• Journal of the Korean Society of Industry Convergence
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• v.18 no.4
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• pp.224-230
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• 2015

In this paper, it is presented a learning controller for repetitive walking control of biped walking robot. We propose the iterative learning control algorithm which can learn periodic nonlinear load change ocuured due to the walking period through the intelligent control, not calculating the complex dynamics of walking robot. The learning control scheme consists of a feedforward learning rule and linear feedback control input for stabilization of learning system. The feasibility of intelligent control to biped robotic motion is shown via dynamic simulation with 25-DOF biped walking robot.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2231-2233
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• 2002

Recently NCS(Networked Control System) is widely used in distributed control system design. The insertion of the network in the feedback control loop makes the analysis and design of NCS complex. Especially, the network-induced delay can vary the system stability and even destabilizes the entire control system. This paper deals with the stability analysis method of NCS. Also, we analyze the influence of sampling period and network-induced delay on power plant stability.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.426-429
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• 2001

This paper describes a control scheme for direct torque and flux control of induction machines. The proposed predictive flux control scheme has directly calculated the reference voltage space vector based on flux errors in order to control the torque and flux. This proposed control scheme has not the requirement of a separate current regulator and proportional-integral (PI) control of the flux, torque, and/or current error, thereby improving transient performance and also has the advantage of less torque ripple in steady state with a fixed switching period. The effect of proposed method has been proven by simulations.

• Journal of Power Electronics
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• v.19 no.5
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• pp.1162-1170
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• 2019

Finite-control-set model predictive control (FCS-MPC) is a promising control scheme for two-level voltage-source inverters (TL-VSIs). However, two main issues arise in the classical FCS-MPC method: an exponentially-increasing computational time and a low steady-state performance. To solve these two issues, a novel FCS-MPC method has been proposed for n-phase TL-VSIs in this paper. The basic idea of the proposed method is to carry out the FCS-MPC scheme of TL-VSIs for one leg by one leg, like a "pipeline". Based on this idea, the calculations are reduced from exponential time to linear time and its current waveforms are improved by applying more switching states per sampling period. The cases of three-phase and five-phase TL-VSIs were tested to verify the effectiveness of proposed method.

• Earthquakes and Structures
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• v.23 no.2
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• pp.207-219
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• 2022

Seismic response control has always been a grave concern with the damage and collapse of many buildings during the past earthquakes. While there are several existing techniques like base isolation, viscous damper, moment-resisting beam-column connections, tuned mass damper, etc., many of these are succumbing to either of large displacement, near-fault, and long-period earthquakes. Keeping this viewpoint, extensive research on the application of smart materials for seismic response control of buildings was attempted during the last decade. Shape Memory Alloy (SMA) with its unique properties of superelasticity and shape memory effect is one of the smart materials used for seismic control of buildings. In this paper, an exhaustive review has been compiled on the seismic control applications of SMA in buildings. Unique properties of SMA are discussed in detail and different phases of SMA along with crystal characteristics are illustrated. Consequently, various seismic control applications of SMA are discussed in terms of performance and compared with prevalent base isolators, bracings, beam-column connections, and tuned mass damper systems.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.12 no.1
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• pp.14-26
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• 1990

This study was undertaken to observe the histopathologic changes of the extraction wounds of diabetic rats when exposed to hyperbaric oxygen. A total of 50 rats (Spraque-Dawley strain) were used, which were all induced with diabetes using streptozotocin before the experiment. The experimental group was exposed to hyperbaric oxygen at 2.5atm. for 2 hours a day during the experimental period. The obtained results were summarized as follows : 1. Severe infiltration of inflammatory cells was observed in the initial stages of both the control and experimental groups. The infiltration showed a decreasing tendency at 3rd week in the experimental group, while severe inflammatory infiltration observed in the control group during the entire experimental period. 2. There was abundant proliferation of capillary blood vessels at 1st week after extraction in the experimental group, while moderate capillary growth in the control group was observed at 1st week after extraction. 3. Osteoblastic activity was started at 1st week after extraction in the experimental group, but there showed markedly delayed appearance in the control group, which showed at 2nd week after extraction. 4. The proliferation of fibroblasts showed rather in the experimental group at 1st week, but it was moderate in the control group at 1st week, 2nd week and 3rd week. 5. Epithelialization of the extraction wound was started at 2 days after extraction and reached its peak at 3rd week in the experimental group, while control group seemed to be delayed and incompleted during the experiment. With regard to these results, hyperbaric oxygen therapy disclosed an effective results on the healing of the extraction wound in diabetic rats under exposure at 2.5 atm for 2 hours daily.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.9
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• pp.4613-4617
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• 2012

National cancer incidence data were utilized to analyze trends in esophageal cancer incidence in China in order to provide basic information for making cancer control strategy. We retrieved and re-sorted valid esophageal cancer incidence data from National Central Cancer Registry Database over 20 years period from 1989 to 2008. Crude incidence and age-standardized incidence rates were calculated for analysis, with annual percent change estimated by Joinpoint software for long term trend analysis. The crude incidence rate of esophageal cancer was found to have remained relatively stable in both urban and rural areas over the 20 year period. Age standardized incidence rate (ASR) in cancer registration areas decreased from 39.5/100,000 in 1989 to 23.0/100,000 in 2008 in all areas (AAPC=-3.3%, 95% CI:-2.8~-3.7). The trend was no change in urban areas and 2.1% average annual decrease observed in rural aras. Before the year of 2000, esophageal cancer incidence rates significant decreased with 2.8% annually and then the rates kept stable. Over 20 years from 1989 to 2008, esophageal cancer age standardized incidence rate in cancer registration areas decreased with time. However, esophageal cancer is still a big issue and efforts for control should be continuously enhanced. Cancer registration is playing an important role in cancer control with the number of registries increasing and data quality improving in China.

• Journal of muscle and joint health
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• v.6 no.1
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• pp.37-50
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• 1999

The purpose of this study was to identify the risk factors of osteoporosis. The data were collected from women who visited Physical Examination Center of a university hospital located in Taejon during the period of September 1997-August 1998. The sample was divided into two groups(the osteoporosis group of 44 cases and the control group of 66 cases). The results were summarized as follows ; 1. Sociodemographic characteristics(education and family income) and BMI showed no significant difference between the osteoporosis group and the control group. 2. There was no significant difference in coffee, unbalanced diet, diet method and meal habit between the osteoporosis group and the control group. 3. The osteoporosis group reported more incidence of operative menopause due to hysterectomy and oophorectomy, but this was not statistically significant. There was no significant difference in use of oral pill use, past disease and family history of fracture between the osteoporosis group and the control group, but the odds ratio(OR 3.11, 95% CI : 1.30-7.41) of present illness was statistically significant in the osteoporosis group. 4. There was no significant difference in the reproductive history including number of delivery and abortion and feeding method between the osteoporosis group and the control group. 5. The osteoporosis group showed significant results of lower menopausal age, shorter duration of menstruation and longer duration after menopause compared to the control group. 6. The osteoporosis group reported significantly lower level of physical activity in such variables as work activity and walking time. 7. A logistic analysis showed that shorter period of menstruation, lower level of physical activity, non-alcohol drinking group, and presence of disease were related to the possibility of occurring of osteoporosis.

• Atmosphere
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• v.26 no.4
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• pp.541-551
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• 2016

A real-time quality control algorithm for $PM_{10}$ concentration measured by Continuous Ambient Particulate Monitor (FH62C14, Thermo Fisher Scientific Inc.) has been developed. The quality control algorithm for $PM_{10}$ data consists of five main procedures. The first step is valid value check. The values should be within the acceptable range limit. Upper ($5,000{\mu}g\;m^{-3}$) and lower ($0{\mu}g\;m^{-3}$) values of instrument detectable limit have to be eliminated as being unrealistic. The second step is valid error check. Whenever unusual condition occurs, the instrument will save error code. Value having an error code is eliminated. The third step is persistence check. This step checks on a minimum required variability of data during a certain period. If the $PM_{10}$ data do not vary over the past 60 minutes by more than the specific limit ($0{\mu}g\;m^{-3}$) then the current 5-minute value fails the check. The fourth step is time continuity check, which is checked to eliminate gross outlier. The last step is spike check. The spikes in the time series are checked. The outlier detection is based on the double-difference time series, using the median. Flags indicating normal and abnormal are added to the raw data after quality control procedure. The quality control algorithm is applied to $PM_{10}$ data for Asian dust and non-Asian dust case at Seoul site and dataset for the period 2013~2014 at 26 sites in Korea.

• The korean journal of orthodontics
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• v.21 no.1 s.33
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• pp.77-96
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• 1991

Many studies has been conducted concerning prevention of unnecessary complications such as root resorption during orthodontic too th movement under various mechanical forces. Nowadays, the cause of the root resorption is not thought to be confined only to mechanical forces. But the factor that affects bone metabolism are thought to be major one of the predisposing factors. The light microscope and scanning electron microscope were used to the effects of 60 gm, and 100 gm of tipping force on root resorption of cats, which were treated with Etidronate disodium. The results were as follows: 1. In the 60gm control group, hyalinization on the compression site of periodontal ligament appeared after first week and second week. In the 60gm experimental group, it appeared after first week with low frequency. In the 100gm control group it appeared with high frequency by first and second week while in 100gm experimental group, it appeared with low frequency. 2 In the 100gm control group, resorption of the cementum and the alveolar bone rapidly increased after second week. In the 60gm experimental group, resorption or formation of alveolar bone and cementum didn't appear all through the experimental period. 3. In the 100gm control group, formation of cementum and alveolar bone appeared after first week while in the 100gm experimental group, formation of cementum and alveolar bone appeared after second week and fourth week respectively. In the 60gm control group, formation of the cementum didn't appear all through the experimental period. 4. In the control group, the root resolution of 100gm group was higher than that of 60gm group after second week, while in experimental group, root resorption didn't appear regardless of the forces.