• Journal of Korean Neurosurgical Society
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• v.48 no.6
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• pp.480-484
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• 2010

Objective : To evaluate the role of lumbar drainage in the prevention of shunt-dependent hydrocephalus after treatment of ruptured intracranial aneurysms by coil embolization in good-grade patients. Methods : One-hundred-thirty consecutive patients with aneurysmal subarachnoid hemorrhage in good-grade patients (Hunt & Hess grades I-III), who were treated by coil embolization between August 2004 and April 2010 were retrospectively evaluated. Poor-grade patients (Hunt & Hess grades IV and V), a history of head trauma preceding the development of headache, negative angiograms, primary subarachnoid hemorrhage (SAH), and loss to follow-up were excluded from the study. We assessed the effects on lumbar drainage on the risk of shunt-dependent hydrocephalus related to coil embolization in patients with ruptured intracranial aneurysms. Results : One-hundred-twenty-six patients (96.9%) did not develop shunt-dependent hydrocephalus. The 2 patients (1.5%) who developed acute hydrocephalus treated with temporary external ventricular drainage did not require permanent shunt diversion. Overall, 4 patients (3.1%) required permanent shunt diversion; acute hydrocephalus developed in 2 patients (50%). There was no morbidity or mortality amongst the patients who underwent a permanent shunt procedure. Conclusion : Coil embolization of ruptured intracranial aneurysms may be associated with a lower risk for developing shunt-dependent hydrocephalus, possibly by active management of lumbar drainage, which may reflect less damage for cisternal anatomy than surgical clipping. Coil embolization might have an effect the long-term outcome and decision-making for ruptured intracranial aneurysms.

• Journal of the Korean Society of Safety
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• v.35 no.5
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• pp.30-38
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• 2020

In order to construct a dam, the diversion facility such as cofferdam and a diversion tunnel should be installed in advance. And size of a cofferdam depends on type of a main dam. According to the Korea Dam Design Standard, if the main dam is a concrete dam, design flood of the cofferdam is 1~2 years flood frequency. This means that overflow of the cofferdam occurs one time for 1 or 2 years, therefore, stability of the cofferdam should be secured against any overflow problem. In this study, failure probability analysis for the concrete cofferdam is performed considering the overflow. First of all, limit state function of the concrete cofferdam is defined for overturning, sliding and base pressure, and upstream water levels are set as El. 501 m, El. 503 m, El. 505 m, El. 507 m. Also, after literature investigation research, probabilistic characteristics of various random variables are determined, the failure probability of the concrete cofferdam is calculated using the Monte Carlo Simulation. As a result of the analysis, when the upstream water level rises, it means overflow, the failure probability increases rapidly. In particular, the failure probability is largest in case of flood loading condition. It is considered that the high upstream water level causes increase of the upstream water pressure and the uplift pressure on the foundation. In addition, among the overturning, the sliding and the base pressure, the overturing is the major cause for the cofferdam failure considering the overflow.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1064-1072
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• 2015

This study attempted to identify the motivational factors for using athletes' SNS among Chinese sports fans. The researchers posted a hyperlink of an online survey on a total of 8 Chinese Olympians' SNS(Weibo) accounts after obtaining the athlete's approval. A total of 274 surveys were gathered from the visitors of SNS. Of the 274 surveys, 33 were discarded because of missing values. Confirmatory factor analysis and structural equation modeling revealed the following. Diversion, pass-time, athlete support, and technical knowledge were significantly and positively related to social media consumption while information, socialization, and fanship had no significant predictive effect on social media consumption.

• Journal of Korea Water Resources Association
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• v.41 no.10
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• pp.1067-1077
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• 2008

An understanding of temporal trends of stream flows can help in the river management and the water resources planning for natural circumstances and human communities. Changes in temperature, precipitation, flow, and land use (agriculture, flood prevention activities, reservoir operation, interbasin diversion, etc.) are all eventually reflected in the flow pattern of the river. An assumption that the stationarity of the hydrologic series implying time-invariant characteristics of the time series accepted in water structure designs can no longer be valid if the flow changes as a result of the climate change or the stream flow use. Therefore, the identification and description of the characteristics of changes in hydrologic time series is a very important task in the river basin management. In this study, the statistical tests on the flow change forced by excess water diversions in the Sumjin River basin were performed by ways of single variable and time series variable comparisons. The tests showed that currently the Sumjin River basin statistically keeps its homogeneity in annual streamflow series, but the changed situation has been appeared in dry season streamflow series.

• Journal of Korean Society of Transportation
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• v.30 no.6
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• pp.81-92
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• 2012

The current Korean preliminary feasibility study guidebook provides a simple method for determining the impact area of a transportation project without taking its characteristics into account, which often leads travelers to switch their travel modes. Hence, this study develops a comprehensive methodology for defining the impact area when evaluating railroad projects, which can significantly affect travel mode choice behaviors. To develop the methodology, a hypothetical project was devised. The analysis results show that the convergence of mode-diverted trip rates is improved from 76% to 93% by implementing the proposed method. In addition, there was a significant difference in benefits (about 10.9 billion won) between adopting the current method and the proposed method.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.358-358
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• 2016

본 연구에 앞서 가뭄에 따른 충청남도 서부권의 물 부족을 해결하기 위하여 금강 본류로부터 보령댐으로 일정 유량을 도수(diversion)하는 계획이 금강 본류에 미치는 수리적 영향을 1차원 비정상류 해석(unsteady flow analysis)을 통하여 분석하였으며, 본 연구에서는 수리모형 결과와 연계하여 수질 모형을 구축하여 금강 본류 수질에 미치는 영향을 알아보고자 하였다. 조위 영향에 따른 염도의 역류 모의를 위하여 전자해도와 위성영상자료를 활용하여 금강 하굿둑에서 외해 방향으로 약 9km에 이르는 모의 구간을 확장하였으며, 상류단의 진두수위표를 포함한 8개 지천의 유입유량 및 수질, 하구의 조위와 염도, 농공용수 취수시설의 취수량 및 회귀수 수질, 금강 배수갑문 운영, 대상 구간에 인접한 기상대의 기상자료 등을 고려하고 금강 본류를 따라 9개 수질측정소의 수질자료를 이용하여 모형의 보정을 실시하였다. 또한 대상 구간 내 2015년의 갈수기 유황 분석을 토대로 비선형 회귀분석식을 도출하여 2016년 갈수기 예측 유량과 함께 수질-유량 관계식을 도출하여 대상 구간의 수온, 염도, 용존산소(DO), BOD, 조류 등 영향을 분석하였다. 수온 분석 결과, 지점에 따라 2015년 유황 대비 평균 수온 1.79~3.83도, 최고 수온 1.74~4.30도 상승할 것으로 모의되었으며, 염도는 2016년 갈수기 동안의 금강 하굿둑 외해 염도는 담수 방류량의 감소로 전년 동기 대비 평균 53% 증가하는 것으로 모의되어 기수역 생태계에 상당한 영향을 줄 것으로 분석되었으며, 갈수기 동안의 금강 하굿둑 내수의 염도는 배수갑문 개방 빈도, 개방 시간, 개방 정도의 감소에 따른 해수 역류의 감소로 전년 동기 대비 크게 감소할 것으로 모의되었다. 용존산소는 2016년 갈수기 동안의 용존산소 농도는 지점에 따라 전년 동기 대비 평균 4~11% 감소하는 것으로 모의되었으며, 2016년 갈수기 동안의 BOD 농도는 지점에 따라 전년 동기 대비 평균 30~57% 증가하는 것으로 분석되었다. 조류는 지점에 따라 전년 동기 대비 평균 29~67% 증가하는 것으로 모의되었다. 유량의 감소에 따른 수온 증가 및 수질 악화의 영향이 있을 것으로 분석되나, 도수에 따른 영향은 상대적으로 제한적인 것으로 분석되었다.

• Annals of Surgical Treatment and Research
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• v.95 no.6
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• pp.319-323
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• 2018

Purpose: Currently, many operations are performed using the single-incision laparoscopic method. Although there have been recent reports on single-incision laparoscopic ileostomy, none have compared this method to conventional laparoscopic ileostomy. This study aimed to assess the safety and feasibility of single-incision laparoscopic ileostomy for anastomotic leakage following laparoscopic low anterior resections. Methods: From April 2012 to April 2017, 38 patients underwent laparoscopic ileostomy (single-incision; 19 patients referred to as group A, conventional laparoscopy; 19 patients referred to as group B) for anastomotic leakage following laparoscopic low anterior resection. We analyzed surgical and clinical outcomes between the 2 groups. Patients in whom a protective ileostomy was carried out during the initial laparoscopic low anterior resection were excluded from this study. Results: No significant differences were observed between the 2 groups in terms of patient demographics and initial operation details. Incisional surgical site infections occurred less in group A than in group B (2 of 19 vs. 9 of 19, P = 0.029). The median ileostomy operation time, amount of intraoperative bleeding, parastomal hernia ratio, hospital stay duration after ileostomy, postoperative pain score were not significantly different between the 2 groups. Conclusion: Single-incision laparoscopic ileostomy is safe and feasible method of fecal diversion for anastomotic leakage following laparoscopic low anterior resection.

• Education of Primary School Mathematics
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• v.22 no.1
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• pp.1-12
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• 2019

This study examined the attention and attention shift of general students and mathematically gifted students about pattern by the types of mathematical patterns. For this purpose, we analyzed eye movements during the problem solving process of 5th general and mathematically gifted students using eye tracker. The results were as follows: first, there was no significant difference in attentional style between the two groups. Second, there was no significant difference in attention according to the generation method between the two groups. The diversion was more frequent in the incremental strain generation method in both groups. Third, general students focused more on the comparison between non-contiguous terms in both attributes. Unlike general students, mathematically gifted students showed more diversion from geometric attributes. In order to effectively guide the various types of mathematical patterns, we must consider the distinction between attention and attention shift between the two groups.

• Journal of Korean Neurosurgical Society
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• v.64 no.4
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• pp.619-630
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• 2021

Objective : The skull base reconstruction step, which prevents cerebrospinal fluid (CSF) leakage, is one of the most challenging steps in endoscopic skull base surgery (ESS). The purpose of this study was to assess the outcomes and complications of a reconstruction technique for immediate CSF leakage repair using multiple onlay grafts following ESS. Methods : A total of 230 consecutive patients who underwent skull base reconstruction using multiple onlay grafts with fibrin sealant patch (FSP), hydroxyapatite cement (HAC), and pedicled nasoseptal flap (PNF) for high-flow CSF leakage following ESS at three institutions were enrolled. We retrospectively reviewed the medical and radiological records to analyze the preoperative features and postoperative results. Results : The diagnoses included craniopharyngioma (46.8%), meningioma (34.0%), pituitary adenoma (5.3%), chordoma (1.6%), Rathke's cleft cyst (1.1%) and others (n=21, 11.2%). The trans-planum/tuberculum approach (94.3%) was the most commonly adapted surgical method, followed by the trans-sellar and transclival approaches. The third ventricle was opened in 78 patients (41.5%). Lumbar CSF drainage was not performed postoperatively in any of the patients. Postoperative CSF leakage occurred in four patients (1.7%) due to technical mistakes and were repaired with the same technique. However, postoperative meningitis occurred in 13.5% (n=31) of the patients, but no microorganisms were identified. The median latency to the diagnosis of meningitis was 8 days (range, 2-38). CSF leakage was the unique risk factor for postoperative meningitis (p<0.001). Conclusion : The use of multiple onlay grafts with FSP, HAC, and PNF is a reliable reconstruction technique that provides immediate and complete CSF leakage repair and mucosal grafting on the skull base without the need to harvest autologous tissue or perform postoperative CSF diversion. However, postoperative meningitis should be monitored carefully.

• Imaging Science in Dentistry
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• v.51 no.1
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• pp.9-16
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• 2021

Purpose: The purpose of this study was to analyze the reliability of 7 panoramic radiographic signs for predicting proximity of the root apices of mandibular third molars to the mandibular canal using cone-beam computed tomography and to correlate these findings with the Pell and Gregory and the Winter classification systems. Materials and Methods: An observational, cross-sectional, descriptive study was conducted on 74 patients with bilateral impacted mandibular third molars. Four panoramic radiographic signs were observed in the tooth root (darkening, deflection, and narrowing of the root apices, and bifid apices), and another 3 in the mandibular canal (diversion, narrowing, and interruption of the mandibular canal). Cone-beam computed tomography images were analyzed to identify disruption and diversion of the mandibular canal and root deflection. Results: Binary logistic regression showed that only 4 of the 7 panoramic radiographic signs were able to predict proximity of the root apices of the mandibular third molars to the mandibular canal: darkening of the root, deflection of the root, narrowing of the root, and interruption of the mandibular canal(P<0.05). Conclusion: Darkening, deflection, and narrowing of the root, in tandem with the interruption of the mandibular canal on panoramic radiographs, indicate that cone-beam computed tomography should be performed when planning the extraction of impacted mandibular third molars. Proximity between mandibular third molars and the mandibular canal is correlated with the Winter classification.