1,720,959 research outputs found
Human factor analysis embedded in risk assessment of industrial machines: Effects on the safety integrity level
No full textThe study proposed in this paper consists of devising a method to account qualitatively and quantitatively for the human factor in verifying the Integrity Level of Safety system (SIL) assigned to the machinery. It is called "operational SIL", which may differ from the design SIL, due to the impact of human and organizational factors (H&OF) in the operational phase. There are two crucial aspects related to modelling man-machine interaction in Quantitative Risk Analysis (QRA) context: 1. the need to insert human interaction in the logical model of QRAs techniques; 2. the quantification of effect of human factors. During the study an Operability Analysis, which is usually known with the acronym HAZOP (Hazard and Operability studies) was initially used to support the assessment, but with some added features that enable one to accommodate systematically H&OF into the process called Integrated Recursive Operability Analysis framework (IROA). This first attempt to apply IROA methodology showed that this type of analysis highlights the position where in depth human factor analysis must be carried out. Once the point is identified in which the human erroneous action may occur it will be necessary to include the study of human factors and the assessment human error probability (HEP). Our efforts are aimed at defining an improved methodological framework encompassing the integration of H&OF into safety analysis by means of quantitative risk assessment schemes. In order to do that the adopted tool is the Integrated Dynamic Decision Analysis (IDDA). This tool allows modelling the logic of a complex system; it provides a representation of all the possible alternative states into which the system could evolve, as a real logical and temporal sequence of events. The proposed model is designed precisely with the aim of transferring the IDDA philosophy to the in-depth study of the deviations which may occur during human implementation of operational procedures. IDDA developed on the basis of a Task Analysis (TA) could allow to obtain a detailed quantitative analysis of human factors directly during the same risk assessment. Starting from the analysis of a technological system through IDDA it is possible to integrate in the logical model a task analysis describing where and why the operator can cheat or by-pass the safety system thus including in the assessment explicitly the human factors that allow evaluating the operational SI
Human Factor Effects on the Safety Integrity Level Assigned to Safety-Related Electrical Control System in the Operational Phase
No full text
Human Factor Analysis Embedded in Risk Assessment of Industrial Machines: Effects on the Safety Integrity Level
No full textThe study consists in devising a method to account qualitatively and quantitatively for the human factor in verifying the Safety Integrity Level (SIL) assigned to machinery. Two crucial aspects have to be taken into account modelling man-machine interaction in Quantitative Risk Analysis (QRA): 1. The need to include the human interaction in the logical model of QRAs techniques; 2. The quantification of the effect of human factors. The efforts were thus aimed at defining an improved methodological framework encompassing the integration of Human and Organisational Factors (H&OF) into safety analysis by means of quantitative risk assessment schemes. In the end, the Integrated Dynamic Decision Analysis (IDDA) was adopted, integrated to Task Analysis. This tool allows modelling the logic of a complex system; it provides a representation of all the possible alternative states into which the system could evolve as a real logical and temporal sequence of events. The proposed model is designed with the aim of transferring the IDDA philosophy to the in-depth study of the deviations that may occur during human implementation of operational procedures and to analyse their effects on system reliability
Application of standard IEC 62061 to a case study on hydraulic press
No full textThe standard IEC 62061 is a machine sector specification within the framework of IEC 61508. It is intended to facilitate the specification of the performance of safety-related electrical control systems in relation to the significant hazards of machines.
Compliance with this standard provides one with means of conformity with the specified essential requirements given in Annex I of the EC Directive 2006/42/EC.
This paper reports a case study on a press where an accident occurred. Through an appropriate risk analysis and reliability data a priority of interventions has been defined to reduce risks in the specific machine under investigation. The main target of the analysis was to test the applicability of most recent generation standards, that are not yet fully acquired by different industries, and to verify their effectiveness.
A risk assessment was performed in order to verify the compliance with the essential requirements of the Machinery Directive 2006/42/EC.
A risk assessment should include a look at each functional part in turn, making sure that every mode of operation and all phases of use are properly considered, including the human-machine interaction in
relation to the identified functions or functional parts. For this reason the Hazard Identification approach (HazID) was chosen to investigate the criticalities of the bending tool. The HazId analysis was used as a
support for the determination of the required Safety Integrity Level (SIL) of the safety-related functions that must be realized by a safety-related system.
Once SIL has been assigned to Safety-Related Electrical Control System (SRECS), it was fundamental to calculate the SIL associated to that component and to verify if it is equal to the previously
assigned SIL.
This case study has shown that the performance of a safety instrumented system in the operational phase is influenced by many factors; not only by the system design and the related testing and maintenance strategies, but also by the operating conditions in the wider socio-technical system.
For this reason it is important to account for the human factor in assigning integrity levels of safety systems (SIL) to the identified security functions
Human factors issues and the risk of high voltage equipment: Are standards sufficient to ensure safety by design?
No full textHigh voltage equipment is mostly designed according to technically prescriptive standards requirements based on electrical engineering safety principles. However a more risk-based approach to standards and regulation may be advisable to enable designer and user to take an active role in establishing that their installation is inherently safe. The use of Gas Insulated Switchgear (GIS) for instance is enabling the new substation to be housed indoors and condensed into around one quarter of the space. The manufacturers argue that design improvements in GIS make it virtually "maintenance free", comply with all the relevant standards. However some of these improvements have implications for the operators that need to be taken into account. Commissioning, operational checks and inspections and the occasional maintenance interventions are activities during which the technicians need to interface with the equipment, the issues regarding the interfaces provided have been analysed to identify their relevance in the overall risk assessment of the equipment. The paper reports about a study aimed at verifying through a risk analysis the impacts that the issues related to deficit in ergonomic design may present for the overall availability and safety of the plant. Those issues are not tackled in the technical standards and/or designers current practice
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
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