• 제목/요약/키워드: structural indicators

검색결과 254건 처리시간 0.027초

CT 영상에서 골다공증 판별 방법의 성능 향상 (A Performance Enhancement of Osteoporosis Classification in CT images)

  • 정성태
    • 한국멀티미디어학회논문지
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    • 제19권8호
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    • pp.1248-1259
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    • 2016
  • Classification methods based on dual energy X-ray absorptiometry, ultrasonic waves, and quantitative computed tomography have been proposed. Also, a classification method based on machine learning with bone mineral density and structural indicators extracted from the CT images has been proposed. We propose a method which enhances the performance of existing classification method based on bone mineral density and structural indicators by extending structural indicators and using principal component analysis. Experimental result shows that the proposed method in this paper improves the correctness of osteoporosis classification 2.8% with extended structural indicators only and 4.8% with both extended structural indicators and principal component analysis. In addition, this paper proposes a method of automatic phantom analysis needed to convert the CT values to BMD values. While existing method requires manual operation to mark the bone region within the phantom, the proposed method detects the bone region automatically by detecting circles in the CT image. The proposed method and the existing method gave the same conversion formula for converting CT value to bone mineral density.

환경시설물 대상 홍수취약성 평가지표 개발에 관한 연구 - 하수처리장을 중심으로 - (A Study on Development of Flood Vulnerability Evaluation Indicators for Sewage Treatment Plant)

  • 노재덕;한지희;이창희
    • 융합정보논문지
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    • 제10권12호
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    • pp.110-118
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    • 2020
  • 본 연구에서는 환경시설을 대상으로 침수피해에 대비한 재해 예방능력을 강화하고자 정량적인 부분뿐만 아니라 정성적인 부분을 고려한 홍수취약성 평가지표를 개발하고자 하였다. 이를 위해 환경시설의 침수에 취약한 시설물을 분석하고 구조적, 비구조적인 평가지표로 구분하여 개발하였다. 구조적 평가지표는 환경시설에 취약한 측면을 시설의 유형적인 측면에 대해 11개의 평가지표를 제시하였으며, 비구조적 평가지표는 내부인자와 외부인자로 구분하여 시설의 운영·상태 등 무형적인 측면에 대해 내부인자 8개와 외부인자 6개로 제시하였다. 본 연구에서 제시한 홍수취약성 평가지표는 기존 환경시설물의 침수피해 대비 홍수취약성에 대해 평가할 수 있도록 함으로써 홍수에 대한 대비할 수 있을 것으로 기대된다.

Online automatic structural health assessment of the Shanghai Tower

  • Zhang, Qilin;Tang, Xiaoxiang;Wu, Jie;Yang, Bin
    • Smart Structures and Systems
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    • 제24권3호
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    • pp.319-332
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    • 2019
  • Structural health monitoring (SHM) is of great importance to super high-rise buildings. The Shanghai Tower is currently the tallest building in China, and a complete SHM system was simultaneously constructed at the beginning of the construction of the tower. Due to the variety of sensor types and the large number of measurement points in the SHM system, an online automatic structural health assessment method with few computations and no manual intervention is needed. This paper introduces a structural health assessment method for the Shanghai Tower that uses the coefficients of an autoregressive (AR) time series model as structural state indicators. An analysis of collected data indicates that the coefficients of the AR model are affected by environmental factors, and the principal component analysis method is used to remove the influence of environmental factors. Finally, the control chart method is used to track the changes in structural state indicators, and a plan for online automatic structure health state evaluation is proposed. This method is applied to long-term acceleration and inclination data from the Shanghai Tower and successfully identifies the changes in the structural state. Overall, the structural state indicators of the Shanghai Tower are stable, and the structure is in a healthy state.

Wavelet analysis and enhanced damage indicators

  • Lakshmanan, N.;Raghuprasad, B.K.;Muthumani, K.;Gopalakrishnan, N.;Basu, D.
    • Smart Structures and Systems
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    • 제3권1호
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    • pp.23-49
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    • 2007
  • Wavelet transforms are the emerging signal-processing tools for damage identification and time-frequency localization. A small perturbation in a static or dynamic displacement profile could be captured using multi-resolution technique of wavelet analysis. The paper presents the wavelet analysis of damaged linear structural elements using DB4 or BIOR6.8 family of wavelets. Starting with a localized reduction of EI at the mid-span of a simply supported beam, damage modeling is done for a typical steel and reinforced concrete beam element. Rotation and curvature mode shapes are found to be the improved indicators of damage and when these are coupled with wavelet analysis, a clear picture of damage singularity emerges. In the steel beam, the damage is modeled as a rotational spring and for an RC section, moment curvature relationship is used to compute the effective EI. Wavelet analysis is performed for these damage models for displacement, rotation and curvature mode shapes as well as static deformation profiles. It is shown that all the damage indicators like displacement, slope and curvature are magnified under higher modes. A localization scheme with arbitrary location of curvature nodes within a pseudo span is developed for steady state dynamic loads, such that curvature response and damages are maximized and the scheme is numerically tested and proved.

임상전문분야별 의사 설문조사를 통한 병원서비스 평가 방법 연구 (A study on a hospital services evaluation method by physician survey)

  • 장원기;문옥륜
    • Journal of Preventive Medicine and Public Health
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    • 제29권4호
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    • pp.815-829
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    • 1996
  • A physician survey was done by mailing for the purpose of performing hospital services evaluation and ranking. A slightly over one thousand samples were drawn from the list of professional societies, and 324 physicians(about 32 percent) replied. This study has focused on developing easy and simple method to evaluate hospital services, and providing patients with useful information. Hospital service structure and process were evaluated without outcome evaluation, because it is difficult to obtain reliable data regarding health services outcome indicators. Clinical specialty was targeted to evaluate, and three specialties were chosen, that is obstetrics & gynecology, cardiology, and proctology. Among 16 structural indicators, four indicators were finally chosen in each specialty by respondent specialists. And then using these indicators, structural score was calculated for study hospitals. For process evaluation, physicians were requested to nominate five most famous hospitals. The nomination score and structural score were summed up to produce final score and hospital ranking. This method is very easy to conduct rather than other hospital services evaluation methods prevailing in Korea. And it is more useful for patients to choose hospitals, according to his/her own purpose, because it gives high ranking hospitals with specific clinical specialty.

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식·의약 위해 감시체계(K-RISS)의 우선순위 평가를 위한 시계열 구조변화 기반 기준선 설정 모델 개발 (Development of a Baseline Setting Model Based on Time Series Structural Changes for Priority Assessment in the Korea Risk Information Surveillance System (K-RISS))

  • 진현정;허성윤;이헌주;장보윤
    • 한국환경보건학회지
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    • 제50권2호
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    • pp.125-137
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    • 2024
  • Background: The Korea Risk Information Surveillance System (K-RISS) was developed to enable the early detection of food and drug safety-related issues. Its goal is to deliver real-time risk indicators generated from ongoing food and drug risk monitoring. However, the existing K-RISS system suffers under several limitations. Objectives: This study aims to augment K-RISS with more detailed indicators and establish a severity standard that takes into account structural changes in the daily time series of K-RISS values. Methods: First, a Delphi survey was conducted to derive the required weights. Second, a control chart, commonly used in statistical process controls, was utilized to detect outliers and establish caution, attention, and serious levels for K-RISS values. Furthermore, Bai and Perron's method was employed to determine structural changes in K-RISS time series. Results: The study incorporated 'closeness to life' and 'sustainability' indicators into K-RISS. It obtained the necessary weights through a survey of experts for integrating variables, combining indicators by data source, and aggregating sub K-RISS values. We defined caution, attention, and serious levels for both average and maximum values of daily K-RISS. Furthermore, when structural changes were detected, leading to significant variations in daily K-RISS values according to different periods, the study systematically verified these changes and derived respective severity levels for each period. Conclusions: This study enhances the existing K-RISS system and introduces more advanced indicators. K-RISS is now more comprehensively equipped to serve as a risk warning index. The study has paved the way for an objective determination of whether the food safety risk index surpasses predefined thresholds through the application of severity levels.

병원 재무비율 지표들 간의 구조적인 관계 분석 (An Analysis of Structural Relationships among Financial Indicators of Hospitals in Korea: Applying Structural Equation Modeling(SEM))

  • 정민수;이건형;최만규
    • 보건행정학회지
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    • 제18권2호
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    • pp.19-38
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    • 2008
  • Financial ratios are key indicators of an organization's financial and business conditions. Among various financial indicators, profitability, financial structure, financial activity and liquidity ratios are frequently used and analyzed. Using the structural equation modeling(SEM) technique, this study examines the structural causal relationships among key financial indicators. Data for this study are taken from complete financial statements from 142 hospitals that passed the standardization audit undertaken by the Korean Hospital Association from 1998 to 2001 for the purpose of accrediting teaching hospitals. In order to improve comparability, ratio values are standardized using the Blom's normal distribution. The final model of the SEM has four latent constructs: financial activity(total asset turnover, fixed asset turnover), liquidity(current ratio, quick ratio, collection period), financial structure(total debt to equity, long-term debt to equity, fixed assets to fund balance), and profitability(return on assets, normal profit to total assets, operating margin to gross revenue, normal profit to gross revenue). While examining several model fit indices(Chi-square (df) = 178.661 (40), likelihood ratio=4.467, RMR=.11, GFI=.849, RMSEA=.157), the final SEM we employed shows a relatively good fit. After examining the path coefficient of the constructs, the financial structure of the hospital affects the hospital's profitability in a statistically significant way. A hospital which utilizes its liabilities, more specifically fixed liabilities, and makes a stable investment decision for fixed assets was found to have a higher profitability than other hospitals. Then, the standard path coefficients were examined to directly compare the influence of variables. It was found that there were no statistically significant path coefficients among constructs. When it comes to variables, however, statistically significant relationships were found. between. financial activity and. fixed. asset turnover, and between profitability and normal profit to gross revenue. These results show that the observed variables of fixed asset turnover and normal profit to gross revenue can be used as indicators representing financial activity and profitability.

LISREL 구조방정식 모델에 의한 농촌 관광농원의 환경친화성 평가 모형 추정 (Evaluation Model for Environmentally Friendliness of Tourism Farms by LISREL Structural Equation Model)

  • 엄붕훈
    • 농촌계획
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    • 제5권2호
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    • pp.56-65
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    • 1999
  • Recently, new concept and paradigm of 'Environmentally-Friendliness' is taking a growing interest in environmental planning and design. This study is to establish the evaluation model for environmentally-friendliness of 'Tourism Farms' in rural areas by LISREL structural equation model. A questionnaire survey was conducted for deputy manager group and expert group. As the Result of LISREL structural equation model, the environmentally-friendliness of tourism farms is composed of three categories. First, conservation of global environment (Low Impact), second, friendliness to surrounding nature(High Contact), and third, environmental health and amenities (Health & Amenity). Five indicators, such as (1)saving of energy and water resource, (2)reduction and reuse of garbage, (3)natural purification of sewage disposal, (4)utilization of natural energy, (5)campaign and education programs of environmentally-friendliness, were affecting the first category, i.e., conservation of global environment(Low Impact). Friendliness to surrounding nature (High Contact) is affected by 3 indicators, (1)contact to nature and diverse green areas, (2)water intimate & contact areas, (3)natural ecology observation by biotope. Finally, the dimension of environmental health and amenity is affected by 3 indicators, (1)nature affinity by farming experience, (2)environmental-friendliness of soil & crops by organic farming, (3) campaign and education programs of environmentally-friendliness. Total coefficient of determination of the structural equation model by LISREL was 0.897, which showed high explanatory power.

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임상간호 질 평가를 위한 구조, 과정, 결과 기준지표의 비교 분석 연구 (Comparative Analysis of Structural, Process, and Outcome Indicators for Evaluating the Quality of Nursing Care)

  • 김영숙;김혜순;김정엽
    • 대한간호학회지
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    • 제28권1호
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    • pp.17-25
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    • 1998
  • This study was done to evaluate the quality of clinical nursing care using the variables of structure, process, and outcome and to analyze the relationship between the variables. This study also explored which variables are validating indicators to evaluate the quality of nursing care. The results analyzed by multiple regression showed that, generally structural variables did not contribute to the variance in outcome scores, but process variables of nursing care contributed significantly to the outcome variable of patient satisfaction. A combination of structure and process variables explained outcome variables more than structural variables alone. Also, patient satisfaction and hospital preference were significantly related to each other. Therefore, if nursing quality evaluation relies solely upon on structural variables such as number of available nurses and workload, it would be inaccurate because process variables of nursing care are strongly related to outcome variables and the two categories of structure and process variables helped to strengthen the relationships. Thus, it is important to focus on variables of structure, process, ant outcome together in evaluating nursing care quality.

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지적자본 관점에서의 과학기술계 연구기관 평가지표 분석 (Analysing Evaluation Indicators for the Research Institutes in Science & Technology Sector in the Perspective of Intellectual Capital Model)

  • 이찬구
    • 기술혁신연구
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    • 제15권2호
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    • pp.177-209
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    • 2007
  • This work firstly aims to analyse the balance between tangibles and intangibles as well as among human capital, structural capital and relational capital of evaluation indicators for the research institutes in science and technology sector conducted in 2006, by adopting intellectual capital model. The research question of this work comes from that while the R&D activity can produce both tangibles and intangibles, there have no been methodologies to relevantly measure and rationally judge these, in particular, intangible performance. The result shows that the institute evaluation system in 2006 had given more weight on tangibles and structural capital than intangibles and other intellectual capitals such as human capital and relational capital, in comparison to the past evaluation system, even though, in principle, the current evaluation system has to deal with the intangible research performances as well as tangible ones in economic, social and cultural perspective. Finally, based on these analysis, I will try to suggest some policy directions for overcoming the deficits of indicators in institute evaluation system.

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