• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.6
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• pp.461-469
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• 2020

In this paper, we propose a PCA-based feature feedback method for extracting important areas of handwritten numeric data sets and face data sets. A PCA-based feature feedback method is proposed by extending the previous LDA-based feature feedback method. In the proposed method, the data is reduced to important feature dimensions by applying the PCA technique, one of the dimension reduction machine learning algorithms. Through the weights derived during the dimensional reduction process, the important points of data in each reduced dimensional axis are identified. Each dimension axis has a different weight in the total data according to the size of the eigenvalue of the axis. Accordingly, a weight proportional to the size of the eigenvalues of each dimension axis is given, and an operation process is performed to add important points of data in each dimension axis. The critical area of the data is calculated by applying a threshold to the data obtained through the calculation process. After that, induces reverse mapping to the original data in the important area of the derived data, and selects the important area in the original data space. The results of the experiment on the MNIST dataset are checked, and the effectiveness and possibility of the pattern recognition method based on PCA-based feature feedback are verified by comparing the results with the existing LDA-based feature feedback method.

• Transactions on Control, Automation and Systems Engineering
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• v.1 no.2
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• pp.94-98
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• 1999

Optical scanning systems use glavanometers to point the laser beam to the desired position on the workpiece. The angular speed of a galvanometer is typically controlled using Proportional+Integral+Derivative(PID) control algorithms. However, natural variations in the dynamics of different galvanometers due to manufacturing, aging, and environmental factors(i.e., process uncertainty) impose a hard limit on the bandwidth of the galvanometer control system. In general, the control bandwidth translates directly into efficiency of the system response. Since the optical scanning system must have rapid response, the higher control bandwidth is required. Auto-tuning PID algorithms have been accepted in this area since they could overcome some of the problems related to process uncertainty. However, when the galvanometer is attached to a larger mechanical system, the combined dynamics often exhibit resonances. It is well understood that PId algorithms may not have the capacity to increase the control bandwidth in the face of such resonances. This paper compares the achieable performance and robustness of a galvanometer control system using a PID controller tuned by the Ziegler-Nichols method and a controller designed by the Quantitative Feedback Theory(QFT) method. The results clearly indicate that-in contrast to PID designs-QFT can deliver a single, fixed controller which will supply high bandwidth design even when the dynamics is uncertain and includes mechanical resonances.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.433-435
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• 1993

The purpose of this study is to propose a robust OFVSCS that have the robust properties against process parameter variations and external disturbances by extending the basic OFVSCS and to evaluate its control performances. The ROFVSCS is composed of dynamic switching surfaces and output feedback switching control inputs that are constructed by the use of the unknown vector modeling technique. With the proposed scheme. existence of sliding mode is guaranteed and any nonzero bias can be suppressed in the face of disturbances and process parameter variations as far as well-known matching condition is satisfied. Due to the fact that the ROFVSCS is driven by small number of measured information, the practical application of VSCS for the systems with unmeasurable states and for high order systems. that conventional schemes cannot be applied, is possible with the proposed scheme. It is noticeable that implementation cost or VSCS can be considerably reduced without sacrifice of control performances by adopting ROFVSCS since there is no need to measure the states with high measurement cost.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.28.2-28.2
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• 2021

We investigate the impact of ram pressure stripping due to the intracluster medium (ICM) on star-forming disk galaxies with a multiphase interstellar medium maintained by strong stellar feedback. We carry out radiation-hydrodynamic simulations of an isolated disk galaxy embedded in a 1011 M⦿ dark matter halo with various ICM winds mimicking the cluster outskirts (moderate) and the central environment (strong). We find that both star formation quenching and triggering occur in ram pressure-stripped galaxies, depending on the strength of the winds. HI and H2 in the outer galactic disk are significantly stripped in the presence of moderate winds, whereas turbulent pressure provides support against ram pressure in the central region, where star formation is active. Moderate ICM winds facilitate gas collapse, increasing the total star formation rates by ~40% when the wind is oriented face-on or by ~80% when it is edge-on. In contrast, strong winds rapidly blow away neutral and molecular hydrogen gas from the galaxy, suppressing star formation by a factor of 2 within ~200 Myr. Dense gas clumps with nH≳10 M⦿ pc-2 are easily identified in extraplanar regions, but no significant young stellar populations are found in such clumps. In our attempts to enhance radiative cooling by adopting a colder ICM of T=106K only a few additional stars are formed in the tail region, even if the amount of newly cooled gas increases by an order of magnitude.

• 한국HCI학회:학술대회논문집
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• 2007.02b
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• pp.504-511
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• 2007

Webcasting which is the integration of broadcasting and communications, is a prominent service which has changed to involve bi-directional interactions between a user and a system from uni-directional communication. However almost webcasting are operating by uni-direction between living and recording currently so learners have to hear and watch a contents without their suggestion. Therefore learners can not get interaction and feedback that it may be obtain on face to face class, instructor can not ensure concentration and location of student in webcasting. This paper presents a design and development of the webcasting system based on real-time interaction which provides an environment of real-time communication between casting and learner, a fixing of students' location in order to raise a fidelity and a concentration.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1987.06a
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• pp.50-56
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• 1987

A mechanical face seal is most commonly used to seal liquids and gases at various speeds, pressures and temperatures. The primary seal ring is in sliding contact with the seal seat and as a result heat in the vicinity of the interface is generated. Local temperatures at points along the circumferential direction will fluctuate as asperities on the surfaces pass. This kind of fluctuation of temperature has been investigated to take place. This may lead to the hot spots phenomenon between the contacting asperities. Sibley and Allen showed photographic evidence of systemically moving hot spots in the contact zone. The appearance of such a temperature disturbance has been attributed to a kind of thermoelastic instabilities between two surfaces: This involves a feedback loop which comprises localized elevation of frictional heating, resultant localized thermal bulding, localized pressure increase as the result of the bulging and futher elevation of frictional heating as the result of the pressure increase. The heating of hot spots will be continued until the expanded material due to the frictional heating is worn off. Therefore to predict the speed of temperature propagation into the body is essential to the analysis of heat transfer on the edge of the seal.

• Journal of Korean Medicine Rehabilitation
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• v.28 no.1
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• pp.97-107
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• 2018

Objectives This is one of the manuals of East-West integrative medicine which was created by the committee on integrative medicine of Chung-Yeon Korean Medicine Hospital. The purpose of this manual is to support clinical decision-making and communication between Korean and western medical staff in a Korean medicine hospital during the rehabilitation of patients after knee surgery. Methods The draft was made by two rehabilitation specialists in Korean medicine. After a rehabilitation specialist in western medicine reviewed the draft and exchanged their ideas, a revised version that reflects the goal of consultation was made. Then the committee agreed to adopt the manuals through the process of review and feedback in addition to face-to-face discussions. Results This manual describes clinical decision-making for rehabilitation after arthroscopic partial meniscus resection, meniscus refixation, reconstruction of anterior and posterior cruciate ligaments. Therefore, it contains the schedule of rehabilitation treatment by the surgical technique, general goal of the rehabilitation by phase, guide for patients and postoperative infection management. Conclusions Despite some limitations, this manual has significance as the first example of a decision-making protocol suggestion for East-West integrative rehabilitation treatment after a knee surgery in one medical institution.

• Journal of Korean Medicine Rehabilitation
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• v.28 no.1
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• pp.109-120
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• 2018

Objectives This is one of the manuals of East-west integrative medicine which was created by the Committee on integrative medicine of Chung-Yeon Korean Medicine Hospital. The purpose of this manual is to support clinical decision making and communication during the rehabilitation of patients after shoulder surgery. Methods The drafting was done by two rehabilitation specialists in Korean medicine. After a rehabilitation specialist in western medicine reviewed the draft and exchanged their ideas, a revised version that reflects the goal of consultation was made. Then the Committee agreed to adopt the manuals through the process of review and feedback in addition to face-to-face discussions. Results This manual describes clinical decision making for rehabilitation after arthroscopic rotator cuff repair, SLAP repair, and arthrolysis. Therefore it contains the schedule of rehabilitation treatment through the surgical technique, general goal of the rehabilitation by phase, guide for patients and postoperative infection management. Conclusions The proposal of this manual has a significance for it provides information about decision making process and contents of treatment in one medical institution for East-west integrative rehabilitation treatment after shoulder surgery.

• Journal of Information Technology Applications and Management
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• v.14 no.3
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• pp.179-197
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• 2007

This paper analyzed the effects of interactions among participants on the satisfaction and commitment of cyber education. Even if the quality of interactions in cyber education may not be so good as that of interactions in face to face education. various kinds of interactions could be introduced in cyber education. An email or Q/A between lecturer and students could be a good way to compensate the deficiency of cyber education. Common News Boards or Discussion Rooms among students themselves are also a powerful means to learn each other in cyber space. The result of this study shows that as interactions among participants increase. satisfaction and commitment of the lecture also increase. This study also analyzed how cyber educational effects differs as interaction type changes in space dimension and time dimension. The result shows interactions in the same cyber space such as News Board brings more desirable outcome than those in the different cyber space. But the effects of interactions classified by time dimension does not show statistically significant differences.

• Journal of Korean Medicine Rehabilitation
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• v.28 no.4
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• pp.59-69
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• 2018

Objectives This is one of the manuals of East-west integrative medicine which was created by the Committee on integrative medicine of Chung-Yeon Korean Medicine Hospital. The purpose of this manual is to support clinical decision making and communication during the rehabilitation of patients after lumbar spine surgery. Methods The drafting was done by two rehabilitation specialists in Korean Medicine. After a rehabilitation specialist in western medicine reviewed the draft and exchanged their ideas, a revised version that reflects the goal of consultation was made. Then the Committee agreed to adopt the manuals through the process of review and feedback in addition to face-to-face discussions. Results This manual describes clinical decision making for rehabilitation after lumbar microdiskectomy, interbody fusion, and kyphoplasty. Therefore it contains the schedule of rehabilitation treatment through the surgical technique, general goal of the rehabilitation by phase, scales for outcome measure and postoperative infection management. Conclusions The proposal of this manual has a significance for it provides information about decision making process and contents of treatment in one medical institution for East-west integrative rehabilitation treatment after lumbar spine surgery.