• 제목/요약/키워드: qualitative and quantitative evaluation

검색결과 732건 처리시간 0.032초

Fuzzy 이론을 활용한 건설프로젝트 리스크 분석 및 평가 시스템 (FREES : Fuzzy Risk Evaluation Expert System)

  • 조익래;반찬식
    • 한국건설관리학회논문집
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    • 제1권1호
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    • pp.53-62
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    • 2000
  • 본 연구는 건설 프로젝트의 초기 단계에서 미래에 발생할 수 있는 리스크를 리스크분할체계를 통하여 파악하고, 파악된 리스크를 효과적이고 체계적으로 분석 및 평가하여 프로젝트 초기단계에서 리스크를 분석하고 평가할 수 있는 절차와 계산틀을 제시하였다. 그에 따라, 프로젝트 기획 및 입찰 전 단계에서 건설공사 이행과정에서 발생할 가능성이 있는 리스크를 분석 및 평가하기 위해 FREES(Fuzzy Risk Evaluation Expert System)을 제안하였으며 가상 시나리오를 설정하여 모델에 대한 검증을 수행하였다. FREES는 기존의 IF-THEN 지식베이스를 사용한 전문가 시스템과 비교했을 경우 퍼지소속함수를 사용함으로써 규칙의 수를 현저하게 줄일 수 있으며 지식베이스의 구축과 변경 및 삭제 등이 용이하기 때문에 시간의 변화에 따라 다양하게 변화하는 리스크의 크기나 영향정도를 쉽게 반영할 수 있다.

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Image Quality and Lesion Detectability of Lower-Dose Abdominopelvic CT Obtained Using Deep Learning Image Reconstruction

  • June Park;Jaeseung Shin;In Kyung Min;Heejin Bae;Yeo-Eun Kim;Yong Eun Chung
    • Korean Journal of Radiology
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    • 제23권4호
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    • pp.402-412
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    • 2022
  • Objective: To evaluate the image quality and lesion detectability of lower-dose CT (LDCT) of the abdomen and pelvis obtained using a deep learning image reconstruction (DLIR) algorithm compared with those of standard-dose CT (SDCT) images. Materials and Methods: This retrospective study included 123 patients (mean age ± standard deviation, 63 ± 11 years; male:female, 70:53) who underwent contrast-enhanced abdominopelvic LDCT between May and August 2020 and had prior SDCT obtained using the same CT scanner within a year. LDCT images were reconstructed with hybrid iterative reconstruction (h-IR) and DLIR at medium and high strengths (DLIR-M and DLIR-H), while SDCT images were reconstructed with h-IR. For quantitative image quality analysis, image noise, signal-to-noise ratio, and contrast-to-noise ratio were measured in the liver, muscle, and aorta. Among the three different LDCT reconstruction algorithms, the one showing the smallest difference in quantitative parameters from those of SDCT images was selected for qualitative image quality analysis and lesion detectability evaluation. For qualitative analysis, overall image quality, image noise, image sharpness, image texture, and lesion conspicuity were graded using a 5-point scale by two radiologists. Observer performance in focal liver lesion detection was evaluated by comparing the jackknife free-response receiver operating characteristic figures-of-merit (FOM). Results: LDCT (35.1% dose reduction compared with SDCT) images obtained using DLIR-M showed similar quantitative measures to those of SDCT with h-IR images. All qualitative parameters of LDCT with DLIR-M images but image texture were similar to or significantly better than those of SDCT with h-IR images. The lesion detectability on LDCT with DLIR-M images was not significantly different from that of SDCT with h-IR images (reader-averaged FOM, 0.887 vs. 0.874, respectively; p = 0.581). Conclusion: Overall image quality and detectability of focal liver lesions is preserved in contrast-enhanced abdominopelvic LDCT obtained with DLIR-M relative to those in SDCT with h-IR.

건강증진을 위한 도시공원의 물리적 환경요소 평가 - 서울시를 대상으로 - (The Evaluation of Physical Environmental Factors in Urban Parks for Healthy City - Focus on Seoul -)

  • 채진해;김원주
    • 한국조경학회지
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    • 제48권4호
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    • pp.29-40
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    • 2020
  • 본 연구는 건강증진을 위한 도시공원 평가하기 위해 물리적 환경 요소를 해외사례와 선행연구를 통해 지표를 선정하고, 이를 정량적·정성적으로 분석하였다. 조사대상지는 서울시에 조성된 근린공원을 지역적 분배를 고려하여 서대문독립공원, 홍릉근린공원, 고척근린공원, 신림근린공원, 청담근린공원, 개포근린공원, 숭인근린공원 7개이다. 평가 지표는 정량적 지표 (공원의 배후지역 환경, 공원 특성, 공원 시설물 3가지 분류에 따른 12가지 요소), 정성적 지표(접근성, 안전성, 편의성, 활동성, 어메니티 5가지 분류에 따른 14가지 요소)를 선정하였다. 지표 선정방법은 전문가 자문회의를 통해 선정하였으며, 물리적 환경 인식 요소의 평가방법은 전문가와 조사원이 현장관찰을 통해 3점 척도(상·중·하)로 조사하였다. 분석결과, 첫째, 건강증진을 위한 지표는 운동시설이나 산책로 뿐 아니라, 휴식공간, 여가 및 문화시설, 접근성, 청결, 식수대 등 건강 활동을 지원하는 다양한 요소들이 주요한 지표임을 알았다. 둘째, 정량적인 지표로는 요건을 갖추고 있다 할지라도 정성적인 평가에서는 실제 구현시키거나, 이용하는데 불편함이 많아 공원의 물리적 환경에 대한 정량적 정성적 평가가 동시에 이루어져야 한다. 셋째, 물리적 환경요소에 대한 정성적 평가 결과 유형별, 공원별 점수차가 나타났는데, 건강증진을 위한 운동시설, 체력단련시설 등 활동성보다는 접근성, 안전성, 편의성과 같은 간접적 지표가 부족한 것으로 나타났다. 최근 COVID-19 등으로 공원 이용률이 증가하고 있고, 포스트 코로나 시대에는 공원의 서비스 증진을 위해 더욱 노력해야 한다. 이를 위해 정기적으로 정량적·정성적 지표를 평가하여 공원의 서비스를 증진시키고, 직접적 요인 뿐 아니라 간접적·보안적인 지표들에 대한 서비스 고려가 필요하다.

타이어 검사를 위한 Shearogrpahy의 응용 (Shearography in Tire Industry)

  • 김경석;강기수;윤철성;양승필
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2003년도 춘계학술대회
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    • pp.298-303
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    • 2003
  • In recent years, shearogrpahy has significantly improved capabilities in the areas of unbond and separation detection in tires. Although shearography has many advantages for qualitative evaluation, the technique remains the problem of quantitative analysis of inside defects, because shearography needs several effective factors including the amount of shearing, shearing direction and induced load, which exist as barrier for the quantitative analysis of inside defects. Since the factors are highly dependent on inspectors skill and also affect the in-situ workability. The factors were optimized and the size of cracks inside of pipeline and tire has been quantitatively determined.

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토양도 자료를 활용한 연초 경작지의 비옥도 평가 (Soil Fertility Evaluation with Adoption of Soil Map Database for Tobacco Fields)

  • 홍순달;박효택
    • 한국토양비료학회지
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    • 제32권2호
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    • pp.95-108
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    • 1999
  • 충북 진천, 음성, 괴산, 중원군과 충남 천원군, 그리고 경북 청도, 성주, 안동군에 분포하는 101개 연초 경작지에 대하여 토양의 화학성 및 토양도 자료들을 이용한 토양 비옥도를 평가하기 위하여 1985년부터 2년 동안포장시험이 수행되었으며 또한 동일 토양에 대한 포트시험도 병행하여 서로 비교하였다. 무비구의 연초 수량을 토양 비옥도 요인으로 고려하여 9개 화학성과 10개 토양도 자료들을 포함하는 19개 독려변수들로 평가하였다. 19개 독립변수들은 11개의 정량적 지표들과 9개의 정성적 지표들로 구분하여 BAS의 REO와 CLM model로 다중선형 회귀분석을 수행하였다. 무비구 연초 수량은 최저치와 최고치 간에 포트시험의 경우 5.0-5.5배, 포장시험의 경우 8.2-14.9배의 차이를 보여 공시토양의 다양한 비옥도 특성을 나타냈다. 무비구 수량과 밀접한 상관을 보인 화학적 지표는 포장시험과 포트시험간뿐 아니라 년차 간에도 상이하였으며, 또한 포장시험의 무비구 수량에 기여하는 정량적 지표들의 표준화 편회귀계수는 모두 1.0 미만을 보여 비옥도 평가를 위한 탄일 유효도지표의 선발이 어렵다는 것을 시사하였다. 비옥도에 대한 독립변수들의 다중선형회귀 평가는 단일 지표에 의한 평가보다 매우 양호하였으며 화학적 지표들 이외에 토양도의 정량적 및 정성적 지표들을 평가에 포함시킴에 따라 결정계수($R^2$)는 점진적으로 증가되었다. 즉 예를 들면 1985년도 무비구 수량에 대한 다중선형회귀의 결정계수는 단일지표 $NO_3-N$ 함량에 의한 평가 0.244에 비하여 화학적 지표들에 의한 평가는 0.422, 토양도의 정량적 지표들의 추가되면 0.503, 그리고 정성적 지표들을 추가하면 0.633으로 증가되었다. 따라서 토양 화학성 이외에 토양도 자료들을 포함하는 정량적 및 정성적 지표들에 의한 다중선형회귀 분석방법은 연초 경작지의 비옥도 평가를 위한 유의성 있는 모델로 추정되었다.

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자연환경에 대한 주민의 평가와 평가 요인에 관한 연구 (A Study of Resident's Evaluation on Natural Environment and the Evaluation Factors)

  • 이동근
    • 환경영향평가
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    • 제6권1호
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    • pp.67-76
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    • 1997
  • The purpose of this research is to draw out the factors affecting the residents' evaluation on valuable animal and vegetation and the naturality of vegetation seen near regional environment. With this purpose, Questionnaire research and vegetation survey focusing on area of types of vegetation and species of big trees were made in 30 points of midstream of Tama River, Tokyo, Japan. The questionnaire research was based on basin environment units in order to be reflective of regional natural environment. The vegetation was classified into 5 types according to its flora and observed the covering area of each points and types through the aerial photograph. In addition, the species of big trees in habitat were listed by the survey. Results as below came out by analyzing the outcome of the questionnaire research and vegetation survey by multiple regression. First, residents are most likely not to distinguish precisely between the quantitative and qualitative aspects of vegetation. Both of the researches are apt to be influenced by quantitative factors of vegetation. Second, residents are assumed to consider forest of big trees, inhabitant of groups of big trees, highly natural.

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Nondestructive Evaluation Technology and Reliability of Products

  • Lee, Joon-Hyun;Lee, Seung-Suck
    • 한국신뢰성학회:학술대회논문집
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    • 한국신뢰성학회 2001년도 정기학술대회
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    • pp.235-238
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    • 2001
  • It is well known that the reliability of materials of mechanical products is becoming more and more important not only for assurance of quality, but for international competition of products. In order to assure the reliability of materials or mechanical products nondestructive evaluation (NDE) techniques are playing more important roles. The existence of Internal defects in materials or mechanical parts is served as crack initiation site during the various loading condition. Historically, nondestructive evaluation (NDE) technique has been used almost exclusively for detecting microscopic discontinuities In materials or mechanical parts after they have been in service to expand the role of the NDE to include all aspects of materials production and application. Research efforts are being directed at developing and perfecting NDE techniques capable of monitoring (1) materials production processes (2) material integrity following transport, storage and fabrication and (3) the amount and rate of degradation during service. In addition, efforts are underway to develop technique capable of quantitative discontinuity sizing, permitting determination of response using fracture mechanics analysis, as well as techniques for quantitative materials characterization to replace the qualitative techniques used in the past. In this paper, the important role of NDE technology for reliability assurance of materials/mechanical parts is introduced.

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독일에서의 환경영향의 정량적 평가 (Quantification of Ecological Impact as a Basis for Evaluation)

  • Schweppe-Kraft, Burkhard
    • 환경영향평가
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    • 제2권2호
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    • pp.59-71
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    • 1993
  • Evaluation methods are employed in environmental impact assessment to choose between different project site, to determine the required measures to compensate impact and to decide whether the environmental impacts are more important than the social or economic effects of a project. The main obstacles that restrict use of quantitative evaluation method are a Lack of knowledge about the environmental effects (e.g. if impacts on wildlife or landscape amenities are predicted) and the relative importance of economic and social issues compared with nature conservation stability of ecosystem or landscape beauty. In Germany, the most common method for site planning is the "ecological risk analysis". It is a kind of multi-criteria-decision-method based on quantitative and qualitative description and ordinal ranking. The various kinds of "ecological balancing methods" that are more recently developed (within the last decade) to quantify the required amount for compensatory measures instead often use cardinal figures to express the value of ecosystems, the intensity of impacts, the need for additional measures to compensate for long recuperative periods when restoring ecosystems and so on. There are still only a view attempts to quantify decisions between environmental and socio-economic issues. Multicriteria-analysis as well as cost-benifit-analysis was used. Some new approaches which are still in a preliminary status are based on contingent valuation and on calculations for compensatory payments (instead of compensatory measures).

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AHP 및 Fuzzy를 이용한 제품기획단계에서의 안전성 평가 (A Safety Evaluation Method for a Product Design Planning Stage: Application of AHP and Fuzzy)

  • 박지영;조암
    • 대한인간공학회지
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    • 제27권2호
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    • pp.15-24
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    • 2008
  • As users increasingly recognize the importance of safety and the Product Liability comes into effect, a company should take responsibility of protecting the users who use its product. In order to produce a safe product and satisfy the needs of users, it is critical for develope opriately and understand the characteristics of the product accurately. Furthermore, a safe product can be realized by considering a safety level of the product in a whole product development process. However, in general, product development projects hardly evaluate the safety of a product in the product planning step. In addition, most of safety evaluation methods which are applied in the product planning step have a tendency to be qualitative because a detailed product design step. Therefore, this research aims at enhancing the performance of the safety evaluation process by applying quantitative methods such as 'AHP' and 'Fuzzy'. AHP can help analysts derive the weight of safety factors. Fuzzy is applied to evaluate the degree of safety of product elements in this paper. The proposed method will be able to improve the safety level of a product by using the quantitative methods in the product planning step.

전자상거래 서비스 품질 인증에 관한 연구 (Certifying the Quality of Electronic Commerce Services)

  • 최덕원
    • 품질경영학회지
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    • 제33권2호
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    • pp.1-12
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    • 2005
  • An extensive literature review has been made in this paper to build the evaluation hierarchy structure for the certification of electronic commerce services. In building the evaluation hierarchy structure, major candidate evaluation factors are selected by bench marking the various certification practices, including the Malcolm Baldrige award, ISO9000, and BSC(balanced scorecard) techniques. This paper deployed principal component analysis and factor analysis techniques to develop a statistically solid and systematic evaluation model. The final evaluation model, as presented in this paper as a model for the certification of electronic commerce services, produces a numeric score on the 100% scale, which can be served as a metric for the certification decision. The AHP technique was used in converting the various qualitative and quantitative evaluation values into a single measure for the certification decision.