• Title/Summary/Keyword: Physical modeling

Search Result 1,342, Processing Time 0.032 seconds

METHOD FOR THE ANALYSIS OF TEMPORAL CHANGE OF PHYSICAL STRUCTURE IN THE INSTRUMENTATION AND CONTROL LIFE-CYCLE

  • Goring, Markus;Fay, Alexander
    • Nuclear Engineering and Technology
    • /
    • v.45 no.5
    • /
    • pp.653-664
    • /
    • 2013
  • The design of computer-based instrumentation and control (I&C) systems is determined by the allocation of I&C functions to I&C systems and components. Due to the characteristics of computer-based technology, component failures can negatively affect several I&C functions, so that the reliability proof of the I&C systems requires the accomplishment of I&C system design analyses throughout the I&C life-cycle. On one hand, this paper proposes the restructuring of the sequential IEC 61513 I&C life-cycle according to the V-model, so as to adequately integrate the concept of verification and validation. On the other hand, based on a metamodel for the modeling of I&C systems, this paper introduces a method for the modeling and analysis of the effects with respect to the superposition of failure combinations and event sequences on the I&C system design, i.e. the temporal change of physical structure is analyzed. In the first step, the method is concerned with the modeling of the I&C systems. In the second step, the method considers the analysis of temporal change of physical structure, which integrates the concepts of the diversity and defense-in-depth analysis, fault tree analysis, event tree analysis, and failure mode and effects analysis.

An ETRI CPS Modeling Language for Specifying Hybrid Systems (하이브리드 시스템을 명세하기 위한 ETRI CPS 모델링 언어)

  • Yoon, Sanghyun;Chun, In-geol;Kim, Won-Tae;Jo, Jaeyeon;Yoo, Junbeom
    • Journal of KIISE
    • /
    • v.42 no.7
    • /
    • pp.823-833
    • /
    • 2015
  • Hybrid system is a dynamic system that is composed of both a continuous and discrete system, suitable for automobile, avionic and defense systems. Various modeling languages and their supporting tools have been proposed and used in the hybrid system. The languages and tools have specific characteristics for their purpose. Electronics and Telecommunications Research Institute (ETRI) proposed a hybrid system modeling language, ECML (ETRI CPS Modeling Language). ECML extends DEV&DESS (Differential Event and Differential Equation Specified System) formalism with consideration of CPS (Cyber-Physical System), which supports modeling and simulation. In this paper, we introduce ECML and suggest a formal definition. The case study specifies a simple vehicle model using the suggested formal definition.

The use of generalized functions modeling the concentrated loads on Timoshenko beams

  • Falsone, Giovanni
    • Structural Engineering and Mechanics
    • /
    • v.67 no.4
    • /
    • pp.385-390
    • /
    • 2018
  • An incongruity is underlined about the analysis of Timoshenko beams subjected to concentrated loads modelled through the use of generalized functions. While for Euler-Bernoulli beams this modeling always leads to effective results, on the contrary, the contemporary assumptions of concentrated external moment, interpreted as a generalized function (doublet), and of shear deformation determine inconsistent discontinuities in the deflection laws. A physical/theoretical explanation of this not-neglecting incongruity is given in the text.

A modeling on the physical suitability of office chairs (사무용 의자의 물리적 적합도 모델링 개발)

  • 박수찬;신미경;최경주;김진호;윤지은
    • Proceedings of the Korean Society for Emotion and Sensibility Conference
    • /
    • 2000.04a
    • /
    • pp.81-85
    • /
    • 2000
  • The present study investigated the processes of selecting and modeling of design variables based on HIEs for developing the evaluational model on the physical suitability of office chairs. Evaluational model can be used for development of the new products or improvement of the old products. For the best utilization of the evaluational model, the process of scrutinizing the variables and the complex interactions among the variables is indispensible. Also, for this, it is necessary to select only the right HIEs which influence the physical suitability of products greatly.The present study suggested analytical processes for making the evaluational model on the physical suitability (Comfortability, Suitability, Stability, Adjustability, Clearance) of office chairs.

  • PDF

Towards A Better Understanding of Space Debris Environment

  • Hanada, Toshiya
    • International Journal of Aerospace System Engineering
    • /
    • v.3 no.1
    • /
    • pp.5-9
    • /
    • 2016
  • This paper briefly introduces efforts into space debris modeling towards a better understanding of space debris environment. Space debris modeling mainly consists of debris generation and orbit propagation. Debris generation can characterize and predict physical properties of fragments originating from explosions or collisions. Orbit propagation can characterize, track, and predict the behavior of individual or groups of space objects. Therefore, space debris modeling can build evolutionary models as essential tools to predict the stability of the future space debris populations. Space debris modeling is also useful and effective to improve the efficiency of measurements to be aware of the present environment.

Active Linear Modeling of Cochlear Biomechanics Using Hspice

  • Jarng Soon Suck;Kwon You Jung
    • The Journal of the Acoustical Society of Korea
    • /
    • v.24 no.3E
    • /
    • pp.77-86
    • /
    • 2005
  • This paper shows one and two dimensional active linear modeling of cochlear biomechanics using Hspice. The advantage of the Hspice modeling is that the cochlear biomechanics may be implemented into an analog Ie chip. This paper explains in detail how to transform the physical cochlear biomechanics to the electrical circuit model and how to represent the circuit in Hspice code. There are some circuit design rules to make the Hspice code to be executed properly.

Modeling System for Unsteady Flow Simulations in Drainage Channel Networks of Paddy Field Districts (논 지구의 배수로 부정류 흐름 모의를 위한 모델링 시스템)

  • Kang, Min Goo
    • Journal of The Korean Society of Agricultural Engineers
    • /
    • v.56 no.2
    • /
    • pp.1-9
    • /
    • 2014
  • A modeling system is constructed by integrating an one-dimensional unsteady flow simulation model and a hydrologic model to simulate flood flows in drainage channel networks of paddy field districts. The modeling system's applicability is validated by simulating flood discharges from a paddy field district, which consists of nine paddy fields and one drainage channel. The simulation results are in good agreement with the observed. Particularly, in the verification stage, the relative errors of peak flows and peak depths between the observed and simulated hydrographs range 8.96 to 10.26 % and -10.26 to 2.97 %, respectively. The modeling system's capability is compared with that of a water balance equation-based model; it is revealed that the modeling system's accuracy is superior to the other model. In addition, the simulations of flood discharges from large-sized paddy fields through drainage channels show that the flood discharge patterns are affected by drainage outlet management for paddy fields and physical characteristics of the drainage channels. Finally, it is concluded that to efficiently design drainage channel networks, it is necessary to analyze the results from simulating flood discharges of the drainage channel networks according to their physical characteristics and connectivities.

Understanding of dynamic system properties in the frequency domain using bond graphs (본드선도를 이용한 동적시스템의 주파수역 특성이해)

  • Park, Jeon-Soo;Kim, Jong-Shik
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.22 no.4
    • /
    • pp.801-810
    • /
    • 1998
  • Modeling and analysis of dynamic systems generally demand their resutls to be interpreted each other with a physical sense. It sometimes requires that there should exist a unified tool in the treatment of dynamic systems which can be applied to both their modeling and analysis equally. This paper shows how models just after the progress of modeling via bond graph standards are converted to ones which are appropriate for analyzing a dynamic system in the frequency domain. Four bond graph prototypes are introduced to obtain frequency properties of dynamic systems such as zero stability, relative order, zero and pole dynamics, etc. directly from bond graphs, and the method are proposed which reduces nearly all models of bond graph standards to one of the prototypes without any change of physical similarity. This procedure as a tool for the structural reduction of bond graphs and finding frequency properties of a dynamic system is further investigated to survey its effectiveness through an example.