44 research outputs found
Novelty detection for long-term diagnostic data with Gaussian and non-Gaussian disturbances using a support vector machine
No full textIn condition monitoring lack of properly balanced data sets with faulty and healthy cases makes proper condition recognition very challenging. In many cases, one may have good condition data only as the machine is unique and there is no other example. This issue is addressed by proposing a support vector machine for novelty detection applied to health index data. In this scheme, the moving window approach has been utilized in which the simple statistical parameterization of the data is carried out. Then the model in the multidimensional (mD) space is constructed whose shape is defined by an estimated hypersphere border. If the data lies inside the border then it can be used to re-train the model. Whereas if it is outside the border then it cannot be recognized as a healthy case. The size of the mD hypersphere (for m = 2) describes the location of the good-condition data cloud as a potential feature. If the size of the data cloud is growing, it means more dispersion of the data. The efficiency of the method is tested on simulated and well-known real data sets having Gaussian and non-Gaussian disturbances.</p
Application of Machine Learning Tools for Long-Term Diagnostic Feature Data Segmentation
No full textIn this paper, a novel method for long-term data segmentation in the context of machine health prognosis is presented. The purpose of the method is to find borders between three data segments. It is assumed that each segment contains the data that represent different statistical properties, that is, a different model. It is proposed to use a moving window approach, statistical parametrization of the data in the window, and simple clustering techniques. Moreover, it is found that features are highly correlated, so principal component analysis is exploited. We find that the probability density function of the first principal component may be sufficient to find borders between classes. We consider two cases of data distributions, Gaussian and α-stable, belonging to the class of non-Gaussian heavy-tailed distributions. It is shown that for random components with Gaussian distribution, the proposed methodology is very effective, while for the non-Gaussian case, both features and the concept of moving window should be re-considered. Finally, the procedure is tested for real data sets. The results provided here may be helpful in understanding some specific cases of machine health prognosis in the presence of non-Gaussian noise. The proposed approach is model free, and thus it is universal. The methodology can be applied for any long-term data where segmentation is crucial for the data processing
Spin-dependent energy distribution of B-hadrons from polarized top decays considering the azimuthal correlation rate
No full textAbstractBasically, the energy distribution of bottom-flavored hadrons produced through polarized top quark decays t(↑)→W++b(→Xb), is governed by the unpolarized rate and the polar and the azimuthal correlation functions which are related to the density matrix elements of the decay t(↑)→bW+. Here we present, for the first time, the analytical expressions for the O(αs) radiative corrections to the differential azimuthal decay rates of the partonic process t(↑)→b+W+ in two helicity systems, which are needed to study the azimuthal distribution of the energy spectrum of the hadrons produced in polarized top decays. These spin-momentum correlations between the top quark spin and its decay product momenta will allow the detailed studies of the top decay mechanism. Our predictions of the hadron energy distributions also enable us to deepen our knowledge of the hadronization process and to test the universality and scaling violations of the bottom-flavored meson fragmentation functions
A pluriversal conversation about decolonial research methods and methodologies
No full textIn this paper, I evaluate the conversation about decolonial research methods and methodologies offered by the authors of this special issue from the position of a learner. I argue that their exchanges have two achievements: first, they challenge us to engage in a more critical discussion of decolonial research so that we may confront its tensions and paradoxes in a clear-eyed manner, and, second, they provide those who are seeking conceptual clarity meaningful taxonomies and historical overviews that make good sense of the field. However, unresolved conceptual and theoretical tensions amongst the authors ensure more contestation rather than the new coherence that the initiating author, Leon Moosavi, is aiming for.Global Challenges (FGGA
‘But you’re white’: An autoethnography of whiteness and white privilege in East Asian universities
No full textIt is well established within the field of Critical Whiteness Studies that white privilege routinely materialises in Western universities. Yet, even though a third wave of Critical Whiteness Studies is increasingly focussing on whiteness in non-Western contexts, there has been insufficient attention toward whether white privilege also exists in East Asian universities. This article seeks to explore this issue by offering an autoethnography in which the author, a mixed-race academic who is racialised as white on some occasions and as a person of colour on others, critically interrogates whiteness in East Asian higher education. It is argued that those who are racialised as white are privileged in East Asian universities and may even seek to actively sustain this. In departing from the dominant understanding of whiteness as always-and-only privileging, this article also explores the extent to which white academics in East Asia may also be disadvantaged by their whiteness
Maximum power point tracking under realistic operating conditions
No full textThe process of tracking the Maximum Power Point (MPP), known as MPPT, becomes problematic under realistic operating conditions due to the potential for there to be more than one local maxima. A very detailed physics based model has been developed for a PV module (in this application a PV roof tile) using the Orcad platform for PSpice. This model is unusual in that it properly represents partial module shading and cell temperature variation. The PV roof tile, based on polycrystalline silicon cells, comprises 18 series-connected cells. In the model, each cell is represented by a standard two-diode sub-model, for which different levels of radiation and cell temperature can be simulated to obtain a realistic overall I-V characteristic for the module. The model can be extended to model any reasonable number of PV roof tiles wired in series and parallel to form a roof array. The IV characteristics calculated in this way using PSpice will be validated using an outdoor PV roof test system located at the University of Strathclyde, Glasgow
Relationship between Leadership Styles and Organizational Performance by Considering Innovation in Manufacturing Companies of Guilan Province
No full textAbstractThe purpose of this research is to investigate the relationship between leadership styles (transformational and transactional styles) and organizational performance by considering innovation (exploratory and exploitative) in manufacturing companies of Guilan province. The present research is a descriptive study with an emphasis on the causal model in terms of execution and it is an applied research in terms of purpose. It is also a field research in terms of data collection. The statistical population of the research includes the manufacturing companies of Guilan province. The sample size was estimated to be 401 by using Cochran formula. Questionnaire was distributed among the managers of the manufacturing companies after confirming the validity and reliability of the research. In order to analyze the data and to test the hypotheses, the structural equation modeling was used by LISREL software. The test results show that there is a relationship between transformational leadership and exploratory innovation; but there is a negative relationship between transformational leadership and exploitative innovation. In addition, it was found that there is a negative relationship between transactional leadership and exploratory innovation and there is a relationship between transactional leadership and exploitative innovation
مفهوم شناسی»حیات«و جایگاه آن در سبک زندگی اسلامی
No full textهدف: از آنجا که «حیات» واژۀ کلیدی در «سبک زندگی» است، هدف این مقاله تبیین معنای آن از نگاه فلسفۀ اسلامی و جایگاه آن در «سبک زندگی اسلامی» است. روش: در گردآوریاطلاعاتازروش کتابخانهایودربررسیآنازروشتحلیلفلسفیاستفادهشدهاست. یافتهها: «حیات» از مفاهیم ثانویه فلسفی بوده که به آثار آن؛ یعنی رشد و نمو یا علم و قدرت تعریف شده است. «نفس» مبدء حیات است و نفس انسان در حیات دنیوی خود، دارای حیاتِ نباتی و حیوانی و انسانی بوده و موجودی انتخابگر است. نفس انسان با توجه به انتخابگر بودن و حرکت جوهریای که دارد، در مسیر ساختن خویش حرکت میکند که بر اساس آن سبک زندگی تعریف میشود. نتیجهگیری:در این نوشتار با توجه به تعریف «سبک زندگی»، که مؤلفۀ اصلی آن، اراده و اختیار انسان معرفی شده، نتیجهگیری شده است که سبک زندگی اولاً، فقط در حیات انسان مطرح میشود و در حیات خداوند و موجودات مجرد و همچنین در حیات حیوانات و نباتات مطرح نیست. ثانیاً، سبک زندگی فقط در آن بخش از زندگی انسان که ارادی و اختیاری است (حیات حیوانی و حیات انسانی) مطرح میشودObjectives:The aim of the present research is to analyze the concept of" life from the philosophical point of view and clarify its place in" islamic life style". Method: The method of the research is library and philosophical analysis method. Results: The results of the study indicate that "life" is one of the secondary concepts in philosophy which has been defined through its consequences and effects such as development and growth or science and power. "Ego" or "soul" (nafs) is the origin of life and the soul of human being in its physical life includes virtus animals' life, vegetative life and humanistic life and is a selector creature .since the soul of human being is selective and it's trans-substantial movement , it leads to self construction which life style is defined with. Conclusion: The author of the article concludes due to the definition of " life style" with the main component which is human determination or arbitrariness , the life style is : 1- defined in the life of human being and is not a subject of gods life or immaterial or animals .2- life style is just related to that part of human being's life which is optional and arbitrariness ( animals' life and humanistic life)
Analytical study of the seismic performance of all-steel buckling-restrained braces with H-shaped cores
No full textThe seismic performance of an H-shaped core buckling-restrained brace (HBRB) is evaluated through detailed finite element analysis. The numerical model is validated against available experimental data and a parametric study is carried out to investigate the effect of influential parameters on the cyclic behavior and failure modes of HBRB. Several design parameters including the yielding length ratio, the constrained length, the presence of stiffeners and their thicknesses, the length of the transition region and the gap size are considered in the parametric investigation. Based on the analysis results reducing the yielding length of HBRB increases its post-yield stiffness and the axial strain and stress of the H-section core. Since buckling of the unconstrained region was observed in HBRBs with insufficient stiffener thickness, an analytical method is proposed for evaluating the sufficiency of stiffeners by estimating the critical buckling load of HBRB as a three-segment stepped compression member.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
Thermodynamic analysis of zinc ferrite (ZnFe<sub>2</sub>O<sub>4</sub>) formation inside the HIsarna off-gas system
No full textHIsarna reactor is characterized by a high raw materials versatility and is therefore attractive for processing secondary iron sources. Among the materials that can be recycled through HIsarna, zinc-bearing material has drawn a special attention. Based on the plant data, once dust-containing Zinc was injected into the main reactor, a final collected dust with a zinc content of 16% was achieved which opened up possibilities of higher enrichment for direct reuse in Zn smelting as a secondary source and an alternative for Zn ore (the primary source). However Zn vapor can react with iron oxide to form zinc ferrite (ZnFe2O4), which is an undesired product. Hence, the main focus of this study is to minimize the formation of ZnFe2O using thermodynamic (FactSage) and computational fluid dynamic tools. After detecting regions with high potential of ZnFe2O4 formation, proper geometrical and operational modifications of the off-gas system is proposed to minimize the formation of zinc ferrite.Team Yongxiang YangTeam Erik Offerma
