• Geomechanics and Engineering
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• 제29권3호
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• pp.321-329
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• 2022

Tunnel site where high water pressure is applied, such as subsea tunnel, generally selects the shield TBM (Tunnel Boring Machine) to maintain the tunnel excavation face. The shield TBM has cutters installed, and the cutters wear out during the process of excavation, so it should be checked and replaced regularly. This is called CHI (Cutterhead Intervention). The conventional CHI under high water pressure is very disadvantageous in terms of safety and economics because humans perform work in response to high water pressure and huge water inflow in the chamber. To overcome this disadvantage, this study proposes a new method to dramatically reduce water pressure and water ingress by injecting an appropriate grout solution into the front of the tunnel face through the shield TBM chamber, called New Face Grouting Method (NFGM). The tunnel model tests were performed to determine the characteristics, injection volume, and curing time of grout solution to be applied to the NFGM. Model test apparatus was composed of a pressure soil tank, a model shield TBM, a grout tank, and an air compressor to measure the amount of water inflow into the chamber. The model tests were conducted by changing the injection amount of the grout solution, the curing time after the grout injection, and the water/cement ratio of grout solution. From an economic point of view, the results showed that the injection volume of 1.0 L, curing time of 6 hours, and water/cement ratio of the grout solution between 1.5 and 2.0 are the most economical. It can be concluded that this study has presented a method to economically perform the CHI under the high water pressure.

• 산업경영시스템학회지
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• 제45권4호
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• pp.233-239
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• 2022

The injection molding process is a process in which thermoplastic resin is heated and made into a fluid state, injected under pressure into the cavity of a mold, and then cooled in the mold to produce a product identical to the shape of the cavity of the mold. It is a process that enables mass production and complex shapes, and various factors such as resin temperature, mold temperature, injection speed, and pressure affect product quality. In the data collected at the manufacturing site, there is a lot of data related to good products, but there is little data related to defective products, resulting in serious data imbalance. In order to efficiently solve this data imbalance, undersampling, oversampling, and composite sampling are usally applied. In this study, oversampling techniques such as random oversampling (ROS), minority class oversampling (SMOTE), ADASYN(Adaptive Synthetic Sampling), etc., which amplify data of the minority class by the majority class, and complex sampling using both undersampling and oversampling, are applied. For composite sampling, SMOTE+ENN and SMOTE+Tomek were used. Artificial neural network techniques is used to predict product quality. Especially, MLP and RNN are applied as artificial neural network techniques, and optimization of various parameters for MLP and RNN is required. In this study, we proposed an SA technique that optimizes the choice of the sampling method, the ratio of minority classes for sampling method, the batch size and the number of hidden layer units for parameters of MLP and RNN. The existing sampling methods and the proposed SA method were compared using accuracy, precision, recall, and F1 Score to prove the superiority of the proposed method.

• Journal of Dental Anesthesia and Pain Medicine
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• 제23권3호
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• pp.135-141
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• 2023

Background: The limited studies on the effect of buffering on the clinical efficacy of articaine have reported controversial results. The purpose of this study was to clinically compare the pain of injection, anesthetic success, onset, and duration of pulpal anesthesia of buffered 4% articaine with epinephrine 1:100000 versus a non-buffered 4% articaine with epinephrine 1:100000 formulation for buccal infiltration of the mandibular first molar. Methods: Sixty-three volunteers were enrolled in the study. All volunteers received two injections consisting of a single mandibular first molar buccal infiltration with 1.8 ml of 4% articaine with epinephrine 1:100000 and 1.8 ml of 4% articaine with epinephrine 1:100000 buffered with 8.4% sodium bicarbonate. The infiltrations were applied in two separate appointments spaced at least one week apart. After injection of the anesthetic solution at the examined site, the first molar was pulp-tested every 2 min for the next 60 min. Results: Successful pulpal anesthesia was recorded in 69.8% of cases using non-buffered articaine solution and 76.2% of cases using buffered articaine solution, with no significant difference between the formulations (P = 0.219). The mean time of anesthesia onset for the volunteers with successful anesthetic outcome in both formulations (n = 43) was 6.6 ± 1.6 min for the non-buffered articaine solution and 4.5 ± 1.6 min for the buffered solution, which differed significantly (P = 0.001). In the same volunteers, the mean duration of pulpal anesthesia was 28.4 ± 7.1 min for non-buffered articaine solution and 30.2 ± 8.5 min for buffered articaine solution, with no significant difference between the formulations (P = 0.231). Considering the pain of injection, regardless of the anesthetic success, the mean values of VAS were 11.3 ± 8.2 mm for the non-buffered articaine solution and 7.8 ±6.5 mm for the buffered articaine solution, which differed significantly (P = 0.001 < 0.05). Conclusion: According to the present study, 4% articaine with epinephrine can benefit from buffering and provide better anesthetic behavior, with improved onset and less pain during injection.

• 한국측량학회지
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• 제33권5호
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• pp.427-436
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• 2015

본 연구는 건기에 1일 50ton 규모의 지하수 양수를 목적으로 하는 소규모 인공함양(Artificial Recharge) 지하저수지 설치를 위한 적지선정 기법을 모색한다. 먼저 수리모델 실험결과 다양한 인자에 부응하는 적지 후보지 형상을 정의하고, 주입과 양수모델링 실험을 수행하여 적합한 양수효율을 산정하였다. 다음으로는 최적 후보지 선정을 위하여 각종 지형공간정보를 처리하여 GIS(Geographic Information System) DB를 구축하였다. 구체적으로 설명하면, 5m 격자의 DEM(Digital Elevation Model)으로부터 유역분할 영상을 생성하여 적지의 최소단위로 정의하며 경사도를 이용하여 일정기간의 대수층 저류 기간을 확보하기 위한 적정 수두구배를 결정한다. 최종적으로 유역 분할 영상과 경사도, 정사영상 및 DEM 자료 등을 종합 이용하여 최적 형상에 준하는 영역을 인공함양의 최종 후보지로 선정한다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제16권6호
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• pp.66-78
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• 2011

It is getting difficult to manage water resources in South Korea because more than half of annual precipitation is concentrated in the summer season and its intensity is increasing due to global warming and climate change. Artificial recharge schemes such as well recharge of surface water and roof-top rainwater harvesting can be a useful method to manage water resources in Korea. In this study, potential artificial recharge site is evaluated using geographic information system with hydrogeological and social factors. The hydrogeological factors include annual precipitation, geological classification based on geological map, specific capacity and depth to water level of national groundwater monitoring wells. These factors were selected to evaluate potential artificial recharge site because annual precipitation is closely related to source water availability for artificial recharge, geological features and specific capacity are related to injection capacity and depth to water is related to storage capacity of the subsurface medium. In addition to those hydrogeological factors, social aspect was taken into consideration by selecting the areas that is not serviced by national water works and have been suffered from drought. These factors are graded into five rates and integrated together in the GIS system resulting in spatial distribution of artificial recharge potential. Cheongsong, Yeongdeok in Gyeongsangbuk-do and Hadong in Gyeongsangnam-do, and Suncheon in Jeollanam-do were proven as favorable areas for applying artificial recharge schemes. Although the potential map for artificial recharge in South Korea developed in this study need to be improved by using other scientific factors such as evaporation and topographical features, and other social factors such as water-curtain cultivation area, hot spring resorts and industrial area where groundwater level is severely lowered, it can be used in a rough site-selection, preliminary and/or feasibility study for artificial recharge.

• Archives of Plastic Surgery
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• 제37권3호
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• pp.233-238
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• 2010

Purpose: As the use of soft tissue fillers becomes more popular, complications such as foreign body granuloma (FBG) are increasing. We report 120 cases of facial FBG and review the available literatures. Methods: 120 patients of facial FBG in our clinic from Mar. 2003 to Feb. 2008 were complied and analyzed. A retrospective chart review was done and patient satisfaction was evaluated with a questionnaire using 5 score scale. Patients with severe inflammation sign or bizarre deformity underwent surgical excision and those with minimal symptoms or a history of hyaluronic acid injection received injection therapy using hyaluronidase. Results: 100 females and 20 males were observed. The average age was 43.7 years (from 16 to 74). 84 patients received surgical therapy and 36, injection therapy. Deformity of facial contour, foreign body sensation and inflammation sign were the three main chief complaints. 84 patients did not know what the injection materials were. The known materials are as follows: collagen, hyaluronic acid, silicone oil, paraffin. 92 cases were performed by unlicensed practitioners, 29 by physicians. Anatomical site most frequently affected by the foreign body granuloma was the cheek (25.8%), followed by forehead (19.2%), lips (15.8%), nose (9.2%), mentum (8.3%), eyelid and eyebrow (4.3%) and temple (0.8%). In 21 patients (17.5%), FBGs were found on multiple sites. Patients with inflammation sign got the highest satisfaction ($3.19{\pm}0.73$) (p=0.001) among 3 chief complaints. And patient satisfaction was statistically higher in surgical therapy group ($3.43{\pm}0.72$) than in injection therapy group ($2.97{\pm}0.88$) (p=0.003). Conclusion: We suggest that it may be beneficial to tailor the type of treatment for FBG relying on wound state and patient's chief complaints. In surgical therapy, resolute approach is necessary to correct facial deformity definitely and to minimize inflammation. Injection therapy could be another option for those with minimal symptoms or a history of hyaluronic acid injection. To prevent foreign body granuloma, not only plastic surgeons but also other physicians should inject soft tissue fillers with great caution and we should warn the public of disastrous consequences associated with illegal medical practice.

• 한국가스학회지
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• 제25권4호
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• pp.36-42
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• 2021

쓰레기 매립지에 발생하는 매립지가스(Landfill gas)를 대기 중으로 방출할 경우에 매립지가스에서 많은 부분을 차지하고 있는 지구온난화 지수(global warming potential)가 높은 메탄가스를 배출하게 되어 기후변화에 악영향을 주게 되고, 매립지가스에 함유되어 있는 메탄을 내연기관의 연료로 활용하여 연소하여 발전을 하게 되면 이산화탄소 형태로 대기 중으로 배출하게 되어 온난화 지수를 낮추는 데도 기여를 할 수 있게 된다. 따라서 매립지가스를 내연기관을 이용한 발전용 연료로 사용하기 위해서 엔진의 열효율을 높이는 것이 중요하기 때문에 기존의 믹서 방식 기술을 이용한 연료공급 방식보다는 실린더별로 흡기포트에서 전자 제어 인젝터를 이용하여 기체 분사를 하는 방식의 연료공급 시스템을 사용하는 것이 필요하게 된다. 따라서 전자 제어 기체 분사 방식 기술을 이용하기 위해서는 매립지가스의 사용 조건에 따른 질량 유량을 정확히 측정하는 것이 중요하게 된다. 이를 위하여 본 연구에서는 매립지가스를 기체 분사할 경우에 분사량을 측정 및 계산하는 연구를 수행하였다.

• 대한기계학회논문집A
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• 제40권4호
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• pp.337-342
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• 2016

스퍼드캔(spudcan)은 잭업리그(jack-up rig)의 다리 하단에 장착되며, 해저면에 구조물을 안정적으로 지지하여 구조물의 전복사고를 방지하기 위한 장치이다. 표층이 모래 층일 때는 침투(penetration) 시에 스퍼드캔을 안정적으로 삽입하기 위해서, 그리고 점토 층일 때는 회수(extraction) 시에 원활하게 뽑아 올리기 위해서 스퍼드캔에는 물 분사장치가 장착되어 있다. 본 연구에서는 물 분사장치를 위한 배관라인용 홀의 형상을 최적화하기 위해 크게 타원형과 원형 두 가지 형상을 설정하였다. 해석을 위해 대상 Site 는 멕시코만(Gulf of Mexico)로 선정하였고 대상 플랫폼은 해상풍력발전기설치선(WTIV)을 선택하였다. 상용프로그램인 ANSYS Workbench 를 사용하여 최적설계를 진행하였다. 본 연구결과는 다양한 해양구조물의 홀 형상설계에 적용될 수 있다.

• Journal of Korean Neurosurgical Society
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• 제42권2호
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• pp.118-124
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• 2007

Objective : Adipose tissue is derived from the embryonic mesoderm and contains a heterogenous stromal cell population. Authors have tried to verify the characteristics of stem cell of adipose derived stromal cells (ADSCs) and to investigate immunohistochemical findings after transplantation of ADSC into rat brain to evaluate survival, migration and differentiation of transplanted stromal cells. Methods : First ADSCs were isolated from human adipose tissue and induced adipose, osseous and neuronal differentiation under appropriate culture condition in vitro and examined phenotypes profile of human ADSCs in undifferentiated states using flow cytometry and immunohistochemical study. Human ADSCs were transplanted into the healthy rat brain to investigate survival, migration and differentiation after 4 weeks. Results : From human adipose tissue, adipose stem cells were harvested and subcultured for several times. The cultured ADSCs were differentiated into adipocytes, osteoctye and neuron-like cell under conditioned media. Flow cytometric analysis of undifferentiated ADSCs revealed that ADSCs were positive for CD29, CD44 and negative for CD34, CD45, CD117 and HLA-DR. Transplanted human ADSCs were found mainly in cortex adjacent to injection site and migrated from injection site at a distance of at least 1 mm along the cortex and corpus callosum. A few transplanted cells have differentiated into neuron and astrocyte. Conclusion : ADSCs were differentiated into multilineage cell lines through transdifferentiation. ADSCs were survived and migrated in xenograft without immunosuppression. Based on this data, ADSCs may be potential source of stem cells for many human disease including neurologic disorder.

• The Korean Journal of Pain
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• 제23권4호
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• pp.230-235
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• 2010

Background: Bone cancer pain has a disruptive effect on the cancer patient's quality of life. Although ginsenosides have been used as traditional medicine in Eastern Medicine, the effect on bone cancer pain has not been throughly studied. The aim of this study was to determine whether ginsenosides may alter the bone cancer pain at the spinal level. Methods: NCTC 2472 tumor cells ($2.5{\times}10^5$) were injected into the femur of adult male C3H/HeJ mice to evoke bone tumor and bone cancer pain. To develop bone tumor, radiologic pictures were obtained. To assess pain, the withdrawal thereshold was measured by applying a von Frey filament to the tumor cells inoculation site. The effect of intrathecal ginsenosides was investigated. Effect of ginsenosides (150, 500, $1,000{\mu}g$) was examined at 15, 30, 60, 90, 120 min after intrathecal delivery. Results: The intrafemoral injection of NCTC 2472 tumor cells induced a radiological bone tumor. The withdrawal threshold with tumor development was significantly decreased compared to the sham animals. Intrathecal ginsenosides effectively increased the withdrawal threshold in the bone cancer site. Conclusions: NCTC 2472 tumor cells injection into the mice femur caused bone tumor and bone cancer pain. Intrathecal ginsenosides attenuated the bone cancer-related pain behavior. Therefore, spinal ginsenosides may be an alternative analgesic for treating bone cancer pain.