An analytical tuning approach to multivariable model predictive controllers

Multivariable model predictive control is a widely used advanced process control methodology, where handling delays and constraints are its key features. However, successful implementation of model predictive control requires an appropriate tuning of the controller parameters. This paper proposes an analytical tuning approach to multivariable model predictive controllers. The considered multivariable plants are square and consist of first-order plus dead time transfer functions. Most of the existing model predictive control tuning methods are based on trial and error or numerical approaches. In the case of no active constraints, closed loop transfer function matrices are derived and decoupling conditions are addressed. For control horizon of one, analytical tuning equations and achievable performances are obtained. Finally, simulation results are used to verify the effectiveness of the proposed tuning strategy.     

一种共聚物的合成工艺及阻垢性能研究

以水为溶剂,次亚磷酸钠-过硫酸钠为引发剂,以丙烯酸(AA)和2-丙烯酰氨基．2-甲基丙磺酸(AMPS)为单体合成集膦酸基、羧酸基和磺酸基于一体的共聚物制备工艺和阻垢药效进行了研究。经对反应物浓度、反应条件等各因素进行正交设计和反复实验。结果表明,当摩尔配比为AA∶AMPS∶NaH_2PO_2∶Na_2S_2O_8=80∶10∶3∶1,反应温度为70℃,滴加时间为2h,继续保温反应时间为0．5h时,所制备的共聚物阻垢分散性能显著增加,尤以阻Ca_3(PO_4)_2垢的效果明显提高。     

水乳剂用壬基酚聚氧乙烯配磷酸酯的合成

以壬基酚聚氧乙烯醚(TX-10)、P2O5为原料,合成了水乳剂壬基酚聚氧乙烯醚磷酸酯。通过对还原剂用量等因素的讨论,确定最佳工艺条件为:次亚磷酸钠用量为TX-10的0.4%,n(TX-10)∶n(P2O5)∶n(H2O)=2∶1∶0.8,反应温度60℃,反应时间5h。在此条件下产品的酯化率为96.84%。     

氯中含水测定方法的改进

分析了湿氯气中含水量测定方法存在的问题。经对取样方法和分析方法的改进，建立了快捷，准确的测定方法。     

Pricing strategies with reference effects in competitive industries

This paper examines the effect of reference prices on companies operating within competitive industries. We confirm that even with competition, firms optimally price high in the short term to generate a high reference price and then decrease this price over time. Competitors' prices converge toward each other over time, emphasizing the short‐term nature of reference prices. We then show that pricing optimally to take advantage of reference prices generates a positive externality for other firms in an industry, such that competitors may generate higher profit. The longer the focus of a given firm, the more profit the firm generates, but less relative to its competitors. This arises because the externalities created through pricing high to increase reference prices outweigh the benefits of the higher reference prices themselves. If pricing managers are compensated relative to their competition, this suggests that short‐termism may be implicitly encouraged to the detriment of profit.     

Polynomial time approximation algorithms for proportionate open‐shop scheduling

This paper deals with the presentation of polynomial time (approximation) algorithms for a variant of open‐shop scheduling, where the processing times are only machine‐dependent. This variant of scheduling is called proportionate scheduling and its applications are used in many real‐world environments. This paper develops three polynomial time algorithms for the problem. First, we present a polynomial time algorithm that solves the problem optimally if , where n and m denote the numbers of jobs and machines, respectively. If, on the other hand, , we develop a polynomial time approximation algorithm with a worst‐case performance ratio of that improves the bound existing for general open‐shops. Next, in the case of , we take into account the problem under consideration as a master problem and convert it into a simpler secondary approximation problem. Furthermore, we formulate both the master and secondary problems, and compare their complexity sizes. We finally present another polynomial time algorithm that provides optimal solution for a special case of the problem where .     

油田水处理药剂研究进展

水处理剂是工业用水、生活用水、废水处理过程中所必需使用的化学药剂。介绍了缓蚀剂、阻垢剂、杀菌剂、絮凝剂四种水处理药剂在油田及石化工业中的研究应用现状,并分析提出了其发展趋势。     

50%乙酰甲胺磷WG的配制

以98％乙酰甲胺磷为原药，硅藻土为载体，进行了50％乙酰甲胺磷WG的配方研究。并对样品的分散性、润湿性、崩解性和稳定性进行测定，从中筛选出最佳配方：乙酰甲胺磷50％，十二烷基苯磺酸钠5％，木质素磺酸钠6％，尿素4％，硅藻土补至100％。实验证明：50％乙酰甲胺磷WG配方，其制剂性能优良。     

余度系统中的动态同步和表决控制

在多通道余度系统的研究和应用中,同步问题是整个余度系统正确运行的基本保证。基于多交叉通道模型和同步时间的静态分配策略,提出动态时间容错方法。针对该方法,设计基于时间容错的动态表决控制算法,实现多通道系统中的动态同步。给出动态同步表决控制逻辑,用于控制表决时间并监测表决数据。理论分析和实验结果表明,时间容错的动态表决控制算法扩展了任务处理的时间窗口,与静态同步算法相比,可有效降低通道故障率,提高对瞬时干扰的抵御能力以及余度系统的可靠性。     

基于动态特性的D-LTSV语音端点检测方法

端点检测是语音信号处理的一个关键环节。为提高语音在低性噪比以及非平稳噪声环境下的端点检测性能,在长时信号变化特征(LTSV)的基础上提出一种新的D-LTSV语音端点检测方法。采用Bartlett-Welch方法估计语音谱,分析语音谱在长时域上的熵,利用倒谱的动态特性分析方法提取连续帧熵值的动态变化特征。实验结果表明,D-LTSV综合考虑了语音的非平稳性和帧间非平稳性的动态变化情况,具有比LTSV更好的分辨能力,特别是在低性噪比和非平稳噪声的环境下,D-LTSV的分辨能力提升了50.77%,能够准确地进行端点检测,具有更强的鲁棒性。