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The increasing demand for forestry resources is driving the need for smarter systems capable of saving and protecting forests that can optimize agile forestry production. This study uses the continuous hot-pressing process of wooden medium-density fiberboard (MDF) to investigate the possibility of automatic quality control of the continuous flat pressing process. For this purpose, conceptual digital twin modeling for mechanism and sequence parameter control was conducted based on the cellular automata (CA) theory. A distributed coordination mode framework was constructed, and a craft control programming method was proposed for the quality control of MDF continuous flat pressing. Based on the MDF continuous flat press craft mechanism and control standards, a framework of five distributed flat press cooperative control mode elements for the cylinder array of the continuous panel system (CPS) was defined. To satisfy the distributed distance servo and pressure servo demands of the multi-stage hot pressing craft design, five kinds of synergy collaborative control modes of multiple rack groups were constructed using mode elements: For the four types of typical deviations in slab production, i.e., thickness, slope, depression, and bulge, a multi-zone mutual cooperative mode craft control sequence was programmed. According to the type and intensity of real-time deviation, the corresponding regulation sequence was applied. This effectively counteracts the deviation caused by the uncertainty interference due to the multi-field coupling effect in actual production. The application tests demonstrate that the adjustment and response time of the continuous flat press were greatly improved, and the quality superiority rate is controlled above 95%, thereby confirming the effectiveness of the control strategy.

Contourlet transformation has good characteristic in dealing with details in high frequency of the image information, and better directionality and sparsity. An improved algorithm using Str...

Considering the linear motion of particleboards in the production line, the detection of surface defects in particleboards is a major challenge. In this paper, a method based on moving target tracking is proposed for the detection of surface defects in particleboards. To achieve this, the kernel correlation filter (KCF) target tracking algorithm was modified with the median flow algorithm and used to capture the moving targets of surface defects. The defect images were extracted by a Sobel operator, and the defect number, the defect area, and the degree of damage were calculated. The level of surface defect in particleboards was evaluated by fuzzy pattern recognition. Experiments were then carried out to prove the effectiveness and accuracy of the proposed method.

Fault-tolerance is one of important issues in wireless sensor network (WSN) since it is critical in real deployed environments to realize network stability and reduce demand times. In this paper, we propose primary-backup technique by creating a backup path for every sensor on a primary path of data transmission. Especially, we take high reliability path as selected primary or backup path method. The experimental results show that the algorithm not only has the low packet delivery ratio characters, but also ensures the reliability of topology paths and extends the network life-cycle efficiently.

In view of the problem that existing Media Access Control (MAC) protocols can not provide real-time monitor on network conditions, this paper puts forward a new MAC protocol—Predict and Feedback MAC (PFMAC) which can predict the channel’s congestion level reasonably. The dominant idea of the new scheme is to record the channel’s busy or idle situation in the backoff stage by sending Sensor Nodes (SNs), and according to the congestion level every SN can change the contention window adaptively when send packets successfully to minimize collisions, saving energy and channel resources. The result of simulation shows that compared with other MAC protocols, the PFMAC protocol can improve network throughput and reduce energy consumption in high speed network environment.

In order to realize high-precision position tracking control for (Medium Density Fiberboard, MDF) continuous hot press hydraulic position servo system in the presence of interior parameter perturbations and external load disturbance, an adaptive backstepping sliding mode control strategy with fuzzy disturbance observer (FDO) is presented. Firstly, a modified FDO is designed to estimate and compensate the interior parameter perturbations and external load disturbance of the system. Secondly, the backstepping sliding mode controller is designed and adaptive algorithm is used to online estimate the uncertainty of the system. Thirdly, the convergence of tracking error and the asymptotic stability of system are strictly proved according to Lyapunov stability theory. The results of simulation experiments indicate that the controller has strong robustness against the interior parameter perturbations and external load disturbance. Moreover, the controller has good performance including fast response, high tracking accuracy and small steady-state error.

With multiprocessor systems, redundant scheduling is a technique that trades processing power for increased reliability through redundancy. One novel approach, called primary-backup task scheduling, is a large number of used in hard real-time multiprocessor systems to guarantee the deadlines of tasks faults. In this paper, we analysis and compare the scheduling algorithm based on primary-backup replication in current distributed system. Finally, the important features that fault-tolerant Task Scheduling in Multiprocessor Systems based on primary-backup are summarized, and the future research strategies and tends are given.

In WSNs, energy conservation is the primary goal, while throughput and fault tolerance are other important factor. According to wireless sensor network nodes energy consumption, hardware failure and communication factors, in this paper, an evolving network method based on complex network theory of small-world Kleinberg model is proposed, which uses long links and short links in partial view information to build inter-cluster topology. Theoretical analysis and simulations show that the network lifetime is longer 27% than DECDC in the WSN topology which uses this method when the node failure probability is 0.2. And it has a good balance of energy consumption and lower cost. Thus the topology which uses the method to build has good fault-tolerant and robustness.