• Journal of the Korean Geotechnical Society
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• v.26 no.8
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• pp.49-58
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• 2010

In this study, in order to investigate the characteristics of secondary consolidation in the soft clay ground, oedometer tests were carried out in a normally consolidated condition, and the consolidation characteristics of the soft clay ground were examined by the Finite Difference Method (FDM) based on the Elasto-Viscous model proposed by Yoshikuni. The consolidation tests adjusted the consolidation load increment ratio(${\Delta}p/p_0$) to 1.0 for the four cases with initial consolidation pressures of 0.8, 1.6, 3.2, and 6.4 kgf/$cm^2$. The long-term consolidation tests were examined by the tests that changed the load increment ratio to clarify the effect of consolidation load increment. Although the numerical analysis was delayed in the primary consolidation process, from the result of the numerical analysis of the laboratory tests, the applicability of the Elasto-Viscous model was verified from the agreement of the secondary consolidation process. Based on the developing of model ground consist of general soft clay, influences of consoliation parameters on the consolidation characteristics were studied by the numerical analysis.

• Journal of the Korean Geotechnical Society
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• v.23 no.10
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• pp.97-107
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• 2007

Accurate evaluation of the slope stability by assuming failure block as the entire slope is considered to be apposite for the small scale slope, whereas it is not the case for the large scale slope. Hence, appropriate estimation of a failure block size is required since the safety factor and the joint strength parameters are the function of the failure block size. In this paper, the size of failure block was investigated by generating 3-dimensional rock joint system based on statistical data of joints obtained from research slope, such as joint orientation, spacing and 3-dimensional joint intensity. The result indicates that 33 potential failure blocks exist in research slope, as large as 1.4 meters at least and 38.7 meters at most, and average block height is 15.2 meters. In addition, the data obtained from 3 dimensional joint system were directly applicable to the probability analysis and 2 and 3 dimensional discontinuity analysis.

• Journal of Korean Foot and Ankle Society
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• v.26 no.1
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• pp.40-47
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• 2022

Purpose: The modified Broström repair (BR) technique has yielded good outcomes in patients with chronic ankle instability. This study compared clinical and radiological outcomes between two groups of patients who underwent modified BR or lateral ligament augmentation using suture tapes (ST). Materials and Methods: Seventy-seven patients (ST group [n=47], BR group [n=30]; body mass index <26.61 kg/m²; mean age, 30.7±11.0 years [range, 17~39 years]; mean follow-up, 34.0±12.0 months [range, 24~59 months]) were retrospectively reviewed between January 2014 and July 2017. The Foot and Ankle Outcome Score (FAOS), American Orthopedic Foot and Ankle Score (AOFAS), Foot and Ankle Ability Measure (FAAM), visual analogue scale (VAS) score, and Sefton grading system were used for clinical assessment. The talar tilt angle and anterior talar translation were measured using the Telos stress device (Telos GmbH, Marburg, Germany) at 150 N for radiological evaluation. Results: FAOS, AOFAS, FAAM, and VAS scores improved in both groups at final follow-up (ST, 91.1±5.2, 93±2, 88.1±4.5, 1.5±0.7 vs. BR, 91.3±5.4, 93±3, 83.3±4.8, 1.2±0.7, respectively; p=0.854, 0.971, <0.001, 0.04, respectively). According to the FAOS, mean sports activity scores for the ST and BR groups at the final follow-up were 90.3±3.2 and 76.6±4.2, respectively, reflecting superior outcomes in the ST group (p<0.001). Sefton grading revealed satisfactory functional outcomes (ST, 91.5% vs. BR, 90.0%). There was significant improvement in the talar tilt angle and anterior talar translation in both the ST and BR groups (7.6°±1.2°, 10.5±1.8 mm vs. 4.9°±1.1°, 7.9±1.5 mm, respectively; p<0.001). Conclusion: The ST group demonstrated comparable clinical but better improvement in mechanical stability and FAOS sports scores than the BR group.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.487-487
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• 2021

탁수는 유기물 또는 무기물이 유입되면서 빛의 투과성이 낮아진 수체를 의미한다. 탁수가 발생하게 되면 어류의 폐사, 정수처리 비용의 증가 및 경관의 변화로 인한 피해가 발생하게 된다. 국내에서는 홍수기 또는 태풍 시 유역의 토사가 저수지 상류에서 유입하여 호내의 탁수를 발생시키는 경우가 있는데, 특히 낙동강 유역의 임하호에서 빈번하게 고탁수가 발생하여 왔다. 본 연구에서는 임하호에서 탁수 발생 시 신속 배제를 위한 수치적인 예측 시스템을 소개하고자 한다. 저수지 탁수관리의 기본개념은 용수공급능력을 고려한 고탁수의 신속한 배제이다. 이는 선제적 의사결정을 요구하므로, 지류에서 탁수가 발생한 즉시 향후 상황에 대한 예측이 필요하다. 이러한 예측을 위해 유역관리처는 3단계의 수치해석을 수행한다. 첫 번째는 유역 상류에서 탁수가 감지되었을 때, 호 내 탁수의 분포를 예측하는 것이다. 수심 및 수평방향의 탁수 분포에 대한 상세한 결과가 도출되어야 하기에, 3차원 수치해석 프로그램인 AEM3D를 이용한다. 이때, 과거 고탁수 유입에 대한 자료를 기반으로 산정된 매개변수가 적용된다. 두 번째는 예측된 호내 분포를 초기조건으로 댐 방류량 및 취수탑 위치(선택배제)에 따른 탁수 배제 수치해석을 수행하게 된다. 다양하고 많은 case에 대한 신속한 모의 및 3달 이상의 장기간 예측을 요구하므로, 2차원 수치모델인 CE-QUAL-W2를 활용한다. 이 단계에서 수자원의 안정적 공급이 가능한 범위 내에서 효과적인 탁수 배제 방류 방법 등이 결정되며, 방류 탁도가 예측된다. 세 번째 단계는 방류탁도를 경계조건으로 하여 하류 하천(반변천~내성천 합류 전)의 탁도를 예측하는 것이다. 하천의 탁도 예측은 국내뿐만 아니라 국외에서도 그 사례를 찾아보기가 쉽지 않은데, 이는 중소형의 지류에 대한 입력자료가 충분하지 않고 불확실성이 높기 때문이다. 이에 과거 10여 년의 data를 이용한 회귀분석을 통해 탁수 발생물질(SS)-부유사-유량과의 관계를 도출하고, 2차원 하천모델(EFDC)을 이용하여 수심 평균 탁도를 예측하게 된다. 이러한 세 단계의 예측은 탁수가 호내로 유입됨에 따라 반복되고, 점차 예측 정확도가 향상되게 된다. 세 단계의 과정을 통한 임하호 탁수의 조기 배제는 현재 적지 않은 효과를 거두고 있다고 판단된다. 그러나 탁수를 발생시키는 현탁물질의 종류는 매번 일정하지 않기 때문에, 이러한 예측 시스템에 정확도에 영향을 줄 수 있으므로, 여러 상황을 고려한 딥러닝을 도입하여 탁수 물질에 대한 정보를 예측한다면 보다 합리적인 의사결정 지원 도구가 될 수 있을 것이다.

• 한국체육학회지인문사회과학편
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• v.55 no.4
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• pp.507-516
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• 2016

The purpose of this study is to identify the effects of PPARβ/δ over-expression on PGC-1α mRNA and protein stability after single bout of swimming exercise in mice skeletal muscle. Empty vector (EV) or PPARβ/δ was over-expressed in tibialis anterior(TA) using electroporation(EPO) technique to compare with non-treatment muscle(control; Con). TA muscles were dissected at 0h, 24h or 54h after termination of exercise. PGC-1α mRNA in Con, EV and PPARβ/δ over-expressed muscles were increased 6.8 fold (p<.001), 6.2 fold(p<.001) and 7.1 fold(p<.001), respectively, than sedentary(Sed) group at 0h after exercise and then reverted to Sed group levels at 24h and 54h after termination of exercise. PGC-1α and PGC-1α ubiquitination in EV treated muscles were increased 2.2 fold and 1.74 fold, respectively, than Sed group at 24h after termination of exercise, and then reverted to Sed group levels at 54h after termination of exercise. PGC-1α in PPARβ/δ over-expressed muscles at 24h and 54h after termination of exercise were increased 2.5 fold and 2.2 fold, respectively, than Sed group, but PGC-1α ubiquitination was not increased at 24h and 54h after termination of exercise. Our results indicate that PPARβ/δ over-expression does not increase PGC-1α mRNA stability, but increase PGC-1α protein stability through post-translation mechanism after termination of exercise.

• Ecology and Resilient Infrastructure
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• v.10 no.4
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• pp.171-183
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• 2023

Estuarine wetlands, which form a distinctive brackish water zone, serve as important habitats for organisms that have adapted to and thrive in this environment. Nonetheless, excessive development and utilization result in artificial disruptions that alter the distinctive functions and attributes of estuarine wetlands. To collect the basic data for the conservation of estuarine wetlands with excellent ecosystems, we investigated the vegetation distribution characteristics and biota status of the Taehwagang River Estuarine Wetland. Data from vegetation surveys have shown that 25 plant communities of six physiognomic vegetation types, including willow vegetation, lotic and lentic herbaceous vegetation, floating/submerged vegetation. In the upper reaches, where topographical diversity was high, various types of wetland vegetation were distributed. In terms of biodiversity, a total of 696 species, including 7 endangered wildlife species, were identified. Due to good ecological connectivity, tidal rivers are formed, brackish water species including various functional groups are distributed around this section. The inhabitation of various water birds, such as diving and dabbler ducks, were confirmed according to the aquatic environment of each river section. The collection of ecological information of the Taehwagang River Estuarine Wetland can be used as a framework for establishing the basis for conservation and management of the estuarine ecosystem and support policy establishment.

• The Journal of Engineering Geology
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• v.33 no.4
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• pp.611-626
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• 2023

Overseas examples of the characterization stage of site selection proposed by the International Atomic Energy Agency were reviewed to highlight the factors necessary for consideration in the deep disposal of high-level radioactive waste. Studies in Sweden, Finland, the USA, and Canada were considered. Site investigations in Sweden and Finland commonly covered the fields of geology, hydrogeology, and hydrogeochemistry using similar field investigation techniques. The USA considered survey groups and factors under pre- and post-lockdown guidelines, as well as those for desaturated and saturated surveys. involving geophysical, hydrological, hydrogeological, hydrogeochemical, mechanical/physical, and thermal-characterization investigations. Canada provided a list of investigative methods for both preliminary and detailed site assessments including geological, physical, boring, hydrological, laboratory testing, and chemical analysis studies. Results of this study should elucidate site-selection investigation factors and survey methods applicable to Korea.

• Journal of the Korean Society of Radiology
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• v.17 no.7
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• pp.1197-1205
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• 2023

In this study, the spectrum due to radioactivity contained sand samples from famous beaches in the Yeongnam region was measured. The sand samples were from eight famous beaches in Yeongnam region and were placed into a high-purity germanium detector (HPGe) using with an electric field, which is a semiconductor detector and subjected to a precision analysis of the gamma-rays emitted from the radionuclides in the sand by using a multichannel analyzer (MCA). To measure the concentration of the radionuclides, we obtained a spectrum by analyzing the gamma-rays emitted from the radionuclides for a measurement time of 8,000 seconds. As a result of analyzing the spectrum table, Tl-208 had the highest radioactivity at all eight beaches: A, B, C, D, E, F, G, and H. In conclusion, radionuclides detected in sand samples from beaches in the Yeongnam region are natural radionuclides, but they can affect the inside of the human body. Therefore, there is a need for continuous investigation.

• Journal of the Korean institute of surface engineering
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• v.57 no.1
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• pp.38-48
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• 2024

We fabricated In₂O₃ zig-zag nanocolumns(ZZNCs) by oblique angle deposition method based on e-beam evaporator for highly sensitive and selective CH₃COCH₃ sensor. Our results indicate that as the ZZNCs layer stacks, the gas response also increases. In comparison to thin films, ZZNCs at 5 layer show a 117-fold enhancement in gas response and a rapid response time (~2 s). When measured with various gases, it showed a high selectivity towards acetone. Under conditions of 80% R.H., exposure to CH₃COCH₃ gas theoretically indicated a detection limit of 1.2 part-per-billion(ppb). These results suggest the potential of In₂O₃ ZZNCs as a breath analyzer for the diagnosis of diabetes.

• Journal of Korean Society of Forest Science
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• v.113 no.1
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• pp.131-142
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• 2024

The purpose of this study was to estimate the optimal stand density criteria for each growth stage of Chamaecyparis obtusa (Siebold & Zucc.) Endl. to achieve the timber production goal for cypress forests and develop an optimal silvicultural system for forest thinning. A relative yield index (Ry) value of 0.75, presented as a stand density management criterion index, was estimated by analyzing the relationship characteristics between the composition ratio and stand density of slender trees from 216 sample plots of the recruited cypress forests. The analysis of the feasibility of achieving each production target in the existing silvicultural system for C. obtusa revealed that the growth rate according to the parameters of forest land productivity, such as site index and thinning intensity according to the increase in age, was not properly reflected. In the thinning system for each timber production target analyzed in this study, 353 high-quality large hardwoods from 498.1 m³/ha, 703 high-quality medium hardwoods from 376.2 m³/ha, and 1,758 small-diameter hardwoods from 249.5 m³/ha could be harvested. Although the silvicultural system prepared on the basis of the results of this study cannot be uniformly applied according to various management goals, this study is meaningful in that it presents empirical reference standards based on the stand density management diagram that reflects the growth characteristics of cypress forests in South Korea.