• Journal of Electrical Engineering and information Science
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• v.1 no.2
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• pp.52-57
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• 1996

Detection of arcing high impedance faults has been a perplexing in the power distribution protection. Transient analysis of distribution disturbances for fault discrimination from other normal events is important for a secure protection of the power system. A simple parameter of wave form distortion quantification is used to analyze the behaviors of arcing faults and normal distribution disturbances. Theoretical perspectives of the transients were studied and actual disturbances were examined. From this investigation, a discrimination guideline based on the revised crest factor is developed. The discrimination method has a high potential to enhance the reliability and security for the distribution system protection.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.5
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• pp.49-58
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• 2013

Appropriate random variables and probability density functions based on statistical analysis should be defined to execute reliability analysis. Most studies have focused on only normal distributions or assumed that the variables showing non-normal characteristics follow the normal distributions. In this study, the reliability problem with non-normal probability distribution was dealt with using the convolution method in the case that the integration domains of variables are limited to a finite range. The results were compared with the traditional method (linear transformation of normal distribution) and Monte Carlo simulation method to verify that the application was in good agreement with the characteristics of probability density functions with peak shapes. However it was observed that the reproducibility was slightly reduced down in the tail parts of density function.

• Steel and Composite Structures
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• v.44 no.5
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• pp.619-632
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• 2022

There are numerous structural details (Longitudinal beam, web plate, U-ribs and I-ribs) in the top and bottom plates of steel box girders, which have significant influences on the longitudinal stress (normal stress) distribution. Clarifying the influence of these structural details on the normal stress distribution is important. In this paper, the ultra-wide steel box girder with large cantilevers of the Jinhai Bridge in China, which is the widest cable-stayed bridge in the world, has been analyzed. A 1:4.5 scale laboratory model of the steel box girder has been manufactured, and the influence of structural details on the normal stress distribution in the top and bottom plates for four different load cases has been analyzed in detail. Furthermore, a three-dimensional finite element model has been established to further investigate the influence regularity of structural details on the normal stress. The experimental and finite element analysis (FEA) results have shown that different structural details of the top and bottom plates have varying effects on the normal stress distribution. Notably, the U-ribs and I-ribs of the top and bottom plates introduce periodicity to the normal stress distribution. The period of the influence of U-ribs on the normal stress distribution is the sum of the single U-rib width and the U-rib spacing, and that of the influence of I-ribs on the normal stress distribution is equal to the spacing of the I-ribs. Furthermore, the same structural details but located at different positions, will have a different effect on the normal stress distribution.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.3
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• pp.738-754
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• 2024

Side-channel analysis (SCA) is a cryptanalytic technique that exploits physical leakages, such as power consumption or electromagnetic emanations, from cryptographic devices to extract secret keys used in cryptographic algorithms. Recent studies have shown that training SCA models with semi-supervised learning can effectively overcome the problem of few labeled power traces. However, the process of training SCA models using semi-supervised learning generates many pseudo-labels. The performance of the SCA model can be reduced by some of these pseudo-labels. To solve this issue, we propose the HWFilter method to improve semi-supervised SCA. This method uses a Hamming Weight Pseudo-label Filter (HWPF) to filter the pseudo-labels generated by the semi-supervised SCA model, which enhances the model's performance. Furthermore, we introduce a normal distribution method for constructing the HWPF. In the normal distribution method, the Hamming weights (HWs) of power traces can be obtained from the normal distribution of power points. These HWs are filtered and combined into a HWPF. The HWFilter was tested using the ASCADv1 database and the AES_HD dataset. The experimental results demonstrate that the HWFilter method can significantly enhance the performance of semi-supervised SCA models. In the ASCADv1 database, the model with HWFilter requires only 33 power traces to recover the key. In the AES_HD dataset, the model with HWFilter outperforms the current best semi-supervised SCA model by 12%.

• Journal of applied mathematics & informatics
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• v.27 no.5_6
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• pp.1429-1433
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• 2009

The likelihood distance for the joint distribution of two multivariate normal distributions with common covariance matrix is explicitly derived. It is useful for identifying outliers which do not follow the joint multivariate normal distribution with common covariance matrix. The likelihood distance derived here is a good ground for the use of a generalized Wilks statistic in influence analysis of two multivariate normal data.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.704-705
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• 2006

Discrete element analysis is used to map various log-normal particle size distributions into measures of the in-sphere pore size distribution. Combinations evaluated range from monosized spheres to include bimodal mixtures and various log-normal distributions. The latter proves most useful in providing a mapping of one distribution into the other (knowing the particle size distribution we want to predict the pore size distribution). Such metrics show predictions where the presence of large pores is anticipated that need to be avoided to ensure high sintered properties.

• Journal of Navigation and Port Research
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• v.42 no.6
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• pp.446-452
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• 2018

A traffic route is an area associated with high risk for accidents due to the flow of heavy traffic. Despite this concern, most studies related to traffic focus solely on traffic distribution. Therefore, there is a need for studies investigating the characteristics of ships' routes and traffic patterns. In this study, an investigation was carried out to analyze the traffic distribution and pattern in 3 major traffic routes for 3 days. For the purpose of the study, based on the prevailing traffic conditions, the route was divided into 10 gate lines. The ships passing through the lines were also classified into either small, medium and large. ND-K-S (normal distribution, kurtosis, and skewness) test was carried out for the traffic distribution at each gate line based on the information analyzed on each traffic route. The analysis of the results obtained from the ND test showed that large vessels have normal distribution, medium sized vessels have satisfied normal distribution in one-way route only while small sized vessels do not have normal distribution. According to the result obtained from the K-S test, normal traffic pattern shows a significant difference between two-way route and one-way route. Results obtained from the K test result shows that in the case of one-way route, vessels have a traffic pattern using a wide range on traffic route. Further analysis shows that vessels concentrate on one side of route in case of two-way route. Results obtained from the S test show that, in case of one-way route, vessels have a normal traffic pattern according to center line. However, analysis pf the results shows that vessels are shifted to the right side of route in case of two-way route. Despite these findings, it should be noted that this study was carried out in only 3 ports, therefore there is need for investigation to be carried out in various routes and conditions in future studies.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.42 no.2
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• pp.18-27
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• 2019

The process control methods based on the statistical analysis apply the analysis method or mathematical model under the assumption that the process characteristic is normally distributed. However, the distribution of data collected by the automatic measurement system in real time is often not followed by normal distribution. As the statistical analysis tools, the process capability index (PCI) has been used a lot as a measure of process capability analysis in the production site. However, PCI has been usually used without checking the normality test for the process data. Even though the normality assumption is violated, if the analysis method under the assumption of the normal distribution is performed, this will be an incorrect result and take a wrong action. When the normality assumption is violated, we can transform the non-normal data into the normal data by using an appropriate normal transformation method. There are various methods of the normal transformation. In this paper, we consider the Box-Cox transformation among them. Hence, the purpose of the study is to expand the analysis method for the multivariate process capability index using Box-Cox transformation. This study proposes the multivariate process capability index to be able to use according to both methodologies whether data is normally distributed or not. Through the computational examples, we compare and discuss the multivariate process capability index between before and after Box-Cox transformation when the process data is not normally distributed.

• Journal of Power System Engineering
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• v.12 no.2
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• pp.41-47
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• 2008

This article deals with the stress analysis of the friction drive, which transmits the power via the rolling resistance on the contract area between the two rotating bodies. On the contact area, friction drives are normally involved with shear stress due to the transmitted force, as well as normal stress. Thus the stress analysis including the shear stress is necessary for the design of the friction drive. Hertzian results can be used to estimate the normal stress distribution and elastic deflection of the contact area, although the shear stress distribution is not well defined. In order to investigate the shear stress distribution and its effects in a friction drive, we have performed the stress analysis of the spherical continuously variable transmission(CVT) using finite element method. The spherical CVT is one of friction drives, which is used in small power applications. The numerical results show that the normal stress distribution is not affected by the transmitted shear force, and the maximal shear stress is increased in small amount along with the shear force.

• Journal of the Korean Ceramic Society
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• v.34 no.9
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• pp.927-934
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• 1997

Static and cyclic fatigue tests were carried out for alumina specimen to study the statistical analyses (normal, lognormal and Weibull distribution) of fatigue lifetime data and nominal initial crack length data. Fatigue lifetime data followed Weibull distribution better than normal or lognormal distribution, for the shape parameter of the notched specimen was larger than that of the unnotched specimen. The nominal initial crack length data obtained from fatigue lifetime followed the lognormal and Weibull distribution better than normal distribution, for the coefficient of variation of the unnotched specimen was larger than that of the notched specimen, and shape parameter of unnotched specimen was smaller than that of the notched specimen.