• Computers and Concrete
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• 제19권3호
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• pp.293-303
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• 2017

Maximum deflection in a beam is a serviceability design criterion and occurs generally at or close to the mid-span. This paper presents a methodology using neural networks for rapid prediction of mid-span deflections in reinforced concrete beams subjected to service load. The closed form expressions are further obtained from the trained neural networks. The closed form expressions take into account cracking in concrete at in-span and at near the interior supports and tension stiffening effect. The expressions predict the inelastic deflections (incorporating the concrete cracking) from the elastic moments and the elastic deflections (neglecting the concrete cracking). Five separate neural networks are trained since these have been postulated to represent all beams having any number of spans. The training, validating, and testing data sets for the neural networks are generated using an analytical-numerical procedure of analysis. The proposed expressions have been verified by comparison with the experimental results reported elsewhere and also by comparison with the finite element method (FEM). The proposed expressions, at minimal input data and minimal computation effort, yield results that are close to FEM results. The expressions can be used in every day design since the errors are found to be small.

• 대한화학회지
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• 제39권1호
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• pp.14-22
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• 1995

주어진 시간에 금속 고체 내부의 목표 부위에 탄성에너지를 집중시킬 수 있도록 표면에 가해주는 최적의 레이저 pulse의 형태를 디자인 하는 문제에 관하여 연구하였다. 금속고체 표면에 레이저를 쪼여주면 흡수된 광에너지가 열로 바뀌어 열팽창에 의하여 종파와 횡파가 고체 내부로 전파된다. 최소의 레이저의 세기를 사용하고 다른 부위에 영향을 최소화하면서 목표 부위에 원하는 에너지를 집중시킬 수 있는 최적의 레이저 펄스의 형태를 공액 변화 방법과 반 공간 Green 함수를 이용한 유한 요소법으로 조사하였다. 최적의 레이저 펄스로부터 원하는 시간에 목표 부위에 탄성에너지를 집중시키는 것을 보여주었고 또한 대부분의 에너지가 방향성이 큰 횡파로부터 온다는 것을 알았다.

• Journal of Power Electronics
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• 제14권5호
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• pp.908-917
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• 2014

For the purpose of designing an intrinsic safety Flyback converter with minimal output voltage ripple based on a specified output current, this paper first classified the energy transmission modes of the system into three sorts, namely, the Complete Inductor Supply Mode-CCM (CISM-CCM), the Incomplete Inductor Supply Mode-CCM (IISM-CCM) and the Incomplete Inductor Supply Mode-DCM (IISM-DCM). Then, the critical secondary self-inductance assorting the three modes are deduced and expressions of the output voltage ripples (OVR) are presented. For a Flyback converter with constant loads and switching frequency, it is shown that the output voltage ripple in the CISM-CCM is the smallest and that it has no relationship with the secondary self-inductance. Otherwise, the OVR of the other two modes are bigger than the previously mentioned one. It is concluded that the critical inductance between the CISM-CCM and the IISM-CCM is the minimal secondary self-inductance to ensure the smallest output voltage ripple. At last, a design method to guarantee the minimum OVR within the scales of the input voltage and load are analyzed, and the minimum secondary self-inductance is proposed to minimize the OVR. Simulations and experiments are given to verify the results.

• 한국통신학회논문지
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• 제30권6C호
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• pp.577-584
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• 2005

본 연구는 협대역 통신시스템을 위한 전처리기-등화기 구조의 여파기에서, 곱셈기를 사용하지 않는 최소 복잡도의 디지털 FIR 여파기를 설계하는 방법을 제안한다. 제안하는 여파기는 순환 다항식(cyclotomic polynomial, CP) 여파기와 2차 내삽 다항식(interpolated second order polynomial, ISOP) 등화기로 구성되며, 이 두 여파기가 동시에 혼합 정수 선형 계획법(mixed integer linear programming (MILP))으로 최적 설계되어 최소의 복잡도를 갖는 특성을 갖게 된다. 제안된 방식으로 설계된 여파기들은, 설계 규격을 만족하면서도 기존의 여파기에 비하여 복잡도면에서 월등히 간단함을 확인하였다.

• 신재생에너지
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• 제20권1호
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• pp.116-125
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• 2024

Ultra-low-head is an unexplored classification among the sites in which hydroelectric power can be produced. This is typically owing to the low power output and the economic value of the turbines available in this segment. A turbine capable of operating in an ultra-low-head condition without the need of a dam to produce electricity is developed in this study. A gate structure installed at a shallow water channel acting as a weir generates artificial head for the turbine mounted on the gate to produce power. The turbine and generator are designed to be compact and submersible for an efficient and silent operation. The gate angle is adjustable to operate the turbine at varying flow rates. The turbine is designed and tested using computational fluid dynamics tools prior to manufacturing and experimental studies. A parametric study of the runner blade parameters is conducted to obtain the most efficient blade design with minimal hydraulic losses. These parameters include the runner stagger and runner leading edge flow angles. The selected runner design showed improved hydraulic characteristics of the turbine to operate in an ultra-low-head site with minimal losses.

• 한국CDE학회논문집
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• 제14권3호
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• pp.207-216
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• 2009

Modern engineering design problems involve complexity of disciplinary coupling and difficulty of problem formulation. Multidisciplinary design optimization can overcome the complexity and design optimization software or frameworks can lessen the difficulty. Recently, a growing number of new multidisciplinary design optimization techniques have been proposed. However, each technique has its own pros and cons and it is hard to predict a priori which technique is more efficient than others for a specific problem. In this study, a software system has been developed to directly solve MDO problems with minimal input required. Since the system is based on MATLAB, it can exploit the optimization toolbox which is already developed and proven to be effective and robust. The framework is devised to change an MDO technique to another as the optimization goes on and it is called a reconfigurable MDO framework. Several numerical examples are shown to prove the validity of the reconfiguration idea and its effectiveness.

• 한국실내디자인학회:학술대회논문집
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• 한국실내디자인학회 2002년도 춘계학술발표대회 논문집
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• pp.58-61
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• 2002

A high-rise Mixed-use building is a multi-purpose which has commercial, business and residential uses. In Korea, after the middle of 1990's, the rate of residential parts was Increased to 90%. Now, the residential parts finally bacame mainly. And residental spaces are more important than before. Residential spaces are according to variety trends such in their areas. Some companies have several interior design trend in their building. They sometimes use the interior trend when to sell their goods(apartments) in their macketing. Modern design is presented in almost dwelling-units-types. But Classic type is presented in large-units-types. Minimal design is presented in only some middle-units-type as well as in the cases of the companies having definite interior trend. Interior design trend is one another factor in dwelling spaces design.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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• pp.107-110
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• 1996

Continuing advances in the formulation and solution of risk-sensitive control problems have reached a point at which this topic is becoming one of the more intriguing modern paradigms of feedback thought. Despite a prevailing atmosphere of close scrutiny of theoretical studies, the risk-sensitive body of knowledge is growing. Moreover, from the point of view of applications, the detailed properties of risk-sensitive design are only now beginning to be worked out. Accordingly, the time seems to be right for a survey of the historical underpinnings of the subject. This paper addresses the beginnings and the evolution, over the first quarter-century or so, and points out the close relationship of the topic with the notion of optimal cost cumulates, in particular the cost variance. It is to be expected that, in due course, some duality will appear between these notions and those in estimation and filtering. The purpose of this document is to help to lay a framework for that eventuality.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 2005년도 2005 Annual Meeting & International Symposium
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• pp.54-62
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• 2005

While genomics (the set of experimental and computational tools that allows the blueprints of life to be read) opens the doors to a more rational approach to the design and use of living cells to bring about desirable chemical transformations, genomics is, by itself, insufficient. We need tools that allow us to relate genomic and molecular information to cellular physiology and then to the response of a population of cells. We propose the development of hybrid computer cellular models. In such models genomics and chemical detail for a cellular subsystem (e.g. pathogenesis) is embedded in a coarse-grain cell model. Such a construct allows the quantitative and explicit linkage of genomic detail to cell physiology to the extracellular environment. To illustrate the principles involved we are constructing a model for a minimal cell. A minimal cell is a bacterial cell with the fewest number of genes necessary to sustain life as a free living microbe.

• 융합신호처리학회논문지
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• 제3권2호
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• pp.89-95
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• 2002

글로벌 라우팅(global routing)은 VLSI 설계 과정중의 하나로, 네트리스트의 모든 네트들을 연결하기 위하여 각 네트들을 라우팅 영역(routing area)에 할당시키는 문제이며, 글로벌 라우팅에서 최적의 해를 얻기 위해 maze routing 알고리즘, line-probe 알고리즘, shortest path 기반 알고리즘, Steiner tree 기반 알고리즘등이 이용된다. 본 논문에서는 라우팅 그래프에서 최단 경로 Steiner tree 탐색방법인 weighted network heuristic(WNH)과 이를 기반으로 하는 글로벌 라우팅 유전자 알고리즘(genetic algorithm; GA)을 제안하였으며, 제안한 방식을 시뮬레이티드 어닐링(SA) 방식과 비교, 분석하였다.