1,720,993 research outputs found
Increasing Safety at Level Crossings: Hazards Identification and Risk Assessment to Optimize Preventive Actions Implementation
No full textFrom the continuous improvement of rail safety performances and, specifically, for supporting the identification of the most effective measures to prevent accidents, the focus is on the level crossings, largely representing the most safety critical elements of the railway network. The paper setups an effective methodology for ranking the level crossings in view of optimizing the implementation of actions capable to reduce the risks at intersections between rail and road. The methodology acts as a strategic tool for the maximization of the effectiveness of investments for level-crossing safety improvement. The proposed approach is basing on risk analysis methods, focused on significant variables for typical hazards, customized for the level crossings' operation. The proposed method allows determining an upgradable ranking process, which qualifies and sorts single level crossings, according to typical hazards, addressing affordable times and modes for their mitigation
Effetti delle dimensioni delle navi sulle emissioni delle flotte container e passeggeri // Effects of ships’ dimension on emissions of container and cruise fleets
No full textThe paper approaches freight and passengers fleets, affected by naval gigantism, to investigate its energetic and environmental effects. Among the emerging trends, we encounter the increase of the installed power and, more relevantly, of the transport capacity of the ships. The result is a decrease of the specific power, particularly in the last 20 years. In the same period, an increase of the performances of ships in terms of environmental and energetic sustainability is ongoing. A further acceleration in this direction could come from the introduction of less pollutant fuels and renewable energies. It is a pillar for the development of future sustainable fleets, with relevant emerging investigation needs. In this context, the paper proposes a synthetic approach, combining dimensions and environmental performances of ships, tested on container and cruises fleets in operation in selected worldwide most frequented locations. The results could be useful to check effective policies, basing on emerging technologies and implementation of new rules and regulation
Technical-economical analysis of cold-ironing. Case study of Venice cruise terminal
Full text linkCold-ironing is the practice that enables to power commercial ships by a link to fixed electricity network, in order to reduce pollutant emissions in the port areas caused by marine fuels in auxiliaries engines feeding on board installations during ships stops at quays. The present paper aims to provide an overview of the most important technical and functional features of the concerned ships power systems and to analyze the technical, economic and financial feasibility of this system. In the first part the main technical-constructive elements for the application of Cold-ironing to different types of ship (such as voltage, frequency, power supply and power demand on the quay) are analyzed. The variety of functional situations does not allow to establish general constructive solutions since the cold-ironing system is depending both on the operational mode and the layout of each terminal. In the second part of the paper it has been analyzed the case study of the cruise terminal in Venice (VTP Spa Venice Passenger Terminal) with the aim of verifying the feasibility of a cold-ironing system for power supply of cruise ships on quays. The analysis was based on ships timetable for the year 2012, which includes the arrivals and the departures of 86 different ships with a global volume of 570 movements. Starting from data on dwell times, following the guidelines of the MEET methodology for estimating emission factors [3] it has been estimated pollutant emissions (nitrogen oxide NOx, sulfur oxides SOx, volatile organic compounds VOC, particulates PM, carbon monoxide CO) as a basis to calculate externalities to be considered for the Cost-Benefit Analysis (CBA). Based on a probabilistic analysis of the terminal occupation by ships (disposal of ship stalls on each quays) five operational scenarios were defined. Each scenario has been defined on the basis of an economic evaluation by means of a cost-benefit parametric analysis with the aim of providing the maximum financial results for assigned budgets. From a comparison of the results of the cost-benefit analysis and an estimate of possible investment costs obtained from USA case studies, it is noticed that the scenario providing coverage of both financial and economic investment includes the minimum number of electrified stalls and a ships journeys reorganization. It was also proposed a sensitivity analysis of CBA for the evaluation of indicators variations according to reference conditions variation
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
Mortality by education level at late-adult ages in Turin: a survival analysis using frailty models with period and cohort approaches
No full textObjectives: Neglecting the presence of unobserved heterogeneity in survival analysis models has been showed to potentially lead to underestimating the effect of the covariates included in the analysis. This study aimed to investigate the role of unobserved heterogeneity of frailty on the estimation of mortality differentials from age 50 on by education level. Design: Longitudinal mortality follow-up of the census-based Turin population linked with the city registry office. Setting: Italian North-Western city of Turin, observation window 1971-2007. Population: 391 170 men and 456 216 women followed from age 50. Primary outcome measures: Mortality rate ratios obtained from survival analysis regression. Models were estimated with and without the component of unobserved heterogeneity of frailty and controlling for mortality improvement over time from both cohort and period perspectives. Results: In the majority of cases, the models without frailty estimated a smaller educational gradient than the models with frailty. Conclusions: The results draw the attention of the potential underestimation of the mortality inequalities by socioeconomic levels in survival analysis models when not controlling for unobserved heterogeneity of frailty.</p
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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