• 대한인간공학회지
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• 제19권1호
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• pp.77-90
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• 2000

The aim of this study is to develop and evaluate an efficient camera calibration method for vision-based head tracking. Tracking head movements is important in the design of an eye-controlled human/computer interface. A vision-based head tracking system was proposed to allow the user's head movements in the design of the eye-controlled human/computer interface. We proposed an efficient camera calibration method to track the 3D position and orientation of the user's head accurately. We also evaluated the performance of the proposed method. The experimental error analysis results showed that the proposed method can provide more accurate and stable pose (i.e. position and orientation) of the camera than the conventional direct linear transformation method which has been used in camera calibration. The results of this study can be applied to the tracking head movements related to the eye-controlled human/computer interface and the virtual reality technology.

• The Journal of Korean Physical Therapy
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• 제7권1호
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• pp.33-42
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• 1995

The purposes of this study were 1) to compare weight distribution and ratio of the extremities between normal and hemiplegic children in quadruped position and 2) to compare the effect of ATNR on weight bearing of the extremities between normal and hemiplegic children. The subjects fer the study were 48 children(24 normal, 24 hemiplegic) between the ages 3 to 6. They were teated weight distribution and ratio of the extremities in the neutral position of head and by passive right and left rotation of the head in the quadruped position. The data wert analized by paired t-test. The results were as follows: 1. In the neutral position of head, normal group was not difference on weight distribution and ratio of the extremities and hemiplegic group was more weight bearing on the sound upper extremity than the affected upper extremity(p<.01). 2. When the head rotated to the dominant side or sound side passively, there was not a significant difference between normal and hemiplegic group. 3. When the head rotated to the nondominant side or affected side passively, there was a significant difference between nondominant upper extremity nf normal and affected upper extremity of hemiplegic group(p<.05).

• Journal of Dental Anesthesia and Pain Medicine
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• 제18권1호
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• pp.41-46
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• 2018

Background: The purpose of this prospective randomized single-blind clinical trial was to evaluate the effect of tilting the head on the anesthetic efficacy of inferior alveolar nerve block (IANB) in patients with symptomatic irreversible pulpitis. Methods: Ninety-two patients were divided into two groups: the first group received IANB and the head was tilted in the direction of the block for 15 min, whereas the second group received IANB and the head was tilted to the opposite side. Access cavity preparation was initiated after 15 min. Success was defined as no pain or faint/weak/mild pain during endodontic access preparation and instrumentation. The anesthetic success rates were analyzed by Pearson chi-square test at 5% significance levels. Results: The same side position and opposite side position yielded 41% and 30% anesthetic success rates, respectively; there was no significant difference between the two sides. Conclusions: Relative head position has no effect on the anesthetic success rate of IANB.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2011년도 추계학술대회
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• pp.173-175
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• 2011

본 논문에서는 얼굴의 3차원 위치와 방향을 추적하여 3D 물체를 다각도에서 볼 수 있는 사용자 인터페이스를 제시한다. 구현된 사용자 인터페이스는 사용자가 상하좌우로 얼굴을 움직였을 때, 얼굴의 3차원 위치 좌표를 이용하여 사용자가 움직이는 방향으로 물체를 이동시킨다. 그 뒤 사용자가 상하(pitch)좌우(yaw)로 얼굴을 회전시켰을 때, 얼굴의 Euler angle값을 이용하여 얼굴의 회전각만큼 물체를 회전시켜 물체의 측면을 제공한다. 다양한 위치와 방향에 사용자가 있을 때 물체의 움직임의 정확성과 반응성을 실험한 결과 시각화가 잘 됨을 확인하였다.

• Imaging Science in Dentistry
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• 제39권3호
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• pp.133-147
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• 2009

Purpose : To investigate the reproducibilities and compare the measurements in digital and MDCT-synthesized cephalometric radiograph, and to investigate the effect of head position on the measurement during imaging with MDCT. Materials and Methods : Twenty-two dry skulls (combined with mandible) were used in this study. Conventional digital cephalometric radiograph was taken in standard position, and MDCT was taken in standard position and two rotated position ($10^{\circ}$ left rotation and $10^{\circ}$ right tilting). MDCT data were imported in $OnDemand^{(R)}$ and lateral cephalometric radiograph were synthesized from 3D virtual models. Two types of rotated MDCT data were synthesized with default mode and with corrected mode using both ear rods. For all six images, sixteen angular and eleven linear measurements were made in V-$Ceph^{(R)}$ three times. Reproducibility of measurements was assessed using repeated measures ANOV A and ICC. Linear and angular measurements were compared between digital and five MDCT-synthesized images by Student t-test. Results : All measurements in six types of cephalometric radiograph were not statistically different under ICC examination. Measurements were not different between digital and MDCT-synthesized images (P>.05). Measurements in MDCT-synthesized image in $10^{\circ}$ left rotation or $10^{\circ}$ right tilting position showed possibility of difference from digital image in some measurements, and possibility of improvement via realignment of head position using both ear rods. Conclusion : MDCT-synthesized cephalometric radiograph can substitute conventional cephalometric radiograph. The error on head position during imaging with MDCT have possibility that can produce measurement errors with MDCT-synthesized image, and these position error can be corrected by realignment of the head position using both ear rods.

• 한국의학물리학회지:의학물리
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• 제34권1호
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• pp.10-13
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• 2023

Patients with breast cancer can be positioned with their head turned to the contra lateral side or with their head straight during the radiation therapy treatment set-up. In our hospital, patients with locally advanced breast cancer who were receiving radiation therapy have experienced swallowing difficulty after 2 weeks of irradiation. In this pilot study, the impact of head position on reducing dysphagia occurrence was dosimetrically evaluated. Patients were divided into two groups viz., HT (head turned to the contra lateral side of the breast) and HS (head straight) with 10 members in each. Treatment planning was performed, and the dosimetric parameters such as Dmin, Dmax, Dmean, V₅, V₁₀, V₂₀, V₃₀, V₄₀, and V₅₀ of both groups were extracted from the dose volume histogram (DVH) of esophagus. The target coverage in the supraclavicular fossa (SCF) region was analyzed using D₉₅ and D₉₈; moreover, the dose heterogeneity was assessed with D₂ from the DVHs. The average values of the dose volume parameters were 27.6%, 58.6%, 35.4%, 19%, 13.8%, 14.1%, 11.8%, 8.4%, and 8.1% higher in the HT group compared with those in the HS group. Furthermore, for the SCF, the mean values of D₉₈, D₉₅, and D₂ were 42.4, 47.5, and 54 Gy, respectively, in the HS group and 38.9, 45.35, and 55.5 Gy, respectively, in the HT group. This pilot study attempts to give a solution for the poor quality of life of patients after breast radiotherapy due to dysphagia. The findings confirm that the head position could play a significant role in alleviating esophageal toxicity without compromising tumor control.

• 치과방사선
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• 제22권2호
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• pp.315-327
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• 1992

The purpose of this study was to evaluate the utilization of the orthopantomograph as a diagnostic aid to observe maxillary sinus and adjacent structures. For achieving this goal. the lead plates were attached to the five walls of the maxillary sinus of a human dry skull. The dry skull was placed in fourteen different positions; standard. 20mm forward. 20mm backward. 10 degree upward. 10 degree downward. 20mm lateral. forward & upward, forward & downward. forward & lateral. backward & upward. backward & downward, backward & lateral. upward & lateral. downward & lateral position. The obtained results were as follows: 1. The image of the medial wall was observed very differently according to the head positions. 2. The image of the anterior wall was observed at medial third to half of the maxillary sinus in each head position. 3. the image of the posterior wall was always observed at lateral third of the maxillary sinus in all head positions and more obviously in the downward-lateral position. 4. The image of the superior wall was observed at the inferior third to half of the orbit in each head position. 5. The image of the inferior wall was always observed at the inferior third of maxillary sinus in all head positions and observed more obviously in the standard and downward-lateral positions. 6. The images of the zygomatic process. zygomatic arch and zygomaticotemporal suture were observed very well in the downward-lateral position.

• 치과방사선
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• 제11권1호
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• pp.79-87
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• 1981

The author analysed the interrelation between the morphologic changes of bone Structures and the position of condylar head from the routine radiographs of 134 cases of the temporomandibular joint arthrosis. The frequencies of coincidence between the site of bone defrmity and condylar head positional change were examined. Also, the positional changes of condylar head and the direction of condylar movement in relation to the kind of bone deformities were observed. The results obtained were as follows; 1. In 52.65 per cent of total cases, the site, of positional change of condylar head was coincided with the site of bone deformans. The frequencies of the coincidence between these in the five items among seven items examined were above 53 per cent. From the results, it seems that the positional changes of condylar head were related with the morphological change of bone structure. 2. Eburnation and erosion. revealed frequently positional changes in the opening and closing position of the mouth, although in the early stages of the TMJ arthrosis. 3. In the bone deformans, during opene position of the mough 44.81 per cent of total cases revealed backword movement and 37.74 per cent showed forward movement. In closed position of the mouth, downward movement was revealed in 35.23 per cent of total cases and upward movement 28.41 per ,cent of total cases. 4. In the cases showing eburnation, the frequencies of coincidence between the site of positional change and bone deformans were 58.57 per cent of the total cases. that means it was high in the early stages of the TMJ arthrosis.

• The Korean Journal of Physiology
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• 제12권1_2호
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• pp.35-40
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• 1978

경사대에 의한 수등적체위 변화시 분시 호흡수, 혈액 pH, $PCO_2$ 및 $PO_2$의 변화를 관찰하고 다음과 같은 성적을 얻었다. 체위변화시 호흡수는 기립위에서는 수평대조치에 비해 감소하고 도립위에서는 많은 증가를 보였다. 혈액 pH는 기립위에서 수평대조치에 비해 동맥혈은 0.2%가 증가되었고 정맥혈은 0.3%가 감소하였다. 도립위에서는 수평대조치와 거의 변화가 없는 값을 나타내었다. $PCO_2$는 기립위에서 수평대조치에 비해 동맥혈은 8.3%, 정맥혈은 0.3%가 감소되었고 도립위에서는 동맥혈은 20.1%가 감소되고 이것은 통계적으로 의의있는 변화였다. 정맥혈은 7%가 감소되었다. $PO_2$는 기립위에서 동맥혈은 2%가 증가, 정맥혈은 21.7%가 감소되었으며 이것은 통계적으로 의의있는 변화였다. 도립위에서는 동맥혈은 11.4%가 증가되고 정맥혈은 14.1%가 감소되었다. 도립위에서 동맥혈의 $PO_2$가 증가 되는 원인은 도립중의 과도호흡하에 의한 것이라 사료되며 정맥혈의 $PO_2$의 감소는 도립중의 근육수축에 연유하는 산소소비량의 증가가 그 원인이라고 사료된다. 또 도립위에서 $PO_2$가 감소하고 수소ion의 감소가 예상됨에도 불구하고 pH가 증가하지 않는것은 산소소비가 증가되고 정맥혈의 $PO_2$가 감소되는 것으로 봐서 염기성해당으로 젖산이 증가된것이 아닌가 생각된다.

• 대한치과교정학회지
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• 제24권2호
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• pp.405-417
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• 1994

The purpose of this study was to investigate proportional characteristics of soft tissue profile in Korean young adults. The sample consisted of 50 young adults(25 males and 25 females) who had pleasing profile and normal occlusion. Soft tissue proportional analysis was performed on lateral cephalograms taken in natural head position. The results were as follows : 1. Mean and standard deviation of proportional analysis were obtained. 2. Horizontal and vertical dimensions were larger in male. But facial proportion had no sexual difference except upper/lower face height (p<0.05). Upper/lower face height was larger in female than in male. 3. Vertical dimensions, except SN-ST, had high correlation with horizontal dimensions. 4. Head positioning error of natural head position was smaller than inter -individual variability of SN line.