• 제목/요약/키워드: Depth of focus

검색결과 823건 처리시간 0.023초

홍채 영상 초점 값에 기반한 홍채 영상 복원 연구 (A Study on Iris Image Restoration Based on Focus Value of Iris Image)

  • 강병준;박강령
    • 대한전자공학회논문지SP
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    • 제43권2호
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    • pp.30-39
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    • 2006
  • 홍채 인식은 흥채 근육의 무의 패턴을 이용하여 동일인 여부를 판별하는 연구 분야이다. 이러한 홍채 인식에서 홍채 영상의 품질은 홍채 인식의 성능에 많은 영향을 준다. 이는 흥채 영상이 흐려지면, 홍채 패턴이 변형되어지므로, FRR(False Rejection Error)이 증가되기 때문이다. 홍채 영상을 흐려지게 만드는 주된 요인 가운데 하나가 카메라 렌즈의 초점(focus)이다. 기존의 흥채 인식 카메라는 고정 초점(fixed focusing) 방식과 가변 초점(auto-focusing) 방식이 있다. 고정 초점 방식은 초점 렌즈가 고정되어 있기 때문에 사용자가 직접 자신의 눈을 DOF(Depth of Field) 영역 안에 위치시켜야하고, DOF 영역이 매우 작은 한계가 있다. 가변 초점 방식은 사용자와 카메라 사이의 거리를 측정하여 초점이 잘 맞는 위치로 초점렌즈를 움직여서 선명한 영상을 취득한다. 하지만 부가적인 하드웨어 장비가 필요하기 때문에 카메라의 부피가 늘어나고 비용도 증가되므로 개인 인증을 위해 홍채인식을 하는 핸드폰과 같은 모바일 장비에서 사용되는데 어려움이 따른다. 따라서 본 논문은 이러한 기존의 홍채인식 카메라의 문제점들을 극복하기 위해 부가적인 하드웨어 장비 없이 고정 초점 방식 카메라에서 취득한 홍채 영상을 복원함으로써 소프트웨어적으로 DOF영역을 증가시키는 방법을 제안한다. 기존의 영상 복원 알고리즘은 반복적(iterative) 방법에 의해 최상의 복원 계수(parameter)를 검출하여 영상을 복원하였으나, 본 논문은 초점값을 이용하여 영상의 흐려짐의 정도를 판단하고, 흐려짐의 정도에 따라 미리 정의한 복원 계수를 선택함으로써 빠른 시간 안에 홍채 영상을 복원하는 방법을 제안한다. 실험 결과, Panasonic에서 만든 BM-ET100 카메라의 작동범위(Operation Range)를 48-53cm에서 46-56cm로 증가시킬 수 있었다.

쉼터거주자의 건강관리실태 및 대안 (Health Status and Health Care System of Homeless Shelter Residents)

  • 한영란;윤희상
    • 한국보건간호학회지
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    • 제28권3호
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    • pp.536-552
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    • 2014
  • Purpose: The purpose of this study was to explore how homeless shelter worker and public health nurses perceive health status and health care of homeless shelter residents (HSRs). Methods: Data collected through focus group interviews. In Focus group, in-depth discussions were between 150 to 160 minutes. Data analyzed using Krueger (1998) step analysis. Participants were seven experienced clinical social workers, nurses working homeless shelters, and public health center nurses for dosshouse people. Results: The results were 4 themes and 15 sub-themes: Characteristics of HSRs, perception of health and health problem of HSRs (alcohol related disease, hypertension Diabetics, gastro-intestinal disease, dental disease and infectios disease such as Tuberculosis, musculo-skeletal disease, prostate problem), health care status of HSRs(insufficient health care service, discrimination of medical staff, lack of health care management, low satisfaction community health care services), and the health care proposal of HSRs(nurse in homeless shelter, integrated health care system, understanding of homeless) Conclusion: Based on the findings of this study, health care programs focusing on understanding of HSRs and chronic diseases of HSRs increasing steadily although the management system is limited. Therefore, more systemized health care plan and health referral system for homeless people.

간호학생의 보건진료소 실습경험 (Nursing Students' Experience in Community Health Center Practice)

  • 박현주;장인순
    • 지역사회간호학회지
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    • 제21권2호
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    • pp.188-199
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    • 2010
  • Purpose: The objective of this study was to understand the meaning of experience on community health centers (post) practice of nursing students. Methods: This is qualitative research using focus groups. Data were collected through in-depth interviews performed from November 10 to December 11, 2009. The focus group interviews were conducted to 22 nursing students on their subjective experiences. The data were analyzed by the Colaizzi's method, in which the meaningful statements were extracted. Results: Seven theme-clusters were identified from fourteen themes and thirty-one sub-themes. The seven theme-clusters were 1) widening of experiences; 2) feeling of warm heart; 3) feeling of satisfaction; 4) feeling of being unfulfilled; 5) difficulties; 6) new awareness; and 7) good memories. Conclusion: Through a variety of relationships and self-regulation in community health centers (post) practice, the nursing students may have the feeling of worthiness, new awareness of community nursing, and visions for the future to rebuild.

외국계기업사례분석을 통한 유연근무제활성화방안 연구 (A Study on Activation Plans of Flexible Work Arrangements Based on a Qualitative Case Study of a Foreign-affiliated Firm)

  • 이현아;김선미;이승미
    • 가정과삶의질연구
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    • 제30권2호
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    • pp.173-187
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    • 2012
  • This qualitative case study focused on the activation plan of flexible work arrangements. We selected eight workers from a foreign affiliated firm that has various flexible work arrangements for in-depth interview and focus group interview. The workers were categorized into two groups; those who have experiences with flexible working and those who have needs for flexible working. We analyzed their condition of work-family life and experiences with flexible working. Through the focus group interview, we can find out the needs and suggestions about activation plans of flexible work arrangements.

저탄소 박판 강재의 Nd:YAG 레이저 용접부 형성에 미치는 공정변수의 영향 (Effect of Process Parameters on Bead Formation in Nd:YAG Laser Welding of Thin Steels)

  • 김기철;허재협
    • Journal of Welding and Joining
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    • 제19권3호
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    • pp.317-324
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    • 2001
  • This study deals with high power Nd:YAG laser welding of thin steels for small pressure vessels. Full penetration welding at the overlap joint was performed so as to assure sufficient weld strength. Results showed that mid-depth weld size reduced drastically with increasing the travel speed. Position of focus had little effect on the bead formation even though short focal system was used. However, the shape factor and the bead width had closely related with the position of focus. Based on the microstructural inspection, acceptable weld was obtained when the overlap clearance was controlled up to 20% of the base metal thickness. In the case that the joint contained more clearance than the critical value, both the tensile shear strength and the tear strength were reduced. Results also demonstrated that shielding gases were proved to play a key role as far as the bead formation characteristics was taken into consideration. Blowing dry air through 5mm in diameter nozzle produced narrower bead cross-section than that of argon or nitrogen shielding.

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Mothers' perceptions of children's food behaviors: use of focus group interview study

  • Lee, Young-Mee;Kim, Jung-Hyun;Oh, Yu-Jin;Lee, Min-June
    • Nutrition Research and Practice
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    • 제2권4호
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    • pp.259-268
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    • 2008
  • Children's food behaviors have been expressed in a various ways because of recent changes in their family environment. Thus, this study was performed to investigate in-depth qualitative research on the mother's perception on children's food behaviors by focused group interview. This study was designed in four steps of planning, collection of participants, process, and analysis. Participants for the focus group interview were recruited and sampled from households with elementary school students in the Seoul and Gyeonggido areas. Groups were divided by total income and education expense levels. 1) High income household: It is better to improve currently existing web sites for nutrition education. 2) Mid income household: Easy, practical, and inexpensive off-line cooking class/nutrition education classes for mothers are needed. Nutrition programs for children should be developed through mass media and be promoted in the broadcasting circle. 3) Low income household: Motivation is required for mothers' educatior and the serious nutritional problems of children should be informed through mass media and home correspondence from school. And interesting educational materials should be developed for children to read whenever they want.

근거이론에 기초한 플러스 사이즈 여성 소비자의 의류를 중심으로 한 외모관리에 관한 탐색적 연구 (Plus-size Women and Appearance Management with a Focus on Clothing -Grounded Theory Based Exploratory Study-)

  • 유혜경;고선영;김찬주
    • 한국의류학회지
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    • 제37권3호
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    • pp.306-319
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    • 2013
  • This study explores various issues of appearance management behavior for plus-size women in Korea with a focus on clothing. In-depth interviews and focused group interviews were conducted with 24 plus-size women. The interviews were recorded and the transcripts were analyzed based on grounded theory. Discomfort was the main phenomenon involving the experience of plus-size women related to appearance management. Psychological as well as physiological/physical discomfort, unmet needs (regarding clothing) and inconvenient shopping experiences were frequently mentioned. Causal conditions for discomfort were obesity, social stigma, and an underdeveloped clothing market for plus-size consumers. Interviewees developed strategies to cope with discomfort (suppressing clothing need, loss of interest in clothing, diversion from clothing needs, sole focus on physical comfort, dress-up and increase in shopping channels, and change in shopping patterns) that depended on contextual conditions (such as duration of obesity and attitudes of people) close to the interviewees. The discomfort of interviewees decreased or continued depending on if they became ambivalent about their obese condition, lost weight, or utilized plus-size specialty stores.

집속 이온빔을 이용한 투과 전자 현미경 시편의 표면 영향에 관한 연구 (Study on Surface Damage of Specimen for Transmission Electron Microscopy(TEM) Using Focused Ion Beam(FIB))

  • 김동식
    • 전자공학회논문지 IE
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    • 제47권2호
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    • pp.8-12
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    • 2010
  • TEM(Transmission Electrion microsopy) 투과전자현미경은 재료의 기초 구조 분석과 반도체 또는 생물시편의 미세 구조분석에 널리 사용되는 장비이다. TEM 분석은 필수적으로 목적에 부합되는 적절한 시편제작이 수반되어야 한다. 다양한 전자 현미경 시편 제작 방법 중 본 논문에서는 FIB(Focus Ion Beam)를 이용한 시편 제작법 중 시편에 입사되는 에너지와 이온 Gun과 시편과의 상호 각도, 이온 밀링 깊이 조절 등의 실험을 통하여 표면 손상 최소화를 벌크 웨이퍼와 패턴화된 시편에서 실험하였다. 최소화된 표면 영향성(약 5nm)을 패턴화된 시편에 구현하였다.

Consumer Values and Green Consumption: Implications for Marketing Strategy and Environmental Policy

  • Lee, Hyun Ju;Park, Seong-Yeon
    • Asia Marketing Journal
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    • 제19권4호
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    • pp.87-114
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    • 2018
  • The objective of this study is to find the effects of consumer values on eco-friendly buying behavior. This study examines environmental attitudes and involvement as moderating variables to explain eco-friendly buying behavior of consumers. Hypotheses were developed based on Focus Group Interviews, Depth Interviews, and literature reviews. To test such hypotheses, questionnaires were distributed and collected among female adults aged 18 or above, and who are either office workers or housewives. The analysis results show that personal values, sociocultural values, and values related to ecofriendly products affect consumers in their eco-friendly buying behavior. Among those values, concern about safety and health, eco-friendly culture and trend, willingness to pay price premiums and functional effects of eco-friendly products have significant effects on eco-friendly buying behavior. Reflecting these results, business marketers must appeal to consumers with more focus on safety and health, perceived consumer effectiveness, self-monitoring, eco-friendly culture and trend, media exposure, willingness to pay price premiums, design excellence and functional effects, to implement marketing communication strategies accordingly.

움직임 객체 기반의 하이브리드 깊이 맵 다운샘플링 기법 (Hybrid Down-Sampling Method of Depth Map Based on Moving Objects)

  • 김태우;김정훈;박명우;신지태
    • 한국통신학회논문지
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    • 제37A권11호
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    • pp.918-926
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    • 2012
  • 3차원 비디오 전송에 있어서, 렌더링에 사용되는 깊이 맵은 압축 효율을 위하여 일반적으로 낮은 해상도로 다운샘플링 되어 전송된다. 이때, 다운샘플링 과정에서 발생하는 오류는 디코딩 후의 적절한 업샘플링 기법을 통하여 효과적으로 복구할 수 있다. 하지만 기존의 연구들은 이러한 오류를 줄이기 위하여 여러 업샘플링 기법에 대해서만 초점이 맞춰져 있었다. 본 논문에서는 사람의 인지적인 화질을 보다 제고시키기 위하여 동적인 객체와 정적인 배경에 서로 다른 다운샘플링 비율을 적용시키는 새로운 하이브리드 깊이 맵 다운샘플링 기법을 제안한다. 실험적인 결과는 제안하는 방법이 시각적인 품질과 PSNR 측면에서의 이득이 있음을 보여준다. 또한 제안하는 방법은 여러 업샘플링 기법들과 호환이 가능하다.