1,249 research outputs found

    Identifying Retweetable Tweets with a Personalized Global Classifier

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    In this paper we present a method to identify tweets that a user may find interesting enough to retweet. The method is based on a global, but personalized classifier, which is trained on data from several users, represented in terms of user-specific features. Thus, the method is trained on a sufficient volume of data, while also being able to make personalized decisions, i.e., the same post received by two different users may lead to different classification decisions. Experimenting with a collection of approx.\ 130K tweets received by 122 journalists, we train a logistic regression classifier, using a wide variety of features: the content of each tweet, its novelty, its text similarity to tweets previously posted or retweeted by the recipient or sender of the tweet, the network influence of the author and sender, and their past interactions. Our system obtains F1 approx. 0.9 using only 10 features and 5K training instances.Comment: This is a long paper version of the extended abstract titled "A Personalized Global Filter To Predict Retweets", of the same authors, which was published in the 25th ACM UMAP conference in Bratislava, Slovakia, in July 201

    Foundation Sign Correction in Stochastic Analysis Procedures

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    There are “ABS, SRSS, CQC, MSRSS…” methods in stochastic analysis of structures, that are based on the mean of the response squares. One of the most accurate stochastic methods is MSRSS, that is defined as equation (1). E[y2]=∑j=1N Rj2 + 2 ∑k=j+1NRjk The maximum modal responses are positive or singles, and therefore direction of the forces act on the foundation are alike. In these cases foundation analysis is not valid and the force sign correction must be used. In this paper, besides considering the stochastic methods shortly, a method for sign correction based on the time history analysis will be presented

    Synthesis and Characterization of 5-Substituted 1H-Tetrazoles in the Presence of Nano-TiCl4.SiO2

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    Nano-TiCl4.SiO2 was found to be an extremely efficient catalyst for the preparation of 5-substituted 1H-tetrazole derivatives. Nano-TiCl4.SiO2 is a solid Lewis-acid was synthesized by the reaction of nano-SiO2 and TiCl4. The structure characterization of this acid was achieved with X-ray diffraction, thermogravimetric analysis and electron microscopy. The synthesis of the catalyst is simple and environmentally benign with a good yield. Furthermore, the catalyst is conveniently recoverable and was reused for at least three times. The antimicrobial activities of the synthetic compounds were also determined by both micro dilution methods as recommended by the Clinical Laboratory Standard Institute, but unfortunately did not exhibit antibacterial activities at the highest concentration (256 μL mL–1). Further studies are still needed to investigate the potential biological activities of these compounds against other diseases.KEYWORDS Nano-TiCl4.SiO2, heterogeneous catalyst, 5-substituted 1H-tetrazoles, antibacterial.PDF and Supp files attache

    A brief review on vessel extraction and tracking methods

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    Extracting an accurate skeletal representation of coronary arteries is an important step for subsequent analysis of angiography images such as image registration and 3D reconstruction of the arterial tree. This step is usually performed by enhancing vessel-like objects in the image, in order to differentiate between blood vessels and background, followed by applying the thinning algorithm to obtain the final output. Another approach is direct extraction of centerline points using exploratory tracing algorithm preceded by a seed point detection schema to provide a set of reliable starting points for the tracing algorithm. A large number of methods fall in these two approaches and this paper aims to contrast them through a brief review of their innate characteristics, associated limitations and current challenges and issues

    Making sense of business analytics : the case of two start-ups

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    Business analytics have enabled businesses to leverage unstructured and dispersed data in order to improve their operations and position themselves better within a highly turbulent environment. While much discussion has been focused on how businesses can move from data to insights to decision making, much less is known around how businesses actually interpret the insights provided by business analytics tools. This extended abstract proposes the use of sense-making as the theoretical lens for interpreting these insights, combined with contextual information. We will be using two case studies to further explore the applicability of our proposition

    Mental health in high-tech system

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    Stress and mental health at the place of work have received great attention by researchers. In spite of technology improvement in high-tech systems, the operators face new problems, which can affect mental health. There is hardly any published research about stress or mental health in such workplaces in developing countries. This paper presents the application of the self-rating scale General Health Questionnaire (GHQ-28) to study mental health of 160 controllers working in a part of Air Traffic Control (ATC) as a high tech system in Iran. Logistic regression analysis showed that demographic variables did not exhibit a statistically significant effect on scores of the test. In order to compare mental health of these operators with general population, an exposure / non-exposure study was designed. Three age groups (less than 29 years, 30 through 39 y, and more than 40 y) were compared in exposed and non-exposed groups. The results of Fisher’s exact test showed that mental distress symptoms were significantly higher in the exposed group. There were significant job effects on somatization, anxiety and depression as well as on the total score of GHQ-28 for the two first age groups (P<.05). No significant effects of the job were found on social dysfunction symptoms in any age groups. The risk ratio of expressing depression and anxiety symptoms were more than three times greater in these operators than general population

    Classification of organizational failure root causes producing human error

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    The formal study of human error is relatively recent, especially in medical domain, and is tied closely to a several other relatively new fields. Organizational root cause of human error is less considered. Despite growing social, industrial and scientific interest in the organizational causes of incidents, the concept of organizational failure and related tools are still less considered in many developing countries e.g. Iran. Also, there is few incident record-keeping in medical domain on human error. Therefore, this study draws on case study research to investigate the applicability of a European taxonomy of organizational failure in Iran, in aviation domain with a fair incident record-keeping. This case study resulted in 10 incident in-depth descriptions, which occurred during one year in a part of civil aviation due to operator error. Within each case study, an explanation building method is used to develop a tool for classifying organizational root causes. Results include 100 root causes. The distribution of organizational root causes over the main categories of the former taxonomy shows a need to add a new sub-category to improve its applicability in Iran. The new sub-category is related to culture

    Clinical presentation of coronary arteriovenous fistula according to age and anatomic orientation

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    Background: Coronary arteriovenous fistulas (CAVFs) are direct connections from one or more coronary arteries to cardiac chambers or a large vessel. They are mostly of congenital origin. The aim of this study was to describe clinical presentation and also delineate the course and management of CAVF. Methods: Clinical data, chest x-rays, echocardiographic and angiographic evaluation of 40 patients with congenital CAVF during 1990 to 2008 were reviewed retrospectively. Results: Seventeen patients were �20 years old (42.5) were mostly asymptomatic, and twenty tree cases were older than 20 years old (57.5), mostly symptomatic (P < 0.05). Twenty one (52.5) patients had pure CAVF and nineteen (47.5) patients with associated intarcardiac congenital heart disease (15) or acquired valvular and coronary arteries diseases (32.5). CAVFs mostly originated from left anterior descending artery (LAD) (42.5) and mostly drained into the main pulmonary artery (MPA) (35 ). Twenty-four patients underwent CAVF surgical ligation. From twenty-one patients with pure CAVF, eight (38) patients were complicated by congestive heart failure and aneurism formation of fistula. Conclusion: Unlike some previous reports, in our study, the most prevalent origin site for CAVFs was the left anterior descending (LAD). Most patients with CAVFs especially those who went first diagnosed before 20 years old were asymptomatic. On the other hand, as the continuous murmur is not always detected in children or infants, consequently, cases of spontaneous closure may remain undetected. All symptomatic and asymptomatic patients with moderate to severe shunting should be operated on and minimal morbidity and good surgical results could be expected
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