• 제목/요약/키워드: Selection Strategy

검색결과 988건 처리시간 0.031초

국소적 상관계수를 이용한 자동적 디지털 방사선 영상정합 (Automatic Registration of Images for Digital Subtraction Radiography Using Local Correlation)

  • 이원진;허민석;이삼선;최순철;이재성
    • 대한의용생체공학회:의공학회지
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    • 제25권2호
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    • pp.111-117
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    • 2004
  • 현재 치과 방사선 영상에 적용되고 있는 대부분의 영상공제술은 기준점을 이용한 정한에 근거하고 있다. 본 연구에서는 수작업에 의한 기준점 설정 방법을 이용하지 않고 자동적으로 정참을 수행하는 방법을 개발하였다. 두 영상의 기하학적 매칭을 국소적 관심영역(ROI)에 한정시켜서 이 관심영역 간의 상관계수를 비교한다. 두 영역의 상관계수가 최대화되는 affine 또는 perspective 변환 파라미터를 고속의 탐색전략을 이용하여 반복적으로 찾는다. 우선 1/4 스케일 영상에 대하여 근사적인 파라미터를 탐색한 후 다시 원래 영상에 대하여 미세한 매칭이 이루어진다. 개발된 방법은 Gaussian 잡음에 의해 손상된 모의영상을 모의변환을 하지 않은 영상과 동일한 정도의 정확도를 가지고 정합 할 수 있다. 개발된 방법의 perspective 변환을 이용한 정합의 정확도는 수작업에 의한 것보다 17%향상된 결과를 보였다. 결론적으로, 이 방법의 치과 임플란트 영상에의 적용은 거의 실시간으로 자동적이고 잡음에 강인한 정합을 제공한다.

남성의 속옷 추구혜택에 따른 구매행동 (The Effect of Men's Underwear Benefits Sought on Underwear Purchasing Behavior)

  • 이은경;황진숙
    • 한국의상디자인학회지
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    • 제12권4호
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    • pp.15-28
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    • 2010
  • This study was intended to present basic materials for the direction of product planning and marketing strategy to increase the market share of men's underwear. For this purpose, it attempted to classify the groups according to the benefit of pursuing men's underwear and analyze the differences in purchase behavior among the segmented groups. The specific purposes of the study were to investigate the purchase behavior of men's underwear, to segment the consumers into groups according to underwear benefits sought, to investigate the differences in purchase behavior among the groups, and to investigate the differences in demographics among the groups. The questionnaire was distributed to men aged the 20s to the 40s living in Seoul. A total of 297 questionnaires were used for the final analysis. As a result, the following findings were obtained. It was found that 84.8% of the respondents showed there was no favorite underwear brand. They showed the favorite color of translucent color, the favorite style of trunk and brief, the favorite post-processing of silver nano, deo processing, and the favorite material of charcoal. In purchasing men's underwear, the respondents showed a preference for simple image, and the discount store as the place of purchase. The results also showed that there were four groups of underwear benefits sought: sex appeal/individuality, comfort, practicality, and fashion/brand groups. In regard to the group differences, there were significant differences in underwear purchase motives, underwear preferences, store selection criteria, and demographics.

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우리나라 당뇨병의 역학적 규모와 당뇨병 관리현황 파악을 위한 표본설계의 평가 (An Evaluation of Sampling Design for Estimating an Epidemiologic Volume of Diabetes and for Assessing Present Status of Its Control in Korea)

  • 이지성;김재용;백세현;박이병;이준영
    • Journal of Preventive Medicine and Public Health
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    • 제42권2호
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    • pp.135-142
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    • 2009
  • Objectives : An appropriate sampling strategy for estimating an epidemiologic volume of diabetes has been evaluated through a simulation. Methods : We analyzed about 250 million medical insurance claims data submitted to the Health Insurance Review & Assessment Service with diabetes as principal or subsequent diagnoses, more than or equal to once per year, in 2003. The database was re-constructed to a 'patient-hospital profile' that had 3,676,164 cases, and then to a 'patient profile' that consisted of 2,412,082 observations. The patient profile data was then used to test the validity of a proposed sampling frame and methods of sampling to develop diabetic-related epidemiologic indices. Results : Simulation study showed that a use of a stratified two-stage cluster sampling design with a total sample size of 4,000 will provide an estimate of 57.04%(95% prediction range, 49.83 - 64.24%) for a treatment prescription rate of diabetes. The proposed sampling design consists, at first, stratifying the area of the nation into "metropolitan/city/county" and the types of hospital into "tertiary/secondary/primary/clinic" with a proportion of 5:10:10:75. Hospitals were then randomly selected within the strata as a primary sampling unit, followed by a random selection of patients within the hospitals as a secondly sampling unit. The difference between the estimate and the parameter value was projected to be less than 0.3%. Conclusions : The sampling scheme proposed will be applied to a subsequent nationwide field survey not only for estimating the epidemiologic volume of diabetes but also for assessing the present status of nationwide diabetes control.

소 질병 검출을 위한 혈청학적 검사의 민감도 평가 (Sensitivity analysis of serological tests for detection of disease in cattle)

  • 이상진;문운경;박선일
    • 대한수의학회지
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    • 제50권1호
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    • pp.43-48
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    • 2010
  • Animal disease surveillance system, defined as the continuous investigation of a given population to detect the occurrence of disease or infection for control purposes, has been key roles to assess the health status of an animal population and, more recently, in international trade of animal and animal products with regard to risk assessment. Especially, for a system aiming to determine whether or not a disease is present in a population sensitivity of the system should be maintained high enough not to miss an infected animal. Therefore, when planning the implementation of surveillance system a number of factors that affecting surveillance sensitivity should be taken into account. Of these parameters sample size is of important, and different approaches are used to calculate sample size, usually depending on the objective of surveillance systems. The purpose of this study was to evaluate the sensitivity of the current national serological surveillance programs for four selected bovine diseases assuming a specified sampling plan, to examine factors affecting the probability of detection, and to provide sample sizes required for achieving surveillance goal of detecting at least an infection in a given population. Our results showed that, for example, detecting low level of prevalence (0.2% for bovine tuberculosis) requires selection of all animals per typical Korean cattle farm (n = 17), and thus risk-based target surveillance for high risk groups can be an alternative strategy to increase sensitivity while not increasing overall sampling efforts. The minimum sample size required for detecting at least one positive animal was sharply increased as the disease prevalence is low. More importantly, high reliability of prevalence estimation was expected with increased sampling fraction even when zero-infected animal was identified. The effect of sample size is also discussed in terms of the maximum prevalence when zero-infected animals were identified and on the probability of failure to detect an infection. We suggest that for many serological surveillance systems, diagnostic performance of the testing method, sample size, prevalence, population size, and statistical confidence need to be considered to correctly interpret results of the system.

복잡한 의사결정과 협상 환경을 위한 에이전트 기반 시스템: 가상생산 응용 (Agent-based System for Complex Decision Making and Negotiation: Application to Virtual Manufacturing)

  • 이경전;장용식;최형림;김현수;박영재;박병주
    • 경영정보학연구
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    • 제4권2호
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    • pp.223-236
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    • 2002
  • 복잡한 의사결정과 협상 환경을 위한 에이전트 기반 시스템은 환경에 대한 감지 및 반응이라는 간단한 작동방식을 가지는 다중 에이전트 시스템과는 다르게 접근되어야 한다. 본 논문에서는 가상 생산 환경을 응용 분야로 하여 복잡한 의사결정과 협상 환경을 위한 다중에이전트 시스템을 구현하는 과정에서 발생하는 연구이슈를 정리하고, 이들을 해결하는 하나의 사례를 제시한다. 가상 생산 환경은 다수 조직치 존재, 자원제약의 문제, 시간이 제한된 상황에서의 일정 계획 문제 등 복잡한 의사결정과 협상 환경의 전형적인 요소를 가지고 있다. 이 문제를 해결하기 위해서, 본 연구는 시간제약하에서의 외부협상 및 내부협력을 위한 프로토콜을 개발하고, 실세계의 시간제약을 만족하는 범위에서 최적화모형과 휴리 스틱모형을 상황적으로 적응하는 체계를 제시하며, 에이전트간의 소통 메시지를 이들 의사결정모형으로 모형화하는 과정을 예시한다.

아웃소싱 파트너 선정요인과 전략이 아웃소싱 성공도 및 BSC성과에 미치는 영향에 관한 연구 (The effects of outsourcing strategies and outsourcing partner selection factors on the success of outsourcing and BSC performance)

  • 정범성;심정택;이상식
    • 한국산업정보학회논문지
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    • 제18권6호
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    • pp.113-125
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    • 2013
  • 치열한 경쟁환경에서 많은 기업들이 외부의 전문성 활용을 통한 비용절감, 리스크 감소, 경영효율화 추구, 핵심역량의 강화 등을 위해 아웃소싱을 도입하고 있다. 또한, 기업전략 및 기업의 구조적 변혁을 통한 혁신적 활동으로써 아웃소싱을 전략적으로 활용하고 있다. 본 연구의 목적은 우리나라 제조업을 중심으로 아웃소싱 파트너 선정요인과 전략에 따른 아웃소싱 성공도와 BSC 성과간의 영향에 관한 연구를 하였다. 따라서 제조기업의 아웃소싱 전략과 아웃소싱 파트너 선정요인에 따른 성공도를 파악하고 그에 따르는 기업의 성과를 BSC 관점에서 실증분석을 하였다. 본 연구는 제조기업의 아웃소싱 성공도와 기업의 BSC관점에서의 성과에 관한 요인을 파악함으로써 현재 진행 중인 아웃소싱 업체의 평가 및 보상에 관하여 실무적 접근을 가능토록 하였다. 현재 기업의 환경 및 전략 의도에 따라 아웃소싱 파트너 선정과 아웃소싱 전략을 수행함으로써 만족도와 효과에 대한 기대치를 예상할 수 있는데 도움이 될 것이다.

중국의 재료과학분야 연구현황과 우리의 대응방안 (Chinese Research Trends in Materials Science and the Korean Countermeasure)

  • 노경란;길상철;남수우
    • 한국재료학회지
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    • 제23권12호
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    • pp.745-756
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    • 2013
  • Recent rapid development of the Chinese economy based on science and technology is challenging Korean industries and economy. Since the driving force for this rapid development of China is known to be scientific technologies, the purpose of this research is to confirm the current status of Chinese scientific research in the field of "Materials Science and Engineering" and propose a strategy for competition with China. Even though there are numerous journals of "Materials Science and Engineering", the 10 most popular journals with high impact factors were selected to cover general materials, nano materials, bio materials, and electronic materials. It was found that the number of scientific papers written by Chinese scientists for the materials field in the 10 journals was slowly increasing from the year 2000 until 2005, but has been rapidly increasing since 2005. This research found that Chinese research activities in the traditional metallic materials and nano materials have tremendously increased to occupy around 30 % or more papers published in several major journals related with materials science and engineering. On the other hand, bio materials and electronic materials research has not been pursued so actively; however, very recently the number of publications in these fields is also beginning to increase. To compete with this tremendously growing Chinese scientific development, Korea should have a policy of "selection and concentration" in materials-related fields, including basic science in nano, bio, and electronic materials.

Characterization of Novel Trichoderma asperellum Isolates to Select Effective Biocontrol Agents Against Tomato Fusarium Wilt

  • El_Komy, Mahmoud H.;Saleh, Amgad A.;Eranthodi, Anas;Molan, Younes Y.
    • The Plant Pathology Journal
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    • 제31권1호
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    • pp.50-60
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    • 2015
  • The use of novel isolates of Trichoderma with efficient antagonistic capacity against Fusarium oxysporum f. sp. lycopersici (FOL) is a promising alternative strategy to pesticides for tomato wilt management. We evaluated the antagonistic activity of 30 isolates of T. asperellum against 4 different isolates of FOL. The production of extracellular cell wall degrading enzymes of the antagonistic isolates was also measured. The random amplified polymorphic DNA (RAPD) method was applied to assess the genetic variability among the T. asperellum isolates. All of the T. asperellum isolates significantly reduced the mycelial growth of FOL isolates but the amount of growth reduction varied significantly as well. There was a correlation between the antagonistic capacity of T. asperellum isolates towards FOL and their lytic enzyme production. Isolates showing high levels of chitinase and ${\beta}$-1,3-glucanase activities strongly inhibited the growth of FOL isolates. RAPD analysis showed a high level of genetic variation among T. asperellum isolates. The UPGMA dendrogram revealed that T. asperellum isolates could not be grouped by their antagonistic behavior or lytic enzymes production. Six isolates of T. asperellum were highly antagonistic towards FOL and potentially could be used in commercial agriculture to control tomato wilt. Our results are consistent with the conclusion that understanding the genetic variation within Trichoderma isolates and their biochemical capabilities are required for the selection of effective indigenous fungal strains for the use as biocontrol agents.

방사성 폐기물 지층 처분장과 암반의 역학적 특성 변화 - ANDRA의 예 - (Mechanical evolution of radioactive waste repository and rock mass - A review on ANDRA's case -)

  • 정소걸;신중호
    • 터널과지하공간
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    • 제18권3호
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    • pp.165-174
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    • 2008
  • 지하 500 m의 처분장 주위 암반이 수 십 만년 이상 장기적으로 지압과 열하중을 받음으로 인해 발생되는 역학적-열적-수리적-화학적 특성변화에 대한 프랑스의 연구 결과를 분석하고 우리나라의 방사성 폐기물 처분에 관련된 연구 방향 설정과 부지확보 등 기초자료를 도출하고자 하였다. 우리나라에서 방사성 폐기물 관련 사업을 수행함에 있어 선택의 폭을 넓히기 위해서는 첫째, 처분심도를 비롯한 처분 대상 지질매체(화성암 및 퇴적암)의 결정을 위한 데이터베이스의 구축이 시급하며, 특히 처분장 건설시에 갱도 혹은 처분 셀 주위에 발생되었던 파쇄 균열이 처분장을 장기간 운영하는 과정에서 치료되는 특성에 대한 규명이 필요할 것이다. 둘째, 장기적 EDZ 거동 변화에 대한 검증이 필요하며 처분 개념의 가역성(reversibility)에 대한 검토도 이루어져야 할 것으로 판단된다. 셋째, 한국형 방사성 폐기물 지층처분에 관한 타당성 검토와 개념설계를 바탕으로 구축된 지하실험실을 이용하여 처분장 설계 개념을 검증하는 연구 개발이 시급한 것으로 판단된다.

고등학교(高等學校) 학생(學生)의 대수(代數) 문제(問題) 해결(解決) : 전략(戰略)과 오류(誤謬) 분석(分析) (Algebraic Problem Solving of the High School Students : An Analysis of Strategies and Errors)

  • 이상원;전평국
    • 한국수학교육학회지시리즈E:수학교육논문집
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    • 제2권
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    • pp.181-191
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    • 1997
  • The purpose of this study is to provide the primary sources to improve the problem solving performance by analyzing the errors and the strategies selection of the high school students when solving given algebraic problems. To attain the purpose of this study, the questions for investigation in this study are : 1. What are the differences / similarities in the patterns of errors committed by successful and unsuccessful problem-solvers when solving particular algebraic problems ? 2. What are the error types chosen by unsuccessful problem-solvers when solving particular algebraic problems? 3. Do students utilize checking, either locally or globally, when solving particular algebraic problems? Twenty students were drawn out of 10th grade students in J girls' high school in Yengi -gun, Chung-Nam, for this study. The problem-solving test was used as a test instrument. From the data, the verbal protocols and the written protocols were analyzed by the patterns. The conclusions drawn from the results obtained in the present study are as follows: First, in solving particular algebraic problems, when the problems were solved with one strategy, most students didn't give any consideration to other strategies. So mathematics teachers should teach them to use the various strategies, and should develop the problems to be used the various strategies. Second, in solving particular algebraic problems, errors on notions or transformations of equations were found. Thus, the basic knowledges related to equation should be taught. In addition, most unsuccessful students seleted the strategies inadequately to solve the problems because of misunderstanding the problems. So, to improve the problem solving performance the processes of 'understanding problem' should be emphasized to students. Third, although the unsuccesful students used the 'checking' processes when solving the problems, most of them did not find the errors because of misconceptions related to the problems, carelessness, and unskillfulness of checking. Thus, students must be taught more carefully and encouraged to use the checking.

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