• 한국세라믹학회지
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• 제30권6호
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• pp.469-477
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• 1993

Residual stresses is one of the major factors to degrade the magnetic properties of VCR magnetic heads. Vicker's indentation technique was adapted to estimate the residual stresses Residual stresses and distribution in the glass and ferrite were obtained after bonding ferrite with glass, varing the cooling rate. The compressive and tensile stresses were developed in the interface and gradually decreased with increasing distance from the interface. The stresses were decreased with a cooling rate. The mean values of residual stress in ferrite were 10MN/㎡, 8MN/㎡, 5MN/㎡ with cooling rate 10℃/min, 5℃/min, 1℃/min respectively. When the bonded sample was annealed above the glass transition temperature followed by cooling at 5℃/min cooling rate, the residual stress was reduced to 6MN/㎡.

• 한국세라믹학회지
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• 제31권12호
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• pp.1449-1458
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• 1994

A new analytical model which can discribe the relationship between the bridging stress and the crack opening displacement was proposed to investigate the microstructural effect on the R-curve behavior in a polycrystalline alumina. The crack opening displacement according to the distance behind the stationary crack tip was measured using in-situ fracture technique in an SEM, and then used for a fitting procedure to obtain the distribution of bridging stress. The current model and an empirical power law relation were introduced into the fitting procedure. The results indicated that the bridging stress function and R-curve computed by the current model were consistent with those computed by the power law relation. The microstructural factor, e.g., the distribution of grain size, was also found to be closely related to the bridging stress. Thus, this model explained well the interaction effect between the distribution of bridging stress and the local-fracture-controlling microstructure, providing important information for the systematic interpretation of microfracture mechanism including R-curve behavior of a monolithic alumina.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.59-62
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• 2008

This paper presents the procedure and the results of modal identification testing of a seismic monitoring system central processing unit cabinet for a nuclear power plant. This paper also provides a model updating for making effective analytical modeling of cabinet-type electrical equipment by comparing the test results with the analysis results. From the test results and their interpretation, modal properties (modal frequency, mode shape, and modal damping) of the specimen were satisfactorily identified. However, the analysis results may need to study further to find the effective and presentative model for the cabinet-type electrical equipment. This paper just presents the first stage of the research project "Development of dynamic behavior analysis technique of dynamic structure system" which is trying to build the lumped mass beam stick model even their results do not agree well with the test results.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.134.1-134
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• 2001

The paper presents a sonar based map building method. The environment is a room or area inside a building, which is composed of four types of geometric primitives(corners, edges, cylinders, and walls). We also assume the environment can be modeled into two dimensional map in terms of planes(walls), points(corner and edge), and circle(cylinder). In a real world where most of the object surfaces are specular ones, a sonar sensor suffers from a multipath effect which results in a wrong interpretation of the location of an object. To reduce the effect and uncertainty, the method employs a simple thresholding technique for extracting circular arc features called regions of constant depth(RCD) from scanning sonar data. The usefulness of the approach is illustrated with the results produced by sets of experiments.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.18-21
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• 2008

Lee (2008) proposed the pansharpening method to reconstruct at the higher resolution the multispectral images which agree with the spectral values observed from the sensor of the lower resolution values. It outperformed over several current techniques for the statistical analysis with quantitative measures, and generated the imagery of good quality for visual interpretation. However, if a small object stretches over two adjacent pixels with different spectral characteristics at the lower resolution, the pixels of the object at the higher resolution may have different multispectral values according to their location even though they have a same intensity in the panchromatic image of higher resolution. To correct this problem, this study employed an iterative technique similar to the image restoration scheme of Point-Jacobian iterative MAP estimation. The effect of pansharpening on image segmentation/classification was assessed for various techniques. The method was applied to the IKONOS image acquired over the area around Anyang City of Korea.

• 한국전기전자재료학회논문지
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• 제17권5호
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• pp.567-571
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• 2004

Recently, GIS(Gas Insulated Switchgear) has been recognizing of importance on development of diagnosis technique which is happened problem on confidence for a long time use. Therefore, the measurement and analysis of PD with prior phenomenon of insulation breakdown is used many method of diagnosis for GIS. In this paper, we simulate trouble condition in DS and analysis trouble signal to use electrical and mechanical methods, interpretation of detected signal has analysed with to use ø-q-n pattern and neural network. For this analysis, we have used the induction and AE(acoustic emission) sensors. For the simulation experiment, we make DS for 170 KV GIS and analyze the classification and characteristics of detected signals with the application of neural network algorithm.

• Communications for Statistical Applications and Methods
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• 제2권2호
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• pp.176-183
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• 1995

Mean opinion score (MOS) method has been used in many areas to quantify opinions of respondents not only in survey research but in evaluating the parameters of population that are not measurable of are technically hard to be measured. Histogram is an important graphical technique because of the role it plays in describing categorical data as well as quantitative. In MOS method, subjective opinions of respondents are quantified by opinion scores and the arithmetic means of opinion scores have been used to describe the interesting population. Since opinion scores are polytomous, the values of arithmetic means have little meanings. In this paper, cumulative percentage curves as a function of the means of opinion scores are derived by combining means of opinion scores and histograms. It is proposed for better interpretation to opinion scores in MOS method, one of subjective evaluation methods.

• 지역연구
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• 제14권2호
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• pp.35-50
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• 1998

This paper examines the determinants of imbalanced regional development in Korea during the period of 1985-1995. The review of previous analytical techniques have been used to analyze the determinants of disparities in regional development of disparities in regional development, but few has applied the regression technique which reduces a bias due to heterogeneity across region. The results of the study show that Kmenta model with per capita GRDP as dependent variable can reduce the heterogeneity bias in regional development and can minimize the statical errors in estimation and interpretation of the coefficients of the explanatory variables. According to the results of Kmenta model, urban infrastructure such as roads, information and communication facilities are major causes of regional disparity over the period of 1985-1995. The results of the study also indicate that local government should devote their policy efforts to identify and utilize the unique soci-economic characteristics of each locality in the process of regional development.

• International Journal of Aeronautical and Space Sciences
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• 제12권4호
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• pp.396-402
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• 2011

Aircraft combat survivability is an essential factor in the design of combat aircrafts that operate in an enemy air defense area. The combat aircrafts will be confronted with anti-aircraft artillery and/or surface-to-air missiles (SAM) from the ground, and their survivability can be divided into two categories: susceptibility and vulnerability. This article studies the prediction of susceptibility in the case of a one-on-one engagement between the combat aircraft and a surface-based threat. The weighted score method is suggested for the prediction of susceptibility parameters, and Monte Carlo simulations are carried out to draw qualitative interpretation of the susceptibility characteristics of combat aircraft systems, such as the F-16 C/D, and the hypersonic aircraft, which is under development in the United States, versus ground threat from the SAM SA-10.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2009년도 춘계학술발표회 논문집
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• pp.151-156
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• 2009

Forward modelling of ground penetrating radar (GPR) data is implemented using a new finite element ray tracing technique. The method is different from conventional ray tracing techniques in that the radar cross section of buried targets, the effective area of the receiving antenna, and the attenuation along the raypath are computed. The forward models are used to understand radar signatures measured across various ground structures which are important in detecting engineering hazards at construction sites, void spaces beneath simulated road beds, as well as a learning tool to avoid pitfalls in radargram interpretation. Forward modelling of radar data also can be used in predicting possible structures present at cultural property sites.