• The Journal of Korean Society for Radiation Therapy
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• v.26 no.1
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• pp.37-42
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• 2014

Purpose : At the time of the pelvis cancer radiation treatment using the belly board, set-up error is large because of a prone position. In order to improve the reproducibility, we made Vac-lock type belly board. In this study, we attempt to validate its utility. Materials and Methods : We compared belly board and Vac-lock type belly board through the OBI. OBI was performed three times with entire course of treatment and the setup errors in the direction of X axis, Y axis, Z axis were recorded and calculated the distance from the isocenter. Results : X axis, Y axis, Z axis setup errors with existing belly board were 0.32 cm, 0.41 cm, 0.29 cm. The setup errors with the vac-lock type belly board were 0.12 cm, 0.19 cm, 0.17 cm. Further, errors of 0~0.29 cm were increased from 48% to 83% when using VLT belly board. Error of 0.5 cm or more was reduced from 21% to 2%. Conclusion : Vac-lock type belly board is able to maintain the efficacy of existing and create to match the characteristics of the patient. Therefore We think that vac-lock type belly board is very useful in pelvic cancer patients.

• Transactions on Electrical and Electronic Materials
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• v.6 no.4
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• pp.159-163
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• 2005

We analyzed the fault current limiting characteristics of a flux-lock type $high-T_c$ super­conducting fault current limiter (HTSC-FCL) using series resonance between capacitor for series resonance and magnetic field coil which was installed in coil 3. The capacitor for the series resonance in the flux-lock type HTSC-FCL was inserted in series with the magnetic field coil to apply enough magnetic field into HTSC element, which resulted in higher resistance of HTSC element. However, the impedance of the flux lock type HTSC-FCL has started to decrease since the current of coil 3 exceeded one of coil 2 after a fault accident. The decrease in the impedance of the FCL causes the line current to increase and, if continues, the capacitor for the series resonance to be destructed. To avoid this operation, the flux-lock type HTSC-FCL requires an additional device such as fault current interrupter or control circuit for magnetic field. From the experimental results, we investigated the parameter range where the operation as mentioned above for the designed flux-lock type HTSC-FCL using series resonance occurred.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.515-518
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• 2001

In this study, the electric door lock using the password input system for security improvement was fabricated. The security has been improved by using the multiple micro process. The controller with solenoid valve has been designed indirect driving system for releasing the door lock system. Also, the self checkup system for improving the trustworthy was developed with two kinds of micro process. The results will be applied IC card system and fingerprint identification system for security improvement.

• Proceedings of the IEEK Conference
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• 2001.06b
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• pp.281-284
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• 2001

This paper describes an analog multi-phase delay-locked loop (DLL) to solve the harmonic lock problem using current-starved inverter and shunt-capacitor delay cell. The DLL can be used not only as an internal clock buffer of microprocessors and memory It's but also as a multi-phase clock generator for gigabit serial interfaces. The proposed circuit was simulated in a 0.25${\mu}{\textrm}{m}$ CMOS technology to solve harmonic lock problem and to realize fast lock-on time and low-jitter we verified time interval less than 40 ps as the simulation results.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.6
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• pp.1353-1361
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• 2001

Vortex lock-on or resonance behind a circular cylinder is visualized using a time-resolved PW when a single frequency oscillation is superimposed on the mean incident velocity. For vector processing, a cross-correlation algorithm in conjunction with a recursive correlation and interrogation window shifting techniques is used. Measurements are made of the Karmas and streamwise vertices in the wake-transition regime at Reynolds lumber 360. When lock-on occurs, the vortex shedding frequency is found to be half the oscillation frequency as expected from previous experiments. At the lock-on state, the Karman vortices are observed to be more disordered by the increased strength and spanwise wavelength of the streamwiee vortices, which lead? to a strong three-dimensional motion.

• Journal of the Korea Society of Computer and Information
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• v.4 no.2
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• pp.105-112
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• 1999

Spread Spectrum Communication is a core technique in CDMA system, but the problem for SS Communication schemes is synchronous method. There are DLL(Delay Lock Loop), Tau-dither Loop, SO(Synchronous Osillator) etc., in the sychronous method. But since there are analog operations, the setting is difficult and circuit size is large. In this paper we proposed Digital Delay Lock Loop (DDLL) and estimated it's performance through the experiment.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.2
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• pp.198-201
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• 2008

We investigated the operating characteristics of the flux-lock type superconducting fault current limiter(SFCL) with the parallel connection between the primary and secondary windings which are connected with two superconducting units in series. The parallel connection for current level increase of the flux-lock type SFCL is necessary to apply the SFCL into the power system. The resistance generated in superconducting units was dependent upon the winding direction of the primary and the secondary coils, which can reduce the power burden. The resistance of the superconducting elements in the subtractive polarity winding is higher than that of the additive polarity winding. The fault current limiting effect of the subtractive polarity winding is better than that of the additive polarity winding. From this results, we confirmed that the power capacity of the flux-lock type SFCL could be increased by the parallel connection of the superconducting units.

• Journal of Industrial Technology
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• v.18
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• pp.355-362
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• 1998

The deadlock detector is a DBMS sub-component that examines periodically whether system is in a deadlock state based on lock waiting information of transactions. The deadlock detector and transactions execute concurrently in a DBMS and read and/or write the lock waiting information simultaneously. Since the lock waiting information is a shared one, we need an efficient method guaranteeing its physical consistency by using mutual exclusion. In this paper, we propose a new method that effectively guarantees physical consistency of lock waiting information. Two primary goals of our method is to minimize the processing overhead and to maximize system concurrency.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.1865-1870
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• 2014

Torque converter is a complex turbomachine used to transfer power smoothly from an engine to a transmission by lock-up clutch. A torque converter consists of the hydrodynamic clutch device and the lock-up clutch device. The retaining plate and driven plate are part of the lock-up clutch. The lock-up clutch connects directly to achieve the improvement of efficiency and fuel consumption. In this paper, using structure analysis of stress distribution on the shape of the mechanical stopper on retaining plate. The shape of mechanical stopper has effect on the stress distribution of lock-up clutch.

• Journal of the Korea institute for structural maintenance and inspection
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• v.4 no.3
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• pp.197-204
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• 2000

Tensile strength (stress) of bar splice is important in the research of mechanical behavior of reinforced concrete structures-beam, column etc.- with bar splice. The purpose of this research is to evaluate the flexural behavior - deflection of beam specimens, strain of main bars - of reinforced concrete beam with Lock Joint Coupler. To make a comparative research, reinforced concrete beam specimens with normal deformed bar and lap splice are tested and analyzed. Test results, Comparing a deflection of three types flexural specimens, a flexural specimen with Lock Joint Coupler is 40% greater than the other flexural specimens. At the center of flexural specimen, the strain of main bar(D29) with lock joint coupler is 50% less, and vice versa, at the point of 14cm far from the center of flexural specimen, the strain of main bar(D29) with lock joint coupler is 9% larger than the strain of main bar(D29) which calculated using the classical flexure theory. A discords, between a deflection behavior of the flexural specimens and a strain of the main bar, are caused by the difference of strain between the lock joint coupler and main bar, near the lock joint coupler. So, additional research is need to verify as stated above discords.