1,721,053 research outputs found
Vibration transmitted by excavators and wheel loaders: assessment of the seat transmissibility
No full textThe occupational exposure to whole-body vibrations represents a primary health risk for the drivers of earth-moving machinery typically used in mining, mine reclamation and construction work. The measurements taken on a considerable number of off-road vehicles showed that the vibration transmitted through the vehicle seat usually exceeds the exposure action value established by law. The article discusses the latest development in an on-going research project which was started three years ago and involves a number of mines and mining remediation sites located in Sardinia. The results of the most recent measurements taken on a number of excavators and wheel loaders have been analysed in order to assess the dynamic response of the seat-person system; for each case under investigation the transmissibility of the seat was established by comparing the vibration signals provided by two accelerometers mounted on the seat pan and at the base of the seat
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
Assessment of Occupational Exposure to Whole-Body Vibration for Drivers of Earth-Moving Vehicles
No full textAccording to the data provided by the most recent European Survey on Working Conditions, roughly 25% of the European working population is exposed to mechanical vibrations for no less than 1⁄4 of the work shift duration, while around 10% are exposed for the entire work shift. The occupational exposure to Whole Body Vibration (WBV), in particular, represents a major health risk in mining, quarrying and civil excavation activities. In accordance with European directive 2002/44/EC, the latest version of the Italian law on physical risks has recently confirmed the possibility of using relevant literature data on vibration magnitude in order to evaluate personal occupational exposure (vibration database or data provided by the manufacture). Still the alternative option, based on field measurements, represents the most appropriated method of risk assessment, as it accounts for the actual operating condition at the workplace: actual operator and vehicle under investigation and specific working cycle. The article discusses the vibration measurements taken on a number of heavy machinery (excavators, loaders, trucks, dumpers, etc.) employed for talc extraction in a mine located in Sardinia and the resulting personal exposure for the drivers. The assessment was carried out in accordance with the specifications of ISO 2631-1 and EN 14253
Occupational exposure to noise and vibration in mine reclamation
No full textThe occupational exposure to noise and vibration transmitted by earth moving machinery and hand-held equipment represents a major occupational health issue in mining and mine reclamation activities. Previous research proved that noise-induced hearing loss (NIHL) can be amplified by the exposure to hand-transmitted vibration; in fact it has been suggested that workers affected by vibration white finger syndrome (VWF) can be at higher risk of hearing loss, as the vibration might cause the vasoconstriction of the blood vessels in the inner ear. The article discusses the result of the exposure assessment for the workers employed in a number of abandoned mines located in southern Sardinia, where extensive mine remediation and environmental rehabilitation work is currently in progress. The personal exposure to noise, whole-body vibration and hand-arm vibration has been evaluated on the basis of the measurements taken on-site, considering the remediation tasks typically performed by the workers
Evaluating the Prediction Bias Induced by Label Imbalance in Multi-label Classification
Full text linkPrediction bias is a well-known problem in classification algorithms, which tend to be skewed towards more represented classes. This phenomenon is even more remarkable in multi-label scenarios, where the number of underrepresented classes is usually larger. In light of this, we hereby present the Prediction Bias Coefficient (PBC), a novel measure that aims to assess the bias induced by label imbalance in multi-label classification. The approach leverages Spearman's rank correlation coefficient between the label frequencies and the F-scores obtained for each label individually. After describing the theoretical properties of the proposed indicator, we illustrate its behaviour on a classification task performed with state-of-the-art methods on two real-world datasets, and we compare it experimentally with other metrics described in the literature
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
A Portable Wireless-Based Architecture for Solving Minimum Digital Divide Problems
Full text linkIn today's society digital services have become the key to the success of anyone. Hence, for being competitive it is important that these services are available, employ the latest technology and are low cost. Unfortunately, it often happens that these good intentions do not correspond to reality. In this paper an information system is proposed, targeted at those small realities affected by the digital divide and at those companies that employ out of date, high cost technologies, that provides data and voice services in a unified manner using heterogeneous devices. The system utilizes innovative technologies, in particular wireless technology, to deliver low cost solutions. The distinctive feature is that it does not depend on the network hardware infrastructure and the underlying platform. Furthermore, it deals with the configuration, accounting, security, management, and monitoring aspects while maintaining its flexibility and simplicity of use both for the administrator and end user
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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