• 제목/요약/키워드: Active Time

검색결과 5,038건 처리시간 0.034초

Formulating for efficacy

  • Johann W. Wiechers;Caroline L. Kelly;Trevor G. Blease;Chris Dederen
    • 대한화장품학회:학술대회논문집
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    • 대한화장품학회 2003년도 IFSCC Conference Proceeding Book I
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    • pp.457-468
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    • 2003
  • Active ingredients have been around in cosmetics for a long time but have they really resulted in active cosmetic products\ulcorner In order to achieve this, the right active needs to be delivered to the right location at the right concentration for the correct period of time. And the extent (and therefore the concentration) of this delivery depends on the formulation. From a rather theoretical approach based on the polarity of the active ingredient, the stratum corneum and the oil phase, the Relative Polarity Index was established that enables the selection of a suitable emollient for ensuring skin penetration of the active ingredient. Practical examples subsequently show the validity of this approach that demonstrates that one can regulate the delivery of an active molecule (and therefore the efficacy of a cosmetic formulation) by selection and control of the emollient system. Cosmetic formulations are generally quite complex mixtures and subsequent experiments using different emulsifier systems indicated that this component of a cosmetic formulation could also have an impact on steering the active ingredient to the right layer of the skin, although it is too early to be able to derive general rules from this.

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Pole Assignment for Structural Active Control

  • Vongchavalitkul, Sanguan
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2004년도 ICCAS
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    • pp.5-7
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    • 2004
  • Significant progress has been achieved in the active control of civil-engineering structures, not only in the control algorithm, but also in control testing of the scaled model and full-scale building. At the present time, most algorithms used in the active control of civil engineering structures are based on the various active control techniques. In this paper represents active control method, by using pole assignment for reducing structural vibration under excited load. Numerical simulations are performed to assess the effectiveness of pole assignment control system. The relative displacement of structure system is significantly reduced.

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Effect of feedback on PID controlled active structures under earthquake excitations

  • Nigdeli, Sinan Melih
    • Earthquakes and Structures
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    • 제6권2호
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    • pp.217-235
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    • 2014
  • In this paper, different feedback control strategies are presented for active seismic control using proportional-integral-derivative (PID) type controllers. The parameters of PID controller are found by using an numerical algorithm considering time delay, maximum allowed control force and time domain analyses of shear buildings under different earthquake excitations. The numerical algorithm scans combinations of different controller parameters such as proportional gain ($K_p$), integral time ($T_i$) and derivative time ($T_d$) in order to minimize a defined response of the structure. The controllers for displacement, velocity and acceleration feedback control strategies are tuned for structures with active control at the first story and all stories. The performance and robustness of different feedback controls on time and frequency responses of structures are evaluated. All feedback controls are generally robust for the changing properties of the structure, but acceleration feedback control is the best one for efficiency and stability of control system.

실시간 Hardware-in-the-Loop 시뮬레이션을 이용한 반능동 현가시스템 특성 평가 (A Strategy to Evaluate Semi-Active Suspension System using Real-Time Hardware-in-the-Loop Simulation)

  • 최규재;노기한;유영면;김혁
    • 한국자동차공학회논문집
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    • 제9권6호
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    • pp.186-194
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    • 2001
  • To meet the challenge of testing increasingly complex automotive control systems, the real-time hardware-in-the-loop(HIL) simulation technology has been developed. In this paper, a strategy for evaluation of semiactive suspension systems using real-time HIL simulation is presented. A multibody vehicle model is adopted to simulate vehicle dynamic motions accurately. Accuracy of the vehicle simulation results is compared to that of the real vehicle field test and proven to be very accurate. The controller and stepping motor to adjust semi-active damper stage are equipped as external hardwares and connected to the real-time computer which has vehicle dynamic model. Open and closed loop test methods are used to evaluate a controlled suspension system and the system's operations are verified it is found that the proposed evaluation methods can be used well for the verification of semi-active suspension systems.

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오래 달리기로 인한 피로가 지면반력 성분에 미치는 영향 (Effect of a Prolonged-run-induced Fatigue on the Ground Reaction Force Components)

  • 류지선
    • 한국운동역학회지
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    • 제23권3호
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    • pp.225-233
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    • 2013
  • The purpose of this study was to estimate the potential injury via analyzing ground reaction force components that were resulted from a prolonged-run-induced fatigue. For the present study, passive and active components of the vertical ground reaction force were determined from time and frequency domain. Shear components of GRF also were calculated from time and frequency domain. Twenty subjects with rear foot contact aged 20 to 30, no experience in injuries of the extremities, were requested to run on the instrumented tread-mill for 160 minutes at their preference running speed. GRF signals for 10 strides were collected at 5, 35, 65, 95, 125, and 155 minute during running. In conclusions, there were no significant difference in the magnitude of passive force, impact load rate, frequency of the passive and active components in vertical GRF between running times except the magnitude of active force (p<.05). The magnitude of active force was significantly decreased after 125 minute run. The magnitude of maximum peak and maximum frequency of the mediolateral GRF at heel strike and toe-off have not been changed with increasing running time. The time up to the maximum peak of the anteroposterior at heel-strike moment tend to decrease (p<.05), but the maximum peak and frequency of that at heel and toe-off moment didn't depend significantly on running time.

유비쿼터스 기반 통신의 철도구조물에 대한 재난감지용 능동형 데이터로거 시스템 연구 (A Study of Health & Disaster Monitoring Measurement using Ubiquitous Active Communication Digital Datalogger System for Railway Structures)

  • 이승원
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2011년도 춘계학술대회 논문집
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    • pp.470-475
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    • 2011
  • The objective of this study is the developement health & disaster monitoring measurement using ubiquitous active communication digital datalogger system for monitoring measurement of railway construction sites. For the replacement of current passive data communication, ubiquitous active communication digital datalogger system is studied for the first time with in a country. Therefore data communication method and analyzing program of automatic measurement data is developed for the global positioning automatic digital datalogger system. The results of this study will be using both real time automatic monitoring measurement and health & disaster monitoring measurement of railway structures.

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Sliding Mode Active Queue Management Algorithm

  • Roudsari, Farzad Habibipour;Jalili-Kharaajoo, Mahdi
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2004년도 ICCAS
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    • pp.227-231
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    • 2004
  • In this paper, a robust Sliding Mode Variable Structure (SMVS) controller is designed for Active Queue Management (AQM). This type of controller is insensitive to noise and variance of the parameters, thus it is suitable to time varying network systems. Simulation results conform the robust performance of SMVS controller against the disturbance. At the same time, a complete comparison between SMVS and PI controllers is made. The conclusion is that both transient and steady state performance of SMVS controller is better than that of PI one.

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THEORETICAL CONSIDERATIONS ON THE VARIABILITY OF ACTIVE GALACTIC NUCLEI

  • PARK SEOK JAE
    • 천문학회지
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    • 제29권spc1호
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    • pp.97-98
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    • 1996
  • Variability of active galactic nuclei is now a well-known phenomenon. This remains to be fully explained by a theoretical model of the central engine. Time scales of AGN variability seem to range continuously from hours up to months. The short time scale variability must be related to the phenomena on the event horizon of the black hole, while the long one to those in the accretion disk or surrounding matter. Based on the axisymmetric, nonstationary model of the central engine, we discuss theoretical considerations on the variability of active galactic nucleus.

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개선된 연속시간 전류모드 CMOS 적분기를 이용한 3.3V 능동 저역필터 구현 (Realization of 3.3V active low-pass filter using improved continuous-time current-mode CMOS integrator)

  • 방준호;조성익;이성룡;권오신;신홍규
    • 전자공학회논문지B
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    • 제33B권4호
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    • pp.52-62
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    • 1996
  • In this paper, a new continuous-time current-mode integrator as basic building block of the low-voltage analog current-mode active filters was proposed. Compared to the current-mode integrator which was proposed by Zele, the proposed current-mode integrator had higher unity gain frequency and output impedance in addition to lower power dissipation. And also, a current-mode third-order lowpass active filter was designed with the proposed current-mode integrator. The designed circuits were fabricated using the ORBIT's 1.2.mu.m double-poly double-metal CMOS n-well process. The experimental resutls of the active filter designed and fabricated for this research have shown that it has the performance of 44.5MHz cutoff frequency, 3.3mW power dissipation and the third-order active filter area was 0.12mm$^{2}$.

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A Semi-Markov Decision Process (SMDP) for Active State Control of A Heterogeneous Network

  • Yang, Janghoon
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제10권7호
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    • pp.3171-3191
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    • 2016
  • Due to growing demand on wireless data traffic, a large number of different types of base stations (BSs) have been installed. However, space-time dependent wireless data traffic densities can result in a significant number of idle BSs, which implies the waste of power resources. To deal with this problem, we propose an active state control algorithm based on semi-Markov decision process (SMDP) for a heterogeneous network. A MDP in discrete time domain is formulated from continuous domain with some approximation. Suboptimal on-line learning algorithm with a random policy is proposed to solve the problem. We explicitly include coverage constraint so that active cells can provide the same signal to noise ratio (SNR) coverage with a targeted outage rate. Simulation results verify that the proposed algorithm properly controls the active state depending on traffic densities without increasing the number of handovers excessively while providing average user perceived rate (UPR) in a more power efficient way than a conventional algorithm.