232 research outputs found

    Toward quantifying metrics for rail-system resilience: Identification and analysis of performance weak-resilience-signals

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    This paper aims to enhance tangibility of the resilience engineering concept by facilitating understanding and operationalization of weak-resilience-signals (WRS) in the rail sector. Within complex socio-technical systems, accidents can be seen as unwanted outcomes emerging from uncontrolled sources of entropy (functional resonance). Various theoretical models exist to determine the variability of system interactions, the resilience state, and the organization’s intrinsic abilities to reorganize and manage their functioning and adaptive capacity to cope with unexpected and unforeseen disruptions. However, operationalizing and measuring concrete and reliable manifestations of resilience and assessing their impact at a system level, has proven to be a challenge. A multi-method, ethnographic observation and resilience questionnaire, was used to determine resilience baseline conditions at an operational rail traffic control post. This paper describes the development, implementation and initial validation of WRSs identified and modelled around a ‘performance system boundary’. In addition, a WRS analysis function is introduced to interpret underlying factors of the performance WRSs and serves as a method to reveal potential sources of future resonance that could comprise system resilience. Results indicate that performance WRSs can successfully be implemented to accentuate relative deviations from resilience baseline conditions. A WRS analysis function can help to interpret these divergences, and could be used to reveal (creeping) change processes and unnoticed initiating events that facilitate emergence that degrades rail-system resilience. Establishing relevant change signals in advance can contribute to anticipation and awareness, enhance organizational learning and stimulate resilient courses of action and adaptive behavior that ensures rail operation reliability

    A screening method for binding synthetic metallo-complexes to haem proteins

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    The introduction of a second coordination sphere, in the form of a protein scaffold, to synthetic catalysts can be beneficial for their reactivity and substrate selectivity. Here we present semi-native polyacrylamide gel elec-trophoresis (semi-native PAGE) as a rapid screening method for studying metal complex-protein interactions. Such a screening is generally performed using electron spray ionization mass spectrometry (ESI-MS) and/or UV-Vis spectroscopy. Semi-native PAGE analysis has the advantage that it does not rely on spectral changes of the metal complex upon protein interaction and can be applied for high-throughput screening and optimization of complex binding. In semi-native PAGE non-denatured protein samples are loaded on a gel containing sodium dodecyl sulphate (SDS), leading to separation based on differences in structural stability. Semi-native PAGE gel runs of catalyst-protein mixtures were compared to gel runs obtained with native and denaturing PAGE. ESI-MS was additionally realised to confirm protein-complex binding. The general applicability of semi-native PAGE was investigated by screening the binding of various cobalt-and ruthenium-based compounds to three types of haem proteins.Metals in Catalysis, Biomimetics & Inorganic MaterialsSolid state NMR/Biophysical Organic Chemistr

    Household survey evidence on domestic workers in Ethiopia

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    Whilst much scholarly attention of this nascent field of domestic service work focuses on protecting the rights and security of foreign/migrant domestic workers, the nature of domestic service work undertaken within national borders has escaped the attention of both researchers and public policy makers. Outlining the findings from a large household survey data in Ethiopia collected from seven major urban areas covering the period from 1994 to 2004, this paper departs from the usual focus on rights-based perspective and foreign migrant domestic service workers. Instead, the paper attempts to contribute to our understanding of the profile of domestic service providers, the significant drivers of participation in the provision of domestic services and the welfare of unpaid and paid domestic service workers in Ethiopia. In doing so, the paper contributes to the development of a greater evidence base, relevant for both researchers and public policy practitioners alike

    Management system for optimizing public transport networks: GPS record

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    As cities continue to grow in size and population, the design of public transport networks becomes complicated, given the wide diversity in the origins and destinations of users [1], as well as the saturation of vehicle infrastructure in large cities despite their attempts to adapt it according to population distribution. This indicates that, in order to reduce users’ travel time, it is necessary to implement alternative road solutions to the use of cars, increasing investment in public transportation [2, 3] by conducting a comprehensive analysis of the state of transportation. This situation has made appear the solutions and development oriented to transportation based on Internet of Things (IoT) which allows, in a first stage, monitoring of public transport systems, in order to optimize the deployment of transport units and thus reduce the time of transfer of users through the cities [4]. These solution proposals are focused on information collected from user resources (data collected through smart phones) to create a common database [5]. The present study proposes the development of an intelligent monitoring and management system for public transportation networks using a hybrid communication architecture based on wireless node networks using IPv6 and cellular networks (LTE, LTE-M)
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