1,720,979 research outputs found
Load cell torques and force data collection during tele-operated robotic gas tungsten arc welding in presence of collisions
No full textTorque and force signals data were acquired from a load-cell sensor during a robotic welding process, in presence of collisions between the tool and the workpiece edges outlined in part in "Haptic-based touch detection for collaborative robots in welding applications" [1]. The dataset is composed from 15 tests captured during a tele-operated welding robot performing a 1G ASME/AWS (i.e., PA ISO) welding process. The raw data files have been provided. These data can be used to correlate torque signal features with collision events, to improve algorithms of collision detection/avoidance and to develop reliable real-time haptic feedback to the welder. This dataset can also be used to study the torque signal variation in different welding positions (e.g., 2G, 3G, 2F, etc.). Dataset is provided as raw data and in MATLAB files
Atorvastatin increases ecNOS levels in human platelets of hyperlipidemic subjects
No full textBACKGROUND: The purpose of this study was to probe the pleiotrophic effects of Atorvastatin on intraplatelet-nitric oxide metabolism.
METHODS AND RESULTS: Hyperlipidemic subjects (n = 19) were treated for 1 month (following a 3-week washout) with either Atorvastatin or placebo in a double-blinded randomized (n = 2, crossover), placebo-controlled study. Changes in the levels of intraplatelet nitric oxide synthase, nitrotyrosine were correlated with cholesterol, LDL-C, HDL-C and triglyceride levels. These studies indicate that with atrovastatin ecNOS levels increased on average by approximately approximately 1.7-fold (paired t-test p = 0.009). Interestingly, levels of nitrotyrosylated platelet proteins, an indication of peroxynitrite damage, decreased as ecNOS levels increased in presence of the drug (paired t-test p = 0.33). Atorvastatin, at 10 mg per day, lowered cholesterol and LDL-C levels in all patients with the average lowering of approximately 21% and approximately 17% respectively. The effect on HDL was not significant whilst triglyceride levels were lowered by an average of approximately 18%.
CONCLUSIONS: This study adds to the volume of evidence that statins have beneficial effects other than lipid lowering. Here, Atorvastatin is shown to significantly elevate intraplatelet ecNOS levels in hyperlipidemic subjects without affecting iNOS expression. The net result of this would be the elevation of NO production which would promote platelet deaggregation and vasodilation
State-Dependent Riccati Equation Control for Spacecraft Formation flying in the Circular Restricted Three-Body Problem
Full text linkThe use of the state-dependent Riccati equation (SDRE) technique for formation flying control in the circular restricted three-body problem is investigated in this paper. First, the relative dynamics of a leader-follower formation is described by computing the difference between the equations of motion associated to the two spacecraft. Then, a pseudo-linear form of the relative motion equations is identified in order to implement the SDRE control technique. The effectiveness of the controller is proved by the high accuracy and the limited control usage achieved during the numerical simulations, set up considering the New Worlds Observer mission scenario
Spacecraft relative motion control using the state-dependent Riccati equation technique
Full text linkIn this paper, an overview of the state-dependent Riccati equation (SDRE) control technique is proposed, with focus on spacecraft relative motion control. The SDRE method offers a systematic and effective approach for designing nonlinear controllers and observers, with appealing properties of stability, optimality, and robustness. Such characteristics have made the method popular since the 1990s, and a wide number of applications can be found in literature. In this work, we focus our attention on its use for the development of guidance systems, aimed at controlling the relative motion between two or more spacecraft. In particular, the method is first used to design a guidance law for formation control around libration point. Then a set of modifications are proposed, aimed at increasing pointwise stability and at reducing computational cost. These are tested and compared on a debris mitigation mission in lower Earth orbit
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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