• Mass Spectrometry Letters
• /
• 제4권4호
• /
• pp.87-90
• /
• 2013

Isotope amount ratios of lead in a bronze sample have been successfully determined using multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS). Matrix separation conditions were tested and optimized using ion exchange chromatography with anion-exchange resin, AG1-X8, and sequential elution of the 0.5 M HBr and 7 M $HNO_3$ to separate lead from very high contents of copper and tin in bronze matrix. Mercury was also removed efficiently in the optimized separation condition. The instrumental isotope fractionation of lead in the MC-ICP-MS measurement was corrected by the external standard sample bracketing method using an external standard, NIST SRM 981 lead common isotope ratio standard followed by correction of procedure blank to obtain reliable isotope ratios of lead. The isotope ratios, $^{206}Pb/^{204}Pb$, $^{207}Pb/^{204}Pb$, $^{208}Pb/^{204}Pb$, and $^{208}Pb/^{206}Pb$, of lead were determined as $18.0802{\pm}0.0114$, $15.5799{\pm}0.0099$, $38.0853{\pm}0.0241$, and $2.1065{\pm}0.0004$, respectively, and the determined isotope ratios showed good agreement with the reference values of an international comparison for the same sample within the stated uncertainties

• 대한전자공학회논문지SP
• /
• 제45권4호
• /
• pp.107-114
• /
• 2008

본 논문은 남/여 성별에 기반해 음성을 평상, 기쁨, 슬픔, 화남의 4가지 감성 상태로 분류하는 감성인식 시스템을 구축하였다. 제안된 시스템은 입력 음성으로부터 1차적으로 남/여 성별을 분류하고, 분류된 성별을 기반으로 남/여 각기 최적의 특징벡터 열을 적용하여 감성인식을 수행함으로써 감성인식 성공률을 향상시켰다. 또한 음성인식에서 주로 사용되는 ZCPA(Zero Crossings with Peak Amplitudes)를 감성인식용 특징벡터로 사용하여 성능을 향상시켰으며, 남/여 각각의 특징 벡터 열을 최적화하기 위해 SFS(Sequential Forward Selection) 기법을 사용하였다. 감성 패턴 분류기로는 k-NN과 SVM을 비교하여 실험하였다. 실험결과 제안 시스템은 4가지 감성상태에 대해 약 85.3%의 높은 감성 인식 성공률을 달성할 수 있어 향후 감성을 인식하는 콜센터, 휴머노이드형 로봇이나 유비쿼터스(Ubiquitous) 환경 등 다양한 분야에서 감성인식 정보를 유용하게 사용될 수 있을 것으로 기대된다.

• 한국해양공학회:학술대회논문집
• /
• 한국해양공학회 2003년도 추계학술대회 논문집
• /
• pp.260-265
• /
• 2003

Recently there are operating the Floating Vessel with the positioning control unit in ocean. This technology is not open to industrial society as exclusive one. In order to improve technical competition for its domestic product. It is required to develope the relevant product like above subject. This system consist of DGPS System, Unique Analysis, System Network, and Mooring System and so on. Accordingly Model/Field test were carried out to verify its Function / Performance for application of practical product. In this development, we have prepared the successful result to operate the speedy / accurate / stable unit as shown on this subject 'Development of Positioning Control System for Ship and Offshore using the DGPS'. And also it is expected to install this product for ship and offshore unit.

• 한국기계가공학회지
• /
• 제12권4호
• /
• pp.114-122
• /
• 2013

This study introduces an optimization methodology for the determination of gate location that ensures the melt flow balance within a part cavity of injection mold. A new sequential direct-search scheme based on the recursive reduction of the designer-specified gate design area is developed, and it is integrated with a commercial flow simulation tool for optimization. To quantify the level of melt flow balance, we employ the maximum difference among the fill times for the melt fronts to reach the boundary elements of part cavity as objective function. The proposed methodology is successfully applied in the case study of melt flow balancing in molding of a bar code scanner model. The result shows that the melt flow balance at the optimized gate positions is significantly improved from that for the initial gate position.

• Journal of Mechanical Science and Technology
• /
• 제19권3호
• /
• pp.768-777
• /
• 2005

This paper shows that the performance of a nonlinear fluid engine mount can be improved by an optimal design process. The property of a hydraulic mount with inertia track and decoupler differs according to the disturbance frequency range. Since the excitation amplitude is large at low excitation frequency range and is small at high excitation frequency range, mathematical model of the mount can be divided into two linear models. One is a low frequency model and the other is a high frequency model. The combination of the two models is very useful in the analysis of the mount and is used for the first time in the optimization of an engine mount in this paper. Normally, the design of a fluid mount is based on a trial and error approach in industry because there are many design parameters. In this study, a nonlinear mount was optimized to minimize the transmissibilities of the mount at the notch and the resonance frequencies for low and high-frequency models by a popular optimization technique of sequential quadratic programming (SQP) supported by $MATLAB^{(R)}$subroutine. The results show that the performance of the mount can be greatly improved for the low and high frequencies ranges by the optimization method.

• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 1999년도 추계학술발표대회 논문집
• /
• pp.68-72
• /
• 1999

In an effort to construct a structure under the design principle of minimal use of materials for maximum performances, a discrete gradient structure has been introduced in laminate composite systems. Using a sequential linear programming method, the gradient structure of composites to maximize the buckling load was optimized in terms of fiber volume fraction and thickness of each layer. Theoretical optimization results were then verified with experimental ones. The buckling load of laminate composite showed maximum value with the outmost [$0^{\circ}$] layer concentrated by almost all the fibers when the ratio of length to width(aspect ratio) was less than 1.0. But when the aspect ratio was 2.0, the optimum was determined in a structure where the thickness and fiber volume fraction were well balanced in each layer. From the optimization of gradient structure, the optimal fiber volume fraction and thickness of each layer were proposed. Experimental results agreed well with the theoretical ones. Gradient structures have also shown an advantage in the weight reduction of composites compared with the conventional homogeneous structures.

• Advances in aircraft and spacecraft science
• /
• 제4권4호
• /
• pp.467-486
• /
• 2017

A method for decoupling reliability based design optimization problem into a set of deterministic optimization and performing a reliability analysis is described. The inner reliability analysis and the outer optimization are performed separately in a sequential manner. Since the outer optimizer must perform a large number of iterations to find the optimized shape and size of structure, the computational cost is very high. Therefore, during the course of this research, new multilevel reliability optimization methods are developed that divide the design domain into two sub-spaces to be employed in an iterative procedure: one of the shape design variables, and the other of the size design variables. In each iteration, the probability constraints are converted into equivalent deterministic constraints using reliability analysis and then implemented in the deterministic optimization problem. The framework is first tested on a short column with cross-sectional properties as design variables, the applied loads and the yield stress as random variables. In addition, two cases of curvilinearly stiffened panels subjected to uniform shear and compression in-plane loads, and two cases of curvilinearly stiffened panels subjected to shear and compression loads that vary in linear and quadratic manner are presented.

• 한국자동차공학회논문집
• /
• 제16권3호
• /
• pp.166-171
• /
• 2008

In this paper, the optimization design module for the brake system of a vehicle is developed. As using this module, design variables, that minimize an object function and satisfy nonlinear constraint conditions, can be found easily. Before an optimization is operated, Plackett-Burman design, one of the factorial design methods, is used to choose the design variables which affect a response function significantly. Using the response surface analysis, second order recursive model function, which informs a relation between design variables and response function, is estimated. In order to verify the reliability of the model function, analysis of variances(ANOVA) table is used. The value of design variables which minimize the model function and satisfy the constraint conditions is predicted through Sequential Quadratic-Programming (SQP) method. As applying the above procedure to a real vehicle simulation model and comparing the values of object functions of a current and optimized system, the optimization results are verified.

• 한국항공우주학회지
• /
• 제31권7호
• /
• pp.9-14
• /
• 2003

본 연구에서는 다중블록 격자를 병렬화 하기 위해서 다중블록/다중영역분할 기법을 제안하였다. 이 방법은 각 블록을 사용하고자 하는 프로세서의 개수만큼 나눔으로써 전체 프로세서에 대해서 균일한 로드 밸런싱을 유지할 수 있는 장점이 있다. 영역분할 기법에 따른 병렬화 효율 및 속도 향상률을 비교하기 위해서 다중블록/단일 영역분할 기법과 다중블록/다중 영역분할 기법을 서로 비교 하였으며, 블록간의 격자수가 크게 다른 경우 다중영역 분할 기법이 로드 밸런싱에 있어서 보다 안정적임을 확인 할 수 있었다. 또한 이를 CFDS에 적용함으로써 다중블록 다중영역분할 기법의 효용성을 검증하였다. 3차원 계산의 경우 프로세서 16개를 사용하는 경우 약 12배의 속도 향상률을 보였으며, 다중블록을 병렬화 하는데 있어서 다중블록/다중영역 분할 기법이 효율적인 도구가 될 수 있음을 보였다.

• 한국정보과학회논문지:소프트웨어및응용
• /
• 제36권8호
• /
• pp.623-632
• /
• 2009

본 논문에서는 연속시점에서 촬영한 CT 영상에서 대응되는 폐결절을 추적 관찰하기 위한 폐결절 정합 방법을 제안한다. 제안 방법은 다음과 같은 다섯 단계로 구생된다. 첫째, 분할된 폐를 포함하는 최적경계볼륨의 중심으로 위치 차이를 보정한다. 둘째, 초기 CT 영상과 추적 CT 영상에서 가장 높은 밝기값을 가지고 있는 갈비뼈 구조를 포함하는 관상최대강도투사 영상을 생성한다. 셋째, 두 관상최대강도투사 영상 간의 정규화된 평균 밝기값 차이를 통해 강체 변환을 최적화한다. 넷째, 강체 정합 후에 폐결절 중심 간의 유클라디안 거리 측정을 통해 대응되는 폐결절 대응 후보를 정의한다. 마지막으로, 폐결절을 매칭하기 위하여 초기 CT 영상 내에 폐결절 템플릿과 추적 CT 영상 내에 탐색 볼륨 간의 템플릿 매칭을 수행 한다. 본 제안 방법의 결과를 평가하기 위하여 육안 평가, 정확성 및 수행시간 측정을 수행하였다. 실험결과 관상최대강도투사를 기반으로 하는 강체정합과 지역적 템플릿 매칭을 이용하여 폐결절이 정확하고 빠르게 정합됨을 알 수 있었다.