• Composites Research
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• v.30 no.4
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• pp.229-234
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• 2017

Generally, joints are the weakest part in the composite structures. Composite joints can be classified into adhesive joints and mechanical joints, and mechanical joints are mainly used in areas less sensitive to environmental conditions. In this paper, the failure loads of composite mechanical joints with five different stacking angles are tested and predicted. Finite element analysis of mechanical joints were performed and failure loads were predicted by the FAI(Failure Area Index) method using Tsai-Wu and Yamada-Sun failure criteria, and the predicted failure loads were compared with experimental results. From the experiment and analysis, the failure loads of the mechanical joints were decreased as the ratio of 0 degree layer was low and they could be predicted within 13.03% using the FAI method and Yamada-Sun failure criteria.

• Journal of Korean Society on Water Environment
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• v.31 no.3
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• pp.319-327
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• 2015

The present study was carried out to develop biological criteria for aquatic ecosystem health assessment using composition and diversity of collected species. The sampling sites were a total of 67 sites in the Han River (29 sites) and the Nakdong River (38 sites), May and September 2012. During the survey period fish were collected totally 93 species. In each water system, 73 and 61 species were collected in the Han River and the Nakdong River respectively. The current composition of fish species between the Han River and Nakdong River showed similar pattern. The dominant species was Zacco platypus of the Han River, and the Nakdong River was Opsariichthys uncirostris. In particular, ecological characteristics of O. uncirostris frequently appeared in general polluted waters. In conclusion, in the Nakdong River, average value of FAI (Fish Assessment Index) was averaged 41.3, indicating a "poor condition", and the Han River was 53.1, indicating a "poor condition". The aquatic health of the Nakdong River assessed based on FAI was considered to be worse than that of the Han River.

• PNF and Movement
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• v.18 no.2
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• pp.183-194
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• 2020

Purpose: Functional ankle instability (FAI) causes tension in the joints, ligaments, and tendons, and the impact on visual and vestibular organs leads to imbalance. This study compared the effects of a traditional balance training program to virtual reality training to improve FAI. Methods: Twenty-four participants with FAI (CAIT score < 24) were assigned to a virtual reality training group (n = 13) and a traditional balance training group (n = 11). Both groups pursued their respective training program for four weeks. After a ten-minute warm-up, participants completed a 30-minute training session, three times per week. The traditional balance training group underwent static and dynamic training using a balance board and a stability trainer pad while the virtual reality group underwent balance training using a virtual reality program. Biorescue was used to measure changes in the speed and length of center of pressure (COP) for single-leg stance pre- and post-training. Results: The speed and length of COP improved significantly in both groups after training as compared to before (p < 0.05). However, there were no significant differences in these outcomes between the virtual reality training group and the traditional balance training group (p>0.05). Conclusion: The study findings confirm the effectiveness of both virtual reality training and traditional balance training in reducing ankle instability, with no difference in treatment effects.

• Journal of Astronomy and Space Sciences
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• v.38 no.2
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• pp.135-143
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• 2021

We report, for the first time, the afternoon (i.e., from noon to sunset time) observations of the northern mid-latitude E-region field-aligned irregularities (FAIs) made by the very high frequency (VHF) coherent backscatter radar operated continuously since 29 December 2009 at Daejeon (36.18°N, 127.14°E, 26.7°N dip latitude) in South Korea. We present the statistical characteristics of the mid-latitude afternoon E-region FAIs based on the continuous radar observations. Echo signal-to-noise ratio (SNR) of the afternoon E-region FAIs is found to be as high as 35 dB, mostly occurring around 100-135 km altitudes. Most spectral widths of the afternoon echoes are close to zero, indicating that the irregularities during the afternoon time are not related to turbulent plasma motions. The occurrence of afternoon E-regional FAI is observed with significant seasonal variation, with a maximum in summer and a minimum in winter. Furthermore, to investigate the afternoon E-region FAIs-Sporadic E (E_s) relationship, the FAIs have also been compared with E_s parameters based on observations made from an ionosonde located at Icheon (37.14°N, 127.54°E, 27.7°N dip latitude), which is 100 km north of Daejeon. The virtual height of E_s (h'E_s) is mainly in the height range of 105 km to 110 km, which is 5 km to 10 km greater than the bottom of the FAI. There is no relationship between the FAI SNR and the highest frequencies (f_tE_s) (or blanket frequencies (f_bE_s)). SNR of FAIs, however, is found to be related well with (f_tE_s-f_bE_s).

• Journal of The Korean Society of Integrative Medicine
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• v.10 no.1
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• pp.73-79
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• 2022

Purpose : Kinesio taping applied to the ankle varies, and if the overall ankle is taped as much as possible, several effects, including balance, can be expected, but clinically the cost reduction for intervention is very important. Therefore, this study attempted to find out the optimal way to the effect and cost of kinesio taping on ankle dynamic balance. Methods : The subject of this study was 24 university students in their 20s (male: 13, female: 11), who received sufficient explanation of the purpose and method of the study. The Cumberland ankle instability tool (CAIT) questionnaire was used for the degree of ankle instability of the study subjects. If the subject's CAIT score was 28 points or more, it was classified as a stable ankle, and if the score was 24 points or less, it was classified as functional ankle instability (FAI). In this study, Biodex Balance System^® measurement equipment was used to calculate the dynamic balance of study participants. The application of kinesio taping was performed by one physical therapist to attach in the same way, and a method of wrapping the ankle joint was applied in the eight-shaped bandage. Results : The results are as follows in before and after taping of the stable ankle and FAI group. There was no significant difference in the overall, anterior-posterior, and medial-lateral stability index. The comparison is as follows between groups for the differences (post-pre value) in before and after the application of kinesio taping. There were no significant differences between groups in all the overall, anterior-posterior, and medial-lateral stability index. Conclusion : In this study, no significant difference in kinesio taping was found in the dynamic balance of stable ankle and FAI (overall, anterior-posterior, and medial-lateral). It is necessary to continue to study ways to find the maximum effect while minimally attaching them to the application method of ankle kinesio taping.

• Journal of Korea Water Resources Association
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• v.51 no.10
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• pp.863-874
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• 2018

The purpose of this study is to evaluate the future climate change impact on stream aquatic ecology health of Han River watershed ($34,148km^2$) using SWAT (Soil and Water Assessment Tool) and random forest. The 8 years (2008~2015) spring (April to June) Aquatic ecology Health Indices (AHI) such as Trophic Diatom Index (TDI), Benthic Macroinvertebrate Index (BMI) and Fish Assessment Index (FAI) scored (0~100) and graded (A~E) by NIER (National Institute of Environmental Research) were used. The 8 years NIER indices with the water quality (T-N, $NH_4$, $NO_3$, T-P, $PO_4$) showed that the deviation of AHI score is large when the concentration of water quality is low, and AHI score had negative correlation when the concentration is high. By using random forest, one of the Machine Learning techniques for classification analysis, the classification results for the 3 indices grade showed that all of precision, recall, and f1-score were above 0.81. The future SWAT hydrology and water quality results under HadGEM3-RA RCP 4.5 and 8.5 scenarios of Korea Meteorological Administration (KMA) showed that the future nitrogen-related water quality in watershed average increased up to 43.2% by the baseflow increase effect and the phosphorus-related water quality decreased up to 18.9% by the surface runoff decrease effect. The future FAI and BMI showed a little better Index grade while the future TDI showed a little worse index grade. We can infer that the future TDI is more sensitive to nitrogen-related water quality and the future FAI and BMI are responded to phosphorus-related water quality.

• Korean Journal of Applied Biomechanics
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• v.20 no.4
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• pp.395-406
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• 2010

The purpose of this study was to analyze the changes in kinematic and kinetic parameters of lower extremity joint according to rehabilitation period. Fourteen collegiate male athletes(age: $22.1{\pm}1.35$ years, height: $182.46{\pm}9.45cm$, weight: $88.63{\pm}9.25kg$) and fourteen collegiate athletes on functional ankle instability(age: $21.5{\pm}1.35$ years, height: $184.45{\pm}9.42cm$, weight: $92.85{\pm}10.85kg$) with the right leg as dominant were chosen. The subjects performed drop landing. The date were collected by using VICON with 8 camera to analyze kinematic variables and force platform to analyze kinetic variables. There are two approaches of this study, one is to compare between groups, the other is to find changes of lower extremity joint after rehabilitation. In comparison to the control group, FAI group showed more increased PF & Inversion at IC and decreased full ROM when drop landing. Regarding the peak force and loading rate, it resulted in higher PVGRF and loading. FAI group used more increased knee and hip ROM because of decreased ankle ROM to absorb the shock. And it used sagittal movement to stabilize. In terms of rehabilitation period, FAI group showed that landing patterns were changed and it increased total ankle excursion and used all lower extremity joint close to normal ankle. Regarding the peak force and loading rate, FAI group decreased PVGRF and loading rate. and also showed shock absorption using increased ankle movement. And COP variable showed that proprioception training increased stability during 8 weeks. The results of this study suggest that 8 weeks rehabilitation period is worthwhile to be considered as a way to improve neuromuscular control and to prevent sports injuries.

• Journal of International Academy of Physical Therapy Research
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• v.6 no.2
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• pp.891-895
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• 2015

We investigated the effects of a Virtual reality(VR) program on the proprioception and instability of functional ankle instability(FAI) patients. Among the 20s old individuals who lived in Republic of Korea; 20 people were selected through a public participation process. The 20 participants were then randomly divided into two groups, one of strength exercise(n=10) and one of balance exercise(n=10). Of the patients who had experienced an ankle sprain in the past and currently felt ankle instability, those who recorded 24 points or less on the Cumberland ankle instability tool(CAIT) were determined to have FAI. We selected the strength exercise and balance exercise in the Nintendo Wii Fit Plus as a VR program. The subjects used the program on the Wii Balance Board three times per week for 20 minutes and total 10-minute warm-up and down for four weeks. Proprioception and CAIT of the balance exercise group were improved significantly after the exercise compared to before the exercise(p<.05). Authors recommend that the balance exercise in the VR program be used as an aid for physical therapeutic intervention.

• The Journal of Korean Physical Therapy
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• v.33 no.1
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• pp.28-33
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• 2021

Purpose: This study examined the effects of heel raise exercises combined with neuromuscular electrical stimulation (NMES) on the muscle strength and postural control ability of subjects with functional ankle instability (FAI). Methods: Twenty-two subjects with FAI participated in this study. They were assigned randomly to two groups: 11 each in the NMES and the sham-NMES groups. Heel raise exercise was applied, and NMES electrodes were attached to the peroneus longus muscles. The NMES group applied NMES during the heel raise exercise. NMES was applied for 20 minutes during the heel raise exercise. The heel raise exercise was performed four times a week for five weeks. The muscle strength and balance error scoring system (BESS) were measured before and after the intervention. Results: A comparison of before and after the intervention within the groups revealed improved muscle strength in the NMES and Sham-NMES groups, but the BESS was improved under all conditions only in the NMES group. The Sham-NMES group showed no improvement in the unstable support surface. Furthermore, when comparing the amount of change before and after the intervention between the groups, there were significant differences in the total score and unstable support in the BESS and muscle strength. Conclusion: NMES had a positive effect on the functional activities of the functional ankle instability subjects, such as balancing on an unstable support surface during postural control and increasing muscle strength.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.445-445
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• 2021

대구시민의 삶의 질 향상에 크게 기여하는 신천은 홍수, 친수 및 하천환경 관리에 대한 필요성이 증가되는 상황에서 신천 복원을 위하여 하천횡단구조물 및 생태조사가 필요한 실정이다. 신천 내에 위치하고 있는 14개의 하천횡단구조물은 신천의 흐름을 가로막고 있어 수질악화 및 생물이동을 저해하고 있으며, 집중호우 등으로 인하여 구조물 주변에 대한 하천관리가 어려운 것이 현실이다. 특히 신천은 인구가 밀집해 있는 도심을 관통하는 하천으로 친수공간, 홍수 및 하천환경 관리에 대한 필요성이 증가하고 있다. 본 연구에서는 신천의 수질과 어류의 생태성의 상관관계를 확인하고 횡단구조물에 대한 해결방안을 제시하고자 한다. 현지조사 결과 총 3목 6과 10종의 어류가 관찰되었으며, 법정보호종인 멸종위기 야생생물 및 천연기념물은 관찰되지 않았으나, 고유종으로 긴몰개와 참갈겨니, 꺽지, 동사리 4종이 출현하였으며, 환경부 지정 생태계교란 생물 블루길 1종이 관찰되었다. 이러한 결과를 바탕으로 어류생물지수(FAI)를 검토하였을 때, 하류지역으로 갈수록 E등급으로 매우 나쁨의 환경상태를 나타내었다. 이는 상류에서 하류로 갈수록 비정상개체수가 증가하고 하상의 단순화 및 유기물의 축적으로 출현 종수의 감소에 따른 결과로 판단된다. 이러한 결과를 바탕으로 신천의 평균 FAI 지수는 14.71점으로 E등급의 매우 나쁨의 환경상태를 나타내는 것으로 분석되었다.