• Journal of Magnetics
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• v.20 no.2
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• pp.114-119
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• 2015

This study explored the effect of pulsed magnetic field (PMF) stimulus on the improvement of blood stagnation by means of photoplethysmography (PPG). Our stimulus system was designed to generate PMF with a maximum intensity variation of 0.20 T at a transition time of $160{\mu}s$, with pulse intervals of 1 Hz. In order to quantitatively estimate vascular condition, indices such as blood vessel tension (BVT), stress power (SP), differential pulse wave index (DPI) and remained blood volume (RBV) were calculated from the second derivative of the PPG signal and power density spectrum (PDS). Our results showed that non-invasive PMF stimulus was effective in improving blood stagnation. Therefore, it may be concluded that appropriate PMF stimulus affects the blood circulatory system.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.173-179
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• 2004

Breakup characteristics of liquid sheets formed by the impingement of two water jets, such as a breakup length and a breakup wavelength of sheet, were investigated as increasing the injection velocity up to 30m/s and the ambient gas pressure up to 4.0㎫. While round edged orifices formed a laminar sheet which has no waves on the sheet when the injection velocity is low, sharp edged orifices formed a turbulent sheet which has impact waves irrespective of the injection velocity. Thus we compared the differences of breakup characteristics between them. The results showed that the aerodynamic force significantly affects the breakup of laminar sheet when the gas based Weber number is higher than unity. It was also found that the turbulent sheets have three breakup regimes, i.e. expansion regime, wave breakup regime and catastrophic breakup regime according to the gas based Weber number.

• Journal of the Korean Geophysical Society
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• v.4 no.3
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• pp.163-173
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• 2001

This paper deals with scheduling problems which are the most important subtask in High-Level Synthesis. Especially, we have concentrated our attentions on the data-path scheduling which can get the structural informaion trom the behavioral algorithm as a first step in synthesis procedure. Suggest Forward scheduling methode is executed the ASAP and ALAP scheduling to use the fifth - order elliptic wave filter of a standard benchmark moedl, and then it is drawing up T.N matrix table by the number resource and control-step, using the table extract of the simple than down-limit value of the control-step for the number of given resource th use this table. All of existing list scheduling techniques determine the priority function first, and then do the operation scheduling, But, the suggested forward scheduling technique does the schedule first, and determines the priority functions if needed in scheduling process.

• International Journal of Railway
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• v.1 no.4
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• pp.169-174
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• 2008

Experimental study has been conducted to clarify the internal and external pressure variation characteristics for KTX(Korea Train eXpress) passing through tunnel. Abrupt pressure variation gives rise to the ear-discomfort for passenger and fatigue for car body. In this study, the internal and external pressure variation are measured by using KTX real train experiment and on-board portable data acquisition system in Gyeongbu high speed commercial line. The tunnels from 200 m to 4000 m in length are chosen for the investigation of tunnel length effects. From the results of experiment, the internal pressure variation rate for all the test tunnels is lower than the standard criteria of 200 Pa/s. And, the critical tunnel lengths for pressure wave pattern are classified into 7 groups by using the theoretical L-t diagram analysis.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.5
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• pp.492-501
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• 1992

In this paper, an ion analyzer is used in conjunction with a Langmuir probe to study the chracteristics of ECR plasma such as the ion temperature, ion current density and electron temperature as the operating pressure, ${\mu}$-wave power and axial position change, Silicon etching has been performed with RF-biasing and its etching chracteristics have been discussed in terms of the ion energy distribution function. The maximum value of ion current density appears in the range of 10S0-3T mbar and the broadening of ion energy distribution function increases as pressure increases. Therefore, as pressure decreases, anisotropy increases but selectivity to photoresist decreases.

• Journal of Ocean Engineering and Technology
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• v.15 no.1
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• pp.26-30
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• 2001

Up to now, Most studies of hydroelasticity are about frequency domain analysis. Those aren't suited for analysis of the landing take-off, and dropping of aircraft on a structure. So, the concern of this paper is the transient behavior of a VLFS subjected to dynamic load, induced by airplane landing and take-off. To predict the added mass, damping coefficient, and wave exciting force, the source-dipole distribution method was used in the frequency domain. The responses are accomplished by using the FEM scheme. A time domain analysis method is based on the Newmark β method to pursue the time step procedure, taking advantage of memory effect function for hydrodynamic effects.

• Proceedings of the KIEE Conference
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• 2007.04b
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• pp.169-171
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• 2007

We studied the partial discharge detecting by sensing electromagnetic wave emitted from the partial discharge source in the HV Rotating Machine with the new prototype patch antenna sensor. In this study, we design new type of patch antenna based on microstrip technology and make many experiments of elaine testing compare with the existing HFCT and EM probe on stator winding of HV generator in the laboratory. This paper will mention comparison of experimental results based on the three kinds of sensors.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2009.10a
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• pp.132-133
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• 2009

부산 수영만 해상케이블카 설치예정수역에서 파랑 및 유동환경에 대한 기본 자료 조사와 아울러 대상해역에서 구조물을 설치하였을 때 주요 입사파에 대한 파랑 및 유통환경 변화 특성을 수치모텔 시뮬레이션으로 분석하여 타당성을 검토하고자 하였다. 대상해역에서 광안대교가 설치된 조건이나 이의 외해측으로 일련의 해상케이블 지지구조물을 설치함에 따라 발생할 수 있는 환경 중 해저저질의 이동 및 표사에 영향을 미치는 파랑과 유동장 해석을 대상으로 하였다. 파랑해석은 SWAN 모델을 이용하여 분석하였고, 유동장 해석은 MIKE21 HD 모듈을 이용하여 해석하였다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.7
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• pp.770-775
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• 2004

Although $High-T_c $superconducting HTS antennas have high efficiency and high gain, narrow bandwidth due to the high Q is the major limitation for application of satellite communication and mobile communication. Defining bandwidth as the frequency range over which standing wave ratio (SWR) is 2:1 or less, HTS antenna bandwidths are typically less than 1 %. Thus considerable effort has been focused on developing HTS antennas for broadband operation. In this work the HTS antenna array, using the bipin antenna which consisted of two triangle-radiation patches, was designed and fabricated using a ${YBa}_2{Cu}_3{O}_7x (YBCO)$ superconducting thin film on a MgO substrate for broadband operation. Also gold antennas with the same dimension as our HTS antennas were fabricated on the MgO substrate for the comparison. Experimental results for both antennas were reported in terms of radiation patterns, return losses, bandwidths and other various characteristics. The center frequency of HTS antennas was 20.28 GHz and the bandwidth obtained was significant 10 %.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05a
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• pp.26-29
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• 2002

The ramp waveform has recently been introduced to erase wall charges of the previously selected cells for plasma display. However. the ramp waveform can't completely remove wall charges. In this paper. we suggested new erase waveform having a complex with close width pulse and ramp pulse for complete erasing. The erasing margin of suggested waveform is wider than the conventional waveform. Moreover. suggested wave form can reduce the erasing time compared.