灰色动态模型及其在人口预测中的应用

一个国家人口的数量直接影响着其经济、社会的发展和资源的利用 ,中国是世界上人口的第一大国 ,人口问题一直是制约中国发展的第一因素 .本文应用灰色系统等维灰数递补动态预测模型 ,对中国未来5 0年的人口数量进行了动态预测 ,通过检验表明 ,该模型合理、方法简便可行、结果符合实际 ,为中国经济和社会发展的决策和研究提供了科学依据  

分形插值曲面理论及其应用

本文叙述了分形曲面的生成原理，给出了分形插值曲面的计算公式，证明了分形插值曲面迭代函数系唯一性定理，导出了分形插值曲面的维数定理，并应用实际数据进行了分形插值曲面的实例研究·  

太阳黑子数时间序列的分形研究及预测

本文应用非线性动力系统理论分析了１８９１年１月至１９９６年１２月间太阳黑子月平均数变化的动力行为及其可预测性·计算了它的分形维数（Ｄ＝３３±０２）·确定了预测的嵌入维数［２×Ｄ＋１］＝７；计算了Ｌｙａｐｕｎｏｖ指数（λ１＝０８６３），揭示了该系统的混沌特性；并计算了Ｋｏｌｍｏｇｏｒｏｖ熵（Ｋ＝００２６０），用以从理论上分析这组数据可预报的时间尺度·最后根据分析的结果，从采样数据中截取一段数据进行了试验性的预测  

Integration and approximation in arbitrary dimensions

We study multivariate integration and approximation for various classes of functions of d variables with arbitrary d. We consider algorithms that use function evaluations as the information about the function. We are mainly interested in verifying when integration and approximation are tractable and strongly tractable. Tractability means that the minimal number of function evaluations needed to reduce the initial error by a factor of ɛ is bounded by C(d)ɛ^−p for some exponent p independent of d and some function C(d). Strong tractability means that C(d) can be made independent of d. The ‐exponents of tractability and strong tractability are defined as the smallest powers of ɛ{^-1} in these bounds. We prove that integration is strongly tractable for some weighted Korobov and Sobolev spaces as well as for the Hilbert space whose reproducing kernel corresponds to the covariance function of the isotropic Wiener measure. We obtain bounds on the ‐exponents, and for some cases we find their exact values. For some weighted Korobov and Sobolev spaces, the strong ‐exponent is the same as the ‐exponent for d=1, whereas for the third space it is 2. For approximation we also consider algorithms that use general evaluations given by arbitrary continuous linear functionals as the information about the function. Our main result is that the ‐exponents are the same for general and function evaluations. This holds under the assumption that the orthonormal eigenfunctions of the covariance operator have uniformly bounded L∞ norms. This assumption holds for spaces with shift-invariant kernels. Examples of such spaces include weighted Korobov spaces. For a space with non‐shift‐invariant kernel, we construct the corresponding space with shift-invariant kernel and show that integration and approximation for the non-shift-invariant kernel are no harder than the corresponding problems with the shift-invariant kernel. If we apply this construction to a weighted Sobolev space, whose kernel is non-shift-invariant, then we obtain the corresponding Korobov space. This enables us to derive the results for weighted Sobolev spaces. This revised version was published online in June 2006 with corrections to the Cover Date.  

关于自相似集的Hausdorff测度

得到了 Ｈａｕｓｄｏｒｆｆ容度与 Ｈａｕｓｄｏｒｆｆ测度相等的集的充分必要条件．对于满足开集条件的自相似集，验证了它的Ｈａｕｓｄｏｒｆｆ容度与Ｈａｕｓｄｏｒｆ测度相等并给出了它的Ｈａｕｓｄｏｒｆｆ测度的一个便于应用的公式．作为例子，给出了均匀康托集的Ｈａｕｓｄｏｒｆｆ测度的一种新的计算方法，对于Ｋｏｃｈ曲线的Ｈａｕｓｄｏｒｆｆ测度的上限也作了讨论．  

非交换凝聚环上的FP-自内射维数

本文引进了W~(n)-模,对具有有限FP-自内射维数的非交换凝聚环作了刻划.所得结果推广了Stentr(?)m和Bass等人的工作.最后给出了这些结果在扩张闭模范畴中的应用.  

三分Cantor集自乘积的Hausdorff测度的估计

本文证明了三分Cantor集C自乘积集C×C的Hausdorff测度,满足1≤H~((log_3)~4)(C×C)≤1.502879.  

Hochschild cohomology of truncated basic cycle

Dimensions of the Hochschild cohomology groups of a truncated algebra of a basic cycle are explicitly given. Project supported by the State Education Commission of China, the Chinese Academy of Sciences and the National Natural Science Foundation of China.  

INERTIAL FRACTAL SETS FOR DISSIPATIVE ZAKHAROV SYSTEM

0.IntroductionZakharoviz]hasprovedthatthepropagationofLangmuirwaveinplasmascanbedescribedbythefollowingsystemofcoupledequationsA~Zn,,~a(n IEI')=0,lEt BE~nE=0,E:R.xK-- C,n:R.xRt-- R.Itdescribesthenonlinearunstablestateofstronglyturbulentplasmas.TheparameterAisproportionaltotheionacousticspeed.Recently,Flaha.tll]hasstudiedthefollowingdissipativeZakharovsystemA--'n,, abet--a(n IEI')=f,lEt BE~nE i7E=g;or>0,7>0,andprovedtheexistenceofboundedabsorbingsetsinspaceE2,EIseparately.Namely,t…  

任意维数的强阻尼非线性波动方程（Ⅰ）—初边值问题

本文研究任意维数的强阻非线性波动方程ｕｔｔ－ａΔｕｔ－Δｕ＝ｆ（ｕ）具第一类齐边界条件的初值问题，设ｆ∈Ｃ＾１，ｆ＾１（ｕ）上方有界，且当ｎ≥４时存在常数Ａ，Ｂ和ｐ，使｜ｆ＾１（ｕ）｜≤Ａ｜ｕ｜＾ｐ＋Ｂ，其中０＜ｐ≤４／（ｎ－４）（ｎ＞４）：０＜ｐ＜∞（ｎ＝４），得到唯一整体强解，从而改进和推广了已知结果。