• 대한물리의학회지
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• 제15권3호
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• pp.99-108
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• 2020

PURPOSE: This study examined the effects of the confusion level in performing dual tasks using smartphones while walking in subjects with chronic ankle instability (CAI). METHODS: Twenty subjects with CAI and 20 healthy subjects participated in the study. The spatial, temporal, spatial-temporal, and variability gait parameters were measured using GAITRite under four different conditions: general gait, web surfing during gait, texting during gait, and gaming during gait. Two-way repeated-measures analysis of variance was used to analyze the interaction according to the group (2) and confusion level in dual-tasks (4). One-way repeated-measures analysis of variance was used to compare the changes within the group according to the confusion level in dual-tasks. The changes between groups were compared using an independent t-test. The statistical significance level was set to p = .05. RESULTS: Significant interactions in the temporal and spatial-temporal gait parameters were found between the dual-task conditions and the other groups (p < .05). Significant within-group differences in the spatial, temporal, and spatial-temporal gait parameters were found according to the confusion level in dual tasks (p < .05). Significant between-group differences were observed in the temporal and spatial-temporal gait parameters according to the confusion level in dual tasks (p < .05). CONCLUSION: The effect of the confusion level in dual tasks was greater in subjects with CAI than in healthy individuals. This study suggests that to prevent reinjury to the ankle, subjects with CAI should avoid dual tasks such as using smartphones while walking.

• IEIE Transactions on Smart Processing and Computing
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• 제6권2호
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• pp.76-84
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• 2017

This paper presents an efficient method for generating spatiotemporal images in order to detect leukocyte motion in microvessels. Leveraging the constraint that leukocytes move along the contour line of the blood vessel wall, our proposed method efficiently generates spatiotemporal images for leukocyte motion detection. To that end, translational motion caused by in vivo movement is first removed by a template matching method. Second, the blood vessel region is detected by an automatic threshold selection method in order to binarize temporal variance images. Then, the contour of the blood vessel wall is expressed via B-spline function. Finally, using the detected blood vessel wall's contour as an initial curve, the plasma layer for the most accurate position is determined in order to find the spatial axis via snake, and the spatiotemporal images are generated. Experimental results show that the spatiotemporal images are generated effectively through comparison of each step with three images.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2009년도 학술발표회 초록집
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• pp.1260-1264
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• 2009

Precipitation time series is a mixture of complicate fluctuation and changes. The monthly precipitation data of 61 stations during 36 years (1973-2008) in Korea are comprehensively analyzed using the EOFs technique and CSEOFs technique respectively. The main motivation for employing this technique in the present study is to investigate the physical processes associated with the evolution of the precipitation from observation data. The twenty-five leading EOF modes account for 98.05% of the total monthly variance, and the first two modes account for 83.68% of total variation. The first mode exhibits traditional spatial pattern with annual cycle of corresponding PC time series and second mode shows strong North South gradient. In CSEOF analysis, the twenty-five leading CSEOF modes account for 98.58% of the total monthly variance, and the first two modes account for 78.69% of total variation, these first two patterns' spatial distribution show monthly spatial variation. The corresponding mode's PC time series reveals the annual cycle on a monthly time scale and long-term fluctuation and first mode's PC time series shows increasing linear trend which represents that spatial and temporal variability of first mode pattern has strengthened. Compared with the EOFs analysis, the CSEOFs analysis preferably exhibits the spatial distribution and temporal evolution characteristics and variability of Korean historical precipitation.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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• pp.118-121
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• 2006

Variations in the extent and dispersal of river plume are important in the study of coastal environment. The objectives of this study are to examine relationship between satellite detected plume area and river discharge and to clarify the temporal and spatial dynamic of plume from Tokachi River, Hokaido, Japan. We used 1.1 km spatial resolution of SeaWiFS normalized water-leaving radiance (nLw) images from 1998 to 2002. Supervised maximum likelihood classification was implemented to define classes of surface water optical properties. Satellite observed plume area was correlated to the amount of river discharge from April to October. First mode (44% of variance) of EOF analysis shows the turbid plume distribution resulting from re-suspension by strong wind mixing along the coast during winter. This mode also shows plume distribution along-shelf direction in spring and late summer. Second mode (17% of variance) shows spring pattern across-shelf direction due to strong discharge of snow melting water.

• 국제물리치료학회지
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• 제6권2호
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• pp.840-845
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• 2015

Improvement in functional gait is one of treatment goals in treatment of cerebral palsy children. This study intended to examine the effects of insoles for postural correction on gait in spastic cerebral palsy patients by investigating changes in gait temporal spatial parameters. As the subjects, 15 spastic bilateral cerebral palsy patients participated in this study. Temporal spatial parameters of gait were measured using GAITRite system under three gait conditions. Bare foot gait, gait in shoes, and gait in insoles for postural correction were conducted. In order to look at differences in temporal spatial parameters according to three gait conditions, repeated one way analysis of variance was conducted. As post hoc test, Bonferroni was conducted. A significant level was set at ${\alpha}=.05$. According to the result of this study, gait velocity, cadence, step length, stride length of the left lower extremity significantly changed. When the subjects put on customized insoles for postural correction, the effect was greatest. There were no significant changes in stance time, single support time, double support time, swing % of gait, and stance % of cycle. Therefore, gait with insoles for postural correction positively influenced functional gait improvement and will be able to be usefully employed for spastic cerebral palsy children as one of gait assistance devices.

• 한국해양학회지
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• 제21권4호
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• pp.193-202
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• 1986

황해 동남해역에서 해면과 30m층 수온의 시. 공간 변동성을 1967-1982 장기 수온자료의 variance 와 cmpirical orthogonal function(EOF)분석으로 연구하였다. 월평균 해면수온의 공간분포는, 남에서 북으로 감소하는 장기 년평균과 유사한 형태를 갖고 있다. 반면에 년평균 해면수온으로부터 계산한 분산은 남에서 북으로 증가한다. 해면 수온의 variance 가 경기만 남부해역을 제외한 연구해역에서 30m층 보다 2배이상 크다. EOF의 첫째와 둘째 모드가 계절변화를 갖고 있으며 해면과 30M층 variance의 97.6%와 85.2%를 각각설명하기 때문에 수온의 큰 variance 는 계절변화와 밀접한 관계가 있다. 겨울철 조사 해역 북부와 남부사이 수온의 차이가 크나 여름철에는 작아진다. 이것은 여름철 복사에 의한 해면의 열흡수가 열손실이 나 해양열이류보다 훨씬 크다는 것을 반영해준다. 여름철에 경기만 남부와 목포 주변 연안수가 조석혼합에 의해 외해수보다 수온이 낮게 나타난다.

• 한국통신학회논문지
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• 제32권5C호
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• pp.520-529
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• 2007

본 논문에서는 웨이블릿 변환 기반 스케일러블 비디오 부호화에서 가장 중요한 요소 기술인 움직임 보상 시간적 필터링 방법의 성능에 관련된 요소들의 특성을 파악하고, 기존의 DCT 기반의 하이브리드 부호화에서 사용된 움직임 예측 방법과 가변 크기 블록을 사용한 움직임 예측 방법을 적용한 향상된 MCTF (Motion Compensated Temporal Filtering) 방법을 제안한다. 이를 통하여 시간적 필터링 과정에서의 연결성을 높이고, 프레임간 에너지를 저/고주파 프레임으로 효율적으로 분해할 수 있다. 그 결과, 고주파 프레임의 에너지를 줄여, 엔트로피 부호화 비트율을 줄일 수 있다. 본 논문에서 제안하는 방법을 적용하여 모의 실험한 결과, 고주파 프레임에 포함된 에너지가 최대 25.86%까지 감소하는 것을 확인하였다.

• 대한원격탐사학회지
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• 제21권3호
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• pp.213-219
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• 2005

In the Korean seas, Sea Surface Temperature (SST) and Thermal ronts (TF) were analyzed temporally and spatially during 8 years from 1993 to 2000 using NOAA/AVHRR MCSST. In the application of EOF analysis for SST, the variance of the 1st mode was 97.6%. Temporal components showed annual variations, and spatial components showed that where it is closer to continents, the SST variations are higher. Temporal components of the 2nd mode presented higher values of 1993, 94 and 95 than those of other years. Although these phenomena were not remarkable, they could be considered ELNI . NO effects to the Korean seas as the time was when ELNI . NO occurred. The Sobel Edge Detection Method (SEDM) delineated four fronts: the Subpolar Front (SPF) separating the northern and southern parts of the East Sea; the Kuroshio Front (KF) in the East China Sea, the South Sea Coastal Front (SSCF) in the South Sea, and the Tidal Front (TDF) in the West Sea. TF generally occurred over steep bathymetry slopes, and spatial components of the 1st mode in SST were bounded within these frontal areas. EOF analysis of SST gradient values revealed the temporal and spatial variations of the TF. The SPF and SSCF were most intense in March and October; the KF was most significant in March and May.

• 방송공학회논문지
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• 제10권4호통권29호
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• pp.463-473
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• 2005

본 논문에서는 JVT에서 표준화가 진행중인 스케일러블 동영상 부호화의 부호화 효율을 높이기 위해 영상 시퀀스의 시간적변환 특성을 고려하여 적응적으로 GOP의 크기를 선택하여 부호화를 하는 방법을 제안한다. 일반적으로 SVC에서는 한 영상 시퀀스에 대해서 GOP의 크기를 고정하여 부호화를 하는데, GOP의 크기와 영상 시퀀스의 시간적 특성에 따라 부호화 효율이 변하게 된다. 이에 비디오 시퀀스의 지역적인 시간적 특성에 따라 GOP의 크기를 적응적으로 가변 하여 부호화하는 방식을 제안한다. 실험 결과 제안된 적응적 GOP 구조 (Adaptive GOP Structure) 부호화 방법의 부호화 효율이 개선되었으며, Crew 시퀀스에서는 0.63dB 가 향상되었다.

• 대한물리의학회지
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• 제15권3호
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• pp.117-125
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• 2020

PURPOSE: Aging causes changes in the postural alignment and gait due to changes in the nervous and musculoskeletal systems. On the other hand, the relationship between the changes in posture alignment and gait is unclear. This study examined the relationship between the postural alignment and spatiotemporal gait parameters in Korean elderly women. METHODS: Thirty-two-healthy elderly women participated in this study. All subjects were assessed for their posture alignment and gait ability. Stepwise multiple linear regression was performed to determine to what extent the postural alignments could explain the spatiotemporal gait parameters. RESULTS: Coronal head angle was moderately correlated with the velocity (r = -.51), normalized velocity (r = -.46) and gait-stability ratio (r = .58) (p < .05). The trunk angle was moderately correlated with the normalized velocity (r = -.32) and gait-stability ratio (r = .32) and weakly correlated with the velocity (r = -.28) (p < .05). The coronal shoulder angle was moderately correlated with the swing phase (r = -.57), stance phase (r = .56), single limb stance (r = -.56) and double limb stance (r = .51) (p < .05). The coronal head angle and trunk angle accounted for 36% of the variance in velocity, 33% variance in normalized velocity and 46% variance in the gait-stability ratio (p < .05). The coronal shoulder angle accounted for 32% variance in the swing phase, 32% variance in the stance phase, 31% variance in the single limb stance and 26% variance in the double limb stance (p < .05). CONCLUSION: Changes in posture alignment in elderly women may serve as a biomarker to predict a decrease in walking ability due to physical aging.