• 한국안전학회지
• /
• 제25권5호
• /
• pp.62-68
• /
• 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.

• 한국안전학회지
• /
• 제30권6호
• /
• pp.132-138
• /
• 2015

This study examined the relative effects of feedback frequency and specificity of Eco-IVIS(eco in-vehicle information system) on the fuel-efficiency and workload. Eighty participants randomly assigned into four experimental groups (high frequency/specific, high frequency/global, low frequency/specific, and low frequency/global feedback) and they drove 16.4Km motorway under the each feedback condition. The dependent variable were fuel efficiency and Drive Activity Load Index which measured participants' subjective ratings of driving workload. The results showed that high frequent feedback was more effective for increasing fuel-efficiency than low frequent feedback, however, there was no significant difference of fuel-efficiency between specific and global feedback. Although, overall DALI score was comparable among four experimental conditions, visual demand score was significant higher under the high frequent feedback condition than low frequent feedback.

• Transactions on Control, Automation and Systems Engineering
• /
• 제2권2호
• /
• pp.104-109
• /
• 2000

In this paper, the output feedback stabilizing problem is solved using any given state feedback control law. Compared to the linear systems is not so straightforward for nonlinear systems. We briefly explain the intrinsic obstructions for this problem and provide new output feedback scheme which achieves the semi-global stabilization with the high-gain state observer. THe overall uniform observability of the plant. Therefore, the result can be regarded as an extension of the separation principle for linear systems in some aspect.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
• /
• pp.272-275
• /
• 1989

In this paper feedback linearization of valve-controlled nonlinear hydraulic velocity control system is studied. The $C^{\infty}$ nonlinear transformation T is obtained, and it is shown that this transformation is global one. Linear equivalence of nonlinear hydraulic velocity control system is obtained by this global nonlinear transformation, and linear state feedback control law is applied to this linear model. It is shown that this transformation method is to the linear approximation by simulation study..

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2005년도 ICCAS
• /
• pp.557-560
• /
• 2005

This paper considers a global asymptotic output tracking problem with a prescribed constant reference signal for a class of single-input and single output-output nonlinear systems. It is shown that under some mild conditions on such a system there is a smooth output feedback achieving global asymptotic output tracking and such a smooth output controller is explicitly constructed by a new design method proposed. The usefulness of our result is illustrated by a numerical example.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제7권4호
• /
• pp.692-710
• /
• 2013

Conventional interference alignment (IA) for a MIMO interference channel (IFC) requires global and perfect channel state information at transmitter (CSIT) to achieve the optimal degrees of freedom (DoF), which prohibits practical implementation. In order to alleviate the global CSIT requirement caused by the coupled relation among all of IA equations, we propose an IA scheme with a single feedback link of each receiver in a limited feedback environment for a three-user MIMO IFC. The main feature of the proposed scheme is that one of users takes out a fraction of its maximum number of data streams to decouple IA equations for three-user MIMO IFC, which results in a single link feedback structure at each receiver. While for the conventional IA each receiver has to feed back to all transmitters for transmitting the maximum number of data streams. With the assumption of a random codebook, we analyze the upper bound of the average throughput loss caused by quantized channel knowledge as a function of feedback bits. Analytic results show that the proposed scheme outperforms the conventional IA scheme in term of the feedback overhead and the sum rate as well.

• Journal of Advanced Marine Engineering and Technology
• /
• 제38권8호
• /
• pp.1000-1003
• /
• 2014

There are 70 vertical and 70 horizontal correctors for Pohang Light Source. Until mid of 2000, power supplies for these correctors were based on 1990's technology, so the global orbit feedback system was not possible with poor 12 bit resolution. A new task force team was assembled to develop new power supplies with BESSY type DAC cards. After the project, two vertical correctors in each lattice were connected with new power supplies, and the global orbit feedback was available within the accuracy of 5 microns. However, this replacement was not enough to satisfy the beam stability requirement of 2 microns for PLS. We have launched another power supply design based on all digital technology. This attempt was completed within a year, and 80 units were assembled in house. Currently, the global orbit feedback system is running successfully with new digital power supplies and the compensation of chamber motion due to the thermal load by using digital displacement transducers attached on each BPMs.

• 대한임베디드공학회논문지
• /
• 제10권6호
• /
• pp.373-379
• /
• 2015

A hybrid navigation system is implemented to apply for a mobile robot. The hybrid navigation system consists of an inertial navigation system and a global positioning system. The inertial navigation system quickly calculates the position and the attitude of the robot by integrating directional accelerations, angular speed, and heading angle from a strap-down inertial measurement unit, but the results are available for a short time since it tends to diverge quickly. Global positioning system delivers position, heading angle, and traveling speed stably, but it has large deviation with slow update. Therefore, a hybrid navigation system uses the result from an inertial navigation system and corrects the result with the help of the global positioning system where an indirect feedback Kalman filter is used. We implement and confirm the performance of the hybrid navigation system through driving a car attaching it.

• 대한물리의학회지
• /
• 제7권3호
• /
• pp.309-318
• /
• 2012

Purpose : The purpose of this study was to compare 2 different interventions, global postural re-education (GPR) and specific spinal stabilization exercise in the healthy elderly of women. Methods : A total of 28 subjects were randomized into 2 treatment groups: GPR, where therapy involved muscle global chain stretching, or specific spinal stabilization exercise with conventional static stretching (GPR group: n=14, specific spinal stabilization exercise group: n=14). Both groups received exercise intervention 3 times a week for 12-weeks. Results : Outcome was based on trunk endurance, trunk flexibility, Pressure Bio Feedback, Oswestry Disability Index measured immediately before and after intervention. Trunk flexibility, Pressure Bio Feedback, Oswestry Disability Index improved more in GPR group after intervention. There were no differences between the 2 exercise approaches for any of the trunk endurance. Conclusion : As the above results, GPR appear to improve Trunk flexibility, Pressure Bio Feedback, Oswestry Disability Index to the elderly of women. The efficacy of the GPR program used in this study should be further investigated in a long period study and objective outcomes.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1996년도 하계학술대회 논문집 B
• /
• pp.1137-1139
• /
• 1996

Feedback Linearization technique needs the exact cancellation of nonlinearity which restricts its application to real environment. To overcome these shortcomings, High-pin feedback is good remedy to this problem. In this paper, we briefly survey the high-gain feedback control technique and show some conditions for applying this method to nonlinear systems. In order to use this technique in real situation, some properties of ${\varepsilon}$-bound and semi-global stabilization are discussed.