• Journal of IKEEE
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• v.18 no.4
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• pp.517-522
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• 2014

This paper investigates the consensus problem for linear multi-agent systems with an arbitrary network delay. The sufficient conditions for a state consensus of linear multi-agent systems are provided by using linear matrix inequalities. Moreover, it is shown that under the proposed protocol, the consensus can be achieved even in the presence of an arbitrarily large network delay. Finally, an illustrative example is given in order to show the effectiveness of our design method.

• Journal of Korean Society of Transportation
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• v.28 no.5
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• pp.131-139
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• 2010

The transport mode choice problem is to determine which of the alternative transport modes connecting an origin and destination will be used by a traveler. Most of the research relating to transport mode choice have mainly been focused on modeling, properties, and applications of the model, but rarely were concerned with equilibrium among the modes. This paper proves the equilibrium among the modes by using a logit mode choice model, and then verifies it with the Korean Transport Database (KTDB). In order to obtain such an equilibrium, this paper also presents a solution algorithm based on the fixed point theorem. The algorithm was tested with an example and confirmed the equilibrium solution.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.5
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• pp.959-972
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• 2021

Decentralized Identity is based on the concept of self-sovereign identity, in which holders manage and provide their own credentials. However, a procedure is required to obtain credentials from issuers, and there is a risk of mess personal information leaking due to negligence of the issuers. In this paper, we propose a peer decentralized identity system based on Peer DID technology that allows only participants to verify their identity in 1:1 or 1:N small groups by matching the holder with the issuer. It is directly connected to a mobile device using short-range wireless communications such as bluetooth, and the holders create and provide their own credentials in person to the other party, thus fully realizing the self-sovereignty identity. The proposed system can simplify the identification process, improve security and privacy, and reduce costs. Furthermore, an extended architecture is possible to connect the proposed system and the distributed ledger to identify users in other domains. In the future, based on various technologies, it is also necessary to expand research on identity systems that can be utilized for human-to-thing and things-to-things authentication.

• Journal for History of Mathematics
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• v.23 no.3
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• pp.57-73
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• 2010

Transcendental numbers are important in the history of mathematics because their study provided that circle squaring, one of the geometric problems of antiquity that had baffled mathematicians for more than 2000 years was insoluble. Liouville established in 1844 that transcendental numbers exist. In 1874, Cantor published his first proof of the existence of transcendentals in article [10]. Louville's theorem basically can be used to prove the existence of Transcendental number as well as produce a class of transcendental numbers. The number e was proved to be transcendental by Hermite in 1873, and $\pi$ by Lindemann in 1882. In 1934, Gelfond published a complete solution to the entire seventh problem of Hilbert. Within six weeks, Schneider found another independent solution. In 1966, A. Baker established the generalization of the Gelfond-Schneider theorem. He proved that any non-vanishing linear combination of logarithms of algebraic numbers with algebraic coefficients is transcendental. This study aims to examine the concept and development of transcendental numbers and to present students with its open problems promoting a research on it any further.

• Annual Conference of KIPS
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• 2021.11a
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• pp.309-312
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• 2021

최근 사회는 디지털기술을 기반으로 비대면전환이 빠르게 이루어지고 있다. 이에 디지털 신분증과 디지털 신원인증에 대한 관심이 증가하고 있다. 기존 오프라인에서 사용되고 있는 플라스틱 신분증은 분실 및 위·변조의 위험성이 존재한. 또한 현재 온라인에서 널리 사용되고 잇는 신원인증 모델들을 데이터의 주권이 사용자가 아닌 서비스 제공자에게 있다는 문제점이 있다. 위와 같은 문제들을 해결하고 사용자의 신원정보를 효과적으로 관리하기 위해 분산신원증명의 필요성이 제기되었다. 본 논문에서는 분산신원증명의 구조와 서비스 적용 사례에 대해 살펴본다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.2 no.1
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• pp.70-75
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• 1992

A model for a microstructural residual stress in a ferroelectric material is proposed. Based on this model, two facts are estimated. One of them is that the residual stress on a grain boundary is larger than that on a domain boundary. Another one is that the microstructural residual stress decrease with increasing grain size. These facts are confirmed by the microcrack morphology and the dependence of dielectric constant hysteresis between heating and cooling on grain size in $PbZr_{0.4}Ti_{0.6}O_3$ ceramics.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2014.11a
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• pp.259-260
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• 2014

본 논문에서는 영상에 존재하는 운동정보를 이용하여 관심맵을 얻는 방법을 제안한다. 운동의 크기, 방향, 그리고 영상의 색을 이용한다. 이를 이용함으로써 기존의 static image에서 구하는 관심맵보다 향상된 결과를 얻을 수 있다. 실험에서는 다양한 모션이 존재하는 영상을 이용하여 제안방법의 우수성을 증명하였다.

• Review of KIISC
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• v.24 no.1
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• pp.32-38
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• 2014

본 논문은 수년간 급격하게 증가되어 많은 피해를 초래하고 있는 악성코드를 탐지하기 위한 기법을 제안한다. 악성코드 제작자로부터 생산되고 인터넷에 유포되는 대부분의 악성코드는 처음 개발된 제로-데이 악성코드의 코드 일부를 그래도 재사용하는 경우가 많다. 이러한 특징에 의해 악성코드 변종들 사이에는 악의적 행위를 위해 사용되는 함수들 중 공통으로 포함되는 코드들이 존재하게 된다. 논문에 저자는 이점에 착안하여 코드 재사용 검사 여부를 통한 악성코드 변종 탐지 기법을 제안하고 있다. 그리고 변종 샘플을 이용한 변종 탐지의 가능성을 증명하는 실험과 실제 공통으로 존재하는 재사용 코드 일부(함수) 추출 정확성을 알아보는 실험을 수행하여 주장을 뒷받침한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.11a
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• pp.48-49
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• 2013

Saliency는 인간의 시각에서 관심 영역이나 객체를 찾기 위한 기법으로 최근 영상 리타겟팅, 영상분할 등에 다양하게 활용되고 있다. 기존 제안된 방법들을 전체영상을 대상으로 saliency map을 구하게 되어, 복잡한 객체들의 구성, 큰 전경객체들의 존재 등의 경우에는 성능이 저하되는 문제점이 있다. 따라서 본 논문에서는 배경이 존재하는 영상들을 대상으로 기존 방식중의 하나인 histogram based contrast(HBC)을 개선하는 방법을 제안한다. 배경영역의 빈도확률을 HBC에 적용하여 배경에 존재하는 픽셀값의 saliency을 감소하면, 상대적으로 전경에 존재하는 픽셀들의 saliency는 증가하게 된다. 실험에서는 제안한 기법으로 배경의 saliency는 감소하고, 전경객체는 증가하는 것을 증명하였다.

• Journal for History of Mathematics
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• v.24 no.3
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• pp.37-58
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• 2011

The development of recent Mathematical Logic is mostly originated in Hilbert's Proof Theory. The purpose of the plan so called Hilbert's Program lies in the formalization of mathematics by formal axiomatic method, rescuing classical mathematics by means of verifying completeness and consistency of the formal system and solidifying the foundations of mathematics. In 1931, the completeness encounters crisis by the existence of undecidable proposition through the 1st Theorem of G?del, and the establishment of consistency faces a risk of invalidation by the 2nd Theorem. However, relative of partial realization of Hilbert's Program still exists as a fruitful research program. We have tried to bring into relief through Curry-Howard Correspondence the fact that Hilbert's program serves as source of power for the growth of mathematical constructivism today. That proof in natural deduction is in truth equivalent to computer program has allowed the formalization of mathematics to be seen in new light. In other words, Hilbert's program conforms best to the concept of algorithm, the central idea in computer science.