• Journal of Sensor Science and Technology
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• v.31 no.4
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• pp.260-265
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• 2022

In this study, we establish hyper-elastic haptic feedback in a virtual environment using finite element analysis techniques and develop a Force Torque (FT) sensor utilization method for application in tele-operation environments. In general, regarding haptic feedback data, in a tele-operation environment, the user is provided with feedback according to the measured force data when the model is inserted through an FT sensor. Conversely, in a virtual environment, the press-fitting model can be expressed through the spring-damper system rather than an FT sensor to provide feedback. However, unlike rigid and the elastic bodies, the hyper-elastic body represented by a spring-damper system in a virtual environment is a simple impedance model using stiffness and damping coefficients; it is limited in terms of providing actual feedback. Thus, in this study, haptic feedback was implemented using the data obtained from POD-RBF analysis results during hyper-elastic press-fitting experiments. The haptic feedback mechanism developed in this study was verified by comparing the FT sensor feedback data measured and calculated through hyper-elastic press-fitting experiments with spring-damper feedback data. Subsequently, the POD-RBF analysis feedback was compared and evaluated against the feedback mechanism of each environment through the test subject, and the similarities between the POD-RBF analysis feedback and FT sensor data feedback were verified.

• Journal of Korea Multimedia Society
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• v.21 no.11
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• pp.1353-1361
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• 2018

With the availability of real-time educational data collection and analysis techniques, the education paradigm is shifting from educator-centric to data-driven lectures. However, most offline and online education frameworks collect students' feedback from question-answering data that can summarize their understanding but requires instructor's attention when students need additional help during lectures. This paper proposes a content restructure recommendation framework based on collected student feedback. We list the types of student feedback and implement a web-based framework that collects both implicit and explicit feedback for content restructuring. With a case study of four-week lectures with 50 students, we analyze the pattern of student feedback and quantitatively validate the effect of the proposed content restructuring measured by the level of student engagement.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.5
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• pp.74-86
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• 2002

This paper proposes a VLSI architecture for high-speed data processing of the differential phase detectors with the decision feedback. To improve the BER performance of the conventional differential phase detection, DF-DPD, DPD-RGPR and DFDPD-SA have been proposed. These detection methods have the architecture feedbacking the detected phase to reduce the noise of the previous symbol as phase reference. However, the feedback of the detected phase results in lower data processing speed than that of the conventional differential phase detection. In this paper, the VLSI architecture was proposed for high-speed data processing of the differential phase detectors with decision feedback. The Proposed architecture has the pre-calculation method to previously calculate the results on 'N'th step at 'M-1'th step and the pre-decision feedback method to previously feedback the predicted phases at 'M-1'th step. The architecture proposed in this paper was implemented to RTL using VHDL. The simulation results show that the Proposed architecture obtains the high-speed data processing.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.802-807
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• 2002

The updating of FE model to match it with the experimental results needs the modal information. There are two cases where this methodology is ill-equip to deal with； under-determined and ill-conditioning problem. The feedback exciter that uses the summation of the white noise and the signals from the measurement sensors multiplied with feedback gains can deal with these problems as the new modal data from the closed loop system generate more constraints the updating parameters should obey. The new modal data from the closed loop system should be different to enhance the condition of the modal sensitivity matrix. In this research, a guide for the selection of the sensor locations and the decision of the corresponding output feedback gains is proposed. This method is based on the sensitivity of the modal data with respect to the feedback gains. Through the proper selection of the exciter and sensor locations and the feedback gain, the eigenvalue sensitivity of the updating parameters which cause the ill-conditioning of the modal sensitivity matrix can be modified and consequently the error contamination in updating parameters are reduced.

• Journal of the Korean Operations Research and Management Science Society
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• v.38 no.1
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• pp.29-44
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• 2013

This study suggests that as receiving feedback is moved back, the effectiveness of problem-solving increases. Utilizing data from innovation contests in which a number of problem solvers compete with each other, we answer questions such as whether the order of receiving first feedback affects problem-solving effectiveness and how problem-solving experience moderates the relationship between the first feedback order and problem-solving effectiveness. Empirical results based on data collected from Kaggle, an online platform for innovation contests, showed that the order that contest participants receive the first feedback increases problem-solving effectiveness. Furthermore, the more prior experience of contest participants accentuates the suggested relationship between the order of receiving the first feedback and problem-solving effectiveness.

• Journal of Sensor Science and Technology
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• v.20 no.3
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• pp.193-198
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• 2011

In this paper, we used optoelectronic feedback to generate the carrier frequency for the ASK modulation of a lighting LED. A solar cell was used for photo-detector in the feedback circuit, and the LED light was ASK modulated by controlling the ON/OFF state of the switch that is installed in the feedback loop. The oscillation frequency of the optoelectronic feedback loop was about 50 kHz and the data rate of the ASK modulation was 9.6 kbps. In experiments, the optoelectronic feedback circuit was used for the ASK modulation of a lighting LED in the transponder of a visible light identification system, and data exchange between the transponder and the reader was successfully carried out.

• The Korean Journal of Health Service Management
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• v.6 no.1
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• pp.117-128
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• 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 Data and Information Science Society
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• v.18 no.4
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• pp.1045-1056
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• 2007

We consider M/M/1 feedback queues with multi-class customers. We assume that different classes of customers have different arrival rates, service rates and feedback probabilities. Using the h-transforms of McDonald(999) we derive an importance sampling estimator for an overflow probability that the total number of customers in the system reaches a high level before emptying.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.107.6-107
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• 2002

$\textbullet$ An autonomous mobile robot was controlled through the Internet. $\textbullet$ For the direct control, the feedback data should be provided properly. $\textbullet$ Therefore, an efficient communication scheme should be defined. $\textbullet$ To overcome the transmission delay, the highly abstracted message format was used. $\textbullet$ As the feedback data, the real image sequences may suffer the transmission delay or loss of content. $\textbullet$ To resolve this, the feature information was used to construct the synthetic feedback information. $\textbullet$ By doing this, the operator could feel the hands-on control with an Internet-based robot.

• Korean Journal of English Language and Linguistics
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• v.3 no.2
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• pp.181-210
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• 2003

The purpose of the study was to investigate how Korean EFL writing instructors give feedback to their students' writing and what influences their feedback. A total of 12 Korean EFL instructors in Korean universities teaching freshman English and intermediate EFL writing courses provided their feedback given on students' writing samples and participated in interviews. Interviews were analyzed qualitatively with a constant comparative approach and some data from writing samples and questionnaires produced descriptive statistics. The first lesson from the results of the study was that grammar was still the most frequent concern in giving feedback on students' writing. Contrary to the participants' report, comments on content and organization were not produced very often. The second lesson came from the interview data. Some aspects of teacher feedback seemed mostly influenced by their beliefs on L2 writing and experience in teaching L2 writing. The final and major lesson was that teachers chose how they would give comments on students' writing depending on whether they found their feedback helpful in students learning to write. EFL writing teachers can produce effective feedback by clearly communicating their beliefs about L2 writing and criteria in their feedback to students in their EFL writing classrooms.