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991.
992.
Weifan Wang Tingting Wu Xiaoxue Hu Yiqiao Wang 《Journal of Combinatorial Optimization》2018,35(3):980-996
Let G be a connected graph with \(n\ge 2\) vertices. Suppose that a fire breaks out at a vertex v of G. A firefighter starts to protect vertices. At each step, the firefighter protects two vertices not yet on fire. At the end of each step, the fire spreads to all the unprotected vertices that have a neighbour on fire. Let sn\(_2(v)\) denote the maximum number of vertices in G that the firefighter can save when a fire breaks out at vertex v. The 2-surviving rate \(\rho _2(G)\) of G is defined to be the real number \(\frac{1}{n^2} \sum _{v\in V(G)} \mathrm{sn}_2(v)\). Then it is obvious that \(0<\rho _2(G)<1\). The graph G is called 2-good if there is a constant \(c>0\) such that \(\rho _2(G)>c\). In this paper, we prove that every planar graph with \(n\ge 2\) vertices and without chordal 5-cycles is 2-good. 相似文献
993.
The least squares fit in a linear regression is always unique even when the design matrix has rank deficiency. In this paper, we extend this classic result to linearly constrained generalized lasso. It is shown that under a mild condition, the fit can be represented as a projection onto a polytope and, hence, is unique no matter whether design matrix X has full column rank or not. Furthermore, a formula for the degrees of freedom is derived to characterize the effective number of parameters. It directly yields an unbiased estimate of degrees of freedom, which can be incorporated in an information criterion for model selection. 相似文献
994.
Zixing Tang Baoyindureng Wu Lin Hu Manoucheher Zaker 《Journal of Combinatorial Optimization》2017,33(2):580-589
A coloring of a graph \(G=(V,E)\) is a partition \(\{V_1, V_2, \ldots , V_k\}\) of V into independent sets or color classes. A vertex \(v\in V_i\) is a Grundy vertex if it is adjacent to at least one vertex in each color class \(V_j\) for every \(j<i\). A coloring is a Grundy coloring if every vertex is a Grundy vertex, and the Grundy number \(\Gamma (G)\) of a graph G is the maximum number of colors in a Grundy coloring. We provide two new upper bounds on Grundy number of a graph and a stronger version of the well-known Nordhaus-Gaddum theorem. In addition, we give a new characterization for a \(\{P_{4}, C_4\}\)-free graph by supporting a conjecture of Zaker, which says that \(\Gamma (G)\ge \delta (G)+1\) for any \(C_4\)-free graph G. 相似文献
995.
Since the seminal paper of Ghirardato (1997), it is known that Fubini theorem for non additive measures can be available only for functions as “slice-comonotonic” in the framework of product algebra. Later, inspired by Ghirardato (1997), Chateauneuf and Lefort (2008) obtained some Fubini theorems for non additive measures in the framework of product σ-algebra. In this article, we study Fubini theorem for non additive measures in the framework of g-expectation. We give some different assumptions that provide Fubini theorem in the framework of g-expectation. 相似文献
996.
文章结合物流资源配置过程的复杂性特征,提出考虑服务质量与服务柔性的汽车零部件物流资源组合优化配置策略,该策略设计了以汽车零部件全供应链信息共享平台为依托的跨组织物流资源优化配置流程,并重点对资源优化配置过程中的关键问题进行了描述,建立以时间、空间、成本、质量和效率为目标的汽车零部件物流资源组合优化配置模型,并给出基于改进的进化多目标优化算法的求解过程,最后以某企业汽车零部件物流资源组合配置的实例验证了该流程、优化配置模型及求解方法的有效性与实用性. 相似文献
997.
998.
AbstractObjective: Existing literature on young adults’ e-cigarette and polysubstance use focused on college students. This study examined the differences between college and noncollege groups on prevalence and patterns of e-cigarette and other substance use using data from a national survey. Participants: Adults aged 18–24 from the 2013–2014 Population Assessment of Tobacco and Health Study (n?=?6,608). Methods: Independent sample t-tests and Chi-square tests were conducted to examine group differences. Results: Noncollege young adults had higher prevalence of cigarette, e-cigarette, and marijuana use; college students had higher prevalence of alcohol use. Among current e-cigarette users, college students had higher prevalence of polysubstance use of alcohol and marijuana. College students used e-cigarettes for socializing purposes more. Conclusions: Differences in prevalence and patterns of e-cigarette and other substance use between college and noncollege groups exist. Future interventions should target the social context of college life and reach out to noncollege young adults in workplaces. 相似文献
999.
X. L. Hu P. Castagliola A. A. Tang 《Journal of Statistical Computation and Simulation》2019,89(13):2468-2488
In practice, different practitioners will use different Phase I samples to estimate the process parameters, which will lead to different Phase II control chart's performance. Researches refer to this variability as between-practitioners-variability of control charts. Since between-practitioners-variability is important in the design of the CUSUM median chart with estimated process parameters, the standard deviation of average run length (SDARL) will be used to study its properties. It is shown that the CUSUM median chart requires a larger amount of Phase I samples to sufficiently reduce the variation in the in-control ARL of the CUSUM median chart. Considering the limitation of the amount of the Phase I samples, a bootstrap approach is also used here to adjust the control limits of the CUSUM median chart. Comparisons are made for the CUSUM and Shewhart median charts with estimated parameters when using the adjusted- and unadjusted control limits and some conclusions are made. 相似文献
1000.
改革开放以来,凉山彝族婚嫁彩礼持续走高,特别近10年来,婚嫁彩礼已经变异为“高额彩礼”。课题组自2018年至2022年,以凉山彝族“高额彩礼”为研究对象,探究“高额彩礼”的性质、形成的原因和带来的社会问题;我们认为 “高额彩礼”阻碍凉山社会经济与精神文明的发展,不利于社会和谐稳定,凉山急需进行一场彻底的移风易俗洗礼,使彩礼不再“高额”,让彝族青年走出“婚嫁漩涡”,形成崇尚文明新风、抵制陈规陋习的社会风气,助力脱贫致富奔小康。 相似文献