• 대한원격탐사학회지
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• 제26권6호
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• pp.665-673
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• 2010

The role of remote sensing in phenological studies is increasingly regarded as a key in understanding large area seasonal phenomena. This paper describes the application of Moderate Resolution Imaging Spectroradiometer (MODIS) time series data for vegetation classification using seasonal variation patterns. The vegetation seasonal variation phase of Seoul and provinces in Korea was inferred using 8 day composite MODIS NDVI (Normalized Difference Vegetation Index) dataset of 2006. The seasonal vegetation classification approach is performed with reclassification of 4 categories as urban, crop land, broad-leaf and needle-leaf forest area. The BISE (Best Index Slope Extraction) filtering algorithm was applied for a smoothing processing of MODIS NDVI time series data and fuzzy classification method was used for vegetation classification. The overall accuracy of classification was 77.5% and the kappa coefficient was 0.61%, thus suggesting overall high classification accuracy.

• 대한원격탐사학회지
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• 제19권5호
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• pp.381-392
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• 2003

Multi-temporal approaches using sequential data acquired over multiple years are essential for satisfactory discrimination between many land-cover classes whose signatures exhibit seasonal trends. At any particular time, the response of several classes may be indistinguishable. A harmonic model that can represent seasonal variability is characterized by four components: mean level, frequency, phase and amplitude. The trigonometric components of the harmonic function inherently contain temporal information about changes in land-cover characteristics. Using the estimates which are obtained from sequential images through spectral analysis, seasonal periodicity can be incorporates into multi-temporal classification. The Normalized Difference Vegetation Index (NDVI) was computed for one week composites of the Advanced Very High Resolution Radiometer (AVHRR) imagery over the Korean peninsula for 1996 ～ 2000 using a dynamic technique. Land-cover types were then classified both with the estimated harmonic components using an unsupervised classification approach based on a hierarchical clustering algorithm. The results of the classification using the harmonic components show that the new approach is potentially very effective for identifying land-cover types by the analysis of its multi-temporal behavior.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 춘계학술대회
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• pp.444-447
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• 2022

최근 몇 년 동안 더 깊은 신경망 아키텍처로 인해 컴퓨터 비전 이미지 분류 작업이 더 빠르고 더 좋아졌다. 그러나 대부분의 이미지 분류 작업은 특정 이미지 모양(예: 고양이와 개 구별)을 기반으로 분류하도록 설계되었지만 낮과 밤 또는 사계절과 같은 기간을 구별하도록 훈련된 분류 모델은 많지 않다. 같은 장소의 사계절 이미지를 구분하기 위한 선행 연구는 있는 반면 일반 영상의 계절 분류 연구는 현재 부재한 실정이다. 그래서 본 논문에서는 일반 영상의 계절 분류 문제에 대한 다양한 접근 방식을 제시한다. 간단한 특징 추출부터 합성곱 신경망 구축, 전이 학습에 이르기까지 계절별 이미지 분류를 위한 세 가지 방법을 연구하고 정확도 결과를 비교, 분석하였다.

• 농업과학연구
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• 제38권3호
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• pp.571-581
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• 2011

This study develops a mid-term preceding observation model of radish to complement an existing short-term agricultural observation model. The first purpose of the study is to extend a three seasonal classification(spring, summer, fall) of fruit-vegetables to a four seasonal classification that involves the winter additionally. This allows us to verify the reason for demand and supply unbalance and unstable price of radish. The second purpose is to construct a mid-term preceding observation model that would be used to forecast planted areas, output, monthly shipment and price. To achieve these purposes, several multiple regression models are estimated. A system is consisted of a planted areas equation, a yield equation, monthly shipment distribution equation, and monthly price equation. To calculate output an auxiliary equation is involved in the system and the consumer price index etc are considered as exogenous variables.

• 한국환경복원기술학회지
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• 제6권1호
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• pp.65-70
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• 2003

This research aims to classify wetland types and evaluate functions of a wetland created by abandoned rice paddies. The case study area is Ja-un wetland in Daejeon Metropolitan City. In this study, wetland types were classified based on the basic elements of wetlands such as hydrology, vegetation, and soil conditions. This study was carried out based upon field surveys, drawing maps and publication, and modified-RAM which can evaluate the general functions and conservation values of wetlands. The analysis shows that several types of wetlands were identified, such as Palustrine/ Perennial/ Hydrophytes, Palustrine/ Perennial/ Openwater, Palustrine/ Seasonal/Herbal, Palustrine/ Seasonal/ Shrub and Scrub, Palustrine/ Seasonal/ Hydrophye, and Riparian/ Seasonal/ Shrub and Scrub in the Ja-un wetland. The average level of functions of the wetlands is very "HIGH", and it is recommended that prompt conservation measures should be taken.

• 한국환경복원기술학회지
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• 제5권1호
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• pp.35-50
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• 2002

This study aims to understand wetland distribution and type-specific classification features with a focus on Tumen River downstream in China by adjusting and improving the classification system used in Korea with a reference to international wetland classification systems and their criteria & methods. In this study, wetland types were determined based on hydrology, vegetation, and soil conditions, which are the most basic elements of wetlands. Also, topography analytical map, vegetation analytical map, and soil analytical map for wetland classification were developed and used based on currently available topography map, vegetation map, and soil map. In addition, codes were defined based on topography, location, hydrology, and vegetation. The result shows that, in the Tumen River downstream, wetlands are often found near natural revetment and terrace land & river-bed lakes. In the discovered wetlands, riverine, lacustrine, and inland wetlands were mostly found at system level. Riparian and human-made wetlands were also identified. At a sub-system level, perennial and seasonal wetlands were found to a similar degree. At a class level, perennial open water, herbal plants, and shrubs were mostly found and sandy plain, hydrophytes, and forest tree types were also observed. An overall detailed classification shows that a total of 17 wetland types were found and a large distribution of sand dunes and river-bed lakes, which are scarce in Northeast Asia, indicates that other rare wetland types such as palustrine seasonal sand plain wetland and lacustrine seasonal sand plain wetland may be discovered.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1483-1485
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• 2003

Multitemporal approaches using sequential data acquired over multiple years are essential for satisfactory discrimination between many land cover classes whose signatures exhibit seasonal trends. At any particular time, the response of several classes may be indistinguishable. Using the estimates of periodogram which are obtained from sequential images, the periodicity of the process have been incorporates into multitemporal classification. The Normalized Difference Vegetation Index (NDVI) was computed for seven-day composites of the Advanced Very High Resolution Radiometer (AVHRR) imagery over the Korean peninsula for 1996 - 2000 using a dynamic technique.

• 한국방재학회 논문집
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• 제9권5호
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• pp.103-113
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• 2009

본 연구에서는 관측소의 지리적 위치 및 강수특성(월별, 계절별, 연평균)을 이용하여 강원도의 강수지역을 구분하였다. 강수지역 구분은 기상관측소 66개소(기상관서: 11개소, 자동기상시스템(AWS): 55개소)의 자료를 이용하였으며, 통계적 방법 중 군집 기법인 K-means 방법을 적용하였다. 지역구분 결과, 강수지역은 5개 지역(영동지방 1개 지역 및 영서지방 4개 지역)으로 구분하였다. 계절별 평균강수량은 봄에는 강원도 전체에 유사하게 발생하였으며, 여름에는 영서지방이 높게 나타났으며, 가을과 겨울에는 영동지방이 높게 발생하였다. 연평균 강수량 및 여름철 강수량의 공간분석 결과 강원도 중 일부 지역(미시령 및 대관령일원)은 산악형 강수 특성을 나타냈으나 전반적인 현상은 아닌 것으로 판단되었다. 그러나 보다 정확한 분석을 위해서는 관측소의 고도별 분포가 미흡한 것으로 나타난 관측소의 보완 및 AWS의 자료 확충이 필요할 것으로 판단된다.

• 한국환경복원기술학회지
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• 제8권6호
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• pp.80-91
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• 2005

This research aims to classify wetland types and evaluate functions of a dam lake. The case study area is Boryung lake in Boryung City. In this study was carried out based upon field surveys, drawing maps and publication, and modified-RAM which can evaluate the general functions and conservation values of wetlands. Eight functions of 2-12 variables each are analyzed for assessing the wetland functions. The analysis shows that several types of wetlands were identified, such as Palustrine/ Perennial/ Hydrophytes, Palustrine/ Perennial/ Openwater, Palustrine/ Seasonal/ Herbal, Palustrine/ Seasonal/ Shrub and Scrub, Palustrine/ Seasonal/ Hydrophye, and Riparian/ Seasonal/ Shrub in the Boryung lake. The average level of functions of the wetlands is very "HIGH", and it is recommended that prompt conservation measures should be taken.

• Journal of Plant Biology
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• 제28권2호
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• pp.149-164
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• 1985

충남 보영군 무창포해수욕장 일대의 조간대 해조군집에 대하여, 종조성, 우점종과 수직분포의 계절적 변화, 그리고 현존량을 1981년 봄-겨울에 걸쳐 조사하였다. 조사기간을 통하여 총 64종(남조 1종, 연조 3종, 갈조 19종, 홍조 41종)의 해조류가 관찰되었다. 조사지역의 해조류 군집은 Sargassum thunbergii, Gelidium divaricatum 및 Pelvetia siliquosa로 대표되었다. 한편, Gloiopeltis furcata는 조간대 상일중부에서, Corallina pilulifera는 하부에서 높은 피도를 보였다. 식생자료에 대한 classification (UPGMA)과 ordination(RA) 결과, 대체로 조위의 하중이 인정되는 경향성을 보였으며, 계절에 따른 군집구조의 변동에 대하여 검토하였다. 단위면적당 평균현존량은 57,2~92.8 g-dry/$m^2$의 범위로서, 봄에 낮고 여름에 높았다.