• 제목/요약/키워드: Technical requirements

검색결과 845건 처리시간 0.032초

Excitation Response Estimation of Polar Class Vessel Propulsion Shafting System

  • Barro, Ronald D.;Lee, Don-Chool
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2011년도 춘계학술대회 논문집
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    • pp.463-468
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    • 2011
  • The prospect of Arctic trade transportation opening on a year-round basis creates a vast opportunity of exploring untapped resources and shortened navigational routes. However, the environment's remoteness and lack of technical experiences remains a big challenge for the maritime industry. With this, engine designers and makers are continually investigating, specifically optimizing propulsion shafting system design, to meet the environmental and technical challenges of the region. Further, classification societies recognize the need to upgrade the Unified Rules concerning elements to meet current Polar requirements. Hence in this paper, excitation torque calculation on Polar class vessels propulsion shafting system will be reviewed. The propeller - ice interaction load effect, which is a main consideration of excitation source of Polar Class propulsion shafting system, on shaft design calculation will be analyzed.

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양이온성 구아 검과 콜로이달 실리카를 이용한 보류시스템의 응집 및 보류 현상 (Flocculation and Retention Phenomena of Microparticle Retention Systems Based on Cationic Guar Gums and Colloidal Silicas)

  • 함충현;이학래
    • 펄프종이기술
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    • 제33권4호
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    • pp.1-6
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    • 2001
  • Today's paper industry tries to use greater amount of high yield pulp and recycled fiber and to close mill water system, which results in higher fines content and buildup of organic and inorganic contaminants in white water system. Researches are being focused to develop chemical additives that provide good retention and drainage in a closed papermaking system. A microparticle retention system consisted of cationic guar gum and anionic colloidal silica so has been developed to meet the requirements for improving machine speed and product quality. The objective of this investigation was to determine the effects of the degree of cationic guar gums, charge density and structure of anionic colloidal silica sols, and the degree of system closure on the performances of this microparticle retention system. Cationic guar gums and anionic colloidal silica sols with higher charge densities showed better retention performance. Particularly, wider maximum in retention was obtained when structure colloidal silica was used suggesting as mechanism of microparticle bridging is functioning in this system.

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Propagation Measurements and Estimation of Channel Propagation Models in Urban Environment

  • Zakaria, Yahia;Ivanek, Lubomir;Glesk, Ivan
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제11권5호
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    • pp.2453-2467
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    • 2017
  • Wireless communication is a telecommunication technology, which enables wireless transmission between the portable devices to provide wireless access in all types of environments. In this research, the measurements and various empirical models are analysed and compared in order to find out a suitable propagation model to provide guidelines for cell planning of wireless communication systems. The measured data was taken in urban region with low vegetation and some trees at 900 MHz frequency band. Path loss models are useful planning tools, which permit the designers of cellular communication to obtain optimal levels for the base station deployment and meeting the expected service level requirements. Outcomes show that these empirical models tend to overestimate the propagation loss. As one of the key outputs, it was observed that the calculations of Weissberger model fit with the measured data in urban environment.

초고압 송전선로의 최적 격상전압 선정에 관한 연구-리비아국 사례 (A STUDY ON OPTIMAL UPGRADING VOLTAGE OF EHV GRID NETWORK-LYBIAN CASE)

  • 김봉희
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1997년도 하계학술대회 논문집 D
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    • pp.1041-1043
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    • 1997
  • When a new transmission line is planned to construct, the system voltage and the conductor size of the transmission line should be decided by both economical and technical point of view. This paper presents a methodology to determine the optimal voltage for upgrading the transmission system voltage of existing the extra high voltage grid network by meeting the requirements of the transmission cost minimization as well as technical constraints of thermal limit and stability limit in the transmission line. As a case study, calculated are optimal voltages versus distance and capacity of a practically applicable transmission line with 4 bundles 2 circuits. By this study 400kV was selected as the next higher voltage for the existing 220kV Libyan grid network.

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Monotonic and cyclic flexural tests on lightweight aggregate concrete beams

  • Badogiannis, E.G.;Kotsovos, M.D.
    • Earthquakes and Structures
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    • 제6권3호
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    • pp.317-334
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    • 2014
  • The work is concerned with an investigation of the advantages stemming from the use of lightweight aggregate concrete in earthquake-resistant reinforced concrete construction. As the aseismic clauses of current codes make no reference to lightweight aggregate concrete beams made of lightweight aggregate concrete but designed in accordance with the code specifications for normal weight aggregate concrete, together with beams made from the latter material, are tested under load mimicking seismic action. The results obtained show that beam behaviour is essentially independent of the design method adopted, with the use of lightweight aggregate concrete being found to slightly improve the post-peak structural behaviour. When considering the significant reduction in deadweight resulting from the use of lightweight aggregate concrete, the results demonstrate that the use of this material will lead to significant savings without compromising the structural performance requirements of current codes.

NUCLEAR REGULATORY RESEARCH IN KOREA: ACHIEVEMENTS AND FUTURE DIRECTION

  • Ryu, Yong-Ho
    • Nuclear Engineering and Technology
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    • 제41권4호
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    • pp.403-412
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    • 2009
  • For efficient and effective nuclear regulation, regulatory organizations must establish consistent and rigorous regulatory positions on safety matters. These positions should be based on high technical expertise and relevant ordinances, standards, and guidelines reflecting policy changes governing nuclear regulations. The Korea Institute of Nuclear Safety, a regulatory expert organization in Korea, has developed regulatory requirements, guidelines and analytical tools that provide regulatory technical bases for ensuring nuclear safety. The nuclear regulatory research also contributes to regulatory decision making by providing resolution for current and future safety issues. In this article, we introduce nuclear regulatory research and its main achievements in the past 10 years. Also, suggested here are future directions of nuclear regulatory research.

한국형 초고속 전철의 연구개발 추진전략 (The Development Strategies of Very High Speed Train in Korea)

  • 김용주;강도현;황돈하
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1997년도 하계학술대회 논문집 A
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    • pp.352-357
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    • 1997
  • The development of very high speed train system is a complex series of interrelated tasks, many of which have some degree of uncertainty associated with the successful outcome. Successful projects recognize and provide for the major uncertainties and technical unknowns with specific development strategies. The development strategies described in this paper incorporated the experiences of the advanced countries in high speed train technologies, the current technical status of Korean industries and the operating requirements of Korean High Speed Railway.

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이동통신기반 Industrial IoT 기술 동향 (Technical Trend and Challenging Issues for Cellular-Based Industrial IoT)

  • 김원익;김은아;고영조;송재수;윤찬호;문성현;김철순;백승권
    • 전자통신동향분석
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    • 제33권5호
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    • pp.51-63
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    • 2018
  • Mobile cellular technology is evolving to accommodate a variety of vertical services, expanding the application from human-to-human communication to the Internet of Things(IoT). In particular, the fourth industrial revolution, bringing in a new vision in future smart factory, necessitates a new paradigm shift in wireless communication. Low latency and high reliability is a key issue in wireless applications for industrial IoT such as factory automation. In this paper, we review the recent progress in 5G URLLC (Ultra-Reliable Low Latency Communication) and discuss use cases, requirements, challenging technical issues, and potential solutions to support wireless factory automation such as discrete automation and process automation.

연안어선어업의 생산함수추정 (An Estimation of production Function in the Coastal Fishing)

  • 김기수;강용주
    • 수산경영론집
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    • 제24권2호
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    • pp.69-82
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    • 1993
  • The purpose of this paper is to estimate production function in the coastal fishing, especially long bag set net fishing and trap fishing using Cobb-Douglas production function with the three main variables: fishing quantity per tonage(WQFP), the number of working persons per tonage(WEMP), and the number of utilized fishing equipments per tonage(WEQU). The statistical results of such estimation reveal that fishing quantity per tonage can be expressed as a function of the number of working persons per tonage and the number of utilized fishing equipments per tonage. The estimated coefficients of WEMP and WEQU are statistically significant and also satisfy the requirements of Cobb-Douglas production function. This study also estimates marginal rate of technical substitution of labor in terms of capital (MRT $S_{LK}$ )in each long bag set net fishing and trap fishing. The resuits of this study show us that trap fishing has the technical characteristic of constant returns to scale(CRS) but long bag net fishing has that of decreassing returns to scale(DRS).

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학교 정보화교육 실태조사 및 개선방안에 관한 연구 (Research of Requirements Analysis and Survey of Actual Condition about Information Education of Technical High School)

  • 장기진;최덕현
    • 디지털융복합연구
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    • 제2권1호
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    • pp.161-175
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    • 2004
  • In this paper we present a review of school information education about technical high school in domestic. The review is based on an extensive research in the practical literature. Business of various forms such as industry, education, and medium is appearing by supply of Internet of all the world. The Information Technology market is developing by leaps and bounds among them, but suitable school information education disgrace and improvement plan were not readied in domestic Information Technology and communication situation. Therefore, this paper?wishes to satisfy purpose by school information education improvement plan and manpower practical conditions about ERP education. So that, is used to accelerate medium and small enterprises information through qualitative, quantitative valuation of medium and small enterprises information manpower supply and demand as well as domestic school information.

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