• Title/Summary/Keyword: Dual-Function

Search Result 706, Processing Time 0.029 seconds

Periodic Disturbance Cancellation by using Dual-Input Describing Function (DIDF) Method (DIDF 방법을 이용한 주기성 외란의 제거)

  • Choe, Yeon-Wook;Lee, Hyung-Ki
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.59 no.1
    • /
    • pp.168-175
    • /
    • 2010
  • The issue of rejecting periodic disturbances arises in various applications dealing with rotating machinery. A new method using DIDF (Dual-Input Describing Function) is presented for the rejection of periodic disturbances with uncertain frequency. This can be added to an existing feedback control system without altering the closed-loop system stability. The objective is to design a nonlinear compensator to secure specified oscillation amplitude and frequency which are the same as disturbances. We suggest two procedures to determine coefficients for DIDF's synthesis. The structure of the proposed DIDF is so simple that we can easily synthesize. A number of computer simulations were carried out to demonstrate the salient feature of the proposed DIDF compared to the conventional ones(that is, adaptive algorithms).

NEW INTERIOR POINT METHODS FOR SOLVING $P_*(\kappa)$ LINEAR COMPLEMENTARITY PROBLEMS

  • Cho, You-Young;Cho, Gyeong-Mi
    • Journal of the Korean Society for Industrial and Applied Mathematics
    • /
    • v.13 no.3
    • /
    • pp.189-202
    • /
    • 2009
  • In this paper we propose new primal-dual interior point algorithms for $P_*(\kappa)$ linear complementarity problems based on a new class of kernel functions which contains the kernel function in [8] as a special case. We show that the iteration bounds are $O((1+2\kappa)n^{\frac{9}{14}}\;log\;\frac{n{\mu}^0}{\epsilon}$) for large-update and $O((1+2\kappa)\sqrt{n}log\frac{n{\mu}^0}{\epsilon}$) for small-update methods, respectively. This iteration complexity for large-update methods improves the iteration complexity with a factor $n^{\frac{5}{14}}$ when compared with the method based on the classical logarithmic kernel function. For small-update, the iteration complexity is the best known bound for such methods.

  • PDF

Dual-Hop Amplify-and-Forward Multi-Relay Maximum Ratio Transmission

  • Erdogan, Eylem;Gucluoglu, Tansal
    • Journal of Communications and Networks
    • /
    • v.18 no.1
    • /
    • pp.19-26
    • /
    • 2016
  • In this paper, the performance of dual-hop multi-relay maximum ratio transmission (MRT) over Rayleigh flat fading channels is studied with both conventional (all relays participate the transmission) and opportunistic (best relay is selected to maximize the received signal-to-noise ratio (SNR)) relaying. Performance analysis starts with the derivation of the probability density function, cumulative distribution function and moment generating function of the SNR. Then, both approximate and asymptotic expressions of symbol error rate (SER) and outage probability are derived for arbitrary numbers of antennas and relays. With the help of asymptotic SER and outage probability, diversity and array gains are obtained. In addition, impact of imperfect channel estimations is investigated and optimum power allocation factors for source and relay are calculated. Our analytical findings are validated by numerical examples which indicate that multi-relay MRT can be a low complexity and reliable option in cooperative networks.

Development of Dual-task Based Cognitive Function Screening Test for the Elderly (이중과제를 활용한 노인인지기능 선별검사 개발)

  • Kwak, Ho-Soung;Yoo, Eun-Young;Park, Hae Yean;Lee, Seo-Hyun;Han, Dae-Sung;Park, Ji-Hyuk
    • Therapeutic Science for Rehabilitation
    • /
    • v.9 no.4
    • /
    • pp.69-81
    • /
    • 2020
  • Objective : The purpose of this study was to develop a Yonsei dual task cognitive screening test (Y-DuCog) for the elderly. Methods : The reliability and validity test of Y-DuCog (Yonsei Dual Task Cognitive Screening Test) was developed by 229 elderly people aged over 60 years from community organizations at Gyeonggi-do and Chungcheong-do from May 2019 to August 2019. In addition, the criteria for classifying elderly with cognitive impairment were presented. Results : The correlation analysis between MMSE-K, MoCA-K and Y-DuCog were a correlation between the DTE and CRR of Y-DuCog. As a result of internal consistency, Cronbach's-α values of DTE and CRR showed .848 (p<.01) and .916 (p<.01), respectively. The test-retest reliability was high. The screening point showed 88.7% sensitivity and 83.5% specificity at 31.76 seconds in total DTE, and 84.5% sensitivity and 76.6% specificity at 0.38 in total dual-task CRR. Conclusion : This study verified the reliability and validity of Y-DuCog. It was found that the level of education was not a barrier to the undertaking of this test. Furthermore, the test could be performed easily and quickly. It is also expected to be used to evaluate the effectiveness of cognitive function assessment and intervention methods in the elderly.

Stepping Trail Making Test: Preliminary Study for the Effectiveness of the Novel Dual Task Assessment Tool for Physical and Cognitive Functions in Elderly (보행기호잇기검사: 새로운 신체 및 인지 기능에 대한 이중 과제 평가도구로서의 효용성에 대한 예비연구)

  • Ju-Ri Eom;Byeong-Ju Lee
    • Journal of the Korean Society of Physical Medicine
    • /
    • v.18 no.2
    • /
    • pp.41-48
    • /
    • 2023
  • PURPOSE: Falls are caused by a decline in physical and cognitive function. A quantitative evaluation tool that can comprehensively evaluate motor and cognitive functions for elderly people with an impaired physical function. This study assessed the clinical application potential by confirming the correlation between the physical function tests, cognitive and the stepping trail-making test (S-TMT). METHODS: Fourteen community-dwelling older patients (65-75 years) were recruited. The study conducted cognitive function tests with the trail-making test (TMT-A, B), and physical function tests (6-minute walking test (6MWT), short physical performance battery (SPPB), and timed up and go (TUG)). The results of were analyzed using SPSS version 21.0. Descriptive statistics were used for the general characteristics of the study subjects, and the correlations between S-TMT, other functional tests were examined through Pearson's correlation analysis. The statistical significance was set to .05. RESULTS: S-TMT had a significant positive correlation with the TUG (r = .588*) and trail-making test-B (TMT-B) (r = .689*, p < .05). Furthermore, S-TMT showed a negative correlation between SPPB (r = -.397) and 6MWT (r = -.422), but it was not statistically significant. CONCLUSION: S-TMT is a cognitive-gait dual-task performance evaluation tool that can be performed safely. A significant correlation was confirmed between the TUG test and the TMT-B. S-TMT is a dual-task screening tool that can evaluate both physical and cognitive functions simultaneously.

The Performance of Dual Structure CR-CMA Adaptive Equalizer for 16-QAM Signal (16-QAM 신호에 대한 이중 구조 CR-CMA 적응 등화기의 성능)

  • Yoon, Jae-Sun;Lim, Seung-Gag
    • The Journal of the Institute of Internet, Broadcasting and Communication
    • /
    • v.12 no.5
    • /
    • pp.107-114
    • /
    • 2012
  • In this paper, the concerned existing blind equalizer convergence rate and residual inter-symbol interference using constellation reduced and cost function by separation the real part and an imaginary part, the dual structure CR-CMA(constellation Reduction CMA). The CMA methed compensates amplitude but does no compensate phase, On the other hand, The CMA method compensates both the amplitude and the phase but it has the convergence rate problem, and the MCMA method is a way to solve the phase problem of CMA method compensates both the amplitude and the phase after respectively calculating the real part and imaginary part components. Proposal a new method that the dual structure of CR-CMA, the cost function and error function and respectively calculating the real part and imaginary part components can advantages by improving the CMA and the MCMA algorithms so that the amplitude and phase retrieval and constellation reduce the residual ISI and faster convergence rate and performance is good SER (Symbol Error Ratio) was confirmed by computer simulations.

Sliding Wear Mechanism of Ultra-Fine Grained Low Carbon Dual Phase Steel as n Function of Applied Load (결정립 미세화에 따른 이상조직 탄소강의 하중에 따른 마멸 기구)

  • Yu, H.S.;Yi, S.K.;Shin, D.H.;Kim, Y.S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • 2007.05a
    • /
    • pp.421-424
    • /
    • 2007
  • Dry sliding wear behavior of ultra-fine grained (UFG) plain low carbon dual phase steel, of which microstructure consists of hard martensite in a ductile ferrite matrix, has been investigated. The wear characteristics of the UFG dual phase steel was compared with that of a coarse grained dual phase steel under various applied load conditions. Dry sliding wear test were carried out using a pin-on-disk type tester at various loads of 1N to 100N under a constant sliding speed condition of 0.20m/s against an AISI 52100 bearing steel ball at room temperature. The sliding distance was fixed as 1000m for all wear tests. The wear rate was calculated by dividing the weight loss, measured to the accuracy of 10-5g by the specific gravity and sliding distance. The worn surfaces and wear debris were analyzed by SEM, EDS and profilometer. Micro-vickers hardness of the cross section of worn surfaces were conducted to analyze strain hardening underneath the contact surfaces. The wear mechanism of the UFG dual phase steel was investigated with emphasis on the unstable nature of the grain boundaries of the UFG microstructure.

  • PDF

Evaluation of Performance Index of Dual-arm manipulator for Multiple Shape Object Handling (Multiple Shape Object Handling을 위한 양팔로봇의 성능지수 평가)

  • Son, Joon-Bae;Chen, Hu;Lee, Jang-Myung
    • The Journal of Korea Robotics Society
    • /
    • v.7 no.1
    • /
    • pp.9-19
    • /
    • 2012
  • This paper proposes a performance index for the multiple shape object handling of dual arm manipulator to determine whether a robot is good or not. When the dual-arm manipulator grasps a fixed object and is posed, the dual-arm manipulator should procure a space to freely control the manipulator. As a performance evaluation parameter, each joint torque from current sensor signal is utilized. From the current information, torque and energy for each joint are estimated. In this paper an performance index for an unstructured object is defined by an energy-cost function, and stability analysis for each motion is derived by the maximum force to the object. The maximum force to the object is computed by the inertia of object and acceleration information of end-effector. The acceleration data are derived by the double derivation of each encoder signal. Manipulability measure which implies how efficiently the dual-arm manipulator can move with the grasped object, can be represented by the intersection of the two manipulability ellipsoids for the left and right arms. Effectiveness of the proposed algorithm has been verified through the practical simulations and real experiments.

Sliding Wear Mechanism of Ultra-Fine Grained Low Carbon Dual Phase Steel as a Function of Applied Load (경정립 미세화에 따른 이상조직 탄소강의 하중에 따른 마멸기구)

  • Yu, H.S.;Yi, S.K.;Shin, D.H.;Kim, Y.S.
    • Transactions of Materials Processing
    • /
    • v.16 no.4 s.94
    • /
    • pp.299-303
    • /
    • 2007
  • Dry sliding wear behavior of ultra-fine grained(UFG) plain low carbon dual phase steel, of which microstructure consists of hard martensite in a ductile ferrite matrix, has been investigated. The wear characteristics of the UFG dual phase steel was compared with that of a coarse grained dual phase steel under various applied load conditions. Dry sliding wear test were carried out using a pin-on-disk type tester at various loads of 1N to 100N under a constant sliding speed condition of 0.20m/s against an AISI 52100 bearing steel ball at room temperature. The sliding distance was fixed as 1000m for all wear tests. The wear rate was calculated by dividing the weight loss, measured to the accuracy of 10-5g by the specific gravity and sliding distance. The worn surfaces and wear debris were analyzed by SEM, EDS and profilometer. Micro-vickers hardness of the cross section of worn surfaces were conducted to analyze strain hardening underneath the contact surfaces. The wear mechanism of the UFG dual phase steel was investigated with emphasis on the unstable nature of the grain boundaries of the UFG microstructure.

Design and Realization. of the Dual-mode Channel Filter and Group-Delay-and-Amplitude Equalizer for the Ka-band Satellite Transponder Subsystem

  • Sungtek Kahng;Uhm, Man-Seok;Lee, Seong-Pal
    • Journal of electromagnetic engineering and science
    • /
    • v.3 no.2
    • /
    • pp.140-146
    • /
    • 2003
  • In this paper, the design of a channel filter and its group-delay-and-amplitude equalizer is carried out for the Ka-band satellite transponder subsystem. The 8th order dual-mode filter is employed for high selectivity around the band-edges with an elliptic-integral function response and has an in-line configuration. The 2-pole, reflection-type, group-delay equalizer is designed and manufactured to reduce the group-delay and amplitude variation, which can be large for such a high order filter. It is noted that in both the filter and equalizer, adopting the dual-mode coupling mechanism leads to less mass and volume. Through measurement, the performance of the realized group-delay-equalized filter is shown to meet the equipment requirements and to be appropriate for the satellite input multiplexer.