• 정보처리학회논문지C
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• 제17C권5호
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• pp.399-406
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• 2010

유비쿼터스 네트워크 환경에서 다양한 데이터 서비스가 가능해지면서 악의적인 공격자나 내부 사용자에 의한 보안 취약성 및 프라이버시 침해로 인한 문제를 해결하기 위해 다양한 콘텐츠나 대용량 데이터의 안전한 보안 관리 문제가 주요 이슈로 떠오르고 있다. 기존 다항식 기반을 이용한 Ito, Saito, Nishizeki 할당 방식은 분산된 비밀정보를 복원하기 위해 Share 모두가 필요하게 된다. 반면, 본 제안 방식의 경우, 임계치 이상의 Share가 모아지면 비밀정보를 복원할 수 있다. 또한, 데이터를 분산 복원하는 분산 DBMS 운영상의 효과 특히, 데이터베이스(DB) 서버 및 Share 선택의 규칙성이 있고 조합적 구조인 Combinatorial Design상의 파라메터 t,v,k를 이용함으로써 구현상의 유연성(flexibility)을 갖는다. 본 논문에서는 Share의 할당 문제를 해결하고자 비밀분산 방식을 이용하여 데이터를 분산저장관리 할 때 Share의 할당을 위해 t-(v,k,1) 디자인이 갖는 행렬구조를 적용시킴으로써 새롭게 Share 할당법을 구성하고 데이터 분산저장관리에의 응용에 대해 검토한다.

• 한국안전학회지
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• 제15권4호
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• pp.69-77
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• 2000

This paper presents a study for decision method of human body safety according to power load fluctuation of the Chechon area. To cope with substantial electromagnetics analysis, the safety assessments were analyzed the double 154 [kV] T/L, 345 [kV] T/L, Chechon-Ichon, Chechon-Youngju, respectively. As the results of case study, in case of 345 [kV] T/L, the electric field value was 11.4927 [kV/m], magnetic field value was 0.4622 [G] at the point about 7 [m] away from the line in severest case. The results showed that the membership of a proposition fuzzy '11.4937 [kV/m] is hazardous' is 0.7063 for the severest case in case of 345 [kV] T/L. As the analytic results using the fuzzy qualifier term, the membership in case of very false is 0.0862 and fairly false is 0.5419, respectively.

• 대한수학회논문집
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• 제20권4호
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• pp.671-683
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• 2005

The set of all $m\;{\times}\;n$ matrices with entries in $\mathbb{Z}_+$ is de­noted by $\mathbb{M}{m{\times}n}(\mathbb{Z}_+)$. We say that a linear operator T on $\mathbb{M}{m{\times}n}(\mathbb{Z}_+)$ is a (U, V)-operator if there exist invertible matrices $U\;{\in}\; \mathbb{M}{m{\times}n}(\mathbb{Z}_+)$ and $V\;{\in}\;\mathbb{M}{m{\times}n}(\mathbb{Z}_+)$ such that either T(X) = UXV for all X in $\mathbb{M}{m{\times}n}(\mathbb{Z}_+)$, or m = n and T(X) = $UX^{t}V$ for all X in $\mathbb{M}{m{\times}n}(\mathbb{Z}_+)$. In this paper we show that a linear operator T preserves the rank of matrices over the nonnegative integers if and only if T is a (U, V)­operator. We also obtain other characterizations of the linear operator that preserves rank of matrices over the nonnegative integers.

• Journal of Microbiology and Biotechnology
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• 제14권5호
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• pp.891-900
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• 2004

UDP-N-Acetylglucosamine(GlcNAc):$\beta$1,4-D-mannoside$\beta$-l ,4N-acetylglucosaminyltransferase-III (GnT-III) and UDP-N-GlcNAc:$\alpha$-6-D-mannosid$\beta$-1,6N-acetylglucosaminyltransferase-V(GnT - V) activities were determined in human hepatoma cell lines and metastatic colon cancer cells, and their activities were compared with those of normal liver cells and fetal hepatocytes. GnT-III activities were higher than those of GnT-V in hepatic carcinoma cells. When the two enzyme activities were assayed in highly metastatic colon cancer cells, GnT - V activities were much higher than those of GnT-III. When GlcN, GlcN-biant-PA and UDP-GlcNAc were used as substrates, the enzymes displayed different kinetic properties between hepatic and colon cancer cells, depending on their metastatic potentials. Normal cells of two origins had characteristically very low levels of GnT-III and -V activities, whereas hepatoma and colon cancer cells contained high levels of activities. These data were supported by RT-PCR and Northern blot analyses, showing that the expression of GnT-III and -V mRNAs were increased in proportion to the enzymatic activities. The increased GnT-III, md -V activities were also correlated with increased glycosylation of the cellular glycoproteins in hepatoma and colon cancer cells, as examined by lectin blotting analysis by using wheat germ glutinin (WGA), erythroagglutinating phytohemagglutinin (E-PHA), leukoagglutinating phytohemagglutinin (L-PHA), and concanavalin A (Con A). Treatment with retinoic acid, a differentiation agent, resulted in decreases of both GnT-III and -V activities of HepG2 and HepG3 cells. In colon carcinoma cells, however, treatment with retinoic acid resulted in a reduction of GnT-V activity, but not with GnT-III activity. Although the mechanism underlying the induction of these mzymes is unclear, oligosaccharides in many glycoproteins have been observed of cancer cells.

• 전기학회논문지P
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• 제57권3호
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• pp.275-278
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• 2008

It has been issued that the necessity of Live line work for 765kV vertical double circuit six bundle conductors transmission line when the characteristics of transmission line, the composition of T/L and near the T/L circumstances etc. Others are considered. The Barehand method of UHV T/L is extremely dangerous work and especially it is directly related with lineman life so it is very dangerous. It should be performed several technology developments for live-line work on the UHV T/L, that should be considered such as the electrical influence on workers near the T/L, development of live-line facilities, guarantee of safety, the technical rules of live-line work, the safe method of live-line work and etc. In order to maintain the 765kV transmission lines safely by barehand work, first of all, we should know the analysis of electrical safety level test in live-line work at 765kV vertical double circuit six bundle conductors on the suspension string tower type.

• 대한수학회지
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• 제38권1호
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• pp.177-191
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• 2001

We consider a linear differential game described by the delay-differential equation in a Hilbert space H; (※Equations, See Full-text) U and V are Hilbert spaces, and B(t) and C(t) are families of bounded operators on U and V to H, respectively. A(sub)0 generates an analytic semigroup T(t) = e(sup)tA(sub)0 in H. The control variables g, and u and v are supposed to be restricted in the norm bounded sets (※Equations, See Full-text). For given x(sup)0 ∈ H and a given time t > 0, we study $\xi$-approximate controllability to determine x($.$) for a given g and v($.$) such that the corresponding solution x(t) satisfies ∥x(t) - x(sup)0∥ $\leq$ $\xi$($\xi$ > 0 : a given error).

• Korean Journal of Mathematics
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• 제18권1호
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• pp.37-43
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• 2010

Let D be an integral domain, X be an indeterminate over D, and $N_v=\{f{\in}D[X]{\mid}(A_f)_v=D\}$. In this paper, we introduce the concept of t-locally divided domains, and we then prove that $D[X]_{N_v}$ is a locally divided domain if and only if D is a t-locally divided UMT-domain, if and only if D[X] is a t-locally divided domain.

• 대한수학회지
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• 제45권5호
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• pp.1405-1416
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• 2008

Let D be an integral domain, X an indeterminate over D, $N_v = \{f{\in}D[X]|(A_f)_v=D\}.$. Among other things, we introduce the concept of t-locally PVDs and prove that $D[X]N_v$ is a locally PVD if and only if D is a t-locally PVD and a UMT-domain, if and only if D[X] is a t-locally PVD, if and only if each overring of $D[X]N_v$ is a locally PVD.

• Korean Journal of Radiology
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• 제22권8호
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• pp.1352-1368
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• 2021

Objective: For an accurate dynamic contrast-enhanced (DCE) MRI analysis, exact baseline T1 mapping is critical. The purpose of this study was to compare the pharmacokinetic parameters of DCE MRI using synthetic MRI with those using fixed baseline T1 values. Materials and Methods: This retrospective study included 102 patients who underwent both DCE and synthetic brain MRI. Two methods were set for the baseline T1: one using the fixed value and the other using the T1 map from synthetic MRI. The volume transfer constant (K^trans), volume of the vascular plasma space (v_p), and the volume of the extravascular extracellular space (v_e) were compared between the two methods. The interclass correlation coefficients and the Bland-Altman method were used to assess the reliability. Results: In normal-appearing frontal white matter (WM), the mean values of K^trans, v_e, and v_p were significantly higher in the fixed value method than in the T1 map method. In the normal-appearing occipital WM, the mean values of v_e and v_p were significantly higher in the fixed value method. In the putamen and head of the caudate nucleus, the mean values of K^trans, v_e, and v_p were significantly lower in the fixed value method. In addition, the T1 map method showed comparable interobserver agreements with the fixed baseline T1 value method. Conclusion: The T1 map method using synthetic MRI may be useful for reflecting individual differences and reliable measurements in clinical applications of DCE MRI.

• 대한수학회지
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• 제41권5호
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• pp.773-793
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• 2004

We consider a system of particles with locations { $X_{i}$ $^{n}$ (t):t$\geq$0,i＝1,…,n} in $R^{d}$ , time-varying weights { $A_{i}$ $^{n}$ (t) : t $\geq$0,i ＝ 1,…,n} and weighted empirical measure processes $V^{n}$ (t)＝1/n$\Sigma$$_{i=1}$$^{n}$ $A_{i}$ $^{n}$ (t)$\delta$ $X_{i}$ $^{n}$ (t), where $\delta$$_{x}$ is the Dirac measure. It is known that there exists the limit of { $V_{n}$ } in the week* topology on M( $R^{d}$ ) under suitable conditions. If { $X_{i}$ $^{n}$ , $A_{i}$ $^{n}$ , $V^{n}$ } satisfies some diffusion equations, applying Ito formula, we prove a central limit type theorem for the empirical process { $V^{n}$ }, i.e., we consider the convergence of the processes η$_{t}$ $^{n}$ ≡ n( $V^{n}$ -V). Besides, we study a characterization of its limit.t.