This paper analyzes the measurement error, caused by the position of the current-carrying conductor, of a circular array of magnetic sensors for current measurement. The circular array of magnetic sensors is an effective approach for AC or DC non-contact measurement, as it is low-cost, light-weight, has a large linear range, wide bandwidth, and low noise. Especially, it has been claimed that such structure has excellent reduction ability for errors caused by the position of the current-carrying conductor, crosstalk current interference, shape of the conduction cross-section, and the Earth’s magnetic field. However, the positions of the current-carrying conductor—including un-centeredness and un-perpendicularity—have not been analyzed in detail until now. In this paper, for the purpose of having minimum measurement error, a theoretical analysis has been proposed based on vector inner and exterior product. In the presented mathematical model of relative error, the un-center offset distance, the un-perpendicular angle, the radius of the circle, and the number of magnetic sensors are expressed in one equation. The comparison of the relative error caused by the position of the current-carrying conductor between four and eight sensors is conducted. Tunnel magnetoresistance (TMR) sensors are used in the experimental prototype to verify the mathematical model. The analysis results can be the reference to design the details of the circular array of magnetic sensors for current measurement in practical situations.

A huge amount of information is spread in the network, and each kind of information contains the possibility of influencing public opinion. However, considering the number of reasons, it is not realistic to review the information transmitted by users. It is of practical value to both the development of enterprises and the work of the government to analyze the network contents that are likely to become popular information in the future by means of prediction. This paper makes an in-depth study on the relevant theories of online community user influence and network content popularity, and summarizes the methods and shortcomings of domestic and foreign mainstream research. On this basis, the user influence measurement model based on PageRank and LDA and the post popularity measurement model based on neural network are constructed. In this paper, the Topic factor is innovatively brought into the measuring range of user influence, and the topic-relation Rank measurement model of user influence is established based on PageRank. Aiming at Baidu Tieba, the article uses crawlers to obtain real data and conduct experiments. The results show that the user influence measurement model integrates three influencing factors, namely user, network topology and text topic, so the model has a good measuring effect.

In order to have a more comprehensive understanding of the application of different detection methods to capacitive equipment in the power system, the data of serious defects and faults of capacitive equipment in a province (city) power company from 2005 to 2014 were collected. The detection methods were divided into three categories: live detection, power-off test and patrol inspection. And makes statistics of the number, proportion and efficiency of the defects detected by different detection methods. It also counts the number of faults in the equipment, and calculate the change of failure rate caused by canceling the power-off test. Through these data, this paper analyzes the feasibility of using live detection instead of power-off test and make a comprehensive summary of the application status of three types of detection.

This paper analyzes the measurement error, caused by the position of the current-carrying conductor, of circular array of magnetic sensors for current measurement. The circular array of magnetic sensors is an effective approach for AC or DC non-contact measurement, as its low cost, large linear range, wide bandwidth, light weight and low noise. Especially it has claimed that such structure has the excellent reduction ability for the errors caused by the position of the current-carrying conductor, crosstalk current interference, shape of the conduction cross section and the earth magnetic field. However, the positions of the current-carrying conductor, including un-center and un-perpendicularity, has not analyzed in detail until now. In this paper, the theoretical analysis has been proposed based on vector inner and exterior product. In the presented mathematical model of relative error, the un-center offset distance, the un-perpendicular angle, the radius of the circle and the number of the magnetic sensor are expressed in one equation. The comparison of the relative error caused by the position of the current-carrying conductor between four and eight sensors is conducted. The Tunnel Magnetoresistance (TMR) sensors are used in the experimental prototype to verify the mathematical model. The analysis results can be the reference to design the detail of circular array of magnetic sensors for current measurement in practical situation.