• Title/Summary/Keyword: Feedback-based

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Relative Effects on Construction Workers' Safety Behavior Between Global Feedback and Specific Feedback (구체적 피드백과 포괄적 피드백이 건설 현장 근로자들의 안전 행동에 미치는 상대적 효과 검증)

  • Lee, Kye-Hoon;Oah, She-Zeen
    • Journal of the Korean Society of Safety
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    • v.25 no.5
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    • pp.62-68
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    • 2010
  • The main purpose of this study was to examine relative effects on safety behaviors between global feedback and specific feedback at a construction site. Participants were 30 full-time workers at a construction site. Five safety related behaviors were identified as critical behaviors. An ABCB within-group design was adopted. After baseline (A), participants received global feedback on their average percentage of all five target safety behaviors (B). In the next phase, participants received specific feedback on the percentages of individual target behaviors (C). In the final phase, the global feedback condition was reintroduced (B). Results showed that both global feedback and specific feedback were effective in increasing the frequencies of safety behaviors and there were no differences in the effectiveness between the two types of feedbacks.

Decision Feedback Equalizer Algorithms based on Error Entropy Criterion (오차 엔트로피 기준에 근거한 결정 궤환 등화 알고리듬)

  • Kim, Nam-Yong
    • Journal of Internet Computing and Services
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    • v.12 no.4
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    • pp.27-33
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    • 2011
  • For compensation of channel distortion from multipath fading and impulsive noise, a decision feedback equalizer (DFE) algorithm based on minimization of Error entropy (MEE) is proposed. The MEE criterion has not been studied for DFE structures and impulsive noise environments either. By minimizing the error entropy with respect to equalizer weight based on decision feedback structures, the proposed decision feedback algorithm has shown to have superior capability of residual intersymbol interference cancellation in simulation environments with severe multipath and impulsive noise.

Control of Two-Link Manipulator Via Feedback Linearization and Constrained Model Based Predictive Control

  • Son, Won-Kee;Park, Jin-Young;Ryu, Hee-Seb;Kwon, Oh-Kyu
    • Transactions on Control, Automation and Systems Engineering
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    • v.2 no.4
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    • pp.221-227
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    • 2000
  • This paper combines the constrained model predictive control with the feedback linearization to solve a nonlinear system control problem with input constraints. The combined approach consists of two steps: Firstly, the nonlinear model is linearized by the feedback linearization. Secondly, based on the linearized model, the constrained model predictive controller is designed taking input constraints into consideration. The proposed controller is applied to two link robot system, and tracking performances of the controller are investigated via some simulations, where the comparisons are done for the cases of unconstrained, constrained input in feedback linearization.

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CPG-based Adaptive Walking for Humanoid Robots Combining Feedback (피드백을 결합한 CPG 기반의 적응적인 휴머노이드 로봇 보행)

  • Lee, Jaemin;Seo, Kisung
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.5
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    • pp.683-689
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    • 2014
  • The paper introduces dynamic generation technique of foot trajectories for humanoid robots using CPG(Central Pattern Generator) and proposes adaptive walking method for slope terrains combining a feedback network. The proposed CPG based technique generates the trajectory of foot in the Cartesian coordinates system and it can change the step length adaptively according to the feedback information. To cope with variable slope terrains, the sensory feedback network in the CPG are designed using the geometry relationship between foot position and body center position such that humanoid robot can maintain its stability. To demonstrate the effectiveness of the proposed approach, the experiments on humanoid robot Nao are executed in the Webot simulation. The performance and motion features of the CPG based approach are compared and analyzed focusing on the adaptability in slope terrains.

An Optical-Density-Based Feedback Feeding Method for Ammonium Concentration Control in Spirulina platensis Cultivation

  • Bao, Yilu;Wen, Shumei;Cong, Wei;Wu, Xia;Ning, Zhengxiang
    • Journal of Microbiology and Biotechnology
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    • v.22 no.7
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    • pp.967-974
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    • 2012
  • Cultivation of Spirulina platensis using ammonium salts or wastewater containing ammonium as alternative nitrogen sources is considered as a commercial way to reduce the production cost. In this research, by analyzing the relationship between biomass production and ammonium-N consumption in the fed-batch culture of Spirulina platensis using ammonium bicarbonate as a nitrogen nutrient source, an online adaptive control strategy based on optical density (OD) measurements for controlling ammonium feeding was presented. The ammonium concentration was successfully controlled between the cell growth inhibitory and limiting concentrations using this OD-based feedback feeding method. As a result, the maximum biomass concentration (2.98 g/l), productivity (0.237 g/l d), nitrogen-to-cell conversion factor (7.32 gX/gN), and contents of protein (64.1%) and chlorophyll (13.4mg/g) obtained by using the OD-based feedback feeding method were higher than those using the constant and variable feeding methods. The OD-based feedback feeding method could be recognized as an applicable way to control ammonium feeding and a benefit for Spirulina platensis cultivations.

CONTROLLER DESIGN FOR A ROBOTIC MANIPULATOR DELAYED FEEDBACK (Delayed Feedback을 이용한 로보트 제어기의 설계)

  • ;Chyung, Dong H.
    • 제어로봇시스템학회:학술대회논문집
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    • 1990.10a
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    • pp.145-148
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    • 1990
  • In this paper, the problem of designing a feedback controller for a robotic manipulator, which is activated by a D.C. motor through a gear train and a flexible shaft or chain, is considered. When the response of the closed loop control system is relatively slow, a satisfactory controller may be designed as a PID controller. As the speed of the control system increases, however, the spring effect of the linkage becomes profound, and as a result, the transient response exhibits a substantial oscillation. To eliminate this oscillation, it is necessary to design the controller based on at least a fourth order system model. This, in turn, requires the feedback of the entire state variables. In practice, however, only the position of the manipulator and the velocity of the motor are readily measurable. The state variable reconstruction method or a state observer cannot be used because of the system nonlinearities such as the Coulomb frictions. In this study, an alternative controller, which is based on delayed feedback of the output variable only, is proposed, and a successful delayed feedback controller is designed and implemented on an actual experimental manipulator.

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Complex LMS Fuzzy Adaptive Equalizer with Decision Feedback (판정궤환이 있는 복소 LMS 퍼지 적응 등화기)

  • 이상연;김재범;이기용;이충웅
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.21 no.10
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    • pp.2579-2585
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    • 1996
  • In this paper, a complex fuzzy adaptive decision feedback equalizer(CFADFE) based on the LMS algorithm is proposed. The propoed equalizer is based on the complex fuzzy adaptive equalizer. The CFADFE isconstructed from a set of changeable complex fuzzy IF-THEN rules, where the 'IF' part of the rule is characterized by the state from a set of changealble complex fuzzy IF-THEN rules, where the 'IF' part of the rule is characterized by the state of the desision feedback. the role of decision feedback is to reduce the computational complexity. Computer simulation of the decision feedback. The role of decision feedback is to reduce the computational complexity. Computer simulation shosw that the CFADFE notonly reduces the computational complexity but also improves the performance compared with the conventional complex fuzzy adaptive equalizers. We also show that the adaptation speed is greatly improved by incorporating some linguistic information about the channel into the equalzer. It is applied to M-ary QAM digital communication system with linear and nonlinear complex channel characteristics.

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Discrete-Time Output Feedback Algorithm for State Consensus of Multi-Agent Systems (다 개체 시스템의 상태 일치를 위한 이산 시간 출력 궤환 협조 제어 알고리즘)

  • Kim, Jae-Yong;Lee, Jin-Young;Kim, Jung-Su
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.3
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    • pp.625-631
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    • 2011
  • This paper presents a discrete-time output feedback consensus algorithm for Multi-Agent Systems (MAS). Under the assumption that an agent is aware of the relative state information about its neighbors, a state feedback consensus algorithm is designed based on Linear Matrix Inequality (LMI) method. In general, however, it is possible to obtain its relative output information rather than the relative state information. To reconcile this problem, an Unknown Input Observer (UIO) is employed in this paper. To this end, first it is shown that the relative state information can be estimated using the UIO and the measured relative output information. Then a certainty-equivalence type output feedback consensus algorithm is proposed by combining the LMI-based state feedback consensus algorithm with the UIO. Finally, simulation results are given to illustrate that the proposed method successfully achieves the state consensus.

The determination of state feedback gains of XPTOS for disk drive servomechanism based on BESSEL filter prototype (XPTOS에 의한 디스크 드라이브 서보메커니즘의 구성시 BESSEL 필터 표준 함수에 근거한 상태피드백이득 결정)

  • Han, K.H.;Lee, J.S.
    • Proceedings of the KIEE Conference
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    • 1996.07b
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    • pp.980-983
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    • 1996
  • This paper presents the method of determining state feedback gains of XPTOS for disk drive servomechanism based BESSEL filter prototype. A typical disk drive actuator can be modeled as second order dynamics for low frequencies. However, the response at higher frequencies shows resonant behavior which cannot be easily modeled. XPTOS consists of the nonlinear control region and the linear control region. In the linear control region, the poles of a second order nominal model of plant must be properly relocated by pole placement technique to attenuate resonant modes at high frequency and to attain minimum time state transition. It is difficult to select position to satisfy this object because velocity feedback gain is subjected to position feedback gain in XPTOS. Here poles of BESSEL filter prototype are selected to determine state feedback gains of XPTOS. Simulation results for disk drive servomechanism using XPTOS having state feedback gains by the proposed method are presented.

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Peer-revision in web-based English writing (웹기반 영작문교육에서의 동료수정 양상 연구)

  • Park, Eun-Young
    • English Language & Literature Teaching
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    • v.10 no.1
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    • pp.107-126
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    • 2004
  • This study is aimed at investigating the aspects of peer correction and responses of English composition in the web-based class. The participants for this study are students enrolled in the 'preparatory college cyber study center'. Two assignments were given--composition with no feedback and composition followed by student feedback. The participants' feedbacks, responses, and attitudes in peer interaction were analysed. The processes of these two assignments were also compared. The results were as follows: First, students' competitive attitude changed into cooperative attitude when peer-revision was followed. Second, both formal and content feedback were shown in the cyber composition class just as in the classroom composition class, but under no specific guidance, the majority of students' feedbacks were formal feedbacks. Third, some characteristics of web-based writing were found. In the web-based writing class where around a hundred students are enrolled. students' feedbacks were inevitable. The results of this study supported the use of students feedback.

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