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Some Cycle and Star Related Nordhaus-Gaddum Type Relations on Strong Efficient Dominating Sets

  • Murugan, Karthikeyan
    • Kyungpook Mathematical Journal
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    • v.59 no.3
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    • pp.363-375
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    • 2019
  • Let G = (V, E) be a simple graph with p vertices and q edges. A subset S of V (G) is called a strong (weak) efficient dominating set of G if for every $v{\in}V(G)$ we have ${\mid}N_s[v]{\cap}S{\mid}=1$ (resp. ${\mid}N_w[v]{\cap}S{\mid}=1$), where $N_s(v)=\{u{\in}V(G):uv{\in}E(G),\;deg(u){\geq}deg(v)\}$. The minimum cardinality of a strong (weak) efficient dominating set of G is called the strong (weak) efficient domination number of G and is denoted by ${\gamma}_{se}(G)$ (${\gamma}_{we}(G)$). A graph G is strong efficient if there exists a strong efficient dominating set of G. In this paper, some cycle and star related Nordhaus-Gaddum type relations on strong efficient dominating sets and the number of strong efficient dominating sets are studied.

SOME PROPERTIES OF THE STRONG CHAIN RECURRENT SET

  • Fakhari, Abbas;Ghane, Fatomeh Helen;Sarizadeh, Aliasghar
    • Communications of the Korean Mathematical Society
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    • v.25 no.1
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    • pp.97-104
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    • 2010
  • The article is devoted to exhibit some general properties of strong chain recurrent set and strong chain transitive components for a continuous map f on a compact metric space X. We investigate the relation between the weak shadowing property and strong chain transitivity. It is shown that a continuous map f from a compact metric space X onto itself with the average shadowing property is strong chain transitive.

SOME RESULTS ON CONDITIONALLY UNIFORMLY STRONG MIXING SEQUENCES OF RANDOM VARIABLES

  • Yuan, De-Mei;Hu, Xue-Mei;Tao, Bao
    • Journal of the Korean Mathematical Society
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    • v.51 no.3
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    • pp.609-633
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    • 2014
  • From the ordinary notion of uniformly strong mixing for a sequence of random variables, a new concept called conditionally uniformly strong mixing is proposed and the relation between uniformly strong mixing and conditionally uniformly strong mixing is answered by examples, that is, uniformly strong mixing neither implies nor is implied by conditionally uniformly strong mixing. A couple of equivalent definitions and some of basic properties of conditionally uniformly strong mixing random variables are derived, and several conditional covariance inequalities are obtained. By means of these properties and conditional covariance inequalities, a conditional central limit theorem stated in terms of conditional characteristic functions is established, which is a conditional version of the earlier result under the non-conditional case.

Spatial Distribution of Strong Winds on the Korean Peninsula during the Non-Typhoon affecting Period - Observations and Strong Wind Special Report- (한반도 비태풍시기 강풍의 공간적 분포 특징 - 관측 자료와 강풍특보 자료 -)

  • Na, Hana;Jung, Woo-Sik
    • Journal of Environmental Science International
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    • v.30 no.9
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    • pp.763-777
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    • 2021
  • The spatial characteristics of typhoon-class strong wind during the non-typhoon period were analyzed using, a cluster analysis of the observational data and of special strong wind advisories and, warnings issued by the Korean Meteorological Administration. On the Korean Peninsula, strong winds during non-typhoon periods showed a wide variety of spatial characteristics. In particular, the cluster analysis showed that strong winds could be classified into six clusters on the Korean Peninsula, and that the spatial distribution, occurrence rate of strong winds, and strong wind speed in each cluster were complex and diverse. In addition, our analysis of the frequency of issuance of special strong wind warnings showed a significant difference in the average frequency of strong wind warnings issued in metropolitan cities, with relatively high numbers of warnings issued in Gyeongsangbuk-do and, Jeollanam-do, and low numbers of warning issued inland and in other metropolitan cities. As a result of the changing trend in warnings issued from 2004 to 2019, Ulsan and Busan can be interpreted as having a relatively high number of warnings; the frequency of strong wind warnings issuances and strong wind occurrences in these cities is increasing rapidly. Based on the results of this study, it is necessary to identify areas with similar strong wind characteristics and consider specific regional standards in terms of disaster prevention.

THE STRONG PERRON AND MCSHANE INTEGRALS

  • Park, Jae Myung;Kim, Joo Bong;Lee, Woo Youl
    • Journal of the Chungcheong Mathematical Society
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    • v.13 no.1
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    • pp.21-26
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    • 2000
  • In this paper, we define the strong Perron integral and study the relationship between the integrals of strong Perron and McShane.

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Manufacturing Process and Component Analysis of Seawater Salt Using Seaweeds (해조류를 이용한 해수소금 제조기법 및 성분분석)

  • Lee, Seung-Won;Kim, Hyeon-Ju;Moon, Deok-Soo;Jung, Dong-Ho;Choi, Hark-Sun
    • Journal of Ocean Engineering and Technology
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    • v.21 no.4
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    • pp.61-65
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    • 2007
  • In this research, we have developed a manufacturing process for seawater salt by horizontal spray drying technique using the deep ocean water and seaweed(sea tangle). Deep ocean water, strong acidic electrolyzed water and strong alkaline electrolyzed water were used as extraction solvent of seaweed. Sodium content in seaweed extract solution by strong alkaline electrolyzed water was 1.63(mg/g), which was 3.5 times lower than of seaweed extract by strong acidic electrolyzed water. Major mineral content(Na, K, Ca) in seawater salt by deep ocean water were higher than strong acidic electrolyzed water and strong alkaline electrolyzed water. On the contrary, Mg contents in seawater salt by deep ocean water were lower than strong acidic electrolyzed water and strong alkaline electrolyzed water. Based on the results of seawater salt production using seaweed, it is possible to make law-salt efficiently.

ON STRONG REVERSIBLE RINGS AND THEIR EXTENSIONS

  • Baser, Muhittin;Kwak, Tai Keun
    • Korean Journal of Mathematics
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    • v.18 no.2
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    • pp.119-132
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    • 2010
  • P. M. Cohn called a ring R reversible if whenever ab = 0, then ba = 0 for $a,b{\in}R$. In this paper, we study an extension of a reversible ring with its endomorphism. An endomorphism ${\alpha}$ of a ring R is called strong right (resp., left) reversible if whenever $a{\alpha}(b)=0$ (resp., ${\alpha}(a)b=0$) for $a,b{\in}R$, ba = 0. A ring R is called strong right (resp., left) ${\alpha}$-reversible if there exists a strong right (resp., left) reversible endomorphism ${\alpha}$ of R, and the ring R is called strong ${\alpha}$-reversible if R is both strong left and right ${\alpha}$-reversible. We investigate characterizations of strong ${\alpha}$-reversible rings and their related properties including extensions. In particular, we show that every semiprime and strong ${\alpha}$-reversible ring is ${\alpha}$-rigid and that for an ${\alpha}$-skew Armendariz ring R, the ring R is reversible and strong ${\alpha}$-reversible if and only if the skew polynomial ring $R[x;{\alpha}]$ of R is reversible.