• 대기
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• 제24권3호
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• pp.379-390
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• 2014

This study explores the long-term trends of surface air temperatures in 11 KMA stations over the period of 1960~2012. Both linear and nonlinear trends are examined for the $95^{th}$, $50^{th}$, and $5^{th}$ percentiles of daily maximum ($T_{max}$) and minimum temperatures ($T_{min}$) by using quantile regression method. It is found that in most stations linear trends of $T_{max}$ and $T_{min}$ are generally stronger in winter than in summer, and warming trend of the $5^{th}$ percentile temperature (cold extreme) is stronger than that of the $95^{th}$ percentile temperature (warm extreme) in both seasons. The nonlinear trends, which are evaluated by the second order polynomial fitting, show a strong nonlinearity in winter. Specifically, winter temperatures have increased until 2000s but slightly decreased afterward in all percentiles. This contrasts with the $95^{th}$ and $50^{th}$ percentiles of summer $T_{min}$ that show a decreasing trend until 1980s then an increasing trend. While this result is consistent with a seasonal dependence of the recent global warming hiatus, most of the nonlinear trends are statistically insignificant, making a quantitative attribution of nonlinear temperature trends challenging.

• Fisheries and Aquatic Sciences
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• 제2권2호
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• pp.199-209
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• 1999

Before investigating the long-term variations in macrobenthic communities sampled in the Chokchon macrotidal flat in Inchon, Korea, from 1989 to 1996, we need to understand how environmental factors in the area vary. As potential governing agents of tidal flat communities, abiotic factors such as mean sea level, seawater, air temperature, and precipitation were considered. Data for these factors were collected at equal intervals from 1976 or 1980 to 1996, and were analyzed using a decomposition method. In this analysis, all the above variables showed strong seasonal nature, and yielded a significant trend and cyclical variation. Positive trends were seen in the seawater and air temperatures, and based upon this relationship, it was found that the biological sampling period of our program has been carried out during warmer periods in succession. This paper puts forth some hypotheses concerning the response of tidal flat macrobenthos communities to the changing environment including mild winters in succession.

• Membrane and Water Treatment
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• 제10권5호
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• pp.339-352
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• 2019

Long term water quality change was analyzed to evaluate the effect of the Total Maximum Daily Load (TMDL) policy. A trend analysis was performed for biochemical oxygen demand (BOD) and total phosphorus (TP) concentrations data monitored at the outlets of the total 41 TMDL unit watersheds of the Nakdong River in the Republic of Korea. Because water quality data do not usually follow a normal distribution, a nonparametric statistical trend analysis method was used. The monthly mean values of BOD and TP for the period between 2004 and 2015 were analyzed by the seasonal Mann-Kendall test and the locally weighted scatterplot smoother (LOWESS). The TMDL policy effect on the water quality change of each unit watershed was analyzed together with the results of the trend analysis. From the seasonal Mann-Kendall test results, it was found that for BOD, 7.8 % of the 41 points showed downward trends, 26.8 % and the rest 65.9% showed upward and no trends. For TP, 51.2% showed no trends and the rest 48.8% showed downward trends. From the LOWESS analysis results, TP began to decrease in most of the unit watersheds from mid-2010s when intensive chemical treatment processes were introduced to existing wastewater treatment plants. Overall, for BOD, relatively more points were improved in the main stream compared to the points of the tributaries although overall trends were mostly no trend or upward. For TP, about half of the points were improved and the rest showed no trends.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.472-476
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• 2015

The purpose of this study is to fully understand the present state of the domestic construction companies, and to analyze phased business types and construction management techniques in order to initiate overseas expansion. Because of the recession in the domestic construction market, a thorough and strategic perspective to constantly develop inroads into overseas market is required. So we carried out a questionnaire survey targeting the experts of the overseas construction and researcher, and consulted them in depth. The questionnaire survey was divided into three sections. The first section is the necessity of overseas construction and the reason. The second is the overseas business types classified into the way of advance in short-term and long-term phase possibility of expansion. Lastly, the importance of the phased construction management techniques and the current capacity of the domestic and the foreign business trends were scrutinized. On the basis of the consultation and surveys, we analyzed the overseas business types and the construction management types in the short-term and long-term phase.

• 간호행정학회지
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• 제20권1호
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• pp.95-105
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• 2014

Purpose: The purpose of this study was to examine trends in number of nursing staff and skill mix. Methods: Nursing staff and skill mix were measured using the number of nursing staff including nurse aids and registered nurses per bed. Descriptive and panel data regression analyses were conducted using data on long-term care hospitals which included yearly series data from 2006 to 2010 for 119 hospitals. Results: The number of nursing staff per bed increased significantly but percentage of registered nurses decreased significantly from 2007 to 2010. The regression model explained this variation as much as 34.9% and 43.8%. Conclusion: The results showed that in long-term care hospitals there were more nurse aids employed instead of registered nurses after the implemention of differentiated inpatient nursing fees. Thus clarifying the job descriptions for nurses and nurse aids is needed and appropriate hospital incentive policies should be implemented.

• 한국물환경학회지
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• 제20권1호
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• pp.63-71
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• 2004

The long-tenn trend analyses of water qualities were performed for 49 monitoring stations located in Nakdong River. Water quality parameters used in this study are the monthly data of BOD(Biological Oxygen Demand), TN(Total Nitrogen) and TP(Total Phosphorus) measured from 1990 to 1999. The long-tenn trends were analyzed by Seasonal Mann-Kendall Test and Locally WEighted Scatter plot Smoother(LOWESS). Nakdong river was divided into four subbasins, including upstream watershed, midstream watershed, western downstream watershed and eastern downstream watershed. The results of Seasonal Mann-Kendall Test indicated that there would be no trends of BOD in upstream watershed, western and eastern downstream watershed. Trends of BOD were downward in midstream watershed. For TN and TP, there were upward trends in all of watersheds. But LOWESS curves suggested that BOD, TN and TP concentrations generally increased between 1990 and 1996, then resumed decreasing.

• 동력기계공학회지
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• 제13권2호
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• pp.63-70
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• 2009

This paper discusses the influence on long-tenn predictions of the ship response in ocean by using the Global Wave Statistics data, GWS, and wave information from the remote sensing satellites. GWS's standard scatter diagrams of significant wave height and zero-crossing wave period are suggested to be corrected to a round number of 0.01/1000 fitted with a statistical analytic model of the conditional lognormal distribution for zero-crossing wave period. The GEOSAT satellite data are utilized which presented by I. R. Young and G. J. Holland (1996, named as GEOSAT data). At first, qualities of this data are investigated, and statistical characteristic trends are studied by means of applying known probability distribution functions. The wave height data of GEOSAT are compared to the data observed onboard merchant ships, the data observed by measure instrument installed on the ocean-going container ship and so on. To execute a long-tenn prediction of ship response, joint probability functions between wave height and wave period are introduced, therefore long-term statistical predictions are executed by using the functions.

• 전자통신동향분석
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• 제30권3호
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• pp.123-130
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• 2015

본고는 TDD(Time Division Duplex)/FDD(Frequency-Division Duplex) 네트워크 컨버전스를 통해 LTE(Long Term Evolution) 서비스를 제공하고 있는 주요 사업자들의 동향에 대하여 분석 정리하였다. 본고의 분석 결과에 따르면, 상당수 사업자가 보유 주파수 여건을 고려하여 경쟁력을 높이기 위한 목적으로 네트워크 컨버전스를 추진한 것으로 나타났다. 향후 국내에서도 TDD/FDD 컨버전스를 촉진하고 주파수 이용 효율성을 개선하기 위한 정책방안에 대한 모색이 필요하다고 사료된다.

• 신재생에너지
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• 제19권4호
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• pp.98-107
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• 2023

A study was conducted to analyze data from 1981 to 2020 for understanding the impact of climate on solar energy generation. A significant increase of 104.6 kWhm^-2 was observed in the annual cumulative solar radiation over this period. Notably, the distribution of solar radiation shifted, with the solar radiation in Busan rising from the seventh place in 1981 to the second place in 2020 in South Korea. This study also examined the correlation between long-term temperature trends and solar radiation. Areas with the highest solar radiation in 2020, such as Busan, Gwangju, Daegu, and Jinju, exhibited strong positive correlations, suggesting that increased solar radiation contributed to higher temperatures. Conversely, regions like Seosan and Mokpo showed lower temperature increases due to factors such as reduced cloud cover. To evaluate the impact on solar energy production, simulations were conducted using climate data from both years. The results revealed that relying solely on historical data for solar energy predictions could lead to overestimations in some areas, including Seosan or Jinju, and underestimations in others such as Busan. Hence, considering long-term climate variability is vital for accurate solar energy forecasting and ensuring the economic feasibility of solar projects.

• 한국산학기술학회논문지
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• 제21권5호
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• pp.191-205
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• 2020

본 연구는 노인장기요양시설에서 인적서비스 중심으로 제공되는 요양서비스의 한계를 보완하기 위해 요양시설 종사자들의 가상현실이나 인공지능 탑재 로봇 등의 차세대 기술의 활용 가능성에 대한 인식을을 탐색하고자 하였다. 조사대상은 노인장기요양시설 종사자로 하였으며, 시설의 직군별로 이질적인 세 집단(요양보호사, 사회복지사, 원장)을 구성하여 총 14명에 대한 포커스 그룹 인터뷰를 실시하였다. 인터뷰 내용은 노인장기요양시설에 차세대 기술 도입의 장점과 장애요인, 그리고 앞으로의 적용가능성 등에 관한 것이었으며, 분석 결과 총 3개의 주제와 8개의 범주, 26개의 하위 범주가 도출되었다. 연구의 주요 결과로, 차세대 기술 활용시 노인의 개인적 측면에서 노인의 심리·정서적 안정 효과, 호기심과 흥미 제공, 신체적 활동 욕구의 해소가 장점으로 기대되었으며, 요양서비스 인력의 입장에서는 신체적 활동제약 노인에게 유용한 서비스 제공, 배회 노인의 효과적 관리가 시설운영자의 입장에서는 시설의 홍보 활용이나 시대적 흐름에의 부합, 직원 교육의 유용성을 장점으로 기대되었다. 노인장기요양시설의 인력인 참여자들은 요양시설에 차세대 기술 도입시 예상되는 문제점에 대해서도 언급하였지만 다양한 측면의 장점이 더 많을 것으로 예상하였다. 미래에 요양서비스 분야에 차세대 기술이 도입되어 활용된다면 노인복지와 노인공학 발전에도 기여할 것이다.