• 대한수학회보
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• 제56권3호
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• pp.569-583
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• 2019

Given a graph G, the Motzkin and Straus formulation of the maximum clique problem is the quadratic program (QP) formed from the adjacent matrix of the graph G over the standard simplex. It is well-known that the global optimum value of this QP (called Lagrangian) corresponds to the clique number of a graph. It is useful in practice if similar results hold for hypergraphs. In this paper, we attempt to explore the relationship between the Lagrangian of a hypergraph and the order of its maximum cliques when the number of edges is in a certain range. Specifically, we obtain upper bounds for the Lagrangian of a hypergraph when the number of edges is in a certain range. These results further support a conjecture introduced by Y. Peng and C. Zhao (2012) and extend a result of J. Talbot (2002). We also establish an upper bound of the clique number in terms of Lagrangians for hypergraphs.

• 대한수학회보
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• 제54권3호
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• pp.1037-1067
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• 2017

Motzkin and Straus established a close connection between the maximum clique problem and a solution (namely graph-Lagrangian) to the maximum value of a class of homogeneous quadratic multilinear functions over the standard simplex of the Euclidean space in 1965. This connection and its extensions were successfully employed in optimization to provide heuristics for the maximum clique problem in graphs. It is useful in practice if similar results hold for hypergraphs. In this paper, we develop a homogeneous multilinear function based on the structure of hypergraphs and their complement hypergraphs. Its maximum value generalizes the graph-Lagrangian. Specifically, we establish a connection between the clique number and the generalized graph-Lagrangian of 3-uniform graphs, which supports the conjecture posed in this paper.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.56-56
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• 2010

Using first-principles density-functional theory calculations, we find dramatically different electronic states in the C chains generated on the H-terminated C(111) surface, depending on their length and parity. The infinitely long chain has $\pi$ electrons completely delocalized over the chain, yielding an equal C-C bond length. As the chain length becomes finite, such delocalized $\pi$ electrons are transformed into localized ones. As a result, even-numbered chains exhibit a strong charge-lattice coupling, leading to a bond-alternated structure, while odd-numbered chains show a ferrimagnetic spin ordering with a solitonlike structure. These geometric and electronic features of infinitely and finitely long chains are analogous to those of the closed (benzene) and open (polyacetylene) chains of hydrocarbons, respectively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.523-526
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• 1995

This paper presents an improved algorithm of optimal measurement system design with a reliability evaluation method for a large power system. The proposed algorithm is developed to cosider the observability and to achieve highest accuracy of the state estimator as well with the limited investment cost. When the effect on these dummy bus measurements is considered in the proposed algorithm the other errors in the power system is also detected and then analyzed until to achieve the limited values. By taking advantage of the matrix sparsity and the optimal bus ordering the memory and the time are successfully reduced in the P/C's and workstation's model. The improved program is successfully tested for IEEK sample system and KEPCO system with PSS/E lineflow calculated data package.

• 한국조경학회지
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• 제47권1호
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• pp.10-25
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• 2019

본 연구는 서울시의 문화재 수리공사의 발주현황에 관한 연구로써 각 지자체 및 산하 기관에서 발주되는 문화재 공사를 중심으로 하였으며, 연구의 범위로는 공간적으로는 서울시를 대상으로 하였고, 시간적 범위로는 2015년 10월부터 2017년 9월까지 2년으로 하였다. 그리고 서울시의 문화재 현황, 그리고 문화재 수리 예산을 알아봄으로써 문화재 공사의 발주규모를 파악할 수 있었다. 2년간의 문화재 공사의 발주 실태를 조사하여 총 발주 건수, 발주 시기 및 각 공종별 발주규모를 알 수 있었으며, 이러한 기초자료를 가지고 세부내역을 분석함으로써 각 문화재 공종별 혼입 실태를 파악할 수 있었다. 문화재 공사의 혼입 실태를 파악한 결과, 하나의 문화재 공사는 타 공종의 혼입 없이 완전히 시공하는데 어려움이 있음을 알게 되었고, 이에 대응할 수 있는 문화재공사 도급 방식을 제안하였다. 본 연구는 문화재공사 발주 성향을 분석함으로써 적절한 발주 방식을 제안하였고, 이것으로 현장에 적절한 문화재수리기술자 배치를 위한 기초자료로 활용할 수 있을 것이다. 특히 문화재 공사업에 있어서 조경은 문화재 경관을 책임지는 중요한 위치에 있으며, 이런 조경의 위상을 정립할 필요가 있음에도 불구하고, 문화재 공사업의 발주 실태와 조경공사의 위상을 밝힌 논문이 전혀 없으며, 이 논문은 그것에 대하여 서울시를 대상으로 실증적으로 밝혀, 조경공사의 오롯한 위상 정립을 위한 제안을 함과 동시에 각 문화재 수리분야의 업역 확보에도 크게 기여할 수 있을 것이다.

• 전자공학회논문지B
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• 제30B권11호
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• pp.74-83
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• 1993

This paper presents methodology which enables the derivation of goal ordering rules from the analysis of problem failures. We examine all the possible ways of taking actions that lead to failures. If there are restrictions imposed by a problem state on possible actions to be taken, the restrictions manifest themselves in the form of a restricted set of possible operator bindings. Our method makes use of this observation to derive general control rules which are guaranteed to be correct. The overhead involved in learning is very low because this methodology needs only small amount of data to learn from namely, the goal stacks from the leaf nodes of a failure search tree. Empirical tests show that the rules derived by our system PAL couperform those derived by other systems such as PRODIGY and STATIC.

• 반도체디스플레이기술학회지
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• 제19권3호
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• pp.49-54
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• 2020

We studied the electronic and magnetic properties for the Mn-doped chalcopyrite (CH) AlAs, GaAs, and AlGaAs₂ semiconductor by using the first-principles calculations. The chalcopyrite AlGaP₂, AlGaAsP, and AlGaAs₂ compounds have a semiconductor characters with a small band-gap. The interaction between Mn-3d and As-4p states at the Fermi level dominate rather than the other states. The ferromagnetic ordering of dopant Mn with high magnetic moment is induced due to the Mn(3d)-As(4p) strong coupling, which is attributed by the partially filled As-4p bands. The holes are mediated with keeping their 3d-electrons, therefore the ferromagnetic state is stabilized by this double-exchange mechanism. We noted that the ferromagnetic state with high magnetic moment is originated from the hybridized As(4p)-Mn(3d)-As(4p) interaction mediated by the holes-carrier.

• 한국시뮬레이션학회논문지
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• 제3권2호
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• pp.27-36
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• 1994

In many real-world simulation studies the several measures of performance are of interest simultaneously. There exist very limited number of studies that explain and suggest the methods or procedures of inferencing the system performances at the same time. This study presents a procedure for determining the number of simulation observations required to achieve the prespecified confidence level for several measures of system performance. Mean values are selected as the measures, for instance, expected ordering cost, expected holding cost, and expected shortage cost for a given period of time in the study of inventory problems. Basically, the batch means approach is applied and extended to develop an algorithm to carry out the procedure handling more than single parameter. The efficacy of the presented method is assessed through the experiments. The empirical results based on some stochastic systems such as queues and inventory problems show that the suggested method produces as excellent result in terms of the precision of estimated means and the number of observations required.

• Applied Science and Convergence Technology
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• 제24권3호
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• pp.47-52
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• 2015

The correlation between admittance and dielectric spectroscopy of dielectric relaxation in lead scandium noibate, have been investigated. Lead scandium niobate, with composition $PbSc_{0.5}Nb_{0.5}O_3$, was prepared by conventional solid state synthesis. Conductance Y'(G), susceptance Y"(B) and capacitance C of lead scandium niobate as a function of frequency and temperature were measured. From the temperature-dependence of RLC circuit, insight into physical significance of the dielectric properties of lead scandium niobate is obtained. The relative strong frequency dependent of dielectric properties in lead scandium niobate is observed, and the phase transition occurred at a broad temperature region. Also, the value of critical exponent ${\gamma}$=1.6 showed on heating process. The long relaxation times part enlarged diffuse by conductivity effects with increasing temperature, and the ordering between $Sc^{3+}$ and $Nb^{5+}$ in PSN influences complex admittance and dielectric properties. Confirmed the typical characteristic of lead-type relaxor in the Raman spectra of lead scandium niobate and major ranges are between 400 and $900cm^{-1}$.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 춘계 학술논문 발표대회
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• pp.215-216
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• 2015

In order to facilitate the introduction of BIM technology in the construction project of fact, many countries such as Singapore and the United States, is developing a roadmap of BIM technology development. To develop this, recently, it must be analyzed in advance the state of BIM technology domestic projects. In this study, we define the elements of technology BIM, and analyzed the current situation. In addition, I was evaluated and priority importance to the elemental technology derived. As a result, elemental technology most was the level inferior to foreign countries, and the field of ordering standard planning and has been highly valued and priority of particular importance, but currently, the level of domestic, analysis and most delayed has been. These results are judged to be useful in the development of the roadmap and direction of technological development of BIM in the future.