• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.627-630
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• 2004

The PID type controller has been widely used in industrial application due to its simply control structure, ease of design, and inexpensive cost. However, control performance of the PID type controller suffers greatly from high uncertainty and nonlinearity of the system, large disturbances and so on. This paper presents a hybrid fuzzy logic proportional plus conventional integral derivative controller (fuzzy P+ID). In comparison with a conventional PID controller, only one additional parameter has to be adjusted to tune the fuzzy P+ID controller. In this case, the stability of a system remains unchanged after the PID controller is replaced by the fuzzy P+ID controller without modifying the original controller parameters. Finally, the proposed hybrid fuzzy P+ID controller is applied to BLDC motor drive. Simulation results demonstrated that the control performance of the proposed controller is better than that of the conventional controller.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2008.04a
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• pp.33-38
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• 2008

For the propagation of elastic waves in unbounded domains, absorbing boundary conditions at the fictitious numerical boundaries have been proposed. Paraxial boundary conditions(PBCs) which are kinds of absorbing boundary conditions based on paraxial approximations of the scalar and elastic wave equations not only lead to well-posed problem but also are stable and computationally inexpensive. But the complex mathematical forms of PBCs with partial derivatives complicate the application of those to finite element analysis. In this paper a penalty functional is newly proposed for applying PBCs into finite element analysis and the existence and uniqueness of the extremum of the proposed functional is demonstrated. The numerical verification of the efficiency is carried out through comparing PBCs with a viscous boundary condition.

• Carbon letters
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• v.24
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• pp.47-54
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• 2017

Different phytochemicals obtained from various natural plant sources are used as reduction agents for preparing gold, copper, silver and platinum nanoparticles. In this work a green method of reducing graphene oxide (rGO) by an inexpensive, effective and scalable method using olive leaf aqueous extract as the reducing agent, was used to produce rGO. Both GO and rGO were prepared and investigated by ultraviolet and visible spectroscopy, Fourier-transform infrared, scanning electron microscopy, atomic force microscopy, thermogravimetric analysis, cyclic voltammetry, X-ray photoelectron spectra, electrochemical impedance spectroscopy and powder X-ray diffraction.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.35 no.1
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• pp.1-10
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• 2017

An UAV (Unmanned Aerial Vehicle) is a flight system that is designed to conduct missions without a pilot. Compared to traditional airborne-based photogrammetry, UAV-based photogrammetry is inexpensive and can obtain high-spatial resolution data quickly. In this study, we aimed to classify the land cover using high-spatial resolution images obtained using a UAV. An RGB camera was used to obtain high-spatial resolution orthoimage. For accurate classification, multispectral image about same areas were obtained using a multispectral sensor. A DSM (Digital Surface Model) and a modified NDVI (Normalized Difference Vegetation Index) were generated using images obtained using the RGB camera and multispectral sensor. Pixel-based classification was performed for twelve classes by using the RF (Random Forest) method. The classification accuracy was evaluated based on the error matrix, and it was confirmed that the proposed method effectively classified the area compared to supervised classification using only the RGB image.

• Journal of the Korea Furniture Society
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• v.29 no.1
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• pp.8-17
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• 2018

Economic crisis in 2008 has changed South Korean market including furniture related field. Owing to Subprime Mortgage Crisis, new economic order, in other words, New Normal was established. Low growth rate, low interest, high unemployment rate, high risks, regulation strengthening, and all that sort of negative things have became generalized. South Korean economy has developed drastically since the Korean War, however recent economic crisis and Internet and smart phone have leading roles in shaping new consumption market. In a way, furniture market has expanded despite economic recession. Total service for housing is suited to South Korean consumers and shortened Product Life Cycle induces consumers to buy more furniture. In addition, Internet and smart phone allow people to show off their private spaces to unspecified masses. As a result, consumer prefers inexpensive and expendable furniture. It is certain that furniture market makes quantitative growth, but qualitative sides are questionable. Even though the study is focused on the existent circumstances, It will help to find out the proper ways of future furniture market in South Korea.

• Mycobiology
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• v.45 no.1
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• pp.52-56
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• 2017

In this study, we report the manganese peroxidase production ability from a Fusarium sp. strain using an inexpensive medium of agriculture residues of either rice straw or wood chips as carbon source. The highest manganese peroxidase activity on rice straw medium and on wood chips was 1.76 U/mL by day 9 and 1.91 U/mL by day 12, respectively.

• The Journal of the Korean dental association
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• v.56 no.10
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• pp.556-566
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• 2018

Whether you use a hand file or an engine-driven file, you cannot remove bacteria completely from the root canal by mechanical work alone. If the root canal is well cleaned, endodontic irrigants will well penetrate into these areas that will not be mechanically accessible. It will decompose and remove the biofilm and also remove the smear layer to reach the dentinal tubule. Clinicians who are not yet using NaOCl as their primary irrigant, should be aware that there are no other irrigants that offer all the benefits of NaOCl and are inexpensive. Clinicians may be reluctant to use it because of concern about NaOCl accident, but this possibility is extremely low if used with caution.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.152-157
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• 2001

UTC(Unglazed Transpired Collector) system has recently emerged as a new solar air heating technology. It is relatively inexpensive because it has not a glazed material. And it demonstrates efficient particularly for the applications in which larger wall area facilities with a high outdoor air requirement. Mathematical algorithm for UTC thermal modeling has been understood for further improvement of the system. EES and TRNSYS model of actual solar wall panel could be developed for computer simulations under other conditions. Computer models could be validated with the measured data from fixed outdoor test cell in KIER(Korea Institute of Energy Research). Major design parameters could be identified such as panel configuration and absorptivity and emissivity values for UTC design.

• Journal of Electrical Engineering and Technology
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• v.4 no.3
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• pp.389-395
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• 2009

Industrial motors are subject to incipient faults which, if undetected, can lead to motor failure. The necessity of incipient fault detection can be justified by safety and economical reasons. The technology of artificial neural networks has been successfully used to solve the motor incipient fault detection problem. This paper develops inexpensive, reliable, and noninvasive NN based incipient fault detection scheme for small and medium sized induction motors. Detailed design procedure for achieving the optimal NN model and Principal Component Analysis for dimensionality reduction is proposed. Overall thirteen statistical parameters are used as feature space to achieve the desired classification. GFFD NN model is designed and verified for optimal performance in fault identification on experimental data set of custom designed 2 HP, three phase 50 Hz induction motor.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.414-416
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• 2004

The intelligent PVR(Personal Video Recorder) is an enhanced PVR that provides viewers with some advanced features as well as pause, instant replay, search and skip forward found in conventional PVRs. By embedding a home server into a PVR, it is possible for an intelligent PVR to provide a powerful web-based management user interface constructed using HTML, graphics and other features common to web-browsers. When applied to other embedded systems, web technologies offer graphical user interfaces which are user-friendly, inexpensive, cross-platform and network-ready. It is the purpose of this paper to introduce implementation of intelligent PVR which is control by internet. We present the architecture of an home- server with a simple but powerful web-based network interconnection.