• The Journal of Korea Robotics Society
• /
• v.17 no.3
• /
• pp.282-287
• /
• 2022

High shear adhesion on wet and rough surfaces and tactile feedback of gripping forces are highly important for realizing robotic gripper systems. Here, we propose a bioinspired robotic gripper with highly shear adhesion and sensitive pressure sensor for tactile feedback systems. To achieve them, we fabricated multi-walled carbon nanotube sensing layer on a thin polymeric adhesive layer of polydimethylsiloxane. With densely hexagonal-packed microstructures, the pressure sensor achieved 9 times the sensing property of a sensor without microstructures. We then assembled hexagonal microstructures inspired by the toe pads of a tree frog, giving strong shear adhesion under both dry and wet surfaces such as silicon (42 kPa for dry and ~30 kPa for underwater conditions) without chemical-residues after detachment. Our robotic gripper can prevent damage to weak or smooth surfaces that can be damaged at low pressure through pressure signal feedback suggesting a variety of robotic applications.

• Information Systems Review
• /
• v.16 no.1
• /
• pp.1-15
• /
• 2014

Despite the sizable growth of the group buying market, consumer complaints have recently raised skepticism about the future of these sites. Thus, building a trustworthy transaction environment has become a critical issue. In exploring a trust-building mechanism, we pay particular attention to the role of merchandisers who specialize in finding products or services and marketing them to potential buyers on group buying sites. The purpose of this study is to examine whether providing merchandiser feedback comments and performance profiles on group buying sites leads consumers to evaluate the community of merchandisers more favorably and makes them more likely to purchase products or services. Research hypotheses were tested with data obtained from 124 subjects who participated in a laboratory experiment. The results empirically demonstrate that merchandiser feedback comments and performance profiles enhance buyers' trust in the community of merchandisers participating in a group buying site. This enhanced trust, in turn, increased buyers' intention to purchase products or services through the group buying site.

• The Journal of the Korea Contents Association
• /
• v.16 no.9
• /
• pp.117-126
• /
• 2016

This study examined the relative effects of different feedback delivery method (face-to-face vs. e-mail) and reinforcement history on work performance. Participants were asked to work on a simulated mobile phone assembly task. They performed for 30 minutes per session and attended 4 sessions. The dependents variable was the percentage of correctly completed work tasks. Of 100 participants recruited, 50 had a reinforcement history and another 50 had no reinforcement history with the feedback provider in this study. The participants in each group were randomly assigned into two experimental conditions: face-to-face feedback and e-mail feedback. The results showed that for the participants who had reinforcement history, the two feedback delivery methods did not produce a significant difference in the percentage of correctly completed work tasks. However, for those who had no reinforcement history, the two feedback methods did produce a significant difference.

• The Journal of Information Systems
• /
• v.26 no.4
• /
• pp.1-15
• /
• 2017

Purpose Through the provision of real time performance information about who is contributing and who is not in Electronic Brainstorming, prior studies evidenced a significant performance gain. However, it has been observed that the quantity-based performance feedback alone does not have enough restrictiveness to guide the performance behavior throughout the idea generation session. We included the notion of goal setting into the process performance feedback mechanism in an effort to regulate performance behavior and to better understand why individuals in Electronic Brainstorming are not obtaining enough stimulation benefits in the group interaction process. Design/methodology/approach We had developed real-time visual process performance feedback and modified to include goal setting. This mechanism visually displays individuals' performances two-dimensionally (quality for each idea vertically and quantity of ideas horizontally along with their goals). As individuals' contributions accumulate, the mechanism reveals performance histories by connecting the sequence of ideas in a time-series format, telling stories of individuals' performances. Then, we compared the performance outcome from this study with the outcomes from two prior studies (i.e., Jung et al., 2010 and Jung, 2014). Findings The results showed that the inclusion of goal setting into the process performance feedback solved the issue in the previous study. That was the lower than expected magnitude of performance enhancement of process performance feedback when compared to that of quantity-based feedback. It appears that goals as a motivational technique provide standards for systematic self-evaluation, serving as a cue to regulate performance behavior by strengthening the linkage between effort and performance. Thus, goals seem to set up a self-fulfilling prophecy, preconditioning better performance. However, the outcome still showed that its performance magnitude is unsatisfactory because the outcome of this study turned out to be close to the outcome of just quantity-based performance feedback in Jung et al.'s (2010) study.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.5B
• /
• pp.489-497
• /
• 2009

In the 3GPP LTE and IEEE 802.16m standardizations for IMT-Advanced, the efficient transmission of multicast and broadcast data is one of the important issues to improve system performance. Especially, to guarantee each user's QoS in the multicast group, H-ARQ or adaptive modulation are considered to be adoption, however, reduction of feedback overhead is one of the most important issues. In this paper, performance of the previously proposed OOK (On-Off Keying) based common ACK/NACK feedback channel is analyzed through theoretical analysis and simulation. Based on the results, system parameter optimization methods for common feedback channel are proposed. In addition, through computer simulation, it is shown that the common feedback method according to the proposed feedback parameter optimization can feedback ACK/NACK information for multicast H-ARQ transmission, more reliably than the conventional user dedicated feedback method in 3GPP LTE systems, and can reduce the feedback overhead as well.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.21 no.5
• /
• pp.510-518
• /
• 2010

In this paper, the designed and implemented results of CFL linearization chip which can be used in mobile radio and TRS terminal of UHF band(380~910 MHz), using $0.6\;{\mu}m$ BiCMOS process based on Si, are shown. As gain control circuits for modifying transmit power are inserted not only in feedback path but also in forward path, the stability of CFL is maintained. And, DC-offset correction function of S/H structure, which is suitable for walkie-talkie PTT operation and is easily implemented, is realized. The performance test results of transmitter show that the regulation of FCC emission mask at PEP 3 W(34.8 dBm) is satisfied when the CQPSK modulated signal is fed and more than 30 dBc improvement of 3rd order IMD is achieved when two-tone signal is inputted.

• Journal of the Korean Society of Physical Medicine
• /
• v.12 no.4
• /
• pp.105-112
• /
• 2017

PURPOSE: The purpose of this research was to know the effect of visual feedback self exercise (VFSE) on postural control in stroke patients. METHODS: 26 CVA patients were participated. The experimental group (EG) 12 (46.2%) and the control group (CG) 14 (53.8%), 17 males and 9 females. The subjects preformed VFSE on training instrument 10 minutes for 20 times in 2-3 weeks. The test was done 3 times. RESULTS: There were no statistically significant differences of the general characteristics of subjects between EG and CG by sex, affected site, muscle tone, sensory deficit, unilateral neglects, and vestibular dysfunction. The postural control effects of VFSE, in the EG showed that there were statistically significant differences among the tests during VFSE. However in the CG there were no statistically significant differences among the tests during VFSE. Also there was statistically significant difference between EG and CG after VFSE (p<.05). On the right hemiplegic EG showed that there was statistically significant difference between premid test and pre-post test after VFSE. But, the left hemiplegic EG showed that there was no statistically significant difference between before and after VFSE with all of tests. CONCLUSION: CVA patients had significant different of body weight ratio between hemiplegic side and the other side. This research suggested that CVA patients need self exercise with visual feedback for the improvement postural control ability. Therefore Physical therapist should not only prescribe hand-on exercise but also need to teach them self sensory feedback exercise to help them improve their postural control.

• Communications of Mathematical Education
• /
• v.23 no.2
• /
• pp.327-347
• /
• 2009

The purpose of the present study is to investigate the effects of mathematical communication-centered teaching using peer feedbacks on students' mathematics achievement and mathematical dispositions toward mathematics, and then this study examined the characteristics of feedbacks used by students. To do this study, two sixth grade classes selected from an elementary school in Seoul participated in the current study; one class for a treatment group applying mathematical communication-centered teaching using peer feedback, and the other for a comparison group applying traditional teaching using teacher-centered communication. The results of this study showed the fact that a treatment group of mathematical communication-centered teaching applying peer feedback scored statistically higher than a comparison group applying teacher-centered communication with respect to both students' mathematical achievement and disposition. Especially, this communication-centered teaching program focused on peer feedback was more effective to middle or lower level students than higher level students. In addition, mathematical communication-centered teaching applying peer feedbacks helps students reflect their own thinking process about problem solving, and students experienced the improvement of their confidence about mathematics from opportunities to provide peers with feedbacks. Finally, the present study suggests the important role of communication in mathematics learning, particularly student-to-student feedbacks rather than teacher-to-students feedbacks. That is to say, students need to have many opportunities to represent their own mathematical thinking processes using mathematical language.

• The Journal of Korea Robotics Society
• /
• v.12 no.3
• /
• pp.270-278
• /
• 2017

The electrical muscle stimulator (EMS) based human machine interface (HMI) free to mechanical constraint and muscle fatigue problems are proposed for force feedback in a virtual reality. The device was designed to provide force feedback up to 4.8 N and 2.6 N each to the thumb and forefingers. The main objective of the HMI is to make unnecessary mechanical structures to attach on the hand or fingers. It employs custom EMSs and an interface arranged in the forearm. In this work, major muscle groups such as extensor pollicis brevis (EPB), extensor indicis proprius (EIP), flexor pollicis longus (FPL) and flexor digitorum profundus (FDP) are selected for efficient force feedback and controlled individually. For this, a human muscular-skeletal analysis was performed and verified. The validity of the proposed multi-channel EMS based HMI was evaluated thorough various experiments with ten human subjects, interacting with a virtual environment.

• PNF and Movement
• /
• v.18 no.2
• /
• pp.173-182
• /
• 2020

Purpose: The purpose of the study was to investigate the effects of visual feedback exercise (VFE), sandal exercise (SE), and thera-band exercise (TE) on people with functional ankle instability. Methods: The 45 study participants were divided into three groups of 15. In the VFE group, participants performed short-foot exercises using visual feedback; the SE group performed sandal exercises, and the TE group performed thera-band exercises. Over a period of 8 consecutive weeks, the experimental groups exercised for 15 minutes per session, four times per week. Balance was measured using the Biodex Balance System for dynamic balance ability (overall balance index [OBI], mediolateral balance index [MBI], and anterioposterior balance index [ABI]). Vibration threshold sense (VTS) was assessed using a vibratory sensory analyzer. Ankle muscular strength was measured using the Biodex 4 Pro. The main outcome measures were assessed at baseline and after 8 weeks of training. Results: Significant improvements in dynamic balance were noted in all three groups (p < 0.05). Significant improvements in VTS and muscular strength were also noted in the VFE and TE groups but not in the SE group (p < 0.05). Conclusion: Appropriate environmental and situational mediation may be of great clinical significance for patients suffering from chronic ankle instability. It is hoped that the findings will inform a program for prevention of ankle instability.