• 제목/요약/키워드: level set function

검색결과 464건 처리시간 0.03초

활성 윤곽선 모델을 이용한 얼굴 경계선 추출 (Facial Boundary Detection using an Active Contour Model)

  • 장재식;김은이;김항준
    • 전자공학회논문지CI
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    • 제42권1호
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    • pp.79-87
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    • 2005
  • 본 논문에서는 복잡한 환경에서 정확한 얼굴영역의 경계를 추출하기 위한 활성 윤곽선 모델(Active Contour Model)을 제안한다. 제안된 모델에서 윤곽선은 레벨 함수 φ의 제로 레벨 집합으로 표현되고, 레벨 집합의 편미분 방정식을 통해 진화된다. 이 때, 제안된 모델에서는 윤곽선의 진화와 종교를 위해 2차원 가우시안 모델로 표현되는 피부색 정보를 이용한다. 이를 통해 잡음 및 다양한 포즈를 가지는 복잡한 영상에서도 정확한 얼굴 경계선을 얻을 수 있는 강건한 추출 방법이 구현된다. 제안된 방법의 유효성을 평가하기 위해서 다양한 영상에 대해서 실험이 이루어졌으며, 그 결과를 geodesic 활성 윤곽선 모델의 결과와 비교하였다. 실험결과는 제안된 방법의 보다 나은 성능을 보여준다.

가정방문물리치료가 국가유공자 재가장애인의 운동기능, 일상생활동작 수행 및 통증수준에 미치는 영향 (The Effects of Home Visiting Physical Therapy on the Motor Function, Activity of Daily Living, and Pain for Disabled Veterans)

  • 권춘숙;김선엽;장현정
    • 대한물리의학회지
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    • 제9권2호
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    • pp.171-179
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    • 2014
  • PURPOSE: The objectives of this study were to investigate the effects of physical therapy provided at home on the motor function, activity of daily living (ADL), and level of pain in veterans men with disabilities, and to provide the information. METHODS: The participants were 108 patients men with disabilities living in the cities Seoul, Pusan, Daegu, Gwangju and Daejeon; they performed physical therapy at home-provided by physical therapy services- that included therapeutic exercise for 50 minute, 1~2 times a week for 24 weeks. The motor function was measured by using motor assessment scale (MAS) and ADL, the level of pain were recorded both before and after physical therapy. The data form both before and after physical therapy were analyzed by using the paired t-test. All statistical tests in this study were performed with the level of significance set at .05. RESULTS: After 24 weeks of physical therapy, we observed significant improvement in the MAS and ADL scale, as well as significant decrease in the level fo pain in the participants (p<.01). Significant improvement was also observed in the MAS and ADL scale, as well as a decrease in the level of pain among participants with stroke and spinal disease (p<.05). CONCLUSION: The findings of this study show that physical therapy provided at home can lead to an improvement in the motor function as well as improved ADL and pain control; physical therapy also has positive effects in relieving symptoms of veterans with disabilities.

지역사회 재가노인의 인지기능과 관련요인 (Cognitive Function among the Elderly and Its Correlated Factors)

  • 민혜숙
    • 성인간호학회지
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    • 제19권1호
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    • pp.78-88
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    • 2007
  • Purpose: The purpose of this study was to find out the degree of cognitive function among the elderly and to confirm its correlated factors. Methods: The subjects consisted of 392 elderly people over the age 65 who were living in Busan. Data were collected by the interview method, using a structured questionnaire and the K-MMSE scale. Results: The average points of the elderly's cognitive functions measured by K-MMSE were 23.76(${\pm}4.02$). With the cut-off point for cognitive impairment set as 24 points below using K-MMSE scale, 38.8% of the subjects have cognitive impairments. Among the variables related to cognitive functions, literacy showed the highest correlation with cognitive function(${\beta}=.330$, t=7.249, p<.001), followed in order by educational level, age, depression level, attendance of elderly's college, and religious activity. The total explanatory power of these variables is 36%. Conclusion: In order to prevent cognitive impairment among the elderly, elderly people have to maintain social relationships continuously, and expand the social network by participating in the related programs. Some efforts to prevent the occurrence of depression and to stimulate patients' brain activity need to be recommended.

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단축형 ICF 핵심지표로 측정한 뇌졸중 환자의 기능상태 (Assessing the Functional Status of Acute Stroke Patients using ICF Core Set-short Form)

  • 강지연;공주;박미진;이여원;김유리
    • 근관절건강학회지
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    • 제20권1호
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    • pp.22-30
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    • 2013
  • Purpose: The International Classification of Functioning, Disability and Health (ICF) model was proposed by the World Health Organization for enhancing interdisciplinary communication. The purpose of this study was to examine the functional status of acute stroke patients using ICF core sets-short form. Methods: A set of 15 ICF items on functional status was used by nurses for their daily nursing assessment on functional status in 44 acute stroke patients in a university hospital. Results: The highest level of function was "consciousness", while the lowest was "defecation". Compared with functional status on the first day, consciousness, ingestion, language (mental), and defecation functions were significantly improved on the 14th day. However, there was no significant changes in items on activity and participation or environmental functions. Conclusion: These findings suggest that the function-specific nursing interventions for acute stroke patients need to be developed. Future research needs to test the usefulness of ICF items as an measurement tool.

A Statistical Perspective of Neural Networks for Imbalanced Data Problems

  • Oh, Sang-Hoon
    • International Journal of Contents
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    • 제7권3호
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    • pp.1-5
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    • 2011
  • It has been an interesting challenge to find a good classifier for imbalanced data, since it is pervasive but a difficult problem to solve. However, classifiers developed with the assumption of well-balanced class distributions show poor classification performance for the imbalanced data. Among many approaches to the imbalanced data problems, the algorithmic level approach is attractive because it can be applied to the other approaches such as data level or ensemble approaches. Especially, the error back-propagation algorithm using the target node method, which can change the amount of weight-updating with regards to the target node of each class, attains good performances in the imbalanced data problems. In this paper, we analyze the relationship between two optimal outputs of neural network classifier trained with the target node method. Also, the optimal relationship is compared with those of the other error function methods such as mean-squared error and the n-th order extension of cross-entropy error. The analyses are verified through simulations on a thyroid data set.

하이브리드 신경망을 이용한 실내(室內) 쾌적감성(快適感性)모형 개발 (Development of Comfort Feeling Structure in Indoor Environments Using Hybrid Neuralnetworks)

  • 전용웅;조암
    • 대한인간공학회지
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    • 제20권2호
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    • pp.29-46
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    • 2001
  • This study is about the modeling of comfort feeling structure in indoor environments. To represent the degree of practical comfort feeling level in an environment, we measured elements of human sense and resultant elements of comfort feeling such as coziness, refreshment, and freshness with physical values(temperature, illumination, noise. etc.). The relationships of elements of human sense and elements of comfort feeling were formulated as a fuzzy model. And a hybrid-neural network with three layers were designed where obtained from fuzzy membership function values of the elements of human sense were used as inputs, and given as fuzzy membership function values of resultant elements of comfort feeling were used as outputs. Both kinds of fuzzy membership function values were obtained from physical values. The network was trained by measured data set. The proposed hybrid-neural network were tested and proposed a more realistic model of comfort feeling structure in indoor environments.

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퍼지이론을 이용한 품질 정보 관리기법 개발에 관한 연구 (Development of Quality Information Control Technique using Fuzzy Theory)

  • 김경환;하성도
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1996년도 추계학술대회 논문집
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    • pp.524-528
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    • 1996
  • Quality information is known to have the characteristic of continuous distribution in many manufacturing processes. It is difficult to describe the process condition by classifying the distribution into discrete ranges which is based on the set concept. Fuzzy control chart has been developed for the control of linguistic data but it still utilizes the dichotomous notion of classical set theory. In this paper, the fuzzy sampling method is studied in order to manage the ambiguous data properly and incorporated for generating fuzzy control chart. The method is based on the fuzzy set concept and considered to be appropriate for the realization of a complete fuzzy control chart. The fuzzy control chart was compared with the conventional generalized p-chart in the sensitivity for quality distribution and robustiness against the noise. The fuzzy control chart with the fuzzy sampling method showed better characteristics.

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Photovoltaic System Allocation Using Discrete Particle Swarm Optimization with Multi-level Quantization

  • Song, Hwa-Chang;Diolata, Ryan;Joo, Young-Hoon
    • Journal of Electrical Engineering and Technology
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    • 제4권2호
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    • pp.185-193
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    • 2009
  • This paper presents a methodology for photovoltaic (PV) system allocation in distribution systems using a discrete particle swarm optimization (DPSO). The PV allocation problem is in the category of mixed integer nonlinear programming and its formulation may include multi-valued dis-crete variables. Thus, the PSO requires a scheme to deal with multi-valued discrete variables. This paper introduces a novel multi-level quantization scheme using a sigmoid function for discrete particle swarm optimization. The technique is employed to a standard PSO architecture; the same velocity update equation as in continuous versions of PSO is used but the particle's positions are updated in an alternative manner. The set of multi-level quantization is defined as integer multiples of powers-of-two terms to efficiently approximate the sigmoid function in transforming a particle's position into discrete values. A comparison with a genetic algorithm (GA) is performed to verify the quality of the solutions obtained.

청바지제품 세분시장 내 가격-품질 평가집단 추출에 관한 연구: 결합분석과 mixture model를 이용하여 (Market Segmentation With Price-Dependent Quality Evaluation in Denim Jeans Market ; Based on Conjoin analysis and mixture model)

  • 곽영식;이진화
    • 한국의류학회지
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    • 제26권11호
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    • pp.1605-1614
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    • 2002
  • The purpose of this study was to identify the consumers who use the level of price as the indicator of the product quality. In order to implement the purpose of this study, Jeans market had been segmented by the mixture regression model, and price response function was calibrated for each segment. Based on the types of price response function, segments were allocated into one of two groups; the group using the level of price as the quality indicator or the group not using the level of price as that. Then, characteristics of both groups were compared in terms of product attributes and demographic variables. Data were co]looted from the sample of the 23o undergraduate and graduate students in Seoul. For the data analysis, mixture regression model, conjoint analysis, and t-test were used. As a result, jeans market was divided into 5 segments. Segment 1,2,3 were allocated into the group not using the level of price as the quality indicator while segment 4,5 were done into the other group. Significant differences existed between two groups in product attributes, not in demographic variables. Mixture model and conjoint analysis were proved to be an effective set of tools in market segmentation.

컴퓨터 주의집중 프로그램이 혈관성 치매노인의 인지, 실행기능에 미치는 영향 (The Effects of Computer - based Attention Program on Cognition and Executive Function in Elderly with Vascular Dementia)

  • 이효정;황경옥
    • 대한통합의학회지
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    • 제2권2호
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    • pp.13-20
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    • 2014
  • Purpose : The purpose of this study was to evaluate the influence of cognition and executive function by computer - based attention program in vascular dementia. Method : The subjects of this study, old man diagnosed with vascular dementia, 12 patients were picked up, who were agreed with this research and were having hospital care for 4 weeks at nursing care centers. Computer-based attention program was applied to vascular dementia. Cognitive function measured by a K-MMSE and executive function measured by ACL. The SPSS Ver. 18.0 statistical program was used for data processing. The significance level for statistical inspection was set as 0.05. Result : In comparison of cognitive function was not significantly correlated in the pre and post test and executive function was significantly correlated in the pre and post test. Conclusion : Therefore, the computer-based attention program is useful to improve the cognitive and executive function in elderly with vascular dementia.