• Journal of Industrial Technology
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• v.21 no.B
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• pp.163-174
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• 2001

A dynamic reliability model for analyzing the stability of armor units on rubble-mound breakwater is mathematically developed by using Hudson's formula and definition of single-failure mode. The probability density functions of resistance and loading functions are defined properly, the related parameters to those probability density functions are also estimated straightforwardly by the first-order analysis. It is found that probabilities of failure for the stability of armor units on rubble-mound breakwater are continuously increased as the service periods are elapsed, because of the occurrence of repeated loading of random magnitude by which the resistance may be deteriorated. In particular, the factor of safety is incorporated into the dynamic reliability model in order to evaluate the probability of failure as a function of factor of safety. It may thus be possible to take some informations for optimal design as well as managements and repairs of armor units on rubble-mound breakwater from the dynamic reliability analyses.

• Journal of Korean Society for Quality Management
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• v.26 no.4
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• pp.250-264
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• 1998

The purpose of the thesis is to develop simulation program for forecasting of optical connector. So we can achieve the time and the money saving for making the optical connector. Optical performance (insertion loss) of optical connector mainly relies on 3 misalignment factors-ferrule factor due to mis-manufacture from design, auto-centering effect that is fiber behavior phenomena between hole and fiber, fiber misalignment factor. Simulation use experimental data with auto-centering effect and fiber factor and use pseudo data with ferrule through random number generation because it is developing stage. In this study we a, pp.y kernel density estimation method with experimental data in order to know whether it belong to or not specific parametric distribution family. And we simulate to forecast insertion loss of optical multifiber connector under specific design model using nonparametric bootstrap resampling data and parametric pseudo samples from uniform distribution. We obtain the tolerance specifications of misalignment factors satisfying not exceed in maximum 1.0dB and choose optimal hole diameter.

• Proceedings of the KIEE Conference
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• 1999.11c
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• pp.781-783
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• 1999

A storage or transmission of image is difficult without image compression processing because the numbers of generated or reborned image data are very much. In case of the random signal, image compression efficiency is low doing without loss of image information, but compressibility by using JPEG is better. We used Huffman code of JPEG, it assigne the low bit value for data of a lot of generated frequency, assigne the high bit value for data of a small quantity. This paper improved image compression efficiency with transformming Q-factor and certified the results with compressed image. A proposed method is very efficience for continuos a color tone image.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.8
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• pp.390-398
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• 2000

Leakage impulse current of the contaminated insulators by using experiment data were studied. The impulse current in phase-time relationship was analyzed on line post insulators. Also, frequency components and crest factor of the leakage current were investigated to provide a scheme for an early detection of insulator incipient failure. The study shows that the phase-time characteristic is non-stationary and random and, non-harmonic component and crest factor can be promising parameters for detecting insulator leakage currents.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.3
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• pp.451-456
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• 2004

This present experimental study has dealt with the heat transfer characteristics of plastic particle slurry which flows in a circular tube. This type of slurry is suggested for heat transfer enhancement effect cause by random and vortex effect of plastic particle dispersed in water. As a result, the thermal boundary layer becomes thin so the heat transfer coefficient on the tube wall more increase compare to pure water flow. This experimental test section was composed with stainless pipe which has the length of 2000mm, inner pipe diameter of 14mm and outer pipe diameter of 60mm. The most effective and important parameter of this experiment is plastic packing factor(PPF). The focuses of these results are pressure drop and heat transfer coefficient. As results, the friction factor of plastic particle slurry becomes higher at laminar flow region than pure water because of buoyancy effect of plastic particle but the local heat transfer coefficient becomes higher.

• Journal of KSNVE
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• v.8 no.4
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• pp.706-714
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• 1998

The purpose of this study is to analyse the main factors and attributes of psychological evaluation to noise. For this purpose, a psycho-acustic experiment was conducted by using the method of rating scale. 52 subjects were participated in the experiment, 20 stimuli were presented to subjects in random order with 23 adjectives. As a result of factor analysis, it was found that the primary factors for evaluating the quality of noise subjectively are four factors of unpleasantness, intensity, irregularity, and sharpness. And, as a result of MDPREF(multi-dimensional analysis of preference data), it was found that the noise sources including the factors of unpleasantness, intensity, and irregularity are related to the sounds of hammering in construction field, car horn, road traffic, idling of car, and printing by computer printer, and the factor of sharpness are the sounds of car siren, claps of thunder, car horn, and snowstorm etc.

• Journal of applied mathematics & informatics
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• v.6 no.1
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• pp.31-50
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• 1999

We revisit the problems of testing three-factor classifica-tion models with a single observation per cell. A common approach in analyzing such nonreplicated data is to omit the highest order in-teraction and regard it as error. This paper discusses the use of a multiplicative model(See and Smith 1996 and 1998) which is applied on residuals in order to separate the variablility due to three-factor interaction from what is counted as random error. in particualr to test the significance of the interaction term we derived an approxi-mated distribution of the likelihood ratio test statistic based on the quadrilinear model known as Tucher's three-mode principal compo-nent model. The derivation utilizes the distribution of the eignevalues of the Wishart matrix.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.814-820
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• 2000

This papers investigates the combined effects of parameters such as die surface finish, die directionality of stoning, contact pressure and draw speed on the resulting friction factor. Also, this study show the correlation between the NN(Neural Network) and DOE (Design of Experiments) to reduce the number of experiments without the loss of the effects of parameter upon friction factor. The experiments were run in random order with at least three replicates. It was found that the directional stoning orthogonal to the pulling direction is lower friction than directional stoning parallel to the pulling direction using FCD55 die and SPCEN

• The Korean Journal of Food And Nutrition
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• v.27 no.3
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• pp.393-399
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• 2014

The purpose of this study is to analyze the LOHAS tendency of new seniors' and its effects on the attitude and purchase intention for environmental-friendly food materials. Data were collected through a questionnaire survey from random sample of 162 senior customers in Seoul and Kyunggi area. The LOHAS tendency of new seniors can be divided into three factors; environmental-friendly, sustainability and sociality. Environmental problems affected the environmental-friendly factor the most while manufacturing techniques for sustainable products and recycling habits were key variables for the sustainability factor. The idea of companies sharing their value system of LOHAS tendency was the most significant for the sociality factor. Each of these LOHAS tendency factors influenced the purchase intention of the new seniors.

• Journal of the Semiconductor & Display Technology
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• v.18 no.3
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• pp.1-6
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• 2019

Foreground/background segmentation in video sequences is often one of the first tasks in machine vision applications, making it a critical part of the system. In this paper, we present an improved sample-based technique that provides robust background image as well as segmentation mask. The conventional multiple interval sampling (MIS) algorithm have suffer from the unbalance of computation time per frame and the rapid change of confidence factor of background pixel. To balance the computation amount, a random-based pixel update scheme is proposed and a spatial and temporal smoothing technique is adopted to increase reliability of the confidence factor. The proposed method allows the sampling queue to have more dispersed data in time and space, and provides more continuous and reliable confidence factor. Experimental results revealed that our method works well to estimate stable background image and the foreground mask.