| 171. |
- Sheline, Jonathan, et al.
(författare)
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Trace Element Similarity Groups in North Florida Spanish Moss
- 1976
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Ingår i: Journal of Geophysical Research. - 2156-2202. ; 81:6, s. 1047-1050
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Tidskriftsartikel (refereegranskat)abstract
- The elemental composition of 10 samples of Spanish moss Tillandsia usneoides L. collected mainly in forested areas near Tallahassee, Florida, has been compared to the composition of the ambient aerosol particle background in the forest measured as a function of particle size. For forest samples, moss composition is similar to the composition of aerosol particles greater than about 0.5-μm diameter for the elements S, Cl, Ti, V, Fe, Ni, Zn, Br, Pb, and possibly Cu. Elements relatively enriched in the moss fall into two groups, K, Rb, Zr and Ca, Sr, Mn, based on detailed association patterns. No evidence is found for an enrichment, relative to the ambient aerosol, of pollution-derived elements Pb, Br, V, and Ni, although those elements are found at higher concentrations in moss samples from locations nearer roadways or oil-fired power plants. The moss appears to have potential value as an indicator of time average aerosol composition for particles of ≥0.5 μm, except for the enriched elements, which may have longer biological retention times.
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| 172. |
- Stewart, Simon, et al.
(författare)
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Establishment of the Global International Fatigue Risk Management Forum
- 2011
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Ingår i: Aviation Psychology and Applied Human Factors. - : Hogrefe Publishing Group. - 2192-0923 .- 2192-0931. ; 1:2, s. 103-109
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Tidskriftsartikel (refereegranskat)abstract
- For many years, fatigue-related risk has been recognized as a significant issue for aircraft operators. The International Civil Aviation Organization (ICAO) states that a basic building block underlying the process of managing safety is “sharing safety lessons learned and best practices through the active exchange of safety information.” An example of this organized active exchange is the global fatigue Risk Management System (FRMS) Forum which was launched in 2009 and includes 65 organizations (2011) (regulators, airline operators, and academic institutions). The Forum is apolitical and facilitates better communication between these bodies. New information from the ICAO and European Aviation Safety Agency (EASA) cites the fact that operators can no longer interpret binary compliance with prescriptive flight time limitations as ensuring “legality” or safety. This paper describes how the FRMS Forum can help.
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| 173. |
- Stewart, Simon, et al.
(författare)
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Integrating Fatigue Risk Management into an Airline's Safety Management System
- 2012
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Ingår i: Proceedings of the 11th International Probabilistic Safety Assessment and Management Conference and the Annual European Safety and Reliability Conference 2012 (PSAM11 and ESREL 2012). ; , s. 5102-5111
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Konferensbidrag (refereegranskat)abstract
- The evolution of a system for the management of fatigue-related risks in airline and maintenance operations is at present a contentious issue. The aspirations for the integration of fatigue risk management processes into existing Safety Management System (SMS) guidelines need to be placed in the realities of the present economic and commercial environment – they therefore need to exhibit relevance and demonstrate cost effectiveness if they are to survive the commercial scrutiny of operators worldwide. Some operators (e.g. easyJet, Air New Zealand, DHL) have already faced the task of making FRMS (Fatigue Risk Management System) relevant to the operation. A recognized and accredited FRMS conversely allows an operator an exemption from the rigid FTL (Flight Time Limitations) rule sets and the flexibility to introduce safe and commercially beneficial rostering solutions. The key to application of an FRMS is defining the relationship between prescriptive FTL and FRMS for an operator that shows benefits over adherence in whole or part to prescriptive FTL. The principle that needs to be debated should be that the rigidity and scope of an operator’s prescriptive FTL requirements are proportionate to the credibility of their FRMS. This paper describes the development and implementation of a Fatigue Risk Management System (FRMS) in a major airline in Europe with a focus on management of fatigue-related risks. The FRMS example focuses on the principles of SMS by employing both Risk Management System (RMS) and Safety Assurance (SA) processes to support evidence-based crew scheduling practices, allowing the identification of structural factors related to consistency and standardisation and performance. This work has been realised as a part of an EU integrated project HILAS (Human Integration into the Lifecycle of Aviation Systems). In the development of the FRMS, the HILAS SMS working group adhered to the principles of Organisational Learning and Resilient Safety Culture.
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| 174. |
- Ternov, Sven, et al.
(författare)
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A method, DEB analysis, for proactive risk analysis applied to air traffic control
- 2004
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Ingår i: Safety Science. - : Elsevier BV. - 0925-7535. ; 42:7, s. 657-673
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Complex production systems as, for instance, those used in health care, in off shore industry, in nuclear power industry or in aviation suffer now and then from severe system breakdowns. Lessons learnt from these often lead to changes in the "system". A more rational approach would be to identify these "system weaknesses" before accidents happen. A new proactive method, DEB analysis, for identifying hazards in a complex system was applied to an air traffic control unit in Malmoe, Sweden. The system weaknesses (i.e. latent system failures and insufficient safety barriers), which could cause these hazards, were identified. The effectiveness of the method was assessed by comparing these "prospective" identified system weaknesses with "retrospective" identified system weaknesses in a consecutive series of loss of separation cases (n = 15), investigated by the central aviation administration. Main findings: The system weaknesses in 14 out of the 15 cases were found with the proactive method. One sub-task was missed. Discussion: The method is an effective tool in disclosing system weaknesses that can give rise to hazards. The method should be modified with increased engagement of operators. It might be applied to other complex systems as well.
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| 175. |
- Ternov, Sven, et al.
(författare)
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Operator-centred local error management in air traffic control
- 2004
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Ingår i: Safety Science. - : Elsevier BV. - 0925-7535. ; 42:10, s. 907-920
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: A large number of air traffic control occurrences take place without resulting in loss of separation between aircraft. Unfortunately such occurrences are seldom reported and therefore not used for disclosing system weaknesses, Such as inappropriate methods and procedures. The ATCC (Air Traffic Control Centre) Malmoe made a trial with local reporting of "learning occurrences". The trial was ATCO-(Air Traffic Controller) centred. The study objectives were to evaluate if ATCOs would start to report after a defined training and marketing effort, if they could identify system weaknesses, if concrete actions for safety improvement would be taken as a result of the trial and to what extent expert support was necessary. Method and material: The trial period was eight months. The ATCO report would be made on a simple form, available on site. These reports would then be analysed in groups and the marketing and feedback efforts would be co-ordinated by the local flight safety group. Results: 43 reports were filed and analysed during the trial period. The initial motivational training and marketing was considered adequate. During the group discussions, the ATCOs identified system weaknesses within 40 of the reports. The resulting safety improvement actions included: the ATCC unit becoming more active in contacting the pilots and airline companies, the renaming of some waypoints (due to name similarities), the implementation of safer procedures when relieving ATCOs, the training of ATCOs in cockpit flight management systems, and the initiation of a research project primarily concerned with ATCO mental overload. Expert support was required in the beginning to help ATCOs focus on the system rather than on the individual.
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| 176. |
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| 177. |
- Ternov, Sven, et al.
(författare)
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System weaknesses as contributing causes of accidents in health care
- 2005
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Ingår i: International Journal for Quality in Health Care. - : Oxford University Press (OUP). - 1464-3677 .- 1353-4505. ; 17:1, s. 5-13
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Tidskriftsartikel (refereegranskat)abstract
- Objectives. Accidents in health care, resulting in injury or death to the patient, are a matter of considerable concern. The aim of this study is to examine whether system weaknesses can contribute to these accidents, and if so, how. Design. Eight consecutive accidents reported to the Health Authority in Sweden were analysed using MTO (Man-Technique-Organization) analysis. Setting. Emergency care hospitals in Sweden. Results. All cases that involved the system supported the assumption that system weaknesses are a contributing factor to accidents. In this study two types of latent failure could be identified: process control latent failures and interactional latent failures. The time span from activation of process control latent failures to operator error was very short, and the study demonstrates the simple relationship between situational factors and operator errors. Interactional latent failures exert system influence in a more indistinct manner. Latent failures, as seen in this study, act not only by creating opportunities for operator errors but also by hindering error detection in the time window available. Safety barriers, which might have prevented the accidents, could be proposed in seven out of eight cases. Conclusion. System weaknesses seem to play an important role in accident evolution. Consequently, certain measures can be suggested in order to improve patient safety: (i) sufficient resources should be allocated for research and development at both medical schools and hospitals in order to establish competence and procedures for systematic analyses of processes; and (ii) authorities handling accident cases should have adequate competence in system analysis.
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| 178. |
- Van Grieken, René E., et al.
(författare)
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Geophysical Applicability of Aerosol Size Distribution Measurements Using Cascade Impactors and Proton Induced X-Ray Emission
- 1976
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 0004-6981. ; 10:8, s. 571-576
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Tidskriftsartikel (refereegranskat)abstract
- Proton Induced X-ray Emission, (PIXE), is capable of high precision analysis for trace element components of aerosol particle size fractions sampled by cascade impactor. A statistical evaluation of data quality has been carried out in order to distinguish between analytical uncertainties in the PIXE procedure, errors caused by cascade impactor performance and by other factors in the sampling procedure, and geophysical causes of differences in composition and particle size distributions of the elements in aerosols. Replicate analyses and simultaneous samplings taken in north Florida and St. Louis have been used for the data evaluation. In addition to the analytical error the sampling procedure contributes an error of ~ 10% to be added quadratically. The resulting precision is sufficient to evaluate the data in geophysical terms. This is illustrated by means of sample sets taken simultaneously in an urban, forest and coastal environment of the same region.
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| 179. |
- Weikert, Clemens, et al.
(författare)
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Air Traffic Controllers and Incidents: An Explorative Interview Study
- 2001
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Ingår i: Miedzynarodowa konferencja bezpieczenstwa i niezawodnosci : KONBiN 2001 (Safety and Reliability International Conference). ; , s. 139-142
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Konferensbidrag (refereegranskat)abstract
- An explorative interview study was performed with 21 air traffic controllers having experienced air traffic control incidents (loss of separation between aircraft). The results of the interview study identified the following main factors contributing to the occurrence of incidents: 1) memory malfunctions; 2) concentration problems; 3) distractions; 4) inadequate expectations; 5) deficient phraseology. The results agree with the results from an analysis of incident investigation reports.
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| 180. |
- Weikert, Clemens, et al.
(författare)
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Computerization of the Control Function in a Process Industry: A Case Study
- 1993
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Ingår i: Interacting with Computers: Preparing for he Nineties. ; , s. 251-257
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Konferensbidrag (refereegranskat)abstract
- Computerization of control room functions changes the work for the operators to a great extent. Their mental picture of the process, their possibilities to control the process for productivity and quality, the work content, the physical and the social working environment are examples of conditions which are changed one way or another. In order to be able to control the computerization process in an optimal way it is important to perform and to learn from case studies. In a Swedish paper pulp industry, where computerized control and information systems have been implemented and where operators have been involved in the computerization process, we have pursued an interview investigation. Twenty-eight operators and ten employees in other key positions have been asked e.g. about the control room design, the control system, the information system the effects of computerization on the work load and on the physical, mental and social working environment. Results from the interviews are presented and discussed. The control room design and the human-computer interfaces have been evaluated against guidelines and some of the results are discussed.
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