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This paper mainly focuses on the optimal output feedback control problem for networked control systems (NCSs) involving multiplicative noises, packet dropouts, input delays and measurement delays. The main contributions of this paper can be concluded as follows. Firstly, different from the previous results, this paper overcomes the barrier of the packet dropouts and measurement delays. Based on the measurement data, the optimal estimator is given. Secondly, by using maximum principle, a sufficient and necessary condition for the optimal control problem is presented. Moreover, the explicit output feedback controller is derived with feedback gain based on the coupled Riccati difference equations. Numerical example is illustrated to show the effectiveness of the proposed algorithm. [ABSTRACT FROM AUTHOR]

In order to further improve the anti-disturbance capability and reduce the conservativeness of unmanned aerial vehicle (UAV) attitude control system, a new enhanced anti-disturbance control law by combining the active disturbance rejection control with disturbance observer-based control is proposed. On the one hand, the disturbances such as external environmental disturbance and complex model nonlinearity are merged into an equivalent disturbance with bounded derivative, which is compensated by the active disturbance rejection control law. On the other hand, the disturbance observer-based control is utilized to estimate the disturbances which have the detailed priori information. The system stability analysis is given by the Lyapunov method. The numerical simulation is carried out to verify the efficiency of the proposed method. [ABSTRACT FROM AUTHOR]

To meet the harsh water plugging conditions for a crack fracture-type rock reservoir of Tahe oilfield in China, which are high temperature, high salinity and above 4000 m underground, a novel delay-expansion water-swelling rubber/OMMT (DWSR) with silty-resistant and lower hydrophilic resin migration behavior was developed. HNBR, semi-HEMA@PU, polyacrylamide (PAM), OMMT and other rubber additives were mechanically blended in an open mill mixer. The semi-HEMA@PU blocked by double bond and isocyanate group was prepared by the reaction of NCO group (50% mole fraction) with hydroxyethyl methacrylate. The semi-HEMA@PU reacted with the amino group from PAM and the unsaturated double bond of HNBR, respectively. A crosslink network constructed among PU, PAM and HNBR matrix made the DWSR/OMMT composite exhibit high salinity resistance and low hydrophilic resin migration features. With an increase of PU content, the crosslinking density of DWSR increases gradually. When the semi-HEMA@PU content was 10 phr, the tensile strength reached a maximum of 13.6 MPa. The influences of OMMT content on swelling behavior were investigated. When the mass content for OMMT was about 1phr, the delayed expansion time was more than 50 h. The presence of OMMT significantly improved the delayed expansion property of DWSR. [ABSTRACT FROM AUTHOR]

In order to efficiently purify and recover the magnetite powder (dense medium) in the process of dry coal preparation of air-dense medium fluidized beds, a new type of fluidized dry magnetic separator was developed in this paper by changing the feeding device and mode, the location and structure of the separating tank, and the particles' movement direction in the separating tank on the basis of the traditional permanent drum dry low-intensity magnetic separator. The magnetic pole arrangement, magnetic field intensity, magnetic field gradient, and action depth of magnetic field of the magnetic system were studied to determine the reasonable parameters of magnetic system for magnetic separation tests. The results of magnetic separation tests for the mixture of magnetite powder and coal powder show that the fluidized dry magnetic separator can improve the grade of magnetite powder as much as possible on the basis of ensuring the recovery of magnetite powder, and obtain the high efficiency purification and recovery of magnetite powder. [ABSTRACT FROM AUTHOR]

This study focused on the occurrence of mercury in coal and the effectiveness of mercury and ash removal by an air dense medium fluidized bed (ADMFB). Results of the study revealed that there was a linear correlation between the mercury content, ash content and density of coal. This was attributed to the fact that mercury mainly exists in high density minerals containing elements with a certain affinity for mercury such as silicon, aluminum, iron, titanium, potassium, sodium, chloride, zinc, and magnesium. There is therefore a good correlation between the separation efficiency of ADMFB and the quality of the clean coal, as well as the overall removal of mercury. By optimizing the operating conditions based on the fitting models, clean coal with a mercury content of 0.0841 ppm and a separation efficiency exceeding 99.8% was obtained. The desirability of the separation effect optimized by fitting models was 0.999. Based on these results, it was concluded that ADMFB is an effective way to remove mercury from coal and reduce its ash content. [ABSTRACT FROM AUTHOR]

To address the increasing health care needs for an ageing population, in this paper, a method of detecting human movements using smartphones is proposed to decrease the risk of accidents in the elderly. The method proposed in this paper uses a mobile phone that has an embedded acceleration sensor to record human motion information that are divided into daily activities (walking, running, going up stairs, going down stairs, and standing still) and falling down. In the process of data acquisition, motion noise contains some interference, and thus the median filter is employed to de-noise and smooth the motion data. Moreover, we extract representative multi-group features and analyse the features by principal component analysis and singular value decomposition to reduce dimensions. Through experimental comparisons with various classifiers, the support vector machine classifier is selected to classify the extracted features. The accuracy of fall detection reached 96.072%, which proved the accuracy of our proposed method. [ABSTRACT FROM AUTHOR]

In this paper, the line of sight (LOS) guidance law is improved to implement tracking toward a moving target. In the presence of sensor noise, an optimal information fusion Kalman filter weighted by scalars is utilized for two-sensor information fusing, improving the trajectory tracking precision. Under the communication delay, n-step ahead Kalman predictor compensates for communication delay and provides LOS guidance law with more accurate target estimates. The results of the simulation demonstrate the feasibility and effectiveness of the proposed control strategy. [ABSTRACT FROM AUTHOR]

Although the need for policy development on arsenic (As) in rice has been recognized and a legally enforceable maximum contaminant level (MCL) for inorganic arsenic (Asi) in rice has been established in China, evidence reported in this article indicates that the risk of exposure to As for the Chinese population through rice is still underestimated. Polished rice from various production regions of China was analyzed for total As and arsenic species using HPLC–ICPMS. Total As concentration ranged 65.3–274.2 ng g−1, with an average value of 114.4 ng g−1. Four arsenic species, including arsenite (As(III)), arsenate (As(V)), dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA), were detected in most rice samples. The Asi (As(III) + As(V)) species was predominant, accounting for approximately 72% of the total As in rice, with a mean concentration of 82.0 ng g−1. In assessing the risk from As in rice, we found that As intake for the Chinese population through rice is higher than from drinking water, with a 37.6% contribution to the maximum tolerable daily intake (MTDI) of As recommended by World Health Organization (WHO), compared with 1.5% from drinking water. Compared to other countries, the risk for the Chinese from exposure to As through rice is more severe due to the large rice consumption in China. Therefore, not only the scientific community but also local authorities should take this risk seriously. Furthermore, more stringent legislation of the MCL for rice should be enacted to protect the Chinese consumer from a high intake of As. [ABSTRACT FROM AUTHOR]