• Journal of Biomedical Engineering Research
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• v.16 no.3
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• pp.279-288
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• 1995

Ultrasonic Doppler systems for the purpose of estimating blood flow velocity, blood flow volume, and flow imaging are commonly used due to advantages of non-invasive and real time observation. Specially, the technical developments of color flow mapping (2-D Doppler) systems have made a relatively rapid progress. However, the 2-D Doppler systems have several problems, such as the range ambiguity, low signal to noise ratio, and slow frame rate. The slow frame rate problem is resolved by using the spatial average which is a method to acquire more data samples for mean frequency estimation. In this paper, spatial average method using the 2nd order sampling instead of quadrature sampling is proposed. The experimental results show that the proposed methods have good performance and easy application to the color flow mapping system.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.3
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• pp.293-300
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• 2007

The aim of this paper is to design a speed controller of a DC motor by selection of a PID parameters using genetic algorithm. The model of a DC motor is considered as a typical non-oscillatory, second-order system, And this paper compares three kinds of tuning methods of parameter for PID controller. One is the controller design by the genetic algorithm. second is the controller design by the model matching method third is the controller design by Ziegler and Nichols method. It was found that the proposed PID parameters adjustment by the genetic algorithm is better than the Ziegler & Nickels' method. And also found that the results of the method by the genetic algorithm is nearly same as the model matching method which is analytical method. The proposed method could be applied to the higher order system which is not easy to use the model matching method.

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.763-768
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• 1994

A hierarchical Petri- net is utilized in supervising an automated vehicle system, The supervisory system is supported by computer networking in order to facilitate necessary processing, and consists of control flow level and computer allocation level so that a designer and an operator can easily build and/or access to each level. There are two modes of utilizing Petri net here in this paper. One is to employ it in designing the control system, in order to optimally allocate computers in every stage of processing. The other is for supervision of the system in operation, in order for the operator to be in a easy-to-comprehend environment of operation. The effect of these two modes of utilizing Petri net is examined.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.2 no.3
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• pp.174-178
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• 2002

This paper discusses a blind equalization technique for FIR channel system, that might be minimum phase or not, in digital communication. The proposed techniques consist of two parts. One is to estimate the original channel coefficients based on fourth-order cumulants of the channel output, the other is to employ RBF neural network to model an inverse system fur the original channel. Here, the estimated channel is used as a reference system to train the RBF. The proposed RBF equalizer provides fast and easy teaming, due to the structural efficiency and excellent recognition-capability of R3F neural network. Throughout the simulation studies, it was found that the proposed blind RBF equalizer performed favorably better than the blind MLP equalizer, while requiring the relatively smaller computation steps in tranining.

• Smart Media Journal
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• v.9 no.2
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• pp.33-38
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• 2020

Order preserving matching refers to the problem of reporting substrings of a given text where there exists order isomorphism with the pattern. In this paper, we propose a new algorithm based on filtering and evaluation. The proposed algorithm is simple and easy to implement, and runs in linear time on average. Experimental results show that it works efficiently with real world data.

• Journal of electromagnetic engineering and science
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• v.9 no.1
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• pp.1-6
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• 2009

An effective method is proposed to suppress the second-order beams(SOBs) that result from the cross-polarized fields of 2D edge slot arrays. By rearranging the conventional sequence of stacking waveguides, the SOBs are shown to be considerably reduced and the 9 dB suppression is obtained. The optimal sequence is obtained from the genetic and exhaustive searches and its effects are verified using near-field measurements as well as theoretical estimation. Since the proposed method requires no additional polarizing structures such as baffles, it is very easy and cost-effective to implement.

• ETRI Journal
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• v.32 no.3
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• pp.472-474
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• 2010

In this letter, a novel zeroth-order resonant (ZOR) antenna on vialess co-planar waveguide (CPW) is proposed. It is based on a composite right/left-handed CPW transmission line. To achieve a compact size, this antenna utilizes the ZOR condition, and its reactive parameters determine the resonant frequency. Each unit cell is composed of a metallic top patch and meander lines. Since it is realized on the CPW single layer, the proposed antenna has the benefits of being a compact size and easy to fabricate. The bandwidth of 6.8% and efficiency of 62% are experimentally achieved. Its bandwidth is enhanced compared with other ZOR antennas.

• Proceedings of the Acoustical Society of Korea Conference
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• 1994.06a
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• pp.770-774
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• 1994

The volume of an acoustic source is important in determining various acoustic parameters. One of the suggested techniques is the internal pressure method incorporating a loudspeaker attached to a chamber wall and a microphone inserted into the cavity. Although the method is easy to handle with a very simple measurement setup, the coupling effects between the dynamic system of the loudspeaker and acoustic field, and the effects of higher order modes introduced by the discontinuities in the acoustic field, and the effects of higher order modes introduced by the discontinuities in the acoustic field should be considered for precise result. In this study, higher order modes due to the discontinuities of loudspeaker and microphone boundaries are included and the electro-acoustic coupling effects are compensated for by using the results of two cylinders with different lengths. The volume velocity of a loudspeaker thus obtained agrees very with that measured by laser sensor.

• Archives of design research
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• v.19 no.2 s.64
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• pp.43-52
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• 2006

The most important issue the online shopping mall for clothes is facing in the rapid growth of the online shopping mali is the high rate of the return of the goods alter purchase. The high rate of the return leads to the dissatisfaction md lack of trust from the consumers in the online shopping mall for clothes, which in turn leads to the bleak prospect for the online shopping mall for clothes as a result of the consumers' dissatisfaction. Although a type of online shopping mall using the cyber-fitting technology has emerged recently, it has succeeded only in provoking a visual interest, for it is also not satisfying the demand of the consumers by falling short in providing information. Thus, this research seeks for the resolutions of the problems related to the user-oriented online shopping. First of the resolutions is the development of a new prototype which the consumers can easily access; second is the visualization of the information using the 3D virtual-reality of he prototype through interface, which will help the consumers to make more accurate judgments. In other words, this study seeks to provide a type of prototype of an online shopping mall that meets the demand of the consumers using the 3D avatars, unlike the unilateral and conventional malls out there.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.35 no.10
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• pp.427-437
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• 1986

Identification of the plants is not easy task especially in the fields of process control. From this point of view, Kitamori developed a method of control system design based on partial knowledge about controlled processes. However, it is difficult to control the oscillatory plant by kitamori's method. In this paper, we develope a method of partial model matching control system design, which have desirable pole-placements in order to improve the above defects. Design examples are given to illustrate the effectiveness of the method.