• Tuberculosis and Respiratory Diseases
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• v.45 no.2
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• pp.404-415
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• 1998

Background: Sleep apnea syndrome, which occurs in 1~4 % of the adult population, frequently has different cardiovascular complications such as hypertension, ischemic heart disease, cardiac arrythmia as well as sleep-wake disorder such as excessive daytime hypersomnolence or insomnia. Mortality and vascular morbidity are reported to be significantly higher in sleep apnea syndrome patients than in normal population. According to the recent studies, autonomic dysfunction as well as hypoxemia, hypercapneic acidosis, and increased respiratory effort, may playa role in the high prevalence of cardiovascular complications in patients with sleep apnea syndrome. However the cause and mechanism of autonomic neuropathy in patients with sleep apnea syndrome are not well understood. We studied the existence of autonomic neuropathy in patients with sleep apnea syndrome and factors which influence the pathogenesis of autonomic neuropathy. Method: We used the cardiovascular autonomic neuropathy(CAN) test as a method for evaluation of autonomic neuropathy. The subjects of this study were 20 patients who diagnosed sleep apnea syndrome by polysomnography and 15 persons who were normal by polysomnography. Results: Body mass index and resting systolic blood pressure were higher in sleep apnea group than control group. Apnea index(Al), respiratory disturbance index(RDI) and snoring time percentage were significantly higher in sleep apnea group compared with control group. But there were no significant differences in saturation of oxygen and sleep efficiency in two groups. In the cardiac autonomic neuropathy test, the valsalva ratio was significantly low in sleep apnea group compared with control group but other tests had no differences between two groups. The CAN scores and corrected QT(QTc) interval were calculated significantly higher in sleep apnea group, but there were no significant correlations between CAN scores and QTc interval. There were no significant data of polysomnography to correlate to the CAN score. It meant that the autonomic neuropathy in patients with sleep apnea was affected by other multiple factors. Conclusion: The cardiovascular autonomic neuropathy test was a useful method for the evaluation of autonomic neuropathy in patients with sleep apnea syndrome and abnormalities of cardiovascular autonomic neuropathy were observed in patients with sleep apnea syndrome. However, we failed to define the factors that influence the pathogenesis of autonomic neuropathy of sleep apnea syndrome. This study warrants futher investigations in order to define the pathogenesis of autonomic neuropathy in patients with sleep apnea syndrome.

• Proceedings of the KSLP Conference
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• 1996.11a
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• pp.94-94
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• 1996

미주신경의 마디신경절내에 존재하는 신경세포는 경부, 흉강 및 복강의 감각신경을 지배하는 것으로 알려져 있으며 이와 관련된 SP, CGRP 등의 신경펩디드의 분포에 관하여 많은 보고가 이루어졌다. Vasoactive Intestinal Peptide(VIP)는 혈관, 평활근, 분비선 주위에 분포하는 부교감신경세포의 전달물질로서 후두의 자율신경계의 조절에 중요한 역할을 하고 있다 이러한 VIP지배신경의 기원에 관해서는 미주신경이나 후두신경, 그리고 일부 후두 구조내에 존재하는 부신경절(Paraganglia)에서 기원한 후 신경절 부교감신경으로 알려져 있는데, 즉 미주신경의 마디신경절은 단지 감각신경의 기원이 되는 신경세포 집합체로 마디신경절과 자율신경계의 상관관계에 대한 연구는 극히 드문 실정이다. 그러나 일부 보고에서 성문하부의 점막상피에서 SP나 CGRP외에도 VIP 양성세포가 발견됨으로써 일반적으로 자율신경계 세포로 알려진 VIP 양성세포의 기원과 기능은 더 규명되어야 할 부분의 하나로 사료된다 금번 저자는 고양이의 마디신경절에 대하여 면역 조직화학적 방법을 통한 VIP양성 세포의 출현여부를 관찰함으로써 마디신경절과 자율신경계와의 상관관계를 알아보고자 하였다.

• Clinical and Experimental Pediatrics
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• v.46 no.6
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• pp.585-590
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• 2003

Purpose : This study is designed to determine the prevalence of cardiovascular autonomic neuropathy and its relationship to risk factors in adolescents with diabetes mellitus(DM). Methods : Ninety-two diabetic patients(80 with type 1 DM and 12 with type 2 DM), ranging from eight to 26 years of age, were studied for cardiovascular autonomic function, and the relationship to age, duration of diabetes, glycated hemoglobin(HbA1c), urinary albumin excretion, and the presence of diabetic retinopathy and abnormal nerve conduction velocities(NCV) were analysed. Autonomic function was assessed by measuring heart rate variation during valsalva manoeuvre, deep breathing and standing from a lying position(30 : 15 ratio), and postural hypotension. Results : Among patients with type 1 DM, 22.5% had early, 8.7% had definite, and 1.3% had severe autonomic dysfunction, and among patients with type 2 DM, 16.7% had early, 8.3% had definite, and 8.3% had severe autonomic dysfunction. On logistic regression analysis including both type 1 and type 2 diabetic patients, the age of the patient(OR=1.133(1.003-1.279), P<0.05) and duration of diabetes(OR=1.148(1.009-1.307), P<0.05) significantly predicted cardiovascular autonomic dysfunction while HbA1c, blood pressure, urinary albumin excretion, and presence of diabetic retinopathy and abnormal NCV did not. The valsalva ratio was borderline or abnormal in 31.5% of patients, the heart rate variation on deep breathing in 41.3%, the 30 : 15 ratio in 14.1%, and postural hypotension in 9.8% of patients. The valsalva ratio and the heart rate variation on deep breathing significantly predicted cardiovascular autonomic dysfunction, but the 30 : 15 ratio and postural hypotension did not. Conclusion : Cardiovascular autonomic dysfunction was found in 32.6% of diabetic patients and 10.8 % of patients had definite or severe involvement. The risk of cardiovascular autonomic dysfunction increased with the patient's age and the duration of DM. This study suggests that the valsalva ratio and the heart rate variation on deep breathing are the most useful tests in evaluating the cardiovascular autonomic function in children and adolescents with DM.

• 전기의세계
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• v.46 no.3
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• pp.20-25
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• 1997

자율주행시스템은 복잡한 환경에서 효과적인 주행을 위해서 센서를 통해 주변의 정보를 수집하고 주변환경에 적절한 동작을 취해야 한다. 이러한 자율주행시스템에 지능적인 방법을 통하여 새롭게 제안한 방법을 서술하였다. 퍼지 논리를 이용하여 운전자와 같이 차량이 차선을 따라 주행하기 위한 퍼지 논리 제어기(FLC)가 설계되었다. 함축적인 차량모델을 기반으로 설계한 퍼지 논리 제어기가 복잡하고 정확한 차량모델을 기반으로 설계된 PID나 FSLQ 제어기와 동등한 성능을 발휘하였다. 인간의 운전방법을 학습할 수 있는 신경회로망을 이용하여 자율주행시스템에 적용하였다. 퍼지 신경회로망은 인간의 제어특성을 반영하도록 설계되었으며 자동으로 생성된 제어기는 퍼지 논리 제어나 신경회로망의 기법보다 우수한 성능을 발휘하였다. 퍼지 논리, 신경회로망, 유전자 알고리즘 등의 인간의 지능 모델에 기초를 둔 방법을 자율주행차량의 제어에 도입하므로써 기존의 자율주행시스템의 문제점을 극복하는데 주요한 역할을 하였다. 앞으로 퍼지 논리, 신경회로망, 유전자 알고리즘은 각각의 강점을 융합하거나, 고전적인 제어 알고리즘과 결합하므로써 더욱 우수한 성능을 발휘할 것으로 예상된다.

• Tuberculosis and Respiratory Diseases
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• v.46 no.3
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• pp.317-326
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• 1999

Background: Neural control of airway function is through parasympathetic, sympathetic and non-adrenergic, non-cholinergic mechanisms. The autonomic nervous system controls the airway smooth muscle tone, mucociliary system, permeability and blood flow in the bronchial circulation and release of mediators from the mast cells and other inflammatory cells. The cardiovascular and respiratory autonomic efferent fibers have a common central origin, so altered cardiovascular autonomic reflexes could reflect the altered respiratory autonomic status. Therefore, we performed this study to assess the autonomic abnormality and determine the correlating factors of severity of autonomic neuropathy in patients with chronic obstructive pulmonary disease(COPD) using easily reproducible cardiovascular autonomic reflex function test. Method: The study included 20 patients with COPD and 20 healthy persons obtained on Health Promotion Center in Yeungnam university hospital. All the patients had history and clinical features of COPD as defined by the American Thoracic Society. Any patients with myocardial ischemia, cardiac arrythmia, hypertension, central or peripheral nervous system disease, diabetes mellitus, or any other diseases known to produce autonomic neuropathy, has excluded. The autonomic nervous system function tests included three tests evaluating the parasympathetic system and two tests evaluating the sympathetic system. And also all subjects were subjected to pulmonary function test and arterial blood gas analysis. Results: Autonomic dysfunction was more commonly associated with patients with COPD than healthy person The parasympathetic dysfunction was frequent in patient with COPD, but sympathetic dysfunction seemed preserved. The severity of parasympathetic dysfunction in patients with COPD was correlated with the degree of duration of disease, smoking, reductions in the value of $FEV_1$ and FVC, and arterial hypoxemia but no such correlation existed for age, type of COPD, $FEV_1$/FVC, or $PaCO_s$. Conclusion: There is high frequency of parasympathetic dysfunction associated with COPD and the parasympathetic abnormality in COPD is increased in proportion to severity of airway disease. In COPD, parasympathetic dysfunction probably does not the cause of disease, but it may be an effect of disease progression.

• Progress in Medical Physics
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• v.6 no.2
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• pp.103-109
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• 1995

Power spectral analysis of spontaneous heart rate fluctuations were assessed by use of autooic blocking agents and changes in posture. The total power spectral range of interest is divided amongst the various experiments so that each respiratory pattern contributes a spectral ratio of interval to respiration only over a group of frequencies for which the specific respiratory pattern has substantial, and roughly constant, spectral magnitudes. System hardware is consisted ECG preamplifier, respiratory fluctuation detect, interval time generator and IBC 486PC. High frequency fluctuation, at the respiratiory frequency, are decreased by standing and are mediated solely by the parasympathetic system. Power spectral analysis is a powerful nonivsve tool for quantitying autonomic nervous system activity.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1789-1790
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• 2007

이 논문에서 우리는 생체모방 시스템을 구현하기 위해 일반적인 기계 시스템과 인간의 신경 진동자 모델을 결합하였다. 이러한 시스템은 외부환경의 변화에 따른 효과적인 자율 적응 운동 형태를 생성할 수 있다. 인간 및 동물의 주기적 자율 운동을 관장하는 Central Pattern Generator (CPG)는 신경 진동자 네트웍에 의해서 표현가능하고 이는 신경 진동자 모델 내부의 sensory 피드백 신호를 통해, 주기성을 같은 외란에 상호 작용하여 적절한 운동을 생성해 낸다. 따라서 이를 기계 시스템에 결합하면 이러한 시스템은 변화되는 환경이나 잘 알지 못하는 외란에 대하여 자율적으로 적응된 운동을 보일 수 있다. 이를 위해 본 논문은 이러한 신경 진동자 모델과 결합된 realtime 시스템을 구현하고 그 자율 적응 운동의 생성 가능성을 살펴본다.

• KIPS Transactions on Computer and Communication Systems
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• v.12 no.3
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• pp.93-102
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• 2023

Data processing through the cloud causes many problems, such as latency and increased communication costs in the communication process. Therefore, many researchers study edge computing in the IoT, and autonomous driving is a representative application. In indoor self-driving, unlike outdoor, GPS and traffic information cannot be used, so the surrounding environment must be recognized using sensors. An efficient autonomous driving system is required because it is a mobile environment with resource constraints. This paper proposes a machine-learning method using neural networks for autonomous driving in an indoor environment. The neural network model predicts the most appropriate driving command for the current location based on the distance data measured by the LiDAR sensor. We designed six learning models to evaluate according to the number of input data of the proposed neural networks. In addition, we made an autonomous vehicle based on Raspberry Pi for driving and learning and an indoor driving track produced for collecting data and evaluation. Finally, we compared six neural network models in terms of accuracy, response time, and battery consumption, and the effect of the number of input data on performance was confirmed.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2005.11a
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• pp.185-188
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• 2005

본 논문에서 신경망을 이용한 자계기반 자율주행 시스템의 조향 제어기 설계를 제안한다. 자율주행시스템에서 가장 중요한 핵심요소는 자계토로상의 센서의 현재위치를 파악하고 주행하는 것이다. 먼저 자계도로상의 현재위치를 파악하기 위한 방법으로, 첫 번째 자기쌍극자 모델식이 센서에서 측정된 자계와 일치함을 보였다. 두 번째 Peak Mapping법을 이용하여 외란으로 작용하는 지자계 성분을 제거할 수 있음을 입증하였다. 세 번째로 신경망을 이용하여 높이성분($B_{z}$)가 변하더라도 정확한 거리가 계측됨을 확인하였다. 따라서 신경망을 이용하면 소량의 메모리를 사용할 수 있으므로 실제 시스템에서 경제적인 효과를 볼 수 있고, 정확한 거리를 계측하므로 경로를 이탈하지 않고 자율주행이 가능한 시스템을 설계하였다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2019.01a
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• pp.261-262
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• 2019

본 논문에서는 신경망 모델에 키보드를 통한 주행 학습을 이용하여 자율 주행을 할 수 있는 시스템을 개발하였다. 주어진 트랙에서 키보드의 방향키를 통해 전진, 후진 등 5가지의 상태로 RC카를 수동 제어하고, 제어시 카메라를 통해 얻어진 이미지를 저장해, 키 제어 데이터와 이미지 데이터를 학습시켜서 자율 주행을 할 수 있는 시스템을 구현하였다.