• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1996년도 추계학술대회
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• pp.217-220
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• 1996

In this paper, we compare three mehods to obtain PSD of HRV - FFT, AR modeling, and residual integration. Using these methods we speculate the balances of the LP and HF powers of HRV at $0^{\circ}$, $45^{\circ}$, $90^{\circ}$ tilt levels of head-up tilt table for young and healthy 24 men. R peaks are located at the highest point of QRS complex detected from modified spacial velocity algorithm. In general FFT is the most fast way to obtain PSD but PSD from FFT has too many peaks and valleies. AR PSD can show frequency of ANS activity effectively but LF component of PSD is often invisible due to interference of VLF power. The residual integration method that decomposes the AR PSD is very efficient way to extract LF component. Applying the above three methods to HRV we can visualize the trend of PSD variations along tilt levels.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 G
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• pp.2370-2372
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• 1998

Recently we have developed an active stereo head-eye system with vergence, name it KIST HECter(Head-Eye System with Colored Stero Vision), based on the analysis of human's neck and eye motion at visual behavior. Our HECter is a five degree-of-freedom system composed of pan and tilt motion in neck part and independent vergence motion of binocular cameras and commonly shared elevation axis in eye part. And stereo vision Provides two color image, which are processed by powerful each TMS32080 vision board. The shape and size are designed to be almost same as human face. The ability to vergence has significant importance and gives many beneficial merits. On its mechanical implementation we adapt a non-parallelogram 4-bar linkage mechanism since it provides high accuracy in transfering motion and enables compact and flexible design.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 학술대회 논문집 정보 및 제어부문
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• pp.89-90
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• 2008

본 논문은 네트워크를 통해서 이동로봇을 원격제어하기 위해 필요한 비전 시스템에서 HMD(Head Mounted Display)의 방향각 측정 알고리즘에 관한 연구이다. 우선 이 이동로봇 원격제어 시스템은 AP와 무선랜을 이용하여 독립 무선 네트워크를 구축하였고 이동로봇의 주변 환경을 레이저 센서와 스테레오 카메라를 이용하여 사용자에게 정보를 전송한다. 스테레오 카메라를 통해 전송된 영상 정보는 HMD를 통하여 볼 수 있다. 실시간으로 영상 카메라에 의해 측정 된 HMD의 회전 각도는 pen-tilt에 전송되어 HMD가 회전한 만큼 pen-tilt도 회전하여 이동로봇의 주변 환경 영상정보를 얻을 수 있는 알고리즘을 제안하였다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제13권1호
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• pp.50-58
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• 2013

Estimating a driver's head pose is an important task in driver-assistance systems because it can provide information about where a driver is looking, thereby giving useful cues about the status of the driver (i.e., paying proper attention, fatigued, etc.). This study proposes a system for estimating the head pose using monocular images, which includes a novel use of backprojection. The system can use a single image to estimate a driver's head pose at a particular time stamp, or an image sequence to support the analysis of a driver's status. Using our proposed system, we compared two previous pose estimation approaches. We introduced an approach for providing ground-truth reference data using a mannequin model. Our experimental results demonstrate that the proposed system provides relatively accurate estimations of the yaw, tilt, and roll angle. The results also show that one of the pose estimation approaches (perspective-n-point, PnP) provided a consistently better estimate compared to the other (pose from orthography and scaling with iterations, POSIT) using our proposed system.

• 수산해양기술연구
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• 제53권4호
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• pp.396-403
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• 2017

We measured the target strength according to the swimming tilt angle and size change for Pacific herring at the frequency of 70 kHz as the basic database in order to estimate its abundance as well as density in the survey area using the hydroacoustical method. The number of the sample used in this study was 14 individuals, and its size distribution by fork length ranged between 20.3 and 29.8 cm and wet weight was measured between 187.6 and 269.9 g. The variation of TS according to the swimming angle ($-30{\sim}30^{\circ}$) was measured between 10.3 and 18.8 dB in frequency range, the highest value was measured at head-down of Pacific herring in the tilt angle range between 5 and 9 deg. of its swimbladder. The relationship between TS-FL of herring was the same as $TS=20log_{10}$ (FL) - 66.79 when its swimming tilt angle in the daytime ($3.8{\pm}6.0^{\circ}$) and nighttime ($-3.2{\pm}13.6^{\circ}$), respectively.

• The Korean Journal of Physiology
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• 제5권2호
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• pp.71-78
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• 1971

Anesthetized dogs were tilted from horizontal to the upright and head down position. Tilting to the upright position was followed by an increase in heart rate. In the head down position a decreased heart rate was obtained. The arterial blood pressure was decreased in the upright position and was decreased markedly in the head down position. The central venous pressure was decreased in the upright position and was markedly decreased down to the negative pressure in the head down position. The respiratory rate was slightly increased in the upright position comparing to that in the horizontal position. No remarkable changes were noted in the head down position. From the above results the following factors were discussed The decreased arterial blood pressure during the upright position was supposed to be the secondary effect from the diminished venous return that was suggested by the decreased central venous pressure. The decreased arterial blood pressure in the head down position was also supposed as the above reason as the diminished central venous pressure during the tilt. In addition the cardioinhibitory effects originated from the baroreceptors might have been operated during head down tilting. In the heart rate there was slight tachycardia in the upright position this was assumed as the abolished cardioinhibitory impulses from the baroreceptor in the upright position. On the contrary, despite of the decrease of arterial blood pressure in the head down position as well as in the upright, the bradycardia have been appeared. This was suggestive of cardioinhibitory impulses from the baroreceptors which was stretched during head down tilting. From the above findings there is a possibility of continous cardioinhibitory responses during head down tilting for this kind of the short period of 10 minutes which was chosed in this study.

• Annals of Clinical Neurophysiology
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• 제12권2호
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• pp.61-65
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• 2010

Background: Orthostatic hypotension (OH) refers to a fall in systolic blood pressure (BP) of 20 mmHg or more, or in diastolic BP of 10 mm Hg or more within 3 minutes of standing up. The head-up tilt test (HUT) is the most useful, but potentially invasive test for the diagnosis of OH. The purpose of this study was to identify the usefulness of spontaneous baroreflex sensitivity (sBRS). Methods: Ninety one patients with orthostatic intolerance, in whom the HUT data were available, were included in the study. Patients were classified into HUT-positive (group I) and HUT-negative (group II) group. Twenty five healthy volunteers served as normal controls, and were designated as group III. In all subjects, beat-to-beat BP and heart rate were recorded using BeatScope 1.1a. We collected the 50 sBRS data in each patient in a supine position. The average value of one to ten of 50 sBRS data was defined as sBRS10, one to twenty as sBRS20, one to thirty as sBRS 30, one to forty as sBRS 40, and one to fifty as sBRS 50. Differences in sBRS10 and sBRS50 levels were statistically analyzed and compared between groups I, II, and III. Results: No significant difference in the sBRS50 level was found between Groups II and III. sBRS50 was significantly lower in Group I than in Groups II and III (p<0.05), and the same pattern of differences was observed for sBRS40, sBRS30, sBRS20, and sBRS10. Conclusions: Patients with OH showed significantly lower sBRS levels than HUT-negative patients or normal controls. Our study implies that a supine-position sBRS would provide additional diagnostic information for OH.

• 한국임상수의학회지
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• 제23권3호
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• pp.340-343
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• 2006

10년령의 암컷 비글 견이 우측으로의 사경과 중등도의 보행실조가 급성으로 발병하여 내원하였다. 12일 전에 임상증상이 나타났으며, 이는 내원 일까지 점진적으로 호전되고 있는 상태였다. 환견은 활발하고 의식이 명료하며 외부자극에 잘 반응하였다. 신경 검사 상에서 약간의 우측으로의 사경과 보행실조가 관찰되었고 따라서 전정계 질환을 의심할 수 있었다. 임상증상, 자기공명영상, 그리고 뇌척수액 검사를 통해서 중추성 전정계 질병을 감별하였다. 검이경 검사를 통해서 고막의 존재와 정상 형태를 확인하였다. 방사선 및 자기공명영상 검사상에서 고실불룩과 측두골의 암석부분에서 이상소견을 발견할 수 없었다. 갑상선 자극 호르몬 자극 시험을 통해서 갑상선 기능 저하증을 감별하였다. 임상증상은 퇴원 2주 후 완전히 사라졌다. 따라서 임상증상, 전정계 기능이상을 유발하는 다른 원인들의 감별, 그리고 시간에 따른 증상의 완화를 통해서 특발성 전정계 질병으로 진단 할 수 있었다.

• 한국방사선학회논문지
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• 제16권7호
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• pp.857-862
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• 2022

본 연구의 목적은 토모다이렉트를 이용한 토모테라피 방사선치료에서 두상 각도(head tilting)에 따라 3차원 입체조형 전뇌 방사선치료 계획을 평가하고 자 하였다. 총 다섯 가지 두상 각도(-20°, -10°, 0°, +10°, +20°)를 비교 평가하였다. 두상 각도에 따라 표적에 대한 선량균질지수(homogeneity index, HI)와 처방선량지수(conformity index, CI)를 계산하였고, 정상 장기인 수정체, 안구, 귀밑샘에 대한 최대선량과 평균 선량을 구하였다. 선량균질지수와 처방선량지수는 두상 각도가 +10°와 +20°에서 수치 1에 가까웠다. 두상 각도 +10°에서 수정체와 안구의 선량은 기준 두상각도(0°)에 비해 각각 약 74%와 30% 감소하였다. 턱을 올린 상태의 +10°의 두상 각도는 표적에 대한 선량균일지수와 처방선량지수가 적합하며 렌즈와 안구의 선량을 줄일 수 있는 각도로써 권장한다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2009년도 정보 및 제어 심포지움 논문집
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• pp.360-362
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• 2009

In this paper, we studied for the real-time azimuthal measurement of HMD(Head Mounted Display) using the feature points detection to control the tele-operated vision system on the mobile robot. To give the sense of presence to the tele-operator, we used a HMD to display the remote scene, measured the rotation angle of the HMD on a real time basis, and transmitted the measured rotation angles to the mobile robot controller to synchronize the pan-tilt angles of remote camera with the HMD. In this paper, we suggest an algorithm for the real-time estimation of the HMD rotation angles using feature points extraction from pc-camera image.