• Title, Summary, Keyword: Phase difference

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Impacts of Korean Somatotype in Energy Consumption and Hormone Changes During Treadmill Gait -Around University Students-

  • Choi, Yoo-Rim;Choi, Wan-Suk
    • The Journal of Korean Physical Therapy
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    • v.23 no.6
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    • pp.85-92
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    • 2011
  • Purpose: This study is executed to examine the effects of Korean somatotype on energy consumption and hormone changes during treadmill gait. Methods: The objects of study were a total of 70 university students in their 20s and 30s divided into 7 groups according to somatotype with 10 members each, 4 groups of male (M1, M2, M3, M4) and 3 groups of female (F1, F2, F3). Results: In case of male groups, there was a significant difference in VO2 and VCO2 between group M1, M2 and M3 (p<0.05). There was also a meaningful difference between Phase1 and Phase2, Phase3 and Phase4 in a phase (p<0.01). In case of female groups, there was a meaningful difference in VO2 between F1 and F2, F3 (p<0.01). There was also a significant difference between Phase1 and Phase2, Phase3 and Phase4 in a phase (p<0.01). There was no significant difference in VCO2 among them, but there was a significant difference in it between Phase1 and Phase2, Phase3 and Phase4 (p<0.01). There was equally no significant difference in the concentration of adrenaline and nor-adrenaline among both male and female groups, but such concentration showed meaningful difference before and after exercise (p<0.01). Conclusion: Energy consumption differs according to somatotype. There is a difference in hormone change, indicating that somatotype has effects on the physiological change. Therefore, in future exercise should be executed in more diverse conditions to further study somatotype with energy consumption and the correlations of hormone change.

The Frequency-Speed Characteristics of Ultrasonic Motor by the Change of Phase difference (위상차 변화에 따른 초음파 모터의 주파수-속도 특성)

  • Kim D.O.;Jung G.Y.;Oh G.K.;Kim Y.D.
    • Proceedings of the KIPE Conference
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    • pp.146-149
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    • 2003
  • To control the position, velocity and torque of the ultrasonic motor, a great variety of method are proposed such as the amplitude, phase difference, frequency and so on. In the case of phase difference method, it has some advantages: it can control the direction and velocity of rotation only adjusting the phase difference and it has wide control-band. During the USM driving on adjusting phase difference, its characteristic was transformed by the change of resonance-frequency of stator, which means that the resonance frequency is different according to the phase difference. Consequently, we need to set up the most suitable driving frequency according to each phase difference.

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Development of Compact Phase-difference Controller for an Ultrasonic Rotary Motor (회전형 초음파모터의 소형 위상차 제어기 개발)

  • Yi Dong-Chang;Lee Myoung-Hoon;Lee Eu-Hark;Lee Sun-Pyo
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.8
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    • pp.64-71
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    • 2006
  • In this paper, a uniform speed controller for an ultrasonic rotary motor is developed using the phase-difference method. The phase difference method uses traveling waves to drive the ultrasonic motor. The traveling waves are obtained by adding two standing waves that have a different phase to each other. A compact phase-difference driver system is designed and integrated by combining VCO(Voltage Controlled Oscillator) and phase shifter. Theoretically the relationship between the phase difference in time and the rotational speed of the ultrasonic motor is sine function, which is verified by experiments. Then a series of experiments under various loading conditions are conducted to characterize the motor's performance that is the relationship between the speed and torque. Proportional-integral control is adopted for the uniform speed control. The proportional control unit calculates the compensating phase-difference using the rotating speed which is measured by an encoder and fed back. Integral control is used to eliminate steady-state errors. Differential control for reducing overshoot is not used since the response of ultrasonic motor is prompt due to its low inertia and friction-driving characteristics. The developed controller demonstrates reasonable performance overcoming disturbing torque and the changes in material properties due to continuous usage.

A Estimation of Contamination Degree by the Measurement of Phase Difference on the Outdoor Insulator (옥외절연물의 오손도 파악을 위한 위상차 측정)

  • 심규일;이원영;한상옥;박강식
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.443-446
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    • 2002
  • In this paper, a phase difference of liveline insulator was measured and analyzed to estimate the contamination degree. The probability of accident rises according to the increase of the contamination. So the estimation of contamination degree is very important in design and maintenance of outdoor insulator. There are many methods to measure the contamination degree, but those methods use the spacial sense to measure the contamination degree. So, we have no information about the contamination from the liveline insulator, but there is a measurement of phase difference to estimate the contamination degree. The phase difference is varied with the increase of ESDD, so the contamination degree could be estimated by using those characteristics. The experiment is performed to analyze the interrelationship between contamination degree and phase difference. The variable condition is relative humidity that increases from 30 to 100 % in a chamber. We use the DAS program to measure and analyze the data. From the result, the variation of phase difference is different by the contamination degree, so we can confirm the possibility of estimating the contamination degree by the phase difference.

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The Study on Highly Miniaturized Active 90°C Phase Difference Power Divider and Combiner for Application to Wireless Communication (무선 통신 시스템 응용을 위한 초소형화된 능동형 90°C 위상차 전력 분배기와 결합기에 관한 연구)

  • Park, Young-Bae;Kang, Suk-Youb;Yun, Young
    • Journal of the Korean Society of Marine Engineering
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    • v.33 no.1
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    • pp.144-152
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    • 2009
  • This paper propose highly miniaturized active $90^{\circ}C$ phase difference power divider and combiner for application to wireless communication system. The conventional passive $90^{\circ}C$ power divider and combiner cannot be integrated on MMIC because of their very large circuit size. Therefore, the highly miniaturized active $90^{\circ}C$ phase difference power divider and combiner are required for a development of highly integrated MMIC. In this paper, the highly miniaturized active $90^{\circ}C$ phase difference power divider and combiner employing InGaAs/GaAs HBT were designed, fabricated on GaAs substrate. According to the results, the circuit size of fabricated active $90^{\circ}C$ phase difference power divider and combiner were $1.67{\times}0.87$ mm and $2.42{\times}1.05$ mm, respectively, which were 31.6% and 2.2% of the size of conventional passive branch-line coupler. The output gain division characteristic of proposed divider circuit showed 8.4 dB and 7.9 dB respectively, and output phase difference characteristic showed $-89.3^{\circ}C$. The output gain coupling characteristic of proposed combiner circuit showed 9.4 dB and 10.5 dB respectively, and output phase difference characteristic showed $-92.6^{\circ}C$. The highly miniaturized active $90^{\circ}C$ phase difference power divider and combiner exhibited good RF performances compared with the conventional passive branch-line coupler.

Fatigue Crack Initiation around a Hole under Out-of-phase Biaxial Loading (이상 이축 하중 하에서 구멍 주위에서의 피로 균열 발생)

  • Huh, Yong-Hak;Park, Pi-Lip;Kim, Dong-Jin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.10
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    • pp.1695-1702
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    • 2003
  • Fatigue crack initiation around a hole subjected to biaxial fatigue loads with a phase difference was investigated. Axial and torsional biaxial fatigue loads with different phase differences and biaxiality of 1/√3 were applied to thin-walled tubular specimens. Five phase differences of 0, 45, 90, 145 and 180 degrees were selected. Directions of the fatigue crack initiation around the hole were found to approach to the circumferential direction of the specimen with increment of the phase difference for fatigue tests with phase differences less than 90$^{\circ}$. Whereas directions for tests with phase differences greater than 90$^{\circ}$ got away from the circumferential direction and those were symmetric to the directions for tests with phase difference less than 90. . Furthermore, it was shown that the fatigue initiation life decreased with increment of phase difference for fatigue tests with phase differences less than 90$^{\circ}$, but it increased for tests with phase difference greater than 90$^{\circ}$. The crack initiation direction can be successfully explained by using the direction of the maximum tangential stress range obtained around the hole and at far-field.

A Phase-shifter for Regulating Circulating Power Flow in a Parallel-feeding AC Traction Power System

  • Choi, Kyu-Hyoung
    • Journal of Electrical Engineering and Technology
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    • v.9 no.4
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    • pp.1137-1144
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    • 2014
  • A parallel-feeding AC traction power system increases the power supply capacity and decreases voltage fluctuations, but the circulating power flow caused by the phase difference between the traction substations prevents the system from being widely used. A circuit analysis shows that the circulating power flow increases almost linearly as the phase difference increases, which adds extra load to the system and results in increased power dissipation and load unbalance. In this paper, we suggest a phase shifter for the parallel-feeding AC traction power system. The phase shifter regulates the phase difference and the circulating power flow by injecting quadrature voltage which can be obtained directly from the Scott-connection transformer in the traction substation. A case study involving the phase shifter applied to the traction power system of a Korean high-speed rail system shows that a three-level phase shifter can prevent circulating power flow while the phase difference between substations increases up to 12 degrees, mitigate the load unbalance, and reduce power dissipation.

A Fractional-N PLL with Phase Difference-to-Voltage Converter (위상차 전압 변환기를 이용한 Fractional-N 위상고정루프)

  • Lee, Sang-Ki;Choi, Young-Shig
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.16 no.12
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    • pp.2716-2724
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    • 2012
  • In this paper, a Phase Difference-to-Voltage Converter (PDVC) has been introduced into a conventional fractional-N PLL to suppress fractional spurs. The PDVC controls charge pump current depending on the phase difference of two input signals to phase frequency detector. The charge pump current decreases as the phase difference of two input signals increase. It results in the reduction of fractional spurs in the proposed fractional-N PLL. The proposed fractional-N PLL with PDVC has been designed based on a 1.8V $0.18{\mu}m$ CMOS process and proved by HSPICE simulation.

Pointing position detection of capacitive touch screen panel using phase-difference method (위상차 방식을 사용한 용량방식 터치 스크린 패널의 접촉 위치 검출)

  • Jo, Yeong-Cheol;Jang, Rae-Hyeok;Gwon, Uk-Hyeon
    • Journal of Institute of Control, Robotics and Systems
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    • v.4 no.3
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    • pp.406-412
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    • 1998
  • This paper describes a contact position detection method of a capacitive touch screen panel. The proposed method is composed of a circuited compensating algorithm generating an output signal having phase difference to an input signal associated with contact position, converts both input and output signals into digital waveform (5V logic), and calculates the phase difference. Finally, position information with the phase difference is obtained by using a low-cost microprocessor, which is convenient to compensate non-linearity error. The proposed method, that computes phase difference directly, has advantages in feasibility and cost because it minimizes the use of analog devices; rather, it utilizes, cost effective digital circuit. Analytical results are also given.

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Characteristics of Ultrasonic Motor using Voltage Control and Phase Difference Control (초음파 모터의 전압 및 위상차 제어 특성)

  • Shin, Duk;Kim, Dong-Ok;Ko, Nak-Yong;Choi, Han-Soo;Kim, Young-Dong
    • Proceedings of the KIEE Conference
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    • pp.949-952
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    • 1996
  • The ultrasonic motor(USM) has good characteristics such as compact size, silent motion, low speed, high torque and high speed response. The USM is driven by 2-phase AC electricity. The control parameters of USM are voltage, phase difference, frequency of input power, etc. In this paper, we propose voltage difference control. And we designed USM controller to adjust voltage and phase using pLSI(programmable Large Scale Integration). Voltage difference control has many advantages that are lower current, lower power than phase difference control. Especially there is nearly zero ampere at the zero point of speed and torque. we can apply this voltage difference control to the compliance control of DD manipulator.

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