• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2002년도 추계학술대회 논문집
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• pp.301-306
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• 2002

The characteristics of parameters for the probability distribution of fatigue crack growth lives by the non-Gaussian random process simulation method is investigated. In this paper, the material resistance to fatigue crack growth is treated as a spatial random process, which varies randomly on the crack surface. Using the previous experimental data, the crack length - the number of cycles curves are simulated. The results are obtained for constant stress intensity factor range conditions with stress ratio of R=0.2, three specimen thickness of 6, 12 and 18mm, and the four stress intensity level. The probability distribution function of fatigue crack growth lives seems to follow the 3-parameter Wiubull and shows a slight dependence on specimen thickness and stress intensity level. The shape parameter, ${\alpha}$, does not show the dependency of thickness and stress intensity level, but the scale parameter, ${\beta}$, and location parameter, ${\upsilon}$, are decreased by increasing the specimen thickness and stress intensity level. The slope for the stress intensity level is larger than the specimen thickness.

• Geomechanics and Engineering
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• 제31권5호
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• pp.453-460
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• 2022

It is essential for geotechnical engineers to conduct studies and make predictions about the stability of slopes, since collapse of a slope may result in catastrophic events. The Gaussian process regression (GPR) approach was carried out for the purpose of predicting the factor of safety (FOS) of the slopes in the study that was presented here. The model makes use of a total of 327 slope cases from Iran, each of which has a unique combination of geometric and shear strength parameters that were analyzed by PLAXIS software in order to determine their FOS. The K-fold (K = 5) technique of cross-validation (CV) was used in order to conduct an analysis of the accuracy of the models' predictions. In conclusion, the GPR model showed excellent ability in the prediction of FOS of slope stability, with an R² value of 0.8355, RMSE value of 0.1372, and MAPE value of 6.6389%, respectively. According to the results of the sensitivity analysis, the characteristics (friction angle) and (unit weight) are, in descending order, the most effective, the next most effective, and the least effective parameters for determining slope stability.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.84-89
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• 2003

Fuzzy controller is one of the succeed controller used in the process control in case of model uncertainties. But it my be difficult to fuzzy controller to articulate the accumulated knowledge to encompass all circumstance. Hence, it is essential to provide a tuning capability. There are many parameters in fuzzy controller can be adapted, scale factor tuning of normalized fuzzy controller is one of the adaptation parameter. Two adaptation methods are implemented in this work on an experimental thermal process, which simulate heating process in liquefied petroleum gases (LPG) recovery process in one of petrochemical industries: Gradient decent (GD) adaptation method; supervisory fuzzy controller. A comparison between the two methods is discussed.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.286-293
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• 2003

Our Railroad has been decided to convert the system from government enterprise to privitization since 1989. But These Policy has been changed 3times. Therefore I wish to survey the proecss, which is the main factor to change the policy. Firstly, I made a hypothesis concerning the policy making process. Secondly, I described the policy process concisely. Thirdly, I analysized the policy making process. In conclusion, I suggested the rational policy process model.

• Bulletin of the Korean Chemical Society
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• 제26권11호
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• pp.1823-1825
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• 2005

Angiogenesis is tightly regulated by a variety of angiogenic activators and inhibitors. Disruption of the balanced angiogenesis leads to the progress of diseases such as cancer, rheumatoid arthritis, and diabetic blindness. Even though a number of proteins involved in angiogenesis have been identified so far, more protein factors remain to be identified due to complexity of the process. Here I report that pituitary tumor-transforming gene (PTTG) induces migration and tube formation of human umbilical vein endothelial cells (HUVECs). High levels of both vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) are detected in conditioned medium obtained from cells transfected with PTTG expression plasmid. Taken together, these results suggest that PTTG is an angiogenic factor that induces production of both VEGF and bFGF.

• 소성∙가공
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• 제3권2호
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• pp.215-228
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• 1994

The purpose of this paper is to pursue a general method to determine both the flow stress of a material and the friction factor by ring compression test. The materials are assumed to obey the expanded n-power hardening rule including the strain-rate effect. Ring compression is simulated by the rigid-plastic finite element method to obtain the database used in determining the flow stress and friction factor. The Simulation is conducted for various strain hardening exponent, strain-rate sensitivity, friction factor, and compressing speed, as variables. It is assumed that the friction factor is constant during the compression process. To evaluate the compatibility of the database, experiments are carried out at room and evaluated temperature using specimens of aluminum 6061-T6 under dry and grease lubrication condition. It is shown that the proposed test method is useful and easy to use in determining the flow stress and the friction factor.

• KSBB Journal
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• 제23권1호
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• pp.37-43
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• 2008

(주)녹십자는 1986년 "훽나인"을 B형 혈우병 치료제로 제조품목허가를 받아 B형 혈우병치료제 공급을 시작하였다. 또한 1991년 New York Blood Center에서 selvent/detergent 바이러스 불활화 방법을 도입하여 제조공정에 추가한 후 혈액유래 바이러스로부터 안전한 제품을 생산하여 왔다. 하지만 이 제품은 혈액응고 제2인자, 제7인자, 제10인자가 함유된 제9인자 복합체로, 정맥 혈전증과 파종성 혈관내응고병증 같은 혈전형성 부작용이 일어날 가능성이 있어, 훽나인보다 순도, 유효성, 바이러스 안전성이 우수한 제품의 개발이 필요하였다. 이를 위해 고순도 제9인자 제제인 "GreenNine VF" 제조공정을 개발하였다. GreenNine VF 제조공정은 기존의 훽나인 생산 공정에 heparin 친화성 크로마토그래피와 양이온 크로마토그래피가 추가된 공정으로, 바이러스 안전성을 증진시키기 위한 바이러스 필터 공정도 포함하고 있다. 이러한 공정에 의해서 산업적 규모로 생산된 GreenNine VF는 훽나인에 비해 순도와 바이러스 안전성이 월등히 높은 것으로 확인되었다. 또한 고순도 혈액응고 제9인자 제제인 Mononine, Octanyne, Berinin HS, Immunine STIM plus 600보다 순도가 더 높았다. Cryo-poor plasma 1,600 L를 원료로 사용했을 때 1 batch 당 250IU 분병제품 2,400병 이상, 500 IU 분병제품 1,200병 이상을 생산할 수 있었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.265-271
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• 1992

It is the purpose of this paper to present a dialogical designing method for control system using a rough grasp of the unknown process property. We deal with a single-input single-output feedback control system with a fuzzy controller. The process property is roughly estimated by the step response, and the fuzzy controller is interactively modified according to the operator's requests. The modifying rules mainly derived from computer simulation are useful for almost every process, such as an unstable process and a non-minimum phase process. The fuzzy controller is tuned by taking notice of four characteristics of the step response: (1) rising time, (2) overshoot, (3) amplitude and (4) period of vibration. The tuning position of the controller is fourfold: (1) antecedent gain factor GE or GCE, (2) consequent gain factor GDU, (3) arrangement of the antecedent fuzzy labels and (4) arrangement of the control rules. The rules give an instance to the respective items of the controller in an effective order. The modified fuzzy PI controller realizes a good response of a stable process. However, because the GDU tuning becomes difficult for the unstable process, it is necessary to evaluate the stability of the process from the initial step response. The fuzzy PI controller is applied to the process whose initial step response converges with GDU tuning. The fuzzy PI controller with modified sampling time is applied to the process whose step response converges under the repeated application of the GDU tuning. The fuzzy PD controller is applied to the process whose step response never converges by the GDU tuning.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.149-154
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• 2007

The zinc prosphate film treatments used to lubricating treatment of mostly cold forging processes. But there are several problems happened to lubricating treatment process such as happening harmful environment on person, complex lubrication processing occurring in energy and time consumption, eco-destructive and chemical by-product generation, the needs of waste disposal etc. As a result, a water-soluble lubricant was developed to replace the perfect or some of the zinc prosphate film in the world. In order to solve these problems, this study evaluated the performance of the typical water-soluble. In this study, for these requirement inquiry of two part. First, about possibility of replace zinc phosphate lubricant, quantitatively evaluation developed of water-soluble lubricant for cold forging vs zinc phosphate lubricant. Second, About optimization of coating Process use to equipment with practicable automatic coating Process. The performance evaluation of these lubricants was conducted using the double cup extrusion test and spike forging test. With the use of the commercial FE code DEFORM, friction factor calibration curves, i.e. cup height ratio vs. punch stroke and spike height vs. punch stroke, were established for different friction factor values. By matching the cup height ratio and the punch stroke and spike height vs. punch stroke from experiment to that obtained from FE simulations, the friction factor of the lubricants was determined. Survey of comparative analysis use to SEM that sprayed lubricant surface structure of grain shape and characteristic of lubricant performance based on grain shape and deformed lubricant surface expansion. As a result, developed lubricant were found to perform comparable to or better than zinc phosphate. And thought this result, innovatively cope with generated problem of existing lubrication process.

• 기술혁신학회지
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• 제12권1호
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• pp.113-136
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• 2009

국가 연구개발사업의 효율성과 생산성을 제고하기 위하여, 정부에서는 '국가연구개발사업 등의 성과 평가 및 성과관리에 관한 법률'을 제정하여 정부 각 부처의 연구개발 사업 성과의 효율성을 증대시키고 있다. 본 논문은 국방연구개발사업 자체평가시스템 측면에서 메타평가를 실시하기 위하여 요인분석(Factor Analysis)을 통한 계층분석적 의사결정기법(AHP, Analytic Hierarchy Process)을 사용한 평가지표를 개발한 결과이다. 국방연구개발사업의 메타평가를 위한 평가요소로서 평가상황, 평가투입, 평가수행, 평가결과 등 4요소로 구분하여 평가지표를 개발하였다. 평가항목 선정을 위하여 평가요소 및 평가지표간 요인분석을 실시하여 Cronbach's ${\alpha}$ 값을 측정한 결과, 평가상황요소는 0.877, 평가투입요소는 0.755, 평가결과요소는 0.792, 평가결과요소는 0.906으로 내적일관성을 고려한 신뢰성은 있는 것으로 나타났다. 그리고 평가요소 및 평가항목별 가중치 산정은 AHP기법을 사용하여 분석하였다. 분석결과 조사자의 전체 일관성 지수는 0.09로 조사자의 일관성은 있는 것으로 분석되었다.