• International conference on construction engineering and project management
• /
• 2015.10a
• /
• pp.618-619
• /
• 2015

The costs due to the maintenance and its method of national road have increased every year, and the maintenance costs have become higher due to the maintenance method without considering the characteristics of each region. This study is a preliminary study regarding the determination of maintenance method according to the characteristics of each region by applying variables (e.g. serviced time, traffic volume, average temperature, maximum temperature, minimum temperature, rainfall, and snowfall) to decide the maintenance and its method through the correlation analysis of road maintenance and repair period for each regional agency using the maintenance history data of national road management agency.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2005.07a
• /
• pp.201-202
• /
• 2005

The electrical characteristics of high-voltage LDMOSFET (Lateral Double-diffused MOSFET) fabricated by a CMOS technology were investigated depending on the process and design parameters. The off-state breakdown voltages of n-channel LDMOSFETs were linearly increased with increasing to the drift region length. For the case of decreasing n-well ion implant doses from $1.0\times10^{13}/cm^2$ to $1.0\times10^{12}/cm^2$, the off-state breakdown voltage was increased approximately two times, however, the on-resistance was also increased about 76%. Moreover, the on- and off-state breakdown voltages were also linearly increased with increasing the channel to n-tub spacing due to the reduction of impact ionization at the drift region.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.30 no.10 s.253
• /
• pp.1202-1208
• /
• 2006

This paper presents an experimental characteristics of electro-hydraulic proportional pressure control valve. In this study, poppet and valve body which are assembled into the proportional solenoid were designed and manufactured. The constant force characteristics of proportional solenoid actuator in the control region should be independent of the plunger position in order to be used to control the valve position in the fluid flow control system. The stroke-force characteristics of the proportional solenoid actuator is determined by the shape (or parameters) of the control cone. In this paper, steady state and transient characteristics of the solenoid actuator for electro-hydraulic proportional valve are analyzed using finite element method and it is confirmed that the proportional solenoid actuator has a constant attraction force in the control region independently on the stroke position. The effects of the parameters such as control cone length, thickness and taper length are also discussed.

• Journal of Welding and Joining
• /
• v.19 no.6
• /
• pp.630-635
• /
• 2001

The characteristics of spatter generation in the short circuit transfer region of $CO_2$ welding was investigated. Spatteriing phenomena could be classified into three types : Type I generated due to the abrupt increase of arc voltage in arcing duration. Type II by the gas ejection from molten metal and Type III generated by the arc instability at the moment of arc re-ignition just after short circuiting. Main observed types were dependent on the chemical composition of welding wires. The case of YCW12 wires was mainly composed of spatters generated by Type l and Type II, while most, spatters in YCW11 wires were generated by Type II and Type III.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.16 no.2
• /
• pp.1-12
• /
• 1991

The purpose of this paper are to find the relations between efficient faces and the regions of weights on the objective functions in Multi-objective Linear Programming. First, we define the region of weights corresponding to an efficient face, and find the changing pattern within the region of weights. Second, we find the eqution of the dimensional relation between the efficient face and the region of weight corrsponding to it.

• Nuclear Engineering and Technology
• /
• v.30 no.2
• /
• pp.164-172
• /
• 1998

This paper presents the detailed modelling of reactor vessel ledge region for the dynamic analysis of the coupled internals and core model. The dynamic responses due to earthquake and pipe break are calculated using the input motions of reactor vessel taken from Ulchin nuclear power plant units 3 and 4. Two different representations for detailed and simplified models of the RV ledge region are made. The dynamic responses of the reactor internals components are compared between them. Response characteristics are reported and simplified model is suggested for earthquake and pipe break analysis for the future design of the reactor internals.

• 한국연소학회:학술대회논문집
• /
• 2006.10a
• /
• pp.73-78
• /
• 2006

The lifted oscillating flame has been studied using experiments of inverse diffusion flames that the air jet injected into a methane background. To find out the characteristics of inverse diffusion flames, fundamentally flame stabilized diagram is investigated with various air and fuel jet velocities. It has five regions - flame extinction, stable attached flame, anchored flame, liftoff flame and blow off region. In inverse diffusion flame, lifted flames were observed near the blow off region. As long as flames lift off, flames oscillate by periods. In this oscillating lifted flame region, the frequency of 1 and under were observed in various air and methane jet velocities. Characteristics of lifted flames are also examined by using the ICCD direct image. And intensity of flame chemiluminescence is very different in rising and falling period from photographs. For the present, it is predicted that the changes of flame structure are related with flame oscillation, but more experiments will be needed to make clear the phenomenon.

• Proceedings of the KOSOMBE Conference
• /
• v.1998 no.11
• /
• pp.62-63
• /
• 1998

In this paper, a new method to find the corpus callosum from sagittal brain MR images is proposed, which uses the statistical characteristics and shape information of corpus callosum. First, we extract regions satisfying the statistical characteristics of the corpus callosum and then find a region matching the shape information. In order to match the shape information, a new directed window region growing algorithm is proposed instead of using conventional contour matching algorithms. Using the proposed algorithm, we adaptively relax the statistical requirement until we find a region matching the shape information. Experiments show very promising results.

• Journal of the Speleological Society of Korea
• /
• no.65
• /
• pp.11-19
• /
• 2004

This study is basic research to present the activation of cave tourism. So first of all for establishing of this study, we examined the distribution characteristics of natural caves and monument caves. The results of this study are as follows; First, monument caves concentrate upon Gangwon-do and Jeju-do. Second, open caves concentrate upon Gangwon-do and Chungcheongbuk-do. Third, typical linkage characteristics of tourism resources surrounding open caves are very high in natural tourism resources. Fourth, It is necessary to develop tourism route though the linkage with other tourism resources. But this study have been partial and fragmentary. In order to increase the number of tourists, we should make them curious about the specific region by presenting the unique characteristics of the region, for example its cultural, social, recreational etc. In other words, in order to attract the tourists open caves should differentiate from other open caves.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.36 no.3
• /
• pp.153-162
• /
• 1987

The purpose of this paper is to analysis and develop theoretically the characteristics of tubular linear induction motor, which is a special industrial motor that generates directly thrust force from electrical power. The Poisson equation about vector potential which is created by the application of Maxwell electromagnetic equation with the speed considered, results in modified Bessel equation by the assumption that is applied to each region of the experimental motor. Vector potential, magnetic flux density, secondary current, and thrust force according to its region respectively were found out by substituting boundary condition for this equation and rearranging. Besides, a attendant materials, that is, thermal characteristic, which is one of the characteristics under the operation of experimental motor each part's magnetic flux distribution characteristics within active zone, the required time for reciprocating motion, and variation of power factor vs. a slip were found.