38,136 research outputs found

    Motor current signal analysis using a modified bispectrum for machine fault diagnosis

    Get PDF
    This paper presents the use of the induction motor current to identify and quantify common faults within a two-stage reciprocating compressor. The theoretical basis is studied to understand current signal characteristics when the motor undertakes a varying load under faulty conditions. Although conventional bispectrum representation of current signal allows the inclusion of phase information and the elimination of Gaussian noise, it produces unstable results due to random phase variation of the sideband components in the current signal. A modified bispectrum based on the amplitude modulation feature of the current signal is thus proposed to combine both lower sidebands and higher sidebands simultaneously and hence describe the current signal more accurately. Based on this new bispectrum a more effective diagnostic feature namely normalised bispectral peak is developed for fault classification. In association with the kurtosis of the raw current signal, the bispectrum feature gives rise to reliable fault classification results. In particular, the low feature values can differentiate the belt looseness from other fault cases and discharge valve leakage and intercooler leakage can be separated easily using two linear classifiers. This work provides a novel approach to the analysis of stator current for the diagnosis of motor drive faults from downstream driving equipment

    Blind estimation of reverberation time in classrooms and hospital wards

    Get PDF
    This paper investigates blind Reverberation Time (RT) estimation in occupied classrooms and hospital wards. Measurements are usually made while these spaces are unoccupied for logistical reasons. However, occupancy can have a significant impact on the rate of reverberant decay. Recent work has developed a Maximum Likelihood Estimation (MLE) method which utilises only passively recorded speech and music signals, this enables measurements to be made while the room is in use. In this paper the MLE method is applied to recordings made in classrooms during lessons. Classroom occupancy levels differ for each lesson, therefore a model is developed using blind estimates to predict the RT for any occupancy level to within ±0.07s for the mid-frequency octave bands. The model is also able to predict the effective room and per person absorption area. Ambient sound recordings were also carried out in a number of rooms in two hospitals for a week. Hospital measurements are more challenging as the occurrence of free reverberant decay is rarer than in schools and the acoustic conditions may be non-stationary. However, by gaining recordings over a period of a week, estimates can be gained within ±0.07 s. These estimates are representative of the times when the room contains the highest acoustic absorption. In other words when curtains are drawn, there are many visitors or perhaps a window may be open

    Implementasi Pembelajaran Guided Discovery pada Materi Fotosintesis untuk Meningkatkan Hasil Belajar Siswa SMP Kelas VII

    Full text link
    Penelitian ini bertujuan untuk mendeskripsikan keterlaksanaan pembelajaran, peningkatan hasil belajar siswa, dan respons siswa terhadap model pembelajaran guided discovery pada materi fotosintesis kelas VII SMPN. Jenis penelitian pre experimental design dengan menggunakan satu kelas perlakuan. Subjek penelitian ini adalah siswa kelas VII SMPN 1 Cerme tahun pelajaran 2015/2016 yang berjumlah 32 siswa dan rancangan penelitian menggunakan one group pre-test and post-test design. Teknik pengumpulan data dalam penelitian ini menggunakan metode observasi, tes, dan angket Hasil data penelitian menunjukkan bahwa: (1) Keterlaksanaan model pembelajaran guided discovery memperoleh persentase keterlaksanaan sebesar 97,46% dengan kriteria sangat baik. (2) Penerapan pembelajaran guided discovery dapat meningkatkan hasil belajar siswa yang ditandai dengan hasil perhitungan uji N-Gain menunjukkan adanya peningkatan hasil belajar sebesar 0,6489 dengan kategori sedang. (3) Siswa memberikan respon sangat baik terhadap implementasi model pembelajaran guided discovery dengan diperoleh persentase sebesar 97,27% dengan kriteria sangat baik.   Kata kunci : guided discovery, hasil belajar , fotosintesi

    Development of a Consensus Statement for the Definition, Diagnosis, and Treatment of Acute Exacerbations of Idiopathic Pulmonary Fibrosis Using the Delphi Technique.

    Get PDF
    © 2015, The Author(s).Introduction: There is a lack of agreed and established guidelines for the treatment of acute exacerbations of idiopathic pulmonary fibrosis (AE-IPF). This reflects, in part, the limited evidence-base underpinning the management of AE-IPF. In the absence of high-quality evidence, the aim of this research was to develop a clinician-led consensus statement for the definition, diagnosis and treatment of AE-IPF. Methods: A literature review was conducted to obtain published material on the definition and treatment of AE-IPF. The results of this review were circulated to an online panel of clinicians for review. Statements were then shared with ten expert respiratory clinicians who regularly treat patients with IPF. A Delphi technique was then used to develop a consensus statement for the definition, diagnosis and treatment of AE-IPF. During the first round of review, clinicians rated the clarity of each statement, the extent to which the statement should be included and provided comments. In two subsequent rounds of review, clinicians were provided with the group median inclusion rating for each statement, and any revised wording of statements to aid clarity. Clinicians were asked to repeat the clarity and inclusion ratings for the revised statements. Results: The literature review, online panel discussion, and face-to-face meeting generated 65 statements covering the definition, diagnosis, and management of AE-IPF. Following three rounds of blind review, 90% of clinicians agreed 39 final statements. These final statements included a definition of AE-IPF, approach to diagnosis, and treatment options, specifically: supportive measures, use of anti-microbials, immunosuppressants, anti-coagulants, anti-fibrotic therapy, escalation, transplant management, and long-term management including discharge planning. Conclusion: This clinician-led consensus statement establishes the ‘best practice’ for the management and treatment of AE-IPF based on current knowledge, evidence, and available treatments. Funding: Boehringer Ingelheim Ltd., Bracknell, West Berkshire, UK

    Clinical challenges in the co-management of diabetes mellitus and tuberculosis in southern Africa

    Get PDF
    Over the past 20 years, tuberculosis incidence in southern Africa has increased at an alarming rate, fuelled primarily by the human immunodeficiency virus epidemic. The emerging prevalence of diabetes mellitus in the region represents a new threat to tuberculosis control. The intersecting double burden is a cause for concern since diabetes mellitus increases the risk of tuberculosis and results in poor treatment outcomes. This review article discusses the evidence of a causal association between these two conditions, and examines the numerous clinical challenges that relate to tuberculosis and diabetes mellitus co-management. Diabetes is associated with a more advanced age and body weight in patients with tuberculosis, although not with a specific clinical presentation of tuberculosis. Rifampicin adversely alters glycaemic control by lowering the concentrations of most oral antidiabetic drugs. Poor glycaemic control, possibly exacerbated by tuberculosis and anti-tuberculous therapy, is an important contributing factor to tuberculosis case fatality and relapse. Clinicians need to be aware of these clinical and pharmacological challenges when co-managing these complex diseases.Keywords: diabetes, tuberculosis, rifampicin, co-management, southern Afric

    Emergency hospital admissions with hypoglycaemia: analysis of hospital episode statistics in England and a UK tertiary hospital electronic health record

    Get PDF

    Analyzing Digital Image by Deep Learning for Melanoma Diagnosis

    Get PDF
    Image classi cation is an important task in many medical applications, in order to achieve an adequate diagnostic of di erent le- sions. Melanoma is a frequent kind of skin cancer, which most of them can be detected by visual exploration. Heterogeneity and database size are the most important di culties to overcome in order to obtain a good classi cation performance. In this work, a deep learning based method for accurate classi cation of wound regions is proposed. Raw images are fed into a Convolutional Neural Network (CNN) producing a probability of being a melanoma or a non-melanoma. Alexnet and GoogLeNet were used due to their well-known e ectiveness. Moreover, data augmentation was used to increase the number of input images. Experiments show that the compared models can achieve high performance in terms of mean ac- curacy with very few data and without any preprocessing.Universidad de MĂĄlaga. Campus de Excelencia Internacional AndalucĂ­a Tech

    Exploring the Referral and Usage of Science Fiction in HCI Literature

    Full text link
    Research on science fiction (sci-fi) in scientific publications has indicated the usage of sci-fi stories, movies or shows to inspire novel Human-Computer Interaction (HCI) research. Yet no studies have analysed sci-fi in a top-ranked computer science conference at present. For that reason, we examine the CHI main track for the presence and nature of sci-fi referrals in relationship to HCI research. We search for six sci-fi terms in a dataset of 5812 CHI main proceedings and code the context of 175 sci-fi referrals in 83 papers indexed in the CHI main track. In our results, we categorize these papers into five contemporary HCI research themes wherein sci-fi and HCI interconnect: 1) Theoretical Design Research; 2) New Interactions; 3) Human-Body Modification or Extension; 4) Human-Robot Interaction and Artificial Intelligence; and 5) Visions of Computing and HCI. In conclusion, we discuss results and implications located in the promising arena of sci-fi and HCI research.Comment: v1: 20 pages, 4 figures, 3 tables, HCI International 2018 accepted submission v2: 20 pages, 4 figures, 3 tables, added link/doi for Springer proceedin
    • 

    corecore