• Imaging Science in Dentistry
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• 제45권2호
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• pp.73-80
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• 2015

Purpose: This study evaluated the effect of various head orientations during cone-beam computed tomography (CBCT) image acquisition on linear measurements of potential implant sites. Materials and Methods: Six dry human skulls with a total of 28 implant sites were evaluated for seven different head orientations. The scans were acquired using a Hitachi CB-MercuRay CBCT machine. The scanned volumes were reconstructed. Horizontal and vertical measurements were made and were compared to measurements made after simulating the head position to corrected head angulations. Data was analyzed using a two-way ANOVA test. Results: Statistical analysis revealed a significant interaction between the mean errors in vertical measurements with a marked difference observed at the extension head position (P<0.05). Statistical analysis failed to yield any significant interaction between the mean errors in horizontal measurements at various head positions. Conclusion: Head orientation could significantly affect the vertical measurements in CBCT scans. The main head position influencing the measurements is extension.

• 한국의류학회지
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• 제29권8호
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• pp.1079-1091
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• 2005

The purpose of this study was to point out the unification of the size of swimming headgear by measuring detailed measurement of head ferm and systematizes the head form. A total of 300 male and female Korean adults aged from 18 years old to 35 years old were measured through the direct measurement method. This study attempted to identify the head form of male and female adults using measurement data and the head form was classified through factor analysis and cluster analysis. (1) Based on the fact that this study especially focuses on the size of swimming headgear, factor analysis was performed far both direct measurements with hair and without hair. For the measurements with hair, seven factors were extracted. They were head thickness factor, head width factor, width of side head factor, height of back head factor, length of front head factor, circumference of front head factor, thickness of front head factor and head height factor. They explained the $70.95\%$ of the measurements. (2) The cluster analysis was executed to classify the somatotype of the korean head form on the basis of similarity. According to the cluster analysis result, the measurements with hair categorized types, 'Woman's long-hair type', 'Small type', 'Long and flat type', 'Large type'. (3) Head circumference B and Left tragion - Vertex - Right tragion circumference which are generally length and width in choosing swimming headgear size were selected as measurement items far size of swimming headgear. Direct measurements and sizes of four swimming headgear with different materials taking into account their elongation rate were also compared.

• 한국지하수토양환경학회지:지하수토양환경
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• 제18권2호
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• pp.45-53
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• 2013

Many cases of strategically designed groundwater remediation have lack of information of hydraulic conductivity or permeability, which can render remediation methods inefficient. Many studies have been carried out to minimize this shortcoming by determining detailed hydraulic information either through direct or indirect measurements. One popular method for hydraulic characterization is the pilot point method (PPM), where the hydraulic property is estimated at a small number of strategically selected points using secondary measurements such as hydraulic head or tracer concentration. This paper adopted a D-optimality based pilot point method (DBM) developed previously for hydraulic head measurements and extended it to include both hydraulic head and tracer measurements. Based on different combinations of trials, our analysis showed that DBM performs well when hydraulic head is used for pilot point selection and both hydraulic head and tracer measurements are used for determining the conductivity values.

• 한국의류학회지
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• 제42권6호
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• pp.988-1001
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• 2018

The head and face are the most complicated structures of the human body. However, unlike apparel products, many of the head and face related products are produced in unisex or one-size-fits-all. Therefore, it is necessary to provide a practical analysis that reflects these size structures. This study analyzed head and face measurements of men, women, and both men and women; its purpose lying in clarifying the differences and commonalities between the measurements of men and women and discovering the possibility of integrating analysis on measurements of men and women. 3D face and head measurement data of men and women from 20 to 29 years-old from Size Korea's 6th human body size data were analyzed for this study. The mutual 9 factors were extracted as the results of the three factor analyses (both men and women) separately and men and women integrated. However in the cluster analysis based on the 9 factors, men and women showed mutual characteristics and different landscape in group types and distribution. The commonalities and differences between men and women observed in this study should be applied to the sizes of head and face products.

• 치과방사선
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• 제12권1호
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• pp.49-56
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• 1982

The purpose of this study was to observe the anatomic variation of condylar head and the positional relationship between condylar head and other anatomic structures of head by means of cephalometry using the submentovertex cephalogram from each person in centric occlusion for producing a good quality of temporomandibular joint radiograph. The 100 submentovertex cephalograms of 100 Korean adults consisted of 50 females ranged from 20 to 24 years age and 50 males ranged from 22 to 30 years age, were studied and analyzed statistically. The results were as follows; 1. The mean of the horizontal angulation of condylar head to the transmeatal line (EE-LA) was 18.5° (S.D. 7.9°), and all measurements that indicate the horizontal angulation of condylar head showed considerable differences among individuals. 2. In the comparison of male vs. female in the measurements, statistically significant differences were found in the majority of measurement items, and with exception of R-LA and LA-LA, the rest of these measurements were larger in male than in female. 3. In the comparison of left vs. right in the measurements, statistically significant differences were found in the majority of measurement items, and with exception of PC-CC, the rest of these measurements were larger in right than in left. As above, because the majority of measurements that involve the horizontal angulation of condylar head varied among individuals, between male and female, and between left and right, the condition of various temporomandibular joint radiography should be determined by means of cephalometry using the submentovertex cephalogram for producing the accurate radiographic image of temporomandibular joint.

• 한국의류학회지
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• 제32권9호
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• pp.1397-1406
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• 2008

This research was to develop Taekwondo trunk protector(Hogu) and head protector's sizing systems corresponding the regulations by World Taekwondo Association. These sizing systems were established using 2003-2004 Size Korea anthropometric data. The result can be summarized as follows: According to the analysis of correlation, most measurements had high relationship with weight for Hogu and head girth for head protector. Six sizes(47, 54, 59, 64, 70, 76) for Hogu and 4 sizes(52, 54, 56, 60) for head protector were suggested in this study. Hogu sizes indicate body weights and head protector sizes express head girth measurements. By the comparison between current Hogu sizes and new sizes, the smaller sizes of new Hogu were bigger than current sizes in bust girth, back fastening length, shoulder length. On the other hand, the bigger sizes of new Hogu were larger than current sizes in bust girth, back fastening length, shoulder length. In addition, new Hogu's lengths were shorter than current Hogu in all sizes. The lengths of Neck to collar bone in new Hogu sizes were longer than current Hogu. In case of the head protector, there were no measurements besides outer circumference of helmet in recognized specifications of WTF. Therefore some referable measurements such as head girth, head length, bitragion arc, sagital arc were suggested in new size specification. When helmet sizes were suggested, the thickness of the NBR foam also were considered.

• 대한치과교정학회지
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• 제33권2호
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• pp.73-84
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• 2003

본 연구는 정모두부방사선사진 촬영시 수직적 두부회전이 방사선사진상의 계측치들에 어느 정도의 투사오차를 야기 시키는지 알아보고자 시행되었다. 임상검사를 통하여 두드러진 전후방 골격이상이나 뚜렷한 안면비 대칭을 보이지 않는 성인 25명을 대상으로 natural head position상태를 기준위치$(0^{\circ})$로 정하고 이 위치에 대해 양쪽 ear rod를 연결한 수평축을 중심으로 두부를 상, 하방으로 $5^{\circ},\;10^{\circ}$씩 회전시킨 상태에서 정모두부방사선사진을 각각 촬영하여 투사도를 작성한 다음 7개의 고경항목, 5개의 폭경항목, 6개의 각도항목을 계측하였다. 각 회전각도에서의 계측치를 비교 분석하여 다음과 같은 결과를 얻었다. 1. 고경계측항목의 투사오차가 폭경이나 각도계측항목에 비해 전반적으로 큰 양상을 나타냈다. 2. 고경계측항목 중 회전축으로부터 먼 계측점간의 거리를 나타내는 항목일수록 투사오차가 컸다. 3. 폭경 계측항목 중 비강폭경, 상악폭경, 상악 제1대구치간 폭경은 각 회전각도 간에 통계적 유의차가 없었으나 하악폭 경과 하악 제1대구치간 폭경은 통지적으로 유의차가 있었다. 4. 각도계측항목 중 menton의 편위정도를 나타내는 각도는 각 회전각도 간에 통계적 유의차가 없었으나 crista galli와 maxillare를 연결한 선이나 crista galli와 antegonion을 연결한 선과 수평기준선이 이루는 각도는 통계적으로 유의차가 있었다. 이상의 결과는 수직적 두부회전에 의해 정모두부방사선사진상에 투사오차가 발생하므로 유용한 정모두부방사선사진을 얻기 위해서는 촬영시마다 동일한 두부위치를 유지하기 위한 노력이 필요함을 시사하였다.

• Safety and Health at Work
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• 제15권1호
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• pp.42-52
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• 2024

Background: The lack of headforms that accurately reflect the head characteristics of Koreans and the demographic composition of the Korean population can lead to inadequate FFR testing and reduced effectiveness of FFRs. Method: Direct measurements of 5,110 individuals and 3D measurements of 2,044 individuals, aged between 9 and 69 years, were sampled from the data pool of Size Korea surveys based on the age and gender ratios of the Korean resident demographics. Seven head dimensions were selected based on the ISO 16976-2, availability of Size Korea measurements, and their relevance to the fit performance of FFRs. A principal component analysis (PCA) was performed using the direct measurements to extract the main factors explaining the head characteristics and then the main factors were standardized and remapped to 3D measurements, creating five size categories representing Korean head shapes. Lastly, representative 3D headforms were constructed by averaging five head shapes for each size category. Results: The study identified two main factors explaining Korean head characteristics by the PCA procedure specified in ISO 16976-2 and developed five representative headforms reflecting the anthropometric features of Korean heads: medium, small, large, short & wide, and long & narrow. Conclusion: This study developed representative headforms tailored to the Korean population for conducting total inward leakage (TIL) tests on filtering facepiece respirators (FFRs). The representative headforms can be used for TIL testing by employing robotic headforms to enhance the performance of FFRs for the Korean target population.

• 복식
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• 제37권
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• pp.181-190
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• 1998

The purpose of this study was to provide basic information for women's women's head type for mil-inary. The subjects were 141 college women aged from 19∼23. Data were collected from the real anthropometric measurements and 4 index. Correlation coefficientss, factor analysis, cluster analysis and analysis of variance in SAS package. The results were as follows : 4 factors were extracted from 20 anthrometric measurements and in index data, which explain 60.0% of variance. The subjectss were classified into 4 clusters by 11 measurement and 4 index data. Each charicteristics of cluster by the measurements was flat, big, thick, small types in women's head. Each charicteristics of cluster by the index data was mostly flat in head thickness and wide, midium, narrow, very wide type in face.

• 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.