• Proceedings of the Korean Environmental Sciences Society Conference
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• 2006.11a
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• pp.421-424
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• 2006

종래의 개발은 양면성을 가지고 있다. 하나는 개발로 인한 경제적 효율성과 편리성 부분이고, 다른 하나는 그러한 개발로 인한 자연훼손 및 생태계 파괴이다. 이로 인해 개발과 보전은 양립할 수 없는 상반적인 개념으로 받아들여져 왔고, 개발론과 보전론의 대립적 구도가 지속되어 왔다. 우리나라는 국토의 65% 이상이 산지이기 때문에 산지의 부분적 개발은 피할 수 없는 사회적 요구인 동시에, 산지는 자연생태계의 보고로서 생태계 보전이 필수적인 지역이다. 이러한 산지 개발과 보전에 대한 상반적 이해를 통합하여 자연과 인간의 공생체계를 갖추기 위해서는 인간중심의 사고에서 탈피하여 사람과 생태계 그리고 자연을 하나로 보는 총체적인 측면에서 접근하는 새로운 패러다임이 설정되어야 한다. 본 연구에서는 산지의 정량적인 가치를 평가하기 위해 시 공간적으로 다양한 인자들에 대해 시스템적인 관점에서 그 중요성을 고려하고자 하는 에머지 개념을 통해 산지 본래의 가치를 평가하였다. 에머지 개념은 그 동안 생태계가치평가, 개발사업의 편익-비용평가, 환경수용력 평가, 개발대안 평가, 환경계정, 환경훼손 소송관련 비용 평가 등에 적용되었다. 이러한 에머지 개념을 이용한 평가 방법을 통한 의사결정이 이루어지면 산지뿐만이 아닌 생태계의 지속가능한 이용을 실현하기 위한 적절한 정책의 선택과 이의 이행 실효성을 높일 수 있을 것으로 기대되며, 자연환경 가치의 정량적 평가를 통해서 우리는 한층 더 자연환경 및 자원의 다원적 기능에 대한 자각을 할 수 있을 것으로 판단된다.

• Journal of Digestive Cancer Research
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• v.4 no.1
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• pp.17-20
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• 2016

Colorectal cancer is the 2^nd most common cancer in men, and the 3^rd most common cancer in women in Korea. This incidence has been increasing steadily since the data analysis began in 1999. Guidelines from many countries including Korea recommend annual or biennial fecal occult blood test as a national colorectal cancer screening program, however, colonoscopy, stool DNA test, double contrast barium enema, and sigmoidoscopy are recommended in some countries. I will summarize the Korean National Screening Guideline for colorectal cancer revised by multi-society expert committee in Korea last year. They recommend annual or biennial fecal immunochemical test between 45 and 80 year-old asymptomatic average risk people. Selective use of colonoscopy is recommended, taking into consideration of individual preference and the risk of colorectal cancer. There is no evidence for the risks or benefits of double contrast barium enema or computed tomographic colonography for colorectal cancer screening.

• Clean Technology
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• v.17 no.2
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• pp.103-109
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• 2011

The process optimization was carried out to improve the throwing power (TP) and the thickness uniformity of the electroless copper (Cu) plating, which plays a seed layer for the subsequent electroplating. The DOE (design of experiment) was employed to screen key factors out of all available operation parameters to influence the TP and thickness uniformity the most. It turned out that higher Cu ion concentration and lower plating temperature are advantageous to accomplish uniform via filling and they are accounted for based on the surface reactivity. To visualize what occurred experimentally and evaluate the phenomena qualitatively, the kinetic Monte Carlo (MC) simulation was introduced. The combination of neatly designed experiments by DOE and supporting theoretical simulation is believed to be inspiring in solving similar kinds of problems in the relevant field.

• Clinical and Experimental Reproductive Medicine
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• v.35 no.4
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• pp.303-308
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• 2008

Purpose: The purpose of this study is to determine the effect of preoperative semen parameters on both seminal improvement and pregnancy rates following varicocelectomy. Methods: This survey was done in 278 patients who underwent microsurgical inguinal varicocelectomy from January 2001 until October 2006. By the total motile sperm counts (TMSC) before operation, the patients were stratified into three groups. Group A (mild oligoasthenospermia) was defined as above 20 million, group B (moderate oligoasthenospermia) was defined as between 5 and 20 million, and group C (severe oligoasthenospermia) was defined as below 5 million. Improvement rates of TMSC and pregnancy rates following varicocelectomy of each groups were compared. Results: The average TMSC of all the patients was 25.75 million before operation and after operation, it was 80.24 million, showing an average increase of 54.49 million (211.6%). To take a look at mean absolute increase (mean relative increase proportion), group A showed 67.90 million (131.2%), group B 62.20 million (482.5%) and group C 26.33 million (1841.2%). The patients with varicocele whose semen parameter is in bad condition show relatively a low mean absolute increase but high mean relative increase proportion. There was no significant difference in natural pregnancy rate among each groups (p=0.119, p=0.059). Conclusions: Even in the varicocele patient whose semen parameter was in bad condition before surgical operation. varicocelectomy could be chosen as the first treatment to male infertility.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.6
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• pp.517-524
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• 2017

The objective of this research is to improve the efficiency of data collection from many machine components on smart factory floors using IoT(Internet of things) techniques and cloud platform, and to make it easy to update outdated diagnostic schemes through online deployment methods from cloud resources. The short-term analysis is implemented by a micro-controller, and it includes machine-learning algorithms for inferring snapshot information of the machine components. For long-term analysis, time-series and high-dimension data are used for root cause analysis by combining a cloud platform and multivariate analysis techniques. The diagnostic results are visualized in a web-based display dashboard for an unconstrained user access. The implementation is demonstrated to identify its performance in data acquisition and analysis for rotating machinery.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.4
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• pp.316-322
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• 2019

A probabilistic approach considering uncertainties was employed to investigate the effects on the material characteristics and strength of nuclear bio-logical shield concrete walls, when exposed to long-term radiation during the entire service life. Time-dependent compressive and tensile strengths were estimated by conducting the neutron fluence analysis. For the contaminated concrete, individual compressive and tensile failure probabilities can be possibly evaluated by not only establishing limit-state function withthe predefined critical values but also performing Monte Carlo Simulation. Nuclear power plant types similar to the Kori Unit 1, which was shut off permanently in 2017 after the 40-year operation, were herein selected for an illustrative purpose. Consequently, the probability-based performance assessment and prediction of contaminated concrete walls were well demonstrated.

• Journal of Korea Water Resources Association
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• v.30 no.5
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• pp.561-570
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• 1997

The feature of this paper is (1) to analyze the characteristics of rainfall-runoff relationship with kinematic wave theory, (2) to study the computational model to estimate the sediment yield, (3) to analyze the effects of bed change by transport formulas and the number of watershed division, and (4) to verify the model application with observation of channel data and measurement of rainfall, runoff, sediment discharge in Pyung-Chang River Basin. The calculated time of concentration of peak discharge occured little earlier than the actual, but the tendency of hydrograph coincided with observation. The shape of sediment hydrographs was similar to the water hydrograph. Based on above results, the applicability of the model was verified in detail. As the number of watershed division increased, the difference between the measured runoff and sediment values and the estimated ones decreased. The result of calculation with Yalin's formula for surface and Acker-White's one for channel gave the best agreement with the measured data among the six selected sediment transport foumulas.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.332-332
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• 2016

수공구조물 설계시 hardware와 software의 발달로 수리계산과 수치해석의 오차율이 감소함에 따라 수치해석을 이용하는 빈도가 높아지고, 신뢰도가 향상되고 있는 추세에 있다. 그러나 댐 설계에 있어 수위별 방유량 관계 검토시 수치해석값은 각 수위에 해당하는 몇 개의 유량값을 대응시켜 경향만 비교하고 수리계산 결과를 설계에 반영해 왔다. 이러한 방법은 여수로 주변에 인접구조물이 없고, 여수로 각 수문별 균등한 유량이 방류될 경우 문제가 되지 않지만, 여수로 직상류 지형에 만곡부나 지형적 특성이 여수로 방류에 영향을 미치거나, 취수탑 등 여수로에 인접한 수리구조물이 설치되어 접근수로에서 복잡한 유동을 형성하는 경우 각 문비마다 방류량의 분배율은 달라질 수밖에 없고, 수리계산 결과를 일괄 반영하기에는 오차가 증가할 수밖에 없다. 이에 본 연구에서는 댐 운영시 중요한 인자 중 하나인 수위-방류량 관계에 대하여 수치모형을 이용한 정밀한 분석을 통하여 댐 여수로 운영시 오차율을 저감시키고, 적용성을 향상시키는 방안을 검토하였다. 첫째, 수위별 방류량 관계 검토시 여수로 상류에서 일정한 시간에 따라 선형적으로 수위가 증가하도록 경계조건을 설정한 후 3차원 수치해석 모형의 Output data를 단위시간에 따라 수위와 방류량이 산정되도록 하고, 기존 검토 방식대로 각 수위별 모형을 steady 상태로 수행하여 비교분석하였다. 수리계산과 기존 방식, 본 연구에서 제시한 방법에 대한 오차율 검토 결과 오차는 3 % 이내로 검토되었다. 둘째, 수치해석을 이용하여 수위별 방류량 산정시 접근유속에 대한 영향을 받게 되므로 수리계산시 에너지 경사를 이용하여 수위값을 반영하지만, 수치해석을 이용하여 수위별 방류량 산정시 경계조건을 부여한 수위값을 반영하거나, 임의의 지점에서의 수위값을 반영하는 경우 등 일괄적이지 않은 수위값을 반영하여 오차율이 증가하는 경향이 있다. 따라서, 본 연구에서는 여수로 지점별 전수두를 측정하여 방류량 값을 산정하여 비교하였다.

• Radiation Oncology Journal
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• v.20 no.2
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• pp.130-138
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• 2002

Purpose : This study analyzed the prognostic factors affecting the survival rate and evaluated the role of radiation therapy in muscle-invading bladder cancer. Materials and Methods : Twenty eight patients with bladder cancer who completed planned definitive radiotherapy in the Departments of Therapeutic Radiology and Urology, Chonnam National University Hospital between Jan. 1986 to Dec. 1998 were retrospectively analyzed. The reviews were peformed based on the patients' medical records. There were 21 males and 7 females in this study. The median of age was 72 years old ranging from 49 to 84 years. All patients were confirmed as having transitional cell carcinoma with histological grade 1 in one patient, grade 2 in 15, grade 3 in 9, and uninformed in 3. Radiation therapy was peformed using a linear accelerator with 6 or 10 MV X-rays. Radiation was delivered daily with a 1.8 or 2.0 Gy fraction size by 4 ports (anterior-posterior, both lateral, alternatively) or 3 ports (Anterior and both lateral). The median radiation dose delivered to the isocenter of the target volume was 61.24 Gy ranging from 59 to 66.6 Gy. The survival rate was calculated by the Kaplan-Meier method. Multivariate analysis was peformed on the prognostic factors affecting the survival rate. Results : The survival rate was $76\%,\;46\%,\;33\%,\;33\%$ at 1, 2, 3, 5 years, respectively, with 19 months of median survival. The potential factors of age (less than 70 years vs above 70), sex, diabetes mellitus, hypertension, hydronephrosis, 1-stage (T3a vs T3b), TUR, chemotherapy, total duration of radiotherapy, radiation dose (less than 60 Gy vs above 60 Gy), and the treatment response were investigated with uniand multivariate analysis. Un univariate analysis, the T-stage (p=0.078) and radiation dose (p=0.051) were marginally significant, and the treatment response (p=0.011) was a statistically significant factor on the survival rate. Multivariate analysis showed there were no significant prognostic factors affecting the survival rate. Conclusion : The treatment response and radiation dose are suggested as th은 statistically significant factors affecting the survival rate of muscle invasive bladder cancer. A Further prospective randomized study is needed to confirm these prognostic factors.

• Tunnel and Underground Space
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• v.24 no.2
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• pp.155-165
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• 2014

Multiple thermal energy storage (TES) caverns can be used for storing thermal energy on a large scale and for a high-aspect-ratio heat storage design to provide good thermal performance. It may also be necessary to consider the use of multiple caverns with a reduced length when a single, long tunnel-shaped cavern is not suitable for connection to aboveground heat production and injection equipments. When using multiple TES caverns, the separation distance between the caverns is one of the significant factors that should be considered in the design of storage space, and the optimal separation distance should be determined based on a quantitative stability criterion. In this paper, we described a numerical approach for determining the optimal separation distance between multiple caverns for large-scale TES utilization. For reliable stability evaluation of multiple caverns, we employed a probabilistic method which can quantitatively take into account the uncertainty of input parameters by probability distributions, unlike conventional deterministic approaches. The present approach was applied to the design of a conceptual TES model to store hot water for district heating. The probabilistic stability results of this application demonstrated that the approach in our work can be effectively used as a decision-making tool to determine the optimal separation distance between multiple caverns. In addition, the probabilistic results were compared to those obtained through a deterministic analysis, and the comparison results suggested that care should taken in selecting the acceptable level of stability when using deterministic approaches.