• Proceedings of the KSR Conference
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• 2002.05a
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• pp.250-255
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• 2002

The transition between bridge and earthwork often causes the problems of maintenance. The damages of the track on the transition area influence running safety of train and serviceability, increase the maintenance cost. Therefore it is very important to evaluate the dynamic responses of transition and take a efficient measure. In order to evaluate the dynamic behavior of track, the field estimations are performed at the transition area of a conventional line between bridge and earthwork. And the track system on the transition area numerically analyzed to evaluate the dynamic behavior of damaged track with void sleeper. The measured values and Analysis results such as wheel contact force, rail stress, displacement acceleration and track irregularity in the transition area show the dynamic forces are severe. So it is recommended that the transition area should be improved the rigidity by reinforcing the rail.

• Proceedings of the KSR Conference
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• 2001.05a
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• pp.281-288
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• 2001

In order to evaluate the effect of impact load at support stiffness transition area, the field estimations are performed at the transition zone between earthwork and bridge on test operation of KTX. Due to differential settlement caused by the variations of track support stiffness, large impact forces are investigated. However, the measured values such as wheel load, rail stress, displacement and acceleration in the transition area shows that the stiffness changes in the transition area are not abrupt, and the stiffness in the infra track structure varies continuously. In this experimental study, the parameters influencing safety of transition area are not governed by partial or local stiffness because cumulative passing loads are not sufficient on test operation of KTX.

• International Journal of Highway Engineering
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• v.10 no.3
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• pp.97-107
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• 2008

I study for design criteria and research about Interchange diverging area of express highway and freeway, the most recent, at interchange diversion of express highway and freeway, design criteria and researches are focus on safety guarantee a point of view movement dynamics of vehicle and road geometric as to transition section, deceleration section, curve radius, nose section, outflow angle etc, that is, design criteria and research of Interchange diverging area have not consider a point of view movement dynamics of vehicle and road geometric and driver, so that I will be focus characteristic of runing speed on trasion curve. and I will consider vehicle running speed characteristics and study problem of Interchange diverging area design criteria. For this study, First, analysis meaning about theory of now design criteria, Second, look at vehicle running speed and traffic accident characteristics of Interchange diverging area, Third, propose new deceleration transition curve design method get along vehicle running speed characteristics of Interchange diverging area. new deceleration transition curve design method put out new outcoums, that is, I definite cause to safety new deceleration transition curve design method better than pressently, used design criteria of Interchange diverging area, especially, deceleration transition curve design criteria produced good result in the running speed 50km/h, 40km/h, that is inertia better than inertia of present used design criteria. and deceleration transition curve is extended better than present transition curve criteria, so that new deceleration transition curve design method safety is good better than the past method safety.

• Polymer(Korea)
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• v.26 no.5
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• pp.653-660
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• 2002

The volume phase transition of poly(N-isopropylacrylamide) (PNIPAAm) and poly (N-isopropylacrylamide-co-sodium methacrylate) (P (NIPAAm-co-SMA)) hydrogels crosslinked with poly (ethylene glycol) diacrylate (PEGDA) was investigated in consideration of water content and surface area. The volume phase transition temperature of hydrogel was not affected by the concentration of crosslinking agent, which increased over 40$\^{C}$ by incorporating a small amount of SMA. Higher volume phase transition temperature was obtained when PEGAD was used as a crosslinking agent, suggesting that the chain length of crosslinking agent had a significant effect on the volume phase transition temperature. The surface area of PNIPAAm and P (NIPAAm-co-SMA) gels fell off around the volume phase transition temperature, resulting from the fact that the size of pores reduced remarkably in the course of the volume phase transition. Hence, the surface area and the pore size were considered to be important factors indicating the volume phase transition.

• Journal of Korean Society of Transportation
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• v.31 no.4
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• pp.58-66
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• 2013

Due to the characteristics of urban freeways such as heavy traffic and high speed, work zone on urban freeways causes the increase of not only the likelihood of crash occurrence but also traffic congestion caused by lane drop, lane change, acceleration/deceleration, and etc. This paper aims to determine the proper length of transition area that satisfies two criteria, mobility and safety, to make the operation of work zone more efficient. For the analysis, three different scenarios were developed by the number of lanes and the proper length of transition area were determined by changing the length from 100m to 500m in 100m increments. The results showed that the proper length of transition area for 3- and 4-lane freeways is 300m, whereas the proper length of 2-lane freeways is 200m. The results indicated that the different length of transition area based on the number of lanes is more desirable and efficient.

• Journal of Energy Engineering
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• v.21 no.4
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• pp.362-372
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• 2012

The steam generator tubes of nuclear power plants are pressure boundaries, and if tubes are leaked, the coolant with the radioactive materials was flowed out from the primary system to the secondary system and polluted the plant and the air. Recently most crack defects of tubes are stress corrosion cracks and these defects are located in expansion transition area, sludge pile-up region, and U-bend area. The most effective one of crack initiation factors in expansion transition area and U-bend area is the residual stress. According to the experiences of Korea standard nuclear plants(Optimized Power Reactor-1000), they had the stress corrosion cracks at the tube expansion transition area in early operating stage and especially lots of circumferential cracks were occurred. Therefore in this study, the distributions and conditions of residual stresses by tube expansion methods were compared and the dominant reason of a specific direction was examined.

• Journal of Korean Academy of Nursing Administration
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• v.4 no.1
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• pp.129-150
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• 1998

The purpose of this study was to exame the effect of the planned indoctrination program on the role transition of new graduate nurses in one educational hospital located in Seoul. The planned in doctrination program was a 1-month program and consisted of 3 days induction and 22 days orientation- socialization. The simulated control group pretest-posttest research was designed for this study. One hundred and twenty subjects were selected from the new graduate nurses who were employed by the Seoul National Univerty Hospital. Sixty of them were assigned to the pretest, and the rest to the posttest. To collect the data on role transition, the researcher developed the instrument, measuring 3 differert areas : inducction, orientation, and socialization. The reliability of the instrument were induction area's Chronbach ${\alpha}$ .8291, orientation area's Chronbach ${\alpha}$ .9809, and soialization area's Chronbach ${\alpha}$ .8524. The data were collected from Aprial to October 1995 at three different times: (1) immediately before indoctrination program began, (2) immediately after the program ended, and (3) 2 months after the program ended. In addition to the self-report of the subjects, their superiors filled out the same instrument on role transition to compare the scores between the subjects and their superiors at 2 months after the program. T-test was utilized to test differences between the means of pre- and post-tests. The result of this study are as follows : 1. There was a significant difference in the mean scores between before and immediately after the indoctrination program (t=-12.65, P=.000). There were significant differences in all 3 areas of role transition. 2. There was a significant difference in the mean scores between immediately after and 2 months after the program (t=-2.91, P=.004), Among 3 areas of role transition, however, only in the orientation area was there significant difference (t=-3.26, P=.001). 3. There was no significant difference in total mean scores between subjects' self-report and their superiors' report 2 months after the program ended (t =.97, p= .335). Among 3 different areas, however, there was a significant difference in the induction area (t=2.41, P=.018). 4. There was significant difference in mean scores between the group Of 3-year diploma and 4-year bachelor's degree only at pretest (t=-2.56, P= .013), but not at two posttests (t=-1.08, P=.250: t=-.34, P=.733). In conclusion, the planned indoctrination program for new graduate nurses was proved to be effective on the role transition in the study. But the result in the study showed that the indoctrination program had not equal effect On 3 different areas of role transition. There were significant differences in the scores between after and 2 months after the program only in the orientation area. These suggest that indoctrination program should be developed more focusing on induction and socialization areas to help new graduate nurses have a high morale and enthusiasm for the organization. Also contineous program to facilitate induction and socialization might be necessary for them to have a successful role transition.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.351-357
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• 2007

The transition zone between railway embankment and structures, or different track types is known to be an area in which problems often arise and where extra care needs to be taken with maintenance. Differences in track stiffness have dynamic effects and these increase the force in the track and the extent of deformation. In this study, the criteria for the change ratio of track stiffness along transition area, and proper transition length are presented through train/track interaction analyses. Those are derived on the basis of permissible limitations of train and track performances such as rail stress, uplift force of fastener, reduction of dynamic wheel force, and acceleration of car body. A feasible method of evaluation of track stiffness which is necessary when a designer reviews whether the criteria are satisfied or not is also presented.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.334-342
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• 2005

A numerical analysis is performed using two dimensional axisymmetric RANS (Reynolds Averaged Navier-Stokes) equations system on the transition sequence of the Integrated Rocket Ramjet and the unsteady reacting flow-field in a ramjet combustor during unstable combustion. The mode transition of an axisymmetric ramjet is numerically simulated starting from the initial condition of the boost end phase of the entire ramjet. The unsteady reacting flow-field within combustor is computed for varying injection area. In calculation results of the transition, the terminal normal shock is occurred at the downstream of diffuser throat section and no notable combustor pressure oscillation is observed after certain time of the inlet port cover open. For the case of a small injection area at the same equivalence ratio, periodic pressure oscillation in the combustor leads to the terminal shock expulsion from the inlet and hence the buzz instability occurred.

• Journal of Digital Convergence
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• v.9 no.6
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• pp.153-163
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• 2011

This study analyzes the military and political factors that influenced the Participatory Government's resolution in Wartime Operational Control (OPCON) Transition. The research on key factors in OPCON transition firstly implemented literature research and then increased feasibility through additional use of AHP. The analysis results showed that there was a negative effect for Korean Peninsular Defense in the 'ROK-US Alliance Asymmetry' area, a positive effect to increase ROK-led Capability of Theater Operation in the 'ROK and U.S. Alliance Interdependence' area and a positive effect for Invocation of ROK Self-Defense Power in the 'Interests of Participatory Government's Liberal Regime' area respectively. After applying AHP, "ROK exercise of Self-defense" in the 'Interests of Participatory Government's Liberal Regime' area received the highest assessment, while the "Increasement of North Korea's Threat" in the 'ROK-US Alliance Asymmetry' area received the lowest assessment. This study is meaningful in that it analyzed the key military and political factors in the Participatory Government's resolution of Wartime OPCON Transition using AHP.