• 한국항해학회지
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• 제25권1호
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• pp.45-52
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• 2001

본 논문은 선체구조에 많이 이용되고 있는 보강판 구조물의 동적 특성을 최적 변경하는데 그 목적이 있다. 유한요소법(FEM), 동적 감도해석법, 최적구조 변경법을 이용하여 보강판의 동적 특성을 최적화한다. 먼저, FEM을 이용하여 보강판 구조물의 동적 특성을 해석한다. 다음으로 설계변수의 변화에 따른 동적 특성의 변화율을 동적 감도해석법으로 해석한다. 감도해석법으로 구한 감도값과 최적구조 변경법을 이용하여 설계변수들의 변경 량을 계산한다. 보강판 구조물의 고유진동수의 변경을 목적함수로 하고, 보강판의 두께와 보강재의 단면2차 모우멘트를 설계 변수로 한다. 본 논문에서 이용한 최적구조 변경법이 보강판 구조물의 동특성을 최적화하는데 유용함을 보여준다.

• 전산구조공학
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• 제10권4호
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• pp.177-184
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• 1997

이 논문은 한개의 집중하중을 받는 단순지지 변화곡선길이 보에 관한 연구이다. Bernoulli-Euler 보 이론에 의하여 정확탄성곡선을 지배하는 미분방정식을 유도하고 이를 수치해석하여 정확탄성곡선의 거동값들을 예측하였다. 미분방정식을 적분하기 위하여 Runge-Kutta method를 이용하고, 단부의 회전각을 산출하기 위하여 Regula-Falsi method를 이용하였다. 본 연구에서의 수치해석 결과들은 문헌값들과 매우 잘 일치하여 본 연구방법의 타당성을 입증하였다. 수치해석의 결과로 정확탄성곡선의 거동값과 하중사이의 관계 및 한계거동값과 하중위치변수 사이의 관계를 각각 그림에 나타내었다. 수치해석의 결과를 분석하여 변화곡선길이 보에서 발생가능한 최대 단부회전각, 최대 처짐 및 최대 휨모멘트를 산정하였다.

• Journal of the Korean Data and Information Science Society
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• 제25권6호
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• pp.1301-1313
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• 2014

대학에서는 다양한 분야의 지식과 정보가 창출되고 공유되는데 이러한 대학이 제공하는 교육서비스의 주된 장소가 도서관이다. 이 연구에서는 K대학생들을 대상으로 조사하여 제공자료 만족도, 환경 및 시설 만족도, 서비스 만족도가 이용자 만족도의 매개에 의해서뿐만 아니라 직접적으로도 이용자 충성도에 영향을 미칠 것이라는 가설을 구조방정식모형을 통해 분석하였다. 분석결과 제공자료 만족도, 환경 및 시설 만족도, 서비스 만족도는 이용자 만족도의 매개에 의해서뿐만 아니라 직접적으로도 이용자 충성도에 영향을 미치는 것으로 나타났다.

• Smart Structures and Systems
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• 제13권2호
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• pp.319-341
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• 2014

A family of smart tuned mass dampers (STMDs) with variable frequency and damping properties is analyzed under harmonic excitations and ground motions. Two types of STMDs are studied: one is realized by a semi-active independently variable stiffness (SAIVS) device and the other is realized by a pendulum with an adjustable length. Based on the feedback signal, the angle of the SAIVS device or the length of the pendulum is adjusted by using a servomotor such that the frequency of the STMD matches the dominant excitation frequency in real-time. Closed-form solutions are derived for the two types of STMDs under harmonic excitations and ground motions. Results indicate that a small damping ratio (zero damping is the best theoretically) and an appropriate mass ratio can produce significant reduction when compared to the case with no tuned mass damper. Experiments are conducted to verify the theoretical result of the smart pendulum TMD (SPTMD). Frequency tuning of the SPTMD is implemented through tracking and analyzing the signal of the excitation using a short time Fourier transformation (STFT) based control algorithm. It is found that the theoretical model can predict the structural responses well. Both the SAIVS STMD and the SPTMD can significantly attenuate the structural responses and outperform the conventional passive TMDs.

• 아태비즈니스연구
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• 제14권4호
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• pp.1-21
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• 2023

Purpose - The study investigates the role of authenticity of B2B salespersons has on their consultative selling competence. The study also examines the mediating effect of customer orientation between the authenticity of B2B salespersons and their consultative selling competence, as well as the moderating role of trust in the buyer-seller exchange. Design/methodology/approach - This research utilized a covariance-based structural equation model technique. The study assessed the research model's moderation effects through a stepwise approach, which allowed for an examination of the moderating effect of trust in the buyer-seller relationship. Findings - As a result of structural equation analysis, this study found that the authenticity of B2B salespersons influences their consultative selling competence by mediating their customer orientation significantly. In addition, trust in the buyer-seller exchange plays a significant role as a moderating variable between customer orientation and competitive selling competence, but it is not significant as a moderating variable between the authenticity and customer orientation of B2B salespersons. Research implications or Originality - This research proposed the role of authenticity of the B2B salesperson as a key factor in the trust-based relationship and a key variable of consultative selling competence. The study has taken the research on the authenticity of the B2B salesperson one step further from the study of authenticity of the brand and the company's leadership.

• Structural Engineering and Mechanics
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• 제52권1호
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• pp.19-33
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• 2014

Structural robustness refers to the ability of a structure to avoid disproportionate consequences to the original cause. Currently attentions focus on the concepts of structural robustness, and discussions on methods of robustness based structural design are rare. Firstly, taking basis in robust $H_{\infty}$ control theory, structural robustness is assessed by $H_{\infty}$ norm of the system transfer function. Then using the SIMP material model, robustness based design of grid structures is formulated as a continuum topology optimization problem, where the relative density of each element and structural robustness are considered as the design variable and the optimization objective respectively. Generalized elitist genetic algorithm is used to solve the optimization problem. As examples, robustness configurations of plane stress model and the rectangular hyperbolic shell model were obtained by robustness based structural design. Finally, two models of single-layer grid structures were designed by conventional and robustness based method respectively. Different interference scenarios were simulated by static and impact experiments, and robustness of the models were analyzed and compared. The results show that the $H_{\infty}$ structural robustness index can indicate whether the structural response is proportional to the original cause. Robustness based structural design improves structural robustness effectively, and it can provide a conceptual design in the initial stage of structural design.

• 대한조선학회논문집
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• 제54권4호
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• pp.312-320
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• 2017

This paper deals with the development of structural test facility for the strength assessment of marine leisure boat built from carbon fiber reinforced plastics (CFRP) materials. The structural test facility consists of test jig, load application and control system, and data acquisition system. Test jig, and load application and control system are designed to accommodate various size and short span to depth ratios of single skin, top-hat stiffened and sandwich constructions in plated structural format such as square and rectangular shapes. A lateral pressure load, typical and important applied load condition to the plates of the hull structure for marine leisure boat, is simulated by employing a number of hydraulic cylinders operated automatically and manually. To examine and operate the structural test facility, five carbon/epoxy based FRP square plates having the test section area of $1m^2$, which are part of CFRP marine leisure boat hull, are prepared and they are subjected to monotonically increasing lateral pressure loads. In the test preparation, considering the symmetry of the plates geometry, various strain gauges and linear variable displacement transformer are used in conjunction with data acquisition system utilizing LabVIEW. From the test observation, the responses of the CFRP hull structure of marine leisure boat are understood by obtaining load to deflection and strain to load curves.

• Journal of Power Electronics
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• 제12권1호
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• pp.67-74
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• 2012

According to electrical output up rating of a permanent magnet motor and request to operate for a large variable speed range, resonance between structural natural vibration and electromagnetic force inside the motor can take place and make noise. This paper describes the mechanism of a resonance between them and noise lowering procedure by frequency shift when they are applied to the reluctance torque largely employed new motor named Permanent magnet Reluctance Motor (PRM).

• Communications for Statistical Applications and Methods
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• 제18권4호
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• pp.495-505
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• 2011

본 연구에서는 표본의 일부를 단계적으로 증가시켜 가며 반복적으로 추정된 장기모수의 시간경로를 파악하는 방식으로 변수들 간 장기균형관계의 안정성에 대해 통계적으로 검정해 보았다. 안정성 귀무가설이 기각되는 구간에는 더미변수를 사용해 전체 연구기간에 걸쳐 안정성을 회복시키고 타당한 공적분관계를 도출해 보았으며, 오차수정항에 대한 분석결과는 더미변수가 공적분관계의 구조변화를 반영하는 것으로 나타났다.

• 한국전기전자재료학회논문지
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• 제26권4호
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• pp.321-324
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• 2013

In this study, The RF magnetron sputter and evaporator was on glass substrates 30 mm ${\times}$ 30 mm OMO multilayer thin film structure is applied to the low-e. Structural and optical properties, a thin film was produced, the variable was placed into a variable deposition time of the oxide layer. According to the XRD measurement results there is no peak that satisfies the Bragg's law ($2dsin{\theta}=n{\lambda}$) which confirmed that it is an amorphous structure. RMS value of the results of the AFM measurement, has a roughness of less than 2 nm. transmittance measurements results, visible light region an average 80%, IR region 40% showed.