• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권2호
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• pp.1100-1123
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• 2019

A code-based cryptosystem can resist quantum-computing attacks. However, an original system based on the Goppa code has a large key size, which makes it unpractical in embedded devices with limited sources. Many special error-correcting codes have recently been developed to reduce the key size, and yet these systems are easily broken through side channel attacks, particularly differential power analysis (DPA) attacks, when they are applied to hardware devices. To address this problem, a higher-order masking scheme for a McEliece cryptosystem based on the quasi-dyadic moderate density parity check (QD-MDPC) code has been proposed. The proposed scheme has a small key size and is able to resist DPA attacks. In this paper, a novel McEliece cryptosystem based on the QD-MDPC code is demonstrated. The key size of this novel cryptosystem is reduced by 78 times, which meets the requirements of embedded devices. Further, based on the novel cryptosystem, a higher-order masking scheme was developed by constructing an extension Ishai-Sahai-Wagne (ISW) masking scheme. The authenticity and integrity analysis verify that the proposed scheme has higher security than conventional approaches. Finally, a side channel attack experiment was also conducted to verify that the novel masking system is able to defend against high-order DPA attacks on hardware devices. Based on the experimental validation, it can be concluded that the proposed higher-order masking scheme can be applied as an advanced protection solution for devices with limited resources.

• Communications for Statistical Applications and Methods
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• 제26권6호
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• pp.527-538
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• 2019

This paper considers the issue of obtaining the optimal design in Poisson regression model when the sample size is small. Poisson regression model is widely used for the analysis of count data. Asymptotic theory provides the basis for making inference on the parameters in this model. However, for small size experiments, asymptotic approximations, such as unbiasedness, may not be valid. Therefore, first, we employ the second order expansion of the bias of the maximum likelihood estimator (MLE) and derive the mean square error (MSE) of MLE to measure the quality of an estimator. We then define DM-optimality criterion, which is based on a function of the MSE. This criterion is applied to obtain locally optimal designs for small size experiments. The effect of sample size on the obtained designs are shown. We also obtain locally DM-optimal designs for some special cases of the model.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2001년도 춘계학술대회 논문집
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• pp.205-208
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• 2001

Localized shear band is investigated through the analysis of one-dimensional model for simple shearing deformation of thermally rate dependent material. Generally mesh size or interval of nodes play an important role in determining the overall flow behavior of the material. In order to observe these size effects we adapted non-local theory by including higher order strain gradients of the equivalent strain into the constitutive equation for the flow stress. for the ease of convergence and numerical stability the inplicit finite difference scheme is employed.

• 대한산업공학회지
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• 제23권2호
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• pp.421-432
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• 1997

In general, Automated Storage/Retrieval Systems (AS/RS) have racks of equal size. But higher utilization of warehouse storage can be achieved by using AS/RS with racks of different size. Therefore those systems are adequate and efficient in current environment. In this paper, travel time models are developed for AS/RS with racks of different size under randomized storage in each zone. Each zone has its own rack size. In order to confirm the proposed travel time models, some numerical examples are given.

• 한국콘텐츠학회논문지
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• 제9권12호
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• pp.537-545
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• 2009

본 논문에서는 이동통신망을 위한 효율적인 멀티캐스트 인과순서 알고리즘과 채널전환 프로토콜을 제안하였다. 메시지 전달 순서를 유지하기 위한 제어정보의 크기는 이동통신망에서의 채널전환과 메시지 전송성능에 큰 영향을 주므로 제어정보의 크기를 최소화할 필요가 있다. 이를 위해 모든 유효한 통신패턴을 분석하여 인과순서를 유지하는데 필수적이지 않은 중복정보를 가능한 이른 시기에 찾아내어 제거하고, 전송되는 제어정보를 최소화하는 채널전환 프로토콜을 사용하였다. 시뮬레이션을 통해 제안한 알고리즘이 기존의 알고리즘보다 더 좋은 성능을 보임을 보였다.

• 대한수학회보
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• 제52권1호
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• pp.287-299
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• 2015

A theta graph is the union of three internally disjoint paths that have the same two distinct end vertices. We show that every graph of order $n{\geq}12$ and size at least ${\lfloor}\frac{11n-18}{2}{\rfloor}$ contains three disjoint theta graphs. As a corollary, every graph of order $n{\geq}12$ and size at least ${\lfloor}\frac{11n-18}{2}{\rfloor}$ contains three disjoint cycles of even length.

• 대한인간공학회지
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• 제33권6호
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• pp.499-513
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• 2014

Objective: The objective of this study was to examine frame ratio of text information and font size in the circle smartwatch. Background: Recently, electronic manufacturers try to develop the original metaphor of traditional wrist watch (circle) in terms of smartwatch. They endeavor to break the square display in order to improve emotional customer satisfaction. Method: The experiments examined twenty level of text information design, combinations of four frame ratios (1:1, 4:3, 16:9, 21:9) and five font sizes (6pt, 7pt, 8pt, 9pt, 10pt). Nineteen participants volunteered for the experiment. Dependent variables were WPM (Words per Minute), reading preference, design preference and total preference. Furthermore, small circle display was made by using circle display data (1.3inch), which was exhibited in IFA (International Funkausstellung) 2014. Results: As a result, ANOVA (Analysis of Variance) revealed that WPM, and task time preference affect the specific frame ratio and font size. Results of ANOVA for reading preference, design preference, total preference were grouped by post-analysis LSD (Least Significant Difference). Among users, display ratio (16:9, 21:9), and font size (9pt) were preferred. In conclusion, 16:9 display ratio and 9pt are adaptable for text information in 1.3inch circle display. Conclusion: From the study, it is shown that 16:9 display ratio and 9pt size are more adaptable for text information in 1.3inch circle display than others. It is mainly due to the fact that the order of frame ratio and font size may affect the usability of reading long text information in a small circle display. Therefore, when developers design a circle display, the square frame ratio and font size are required to be considered according to circle size. Application: The 16:9 display ratio and 9pt font size may be utilized as a text information frame in the circle display design guideline for smartwatch.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2002년도 춘계학술대회
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• pp.243-247
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• 2002

This paper deals with the problem of determining the buyer's economic lot sizing policy for exponentially deteriorating products under trade credit. Assuming that the supplier's credit terms are already known and the length of delay is a function of the buyer's order size, we formulate the mathematical model and the solution algorithm is developed based on the properties of an optimal solution.

• 소성∙가공
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• 제22권7호
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• pp.394-400
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• 2013

Microforming is a very efficient and economical technology to fabricate very small metallic parts in various applications. In order to extend the use of this forming technology for the production of microparts, the size effect, which occurs with the reduction of part size and affects the forming process significantly, must be thoroughly investigated. In this study, the tribological size effect in microforming was studied using modeling and scaled ring compression experiments. A micro-scale friction approach based on the slip-line field theory and lubricant pocket model was used to understand the friction mechanism and explain the tribological size effect. Ring compression tests were performed to analyze the interfacial friction condition from the deformation characteristics of the ring specimens. In addition, finite element analysis results were utilized to quantitatively determine the size-dependent frictional behavior of materials in various process conditions. By comparing theoretical results and experimental measurements for different size factors, the accuracy and reliability of the model were verified.

• 대한가정학회지
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• 제49권10호
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• pp.49-56
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• 2011

The purpose of this study is to research the difference between the size suggested by brand uniforms and the size suitable for high school girls. We compared and analyzed the size system of brand uniforms after researching the wearing conditions of uniforms of 4 brands (A, B, C, D) in order to establish a size system of brand uniforms that fits different body types of teenagers. First, we conduct research on the actual condition of brand uniforms worn by high school girls, and investigate unsatisfactory factors and problems. Second, we actually measure the uniform size of each brand and analyze measurement differences between each brand. Our results show each brand uniform has different size specifications and the importance of appropriate size specification is greater as students select uniform based on design and brand awareness rather than body size. Compared with the average body size the skirt and especially the blouse is much smaller with no extra room compared with standard size 85 blouses and size 71 skirts. Therefore, the adjustment of size specification is needed in brand school uniforms. However, a larger scale investigation is needed as this study was conducted with a limited sample size.