Quadratic optimal neural fuzzy control for synchronization of uncertain chaotic systems

This paper presents a novel quadratic optimal neural fuzzy control for synchronization of uncertain chaotic systems via H^∞ approach. In the proposed algorithm, a self-constructing neural fuzzy network (SCNFN) is developed with both structure and parameter learning phases, so that the number of fuzzy rules and network parameters can be adaptively determined. Based on the SCNFN, an uncertainty observer is first introduced to watch compound system uncertainties. Subsequently, an optimal NFN-based controller is designed to overcome the effects of unstructured uncertainty and approximation error by integrating the NFN identifier, linear optimal control and H^∞ approach as a whole. The adaptive tuning laws of network parameters are derived in the sense of quadratic stability technique and Lyapunov synthesis approach to ensure the network convergence and H^∞ synchronization performance. The merits of the proposed control scheme are not only that the conservative estimation of NFN approximation error bound is avoided but also that a suitable-sized neural structure is found to sufficiently approximate the system uncertainties. Simulation results are provided to verify the effectiveness and robustness of the proposed control method.     

路由协议测试的窗口黑盒模型和多通道的测试方法

路由协议测试中的效率和覆盖率亟待提高,原有通信协议测试理论将被测实现作为黑盒,使得大量可增强控制观察能力的手段无法利用,因此在路由协议测试中以窗口黑盒模型描述被测实现,在测试结构上实现了多通道测试方法,提高了测试效率和测试覆盖率,通过与被测模块交互的其它模块,增强了测试的控制观察能力,测试便的执行时间相比原有方式下降50％;消除或减小了以往不能测试的范围和内容,相应测试例个数增加3倍以上;为目前急需的大规模的路由器测试工作奠定了基础。     

Limitations of nonlinear discrete periodic control for disturbance attenuation and robust stabilization

This paper presents a performance analysis of nonlinear periodically time-varying discrete controllers acting upon a linear time-invariant discrete plant. Time-invariant controllers are distinguished from strictly periodically time-varying controllers. For a given nonlinear periodic controller, a time-invariant controller is constructed. Necessary and sufficient conditions are given under which the time-invariant controller gives strictly better control performance than the time-invariant controller from which it was obtained, for the attenuation of l_p exogenous disturbances and the robust stabilization of l_p unstructured perturbations, for all p[1,∞].     

A method of predicting the number of clusters using Rand's statistic

Distributional and asymptotic results on the moment of Rand's C_k statistic were derived by DuBien and Warde [1981. Some distributional results concerning a comparative statistic used in cluster analysis. ASA Proceedings of the Social Statistics Section, 309–313.]. Based on those results, a method to predict the number of clusters is suggested by applying various agglomerative clustering algorithms. In the procedure, the methods using different indexes are examined and compared based on the concept of agreement (or, disagreement) between clusterings generated by different clustering algorithms on the set of data. Our method having practical generality works better than the other methods and assigns statistical meaning to C_k values in determining the number of clusters from the comparison.     

炭黑填充导电丁腈橡胶研究

研究了用华光化工厂产导电炭黑填充丁腈橡胶的导电性规律。探讨了配方、加工工艺、混炼胶存放、胶料老化以及测试条件等诸多因素与导电性的关系。优选出了硬度７０左右的胶料，其体积电阻率为２．２２Ω·ｃｍ。     

雨型对东北黑土区坡耕地土壤侵蚀影响的试验研究

降雨雨型对土壤侵蚀过程有重要的影响,也是当前土壤侵蚀研究的热点之一。通过野外原位人工模拟降雨试验,设计了次降雨中平均降雨强度、总降雨量相同的4种不同降雨雨型(均匀型:降雨强度为60mm/h;峰值型:降雨强度分布为30-90-60mm/h;延迟型:降雨强度分布为60-30-90mm/h;减弱型:降雨强度分布为90-60-30mm/h),研究降雨雨型变化对东北黑土区坡耕地土壤侵蚀的影响。结果表明:各雨型条件下休闲坡耕地径流总量的大小顺序为延迟型>减弱性>均匀型>峰值型,而土壤侵蚀总量的大小顺序为减弱型>均匀型>延迟型>峰值型。延迟型雨型的坡面径流总量是其它雨型的1.02~1.45倍,减弱型降雨的侵蚀总量分别是均匀型、延迟型和峰值型的1.03、1.36和2.68倍。同一雨强在不同降雨雨型中出现的位置不同,其产生的坡面径流量和侵蚀量对坡面总径流量、总侵蚀量的贡献率也不同,分布在降雨雨型起始位置的雨强对坡面径流量的贡献率最小;除30mm/h降雨强度外,分布在降雨雨型起始位置的雨强对坡面侵蚀的贡献率最大。研究还发现,试验设计中减弱型降雨雨型与东北黑土区夏季主要侵蚀雨型特点类似,是造成东北黑土区坡耕地土壤侵蚀相对严重的主要雨型。     

有机溶剂在湿法磷酸脱色中的应用

为了研究有机溶剂在湿法磷酸脱色的效果,以黑色的湿法磷酸为原料,分别使用四氯化碳、氯仿、柴油对湿法磷酸进行预脱色,再用活性炭对预脱色后的酸进行脱色.实验结果表明,柴油的预脱色效果最明显;最佳脱色条件为：湿法浓磷酸和柴油的质量比为5∶1、萃取分离时间1 h,活性炭的用量为湿法磷酸质量的1.5%、活性炭脱色时的温度为60℃、脱色时间为30 min,采用目测法观察,湿法磷酸从黑色基本变成无色;湿法稀磷酸和柴油的质量比为13∶1、萃取分离时间为20 min,活性炭的用量为湿法磷酸质量的0.25%、活性炭脱色温度为60℃、脱色时间为30 min,湿法稀磷酸从黑色变成无色.     

生物黑炭的施加对连云港滨海盐碱土的改良作用

为了了解生物黑炭的施入对连云港滨海盐碱土的改良效果,采用田间试验研究了生物黑炭施入量对盐碱土土壤性状及小麦温室气体排放量的影响。结果表明,生物黑炭施入对中度盐化滨海盐碱土具有改良作用,土壤pH从8．1降为7．78,同时土壤微生物生物量碳含量最高增加了81．80％。利用静态箱法测定了生物黑炭还田对小麦N2O排放的影响。结果表明,与单施化肥处理相比,添加8和32t·hm-2生物黑炭处理的麦田N2O的排放量分别降低了46．24％和48．39％。综上说明,生物黑炭施入对该研究选择的连云港滨海盐碱土具有改良作用,并且减少了麦田温室气体的排放,具有一定的生态环境效益。     

雪冰中黑碳的研究进展

黑碳气溶胶是大气气溶胶的一种重要成分,沉降在雪冰中可减小雪冰表面的反照率,影响雪冰的融化过程,导致全球和区域气候变化。黑碳气溶胶沉降在雪冰中产生的辐射强迫效应值得关注。中国是黑碳气溶胶排放大国,雪冰黑碳的问题值得关注。现简要介绍雪冰中黑碳研究的意义,着重综述雪冰中黑碳的来源,历史环境记录,现有的计算雪冰中黑碳对反照率影响的方法以及其辐射强迫效应的研究。对未来雪冰中黑碳的研究进行了展望,提出3点今后需加强研究的内容。     

黑米色素稳定性的研究

为研究黑米色素的稳定性,以市售黑米为原料,以蒸馏水为提取溶剂,并以超声波辅助提取黑米色素,考察pH值、自然光、紫外线、温度、以及添加剂等因素对黑米色素稳定性的影响.通过实验可知：在紫外线照射80 min之内对黑米色素稳定性影响不大.在酸性条件下,黑米色素对光照的耐受性较好（在非酸性条件下光照对色素的影响较大）.在20～80℃范围内,温度对黑米色素稳定性影响不明显,当温度超过80℃后对黑米色素稳定性影响较大.黑米色素对食盐、蔗糖的耐受性均较好,可与这些添加剂一起使用.苯甲酸钠、过氧化氢对黑米色素稳定性影响较大.在酸性条件下Vc、柠檬酸对黑米色素稳定性影响较小.黑米色素颜色受酸度影响比较大,在酸性状态下稳定性最好,色泽最佳,适合在酸性食品中使用.该研究为黑米色素的开发利用提供了理论依据.