• Journal of the Korean Wood Science and Technology
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• v.48 no.4
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• pp.562-568
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• 2020

This study investigates the relationship between ultrasonic velocity and density in the direct method, the effect of distance between transducers in the indirect method, and the difference between the direct and indirect methods with transducers placed at a distance of 200 mm in nondestructive ultrasonic testing of spruce lumber. The direct method using 54 kHz ultrasonic transducers was applied to two planes, namely, radial section (LR) and tangential section (LT) of samples. The indirect method measurements were taken using the same transducers. Two velocities were measured at the top and bottom of the LT plane and at the two sides of the LR plane; the two values for each plane were averaged. The relationship between density and ultrasound velocity in the direct method demonstrated a positive correlation between the two variables. The difference between the two planes, LT and LR, was not statistically significant. Moreover, the distance between the transducers in the indirect method affected ultrasound velocity, with the ultrasonic velocity increasing as the distance between the transducers became larger. A transducer distance of 200 mm yielded a close approximation of the direct method results with a ratio of 0.87. Finally, no statistical evidence of a difference between the two planes in the indirect method was found. If the direct method, which requires access to two surfaces, is impractical, the indirect method can be applied.

• Imaging Science in Dentistry
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• v.34 no.1
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• pp.31-34
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• 2004

Purpose: To compare the size of the masseter and lateral pterygoid muscle between the affected and the unaffected side of the patients who have the chief complaints of the mandibular asymmetry. Materials and Methods: Twenty two patients (male: 4, female: 18, average age: 21.3 year-old) were radiographed using posterior-anterior (P-A) cephalography and computed tomography (CT). On P-A cephalography, the degree of deviation was determined by the distance from the mentum to the vertical reference line through the crista galli and the anterior nasal spine. On the scanned tracing papers of the maximum cross-sectional area of the masseter and lateral pterygoid muscle using axial CT images, the pixel number was measured. The ratio of the affected : unaffected sides were obtained. For the masseter and lateral pterygoid muscle, the relationship between the muscular volume and degree of skeletal hypoplasia was studied. Results : The half cases showed no skeletal asymmetry. The lateral pterygoid muscle of the affected side was larger significantly than unaffected side (p<0.05). However, there was no significant difference between two sides in the cases of skeletal asymmetry. There was only significant difference in the cases without skeletal asymmetry (p<0.05). Conclusions : To some extent, the slight mandibular hypoplasia could affect the growth of some masticatory muscles.

• Journal of Biosystems Engineering
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• v.26 no.2
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• pp.147-154
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• 2001

In Korea and Japan, dried oak mushrooms are classified into 12 to 16 different categories based on its external visual quality. And grading used to be done manually by the human expert and is limited to the randomly sampled oak mushrooms. Visual features of dried oak mushrooms dominate its quality and are distributed over both sides of the gill and the cap. The 2nd prototype computer vision based automatic grading and sorting system for dried oak mushrooms was developed based on the 1st prototype. Sorting function was improved and overall system for grading was simplified to one stage grading instead of two stage grading by inspecting both front and back sides of mushrooms. Neuro-net based side(gill or cap) recognition algorithm of the fed mushroom was adopted. Grading was performed with both images of gill and cap using neural network. A real time simultaneous discharge algorithm, which is good for objects randomly fed individually and for multi-objects located along a series of discharge buckets, was developed and implemented to the controller and the performance was verified. Two hundreds samples chosen from 10 samples per 20 grade categories were used to verify the performance of each unit such as feeding, reversing, grading, and discharging unites. Test results showed that success rates of one-line feeding, reversing, grading, and discharging functions were 93%, 95%, 94%, and 99% respectively. The developed prototype revealed successful performance such as the approximate sorting capability of 3,600 mushrooms/hr per each line i.e. average 1sec/mushroom. Considering processing time of approximate 0.2 sec for grading, it was desired to reduce time to reverse a mushroom to acquire the reversed surface image.

• Journal of Korean Society of Steel Construction
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• v.24 no.6
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• pp.735-742
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• 2012

This paper presents the experimental results of axially loaded stub columns of slender steel hollow square section(SHS) strengthened with carbon fiber reinforced polymers(CFRP) sheets. 6 specimens were fabricated and the main parameters were: width-thickness ratio(b/t) and CFRP retrofitting. From the tests, it was observed that two sides would typically buckle outward and the other two sides would buckle inward. A maximum increase of 33% was achieved in axial-load capacity. Also, stiffness and ductility index(DI) were compared between unretrofitted specimens and retrofitted specimens. In the last section, a prediction formula of the ultimate strength developed using the experimental results is presented.

• Ocean and Polar Research
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• v.36 no.4
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• pp.447-454
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• 2014

In August, 2013, we collected epifaunal megabenthos using a deep sea camera (DSC) around a benthic impact study (BIS) site. This was located in the KR5 block of the Korea Deep Ocean Study (KODOS) area in the Northeastern Pacific. The DSC was positioned at $6.8{\pm}2.9m$ (SD) from the sea bottom and was operated from a position at $131^{\circ}56.85^{\prime}-131^{\circ}55.02^{\prime}W$ for 2.3 h at a speed of 1-2 knot. The geographical features of the study area consisted of two structures; a trough in the middle and hills at the east and west sides. Sediment conditions were consistent within six blocks and were affected by slope and polymetallic nodule deposits. We analyzed 226 megafaunal species. Sipunculida comprised the highest percentage of individuals (39%), and the dominant epifaunal megabenthos were Hormathiidae sp., Primnoidae sp., Hexactinellida sp., Hyphalaster inermis, Freyella benthophila, Paelopatides confundens, Psychropotes longicauda, and Peniagone leander. More than 80% of the total density of megafauna occurred on sea plain (D- and E-blocks). We found two distinct groups in the community, one located on sea plains and the other along both sides of the sea slop. Our results suggest that geographical features such as slope and polymetalic nodule deposits are important in controlling the distribution of the epifaunal megabenthos around the KODOS area.

• The korean journal of orthodontics
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• v.48 no.2
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• pp.73-80
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• 2018

Objective: This retrospective study compared the three-dimensional (3D) structure of mandibular condyles between adults with and without facial asymmetry, and whether it influences menton deviation. Methods: Sixty adult patients were classified into symmetry and asymmetry groups based on the menton deviation on postero-anterior radiographs. The right/left differences of 3D measurements were compared between the two groups, and measurements were compared separately on the right and left sides. The correlations between menton deviation and the right/left differences were analyzed. Results: The mediolateral dimension, neck length, condylar angles to the anteroposterior reference (PO) and midsagittal reference planes, and neck and head volumes showed significantly larger right/left differences in the asymmetry group compared to the symmetry group. Separate comparisons of the right and left sides between the two groups showed that the neck was significantly shorter and neck and head volumes were significantly smaller on the left side, which was deviated side in the asymmetry group. Pearson's correlation analysis showed significant positive correlations of menton deviation with right/left differences in neck length, condylar angle to the PO plane, and neck and head volumes in the asymmetry group. Conclusions: In individuals with facial asymmetry, menton deviation is associated with the right/left differences caused by a smaller condyle on the deviated side, particularly in neck length and neck and head volumes.

• Korean Journal of Social Welfare
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• v.36
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• pp.259-283
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• 1998

This research is based on the assumption that Korea's social consensus among two sides of industry and government on Feb. 2 '98 was not just temporary response to the economic crisis caused by International Monetary Fund financial fund. Some arguments on the applicability of social democracy and corporatism and D. Donnison's perspective on Democratic Socialism are employed in search of an appropriate social consensus model for Korean situation. In the process of analyzing Korean situation in historical context it becomes apparent that there is embryo of stable social consensus beyond the level of tentative social cooperation to overcome the economic crisis. The next step applying the social consensus model to the employment policy for people with disability levels up empirical and theoretical validity of this research. It casts some implications for disability labour market which demands another kind of social consensus among people with disability, employers and the government. These implications include a desirable solution for hard lives of unemployed people with disability in economic difficulties and current policy issues facing Korean government.

• Journal of the Korean Society of Physical Medicine
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• v.11 no.4
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• pp.127-137
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• 2016

PURPOSE: This study aimed to compare the effects of side-lying hip abduction exercise with and without vibration on pain, disability, strength and balance in individuals with low back pain. METHODS: 30 participants enrolled in this study were randomly assigned to an experimental group (EG, n=15) for side-lying hip abduction with vibration and a control group (CG, n=15) for side-lying hip abduction without vibration. Both groups were treated 3 times per week for 4 weeks. Pain (Numeric Rating Scale), disability (Korean Oswestry Disability Index), hip abductor muscle strength, and static balance were measured in both groups before and after the program. Results were analyzed using paired t-test for comparing the difference within the group and independent t-test for comparing the difference between two groups. RESULTS: Compared to the CG, the EG showed significantly greater reductions in pain and disability (p<.05). There was a significant difference in all balance categories of both the painful and non-painful sides within the EG (p<.05). Balance showed a significant decrease except the envelope area (ENV) on the non-painful side within the CG (p<.05). There was a significant increase in all balance categories except ENV of non-painful side between the two groups (p<.05). Balance increased on both the painful and non-painful sides in the EG. Balance improved on the painful side in the CG, but significantly decreased on the non-painful side (p<.05). CONCLUSION: Side-lying hip abduction exercise with vibration is considered an effective treatment for pain, disability and balance in individuals with low back pain.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.147-152
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• 2006

Restoration of historical documents and arts has become important to inherit cultural properties. Most of historical documents were recorded on paper. Therefore, restoration of ancient papers is demanded and techniques for this purpose must be developed and sophisticated. In our study, several nondestructive methods for analyzing ancient paper have been developed. Image analysis using fast Fourier transform with suitable modifications was applied to optical micrographs of traditionally-handmade Korean and Japanese papers. This analysis determines the angle and anisotropy of fiber orientation of paper surfaces. Fiber orientation of traditionally-handmade Korean and Japanese papers was found to show their own characteristics in accordance with the motion of a papermaking screen made of bamboo splints. Consequently, the information on fiber orientation was found to be possible to distinguish the flow-sheet forming typical of Japanese paper and still-sheet forming typical of Korean paper. Moreover, the anisotropy was always higher for the screen side than for the top side, thus meaning that surface fiber orientation is possible to distinguish the two sides of paper of which papermaking history is unknown. An application of this technique to actual historical documents evidenced that wrapping papers were used as envelops with a lateral side up, namely, after rotating 90 degrees. A variety of cultural habits in writing letters was revealed by discrimination of the two sides.

• Steel and Composite Structures
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• v.7 no.6
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• pp.457-468
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• 2007

Analytical and experimental investigation on dynamic properties of extra lightweight concrete sandwich beams reinforced with various lay ups of carbon reinforced epoxy polymer composites (CFRP) are discussed. The lightweight concrete used in the core of the sandwich beams was made up of extra lightweight aggregate, Lica. The density of concrete was half of that of the ordinary concrete and its compressive strength was about $100Kg/cm^2$. Two extra lightweight unreinforced (control) beams and six extra lightweight sandwich beams with various lay ups of CFRP were clamped in one end and tested under an impact load. The dimension of the beams without considering any reinforcement was 20 cm ${\times}$ 10 cm ${\times}$ 1.4 m. These were selected to ensure that the effect of shear during the bending test would be minimized. Three other beams, made up of ordinary concrete reinforced with steel bars, were tested in the same conditions. For measuring the damping capacity of sandwich beams three methods, Logarithmic Decrement Analysis (LDA), Hilbert Transform Analysis (HTA) and Moving Block Analysis (MBA) were applied. The first two methods are in time domain and the last one is in frequency domain. A comparison between the damping capacity of the beams obtained from all three methods, shows that the damping capacity of the extra lightweight concrete decreases by adding the composite reinforced layers to the upper and lower sides of the beams, and becomes most similar to the damping of the ordinary beams. Also the results show that the stiffness of the extra lightweight concrete beams increases by adding the composite reinforced layer to their both sides and become similar to the ordinary beams.