Stationary policies for lower bounds on the minimum average cost of discrete‐time nonlinear control systems

The paper deals with the control problem of discrete‐time nonlinear systems. The main contribution of this note is to present conditions that assure the existence of stationary policies that generate lower bounds for the minimal long‐run average cost. These lower bounds coincide with the optimal solution when a mild convergence assumption holds. To illustrate the results, the paper presents an application for the simultaneous state‐feedback control problem, and the derived strategy is used to design a real‐time simultaneous control for two direct current motor devices. The dynamics of these two devices are written in terms of a nonlinear algebraic matrix recurrence, which in turn represents a particular case for our general nonlinear approach. The optimal gain for the corresponding simultaneous state‐feedback problem is obtained, and such a gain was implemented in a laboratory testbed to control simultaneously the two direct current motors. Copyright © 2013 John Wiley & Sons, Ltd.     

浅议我国成品油销售企业竞争力的提升

为了应对加入WTO后我国成品油销售面临的竞争，提出以低成本战略、企业再造战略、品牌营销战略、服务营销战略作为提升成品油销售企业竞争力的重要策略。     

浅谈信息管理技术在建筑施工企业项目管理中的应用简

信息技术与先进的管理思想相结合,创造性地利用信息技术,可以高效提升企业管理创新能力。本文从施工管理的视角,阐述了在石油化工行业大型炼化工程项目管理中,如何利用信息管理技术,构架起综合项目管理平台,采用工程验收平台和POWER ON项目管理软件来进行二次开发,结合具体工程实践,实现网上机械车辆结算。     

Incubating superphosphate in ‘dry’soil can reduce its effectiveness

Single superphosphate was incubated for six months at 25°C in soil which had been subject to one of three moisture treatments. These were: dried in a glasshouse, dried at a constant temperature of 25°C, or moist soil. Phosphorus (P) effectiveness was then compared with effectiveness of P from freshly-applied superphosphate using yields of wheat (Triticum aestivum) and triticale (×Triticosecale) tops in pot experiments.Incubation in soil which had been dried at 25°C did not decrease the effectiveness of the P. Incubation in moist soil decreased it to about 20% of the effectiveness of freshly-applied P in one case and to about 50% in the other case. Incubation in soil which had been dried in a glasshouse also decreased its effectiveness. The decrease varied with conditions, but in two cases the P was 70% as effective as freshly-applied P, and in one case only 45% as effective. Presumably sufficient moisture was present in the soil dried in the glasshouse to enable water-soluble P present in the fertilizer to react with the soil.     

多孔催化剂效率因子的多组分扩散模型(Ⅴ) 表面中毒并伴有平衡死区圆柱状催化剂效率因子的有限元求解

针对表面中毒并伴有平衡死区二维圆柱状催化剂的反应-扩散偏微分方程组的特殊性,引入有限元方法求解该类问题,建立了求解步骤。实际计算所得效率因子与实验值对照表明,本法结果准确,过程简单,容易推广应用于各种相类似的体系。     

新企业会计准则对装备价格管理的影响及启示

与原会计准则相比,新会计准则在会计基本原则和会计要素的计量方面发生了较大的变化,新准则在内容上充实成本要素,在可操作性上更加强调规范会计信息的质量。通过对新会计准则的变化内容、特点及作用方面分析,研究其实施对装备价格管理工作的影响,探讨新会计准则环境下如何提高装备价格管理水平等问题。     

基于分组管理的无线mesh网多信道分配算法*

为了合理利用多信道来提高无线网络吞吐量,针对基于802.11标准无线mesh网的业务特点,提出了基于分组管理的分布式多信道分配算法。该算法将节点接口分为回程接口与转发接口,并使回程接口分配到在干扰区域内干扰值尽可能小的信道。仿真实验结果表明,该算法可以减少区域干扰,并可充分利用信道的多样性和得到较高的网络吞吐量。     

网格环境下基于传输代价的副本优化策略*

在深入分析影响副本策略性能的各种因素的基础上,将多种因素和传输代价联系起来进行建模,提出一种副本优化策略。优化策略基于传输代价,综合考虑文件访问次数、大小、存在时间等多种因素,并充分利用文件访问次数的集合特征,提供了一个动态、全局的副本管理方法。在网格仿真器OptorSim中对基于传输代价的优化策略进行了实现和评估分析。实验分析证明,优化后的副本策略较现有策略有明显优势。     

银行监管有效性体系的建构

为提升我国银行监管的有效性,在借鉴国际社会银行监管经验的基础上,采用比较分析的方法,构建适合我国国情的银行监管有效性指标体系．利用该指标体系对我国银行监管现状进行分析,结果表明,我国银行监管收益指标中的稳定性指标比较理想,但存款人保护等指标仍有较大提升空间．银行监管成本高,即银行监管应在提高各项收益指标的前提下,尽可能削减监管成本．     

Delay-dependent guaranteed cost control for uncertain discrete-time Markovian jump linear systems with mode-dependent time-delays

In this paper,the problem of guaranteed cost control for a class of uncertain discrete-time Markovian jump linear systems with mode-dependent time-delays and a given quadratic cost function are investigated. Attention is focused on designing a memoryless state feedback control law such that the closed-loop system is robust stochastically stable and the closed-loop cost function value is not more than a specified upper bound,for all admissible uncertainties. The key features of the approach include the introduction of a new type of suitable stochastic Lyapunov functional and free weighting matrices techniques. Sufficient conditions for the existence of such controller are obtained in terms of a set of linear matrix inequalities. A numerical example is given to illustrate the less conservatism of the proposed techniques.