超声波/零价铁协同降解氯代芳香化合物定量结构与性质关系的研究

在相同条件下,测得超声波/零价铁(US/Fe~0)协同降解18种氯代芳香化合物的准一级速率动力学常数(logk)。以SIM- CA-P软件的PLS回归分析法,研究反应降解速率常数与物质定量结构的关系(QSPR),得到最佳QSPR模型,并经验证。模型的分析结果表明:在US/Fe~0体系中,物质的亨利常数H、最终生成热HOF、最高占据轨道能E_(homo)和疏水性常数logK_(ow),是影响氯代芳香有机物降解的主要因素。但E_(lumo)-E_(homo),极化率α,总电子能量TE和分子的双中心电子推斥能EE_2的影响也不可忽视。     

量子化学方法预测多氯联苯(PCBs)的色谱保留值及理化性质

采用AM1半经验算法，计算了多氯联苯（PCBs)所有209种可能分子结构的6种量子化学参数－分子平均极化率（α），偶极距（μ），分子最高占据轨道能（Ehomo)，分子最低未占据轨道能（Elumo),分子中氢原子的量正形式电荷（qH^ )和分子中原子的最负形式电荷（q^-)，在此基础上依据理论线性溶解能相关模型（TLSER），通过正向逐步多元线性回归方法建立了PCBs气相色谱保留值参数（RRT）和两种理化性质－水溶解度（－logSw),正辛醇／水分配系数（logKow)的定量预测方程。检验结果表明：方程相关性显著，精度较高，物理意义明确。     

多氯联苯分子空间坐标与气相色谱相对保留时间的QSPR研究

应用ChemWindow和ChembioOffice绘图软件对209种多氯联苯化合物(PCBs)作图,通过分子最低能量模块计算得到其空间稳定构型,空间构型对应着分子空间坐标,固定坐标原点,得到同一坐标系的分子空间坐标。对PCBs分子空间坐标研究,定义了2个描述符,原子距离指数(Y_S)和分子空间特征指数(Y_F)。用多元线性回归方法获得了多氯联苯化合物的气相色谱相对保留时间(GCRRT)与该空间距离指数之间良好的定量结构一性质相关(QSPR)模型,定义的指数易于计算和运用。模型相关性良好(R=0.990),具有较高的预测能力和可靠性,从另一角度为QSPR研究提供一个新的思路。     

量化参数对脂肪醇的-lgSw、lgKow的QSPR研究

基于多元线性回归技术发展了对脂肪醇在298K下的水溶性作出精确估计的定量结构-性质关系。通过从头算分子轨道理论得到描述脂肪醇分子的结构描述符，如Ehomo,Elumot C-O键上碳原子电荷Qc。在HF／6-31g(d)水平下对脂肪醇分子进行全几何参数优化从头算。Qc容易获取，表征了醇分子同分异构体之间的结构差异。多元回归分析结果表明醇分子的-lgSw、lgKow都随分子所含碳原子数N的增加而增加，随着C-O键上碳原子电荷Qc的增大而减小，复相关系数均在0．99以上。从头算所得的量化参数Qc用于与脂肪醇的水溶解性关联优于分子连接性指数。     

Quantitative analysis and synthesis for networked control systems with non‐uniformly distributed packet dropouts and interval time‐varying sampling periods

This paper is concerned with quantitative analysis and synthesis for a networked control system under simultaneous consideration of non‐uniformly distributed packet dropouts, interval time‐varying sampling periods and network‐induced delays. A new packet dropout separation method is proposed to separate packet dropouts from the lump sum of network‐induced delays and packet dropouts. An interval time‐varying sampling period approach, which is more general than a switched sampling period approach, is presented to model the variation of the sampling period. Then a packet dropout decomposition‐based Lyapunov functional is constructed to drive some stability criteria. Based on these stability criteria, a state feedback controller is designed to asymptotically stabilize the networked system in the sense of mean‐square. Numerical examples are given to illustrate the effectiveness of the obtained results. Copyright © 2013 John Wiley & Sons, Ltd.     

利用条件概率和Gibbs抽样技术为分布估计算法构造通用概率模型

本文针对传统分布估计算法在建立概率模型时面临的各种困难,提出一种基于条件概率和Gibbs抽样的概率模型,能有效改进分布估计算法的通用性.使用该模型的分布估计算法利用进化过程中有前途的优秀个体构造出多个监督学习样本集,并对每个样本集估计出对应分量的条件概率,再使用这一组条件概率进行Gibbs抽样产生新的个体替代种群中的劣等个体.通过仿真实验表明,改进后的算法能够求解出可加性降解函数的全局最优解,表现出较强的全局优化能力.     

Remote robotic underwater grinding system and modeling for rectification of hydroelectric structures

A submersible grinding robot has been designed to automate the dam gate metallic structure repair process. In order to measure and control the amount of material removed during the process, an empirical approach for modeling the material removal rate (MRR) of the underwater grinding application is proposed and presented in this paper. The objective is to determine the MRR in terms of the process parameters such as cutting speed and grinding power over a range of variable wheel diameters. Experiments show that water causes drag and a significant loss of power occurs during grinding. An air injector encasing the grinding wheel has been prototyped, and it is shown that power loss can be reduced by up to 80%. A model, based on motor characterization and empirical relations among system and process parameters, is developed for predicting MRR which will be used for the robotic grinding control system. A validation is carried out through experiments, and confirms the good accuracy of the model for predicting the depth of cut for underwater grinding. A comparative study for dry and underwater grinding is also conducted through experiments and shows that the MRR is higher for underwater grinding than in dry conditions at low cutting speeds.     

A motion control framework for autonomous water sampling and swing-free transportation of a multirotor UAV with a cable-suspended mechanism

In this work, we present an end-to-end solution for autonomous water sampling by utilizing an unmanned aerial vehicle (UAV) with a cable-suspended mechanism. Towards this direction, a sampling mechanism is initially designed in such a manner that the water sampling success ratio is maximized. However, the disturbances, acting on the submerged mechanism due to the water flow during the sampling procedure, impede the stabilization of the vehicle above the desired sampling position. Consequently, to achieve the precise hovering of the UAV, the vehicle's sensor suite is further augmented with a load cell, a depth sensor, an ultrasonic sensor, and a camera. The respective measurements are appropriately fused by employing an extended Kalman filter (EKF). Hence, an estimate of the disturbances is available in real-time and is incorporated into a Model Predictive Control scheme which compensates for the aforementioned disturbances and stabilizes the vehicle above the sampling location. Finally, a complete water sampling mission entails the safe and swing-free transportation of the mechanism towards the sampling location and, then, to a position where the collected samples are postprocessed by human operators. Consequently, a model predictive controller is employed which ensures the navigation of the vehicle to the desired waypoints while minimizing the swinging motion of the mechanism. The state of the mechanism is obtained by fusing measurements provided by the load cell and the camera with an EKF. The performance of the proposed framework, which aims to address all the aspects of a water sampling mission, is demonstrated through real experiments with an octorotor.     

An EOQ model for deteriorating items with price- and stock-dependent selling rates under inflation and time value of money

This study applies the discounted cash flow (DCF) approach for the analysis of a replenishment problem over a finite planning horizon. Thus, a deterministic economic order quantity (EOQ) inventory model taking into account inflation and time value of money is developed for deteriorating items with price- and stock-dependent selling rates. An efficient solution procedure is presented to determine the optimal number of replenishment, the cycle time and selling price. Then the optimal order quantity and the total present value of profits are obtained. Numerical examples are presented to illustrate the proposed model and particular cases of the model are also discussed.     

Comparisons of air traffic control implementations on an associative processor with a MIMD and consequences for parallel computing

This paper has two complementary focuses. The first is the system design and algorithmic development for air traffic control (ATC) using an associative SIMD processor (AP). The second is the comparison of this implementation with a multiprocessor implementation and the implications of these comparisons. This paper demonstrates how one application, ATC, can more easily, more simply, and more efficiently be implemented on an AP than is generally possible on other types of traditional hardware. The AP implementation of ATC will take advantage of its deterministic hardware to use static scheduling. The software will be dramatically smaller and cheaper to create and maintain. Likewise, a large AP system will be considerably simpler and cheaper than the MIMD hardware currently used. While APs were used for ATC-type applications earlier, these are no longer available. We use a ClearSpeed CSX600 accelerator to emulate the AP solutions of ATC on an ATC prototype consisting of eight data-intensive ATC real-time tasks. Its performance is compared with an 8-core multiprocessor (MP) using OpenMP. Our extensive experiments show that the AP implementation meets all deadlines while the MP will regularly miss a large number of deadlines. The AP code will be similar in size to sequential code for the same tasks and will avoid all of the additional support software needed with an MP to handle dynamic scheduling, load balancing, shared resource management, race conditions, false sharing, etc. At this point, essentially only MIMD systems are built. Many of the advantages of using an AP to solve an ATC problem would carry over to other applications. AP solutions for a wide variety of applications will be cited in this paper. Applications that involve a high degree of data parallelism such as database management, text processing, image processing, graph processing, bioinformatics, weather modeling, managing UAS (Unmanned Aircraft Systems or drones) etc., are good candidates for AP solutions. This raises the issue of whether we should routinely consider using non-multiprocessor hardware like the AP for applications where substantially simpler software solutions will normally exist. It also raises the question of whether the use of both AP and MIMD hardware in a single hetergeneous system could provide more versatility and efficiency. Either the AP or MIMD could serve as the primary system, but could hand off jobs it could not handle efficiently to the other system.