• Journal of Technologic Dentistry
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• v.42 no.2
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• pp.187-195
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• 2020

Purpose: The purpose of this study is to examine decision factors to start orthodontic treatment with male and female undergraduates having experience in orthodontic treatment at a dental clinic or hospital because of malocclusion. Methods: A survey was carried out to investigate decision factors to begin orthodontic treatment with 330 male and female undergraduates attending universities located in Daegu Metropolitan City or Gyeongsangbuk-do who had experience in orthodontic treatment at a dental clinic or hospital because of malocclusion, and out of 330 questionnaire sheets, total 294 (89.1%) sheets were employed for analysis after excluding ones unreliably or erroneously answered. Results: According to the results of analyzing decision factors for orthodontic treatment, such factors as 'a dentistry-related person's suggestion', 'feeling necessity on one's own' are found to be significantly higher in students majoring in health units than those having non-dental health majors, and students residing in small and medium cities are influenced more significantly by this decision factor, 'an acquaintance's suggestion', than those living in farming and fishing villages or big cities, and students who started orthodontic treatment at elementary school were more significantly influenced by the factor, 'feeling necessity through the public media'. Conclusion: Among the factors influencing their decision on orthodontic treatment, no influence was found in sexual difference, and each of the decision factors influenced them considerably according to the difference of their residence, economic power, majors, or time to start orthodontic treatment.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.252-257
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• 2000

This paper describes a look-ahead algorithm of PCNC(personal computer numerical control). The algorithm is based on acceleration/deceleration before interpolation never including a command error and determines a velocity value in end point of each block(or start point of each block). The algorithm is represented as following; 1) calculating two maximum arrival velocity(v1, v2) by a acceleration value, a command velocity and distance in a previous block and a next block, 2) getting a tangent velocity(v3) of the adjacent blocks, 3) choosing a minimum value among these three velocities, and 4) setting the value to a velocity of a start point of the next block(or a end point of the previous block). The proposed look-ahead algorithm was implemented and tested by using a commercial RTOS(real time operation system) on the MS-Windows NT 4.0 in a PC platform. For interfacing to a machine, a counter board, a DAC board and a DIO board were used. The result of the algorithm increased a machining precision and a machining speed in many short blocks.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.1
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• pp.196-202
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• 2002

In this work, we propose a new type of HDD suspension featuring shape memory alloy (SMA) actuator in order to prevent the contact between the slider and disk. The principal design parameters are obtained from the modal analysis using finite element analysis, and then the dynamic model is established to formulate the control scheme for Non-Contact Start/stop mode drive. Subsequently, a robust H$\_$$\infty$/ control algorithm is designed by integrating experimentally-Obtained SMA actuator dynamics to the proposed HDD suspension system. The controller is empirically realized and control results for the load/unload profiles are presented in time domain. In addition, the contact signal between the slider and disk is measured by the electrical resistance method.

• Journal of Korea Water Resources Association
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• v.37 no.2
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• pp.121-131
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• 2004

SIMHYD and TANK model are used to predict time series of daily rainfall-runoff of Soyang Dam and Youngcheon Dam watershed. The performances of SIMHYD model with 7 parameters and TANK model with17 parameters are compared. Three optimization methods (Genetic algorithm, Pattern search multi-start and Shuffled Complex Evolution algorithm) were applied to study-areas with 3 different types of objective functions. Efficiency of TANK model is higher than that of SIMHYD. Among different types of objective function, Nash-sutcliffe coefficient is found to be the most appropriateobjective function to evaluate applicability of model.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.5
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• pp.395-403
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• 2020

This study presents a stable start-up strategy for v/f scalar-controlled permanent magnet synchronous motors (PMSMs). The v/f-controlled PMSMs easily lose synchronism under low-speed conditions if an insufficient stator voltage is applied to the machine due to errors in measured motor parameters and inverter nonlinearity, such as inverter dead time and on-state voltage drop. The proposed method adopts the I/f control method to ensure a stable start at low speeds and then switches to the v/f control method at medium speeds. A smooth transition method from I/f control to v/f control is proposed to minimize the oscillation of the stator current and rotor speed during transition. Moreover, the stability of the I/f and v/f control methods is analyzed using a small-signal model. Simulation and experimental results are provided to verify the performance of the proposed control strategy.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.6
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• pp.71-81
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• 2000

This paper describers a look ahead algorithm of PC-NC(personal computer numerical control). The algorithm is based on acceleration/deceleration before interpolation which doesn\`t include a command error and determines a feedrate value at the end point of each block(or start point of each block). The algorithm is represented as following; 1) calculating two maximum arrival feedrates(F$_1$,F$_2$) by an acceleration value, a command feedrate, and the distance of a NC block, 2) getting a tangent feedrate (F$_3$) of the adjacent blocks, 3) choosing a minimum value among these three feedrates, and 4) setting the value to a feedrate of a start point of the next block(or a end point of the previous block). The proposed look ahead algorithm was implemented and tested by using a commercial TROS(real time operation system) on the MS-Windows NT 4.0 in a PC platform. For interfacing to a machine, a counter board, a DAC board and a DIO board were used. The result of the algorithm increased a machining precision and a machining speed in many short blocks.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.9
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• pp.1119-1124
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• 2018

So far BESS(Battery Energy storage system) has been widely applied to power systems rapidly. Usually it has been used to regulate the renewable energy output and to adjust the power system frequency. In 2013, EPRI has reported a study of utilizing BESS to replace two black start generators of American Electric Power(AEP) that will be demolished. If the BESS can be used as a self-starting generator, it is possible to shorten the long-distance primary transmission line and shorten the restoration time because BESS is capable of the high-speed start and there is no restriction on the installation position. This paper presents a possibility of using BESS as a self-starting generator by using PSCAD/EMTDC in Korean power systems. Herein, the process to estimated the required capacity of BESS is also presented.

• Journal of Technologic Dentistry
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• v.25 no.1
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• pp.203-218
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• 2003

The 3 year graduate school course of the dental technician, which has been enforced since 1994 till the present date, differs from the currently existing 2 year graduate course because of an 8 weeks clinical field training course being newly executed and an imposed curriculum about manufacturing specialized prosthetics like all-ceramic, double prosthetic technology, attachment, and implant. Even though nearly 10 years have passed, the education program of the 18 colleges have still not been standardized and the subjects differing a little, while some are still not following the 3 years graduate course. The goal of this research is to emphasize the qualities of the 3 years graduate program and enable the dental technician to handle clinical models in the dental technical clinic right after graduation by adding clinical field training in the dental technician education program of the 18 colleges. Also in accordance to a national and international increase in esthetical prosthetics, credits, weekly study hours, education practice time of specialized prosthetic dental technology can be analyzed as follows. 1. In the year 2003, currently colleges start clinical practice education starting from the 1st semester of the 2nd year junior year, to the 2nd semester of 3rd year the varying in time with adequate class time, and credits. The average credit is 9.56, and weekly average class time is 18.00 hours. later clinical trainee education will be adjusted to the 3 year graduate school course to 10 credits and 20 hours and the adequate education period should be the 2nd semester of 3rd grade when most basic clinical education has been covered. 2. Currently in the year 2003, all-ceramic education has an average credit of 8.01 in 17 colleges with an exception of Ma-san college. The weekly average theoretical education is 4.94 hours, weekly clinical education of 7.88 hours and currently in 14 colleges porcelain technical class usually starts in the 1st semester of the 2nd year. All-ceramic education is thought to have adequate credits, timing, and weekly study hours. 3. Currently in 2003 implant education is enforced in 11 colleges including Bu-san Catholic university and the education period is usually in the 3rd year. Out of the 11 colleges, only Bu-san Catholic univ., Ma-san and Shinheung college have practice training classes. We knew that Shingu, Dongu, Mokpo science colleges have practice training as a curriculum, namely specific prosthetics laboratory. Out of the 9 colleges enforcing implant education the average credits taken are 2.56, and the average hours of weekly theory education is 2.14, but with the exception of Shinheung college which has an implant practice training course theory and practice classes are not divided. Therefore implant education is thought to start in the 3rd year as a 3 credit course with 3 hours of theory and practice each. 4. Currently in 2003, theoretical attachment education is given in 15 colleges and including practical training it is given in 10 colleges. The education starts 1st semester of the 2nd year till the 2nd semester of the 3rd year. The average credit of attachment theory education in the 15 colleges was 3.64, the average weekly theoretical education was 2.64, and the average weekly practice training out of the schools teaching it was 3.20. Later attachment education is thought to start the 1st semester of the 3rd year as a 3 credit course with 2 hours of theory class and 3 hours of practice training. 5. Double prosthetic technology is currently carried out in Dae-jon Health Science college(2nd year 2nd semester, 2 credits, theory 2hours), Gimcheon college (1 credit, 2 hours of practical training), Bu-san Catholic university (4th year 2nd semester, 4 hours of theory. practice). When the 3 year course is enforced, education will start 1st semester of the 3rd year with 2hours of theory and practice each. 6. The newly installed programs of the 3 year education is clinical field training, and specialized prosthetic manufacturing practice like all-ceramic, double prosthetic technology, attachment, and implant. If such education is to be effectively managed, a primary precursor as systemic basic clinical education is thought to be important. 7. Nationally in the 18 colleges of dental technology the currently executed curriculum course had varying subjects, class time according to the subject, and credits by each college. The curriculum difference between the colleges must be settled.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.4
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• pp.112-122
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• 1999

In realistic control systems the nonlinear saturation attributes of the control actuator due to physical limitations should be taken into account This nonlinear saturation of actuators may cause not only deterioration of the control performance but also a large overshoot during start-up and shut-down. As the overshoot increases the system may become oscillatory unstable. in this paper the supervisor implementation which guarantees good performance for saturation operation and prevents reset wind up is presented, Moreover the sufficient conditions of the stability for saturated system using supervisory control with a dynamic controller are provided in the continuous-time and in the discrete-time domain Numerical example is illustrated to depict the efficiency of supervisory control for a typical satuaurated production-distribution system controlled by a discrete-time dynamic controller and to validate basic results by simulation.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.2
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• pp.197-203
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• 1997

In this paper, we present a GP-PID(Generalized Predictive PID) controller which has the same structure as a generalized predictive control with steady-state weighting. The proposed controller can perform better than the conventional PID controller because it includes intrinsic delay-time compensator. The PID tuning parameters and delay-time compensator are calculated by equating the two degree of freedom PID to a linear form of GPC. The proposed controller is combined with a supervisor for safe start and self-tuning. GP-PID controller has been tested for various numerical models and an experimental stirred tank heater. As a result, it was observed that the proposed controller shows a satisfactory performance for variable delay as well as stochastic disturbance.