• Journal of Drive and Control
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• v.17 no.3
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• pp.47-56
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• 2020

As a shift control of automatic transmission was managed with the electronic control unit (ECU), shift quality which is a measure of shift shock during gear change has markedly improved. However, the initial clutch pressure control of the clutch filling phase should continue to rely on the predetermined control input since the input and output speeds are unchanged until the shifting process attains the inertia phase. It is critical to minimize the clutch response time and control the clutch pressure accurately at the end of clutch fill to achieve quick shift response and smoothness. Advanced transmission companies have adopted an auto calibration method which establishes the databases for the clutch piston fill-up attributes and the frictional characteristics of the disks. In this study, a distinctive auto calibration algorithm for forklift transmission under development is proposed and verified with the real-vehicle test. The experimental calibration results showed consistent turbine dynamics at the initial stage of shifts with the properly calibrated clutch-fill control parameters. By using this technique, it is necessary to finalize the shift control for the various operation conditions.

• KIEE International Transactions on Power Engineering
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• v.5A no.3
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• pp.293-299
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• 2005

Automatic reclosing is a typical protection method in power distribution systems for the clearing of temporary faults. However, it has a fatal weakness in regards to voltage sags because it produces repetitive voltage sags. In this paper, we explored the repetitive impact of voltage sag due to the automatic reclosing of power distribution systems. The actual tests of low voltage loads were carried out for obtaining the susceptibility of voltage sags. The final results of the tests yielded power acceptability curves of voltage sag, and the curves transformed the 3-dimensional CBEMA (Computer Business Equipment Manufacturer Association) format. For the quantitative evaluation of the impact of repetitive voltage sags, an assessment formulation using the voltage sag contour was proposed. The proposed formulation was tested by using the voltage sag contour data of IEEE standard and the results of the test. Through the case studies, we verified that the proposed method can be effectively used to evaluate the actual impact of repetitive voltage sags.

• Journal of Drive and Control
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• v.19 no.2
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• pp.17-26
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• 2022

Recently, automatic transmissions caused a good improvement in the shift quality of a forklift. An advanced shift control algorithm, which was based on TCU firmware, was applied with embedded control technology and microcontrollers. In the clutch-to-clutch shifting, one friction element is released and the other friction element is activated. During this process, if the release and application timings are not synchronized, an overrun or tie-up occurs and ultimately leads to a shift shock. The TCU, which measures only the speed of the forklift, inevitably applies the open-loop shift control. In this situation, the speed ratio does not change during the clutch fill. The torque phase occurs until the clutch is disengaged. In this study, an offline shift logic of the learning control was proposed. It induced a synchronous shift when the learning control progressed. During this process, the reference current trajectory of the release clutch was corrected and applied to the next upshift. We considered the results of the overrun/tie-up characteristics of the upshift performed immediately before. The vehicle test proved that the deviation in shift quality, which was caused by the difference in the mechanical characteristics of the clutch, could be improved by the learning control.

• Journal of Drive and Control
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• v.20 no.4
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• pp.17-26
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• 2023

A forklift is an industrial vehicle that lifts or transports heavy objects using a hydraulically operated fork, and is equipped with an automatic transmission for the convenience of repetitive transportation, loading, and unloading work. The Transmission Control Unit (TCU) is a key component in charge of the shift control function of an automatic transmission. It consists of an electric circuit with an input/output signal interface function and firmware running on a microcontroller. To develop TCU firmware, the development process of shifting algorithm design, firmware programming, verification test, and performance improvement must be repeated. A simulator is a device that simulates a mechanical system having dynamic characteristics in real time and simulates various sensor signals installed in the system. The embedded transmission simulator is a simulator that is embedded in the TCU firmware. information related to the mechanical system that is necessary for TCU normal operation. In this study, an embedded transmission simulator applied to the originally developed forklift TCU firmware was designed and used to verify various forklift shift control algorithms.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.64-67
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• 2000

It is usual that the medical examination of human body need special knowledpe and equipments. Thus we have to spend Lime and energy on going to special place such as hospital where doctors and equipments are. Which often cause missing a good chance af medical treatment as well as giving us inconvenience. However many simple and convenient equipments were developed for checking our health conditions recently. O-ring test is accepted a3 one of useful methods to examine our heallb conditions. Also the test is recognized as a uscful means to judge, withoul any special equipment and medical knowledge, if some medical substances or foods are beneficial or harmful to our health. However, the judgement may be mcorrect because it depend on doctor's subjective point of view.In this study, we developed an automatic O-ring t a r mach~ne which enable us to check our health conditions objectively and quantitatively. The validity of the idea to develope the machine was proved by experiments.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.235-238
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• 2002

In this paper we describe the design and implementation of Electrical Ground Support Equipment(EGSE) for the CBS transponder testing. The main task of EGSE is to check out satellite systems, at system or subsystem level, during integration and validation phases of their life-cycle. Through a combination of hardware and software elements, EGSE supports manual, semi-automatic and fully automated testing. Automation is achieved by offering users simple, yet powerful means to write their own test application programs (test sequences) in high-level, test-oriented language and to run them in a strict real-time environment. The core of this environment is a user-configurable real-time database, containing all the information needed to calibrate acquired data, check them against predefined thresholds, automatically react to out-of-range conditions, display data using animated graphics or synoptic windows, and so on.

• The Journal of the Korea Contents Association
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• v.18 no.11
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• pp.508-515
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• 2018

The purpose of this study was to analyze the errors of the built - in dose area product and the calibrated moving dose area product when using automatic exposure controller of the interventional equipment. And then, the importance of the dosimeter calibration and the necessity of the calibration guideline were investigated. The experimental method was to assemble the phantom into Thin, Normal, and Heavy Adult according to the NEMA Phantom manual and to measure the dose area with the built-in dose area product and the moving dose area product. As a result, in all thicknesses, the built-in dose area product showed higher doses than the moving dose area product, and the thicker the thickness, the larger the difference. In addition, paired t-test was performed for each item and there was a significant difference in each item between p<0.05. In conclusion, considering the intervention which is highly exposed to the radiation exposure, it is that we have to know the accurate dose when using the AEC of the equipment. And there is no calibration guide for the built-in dose area meter, thus calibration guidelines should be prepared.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.2324-2329
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• 2014

The inspection of distance to go train control system conducted only when train is in main line or inspecting line, that affects low work efficiency and hazard elements to safe operation. Before or after train operation, the interface test between on-board and wayside signal system must be conducted. In this paper, onboard signal interface inspection system based on the real-time automatic analysis of onboard system status information that is transmitted to the wayside system and the operation status check of the onboard signal device operates as a virtual train information that is transmitted to the onboard system have been proposed. And after building the inspection system to the inspecting track of Daejeon Subway Line 1, Panam Depot, the verification algorithm of proposed interface test and the results was presented. therefore, it has enhanced work efficiency to do not carry train operation of a half hour in test line to test on-board system.

• Journal of the Korean Institute of Telematics and Electronics
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• v.18 no.3
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• pp.52-57
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• 1981

This paper deals with the development of a design approach to generate easily testable complex digital systems. As the technique is based on small testable building blocks (submodule) with the exhaustive testing circuits, it is not necessary for any automatic test equipment and signature analyzer. As a result ,the test time which is determined not by circuit complexity but sixte of the tarprest submodule, is not exhaustive and also, the circuit reliability is very high.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.469-476
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• 2001

The Ν-value in the standard penetration test(SPT) is affected by the magnitude of the rod penetration energy transmitted from the falling hammer as well as the geotechnical characteristics of the ground. Understanding of the striking energy efficiency in the SPT equipment is getting important for that reason. The energy efficiencies of the doughnut hammer with the hydraulic lift system and the automatic trip hammer system were investigated through field tests using the instrumented rod and wave-signal acquisition systems including the pile driving analyzer(PDA) . The rod energy ratio, ΕR$\_$r/ was defined as the ratio of the energy delivered to the drilling rod to the potential free-fall energy of the hammer. It appears that the type of the hammer and lift/drop system had a strong influence on the energy transfer mechanism and ΕR$\_$r/ also varies according to the energy instrumentation system and the analysis methods.