Logistic模型的预测应用两例

利用灰色建模法对Logistic模型中的参数进行估计,并将其应用于温州人口以及温州民用汽车拥有量的预测上取得了良好的预测效果.     

Effective Information for Offline Stochastic Feedback and Optimal Control of Dynamic Systems

The impact of uncertain future events on decision making in a stochastic environment is modeled in this paper. Such modeling is presented for both feedback and optimal control problems. This research overcomes the difficulties of forecasting that arise when considering future information. In this paper, we seek to find the minimum amount of information (effective information) necessary to evaluating system performance offline or to optimally control a system. The existence of effective information is proved and a methodology for determining it is developed. It is also shown that ignoring information beyond the planning horizon leads to significant performance loss and may even lead to violating the constraints of a control problem.     

Effect of aniline formaldehyde resin on the conjugation length and structure of doped polyaniline: Spectral studies

A DBSA (n‐dodecylbenzene sulfate)‐complexed aniline formaldehyde [AF(DBSA)_1.0] was successfully synthesized with excess aniline (compared with formaldehyde) in the presence of n‐dodecylbenzene sulfonic acid (HDBSA), which was complexed with aniline monomer before polymerization. The resin was carefully characterized with ¹H and ¹³C NMR, electron spectroscopy for chemical analysis, and Fourier transform infrared and was demonstrated to be a polymer in which anilines were all complexed with HDBSA and became anilinium salts. A drastic decrease of the maximum absorption wavelength (ultraviolet–visible spectra) of DBSA‐doped polyaniline [PANI(DBSA)_0.5] was found when AF(DBSA)_1.0 was mixed, and this resulted from the reduced conjugation length. A similar effect on PANI(DBSA)_0.5 was found when free HDBSAs were mixed with PANI(DBSA)_0.5. Visual inspection with an optical microscope revealed that PANI(DBSA)_0.5/AF(DBSA)_1.0 gave uniform morphologies in various compositions, showing possible miscibility for this system. X‐ray diffraction patterns of PANI(DBSA)_0.5/AF(DBSA)_1.0 showed that the layered structure of PANI(DBSA)_0.5 was still present but became shorter in the polyblend because of the presence of AF(DBSA)_1.0. Solid‐state ¹³C NMR spectra revealed that the reduced conjugation length was derived from the interaction of alkyl groups between HDBSA, complexed DBSA, and dopant DBSAs. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3116–3125, 2005     

Random waypoint model in n-dimensional space

The random waypoint model (RWP) is one of the most widely used mobility models in performance analysis of mobile wireless networks. In this paper we extend the previous work by deriving an analytical formula for the stationary distribution of a node moving according to a RWP model in n-dimensional space.     

飞机空中加油问题的研究

讨论了飞机的空中加油问题,通过比较不同方案下主机的最大作战半径,找到了辅机给主机空中加油的最佳方案,分析了存在多个基地时各基地的位置及辅机在各基地的数量,研究了二维坐标下主机的最佳飞行路径,给出了解决问题的办法.整个思路由浅入深,通过考虑辅机数目n分别为1,2,3,4的特殊情况进而探讨一般的规律,包括辅机在基地无加油时间和有加油时间以及主机在空中盘旋等不同假设条件下的复杂情况,并将统计出的数据列表对比,获得了更直观的认识.在最后进行了展望,希望结合实际中的飞机空中加油问题综合考虑风力、风向等随机因素的影响,拓展到3维空间的更复杂模型中,使飞机的空间加油问题变得更有实际意义.     

高雷诺数下降液膜流动换热分析

本文分析了降液膜高雷诺数区域换热系数随液膜长度变化趋势,引出临界长度的概念。在较高雷诺数的湍流区,回流区的存在以及表面波的影响能有效地减少局部薄膜厚度并增加对流换热,流速的增加进一步强化换热,增加降膜整体传热系数。在高雷诺数区域,厚度形成的热阻超过回流的增强作用,而使换热削弱。液膜小于临界长度L换热系数随长度增长而增加,大于L换热系数随液膜增长而减小。     

Determination of the inelastic mean free paths (IMFPs) in Ti by elastic peak electron spectroscopy (EPES): Effect of impurities and surface excitations

Surface excitations are important in surface sensitive electron spectroscopes, especially in elastic peak electron spectroscopy (EPES) since they may distort quantitative information. This phenomenon is more pronounced at low electron energy and glancing emission angles and should be appropriately corrected.In the present work we investigate quantitatively the role of contaminations, density and surface excitations on electron inelastic mean free paths (IMFPs) in Ti determined by elastic peak electron spectroscopy (EPES) using Cu standard. In the Monte Carlo algorithm the new NIST 3.1 database of electron elastic scattering cross sections was applied. It has been also shown that accounting for surface excitations, as well as for appropriate input parameters (surface composition, density, hydrogen) in the EPES method, is important for accuracy of evaluated IMFPs. Due to high reactivity of Ti, the IMFPs for contaminated Ti may be of interest. The authors indicate the magnitude of various corrections on the IMFPs derived by EPES.     

Application of a heuristic search technique for the improvement of spray zones cooling conditions in continuously cast steel billets

The process of casting occupies an important place in the metallurgical industry, and the entire world of the metal user. In the past, the ingot casting–rolling (slabbing, blooming, or billeting) process was commonly used. The continuous casting process has largely replaced this earlier method because of the inherent advantages of energy savings, enhanced productivity, higher yield and reduced costs. However, continuous casting process is not without of its problems. Considerable effort has been made by many researches to establish adequate design, operation and maintenance of continuous casting machine to ensure metallurgical quality of the final product. One of the most severe defects in continuous casting products is concerned with the cracks provoked by improper design of the spray cooling system. The aim of this work is to develop a two dimensional heat transfer model based on the finite difference method in order to calculate the strand temperatures and the solid shell profile along the machine. An Artificial Intelligence heuristic search procedure interacts with the numerical model to determine the improved cooling conditions for the sprays zones of a real continuous caster for the production of quality billets.     

图T1,1,m与Q(3,n)中有路因子的充分必要条件及T1,1,m的匹配等价类

如果一个图的匹配多项式可以被一个路的匹配多项式整除,我们就称此路是该图的一个路因子,路因子在刻画图的匹配等价类,研究匹配唯一性方面有很重要的作用.本文得到了图T1,1.m与图Q(3,n)中有路因子的充分必要条件.