• The Transactions of the Korean Institute of Power Electronics
• /
• v.7 no.6
• /
• pp.546-553
• /
• 2002

A control of the body posture and movement is maintained by the vestibular system, vision, and proprioceptors. Especially, vestibular system has a very important function that controls the eye movement through vestibuloocular reflex and contraction of skeletal muscles through vestibulospinal reflex. However, postural disturbance caused by loss of vestibular function results in nausea, vomiting, vertigo and loss of craving for life. Lose of vestibular function leads to abnormal reflex of eye movements named nystagmus. Analysis of the nystagmus is needed to diagnose the vertigo, which is performed by means of electrooculography(EOG). The purpose of this study is to develop a computerized system for data processing and an algorithm for the automatic evaluation of the slow component velocity(SCV) of nystagmus induced by optokinetic(OKN) stimulation system. A new algorithm using recursive least square method(RLSM) to detect SCV of nystagmus is suggested in this paper. This method allows a fast and precise evaluation of the nystagmus, through artifact rejection techniques. The results are depicted in this paper.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.39 no.3
• /
• pp.215-221
• /
• 2015

The elbow reflex, a principal reflex in the upper extremity, plays an important role in the diagnosis of cervical spine syndromes. In this study, the muscle activations of brachial biceps and triceps, and the kinematics of upper extremities were predicted using an activation model for the stretch reflex. The muscle activations that equated the simulation results estimated by the analysis model with the experimental results were obtained first, and the activations obtained from the simulations were compared with the electromyography signals obtained from the experiments, for model validation. The root mean squares error of the joint angles (obtained from experiments and simulation using the suggested model) was 0.056, a value that is half of that obtained using the previous model. This demonstrates that the suggested model corresponded well with the actual reflex.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
• /
• 1991.07a
• /
• pp.30-35
• /
• 1991

해저가 완만하게 변하는 해역 위를 지나는 파랑의 반사는 무시할 수 있으며 이에 대한 파랑계산 방법으로는 굴절 모델 (서 등, 1989)과 포물형 근사식 모델(서, 1990b)을 들 수 있다. 그러나 해저의 변화가 심해 상당량의 파랑에너지가 반사되는 경우에는 파랑 운동을 지배하는 원시 방정식인 Laplace을 사용하여야 한다.(중략)

• Nuclear Engineering and Technology
• /
• v.19 no.3
• /
• pp.192-197
• /
• 1987

Two-point kinetic equations for a compact-core-with-bulky-D$_2$O-reflector system were developed. A unique feature of the system is that certain fission gammas create retarded photoneutrons in the D$_2$O reflector by (ｒ, n) reaction. Coupling effect between the core and the reflector was investigated by simulating power transients with various ramp reactivity insertions. Special attention was paid to the phenomenon associated with spatial separation of photoneutrons and their precursors. Simulations show that accuracy of the two-point model is comparable with that of space-dependent approach. Also it is found that the explicily expressed photoneutron terms in the reflector equation slow down the power transient compared to non-photoneutron expressions. Detectors for reactor power control purpose prefer to be deployed in the core zone to be able to accurately perdict transient power.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
• /
• v.3 no.1
• /
• pp.14-25
• /
• 1992

The present study was purposed to find out variables of childhood antisocial behavior. The variables consisted of social cognition competence(Peer perception. acquaintance perception, frustration situation perception). academic competence(Visual integration function. written expression function, grammar closure function). The subject in this study were 32 nine year old-fourteen year old antisocial behavior boys and 32 third grade in elementary school-second grade in middle school normal boys and girls. The results of this study were obtained as follows. 1) In peer perception antisocial behavior children perceived peer as more supportive than normals. In acquaintance perception. there was no difference between groups. 2) In frustration situation perception, normal children used intropunitive attack still more than antisocial behavior children and antisocial behavior children perceived frustration situation more sensitive than normals and they were less active in problem solving aspects than normals. 3) In Academic competence, antisocial behavior children have deficits in visual motor integration function, written expression function. grammar closure function.

• Korean Journal of Psychosomatic Medicine
• /
• v.15 no.2
• /
• pp.73-80
• /
• 2007

Anumber of prior studies have reported eye movement dysfunction in patients with dementia. The eye movement test which is non-invasive can evaluate the local brain function quantitatively. Therefore, it can be a useful method for characterizing regional brain abnormalities of patients with dementia. The aim of this paper is to review the literatures on eye movement abnormalities in dementia patients. Saccade system dysfunctions in Alzheimer disease include increased latency, reduced accuracy, and increased antisaccade error rates. Patients with frontotemporal dementia showed impaired reflexive saccade inhibition and increased latency and errors of antisaccade task. And delayed initiation of voluntary saccades, slow saccades, and increased errors and latency on antisaccade task were found in Huntington's disease. Patients with Parkinson’s disease dementia and dementia with Lewy bodies have characteristics of impaired in both reflexive saccade execution and complex saccade performance. However, there were few reports of abnormal eye movements in Creutzfeldt-Jakob disease; they could be found at the later stages after symptoms of dementia came to be evident, and secondary to cerebellar and vestibular involvement. Slowing of saccades and hypometric saccades might precede the supranuclear limitation of vertical gaze in PSP. Dysfunction of voluntary eyelid movements was a characteristic finding of PSP as well. In conclusion, patients with dementia can show various abnormal eye movements and they are related with cortial and subcortical brain dysfunctions. The research on localization of brain relevant to each symptom can promise more clinical implications of eye movement of dementia.

• Geophysics and Geophysical Exploration
• /
• v.15 no.3
• /
• pp.121-128
• /
• 2012

Absorbing boundary conditions are used to mitigate undesired reflections that can arise at the model's truncation boundaries. We apply a complex frequency shifted perfectly matched layer (CFS-PML) to elastic wave modeling in the frequency domain. Modeling results show that the performance of our implementation is superior to other absorbing boundaries. We consider the coefficients of CFS-PML to be optimal when the kinetic energy becomes to the minimum, and propose the modified CFS-PML that has the CFS-PML coefficient ${\alpha}_{max}$ defined as a function of frequency. Results with CFS-PML and modified CFS-PML are significantly improved compared with those of the classical PML technique suffering from large spurious reflections at grazing incidence.

• Journal of the Korean Geophysical Society
• /
• v.2 no.4
• /
• pp.241-250
• /
• 1999

Reflection coefficients of the seafloor have been calculated from the amplitude ratio of secondary to primary water bottom reflection in seismic data obtained from Bransfield Strait, Antarctic Peninsula. Test processing for the coefficients shows that moving average is effective to reduce severe fluctuation of the coefficient measured at each point. Relationship between the coefficients and the properties of water bottom is analyzed to illuminate geological environment. In the central Bransfield Basin, the magnitude of reflection coefficients decreases as it is distant from the sedimentary sources. Reflection coefficients range from 0.12 to 0.2 near the continental slope of the basin, and from 0.1 to 0.12 in the basin floor. In the western Bransfield basin, reflection coefficients between 0.2 to 0.3 are obtained from the area eroded by glacial movement. On the volcanic structures near Deception Island, the coefficients show relatively high values more than 0.2. Paleo-geological structures uplifted by tectonic movement and outcropped by glacial erosion have relatively high coefficients.

• The Journal of Korean Physical Therapy
• /
• v.11 no.2
• /
• pp.51-59
• /
• 1999

Standing up from a supine and prone position is very important for physical independence. All kinds of patients have a bed rest or lying on floor without special care. Even though the patient had complete from illness. He must train the functional activities before discharge. There are many method for the functional activity training. Likewise, sing of reflex, voluntary movement for muscle strength increasing, but clinically ideal method is approaching with motor developmental stage. Supine and prone progression of proprioceptive neuromuscular facilitation have a ideal reason. That is reflex integratation, development of muscle tone, develop of motor control, dynamic and static, motor behavior and cognition.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
• /
• 2002.08a
• /
• pp.62-65
• /
• 2002

파랑은 주로 먼바다에서 바람에 의해 생성되어 육지로 전파해오면서 천수, 굴절, 회절, 반사, 부서 짐 등의 여러 가지 변형의 과정을 거친다. 이러한 파랑의 변형을 예측하는 한 방법은 비압축성 유체와 비회전류의 연속방정식인 Laplace 방정식을 지배 방정식으로 하고 해수면에서의 운동학적 경계조건과 동역학적 경계 조건, 그리고 바닥에서의 운동학적 경계조건을 적용하여 해를 구한다. (중략)