• Journal of the Korean Electrochemical Society
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• v.12 no.2
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• pp.155-161
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• 2009

Lithium secondary batteries have been widely used in the portable electric devices as power source. Recently it is expected that the realm of its applications expands to the markets such as energy storage medium of hybrid electric vehicle(HEV), electric vehicle(EV). Cathode active material is crucial in terms of performance, durability, capacity of lithium secondary batteries. It is urgent to develope the technology for mass production of cathode material to cope with the markets' demands in the near future. In this study, a calcination furnace running in real production line is modelled in 3D, and the thermal flow and gas flow after chemical reaction in the furnace is analyzed through numerical computations. Based on the results, it is shown that large volume of $CO_2$ gas is generated from chemical reaction. High concentration of $CO_2$ gas and it's stagnation is clearly found from the reactant containers in which the reaction occur to the bottom area of the furnace. It is also studied that 15% or more $CO_2$ mol fraction could affect to proper formation of $LiCoO_2$ through TGA-DSC analysis. The solutions to evacuate carbon dioxide from the furnace are suggested through the change of furnace design and operating condition as well.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.19-19
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• 2009

최근, 유한한 에너지 자원의 한계와 지구 온난화 등으로 세계의 제조 산업은 새로운 국면을 맞이하고 있으며, 특히, 자동차 산업은 화석연료를 주 에너지원으로 사용한다는 점과 이 연료를 연소시킬 때 발생하는 이산화탄소가 지구 온난화의 주된 원인이 될 수 있다는 점에서 상기 문제들을 해결하기 위한 다양한 방법에 주목하고 있다. 그 중에서 자동차의 생산기술 측면에서 볼 때, 가장 중요한 이슈는 차체 경량화다. 자동차 차체는 자동차를 구성하고 있는 여러 가지 부품 중에서 약 40% 정도의 무게 비율을 차지하고 있기 때문에, 차체 경량화는 연비향상과 이산화탄소 배출가스 감소와 직접적인 관계를 가지고 있다. 다양한 차체 경량화 방법 중에서 가장 쉽게 접근할 수 있는 방법이 경량소재 적용에 의한 경량화 방법이다. 현재, 탄소섬유 강화 플라스틱과 같이 무게 절감 비율을 최대화 할 수 있는 소재들도 개발되어 일부 적용되고 있지만, 일반적으로 차체 경량화 소재로 가장 널리 사용되고 있는 소재는 알루미늄 합금이며, 이에 대한 차체 적용 비율이 점차로 높아지는 추세에 있다. 이에, 본 연구에서는 알루미늄 합금이 차체에 적용되었을 때의 장단점을 살펴보고, 알루미늄 합금을 적용한 차체 생산과정에서 유의해야 될 사항들과 이를 바탕으로 하는 생산성 극대화 방안에 대하여 고찰하였다. 먼저, 기존의 알루미늄 저항 점 용접공법의 단점을 최소화하고 대량생산 체계에 적합하도록 개발된 새로운 개념의 저항 점 용접 시스템에 대해 그 성능과 양산성을 검증하였다. 구리 전극과 알루미늄 피용접물 사이에 프로세스 테이프를 삽입하여 용접하는 이 시스템은 열전도성이 큰 알루미늄 용접부에서 저전류의 조건에서도 효과적으로 균일한 발열현상이 발생하게 하였으며, 전극 팁 드레싱 없이 모든 용접점이 항상 동일한 조건에서 용접이 이루어질 수 있도록 하였다. 용접 조건 설정에 있어서도 용접전류가 통전되는 순간에 전극 가압력을 자유로이 변형시켜 용접부 크랙 발생을 최소화할 수 있음을 확인하였다. 알루미늄의 또 다른 대표적인 접합방법인 아크용접에 있어서는 용접 입열량을 조절하여 용접변형을 최소화 할 수 있는 아크용접 시스템에 대해 양산성과 적용 타당성을 검토하였다. 와이어 송급 방향을 자유자재로 바꿀 수 있는 이 시스템의 특성에 의해 스패터를 최소화하면서 용융금속이 효과적으로 모재에 금속이행 될 수 있음을 확인하였으며, 판재, 압출재, 및 다이캐스팅재 등 다양한 차체 소재에 대한 용접 가능성 및 미그-레이저 하이브리드 용접과의 비교분석을 통하여 차체 박판 용접에서도 최소의 열변형으로 효과적으로 사용될 수 있음을 보였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.4
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• pp.768-779
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• 2017

Recently, the great number of mobile devices causes excessive data/control traffic problems in the centralized LTE/EPC network and such dramatically increased traffic is emerging as a critical issue. In the Centralized Mobility Management (CMM) based LTE/EPC network, the Packet Data Network Gateway (P-GW) plays the centralized mobility anchor role and it accommodates most of data traffic. To solve this problem, the IETF has proposed the Distributed Mobility Management (DMM) scheme, but it has only focused on the data traffic load balancing and could not solve the control traffic overload problem. In this paper, therefore, we propose a new SDN based hybrid CMM/DMM Mobility Management (C-DMM) architecture based on Packet Network Edge Gateway (P-EGW), and introduce a selection scheme between CMM and DMM according to a device's mobility and the number of PDN connections. In order to prove the efficiency of the proposed architecture and scheme, we compare the data traffic processing load and the control traffic processing load over each scheme by emulating them in the ONOS controller and the Mininet environment.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.477-480
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• 2002

Si-O-C(-H) thin film with a tow dielectric constant were deposited on a P-type Si(100) substrate by an inductively coupled plasma chemical vapor deposition (ICPCVD). Bis-trimethylsilymethane (BTMSM, H$_{9}$C$_3$-Si-CH$_2$-Si-C$_3$H$_{9}$) and oxygen gas were used as Precursor. Hybrid type Si-O-C(-H) thin films with organic material have been generated many voids after annealing. Consequently, the Si-O-C(-H) films can be made a low dielectric material by the effect of void. The surface characterization of Si-O-C(-H) thin films were performed by SEM(scanning electron microscope). The characteristic analysis of Si-O-C(-H) thin films were performed by X-ray photoelectron spectroscopy (XPS).

• Proceedings of the CALSEC Conference
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• 1999.11a
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• pp.280-293
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• 1999

본 연구는 경영학 관련 분야에서 멀티미디어 기술의 경영학적 측면의 응용에 관한 연구의 중요성이나 필요성을 많은 학자들이 인식하고 있음에도 불구하고 아직 멀티미디어에 관한 연구가 전무한 실정에서 시도한 초기연구라는데 연구의 의의가 있다. 이러한 시점에서 교육공학과 경영정보학을 접목시킨 멀티미디어에 관한 연구는 상당히 중요할 것으로 판단된다. 이와 같이 본 연구는 경영정보학 분야에서 멀미미디어에 관한 연구로서는 초기의 연구로서, 본 연구가 가지는 연구의 필요성이나 중요성에 대해서는 우리들이 충분히 인식할 수 있을 것이다. 지금까지 국내외적으로 멀티미디어 정보시스템을 이용한 교육의 효과에 관한 연구는 몇 편의 탐색적 논문이 발견되고 있으나, 멀티미디어를 이용한 교육의 효과를 구성하는 요인이 무엇인지를 밝히기 위한 연구는 거의 전무한 실정이다 이러한 상황에서 멀티미디어를 이용한 교육의 효과를 구성하는 요인이 무엇이며, 구성요인 중 어떤 요인이 기업이나 학습자에게 가장 큰 효과를 가져다주는지를 밝히기 위한 연구는 현실적으로 상당히 중요하며 의미 있는 연구로 받아들여진다. 본 연구는 멀티미디어 정보시스템을 이용한 기업체 교육훈련의 효과요인을 도출하기 위하여 문헌연구와 실증적 연구를 병행 수행하였다. 우선 멀티미디어 정보시스템에 관한 문헌연구를 통하여 멀티미디어를 이용한 교육의 22가지 효과항목을 도출하였다. 다음으로 멀티미디어 정보시스템을 갖추고 있는 국내 5대 재벌 그룹연수원의 멀티미디어 교육실에서 교육을 받은 517명의 기업체 사원들을 대상으로 약 2개월간 설문조사를 실시하여 자료를 수집하고, 통계분석 패키지를 이용하여 자료를 분석하였다. 방식을 결합한 하이브리드 형태이다.인터넷으로 주문처리하고, 신속 안전한 배달을 기대한다. 더불어 고객은 현재 자신의 물건이 배달되는 경로를 알고싶어 한다. 웹을 통해 물건을 주문한 고객이 자신이 물건의 배달 상황을 웹에서 모니터링 한다면 기업은 고객으로 공간적인 제약으로 인한 불신을 불식시키는 신뢰감을 주게 된다. 이러한 고객서비스 향상과 물류비용 절감은 사이버 쇼핑몰이 전국 어디서나 우리의 안방에서 자연스럽게 점할 수 있는 상황을 만들 것이다.SP가 도입되어, 설계업무를 지원하기위한 기본적인 시스템 구조를 구상하게 된다. 이와 함께 IT Model을 구성하게 되는데, 객체지향적 접근 방법으로 Model을 생성하고 UML(Unified Modeling Language)을 Tool로 사용한다. 단계 4)는 Software Engineering 관점으로 접근한다. 이는 최종산물이라고 볼 수 있는 설계업무 지원 시스템을 Design하는 과정으로, 시스템에 사용될 데이터를 Design하는 과정과, 데이터를 기반으로 한 기능을 Design하는 과정으로 나눈다. 이를 통해 생성된 Model에 따라 최종적으로 Coding을 통하여 실제 시스템을 구축하게 된다.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 Magnetics Society
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• v.22 no.2
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• pp.58-65
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• 2012

Since Nd-Fe-B magnet was first synthesized in 1983, many new applications have emerged in the past two decades. With regard to motor market, it will expand because of strong energy saving requirements from the automobile and electric application markets. Especially, permanent magnet motors for hybrid and electric vehicles are drawing great attention and the usage of Nd-Fe-B magnets will increase all the more hereafter. There is, however, a serious problem as motors in such eco-friendly cars are said to operate in high temperatures of about $200^{\circ}C$. Nd-Fe-B magnet has a drawback of dramatically decreasing coercive force with the rise of temperature. In order to improve this aspect. the best way is to add dysprosium (Dy) into the magnet. So, Dy has become an essential element for Nd-Fe-B high-performance magnet as it helps to maintain coercive force even at high temperatures. On the other hand, the rare earth resources in the earth crust are eccentrically-located and its majority is produced in China. There is a need to reduce its usage as, especially compared to light rare earth elements as neodymium (Nd) and samarium (Sm), heavy rare earth elements including Dy are unevenly distributed to a dramatic degree, their output low, and their prices are about 10 times that of Nd. The present article includes a summary of the trend in research and development of motors and permanent magnets to solve rare-earth resources problem.

• Journal of Intelligence and Information Systems
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• v.19 no.2
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• pp.55-71
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• 2013

The prediction model is the main factor affecting the performance of a knowledge-based system for bankruptcy prediction. Earlier studies on prediction modeling have focused on the building of a single best model using statistical and artificial intelligence techniques. However, since the mid-1980s, integration of multiple techniques (hybrid techniques) and, by extension, combinations of the outputs of several models (ensemble techniques) have, according to the experimental results, generally outperformed individual models. An ensemble is a technique that constructs a set of multiple models, combines their outputs, and produces one final prediction. The way in which the outputs of ensemble members are combined is one of the important issues affecting prediction accuracy. A variety of combination schemes have been proposed in order to improve prediction performance in ensembles. Each combination scheme has advantages and limitations, and can be influenced by domain and circumstance. Accordingly, decisions on the most appropriate combination scheme in a given domain and contingency are very difficult. This paper proposes a confidence-based selection approach as part of an ensemble bankruptcy-prediction scheme that can measure unified confidence, even if ensemble members produce different types of continuous-valued outputs. The present experimental results show that when varying the number of models to combine, according to the creation type of ensemble members, the proposed combination method offers the best performance in the ensemble having the largest number of models, even when compared with the methods most often employed in bankruptcy prediction.

• Journal of Wetlands Research
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• v.23 no.3
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• pp.242-251
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• 2021

Surface water pollution is a serious environmental problem in developing countries, like India, due to the unregulated discharge of untreated wastewater. To overcome this, the constructed wetlands (CWs) have been proven to be an efficient technology for wastewater treatment. In this study, different existing and experimental facilities were reviewed to be able to determine the current status of constructed wetlands in India. Based on the collected data from published literature, industrial wastewater contained the highest average chemical oxygen demand (COD), biochemical oxygen demand (BOD). In terms of total nitrogen (TN), Total phosphorous (TP), the lowest concentration was found on domestic wastewater. Vertical flow constructed wetlands (VFCW) and Horizontal flow constructed wetland (HFCW) were more effective in removing TSS, BOD, TP in domestic and industrial wastewater, whereas hybrid constructed wetlands (HCW) showed the highest removal for COD. The use of constructed wetlands as advanced wastewater treatment facilities in India yielded better water quality. The treatment of wastewater using constructed wetlands also enabled further reuse of wastewater for irrigation and other agricultural purposes. Overall, this study can be beneficial in evaluating and promoting the use of constructed wetlands in India.

• Journal of Korea Entertainment Industry Association
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• v.15 no.4
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• pp.383-390
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• 2021

Recently, the drone industry is rapidly expanding as it is suggested that it will be used in various fields. As the size of the drone market grows, interest in drone-related certificates is also increasing. However, the current drone-related qualification system and education system are insufficient. Thus this study, analyzed the necessity of drone training, the features of functional games, and the effectiveness of educational training using AR through related technical studies to solve the practical difficulties of drone educational training. Later, drone educational training game contents using AR were divided into practice mode and test mode based on the drone national qualification course practical test, and the result screen was displayed at the end of the curriculum so that players could learn by level and evaluate the results on their own. In addition, constructed a hybrid processing system and network and AR operation system for response rate and response speed, implemented drone training game contents utilizing AR based on the design contents. It is expected that the use of game content using AR presented in this paper for drone training will further alleviate environmental difficulties and improve the sense of immersion in play, which will lead to a more effective drone educational training experience.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.33 no.3
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• pp.239-265
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• 2022

The purpose of this study is to examine the status of RDA adoption in Korea and the perception of university librarians on RDA adoption. For this purpose, the adoption status of two libraries that adopted RDA among domestic libraries was analyzed. In addition, interviews were conducted with eight university librarians, and narrative responses related to the adoption of RDA were collected and analyzed. As a result of the interview survey, the research participants recognized that the concept of RDA is very difficult and abstract, there are few implementation cases where RDA is applied, and that it would be very difficult to adopt RDA due to the personnel and budget conditions of the local library. The RDA adoption method recognized by the research participants is to improve RDA awareness, conduct RDA education, prepare guidelines for constructing hybrid bibliographic records when RDA is adopted, operate an RDA pilot institution, and establish a performance model. In addition, research participants need coordination with companies for implementation, prefer to change a specific point in time rather than batch retroactive conversion, discover success stories, establish RDA-related online channels, build and utilize national authority DB, and use the national budget and system support. In this study, based on the research results, a plan to adopt RDA for university libraries in Korea was presented.