• Physical Therapy Korea
• /
• v.26 no.1
• /
• pp.19-27
• /
• 2019

Background: Compared to healthy people, patients with chronic lower back pain have reduced balance abilities which may cause proprioception problems, patients with chronic lower back pain avoid physical activities due to pain, and reduced activity levels lead to muscle weakening, which can further exacerbate pain. Recently, there have been many studies on the use of sensory stimulation; and among these studies, interventions that use vibrational stimulation have shown functional improvements in the patients. Objects: This study examined the effects of a stabilization exercise with vibration stimulation on the balance ability and disability in patients with chronic back pain. Methods: The subjects of the study were 30 persons who were randomly assigned to the experimental group and the control group, with 15 subjects in each. The subjects were evaluated before and after intervention via a balance ability test, the Korean Oswestry disability index (KODI) test, a pain test, and a proprioceptive sensory test. Both groups received general physical therapy. The experimental group performed the stabilization exercise with vibration stimulation, and the control group performed a general stabilization exercise, three times a week for six weeks. Results: After the intervention, both groups showed significant improvements in the balance ability test, the KODI test, the pain test, and the proprioceptive sensory test. The experimental group showed statistically significant, higher improvements than the control group in the balance ability test, the KODI test, and the proprioceptive sensory test. Conclusions: The stabilization exercise with vibration stimulation for patients with chronic back pain has been reported to provide greater functional improvements than the conventional intervention method. Therefore, the stabilization exercise in a vibration stimulation environment could be a useful intervention for patients with chronic back pain.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.9 no.3
• /
• pp.287-294
• /
• 2021

In this study, tests were performed to analyze the feasibility of using the ground stabilizer from recycled resources such as blast furnace slag powder as filling material of prebored piles. For this, specimens were prepared by applying 70% and 83% of the general water/binder ratio of the filling material of prebored piles. And compression test, model test, and shaking table test were performed to determine the compressive strength, skin friction on the surface between prebored pile and filling material, and seismic performance of ground stabilizer. As a result of the tests, the compressive strength exceeded the relevant domestic standards, and the skin friction was equivalent to that of ordinary portland cement. In addition, the amount of vertical and horizontal displacement caused by earthquakes was found to be much smaller than the domestic standard. Therefore, when considering the test results comprehensively, it is judged that the feasibility of using a ground stabilizer from recycled resources as filling material for prebored pile is sufficient.

• Journal of the Korean Chemical Society
• /
• v.64 no.6
• /
• pp.334-344
• /
• 2020

The adsorption of various atmospheric harmful gases (COx, NOx, SOx) on graphene-like Germanene 2D sheet was theoretically investigated using density functional theory(DFT) method. The structures were fully optimized at the B3LYP/cc-pvDZ and CAM-B3LYP/cc-pvDZ levels of theory and confirmed to be a local minimum by the calculation of the harmonic vibrational frequencies. The adsorptions of gases on the Germanene sheet were predicted to be a physisorption process for CO, CO2, NO, and SO2 gases but to be a chemisorption process for NO2, SO, and SO2 gases.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.21 no.4
• /
• pp.129-134
• /
• 2021

A power tool is a tool used to manufacture and process various structures using a motor that is a power source. Using a motor that uses electricity as a power source, a reduction device, power transmission and conversion device functions are built-in to make the tool rotate, reciprocate, and vibrate. It is a work tool designed to assist the user's movement skills. In the case of Korea, the power tool industry has a short history and is lagging behind advanced countries such as Germany, the United States, and Japan in terms of technology level, market share, and recognition. In addition, electric drivers used in Korea are foreign products from the US and European countries, and the domestic market also prefers 100% foreign companies, and multinational companies are investing a lot in the domestic market. Therefore, technological development must follow in order to develop domestic technology and secure a consistently high market share. The purpose of this thesis is to design a motor driver with high output performance of motor performance, miniaturization, and high speed in accordance with the basic performance requirements of power tools, and finally research developments that can be applied to industrial and medical applications.

• Journal of the Microelectronics and Packaging Society
• /
• v.29 no.1
• /
• pp.7-16
• /
• 2022

Recently, the automobile industry is rapidly changing due to technological development. Next-generation cars with high technology and new functions are on the market. It is essential to develop electronic devices to meet the condition of next-generation cars. In this study, the authors have reviewed recent trends of automotive electronics and packaging technology. Automotive electronics are used in harsh environments compared with other industries. Thus, it is important to improve the reliability of device junctions that directly affect electronics performance. Soldering, TLP (transient liquid phase bonding), and sintering are introduced for the bonding methods in car electronics.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.22 no.5
• /
• pp.111-116
• /
• 2022

The causes of motor burnout include overload, phase loss, restraint, interlayer short circuit, winding ground fault, instantaneous overvoltage, and the rotor contacting the stator, leading to insulation breakdown, leading to breakdown or electrical accidents. Therefore, equipment failure causes not only loss due to cost required for equipment maintenance/repair, but also huge economic loss due to productivity decrease due to process stop because the process itself including the motor is stopped. The current level of technology for diagnosing motor failures uses vibration, heat, and power analysis methods, but there is a limit to analyzing the problems only after a considerable amount of time has passed according to the failure. Therefore, in this paper, a device and algorithm for measuring insulation resistance using DC AMP signal was applied to an industrial motor to solve this problem. And by following the insulation resistance state value, we propose a diagnosis of deterioration and failure of the motor that cannot be solved by the existing method.

• The Journal of the Acoustical Society of Korea
• /
• v.28 no.1
• /
• pp.44-50
• /
• 2009

While American acoustics had been lagged behind European one in the nineteenth century, Alfred Mayer greatly contributed to enhance American experimental acoustics. He inherited experimental skills in collaboration with Koenig in Paris, and got chances to obtain research ability from leading researchers such as Rayleigh during his visit to England. His accomplishments, which brought him fame in Europe, included the creation of the acoustic pyrometer which measured the high temperature by means of the thermal change of the sound velocity, the discovery of mosquito's hearing by selective resonance, the formalization of the duration of the residual sensation of sound, the invention of the topophone which searched for the direction of the sound source, the construction of the apparatus for visualizing the frequency of sound and so on. He not only added new research results to Europe's acoustics but applied acoustics to physical education to help produce the next generation of American acousticians.

• Tunnel and Underground Space
• /
• v.34 no.2
• /
• pp.143-153
• /
• 2024

Tunnel Boring Machine (TBM) method is a tunnel excavation method that produces lower levels of noise and vibration during excavation compared to drilling and blasting methods, and it offers higher stability. It is increasingly being applied to tunnel projects worldwide. The disc cutter is an excavation tool mounted on the cutterhead of a TBM, which constantly interacts with the ground at the tunnel face, inevitably leading to wear. In this study quantitatively predicted disc cutter wear using geological conditions, TBM operational parameters, and machine learning algorithms. Among the input variables for predicting disc cutter wear, the Uniaxial Compressive Strength (UCS) is considerably limited compared to machine and wear data, so the UCS estimation for the entire section was first conducted using TBM machine data, and then the prediction of the Coefficient of Wearing rate(CW) was performed with the completed data. Comparing the performance of CW prediction models, the XGBoost model showed the highest performance, and SHapley Additive exPlanation (SHAP) analysis was conducted to interpret the complex prediction model.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.35 no.6
• /
• pp.683-689
• /
• 2006

This study was established to investigate the effect of germanium-fortified yeasts on the serum lipid composition and immune system of human body. All 50 subjects with the age range of $50{\sim}75$ were entered in this clinical trial for 6 months. The effects were determined by the proliferative responses of immune-mediated cells, T-cell, B-cell and NK-cell during daily supplementation with/without germanium-fortified yeast. The results of hematology and blood chemistry didn't show any significant differences during administration periods. Serum lipid compositions also didn't show any significant differences during administration periods except triglyceride (TG) and VLDL-cholesterol. TG and VLDL-cholesterol levels were increased significantly by the consumption of germanium-fortified yeast (p<0.05). Immune mediated T-celt and NK-cell didn't increased in both control and test group supplemented with germanium fortified yeast, while B-cell increased in the germanium fortified yeast group after 8 week (p<0.05). Also $TNF-{\alpha}$ increased in the group of germanium fortified yeast after 8 week (p<0.05) but not in the control group. From the above results, germanium fortified yeast is expected to be useful on the improvement of the cellular immune response and protection of organs from various chronic diseases.

• Journal of dental hygiene science
• /
• v.9 no.4
• /
• pp.453-459
• /
• 2009

The purposes of this research were to evaluate the relationships of between characteristics of noise and annoyance of dental hygienist by noise in dental clinic. To investigate the dental clinic workers' reactions to noise when occurred in dental clinic, the noise level test in dental clinic and questionnaire were taken. As a result of noise evaluation, It shows that the range of noise level was 67.7~78.3dB(A) and frequency was very high (more than 4KHz). It's seem to be begins occurrence of stamina-loss, contraction of peripheral blood vessel, decrease of adrenocortical hormones. Most of respondents were affected by noise: 67% of respondents were nervous about noise and the rest of respondents were bearable. Analysis by NR-curve showed that it was exceed the noise permit level in working space. As a result of correlation - test, the more exposed dental hygienist to noise, the more felt the unpleasantness and fatigue. It's hard to sufficient explanation to patients about the dental treatment. So it's thoughts that insufficient explanation will negative impact on the patients' satisfaction and increase competitiveness in dental clinics. To remedy a unpleasantness and fatigue of noise in dental hygienist, it's considered that making an offer the ear protection and choosing the low noise-vib. equipment and using the masking effect. Therefore, It can be provide a pleasant working environment with dental hygienist and It will have a great advantage to dental clinics to improve their competitiveness.