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In view of LoRa low bit rate spread spectrum communication, this paper first analyzes the spatial transmission of wireless communication, and analyzes the relevant factors of transmission distance in the transmission process. Firstly, the influencing factors of distance of receiving and transmitting antennas are analyzed, including the transmitting power of the transmitter, the sensitivity of the receiver, the gain of the transmitting antenna, the gain of the receiving antenna, the carrier frequency, the insertion loss of the base station’s transmitting antenna’s feeders and the air transmission loss caused by the environment in the ideal environment. Thus, a theoretical analyzation about influencing factors of the transmission distance is acquired. The basic principle of LoRa spread spectrum communication is analyzed and compared with FSK modulation. Finally, through a large number of tests, transmission distance, packet loss rate, signal quality, signal-to-noise ratio index are analyzed, and the comparison results between the actual measurement and the theory are obtained.

The article analyses petroleum pipe's features and presents a method of recognizing petroleum pipe welding seam which is based on V structure produced at petroleum pipe surface by laser light. It firstly does Image binarization to the welding seam picture, and then uses Image Enhancement technology, filter technology and corrosion algorithm of morphologic to recognize the welding seam center. By applying to practical project, it is verified that the method has good application of oil pipeline welds.

The article presents a new arithmetic which uses chain code to recognize fire flame’s apex angles in fire detection processing. It applies a concept of custom slip window and defines flame’s apex angle acutance index to estimate apex angle’s type which could be I type or II type. This method also presents mathematics model and theory deduction and defines relative height parameter as the criterion of apex angles. The recognition method based on chain code is good at inflexion location with a higher speed and better anti-yawp capability rather than traditional method.

A new intelligent Mechanical Ventilation Bed is introduced for the first time. The method of change posture synchronized with respiratory and change pressure to hanging abdomen on prostrate position obliquely is used cleverly. Through the role of gravity and inertia force, the breathing potential of diaphragm is mobilized and plays its role fully, so that the lung tidal volume multiplied. The innovative design of mechanical bed reflects the principles of humanization of medical equipment fully. On intelligent control algorithms, the fake-period algorithm is used innovatively, not only the assistant ventilation synchronized with breath ventilation is realized, but also the synchronization control, security and stability of the system is improved.

Against the inaccuracy and poor real-time of traditional image-identifying arithmetic of steel pipe welding seam, this paper offer a new method of disperse convolution. Firstly, a self-adaptive grey transferring method is put forward according to the disadvantage of traditional grey transformation method of fixed threshold, before filter function is established by the statistical characteristics of welding seam images and elements, and image-identifying arithmetic of disperse convolution is adopted to identify the welding seam center. Finally, the method, which has been widely used in industrial production, is validated to be of high anti-interference capability, high calculating speed, accurate allocation and easy implementation.

Currently in fire alarm system, detector bring on high failing alarm rate and high mistaking alarm rate within nearby territory value because of some kinds of reason. In this article, a solution is proposed that the detector characteristic values taken a kind of pattern to carry on the decision-making classification. The Bayes decision-making method is used in the classified process. Pattern classification of alarm is simplified to two values classification in continual condition. Single vector decision-making function based on multidimensional normal distribution is proposed according to the feature of the fire detector data. At the same time the classification differentiation function is produced based on the principle that the classification average risk is the smallest. Finally the classification distinguish function is simplified in different condition. The experiment indicates that new solution is found in this article that it can effectually reduce failing alarm rate and mistaking alarm rate. The conclusion indicated that using the pattern classification method is possible to achieve the quite good effect in the detector critical partial value.