• Title, Summary, Keyword: State of Design

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Sensitivity Analysis by Parametric Study of Load Factor for a Concrete Box Girder Railway Bridge Using Limit State Design

  • Yeo, Inho;Sim, Hyung-Bo;Kim, Daehwan;Kim, Yonghan
    • International Journal of Railway
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    • v.8 no.1
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    • pp.5-9
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    • 2015
  • Reliability based limit state design method is replacing traditional deterministic designs such as allowable stress design and/or ultimate strength design methods in world trends. European design code(Eurocode) has adopted limit state design, and Korea road bridge design standard has also recently been transferred to limit state design method. In this trend, Korea railroad design standard is also preparing for adopting the same design concept. While safety factors are determined empirically in traditional design, load combinations as well as load factors are determined by solving limit state equations. General partial safety factors are evaluated by using AFORM(Advanced First Order Reliability Method) in the reliability based limit state design method. In this study sensitivity analysis is carried out for a dead load factor and a live load factor. Relative precisions of the dead load and the live load factors are discussed prior to the AFORM analysis. Furthermore the sectional forces of design and the material quantities required by two different design methods are compared for a PSC box girder railway bridge.

An analysis of the Design heating load calculation in multi-family houses (공동주택 최대난방부하 계산법의 분석)

  • 조동우
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.12 no.1
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    • pp.26-32
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    • 2000
  • Design load calculations which depend on the thermal characteristics of the building structure such as the wall, roof, and fenestration provide the basic data for selecting an HVAC system and its equipment. Most of domestic multi-family houses include a high thermal storage layer like massive concrete structure and a floor heating structure. This study is to compare the results of the design heating load between steady state and unsteady state calculation in order to comprehend the thermal storage effect in multi-family houses. The design heating load under the steady state calculation is estimated from 5.4% to 7.8% larger than that under the unsteady state in the typical floor of a multi-family house model. The design heating load considered the safety factors like a orientation and location factor also is 21.4% to 26.5% larger than that by the unsteady state calculation. So, the safety factors for use of the practicing engineer are analyzed as the main factor of a heating plant oversizing.

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Evaluation for Relative Safety of RC Slab Bridge of Applying Limit State Design Code on Korean Highway Bridge (도로교설계기준 한계상태설계법을 적용한 RC슬래브교의 상대 안전도 평가)

  • Park, Jin-Woo;Hwang, Hoon-Hee;Kang, Sin-Oh;Cho, Kyung-Sik;Park, Woo-Jin
    • Journal of the Korean Society of Safety
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    • v.28 no.5
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    • pp.41-48
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    • 2013
  • This paper is intended to provide the background information and justification for Korean highway bridge design code(limit state design)(2012). Limit state design method calculates reliability index and probability of failure through the analysis of the reliability of the experimental database. It has become possible to perform the economical and consistent design by evaluating the safety of a structure quantitatively. In this paper, we used the design specifications of RC slab bridge of superstructure form of Road Design Manual in Part 5 bridge built in highway bridge. This study conducted structural analysis using the method of frame structure theory, design and analysis of bridge by limit state design method, the design code including various standards and Load model applied Korean highway bridge design code limit state design(KHBDC;2012). As a result, it analyzed the effect of safety through comparison. Showing effect of improvement the safety factor and comparing the value of the result, it is determined to be capable of economical design and safety. Furthermore, limit state design method was able to determine many redundant force of cross-section compared with existing design method. It is determined that it can reduce the overall amount because of the reduction of the cross-section and girder depth.

The State Estimator Design for Servo system with Delayed Input (지연 입력을 가진 서보시스템의 상태 추정자 설계)

  • Shin, Doo-Jin;Kong, Jeong-Ja;Huh, Uk-Youl
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.48 no.5
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    • pp.607-614
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    • 1999
  • This paper deals with the design problem of the state estimator for servo system. The servo system has input time delay which depends on the computational time of control algorithm. The delayed input is a factor that brings out the state estimation error. So in order to reduce the state estimation error of the system, we propose a state estimator in which the delayed input of the system is considered. For this purpose, discrete time state space model is established accounting for the delayed input and a state estimator is designed based on this model. Kalman filter algorithm is employed in the design of the state estimator. The proposed estimator is used in the speed control of servo system with delayed input. Performance of the proposed state estimator is exemplified via simulations and experiments for servo system. Also, robustness of the proposed estimator to modeling error by variation of the system parameters is also shown in simulations.

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A Study on the Design Sea-state Determination Using the IFOSM Method (역 일계이차 모멘트법을 이용한 설계 해상상태의 결정에 관한 연구)

  • Lee, Jae-Ohk;Rho, Jun-Bumn
    • Journal of the Society of Naval Architects of Korea
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    • v.47 no.3
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    • pp.447-453
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    • 2010
  • Response-based approach is getting more preferred in determining the design sea-state for offshore structures because traditional environment-based approach is known to yield a much conservative design condition. This paper introduces the inverse first-order second-moment (IFOSM) method as a response-based approach, which is expected to give a more feasible design condition at the cost of reasonable number of motion analyses. The IFOSM method is based on the theory of probability and adopts an optimization scheme to determine the design point. Both the design maximum response and design sea state can be obtained straightforwardly from the optimum. The IFOSM method has been applied to a turret-moored FPSO's design problem and showed its effectiveness in practical use.

The Decoupling And Design Of Linear Multivariable Control Systems By State Variable Feedback (상태변수피이드백에 의한 선형다변수제어시스템의 분할식설계에 관한 연구)

  • 황창선
    • 전기의세계
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    • v.23 no.2
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    • pp.46-54
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    • 1974
  • The purposes of this paper are to deal with the design of m-input, m-output linear systems by the state variable feedback, and to extend the design capability of the state variable feedback design. The design requirements are decoupling and the exact realigation of desired transfer functions. Some methods are proposed to insert series compensators in the fixed plant in the cases when series compensators are needed to meet the input-output transfer matrix specification. The method for adding series compensators to the input channels of the fixed plant is shown by examples to lead both to the loss of the ability to decouple the augmented plant by the state variable feedback, and to the loss of desired zeroes. A method which avoids these two hazards is developed in which series compensators are put on the output channels of the fixed plant: it is proved that the augmented plant is F-invariant. By treating each subsystem individually, the designer can apply some of the previous developed knowledge of the state variable design of single-input, single-output systems.

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The Core Urban Design Strategies of Tall Building - Low Carbon Community

  • Liu, Enfang;Fan, Wenli;Pan, Jianing;Li, Jianqiang
    • International Journal of High-Rise Buildings
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    • v.2 no.2
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    • pp.85-91
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    • 2013
  • Tall building has some controversial aspects with low carbon city, but it is still a sensible choice for the metropolitan city. This paper aims to develop holistic urban design strategies to minimize impacts on the environment, increase energy efficiency and improve the quality of living in tall building communities by utilizing tall building characteristics. It puts forward the concept of integrated tall building-low carbon community design from the perspective of urban design, and summarizes five core strategies: Temporal state based on energy use, Complementary energy use state based on functions, Spatial state based on regional environment features, Transportation state based on low-carbon lifestyle and Waste utilization state based on tall building characteristics. It also applies the strategies to a practical project. The results show that the proposed urban design strategies are available approaches to mitigate the side effects of tall building on low carbon city.

Study on the implementation of malfunction, defect and failure reporting system to the korean indigenous aircraft (국내 개발 항공기에 대한 항공안전 고장보고 제도운용에 대한 고찰)

  • Park, Guen-Young;Yoo, Seung Woo
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.24 no.1
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    • pp.33-40
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    • 2016
  • ROK issued its first type certificate to the KC-100 airplane, Part 23 normal category, and become the State of Design (SoD) in 2013. Before this, ROK aviation regulations were focused on the operation and continued airworthiness of aircraft registered and operated in ROK that were designed and manufactured in another contracting state. Therefore the implementation of reporting system were restricted to gather the failure and service difficulty reports from the owners or operators and transmit the information to the State of Design and/or the manufacture relating to the type certificated aircraft. However, ROK, to fulfill the accountability of the State of Design, has to ensure there is a system to address the information received from the State of Registry on failure, malfunctions, defects and other occurrences that might cause adverse effects on the continuing airworthiness of the korean type certificated aircraft. This paper presents an overview of ICAO requirements for the State of Design, and current implementation of reporting system of USA and Japan and discusses the current status and further considerations on the rule-making for the malfunction, defect and failure reporting system applicable to the korean indigenous aircraft.

A state estimator design for servo system with delayed input (지연입력을 가진 서보시스템의 상태추정자 설계)

  • Kong, Jeong-Ja;Huh, Uk-Youl;Jeong, Kab-Kyun
    • Proceedings of the KIEE Conference
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    • pp.537-540
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    • 1998
  • This thesis deals with the design problem of the state estimator for digital servo system. Digital servo system has input time delay, which depends on the size of control algorithm. The delayed input is a factor that brings out the state estimation error. So, in order to reduce this state estimation error of the system, we proposes a state estimator in which the delayed input of the system is considered. At first, a discrete-time state-space model is established accounting for the delayed input. Next, the state estimator is designed based on this model. we employ Kalman filter algorithm in design of the state estimator. The performance of proposed state estimator is exemplified via some simulations and experiment for servo system. And robustness of the proposed estimator to modelling error by variation of the system parameter is also shown in these simulations.

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