• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.21 no.3
• /
• pp.233-238
• /
• 2008

In this paper, a shape design optimization method for linearly elastic problems is developed using isogeometric approach. In many design optimization problems for practical engineering models, initial raw data usually come from a CAD modeler. Then, designers should convert the CAD data into finite element mesh data since most of conventional design optimization tools are based on finite element analysis. During this conversion, there are some numerical errors due to geometric approximation, which causes accuracy problems in response as well as design sensitivity analyses. As a remedy for this phenomenon, the isogeometric analysis method can be one of the promising approaches for the shape design optimization. The main idea of isogeometric approach is that the basis functions used in analysis is exactly the same as the ones representing the geometry. This geometrically exact model can be used in the shape sensitivity analysis and design optimization as well. Therefore the shape design sensitivity with high accuracy can be obtained, which is very essential for a gradient-based optimization. Through numerical examples, it is verified that the shape design optimization based on an isogeometic approach works well.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.31 no.5
• /
• pp.275-282
• /
• 2018

Using isogeometric analysis(IGA) gives more accurate results for higher order mode in eigenvalue problem than using the finite element method(FEM). This is because the FEM has $C^0$ continuity between elements, whereas IGA guarantee $C^{P-1}$ between elements for p-th order basis functions. In this paper, a mode based reduced model is constructed by using IGA and dynamic behavior analysis is performed using this advantage. Craig-Bampton(CB) method is applied to construct the reduced model. Several numerical examples were performed to compare the eigenvalue analysis results for various order of element basis function by applying the IGA and FEM to simple rod analysis. We have confirmed that numerical error increases in the higher order mode as the continuity between elements decreases in the IGA by allowing internal knots multiplicity. The accuracy of the solution can be improved by using the IGA with high inter-element continuity when high-frequency external force acts on the reduced model for dynamic behavior analysis.

• 주택과사람들
• /
• no.56 s.73
• /
• pp.39-44
• /
• 1996

오는 6월 30일이면 명의신탁부동산(95.6.30 이전 명의신탁)에 대한 실명전환 유예기간이 끝난다. 명의신탁부동산이란 다른 사람의 명의를 빌려 등기한 부동산을 말하는 것으로 6월 30일까지 실명으로 등기를 하거나 매각처분 또는 성업공사에 매각을 의뢰해야 하는데 이를 위반 시에는 부동산가액의 $30\%$에 해당하는 과징금이 부과되고, 명의신탁약정이 무효가 되어 법적인 보호를 받지 못하게 된다. 실명전환 방법 및 구비서류 등에 대해 알아본다.

• 주택과사람들
• /
• s.194
• /
• pp.76-77
• /
• 2006

토지 시장 침체의 골이 깊어지고 있다. 새로 개정된 부동산등기법이 시행돼 실거래가 등기부기재가 의무화되면서 토지 시장 침체가 가속화되고 있다. 내년부터는 부재 지주에 대한 양도세가 현행 9~36%에서 60%로 급등하기 때문에 토지 시장이 장기 침체에 빠질 수 있다고 전문가들은 지적한다. 부동산 시장 침체 속 토지 시장의 현장을 돌아보았다.

• The Journal of the Korea Contents Association
• /
• v.9 no.7
• /
• pp.325-332
• /
• 2009

The Korean real estate transaction makes a contract after the buying and selling person concerned agreed a business condition. As for vendee, business consists of the method that I issue documents before provision and money left over provision and the registration at the same time, and register a contract deposit in vendor. However, it latent for the real estate transaction various accidents such as fraud from a contract day to time to finish a real estate registration transfer, embezzlement, double contract by the breach of trust. Nevertheless vendee comes to match vendor by an asymmetry of the information one-sidedly to the front completing a registration transfer. I may prevent stellionate by the breach of trust of vendor if I use an ESCROW system in such a responsibility blank state.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2010.04a
• /
• pp.512-515
• /
• 2010

본 논문에서는 등기하 해석법을 이용하여 설계의존형 하중조건을 갖는 구조물에 대한 형상 최적설계를 수행하였다. 유한요소법 기반 형상 최적설계는 CAD 모델과 해석 모델의 차이로 인해, 설계영역 매개변수화에 어려움이 있다. 등기하 해석법은 CAD 모델과 동일한 NURBS 기저 함수와 조정점을 해석에 이용함으로써 설계의 기하학적 변화를 해석모델에 직접적으로 표현할 수 있는 장점을 가진다. 하중조건이 설계 영역이 변화함에 따라 변하는 최적설계 문제의 경우, 정확한 설계 영역 표현은 법선 벡터, 즉 변화하는 하중의 방향과 곡률과 같은 고차항의 정보를 정확하게 표현할 수 있고, 따라서 목적함수를 최소 또는 최대화시키는 최적의 해로 이끌어 낸다. 유한요소법 또는 밀도법을 이용한 형상 최적설계에서 설계의존형 하중조건을 갖는 구조물의 문제를 푸는 경우, 최적설계가 진행됨에 있어 변화하는 경계의 부정확성 때문에 정확한 설계민감도를 얻기가 어려운 점이 있다. 본 논문에서는, 수치 예제를 통해 등기하 해석 기반의 형상 최적설계 방법론이 설계의존형 하중조건을 갖는 구조물 문제에서 수월성을 가짐을 확인하였다.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.25 no.2
• /
• pp.286-293
• /
• 2021

Smart contract based on the blockchain technology can be applied to the real estate registry including transactions. The Ethereum coin using multi layered protocol is widely accepted as the token for the smart contract. Block chain smart contract using SOLIDITY or PYTHON can mediate transactions auch as sale or lease, creating various scenarios in the property market. Those smart contract can construct the basis for the blockchain real estate registry, which is expected to overcome conventional transaction costs concerning the national law system, the asymmetric information and the currency exchange. The advantages of blockchain technology, namely security, decentralization, global transparency and openness can be applied to the smart contract system on the property registry. Several countries have advanced such blockchain real estate registry project recently, but no actual implementation has been reported for years, owing to institutional and technological impasses.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.24 no.1
• /
• pp.61-67
• /
• 2011

This study is concerned with the shape optimization of structural members frequently found in critical area in a structure system, that is, highly stressed zone. Isogeometry analysis is well known to be the very efficient way to integrate the geometric modeling(CAD) and computational analysis(CAE). This can be accomplished by directly using the geometric modeling by NURBS(Non-Uniform Rational Basis Spline). In this study, an efficient computer code adopting the isogeometry concept has been developed for the structural analysis, in which CAD information can be directly used in the finite element modeling. In order to show the validity of the present code, the present results are compared with those by using the commercial package, that is, MSC/NASTRAN. The present isogeometric analysis procedure has been integrated with the optimization procedure to deal with the optimization problem found in the context of structural mechanics. The present system has been successfully applied to the shape optimization of cantilever structure having bracket. From the present study, it can be seen the validity of the present approach and computer codes developed in this study. This paper ends with some discussions about the practical usefulness of the present approach which is based on isogeometry analysis, and extension of the present study.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.24 no.1
• /
• pp.55-60
• /
• 2011

In the present work, isogeometric analysis in linear elasticity problem is conducted using the basis functions from NURBS. The objectives of isogeometric analysis introduced is to integrate both geometric modeling(CAD) and computational analysis(CAE), and this can be accomplished from direct usage of geometric modeling by NURBS as the computational mesh. The merit of the isogeometry analysis is that NURBS surface are able to represent exact geometry from the control points and knot vectors, and also subsequent refinement is relatively simple relatively. In order to verify the computer codes developed in this study, it has been applied to two structural models of which geometry are simple ; 1) circular cylinder subjected to the constant internal pressure loading, 2) square plate with circular hole at center subjected to uniform tension. The exact solutions of these two models are available. Convergence of the approximate solutions by the present code for the isogeometry analysis are investigated by mesh refinement with inserting knots (h-refinement) and by mesh refinement with order elevation of the basis functions (p-refinement).

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.15 no.4
• /
• pp.191-198
• /
• 2015

The purpose of this study is to develope a current variation control system appropriate to the various LED(Light Emitting Diode) lamps using current control system equipped with microcontroller based voltage regulator of power driving circuit. For this, we will suggest a stable control system of current variation to enable a stable power-supply and current-control, consisting of circuit to minimize the affects on the LED forward voltage using variable resistance and compensating resistance. The method of constant current circuit and energy savings using microcontroller based voltage regulator suggested in this study can be applied to various a big capacity LED lamp to minimize the unnecessay heat generation and to control resistace delicately. Ultimately, we expect the results of this study will upgrade the reliability of LED lamp by supplying the current stably.