• Journal of Industrial Technology
• /
• v.17
• /
• pp.277-289
• /
• 1997

The numerical model for prediction of longshore current with set-up/down effect on a plane beach is developed using the longshore component of the depth-integrated momentum balance equation. To predict the longshore current, the wave height model should first be formulated because the longshore current depends on the wave height directly. Two wave model, regular wave model and random wave model, are developed based on the energy flux balance equation. Also, the numerical model estimating the set-up inside the shoreline is developed using both the on-offshore momentum equation and the moving boundary technique. The numerical models are verified by the analytical solution, and compared with laboratory data. It is found from the comparison that developed models may be predicted accurately the longshore current with set-up/down effect on a plane beach.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.22 no.3
• /
• pp.408-415
• /
• 1998

This study presents experimental results on the shut-down and start-up characteristics of a residential split-system air-conditioner with capillary tube, using R410A as a R22 alternative refrigerant. During shut-down, the transient characteristics are evaluated by measuring the high side and low side pressures and temperatures of the system. The dynamic behavior of the system after start-up is also investigated at the high temperature cooling test condition. All experiments are performed in psychrometric calorimeter. The cooling capacity, power consumption, dehumidification capacity and cycle characteristics after start-up are analyzed.

• Journal of the Korean Chemical Society
• /
• v.36 no.2
• /
• pp.169-173
• /
• 1992

The surface geometry of o-diiodobenzene (ODIB) adsorbed on silver colloid surfaces has been studied. This molecule is standing up on 1 day old colloid surfaces, while it is lying down or standing up on 1 month old colloid surfaces. The surface geometry of ODIB is affected by the atomic scale surface roughness of colloid used. The SERS intensity of ODIB for lying down geometry is much more strong than that for standing up. This may be mainly due to that the distance from surface to the center of the molecule in lying down geometry is shorter than that in standing up.

• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.69.6-69
• /
• 2001

The SSPA makes the power level of EIRP up to 16W, and compensates for temperature to the SSPA´s maximum stability. The up and the down converters are dually conversed like as individual synthesizers for selecting of independent transmit-receive transponder. The function of the up-converter is to convert the 70MHz IF signal modulated in the indoor unit modem into a 14.0 ∼ 14.5 GHz Ku-band up-link signal to be sent to the antenna. The down-converter converts the 12.25 ∼ 12.75 GHz Ku-band down-link signal or a trouble malfunction of SSPA may be a fatal factor to operation of the whole satellite communication network. Therefore, this study developed the remote monitoring and control program to monitor the SSPA´s status before the problem occurs for stable operation of the system. This software ...

• Proceedings of the KSR Conference
• /
• 2003.05a
• /
• pp.251-256
• /
• 2003

This study focuses on the development of the conceptual criteria which could be applied to the speed-up strategy of urban rail operation. Down town segment or not, and peak hour or not are the criteria. The author suggests that in the case of down town segment and peak hour urban rail should take the all-stop pattern, if down town segment and off peak hour, then skip-stop pattern, if not-down town segment and peak hour, the A, B skip-stop, and if not-down town segment and off peak hour, the A, B, C skip-stop. If side lines, three rail, or 2 double lines, then express train operation is recommended in the peak hour. Then this study recommends speed-up strategies of each 8 urban lines.

• ETRI Journal
• /
• v.27 no.5
• /
• pp.569-578
• /
• 2005

The purpose of this paper is to describe the implementation of monolithically matching circuits, interface circuits, and RF core circuits to the same substrate. We designed and fabricated on-chip 1 to 6 GHz up-conversion and 1 to 8 GHz down-conversion mixers using a 0.8 mm SiGe hetero-junction bipolar transistor (HBT) process technology. To fabricate a SiGe HBT, we used a reduced pressure chemical vapor deposition (RPCVD) system to grow a base epitaxial layer, and we adopted local oxidation of silicon (LOCOS) isolation to separate the device terminals. An up-conversion mixer was implemented on-chip using an intermediate frequency (IF) matching circuit, local oscillator (LO)/radio frequency (RF) wideband matching circuits, LO/IF input balun circuits, and an RF output balun circuit. The measured results of the fabricated up-conversion mixer show a positive power conversion gain from 1 to 6 GHz and a bandwidth of about 4.5 GHz. Also, the down-conversion mixer was implemented on-chip using LO/RF wideband matching circuits, LO/RF input balun circuits, and an IF output balun circuit. The measured results of the fabricated down-conversion mixer show a positive power conversion gain from 1 to 8 GHz and a bandwidth of about 4.5 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.12 no.6
• /
• pp.994-1001
• /
• 2001

In this paper, we propose the Improved SIR-based Power Control method in mobile communication system. Generally speaking, SIR-based design considering both channel noise and multiuser interference is accurate indication of signal quality and provides good performance. However, one serious problem associated with SIR-based Power Control is the potential of Positive Feedback which can endanger the stability of the system. Therefore from SIR definition, we decrease the signal\`s Interference we will got a improved SIR and have a stable power control Also in mobile using window register which has Up-Maintain-Down power control step size instead of Up-Down, we got a better performance. This paper assesses the performance of Improved SIR based Power Control using PIC and window register. The proposed Improved SIR based Power Control is presented and compared with existing SIR based Power Control and Strength-and-SIR based Power Control.

• Journal of Korean Society of Steel Construction
• /
• v.13 no.4
• /
• pp.433-441
• /
• 2001

Thus study presents the basic concepts of 3 span continuous preflex composite beam of bridges by re-up down of supports and analysis relationship of between variables and stress of critical section. Also, it shows the pre-compression effects of re-up down of supports method by presenting the difference of between old section and new section got from new method. This study's new method makes more economic sections to be possible and when the sections designed with the existing method are used in the new method. efficient stress state is accomplished.

• Journal of the Korean Society for Precision Engineering
• /
• v.18 no.7
• /
• pp.143-148
• /
• 2001

In this study, a mechanistic model of cutting force components in up and down end milling process is presented. Using this cutting force model of 4-tooth endmills with various helix angles, cutting force variation of inconel 718 has been predicted. Predicted values of cutting force components are coincide well with the measured ones. As helix angle increases, overlapping effects of the active cutting edges increase. In up endmilling the magnitudes of radial and feed cutting force componts FX and FY are lowest when the helix angle is $40\{\circ}$, but in down endmilling the magnitudes of these values increase slightly as helix angle becomes large.

• Journal of Power System Engineering
• /
• v.19 no.2
• /
• pp.15-21
• /
• 2015

Bollard installed on the street is a facility that protects pedestrians by restraining cars from entering on the sidewalk. It is basically classified into manual, semiautomatic, automatic type and mostly manual type is widely used because the automatic type is imported and much expensive. However, in case of manual handling type in practice, it is very troublesome and difficult to remove it whenever cars are permitted, and in case of automatic type, since underbody of a bollard is very long, it is difficult to dig a deep hole in the ground because a pipe, a hose or a cable is under the surface. In order to reduce these difficulties, this paper proposed new design of the multistage bollard that moves up and down automatically by using hydraulic system. This is developed by 6 step creativity of TRIZ inventive problem solving and structural analysis. The developed bollard can be installed in shallow hole and allow entry of vehicles through up-and-down movement without its removal manually. Finally, we could see smoothly motion through the manufactured bollard.