• Journal of the Korean Society for Precision Engineering
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• v.23 no.8 s.185
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• pp.72-79
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• 2006

We measured grating pitch standards using optical diffractometry and analyzed measurement uncertainty. Grating pitch standards have been used widely as a magnification standard for a scanning electron microscope (SEM) and a scanning probe microscope (SPM). Thus, to establish the meter-traceability in nano-metrology using SPM and SEM, it is important to certify grating pitch standards accurately. The optical diffractometer consists of two laser sources, argon ion laser (488 nm) and He-Cd laser (325 nm), optics to make an incident beam, a precision rotary table and a quadrant photo-diode to detect the position of diffraction beam. The precision rotary table incorporates a calibrated angle encoder, enabling the precise and accurate measurement of diffraction angle. Applying the measured diffraction angle to the grating equation, the mean pitch of grating specimen can be obtained very accurately. The pitch and orthogonality of two-dimensional grating pitch standards were measured, and the measurement uncertainty was analyzed according to the Guide to the Expression of Uncertainty in Measurement. The expanded uncertainties (k = 2) in pitch measurement were less than 0.015 nm and 0.03 nm for the specimen with the nominal pitch of 300 nm and 1000 nm. In the case of orthogonality measurement, the expanded uncertainties were less than $0.006^{\circ}$. In the pitch measurement, the main uncertainty source was the variation of measured pitch values according to the diffraction order. The measurement results show that the optical diffractometry can be used as an effective calibration tool for grating pitch standards.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.35 no.3
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• pp.43-52
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• 2003

The new principle to measure a sizing degree by a contact angle was developed using an automatic determination of the 3-end point coordinates of the water droplet on a sheet, which could diminish the operator's bias during measurement. A constant amount of water was first placed on a sample sheet by a water dispenser, and then an image of the liquid droplet was captured by a digital camera and then transmitted to a computer. The program measuring for contact angle extracted a liquid contour by Gaussian function combined with a 8-direction chain code. The Euclidean equation was applied to the binary image of the liquid contour in order to measure the diameter of the contour. Finally, the contact angle of the liquid was calculated by using the diameter and the top coordinates. In addition, a surface free energy of the sample sheet and an elapsed time taken up to the complete absorption into the sheet were simultaneously measured with the contact angle.

• Journal of Welding and Joining
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• v.17 no.6
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• pp.53-61
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• 1999

The use of thick plate in increasing in recent years due to the rapid expansion of chemical plants, nuclear plants, ships and other industrial plants. Welding is the most popular joining techniques employed in manufacturing industrial machineries and structures. Normally, Groove shapes are prepared according to appropriate rules and regulations such as KS, JIS, AWS, LR, DNV and etc. for various thicknesses of plate. However those groove angles tend to be too large. As a result of large groove angle, residual stress, deformation of material and strength reduction is obtained. Therefore, the reliability and safety of structures and machinery tend to be decreasing. Therefore, in this paper, theoretical as well as experimental study are carried out to find optimum groove shapes for T-welded joint of mild steel. The test specimen are made in same condition with simulation model. Welding residual stresses measurement by sectional cutting method. ⅰ) The mechanical difference for change the thickness of plate and groove angle are not appeared. ⅱ) In a mechanical point of view minimum preparation angle(40°) is more suitable than maximum groove angle(60℃). ⅲ) The measurement value and distribution of welding residual stresses are not effected largely by groove angle. It is mechanical restraint that mainly affect welding residual stresses distribution. In mechanical point of view minimum groove angle is more suitable than maximum groove angle. Therefore, it is appropriate to minimize the size of groove shape in strength and safety.

• The KIPS Transactions:PartB
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• v.13B no.2 s.105
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• pp.83-88
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• 2006

Digital image processing algorithm was proposed to measure the area inside of an object image using angle-distance graph used to analyze the pattern of an object in the digital image processing techniques. The first angle-distance graph is generated from a point inside of an object area. The second angle-distance graphs are generated for the areas missed in the first graph by extracting the positions with large gradient in the first angle-distance graph. The order of the graph increases according to the complexity of an object pattern. Size of the area inside of an object boundary is measured by integrating square of distance multiplied by angle for each area from the hierarchical angie-distance graphs.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.5
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• pp.263-271
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• 2003

Effects of the existence of $CO_2$ gas and pH on the silica surface characteristics at silica/Pb(II) and sodium dodecyl sulfonate (SDS, $C_{12}H_{25}SO_3Na$) solution interface were studied. The hydrophobic characteristics of silica surface was delineated by contact angle measurement and surface force measurement using atomic force microscopy (AFM). In $CO_2$ free condition provided by purging $N_2$ gas, the contact angle of fused silica surface in $10^{-4}M$ Pb(II) and SDS solution increased greatly up to $90^{\circ}$ compared with $40^{\circ}$ in atmospheric condition. It was due to the precipitation of $PbCO_3$ in atmospheric condition. In $CO_2$ free condition the change of contact angle and adhesion force ($F_{ad}$) in AFM, affected by pH change, was similar to the distribution of $PbOH^+$ ion in speciation diagram corresponding to $10^{-4}M$ total Pb(II). Therefore, it was convinced that the $PbOH^+$ ion among Pb(II) species would be the main adsorbing type on silica surface. Both of contact angle measurement and surface force measurement using AFM showed that the Pb only treatment made the silica surface hydrophobic. However, it could not be explained theoretically by current knowledge, and required further study in atomic level to solve the problem.

• Journal of the Ergonomics Society of Korea
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• v.23 no.2
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• pp.1-12
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• 2004

The purposes of this study were to investigate the relationship between anthropometric data of foot and other body sizes. to categorize the foot shape of elementary school boys and to find out determinant factors related the foot that enable us to deduce the foot shape and size for the design of more comfortable shoes. Subjects of this study were 249 elementary school boys of age ranged from 6 to 11 residing Seoul and lncheon area. Anthropometric sizes were measured with the direct measurement method using Martin scales and the indirect measurement method using digital photos. Pearson's correlation, factor analysis. cluster analysis. analysis of variance, post-hoc test, and cross tabs were performed for statistical analysis of the data by SPSS program. From the investigation on the relationship between foot-related items and body items, most items of foot measure were significantly related to body size items. However, angle of the foot did not related to other body sizes although other height items and mass items of the foot did have relationships with other body sizes. Results of ANOVA indicated there were significant differences in foot-related items except for items of foot angle and all body anthropometric items by subjects' age. This implicates big toe angle, little toe angle and foot ratio factors are required in sizing shoes besides foot length. On the basis of cluster analysis using factor scores. three different foot shapes were categorized. Type 1 was large and wide foot, Type 2 was small and narrow foot with large toe angle. and Type 3 was medium foot with no deformity on big toe. These three groups show significant differences in almost all measurement items. However, Rorher index and foot angle didn't show any significant differences among groups. This implicates the foot shape can be a determinant of shoe size.

• The Journal of the Acoustical Society of Korea
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• v.25 no.2E
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• pp.60-68
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• 2006

High-frequency bistatic scattering measurements from a corrugated surface were made in an acoustic water tank. First the azimuthal scattering pattern was measured from an artificially corrugated surface which has varying impedance. The corrugated surface was installed both transverse to the direction of incident wave and longitudinal to the direction of incident wave. The angle between the corrugated surface and the direction of the incident wave was about $45^{\circ}$. Second, the scattering strengths were measured from the flat sediment and the corrugated sediment. A critical angle of about $37^{\circ}$ was calculated in the acoustic water tank. The measurements were made at three fixed grazing angles: $33^{\circ}$ (lower than critical angle), $37^{\circ}$ (critical angle), and $41^{\circ}$ (higher than critical angle). The scattering angle and the grazing angle are equal in each measurement. Frequencies were from 50 kHz to 100 kHz with an increment of 1 kHz. The corrugated sediment was made transverse to the direction of the incident wave. The first measurement indicates that the scattering patterns depend on the relations between the corrugated surface and the direction of the incident wave. In the second measurement, the data measured from the flat sediment were compared to the APL-UW model and to the NRL model. The NRL model's output shows more favorable comparisons than the APL-UW model. In case of the corrugated sediment, the model and the measured data are different because the models used an isotropic wave spectrum of sediment roughness in the scattering calculations. The isotropic wave spectrum consists of $w_2$ and ${\gamma}_2$. These constants derived from sediment names or bulk size. The model which used the constants didn't consider the effect of a corrugated surface. In order to consider a corrugated surface, the constants were varied in the APL-UW model.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.19 no.1
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• pp.105-121
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• 1989

The author analysed tomograms and submento-vertex radiograms of 90 temporomandibular joints from 45 asymptomatic young adults. 15 had Angle class Ⅰ malocclusion, 15 classⅡ and 15 class Ⅲ. Corrected lateral tomograms were obtained in three condylar positions; centric occlusion, centric relation and 1 inch mouth opening. The condylar angulation, depth of cut, joint spaces were analysed in each radiogram. The obtained results were as follows; 1. The mean condylar angulation in Angle class Ⅰ, Ⅱ, Ⅲ group was 17.55±5.51° 13.33±8.85° 16.25±6.60° respectively, and there was no significant difference in each group. The mean condylar angulation of right side (16.62±7.23°) was larger than left side (14.80±7.33°). 2. The mean depth of cut in Angle class Ⅰ, Ⅱ, Ⅲ group was 8.13±1.61㎝, 3.05±3.80㎝, 7.75±2.19㎝, respectively. Angle class Ⅰ and class Ⅱ group revealed significant difference in measurement (p<0.0l). 3. The mean height of articular fossa in Angle class Ⅰ, Ⅱ, Ⅲ group was 8.67±3.06㎜, 9.61±2.57㎜, 8.93±2.83㎜, respectively. And the mean width of articular fossa was 19.90±2.80㎜, 19.48±3.83㎜, 20.36±4.82㎜, respectively. 4. The mean height and width of condylar head was 5.11±1.16㎜, 11.20±2.26㎜, respectively. 5. In centric occlusion, the superior joint space was the largest (3.42±1.42㎜), followed by anterior joint space (2.94±1.95㎜) and the posterior joint space (2.64±1.19㎜. In centric relation, the anterior joint space was the largest (3.86±2.17㎜), followed by the superior joint space (3.64±3.68㎜) and the posterior joint space (1.18±0.77㎜). 6. The displaced measurement from centric relation to centric occlusion was 1.10±1.04㎜ anteriorly and 0.24±0.97㎜ inferiorly. In 1 inch mouth opening state, the condylar head displaced posteroinferiorly (2.49±2.49㎜ posteriorly, 1.17±1.34㎜ inferiorly) from the apex of articular eminence. And Angle class Ⅰ and Ⅱ group, Angle class Ⅱ and Ⅲ group revealed significant difference in posterior measurement, respectively (p<0.01).

• The Journal of Korean Physical Therapy
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• v.31 no.1
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• pp.35-39
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• 2019

Purpose: The purpose of this study was to assess the intra-rater and inter-rater reliability and validity of pelvic tilting angle measurements using a smart phone-based inclinometer (Clino) compared to a palpation meter (PALM) in the standing and sitting position. This study used an interchangeable method with Clino to measure the pelvic tilting angle in the standing and sitting positions. Methods: Twenty healthy subjects were recruited. Measurements of the pelvic tilting angle in the standing and sitting positions were obtained by two examiners using the Clino and PALM. A resting session was conducted 10 minutes later to assess the intra and inter rater reliability. To assess validity of the measurement using Clino, a PALM was used as the gold standard. The intra-class correlation coefficient (ICC) was used to determine the intra and inter rater reliability of Clino and a PALM. To assess the validity, the Pearson correlation coefficients were used for two measurement techniques to measure the pelvic tilting angle in the standing and sitting positions. The statistical significance was set to ${\alpha}=0.05$. Results: Measurements of the pelvic tilt had high inter-rater reliability in the standing (ICC=0.82) and sitting (ICC=0.88) positions using Clino and intra-rater reliability in the standing (ICC=0.87) and sitting (ICC=0.91) positions using Clino. Measurements of the pelvic tilt had high validity by a comparison of PALM and Clino in the standing (r=0.83) and sitting (r=0.89) positions (p<0.05). Conclusion: The use of Clino can be recommended as a tool to replace the PALM and measure the pelvic tilt angle in the standing and sitting positions while maintaining the clinical reliability and validity.

• Physical Therapy Rehabilitation Science
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• v.11 no.4
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• pp.454-463
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• 2022

Objective: The purpose of this study was to compare concurrent validity and test-retest reliability based on Craniovertebral angle of 'Angles video goniometer', a smart phone application for convenient range of motion measurement, and 'Image J', an analysis software with high reliability and validity. This was conducted to find out whether 'Angle video goniometer' can be used clinically. Design: Cross-sectional study Methods: Fifty subjects were imaged laterally, and the angle of the head and spine was measured using Image J and the Angles video goniometer, respectively, in a resting posture and a chin in posture. The level of concurrent validity between the two measurement methods and the level of inter-rater reliability and intra-rater reliability were analyzed. Results: For forty participants, the concurrent validity between Image J and Angles video goniometer showed very high validity with ICC of 0.997(0.995~0.999) and 0.994(0.994~0.998), CVME% 0.71~0.72%, SEM% 0.31~0.34, MDC% 0.86~0.94. The test-retest intra-rater reliability showed very high reliability ICC 0.994(0.991~0.996), CVME% 0.71%, SEM% 0.31~0.43, MDC% 0.86~1.19%. The test-retest inter-rater showed very high reliability ICC 0.995(0.992~0.997), CVME% 0.71%, SEM% 0.43~0.59%, MDC% 1.20~1.62% Conclusions: Angles video goniometer', a smartphone application, is a device with very high reliability and validity for craniovertebral angle measurement in healthy adults, and it is a device that can be easily used in clinical practice.