• Journal of the Korean Wood Science and Technology
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• v.18 no.4
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• pp.86-101
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• 1990

The primary objective of this research was to investigate the strength properties of Comply, a composite panel. fabricated with particle board as core material and veneer or plywood as face and back. 20types of comply composites were manufactured according to the four specific gravity levels(0.5, 0.6, 0.7 or 0.8) of particleboard core and three veneer or two plywood thicknesses for face and back. They were tested and compared with matching particleboard (control) on moisture content. specific gravity, bending properties(MOE, MOR SPL). nail resistance and internal bond strength. The obtained results were summarized as follows: The increasing effect of modulus of elasticity was shown by the increase of face and back veneer or plywood thickness. The modulus of rupture and stress at proportional limit of the comply composites bonded with 3mm thick veneers or 3mm thick plywood face and back were higher than 2mm thick veneer or 2mm thick plywood as face and back. Both of modulus of rupture and stress at proportional limit on bending of Comply were higher than those of control board. Also the modulus of elasticity of Comply showed much higher than that of control board. The nail resistance of Comply, composed of plywood as face and back was higher than that of veneer. The nail resistance of control board was higher than that of Comply at Sp.Gr 0.7 and 0.8 core boards. Internal bond of Comply, composed of 1mm and 2mm thick veneer as face and back was higher than that of 3mm thick veneer. The increasing effect of modulus of elasticity was shown by the increase of shelling ratio in Comply composed of veneer and plywood as face and back. The modulus of rupture was increased by the increment of shellmg ratio in Compiy, composed of plywood as face and back. The modulus of elasticity and modulus of. rupture of comply were higher than those of particleboard(control) in effect of shelling ratio. Therefore it was concluded that the mechanical property values of Comply were clearly greater than those of particleboard(control).

• Physical Therapy Rehabilitation Science
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• v.11 no.1
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• pp.43-48
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• 2022

Objective: In the present study, to determine the extent of academic stress and pain from sitting for a long time, we will use a questionnaire to examine the effects of non-face-to-face stress and back pain on college students who have conducted non-face-to-face lectures. Design: Survey research Methods: A questionnaire was conducted using Naver foam to identify academic stress, attitude and time to listen to lectures, and the extent of back pain for college students who are experiencing non-face-to-face lectures. Outcome measures include the scale of academic stress (SAS), the Numeric rating scale (NRS), the Oswestry Disability Index (ODI Korea version) was implemented. The difference in academic stress was analyzed by t-test and one-way ANOVA, and the correlation between academic stress and back pain was analyzed using the Spearman correlation coefficient. In order to examine the academic stress, consistency, and stability, the reliability of the academic stress items was measured by examining the reliability with the Cron-Bach alpha coefficient. Allstatistical significance levels were α=0.05. Results: According to the general characteristics of the subject, there were no statistically significant results compared to gender (P<0.05), but the higher the grade, the higher the stress index, the higher the level of pain. Conclusions: This study confirmed that non-face-to-face lectures caused by COVID-19 have increased academic stress and the resulting increase in back pain in college students.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.7
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• pp.1759-1772
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• 1994

In this study, we re-examined the Tate's modified Bernoulli equation to study penetration phenomena for long rod projectile into single or multi-layered finite thickness plates. We used the force equlibrium equation at mushroomed nose/target interface instead of conventional pressure equation at the stagnation point. In our penetration model, we considered the velocity dependent $R_t$ value for semi-infinite target and considered only the back face effect for finite target. To compensate for $R_t$ value according to target's thickness and back face effect, we used the spherical cavity expansion theory for semi-infinite plate and used the cylindrical cavity expansion theory for finite plate. Also we developed the experimental technique using make screen to measure the penetration duration time at each layered plate. In 3-layered laminated RHA/mild steel/ A1 7039 plate, we observed that spall had occured around the back face of A1 7039 plate by the stress wave interaction. Through the comparison between theoretical and experimental data including Lambert's results, we conform that our study has good confidences.

• Journal of Industrial Technology
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• v.28 no.B
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• pp.143-148
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• 2008

A real-time face detection is to find human faces robustly under the cluttered background free from the effect of occlusion by other objects or various lightening conditions. We propose a face detection system for real-time applications using wavelet decomposition method based on Gabor features. Firstly, skin candidate regions are extracted from the given image by skin color filtering and projection method. Then Gabor-feature based template matching is performed to choose face cadidate from the skin candidate regions. The chosen face candidate region is transformed into 2-level wavelet decomposition images, from which feature vectors are extracted for classification. Based on the extracted feature vectors, the face candidate region is finally classified into either face or nonface class by the Levenberg-Marguardt back-propagation neural network.

• The Korean Journal of Emergency Medical Services
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• v.20 no.3
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• pp.49-56
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• 2016

Purpose: The purpose of this study was to investigate the effect of a pathogenic bacteria filtration instrument for infection prevention during mouth-to-mouth ventilation. Methods: Two kinds of face shields were used for the study. One rescuer blew the filter through a bag valve mask and the filter was then cultured for bacteria. The mask was tested both on the front and back side. Results: Two kinds of face shields including the KF shield and CM shield were tested. The KF shield has received national certification and it prevented transmission of bacterial infection but the CM shield showed the opposite result and did not prevent bacterial transmission. Pathogenic bacteria were found on the back of the CM shield. Conclusion: A certified face shield is very important to prevent bacterial transmission. Face shields should be demonstrated and used by paramedic students.

• Journal of the Institute of Convergence Signal Processing
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• v.7 no.3
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• pp.95-101
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• 2006

A face detection plays an important role in face recognition, video surveillance, and human computer interaction. In this paper, we propose a progressive threshold method to detect human faces in real time. The consecutive face images are acquired from camera and transformed into YCbCr color space images. The skin color of the input images are separated using a skin color filter in the YCbCr color space and some candidated face areas are decided by connected component analysis. The intensity equalization is performed to avoid the effect of many circumstances and an arbitrary threshold value is applied to get binary images. The eye area can be detected because the area is clearly distinguished from others in the binary image progressive threshold method searches for an optimal eye area by progressively increasing threshold from low values. After progressive thresholding, the eye area is normalized and verified by back propagation algorithm to finalize the face detection.

• Journal of Magnetics
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• v.12 no.3
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• pp.118-123
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• 2007

We have studied the effect of Au-Cu back layer system ${\sim}10{\AA}$ thick on the properties of a spin valve. The back layers were Cu, Au, co-sputtered $Cu_xAu_{1-x}$, laminated $[Au/Cu]_n$. and bi-layer [Au/Cu]. When Au was added to the Cu, the resistance of the spin valve abruptly increased most likely due to impurity scattering. The GMR values were not increased significantly for all the structures. In the case of co-sputtered $Cu_xAu_{1-x}$, the changes in the resistance, ${\Delta}R$, was increased at a composition of ${\sim}Au_{0.5}Cu_{0.5}$. This increase in ${\Delta}R$ is due to increase in the resistance and not from the enhanced spin-dependent scattering. The structural analyses showed that the orthorhombic $Au_{0.5}Cu_{0.5}$ was formed in the back layer instead of the face-centered tetragonal $Au_{0.5}Cu_{0.5}$ as we expected. Thermal annealing over $400^{\circ}C$ may be required to have face-centered tetragonal in the $10{\AA}$ thick ultra-thin film. In the case of a laminated or bi-layered back layer, the properties of the spin valve were improved, which may be attributed to the increase in the mean free path of conduction electrons.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.8 no.1
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• pp.1-5
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• 2010

Purpose : This research inquires into the effect of applying microcurrent (MC) according to various frequency levels on the pain and functional recovery of patients with chronic back pain. Methods : Thirty participants with chronic lower back pain disease were divided equally into three experimenta l groups. The MC frequency used in the first experimental group was 0.5Hz, the second experimental group was 50Hz, and the third experimental group was 100Hz for 20 minute sessions. A hot pack and ultrasound were applied to all groups as the general physical therapy. Measurements were taken using the visual analogue scale (VAS), the face pain rating scale (FPRS), and the Oswestry disability index (001). The analysis used the paired t-test in order to compare pretest and posttest results. A one-way ANOVA was performed to make comparisons with regards to frequency levels. Results : VAS, FPRS, and 001 showed significant pain decrease in all groups except for the 001 measurement in the 0.5 Hz group. There were no significant differences according to frequency levels. Conclusion: For chronic pain and functional recovery, a microcurrent produces an effect after treatment. However, results did not show a significant difference in change obtained from differing frequency levels.

• Journal of The Korean Society of Integrative Medicine
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• v.10 no.3
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• pp.131-140
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• 2022

Purpose : Although many studies have explored the effect of seating side angles on the spinal curve and surrounding muscles during seating, only a few studies have investigated the effect of different seating face angles on different lower limb and deep trunk muscles. Therefore, this study investigated the effects of seating surface angles (0 degrees, 10 degree anterior, and 10 degree rear) on lower extremity and deep trunk muscles in healthy adults. Methods : Thirty people were asked to sit once on each seating surface three times during the day, and their muscle thicknesses were measured by ultrasound while sitting. The method of sitting was the same when sitting on the three seating surfaces. Results : From the comparison results of the muscle thicknesses according to the seating surface angles, a significant difference existed in the muscle thicknesses of the vastus medialis, vastus medialis oblique, vastus intermedius, soleus and gastrocnemius (p<.05). However, no significant difference was found in the transversus abdominis, internal obliques, rectus femoris and vastus lateralis (p>.05). Conclusion : Our findings revealed that the lower back load decreases, the leg load increases, and the legs specific muscles are affected as the body tilts forward when sitting on the seating surface inclined forward. Therefore, it is possible to suggest a forwardly inclined seating surface that reduces lower back loads and utilizes the posture-maintaining muscles of the legs when sitting in a person with a poor sitting posture or lower back pain at ordinary times.

• Journal of the Korean Geosynthetics Society
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• v.17 no.1
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• pp.139-152
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• 2018

This study is an analysis of slope failure examples of cut sedimentary hills during construction road in Kyoungsang Basin, especially Yangsan Fault system (Ilkwang-Dongrae fault). This area involved a lot of hillslope failures compared to other areas during road construction. The exposed failure slopes were first face-mapped, and then back analyzed based on the limit equilibrium method to assess the shear strength parameters of discontinuity (bedding). The results of this analysis indicate that the shear strength parameters of discontinuity (bedding) are significantly smaller than those used in the design stage and presented in the existing works. The filling in the bedding and emerging groundwater may be decreasing strength parameters. Especially, the clay in the bedding plays a key role in the effect of the shear strength. The study also suggests that the bedding angle and the internal friction angle are proportional to each other. Using this relationship and knowing the bedding angle, the friction can easily be estimated.