深部纵跨巷道动态分步分段控制及加固技术

针对姚桥矿7253工作面纵跨-650 m轨道大巷地质和生产条件,分析了大巷的变形破坏机制;获得了开切眼前后支承压力分布规律及工作面推进过程中超前支承压力、后方卸压、后期增压的3个变化阶段;提出了动态分步、分段加固原则和加固对策,确定了二次加固的时间,设计了加固支护参数;监测结果表明:新技术对巷道维护效果显著,巷道变形小,围岩整体稳定得到了有效控制。

基于分步动态核主元分析的故障诊断方法

目的研究复杂工业系统动态、非线性特点,提出分步动态核主元分析(Kernel Principal Component Analysis,KPCA)的故障诊断方法.方法该方法首先构造增广矩阵,然后将增广矩阵分成一系列子矩阵,将各子矩阵的构建一个新的数据增广矩阵,并对每个子矩阵使用KPCA提取变量数据的非线性空间相关特征,最后通过监测统计量监测出系统故障,用贡献度的方法识别发生故障变量.结果该方法改进了传统的动态方法,引入分步动态的定义,并且能充分考虑工业过程中的非线性和动态性,更精确的描述工业过程特性,更精确的监测复杂工业系统的故障,并准确的识别出故障变量.结论对热连轧过程中活套故障诊断的仿真结果表明:基于分步动态KPCA的故障诊断方法能准确有效地诊断出故障,并识别出产生故障的原因.

分步动态自回归核主元分析及其在故障诊断中应用

针对滑动窗自适应核主元分析法(KPCA)在处理参数敏感和缓慢劣化问题时存在的"过适应"现象,容易产生漏报的问题,提出了一种分步动态自回归KPCA算法。首先,借鉴动态数据矩阵思想,分步建立初始模型;然后,在滑动窗自适应KPCA的基础上,引入指数加权法则处理实时数据、更新模型;最后,分析算法复杂度,并给出具体实现步骤。利用模拟数据分析分解系数和加权因子对算法的影响,结果表明,与滑动窗自适应KPCA相比,所提方法在参数选择恰当的情况下,模型效率提高了近90%,误报次数几乎降为0,还能通过调整加权因子取值来控制算法的适应能力,以解决多样化的动态问题。将算法应用于压缩机喘振和轴承故障实验数据分析,验证了所提算法处理参数敏感和缓慢劣化问题的能力。

分步自回归核主元分析法及其应用

针对传统核主元分析法诊断动态系统故障可能会出现大量误报、漏报问题,提出一种分步自回归核主元分析法。该方法以分步动态策略为基础建立诊断模型,结合滑动窗口机制和指数加权思想,通过不断加入经加权处理的实时数据更新诊断模型,使用T^2和SPE统计量判断系统是否发生故障。将该方法应用于柴油机气阀机构故障检测,结果表明:该方法既能充分利用原始数据和实时动态信息,自动更新模型,又能减小计算量,更早监测出异常工作状态,提高故障诊断的快速性,还能增大故障敏感度,使诊断结果更加准确可靠。

广义熵权法在大连中期天气预报中的应用

为发挥不同模式数值预报产品的各自优势,提高数值预报产品的综合应用效果,通过引入广义熵权的概念,将数值产品的预报场与分析场或实况资料进行对比分析,进而动态分步跟踪评估不同模式数值预报产品的中期预报效果。利用该方法对大连地区历史天气个例进行中期天气预报模拟试验,并将其用于某次导弹发射任务气象保障。结果表明,该方法能够客观、定量地比较不同模式数值预报产品之间的异同,较好地挖掘各类数值预报产品的阶段性优势以便预报员决策时选用,从而在一定程度上提高中期天气预报的准确率。

DWDM系统四波混频噪声精确评估算法的研究

在考虑到多种影响因素的情况下,得到了FWM(四波混频)噪声标准差的较为精确、高效的评估算法,该算法对优化设计密集波分复用系统具有重要意义。在忽略信道间串扰的基础上,利用动态分步傅里叶算法先行得到单信道内的脉冲传输规律,然后在此基础上精确求解决定FWM效率大小的重叠函数。实例计算结果表明:FWM效率大小与脉冲在传输过程中的变化有关,在群速度色散系数绝对值相对较小、归一化的特征宽度相对较大、入射脉冲峰值功率相对较大时,这种关联度比较大。啁啾系数为正,取值较大,且传输速率相对较高时,不能忽略脉冲随传输距离的变化对FWM效率的影响。

Synchronization and Bifurcation of General Complex Dynamical Networks

In the present paper, synchronization and bifurcation of general complex dynamical networks are investigated. We mainly focus on networks with a somewhat general coupling matrix, i.e., the sum of each row equals a nonzero constant u. We derive a result that the networks can reach a new synchronous state, which is not the asymptotic limit set determined by the node equation. At the synchronous state, the networks appear bifurcation if we regard the constant u as a bifurcation parameter. Numerical examples are given to illustrate our derived conclusions.

Validation of a Marker Model for Gait Analysis with Wearable Exoskeletons

The aim of the present study was to develop and validate a new marker model for optoelectronic systems adapted to wearable devices, in order to have an analysis tool for kinematic gait evaluation of reproduced patterns by exoskeletons. The marker model has a total of 36 retro-reflective markers attached bilaterally to anatomical landmarks during the static measures （without exoskeleton） and 28 markers at the dynamics measures （with exoskeleton）. The main difference between others kinematic models and the described adapted model was the placement of the three markers in the back thigh and the other three in the back calf, what allowed removing the hip, thigh, knee, tibia and ankle markers. The proposed adapted marker model could be an effective tool to validate the joint movement and velocities of those wearable exoskeletons that at present have been developing.

Sensitivity of Precipitation in Aqua-Planet Experiments with an AGCM

The sensitivity of precipitation was studied by conducting control aqua-planet experiments(APEs) with a model to determine atmospheric general circulation.The model includes two versions: that with a spectral dynamical core(SAMIL) and that with a finite-volume dynamical core(FAMIL).Three factors were investigated including dynamical core,time-step length,and horizontal resolution.Numerical results show that the dynamical core significantly affects the structure of zonal averaged precipitation.FAMIL exhibited an equatorial precipitation belt with a single narrow peak,and SAMIL showed a broader belt with double peaks.Moreover,the time step of the model physics is shown to affect the zonal-averaged tropical convective precipitation ratio such that a longer time step leads to more production and consumption of convective available potential energy and convection initiated away from the equator,which corresponds to equatorial double peaks of precipitation.Further,precipitation is determined to be sensitive to horizontal resolution such that higher horizontal resolution allows for more small-scale kinetic energy to be resolved and leads to a broader probability distribution of low-level vertical velocity.This process results in heavier rainfall and convective precipitation extremes in the tropics.Abstract The sensitivity of precipitation was studied by conducting control aqua-planet experiments(APEs)with a model to determine atmospheric general circulation.The model includes two versions:that with a spectral dynamical core(SAMIL)and that with a finite-volume dynamical core(FAMIL).Three factors were investigated including dynamical core,time-step length,and horizontal resolution.Numerical results show that the dynamical core significantly affects the structure of zonal averaged precipitation.FAMIL exhibited an equatorial precipitation belt with a single narrow peak,and SAMIL showed a broader belt with double peaks.Moreover,the time step of the model physics is shown to affect the zonal-averaged tropical convective precipitation ratio such that a longer time step leads to more production and consumption of convective available potential energy and convection initiated away from the equator,which corresponds to equatorial double peaks of precipitation.Further,precipitation is determined to be sensitive to horizontal resolution such that higher horizontal resolution allows for more small-scale kinetic energy to be resolved and leads to a broader probability distribution of low-level vertical velocity.This process results in heavier rainfall and convective precipitation extremes in the tropics.

Error code analysis and selection principle of M-ary modulation in network-based control systems

Error codes induced by M-ary modulation and modulation selection in network-based control systems are studied.It is the first time the issue of error codes induced by M-ary modulation is addressed in control field.In network-based control systems,error codes induced by noisy channel can significantly decrease the quality of control.To solve this problem,the network-based control system with delay and noisy channel is firstly modeled as an asynchronous dynamic system(ADS).Secondly,conditions of packet with error codes(PEC)loss rate by using M-ary modulation are obtained based on dynamic output feedback scheme.Thirdly,more importantly,the selection principle of M-ary modulation is proposed according to the measured signal-to-noise ratio(SNR)and conditions of PEC loss rate.Finally,system stability is analyzed and controller is designed through Lyapunov function and linear matrix inequality(LMI)scheme,and numerical simulations are made to demonstrate the effectiveness of the proposed scheme.

Function Projective Synchronization of Fractional-Order Hyperchaotic System Based on Open-Plus-Closed-Looping

The purpose of this paper is to analyze the dynamic behavior of fractional-order four-order hyperchaotic Lii system, and use the Open-Plus-Closed-Looping （OPCL） coupling method to construct the system＇s corresponding response system, and then implement function projective synchronization （FPS） of fractional-order drive-response system with system parameters perturbation or not. Finally, the numerical simulations verify the effectiveness and robustness of this scheme.

An improvement to the reciprocating gait orthosis for aiding paraplegic patients in walking

As the conventional reciprocating gait orthosis(RGO)has been deemed incapable of facilitating the patients’passive movement with significant gait discrepancies and distortion,in addition to characteristics such as poor stability,and negligible knee joint rehabilitation,a power assisted reciprocating gait orthosis(PARGO)was designed.Drive devices were added to the hip and knee joints of the RGO.Through efficient implementation of structural components,the number of the required motors was reduced,therefore decreasing the weight of the orthosis.The PARGO knee joint’s structural principle was analyzed to characterize the effect of the PARGO’s single-axis knee joint design on wear comfort,thereby providing a basis for the wear of the PARGO.By analyzing the sagittal movement patterns of the hip and knee joints during normal human gait,kinematic analysis was carried out to obtain the input patterns of the PARGO hip and knee joint drive motors,enabling the patients to more accurately reproduce the normal gaits of hip and knee joints during the rehabilitation training with the aid of the PARGO,and the control process of the PARGO was studied.Finally,a prototype of the PARGO was developed,and experimentation was carried out to demonstrate the feasibility of the improved orthosis.

Effects of electroacupuncture pretreatment on motor function and cerebral blood flow in MCAO model rats

Objective:To observe the effects of electroacupuncture(EA)pretreatment on motor function,cerebral blood flow,cerebral infarction volume,and vascular endothelial growth factor(VEGF)level in middle cerebral artery occlusion(MCAO)model rats.Methods:Twenty-four male Sprague-Dawley rats were randomly divided into a normal group,a model group,and an EA group,with eight rats in each group.The middle cerebral artery ischemia-reperfusion model was established by the suture-occluded method in the model group and the EA group,while not in the normal group.The EA group was pretreated with EA at bilateral Fengchi(GB20)before model preparation,once a day for 30 min each time for a total of 7 d.The changes in the CatWalk gait parameters,modified Bederson neurological deficit score,cerebral blood flow,cerebral infarction volume after ischemia,and VEGF level in the brain tissue of rats in each group were observed.Results:Compared with the normal group,the modified Bederson neurological deficit score in the model group and the EA group increased after modeling(P<0.05),and the CatWalk gait parameters(one-leg stance duration,gait cadence,and gait cycle)were all changed(P<0.05).Compared with the model group,the modified Bederson neurological deficit score in the EA group decreased(P<0.05),and the CatWalk gait parameters improved(P<0.05).Immediately after ischemia,the cerebral blood flow in the normal group was greater than that in the model group and the EA group(P<0.05);after reperfusion,the cerebral blood flow in the EA group was greater than that in the model group(P<0.05).Compared with the normal group,the cerebral infarction volume in the model group and the EA group increased(P<0.05).Compared with the model group,the cerebral infarction volume in the EA group decreased(P<0.05).The expression level of VEGF-positive cells in the rat brain tissue in the model group was higher than that in the normal group(P<0.05),and was higher in the EA group than in the model group(P<0.05).Conclusion:EA pretreatment improves the limb motor function in MCAO model rats,alleviates the symptoms of neurological deficits,promotes the recovery of cerebral blood flow,reduces the cerebral infarction area after MCAO modeling,and increases the VEGF expression in the brain tissue.