• Journal of the Optical Society of Korea
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• 제13권2호
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• pp.272-278
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• 2009

Recently, there has been a growing interest in optical imaging of neural activity because the optical neuroimaging has considerable advantages over conventional imaging. Birefringence of the axon has been reported to change during neural activation, but the neurophysiological origin of the change is still unresolved. This study hypothesizes that the birefringence signal is at least partially attributed to the transient cellular volume change associated with nerve excitation. To examine this hypothesis, we investigated how the intensity of cross-polarized light transmitting through the axon would change as the size of the axon changes. For this purpose, a two-dimensional finite-difference time-domain program was developed with the improvement of the total-field/scattered-field method which reduces numerical noise. The results support our hypothesis in that the computed cross-polarized signals exhibit some agreement with previously-reported birefringence signals.

• 응용통계연구
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• 제26권1호
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• pp.1-14
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• 2013

미국 달러에 대한 한국원화의 17년간 일별 원/달러 환율 시계열 데이터에 대하여 정상 시계열 ARIMA 모형과 변동성을 포함한 시계열 모형인 ARIMA+IGARCH 모형을 적합하여 비교하고 예측을 실시하였다. 또한 환율 데이터에 구조변화가 있어 보이므로 선형구조를 포함한 구조 변화 모형과 자기상관 구조를 포함한 구조 변화 모형을 이용하여 변화점을 추정하고자 한다.

• 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.

• 디지털융복합연구
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• 제19권5호
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• pp.241-247
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• 2021

본 연구는 1990년도부터 2019년까지 거래소에 상장된 기업들을 대상으로 발생액 추정모형의 설명력 변화를 분석하였다. 기존의 발생액 추정모형에 사용된 재무적 변수들이 특성이 시간이 지남에 따라 변화하거나, 전체 발생액 중에서 재량적 발생액의 비중이 변화하면 모형의 설명력에도 변화가 있을 것으로 기대하고 이를 가설화하여 분석하였다. 회귀 분석결과 수정 Jones 모형(1995)은 시간의 경과에 따라 그 설명력이 점차 낮아짐을 발견하였다. 이는 발생액 자체의 증가와 모형에 포함된 변수들의 분포가 변화함에 기인하는 것으로 추정된다. 본 연구의 시계열적 분석 결과는 이익조정 연구 등 학술적인 면이나 회계 정보를 이용하는 이용자에게 중요한 시사점을 제공할 것으로 기대된다.

• 아시아태평양코퍼스연구
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• 제4권1호
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• pp.1-23
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• 2023

The Japanese language, as a typical agglutinating language, permits large noun phrases (NP) containing ten or more morphemes. In this paper, we argue that the nature of the NP in Japanese is changing. Our data are drawn from the Balanced Corpus of Contemporary Written Japanese. We conduct a series of apparent-time studies of ongoing changes in complex NPs. We first examine the length of compound nouns, followed by the usage of bound suffixes. We then examine ongoing changes in complex NPs that contain genitive case markers. Finally, we examine noun incorporation. All of our studies show a trend towards shorter, less complex NPs. Furthermore, our results suggest that the usage rate of phrases that modify the noun inside the NP (compound nouns, bound nouns, NPs containing genitive case, noun incorporation) appears to be decreasing over time. On the other hand, the usage rate of modifying material outside of the NP (positional phrases, relative clauses) appears to be increasing over time. We conclude by suggesting that our results reflect a diachronic change of decreasing synthetic morphology and increasing analytic morphology. We end by pointing out the implications of this work on our understanding syntheticity and analyticity.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2021년도 학술발표회
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• pp.372-372
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• 2021

The agriculture sector plays a vital role in the economy of Pakistan by contributing about 20% of the GDP and 42% of the labor force. Rivers from the top of Himalayas are the major water resources for this agriculture sector. Recent reports have found that Pakistan is one of the most vulnerable country to climate change that can cause water scarcity which is a big challenge to the communities. Previous studies have investigated the impact of climate change on the trend of streamflow, but the understanding of seasonal change in the regional hydrologic regimes remained limited. Therefore, a better understanding of the seasonal hydrologic change will help cope with the future water scarcity issue. In this study, we used the daily stream flow data for four major river basins of Pakistan (Chenab, Indus, Jhelum and Kabul) over 1962 - 2019. Utilizing these daily river discharge data, we calculated the winter-spring center time and the summer-autumn center times. In this study Winter-spring center time (WSCT) is defined as the day of the calendar year during which half of the total six months (Jan-Jun) discharge volume was exceeded. Results show that the four river basins experienced a statistically significant decreasing trend of WSCT, that is the center time keeps coming earlier compared to the past. We further used the Climate Research Unit (CRU) climate data comprising of the average temperature and precipitation for the four basins and found that the increasing average temperature value causes the early melting of the snow covers and glaciers that resulted in the decreasing of 1^st center time value by 4 to 8 days. The findings of this study informs an alarming situation for the agriculture sector specifically.

• 한국음향학회지
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• 제30권2호
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• pp.80-85
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• 2011

Speaker change detection involves the identification of time indices of an audio stream, where the identity of the speaker changes. In this paper, we propose novel measures for the speaker change detection based on a graph-partitioning criterion over the pairwise distance matrix of feature-vector stream. Experiments on both synthetic and real-world data were performed and showed that the proposed approach yield promising results compared with the conventional statistical measures.

• 수산경영론집
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• 제47권2호
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• pp.43-59
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• 2016

This study investigated the difference of the effects of public loan programs in fishery industry on management performance from a balanced score card (BSC) perspective depending on the type of loan, scale of fund, period of support and business category, using the financial data of fisheries firms having the balance of loan at the end of 2014. The key factors influencing credit rating change were also analyzed after public loan support. From a integrative perspective, results show that the firms supported by working fund have higher management performance than the firms supported by facility fund. The firms received large scale fund showed higher management performance than the firms received small scale fund. While management performance was decreasing or slowing down over time after financial support, management performance of the firms supported by facility fund improved over time. From a non-financial perspective, the firms received facility fund invested more in education and growing perspective than the firms received working fund. As the size of fund increased, the investment in education, growing, internal process and customer increased. Personnel expenses and employee benefits for education and growing has increased over time. However, the firms with facility fund restricted the expenses of education, personnel expenses and employee benefits as time goes by. Because the effects of public loan on credit rating of fisheries corporations have no statistical significance, it has become known that the financial support of public loan program has no influence on the change of credit rating of fisheries corporations. This study attempted performance analysis from a BSC perspective which combine factors of non-financial perspective with factors of financial perspective. Findings from this study suggest the direction of microscopic performance analysis of public loan in fishery industry.

• 대한지역사회영양학회지
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• 제8권1호
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• pp.33-40
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• 2003

This study was investigated the differences in the dietary habits and quality of diet among 148 university students in Daejeon between 1993 (71 subjects) and 2000 (77 subjects). Among male students, there were increases in height and decreases in weight, but the number in the normal weight group assessed by the BMI, increased. Significant increases in meal regularity and the rate of considering a balanced diet at meal time and significant decreases in the rate of eating unbalanced meals were noted over time among the male students. The number of male students drinking alcohol and those drinking alcohol frequently decreased significantly. When considering differences in the nutrient intake of males according to the Korean RBA, the percentages of energy, iron, and Vitamin B$_2$ decreased, while those of Vitamin C, calcium, and phosphorus increased over time. The NAR (Nutrient Adequacy Ratio) of most nutrients, especially in iron and Vitamin C were higher, than those of 1993, but the NAR of calcium, iron, Vitamin B$_2$, niacin and MAR (Mean Adequacy Ratio) were lower than 0.75 in the males. The INQ (Index of nutritional quality) of Vitamin C was higher than that of 1993, and the mQ of calcium and Vitamin $B_2$ were lower than 1 among the males. Among the females, there was no change in height and weight between 1993 and 2000, but the normal weight group, as assessed by the BMI, increased as among the males. However, unlike among the males, significant decreases in meal regularity and significant increases in the rate of alcohol drinking were noted over time. The intake of energy and nutrients showed trends similar to those among the males. The NARs of most nutrients were lower than those of 1993 among in the females. The INQs of protein, calcium, Vitamin $B_1$ and Vitamin C increased significantly, but the INQs of calcium, iron, and Vitamin $B_2$ were lower than 1 among the females. From these results, we found that male students showed relatively desirable changes over time in their dietary and health-related habits and the quality of their diets, while female students showed undesirable changes in their dietary and alcohol drinking habits and the quality of their diets.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 심포지엄 논문집 정보 및 제어부문
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• pp.65-67
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• 2004

Change of state of Channel between two wireless terminals which is caused by noise and multiple environmental conditions for happens frequently from the Wireles Network. So, When it is like that planning a wireless network protocol or performance analysis, it follows to change of state of time-varying channel and packet the analysis against a transmission efficiency is necessary. In this paper, analyzes transmission time of a packet and a packet in a time-varying and packet based Wireless Network. To reflecte the feature of the time-varying channel, we use a Signal Flow Graph model. From the model the mean of transmission time and the mean of queue length of the packet are analyzed in terms of the packet distribution function, the packet transmission service time, and the PER of the time-varying channel.