The integration of low-voltage data collection system is relatively high, and there are some problems such as long distance between nodes. Therefore, while testing the operation reliability of the system, it is often difficult to analyze and the accuracy is low because of power consumption. Based on that, a reliability analysis method for low-voltage centralized reading system based on LoRa technology is proposed in this paper. Under LoRa framework protocol, the evaluation index of system reliability is defined, and the running state of the system is determined by calculating the state transition rate, the stationary state probability and the instantaneous state of the components. With this basis, the load carrying capacity of each node and the risk of voltage collapse are calculated respectively. Through setting up control group and experimental group to carry out detailed empirical analyses, the reliability analysis results of the system are obtained. Through comparison, it is found that the average analysis accuracy of the system operation reliability analysis method designed is 25% higher than that of the traditional method.

Most techniques of DoS attack are single-model, which have the disadvantages of low attack efficiency and weak adaptability. This paper presents a blended-mode DoS attack mode and we focus on the analysis of the efficiency of this mode. In this mode, we combine different DoS attack modes to attack the target at the same time for increasing theefficiency. In this paper, through some experiments we verify the high efficiency of this mode.

DC power supply is usually obtained by rectification, filtering, voltage stabilization and other processes of municipal electricity. Due to the incomplete rectification or the existence of switching power supply, the output DC stability is superimposed with AC components, called ripple. The generation of ripple will bring noise, reduce the efficiency of power supply and affect the normal operation of the system. Strong ripple will cause the generation of surge voltage or current, and burn down electrical appliances and other equipment. This paper designs a detection device which can quickly and efficiently detect the ripple of carrier power supply. The experimental results show that the design system can help testers quickly judge whether the ripple of carrier module power supply meets the ripple voltage limit stipulated by Southern Power Grid Corporation, and is used to detect the ripple of power supply. Testing provides a new method of implementation.