• 대한원격탐사학회지
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• 제37권2호
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• pp.199-209
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• 2021

장기적인 시계열 수량 평균이 기술적인 발전 요인에 의해 증가하는 추세를 제거하여, 기존 MODIS NDVI 및 기상자료를 이용한 우리나라 벼 수량 추정 모형을 개선하고자 하였다. 이를 위해 2002년부터 2019년 까지의 NDVI (MYD13Q1)와 기상자료를 사용하여 다중 선형 회귀 분석을 수행하였다. 벼 수량 추세를 분석하고 이를 제거하여 모형을 보완하였다. 개선된 모형을 이용하여 추정한 벼 수량과 수량 통계 값 간의 상관 분석을 통해 추세 제거에 따른 정확도를 평가하였다. 그 결과, 추세가 제거된 벼 수량 추정 모형에 의해 예측된 수량이 통계 수량의 연간 변동 특성을 잘 반영하고 있는 것으로 나타났다. 추세 제거 전의 모형과 비교하여 통계 수량과의 상관계수와 결정계수도 높게 나타났다. 따라서 추세 제거 방법이 벼 수량 추정 모형을 효과적으로 보정하는 방법임을 확인하였다.

• 대한공간정보학회지
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• 제20권1호
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• pp.93-99
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• 2012

본 연구는 행정중심복합도시 건설에 따라 이에 편입되는 지역과 그 주변지역을 포함한 공주시를 대상으로 지가의 시공간적 변화패턴을 파악하는데 목적이 있다. 이를 위해 2000년, 2005년, 2010년을 기준시점으로 209개의 동/리별 평균지가를 산출하여 GIS데이터를 구축하였다. 분석방법으로는 크게 3가지 측면으로 구분할 수 있다. 먼저 공간통계기법의 일종인 크리깅 보간에 의한 5년 단위의 지가변화 추이를 파악하였다. 둘째, 동서축과 남북축의 방향별 변화패턴을 알아보기 위해 경향분석(trend analysis)을 실시하였다. 셋째, 시점별 지가중심점의 이동 방향을 살펴보기 위해 지가를 가중치로 하여 가중평균중심점(weighted mean center)을 산출하였다. 그 결과 지목(Land Category)별 지가변화추세는 행정중심복합도시에 편입되는 동부지역에서 높은 성장세를 보이는 것으로 나타났고, 중심점의 이동방향 역시 동북부지역으로 편중되는 현상을 보였다.

• 한국수자원학회논문집
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• 제42권11호
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• pp.933-951
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• 2009

지구온난화에 따른 기후변화가 우리나라의 물순환 과정에 영향을 미칠 수 있다. 강우는 여러 기상인자들과 복잡한 영향을 주고 받으며 발생한다. 따라서 강우는 물순환 과정에서 기후변화에 따른 영향을 크게 받는 인자 중의 하나이다. 본 연구에서는 강우특성을 나타낼 수 있는 여러 시계열 자료를 구축하였다. 또한 강우의 발생 시계열을 연별, 계절별 및 월별로 구성하여 분석하였다. 분석 방법은 시계열 자료의 평균과 표준편차의 변동성 분석과 경향성 분석을 수행하였다. 또한, 최근 10년 동안에 강우특성의 변화에 대한 상대오차를 계산하여 과거 자료들과 비교하였다. 분석 결과에서 강우자료의 고유 특성인 무작위성에 의하여 뚜렷한 통계적 결과는 나타나지 않았다. 그러나 일반적으로 최근 10년간 강우량은 증가하였으며, 강우일수는 감소하는 추세를 보였다. 또한, 계절별과 월별에 따른 강우특성의 변화가 다르게 나타나고 있음을 확인할 수 있다.

• 대기
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• 제33권1호
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• pp.1-20
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• 2023

Holding the longest observation data from April 1904, Busan is one of the essential points to understand the climate variability of the Korean Peninsula without missing data since implementing the modern weather observation of the South Korea. Busan is featured by coastal areas and affected by various climate factors and fluctuations. This study aims to investigate climate variability and changes in climatic variables, extremes, and several weather indexes. The statistically significant change points in daily mean rainfall intensity and temperature were found in 1964 and 1965. Based on the change point detection, 117 years were divided into two periods for daily mean rainfall intensity and temperature, respectively. In the long-term temperature analysis of Busan, the increasing trend of the daily maximum temperature during the period of 1965~2021 was larger than the daily mean temperature and the daily minimum temperature. Applying Ensemble Empirical Mode Decomposition, daily maximum temperature is largely affected by the decadal variability compared to the daily mean and minimum temperature. In addition, the trend of daily precipitation intensity from 1964~2021 shows a value of about 0.50 mm day^-1, suggesting that the rainfall intensity has increased compared to the preceding period. The results in extremes analysis demonstrate that return values of both extreme temperatures and precipitation show higher values in the latter than in the former period, indicating that the intensity of the current extreme phenomenon increases. For Wet-Bulb Globe Temperature (effective humidity), increasing (decreasing) trend is significant in Busan with the second (third)-largest change among four stations.

• 한국정보과학회논문지:소프트웨어및응용
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• 제36권3호
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• pp.236-243
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• 2009

특허, 뉴스, 블로그와 같이 시간 정보가 있는 문서들로부터의 자동적인 트렌드 분석(trend analysis)은 토픽탐지 및 추적 기술(TDT: Topic Detection and Tracking)과 더불어 중요한 연구 분야로 대두되고 있다. 과거 연구들은 대부분 트렌드과 관련된 단어의 출현 빈도 정보를 이용하여 주어진 개념의 중요도를 측정하고 이 개념의 시간에 따른 트렌드 라인을 보여주는 것에 초점을 맞췄다. 신출 트렌드 (emerging trend)를 탐지하기 위해서는 주어진 개념의 출현 빈도수 변화와 같은 간단한 방법이나 학습 데이타와 비교하여 차이를 탐지하여 제시하는 방법이 사용되었다. 그러나 여러 트렌드 중에서 특징적인 트렌드를 찾아서 사용자에게 제공하기 위해서는 트렌드 순위 결정 함수가 필요하다. 본 논문은 트렌드의 다양한 측면을 정량화하기 위하여 출현 빈도로 구성된 트렌드 곡선으로부터 네 가지 속성 (변동성, 지속성, 안정성, 누적량) 을 정의하고 이를 활용한 트렌드 순위 결정 방법을 제안한다. 일련의 실험을 통하여 각 속성의 유용성을 검증하고 속성들의 조합이 순위 결정에 어떤 영향을 미치는지 분석하였다. 실험결과로부터 네 가지 속성을 모두 조합할 경우 특징적인 트렌드 탐지에 더욱 기여하는 것을 알 수 있다.

• Asian Pacific Journal of Cancer Prevention
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• 제17권5호
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• pp.2513-2518
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• 2016

Background: In 2008, non-Hodgkin lymphoma ranked tenth among other malignancies worldwide with an incidence of around 5 cases per 100,000 in both genders. The latest available rates in Tunisia are from 2006. Materials and Methods: This study aimed to provide an update about NHL incidence for 2009 and its trend between 1998 and 2009 as well as a projection until 2024, using data from the Salah Azaiz Institute hospital registry and the Noth Tunisia cancer registry. Results: In 2009, the NHL incidence in the north of Tunisia was 4.03 cases per 100,000, 4.97 for men and 3.10 for women. Diffuse large B-cell lymphoma (DLBCL) accounted for 63.2% of all NHL subtypes. Between 1998 and 2009, the overall trend showed no significant change. When we compared the trend between two periods (1998-2005 and 2005-2009), joinpoint regression showed a significant decrease of NHL incidence in the first period with an annual percentage change (APC) of -6.7% (95% CI:[-11.2%;-2%]), then the incidence significantly increased from 2005 to 2009 with an APC of 30.5% (95% CI: [16.1%; 46.6%]. The analyses of the different subtype trends showed a significant decrease in DLBCL incidence between 1998 and 2000 (APC:-21.5; 95% CI: [-31.4%;-10.2%]) then the incidence significantly increased between 2004 and 2007 (APC: 18.5; 95% CI: [3,6%;35.5%]). Joint point analysis of the age-period-cohort model projection showed a significant increase between 2002 and 2024 with an APC of 4.5% (%95 CI: [1.5%; 7.5%]). The estimated ASR for 2024 was 4.55/100 000 (95% CI: [3.37; 6.15]). Conclusions: This study revealed an overall steady trend in the incidence of NHL in northern Tunisia between 1998 and 2009. Projection showed an increase in the incidence in NHL in both genders which draw the attention to the national and worldwide burden of this malignancy.

• Asian Pacific Journal of Cancer Prevention
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• 제17권3호
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• pp.1393-1397
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• 2016

Background: Breast cancer is the most common cancer and the first cause of cancer death in women worldwide, with infiltrating duct carcinoma as the most common morphology. This study aimed to investigate trend of breast cancer incidence by age groups and histological changes in Iranian women between 2003 and 2008. Materials and Methods: This is analytic study, carried out based on re-analysis of the Cancer Registry Center report of health deputy for women's breast cancer in Iran during a 6-year period (2003-2008). Statistical analysis for incidence time trends and morphology change percentage carried out joinpoint regression analysis using the software Joinpoint Regression Program. Results: A total of 36,340 cases were reported for Iranian women in the six years. Analytical trend showed an increasing incidence trend with significant annual percentage change (APC) of 15.2 (CI: 11.6 to 18.8). The lowest and highest significant increased trend were related to age groups of 40 to 44 years and above 85 years, respectively; with APCs of 13.0 and 25.1, respectively. Of total cases, 78.7% of cases were infiltrating duct carcinoma, decreasing from 82.0% in 2003 to 76.6% in 2008, which was significant with an APC equal to -1.76 (CI:-2.7 to -0.8). Conclusions: The incidence trend of breast cancer is rising in Iranian women. The highest incidence was observed in the age groups 45-65 and 80-85. In conclusion, to reduce breast cancer incidence and its burden, preventive and screening programs for breast cancer, especially in young women, are recommended in Iran.

• 상하수도학회지
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• 제23권2호
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• pp.241-249
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• 2009

It is well known that the trend of water demand in large-size water supply systems has been suddenly changed, and many expansions of water supply facilities become unnecessary. To be cost-effective, thus, politicians as well as many professionals lay stress on the adaptive management of water supply facilities. Failure in adapting to the new trend of demand is sure to be the most critical reason of unnecessary expansions. Hence, we try to develop the model and modeling procedure that do not depend on the old data of demand, and provide engineers with the fast learning process. To forecast water demand of Seoul, the Bayesian parameter estimation was applied, which is a representative method for statistical pattern recognition. It results that we can get a useful time-series model after observing water demand during 6 years, although trend of water demand were suddenly changed.

• 한국디지털건축인테리어학회논문집
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• 제12권1호
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• pp.89-98
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• 2012

While the housing transaction price of Seoul tends to be stagnant or declining in line with the housing market recession since 2007, the jeonse price keeps continual increase. Such flow of jeonse price change has a serious influence on ordinary person's housing stability seriously. Therefore, it is very meaningful in terms of social policy to analyze the trend of recent jeonse price change. This study aims to have an empirical analysis of structural characteristics of the trend of recent jeonse price change. After the review of various previous studies, this study selected housing jeonse price index, non-sold house quantity, jeonse vs. transaction price rate, and housing construction performance as analytical variables, and employed monthly time series resources from January 2007 to April 2011. As a result, when the housing supply reduced, the potential quantity for jeonse market reduced that occurred unbalance of supply and demand in jeonse market. In turn, it caused the increase of jeonse price. And, in case of jeonse vs. transaction price rate change, the rate increased which means the increase of required rate of return of invested demand. As such, the increase of market risk degenerates the investment sentiment which caused the reduction of quantity for jeonse market as a submarket.

• 한국농공학회논문집
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• 제57권5호
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• pp.69-80
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• 2015

The majority of projections of future climate come from Global Circulation Models (GCMs), which vary in the way they were modeled the climate system, and so it produces different projections about conceptualizing of the weather system. To implement climate change impact assessment, it is necessary to analyze trends of various GCMs and select appropriate GCM. In this study, climate data in 25 GCMs 41 outputs provided by Coupled Model Intercomparison Project Phase 5 (CMIP5) was downscaled at eight stations. From preliminary analysis of variations in projected temperature, precipitation and evapotranspiration, five GCM outputs were identified as candidates for the climate change impact analysis as they cover wide ranges of the variations. Also, GCM outputs are compared with trends of HadGCM3-RA, which are established by the Korean Meteorological Administration. From the results, it can contribute to select appropriate GCMs and to obtain reasonable results for the assessment of climate change.