• 품질경영학회지
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• 제36권1호
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• pp.31-39
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• 2008

This paper proposes a method of estimating the lifetime distribution at use condition for constant stress accelerated life tests when an infant-mortality failure mode as well as wear-out one exists. General limited failure population model is introduced to describe these failure modes. It is assumed that the log lifetime of each failure mode follows a location-scale distribution and a linear relation exists between the location parameter and the stress. An estimation procedure using the expectation and maximization algorithm is proposed. Specific formulas for Weibull distribution are obtained. An illustrative example and the simulation results are given.

• 한국정보처리학회논문지
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• 제6권10호
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• pp.2728-2739
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• 1999

This paper proposes an effective fusion algorithm for retrieval results from heterogeneous information sources in federated digital libraries. The algorithm determines the population of documents retrieved from involved information sources for a given query and evaluates the degree of relevance between the query and the population. The evaluated results are used as relevance distribution information for collection fusion. The main informations used for the fusion are relevance distribution among collections, the population size N, and ranking information of relevant documents in their origin. We also present th performance evaluation of the algorithm by developing the prototype of a meta-searcher.

• 한국IT서비스학회지
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• 제18권1호
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• pp.131-140
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• 2019

This study compares and analyzes the spatial distribution of people in two cities using location information in twitter data. The target cities were selected as Paris, a traditional tourist city, and Dubai, a tourist city that has recently attracted attention. The data was collected over 123 days in 2016 and 125 days in 2018. We compared the spatial distribution of two cities according to the two periods and residence status. In this study, we have found a hot place using a spatial statistical model called dart-shaped space division and estimated the urban area by reflecting the distribution of tweet population. And we visualized it as a CDF (cumulative distribution function) curve so that the distance between all the tweets' occurrence points and the city center point can be compared for different cities.

• Journal of Ecology and Environment
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• 제37권2호
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• pp.99-104
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• 2014

We estimated the influence of environmental factors on zooplankton communities at 25 reservoirs during winter (December 2010 to January 2011). Among zooplankton groups, Cyclops vicinus is more dominant during winter, and this is positively related to withered vegetation area and dissolved oxygen level. Therefore, the presence of withered vegetation might be considered as an important factor to determine C. vicinus distribution during winter. We considered that withered vegetation might be utilized as a habitat for C. vicinus, as well as provide an attachment substrate for periphytic algae. Abundance of periphytic algae can lead to high concentration of dissolved oxygen. Although copepods prefer high water temperatures for increasing their population growth, if Cyclops can overcome low temperature stress that leads to disruption of population, their population growth initiation in the next growing season (i.e. next spring) is possibly propelled by the winter population.

• 한국환경복원기술학회지
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• 제24권5호
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• pp.25-34
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• 2021

Increase in avian species richness is one of the important issues of urban biodiversity policies, since it can promote diverse ecosystem services such as seed dispersal, education, and pollination. However, though human disturbance can significantly affect avian species richness, there are limited studies on the way to reflect the dynamics of floating population. Therefore, this study analyzed the spatial relationship between avian species richness, floating population, and vegetation cover using telecommunications information to identify the areas that requiring targeted monitoring and restoration action. Bivariate Local Moran's I was applied to identify LISA cluster map that showing representative biotopes, which reflect significant spatial relationship between species richness and population distribution. Edge density and distribution of ndvi were identified for evaluating relative adequacy of selected biotopes to strengthen the robust biodiversity network. This study offers insight to consider human disturbance in spatial context using innovative big data to increase the effectiveness of urban biodiversity measures.

• Animal Systematics, Evolution and Diversity
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• 제32권2호
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• pp.105-111
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• 2016

The genetic structure of marine animals that inhabit the seashore is affected by numerous factors. Of these, gene flow and natural selection during recruitment have strong influences on the genetic structure of seashore-dwelling species that have larval periods. Relative contributions of these two factors to the genetic structure of marine species would be determined mainly by the duration of larval stage. The relationship between larval period and genetic structure of population has been rarely studied in Korea. In this study, genetic variations of cytochrome oxidase subunit I (COI) were analyzed in two dominant species on rocky shore habitats in the Korean peninsula: periwinkle Littorina brevicula and acorn barnacle Fistulobalanus albicostatus. Both species are not strongly structured and may have experienced recent population expansion. Unlike periwinkle, however, barnacle populations have considerable genetic variation, and show a bimodal pattern of mismatch distribution. These results suggest that barnacle populations are more affected by local adaptation rather than gene flow via larval migration. The bimodal patterns of barnacle populations observed in mismatch distribution plots imply that they may have experienced secondary contact. Further studies on seashore-dwelling species are expected to be useful in understanding the evolution of the coastal ecosystem around Korean waters.

• 한국지리정보학회지
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• 제23권3호
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• pp.68-84
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• 2020

본 연구에서는 경상남도 창원시를 대상으로 노인인구 분포지역의 공간적 특성과 폭염과의 관계를 분석하였다. 이를 위해 통계청의 인구센서스 자료와 환경부 토지피복도, Landsat 8 지표면온도, 기상청의 폭염일수 자료를 활용하였다. 노인인구 분포의 공간적 특성은 토지이용특성을 고려하여 K-mean 군집화 분석을 통해 총 5개 유형으로 분류하였다. 공간유형별 노인인구 특성은 도시화된 유형(cluster-3)에서 노인인구의 수가 많았으나, 농촌지역과 산림지역에 분포하는 유형(cluster-1, cluster-2)에서는 노인인구의 구성 비율이 높은 것으로 나타났다. 지표면온도와 폭염일수 특성에서는 도시지역에서 지표면온도가 가장 높았으나 폭염일수는 농촌지역이 가장 많았다. 노인인구 분포지역의 공간유형에 따른 폭염 특성을 분석한 결과, 농촌지역 면적이 많은 cluster-2가 15.95일로 가장 높았고, 도시화된 유형인 cluster-3은 9.41일로 가장 낮았다. 즉, 도시지역에 거주하는 노인인구보다 농촌지역에 거주하는 노인인구가 폭염에 더욱 노출되어 있으며, 피해가 가중될 것으로 예상된다. 본 연구의 결과는 여름철 폭염 취약지역의 효과적인 관리와 사전 예방을 위한 다양한 정책방안을 마련하는데 기초적인 자료로 활용될 수 있을 것이다.

• 한국경제지리학회지
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• 제22권3호
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• pp.351-365
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• 2019

본 연구의 목적은 주요 이동요인별 인구이동 및 인구분포의 시공간적 특징을 분석하고 장래 지역별 인구분포의 변화를 예측하고 전망하는 것이다. 이를 위해 직업, 가족, 주택, 교육 등 주요 이동요인별 거주지 변화로 나타나는 지역별 인구이동의 추이를 파악하고, 장래 지역별 인구 유출입에 의한 인구분포의 변화를 추정하는 예측 시뮬레이션을 진행한다. 분석결과, 거주지를 변경함에 있어 대도시지역과 시 단위 중심의 지리적 이동이 나타나고 있으며 대도시와 시 단위 내에서도 지역별 인구 유출입에 영향을 미치는 주요 이동요인별 구성 비율은 각기 상이하게 나타난다. 또한 이동요인별 시군구별 추이확률과 상태확률을 토대로 6단계-정상 마르코프 연쇄 프로세스를 진행한 결과, 각 이동요인에 따라 장래 시군구별 인구분포의 변화 정도도 차이가 나타날 것으로 추정된다. 본 연구에서 제시하는 방법론과 분석결과는 특히 인구감소로 지방소멸이 우려되는 지역에서 인구의 유입요인은 강화하고 유출요인은 개선하는 지역 맞춤형 인구 및 각종 정책을 계획하고 마련하는데 활용될 수 있다.

• 유통과학연구
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• 제3권2호
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• pp.15-28
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• 2005

본 연구는 소비자 니즈의 변화에 따른 식품컨셉의 변형으로 인한 일본의 식품유통시스템의 발전과정을 살펴보는 것을 연구의 목적으로 한다. 본 논문에서는 식품컨셉으로서 일반적으로 가공식품과 비가공식품으로 분류되었던 식품컨셉을 확장시켜 비가공적 가공식품과 가공적 비가공식품의 개념을 소개하고, 그에 따른 일본식품유통시스템의 물류, 도매, 소매상에서의 혁신적 관리 및 발전과정을 살펴본다. 일본 식품유통시스템의 변화에 근본적인 원인을 제공한 요인으로서 소비자 니즈와 인식의 변화를 들 수 있으며, 일본 식품유통시스템의 개념정립 및 현황분석과 함께 일본 식품유통시스템의 실제적 변화로서 온도대별 물류혁신, PB상품개발, 체인시스템의 다양화 등을 살펴보기로 한다. 이와 같은 일본소비자의 특성, 식품유통시스템의 발전상황 및 사례를 연구함으로써 한국식품유통시스템의 발전과정과 비교분석이 가능하며 나아가 합리적인 식품유통시스템으로의 방향제시가 가능하다고 사료된다.

• 보건행정학회지
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• 제3권2호
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• pp.81-99
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• 1993

The purpose of this research is to assess the geographical distribution of physicians and dentists and the degree of maldistribution of the physician. Data were obtained form the Korean Medical Association's report on physicians registry and census for 1990. To assess the degree of disparity in the rural-urban distribution of physician manpower and to identify changes in the distribution pattern, the Gini index of concentration was used. Major findings are as follows; 1. Urban-rural disparity in the distribution of physician manpower exists in all categories of manpower, i.e. physician, dentist, oriental medical doctor, general practitioner, medical specialist, practitioner, public health physician and public health dentist. Urban area which had 74.4% of nation's population, accounted for over 90% of all physician manpower. 2. In terms of the ration of physician manpower per 10, 000 population, in urban area, they were 8.2 physicians, 2.7 general practitioners, 5.5 specialists, 3.0 practitioners, 1.8 dentists and 1.3 oriental medical doctors. In rural area, the ratios were 1.4 physicians, 0.6 general practitioners, 0.9 specialists, 1.0 practitioners, 0.4 dentists and 0.4 oriental medical doctors. 3. Gini indicies computed to measure inequality of physician manpower distribution were 0. 3675 for physicians, 0.3372 for general practitioners, 0.3338 for specialists, 0.2263 for practitioners, 0.3132 for dentists and 0.3293 for oriental medical doctors. 4. Inspite of increase in the number of physician manpower, urban concentration of physician manpower intensified from 1980 to 1990. However, the Gini index for all physician manpower fell by 18.3~36.7% from 1980 to 1990, indicating more even distribution. 5. In rural area, the public health physicians and dentists had increased the ratios of physicians, general practitioners, practitioners and dentists per 10, 000 population remarkebly, and had decreased the Gini indicies of physicians, general practitioners, practitioners and dentists. Thus, public health physicians and dentists contributed to improve the distribution of physician manpower in rural area. Based on the results of this study, long-term and rational manpower policies should be developed to solve the problem of geographical maldistribution of physician manpower as well as short-term policy for inducing physicians to the rural areas.