• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.596-601
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• 2020

Silicon carbide is considered a potentially useful material for high-temperature electronic devices because of its large band gap energy and p-type or n-type conduction that can be controlled by impurity doping. Accordingly, the thermoelectric properties of -SiC powder prepared by refined diatomite were investigated for high value-added applications of natural diatomite. -SiC powder was synthesized by a carbothermal reduction of the SiO₂ in refined diatomite using carbon black. An acid-treatment process was then performed to eliminate the remaining impurities (Fe, Ca, etc.). n-Type semiconductors were fabricated by sintering the pressed powder at 2000℃ for 1~5h in an N2 atmosphere. The electrical conductivity increased with increasing sintering time, which might be due to an increase in carrier concentration and improvement in grain-to-grain connectivity. The carrier compensation effect caused by the remaining acceptor impurities (Al, etc.) in the obtained -SiC had a deleterious influence on the electrical conductivity. The absolute value of the Seebeck coefficient increased with increasing sintering time, which might be due to a decrease in the stacking fault density accompanied by grain or crystallite growth. On the other hand, the power factor, which reflects the thermoelectric conversion efficiency of the present work, was slightly lower than that of the porous SiC semiconductors fabricated by conventional high-purity -SiC powder, it can be stated that the thermoelectric properties could be improved further by precise control of an acid-treatment process.

• Journal of radiological science and technology
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• v.38 no.4
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• pp.389-394
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• 2015

There is a progressive development in the medical imaging technology, especially of descriptive capability for anatomical structure of human body thanks to advancement of information technology and medical devices. But however maintenance of correct posture is essential for the medical imaging checkup on the shoulder joint requiring rotation of the upper limb due to the complexity of human body. In the cases of MRI examination, long duration and fixed posture are critical, as failure to comply with them leads to minimal possibility of reproducibility only with the efforts of the examiner and will of the patient. Thus, this study aimed to develop an auxiliary device that enables rotation of the upper limb as well as fixing it at quantitative angles for medical imaging examination capable of providing diagnostic values. An auxiliary device has been developed based on the results of precedent studies, by designing a 3D model with the CATIA software, an engineering application, and producing it with the 3D printer. The printer is Objet350 Connex from Stratasys, and acrylonitrile- butadiene-styrene(ABS) is used as the material of the device. Dimensions are $120{\times}150{\times}190mm$, with the inner diameter of the handle being 125.9 mm. The auxiliary device has 4 components including the body (outside), handle (inside), fixture terminal and the connection part. The body and handle have the gap of 2.1 mm for smooth rotation, while the 360 degree of scales have been etched on the handle so that the angle required for observation may be recorded per patient for traceability and dual examination.

• Journal of the Korean association of regional geographers
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• v.9 no.1
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• pp.53-65
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• 2003

The aim of this study is to examine the regional features of shipbuilding-allied industries comprehensively. Inaddition, this study would offer groundwork to construct spatial networks of shipbuilding-allied industries. Relatively in short term, large modem shipbuilding firms of South Korea have developed under the national strategic support, around southeast coast region. Although small shipbuilding firms and marine equipment firms have supported regional economy, these firms have scaled down their functions and roles due to the national policy. In the long tenn, Korean shipbuilding-allied industries have limitations in stable development, because they have separated their roles. Consequently it is necessary the balanced development of large, medium, and small shipbuilding firms and linkage system with marine equipment firms for overall development of shipbuilding-allied industries. This study suggests two spatial strategy for shipbuilding-allied industries development. First, we need to construct a shipbuilding specialization area which agglomerates competent parts firms adjacent to large shipyards. Second, in national strategy, a long term strategy is required to utilize extremely synergy and external effects induced from a shipbuilding duster of southeast coast region which systematically combines shipbuilding-allied industries, universities, the government authorities, and research institutions.

• Proceedings of the Membrane Society of Korea Conference
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• 1996.06a
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• pp.91-120
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• 1996

경제발전과 더불어 산업의 많은 분야에서 순수 및 초순순의 사용이 증가하고 있으나, 환경오염에 의한 원수의 오염에 따라 순수 및 초순순제조의 장치비와 처리비용의 증가가 야기되고 있다. 현재 국내에는 화력, 원자력발전소를 비롯하여 열병합발전소, 석유화학공장, 제약회사, 전기 전자부품회사, 반도체회사 및 철강회사 등 많은 분야에서 순수 및 초순수 제조장치의 구성과 성능이 많은 차이를 나타내고 있다. 국내의 초순수 제조장치는 90% 이상이 이온교환수지를 사용하는 이온교환법과 UF, R/O System과 같은 Membrane을 사용하는 Membrane System을 병행하여 적용하고 있다. 국내 초순수처리 Plant에서는 통상 전처리 System과 1차 순수제조 System 및 초순수 System이 상호 연결되어 Plant가 구성 운영되고 있다. 전처리 System에는 응집침전, 여과 흡착, 살균 등이 적용되고 있으며 여과 System에 Membrane을 적용할 수 있으나 국내에서는 특별한 경우를 제외하고 대부분 전처리 여과 System에 Media Filter를 사용한다. 전처리 System도 순수처리 장치의 전처리로는 없어서는 안되는 System이지만 여기에는 전처리 System을 제외하고 국내에서 적용하고 있는 초순수처리 System의 공정현황과 각 System별 특징을 설명하고 있다. 초순순 System에는 요구 수질에 따라 다소 차이가 있지만 반도체 공업에서 사용되는 초순수 System이 이중 최고의 Grade로 반도체공업에서 적용되고 있는 System을 기준하였다. 특히 Membrane을 적용한 초순수제조 System이 증가하고 있어 R/O, ED, EDR, CDI, (EDI)와 같은 Membrane System의 특성과 원리를 검토하였다.대적으로 높은 산소확산계수와 물에 대해서는 낮은 투과도를 가져야 한다. 높은 산소확산계수는 반응을 빠르게 하는 잇점이 있으며 물에 대한 낮은 투과도는 센서내의 전해질 물질을 유지보호하는 역할을 한다. 분리막이 산소전극에 이용될 경우 높은 산소 확산계수 이외에도 적절한 기계적 강도, 열적 안정성 등이 요구된다. 몰입이 가능하여 임계치가 저하된 것으로 여겨진다. 또한 광학적 이득의 존재는 이 구조에 의한 극단파장 반도체 레이저다이오드의 실현 가능성을 나타내는 것이다.548 mL에 비해 통계학적으로 의의 있게 적었다(p<0.05). 결론: 관상동맥우회로 조성수술에서 전방온혈심정지액을 사용할 때 희석되지 많은 고농도 포타슘은 fliud overload와 수혈을 피하고 delivery kit를 사용하지 않음으로써 효과적이고 만족할 만한 심근보호 효과를 보였다.를 보였다.4주까지에서는 비교적 폐포는 정상적 구조를 유지하면서 부분적으로 소폐동맥 중막의 비후와 간질에 호산구 침윤의 소견이 특징적으로 관찰되었다. 결론: 분리 폐 관류는 정맥주입 방법에 비해 고농도의 cisplatin 투여로 인한 다른 장기에서의 농도 증가 없이 폐 조직에 약 50배 정도의 고농도 cisplatin을 투여할 수 있었으며, 또한 분리 폐 관류 시 cisplatin에 의한 직접적 폐 독성은 발견되지 않았다이 낮았으나 통계학적 의의는 없었다[10.0%(4/40) : 8.2%(20/244), p>0.05]. 결론: 비디오흉강경술에서 재발을 낮추기 위해 수술시 폐야 전체를 관찰하여 존재하는 폐기포를 놓치지 않는 것이 중요하며, 폐기포를 확인하지 못한 경우와 이차성 자연기흉에 대해서는 흉막유착술에 더 세심한 주의가 필요하다는 것을 확인하였다. 비디오흉강경수술은 통증이 적고, 입원기간이 짧고, 사회

• Proceedings of the CALSEC Conference
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• 1999.07a
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• pp.41-50
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• 1999

최근의 CALS 시스템 구축 가속화 및 전자상거래 활성화 분위기는 정보기술의 전략적 활용의 초점을 개별기업 위주에서 기업간 협력체제 구축과 이를 바탕으로 하는 기업간 전자적 결합(Electronic Integration)으로 옮기고 있다. 우리는 정보기술의 공유를 기반으로 새로운 기업간의 관계를 구축할 수 있으며, 이러한 관계를 전략적으로 활용함으로써 기존 사업에서의 경쟁우위 뿐만 아니라, 새로운 사업기회를 창출할 수 있다. 관련기업간의 데이터 표준화를 통한 정보의 공유는 CALS 시스템 구축의 바탕이 된다고 할 수 있는데, 정보공유의 범위는 산업별 특성과 제품별 특성에 따라 달라질 수밖에 없으며, 관련기업간의 교섭력(Bargaining Power)에 의해서도 영향을 받게된다. CALS 환경에서는 개별기업의 정보전략에 따라 수직적 협력관계에 있는 기업들간의 정보공유 정도와 수평적 협력관계에 있는 기업들간의 정보공유 정도가 결정된다고 할 수 있다. 정보공유의 범위를 설정하는 데에는 기업간에 이루어지는 업무의 성격, 공급-제조-유통으로 연결되는 관련기업간의 구조 등도 크게 영향을 미치는 것으로 파악되고 있다. 이 연구에서는 CALS 시스템 구축과정에서 우리가 고려할 수 있는 정보공유의 범위를 관련업무공유, 시스템공유, 부품 설비공유, 시설공유 등의 관점에서 분석하여 봄으로써, 각 산업별로 진행되고 있는 시범사업들의 시스템 영역의 범위를 재조명해보고자 한다. 이 연구에서 집중적으로 다루게 될 정보공유의 범위에 대한 내용은 CALS 시스템을 개발하려는 기업들의 응용서비스 개발 및 정보전략 구축에 중요한 공헌을 할 수 있을 것으로 기대된다.진" 사업에 대한 표준 설정을 위하여 노스캐롤라이나주 지방보건소의 "보건교육/건강증진" 표준체제를 예로 들었다. 다음으로, 경제적인 효율면에서 볼 때 "보건교육/건강증진" 사업에는 단기 혹은 장기 투자가치가 있는가 하는 것이다. 새로 태어나는 미국 지방 보건소의 "보건교육/건강증진" 활동은 지역 시민 및 그 단체가 광범위하고도 자연 다발적으로 참여할 때만 성공할 수 있다고 결론 지울 수 있다.한 분야별 전문가시스템 개발을 지양하고 MCRDR이론을 기반으로 한 범용성 있는 전문가시스템 개발 툴의 개발에 관한 연구를 소개한다. 후 새로운 지식을 얻는 반복적인 Explanation-based Data Mining Architecture를 제시하였다. 본 연구의 의의로는 데이타 마이닝을 통한 귀납적 지식생성에 있어 귀납적 오류의 발생을 고메인 지식을 통해 설명가능 함을 보임으로 검증하고 아울러 이러한 설명을 통해 연역적으로 새로운 가설지식을 생성시켜 이를 가설검증방식으로 검증함으로써 귀납적 접근과 연역적 접근의 통합 데이타 마이닝 접근을 제시하였다는데 있다.gical learning to give information necessary to improve the making. program and policy decision making, The objectives of the study are to develop the methodology of modeling the socioeconomic evaluation, and build up the practical socioeconomic evaluation model of the HAN projec

• Journal of the Korean Institute of Gas
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• v.14 no.6
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• pp.15-20
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• 2010

Compressed Natural Gas (CNG) buses have been supplied since the year 2000 in order to resolve severe atmospheric pollution in metropolitan area and contributed on the improvement of urban atmospheric environment. However, it is indispensible to take an adequate measure to guarantee the safety of CNG vehicles because of the possibility of huge fire accident. A receptacle, connecting device between high pressure fuel supply tank and fuel line, plays an important role in CNG supply system. In recent, leakage of CNG from receptacles has been reported. So, the concern about the security and reliability of receptacles has been arisen. Therefore, a lot of efforts to prevent leakage are invested among researchers and the durability of this component should be guaranteed despite repeated operation. This research has performed durability tests of a CNG receptacle regarding the repeated usage, extreme chattering, and continuous full flow test. Although a receptacle used for CNG vehicle satisfies validation requirements in the test results, it has been found that failure in the function of leakage prevention in a receptacle could take place in the case of prolonged exposure to high supply pressure in common quick charging environment on site.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.3
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• pp.105-110
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• 2022

In line with the trend of the 4th Industrial Revolution, we tried to study the scalability of the craft sector in the art field in the wake of the convergence of new fields through the combination of different fields. To this end, a craft case using 3D printing technology was analyzed based on the theoretical background of the definition and value of digital craft. As a result of the study, craft works using 3D printing technology could be divided into four forms according to the fusion expression method. First, the mixed type was most characterized by harmonious production without significantly deviating from the traditional craft type. Second, the component type was produced in the form in which the characteristics of digital technology, which has advantages of certain shapes and detailed work, were best exhibited. Third, the structural type became a work with analog sensibility by adding traditional craft techniques based on the results output from a 3D printer. Finally, the connection type was the work that showed the greatest glimpse of originality and uniqueness among the analysis cases of this study. As digital technology is positively widely used, future studies will also deal with effective work directions.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.1
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• pp.90-94
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• 2023

Carbon fiber(CF) with excellent thermal conductivity and electrical conductivity is attracting attention as an alternative material because metal heating elements have problems such as high heat loss and fire risk. However, since CF is oxidized and disconnected at about 200℃ or higher, the application of heating elements is limited, and CF heating elements in the form of vacuum tubes are currently used in some commercial heaters. In this work, polyimide(PI) with high heat resistance was coated on the surface of carbon fiber by electrophoretic deposition to prevent oxidation of CF in the atmosphere without using a vacuum tube, and the coating thickness and heat resistance were investigated according to the applied voltage. The heater made by connecting the PI-coated CF heating elements in series showed stable heating characteristics up to 292℃, which was similar to the heating temperature result of the heat transfer simulation. The PI layer coated by the electrophoretic deposition method is effective in preventing oxidation of CF at 200℃ or higher and is expected to be applicable to various heating components such as secondary batteries, aerospace, and electric vehicles that require heat stability.

• Journal of the Korean Society of Safety
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• v.14 no.1
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• pp.208-215
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• 1999

The creep behavior of a rapidly solidified and consolidated Al-9.45wt%Fe-4.45wt%Cr alloy were investigated in the stress range 40 to 115 MPa and temperature range 300(0.53Tm) to 441$^{\circ}C$(0.66Tm). It is of use to available aerospace and automobile industries for the improved performance of materials used at high temperature. Because Al alloys with improved creep resistance offer the potential for lower weight and reduced costs in aerospace and automobile components (e.g., structural members and engine parts) through the replacement of heavier and more costly materials, the safety in use at high temperature is good. The alloy is characterized by high stress exponents and activation energies for creep, which are greatly dependent on the stress and temperature. Because the creep stress is seen to cause a strongly significant enhancement of coarsening, the coarsening rate of the dispersed particles in all crept specimens is faster than that in isothermally annealed specimens. Dislocations connecting dispersoids are observed more cofrequently in crept specimens with higher stress and lower temperature. The creep strain rates in the power law creep regime were found to be predicted much better by the Shorty and Rosler/Arzt equation with the inclusion of a threshold stress and dislocation detachment mechanism. The dispersoids in this alloy were acting a source of void nucleation that finally leaded to ductile fracture within the grain so called intergranular. Each void was initiated, grown and failed at the dispersoids in the aluminium matrix. Grain boundary accommodation of the slip produced, which result in initiation of the void and then final transgranular fracture. Therefore, it was confirmed that these dispersoids played an important role in the fracture mechanism by the formation of $Al_{13}Fe_4$, $Al_{13}Cr_2$ and $Al_2O_3$.

• Journal of Technology Innovation
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• v.26 no.3
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• pp.37-68
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• 2018

Since the 20th century, automobiles, which are the most common means of transportation, have been evolving as the use of electronic control devices and automotive semiconductors increases dramatically. Automotive semiconductors are a key component in automotive electronic control devices and are used to provide stability, efficiency of fuel use, and stability of operation to consumers. For example, automotive semiconductors include engines control, technologies for managing electric motors, transmission control units, hybrid vehicle control, start/stop systems, electronic motor control, automotive radar and LIDAR, smart head lamps, head-up displays, lane keeping systems. As such, semiconductors are being applied to almost all electronic control devices that make up an automobile, and they are creating more effects than simply combining mechanical devices. Since automotive semiconductors have a high data rate basically, a microprocessor unit is being used instead of a micro control unit. For example, semiconductors based on ARM processors are being used in telematics, audio/video multi-medias and navigation. Automotive semiconductors require characteristics such as high reliability, durability and long-term supply, considering the period of use of the automobile for more than 10 years. The reliability of automotive semiconductors is directly linked to the safety of automobiles. The semiconductor industry uses JEDEC and AEC standards to evaluate the reliability of automotive semiconductors. In addition, the life expectancy of the product is estimated at the early stage of development and at the early stage of mass production by using the reliability test method and results that are presented as standard in the automobile industry. However, there are limitations in predicting the failure rate caused by various parameters such as customer's various conditions of use and usage time. To overcome these limitations, much research has been done in academia and industry. Among them, researches using data mining techniques have been carried out in many semiconductor fields, but application and research on automotive semiconductors have not yet been studied. In this regard, this study investigates the relationship between data generated during semiconductor assembly and package test process by using data mining technique, and uses data mining technique suitable for predicting potential failure rate using customer bad data.