• International Journal of Control, Automation, and Systems
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• v.5 no.2
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• pp.117-127
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• 2007

Many real world control systems usually track several control objectives, simultaneously. At the moment, it is desirable to meet all specified goals using the controllers with simple structures like as proportional-integral (PI) and proportional-integral-derivative (PID) which are very useful in industry applications. Since in practice, these controllers are commonly tuned based on classical or trial-and-error approaches, they are incapable of obtaining good dynamical performance to capture all design objectives and specifications. This paper addresses a new method to bridge the gap between the power of optimal multiobjective control and PI/PID industrial controls. First the PI/PID control problem is reduced to a static output feedback control synthesis through the mixed $H_2/H_{\infty}$ control technique, and then the control parameters are easily carried out using an iterative linear matrix inequalities (ILMI) algorithm. Numerical examples on load-frequency control (LFC) and power system stabilizer (PSS) designs are given to illustrate the proposed methodology. The results are compared with genetic algorithm (GA) based multiobjective control and LMI based full order mixed $H_2/H_{\infty}$ control designs.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.9
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• pp.38-48
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• 2000

This paper presents the photonic bandgap structure that has a defect mode within a broad stopband. In order to create a broad stopband, we eliminated one of periodic stopbands of PBG structure by using a quarter-wavelength transformer and cascaded another PBG structure having a center frequency corresponding to the eliminated stopband. We have demonstrated that it is a simple and effective method that can solve an overlapping problem of periodic stopband in two cascaded PBG structures.

• IEMEK Journal of Embedded Systems and Applications
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• v.10 no.6
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• pp.353-362
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• 2015

In order to provide smart devices with high quality multimedia streaming services, an adaptive streaming technique over HTTP has been received much attention recently and the Dynamic Adaptive Streaming over HTTP (DASH) standard has been established. In DASH, however, the technique to select an appropriate quality of multimedia based on the performance metrics measured in a smart device might have some difficulties to reflect the capabilities of other neighboring smart devices and dynamic network conditions in real time. To solve the problem, this paper proposes a novel software agent approach, called DASH agent (DA), which gathers and analyzes the device capabilities and dynamic network conditions in real time and finally determines the highest achievable quality of segment to meet the best Quality of Experience (QoE) in current situations. The simulation results show that our approach provides higher quality of multimedia segments with less frequency of quality changes to lower quality of multimedia segments.

• Journal of electromagnetic engineering and science
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• v.6 no.4
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• pp.235-243
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• 2006

In this paper, the fractal shape is applied to microstrip band pass filters and integrated on a high-resistivity Si substrate to solve conventional $2^{nd}$ harmonic problem. Conventional microstrip coupled line filters are popular in RF front ends, because they can be easily fabricated and integrated with other RF components. However, they typically have large second harmonics that can cause unwanted interference in interested frequency bands. Without any additional filters, the proposed Koch shape filters have suppressed the $2^{nd}$ harmonics by about -40 dB, so they can be used in systems such as direct conversion receiver with stringent harmonic suppression requirements.

• The Korean Journal of Emergency Medical Services
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• v.22 no.2
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• pp.7-22
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• 2018

Purpose: This study aimed to investigate recognition, attitudes, knowledge, education experience, and education demand regarding physical restraint among laypersons. Methods: A self-reported questionnaire was completed by 105 randomly recruited laypersons in D city. Excluding 2 incomplete answers, 103 data were analyzed by frequency analysis, t-test, ANOVA, and chi-square test using SPSS 23.0. Results: Laypersons' recognition of physical restraints was rated at 3.37 out of 5 points, and showed a positive perspective. Knowledge on physical restraints was rated at 13.68 out of 18 points and was affected by age and education level (F = 2.845, p = .028)(F = 3.126, p = .029) A majority of the participants had no education on physical restraints. Nevertheless, participants showed intention to receive education in physical restraint to reach further understanding. Conclusion: Education on physical restraints is necessary for lay persons. However, there were education limits for people living in modern times. As an intervention addressing this problem, observing videos on the internet is recommended. Moreover, for advertising/educational purposes, accessing the internet and using smart-phone applications are suggested.

• Journal of Families and Better Life
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• v.25 no.1 s.85
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• pp.209-222
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• 2007

This study aimed to investigate leisure activity of the elderly, focused on the elderly education. Two hundred thirty nine elderly persons in the region of Cheongju were selected, and questionnaire was utilized for collecting data. As statistical methods, frequency, %, crosstabs analysis with spsswin was used. Five principle results emerged from this study. First, the elderly education was based on law of welfare of the aged and law of life long education. Second, the elderly education programs consist of four subcategories- intellectual, emotional, social, physical subcategories. Third, many of the elderly participated in physical subcategories. Fourth, the levels of elderly participating in leisure activity was relatively high and differed significantly according to age, time level and cause of participating in leisure activity. Fifth, they were segmented into eight groups by level of education, health and economic status. Among them, the group of positive attitudes and participated on elderly education was more likely to be higher level of education, health and economic status. Based on the results of this study, participating elderly education provides solution of problem and self development for the elderly. In order to prepare Korean society for the aged society, the government need to offer a basis on law and policy for the elderly education, as well as program the elderly education.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.3
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• pp.437-441
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• 2012

In this paper, we have designed and manufactured 10MHz power source for the application of short distance wireless power transmission. The designed power source consists of a DDS(direct digital synthesizer) signal generator, a buffer driver and a balanced power amplifier. Short range wireless power transmission is usually carried out by near-field inductive coupling between source and load. The distance variation between source and load gives rise to the change of load impedance of power amplifier, which has effect on the operation of power amplifier. To overcome this problem due to load variation of power amplifier, we have adopted the balanced power amplifier using the quadrature hybrid implemented by lumped capacitors and a mutually coupled coil. The experiment results show the above 40dBm output power, frequency range of 9 to 11MHz, and total DC power consumption of 36W.

• Journal of Korean Institute of Industrial Engineers
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• v.33 no.2
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• pp.246-253
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• 2007

All of the machines in a production line can be classified into bottleneck and non-bottleneck machines. A bottleneck is a resource whose capacity limits the throughput of the whole production facility. This paper addresses a batch sizing problem at the bottleneck machine. Traditionally, most batch sizing decisions have been made based on the EOQ (economic order quantity) model where setup and inventory costs are considered while throughput rate is assumed to be given. However, since batch size affects the capacity of the bottleneck machine, the throughput rate may not be constant. As the batch size increases, the frequency of the setup decreases. The saved setup time can be transferred to processing time, which results in higher throughput. But, the larger batch size may also result in longer lead time and larger WIP inventory level. This paper presents an alternative method to determine batch size at the bottleneck machine in a manufacturing line. A linear search algorithm is introduced to find optimal throughput rate and batch size at the same time. Numerical examples are provided to see how the proposed method works and to investigate the effects of some parameters.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.3
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• pp.7-14
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• 2004

The metal halide lamps are now widely used in the application and commercial lighting due to their attracting properties such as good color rendering and high efficiency. But, they have a serious problem of acoustic resonance using high frequency operation and they need a high voltage to ignite. So, they have not been applied to indoors. Over the past few years, a considerable number of studies have been conducted on the electronic ballast with hot restarting and resonance phenomenon. But, Very few attempts have been made at adaptive ignition method according to lamp state. In this paper is proposed electronicballast for metal halide lamps with an igniter for adaptive ignition. The proposed electronic bllast can generate a different ignition voltage according to the arc tube state.

• Journal of The Association for Neo Medicine
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• v.1 no.1
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• pp.37-44
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• 1996

This study has surveyed the problems raised through the standardization process of differentiation system and searched its solution, reaching the following conclusion. 1. The most serious problem is, most frequently occurred, an wilful application of differentiation system or constitutive classification for disease. 2. To overcome this wilfulness, we must make a definite understanding of the origin and its applicative limit of the theory. 3. And it must be preceded for a correct and objective differentiation to standardize in all choice of the differential diagnostics and its applicative condition. 4. To establish such a corresponding diagnostic scheme, it must be generally agreed on an individuality and inevitability of the suitability to differentiation principles. 5. And, though we can make a prescription through the frequency, degree, and clarified cause of the symptom, its flexibility of application must not be necessarily, ignored. 6. As this study for standardizing the disharmony between liver and pancreas(肝脾不調) shows, accordingly, we must begin by scrutinizing and defining what the chief cause, head, and inevitable symtoms are and discern them from its affinities, making necessarily a great deal attention to minute feelings and degree about its individual symptoms. On the ground of these recognition, we must go further to establish a general standardization and try to get a specific study series.