• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.8 no.1
• /
• pp.249-268
• /
• 2014

Relevance feedback is an effective tool to bridge the gap between superficial image contents and medically-relevant sense in content-based medical image retrieval. In this paper, we propose an interactive medical image search framework based on pairwise constraint propagation. The basic idea is to obtain pairwise constraints from user feedback and propagate them to the entire image set to reconstruct the similarity matrix, and then rank medical images on this new manifold. In contrast to most of the algorithms that only concern manifold structure, the proposed method integrates pairwise constraint information in a feedback procedure and resolves the small sample size and the asymmetrical training typically in relevance feedback. We also introduce a long-term feedback strategy for our retrieval tasks. Experiments on two medical image datasets indicate the proposed approach can significantly improve the performance of medical image retrieval. The experiments also indicate that the proposed approach outperforms previous relevance feedback models.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.7 no.4
• /
• pp.76-85
• /
• 2008

In this paper, a 800 MHz 1 W cartesian feedback linearized power amplifier is designed and fabricated for TETRA handset application. For amplification of TETRA signal with 200 kHz narrow bandwidth, amplifier linearization performance of more than 30 dBc is improved through the cartesian feedback linearizer at the offset Sequency of ${\pm}25$ kHz. It is clear that the linearization performance is affected by imbalance of gain and phase between I/Q signals and also DC offset. The linearization performance can be maximized by the compensation of those influences. Cartesian feedback is suitable for a liearization technique of narrow band signal with QAM and another modulation signals, as well.

• The Journal of the Korea Contents Association
• /
• v.14 no.12
• /
• pp.655-664
• /
• 2014

Recently, many organizations are utilizing the team system. However, researches on a technique for efficient and effective feedback to improve a team performance is few. This study compared the relative effects of individual and group feedback on the quantity and quality of work performance. The task was to type English documents on a PC computer and both the number of words typed (quantity) and the percentage of correctly typed words (quality) were measured. Mixed design was adopted and 48 participants were randomly assigned to either individual or group feedback condition. Each group consisted of three participants and completed four sessions together. Under the individual feedback condition, each participant was provided with information on his/her own work performance, while under the group feedback condition, three participants were provided with information on their total work performance. Results showed that both feedback were effective to increase the quantity of performance. However, the effect size of treatment was more high under the group feedback than individual feedback. In addition, the accuracy of typed words was significantly improved only under the group feedback condition. Therefore, the group feedback was more effective and efficient than individual feedback to increase team performance. However, more studies are needed to generalize these results, especially, it is necessary to consider the cultural differences and type of task in the future studies.

• Physical Therapy Korea
• /
• v.27 no.2
• /
• pp.126-132
• /
• 2020

Background: Augmented somatosensory feedback stimulates the mechanoreceptor to deliver information on bodily position, improving the postural control. The various types of such feedback include ankle-foot orthoses (AFOs) and vibration. The optimal feedback to mitigate postural sway remains unclear, as does the effect of augmented somatosensory feedback on muscle co-contraction. Objects: We compared postural sway and ankle muscle co-contraction without feedback (control) and with either of two forms of somatosensory feedback (AFOs and vibration). Methods: We recruited 15 healthy subjects and tested them under three feedback conditions (control, AFOs, vibration) with two sensory conditions (eyes open, or eyes closed and the head tilted back), in random order. Postural sway was measured using a force platform; the mean sway area of the 95% confidence ellipse (AREA) and the mean velocity of the center-of-pressure displacement (VEL) were assessed. Co-contraction of the tibialis anterior and gastrocnemius muscles was measured using electromyography and converted into a co-contraction index (CI). Results: We found significant main effects of the three feedback states on postural sway (AREA, VEL) and the CI. The two sensory conditions exerted significant main effects on postural sway (AREA and VEL). AFOs reduced postural sway to a level significantly lower than that of the control (p = 0.014, p < 0.001) or that afforded by vibration (p = 0.024, p < 0.001). In terms of CI amelioration, the AFOs condition was significantly better than the control (p = 0.004). Vibration did not significantly improve either postural sway or the CI compared to the control condition. There was no significant interaction effect between the three feedback conditions and the two sensory conditions. Conclusion: Lower-extremity devices such as AFOs enhance somatosensory perception, improving postural control and decreasing the CI during static standing.

• The Korean Journal of Health Service Management
• /
• v.6 no.1
• /
• pp.117-128
• /
• 2012

This study purports to investigate the difference between upward and downward feedback and to find out the strategy to enhance the validity and reliability of the multi-source feedback system. Data were collected from 88 middle-level managers working at divisions of nursing, administration, and clinical technology at a university hospital located in north-eastern part of South Korea. Data about multi-source feedback of the year 2008 and 2009 were obtained from the department of personnel management under the permission of hospital top management. The collected data were analyzed using t-test, and correlation analysis. The major findings of the study were as follows: First, the scores of downward feedback were always higher than those of the upward feedback. Second, the scores of downward feedback were always higher than those of the upward feedback in both nursing and administrative staff, while no significant difference was found in technological staff. Third, the upward and downward feedback scores were significantly different in terms of the evaluation factors. Fourth, there were significant correlations between total scores of downward and upward feedback, and evaluation factor scores. In conclusion, the composition and weight of measurement items of multi-source feedback needs to be designed differently in terms of each job characteristics.

• Journal of the Korean Society for information Management
• /
• v.21 no.4 s.54
• /
• pp.133-152
• /
• 2004

As the Internet facilitates the rapid increase of information availability, the study on SDI service that provides users with relevant document in a timely manner has been developed. However, the practical use of this service has been low. This thesis aims at analyzing the reasons for this and developing relevance feedback based SDI system to improve the performance of the existing SDI system. Experimental systems that are developed for this study are SDI system based on users' minimum intervention feedback, SDI system based on perfect automation feedback, and SDI system based on users' maximum intervention feedback. The fourth system that utilizes the traditional SDI system is also studied to evaluate the level of performance improvement of the newly developed three types of SDI system. As a result of this study, SDI system based on users' maximum intervention feedback showed greatest performance improvement. The next performance improvement happened in order of SDI system based on perfect automation feedback, SDI system based on users' minimum intervention feedback, and the traditional SDI system. Feedback based systems showed greater performance improvement as they went through more feedback processes.

• Journal of Broadcast Engineering
• /
• v.12 no.5
• /
• pp.516-524
• /
• 2007

In order to use limited frequency resources efficiently, a single frequency network using digital on-channel repeater(DOCR) has been studied and would be implemented. The DOCR generates strong pre-ghosts to ATSC DTV receivers. The forward filter of equalizer in ATSC DTV receivers compensates the distortion made by pre-ghosts. This process induces noise enhancement and colored noise, thereby results in the performance degradation. In this paper we propose to use a dual-feedback equalizer to combat strong pre-ghosts. The proposed equalizer has two feedback filters. One is the decision feedback filter and the other is non-decision feedback filter. The additional non-decision feedback filter decreases the noise by whitening the noise and preventing the generation of colored noise in pre-ghost channel. Thus the equalization technique of dual-feedback structure has performance enhancement in pre-ghost channel in comparison with conventional decision feedback equalizer(DFE). By simulation we analyzed the performance enhancements of DTV receiver using dual-feedback equalization structure.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.9 no.6
• /
• pp.1161-1166
• /
• 2005

In this paper, for spatial multiplexing with limited feedback, we propose subspace based precoding in which the active bases are selected at the receiver from a finite number of basis sets known at both receiving and transmitting ends, conveyed to the transmitter using limited feedback, and assembled into a preceding matrix at the transmitter. The selected bases are conveyed to the transmitter using feedback information on both the index of a basis set, which indicates the most appropriate set of coordinates for describing a MIMO channel, and the active bases having the significant amounts of energy in the selected basis set. We show that the proposed subspace based precoding provides capacity similar to that of the closed-loop MIMO even with limited feedback.

• Journal of Korean Academy of Fundamentals of Nursing
• /
• v.22 no.3
• /
• pp.318-327
• /
• 2015

Purpose: The purposes of this study were to compare confidence in practice of intermittent gavage tube feeding and participants' satisfaction by three types of feedback; professor verbal feedback, professor feedback with smartphone video, and peer feedback with smartphone video. In addition, frequently failed items in the intermittent gavage tube feeding procedure were analyzed. Methods: Data were collected from a convenience sample of 78 nursing college students in November 2014. Students were randomly assigned to the control group, experimental group I (smartphone video with professor feedback) or group II (smartphone video with peer feedback). Data were analyzed using descriptive statistics including chi-square test, ANOVA, and Scheffe test with SPSS 21.0. Results: Confidence in practice of intermittent gavage tube feeding and satisfaction with feedback were highest in experimental group I that had professor feedback with smartphone video. For the procedure, the most frequently failed item was giving an explanation to patients about the purpose and the procedure of tube feeding. Conclusion: The results indicate that professor verbal feedback with smartphone video is the most benefit to the nursing students in acquiring core nursing practice skills.

• Journal of The Korean Society of Integrative Medicine
• /
• v.9 no.1
• /
• pp.133-140
• /
• 2021

Purpose: This study aimed to compare the relative muscle activity on the erector spinae, gluteus maximus, and hamstring, using a non-visual feedback bridge exercise and a visual feedback bridge exercise with a tension sensor and clinometer. Methods: Twenty-two healthy subjects participated in this study. The study subjects performed bridge exercises without visual feedback, bridge exercises using a tension sensor, and bridge exercises using an inclinometer in the supine position, and the muscle activity of the left and right erector spinae, gluteus maximus, and hamstring muscles was measured while maintaining isometric contraction during the bridge movement. Muscle activity was measured by using surface an electromyography equipment. To standardize the measured action potential of each muscle, the maximum voluntary isometric contraction was measured. The bridge exercise was repeated 3 times for 5s each. Using repeated analysis of variance, we compared the significant difference in EMG activity for each muscle between the three experiments, and all statistical processing was performed using SPSS version 26. The statistical significance level was set at α = 0.05. Results: During bridging exercises, the asymmetry of the muscle activity of the erector spinae and gluteus maximus during visual feedback guiding was lower than that during no visual feedback. However, there was no significant difference. Moreover, the asymmetry of the muscle activity of the hamstring muscles was significantly lower during tension sensor visual feedback than that during no visual feedback (p<0.05). Conclusion: These findings suggest that bridge exercise with visual feedback using a tension sensor and an inclinometer is effective in inducing symmetrical movement. When it is necessary to symmetrically adjust the weight load of both feet during the bridge exercise, it is effective to apply visual feedback using a tension sensor.