• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2010년도 추계학술대회 초록집
• /
• pp.75.1-75.1
• /
• 2010

This research presents a fuel cell simulator for control logic verification and operator training. Nowadays, power industries are focusing on clean energy as a response to new policy. The fuel cell can be the solution for clean energy, but operating technology is not well developed compared to other conventional power plans because of its short history. Therefore we need a simulator to verify the new control strategy and train operators, because the price of a real fuel cell system is too high and mechanically weak to be used for these kind of purposes. To develop the simulator, a 300 KW MCFC(Molten Carbonate Fuel Cell) system was modeled with stack, BOPs(pre-reformer, steam generator, etc) and mechanical components(valves, pipes, pumps, blowers, etc). The process model was integrated to emulated control system and HMI(Human Machine Interface). A static load and open loop tests were conducted for verifying the accuracy of the process model, since it is the most important part in the simulation. After verifying the process model, an automatic load change and start-up tests were conducted to verify the performance of a new control strategy(logic and functional loops).

• 대한기계학회논문집A
• /
• 제21권7호
• /
• pp.1089-1096
• /
• 1997

In this paper, Rancho Seco transient which is reported as a typical pressurized thermal shock event is postulated to be occuring in the Kori unit 1 plant, the oldest nuclear power plant in Korea. For the given material properties, transient history such as temperature and pressure, and postulated flaw, the stress distribution is obtained to calculate stress intensities for a wide range of assumed crack sizes. The stress intensities are compared with the fracture toughness, which is determined using the material properties and the distribution of the nil ductility transition temperature, to determine if cracking is expected to occur during the transient. The allowable operating year for the transient is determined and the evaluation results are discussed.

• 한국콘텐츠학회:학술대회논문집
• /
• 한국콘텐츠학회 2006년도 춘계 종합학술대회 논문집
• /
• pp.99-102
• /
• 2006

콜센터는 고객과의 상호작용이 가장 많이 일어나는 고객접점으로 인식되고 있으며, 고객만족도를 향상시키고 고객 유지율을 증가시키는 활동을 하는 기업의 제 1 관문으로서의 그 역할이 증대되고 있다. 콜센터의 서비스 품질은 기업경쟁력의 척도로서 운영기법과 경영관리에 있어서 고객과 의사소통하는 최 일선의 접점으로서 그 중요성이 점차 확대되어가고 있다. 또한 고객의 요구수준에 맞추기 위해서 서비스 품질을 향상시키는 것이야말로 경영진과 텔레마케터 모두의 당면 과제이기도 하다. 텔레마케터 교육을 위한 교육과정은 아직 확립되거나 표준화되지 않은 상태에 있다. 비록 짧은 역사를 가지고 아직 학문적 체계가 미비한 상태이지만 가능한 빨리 이에 대한 연구가 이루어져야 한다. 본 논문에서는 기존의 교육프로그램들을 분석하고, 콜센터의 의견들을 반영한 콜센터의 정형화된 텔레마케터 교육 프로그램을 개발에 관해 기술한다.

• Acta Via Serica
• /
• 제1권1호
• /
• pp.105-117
• /
• 2016

The Silk Road named by Ferdinand von Richthofen was not designated as a specific route. A lot of East-West trade routes had already existed across the continent and the geographical scope and definition of the Silk Road is still expanding. In particular, the claim that the Eastern end of the Silk Road reaches Gyeongju is an example of this expansion. Burial treasures from tombs on the Korean Peninsula have already been identified as products from the Sassanian Dynasty of Persia, and various archaeological and epical evidences support this finding. However, the specific route where these exchanges were made, around the 6th-8th centuries, has yet to be identified. Maritime as well as inland routes can easily be hypothesized. The Silk Road was largely activated by the Yam postal system with the expansion of the Mongol Empire. It not only served as an effective pathway for the Yuan to rule over the Goryeo, but also connected the Eastern end of the Silk Road to Gyeongju. This can explain the situation since the 13th century. Therefore, this paper claims that the Yeokcham system had been operating on the Korean Peninsula since the Unified Silla Kingdom, the previous period of Goryeo, or perhaps even before then. The Yeokcham should thus be regarded as a prototype of the Mongolian Yam, and the Korean peninsula should be recognized as another route which contributed specifically to the development of the Silk Road, not just as a user or a beneficiary.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2009년도 정보 및 제어 심포지움 논문집
• /
• pp.284-286
• /
• 2009

In this paper, we consider a cognitive radio system operating as secondary user. It uses an empty channel that is not currently used by primary users having the license to the channel. In the previous works, secondary user looks for an empty channel by choosing any channel in order or randomly and by sensing the channel to distinguish whether primary users are using. But if primary user is fixed type, we will find an empty channel faster than the mentioned channel selecting methods by using a method considering prior information about cases that primary user used the channel, since it is possible to analogize the channel access possibility of primary user according to regular time and position. Therefore, we propose a channel searching method based on the channel list for the purpose of reducing the channel searching time and improving throughput of secondary users. Firstly, we determine a weighting value of each channel based on the history of channel activities of primary users. This value is added to current channel state buffer and we search an empty channel from channel with smallest value to one with the biggest value. Finally, we compare the performances of the proposed method with those of the sequential channel searching and the random channel searching methods in terms of the average channel searching time and the average number of transmissions of secondary user.

• Corrosion Science and Technology
• /
• 제11권5호
• /
• pp.196-204
• /
• 2012

Corrosion failure of petrochemical facilities is one of the difficulties in maintenance, since operating conditions of crude oil production, storage, and refinement are very aggressive. UNS N08810, which has been used for crude oil transportation pipes and storage tanks in petrochemical industries, shows good resistance to general corrosion and localized corrosion in several environments. Among its environments, UNS N08810 showed better corrosion resistance in fuel gas containing sulfuric acid and phosphoric acid and sulfur. However, ductility and toughness at high temperature over about $500^{\circ}C$ were greatly reduced due to microstructural change. In general, welding process is the representative method to join the parts in industrial components. Because the alloy by welding can be sensitized and corroded, the manufacturing process should be controlled. In this work, UNS N08810 was used and heat treatment conditions including solution and stabilization treatments were controlled. Oxalic acid etch test by ASTM A262 Practice A was done to evaluate the qualitative sensitization in room temperature. Huey test by ASTM A262 Practice C was done to evaluate the intergranular corrosion rate in boiling 65% $HNO_3$ solution. Also, the microstructure by thermal history was analyzed. Experimental alloy showed high intergranular corrosion rate and its corrosion mechanism was elucidated.

• 한국문헌정보학회지
• /
• 제39권1호
• /
• pp.279-294
• /
• 2005

이 연구는 국내에서 거의 논의되지 않은 '도서관의 친구'의 운영과 활동 현황을 외국의 사례를 중심으로 조사 분석하는데 목적이 있다. '도서관의 친구'는 일반 사람들이 주축이 되어 도서관을 여러 가지 방법으로 도울 목적으로 만든 모임이다. 이 '도서관의 친구'는 근 1세기 동안 세계 각국의 여러 관종의 도서관과 긴밀한 관계를 맺어 왔다. 이 그룹은 기금모금, 자원봉사, 홍보활동, 로비 및 캠페인 그리고 지역주민 연계 등 다양한 방법으로 도서관의 운영과 서비스를 지원하고 있다. 이러한 활동 때문에 '도서관의 친구'는 최근 들어 그 중요성과 필요성이 더욱 강조되고 있고 점점 더 많은 국가의 도서관에서 만들어지고 있다. 우리 나라의 도서관들도 '도서관의 친구'를 활용하면 도서관의 운영을 개선하고 더 나은 서비스를 제공 할 수 있을 것으로 기대 된다.

• 농촌계획
• /
• 제23권1호
• /
• pp.165-174
• /
• 2017

Four requirements for the operating and supporting system for sustainable landscape management will be discussed through this paper. The requirements are based on multiple case studies on the structure and the process of development of three organizations that have been contributing to the sustainable rural landscape management in Japan since 1989. The first requirement is that the residents should recognize regional problems and voluntarily organize a group which can properly deal with the problems. Secondly, members of the organization should have a solid grasp of the goal of their activities (or founding principal of the organization) and share it among themselves. Founding principal should include the history of natural circulation system in the area, cultural features and a future plan in association with human resources. Thirdly, the administration of the organization should be separated from the founder, the residents. The administration, such as business promotion, becomes more effective when consigned to a separate entity, not to the residents. Lastly, the interaction among separate entities is crucial to promote diverse activities for the local landscape management. The administrators and experts need to cooperate to draw a precise conclusion regarding the way of interaction. These requirements drawn from the Japanese case studies should be localized to the Korean circumstances for further adoption.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2004년도 제5회 압연심포지엄 신 시장 개척을 위한 압연기술
• /
• pp.297-306
• /
• 2004

This study investigated Austenite Grain Size (AGS) distribution in Low-Speed Round-Oval Rolling. Rolling experiments were done along with the AGS numerical modeling to characterize the final AGS distribution and its kinetics behavior. For bar rolling experiment, we utilized the pilot rolling mill, operating at 34 fixed rpm, at POSCO Technical Research Laboratories. To investigate the microstructural observation, the rigid-viscoplastic finite element analysis was combined with Hodgson's AGS evolution model. To consider the transient thermal history in the integrative AGS modeling, additivity rule was introduced. The integrated analysis revealed that static or meta-dynamic recrystallization is responsible for the AGS difference in the inner or outer region of rolled bar. Comparative study showed that the current AGS modeling approach can be used to model the overall AGS distribution in bar rolling processes. For more accurate AGS prediction, the AGS modeling method should be verified under the various rolling conditions such as different rolling speeds and different deformations.

• 대한의료기공학회지
• /
• 제10권1호
• /
• pp.37-45
• /
• 2007

Benign Paroxysmal Positional Vertigo(BPPV) is a common disorder that peripheral vertigo in clinic, it is provoked Paroxysmal vertigo according to positional change. A man, aged 75, suffered from attacks of vertigo when get out of bed, He complained vertigo, nausea and walking trouble So he visited our clinic Based upon the case history and position-provoked vertigo with characteristic findings on the Dix-Hallpike maneuver, we diagnosed as BPPV. Through only Shang-San-Huang(上三黃) of Dong Shi Xue(董氏穴) acupuncture therapy symptoms were vanished completely. This study was showed effect that operating only Dong-Shi acupuncture therapy without maneuver therapy and the other therapies to patient can not tolerate the Dix-Hallpike Maneuver. We need additional researches with methodological improvement and many clinical cases.