• Journal of Industrial Technology
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• v.18
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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.

• Journal of Industrial Technology
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• v.18
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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.

• Journal of Industrial Convergence
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• v.2 no.2
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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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• v.26 no.4
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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.

• Korean Business Review
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• v.9
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• pp.286-309
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• 1996

• Korean Business Review
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• v.6
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• pp.255-277
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• 1993

• Journal of the Korean Geographical Society
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• v.48 no.1
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• pp.72-86
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• 2013

Industrial agglomeration is an old theme in economic geography and many studies have been devoted to this topic. But only few have empirically looked at the time trend of industrial agglomeration. This study measured agglomeration of U.S. industries over last 29 years and measurement results indicated that industrial clustering has occurred during the study period in all study industries without a common time trend shared amongst the study industries. The agglomeration levels then were plugged in to investigate causalities, i.e. causal relations, around industrial agglomeration. Three variables were selected to see causal relations with agglomeration levels based on literatures, and our focus was given to the causality between transport network and agglomeration. Causal relation from transport to agglomeration was found in various industries and this supports the argument that the development of transportation influences industrial agglomeration. At the same time inverse and bi-directional causalities were also revealed implying more complex relationship between these two.

• Proceedings of the KIEE Conference
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• 2008.04c
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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.

• Journal of the Ergonomics Society of Korea
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• v.34 no.5
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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.

• Journal of the Korea Safety Management & Science
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• v.18 no.2
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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.