• International Journal of Internet, Broadcasting and Communication
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• 제12권1호
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• pp.111-115
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• 2020

In this paper, I proposed an effective technique for accurately predicting pixel values using edge components. Adjacent pixel values are similar to each other. That is, generally, similarity exists between adjacent pixels in an image. In the proposed algorithm, edge components are detected using the surrounding pixels in the first step, and pixel values are estimated using the edge components in the second step. Therefore, the prediction accuracy of the pixel value is improved and the prediction error is reduced. Pixel value prediction is a necessary technique for various applications such as image magnification and confidential data concealment. Experimental results show that the proposed method has higher prediction accuracy and fewer prediction error. Therefore, the proposed technique can be effectively used for applications such as image magnification and confidential data concealment.

• Journal of Advanced Marine Engineering and Technology
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• 제27권5호
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• pp.581-588
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• 2003

Heat transfer characteristics of a pair of longitudinal vortices using a transient liquid crystal technique are studied experimentally. In order to control the strength of longitudinal vortices, angle of attack of the vortex generators is $20^{\circ}$and the length of space from the centerline the vortex generations is 25mm apart. The heat transfer measurements using a transfer coefficients. The following conclusions are obtained from the present experiment. When any vortex generators are not set up in wind tunnel test, heat transfer rate is low respectively. However, with the vortex generators of rectangular winglet, the heat transfer on the local surface can be enhanced.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2004년도 추계학술대회 논문집
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• pp.34-35
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• 2004

Three dimensional density distributions of impinging and eccentric flames have been investigated by digital speckle tomography. The flames have been ignited by a mixture of butane and air from a circular nozzle and impinged against a plate located at the upper side of the burner exit. For comparison with experimental data, computer synthesized phantoms of impinging and eccentric flames have been reconstructed by a developed three-dimensional multiplicative algebraic reconstruction technique (MART). The advanced reconstruction in the stagnation flow region involved the sharp change of the flow direction and pressure gradient has been developed using a cross-correlation method and new scanning technique for the speckle displacement.

• International Journal of Advanced Culture Technology
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• 제5권3호
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• pp.40-45
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• 2017

This data mining technique was used to extract useful information from percutaneous coronary intervention data obtained from the US public data homepage. The experiment was performed by extracting data on the area, frequency of operation, and the number of deaths. It led us to finding of meaningful correlations, patterns, and trends using various algorithms, pattern techniques, and statistical techniques. In this paper, information is obtained through efficient decision tree and cluster analysis in predicting the incidence of percutaneous coronary intervention and mortality. In the cluster analysis, EM algorithm was used to evaluate the suitability of the algorithm for each situation based on performance tests and verification of results. In the cluster analysis, the experimental data were classified using the EM algorithm, and we evaluated which models are more effective in comparing functions. Using data mining technique, it was identified which areas had effective treatment techniques and which areas were vulnerable, and we can predict the frequency and mortality of percutaneous coronary intervention for heart disease.

• 한국멀티미디어학회논문지
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• 제18권7호
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• pp.793-805
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• 2015

Nowadays the amount of data obtained from advanced weather radars is growing to provide higher spatio-temporal resolution. Accordingly radar data compression is important to use limited network bandwidth and storage effectively. In this paper, we proposed a hierarchical compression method for weather radar data having high spatio-temporal resolution. The method is applied to radar reflectivity and evaluated in aspects of accuracy of quantitative rainfall intensity. The technique provides three compression levels from only 1 compressed stream for three radar user groups-signal processor, quality controller, weather analyst. Experimental results show that the method has maximum 13% and minimum 33% of compression rates, and outperforms 25% higher than general compression technique such as gzip.

• Journal of Advanced Marine Engineering and Technology
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• 제24권5호
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• pp.33-41
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• 2000

Three dimensional flow fields around passenger car body was computed by PAM-FLOW, well-known and validated computer program for thermal and fluid analysis. Regarding the computational method, a Navier-Stokes solver based on finite element method with various turbulent models and adaptive grid technique (H-refinement)was adopted. The results were physically reasonable and compared with experimental data, giving good agreement. It was found that three dimensional flow simulation with H-refinement technique had potential for prediction of low fie이 around vehicle and the ability to predict vortex in the wake, which is vital for CFD to be used for automobile aerodynamic calculation.

• 한국정밀공학회지
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• 제19권1호
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• pp.219-226
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• 2002

The mechanical etching technique has recently been developed to a powder blasting technique for various materials, capable of producing micro structures larger than 100$\mu$ m. This paper describes the performance of powder blasting technique in micro-pocketing of stainless steel and the effect of the number of nozzle scanning and the nozzle height on the depth and width of pockets. Experimental results showed that increasing the no. of nozzle scanning and decreasing the nozzle height resulted in the increase of depth and width in pockets. Increase of width results from wear of mask film.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2005년도 추계종합학술대회
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• pp.383-386
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• 2005

This study proposes a case based reasoning system with two dimensional reduction techniques. In this study, vertical and horizontal dimensions of the research data are reduced through hybrid feature and instance selection process using genetic algorithms. We applied the proposed model to customer classification model which utilizes customers' demographic characteristics as inputs to predict their buying behavior for the specific product. Experimental results show that the proposed technique may improve the classification accuracy and outperform various optimized models of typical CBR system.

• Steel and Composite Structures
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• 제23권2호
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• pp.161-172
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• 2017

A new composite tube connection method called the pre-tightened teeth connection technique is proposed to improve the composite tube connection efficiency. This paper first introduces the manufacturing process of the proposed technique. It then outlines how the mechanical properties of this technology were tested using four test groups. The factors that influence the load-bearing capacity and damage model of the connection were analyzed, and finally, the transfer load mechanism was investigated. The following conclusions can be obtained from the research results. (1) The new technique improves the compressive connection efficiency by a maximum of 79%, with the efficiency exceeding that of adhesive connections of the same thickness. (2) Changing the depth of teeth results in two types of damage: local compressive damage and shear damage. The bearing capacity can be improved by increasing the depth, length, and number of teeth as well as the pre-tightening force. (3) The capacity of the technique to transfer high loads is a result of both the relatively high interlaminar shear strength of the pultruded composite and the interlaminar shear strength increase provided by the pre-tightening force. The proposed technique shows favorable mechanical properties, and therefore, it can be extensively applied in the engineering field.

• The Journal of the Acoustical Society of Korea
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• 제23권2E호
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• pp.56-67
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• 2004

Despite abundant research outcomes of blind source separation (BSS) in many types of simulated environments, their performances are still not satisfactory to be applied to the real environments. The major obstacle may seem the finite filter length of the assumed mixing model and the nonlinear sensor noises. This paper presents a two-step speech enhancement method with multiple microphone inputs. The first step performs a frequency-domain BSS algorithm to produce multiple outputs without any prior knowledge of the mixed source signals. The second step further removes the remaining cross-channel interference by a spectral cancellation approach using a probabilistic source absence/presence detection technique. The desired primary source is detected every frame of the signal, and the secondary source is estimated in the power spectral domain using the other BSS output as a reference interfering source. Then the estimated secondary source is subtracted to reduce the cross-channel interference. Our experimental results show good separation enhancement performances on the real recordings of speech and music signals compared to the conventional BSS methods.