• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.4B no.4
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• pp.217-224
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• 2004

A novel anti-islanding method for the distributed power generation system (DPGS) is proposed in this paper. Three different islanding scenarios are explored and presented based on the analysis of real and reactive power mismatch. It is shown via investigation that islanding voltage is a function of real power alone, where its frequency is a function of both real and reactive power. Following this analysis, a robust anti-islanding algorithm is developed. The proposed algorithm continuously perturbs ($\pm$5%) the reactive power supplied by the DPGS while simultaneously monitoring the utility voltage and frequency. In the event of islanding, a measurable frequency deviation takes place, upon which the real power of the DPGS is further reduced to 80%. A drop in voltage positively confirms islanding and the DPGS is then safely disconnected. This method of control is shown to be robust: it is able to detect islanding under resonant loads and is also fast acting (operable in one cycle). Possible islanding conditions are simulated and verified through analysis. Experimental results on a 0.5kW fuel cell system connected to a utility grid are discussed.

• Journal of Ship and Ocean Technology
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• v.3 no.4
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• pp.1-14
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• 1999

The improved Green integral equation using the Kelvin-type Green function in known free of irregular frequencies where the integral over the inner free surface integral is removed from the integral equation, resulting in an overdetermined integral equation. The solution of the overdetermined Green integral equation is shown identical with the solution of the improved Green integral equation Using the B-spline higher order panel method, the overdetermined equation is discretized in two different ways; one of the resulting linear system is square and the other is redundant. Numerical experiments show that the solutions of both are identical. Using the present methods, the exact values and higher derivatives of the potential at any place over the wetted surface of the body can be found with much fewer panels than low order panel method.

• Journal of the Korean Institute of Rural Architecture
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• v.6 no.1
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• pp.13-20
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• 2004

Museums have conducted the role of conserving, collecting, and displaying cultural property generally but main museum function transforms the role of social educational place accomplishing various instruction programs .recently through social perception's changing. Educational function of museum having experience program is more effect than before that. Museums need exhibition for preservation of property in regional community and history, as well as certainly require the concept to importing experience program. Through analysing experience program patterns and varieties in domestic museum. I will propose basic dater to supply preliminary and intermediate study.

• Journal of the Korea Concrete Institute
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• v.12 no.2
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• pp.79-87
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• 2000

The strength development of concrete is influenced by temperature and cement type which greatly affect hydration degree of cement. There is not pertinent concrete strength management methods for estimating the in-place strength of concrete. One such method is the maturity concept. The maturity concept is based on the fact that concrete gains strength with time as a result of the cement hydration and, thus the rate of hydration, as in any chemical reaction, depends primarily on the concrete temperature during hydration. Thus, the strength of concrete is function of its time-temperature history. This goals of the present study are to investigate a relationship between strength of high-fluidity concrete and maturity that is expressed as a function of an integral of the curing period and temperature, predict strength of concrete.

• Journal of Communications and Networks
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• v.12 no.5
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• pp.399-405
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• 2010

Blind equalization techniques have been used in broadcast and multipoint communications. In this paper, two criteria of minimizing Euclidian distance between two probability density functions (PDFs) for adaptive blind equalizers are presented. For PDF calculation, Parzen window estimator is used. One criterion is to use a set of randomly generated desired symbols at the receiver so that PDF of the generated symbols matches that of the transmitted symbols. The second method is to use a set of Dirac delta functions in place of the PDF of the transmitted symbols. From the simulation results, the proposed methods significantly outperform the constant modulus algorithm in multipath channel environments.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.12
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• pp.1245-1250
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• 2016

In this study, smart laser pointer using image processing was studied. The laser pointer tracked the light by using image processing. and the tracking signal was received to the transmitting unit. Smart laser pointer received the video signal have function of erase, write convert window, and changing of font color. It was studied that the smart laser pointer system could run pointer and mouse function on the one place.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.279-283
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• 2001

We described an integrated management system, which is a design system of suction muffler(SMDS). SMDS constructs a virtual design system and possesses a Mutual Interfacing Module function using a Remote Analysis function and a GUI(Graphic User Interface). This system consists of a sever and clients. Client performs modeling and preprocessing, and server analyzes the results. The system uses Telnet and FTP based on TCP/IP protocol for connecting a client with a server.. It uses a PC at each work place as a basic platform for design and analysis of goods, and si able to manage a project as a unit. It is shown through an exsample that it is useful as a design tool in the fields.

• Journal of the Korean Institute of Telematics and Electronics
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• v.21 no.6
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• pp.85-93
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• 1984

In the paper, a new constructive initial placement algorithm is proposed in computer aided layout design in LSI. An useful object function are proposed to place the modules in logic design diagram laid down by manual to the fixed chip, reflecting the relative positions between modules and cells, and then an initial placement are determined by the function. In order to show the usefulness of the proposed method, it was compared with clustering development method in maximum cut numbers and total routing lengths by program experiments.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.521-526
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• 2001

This research develops a low-cost and high accurate kinematic calibration method for a parallel typed machining center tool. A planar table is used for a mechanical fixture restricting the platform to place at the constrained pose and a low-cost and high accurate digital indicator is employed for a device checking if the constrained movement is satisfied within the established range. The kinematic parameters calibrated with respect to a single plane aren't influenced from the misalignment of the plane. A parameter observability is successfully obtained even through one planar constraint, which guarantees that the kinematic parameters is estimated by minimizing the cost function.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.219-222
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• 2007

The Full-Off Fitting of Movable Bracket using conventional line have received a dynamic contact impact between contact wire and pantograph of electric rolling stock, so this impact cause a rapid vibration of foreword and back near the supporting point of movable bracket. The Full-Off Fitting on Movable Bracket in conventional line differs from that in high speed line. Now conventional line have required a speed up for new electric locomotive and electric car. In speed-up track and big impact place, the Full-Off Fitting and the dropper often get demage. We have done a study of buffering function to solve that problem in conventional line. We have find a need adopting buffer fitting. It is decrease a dynamic impact between contact wire and pantograph of electric rolling stock.