374 research outputs found

    A novel expert system of fault diagnosis based on vibration for rotating machinery

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    To avoid significant losses of rotating machinery which works in high-speed and heavy load for long-term, it is necessary to find faults by means of vibrations. A novel expert system of vibration fault diagnosis based on artificial intelligence for rotating machinery was presented, in which a equipment property database is established to obtain the symptom frequencies of fault of components, such as rotor, roll bearing and gear box, of equipment, so any fault can be found quickly and effectively and then the losses of fault can be reduced and further eliminated. The diagnostic reasoning engine of the system combined the forward reasons method and the forward-backward hybrid reasons method. It is proved by the diagnostic examples that the system is reasonable and scientific in structure, quick and reliable in diagnosis

    An Analysis of Communicative Language Teaching Methodology and Its Application on Language Learning in China

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    Abstract: This paper mainly introduces the prevalent methodology which is known as Communicative Language Teaching, or CLT. The origins and evolution of the methodology are firstly introduced. Through analyzing its major principles and approaches, the paper examines how the CLT methodology influences approaches to language teaching today. From the analysis, the CLT methodology does help to raise language learners’ interests and advance their learning efficiency. However, in the process of applying the CLT method in English classrooms of China, it is constrained by some factors in terms of the different language and culture backgrounds. Thus the paper illustrates these problems which lead to the limitations of CLT application in Chinaand also provides the solutions on how to integrate traditional teaching methodologies with communicative language teaching method in English classes in China

    Information-Theoretic Measures for Objective Evaluation of Classifications

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    This work presents a systematic study of objective evaluations of abstaining classifications using Information-Theoretic Measures (ITMs). First, we define objective measures for which they do not depend on any free parameter. This definition provides technical simplicity for examining "objectivity" or "subjectivity" directly to classification evaluations. Second, we propose twenty four normalized ITMs, derived from either mutual information, divergence, or cross-entropy, for investigation. Contrary to conventional performance measures that apply empirical formulas based on users' intuitions or preferences, the ITMs are theoretically more sound for realizing objective evaluations of classifications. We apply them to distinguish "error types" and "reject types" in binary classifications without the need for input data of cost terms. Third, to better understand and select the ITMs, we suggest three desirable features for classification assessment measures, which appear more crucial and appealing from the viewpoint of classification applications. Using these features as "meta-measures", we can reveal the advantages and limitations of ITMs from a higher level of evaluation knowledge. Numerical examples are given to corroborate our claims and compare the differences among the proposed measures. The best measure is selected in terms of the meta-measures, and its specific properties regarding error types and reject types are analytically derived.Comment: 25 Pages, 1 Figure, 10 Table

    Calibration of the in-orbit center-of-mass of TaiJi-1

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    Taiji program is a space mission aiming to detect gravitational waves in the low frequency band. Taiji-1 is the first technology demonstration satellite of the Taiji Program in Space, with the gravitational reference sensor (GRS) serving as one of its key scientific payloads. For accurate accelerometer measurements, the test-mass center of the GRS must be positioned precisely at the center of gravity of the satellite to avoid measurement disturbances caused by angular acceleration and gradient. Due to installation and measurement errors, fuel consumption during in-flight phase, and other factors, the offset between the test-mass center and the center-of-mass (COM) of the satellite can be significant, degrading the measurement accuracy of the accelerometer. Therefore, the offset needs to be estimated and controlled within the required range by the center-of-mass adjustment mechanism during the satellite's lifetime. In this paper, we present a novel method, the Extended Kalman Filter combined with Rauch-Tung-Striebel Smoother, to estimate the offset, while utilizing the chi-square test to eliminate outliers. Additionally, the nonlinear Least Squares estimation algorithm is employed as a crosscheck to estimate the offset of COM. The two methods are shown to give consistent results, with the offset estimated to be dx≈dx \approx −-0.190.19 mm, dy≈0.64dy \approx 0.64 mm, and dz≈dz \approx −-0.820.82 mm. The results indicate a significant improvement on the noise level of GRS after the COM calibration, which will be of great help for the future Taiji program.Comment: 8 pages, 9 figure

    Detection of Freezing of Gait Using Template-Matching-Based Approaches

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    Every year, injuries associated with fall incidences cause lots of human suffering and assets loss for Parkinson’s disease (PD) patients. Thereinto, freezing of gait (FOG), which is one of the most common symptoms of PD, is quite responsible for most incidents. Although lots of researches have been done on characterized analysis and detection methods of FOG, large room for improvement still exists in the high accuracy and high efficiency examination of FOG. In view of the above requirements, this paper presents a template-matching-based improved subsequence Dynamic Time Warping (IsDTW) method, and experimental tests were carried out on typical open source datasets. Results show that, compared with traditional template-matching and statistical learning methods, proposed IsDTW not only embodies higher experimental accuracy (92%) but also has a significant runtime efficiency. By contrast, IsDTW is far more available in real-time practice applications

    Tryptophan-rich domains of Plasmodium falciparum SURFIN4.2 and Plasmodium vivax PvSTP2 interact with membrane skeleton of red blood cell

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    Additional file 1: Table S1. Primers for PCR amplification and plasmid construction

    Design and Application of Exclusive Service App for Rural Elderly

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    With the further advancement of rural development and the rapid development of mobile Internet, rural service apps have gradually become an important means of promoting rural economic development and improving farmers’ production and living standards. At present, a number of service-type apps with wide applications in the field of rural services have emerged, such as “Planting Master”, “Farming Network”, “Rural Taobao”, etc. However, these apps do not pay special attention to special groups, but only target the majority of young people and office workers. However, these apps do not pay special attention to special groups, but only target the majority of young people and office workers. In order to fill this gap, we have designed a software called Nong’e Tong, which is specially designed for the elderly and other special groups. The software has a simple and beautiful interface, and is easy to use. It not only provides a lot of special functions, but also can link the elderly’s cell phone with their children’s cell phones to check the health and safety of the elderly at any time. Compared to other software, the application has special features for seniors to ensure that they can use the application easily and quickly

    Lysine-specific demethylase 5C promotes hepatocellular carcinoma cell invasion through inhibition BMP7 expression

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    The primers used for the amplification of the indicated genes.(DOCX 17 kb
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