change rate over time tended to gradually decrease, and there was little difference in the rate of change before the construction of the wind turbine foundation structure, and the rate of change was rapid when the foundation structure was under construction. As a result of time phase analysis, the rate of change of the first (2018.02) and the second (2018.05) showed a rate between -6.27 and -4.13, on average, as the rate of change before the construction of the offshore wind farm, and there was no difference between the first and second rates. The third (2018.11) rate of change was -4.25 to -1.82, and the fourth (2019.04) rate of change was -2.34 to -1.22, and the rate of change increased rapidly after the third time. The fifth (2019.07) rate of change was -2.11 to -1.31, the sixth (2021.05) rate of change was -2.09 to -1.28, and the seventh (2022.08) was -2.11 to -1.22 rate of change, and after the rate of change reached some extent, the change was analyzed in an insufficient graph.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2008년도 추계 학술논문 발표대회
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• pp.89-92
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• 2008

This research analyzed the basic characteristics of unhardened concrete and the compression strength characteristics of hardened concrete according to liquidity retention agent mix rate change to improve the liquidity fluidity retention performance of high performance concrete, and produced the following results. The moment fluidity retention agent is added according to fluidity retention agent mix rate change, which increased fluidity retention agent mix rate, slump flow decreased, and in the case of slump flow according to the progress time change by the fluidity retention agent mix rates, the more fluidity retention agent mix rate increased, the lower slump flow change rate became. The moment fluidity retention agent is added according to fluidity retention agent mix rate change, fluidity retention agent mix rate increased compared to non-mixture of fluidity retention agent, and the air amount by progress time change by the fluidity retention agent mix rates slightly increased, however target range is still met and unit volume mass is inversely proportional to air amount. Compression strength according to age progress by the fluidity retention agent mix rates was shown to increase slightly with increase in fluidity retention agent mix rate, and yet the difference was not significant.

• 대한안전경영과학회지
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• 제14권3호
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• pp.85-92
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• 2012

In this study the real situation of apartment house in seoul is reproduced with multi-zone modeling program contam2.4. This model include immune building system(disinfection system) which is consist of dilution, Filter Technology and UVGI(ultra violet germicidal irrdiation). In this study experiments design method used for estimating interaction of HRV air change rate, UVGI air change rate and UVGI grade. Result show that HRV air change rate and UVGI air change rate is most influence factor for remove rate. also Interaction of HRV air change rate and UVGI air change rate is ost influence factor for remove rate.

• International Journal of Reliability and Applications
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• 제2권3호
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• pp.199-207
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• 2001

The failure rate functions between successive failures are of concatenated form. We allow the parameters of failure rate function change after a certain failure and its fixing. We confine out attention to a model wherein the interfailure times are described by its failure rate function. We suggest an adaptive failure rate function with a change-point under the assumption that interfailure times are record value statistics from a Weibull distribution. The proposed model will be applied through a practical example of software failure data.

• 대한음성학회지:말소리
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• 제64호
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• pp.15-37
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• 2007

The purpose of this paper is to examine the change of the times on the transmission rate of broadcast message. In order to find out the research results, I collected past recorded news tapes and selected 22 radio news out from era of Japanese Imperialism, 1950's, 1960's and contemporary age. Next I measured each announcer's reading rate, and compared change on news-reading rate between present and past approximately 50 years ago. The results of study with such procedures and methods are as follows : the average reporting rate of newscasters in each era is different. From these results, we can easily grasp diachronic change in the transmission rate of broadcast message. Namely, the results show us that present announcers read news faster than the group of past era of Japanese Imperialism by 68%.

• Journal of Preventive Medicine and Public Health
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• 제4권1호
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• pp.1-18
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• 1971

Eleven nonathletes and eleven athletes were exercised on a standardised Harvard step test, and the average rate of change in QRS amplitude in lead III of the electocardiogram associated with heart rotation and the average change in rate of heart beat were observed. 1. After the Harvard step exercise, the average rate of change in QRS amplitude in lead III of both groups increased. This was due to the clockwise rotation of the heart and was associated with respiratory movement. The diaphragm was inferred to remain for a while in a relatively more inspiratory position. 2. After the Halved step exercise, a high correlation between the recovery of the average rate of change in QRS amplitude in lead III and the average change in rate of heart beat was observed in the athletic group. 3. In the nonathletic group there was no significant correlation between the average rate of QRS amplitude change and the average rate of change of heart beat. 4. Athletes were assumed to be trained to ventilate quickly at their maximum ability, using deep descending movements of the diaphragm and other respiratory musclature. Consequently, the average in rate of heart beat also recovered quickly. 5. Nonathletes were inferred not to have been trained to adjust quickly to ventilate so efficiently with their diaphragm movement and other respiratory musculature, and are characterised by their longer time to complete recovery.

• 전기의세계
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• 제29권7호
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• pp.455-459
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• 1980

The gain change of the photomultiplier which occurs as the count rate increased was examined. and simple feedback resistor series was introduced between 7th and 9th dynode for compensating the gain change. The effect of the feedback resistor series was considerably good to reduce the gain change. With the feedback resistor, the gain change was only 1.9%, when count rate was increased from 514 CPS (counts per second) to 1250 CPS. Without the feedback resister, the gain change was 6.9%, when the count rate was increased from 530 CPS to 1250 CPS.

• 대한수학교육학회지:수학교육학연구
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• 제27권1호
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• pp.1-22
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• 2017

본 연구에서는 고등학교 1학년 학생들을 대상으로 학생들이 함숫값의 변화를 인식하는 과정에서 어떠한 변화율 개념을 가지고 있는지 확인하고, 변화율 개념에 따라 어떻게 구간에서 함수의 변화를 인식하고 표현하는지에 대하여 6차시에 걸친 교수실험을 실시하였다. 그 결과 학생들이 함수의 변화를 분석하는데 변화율 개념을 이용되기는 하지만, 학생들의 변화율에 대한 인식과 표현이 다양하고 이에 따라 평균변화율에 대한 인식에 있어서도 차이가 나타나는 것으로 관찰되었다. 다만 이 차이를 질적인 수준차로 보아야할 것인지에 대하여는 추후 연구가 필요할 것으로 보인다. 본 연구는 변화율에 대한 학생의 인식을 세밀하게 조사한 연구로써 향후 변화율 관점에서의 미분학습에 대한 연구에 기초자료가 될 것으로 기대된다.

• Journal of the Korean Data and Information Science Society
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• 제14권3호
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• pp.641-651
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• 2003

This study suggests the hybrid models for interest rate forecasting using structural changes (or change points). The basic concept of this proposed model is to obtain significant intervals caused by change points, to identify them as the change-point groups, and to reflect them in interest rate forecasting. The model is composed of three phases. The first phase is to detect successive structural changes in the U. S. Treasury bill rate dataset. The second phase is to forecast the change-point groups with data mining classifiers. The final phase is to forecast interest rates with backpropagation neural networks (BPN). Based on this structure, we propose three hybrid models in terms of data mining classifier: (1) multivariate discriminant analysis (MDA)-supported model, (2) case-based reasoning (CBR)-supported model, and (3) BPN-supported model. Subsequently, we compare these models with a neural network model alone and, in addition, determine which of three classifiers (MDA, CBR and BPN) can perform better. For interest rate forecasting, this study then examines the prediction ability of hybrid models to reflect the structural change.

• KIEAE Journal
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• 제12권6호
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• pp.29-38
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• 2012

The current building energy efficiency rating certification regulation on apartment houses evaluates only the saving rate of energy consumed during operation, i.e. use, of a building, but doesn't consider the energy consumptions and environmental load($CO_2$) emissions occurring during the whole lifetime of a building. So this study calculated the energy consumptions and environmental load emissions occurring during the whole lifetime of a building, selected reference schemes and alternative items by design variables to present a design draft considering energy efficiency and environmental performance, and evaluated the total cost by combining and calculating its direct cost(material and heating cost) and indirect cost(environmental cost), for an existing apartment house as an evaluation object. As a result of analysis, the change of heating cost by alternative items of design variables showed a 4~8% change rate compared to the reference scheme, and the material cost of design variable 7 showed a maximum 4.4 times change rate in the alternative plan 6 compared to the reference scheme. The environmental cost showed a similar change rate to the material cost change rate in general, but showed a similar environmental cost change rate to the heating cost change rate in case of design variables 4-1, 4-2, 7.