• The Journal of Industrial Distribution & Business
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• v.11 no.3
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• pp.39-50
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• 2020

Purpose: Agriculture, which is heavily influenced by climate conditions, is one of the industries most affected by climate change. In this respect, various studies on the impact of climate change on the agricultural market have been conducted. Since climate change is a long-term phenomenon for more than a decade, long-term projections of agricultural prices as well as climate variables are needed to properly analyze the impact of climate change on the agricultural market. However, these long-term price projections are often major constraints on studies of climate changes. The purpose of this study is to analyze the impacts of climate changes on the Korean onion market using ex-post analysis approach in order to avoid the difficulties of long-term price projections. Research design, data and methodology: This study develops an annual dynamic partial equilibrium model of Korean onion market. The behavioral equations of the model were estimated by OLS based on the annual data from 1988 to 2018. The modelling system is first simulated to have actual onion market conditions from 2014 to 2018 as a baseline and then compared it to the scenario assuming the climatic conditions under RCP8.5 over the same period. Scenario analyses were simulated by both comparative static and dynamic approach to evaluate the differences between the two approaches. Results: According to the empirical results, if the climate conditions under RCP8.5 were applied from 2014 to 2018, the yield of onion would increase by about 4%, and the price of onion would decrease from 3.7% to 17.4%. In addition, the average price fluctuation rate over the five years under RCP8.5 climate conditions is 56%, which is more volatile than 46% under actual climate conditions. Empirical results also show that the price decreases have been alleviated in dynamic model compared with comparative static model. Conclusions: Empirical results show that climate change is expected to increase onion yields and reduce onion prices. Therefore, the appropriate countermeasures against climate change in Korean onion market should be found in the stabilization of supply and demand for price stabilization rather than technical aspects such as the development of new varieties to increase productivity.

• Environmental Engineering Research
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• v.10 no.6
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• pp.294-305
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• 2005

The effectiveness of fly ash-, quicklime-, and quicklime-fly ash-based stabilization/solidification(S/S) in chromium(Cr) contaminated soils was investigated using modified semi-dynamic leaching tests. Artificial soil samples composed of kaolinite or montmorillonite contaminated with chromium nitrate(4000 mg $Cr^{3+}\;kg^{-1}$ of solid) were prepared and then subjected to S/S treatment using quicklime, fly ash, or quick lime-fly ash. The effectiveness of the treatment was evaluated by assessing the cumulative fraction of leached $Cr^{3+}$ as well as, by computing the effective diffusivity ($D_e$) and the leachability index (LX) of the treated samples. The reduction in $Cr^{3+}$ release for the untreated samples was more pronounced in the presence of montmorillonite, which was attributed to sorption. Treatment with quicklime, fly ash, or quick lime-fly ash was significantly effective in reducing $Cr^{3+}$ release most probably due to the formation of pozzolanic reaction products and $Cr(OH)_3$ precipitation. The most effective treatment was observed in montmorillonite-sand soil samples treated with quicklime-fly ash (99.8% removal). The mean $D_e$ decreased significantly and the mean LX was greater than 9 for all treated samples, indicating that the treated soils were acceptable for "controlled utilization". The mechanism controlling $Cr^{3+}$ leaching from all treated samples during the first 5 days appeared to be diffusion.

• Environmental Engineering Research
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• v.10 no.3
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• pp.112-121
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• 2005

The effectiveness of quicklime-based stabilization/solidification (S/S) in immobilizing lead (Pb) was assessed by performing semi-dynamic leaching tests (ANS16.1). In order to simulate landfill leaching conditions, the ANS 16.1 test was modified by using 0.014 N acetic acid (pH = 3.25) instead of distilled water. Artificial soil samples as well as field soil samples contaminated with Pb were tested. The effectiveness of quicklime treatment was evaluated by determining diffusion coefficients ($D_e$) and leachability indices (LX). A model developed by de Groot and van der Sloat was used to elucidate the controlling Pb leaching mechanisms. Overall, upon quicklime treatment Pb leachability was significantly reduced in a]l of the samples tested. The mean LX values were higher than 9 for an artificial soil sample containing 30% kaolinite treated with 10% quicklime and for a field soil sample treated with 10% quicklime, which suggests that S/S treated soils can be considered acceptable for "controlled utilization". Moreover, quicklime treatment was more effective in artificially contaminated soil with high kaolinite content (30%), indicating the amount of clay plays an important role in the success of the treatment. The controlling Pb leaching mechanism was found to be diffusion, in all quicklime treated samples.

• Physical Therapy Korea
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• v.23 no.1
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• pp.1-10
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• 2016

Background: Patients with chronic low back pain (CLBP) functionally adapt to decreased postural control due to impaired processing of sensory information. Standing postural control has been the focus of recent research in CLBP. Change in postural control may be a risk factor for CLBP, although available studies are not conclusive. Objects: This study aimed to identify the role of partial weight supported treadmill training (PWSTT) in improving balance, dysfunction, and pain in patients with chronic low back pain. Methods: The study included 22 patients with CLBP. Patients in the control group ($n_1=8$) performed three 20 min stabilization exercise sessions per week, for 4 weeks. Patients in the full weight treadmill training group ($n_2=7$) performed treadmill training for 30 min after stabilization exercise. Patients in the PWSTT group ($n_3=7$) performed PWSTT with 20% of their body weight unloaded after stabilization exercises. By using the Biodex balance system, the dynamic balance abilities of the patients in the three groups were assessed in the quiet standing position under combined conditions of visual feedback (eyes open and closed) and platform stability (level 8). The Korean version of the Oswestry Disability Index and visual analogue scale score were used as the main measure. Results: The results of this study showed that dysfunction and pain were significantly improved in all groups. Although dynamic postural stability with eyes closed was significantly improved only in the PWSTT group (p<.05), no significant difference was found in the other groups. Conclusion: The results of this study indicate that PWSTT improved balance, dysfunction and pain in the patients with CLBP. Thus, this intervention is necessary for patients with CLBP with decreased postural control.

• PNF and Movement
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• v.5 no.2
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• pp.37-46
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• 2007

Purpose : The purpose of this study was to examine the effects of combination of isotonic and rhythmic stabilization in proprioceptive neuromuscular facilitation on trunk stability and balance in elderly people with chronic low back pain. Subjects : Thirty-two elderly people ($73.78{\pm}8.49$ years of age) who had complaints of CLBP were randomly assigned to 2 groups: experimental group and control group. Methods : Subject trained with combination of isotonic and rhythmic stabilization in proprioceptive neuromuscular facilitation for 4weeks with aim of improving trunk stability and balance. Weight distribution, trunk muscle balance, static balance ability and dynamic balance ability were measured before, at the end of training. Results : Data were analyzed using two-way ANOVA. After the exercise programs, there were significant differences in the weight distribution, trunk muscle balance and dynamic balance ability between the experimental and control group. However there was no significant difference in the one leg stance test(p<.05). Conclusion : This study suggest that PNF programs may be appropriate for improving trunk stability and balance in elderly people with CLBP.

• Physical Therapy Korea
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• v.18 no.3
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• pp.49-58
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• 2011

The purpose of this study was to evaluate the effects of bridging stabilization exercise on balance ability and gait performance in elderly women. The subjects of this study were thirty-one elderly women over 65 years old in HongSung-Gun Senior Citizen Welfare Hall. The subjects were randomly assigned into one of three groups (trunk stabilization exercise on the mat, whole body vibration, and Swiss ball) and participated in each exercise program three times a week for 4 weeks. Each exercise began in the bridging position. The dynamic balance and gait were measured by limit of stability area using force plate, Berg Balance Scale (BBS), and Timed Up and Go Test (TUG). The results were as follows: 1) The limit of stability in three groups increased significantly in anterior-posterior and medial-lateral lean after 4-weeks intervention (p<.05). 2) There were no significant differences in the limit of stability among three groups after 4-weeks intervention (p>.05). 3) The BBS and TUG in three groups increased significantly after 4-weeks intervention (p<.05). 4) There were significant differences among three groups in BBS. Post-hoc test showed that Swiss ball exercise group was significantly higher than the mat and whole body vibration groups. 5) There were no significant differences TUG among three groups after 4-weeks intervention (p>.05). In conclusion, this study suggested that 4 weeks of the bridging stabilization exercises were effective on balance and gait in all three groups. Particularly Swiss ball exercise group showed higher improvement than two other exercise groups (mat, whole body vibration group).

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.6
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• pp.79-87
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• 2003

Application of combustion stabilization devices such as baffle and acoustic cavity to liquid propellant rocket engine is investigated to suppress high-frequency combustion instability, i.e., acoustic instability. First, these damping devices are designed based on linear damping theory. As a principal design parameter， damping factor is considered and calculated numerically in the chambers with/without these devices. Next, the unbaffled chambers with/without acoustic cavities are tested experimentally for several operating conditions. The unbaffled chamber shows the peculiar stability characteristics depending on the operating condition and it is found to have small dynamic stability margin. As a result, the acoustic cavity with the present design has little stabilization effect in this specific chamber. Finally， stability rating tests are conducted with the baffled chamber, where evident combustion stabilization is observed, which indicates sufficient damping effect.

• Journal of the Korean Society of Physical Medicine
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• v.19 no.2
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• pp.29-45
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• 2024

PURPOSE: This study aimed to compare the effects of pain level, lower back pain dysfunction level, psychosocial level, hip abductor strength (HAS), number of positive lumbar instability tests, and dynamic balance (DB) by applying lumbar stabilization exercises according to the presence or absence of gluteus medius muscle weakness in chronic lower back pain (CLBP) patients with lumbar instability. METHODS: Thirty-five CLBP patients with lumbar instability were divided into the gluteus medius weakness (n = 18) and gluteus medius non-weakened (n = 17) groups using the gluteus medius manual muscle test. Intervention applied conservative physical therapy and lumbar stabilization exercises to both groups that lasted three times a week for four weeks. To compare the intervention effects, the quadruple visual analog scale (QVAS), the Korean version of the Oswestry disability index (K-ODI), fear-avoidance beliefs questionnaire (FABQ), HAS, lumbar instability tests positive response counter (LIC), and DB were measured. RESULTS: Significant differences were shown for QVAS, K-ODI, FABQ, HAS, LIC, and DB for both groups pre- and post-intervention (p < .05). Compared to the gluteus medius weakness group, the gluteus medius non-weakened group showed a significant difference (p < .05) in the changes in QVAS, K-ODI, FABQ-W, FABQ-total, and HAS. CONCLUSION: In CLBP patients with lumbar instability, having gluteus medius weakness was less effective in improving lumbar stabilization exercise than gluteus medius non-weakness regarding pain level, lower back pain dysfunction level, psychosocial level excluding physical activity, and hip abductor strength. Therefore, additional gluteus medius strengthening exercises are necessary for patients with lumbar instability and gluteus medius muscle weakness.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.35 no.3
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• pp.1-12
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• 2003

The complexity of the papermaking system accelerates interactions between a large number of variables involved. The process operation, therefore, is subject to frequent perturbations by disturbance. Dynamic modelling is a useful tool for characterizing the transient behavior and selecting the best control strategies to reject disturbances. In this study we developed a dynamic simulation model of a fine paper production process, which consists of stock preparation, wire sections, white water circulations, and broke system. It focused on dynamic simulation in its role for developing control strategies and studying control loop dynamics related to filler loading for ash control. The results emphasized the importance of filler-loading position and length of control loop for rapid ash control and process stabilization.

• PNF and Movement
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• v.14 no.3
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• pp.237-244
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• 2016

Purpose: This case report examines the influence of proprioceptive neuromuscular facilitation (PNF) combined with a dynamic neuromuscular stabilization approach on balance in patients with cerebellar atrophy. Methods: The target subject of this case report was a 34-year-old woman who was informed of the purpose of this research and voluntarily agreed to participate in it. The case report conformed to research ethics based on the Helsinki Declaration. The target subject was confirmed to have cerebellar atrophy from an unknown cause in 2009 and was diagnosed with slight ataxia. At that time, she could carry out daily activities without physical therapy. On May 19, 2015, she suffered both a subdural hemorrhage (SDH) and subarachnoid hemorrhage (SAH) in a traffic accident. She was urgently moved to the emergency room and managed by nonsurgical treatment, and then, the cerebellar atrophy and ataxia gradually deteriorated. To evaluate the patient's balance capacity before and after intervention, the trunk impairment scale (TIS), trunk impairment scale (OLST) during eye-closing/opening, timed up and go test (TUG), and visual analogue scale (VAS) were conducted. The PNF intervention program was executed for 30 min, four times a week, for three weeks. Results: The TIS and OLST during eye-closing/opening were improved by as much as a point, by 8.15 s and 6.21 s, respectively, after applying the PNF program. TUG and VAS decreased by 1.33 s and 3 points, respectively, after intervention. According to the result, the OLST during eye-closing/opening and VAS improved remarkably in comparison with those before intervention. Conclusion: As the final result of the case report, PNF intervention combined with DNSA more effectively improved the static balance capacity, such as the OLST during eye-closing/opening and VAS, compared to the dynamic balance capacity. In addition, the intervention duration and period of the exercise program are recommended to be more than 1 h a day for four weeks considering the learning ability of a patient with cerebellar atrophy.