• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.422-427
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• 2006

This paper presents force-feedback control performance of a haptic device in virtual environment of minimally invasive surgery(MIS). As a first step, based on an electrorheological(ER) fluid and spherical geometry, a new type of master device is developed and integrated with a virtual environment of MIS such as a surgical tool and human organ. The virtual object is then mathematically formulated by adopting the shape retaining chain linked(S-Chain) model. After evaluating reflection force, computational time, and compatibility with real time control, the virtual environment of MIS is formulated by interactivity with the ER haptic device in real space. Tracking control performances for virtual force trajectory are presented in time domain, and theirtrackingerrorsareevaluated.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.12 s.117
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• pp.1286-1293
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• 2006

This paper presents force-feedback control performance of a haptic device in virtual environment of minimally invasive surgery(MIS). As a first step, based on an electrorheological (ER) fluid and spherical geometry, a new type of master device is developed and integrated with a virtual environment of MIS such as a surgical tool and human organ. The virtual object is then mathematically formulated by adopting the shape retaining chain linked(S-chain) model. After evaluating reflection force, computational time, and compatibility with real time control, the virtual environment of MIS is formulated by interactivity with the ER haptic device in real space. Tracking control performances for virtual force trajectory are presented in time domain.

• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.255-258
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• 2003

TCP is taking over 95％ among the Internet traffics. Recently the demands of multimedia services in the Internet has been increasing. These multimedia services mostly need real-time deliverly, and then RTP has been a de facto to transmission protocol for these real-time multimedia services. RTP uses UDP as its underlying transport protocol, and thus it does not support any rate and congestion control. Thus, for fair use of the Internet bandwidth with TCP traffics. RTP also needs a rate control. One constraint of RTP is that the feedback information(delivered by, RTP's twin protocol, RTCP) is recommended to be sent no less than 5 seconds. In this paper, we propose a TCP-friendly RTP rate control which use only RTCP feedback information at every 5 seconds. The experiment results show that our proposed algorithm works. But, it is found that we need more time to test the effects of parameters and policies of the algorithms, which will be reported later.

• Journal of Aerospace System Engineering
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• v.10 no.1
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• pp.29-34
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• 2016

Flutter wind-tunnel test is an expensive and complicated process. Also, the test model may has discrepancy in the structural characteristics when compared to those of the real model. "Dry Wind-Tunnel" (DWT) is an innovative testing system which consists of the ground vibration test (GVT) hardware system and software which computationally can be operated and feedback in real-time to yield rapidly the unsteady aerodynamic forces. In this paper, we study on the aerodynamic forces of DWT system to feedback in time domain. The aerodynamic forces in the reduced-frequency domain are approximated by Minimum-state approximation. And we present a state-space equation of the aerodynamic forces. With the two simulation model, we compare the results of the flutter analysis.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2540-2545
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• 2003

We propose a new technique to the design and real-time implementation of an adaptive controller for robotic manipulator based on digital signal processors in this paper. The Texas Instruments DSPs(TMS320C80) chips are used in implementing real-time adaptive control algorithms to provide enhanced motion control performance for dual-arm robotic manipulators. In the proposed scheme, adaptation laws are derived from model reference adaptive control principle based on the improved direct Lyapunov method. The proposed adaptive controller consists of an adaptive feed-forward and feedback controller and time-varying auxiliary controller elements. The proposed control scheme is simple in structure, fast in computation, and suitable for real-time control. Moreover, this scheme does not require any accurate dynamic modeling, nor values of manipulator parameters and payload. Performance of the proposed adaptive controller is illustrated by simulation and experimental results for a dual arm robot consisting of two 4-d.o.f. robots at the joint space and cartesian space.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.741-746
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• 2004

We propose a new technique to the design and real-time implementation of an adaptive controller for robotic manipulator based on digital signal processors in this paper. The Texas Instruments DSPs(TMS320C80) chips are used in implementing real-time adaptive control algorithms to provide enhanced motion control performance for dual-arm robotic manipulators. In the proposed scheme, adaptation laws are derived from model reference adaptive control principle based on the improved direct Lyapunov method. The proposed adaptive controller consists of an adaptive feed-forward and feedback controller and time-varying auxiliary controller elements. The proposed control scheme is simple in structure, fast in computation, and suitable for real-time control. Moreover, this scheme does not require any accurate dynamic modeling, nor values of manipulator parameters and payload. Performance of the proposed adaptive controller is illustrated by simulation and experimental results for a dual arm robot consisting of two 4-d.o.f. robots at the joint space and cartesian space.

• 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.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.352-357
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• 1987

The Auto Tuning Controller is designed using Fuzzy set theory. And to verify its validity it is Applied to the Auto Tuner of hydraulic Control System. Fuzzy Tuning Procedures are written by linguistic model and translated into C language formation by preprocessor. Then it is executed with state feedback controller in real time, Fuzzy Logic Controller adjusts state feedback gain by proper tuning logic in each step to satisfy the desired maximum overshoot and settling time.

• Proceedings of the KIEE Conference
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• 1981.07a
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• pp.146-153
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• 1981

A practical and robust control scheme is suggested for MIMO discrete time processes with real simple poles. This type of control scheme, having the advantages of both the adaptiveness and optimality, may be successfully applicable to structured dynamic controllers for plants whose parameters are slowly time-varying. The identification of the process parameters is under-taken in ARMA form and the optimization of the feedback gain matrix is performed in the state space representation with regard to a standard quadratic criterion.

• The Korean Journal of Emergency Medical Services
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• v.15 no.2
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• pp.101-108
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• 2011

Purpose: Cardiopulmonary resuscitation (CPR) prevents tissue necrosis of the brain and cardiac muscle in the cardiac arrest patient and requires exact skills in order to increase survival rate. Through comparison of the training effects of feedback manikin and non-feedback manikin, this study present the effective CPR device to CPR instructors. Method: This CPR course for 80 students by using Resusci Anne $SkillReporter^{TM}$ (RASR; Laerdal Medical, Stavanger, Norway) and Actar 911 $Squadron^{TM}$ (A911; Vital Signs, New Jersey, USA) held on December 22, 2009. Thirty seven students and two assistants were placed in one laboratory, there were five RASR manikins which provide the LED performance indicator, not the metronome. Forty two students and two assistants were placed in the other laboratory, there were 20 A911 manikins which don't provide any feedback indicator. Chest compression scores and ventilation compression scores obtaining from two groups were analysed statistically by using independent t-test. Results: Chest compression scores, average depth (mm) was 37.5 in RASR and 41.80 A911 (p=.004), too depth (#) was 2.8 in RASR and 19.4 A911 (p=.005), average number per min (#/min) was 64.4 in RASR and 68.2 A911 (p=.038), wrong hand position (#/min) was 10.9 in RASR and 30.8 A911 (p=.040). Four items that showed better scores in group RASR had statistically significant difference. Ventilation compression scores, percent correct (%) was 40.6 in RASR and 20.6 A911 (p<.001), number correct (#) was 4.7 in RASR and 2.1 A911 (p=.002), too fast (#) was 0.9 in RASR and 2.9 A911 (p=.003), average volume (ml) was 536.5 in RASR and 707.1 A911 (p=.011). Also, three items that showed better scores in group RASR had statistically significant difference. Conclusions: Regarding the positive effect of CPR training feedback, comparison between the real-time visual feedback manikin (RASR) and the non-feedback manikin (A911) showed that RASR had better results than A911 in chest compression except average number per min (it means that we need harder chest manikin) and ventilation. Verification of the training effect in the real world such as CPR outcomes is also necessary. A proper application of manikin in training circumstances and research on retention of CPR skills will be needed.