• Electronics and Telecommunications Trends
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• v.31 no.2
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• pp.84-94
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• 2016

지난 60여 년간은 고전정보에 기반한 통신, 저장, 처리 능력이 비약적으로 발전하였다. 이 과정에서 가장 많이 사용된 방법은 정보소자의 크기를 감소시키는 방법이었는데, 이러한 접근법은 최근에 그 한계에 도달하고 있다. 이러한 한계를 극복하기 위해서 다양한 접근법이 연구되고 있으며, 궁극적으로는 양자역학적 현상에 기반하는 양자정보가 사용될 것으로 예상된다. 양자정보는 크게 계산성과 보안성을 향상시키는데, 이에 따라서 향후 ICT 전반에서 많은 변화가 생길 것으로 예상된다. 본고에서는 특히 양자정보에 기반한 양자컴퓨팅을 중심으로, 양자정보의 발현과 관련한 역사적 흐름, 양자정보에 기반한 정보처리의 핵심요소, 양자컴퓨팅 구현 방법론, 양자컴퓨팅 활용 방법론, 현재의 기술수준을 소개한다. 마지막으로 ICT의 경제의존도 및 사회몰입도가 높은 우리나라가 이러한 ICT패러다임의 전환기에서 과연 무엇을 어떻게 준비해야 하는지도 살펴본다.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1094-1099
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• 2003

Nanometer-sized structures are being applied to many fields including micro/nano electronics, optoelectronics, quantum computing, biosensors, etc. Multi-scale analysis technology is required for designing the reliable nanometer-sized structures and predicting their mechanical, chemical and electronic behaviors. In this paper, some techniques for multi-scale analysis are reviewed and their applicability and limitation are discussed. Research activity of nano process analysis team in KIMM is outlined. Especially, we concentrate on OCTA of Nagoya University in Japan for the analysis of polymeric materials. Detailed structure of OCTA is described and some examples are presented.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1927-1931
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• 2003

Nanometer-sized structures are being applied to many fields including micro/nano electronics, optoelectronics, quantum computing, biosensors, etc. Micro contact printing is one of the most promising methods for manufacturing the nanometer-sized structures. The crucial element for the micro contact printing is the nano-resolution printing technique using polymeric stamps. In this study, a multi-scale analysis scheme for simulating the micro contact printing process is proposed and some useful analysis results are presented. Using the slip-link model [1], the dependency of viscoelasticity on molecular weight of polymer stamp is predicted. Deformation behaviors of polymeric stamps are analyzed using finite element method based upon the predicted viscoelastic properties.

• Annual Conference of KIPS
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• 2017.11a
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• pp.360-362
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• 2017

올해 초, 구글(Google)이 SHA-1의 충돌 현상을 입증했다. 이것은 모든 타 암호 알고리즘 역시 안전할 수 없다는 것을 뜻하며, 향후 SHA-256을 사용하는 비트코인도 취약해질 수 있음을 의미한다. 이유인즉슨, 비트코인에서 사용되는 암호 및 해시 알고리즘은 답을 찾기 위해 상당한 시간이 소요되지만, 양자 컴퓨터의 큐비트를 바탕으로 하는 연산처리 능력은 그 시간을 대폭 감소시킬 수 있기 때문이다. 본 논문에서는 이와 같은 양자 컴퓨터가 비트코인에 얼마나 위협적일 수 있는지와 더불어 양자 컴퓨터 출현에 대비하고자 등장한 새로운 암호 화폐인 Byteball 및 QRL코인을 살펴보고자 한다.

• Annual Conference of KIPS
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• 2016.04a
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• pp.2-5
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• 2016

현재까지는 양자 컴퓨터의 계산 성능에 대한 알고리즘 수준의 연구가 대부분이었다. 본 연구에서는 이러한 알고리즘 수준 분석의 한계를 넘기 위해 조금 더 정교한 어셈블리 코드 수준에서의 정량적 분석을 진행하였다. 이 과정에서 현재 사용가능한 두 개의 양자 컴파일러와 두 개의 양자 알고리즘을 분석하였다. 이에 따라서 다음과 같은 두 가지 특성을 확인하였다. 첫 번째로 양자컴퓨터는 어셈블리 코드 수준에서도 충분한 성능향상 효과가 있음을 확인하였다. 두 번째로 고전컴파일러와 달리 양자컴파일러의 실행시간은 입력 값에 의존함을 확인하였다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.5
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• pp.1099-1112
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• 2018

The field of post-quantum cryptography (PQC) is an active area of research as cryptographers look for public-key cryptosystems that can resist quantum adversaries. Among those categories in PQC, code-based cryptosystem provides high security along with efficiency. Recent works on code-based cryptosystems focus on the side-channel resistant implementation since previous works have indicated the possible side-channel vulnerabilities on existing algorithms. In this paper, we recovered the secret key in HyMES(Hybrid McEliece Scheme) using a single power consumption trace. HyMES is a variant of McEliece cryptosystem that provides smaller keys and faster encryption and decryption speed. During the decryption, the algorithm computes the parity-check matrix which is required when computing the syndrome. We analyzed HyMES using the fact that the joint distributions of nonlinear functions used in this process depend on the secret key. To the best of our knowledge, we were the first to propose the side-channel analysis based on joint distributions of leakages on public-key cryptosystem.

• Journal of applied mathematics & informatics
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• v.25 no.1_2
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• pp.435-443
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• 2007

Computing the interior spectrum of large sparse generalized eigenvalue problems $Ax\;=\;{\lambda}Bx$, where A and b are large sparse and SPD(Symmetric Positive Definite), is often required in areas such as structural mechanics and quantum chemistry, to name a few. Recently, CG-type methods have been found useful and hence, very amenable to parallel computation for very large problems. Also, as in the case of linear systems proper choice of preconditioning is known to accelerate the rate of convergence. After the smallest eigenpair is found we use the orthogonal deflation technique to find the next m-1 eigenvalues, which is also suitable for parallelization. This offers advantages over Jacobi-Davidson methods with partial shifts, which requires re-computation of preconditioner matrx with new shifts. We consider as preconditioners Incomplete LU(ILU)(0) in two variants, ever-relaxation(SOR), and Point-symmetric SOR(SSOR). We set m to be 5. We conducted our experiments on matrices from discretizations of partial differential equations by finite difference method. The generated matrices has dimensions up to 4 million and total number of processors are 32. MPI(Message Passing Interface) library was used for interprocessor communications. Our results show that in general the Multi-Color ILU(0) gives the best performance.

• Bulletin of the Korean Chemical Society
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• v.24 no.6
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• pp.763-770
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• 2003

The $BH_5$ molecule, which is suggested as an intermediate of the acidolysis of $BH_4^-$, contains a weak two-electron-three-center bond and it requires extremely high-level of theories to calculate the energy and structure correctly. The structures and energies of $BH_5$ and the transition state for the hydrogen scrambling have been studied using recently developed multi-coefficient correlated quantum mechanical methods (MCCMs). The dissociation energies and the barrier heights agree very well with the previous results at the CCSD(T)/ TZ(3d1f1g, 2p1d) level. We have also calculated the potential energy curves for the dissociation of $BH_5$ to $BH_3$ and $H_2$. The lower levels of theory were unable to plot correct potential curves, whereas the MCCM methods give very good potential energy curves and requires much less computing resources than the CCSD(T)/ TZ(3d1f1g,2p1d) level. The potential energy of the $BH_5$ scrambling has been obtained by the multiconfiguration molecular mechanics algorithm (MCMM), and the rates are calculated using the variational transition state theory including multidimensional tunneling approximation. The rate constant at 300 K is 2.1 × $10^9s^{-1}$, and tunneling is very important.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.1
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• pp.45-56
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• 2013

When a signer signs a message, strong designated verifier signature allows the signer to designate a verifier. Only the designated verifier can make sure that the signature is generated by the signer. In addition, no one except the designated verifier can know the signature generated by some signer. In this paper, we propose an identity-based strong designated verifier signature scheme where users' public keys are identities. Our proposed scheme is the first identity-based strong designated verifier scheme from lattices. Naturally, our proposed scheme is secure against quantum computing attacks and has low computational complexity.

• Advances in nano research
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• v.1 no.3
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• pp.133-151
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• 2013

The availability of advanced nanotechnological methodologies (experimental and theoretical) has widened the investigation of biological/organic matter in interaction with substrates. Minerals are good candidates as substrates because they may present a wide variety of physico-chemical properties and surface nanostructures that can be used to actively condense and manipulate the biomolecules. Scanning Probe Microscopy (SPM) is one of the best suited techniques used to investigate at a single molecule level the surface interactions. In addition, the recent availability of high performance computing has increased the possibility to study quantum mechanically the interaction phenomena extending the number of atoms involved in the simulation. In the present paper, firstly we will briefly introduce new SPM technological developments and applications to investigate mineral surfaces and mineral-biomolecule interaction, then we will present results on the specific RNA-mineral interaction and recent basics and applicative achievements in the field of the interactions between other fundamental biological molecules and mineral surfaces from both an experimental and theoretical point of view.