• 대한공간정보학회지
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• 제19권4호
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• pp.3-12
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• 2011

침전물 변화의 이해는 수질모니터링에 있어서 중요한 요소이다. 수질 변수는 시공간에 의해 변하므로 시간분석이나 공간분석 한 가지만으로는 모형화하거나 명확히 설명하기 어렵다. 본 연구에서는 1985년부터 2005년까지 메콩강 하류 유역에서 수집된 침전물 기록과 공간 자료를 근거로 온도, 페하 수준 및 용존산소 수준을 파악하고, 역거리가중법을 이용하여 시공간 경향과 시각 분석을 평가하고자 한다. 그 결과, 온도와 페하의 최대값은 이 기간 동안 큰 변화없이 나타났고 최대 용존산소는 2002년까지 점점 증가하여왔다. 최소 페하와 용존산소는 이 기간 동안 불안정한 경향으로 변화하였다. 역거리가중법 보간을 이용한 경향 분석에서는 연구 지역의 전반적인 수온이 계속 증가했다는 것을 보여주었고, 페하는 1993년부터 2005년 동안 감소하는 경향을 나타냈다. 용존산소농도는 1989년 이후 증가하였고 2002년부터는 많이 확산되지 않았다.

• 디자인학연구
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• 제15권1호
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• pp.101-112
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• 2002

디자인의 변천사는 시대적 상황이나 사회적 유행에 따라 시시 각각으로 다양하게 변화되어 왔다. 디자인의 가치 또한 다양한 방법으로 판단되고 인정되어 새로운 트렌드의 출현과 발전을 거듭해 왔다. 실용적 생활을 위한 다양한 디자인적 조형의 추구는 보다 풍요로운 삶과 여유를 가져다주었으며, 자동차의 조형 디자인 추구는 과학기술의 눈부신 성장과 발전에 따라, 이제는 과거 그 어느 때 보다도 디자인에 대한 기대와 중요성이 확대되어 요구되어지고 있다. 그것은 기술적, 기능적 측면의 고도화 단계에 있는 최근의 '기술적 평준화' 상황에 있어서 세계시장의 승부는 소비자의 니즈(Needs)에 부합하는 차별화 디자인으로 귀결되기 때문이다. 본 연구는 자동차 디자인에 있어서 근 미래 디자인 트렌드를 예측함으로써 향후 자동차 디자인의 경쟁력 확보를 위한 방향으로 고찰하였다. 연구는 우선 디자인 트렌드의 변화에 의한 시대별 디자인 가치변화의 흐름과 21세기 사회변화의 양상과 그에 따른 소비자 가치관의 변화를 분석하였고, 시대별, 지역별로 자동차와 제품디자인의 트렌드를 비교 연구하였으며 미래 디자인 예측은 미국, 유럽, 일본 등 자동차 선진국의 최근에 나타나고 있는 자동차 디자인 현상을 여러 측면에서 조사, 분석하여 정리하였다.

• 농촌계획
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• 제29권4호
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• pp.81-92
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• 2023

The purpose of this study is to identify rural research topics, differences in research topics over time, and key mediators through the analysis of academic research trends using topic modeling. This study analyzed a total of 1,183 articles published in the Journal of Rural Planning and Rural Society over a 23-year period (2000-2022). We categorized rural research topics into 30, examined the proportion of research in each topic, and identified major changes in research topics over time. We also identified key words that mediate between research topics. The study found that, first, rural research trends can be categorized into five types (resources and utilization, area/space, people, ecosystem/environment, and tourism), with area/space being the most studied. Subtopics include rural amenities, rural disappearance/village miniaturization, and rural landscape management. Second, the research topics for each period were different. In the first period(2003-2007), the main research topics were rural amenities and Agricultural production- based climate vulnerability assessment. In the second period(2008-2012), the main research topics were Rural extinction and village depopulation, and rural landscape management, and in the third period(2013-2017), the main research topics were rural sixth industrialization and rural ecotourism. In the fourth period(2018-2022), rural development planning and rural life services(life SOC) were the main research topics. The significance of this study is that it extends the existing method of analyzing research trends and provides basic data to enhance comprehensive insights and understanding of rural research.

• 상하수도학회지
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• 제18권6호
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• pp.758-769
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• 2004

The trends and seasonalities of most time series have a large variability. The result of the Singular Spectrum Analysis(SSA) processing is a decomposition of the time series into several components, which can often be identified as trends, seasonalities and other oscillatory series, or noise components. Generally, forecasting by the SSA method should be applied to time series governed (may be approximately) by linear recurrent formulae(LRF). This study examined forecasting ability of SSA-LRF model. These methods are applied to daily water demand data. These models indicate that most cases have good ability of forecasting to some extent by considering statistical and visual assessment, in particular forecasting validity shows good results during 15 days.

• 전기학회논문지
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• 제66권4호
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• pp.613-620
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• 2017

The power grid has been changed to a smart grid system to satisfy the growing need for power grid complexity, demand, reliability, security, and efficiency with a combination of existing power and ICT technology. This study analyzes the research trends in smart grid technology in the period since the introduction of the smart grid system and compares it with industrial trends to grasp the progress and characteristics of Smart Grid technology and look for ways to innovate the technology. To do this, we analyze the research trends using dynamic topic modeling, which is capable of time-series research topic analysis. Next, we compare the results of research trends with industrial trends analyzed by Gartner's experts to demonstrate that smart grid research is evolving to the level of industrialization. The results of this study are quantitative analysis through data mining, and it is expected that it will be used in many fields such as companies that want to participate in industry and government agencies that need to establish policies by showing more objective analysis results.

• 한국전자통신학회논문지
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• 제7권6호
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• pp.1343-1351
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• 2012

본 연구에서는 디스플레이 기술군을 이루는 LED(Light Emitting Diode), OLED(Organic Light Emitting Diode), LCD(Liquid Crystal Display), PDP(Plasma Display Panel), CRT(Cathode Ray Tube) 등 5개의 연구영역에 대하여 과학계량학 기법을 이용하여 트렌드를 살펴보았다. 해당 연구영역별로 Scopus 데이터베이스 논문과 미국특허청(USPTO) 특허데이터베이스의 특허를 이용하여 각각에 대한 인용데이터를 추출하였다. 논문과 특허의 생산건수와 인용데이터를 이용하여 시간의 흐름에 따른 5개 연구영역의 발전과정 및 현재의 관심도를 분석하고 미래의 트렌드를 전망하였다.

• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.1-6
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• 2011

As large-scale building projects have recently increased for the residential, commercial and office facilities, construction costs for these projects have become a matter of great concern, due to their significant construction cost implications, as well as unpredictable market conditions and fluctuations in the rate of inflation during the projects' long-term construction periods. In particular, recent volatile fluctuations of construction material prices fueled such problems as cost forecasting. This research develops a time series model using the Box-Jenkins approach and material price time series data in Korea in order to forecast trends in the unit prices of required materials. Building information modeling (BIM) approaches are also used to analyze injection times of construction resources and to conduct quantity take-off so that total material prices can be forecast. To determine an optimal time series model for forecasting price trends, comparative analysis of predictability of tentative autoregressive integrated moving average (ARIMA) models is conducted. The proposed BIM-based time series forecasting model can help to deal with sudden changes in economic conditions by estimating material prices that correspond to resource injection times.

• 보건교육건강증진학회지
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• 제29권1호
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• pp.13-25
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• 2012

Objectives: The aim of this study was to measure secular trends in health risk behaviors among middle and high school students in Korea between 2005 and 2009 by using data from the Korea Youth Risk Behavior Web-based Survey(KYRBS). Methods: The analyses were performed using data from the 2005, 2006, 2007, 2008, and 2009 KYRBS, which included a nationally representative sample of middle and high school students. A total of 34 health behavior indices were used for the assessment of secular trends in health risk behaviors. Logistic regression models were used to identify statistically significant secular trends in health risk behaviors, after adjusting for gender and grade. Linear and higher-order time variables were simultaneously entered into the statistical models. Results: There was evidence of small, but statistically significant increasing or decreasing trends in certain health risk behaviors. Secular trends in health risk behaviors varied by gender. Conclusions: This study indicates that between 2005 and 2009, changes in health risk behaviors among Korean adolescents were generally small, but represented statistically significant increases or decreases. Further research should explore why certain health risk behaviors are increasing or decreasing and what types of interventions are most effective.

• 산업경영시스템학회지
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• 제42권4호
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• pp.153-164
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• 2019

Since the appearance of smartphones, the smartphone market has been in fierce completion by new technologies and marketing trends. The smartphone market is now somewhat saturated, and the manufacturers are trying to improve their position in the market through the repurchase of existing customers and the influx of competitors. At the same time, customers have their own purchasing criteria for smartphones. Therefore, manufacturers need to determine new technology and marketing trends based on customer purchasing trends and usage characteristics. The aim of this study is to analyze the quality attributes of smartphones. We conducted a survey on 220 respondents, and divided the respondents into several groups by purchasing trends and usage characteristic through cluster analysis. The groups are analyzed and compared based on the Kano model for the quality attributes of smartphone. The analysis result are as follows. Firstly, purchasing trends divide responders into groups that prefers high-end premium smartphones and those that take into account practicality in terms of purchasing trends. Secondly, usage characteristic divide responders into three groups: those with clear usage pattern, those who prefer ease of use, and the rest, and we find out that those with clear usage pattern are important customer in viral marketing. Lastly, Kano analysis is revealed the 'Slow/hi-speed camera', 'Private mode', 'Widget', 'Health care' are attractive quality attributes.

• 대기
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• 제16권4호
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• pp.333-342
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• 2006

The long-term trends of global solar irradiance, air temperature, specific humidity and cloudiness measured at King Sejong station, Antarctica, during the period of 1988-2004, have been investigated. A statistically insignificant decrease, -0.21 $Wm^{-2}yr^{-1}$ (-0.26 %$yr^{-1}$, P<0.5) in global solar irradiance was found in an analysis from the time series of the monthly mean values, except for the increasing trends only in two months of January and June. The trends in irradiance are directly and inversely associated with the cloudiness trends in annual and monthly means. The trends in surface air temperature show a slight warming, $0.03^{\circ}Cyr^{-1}$ (1.88 %$yr^{-1}$, P<0.5) on the annual average, with cooling trend in the summer months and the warming in the winter. The exact relationship, if any, between the irradiance and temperature trends is not known. No significant tendency was found in specific humidity for the same periods. Recent (1996-2004) erythermal ultraviolet irradiance shows decreasing trend in annual mean, -0.15 $mWm^{-2}yr^{-1}$ (-1.18 %$yr^{-1}$, P<0.1) which is about five times the trends of global solar irradiance. The ratio of erythermal ultraviolet to global solar irradiance shows remarkable seasonal variations with annual mean value of 0.01 % and a peak in October and November, showing the increase of ultraviolet irradiance resulting from the Antarctic ozone hole. The sensitivity of global solar irradiance to the change in cloudiness is roughly $13%oktas^{-1}$ which is about twice of the value at the South Pole due to the difference in the average surface reflectance between the two stations. Much more sensitive values of $59%oktas^{-1}$ was found for erythermal UV irradiance than for the global solar irradiance.