• 대한수학회보
• /
• 제41권4호
• /
• pp.779-783
• /
• 2004

A group G is said to satisfy the minimal condition on normal subgroups of infinite index if there does not exist an infinite properly descending chain $G_1$ > $G_2$ > ... of normal subgroups of infinite index in G. We characterize the structure of locally nilpotent groups satisfying this chain condition.

• 대한수학회보
• /
• 제47권4호
• /
• pp.687-691
• /
• 2010

In this article we will prove that a generalized radical group satisfying the maximal condition for subnormal subgroups of infinite order (the minimal condition for subnormal subgroups of infinite index, respectively) is soluble-by-finite. Such result generalizes that obtained by D. H. Paek in [5].

• 대한수학회보
• /
• 제45권1호
• /
• pp.105-109
• /
• 2008

We study the structure of metanilpotent groups satisfying the maximal condition on infinite normal subgroups or the minimal condition on normal subgroups of infinite index.

• 대한수학회보
• /
• 제44권4호
• /
• pp.763-769
• /
• 2007

We study the structure of abelian-by-nilpotent groups satisfying the maximal condition on infinite normal subgroups or the minimal condition on normal subgroups of infinite index.

• 충청수학회지
• /
• 제8권1호
• /
• pp.71-77
• /
• 1995

In this paper, we define a subgroup S(X, ${\gamma}$) of the group of automorphisms of universal minimal sets and give a necessary and sufficient condition for a minimal transformation group to be regular.

• 충청수학회지
• /
• 제16권1호
• /
• pp.73-79
• /
• 2003

A subgroup S(X, ${\gamma}$) of the group of automorphisms of a universal minimal transformation group is introduced and a necessary and sufficient condition for two subgroups to be identical is obtained.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
• /
• pp.918-923
• /
• 1989

This paper presents a stability condition for Astrom's minimal variance control(MVC) with mismatch of time delay for a SISO ARMAX model containing time delay. The proof of the condition presented here is based on the characteristic equation in the feedback system and its magnitude. This condition, from easy numerical calculation, is able to find the stability of the feedback system without knowing the real time delay.

• 대한수학회보
• /
• 제55권5호
• /
• pp.1339-1350
• /
• 2018

We will find a necessary and sufficient condition for unit Killing vector fields to be minimal and provide an application of the obtained result.

• Journal of the Korean Statistical Society
• /
• 제30권1호
• /
• pp.89-98
• /
• 2001

Brown and Proschan(1983) introduced a model for imperfect repair. At each failure of a device, with probability p, it is repaired completely or replaced with a new device(perfect repair), and with probability 1-p, it is returned to the functioning state, but it is only recovered to its condition just prior to failure(imperfect repair or minimal repair). In this paper, we limit the number of consecutive minimal repairs by n. We find some useful properties about $\mu$$_{k}$, the expected time between the k-th and the (k+1)-st repair under he assumption that only minimal repairs are performed. Then, we assign cost to each repair and find the value of n which minimized the long-run average cost for a fixed p under the condition that the life distribution F os the device is DMRL.L.

• 한국신뢰성학회:학술대회논문집
• /
• 한국신뢰성학회 2000년도 춘계학술대회 발표논문집
• /
• pp.63-70
• /
• 2000

Brown and Proschan(1983) introduced a model for imperfect repair. At each feilure of a device, with probability p, it is repaired completely or replaced with a new device(perfect repair), and with probability 1 - p, it is returned to the functioning state, but it is only recovered to its condition just prior to failure(imperfect repair or minimal repair). In this paper, we limit the number of consecutive minimal repairs by n. We find some useful properties about ${\mu}$$\_$k/, the expected time between the k-th and the (k + 1)-st repair under the assumption that only minimal repairs are performed. Then, we assign cost to each repair and find the value of n which minimizes the long-run average cost for a fixed p under the condition that distribution F of the device is DMRL.