• 대한수학회보
• /
• 제49권6호
• /
• pp.1199-1211
• /
• 2012

In this paper we give an introduction to the theory of universal central extensions of perfect Lie algebras. In particular, we will provide a model for the universal coverings of Lie tori and we show that automorphisms and derivations lift to the universal coverings. We also prove that the universal covering of a Lie ${\Lambda}$-torus of type ${\Delta}$ is again a Lie ${\Lambda}$-torus of type ${\Delta}$.

• Bulletin of the Korean Chemical Society
• /
• 제11권4호
• /
• pp.332-333
• /
• 1990

The most general algebraic Hamiltonian for vibron model of diatomic molecules is obtained by using the theorems on the Jordan Schwinger representations of Lie groups.

• 대한수학회보
• /
• 제47권6호
• /
• pp.1131-1138
• /
• 2010

In the present paper, we evaluate an analytic formula as a solution of Susceptible Infective (SI) model problem for communicable disease in which the daily contact rate (C(N)) is supposed to be varied linearly with population size N(t) that is large so that it is considered as a continuous variable of time t. Again, we introduce some Lie group of operators to make an extension of above analytic formula of the determin-istic epidemics model problem. Finally, we discuss some of its particular cases.

• 호남수학학술지
• /
• 제40권2호
• /
• pp.265-280
• /
• 2018

In this study, we firstly define equations of motion based on the traditional model Newtonian mechanics in terms of the Frenet frame adapted to the trajectory of the moving particle in Lie groups. Then, we compute energy on the moving particle in resultant force field by using geometrical description of the curvature and torsion of the trajectory belonging to the particle. We also investigate the relation between energy on the moving particle in different force fields and energy on the particle in Frenet vector fields.

• 대한수학회보
• /
• 제52권4호
• /
• pp.1297-1303
• /
• 2015

We study Samelson products on models of function spaces. Given a map $f:X{\rightarrow}Y$ between 1-connected spaces and its Quillen model ${\mathbb{L}}(f):{\mathbb{L}}(V){\rightarrow}{\mathbb{L}}(W)$, there is an isomorphism of graded vector spaces ${\Theta}:H_*(Hom_{TV}(TV{\otimes}({\mathbb{Q}}{\oplus}sV),{\mathbb{L}}(W))){\rightarrow}H_*({\mathbb{L}}(W){\oplus}Der({\mathbb{L}}(V),{\mathbb{L}}(W)))$. We define a Samelson product on $H_*(Hom_{TV}(TV{\otimes}({\mathbb{Q}}{\oplus}sV),{\mathbb{L}}(W)))$.

• 대한기계학회논문집A
• /
• 제25권5호
• /
• pp.850-856
• /
• 2001

Even though the hydraulic servo system has been widely used in industrial and military equipments since it has a lot of advantages, it is not easy to design controller due to the high nonlinearities and the parametric uncertainties. The dynamic behavior of the real process in the hydraulic servo system differs from that described by its model because the model is linearized. Another reason of the difference is caused by the variety of parameters, since the system parameters of the dynamic equation are affected by the operating conditions such as temperature and pressure. In this study, the designing process of the MRNC with a PID compensator is introduced and applied to the load sensing hydraulic servo system. The results show that the designed controller guarantees the robust control performance despite of both the nonlinearities and the parametric uncertainties.

• 한국안전학회지
• /
• 제26권6호
• /
• pp.31-44
• /
• 2011

This paper has presented a finite element analysis of structural behaviour of box culvert during and after fires. The fire tests were carried out in a furnace on RC slabs using the ISO 834 standard fire curve. The load capacity after cooling of the RC slab that was not loaded during the fire tests was evaluated by means of additional 3 points bending tests. In the past, stress-strain models of concrete under fire loading have been proposed by several researchers. Comparisons are made with the load-displacement relations of RC slabs after fire loading using the existing stress-strain models with temperature, such as Schneider, EUROCODE 2, Lie, Shi and Nan model. By comparing the load-displacement relations, Lie model was found to result in a maximum load about 2.0% higher than that of test. Based on the fire test results of RC slabs, this paper presents an extensive analytical study on the fire response of box culvert during and after fires.

• 한국국방경영분석학회지
• /
• 제3권1호
• /
• pp.137-150
• /
• 1977

The effectiveness of an actual combat tank system is analyzed. A measure of effectiveness which includes performance and reliability called pseudo-reliability is introduced. A model is introduced to optimize the design of the system in which the system pseudo-reliability is maximized subject to cost constraint. This model is a nonlinear programming problem and is solved by the sequential unconstrained minimization technique (SUMT). A numerical exampl with actual data from the test evaluation of five combat tanks is used to illustrate the model.

• 대한교통학회지
• /
• 제32권1호
• /
• pp.50-62
• /
• 2014

우리나라의 교통사고는 2000년 이후 감소세를 보이고 있으나 2006년 이 후 감소세가 둔화되고 있는 실정이다. 과거 교통안전의 개선방안으로 도로선형 개선과 같은 물리적 개선방안을 통해 사고감소에 큰 효과를 보았으나 이에 대한 효용성이 한계에 왔다고 볼 수 있다. 본 연구에서는 운전자 성격특성과 교통사고가 어떠한 영향을 미치는지 살펴보고자 한다. 이를 위해 사고를 유발한 운전자들을 대상으로 성격검사를 포함한 설문을 시행하였다. 또한, 교통사고와 연관성이 높은 것으로 제시되고 있는 '사고호발성향'에 대한 영향력을 살펴보고자 한다. 이를 위해 연구대상자는 사고를 1건 이상 유발한 운전자들만을 대상으로 사고 다발 특성모형을 구축하였다. 그 결과, 성격특성별로는 총 9개(신경증적 경향성(N), 허위성(L), 정신병적*신경증적(PN), 정신병적*허위성(PL), 외향성*허위성(EL), 신경증적*허위성(NL), 충동성(IMP), 모험성(VEN), 감정이입성(EMP))의 항목이 유의한 성격요인으로 나타났다. 이 중, 단일성격항목에 편중된 성격은 사고를 증가시키는 영향이 높은 것으로 나타났다. 단, 복합성격항목도 함께 높은 경우에는 사고를 증가시키는 영향력을 다소 감소시키는 것으로 나타났다.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
• /
• pp.1133-1138
• /
• 1991

A control of nonlinear system is motivated by the fact that all real plants are nonlinear systems and model identification introduces parameter errors. The purpose of this study is to design a Discrete Variable Structure Controller(DVSC) for single-rod hydraulic cylinder system. The model contains uncertain parameters which we known to lie upper and lower bounds. In the design of DVSC, the boundary layer concept was adopted to reduce cattering. The DVSC was evaluated through digital computer simulation and compared with a VSC (analog controller).