Automatic fire detection, which can detect and raise the alarm for fire early, is expected to help reduce the loss of life and property as much as possible. Due to its advantages over traditional methods, image processing technology has been applied gradually in fire detection. In this paper, a novel algorithm is proposed to achieve fire image detection, combined with Tchebichef (sometimes referred to as Chebyshev) moment invariants (TMIs) and particle swarm optimization-support vector machine (PSO-SVM). According to the correlation between geometric moments and Tchebichef moments, the translation, rotation, and scaling (TRS) invariants of Tchebichef moments are obtained first. Then, the TMIs of candidate images are calculated to construct feature vectors. To gain the best detection performance, a PSO-SVM model is proposed, where the kernel parameter and penalty factor of support vector machine (SVM) are optimized by particle swarm optimization (PSO). Then, the PSO-SVM model is utilized to identify the fire images. Compared with algorithms based on Hu moment invariants (HMIs) and Zernike moment invariants (ZMIs), the experimental results show that the proposed algorithm can improve the detection accuracy, achieving the highest detection rate of 98.18%. Moreover, it still exhibits the best performance even if the size of the training sample set is small and the images are transformed by TRS.

To achieve automatic rolling of an unmanned vibratory roller, the path following control model of the vibratory roller was built and the influence of drum vibration is considered since the roller always works in the vibration condition. The vibration dynamic model was first established. The dynamic model of the vibratory roller under the influence of exciting force was then developed. The heading following control algorithm based on preview strategy was designed to control the path following errors in unmanned automatic rolling. The control performance of the algorithm was analyzed by simulation based on the vibration dynamic model and the dynamic and kinematic models of the vibratory roller. The control performance was also verified by the field automatic rolling experiments. Experimental results show that the maximum absolute lateral error of line path following is 24.5 cm in vibration rolling and 19.5 cm in non-vibration rolling at the traveling speed of 0.83 m/s. The average absolute lateral errors in vibration and non-vibration rolling are both less than 10 cm. The experimental results verify the effectiveness and achievability of the control algorithm for unmanned vibration rolling. Besides, the ratio of completely compacted area to the whole set area is 97.28% in the field automatic rolling experiment, which meets the requirements for practical use.

Electromagnetic forming (EMF) is a kind of high-energy-rate forming technology which uses pulsed electromagnetic forces to achieve rapid plastic deformation of workpieces. It can significantly improve the forming limit and formability of lightweight alloys and has been widely used in the field of tube forming. However, in the existing tube forming systems, the electromagnetic force between the tube and the coil is mainly dominated by a repulsive force. When flaring the tube, the coil must be placed inside the tube, which is not suitable for the forming of small tubes. In order to solve this problem, a method of flaring small tube with an outer coil is developed, where the coil current is generated by a dual-power supply system and a significant attractive electromagnetic force between the coil and the tube is produced for flaring forming. The feasibility of the method has been demonstrated by both numerical simulations and experiments. It has been shown that the flaring of an A1060-O aluminum alloy tube with diameter of 20 mm can be successfully realized, and the maximum radial deformation is about 4.88 mm. Meanwhile, it has been pointed out that the performance of tube flaring can be further improved by changing the relative position of tube and coil and the discharge voltage value of the dual-power supply system. The obtained results provide a new flaring tool for small tubes and expand the application of electromagnetic forming technology in tube processing. INDEX TERMS Electromagnetic forming, electromagnetic attractive force, numerical simulation, metal tube, flaring.

Objective. The purpose of this study is to explore the effectiveness and safety of Montgomery T-tube placement in treating Cotton-Myer IV subglottic airway atresia after bi-level airway recanalization. Methods. This study is a retrospective study. 11 patients who were treated for IV subglottic airway atresia between January 2017 and January 2019 in the Second Affiliated Hospital of Jiaxing University were involved in this study. The 11 patients all had undergone tracheotomies at our hospital, and they were transferred to the Department of Pulmonary and Critical Care Medicine for Montgomery T-tube placement after bi-level airway recanalization when their subglottic airway was atretic. Patients were observed for their clinical manifestations after placement. The effectiveness of T-tube placement after bi-level airway recanalization was assessed. The incidence of short-term and long-term complications after surgery was assessed. Patients were followed up for 3 to 24 months for evaluating their airway recovery. Results. T-tubes were successfully placed in 11 patients. The atretic airways of all patients were recanalized after treatment. Eight patients got restoration of vocal ability, and 3 patients could only say simple words. None of the patients needed assisted oxygen inhalation. The SpO2 average level was increased from 95 ± 2 % before treatment to 97 ± 3 % after treatment. Patients had significant relief of cough or sputum, and they had less difficulty in dyspnea. All short- or long-term complications were self-relieved or controlled without further malignant progression after treatment by doctors. The average postoperative extubating time was ( 14.86 ± 3.62 ) months. Conclusion. The application of Montgomery T-tube placement in treating Cotton-Myer IV subglottic airway atresia after bi-level airway recanalization is well effective and safe for patients, and it can be promoted in clinical treatment.

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