• Structural Engineering and Mechanics
• /
• 제40권3호
• /
• pp.335-346
• /
• 2011

This paper deals with the bifurcations of non-semi-simple eigenvalues at critical point of Hopf bifurcation to understand the dynamic behavior of the system. By using the Puiseux expansion, the expression of the bifurcation of non-semi-simple eigenvalues and the corresponding topological structure in the parameter space are obtained. The zero-order approximate solutions in the vicinity of the critical points at which the multiple Hopf bifurcation may occur are developed. A numerical example, the flutter problem of an airfoil in simplified model, is given to illustrate the application of the proposed method.

• 대한수학회보
• /
• 제31권2호
• /
• pp.167-172
• /
• 1994

For a given $C^{*}$-dynamical system (A, G, .alpha.) with a G-simple $C^{*}$-algebra A (that is A has no proper .alpha.-invariant ideal) many authors have studied the simplicity of a $C^{*}$-crossed product A $x_{\alpha{r}}$ G. In [1] topological freeness of an action is shown to guarantee the simplicity of the reduced $C^{*}$-crossed product A $x_{\alpha{r}}$ G when A is G-simple. In this paper we investigate the pure infiniteness of a simple $C^{*}$-crossed product A $x_{\alpha}$ G of a purely infinite simple $C^{*}$-algebra A and a topologically free action .alpha. of a finite group G, and find a sufficient condition in terms of the action on the spectrum of the multiplier algebra M(A) of A. Showing this we also prove that some extension of a topologically free action is still topologically free.

• 한국공간정보시스템학회:학술대회논문집
• /
• 한국공간정보시스템학회 2000년도 학술회의 논문집 3권2호
• /
• pp.139-153
• /
• 2000

지리 정보 시스템을 위한 공간 데이터베이스 관리시스템간의 이질성을 최소화하고 공간 데이터의 호환성이나 상호 연동성을 높일 수 있도록 OGC에서 OpenGIS의 사양을 정의하였다. 본 연구에서는 OpenGIS에서 정의된 공간 데이터 모델을 지원하는 컴포넌트를 구현한 것이다. 즉, OpenGIS에서 요구되어진 사양에 따라 SFG (Simple Feature Geometry) 컴포넌트를 구현하였다. 본 논문에서는 컴포넌트 구현상의 발생되었던 문제점과 이 해결 방법을 제시한다. 또한 구현 도중에 발견된 OpenGIS SFG의 사양 자체의 문제점도 함께 제시한다.

• 한국전산유체공학회지
• /
• 제14권4호
• /
• pp.86-92
• /
• 2009

Nowadays, the development of microfluidic chip [i.e. biochip, micro-total analysis system ($\mu$-TAS) and LOC (lab-on-a-chip)] becomes more active, and the microchannels to deliver fluid by pressure or electroosmotic forces tend to be more complex like electronic circuits or networks. For a simple network of channels, we may calculate the pressure and the flow rate easily by using suitable formula. However, for complex network it is not handy to obtain such information with that simple way. For this reason, Graphic User Interface (GUI) program which can rapidly give required information should be necessary for microchip designers. In this paper, we present a GUI program developed in our laboratory and the simple theoretical formula used in the program. We applied our program to simple case and could get results compared well with other numerical results. Further, we applied our program to several complex cases and obtained reasonable results.

• Journal of the Korean Statistical Society
• /
• 제12권2호
• /
• pp.95-99
• /
• 1983

Limiting law for maximum queue length in G/M/1 queue system is derived. Furthermore, a simple approach using mixing sequence is also discussed.

• Bulletin of the Korean Chemical Society
• /
• 제22권11호
• /
• pp.1273-1276
• /
• 2001

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
• /
• pp.8-8
• /
• 2000

PICARD (Port-Interface Component Architecture for Real-time system Design) is a software architecture and environment, which is aimed to reduce development time and cost of real-time, control system. With PICARD, a control engineer can construct a control system software by assembling pre-built software components us ing interact ive graphical development environment. PICARD consists of PVM(Picard Virtual Machine) , a component library, and PICE(PIcard Configuration Editor). PVM is a real-time engine of the PICARD system which runs control tasks on a real-time operating system. The component library is composed of components which are called task blocks. PICE is a visual editor which can configure control tasks by creating data-flow diagrams of task blocks or Ladder diagrams for sequential logics. For the communication between PVM on a target system and PICE on a host computer, a simple protocol and tools for stub generation was dove]oped because RPC or CORBA is difficult to be applied for the embedded system. New features such as a byte-code based run time system and a simple and easy MMI builder are also introduced.

• 한국인터넷방송통신학회논문지
• /
• 제11권1호
• /
• pp.87-92
• /
• 2011

영상처리시 처리 요구 되는 영상데이터의 크기에 비례하여 시스템의 부담은 더욱 더 증가하게 된다. 특히 클라이언트로부터 전송되는 영상 데이터를 실시간으로 서버에서 분석하여 처리하는 원격 영상처리 시스템에서는 처리해야 할 데이터가 집중되는 서버 측에는 데이터의 병목현상이 발생하게 되고, 데이터의 병목현상은 시스템의 성능을 저하시킬 수 있다. 이를 해결하기 위해 여러 대의 서버를 두어 처리하는 단순 분산처리를 사용하여 해결 할 수 있으나, 이는 그만큼의 비용 부담을 가져올 수 있다. 본 논문에서는 영상 데이터 처리의 병목현상을 해결하기 위한 분산 시스템에 객체 활성화 기술을 접목시킨 새로운 형태의 분산 영상 처리를 제안하고자 한다. 제안한 방법은 영상 전처리 작업을 최적화 된 시스템에 의해 처리하게 하여 더 높은 성능을 가져올 수 있다. 또한 최적화된 서버의 오류로 인해 정상적으로 동작하지 않을 경우를 대비하여, 네트워크 내의 유휴서버를 활용하여 서비스를 제공할 수 있다.

• Nuclear Engineering and Technology
• /
• 제51권2호
• /
• pp.444-452
• /
• 2019

To assess the availability of a nuclear power plant's dynamic systems, it is necessary to consider the impact of dynamic interactions, such as components, software, and operating processes. However, there is currently no simple, easy-to-use tool for assessing the availability of these dynamic systems. The existing method, such as Markov chains, derives an accurate solution but has difficulty in modeling the system. When using conventional fault trees, the reliability of a system with dynamic characteristics cannot be evaluated accurately because the fault trees consider reliability of a specific operating configuration of the system. The dynamic reliability graph with general gates (DRGGG) allows an intuitive modeling similar to the actual system configuration, which can reduce the human errors that can occur during modeling of the target system. However, because the current DRGGG is able to evaluate the dynamic system in terms of only reliability without repair, a new evaluation method that can calculate the availability of the dynamic system with repair is proposed through this study. The proposed method extends the DRGGG by adding the repair condition to the dynamic gates. As a result of comparing the proposed method with Markov chains regarding a simple verification model, it is confirmed that the quantified value converges to the solution.

• International Journal of Automotive Technology
• /
• 제5권3호
• /
• pp.215-219
• /
• 2004

A vehicle structure needs to be more precisely analyzed because of complexities and varieties. Structural fatigue which is generated by fluctuations of stresses during the service life of a mechanical system is the primary concern in the structural design for safety. A fatigue life is difficult to obtain in structural components during the service life of mechanical systems since the fluctuating stress contributes to fatigue. This study introduces new procedures to measure the lethargy coefficient and to predict the fatigue life of a mechanical structure by using molecular dynamic simulation. A lethargy coefficient is the total defect-estimating coefficient, which was obtained by using the results of a simple tensile test in this study. With this lethargy coefficient, fatigue life was estimated. The proposed method will be useful in predicting the fatigue life of a structurally-modified vehicle design. The effectiveness of the proposed method using lethargy coefficient measurement to predict the fatigue life of a structure was examined by applying this method to predict the fatigue life of SS41 steel, used extensively as material of vehicle structures. Two types of specimen such as pre-cracked plate and simple plate is discussed. equation of fatigue life using the lethargy coefficient and failure time, both obtained from a simple tensile test, will be useful in engineering. This measurement and prediction technology will be extended for use in analysis of any geometric shapes of modified automotive structures.