• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.355-358
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• 2005

Fingerprint recognition systems are the most widely used in biometrics for personal authentication. As they become more familiar, the security weaknesses of fingerprint sensors are becoming better known. In this paper, we propose a liveness detection method that applies correlation filter to the fingerprint recognition systems. The physiological characteristic of sweat pore, observed only in live people, is used as a measure to classify 'live' fingers from 'spoof' fingers. Previous works show that detection of sweat pores and perspiration patterns in fingerprint images can be used as an anti-spoofing measure. These methods don't consider the characteristic of pores in each individual. We construct the correlation filters of each individual which are composed of their pore information. We make the final decision about the "livens" of fingerprint using correlation output. The proposed algorithm was applied to a data set of 110 live, 110 spoof fingerprint images from optical fingerprint scanner and achieved classification rate of 80%.

• 대한간호학회지
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• 제40권2호
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• pp.236-246
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• 2010

Purpose: The purpose of this study was to develop and evaluate a Korean questionnaire to measure resilience in children with chronic illness. Methods: Item construction was drawn from an extensive review of the literature, existing questionnaires and interviews with parents. Content validity was tested by experts. To further refine the questionnaire and test its reliability and validity, data were collected from the 202 children with asthma, diabetes mellitus or nephrotic syndrome. Corrected items were used to total correlation coefficient and test-retest reliability. Questionnaire testing was conducted using factor analysis, Cronbach's $\alpha$, and correlation coefficients. Validity of the questionnaire was tested using internal consistency, construct validity, and criterion-related validity. Results: Components of the questionnaire were in three domains; interpersonal characteristics, characteristics of coping, and intrapersonal characteristics. Factor analysis is showed five factors; positive self-understanding, self-reliance, resourcefulness, perception of positive family relationships, and intimacy. The questionnaire showed a high internal consistency. A significant positive correlation with the Numerical Rating Score and negative correlation with the Child Depression Inventory support the validity of the questionnaire. Conclusion: This instrument demonstrated high reliability and validity. Therefore, this instrument can contribute to the evaluation of resilience of chronically ill children and to any subsequent intervention as well as to develop a theory for resilience.

• 한국소음진동공학회논문집
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• 제26권5호
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• pp.609-615
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• 2016

Measuring similarity between two signals is a key element of the location template matching (LTM) method which is one of impact source localization technique. As a measure of similarity, the correlation coefficient is most widely used, and the group delay based method is recently proposed to improve the accuracy of finding the impact source. In practice, the LTM method assumes that the similarity between two signals decreases as the distance between two corresponding impact points increases, where the distance between two neighboring impact points defines the grid spacing. In this paper, it is shown that this assumption is not always true but the correlation coefficients fluctuate forming a main robe and many side robes as the distance between two neighboring impact points increases. On the other hand, the standard deviation of group delay sharply increases with a small increase of the grid spacing. These are demonstrated by using a simple cantilever beam. Based on these findings, an optimal way of implementing the LTM method may be suggested by combining the correlation coefficient and the group delay based approaches.

• 한국콘텐츠학회논문지
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• 제9권9호
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• pp.287-294
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• 2009

연구를 통하여 뇌졸중 환자에서 알렌인지수준과 인지기능, 일상생활활동 및 상지기능과의 상관관계를 분석하고자 하였다. 연구 대상자는 뇌졸중 환자 38명으로 인지기능은 알렌인지주순검사(Allen Cognitive Level Test) 와 한국형 간이 정신상태검사(Mini-Mental Screening Exam-Korea)로, 일상생활활동은 기능적독립성측정(Functional Independence Measure)로, 뇌졸중 상기 기능은 뇌졸중 상지기능검사(Manual Function Test)로 검사하였다. 피어슨 상관관계 분석을 이용하여 상관관계를 분석하였다. 알렌인지수준과 한국형 간이정신상태검사, 기능적독립측정, 뇌졸중 상기기능검사 간에 상관관계가 유의하였다(p<.05). 본 연구에서는 알렌인지수준 검사와 일상생활활동과의 상관성 및 인지평가도구로서의 유용성을 제시하였고 편마비 환자 적용에 있어 문제의 가능성과 이에 따른 연구 필요성을 제기하였다.

• 임상간호연구
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• 제15권2호
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• pp.127-138
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• 2009

Purpose: The purpose of this study was to explore self-reported perceived stigma, self-efficacy, and quality of life among psychiatric outpatients Methods: In the present study, researchers analyzed the survey responses of 195 patients recruited in the S hospital psychiatry outpatient clinic. The measurement tools used in this study were the "Devaluation & Discrimination" scale to determine perceptions of stigmatization, general and social efficacy scales to measure self-efficacy, and the "General Well-Being Index" to measure quality of life in psychiatric outpatient. Statistical analysis included means with standard deviation, t-test, ANOVA and Pearson correlation coefficients to identify relationships between the variables. Results: There was a significant difference in self-perceived stigma and quality of life in psychiatric outpatients (r=-.233, p=.001) and a negative correlation between self-efficacy and quality of life (r=-.424, p=.000). Correlation analysis results support the hypothesis that higher self-perceived stigma scores were related to reduced quality of life among patients with schizophrenia (r=-.231, p=.021), while there was a positive correlation between self-perceived stigma scores and self-efficacy scores among patients with bipolar disorder (r=.362, p=.013). Conclusion: The findings suggest that nursing imtervention strategies should include education programs to reduce stigmatization and enhance self-efficacy and quality of life among patients with chronic psychiatric illnesses.

• 한국정보통신학회논문지
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• 제17권7호
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• pp.1564-1570
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• 2013

이 논문에서는 rank order 필터와 상호상관을 이용하여 강인하게 눈동자를 찾는 방법을 제안한다. rank order 필터를 사용하여 얼굴 영상에서 눈동자 후보점을 찾는다. 임계치를 변화하며 눈 영역을 이진화하여 눈썹 위치를 구한 후 눈썹 영역의 눈동자 후보점을 제거한다. 눈동자 위치를 보정한 후 두 눈동자 후보점을 기하학적인 제약조건을 기반으로 쌍으로 묶는다. 각 쌍의 두 눈에 대한 유사도를 상호상관을 이용하여 측정하여 가장 큰 값을 갖는 쌍을 최종 눈동자로 결정한다. BioID 얼굴 데이터베이스의 얼굴 영상 500개에 대한 실험 결과 96.8%의 높은 눈동자 검출율을 보였으며 기존 방법보다 약 11.6% 개선된 결과를 얻었다.

• PNF and Movement
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• 제17권2호
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• pp.329-337
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• 2019

Purpose: Ultrasound imaging is commonly used to measure the pennation angle of human skeletal muscles in vivo. However, manual assessment of the pennation angle using ultrasound images is subjective and time-consuming and requires a high level of examiner skill. The architectural analysis of human skeletal muscles is thus challenging. Automated approaches using image processing techniques are therefore required to estimate the pennation angle in ultrasound images. The purpose of this study was thus to assess the intra-tester and inter-tester reliability and validity of the pennation angle using an automatic measurement program. Methods: Twenty-two healthy young adults (mean age = 22.55 years) with no medical history of neurological or musculoskeletal disorders voluntarily participated in this study. Ultrasound imaging was used to measure the pennation angle of the gastrocnemius muscle at rest. One examiner acquired images from all the participants. The intra-tester and inter-tester reliability were evaluated using the intraclass correlation coefficient (ICC) to estimate reliability. Validity was measured using Pearson's correlation coefficient. Results: The intra-rater reliability was excellent for the automatic pennation angle measuring program and the manual pennation angle assessment method (ICC>0.95). The inter-rater reliability was also excellent for both methods (ICC>0.93). All the correlation coefficients for the automatic pennation angle measuring program and the manual pennation angle assessment method were 0.79, which indicated a significantly positive correlation (p<0.05). Conclusion: Pennation angle measurement using the automatic pennation angle measuring program showed acceptable reliability and validity. This study therefore demonstrated that the automatic measuring program was able to automatically measure the pennation angle of skeletal muscles using ultrasound images, and thus made it easy to investigate skeletal muscle architecture.

• Nuclear Engineering and Technology
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• 제52권1호
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• pp.192-205
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• 2020

Seismic design practices and seismic response analyses of civil structures and nuclear power plants (NPPs) have conventionally used the peak ground acceleration (PGA) or spectral acceleration (S_a) as an intensity measure (IM) of an earthquake. However, there are many other earthquake IMs that were proposed by various researchers. The aim of this study is to investigate the correlation between seismic responses of NPP components and 23 earthquake IMs and identify the best IMs for correlating with damage of NPP structures. Particularly, low- and high-frequency ground motion records are separately accounted in correlation analyses. An advanced power reactor NPP in Korea, APR1400, is selected for numerical analyses where containment and auxiliary buildings are modeled using SAP2000. Floor displacements and accelerations are monitored for the non- and base-isolated NPP structures while shear deformations of the base isolator are additionally monitored for the base-isolated NPP. A series of Pearson's correlation coefficients are calculated to recognize the correlation between each of the 23 earthquake IMs and responses of NPP structures. The numerical results demonstrate that there is a significant difference in the correlation between earthquake IMs and seismic responses of non-isolated NPP structures considering low- and high-frequency ground motion groups. Meanwhile, a trivial discrepancy of the correlation is observed in the case of the base-isolated NPP subjected to the two groups of ground motions. Moreover, a selection of PGA or S_a for seismic response analyses of NPP structures in the high-frequency seismic regions may not be the best option. Additionally, a set of fragility curves are thereafter developed for the base-isolated NPP based on the shear deformation of lead rubber bearing (LRB) with respect to the strongly correlated IMs. The results reveal that the probability of damage to the structure is higher for low-frequency earthquakes compared with that of high-frequency ground motions.

• 대한물리의학회지
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• 제17권3호
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• pp.51-58
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• 2022

PURPOSE: This study aimed to evaluate the correlation between executive function and gait evaluations for the elderly, and validate the obstacle gait evaluation as a cognitive impairment test tool. METHODS: This study was a cross-sectional design. 79 people aged 65 years or older were selected as subjects. The Korean version of the Mini-Mental State Examination (MMSE-KC) to evaluate overall cognitive function and the Trail Making Test (TMT) A, B to measure executive function were performed. The 4-meter walking speed test and the walking speed test while crossing over an obstacle were carried out to evaluate gait. The Spearman's correlation was used to measure the correlation between cognition and gait speed. RESULTS: There was no significant correlation between the 4 m gait speed and executive function( TMT-A (p = .056), TMT-B (p = .115)). However, there was a significant correlation between the 4 m gait speed and MMSE-KC (r = .277, p < .05). There was also a significant correlation between walking speed while crossing over an obstacle and all tests (MMSE-KC (r = .382, p < .01). TMT-A (r = -.327, p < .01), TMT-B (r = -.283, p < .05)). CONCLUSION: It was found that the gait speed while crossing over an obstacle was correlated with all cognitive function tests. Therefore, we suggest the use of the gait speed test while crossing over an obstacle rather than the simple gait test to diagnose cognitive decline.

• 한국치위생학회지
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• 제12권2호
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• pp.345-353
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• 2012

Objectives : The author has studied about correlation of gingival exposure upon smiling and oral facial status that reduce facial aesthetic. Methods : The subjects in this study are 91 female vulunteers who were in aged $21.4{\pm}1.89$ in Suwon. Objectives should be normal oral and facial status without the prosthodontic, orthodontic appliance or conqenital missing tooth, and agree to be examined the oral status and impression taking. 1.Measure the length of gingival exposure upon smiling. 2.Measure of the size on central incisor. 3.Measure of Facial. SPSS(SPSS 10.0 for windows, SPSS Inc, Chicago, USA) was utilized for calculating the correlation coefficient between gingival exposure upon smiling and facial status. Regression analysis was calculated in order to predict the R square for gingival exposure upon smiling. Results : 1.Correlation coefficient between the gingival exposure and length of maxillary central incisor was calculated as reversed correlation(r=-.302, p<0.01), and between the gingival exposure and the ratio of the length of central incisor/width of central incisor was revealed as reversed correlation(r=-.250, p<0.05) on smiling. 2.There was correlation between the gingival exposure and the facial height(r=.351, p<0.01), the lower facial height(r=.454, p<0.01) and the upper lip height(r=.274, p<0.01) upon smiling. 3.There was correlation between the gingival exposure and the ratio of the facial height/facial width(r=.358, p<0.05), the ratio of the upper facial height/facial width(r=.214, p<0.05), and the ratio of the lower facial height/facial height(r=.383, p<0.01) upon smiling. 4.The equation of the regression analysis for gingival exposure upon smiling could be estimated as gingival exposure upon smiling=-5.139+.279${\times}$lower facial height-.615${\times}$maxillary central incisal length-.05${\times}$nasolabial angle. Conclusions : Considering these results, it recommended that treatment planning should be designed in consideration of such factors as the length of maxillary central incisor, facial height, upper lip height and lower facial height, in order to promote the easthetic problems of face on smiling.