• 대한기계학회논문집A
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• 제29권9호
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• pp.1209-1216
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• 2005

Three methods for design sensitivity such as numerical differentiation, analytical method and semi-analytical method have been developed for the last three decades. Although analytical design sensitivity analysis is exact, it is hard to implement for practical design problems. Therefore, numerical method such as finite difference method is widely used to simply obtain the design sensitivity in most cases. The numerical differentiation is sufficiently accurate and reliable for most linear problems. However, it turns out that the numerical differentiation is inefficient and inaccurate because its computational cost depends on the number of design variables and large numerical errors can be included especially in nonlinear design sensitivity analysis. Thus semi-analytical method is more suitable for complicated design problems. Moreover semi-analytical method is easy to be performed in design procedure, which can be coupled with an analysis solver such as commercial finite element package. In this paper, implementation procedure for the semi-analytical design sensitivity analysis outside of the commercial finite element package is studied and computational technique is proposed, which evaluates the pseudo-load for design sensitivity analysis easily by using the design variation of corresponding internal nodal forces. Errors in semi-analytical design sensitivity analysis are examined and numerical examples are illustrated to confirm the reduction of numerical error considerably.

• Steel and Composite Structures
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• 제38권2호
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• pp.223-239
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• 2021

This paper presents the analytical modeling and finite element (FE) analysis, using ABAQUS software, of the new types of steel reinforced lightweight aggregate concrete (SRLAC) columns with cross-shaped (+shaped and X-shaped) steel section, using proposed three analytical and two FE models in total. The stress-strain material models for different components in the columns, including the confined zones of the lightweight aggregate concrete (LWAC) using three and four concrete zones divisions approaches and with and without taking into account the stirrups reaction effect, are established first. The analytical models for determining the axial load-deformation behavior of the SRLAC columns are drawn based on the materials models. The analytical and FE models' results are compared with previously reported test results of the axially loaded SRLAC columns. The proposed analytical and FE models accurately predict the axial behavior and capacities of the new types of SRLAC columns with acceptable agreements for the load-displacement curves. The LWAC strength, steel section ratio, and steel section configuration affect the contact stress between the concrete and steel sections. The average ratios of the ultimate test load to the three analytical models and FEA model loads, Put /Pa1, Put /Pa2, Put /Pa3, and Put /PFE1, for the tested specimens are 0.96, 1.004, 1.016, and 1.019, respectively. Finally, the analytical parametric studies are also studied, in terms of the effects of confinement, LWAC strength, steel section ratio, and the reinforcement ratio on the axial capacity of the SRLAC column. When concrete strength, confinements, area of steel sections, or reinforcement bars ratio increased, the axial capacities increased.

• 분석과학
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• 제21권5호
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• pp.345-363
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• 2008

이미 석유화학산업 등 대규모 산업공정에서 널리 활용되고 있는 공정분석화학 및 공정분석기술의 역사는 오래되었지만, 최근 "공정분석기술(Process Analytical Technology: PAT)"의 새로운 개념이 매우 빠르게 일부 산업분야의 생산공정에 보급되고 있다. 본 총설에서는 이미 오래 전부터 대규모 연속식 생산라인에서 널리 활용되어 왔던 공정분석화학 및 공정분석기술의 신개념 첨단 분석기술로서의 태동 배경과 용어 정의 등을 명확히 하였다. 또한, 공정최적화를 위한 공정분석화학 혹은 공정분석기술의 기본개념, 계량화학 등의 공정분석화학 핵심요소, 국내외 산/학/연의 기술 및 활동 현황 등에 관하여 다루었고, PAT에서 주로 활용되고 있는 공정분석기기의 종류와 현황, 그리고 미래 유망기술 및 활용분야에 대해서도 소개하였다.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.769-777
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• 2017

The research of air gap flux density has a significant effect on predicting and optimizing the structure parameters of electrical machines. In the paper, the air gap coefficient, leakage flux factor and saturation coefficient are first analytically expressed in terms of motor properties and structure parameters. Subsequently, the analytical model of average air gap flux density for surface-mounted permanent magnet synchronous machines is proposed with considering slotting effect and saturation. In order to verify the accuracy of the proposed analytical model, the experiment and finite element analysis (FEA) are used. It shows that the analytical results keep consistency well with the experimental result and FEA results, and the errors between FEA results and analytical results are less than 5% for SPM with high power. Finally, the analytical model is applied to optimizing the motor structure parameters. The optimal results indicate that the analytical calculation model provides a great potential to the machine design and optimization.

• Journal of Welding and Joining
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• 제13권2호
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• pp.68-81
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• 1995

This paper presents an analytical solution to predict the transient temperature distribution in fillet arc welding. The analytical solution is obtained by solving a transient three -dimensional heat conduction equation with convection boundary conditions on the surfaces of an infinite plate with finite thicknesses, and mapping an infinite plate onto the fillet weld geometry with energy equation. The electric arc heat input on fillet weld and on infinite plate is assumed to have a traveling bivariate Gaussian distribution. To check the validity of the solution, GTA and FCA welding experiments were performed under various welding conditions. The actual isotherms of the weldment cross - sections at various distances from the arc start point are compared with those of simulation result. As the result shows a satisfactory accuracy, this analytical solution can be used to predict the transient temperature distribution in the fiIIet weld of finite thickness under a moving bivariate Gaussian distributed heat source. The simplicity and short calculation time of the analytical solution provides rationales to use the analytical solution for modeling the welding control systems or for an optimization tool of welding process parameters.

• 한국수학사학회지
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• 제20권1호
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• pp.17-32
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• 2007

이 논문에서는 19세기 초에 영국 케임브리지 대학에서 나타났던 '해석학회'를 중심으로 18세기 후반에서 19세기 전반까지의 영국 수학계의 상황을 살펴볼 것이다. 이를 통해 흔히 매우 새롭고 혁신적인 사건으로 언급되는 해석학회의 등장이 19세기 이전 영국 수학계의 꾸준한 개혁 노력들이 축적된 결과 나타날 수 있었음을 보일 것이다. 그 결과 해석학회의 역할과 의의에 대해 새롭게 이해할 수 있게 될 것이다. 또한 이후 영국에서 해석적 방식이 받아들여졌던 과정과 그 경로를 통해 새로운 해석적 방식이 당시 영국의 독특한 지적, 사회적 상황 속에서 대륙과는 다른 방식으로 발전했던 과정을 이해할 수 있을 것이다.

• 전기학회논문지
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• 제65권10호
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• pp.1639-1647
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• 2016

This paper deals with eddy current loss analysis of Slotless Double sided Cored type permanent magnet linear generator by using analytical method, space harmonic method. In order to calculate eddy current, this paper derives analytical solution by the Maxwell equation, magnetic vector potential, Faraday's law and a two-dimensional(2-D) cartesian coordinate system. First, we derived the armature reaction field distribution produced by armature wingding current. Second, by using derived armature reaction field solution, the analytical solution for eddy current density distribution are also obtained. Finally, the analytical solution for eddy current loss induced in permanent magnets(PMs) are derived by using equivalent, electrical resistance calculated from PMs volume and eddy current density distribution solution. The analytical result from space harmonic method are validated extensively by comparing with finite element method(FEM).

• Steel and Composite Structures
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• 제22권3호
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• pp.627-645
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• 2016

When an eccentrically braced frame (EBF) is subjected to severe earthquakes, the links experience inelastic deformations while beams outside of the link, braces and columns are designed to remain elastic. To perform reliable inelastic analyses of EBFs sufficient analytical model which can accurately predict the inelastic performance of the links is needed. It is said in the literature that available analytical models for shear links generally predict very well the maximum shear forces and deformations from experiments on shear links, but may underestimate the intermediary values. In this study it is shown that available analytical models do not predict very well the maximum shear forces and deformations too. In this study an analytical model which can accurately predict both maximum and intermediary values of shear force and deformation is proposed. The model parameters are established based on test results from several experiments on shear links. Comparison of available test results with the hysteresis curves obtained using the proposed analytical model established the accuracy of the model. The proposed model is recommended to be used to perform inelastic analyses of EBFs.

• Mass Spectrometry Letters
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• 제9권4호
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• pp.105-109
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• 2018

A certified reference material (CRM) for the analysis of inorganic nutrients in nutritional supplements has been developed. Accurate mass fractions of chromium (Cr), iron (Fe), copper (Cu), and zinc (Zn) were determined by isotope dilution inductively coupled plasma mass spectrometry (ID ICP/MS). The measurement results were used to assign certified values for the CRM, which were metrologically traceable to the definitions of the measurement units in the International System of Units (SI). Production of a candidate reference material (RM) and the certification processes are summarized. Each nutrient in the CRM showed good homogeneity, which was estimated using relative standard deviations of the measurement results of twelve bottles in a batch. This CRM is expected to be an important reference to improve reliability and comparability of nutrient analyses in nutritional supplements and related samples in analytical laboratories.

• Asia Marketing Journal
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• 제22권2호
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• pp.59-85
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• 2020

Combining prior theories on innovation newness with information processing style (imagery vs. analytical), this study presents a theoretical framework; develops hypotheses; and makes predictions on how analytical versus imagery ads influence consumers differently depending on the newness level of products. The study shows that consumers are more likely to evaluate RNPs (radically-innovative new products) positively when they are advertised with imagery cues. Compared with analytical advertisements, imagery advertisements increased advertising effectiveness, product evaluation, and purchase intention of RNPs. These effects were demonstrated by using stimuli from two product categories consisting of washing machines and cars. In particular, in advertisement for RNPs, verbal description that induced imagery processing, such as "picture yourself using this product," was more effective in generating favorable responses, compared to verbal description that induced analytical processing, such as explanation of product attributes. This difference was present for RNPs, but not for INPs (incrementally-innovative new products). INPs are continuous innovations that are easier to understand, thus imagery ads do not provide additional advantage for consumers in understanding the innovation, compared to analytical ads. In RNPs, imagery ads can highlight new benefits that may have been neglected or undervalued by consumers, leading to greater message persuasiveness. Implications for marketing of RNPs are discussed.