• 국제물리치료학회지
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• 제5권1호
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• pp.652-660
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• 2014

In the present study, to examine the effects of somatosensory stimulation of the hands on the hand functions and visuomotor coordination of children with developmental disabilities, a total of 24 sessions of experiments were conducted with three children with developmental disabilities for 60 minutes per session, three sessions per week from January 7, 2013 to March 11, 2013. To examine the effects of somatosensory stimulation of the hands on grasping and visuomotor coordination which are sub-areas of PDMS-2, the A-B study design was used which is a single case study method out of single-subject experimental research designs. Somatosensory stimulation of the hands was shown to be effective in improving the hand functions of children with developmental disabilities. Somatosensory stimulation of the hands showed positive effects on the raw scores and standardized scores of grasping and visuomotor coordination in all the three subject children. Visuomotor coordination functions showed higher scores in post-hoc tests in all three children. In particular, ring throws showed high scores at right $90^{\circ}$, right $45^{\circ}$, center, left $45^{\circ}$, and left $90^{\circ}$ among visual directions. In the present study conducted with children with developmental disabilities, ring throws were performed to examine visuomotor coordination. In particular, the numbers of successes of ring throws on the front, left, and right were shown to be high. Therefore, somatosensory stimulation of the hands was effective on the hand functions and visuomotor coordination functions of children with developmental disabilities.

• 대한감각통합치료학회지
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• 제19권2호
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• pp.36-45
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• 2021

목적 : 본 연구는 발달지연의 아동을 대상으로 과제지향의 중재를 사용하여 시-운동 협응과 소운동 협응 기능의 변화를 알아보고자 하였다. 연구방법 : 연구대상은 6세의 여아 1명이었다. 아동은 진단은 받지 않았으나 전반적인 기능에 발달지연을 보였다. 연구기간은 2021년 2월 5일부터 6월 4일까지이었고, 연구 설계는 단일대상연구 A-B를 사용하였다. 기초선 A는 초기 3회기로 아동의 기능 파악을 위해 초기평가를 하였다. 중재기 B는 12회기로 과제지향의 중재(task-oriented intervention)를 사용하였다. 기초선과 중재기에 동일하게 아동의 시-운동 협응 기능을 측정하기 위해 한국판 시지각발달검사 3판의 타원그리기를 실시하였고, 소운동 협응 기능을 측정하기 위해 Clinical Observation of Motor and Postural Skills(COMPS)의 손가락-코 짚기를 실시하였다. 회기별 변화도는 그림으로 제시하였다. 결과 : 한국판 시지각발달검사 3판의 타원그리기의 기초선 평균은 23점이었고, 중재기 평균은 39.66점으로 기초선에 비해 중재기의 평균이 16점 이상 향상되었다. COMPS의 손가락-코 짚기의 기초선 평균은 0점이었고, 중재기 평균은 5.08점으로 기초선에 비해 중재기의 평균이 5점 이상 향상되었다. 결론 : 취학 전의 발달지연아동에게 과제지향의 중재는 아동의 학습에 바탕이 되는 시-운동 협응과 소운동 협응 기능에 긍정적인 영향을 미치는 것으로 보인다.

• The Journal of Korean Physical Therapy
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• 제26권6호
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• pp.386-390
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• 2014

Purpose: We aimed to investigate whether visuomotor function would be modulated, when healthy subjects performed tracking task after tDCS application over the primary sensorimotor cortex (SM1) in the non-dominant hemisphere. Methods: Thirty four right-handed healthy participants were enrolled, who randomly and evenly divided into two groups, real tDCS group and sham control group. Direct current with intensity of 1 mA was delivered over SM1 for 15 minutes. After tDCS, tracking task was measured, and their performance was calculated by an accuracy index (AI). Results: No significant difference in AI at the baseline between the two groups was observed. The AI of the real tDCS group was significantly increased after electrical stimulation, compared to the sham control group. Two way ANOVA with repeated measurement showed a significant finding in a large main effects of time and group-by-repeated test interaction. Conclusion: This study indicated that application of the anodal tDCS over the SM1 could facilitate higher visuomotor coordination, compared to sham tDCS group. These findings suggest possibility that tDCS can be used as adjuvant brain modulator for improvement of motor accuracy in healthy individuals as well as patients with brain injury.

• 한국컴퓨터그래픽스학회논문지
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• 제28권3호
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• pp.1-11
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• 2022

'실제 신체가 아닌 대상이 내 신체처럼 느껴지는 환상'을 의미하는 몸 소유감 환상 (Body Ownership Illusion; BOI)은 고무 손 환상 (Rubber-Hand Illusion) 실험에서 사람이 고무손을 자신의 손처럼 느낄 수 있다는 것을 보여준 뒤로 활발히 연구되어 왔으며, 가상 현실에서도 가상 신체에 대해 BOI가 형성될 수 있다는 것이 증명되었다. BOI의 형성을 위해 주로 사용된 Visuomotor(VM; 시각-운동), Visuotactile(VT; 시각-촉각) 자극이 어떤 영향을 미치는지 많은 연구가 되어왔으나 두 자극을 동시에 전신에 전달한 연구는 매우 제한적이었다. 본 연구에서는 가상 아바타와의 전신 몸 소유감에서 VM, VT 자극을 동시에 전달했을 때 각 자극이 BOI에 어떤 영향을 미치는지 연구하였고 추가적으로 임장감, 감정, 가상 멀미감으로 나타나는 사용자 경험을 연구하였다. 연구결과 BOI 측정 결과는 VM 측면에서는 자극이 일치할 때 높게 나타났으나 VT의 경우는 유의미한 차이가 나타나지 않았다. 임장감의 경우 VT는 VM이 일치하는 경우에서만 영향을 주는 것을 확인하였으며, 감정의 경우 정서가 정도에서 VM과 VT 자극이 모두 영향을 주고, 가상 멀미감의 경우 통계적인 차이를 확인하지 못하였다. 이러한 연구 결과는 가상 아바타와의 전신 몸 소유감에서 전반적으로 VM의 일치도가 중요한 요인이지만, VM이 일치되는 경우 VT의 일치가 임장감과 같은 주관적 경험에 영향을 줌을 시사한다.

• The Journal of Korean Physical Therapy
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• 제22권6호
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• pp.43-51
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• 2010

Purpose: This study examined the influence of visuomotor congruency on learning a relative phase relationship between a single joint movement and an external signal. Methods: Participants (N=5) were required to rhythmically coordinate elbow flexion-extension movements with a continuous sinusoidal wave (0.375 Hz) at a $90^{\circ}$ relative phase relationship. The congruent group was provided online feedback in which the elbow angle decreased (corresponding to elbow flexion) as the angle trajectory was movingup, and vice versa. The incongruent group was provided online feedback in which the elbow angle decreased as the angle trajectory was moving down, and vice versa. There were two practice sessions (day 1 and 2) and each session consisted of 6 trials per block (5 blocks per session). Retention tests were performed 24 hours after session 2, and only the external sinusoidal wave was provided. Repeated ANOVAs were used for statistical analysis. Results: During practice, the congruent group was significantly less variable than the incongruent group. Phase variability in the incongruent group did not significantly change across blocks, while variability decreased significantly in the congruent group. In retention, the congruent group produced the required $90^{\circ}$ relative phase pattern with significantly less phase variability than the incongruent group. Conclusions: Congruent visual feedback facilitates learning. Moreover, the deprivation of online feedback does not affect the congruent group but does affect the incongruent group in retention.

• 한국동물학회지
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• 제33권3호
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• pp.247-254
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• 1990

GABA antagonist 를 닭의 열린 눈과 닫힌 눈에 차례로 주입한 후 monocular head와 eye optokinetic nystagmus을 관찰하고 코일 기록에 의해서 연구하였다. 주입전 이 visuomotor reflex를 일으키는데 있어서 닭은 N-T 자극에 대해서 보다 T-N 자극에 대해서 더욱 효과적인 OKN을 나타냈다. 열린눈에 주입한 GABA antagonist는 head와 eye OKN의 감소 또는 소멸을 일으키며, GABA antagonist를 닫힌 눈속에 주입했을 때는 head와 eye OKN은 증가 되었다. 이와 같이 GABA antagonist는 monocular OKN의 N-T 성분을 억제하는데 GABAergic 메카니즘이 관련되고 있다는 것을 지시함으로써 head와 eye OKN의 방향적 불균형성을 제거하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권8호
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• pp.4241-4254
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• 2019

The efficiency and accuracy of handwriting measurement could be improved by adopting digital image processing. This study developed a computer-based Korean Handwriting Assessment tool. Second graders participated in this study by performing writing tasks of consonants, vowels, words, and sentences. We extracted boundary parameters for each letter using digital image processing and calculated the variables of size, size coefficient of variation (CV), misalignment, inter-letter space, inter-word space, and ratio of inter-letter space to inter-word space. Children were also administered traditional handwriting and visuomotor tests. Digital variables from image processing were correlated with these previous tests. Using these correlations, we established a three-point scoring system that computed test scores for each variable. We analyzed inter-rater reliability between the computer rater and human rater and test-retest reliability between the first and second performances. The validity was examined by analyzing the relationship between the Korean Handwriting Assessment and previous handwriting and visuomotor tests. We suggested the Korean Handwriting Assessment to measure size, size consistency, misalignment, inter-letter space, inter-word space, and space ratio using digital image processing. This Korean Handwriting Assessment tool proved to have reliability and validity. It is expected to be useful for assessing children's handwriting.

• 로봇학회논문지
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• 제14권1호
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• pp.40-49
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• 2019

Reinforcement learning has been applied to various problems in robotics. However, it was still hard to train complex robotic manipulation tasks since there is a few models which can be applicable to general tasks. Such general models require a lot of training episodes. In these reasons, deep neural networks which have shown to be good function approximators have not been actively used for robot manipulation task. Recently, some of these challenges are solved by a set of methods, such as Guided Policy Search, which guide or limit search directions while training of a deep neural network based policy model. These frameworks are already applied to a humanoid robot, PR2. However, in robotics, it is not trivial to adjust existing algorithms designed for one robot to another robot. In this paper, we present our implementation of Guided Policy Search to the robotic arms of the Baxter Research Robot. To meet the goals and needs of the project, we build on an existing implementation of Baxter Agent class for the Guided Policy Search algorithm code using the built-in Python interface. This work is expected to play an important role in popularizing robot manipulation reinforcement learning methods on cost-effective robot platforms.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 2001년도 춘계학술대회 논문집
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• pp.6-9
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• 2001

집중도를 평가하기 위하여 피험자에게 집중을 유발시키는 3가지 task(단기기억작업, Corsi block tapping task, visuomotor task)를 부가하고 주관평가 및 생리신호(뇌파, 심전도, 맥파, 피부온도, 호흡, 피부전도도)를 측정하였다. 뇌파를 mapping하여 평가에 적합한 전극이 위치를 선정하고, task 수행중 집중도 변화와 짐전도의 심박변화와의 관계를 분석하였다. 분석결과 안정과 task 수행시 뇌파 mapping상 전체 power의 변호가 frontal 부분에서 크게 나타났으며, 집중시 R-R 간격의 순간간격변화가 줄어들었다.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2011년도 한국컴퓨터종합학술대회논문집 Vol.38 No.1(C)
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• pp.393-396
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• 2011

In this paper, we propose a constrained alternating least squares nonnegative matrix factorization algorithm (cALSNMF) to detect active brain regions from single subject's task-related fMRI data. In cALSNMF, we define a new cost function which considers the uncorrelation and noisy problems of fMRI data by adding decorrelation and smoothing constraints in original Euclidean distance cost function. We also generate a novel training procedure by modifying the update rules and combining with optimal brain surgeon (OBS) algorithm. The experimental results on visuomotor task fMRI data show that our cALSNMF fits fMRI data better than original ALSNMF in detecting task-related brain activation from single subject's fMRI data.