• Communications of the Korean Mathematical Society
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• v.20 no.3
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• pp.539-546
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• 2005

Let ${X,\;X_n|n\;\geq\;1}$ be a sequence of identically negatively associated random variables under some conditions. We discuss strong laws of weighted sums for arrays of negatively associated random variables.

• 한국경영정보학회:학술대회논문집
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• 2007.06a
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• pp.333-338
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• 2007

소프트웨어 개발 프로젝트의 15%는 시작하기도 전에 종결되며, 66%의 프로젝트는 실패로 간주되고 있다. 또한 평균적으로, 완료된 프로젝트의 43%가 비용을 초과하는 것으로 나타났다. 실제로 2002년도 미국에서 소프트웨어 프로젝트의 투자 실패로 인한 손실은 비용의 초과로 생긴 170억 달러를 포함해 총 손실 금액이 380억 달러인 것으로 추정하고 있다. 이러한 문제점을 해결하고자 하는 여러 시도 중에 하나가 ISBSG(International Software Benchmarking Standard Group, 2004)으로, 소프트웨어 프로젝트 관련 데이터를 국제적으로 수집하여 위와 같은 문제의 원인을 밝히고자 노력하고 있다. 본 연구는 ISBSG에서 수집한 데이터를 이용해 소프트웨어 시스템과 관련된 요인 중에서 기능성 품질, 문서화품질, 훈련정도, 소프트웨어크기, 전체결함수, 사업요구사항충족, 사용편리성, 목표달성이라는 6개 변수 간의 연관성을 분석하였다. 분석대상 프로젝트는 49개이고, 분석 방법으로는 SURE(Seemingly Unrelated REgression)를 사용하였다. 분석 결과 소프트웨어 기능성품질은 사업요구사항충족, 사용편리성과 정의 관계를 가지며, 사용편리성은 사업요구사항충족과 정의 관계를 가지는 것으로 밝혀졌다. 또한 사업요구사항충족은 목표달성과 정의 관계를 가지고 있다.

• Journal of the Korean Mathematical Society
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• v.49 no.3
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• pp.515-536
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• 2012

This work focuses on the general decay stability of nonlinear stochastic differential equations with unbounded delay. A Razumikhin-type theorem is first established to obtain the moment stability but without almost sure stability. Then an improved edition is presented to derive not only the moment stability but also the almost sure stability, while existing Razumikhin-type theorems aim at only the moment stability. By virtue of the $M$-matrix techniques, we further develop the aforementioned Razumikhin-type theorems to be easily implementable. Two examples are given for illustration.

• Bulletin of the Korean Mathematical Society
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• v.48 no.6
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• pp.1137-1146
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• 2011

Let {$X_i$, $i{\geq}1$} be a sequence of i.i.d. nondegenerate random variables which is in the domain of attraction of the normal law with mean zero and possibly infinite variance. Denote $S_n={\sum}_{i=1}^n\;X_i$, $M_n=max_{1{\leq}i{\leq}n}\;{\mid}S_i{\mid}$ and $V_n^2={\sum}_{i=1}^n\;X_i^2$. Then for d > -1, we showed that under some regularity conditions, $$\lim_{{\varepsilon}{\searrow}0}{\varepsilon}^2^{d+1}\sum_{n=1}^{\infty}\frac{(loglogn)^d}{nlogn}I\{M_n/V_n{\geq}\sqrt{2loglogn}({\varepsilon}+{\alpha}_n)\}=\frac{2}{\sqrt{\pi}(1+d)}{\Gamma}(d+3/2)\sum_{k=0}^{\infty}\frac{(-1)^k}{(2k+1)^{2d+2}}\;a.s.$$ holds in this paper, where If g denotes the indicator function.

• Bulletin of the Korean Mathematical Society
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• v.43 no.3
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• pp.479-486
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• 2006

Let $Z_n(s,\;f)=n^{-1}\;{\sum}^{ns}_{i=1}(f(X_i)-Pf)$ be the sequential empirical process based on the independent and identically distributed random variables. We prove that convergence problems of $sup_{(s,\;f)}|Z_n(s,\;f)|$ to zero boil down to those of $sup_f|Z_n(1,\;f)|$. We employ Ottaviani's inequality and the complete convergence to establish, under bracketing entropy with the second moment, the almost sure convergence of $sup_{(s,\;f)}|Z_n(s,\;f)|$ to zero.

• Communications for Statistical Applications and Methods
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• v.6 no.2
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• pp.585-594
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• 1999

Let {$X_{nj}$, 1$\leq$j$\leq$n,j$\geq$1} be a triangular array of random variables which are neither independent nor identically distributed. The almost sure convergences of randomly weighted partial sums of the form $$\sum_n^{j=1}$$ $W_{nj}$$X_{nj} are studied where {Wnj 1$\leq$j$\leq$n, j$\geq$1} is a triangular array of random weights. Application regarding the Efron bootstrap is also introduced.

• Journal of Technologic Dentistry
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• v.29 no.1
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• pp.133-138
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• 2007

In this study, the castability and of commercially pure titanium(c.p.Ti) grade according to the casting condition which are the vacuum condition in casting machine and mold temperature of investment, was investigated. Argon-arc melt/centrifugal casting machine was used for casting the specimens. The microstructure and mechanical properties were evaluated by using optical microscope. The results were as follows; 1. It could make a sure that there's relatively not much defect of casting body of c.p.Ti according to the deference of air pressure. 2. It could make sure that it formed porosity on the surface inside of the casting body of c.p.Ti according to deferent temperature. and on excellent castability was below $200^{\circ}C$ 3. As the mold temperature of investment was increased, the lamellar structure of phase and coarse grains were shown, especially under 42MPa.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.63
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• pp.245-260
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• 2014

This study is aimed to summarize a tense situation of Risk management for Kaesong Industrial Business Enterprise in 2013 and to investigate trade insurance of K-sure. Now we have to find a new way to protect Kaesong Industrial Business Enterprises from uncertain environment and also need to prevent a recurrence of parallel cases in the domain of South-North economic cooperation in Korean peninsula. There are two method to protect Kaesong Industrial Business Enterprises. First they rely on the Korea government for protection. Second they need to effect trade insurance of K-sure. such as Export Credit Guaranty or Short-term Export Insurance. They shall create a wise predictable environment to protect Kaesong Industrial Business Enterprises themselves without resort to Korea government. Of course there are many things left behind to consider I hope it will be helpful to those who prepare South-North economic cooperation especially in Kaesong Industrial Complex.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.516-516
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• 2000

We propose a neuron model that is possible to learn three-dimensional movement. The neuron model by imitating structure of a neuron, has the system resemble a neuron. We considered a neuron system based on the arguments, and wished to examine whether the system had reasonable function. Koch, Poggio and Torre believed that inhibition signal would shunt excitation signal on the dendrites. They believed that excitation signal operated input-signals and inhibition did as delayed ones. Thus, they were sure that function for directional selectivity was arisen by the shunting. Koch's concept is so important; therefore, we construct the neuron system with their concept. The neuron system makes the shunting function; thus, the model may have a function for directional selectivity. We initialized the connections and the dendrites by random data, and trained them by the back-propagation algorithm for three-dimensional movement. We made sure the defection of three-dimensional movement in the system.

• The Journal of Natural Sciences
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• v.8 no.2
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• pp.5-7
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• 1996

Let {X,$X_n$,n$\geq$1} be i.i.d. random variables with mean zero and {$a_ni$, 1$\leq$i$\leq$n,n$\geq$1} a triangular array of constants. In this paper we give sufficient conditions on X and {$a_ni$} such that $sum_{i=1}^n$$a_{ni}$$X_i$ converges to zero almostly surely.