• Title/Summary/Keyword: propulsion

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Entrepreneurship Education in Internet Business;Current Status & Future Direction (인터넷 창업교육 현황과 발전방안에 관한 연구)

  • Jeong, Jin-Su;Yang, Young-Seok
    • 한국벤처창업학회:학술대회논문집
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    • 2007.11a
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    • pp.143-174
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    • 2007
  • The objective of Starts-up education rears leading company that minimize a risk & connect them with successful idea. Internet Starts-up education is serviced in public & civil parts, it is insufficient to reach successful Starts-up support. This study is targeting on review the present condition of the Internet Starts-up education, research which it sees Internet Starts-up education actual condition investigation through investigation student of education satisfactorily and education contents and the plan to grope an Starts-up education progress coat problem and developmental plan it did. The current events point which has become research result escape first, age of the students of education, followed in educational background and, education motive and education experience presence education satisfactory boat song it appeared in these demand different, base grudge the form which is various it fixed and the education was demanded. Second, currently the department of pedagogy joining in establishment leader against the technical element which is advanced swip, the education reinforcement against an enterprise accomplishment ability back human factor, an enterprise propulsion environment and an enterprise item back enterprise environment element was demanded. Time after support and consulting, completion lifestyle community construction, completion lifestyle for item connection support and the trade name net after third, establishing an enterprise we the king, after toe ring back educating which carries on shoulder the importance of the civil official was embossed. The study which it sees led and like this investigation analysis the education progress for the successful support of the Internet Starts-up and time after connection setup construction it led and the plan which it will put out advancement of Starts-up education and it groped.

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A Study of School program in the Case of Library and Information Science in Korea (한국문헌정보학의 학부제 도입에 관한 연구)

  • Koo Bon-young
    • Journal of the Korean Society for Library and Information Science
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    • v.30 no.2
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    • pp.3-50
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    • 1996
  • At present, Korean universities and colleges are confronted with a strong challenge, within and without, demanding a drastic change or innovation of university education. Discussion on the propulsion of the School Program is now under way as one of the means to reform the university education With such a background in mind, we have considered what should be the desirable course of Library and Information Science in Korea. We have considered the characteristic features and roles of library and information professionals to cope with the now approaching information society and the changing conditons of educational environment We have collected the pros and cons among professors of tile School Program, and investigated the curricula of the three universities which are at present practicing the School Program. Of the 139 professors to whom we have sent the questionnaries, $92(66\%)$ responded, of which the pros were 42 and the cons were 45. The model plan for the School Program is 'departmental school program' $(44\%)$, which purports to adopt 'departmental school program', with the curricula and material resources being utilized in common, or to adopt joint-appointment system with the common utilization of teaching materials and the introduction of a limited dual major system. The argument against introduction the School Program was that because of the peculiar nature of the discipline itself, Library and Information Science can not be merged with any other discipline.

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Fracture Characteristics of C/SiC Composites for Rocket Nozzle at Elevated Temperature (로켓 노즐목 소재 C/SiC 복합재 고온 파괴 특성)

  • Yoon, Dong Hyun;Lee, Jeong Won;Kim, Jae Hoon;Sihn, Ihn Cheol;Lim, Byung Joo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.40 no.11
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    • pp.927-933
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    • 2016
  • In a solid propulsion system, the rocket nozzle is exposed to high temperature combustion gas. Hence, choosing an appropriate material that could demonstrate adequate performance at high temperature is important. As advanced materials, carbon/silicon carbide composites (C/SiC) have been studied with the aim of using them for the rocket nozzle throat. However, when compared with typical structural materials, C/SiC composites are relatively weak in terms of both strength and toughness, owing to their quasi-brittle behavior and oxidation at high temperatures. Therefore, it is important to evaluate the thermal and mechanical properties of this material before using it in this application. This study presents an experimental method to investigate the fracture behavior of C/SiC composite material manufactured using liquid silicon infiltration (LSI) method at elevated temperatures. In particular, the effects of major parameters, such as temperature, loading, oxidation conditions, and fiber direction on strength and fracture characteristics were investigated. Fractography analysis of the fractured specimens was performed using an SEM.

Mission Analysis Involving Hall Thruster for On-Orbit Servicing (궤도상 유지보수를 위한 홀추력기 임무해석)

  • Kwon, Kybeom
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.48 no.10
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    • pp.791-799
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    • 2020
  • Launched in October 2019, Northrop Grumman's MEV-1 was the world's first unmanned mission demonstrating the practical feasibility of on-orbit servicing. Although the concept of on-orbit servicing was proposed several decades ago, it has been developed to various mission concepts providing services such as orbit change, station keeping, propellant and equipment supply, upgrade, repair, on-orbit assembly and production, and space debris removal. The historical success of MEV-1 is expected to expand the market of on-orbit servicing for government agencies and commercial sectors worldwide. The on-orbit servicing essentially requires the utilization of a highly propellant efficient electric propulsion system due to the nature of the mission. In this study, the space mission analysis for a simple on-orbit mission involving Hall thruster is conducted, which is life extension mission for geostationary orbit satellites. In order to analyze the mission, design space exploration for various Hall thruster design variable combinations is performed. The values of design variables and operational parameters of Hall thruster suitable for the mission are proposed through design space analysis and optimization, and mission performance is derived. In addition, the direction of further improvement for the current on-orbit mission analysis process and space mission analysis involving Hall thruster is reviewed.

A study on the EMI in special power distribution zone on ship (선내 특별 전원 분배구역의 EMI에 관한 연구)

  • Park, Jong-Sung;Choi, Gi-Do;Kim, Jong-Woo;Cho, Hyung-Rae
    • Journal of Advanced Marine Engineering and Technology
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    • v.38 no.6
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    • pp.730-736
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    • 2014
  • Test standards for electrical and electronic equipment required for ship operations is applying the IEC-60533 standard. However, although a test procedure and a specified regulation are clearly defined in the deck and bridge zone and general power distribution zone, they are not regulated in the special power distribution zone with ship propulsion system. For these reasons, the costs for additional research and development have been invested. In this paper, we was measured power noise in a special power distribution zone in ship and we were compared and analyzed values measured. The actual experiments are performed on the ship of Korea Maritime and Ocean University. As a result, the acquired data on Hanbada shows that loop antenna with low frequency band(160kHz) and ultra log antenna with high frequency band(1.97GHz)occur about 6-8dB differences and about 8.7 difference respectively. Also, the acquired data on Hannara shows that each loop antenna of 1MHz, 11MHz, and 25MHz occurs about 7dB difference about 4-5dB differences respectively. so standard of Special distribution zone must be specified by comparative analysis of data obtained by the experiment more.

A study on vibration control of the engine body for a large scale diesel engine using the semi-active controlled hydraulic type of top bracing (준능동형 유압식 톱브레이싱을 이용한 선박용 저속 2행정 디젤엔진의 본체 진동제어)

  • Lee, Moon-Seek;Kim, Yang-Gon;Hwang, Sang-Jae;Lee, Don-Chool;Kim, Ue-Kan
    • Journal of Advanced Marine Engineering and Technology
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    • v.38 no.6
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    • pp.632-638
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    • 2014
  • Nowadays, as part of an effort to increase the efficiency of propulsion shafting system, the revolution of the main diesel engine in CMCR(Contract Maximum Continuous Rating) is reduced whereas the stiffness of hull structure supporting the main diesel engine is relatively flexible. However, vibration problems related with resonant response of main diesel engine are increasing although top bracing is installed between the main diesel engine and the hull structures to increase natural frequency of engine body above CMCR to avoid resonant phenomenon. In this study, the dynamic characteristic of top bracing is reviewed by analyzing measuring results of general cargo ships which apply the hydraulic type instead of the friction type to control the natural frequency and the vibration of the engine body. Moreover, considering the vibration characteristic of the engine body and the hydraulic type of the top bracing by varying the number of top bracing, authors suggest the more effective way to control the vibration of the engine body despite of lower stiffness of the hull structure than in the past when the hydraulic type of top bracing is used.

A Study on Information Breakdown through the Analysis of Industrial Engineering EPC Business Process (산업설비 EPC 업무 분석을 통한 정보 분류 내역에 관한 연구)

  • Cho, Hang-Min;Song, Young-Woong;Choi, Yoon-Ki
    • Proceedings of the Korean Institute Of Construction Engineering and Management
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    • 2006.11a
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    • pp.167-172
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    • 2006
  • It follows recently in an order augmentation of overseas construction market plant field and the project of oil gas field is increasing. Consequently, the hazard which secures the competitive power of the overseas plant enterprise of the domestic building industry enterprises the technical competitiveness security which stands, productivity improvement and strategy management propulsion back positive disposal plan establishment are demanded. Even from in that oil gas field of overseas plant enterprise for an industrial competitive power improvement the application of EPC circulation information which relates with a project accomplishment is more demanded, the EPC phased star efficiently it manages the circulation information contents which occurs from the business which is various it is not presented it cannot there is a contents classification system for. If with him about lower the draft the problem point of information omission back of occurrence and business subject for of the fringe land and duplication business occurs, about lower the productivity decrease actual condition is appearing with such problem point. The research which it sees consequently in order to improve the use characteristic of the augmentation of practical application of the contents management system of oil gas field and building industry information civil official establishhes the contents management system the BPM for (Business Process Management) to present the contents classification system of base, it does to sleep. The part of Business Process materiality the knowledge which is demanded, contents information and system anger it analyzes system anger of industrial equipment circulation information it takes a triangular position and to sleep it does.

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Process Model for 6 Sigma(${\sigma}$) in Construction Management(CM) (건설사업관리(CM)에서의 6시그마(${\sigma}$) 적용 조건 분석을 통한 추진 모델 구축)

  • Kim, Chan-Gyo;Lee, Jea-Sauk;Chun, Jae-Youl
    • Proceedings of the Korean Institute Of Construction Engineering and Management
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    • 2006.11a
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    • pp.478-482
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    • 2006
  • The domestic enterprises in order to secure the freshness location of market from the international competition which is keen are propelling a price and a quality high position strategy steadily. It is put in competitive situation with the overseas enterprises and even from construction industry it follows in construction market opening and there is not another idea to the research the management strategies, directions and focus competitive elements of the enterprise against, what it sees consequently and to rise to the priority where the competitive power reinforcement of the enterprise is important, it becomes. Competitive power of like this enterprise for a reinforcement the technique which induces a big interest 6 Sigma is technique from the many companies. 6 sigma preceding researches of manufacturing and service industry the fact that it is accomplished with the object which will carry most. The research which relates with construction industry is staying to an introduction of 6 sigma the investigation phase, the actual introduction introduces and "S" construction there is not only a possibility against the application result of having a limit because it is applying. It is like that but like referring to a minute description for the international competitive power security which it follows in the change which market environment is sudden 6 sigma the introduction will judge, indispensability development of the logical propriety against hereupon and it will reach and it verifies the question investigation for to lead, 6 sigma of the construction companies it confirms the application possibility and presents the propulsion model as 6 sigma the fact that overcoming the limit characteristic of that introduction application as objective of sample research means it will do.

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A study on the wire reduction design and effect analysis for the train vehicle line (화물열차 분산제어시스템 개발에 관한 연구)

  • Lee, Kangmi;Lee, Jaeho;Yoon, Yong-Ki
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.12
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    • pp.778-784
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    • 2017
  • In this paper, we propose wired and wireless distributed control systems designed to improve the freight logistics efficiency and verify wired distributed control systems. The verification condition required that 50 cargo vehicles be connected and operated to travel 21 km from Busan Sinhang station to Jinlye Station at an average speed of about 100km/h. The verification results show that the traction output and braking output of the control and controlled cars are dispersed by the wired distributed control system. The application is expected to more than double the efficiency of the logistics compared to the existing freight transportation system. However, in the case of the wired distributed control system, cable installation and maintenance are difficult, and it is impossible to change the combination of freight vehicles. Through the verification of the wired distributed control system, the applicability of distributed control systems to freight vehicles in Korea was confirmed and the system was further developed to produce a wireless distributed control system. In order to apply the wireless distributed control system, a propagation environment analysis for the ISM band was performed in the testbed and, as a result, it was confirmed that Wifi technology using the ISM band could be utilized. In order to use the WDP (Wireless Distributed Power) devices newly installed in the target vehicles, the transmission / reception control signals associated with the propulsion / braking / total control devices are defined. In the case of wireless distributed control systems, the convenience of their application and operation is guaranteed, but reliability and emergency safety measures should because of the dependence of the control of the vehicle on radio signals.

A Study on Flexibility Acquisition Method for VLCC Shaft System (VLCC 축계 시스템의 유연성 확보 방안에 관한 연구)

  • Shin, Sang-Hoon;Ko, Dae-Eun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.12
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    • pp.135-139
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    • 2017
  • The main reason for heat accidents occurring at the after stern tube bearing (STB) is excessive local pressure caused by the deflection of the propulsion shaft due to propeller loads. The probability of a heat accident is increased by the low flexibility of the shaft system in very large crude oil carriers (VLCCs) as the engine power and shaft diameter increase and the distance decreases between the forward and after STBs. This study proposed shaft system with only an after STB and no forward STB for a flexibility acquisition method for a VLCC shaft system under hull deformation. A Hertzian contact condition was applied, which assumes a half-elliptical pressure distribution along the contact width for the calculation of the local squeeze pressure. The propeller loads, heat effect, and hull deflection under engine operating conditions are also considered. The results show that the required design criteria were satisfied by building a partial slope at the white metal, which is the material at the axial contact side in the after STB. This system could reduce building cost by simplification of the shaft system.