• Transactions on Electrical and Electronic Materials
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• v.16 no.6
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• pp.312-316
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• 2015

Through silicon via (TSV) technology holds the promise of chip-to-chip or chip-to-package interconnections for higher performance with reduced signal delay and power consumption. It includes high aspect ratio silicon etching, insulation liner deposition, and seamless metal filling. The desired etch profile should be straightforward, but high aspect ratio silicon etching is still a challenge. In this paper, we investigate the use of etch hard mask for finer TSVs etching to have clear definition of etched via pattern. Conventionally employed photoresist methods were initially evaluated as reference processes, and oxide and metal hard mask were investigated. We admit that pure metal mask is rarely employed in industry, but the etch result of metal mask support why hard mask are more realistic for finer TSV etching than conventional photoresist and oxide mask.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.4
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• pp.981-989
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• 1995

A new weight function approach to determine SIF(stress intensity factor) using single-layer potential has been presented. The crack surface displacement field was represented by one boundary integral term whose kernel was modified from Kelvin's fundamental solution. The proposed method enables the calculation of SIF using only one SIF solution without any modification for the crack geometries symmetric in two-dimensional plane such as a center crack in a plate with or without an internal hole, double edge cracks, circumferential crack or radial cracks in a pipe. The application procedure to those crack problems is very simple and straightforward with only one SIF solution. The necessary information in the analysis is two reference SIFs. The analysis results using present closed-form solution were in good agreement with those of the literature.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1997.04a
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• pp.75-84
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• 1997

Based upon the results of numerical calculation. empirical scaling equations were made for supersonic under-expanded jets in both axisymmetric and two dimensional flows. The objective of the present study is to obtain a straightforward method that can predict the under-expanded supersonic jets issuing from various kinds of nozzles. The present empirical equations were agreed with the calculation results of total variation diminishing difference scheme. The supersonic under-expanded jets operating with a given pressure ratio could be well predicted by the present scaling equations.

• Proceedings of the Society of Korea Industrial and System Engineering Conference
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• 2002.05a
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• pp.371-377
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• 2002

In this paper, We consider some generalization of these five basic indices to cover non-normal distribution. The proposed generalizations are compared with the five basic indices. The results show that the proposed generalizations are more accurate than those basic indices and other generalization in measuring process capability. We compared an estimation methods by Clements with based on sample percentiles, WVM to calculate the proposed generalization as an example. The results indicated that Clements method is more accurate than percentile method, WVM in measuring process capability. But the calculations of percentile method are easy to understand, straightforward to apply, and show be valuable used for applications.

• 한국전산유체공학회:학술대회논문집
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• 2009.11a
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• pp.218-222
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• 2009

A level-set (LS) method is presented for computation of boiling phenomena which involve liquid-vapor interfaces that evolve, merge and break up in time, the flow and temperature fields influenced by the interfacial motion, and the microlayer that forms between the solid and the vapor phase near the wall. The LS formulation for tracking the phase interfaces is modified to include the effects of phase change on the liquid-vapor interface and contact angle on the liquid-vapor-solid interline. The LS method can calculate an interface curvature accurately by using a smooth distance function. Also, it is straightforward to implement for two-phase flows in complex geometries. The numerical method is applied for analysis of nucleate boiling on a horizontal surface and film boiling on a horizontal cylinder.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.5
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• pp.257-262
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• 2003

The voltage unbalance factor derived from symmetrical component analysis requires manipulation of complex quantities. To facilitate the calculation of the voltage unbalance factor in field applications, this paper proposes the method for calculating the voltage unbalance factor in terms of the line voltage magnitudes that are readily available in moat practical circumstances. It is shown that the line voltages appear as circular Phasor loci for given voltage unbalance factor, and a graphical chart is developed that can be used to determine the voltage unbalance factor in a straightforward manner avoiding calculation.

• Journal of the Korean Statistical Society
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• v.35 no.4
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• pp.419-439
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• 2006

The article develops a new class of distributions by introducing a nonnegative perturbing function to $t_\nu$ distribution having location and scale parameters. The class is obtained by using transformations and conditioning. The class strictly includes $t_\nu$ and $skew-t_\nu$ distributions. It provides yet other models useful for selection modeling and robustness analysis. Analytic forms of the densities are obtained and distributional properties are studied. These developments are followed by an easy method for estimating the distribution by using Markov chain Monte Carlo. It is shown that the method is straightforward to specify distribution ally and to implement computationally, with output readily adopted for constructing required criterion. The method is illustrated by using a simulation study.

• ETRI Journal
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• v.36 no.3
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• pp.469-478
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• 2014

RSA signature algorithms using the Chinese remainder theorem (CRT-RSA) are approximately four-times faster than straightforward implementations of an RSA cryptosystem. However, the CRT-RSA is known to be vulnerable to fault attacks; even one execution of the algorithm is sufficient to reveal the secret keys. Over the past few years, several countermeasures against CRT-RSA fault attacks have tended to involve additional exponentiations or inversions, and in most cases, they are also vulnerable to new variants of fault attacks. In this paper, we review how Shamir's countermeasure can be broken by fault attacks and improve the countermeasure to prevent future fault attacks, with the added benefit of low additional costs. In our experiment, we use the side-channel analysis resistance framework system, a fault injection testing and verification system, which enables us to inject a fault into the right position, even to within $1{\mu}s$. We also explain how to find the exact timing of the target operation using an Atmega128 software board.

• Journal of applied mathematics & informatics
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• v.8 no.1
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• pp.243-252
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• 2001

The points of failure of a decomposition process are defined to be the union of the points of failure from two component point processes for software reliability systems. Because sampling from the likelihood function of the decomposition model is difficulty, Gibbs Sampler can be applied in a straightforward manner. A Markov Chain Monte Carlo method with data augmentation is developed to compute the features of the posterior distribution. For model determination, we explored the prequential conditional predictive ordinate criterion that selects the best model with the largest posterior likelihood among models using all possible subsets of the component intensity functions. A numerical example with a simulated data set is given.

• Journal of applied mathematics & informatics
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• v.26 no.1_2
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• pp.235-249
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• 2008

On-demand routing protocol in ad hoc network is that establishes a route to a destination node only when it is required by a source node. But, it is necessary to reestablish a new route when an active route breaks down. The reconstruction process establishes another route by flooding messages from the source to the destination, cause not only heavy traffic but also long delays in route discovery. A good method for analyzing performance of protocols is important for deriving better systems. In this paper, we suggest the numerical formulas of a representative on-demand routing protocol AODV, ARMP, and RRAODV to estimate the performance of these routing protocols for analyzing the performance of these protocols. The proposed analytical models are very simple and straightforward. The results of analysis show good agreement with the results of computer simulations.