• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 제5회 압연심포지엄 신 시장 개척을 위한 압연기술
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• pp.175-183
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• 2004

In hot strip rolling, a capability for precisely predicting roll force is crucial for sound process control. In the past, on-line prediction models have been developed mostly on the basis of Orowan's theory and its variation. However, the range of process conditions in which desired prediction accuracy could be achieved was rather limited, mainly due to many simplifying assumptions inherent to Orowan's theory. As far as the prediction accuracy is concerned, a rigorously formulated finite element(FE) process model is perhaps the best choice. However, a FE process model in general requires a large CPU time, rendering itself inadequate for on-line purpose. In this report, we present a FE-based on-line prediction model applicable to precision process control in a finishing mill(FM). Described was an integrated FE process model capable of revealing the detailed aspects of the thermo-mechanical behavior of the roll-strip system. Using the FE process model, a series of process simulation was conducted to investigate the effect of diverse process variables on some selected non-dimensional parameters characterizing the thermo-mechanical behavior of the strip. Then, it was shown that an on-line model for the prediction of roll force could be derived on the basis of these parameters. The prediction accuracy of the proposed model was examined through comparison with measurements from the hot strip mill.

• 반도체디스플레이기술학회지
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• 제12권2호
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• pp.79-84
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• 2013

Nanoimprint lithography (NIL) is the next generation photolithography process in which the photoresist is dispensed onto the substrate in its liquid form and then imprinted and cured into a desired pattern instead of using traditional optical system. There have been considerable attentions on NIL due to its potential abilities that enable cost-effective and high-throughput nanofabrication to the display device and semiconductor industry. Although one of the current major research trends of NIL is large-area patterning, the technical difficulties to keep the uniformity of the residual layer become severer as the imprinting area increases more and more. In this paper, with the rolling type imprinting process, a mold, placed upon the $2^{nd}$ generation TFT-LCD glass sized substrate($370{\times}470mm^2$), is rolled by a rubber roller to achieve a uniform residual layer. The prediction of residual layer thickness of the photoresist by rolling of the rubber roller is crucial to design the rolling type imprinting process, determine the rubber roller operation conditions-mpressing force & feeding speed, operate smoothly the following etching process, and so forth. First, using the elasticity theory of contact problem and the empirical equation of rubber hardness, the contact length between rubber roller and mold is calculated with consideration of the shape and hardness of rubber roller and the pressing force to rubber roller. Next, using the squeeze flow theory to photoresist flow, the residual layer thickness of the photoresist is calculated with information of the viscosity and initial layer thickness of photoresist, the shape of mold pattern, feeding speed of rubber roller, and the contact length between rubber roller and mold previously calculated. Last, the effects of rubber roller operation conditions, impressing force & feeding speed, on the residual layer thickness are analyzed with consideration of the shape and hardness of rubber roller.

• Nuclear Engineering and Technology
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• 제49권1호
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• pp.148-164
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• 2017

The focus on the issues surrounding spent nuclear fuel and lifetime extension of old nuclear power plants continues to grow nowadays. A transparent decision-making process to identify the best suitable nuclear fuel cycle (NFC) is considered to be the key task in the current situation. Through this study, an attempt is made to develop an equilibrium model for the NFC to calculate the material flows based on 1 TWh of electricity production, and to perform integrated multicriteria decision-making method analyses via the analytic hierarchy process technique for order of preference by similarity to ideal solution, preference ranking organization method for enrichment evaluation, and multiattribute utility theory methods. This comparative study is aimed at screening and ranking the three selected NFC options against five aspects: sustainability, environmental friendliness, economics, proliferation resistance, and technical feasibility. The selected fuel cycle options include pressurized water reactor (PWR) once-through cycle, PWR mixed oxide cycle, or pyroprocessing sodium-cooled fast reactor cycle. A sensitivity analysis was performed to prove the robustness of the results and explore the influence of criteria on the obtained ranking. As a result of the comparative analysis, the pyroprocessing sodium-cooled fast reactor cycle is determined to be the most competitive option among the NFC scenarios.

• 한국전자파학회논문지
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• 제28권2호
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• pp.155-158
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• 2017

전자, 통신 기술의 발달로 대부분의 장소에서 전자기기가 존재한다. 자동차, 열차, 항공기 등 다양한 장소에서 전자기기의 활용이 증가된 만큼 고출력 전자기파로 인한 오작동과 하드웨어의 치명적인 손상을 확인할 수 있는 안전성을 연구하는 것이 중요하게 되었다. 구조물 내부에 전자기기 및 여러 센서를 연결하는 케이블은 전자기파에 의한 오작동을 초래할 수 있는 원인 중 하나이기 때문에 전자파 영향에 대한 해석이 필수적이다. 본 논문에서는 상관관계 함수와 전송이론을 이용하여, 전기적으로 큰 공진기 내부에 존재하는 케이블에 유기되는 전류를 계산해 외부 전자기파에 의한 영향을 해석하였다.

• 한국조경학회지
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• 제43권3호
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• pp.92-100
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• 2015

대부분의 일반적인 계획 과정과 달리, 브라운필드 계획은 잠재된 오염문제로 인한 기술적, 법률적 전문지식을 필요로 한다. 성공적으로 통합적인 의사결정에 관여하기 위해서는 조정된 협력적 계획 모델이 중요하다. 본 연구는 기존의 협력적 계획 접근방식이 브라운 필드 재생에 있어 상반된 분야의 전문가들 및 지역 주민들이 함께 일하며 적절하게 균형 잡힌 협력을 이루어 내기 위한 어려움들을 극복하는 데에 어떻게 효과적으로 적용될 수 있는지 알아보는 것을 목표로 한다. 의사소통적 계획이론 관련 문헌분석을 통해 적절한 지표들을 찾아내어, 네 단계의 브라운 필드 계획과정(대상지 선별, 평가, 정화, 디자인)에 적용시켜 본 후, 중요한 부분들을 짚어내었다. 본 연구의 결과, 크게 세 가지 점에 초점을 맞춘, 브라운 필드 재생에 적합한 협력적 계획 모델의 필요성이 인식되었다(1. 사회, 문화, 디자인 분야와 과학, 기술 분야의 전문가 간의 균형 잡힌 대화의 촉진, 2. 일반주민들과의 잠재적 오염 위험과 관련한 커뮤니케이션을 위한 적절한 방법개발, 3. 전문가 주도의 객관적 데이터와 주민 의견 중심의 주관적 데이터의 통합을 위한 의사결정지원 시스템의 마련).

• 한국지리정보학회지
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• 제11권3호
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• pp.80-91
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• 2008

UIS사업의 결과로 나온 공간데이터의 경우 막대한 비용투자에 비하여 활용의 정도는 기대에 미치지 못하고 있으며 공간데이터의 활용확대를 위하여 데이터의 효율적 관리 및 공유체계의 확립을 위한 노력은 반드시 필요하다. 본 연구는 지방자치단체내에서 공간 데이터의 효율적인 관리 및 공유체계확립과 공간데이터의 활용 확대를 위하여 사회연결망 분석 및 계획행동이론을 적용하였으며 부산광역시 공간데이터 사용 공무원을 대상으로 분석결과 공간데이터의 공유에 영향을 미치는 장애요인에는 데이터 사용자들간의 태도 및 주변과의 관계에서 발생하는 비기술적 장애요인의 비중이 높게 나타났다. 또한 데이터의 제공위치에 따라 공간데이터 공유의 장애요인에 대하여 다르게 인식하고 있는 것으로 나타났으며 이러한 사회적 신념이 행동의도에 영향을 미쳐서 또 다른 비기술적 장애요인이 발생하였다. 본 연구는 공간데이터의 활용확대를 위하여 인간의 행동예측을 위한 계획행동이론의 적용 및 공간데이터의 흐름을 파악하기 위한 사회연결망분석을 실시하여 부서에 속한 담당자들의 인식 및 공유장애요인을 규명하고 데이터 활용 확대로 접근할 수 있는 윤곽을 제시하였다.

• 한국식품영양학회지
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• 제2권1호
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• pp.61-72
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• 1989

This study was conducted to gather the baseline data on realities of experimental-practice and opinions toward spot-practice, and to examine how to cope with the problems raised at the Department of Food and Nutrition of Junior Technical College in Korea. Questionnaires were gathered from 42 chairmans of the Department of Food and Nutrition and 140 Present dieticians worked in Seoul, Bucheon am Seongnam area. The results are as follows, First, as a whole, each college had 2~3 experimental laboratory (Lab), in which Cooking Science Lab. Chemistry Lab and Microbiology Lab were occurred at higher frequency as Lab's name. Second, the numbers per experimental-practice class were more than 40 at most colleges. 85% of Present dieticians have answered to feel too much numbers per the class during their college days, whereas professors' opinions toward the numbers per class were suitable at 20~30 persons per class. Third, professors' opinion toward the adquate ratio of the theory subject classes to experimental subject classes was suitable at 60 : 40. Dieticians answered to take the theory subject classes partly or mostly on behalf of the experimental-practice classes. Fourth, the main reasons which inhibited normal experimental-practice class were the class for emphasis on examination, the shortage of experiment budget, the excess of class members, the shortage of experimental Lab Also, this results showed same propensity to present dieticians' opinion toward the same question above. Fifth, among the experimenta1-practice subjects established at the Department of Food and Nutrition, Diet Therapy Lab was highest frequency class emphasized on theory followed by Nutrition Counselling Lab, Food Processing and Storage Lab, Food Hygiene Lab and Food Microbiology Lab in that order. Here, Basic Chemistry Lab, Biochemistry Lab, Food Microbiology Lab were pointed as subjects far from the present task of dieticians. Sixth, Department of Food and Nutrition, as a whole, has conferred with spot-practice arrangement About 50% (all who want to join spot-practice) of second year students took part in spot-practice. In the other way, all colleges except for 2 colleges didn't give the credit for the spot-practice system. Seventh, according to the on analysis on spot-practice places, manufacturing company was at highest frequcney followed by hospitals, elementary school having group feeding system in that order. Especially, 16.7% (5 colleges) of the total colleges sent the students to the research institute related to food industry for spot-practice experience. Eighth, Professors' opinions toward the spot-practice time and period were preferable on summer vacation of second year and for 1~2 weeks, respectively. On the contrary, 74 dieticians answered to the adquate period as for 4 weeks. Ninth, 86 dieticians of the total 140 answered to complete the spot-practice during their college days, which helps the present task of them. Lacks of spot-practice program, Lacks of comprehension of upper personals and lacks of group feeding equipments ranks higher as difficulties in spot-practice management.

• 한국지구과학회지
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• 제18권6호
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• pp.464-472
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• 1997

과학교사 교육의 목표는 우리 사회가 필요로 하는 가장 이상적이고 훌륭한 과학교사를 양성하는데 두고 있으며, 양성 교육과정은 전문적 이론과 실제를 통한 수준 높은 학술적 체험과 활동 과정을 거쳐 '유능한 과학교사'와 동시에 '존경받는 스승'을 양성하는 과정이어야 한다. 따라서 중등학교 과학교사의 양성 체제와 임용 제도의 문제점 및 그 개선 방안은 첫째, 임용시험 제도 폐지와 수습 교사 제도를 도입하거나, 공 사립학교가 공히 공개 임용시험제도를 도입해야 한다. 둘째, 과학교사 양성 교육과정의 개편으로 과학내용학, 과학교육학의 협동적 연구를 강화하고 현장의 요구와 교육과정의 연계를 구현하며 셋째, 교사 양성 기관의 행 재정적 지원 체제를 확립하여 우수 과학교사 양성이 가능하도록 해야 한다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.544-544
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• 2014

Energy harvesting technology, which scavenges electric power from ambient, otherwise wasted, energy sources, has been explored to develop self-powered wireless sensors and possibly eliminate the battery replacement cost for wireless sensors. Among ambient energy sources, vibration energy can be converted into electric power through a piezoelectric energy harvester. For the last decade, although tremendous advances have been made in design methodology to maximize harvestable electric power under a given vibration condition, the research in reliability assessment to ensure durability has been stagnant due to the complicated nature of the multiple failure modes of a piezoelectric energy harvester, such as the interfacial delamination, fatigue failure, and dynamic fracture. Therefore, this study presents the first-ever system reliability analysis for multiple failure modes of a piezoelectric energy harvester using the Generalized Complementary Intersection Method (GCIM), while accounts for the energy conversion performance. The GCIM enables to decompose the probabilities of high-order joint failure events into probabilities of complementary intersection events. The electromechanically-coupled analytical model is implemented based on the Kirchhoff plate theory to analyze its output performances of a piezoelectric energy harvester. Since a durable as well as efficient design of a piezoelectric energy harvester is significantly important in sustainably utilizing self-powered electronics, we believe that technical development on system reliability analysis will have an immediate and major impact on piezoelectric energy harvesting technology.

• 대한조선학회논문집
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• 제42권3호
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• pp.259-267
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• 2005

The effects of hull flexibility on shaft alignment are growing as ship sizes are increased mainly for container carrier and LNG carrier. In order to consider hull flexibility on a propulsion shafting system, standardization of ship service conditions is necessary because hull deformation is continuously variable according to ship service conditions. How to summarize ship service conditions is suggested based on practically applicable four viewpoints : hull, engine, loading and sea status. Effects of the external forces acting on a ship propulsion shafting system are generally commented. Several design criteria regulated by classification societies are pointed at issue which seems to have Insufficient technical background. A qualitative verification is carried out to point out the invalidity of the assumption of effective supporting position. In this work, an elastic nonlinear multi-supporting bearing system is introduced as a key concept of the elastic shaft alignment. Hertz contact theory is proved to be more proper one than projected area method in calculation of the nonlinear elastic stiffness of the bearing, The squeezing and oil film pressure calculations in the long journal bearing like an after stern tube bearing are recognized as a necessary process for elastic shaft alignment design.