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The power grid is an important connection between power sources and users, responsible for supplying and distributing electric energy to users. Modern power grids are widely distributed and large in scale, and their security faces new problems and challenges. Information entropy theory is an objective weighting method that compares the information order of each evaluation index to judge the weight value. With the wide application of entropy theory in various disciplines, the subject of introducing entropy into the power system has been gradually concerned. This article aims to study the smart terminal security technology of the power grid perception layer based on information entropy data mining. This article analyzes its related methods and designs a smart terminal for the power grid. On this basis, a data analysis platform is built and a safety plan is designed. The result is that the average absolute error, root mean square error, average absolute percentage error, and mean square error of the platform's power load forecast are 1.58, 1.96, 8.2%, and 3.93, respectively. These error values are within the ideal range, and the data processing ability is strong. The packet loss rate of the adversary's eavesdropping was tested, and the average packet loss rates at locations a, b, c, and d were 1.05, 1.2, 1.81, and 2.2%, respectively. Data packets will be definitely lost, so the platform is highly secure.

In speaker recognition systems, feature extraction is a challenging task under environment noise conditions. To improve the robustness of the feature, we proposed a multiscale chaotic feature for speaker recognition. We use a multiresolution analysis technique to capture more finer information on different speakers in the frequency domain. Then, we extracted the speech chaotic characteristics based on the nonlinear dynamic model, which helps to improve the discrimination of features. Finally, we use a GMM-UBM model to develop a speaker recognition system. Our experimental results verified its good performance. Under clean speech and noise speech conditions, the ERR value of our method is reduced by 13.94% and 26.5% compared with the state-of-the-art method, respectively.

Formative assessment (FA) has enjoyed much popularity in educational assessment in recent years, especially for the teaching of writing. However, the application of FA in academic English writing (AEW) has rarely been studied. Employing both quantitative and qualitative methods, this study is designed to explore the effectiveness of FA in the process approach of AEW for EFL learners in China. Results from a T-test show that there is a significant difference in students' performance between the experimental and the control group. Meanwhile, the results of repeated measures ANOVA demonstrate significant difference among the three drafts produced by the participants in the experimental group. Qualitative studies also show that feedback provided by both peers and the teacher is treated seriously by most learners, which contributes to the gradual improvement of their writing. The results of the study suggest that FA may be more effective than summative assessment (SA) for the improvement of learners' AEW ability.

Background Population aging is a major challenge in the global healthcare field. Due to pathological and physiological changes in ageing skin, skin injuries are highly prevalent in older population. And epidemiological studies on skin injuries in this population has become a research hotspot recently. Objective To examine the prevalence and epidemiological characteristics of three types of skin injuries 〔pressure injuries (PI) , incontinence-associated dermatitis (IAD) and skin tears (ST) 〕in elderly inpatients using a multicenter cross-sectional study, providing a basis for formulating strategies for the prevention of skin injuries in older people. Methods A multicenter study was carried out in 52 hospitals selected from 16 provinces, two autonomous regions and two municipalities of China, from which 1 067 nurses who had completed the online homogenization training conducted by our research group and passed the relevant examination were selectedas investigators. Every 2-3 nurses were divided into a investigation group. Eligible older inpatients were selected as participants. Full body skin examination for screening skin injuries was conducted in participants in each hospital by nurses using the same tools and methods. PI, IAD and ST were defined and classified by relevant international guideline or expert consensus, respectively. Then demographics, length of stay (LOS) , chronic disease history, use of medications in the past month, living independence and risk of PI assessed by the Braden Scale of the participants were collected. After that, two nurses of each group signed to confirm the results, and uploaded to https://www.wjx.cn. SPSS 22.0 was used for statistical analysis. Results A total of 14 675 elderly inpatients were investigated, and all of them responded effectively (100.0%) . The respondents had an average age of (73.5±9.0) years and a median LOS of 7 (4, 13) days, among whom 56.3% (8 262/14 675) were men, and 43.7% (6 413/14 675) were women; 95.5% (14 020/14 675) were Han people, and 4.5% (655/14 675) were 19 ethnic minorities. The overall prevalence of the three types of skin injuries was 6.0% (881/14 675) , of which the prevalence of PI, IAD, ST and at least two types of skin injuries was 3.3% (484/14 675) , 1.4% (199/14 675) , 0.8% (110/14 675) and 0.6% (88/14 675) , respectively. Epidemiologic characteristics: Han people had higher prevalence of skin injuries compared with ethnic minorities (6.2% vs 2.9%, P=0.001) . Eighty-year-olds had higher prevalence of skin injuries than 71-80-year-old (10.2% vs 6.1%, P

The Doppler-spread problem is commonly encountered in space target observation scenarios using ground-based radar when prolonged coherent integration techniques are utilized. Even when the translational motion is accurately compensated, the phase resulting from changes in the target observation attitude (TOA) still leads to extension of the target's echo energy across multiple Doppler cells. In particular, as the TOA change undergoes multiple cycles within a coherent processing interval (CPI), the Doppler spectrum spreads into equidistant sparse line spectra, posing a substantial challenge for target detection. Aiming to address such problems, we propose a generalized likelihood ratio test based on overlapping group shrinkage denoising and order statistics (OGSos-GLRT) in this study. First, the Doppler domain signal is denoised according to its equidistant sparse characteristics, allowing for the recovery of Doppler cells where line spectra may be situated. Then, several of the largest Doppler cells are integrated into the GLRT for detection. An analytical expression for the false alarm probability of the proposed detector is also derived. Additionally, a modified OGSos-GLRT method is proposed to make decisions based on an increasing estimated number of line spectra (ENLS), thus increasing the robustness of OGSos-GLRT when the ENLS mismatches the actual value. Finally, Monte Carlo simulations confirm the effectiveness of the proposed detector, even at low signal-to-noise ratios (SNRs). [ABSTRACT FROM AUTHOR]