• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.4
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• pp.18-26
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• 2001

In this paper, we propose an ATC(Automatic Transfer mode Controller) algorithm and an average-mode-change method for use in Gear shift PLL which can automatically change loop gain. The proposed ATC algorithm accurately detects proper timing or the mode change and has a very simpler structure - than the conventional lock detector algorithm often used in QPSK. And the proposed average mode change method can obtain low errors of estimated frequency offset by averaging the loop filter output of frequency component in shift register. These algorithms are also useful in designing ASIC, since these algorithms occupy small circuit area and are adaptable for high speed digital processing. We also present phase tracking performance of proposed Gear-shift PLL, which is composed of polarity decision PD, ATC and average mode change circuit, and analyze the results by examining constellation at each mode.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.229-232
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• 2009

DC-shift phenomenon can be observed in Hybrid rocket combustion. This phenomenon makes performance drop which is structure problem or reduce thrust. Understanding of DC-shift phenomenon, the conditions of the hybrid rocket combustion stability can be found. In this paper, the condition of DC-shift was found and made by using acoustic mode and vortex shedding frequency. The conditions of stable combustion was defined from the experimental study of DC-shift phenomenon.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.1
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• pp.199-202
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• 2009

Scan design is currently the most widely used structured Design For Testability approach. In scan design, all storage elements are replaced with scan cells, which are then configured as one or more shift registers(also called scan chains) during the shift operation. As a result, all inputs to the combinational logic, including those driven by scan cells, can be controlled and all outputs from the combinational logic, including those driving scan cells, can be observed. The scan inserted design, called scan design, is operated in three modes: normal mode, shift mode, and capture mode. Circuit operations with associated clock cycles conducted in these three modes are referred to as normal operation, shift operation, and capture operation, respectively. In spite of these, scan design methodology has defects. They are power dissipation problem and test time during test application. We propose a new methodology about scan shift clock operation and present low power scan design and short test time.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.2
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• pp.222-228
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• 2014

As tightened the grid connection related regulation for a distributed power generation Japan, islanding of the distributed power generation should be detected more rapidly. In this paper, it is introduced the development tendency of sliding mode frequency shift type anti-islanding technology in Japanese companies.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.05a
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• pp.100-103
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• 2005

Homogeneously aligned nematic liquid crystal modes are representatively the -FFS (fringe-field switching) mode using liquid crystal (-LC) with negative dielectric anisotropy, the +FFS mode and the IPS (in-plane switching) mode using +LC with positive dielectric anisotropy. In view of image quality evaluation standard of LCD, we compared characteristics of the brightness, the contrast ratio (CR) and color shift when the modes have respectively optimized phase retardation values $(d{\Delta}n)$. Consequently, in the most sensitively viewing angle of a man's physical vision, both FFS modes have advantage over the IPS mode from the brightness & the CR point of view. We are also confirmed that the +FFS mode out of them shows the smallest color shift according to all viewing directions in grey levels.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.361-364
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• 2008

In this paper, several fields for improving shift quality and mode conversion quality are presented and considered. For a series type hybrid vehicle, improving mode conversion quality is important because it changes its speed with its own motors. A parallel type hybrid vehicle usually has AT or AMT, and its motor and engine can work independently. Therefore, improving both of two qualities is equally important in this case. For a power split type hybrid vehicle, improving mode conversion quality is more important due to the existence of planetary gears which change vehicle's speed.

• Journal of Information Display
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• v.8 no.3
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• pp.17-21
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• 2007

We introduce a new electrode structure for the patterned vertical alignment (PVA) mode, which has a lower color-shift at large viewing angle than the one-domain VA mode. By manipulating the period of electrode structure, we can make more multi-domains and use the existing fabrication processes without having to use additional materials.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.7
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• pp.458-461
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• 2005

Power dissipated during test application is substantially higher than power dissipated during functional operation which can decrease the reliability and lead to yield loss. This paper presents a new technique for power minimization during test application in full scan sequential circuits. This paper shows freezing of combinational logic parts during scan shift operation in test mode. The freezing technique leads to power to minimization. Significant power reduction in the scan techniques is achieved on ISCAS 89 benchmarks.

• Smart Structures and Systems
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• v.9 no.6
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• pp.549-563
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• 2012

Theoretical analysis is performed on a multi-mode energy harvester design with focus on the first two vibration modes. Based on the analysis, a modification is proposed for designing a novel adaptive multi-mode energy harvester. The device comprises a simply supported beam with distributed mass and piezoelectric elements, and an adaptive damper that provides a 180 degree phase shift for the motions of two supports only at the second vibration mode. Theoretical analysis and numerical simulations show that the new design can efficiently scavenge energy at the first two vibration modes. The energy harvesting capability of the multi-mode energy harvester is also compared with that of a cantilever-based energy harvester for single-mode vibration. The results show that the energy harvesting capacity is affected by the damping ratios of different designs. For fixed damping ratio and design dimensions, the multi-mode design has higher energy harvesting capacity than the cantilever-based design.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.1
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• pp.90-98
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• 2005

HMT is a type of continuously variable transmission which has split power flow path characteristics with gear train and hydro static unit. The benefit of improved fuel economy and high power capacity enables it to be a promising application fur large vehicles. This paper presents the analysis results including velocity, static torque, transmission efficiency and dynamic model of the HMT that is developed for city buses. The speeds or gear shafts, the static clutch torque and split power ratio for each mode are detailed here. From the analysis of HMT transmission efficiency considering the power loss in meshed gear and hydraulic unit, we can conclude that minimization of hydraulic power is necessary for improved fuel economy design. Also, the dynamic simulation result for mode shift characteristics shows that little shift shock is observed because of the synchronized rotation speed in clutch.