2,349 research outputs found

    Medically Relevant Criteria used in EEG Compression for Improved Post-Compression Seizure Detection

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    Biomedical signals aid in the diagnosis of different disorders and abnormalities. When targeting lossy compression of such signals, the medically relevant information that lies within the data should maintain its accuracy and thus its reliability. In fact, signal models that are inspired by the bio-physical properties of the signals at hand allow for a compression that preserves more naturally the clinically significant features of these signals. In this paper, we illustrate this through the example of EEG signals; more specifically, we analyze three specific lossy EEG compression schemes. These schemes are based on signal models that have different degrees of reliance on signal production and physiological characteristics of EEG. The resilience of these schemes is illustrated through the performance of seizure detection post compression.Comment: This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessibl

    Detection of Sentiment Provoking Events in Social Media

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    Social media has become one of the main sources of news and events due to its ability to disseminate and propagate information very fast and to a large population. Social media platforms are widely accessible to the population making it difficult to extract relevant information from the huge amount of posted data. In our study, we propose an algorithm that automatically detects events using strong sentiment classification and appropriate clustering techniques. We focus our study on a specific type of events that triggers strong sentiment among the public. Results show that the suggested methodology is able to identify important events, such as a mass shooting and plane crash, using a generalized and simple approach

    A Hybrid Active Filter Using the Backstepping Controller for Harmonic Current Compensation

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    This document presents a new hybrid combination of filters using passive and active elements because of the generalization in the use of non-linear loads that generate harmonics directly affecting the symmetry of energy transmission systems that influence the functioning of the electricity grid and, consequently, the deterioration of power quality. In this context, active power filters represent one of the best solutions for improving power quality and compensating harmonic currents to get a symmetrical waveform. In addition, given the importance and occupation of the transmission network, it is necessary to control the stability of the system. Traditionally, passive filters were used to improve energy quality, but they have endured problems such as resonance, fixed remuneration, etc. In order to mitigate these problems, a hybrid HAPF active power filter is proposed combining a parallel active filter and a passive filter controlled by a backstepping algorithm strategy. This control strategy is compared with two other methods, namely the classical PI control, and the fuzzy logic control in order to verify the effectiveness and the level of symmetry of the backstepping controller proposed for the HAPF. The proposed backstepping controller inspires the notion of stability in Lyapunov’s sense. This work is carried out to improve the performance of the HAPF by the backstepping command. It perfectly compensates the harmonics according to standards. The results of simulations performed under the Matlab/Simulink environment show the efficiency and robustness of the proposed backstepping controller applied on HAPF, compared to other control methods. The HAPF with the backstepping controller shows a significant decrease in the THD harmonic distortion rate

    Three essays on intellectual capital in Mexican SMEs

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    Cette thĂšse s’intĂ©resse Ă  la mesure du capital intellectuel (CI) ainsi que son impact sur les avantages compĂ©titifs de petites et moyennes entreprises (PME) au Mexique. La principale question de recherche est : Comment le capital intellectuel devrait-il ĂȘtre mesurĂ© et quel est son impact sur l’avantage compĂ©titif des PME au Mexique? Afin de rĂ©pondre Ă  la question de la recherche, le premier article offre une perspective mĂ©thodologique du CI. Dans cette revue, les limites des mĂ©thodes quantitatives utilisĂ©es lors de l’étude du CI sont soulevĂ©es. L’utilisation de la modĂ©lisation par Ă©quations structurelles est discutĂ©e et privilĂ©giĂ©e. Dans le deuxiĂšme article, un modĂšle de mesure adaptĂ© aux rĂ©alitĂ©s des PME mexicaines est proposĂ©. Les rĂ©sultats suggĂšrent que, le capital humain et le capital organisationnel sont cohĂ©rents avec les Ă©tudes prĂ©cĂ©dentes portant sur le CI dans les PME. Par contre, le capital externe prĂ©sente des caractĂ©ristiques uniques au contexte du Mexique. De plus, malgrĂ© les disparitĂ©s socio-Ă©conomiques entre les diffĂ©rentes rĂ©gions au Mexique, suite Ă  une analyse comparative, il est dĂ©montrĂ© que la vision des gestionnaires ne semble pas diffĂ©rer en termes de CI. Finalement, malgrĂ© la multitude de programmes gouvernementaux Ă  la fois aux niveaux national et local, trĂšs peu de PME semblent en rĂ©colter les bĂ©nĂ©fices. Le troisiĂšme article tient compte de la thĂ©orie basĂ©e sur les ressources et la thĂ©orie des capacitĂ©s dynamiques afin d’examiner le CI dans les PME mexicaines ainsi que leur relation avec l’avantage compĂ©titif. Une typologie est proposĂ©e et les PME examinĂ©es y sont catĂ©gorisĂ©es en consĂ©quence. Les rĂ©sultats suggĂšrent que les PME avec des capacitĂ©s dynamiques ont instituĂ© des processus Ă  l’interne afin de rĂ©pondre plus rapidement au changement, leur permettant ainsi de gĂ©rer les opportunitĂ©s et les menaces. De plus, elles prennent plus de risques que les PME moins dynamiques lorsqu’il s’agit de saisir des opportunitĂ©s et de les transformer en avantages compĂ©titifs. De tels processus sont intrinsĂšques aux PME dites dynamiques parce qu’ils deviennent partie de la culture organisationnelle.The objective of this thesis is to measure intellectual capital (IC) and its impact on the competitive advantage of small and medium enterprises (SMEs) in Mexico. The main research question is: How should intellectual capital be measured and what is its impact on the competitive advantage of SMEs in Mexico? To answer the research question, the first essay offers a methodological perspective of IC. In this review, the limitations of quantitative methods used in the study of IC are noted. Subsequently, the use of structural equation modeling is discussed and promoted. In the second essay, a measurement model adapted to the realities of Mexican SMEs is proposed. The results suggest that human capital and organizational capital are consistent with previous studies of IC in SMEs. As for external capital, it presents some characteristics unique to the Mexican context. Moreover, despite the socio-economic disparities across regions in Mexico, a comparative analysis shows that the vision of managers does not seem to differ in terms of IC. Finally, despite the multitude of governmental programs at both national and local levels, very few SMEs seem to be reaping their benefits. The third essay takes into account the resource-based and the dynamic-capabilities views to examine IC in Mexican SMEs and its relation to competitive advantage. A typology is proposed and the examined SMEs are categorized accordingly. The results suggest that SMEs with dynamic capabilities have instituted processes within their organizations to respond more rapidly to change, allowing them to manage opportunities and threats. Moreover, they are willing to take more risks than their counterparts, who are characterized by less dynamism in seizing opportunities and transforming them into competitive advantages. Such processes are intrinsic to SMEs because they become part of the culture of organizations

    Unconventional aspects of electronic transport in delafossite oxides

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    The electronic transport properties of the delafossite oxides ABO2_2 are usually understood in terms of two well separated entities, namely, the triangular A+^+ and (BO2_2)−^- layers. Here we review several cases among this extensive family of materials where the transport depends on the interlayer coupling and displays unconventional properties. We review the doped thermoelectrics based on CuRhO2_2 and CuCrO2_2, which show a high-temperature recovery of Fermi-liquid transport exponents, as well as the highly anisotropic metals PdCoO2_2, PtCoO2_2 and PdCrO2_2 where the sheer simplicity of the Fermi surface leads to unconventional transport. We present some of the theoretical tools that have been used to investigate these transport properties and review what can and cannot be learned from the extensive set of electronic structure calculations that have been performed.Comment: 35 pages, 19 figure

    Erectile dysfunction following pelvic fracture

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    A research report submitted to the Faculty of Health Sciences at the University of the Witwatersrand in partial fulfillment of the requirements for the qualifications of MMed (Urology) 2017Background: Erectile dysfunction is one of the most important sequelae of pelvic fractures and may be transient or permanent. It can range from weak erections to severe sexual dysfunctions. Importantly, erectile dysfunction is more prevalent when the pelvic fracture is associated with urethral injury. Methods: This was a retrospective study of patient records, with a prospective questionnaire arm for patients admitted to the hospitals with a pelvic fracture between 01/07/2011 to 30/04/2015. The electronic databases of the Orthopedic Department at Helen Joseph Hospital and the Male Sexual Dysfunction Clinic at Charlotte Maxeke Johannesburg Academic Hospital were accessed for patients' contact details, by using the name and hospital number of each patient. Each patient was contacted telephonically with an open speaker in a presence of a witness/translator. The information sheet was read to the patient before the telephonic consent was obtained. After consent was obtained, patients were asked to verbally complete the International Index of Erectile Function score questionnaire. Results A total of 53 patients participated in the study, of which (43.4%) reported erectile dysfunction. The majority of patients indicated a recovery of erectile function between 2 8 | P a g e to 8 months after the injury. Most were found to still suffer from other forms of sexual impairment like orgasmic dysfunction and sexual satisfaction. However, sexual desire seemed to be preserved. Patients with sexual dysfunction were more likely to have had a urethral injury as well as a more severe fracture. Conclusions In our sample of 53 patients almost half reported sexual dysfunction after a pelvic fracture. Importantly, patients with urethral damage and a severe pelvic fracture should be followed up, as the risk of sexual dysfunction is high in these particular patients.MT201

    Factors Associated with Premenstrual Syndrome and its Different Symptom Domains among University Students in Lebanon

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    Objectives: This study aimed to estimate the prevalence and examine the characteristics of premenstrual syndrome (PMS) among female university students. It also aimed to determine the factors associated with the affective and somatic domains of PMS. Methods: This cross sectional study was conducted among 2115 Lebanese female university students, who completed questionnaires on PMS symptoms and other factors. PMS was defined according to the “American College of Obstetricians and Gynecologists” criteria. Bivariate and multivariable associations between PMS, PMS affective and somatic domains respectively and other covariates were conducted using logistic regression. Results: Almost 63% of participants reported having PMS with 42.5% having severe PMS. The most common affective and somatic symptoms were “angry outbursts” and “abdominal bloating” respectively. Obesity, having unemployed fathers, caffeine consumption (coffee/tea), and pain medication use, and sleeping pill use were significantly associated with PMS. Among these factors, caffeine consumption, and medication use for pain were associated with PMS affective domain while BMI, caffeine consumption, and medication use for pain were related to PMS somatic domain. Conclusion: The proportion of Lebanese females with PMS and affective and somatic symptoms are notably high. These findings highlight the importance of weight management to minimize PMS symptoms.York University Librarie
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