• Title/Summary/Keyword: Weak Point

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A FIXED POINT THEOREM FOR ASYMPTOTICALLY C-CONTRACTIVE MAPPINGS

  • Park, Jong An
    • Korean Journal of Mathematics
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    • v.11 no.2
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    • pp.111-115
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    • 2003
  • Under some asymptotical conditions we obtain a fixed point theorem for a mapping(not necessarily nonexpansive) from an unbounded closed convex subset of a reflexive Banach space into itself. Also we give an example for applying it.

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Weak Convergence of Processes Occurring in Statistical Mechanics

  • Jeon, Jong-Woo
    • Journal of the Korean Statistical Society
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    • v.12 no.1
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    • pp.10-17
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    • 1983
  • Let $X^{(n)}_j, j=1,2,\cdots,n, n=1,2,\cdots$ be a triangular array of random variables which arise naturally in a study of ferromagnetism in statistical mechanics. This paper presents weak convergence of random function $W_n(t)$, an appropriately normalized partial sum process based on $S^{(n)}_n = X^{(n)}_i+\cdot+X^{(n)}_n$. The limiting process W(t) is shown to be Gaussian when weak dependence exists. At the critical point where the change form weak to strong dependence takes place, W(t) turns out to be non-Gaussian. Our results are direct extensions of work by Ellis and Newmam (1978). An example is considered and the relation of these results to critical phenomena is briefly explained.

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A class of CUSUM tests using empirical distributions for tail changes in weakly dependent processes

  • Kim, JunHyeong;Hwang, Eunju
    • Communications for Statistical Applications and Methods
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    • v.27 no.2
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    • pp.163-175
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    • 2020
  • We consider a wide class of general weakly-dependent processes, called ψ-weak dependence, which unify almost all weak dependence structures of interest found in statistics under natural conditions on process parameters, such as mixing, association, Bernoulli shifts, and Markovian sequences. For detecting the tail behavior of the weakly dependent processes, change point tests are developed by means of cumulative sum (CUSUM) statistics with the empirical distribution functions of sample extremes. The null limiting distribution is established as a Brownian bridge. Its proof is based on the ψ-weak dependence structure and the existence of the phantom distribution function of stationary weakly-dependent processes. A Monte-Carlo study is conducted to see the performance of sizes and powers of the CUSUM tests in GARCH(1, 1) models; in addition, real data applications are given with log-returns of financial data such as the Korean stock price index.

Conservation treatment of the sword with round pommel with a tri-ring excavated at Duckcheon-ri Tomb in Gyeongju (경주 덕천리 유적 수습 유물 보존처리-삼두환두대도를 중심으로)

  • Kim, Ji-Young;Seo, Jung-Eun;Ryu, Dong-Wan
    • 보존과학연구
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    • s.26
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    • pp.127-139
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    • 2005
  • We have conserved the sword with round pommel with a tri-ring which was excavated from No. 1 tomb of the Duckcheon-ri at the Gyeongju and requested from Jungang Research Center of the Cultural Heritage. When this artifact excavated, it was pressed flat state because of the influence of earth pressure and stuck to a gravel and soil laid scattered on the wooden coffin. If the artifacts is handled without plan, it can be damaged, therefore that sword was collected together with soil using the Polyurethane foam. After the artifact which had a weak specific and was collected using a this method can be safetly collected as below; First, we made the supporter of article ordered using a silicon and gypsum. The silicon can conserve the weak point of the artifact because it has a flexible and smooth properties and the gypsum can adhere closely to the artifact because it has a little expansion and shrinking but a hard and fluid characters. Consequently, gypsum is a good complement to the weak point of the silicon. Second, During a remove gauze and a reinforcing agent from the surface of a artifact which was reinforced using a acetone steam method. The acetone steam method can be supplement to a dangerous problem of acetonedircet method because this can be damaged in a surface of the artifact.

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Water Droplet Ejection Characteristics of a Wet Porous Point-Plate Airgap (다공성 수침-평판전극간의 수적 방출 특성)

  • Jung, Jae-Seung;Lee, Woo-Seok;Moon, Jae-Duk
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.10
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    • pp.2005-2010
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    • 2009
  • Water droplet ejection characteristics of a point-to-plate airgap, with a wet porous point as a corona electrode, has been investigated. And the water droplet traces, charge, mass and number were measured experimentally. More particles are observed with wet porous point than metal point because the corona-discharging wet porous point can eject a number of water droplets. The water droplets ejected from the positive-corona-discharging wet porous point showed very fine traces as compared with those from the negative-corona-discharging wet porous point. Moreover, the water droplets ejected from the AC-corona-discharging wet porous point showed granular-like larger traces. It was shown that the weak corona discharge can eject smaller water droplets with larger ratio of mass-to-charge than the intense corona discharge.

A NEW CLASS OF GENERALIZED CONVEX PROGRAMMING

  • YAN ZHAOXIANG;LI SHIZHENG
    • Journal of applied mathematics & informatics
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    • v.17 no.1_2_3
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    • pp.351-360
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    • 2005
  • This paper finds a new class of generalized convex function which satisfies the following properties: It's level set is $\eta$-convex set; Every feasible Kuhn-Tucker point is a global minimum; If Slater's constraint qualification holds, then every minimum point is Kuhn-Tucker point; Weak duality and strong duality hold between primal problem and it's Mond-Weir dual problem.

Nonparametric Discontinuity Point Estimation in Density or Density Derivatives

  • Huh, Jib
    • Journal of the Korean Statistical Society
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    • v.31 no.2
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    • pp.261-276
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    • 2002
  • Probability density or its derivatives may have a discontinuity/change point at an unknown location. We propose a method of estimating the location and the jump size of the discontinuity point based on kernel type density or density derivatives estimators with one-sided equivalent kernels. The rates of convergence of the proposed estimators are derived, and the finite-sample performances of the methods are illustrated by simulated examples.