• Journal of the Institute of Convergence Signal Processing
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• v.8 no.2
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• pp.124-129
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• 2007

Recently, the application of the linear machine for industrial field is remarkably increased, especially for the gantry machine, machine tool system and CNC. However a linear meter remains the vibrational characteristic itself therefore, In these application fields, high position control performance is essentially required in both the steady and the transient states. In this paper, the design method for a position control is proposed by using the two-degree-of freedom PID controller. This method has great features for the linear machine drives such as no over-shoot phenomena and single gain tuning strategy. By comparison with conventional PID controller, the improvement of performance of a linear motor control system using two degrees of freedom controller are discussed. Through the simulation results, the usefulness of the proposed algorithm is proved. With the simulation results, it was made clear that the introduction of two degrees of freedom controller designed by the proposed method not only improves the over shoot and starting characteristic of response but also removes the undesirable characteristic variation.

• Journal of Nutrition and Health
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• v.45 no.4
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• pp.336-346
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• 2012

This study was carried out to obtain information related to life styles, nutrition knowledge, and dietary habits according to gender and weight status of college students in Ulsan. The subjects were 324 college students (144 males, 180 females), and they were divided into three groups based on BMI. The average BMI was $21.0kg/m^2$, and the BMI of underweight, normal, and overweight students were 15.4%, 63.0%, and 21.6%, respectively. Among the male students, 0.1% and 34.0%, and among the female subjects, 27.2% and 11.7%, were included in the underweight and overweight groups, respectively. For dietary habits, the rate of skipping breakfast (34.9%) was considerably higher than those skipping lunch and dinner. Overall, the nutrition knowledge score, which was assessed by 15 questions, was somewhat low (44.9/100), yet, it was higher in females than in male students. There were significant differences among gender and weight status in several items of dietary habits such as the speed of eating meals, consuming breakfast on a regular basis, and sleeping hours. 40% of the subjects had appropriate knowledge about high calorie foods with low nutritional value. In the blood analysis of the subjects, males had higher hemoglobin levels than females. Further, more females were included in the risk group of Hb, total cholesterol, and LDL. These results suggest that in order to develop nutrition education programs for college students, differences between gender and weight status, dietary habits, and nutrition knowledge level should be considered.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.3
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• pp.207-214
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• 2017

High voltage electric power transmitter GIS(Gas Insulated Switchgear) above 72.5kV needs to satisfy domestic Korean peninsular standard(ES-6110-0002) in KEPCO with respect to normal and special operation conditions which include internal gas pressure, dead weight, wind and seismic load. Some other requirements not described in Korean standard can be applied from other international standards such as IEC(International Electronical Committee) 62271-203 and 62271-207. The GIS is a kind of pressure vessel structure made of aluminum and filled with SF6 gas of internal pressure 0.4~0.5MPa. Finite element analysis of GIS is performed with such operational loads including seismic loading and the stability and reliability is determined according to ASME BPVC(Boiler and Pressure Vessel Code) SEC. VIII standard where the allowable stress level of the pressure vessel is suggested. The result shows that the stress of GIS is satisfied the allowable stress level and the safety factor is about 2.3 for Korean peninsular standard.

• Journal of Biomedical Engineering Research
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• v.19 no.5
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• pp.503-511
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• 1998

In this study, the stress distribution for different tibial components was observed In order to Investigate the load transfer and potential failure mechanism of the tibial components subjected to dynamic impact loading and also to evacuate the effect of bone-implant bonding conditions on the implant system. The 3-dimensional finite element models included an intact tibia, cemented metal-backed tibial component, uncemented metal-blocked tibial component, cemented all-polyethylene tibial component, and metal-backed component with a debonded bone/stem interface. The results showed that the cemented metal-hocked component Induced slightly higher peak stress at stem tip than the uncemented component. The peak stress of the all-polyethylene tibia1 component at stem trip showed about half thats of metal-backed tibial components. The all-polyethylene component showed a similar dynamic response to intact tibia. In case of debonded bone/stem interface, the peak stress below the metal tray was three times Higher than that of the fully bonded interface and unstable stress distribution at the stem tip was observed with time, which causes another adverse bone apposition and implant loosening. Thus, the all-polyethylene tibial component bonded fully to the surrounding bone might be most desirable system under an impact loading.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.11
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• pp.215-222
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• 2018

In this paper, the research on the energy storage system adapting super-capacitor has been performed. The most advanced features compared to the conventional lead-acid battery systems is that it can obtain high power capability due to the super capacitor power characteristics. The suggested system can attain high power in short times and achieve high power quality improvements. The application areas are power quality improvement system, motor start power which requires high power during transient times. The energy conversion system consists of bi-directional converter and inverter and advantages of high speed, high power charging and discharging performances. The design steps for the two loop controller of the bi-directional inverter are suggested and verified by the experiment and manufacturing. The two loop controller design starts from linearized transfer function which is calculated from the state averaging model including state decoupling method. The current controller requirements are 20% overshoot and settling time and voltage controller are no overshoot and settling time which is 10 times longer than current controller. The design is verified from the step input response. The designed controllers have unity power factor characteristics and thus can improve the power quality of the grid. It also has fast response time and zero steady state error.

• Journal of Biomedical Engineering Research
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• v.22 no.5
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• pp.469-477
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• 2001

In this Paper. we describe a home health care service using electronic health questionnaires and routine checkup of vital signs Including ECG (Electrocardiography) , blood pressure. and SpO$_2$ (Oxygen Saturation) . This system is for patients at home with chronic diseases, discharged Patients, or any normal people for the Prevention of disease The service requires a home health care terminal and a PC with Interned connection installed at Patient home. The distance health care management center is equipped with a vital-sign and questionnaire interpreter as well as database, Web, and notification servers with UMS (Unified Messaging System). Participating Physician can access the servers at the center using a Web browser running on a PC available to them at any time. These components are linked together through various kinds of data and voice communication channels including PSTN (Public Switched Telephone Network) . CATV(Community Antenna TV) . Interned. and mobile communication network. Following the Physician's direction given to a Patient. he or she uses the home health care terminal to collect vital signs and fill out the questionnaire. When the terminal automatically transmits these data to the management center. the data interpreter and servers at the center process the information fo1lowing the Protocol implemented on the system. Physicians can retrieve and review data corresponding to their Patients and send back their diagnostic reports to the center. UMS at the center delivers the physician 's recommendation to the corresponding patient through the notification server. Patients can also reprieve and review their own records as well as diagnostic reports from physicians. The system Provides a new way of collecting diagnostic information and delivering doctor's recommendation to patients at home for their health management. Future works are needed in the development of new technology for measurements and interpretations of various vital signs .

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.10
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• pp.1592-1599
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• 2013

Despite numerous studies regarding overweight or obese children, only a limited number of studies have investigated the effect of underweight. The purpose of this study is to investigate the determinants of underweight among school-aged children. A total of 493 students (86 underweight and 407 normal weight students) aged 11 to 13 years were included in our study. Socio-demographic characteristics, eating habits, health information, self-perception of weight, weight-control efforts and birth-related information were collected by using survey questionnaires for children and parents. Dietary information was obtained by two 24-hour food records, which were completed by both children and their parents. The prevalence of underweight was significantly higher in girls than boys, and the frequency of medical treatment and flu symptoms were higher in underweight children than normal ones. Overall, girls tended to overestimate their own weight; this misclassification was greater among underweight girls. Birthweight was positively correlated with current weight (P<0.05) and height (P<0.01) in girls, but these correlations were not seen in boys. In conclusion, underweight girls had inappropriate self-perception of weight, and underweight in girls may be related with birthweight and inadequate dietary intakes. Therefore, it is important to build a well-designed framework that integrates efforts of home, school, and community to maintain a healthy weight with balanced diet and exercise throughout the lifetime.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.151-157
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• 2019

Recently, monitoring respiration of people has been of interest using non-invasive method. Among the vital signals usually used for indicating health status, non-invasive and portable device based monitoring respiratory status is practically useful and enable one to promptly deal with abnormal physical status. This paper proposes the approach to real-time detection of apnea signal based on Short-Time-Fourier-Transform(STFT). Contrary to the analysis of a signal in frequency domain using Fast-Fourier Transform, this paper employs Short-time-Fourier-Transform so that frequency response can be analyzed in short time interval. The respiratory signal is acquired using UWB radar sensor that enables one to obtain respiration signal in contactless way. Detection of respiratory status is carried out by analyzing frequency response, and classification of respiratory status can be provided. In particular, STFT is employed to analyze respiratory signal in real-time, leading to effective analysis of the respiratory status in practice. In the case of existence of noise in the signal, appropriate filtering process is employed as well. The proposed method is straightforward and is workable in practice to analyze the respiratory status of people. To evaluate the proposed method, experimental results are provided.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.3
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• pp.419-428
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• 2000

Multiconductor transmission line(MTL) equations are solved by FDTD(Finite-Difference Time-Domain) method to predict crosstalk and fields to transmission line coupling on lossy multiconductor transmission lines terminated in arbitrary linear loads. Skin effect losses as well as dc losses are included in the analysis. In order to increase computational efficiency, the convolution integral of internal impedance of conductors and the line currents is computed by using Prony method. For boundary conditions of MTLs terminated in linear loads, state-variable formulation is adopted. The simulated results by FDTD method are compared with the measured ones obtained by using TEM cell. The predictions are in good agreement with the measurements. In addition, it has been found that skin effect losses as well as dc losses of the conductors should be included for accurate predictions on relatively high loss transmission lines such as PCB. It has also been found that dc losses and skin-effect losses affect late-time responses and early-time responses, respectively.

• Journal of the Institute of Convergence Signal Processing
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• v.10 no.1
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• pp.93-99
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• 2009

The fuzzy control, neural network and genetic algorithm(GA) are algorithms to make the intelligence of system more higher. In this paper, we optimized the fuzzy controller using a genetic algorithm for desire response. Also a compensated fuzzy controller has dual rules. One control rule used to decrease the overshoot and rise time occurring in transient response region and another fuzzy control rule use to decrease the steady state error and rapildy to converge at the convergence region. GA is necessary to optimal the exchange time of the two fuzzy control rule base. Fuzzy-GA controller have a process of reproduction, crossover and mutation and we experimented by hydraulic servo motor control system We could observe that compensated Fuzzy-GA controller have good control performance compare to the fuzzy control technique have two rule base table.