• 제목/요약/키워드: systematic sampling

검색결과 306건 처리시간 0.022초

지리정보시스템을 활용한 서울시 유해대기오염물질 우선순위 측정지역 선정 (Selection of Priority Monitoring Areas for Hazardous Air Pollutants (HAPs) in Seoul using Geographic Information System)

  • 김성준;박현진;이상진;김창혁;이승복;최성득
    • 한국대기환경학회지
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    • 제34권2호
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    • pp.223-232
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    • 2018
  • As the Seoul metropolitan city has the largest numbers of population and vehicles, the citizens can be exposed to hazardous air pollutants(HAPs) mainly from the vehicular exhaust and human activities. In this study, we proposed a systematic method for the selection of priority monitoring areas for HAPs using Geographic Information System (GIS). First, emission parameters(emission data, vehicle registration, monitoring data, and so on) and population parameters (population and population density) were plotted using the inverse distance weighted (IDW) interpolation. Then, the interpolation data for individual parameters, which were normalized between 1 and 5 points, were compiled for 270 grids with a resolution of $2km{\times}2km$. The total score of each grid was calculated using weights(1~5) for the individual parameters. The final ranking of each grid was assigned by four scenarios with varying fractions of the emission and population parameters from 50 : 50 to 80 : 20. Consequently, nine grids were suggested as priority monitoring areas, and all of them are located in the southwestern part of Seoul.

예인수조용 스테레오스코픽 입자영상유속계 시스템의 불확실성 해석 (Uncertainty Assessment of a Towed Underwater Stereoscopic PIV System)

  • 서정화;설동명;한범우;유극상;임태구;박성택;이신형
    • 대한조선학회논문집
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    • 제51권4호
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    • pp.311-320
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    • 2014
  • Test uncertainty of a towed underwater Stereoscopic Particle Image Velocimetry (SPIV) system was assessed in a towing tank. To estimate the systematic error and random error of mean velocity and turbulence properties measurement, velocity field of uniform flow was measured. Total uncertainty of the axial component of mean velocity was 1.45% of the uniform flow speed and total uncertainty of turbulence properties was 3.03%. Besides, variation of particle displacement was applied to identify the change of error distribution. In results for variation of particle displacement, the error rapidly increases with particle movement under one pixel. In addition, a nominal wake of a model ship was measured and compared with existing experimental data by five-hole Pitot tubes, Pitot-static tube, and hot wire anemometer. For mean velocity, small local vortex was identified with high spatial resolution of SPIV, but has serious disagreement in local maxima of turbulence properties due to limited sampling rate.

경기지역 일부 초등학생의 안전의식과 안전사고 발생 실태 (Safety-awareness and Accident Occurrence of Elementary-school Students in Gyeonggi province)

  • 최혜정;소미현
    • 한국학교ㆍ지역보건교육학회지
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    • 제14권1호
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    • pp.61-70
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    • 2013
  • Objectives: The purpose of this study analyzes the characteristics of safety education in schools, experience of accidents, and safety awareness level of elementary school students. It also presents realistic guidelines for safety education, which can effectively lead to the safety behavior of students. Methods: We carried out questionnaire survey by convenient sampling method to 6th grade students of 3 elementary schools in Gyeonggi-do area that can understand the questionnaire and express their own opinion for safety awareness from February 15, 2013 to February 1, 2013. We used a self-administered questionnaire and analyzed 266 questionnaires except dishonestly answered 34 questionnaires. Results: 1. For accident occurrence by gender, male students was higher than female students. Male students was also higher than female students among students having an accident(${\chi}^2$=5.142, p=0.029). There was statistical significance in accident occurrence by how they go to school. Students going to school on foot have higher accident rate(${\chi}^2$=11.447, p=0.010). 2. In terms of safety awareness level, students having no accident was higher than students having an accident(F=3.828, p=0.005) and students usually keeping safety rules have higher safety awareness(F=14.285, p=0.000). 3. When parents give safety education to their children as often as possible, the safety awareness level of students was high(F=5.257, p=.006). 4. Students having an accident have no safety education experience than students having no accident(p<0.05). They have never had safety education from a health teacher. There was statistical significance(p<0.01). Conclusions: Accordingly, we need to make students have safety attitude to prevent safety accidents. To achieve it, safety awareness has to be inspired. Systematic and various education programs that can give connected education with local community network to the students and parents is required.

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Total Delay for Treatment among Cancer Patients: a Theory-guided Survey in China

  • Feng, Rui;Wang, De-Bin;Chai, Jing;Cheng, Jing;Li, Hui-Ping
    • Asian Pacific Journal of Cancer Prevention
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    • 제15권10호
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    • pp.4339-4347
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    • 2014
  • Purpose: This study aimed at exploring treatment delay (TD) among cancer patients in China with an attempt to develop a practical methodology facilitating frontline Chinese clinicians in promoting earlier cancer diagnosis and treatment. Materials and Methods: The study comprised framework development, qualitative interviews and paired factor rating. Framework development utilized systematic literature review, soft systems thinking and consensus groups. Qualitative interviews employed a checklist of open questions soliciting information about all the domains included the framework from cancer patients drawn via stratified randomized sampling of inpatients at 10 hospitals in Hefei, China. Paired factor rating used a self-developed computer aid and the interviewed patients as referring cases to weigh the relative importance of the factors listed in the framework in terms of their contributions to specific components of total delay (TD). Results: a) A conceptual framework was proposed consisting of a 6-step path to TD and 36 category determinants. b) A total of 227 patients were interviewed; their TD was 267.3 mean or 108 median days ranging from 0 to 2475 days; average appraisal, illness, behavioral, preparation and treatment delay accounted for 52.1%, 9.4%, 0.30%, 8.8% and 29.4% of the TD respectively. Individual side factors were rated substantially more important than environmental side factors (60% vs. 40%); most influential TD factors included cancer symptoms, overall health, family relations and knowledge about cancer and health. Conclusions: The framework proposed together with the interviewing and rating approaches used provide a potential new methodology for understanding cancer patients' TD and promoting earlier cancer treatment.

Allometric Modeling for Leaf Area and Leaf Biomass Estimation of Swietenia mahagoni in the North-eastern Region of Bangladesh

  • Das, Niamjit
    • Journal of Forest and Environmental Science
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    • 제30권4호
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    • pp.351-361
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    • 2014
  • Leaf area ($A_0$) and leaf biomass ($M_0$) estimation are significant prerequisites to studying tree physiological processes and modeling in the forest ecosystem. The objective of this study was to develop allometric models for estimating $A_0$ and $M_0$ of Swietenia mahagoni L. from different tree parameters such as DBH and tree height of mahogany plantations in the northeastern region of Bangladesh. A total of 850 healthy and well formed trees were selected randomly for sampling in the five study sites. Then, twenty two models were developed based on different statistical criteria that propose reliable and accurate models for estimating the $A_0$ and $M_0$ using non-destructive measurements. The results exposed that model iv and xv were selected on a single predictor of DBH and showed more statistically accuracy than other models. The selected models were also validated with an additional test data set on the basis of linear regression and t-test for mean difference between observed and predicted values. After that, a comparison between the best logarithmic and non-linear allometric model shows that the non-linear model produces systematic biases and underestimates $A_0$ and $M_0$ for larger trees. As a result, it showed that the bias-corrected logarithmic model iv and xv can be used to help quantify forest structure and functions, particularly valuable in future research for estimating $A_0$ and $M_0$ of S. mahagoni in this region.

서울 시내 궁궐 수원의 수질과 유동 특성 (Characteristics of Quality and Flow of Water Resources at Palaces in Seoul Metropolitan)

  • ;이재민;우남칠;김연태;이강진
    • 한국지하수토양환경학회지:지하수토양환경
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    • 제16권2호
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    • pp.61-76
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    • 2011
  • This study was objected to provide suggestions for best management practices to restore the cultural and historical values of the wells in Palaces as well as their water qualities. Water resources in the five Palaces in Seoul Metropolitan, including Gyeongbokgung, Changdeokgung, Changgyeonggung, Jongmyo Shrine, and Deoksugung, were surveyed for their physical flows and chemical compositions from April to July in 2010. Ground waters in most wells were found at depths within 5 m from the ground surface, showing typical water-table aquifer systems. Hydraulic gradients indicate water resources in Gyeongbokgung, Changdeokgung, and Changgyeonggung flowing toward south, and toward east in Deoksugung area. Especially, water-level fluctuation data at S-10 in Deoksugung implied the influence of groundwater discharge facility. In Jongmyo Shrine, water was not detected in wells, indicating the water level was lower than the well depth. Based on the water chemistry and stable isotope analyses, water resources and their qualities appeared to be formed by the water-rock interaction along the groundwater paths. S-10 (Deoksugung) and S-14 (Changgyeonggung) samples were contaminated with nitrate ($NO_3$) in levels of higher than Korean drinking water standard, 10 mg/L as $NO_3$-N, but once in four sampling campaigns. In the situation that water resources in Palaces still maintain natural characteristics, the materials that will be used for the restoration and improvement of the Palace water supplies should be carefully selected not to disturb the natural integrity. In addition, because the wells are located in the center of metropolitan area, a systematic monitoring should be applied to detect and to manage the potential impacts of underground construction and various pollution sources.

웰빙 트렌드 로하스(LOHAS)에 관한 외식 소비자의 인식 차이가 메뉴 선택 행동에 미치는 영향 (Influence of Different Perspectives about Well-being Trend LOHAS on the Menu Selecting Behavior of Diners-out)

  • 조우제
    • 한국조리학회지
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    • 제15권3호
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    • pp.307-323
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    • 2009
  • 조사대상자의 일반적인 특성과 외식 행동 특성은 빈도(N)와 백분율(%)로 나타내었으며, 조사대 상자의 일반적 특성에 따른 인식에 관한 차이를 알아보기 위해 $x^2$-검정을 실시하여 유의성을 검정하였고, 메뉴 선택행동은 요인분석(Factor analysis)을 실시하였으며, 메뉴 선택 요인과 일반적인 특성과의 차이(t-test & ANOVA)를 검정하였고, 건강지향도과 만족도와의 다중회귀분석(Multiple regression analysis)을 실시하였다. 인구통계적 변인들과 메뉴 선택 행동의 차이는 대체로 연령, 학력, 소득 수준이 높을수록 평균이 높게 나타나 웰빙 메뉴 선택 행동에 높은 관여를 보이는 것으로 조사되었으며, 메뉴 선택 행동이 건강지향성과 만족도에 미치는 영향에 관한 회귀분석결과 식생활 습관성은 건강지향성과 만족도에 영향을 미치지 못하는 것으로 조사되었다. 따라서 외식기업들은 이러한 집단을 마케팅 목표로 설정하여 그에 맞는 메뉴 개발 및 업체의 컨셉을 정하여 판매 촉진을 개선시키는 것이 바람직하다고 할 수 있다.

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노인의 지속적 자원봉사활동 경험 : 현상학적 연구 (Continuous Volunteering Experience in Elderly People : A Phenomenological Research)

  • 유정숙;김가득
    • 한국사회복지학
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    • 제62권3호
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    • pp.247-270
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    • 2010
  • 본 연구는 노인의 지속적 자원봉사활동 경험이 그들의 삶에 부여하는 의미와 본질은 어떤 것인가를 이해하기 위해 Giorgi의 현상학적 연구방법을 사용하여 자료를 분석하였다. 짧게는 6년, 길게는 23년 이상 지속적으로 봉사활동에 참여하고 있는 전라북도 거주 노인 5명을 대상으로 심층면접을 실시하였다. 분석 결과, '마음에서 우러나옴', '노후에 새로운 삶을 발견함', '아낌없이 주는 즐거움', '삶의 중심으로 들어온 봉사활동', '쉼 없는 봉사활동'이라는 5개의 구성요소를 도출하고, 본질적 주제는 '다시 찾은 활기 찬 삶의 기쁨'으로 나타났다. 본 연구에서 밝혀진 노인의 지속적 자원봉사활동 경험의 본질은 '성공적 노후생활의 구성요소'와 대체로 일치한다. 따라서 자원봉사활동이 '개인적 차원의 선행'이라는 의미에서 '성공적 노후생활'의 실현을 위한 사회적 차원의 조건이라는 의미로 해석되어야 하는 인식론적 전환이 이루어져야 할 것이고, 이를 구현하기 위해 국가 및 공공차원의 지원 대책이 적극 마련되어야 할 것이다.

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직무순환을 경험한 간호사의 경력만족 예측모형 (A Model for Predicting Career Satisfaction of Nurses Experiencing Rotation)

  • 신숙;유미
    • 대한간호학회지
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    • 제47권4호
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    • pp.551-561
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    • 2017
  • Purpose: This study aimed to present and test a structural model for describing and predicting the factors affecting subjective career satisfaction of nurses experiencing rotation and to develop human resources management strategies for promoting their career satisfaction related to rotation. Methods: In this cross-sectional study, we recruited 233 nurses by convenience sampling who had over 1 year of career experience and who had experienced rotation at least once at G university hospital. Data were collected from August to September in 2016 using self-reported questionnaires. The exogenous variables consisted of rotation perception and rotation stress. Endogenous variables consisted of career growth opportunity, work engagement, and subjective career satisfaction. A hypothetical model was tested by asymptotically distribution-free estimates, and model goodness of fit was examined using absolute fit, incremental fit measures. Results: The final model was approved and had suitable fit. We found that subjective career satisfaction was directly affected by rotation stress (${\beta}=.20$, p=.019) and work engagement (${\beta}=.58$, p<.001), indirectly affected by rotation perception (${\beta}=.43$, p<.001) through career growth opportunity and work engagement. However, there was no total effect of rotation stress on subjective career satisfaction (${\beta}=-.09$, p=.270). Career growth opportunity directly and indirectly affected subjective career satisfaction (${\beta}=.29$, p<.001; ${\beta}=.28$, p<.001). These variables accounted for 65% of subjective career satisfaction. Conclusion: The results of this study suggest that it is necessary to establish systematic and planned criteria for rotation so that nurses can grow and develop through sustained work and become satisfied with their career.

Evaluation of DMS Flux and Its Conversion to SO(sub)2 in Tropical ACE 1 Marine Boundary Layer

  • Shon, Zang-Ho;Taekyung Yoon;Kim, Jungkwon
    • Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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    • 제4권3호
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    • pp.139-148
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    • 2000
  • A mass balance/photochemical modeling approach was used to evaluate the sea-to-air dimethyl sulfide (DMS) fluxes in tropical regions and part of the Southern Ocean. The flux determinations were based on 10 airborne observations by ACE 1 transit flights (i.e., Flights 4-9 and 29-32). The DMS flux values for the tropical regions ranged from 1.0 to 7.4 $\mu$mole/$m^2$/day with an average estimate of 4.2$\pm$2.3 $\mu$mole/$m^2$/day. The seasonal variations in the DMS flux predicted for the equatorial Pacific Ocean based on atmospheric DMS measurements were not entirely consistent with those derived from seawater DMS measurements were not entirely consistent with those derived from seawater DMS measurements reported in previous literature. Inhomogeneities in the DMS flux field were found to cause significant shifts in the atmospheric DMS levels even in the same sampling location. Accordingly, no definitive statement can be made at this stage regarding systematic differences or agreements in the DMS flux estimates from the two approaches. Moreover, this study strongly suggests that DMS oxidation is the most likely dominant source of SO$_2$in tropical regions, which is also supported by another set of compiled observations. Finally, these SO$_2$observations indicate that, when significant data was available for both the boundary and buffer layers, the vertical SO$_2$gradient between these two zones was primarily negative.

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