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The ORB, SIFT, and SURF algorithms are currently common feature matching algorithms. These three algorithms have certain differences in execution speed and matching robustness. In this paper, the data sets provided by Mikolajczyk and Schmid are used to compare the algorithms in terms of execution speed, image transformation robustness, and noise robustness. The conclusion of this paper is that the ORB algorithm is the fastest, the SURF algorithm is the most robust, and the SIFT algorithm has the most feature points.

Modern greenhouse creates suitable crop growth conditions through changing inside temperature, humidity, solar radiation, concentration of carbon dioxide and other environmental factors to raise production and increase economic benefits. The greenhouse microclimate environment model can not only simulate the behavior of a system well but also design the inside controller suitably to be applied to the greenhouse production. The temperature system in a greenhouse microclimate environment can be regarded as a multi-input single-output hybrid system. In this paper, the system was described by Auto Regressive Moving Average model with eXternal inputs (ARMAX). The test data were analyzed for the correlation of input variables and output variable. Then, by means of fading memory recursive least squares, the parameters of the model were identified. Finally, the model was simulated and tested. The actual values were fitted by simulation values and the fitting degree reached 0.91 which showed the model was effective.

This work investigates how climate change may affect streamflow in the water source area of the Middle Route of the South-to-North Water Diversion Project. The IPCC AR4 multi-mode climate models and weather generator were used to generate future possible local meteorological variables, which were downscaled and used in a SWAT model to simulate the future streamflow regime. The results exhibit a significant increase in temperature and a slight increase in precipitation over three benchmark periods. Streamflow decreases in the 2020s and increases after the 2040s. These results raise questions about the future availability of water resources.

Diaryliodonium salts are powerful and widely used arylating agents in organic chemistry. Here we report a scalable, synthesis of densely functionalized diaryliodonium salts from aryl iodides under mild conditions. This two-step, one-pot process has remarkable functional group tolerance, is compatible with commonly employed acid-labile protective group strategies, avoids heavy metal and transition metal reagents, and provides a direct route to stable precursors to PET imaging agents.

Aiming at the hybrid properties of greenhouse temperature-humidity control system, predictive control based on mixed logical dynamical (MLD) model was researched. Firstly, hybrid system model of greenhouse temperature-humidity system was built based on MLD, and two subsystems of greenhouse temperature-humidity system were identified by forgetting factor recursive least squares (FFRLS) under the conditions of open ventilating window and closed ventilating window, respectively. Secondly, predictive control problem was described as mixed integer quadratic problem (MIQP), in which there were measurable but uncontrollable outside disturbance inputs including outside temperature, humidity, solar radiation and wind speed, etc. Time-series models were adopted to predict the disturbance inputs, then by branch&bound algorithm, MIQP was solved to obtain an optimal switching control sequences, based on which finite-time stability of the MLD system was analyzed and simulation control results were compared between the optimal switching signal and two given ones to verify the effectiveness of the methods achieved in this paper.

In this paper, based on mixed logical dynamical (MLD) model, the hybrid formal verification problem of greenhouse temperature-humidity system is investigated. First, the set of desired states is defined as reach set, and the greenhouse temperature-humidity system is modeled in the MLD form. Then the operation safety problems of the greenhouse temperature-humidity system are transformed into hybrid formal verification problems. The reachable sets are computed by multi-parametric toolbox (MPT). At last, the simulation result demonstrates that the greenhouse temperature-humidity system can be driven to desired reach set with proper control actions calculated by hybrid formal verification algorithm. This paper illustrates the effectiveness of the hybrid formal verification method and provides a novel approach to handle the operation safety problems of greenhouse temperature-humidity system.

In this paper, the problem of sliding mode control (SMC) for mixed logical dynamical (MLD) systems is investigated. The sufficient conditions for the finite-time reachability and the asymptotical stability of the designed sliding mode surface are established, and the finite reaching time is given. A sliding mode controller is designed to force the trajectories of the mixed logical dynamical system to be driven onto a prescribed sliding surface and maintained there for all subsequent time. Finally, a numerical example is performed to verify the effectiveness and applicability of the sliding mode control design technique proposed in this paper.

According to the demand of modern greenhouse information management, a greenhouse remote monitoring system was developed based on Android. This system consists of local monitoring module, server and Android client. The local monitoring module accomplishes data acquisition and device control through CAN bus, and interacts with Android client via the MySQL database. Media streaming server is developed using Real Time Streaming Protocol (RTSP) to achieve the greenhouse remote video monitoring. Android client with user-friendly interfaces can realize real-time data display, historical data query, parameter setting, device control, video monitoring etc. Using this system, people can realize real-time and long-distance scientific management of greenhouse. And the labor intensity can be reduced, what is more, the level of greenhouse automation monitoring can be improved.