• 제목/요약/키워드: large-structure driving system

검색결과 47건 처리시간 0.024초

안전중시 시스템에서 DSM 기반 인터페이스 설계를 통한 시스템 오류 감축에 관한 연구 (On Reducing Systemic Failure of Safety-Critical Systems by DSM-based Systematic Design of Interfaces)

  • 정호전;이재천
    • 대한안전경영과학회지
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    • 제17권1호
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    • pp.93-101
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    • 2015
  • The demand from customers on better products and systems seems to be ever increasing. To meet the demand, the systems are becoming more and more complicated in terms of both scale and functionality, thereby requiring enormous effort in the development. One bright spot of this trend is that such effort has been the driving forces of the remarkable advancement in modern systems development. On the other hand, safety issues appear to be critical in many large-scale systems such as transportation and weapon systems including high-speed trains, airplanes, ships, missiles/rockets launchers, and so on. Such systems turn out to be prone to a variety of faults and thus the resultant failure can cause disastrous accidents. For the reason, they can be referred to as safety-critical systems. The systems failure can be attributed to either random or systemic factors (or sometimes both). The objective of this paper is on how to reduce potential systemic failure in safety critical systems. To do so, a proper system design is pursued to minimize the risk of systemic failure. A focus is placed on the fact that complex systems have a lot of complicated interfaces among the system elements. To effectively handle the sources of hazards at the complicated interfaces and resultant failure, a method is developed by utilizing a design structure matrix. As a case study, the developed method is applied in the design of train control systems.

PZT-PZN 세라믹의 미세구조가 압전 특성 및 TCC 거동에 미치는 영향 (Effect of Microstructure on Piezoelectric Properties and TCC Behavior in PZT-PZN Ceramics)

  • 서인태;최용수;조유리;강형원;김강산;천채일;한승호
    • 한국전기전자재료학회논문지
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    • 제35권5호
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    • pp.445-451
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    • 2022
  • Ultrasonic sensor is suitable as a next-generation autonomous driving assist device because its lower price compared to that of other sensors and its sensing stability in the external environment. Although Pb(Zr, Ti)O3 (PZT)-relaxor ferroelectric system has excellent piezoelectric properties, the change in capacitance is large in the daily operating temperature range due to the low phase transition temperature. Recently, many studies have been conducted to improve the temperature stability of ferroelectric ceramics by controlling the grain size and crystal structure, so it is necessary to study the effect of the grain size on the piezoelectric properties and the temperature stability of PZT-relaxor ferroelectric system. In this study, the piezoelectric properties, phase transition temperature, and temperature coefficient of capacitance (TCC) of 0.9 Pb(Zr1-xTix)O3-0.1 Pb(Zn1/3Nb2/3)O3 (PZTx-PZN) ceramics with various grain sizes were investigated. PZTx-PZN ceramics with larger grain size showed higher piezoelectric properties and temperature stability, and are expected to be suitable for ultrasonic devices in the future.

플라즈마 디스플레이 패널을 위한 새로운 방전 논리소자에 관한 연구 (A Study on the New Discharge Logic Device for the Plasma Display Panels)

  • 염정덕;정영철
    • 조명전기설비학회논문지
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    • 제16권1호
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    • pp.13-19
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    • 2002
  • 새로운 방전 AND gate를 가지는 플라즈마 디스플레이 패널이 제안되었고 이를 검증하기 위한 구동 회로 시스템이 개발되었다. 그리고 방전 AND gate의 동작이 검증되었다. 방전 AND gate는 8$\mu\textrm{s}$의 동작속도와 20V의 동작마진을 가지고 동작하였으며 인근 주사라인의 방전을 정확히 제어할 수 있다는 것을 알았다. 이 방식은 직류 방전을 사용함으로 종래의 방전 AND gate에 비해 손쉽게 방전을 제어할 수가 있다. 더구나 AND gate의 입력방전과 출력방전이 분리되어 동작하기 때문에 디스플레이 방전이 AND gate를 통과하는 것을 방지할 수 있다. 그러므로 대화면 플라즈마 디스플레이에의 적용이 가능하고 주사방전이 화질에 영향을 주지 않으므로 명암비의 저하가 일어나지 않는다.

On the Safety and Performance Demonstration Tests of Prototype Gen-IV Sodium-Cooled Fast Reactor and Validation and Verification of Computational Codes

  • Kim, Jong-Bum;Jeong, Ji-Young;Lee, Tae-Ho;Kim, Sungkyun;Euh, Dong-Jin;Joo, Hyung-Kook
    • Nuclear Engineering and Technology
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    • 제48권5호
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    • pp.1083-1095
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    • 2016
  • The design of Prototype Gen-IV Sodium-Cooled Fast Reactor (PGSFR) has been developed and the validation and verification (V&V) activities to demonstrate the system performance and safety are in progress. In this paper, the current status of test activities is described briefly and significant results are discussed. The large-scale sodium thermal-hydraulic test program, Sodium Test Loop for Safety Simulation and Assessment-1 (STELLA-1), produced satisfactory results, which were used for the computer codes V&V, and the performance test results of the model pump in sodiumshowed good agreement with those in water. The second phase of the STELLA program with the integral effect tests facility, STELLA-2, is in the detailed design stage of the design process. The sodium thermal-hydraulic experiment loop for finned-tube sodium-to-air heat exchanger performance test, the intermediate heat exchanger test facility, and the test facility for the reactor flow distribution are underway. Flow characteristics test in subchannels of a wire-wrapped rod bundle has been carried out for safety analysis in the core and the dynamic characteristic test of upper internal structure has been performed for the seismic analysis model for the PGSFR. The performance tests for control rod assemblies (CRAs) have been conducted for control rod drive mechanism driving parts and drop tests of the CRA under scram condition were performed. Finally, three types of inspection sensors under development for the safe operation of the PGSFR were explained with significant results.

The Effect of Dielectric Thickness and Barrier Rib Height on Addressing Time of Coplanar ac PDP

  • Lee, Sung-Hyun;Kim, Young-Dae;Shin, Joong-Hong;Cho, Jung-Soo;Park, Chung-Hoo
    • Journal of KIEE
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    • 제11권1호
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    • pp.41-45
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    • 2001
  • The addressing time should be reduced by modifying cell structure and/or driving method in order to replace the dual scan system by single scan and increase the luminance in large ac plasma display panel(PDP). In this paper, the effects of the dielectric layer thickness and the barrier rib height on the addressing time of ac PDP are investigated. It is found out that the addressing time was decreased with decreasing thickness of dielectric layer on the front glass and thickness of white dielectric layer on the rear glass. The decreasing rate were 160ns/10${\mu}{\textrm}{m}$ and 270nsd/10${\mu}{\textrm}{m}$, respectively. Also in case of decreasing the height of barrier rib, addressing time was decreased at the rate of 550ns/10${\mu}m$.

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터널관리시스템의 안전운영 적정성 분석 (Adequacy Analysis of Tunnel Management System in terms of Operational Safety)

  • 박범진;노창균;문병섭
    • 한국ITS학회 논문지
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    • 제14권5호
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    • pp.1-12
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    • 2015
  • 터널은 자연훼손 최소화, 주행편의 향상과 건설장비 발전 등의 이유로 지속적으로 건설되며, 터널의 연장 또한 증가하고 있다. 하지만, 터널의 페쇄적 구조는 대형사고로 이어질 확률이 크며, 터널에서의 교통사고 건수는 예년에 비하여 대폭 증가되고 있다. 이러한 이유로 최근 터널은 터널관리시스템을 구축하여 신속한 사고처리와 방재관리에 심혈을 기울이고 있다. 이와 같은 측면에서 본 연구에서는 실제 터널관리시스템의 현황 파악, 현 시스템 진단 및 개선사항 도출을 목적으로 하고 있다. 터널관리 시스템은 실제 터널관리시스템은 운영 및 관리하는 터널관리사무소 직원이 가장 정확히 알고 있으므로 이들을 전문가로 규정하고, 전문가 설문을 통한 시스템 진단이 가능한 분석 방법을 선택하였다. 본 연구에서는 이를 고려하여 터널관리시스템을 상위요소 3개, 하위요소 16개로 계층을 나눠 터널관리사무소의 관리자 43명을 대상으로 IPA와 AHP 조사를 수행하였다. 조사결과를 활용하여 본 연구에서는 터널관리시스템의 안전 운영 적정성을 분석하였다. 분석결과 관리자들은 터널관리를 방재관리 위주로 진행하고 있어 이 부분의 하위요소들이 대부분 중요도와 만족도가 동시에 높은 것으로 분석되었다. 하지만 돌발상황 관리와 관련된 분야는 중요도와 만족도의 차이가 1.17로 가장 높으며, IPA결과를 나타내는 포트폴리오 차트에서도 2사분면에 위치한다. AHP분석결과도 방재관리의 하위분야는 대부분 고순위로 위치하였으나, 1순위는 돌발상황 관리 분야로 조사되었다. 본 연구는 현장의 실무자가 판단한 결과로 의미가 있다고 판단된다. 또한 실무자들이 개선이 필요하다고 느끼는 항목은 우선적인 개선이 이루어져야 할 것이다.

어촌지도사업의 평가 (An Evaluation on the Operating of Fisheries Extension Services)

  • 최정윤
    • 수산경영론집
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    • 제17권2호
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    • pp.65-106
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    • 1986
  • 1, The Purpose of Study This is a study on the Evaluation of the operating of Fisheries Extension Services of Korea, for performing the activities such as guiding fisheries technique as well as offering industrial information to the fishermen in fishing village. By doing so, the Fisheries Extension Sevices(FES) can materialize the continued growth of fisheries, the social and economic development of fishing village, and the increase in income by enhancing the knowledge level of Fishermen, etc. In performing fisheries policy, this activity plays a great role on the research and development activity, and it has become practical since 1976 in Korea. In order to meet immediately with the problem of fisheries technical innovation and rapid environmental changes surrounding the fisheries, the fishermen should not only enhance their scientific and comprehensive capacity in fisheries technique but abtain various effective information. Generally, as most of all the fishemen are poor in the managerial structure and scattered in fishing villages, they have little opportunity in the contact of information. As a result, it is nessessary for the FES to perform the fishing business by the extension service officials who has received special training and acquired fisheries know-how in these fields. And yet, FES is under the unfullfilled circumstance in such factors as manpower, technical know-how, equipment, and the service system etc., which is required in promoting the social, economic development of fishing village and in resolving the high technique demand of fisherman. This study on the fisheries extension services have been studied from those backgrounds. 2. Research Method The data of collecting methods which were necessary in carrying out this study was adopted by the questionaire research on the present extension service activity, through the subject of the extension services (driving agency of the work and the officials), the object(fishemen) and the 3rd observers to the extension services (the authorities concerned). The research sample was taken by the sampling extraction of total 1, 774 men from the above 3 groups. And the research was carried out from August, 1986 to October, 1986, supported from the Fisheries Extension Office (FEO) located in field during the research process. In this study, the levels of the extension operating were determined and estimated in accordance with the extension service method, morale of extension service officials and the extension service system, etc. through the collected data of the research questionaire paper. And based on this result, the essential conditions of the extension services were grasped, and also we tried to present the various activity plan necessary to promote the operating of the extension services. The questionaire research data was calculated by the computer center of National Fisheries University of Pusan, and the total result was again tried on the one demension analysis along with two dimension analysis to search out the relativity between the questionaire, and the statistical test was done $\chi$$^2$test in significance level of l~5%. 3. Contents of Study This study consists of 7 chapters and the contents are as follows : Chapter I : The object and method of the study Chapter II : The assessment and analysis of the extension services Chapter III : The contents and method of the extension services Chapter IV : Analysis of the essential conditions for the extension services Chapter V : The evaluation of activities of extension services Chapter Ⅵ : Conclusion.4. Results and RecommendationTherefore, the results of this study estimated by logical process and analysis are as follows : 1) Most of Korean fishing villages and coastal fishermen have shown much concerns about fisheries technique and social changes, thus many of them were confronted with new problems on how to adapt and to meet changes. 2) Majority of fishermen estimated FEO as an organization of specific technologies with all the thing concerning the fisheries technique in general. Therefore the fishermen wanted to utilize the FEO as an adaptable method for the modern fisheries techniques as well as the environmental changes. 3) In contrast with the fast changes of the fisheries technique, the complexity and variety of technical system and the broadness of fishing village and fishermen, it was revealed that the necessary factors such as the facilities, manpower, budget, and the level of applying techniques of the FEO located in field were highly insufficient. Accordingly, the guiding efficiency was low and the extension services did not provide full solution to the various request from fishermen. 4) It is possible to classify the activation factor for the extension service into two large dimension ; personal dimension relevant to guidance officials and work dimension relevant to the organization. And it was found that the activation level of the work dimension was far lower than the personal dimension between them. So, the activation should be done first in the dimesion to promote the activation of the extension services. 5) The extension services officials are now demoralized in general, thus it is necessary to take reality into consideration : the expense of activity, the adequate endowment of activity scope and the reasonable operation of the position class, etc to enhance its morale. However, in order to do the FES activation, first of all, the systems should be established which is lain unsettled stage until now. And there must be change in the understanding of government i.e. the fisheries extension services are the essential policy subject to build up the base of fisheries growth and modernize the fisheries management. And it should be driven positively with the recognition of the "lasting project".g project".uot;.

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