A new differentially fed frequency reconfigurable antenna adopting proximity-coupling feeding for WLAN and sub-6-GHz 5G applications is proposed in this paper. It consists of two substrates that are separated by a 2.5-mm-thick air gap. By configuring the four p-in diode switches arranged on the two substrates, the excitation of the radiating patch and the length of the feed-lines can be controlled, and then, two different operating frequency bands can be obtained. The experiments indicate that the designed antenna can be switched between two states operating at 2.45-and 3.50-GHz band, respectively. Good agreement between the simulated and measured results is achieved, and the radiation patterns and gains are similar for the two states. The proposed antenna is a good candidate for WLAN (2.45 GHz) and sub-6-GHz 5G (3.50 GHz) applications. INDEX TERMS Differentially-fed, frequency reconfigurable antenna, PIN diode switch.

The bearing is the key component of rotating machinery, and its performance directly determines the reliability and safety of the system. Data-based bearing fault diagnosis has become a research hotspot. Naive Bayes (NB), which is based on independent presumption, is widely used in fault diagnosis. However, the bearing data are not completely independent, which reduces the performance of NB algorithms. In order to solve this problem, we propose a NB bearing fault diagnosis method based on enhanced independence of data. The method deals with data vector from two aspects: the attribute feature and the sample dimension. After processing, the classification limitation of NB is reduced by the independence hypothesis. First, we extract the statistical characteristics of the original signal of the bearings effectively. Then, the Decision Tree algorithm is used to select the important features of the time domain signal, and the low correlation features is selected. Next, the Selective Support Vector Machine (SSVM) is used to prune the dimension data and remove redundant vectors. Finally, we use NB to diagnose the fault with the low correlation data. The experimental results show that the independent enhancement of data is effective for bearing fault diagnosis.

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This paper presents a method of estimating channel parameters in wireless communications using space-time block coding (STBC). After reviewing the concept of STBC, the system model of radio communication with STBC is described and the estimation method is derived. System performances have been simulated using MATLAB. The results of the simulations show that the proposed algorithm of channel estimation is practicable and effective as there is only little discrepancy between the performances using the estimated and known channel parameters.

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Grey correlation analysis uses grey correlations to describe the strength, magnitude, and order of relationships among factors. The data sequence of the drmined data is used as a reference data string, and the data sequence matrix of each influence factor is used as a control data matrix to calculate the correlation between the data sequence and the reference of each factor in the control data matrix. The basic idea of quantitatively measuring the correlation between each factor and the object is to determine the similarity between the reference data sequence and the shape of multiple comparison data sequences and to determine whether the connection is strong. It reflects the degree of correlation between curves. In this paper, we examine the problem of evaluating the quality of undergraduate education by multiple indicators and establish a comprehensive evaluation model of the quality of undergraduate education in the 13 prefecture level cities by using the grey correlation analysis. The correlation coefficient of each index was obtained by the grey correlation analysis, the correlation number of each index was analyzed and ranked, and finally the improvement of the number of “advanced teachers” and the education of 13 prefectures were reduced as much as possible.

Using infrared spectrum detective device, we experiment on Neiguan, Laogong and Hegu acupoints of seven adult volunteers as well as contrastive points beside ones. We get 63 infrared spectrums. The experiment outcome tells us that the differences of the intensities among individuals are great, and so are the differences between acupoint and non-acupoint areas. However, the differences of spectral character are small, which indicates that infrared radiations of human body are based on the same biophysical fundament.Human body is an infrared source, which emits continuous infrared spectrum ranging from 1 to 30 m. If the human body is assumed as a point of light source, its radiation peak is at about 10 m. We know, according to physics, that objects whose temperatures are over absolute zero are all infrared radiative. Such researches as human body thermoradiation are very much reported internally and externally. One typical example is the observation of the infrared radiation locuses in human body surface which are similar to the routes of energy channels, as indicated by the infrared imaging system. However, millions of biochemical reactions, which continuously emit infrared photons through human body surface, are included in the human physiology, and the conditions which can activate radiation also exist. Experimental researches also show the close relation between the function of energy channels and the internal infrared transmission. Therefore, to further the studies of infrared radiation of energy channels and its law of propagation, and to select methods of examinations, it is of great importance to thoroughly examine the spectral character of infrared radiation of localareas in human body surface and to obtain basic data of infrared radiation of acupoint areas. Because human body infrared radiation is quite weak and the area to be examined is less than 1 cm 2 , high sensitivity of experimental conditions and equipment is requisite; however, no such reports have been seen. This note is to report some of our recent work. Using a set of high sensitive infrared spectrum detective devices, we have recorded some infrared spectrums of acupoints such as Neiguan and their contrastive points in vicinity, and have analyzed the character preliminarily.

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