• IE interfaces
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• v.22 no.4
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• pp.359-367
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• 2009

The vehicle travel time between the demand points in downtown area is greatly influenced by complex road condition and traffic situation that change real time to various external environments. Most of research in the vehicle routing problems compose vehicle routes only considering travel distance and average vehicle speed between the demand points, however did not consider dynamic external environments such as traffic situation by service time zones. A realistic vehicle routing problem which considers traffic situation of smooth, delaying, and stagnating by three service time zones such as going to work, afternoon, and going home was suggested in this study. A mathematical programming model was suggested and it gives an optimal solution when using ILOG CPLEX. A hybrid genetic algorithm was also suggested to chooses a vehicle route considering traffic situation to minimize the total travel time. By comparing the result considering the traffic situation, the suggested algorithm gives better solution than existing algorithms.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.161-162
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• 2018

In this study, it evaluate the impact resistance of UHPC by repeated impact. smooth steel fiber and polyvinyl alcohol fiber were reinforced in UHPC respectively. Overall, the impact resistance of the specimens reinforced with 0.4vol.% PVA fiber was high, and the crater diameter was small in specimens using 13mm fiber. When 19 mm steel fiber is used, the fracture depth is small due to the increase of macro crack resistance compared with other specimens. On the other hand, in the case of the fracture area, it is considered that the use of the fiber of 13 mm causes an increase in the stress dispersion effect to occur small.

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.349-355
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• 2003

Traffic congestion caused by cverpopulation has a major detrimental effect on bringing about social and economic problems ia city area. Therefore Un order to maintain and sustain smooth flow of railway system, we are willing to introduce Light Rail Transit System. Rubber wheel type and guideway far AGT have been concentrated on our study Especially, the prototype of LRT turnout system has been developed. Furthermore, the structural analysis for the guideway system has been completed to secure reliability for the LRT system. In the near future, the tumout system of rubber wheel and guideway shall be applied in Korea. We hope reliability fer the system shall be secured without any major difficulties. As a result, we expect to expedite the localization of rubber wheel type and guideway for AGT.

• Structural Engineering and Mechanics
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• v.14 no.1
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• pp.39-56
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• 2002

In order to trace a target in deep sky, a feed cabin 20 tons in weight used for a large radio telescope is drawn with six cables. To realize a smooth tracing all the time, optimal distribution of the cable tensions is explored. A set of cable-clog systems is utilized to control the wind-induced vibration of the cable-cabin structure. This is an attempt to apply the passive structural control strategy in the area of radio astronomy. Simulations of wind-induced vibration of the structure in both time and frequency domains offer a valuable reference for construction of the next generation large radio telescope.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.320-323
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• 2000

We attempted to fabricate polyurethane derivatives (PU-CN, PU-DCM) LB films by using LB method. Also, we investigated the monolayer behavior at the air-water interface by surface pressure-area ($\pi$-A) isotherms. And, the surface morphologies and the physicochemical properties of LB films were investigated by atomic force microscopy (AFM) and UV-vis spectroscopy, respectively. Also, the electrical properties of polyurethane derivatives LB films were investigated by using the conductivity and the dielectric constant. In the AFM images, we conclude that surface morphology of PU-DCM LB films is smooth and homogeneous and has optimal hydrophobicity and good stability, whereas PU-CN LB films give rougher surfaces with more excess material. In the I-V characteristics, the conductivity is different as to the polyurethane derivatives, it is considered that this phenomena could be described by the difference of lumophore pendant which was adhered at PU main chain.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.6
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• pp.450-453
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• 2020

In this study, ZnO:Ga thin films were fabricated on a glass substrate using various Ar flows by an RF magnetron sputter system at room temperature. The dependencies of Ar flow on different properties were investigated. An appropriate control over the Ar flow led to the formation of a high-quality thin film. The ZnO:Ga films were formed as a hexagonal wurtzite structure with high (002) preferential orientation. The films exhibited a typical columnar microstructure and a smooth top face. The average transmittance was 85~89% within the visible area. By decreasing the Ar flow, the sheet resistance was decreased due to an increase in the grain size and a decrease in the root mean square roughness. The lowest sheet resistance of 86 Ω/□ was obtained at room temperature for the 40 sccm Ar flow.

• Tribology and Lubricants
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• v.25 no.1
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• pp.38-42
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• 2009

Gear is an essential component of an automotive. Crowning is used for tooth modification of a gear. The basic concept of gear tooth crowning is to reduce the stress concentration in edge of contact area and appropriate profile modifications can help gears to resist scoring, pitting, and tooth breakage. In this study, a method to determinate spur gear tooth crowning amount to make smooth surface stress and subsurface stress distribution is proposed. This method is based on the contact analysis.

• Journal of the Korean Mathematical Society
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• v.49 no.4
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• pp.733-743
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• 2012

For the "Hopf bundle" $S^1{\rightarrow}S^{2n,1}{\rightarrow}\mathbb{C}H^n$, horizontal lifts of simple closed curves are studied. Let ${\gamma}$ be a piecewise smooth, simple closed curve on a complete totally geodesic surface $S$ in the base space. Then the holonomy displacement along ${\gamma}$ is given by $$V({\gamma})=e^{{\lambda}A({\gamma})i}$$ where $A({\gamma})$ is the area of the region on the surface $S$ surrounded by ${\gamma}$; ${\lambda}=1/2$ or 0 depending on whether $S$ is a complex submanifold or not. We also carry out a similar investigation for the complex Heisenberg group $\mathbb{R}{\rightarrow}\mathcal{H}^{2n+1}{\rightarrow}\mathbb{C}^n$.

• International Journal of Railway
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• v.2 no.4
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• pp.180-186
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• 2009

High speed railway challenge the design, construction and maintaining of traditional railway, many traditional design concepts have been changed. Transition of railway and bridge has two main problems. one is that different lines have different ability of resisting distortion in area of trial load, which was known that problem of smooth transition of stiffness, the other is that differential settlement between artificial structure and earth structure cause bending of railway. The two problems have effect on train moving. The principle of processing transition of railway and bridge is same in world, but it is difficult to find relationship between design standard of transition, vehicle performance, line standard, design speed and so on form documentation and data reports. Based on mechanics, the paper analyzed dynamic performance of transition of high speed railway, studied various rough elements which is effective to train moving, built mathematical model of interaction of train and transition of high speed railway and developed numerical simulation software. In various different work conditions, we did great quantity of numerical simulation, comprehensive analysis and performance analysis.

• Korea Journal of Hospital Management
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• v.7 no.2
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• pp.52-79
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• 2002

The hospital is characterized by it's remarkable labor industry and human resources input by unit. Recently, the administrative personnel are recognized as an important staff to provide a hospital guidance to consumer and also easiness for consumer's visit to hospital. The purpose of this study is to find the organizational effectiveness of the administrative personnel in hospitals. The survey data involved in the study was derived from 229 personnels working in 3 medium and small sized hospitals and 1 university hospital in Inchon area. The major finding are as follows; 1. The organizational efficiency in accordance with the general characteristics of subjects in order of over 31 years of age, university graduates, long-term tenure and high position is higher, whereas, in as much as wage and well trained personnels in are higher, general hospital's organizational efficiency is higher in comparison with those of university hospital. 2. The organizational efficiency in accordance with satisfaction and the psychological motive contributional factors is higher as much as the high satisfactory level in every hospitals in general. 3. The organizational efficiency in accordance with the factors of job characteristics is higher in as much as difficulty of the jobs is lesser, however there was not statically significance. In as much as job standard level is higher and the more job responsibility the higher organizational efficiency. It was obvious that the higher professional expertise as well as the training and application level are improving the organizational efficiency. 4. The organizational efficiency in accordance with the factors of structural characteristics was higher in as much as the intercommunication was smooth and the structural formalization level are higher, however there was not statically significance between the participation level of decision making and the organizational efficiency. 5. In as much as older age, management of organization and the job level are satisfied, the higher structural formalization level, the smooth intercommunication have affected as major influence factors of organizational efficiency. 6. In the university hospitals is satisfied in the management and job level of hospital organization as there are no difficult jobs while the level of hospital's organizational formality is high and the intercommunication is smooth, which are improving the organizational efficiency. In the general hospitals is also satisfied the management and job level of hospital organization and psychological motive contributional factors is higher, it was apparent that the organizational efficiency is higher in as much as the level of job standardization is high and the intercommunication is smooth. As a result of this study, in order for improving the organizational efficiency of administrative personnel in hospitals, the management and job level as well as personal relation are preferably satisfied, whereas formalization of organization, intercommunication and etc. should be satisfied, and, therefore, it is advisable to buildup discriminated organizational management and environment for different division on the basis above factors. Since this study is carried on four hospitals in Inchon area, there is a certain limit to generalize its result to all domestic hospitals, nevertheless the gallop poll was made by developing the questionnaires with reasonability and reliability. Especially. as the study was carried by analyzing the comparison of influence factors' difference of organizational efficiency in accordance with the divisional characteristics of the university and general hospitals.