• Journal of Korea Water Resources Association
• /
• v.39 no.6 s.167
• /
• pp.503-510
• /
• 2006

Riverbank filtration is a natural process, using alluvial aquifers to remove contaminants and pathogens in river water for the production of drinking water. Back analysis which minimizes the objective function that is typically the sum of squares of the differences between the calculated and measured quantities is used for the estimation of aquifer parameters. In this study, transmissivity is back-analysed using the BFGS (Broyden-Fletcher-Goldfarb-Shanno) scheme for optimization. MOC is used to obtain calculated groundwater level. The developed inverse model was applied to Dae-san, Chang-won city where riverbank filtration is being undertaken. The model showed good convergence behavior for different groundwater conditions. The performance of the model was better than a widely-used commercial software package in terms of error between calculated and observed groundwater level.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2008.05a
• /
• pp.1300-1304
• /
• 2008

The fact that soil loss causing to increase muddy water and devastate an ecosystem has been appearing upon a hot social and environmental issues which should be solved. Soil losses are occurring in most agricultural areas with rainfall-induced runoff. It makes hydraulic structure unstable, causing environmental and economical problems because muddy water destroys ecosystem and causes intake water deterioration. One of three severe muddy water source areas in Soyanggang-dam watershed is Jawoon-ri region, located in Hongcheon county. In this area, many cash-crops are planted at illegally cultivated agricultural fields, which were virgin forest areas. The purpose of this study is to estimate soil loss with current land uses (including illegal cash-crop cultivation) and soil loss reduction with land use conversion from illegal cultivation back to forest. In this study, the Sediment Assessment Tool for Effective Erosion Control (SATEEC) ArcView GIS system was utilized to assess soil erosion. If the illegally cultivated agricultural areas are converted back to forest, it is expected to 17.42% reduction in soil loss. At the Jawoon-ri region, illegally cultivated agricultural areas located at over 30% and 15% slopes take 47.48 ha (30.83%) and 103.64 ha (67.29%) of illegally cultivated agricultural fields respectively. If all illegally cultivated agricultural fields are converted back to forest, it is expected that 17.41% of soil erosion and sediment reduction, 10.86% reduction with forest conversion from 30% sloping illegally agricultural fields, and 16.15% reduction with forest conversion from 15% sloping illegally agricultural fields. Therefore, illegally cultivated agricultural fields located at these sloping areas need to be first converted back to forest to maximize reductions in soil loss reduction and muddy water outflow from the Jawoon-ri regions.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.33 no.4
• /
• pp.319-322
• /
• 2011

Purpose: The purpose of this study was to examine the appropriate degree of set-back of the mandible by evaluating the rate of relapse after surgery. Methods: Among the patients who visited our hospital from January 2002 to January 2007 and who underwent orthognathic surgery, of the patients available for follow-up observation, the rate of relapse after surgery was investigated according to the set-back degree. The patients were divided into groups by the degree of set-back, and relapse was evaluated by the radiographs performed the day after surgery, 6 months after surgery, 1 year after surgery, 2 years after surgery and 3 years after surgery. Results: In cases that exceeded the limit of posterior movement of the mandible (13 mm) or that had the wrong position of the condyle, a greater tendency toward relapse was shown. Conclusion: Based on the results of this study, among the cases that required a large amount of posterior movement of the mandible, two jaw surgeries accompanied by bilateral sagittal split ramus osteotomy (BSSRO) and LeFort I osteotomy are recommended.

• Fire Science and Engineering
• /
• v.24 no.6
• /
• pp.153-159
• /
• 2010

In this study, we confirmed the fact that air egress velocity of pressure differential system installed at vestibule of smokeproof stairway in domestic high-rise building becomes back-flow to stair-lobby at upper vestibule. Rather it do not back-flow to the livingroom. when fire occur and the door opens to escape from fire zone. so we carry out actual and computational fluid dynamics measurement. In the case upward 45 gradient of supply damper's blade, The simulation results that air flow of upper vestible is steady but back-flow phenomenon occurred at the bottom. However, in the case of $4m^2$, direction of the flow was ideal to living room. If a vestibule’s area is smaller, it must be designed and built according to performance-based design.

• Journal of the Society of Disaster Information
• /
• v.16 no.1
• /
• pp.1-9
• /
• 2020

Purpose: In this study, the safety management method supplementing the field displacement prediction management technique was performed using the numerical analysis. Method: The analysis was performed using MIDAS GTS / NX program based on the finite element method (FEM). Approximating the displacement data and displacement trend as close as possible to the collapse site, the collapse prevention method was applied after estimating the cause of collapse. Result: The cause of the collapse was estimated by soil parametar, one of the results obtained by performing the Back-analysis. As a result, it was confirmed that the free length of the anchor was insufficient, and the free length of the anchor was changed by the collapse prevention method, and the displacement was significantly reduced. Conclusion: If Back-analysis technique is used in field management, estimating the cause of collapse and suggesting a reasonable collapse prevention measure will help to reduce collase.

• Physical Therapy Rehabilitation Science
• /
• v.9 no.3
• /
• pp.140-148
• /
• 2020

Objective: The purpose of this study was to examine the effectiveness of pelvic displacement when self-hamstring muscle stretches were applied to persons with low back pain. Design: Three-group pretest-posttest design. Methods: Forty persons with low back pain participated in this study. Pelvic tilt angle, hamstring flexibility, Quadruple Visual Analogue Scale (QVAS), Fear Avoidance Beliefs Questionnaire (FABQ), Korea version of the Oswestry Disability Index (KODI) and pelvic mobility were measured at pre-post. All participants were divided into either the pevic anterior tilt group (PAT group, n=12), pelvic midrange group (PMR group, n=18), or the pelvic posterior tilt group (PPT group, n=10). Self-stretching was performed using the pilates ring three times a week for a total of four weeks and the post-test was conducted and compared with the pre-test. Results: Hamstring flexibility, QVAS, KODI scores were significantly different compared to before the intervention (p<0.05). The changes in hamstring flexibility of the three groups were significantly different (p<0.05). Changes in KODI and FABQ results of the three groups were not significant. The pelvic posterior tilt range were significantly different in the PMR and PPT groups (p<0.05). The pelvic anterior tilt ranges showed significant differences after stretching in the PPT group (p<0.05). Conclusions: A large amount of change of hamstring flexibility, pelvic mobility of anterior and posterior tilt test in the PPT group was observed. Furthermore, therapists should consider pelvic displacement of the participant when applying intervention, which may, accordingly, have different effectiveness.

• Journal of Korean Medicine Rehabilitation
• /
• v.15 no.2
• /
• pp.17-30
• /
• 2005

Objectives : This study was designed to evaluate the changes of autonomic nervous system by heart rate variability(HRV) test on the musculoskeletal pain patients treated with acupuncture on the Back-su points and the unfixed points, and untreated healthy adults. Methods : This clinical study have been carried out with 64 cases of musculoskeletal pain patients and 26 healthy adults. 35 patients were treated with acupunctureon on the Back-su points(Group I) and 26 patients were treated on the Unfixed points(GroupII), and two groups were tested by HRV at pre and post acupuncture treatment. 26 healthy adults(GroupIII) were tested twice by HRV without any stimulation. Results : In Group I, VAS was decresased $5.83{\pm}1.62$ to $5.17{\pm}1.89$ significantly(p<0.05) after acupuncture treatment, and LF/HF ratio was decreased significantly(p<0.05) as compared with healthy control Group. In GroupII, SDNN & RMSSD were increased singnificantly(p<0.05) as compared with other Groups. in Group I & II, MHRT was decreased significantly(p<0.05) as compared with healthy control Group. Conclusions : These results suggest that acupuncture treatment on the Back-su points was able to reduce the pain, suppress the sympathetic activities and enhance the parasympathetic activities in musculoskeletal patients.

• Journal of the Korean Society of Physical Medicine
• /
• v.13 no.4
• /
• pp.113-121
• /
• 2018

PURPOSE: This study was conducted to identify a more effective intervention in sling and resistance exercise for chronic low back pain patients. METHODS: Seventy (70) subjects were randomly divided into the sling group (SG) and resistance exercise group (REG). Muscular activity of the internal oblique (IO), external oblique (EO), rectus abdominis (RA), and pelvic rotation angle during active straight leg raise (ASLR), a pressure pain threshold (PPT) and a visual analog scale (VAS) were measured. Sling and resistance exercises were conducted for 12 weeks. Intermediate measurements were taken after 8 weeks and final measurements were taken after 12 weeks. RESULTS: Both groups showed significantly decreased RA muscle activity and significantly increased IO muscle activity (p<.05). Additionally, EO muscle activity was significantly decreased in the REG, but significantly increased in the SG (p<.05), while the pelvic rotation angle and VAS were significantly decreased in the SG (p<.05). The pressure pain threshold was significantly increased in both groups (p<.05). CONCLUSION: Based on the results of this study, a 12-week intervention seems to be effective at improving back pain in both groups. However, a lower VAS was seen in the sling group after 8 weeks of intervention. Therefore, it is recommended that the sling be applied first when establishing a chronic back pain treatment program to shorten the treatment period and reduce the pain period.

• Journal of Digital Convergence
• /
• v.11 no.8
• /
• pp.243-250
• /
• 2013

The present study is to determine the effect of lumbosacral stabilization exercise program on back pain disorder and gait velocity of patients with chronic low back pain. The subject was extracted randomly from 34 patients with chronic low back pain and divided into 18 patients of experimental group and 16 patients of control group. Before the experiment, the Oswestry disability index examination and analysis of gait speed were performed. Then, a conventional interventional therapy of physiotherapy was performed with the experimental group along with the lumbosacral stabilization exercise while only the conventional interventional therapy was done to the control group. Both groups did the above treatment every 30 minutes, four times a week for four weeks. Then, post-examination was carried out followed by comparing the back pain disorder index and gait velocity before and after the experiment for the two groups. The back pain disorder index showed that both experimental and control groups had significant difference within the group (p>.01)(p>.05), With regard to the gait velocity, both experimental and control groups had a significant difference within the experimental group and between the groups (p>.001)(p>.05).

• Journal of the Korean Society of Physical Medicine
• /
• v.4 no.3
• /
• pp.133-140
• /
• 2009

Purpose：To investigate the effect of the home exercise program on pain, scoliosis, pelvic alignment of low back in chronic back pain patients, and suggest optimal method for home exercise program. Methods：I divided into two groups who has chronic back pain; one is control group who was given a treatment at the hospital only and the other is experimental group who did another exercise after treatment at the hospital, and there were 10 people in each group. The manual therapy were given to all the patients in each group after applying a stupe and an electric treatment, but the experimental group conducted another exercise program at homes. All the exercise programs were applied to patients 12 times for 4 weeks totally. Results：SPSS for win version 12 was used for statistic analysis and independent t-test was used to find changes between two groups. VAS scale was used to show changes in pain between each group. The grade of pain was decreased between pre&post test to -5.60 in control group and -4.80 in experimental group but there wasn't significant difference between each group. Cobb's degree was used to compare the changes of scoliosis in lumbar and it was improved in each group but there wasn't significant difference between each group. The measurement of pelvic misalignment was decreased between pre&post test to -1.00 in control group and -2.00 in experimental group but it wasn't enough to show significant difference between each group. Conclusion：As you read the results above, for a chronic low back pain patient, application of the manual therapy showed that it has effect on decrease of low back pain, improvement of scoliosis in lumbar and pelvic misalignment. However, the effect of home exercise treatment was not sure about improvements for chronic low back pain patient. So I think there should need further study about the effect of home exercise treatment except the treatments at hospital and the thorough education for the exercise of lumbar should be done before the study for the accurate experiment.