• 산업기술연구
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• 제18권
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• pp.241-248
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• 1998

In this study, a modeling method of power-assisted steering systems and driver models for vehicle dynamic analysis using AUTODYN7 is presented. Pressure-flow relations of flow control valve are derived, and the equations of motion of a steering gear are obtained. Combining pressure-flow relations and equations of motion, the steering force can be represented as a function of steering wheel angle or torque. Driver model was modeled based on a PID controller and forward target method. With the steering systems and driver model, various driving tests are conducted using AUTODYN7.

• 산업기술연구
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• 제18권
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• pp.277-287
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• 1998

In this work continuous thermodynamics was adopted for describing the influence of copolymer polydispersity on phase separations in random copolymer solutions. Continuous themodynamic frameworks were formulated using the Flory-Huggin's excess Gibbs free energy model in which the concentration- and temperature-depentent terms of interaction parameter x were modified. Cloud-point curves and coexistence curves of poly(ethylene-vinylactate)/methylacetate solutions and poly(ehtylene-vinylacetate)/ethylacetate solutions were measured, and experimental data were fitted with theoretical relations formulated in this work. Calculated could-point curves were more good ageeable with experimental data than the modified Flory-Huggins's relations. Coexistence curves which were evaluated by using parameters of x estimated from experimental cloud-point curves, were found to coincide with experimental data.

• 산업융합연구
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• 제2권2호
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• pp.127-147
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• 2004

This paper examines the time-series relations among expected return, risk, and book-to-market(B/M) at the portfolio level. The time-series analysis is a natural alternative to cross-sectional regressions. An alternative feature of the time-series regressions is that they focus on changes in expected returns, not on average returns. Using the time-series analysis, we can directly test whether the three-factor model explains time-varying expected returns better than the characteristic-based model. These results should help distinguish between the risk and mispricing stories. We find that B/M is strongly associated with changes in risk, as measured by the Fama and French(1993) three-factor model. After controlling for changes in risk, B/M contains little additional information about expected returns. The evidence suggests that the three-factor model explains time-varying expected returns better than the characteristic-based model.

• Steel and Composite Structures
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• 제26권4호
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• pp.473-484
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• 2018

Free vibration of cross-ply laminated plates using a higher-order shear deformation theory is studied. The arbitrary number of layers is oriented in symmetric and anti-symmetric manners. The plate kinematics are based on higher-order shear deformation theory (HSDT) and the vibrational behaviour of multi-layered plates are analysed under simply supported boundary conditions. The differential equations are obtained in terms of displacement and rotational functions by substituting the stress-strain relations and strain-displacement relations in the governing equations and separable method is adopted for these functions to get a set of ordinary differential equations in term of single variable, which are coupled. These displacement and rotational functions are approximated using cubic and quantic splines which results in to the system of algebraic equations with unknown spline coefficients. Incurring the boundary conditions with the algebraic equations, a generalized eigen value problem is obtained. This eigen value problem is solved numerically to find the eigen frequency parameter and associated eigenvectors which are the spline coefficients.The material properties of Kevlar-49/epoxy, Graphite/Epoxy and E-glass epoxy are used to show the parametric effects of the plates aspect ratio, side-to-thickness ratio, stacking sequence, number of lamina and ply orientations on the frequency parameter of the plate. The current results are verified with those results obtained in the previous work and the new results are presented in tables and graphs.

• 산학경영연구
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• 제9권
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• pp.286-309
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• 1996

• 산학경영연구
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• 제6권
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• pp.255-277
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• 1993

• 대한지리학회지
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• 제48권1호
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• pp.72-86
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• 2013

산업집적은 경제지리학에서 오랫동안 연구되어온 주제 중의 하나이며 지금까지 다양한 방법을 통해 산업집적 현상을 설명하고 이의 영향을 평가해왔다. 하지만 시계열 데이터를 이용해 집적의 추이를 살펴본 연구는 아직 활발히 이루어지지 않고 있다. 본 연구는 지난 29년 간의 데이터를 이용해 사례로 선정된 산업들의 집적 정도를 평가하고 이러한 시계열 패턴과 도로 네트워크의 확장이 어떠한 인과관계를 맺고 있는 지 살펴보고 있다. 집적 정도를 측정한 결과 사례로 선정된 산업의 종사자들은 지리적으로 균등하게 분포되지 않고 있었다. 또한 사례 산업들 간에 공통된 시계열적 변화 특성은 나타나지 않았으나 각 산업의 발전 단계 및 비즈니스 환경 변화가 개별 산업의 집적 정도에 영향을 주고 있는 것으로 보이고 있다. 집적 정도와 도로교통망 사이의 관계를 살펴보기 위해 각 산업 별로 Granger causality test를 실시하였고 도로 교통망이 산업 집적에 영향을 주고 있음을 몇몇 사례를 통해 확인할 수 있었다. 그러나 이와 반대의 경우 혹은 상호 간에 영향을 주는 사례도 나타나 교통망과 산업집적이 보다 복잡한 관계를 맺고 있음을 보여준다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.89-91
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• 2008

This paper deals with the thrust calculations and the measurements of a cylindrical Linear Oscillatory Actuator (LOA) sing Transfer Relations Theorem (TRT), namely, Melcher's methodology. Using transfer relations derived in terms of a magnetic vector potential and a two-dimensional (2-d) cylindrical coordinate system, this paper derives analytical solutions for the magnetic vector potential, magnetic fields due to Permanent Magnets (PMs) and stator winding currents and the thrust. The analytical results are validated by non-linear Finite Element (FE) analyses. In particular, test results such as thrust and back-emf measurements are given to confirm the analysis.

• 대한인간공학회지
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• 제34권5호
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• pp.469-471
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• 2015

Objective: The objective of this paper is to review the interests and limitations of ergonomics regarding intellectual property. Background: There have been less interests in intellectual property among the ergonomics professionals. However, the importance of intellectual property is increasing as competitions in industry are getting fierce. Method: Literatures on the relations of intellectual property with ergonomics were examined, and the international patent classification system was studied. Results: No profound studies were found in the area of the relations of intellectual property with ergonomics. Ergonomics was not considered in patent classification. Conclusion: It is important to induce more interests regarding intellectual property to the community of ergonomics. Further studies are expected on the relations of intellectual property with ergonomics. Application: The results from this paper would be of help to inducing ergonomists to more interests in intellectual property.

• 대한안전경영과학회지
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• 제18권2호
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• pp.119-125
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• 2016

The ratio which we usually use in producing products is nonconforming proportion or percent defective. As our modern society develops, we cannot but meet another proportion in legal, managerial, and medical areas where our human beings might commit various kinds of errors though they do not want them. In this paper we will generally call the ratio 'proportion.' When the size of such proportion as percent defective is observed by persons, it is not true proportion but apparent proportion because it has been observed with human or situational errors. Past studies have not systematically covered the analysis of relations between such proportions and type 1 and 2 error, but this paper analyses and derives such various relations, and it suggests the guideline as sixteen properties for utilization and sensitive analysis of the relations. Current paper's consideration of apparent proportion in addition to true proportion as our familiar concept will open and widen existing academic and application areas where people have mainly built societal, scientific and engineering rules and methods based only on true proportion.