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1.
本文在研究了网络安全的国内外有关情况后对网络安全技术进行了探讨 ,介绍了一种简单而实用的网络安全产品 ,添补了这方面的空白 ,而且本文介绍的产品已经应用到了许多部门 ,为网络安全做出了贡献  相似文献   

2.
标准体系的使用期的模型与分析   总被引:1,自引:1,他引:0  
本文提出了关于标准体系使用期的两个模型。首先定义了标准使用期,然后讨论了模型的合理性。通过模型讨论了标准使用期的性质,给出了数值示例。提出了需进一步研究的问题。  相似文献   

3.
在学习了反比例函数后,老师带大家总结了两个点及函数图像的对称性.对于两个一次函数对称的情况,我自己进行了探索,发现了  相似文献   

4.
一种积分数据的函数重构及其误差估计   总被引:1,自引:0,他引:1  
本文考虑了一种基于函数积分平均值的函数重构方法,在定义了一个插值算子之后建立了误差估计.从理论分析结果可以看出这种方法得到的解是适定的,因此我们不需要选择正则化参数,这样就简化了算法,而且最后一系列的数值结果很好的验证了这种方法的有效性.  相似文献   

5.
提出了一类Chen-like系统,研究了该系统奇点稳定性、混沌等动力学性态.讨论了Chen-like系中参数与阶数对系统混沌性态的影响,并给出了Chem-like系统出现混沌性态的阶次范围.与分数阶Chen系统相比,系统出现混沌性态的阶次范围增大了.根据分数阶系统稳定性理论及线性反馈控制,对系统进行了混沌控制,得出了混沌系统在平衡点处的稳定性条件.数值模拟验证了理论分析的正确性.  相似文献   

6.
杨合俊 《大学数学》2014,(2):112-115
指出了一些微积分教辅书中一类极值问题的解答错误,分析了产生错误的原因,仔细研究了变量之间的关系,从而给出了正确的答案.  相似文献   

7.
揭丹 《数学杂志》2008,28(2):183-186
本文研究了对称阵的最小多项式的存在唯一性,利用对称阵的正交分解的基本思想,获得了对称阵的最小多项式的具体表示形式,改进了Hamilton-Caylay定理.并且给出了对称阵最小多项式的几个应用.  相似文献   

8.
本文研究了R_0代数上有关态算子的问题.利用MV-代数上内态的引入方法引入了态算子,定义了态R_0代数,它是R_0代数的一般化.给出了一些非平凡态R_0代数的例子并讨论了态R_0代数的一些基本性质.在此基础上给出了态滤子和态局部R_0代数的概念,并利用态滤子刻画了态局部R_0代数.推广了局部R_0代数的相关理论.  相似文献   

9.
高阶数值微分的积分方法   总被引:1,自引:1,他引:0  
本文研究了高阶数值微分问题,利用Groetsch的思想,获得了可以稳定逼近近似已知函数的任意阶导数的积分方法,并在一定条件下,给出了收敛率.给出了二阶、三阶和四阶数值微分问题的数值实验,实验结果表明了方法的有效性.  相似文献   

10.
模糊幂格     
彭家寅 《数学杂志》2008,28(1):45-49
本文研究了格向其模糊幂集上提升的问题.利用模糊集理论,引入了模糊幂格的概念,获得了模糊幂格及其模糊理想的若干基本性质,推广了格的结果.  相似文献   

11.
科学合理的规模结构不仅是实现规模经济的基本条件,而且是提高经济效益、降低交易成本、获得较高的企业竞争力的重要保证.基于规模理论,从生产规模、资本规模、市场规模以及效益规模四大因素入手,提出了一套基于规模的企业竞争力评价指标体系,运用蜘蛛图法建立了基于规模的企业竞争力评价模型,并结合具体的数据分析说明了企业竞争力的大小强弱.此种方法具有直观形象、定量化、可操作性强的特点.  相似文献   

12.
DP-coloring of a simple graph is a generalization of list coloring, and also a generalization of signed coloring of signed graphs. It is known that for each k{3,4,5,6}, every planar graph without Ck is 4-choosable. Furthermore, Jin et al. (2016) showed that for each k{3,4,5,6}, every signed planar graph without Ck is signed 4-choosable. In this paper, we show that for each k{3,4,5,6}, every planar graph without Ck is 4-DP-colorable, which is an extension of the above results.  相似文献   

13.
两类带有确定潜伏期的SEIS传染病模型的分析   总被引:2,自引:0,他引:2  
通过研究两类带有确定潜伏期的SEIS传染病模型,发现对种群的常数输入和指数输入会使疾病的传播过程产生本质的差异.对于带有常数输入的情形,找到了地方病平衡点存在及局部渐近稳定的阈值,证明了地方病平衡点存在时一定局部渐近稳定,并且疾病一致持续存在.对于带有指数输入的情形,发现地方病平衡点当潜伏期充分小时是局部渐近稳定的,当潜伏期充分大时是不稳定的.  相似文献   

14.
We discuss dimension theory in the class of all topological groups. For locally compact topological groups there are many classical results in the literature. Dimension theory for non-locally compact topological groups is mysterious. It is for example unknown whether every connected (hence at least 1-dimensional) Polish group contains a homeomorphic copy of [0,1]. And it is unknown whether there is a homogeneous metrizable compact space the homeomorphism group of which is 2-dimensional. Other classical open problems are the following ones. Let G be a topological group with a countable network. Does it follow that dimG=indG=IndG? The same question if X is a compact coset space. We also do not know whether the inequality dim(G×H)dimG+dimH holds for arbitrary topological groups G and H which are subgroups of σ-compact topological groups. The aim of this paper is to discuss such and related problems. But we do not attempt to survey the literature.  相似文献   

15.
The weight w(e) of an edge e in a normal plane map (NPM) is the degree-sum of its end-vertices. An edge e=uv is of type (i,j) if d(u)i and d(v)j. In 1940, Lebesgue proved that every NPM has an edge of one of the types (3,11), (4,7), or (5,6), where 7 and 6 are best possible. In 1955, Kotzig proved that every 3-connected planar graph has an edge e with w(e)13, which bound is sharp. Borodin (1989), answering Erd?s’ question, proved that every NPM has either a (3,10)-edge, or (4,7)-edge, or (5,6)-edge.A vertex is simplicial if it is completely surrounded by 3-faces. In 2010, Ferencová and Madaras conjectured (in different terms) that every 3-polytope without simplicial 3-vertices has an edge e with w(e)12. Recently, we confirmed this conjecture by proving that every NPM has either a simplicial 3-vertex adjacent to a vertex of degree at most 10, or an edge of types (3,9), (4,7), or (5,6).By a k(?)-vertex we mean a k-vertex incident with precisely ? triangular faces. The purpose of our paper is to prove that every NPM has an edge of one of the following types: (3(3),10), (3(2),9), (3(1),7), (4(4),7), (4(3),6), (5(5),6), or (5,5), where all bounds are best possible. In particular, this implies that the bounds in (3,10), (4,7), and (5,6) can be attained only at NPMs having a simplicial 3-, 4-, or 5-vertex, respectively.  相似文献   

16.
A star edge-coloring of a graph G is a proper edge coloring such that every 2-colored connected subgraph of G is a path of length at most 3. For a graph G, let the list star chromatic index of G, chs(G), be the minimum k such that for any k-uniform list assignment L for the set of edges, G has a star edge-coloring from L. Dvo?ák et al. (2013) asked whether the list star chromatic index of every subcubic graph is at most 7. In Kerdjoudj et al. (2017) we proved that it is at most 8. In this paper we consider graphs with any maximum degree, we proved that if the maximum average degree of a graph G is less than 145 (resp. 3), then chs(G)2Δ(G)+2 (resp. chs(G)2Δ(G)+3).  相似文献   

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整环R称为ω-凝聚整环,是指R的每个有限型理想是有限表现型的.本文证明了ω-凝聚整环是v-凝聚整环,且若(RDTF,M)是Milnor方图,则在Ⅰ型情形,R是ω-凝聚整环当且仅当D和T都是ω-整环,且T_M是赋值环;对于Ⅱ-型情形,R是ω-凝聚整环当且仅当D是域,[F:D]<∞,M是R的有限型理想,T是ω-凝聚整环,且R_M是凝聚整环.  相似文献   

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