• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.1981-1986
• /
• 2004

In this study, the basic motor control system had been investigated. The controller for this study consists of two main parts, a feedforward controller part and a feedback controller part. Each part will deals with different control problems. The feedback controller deals with robustness and stability, while the feedforward controller deals with response speed. The feedforward controller, used to solve the tracking control problem, is adaptable. To make such a tracking perfect, an adaptive law based on Feedback Error Learning (FEL) is designed so that the feedforward controller becomes an inverse system of the controlled plant. The novelty of FEL method lies in its use of feedback error as a teaching signal for learning the inverse model. The theory in $H^{\infty}$-Control is selected to be applied in the feedback part to guarantee the stability and solve the robust stabilization problems. The simulation of each individual part and the integrated one are taken to clarify the study.

• Proceedings of the KIEE Conference
• /
• 2001.07d
• /
• pp.2249-2251
• /
• 2001

This paper proposes that it minimizes interference between link at high speed trajectory tracking of 2-degree parallel link manipulator and QFT(Quantitative Feedback Theory) controller which robust structure uncertainty and disturbance of plant. And using ICD(Individual Channel Design), it separates two channel from multivariable system, parallel link manipulator and designs robust controller with applying MISO QFT to each channel. Finally, we make sure of robustness and excellence of QFT controller through simulation and experiment.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.1911-1916
• /
• 2005

In this study, the basic motor control system had been investigated. The Discrete-Time Feedback Error Learning (DTFEL) method is used to control this system. This method is anologous to the original continuous-time version Feedback Error Learning(FEL) control which is proposed as a control model of cerebellum in the field of computational neuroscience. The DTFEL controller consists of two main parts, a feedforward controller part and a feedback controller part. Each part will deals with different control problems. The feedback controller deals with robustness and stability, while the feedforward controller deals with response speed. The feedforward controller, used to solve the tracking control problem, is adaptable. To make such the tracking perfect, the adaptive law is designed so that the feedforward controller becomes an inverse system of the controlled plant. The novelty of FEL method lies in its use of feedback error as a teaching signal for learning the inverse model. The PD control theory is selected to be applied in the feedback part to guarantee the stability and solve the robust stabilization problems. The simulation of each individual part and the integrated one are taken to clarify the study.

• The Journal of Information Systems
• /
• v.23 no.2
• /
• pp.91-107
• /
• 2014

In computer-mediated idea generation where contributions can be anonymous, the ability to accurately monitor performances is limited, inducing social loafing. Prior research has suggested that social loafing is likely an important factor in reducing task performance. Researchers have theorized that loafing could be minimized if clear performance feedback is provided. Our prior study evidences a substantial performance gain by the provision of real time performance information about who is contributing and who is not. However, our prior study incorporated the quantity feedback only to create a larger pool of ideas based on the long-standing assumption (i.e., quantity breeds quality), not considering the quality feedback. As a result, taking advantage of anonymity in the form of pseudonymity, individuals in almost all groups exhibited a tendency of self-presentation by capitalizing on ideas of which quality was low and even frivolous (i.e., junk comments) toward the later stages of the session. Thus, we have learned that the quantity performance feedback alone does not have enough restrictiveness to consistently control the performance behavior throughout the session. Since a process chart allows participants to monitor process variation by comparing new performance data to past performance data, we incorporated real-time visual process performance feedback to reveal performance histories by connecting the sequence of idea quality scores in a time-series format. Using this environment, a laboratory experiment was conducted with five-member groups that examined the influence of both identifiability (i.e., anonymity versus pseudonymity) and process performance feedback (i.e., yes or no) in a $2{\times}2$ factorial design. The result showed that groups in the process performance feedback treatment outperformed groups in the no feedback treatment. Additionally, process performance feedback and identifiability interacted such that groups in the process performance feedback/pseudonymity treatment had the highest performance. The implications of these findings for future research, as well as the implications for the design of group idea generation procedures are discussed.

• Research in Mathematical Education
• /
• v.19 no.1
• /
• pp.43-59
• /
• 2015

In the present study, the changes of mathematics teachers' verbal feedback between ten years ago and later were examined using a coding scheme on the types of teacher verbal feedback. Based on the analysis, it is found that teachers intend to use encouraging strategies to make responses to students ten years later. In addition, the duration used in communication between the teacher and individual student is being longer while the frequency of communication becomes less compared ten years ago. Meanwhile, the difference between good lesson ten years ago and common lesson ten years later is not so apparent. It can be inferred that the quality of teaching has being developed.

• ETRI Journal
• /
• v.33 no.2
• /
• pp.240-250
• /
• 2011

To enable a relevance feedback paradigm to evolve itself by users' feedback, a reinforcement learning method is proposed. The feature space of the medical images is partitioned into positive and negative hypercubes by the system. Each hypercube constitutes an individual in a genetic algorithm infrastructure. The rules take recombination and mutation operators to make new rules for better exploring the feature space. The effectiveness of the rules is checked by a scoring method by which the ineffective rules will be omitted gradually and the effective ones survive. Our experiments on a set of 10,004 images from the IRMA database show that the proposed approach can better describe the semantic content of images for image retrieval with respect to other existing approaches in the literature.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.1C
• /
• pp.9-13
• /
• 2003

We consider a two-phase queueing system with Bernoulli feedback. Customers arrive at the system according to a Poison process and receive batch service in the first phase followed by individual services in the second phase. Each customer who completes the individual service returns to the tail of the second phase service queue with probability 1 -$\sigma$. This type of queueing problem cad be easily found in computer and telecommunication systems. By deriving a relationship between the generating functions for system size at various embedded epochs, we obtain the system size distribution. The exhaustive and gated cases for the batch service are considered.

• Proceedings of the KIEE Conference
• /
• 2004.05a
• /
• pp.13-15
• /
• 2004

In this paper, we propose a novel stability criterion and a guideline of controller design for switched linear systems. Unlike existing criterions such as Lie algebraic method and multiple Lyapunov functions method, the proposed criterion can be applied to each individual system without considering an overall system. By applying the proposed criterion to each individual system separately, a state feedback controller can be easily designed. Stability of the overall system is proved by developing a rule to determine non-increasing Lyapunov functions recursively at each switching instant. An illustrative example is given.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2000.10a
• /
• pp.77-80
• /
• 2000

Feedback herding strategy in stock market means considering other investor's strategy as a basis of market forecasting of next term. Generally, individual investors use that strategy which mimics the strategy of institutional investors. When it is used in stock market, both kind of investors, preceders and followers, can take the higher average of rate of return to normal market in which no feedback herding strategy is not use, the more investors take part in. And variance of return, the risk of investment, are same to both group.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2008.10a
• /
• pp.692-695
• /
• 2008

Large area emissive displays have problems with nonuniform pixel characteristics and their individual ageing. A pixel integrated driver with pixel based optical feedback is presented to solve these problems. Photodetectors, optical feedback circuit and data handling capabilities are integrated in a high voltage CMOS technology.