• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.1A
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• pp.77-83
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• 2004

Parallel coupled microstrip bandpass filter is widely used in microwave circuits. But this filter limits the filter applications because of the narrow bandwidth and the spurious passband at twice the basic passband frequency. In order to solve this problem, a method of the asymmetrical coupled microstrip lines on composite dielectric substrate is presented. Closed form method is used to analyze the asymmetrical coupled microstrip lines on composite dielectric substrate. An experimental filter is fabricated over $33\%$ bandwidth centered at 9GHz. Compared with the filter on a single substrate, this filter on composite substrate shows improvement of the spurious passband.

• Korean Journal of Health Education and Promotion
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• v.22 no.1
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• pp.41-54
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• 2005

Purpose : This study was undertaken in order to find out the actual condition and barriers of health education in elementary school after introduction of 7th curriculum modification. Method: A questionaire was sent by mail on November 1, 2003, and received a total of 230 till November 30, 2003. Among them, 198 were included in fmal analysis. The collected data was analyzed through frequency, percentage, mean and standard deviation. Results : The results of this study were as follows: Among of the school health task, the most time spending task was emergency treatment and medication. The health education content which now being taught was sex education and prevention of drug abuse in the 6th grade, prevention of obesity in the 5th grade, emergency treatment, safety education in the 4th grade and prevention of disease of teeth in the 3rd grade. The most difficult problem in health education was pointed to no subject, no hour about health education by policy. Conclusion : It was necessary to formalize the health education subject, to ensure of health education hour by policy and to establish of extra health education room to improve health education at elementary school.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.11a
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• pp.9-10
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• 2011

Domestic construction industry suffered from the IMF and makes a great effort to improve in 'cost management', 'strengthening the competitiveness of the construction industry'. Therefore, the industry has become interested in improving the productivity of construction and ongoing research is being progressed in various angles. In such circumstances, the needs for a study of concepts and space of the actual construction work place is emerging. This study were utilized BIM to understand the types and causes of problems in space during the finishing work in construction and categorize importance and frequency of occurence through a survey of experts and AHP to analyze the realtive effects of importance then modeling to them to aware of issues and give direction for efficient management. This study is anylize the problem which is caused by same time process in finishing work progress of apartment applied by BIM. and categorize the type of work interference management in finishing work, and anylize by the type of occurence then predict the work interference management through in BIM 3D VIEW and suggest the solutions.

• Journal of Communications and Networks
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• v.10 no.2
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• pp.118-126
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• 2008

The use of beamforming is effective for users in limited power environments. However, when it is applied to the downlink of a cellular system with universal frequency reuse, users near the sector boundary may experience significant interference from more than one sector. The use of a minimum mean square error (MMSE)-type receiver may not sufficiently cancel out the interference unless a sufficient number of receive antennas are used. In this paper, we consider the use of inter-sector beamforming that cooperates with a neighboring sector in the same cell to mitigate this interference problem in time-division duplex (TDD) environments. The proposed scheme can avoid interference from an adjacent sector in the same cell, while enhancing the transmit array gain by using the TDD reciprocity. The performance of the proposed scheme is analyzed in terms of the output signal-to-interference-plus-noise power ratio (SINR) and the output capacity when applied to an MMSE-type receiver. The beamforming mode can be analytically switched between the inter-sector and the single-sector mode based on the long-term channel information. Finally, the effectiveness of the proposed scheme is verified by computer simulation.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.12
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• pp.691-699
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• 2004

SRM(Switched Reluctance Motor) drives require the accurate position information of the rotor. These informations are generally provided by a tacho generator or digital shaft-position encoder These speed sensors lower the system reliability and require special attention to noise. This paper describes a new approach to estimating SRM speed from measured terminal voltages and currents for speed sensorless control. The described method is based on the sliding mode observer. The rotor speed and position observers are estimated by the adaptation law using the real and estimated currents. However, the conventional adaptive sliding mode observer based on the variable structure control theory has some disadvantages that the estimated values including the high-frequency chattering and the steady state error generated due to the infinite feedback gain chosen and the discontinuous control input. To reduce the chattering and steady state error, an integrator is also inserted in the sliding mode observer strategy. The described adaptive sliding mode observer decreases the vibration to the switching hyper-plane of the sliding mode by adding integrator. The described methodology incorporates the Lyapunov algorithm to drive the rotor speed and the stator resistance such that it can overcome the problem of sensitivity in the face of SRM parameter variation. Also, without any mechanical information. The rotor speed of SRM is obtained form adaptive scheme. The described method is verified through the simulation and experiment.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.12
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• pp.1259-1263
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• 2004

In this paper, the optimum design of ultrasonic dry cleaning head was investigated. The transducer instead of mechanical dynamic structure was used to generate ultrasonic wave and the horn-shape amplifier was utilized to solve the energy decaying problem of ultrasonic wave with propagating it through the media. The analyses of ultrasonic wave and a fluid for the selected structure of a cleaning head were carried out using SYSNOISE and ANSYS simulators, respectively. Based on simulator results, the distance between a horn and the substrate of 4 mm and the horn diameter of 10 mm were determined to maximize the energy of ultrasonic waves. The cooling structure was also considered to reduce the heat from the transducer and the horn. The equivalent circuit for the fabricated horn was deduced from HP4194A impedance/gain/phase analyzer and the frequency of an ultrasonic wave of 20.25 kHz was confirmed using the parameters of the equivalent circuit.

• IEMEK Journal of Embedded Systems and Applications
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• v.14 no.6
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• pp.287-294
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• 2019

With the automation of production lines in the manufacturing industry, the importance of real-time fault diagnosis of facility is increasing. In this paper, we propose a fault diagnosis algorithm of LM (Linear Motion)-guide based on deep learning using vibration signals. Generally, in order to guarantee the performance of the deep learning, it is necessary to have a sufficient amount of data, but in a manufacturing industry, it is often difficult to obtain enough data due to physical and time constraints. To solve this problem, we propose a convolutional neural networks (CNN) model based on transfer learning. In addition, the spectrogram image is input to the CNN to reflect the frequency characteristic of the vibration signals with time. The performance of fault diagnosis according to various load condition and transfer learning method was compared and evaluated by experiments. The results showed that the proposed algorithm exhibited an excellent performance.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.20 no.2
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• pp.35-42
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• 2014

Background: The purpose of this study was to effect of the manual therapy and pelvic floor muscle exercise interventions in patient with acute lumbar sprain. Based on this, proceed to present an effective physical treatments. Methods: Subject was 55 year old female patient with acute lumbar sprain. Subject was damaged, wash in the morning. Subject was hoping to return to work and Activity daily living (ADL) without pain. I proceed in order screening, evaluation, diagnosis, prognosis, treatment planning and intervention, re-screening. To solving problem, was conducted in parallel to a manual therapy and therapeutic exercise. Results: To investigate changes in body functions and activities was measured, Visual analog scale (VAS) and Oswestry disability index (ODI), changes in posture, maintain in posture, 10m walk test. The improved results were compared before and three weeks after mediation interventions. Conclusions: Frequency manual therapy and pelvic floor muscle exercise is thought to be an efficient way of patients with acute lumbar sprain.

• The Journal of Korean Academy of Prosthodontics
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• v.39 no.6
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• pp.625-632
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• 2001

Statement of Problem. Objective and quantitative measurement of implant stability is very important from implant installation to long-lasting maintenance period thereafter. Purpose of study. This study was to evaluate and compare two ISQ and PTVs on the implant stability measurements according to the increased effective implant length. Materials and methods. Twenty self-tapping fixtures were installed in the bovine scapula and in 10 of those for group I, ISQ and PTVs were obtained in the vertical/horizontal directions according to the increased effective implant length using $Osstell^{TM}$ and $Periotest^{(R)}$. After stability measurement, removal torques were measured between the after installation and after thread exposure group. Results. ISQ and PTVs showed decreased and increased values according to the increased abutment length. Apart from PTVs, ISQ values were shown higher in horizontal direction to the long axis of bone in both the after installation and the after thread exposure groups. Removal torque values were shown higher in after installation group. Conclusion. From the results of this study, implant stability measurement using resonance frequency analysis was more sensitive and discriminative than PTVs measurement.

• 한국전산유체공학회:학술대회논문집
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• 2008.03a
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• pp.159-165
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• 2008

A sirocco fan is widely used for discharging pollutants of a kitchen space since it is able to generate a relatively high air flow rate considering its small size and makes less noise than a axial fan or a centrifugal fan. However, it has a problem because its efficiency is low, and power consumption is larger. Performance of a sirocco fan is influenced by various factors such as number of the fan blades, diameter of the fan, geometry of the fan, geometry of its housing, revolution frequency, static pressure condition, and etc. This research investigated the effect on the performance of geometry of the housing. For CFD analysis, we used a commercial code, SC/Tetra, and used a sliding mesh method to give the same condition as an actual state. Verification of the CFD results is done by comparison of experimental data and numerical one about the suction flow rate, and it is confirmed that two results are well consistent. After we changed the shape of housing according to Archimedes' screw, we observed that suction efficiency is improved by 10.7% maximum.