• Journal of Drive and Control
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• 제18권4호
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• pp.77-83
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• 2021

With the progress in virtual reality technology, various virtual objects can be displayed using head-mounted displays (HMD). However, force feedback sensations such as pushing against a virtual object are not possible with an HMD only. Focusing on force feedback, desktop-type devices are generally used, but the user cannot move in a virtual space because such devices are fixed on a desk. With a wearable force feedback device, users can move around while experiencing force feedback. Therefore, the authors have developed a wearable force feedback device using a magnetorheological fluid clutch and pneumatic rubber artificial muscle, aiming at presenting the elasticity, friction, and viscosity of an object. To date, we have developed a wearable four-degree-of-freedom (4-DOF) force feedback device and have quantitatively evaluated that it can present commanded elastic, frictional, and viscous forces to the end effector. However, sensory evaluation with a human has not been performed. In this paper, therefore, we conduct a sensory evaluation of the proposed method. In the experiment, frictional and viscous forces are rendered in a virtual space using a 4-DOF force feedback device. Subjects are asked to answer questions on a 1- to 7-point scale, from 1 (not at all) to 4 (neither) to 7 (strongly). The Wilcoxon signed rank test was used for all data, and answer 4 (neither) was used as compared standard data. The experimental results confirmed that the user could feel the presence or absence of viscous and frictional forces. However, the magnitude of those forces was not sensed correctly.

• Journal of the Korea Safety Management & Science
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• 제12권4호
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• pp.265-272
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• 2010

This study examined the relative effects of weekly and daily group feedback on the customer service behaviors in a gas station. Participants were four employees providing full services to the customers. Four target service behaviors, which were identified from the job description for the employees, served as the dependent variables. The data were collected by a supervisor. The independent variable was the frequency of group feedback on the four service behaviors: weekly and daily group feedback. An ABC within group design was adopted. After baseline (A), the weekly group feedback condition (B) was introduced. In the next phase, the daily group feedback condition (C) was introduced. Both weekly and daily group feedback were presented in a graph form and posted at a conspicuous location. Results showed that both weekly feedback and daily feedback conditions were effective in increasing the target behaviors. And, there was difference in the effects between the two conditions.

• Journal of the Korea Safety Management & Science
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• 제7권5호
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• pp.213-231
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• 2005

Assignable causes producing temporary deviation from the underlying system can influence on process adjustment and process monitoring in dynamic feedback control system. In this paper, the influence of assignable causes on EWMA forecasts and compensatory variables are derived for a dynamic feedback control system. An example is presented to confirm the impact numerically through the analysis of a data.

• KIPS Transactions on Software and Data Engineering
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• 제6권2호
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• pp.91-102
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• 2017

Many of the wearable smart fitness devices provide services related to users' heartbeat rates. These services use fixed standards which have been pre-determined based on statistical data. However, because body conditions significantly differ between individuals, the services applying fixed standards to all individuals are not reliable. This paper proposes the Feedback-RFC model which adapts heartbeat standards to individual users' exercise abilities and also proposes a method to implement the model. This paper also shows the effectiveness of the Feedback-RFC model by collecting heartbeat data from 12 participants and evaluating the model with the data.

• Journal of Electrical Engineering and information Science
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• 제3권1호
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• pp.126-130
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• 1998

In this paper, a new interference rejection filter using the data-recycling technique is presented. The reference signal of the interference rejection filter is formed by using chip decisions, which is correlated with the narrowband interference components of the received signal. The decision feedback techniques reduce the distortion of the desired signal, which is introduced by the interference rejection filter through he use of feedback chip decisions. In order to update the filter coefficients a simple and efficient data-recycling technique that has improved performance over the conventional LMS algorithm is used. The performance of the proposed interference rejection filter is compared to filter with conventional LMS linear filter. The results show that the convergence speed of the proposed interference rejection filter using decision feedback and data-recycling technique is significantly faster than that of the conventional filters. Also, BER performance of the interference rejection filter demonstrates the superiority of the proposed filter algorithm.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제16권5호
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• pp.3220-3229
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• 2015

This study analyzed the effect of team feedback environment on feedback-seeking behavior, and further explored how feedback-seeking behavior led to the feeling of thriving at work and team commitment. Also, we examined the moderating effect of self-efficacy on the relationship between team feedback environment and feedback-seeking behavior. Using survey data from 201 workers employed in various industries in Korea, we found that team feedback environment was positively related to feedback-seeking behavior, and that the relationship was moderated by self-efficacy. In addition, feedback-seeking behavior was positively associated with the feeling of thriving at work and team commitment. The result suggests the importance of feedback-seeking behavior in improving performance as well as work attitude and energy. The result also emphasizes the critical role that team feedback environment plays, and the need to find ways to nurture the environment that fosters feedback seeking and giving.

• The Journal of Korean Academic Society of Nursing Education
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• 제25권2호
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• pp.186-196
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• 2019

Purpose: This study was conducted to identify types of peer feedback in nursing skills performance training and to investigate emotional response, perceived quality of feedback and self-efficacy for learning from peer feedback. Methods: A total of 110 second-year nursing students attending fundamentals of nursing classes at a university participated in 2017. Participants received peer feedback from one selected colleague who observed their skills performance, and completed a questionnaire. Contents of peer feedback video recordings were transcribed and classified into seven types of feedback. Data were analyzed using an independent t-test, ANOVA and Pearson correlation. Results: Participants mostly received feedback of 'correcting' and 'providing information.' Positive emotional responses from peer feedback were above medium, and negative emotional responses were low. The perceived quality of peer feedback was moderate and self-efficacy for learning was high. Quality of feedback correlated with negative emotional response (r=-.24, p=.014), and self-efficacy for learning (r=.35, p<.001). Self-efficacy for learning correlated with intimacy with peers (r=.24, p=.011) and positive emotional response (r=.21, p=.028). Conclusion: The results suggest that peer feedback in skill training could be used in terms of emotional response and self-efficacy for learning.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 한국공작기계학회 2004년도 춘계학술대회 논문집
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• pp.235-240
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• 2004

The equipment of industrial robot in manufacturing and assembly lines has rapidly increased. In order to achieve high productivity and flexibility, it becomes very important to develop the visual feedback control system with Off-Line Programming System(OLPS). We can save much efforts and time in adjusting robots to newly defined workcells by using OLPS. A proposed visual calibration scheme is based on position-based visual feedback. The calibration program firstly generates predicted images of objects in an assumed end-effector position. The process to generate predicted images consists of projection to screen-coordinates, visible range test and construction of simple silhouette figures. Then camera images acquired are compared with predicted ones for updating position and orientation data. Computation of error is very simple because the scheme is based on perspective projection which can be also expanded to experimental results. Computation time can be extremely reduced because the proposed method does not require the precise calculation of tree-dimensional object data and image Jacobian.

• Journal of the Korea Convergence Society
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• 제10권12호
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• pp.503-510
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• 2019

This study aimed to analyze the effects of nursing students' learning motivation, learning attitude and academic self-efficacy on their application of reflective journal with teaching feedback. For this retrospective comparative study data from 190 undergraduate students in the health assessment skills course from 2018 to 2019. The collected data were analyzed by chi-square test, independent t-test, Ancova. After writing reflection journal with teaching feedback showed significant difference in learning motivation(t=2.10, p=.037) and learning attitude (t= 4.54, p=.034) compared to writing reflection journal without teaching feedback. However, no significant difference was found between reflection journal with teaching feedback and reflection journal without teaching feedback. These results suggest writing reflection with teaching feedback is an effective strategy for improving learning motivation and learning attitude.

• Korean Journal of Applied Biomechanics
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• 제30권3호
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• pp.247-253
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• 2020

Objective: This study aimed to examine the effects of real-time visual feedback gait training on gait stability in older adults. Method: Twelve older adults participated in this study, being divided into 2 groups including a) visual feedback (VF) and b) non-visual feedback (NVF) groups. For 4 weeks, VF performed a treadmill walking training with real-time visual feedback about their postural information while NVF performed a normal treadmill walking training. For evaluations of gait stability, kinematic data of 15-minute treadmill walking were collected from depth-based motion capture system (30 Hz, exbody, Korea). Given that step lengths in both right and left sides were determined based on kinematic data, three variables including step difference, coefficient of variation, approximate entropy were calculated to evaluate gait symmetry, variability and complexity, respectively. Results: For research findings, VF exhibited significant improvements in gait stability after 4-week training in comparison to NVF, particularly in gait symmetry and complexity measures. However, greater improvement in gait variability was observed in NVF than VF. Conclusion: Given that visual feedback walking gives potential effectiveness on gait stability in older adults, gait training with visual feedback may be a robust therapeutic intervention in people with gait disturbances like instability or falls.