24,734 research outputs found

    A review of key planning and scheduling in the rail industry in Europe and UK

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    Planning and scheduling activities within the rail industry have benefited from developments in computer-based simulation and modelling techniques over the last 25 years. Increasingly, the use of computational intelligence in such tasks is featuring more heavily in research publications. This paper examines a number of common rail-based planning and scheduling activities and how they benefit from five broad technology approaches. Summary tables of papers are provided relating to rail planning and scheduling activities and to the use of expert and decision systems in the rail industry.EPSR

    The Firm Size Distribution and Inter-Industry Diversification

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    We show that the stylized facts of the Firm Size Distribution (FSD) by age cohorts, as shown in Cabral and Mata (2003), bind within 4-digit manufacturing industries in the UK and Belgium. As in Klepper and Thompson (2006) and Sutton (1998), we explore whether time to build a portfolio of products is a mechanism that relates age to firm size. While inter industry diversification, to some extent, accounts for the role of age, we find that the presence of economies of scope has a separate impact on firm size when controlling for age, amongst other factors. Using the techniques in Cabral and Mata's we show that the FSD by degrees of product diversification shifts to the right, but more so in older age groups. This shows a role for inter-industry diversification over and above an age effect.

    The developing field of integrated vehicle health management

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    The goals that are being set for aviation growth in the near future, combined with the growth in service provision, are unattainable without active health management of airplanes. Numbers associated with door to door travel time and accident rates, coupled with availability demands to provide cost-effective transport, simply do not allow time for unscheduled maintenance. We are therefore going to experience a step jump in the take up of Integrated Vehicle Health Management (IVHM) on these platforms in order to give accurate warning of sub-system and component degradation, allowing for maintenance to be carried out in a timely, scheduled, manner. This paper describes the development of IVHM, covering emerging services, standards, technology and IVHM as used in various industry sectors. This will lead to the commercial picture of today with the top level goals that are being set, providing the business push for technology and its adoption. Examples of research being conducted in the field will be shown, to support the claim that real progress is being made, with implementation of this technology on the horizon.http://www.aerojournalindia.com/journal.htm

    The space physics environment data analysis system (SPEDAS)

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    With the advent of the Heliophysics/Geospace System Observatory (H/GSO), a complement of multi-spacecraft missions and ground-based observatories to study the space environment, data retrieval, analysis, and visualization of space physics data can be daunting. The Space Physics Environment Data Analysis System (SPEDAS), a grass-roots software development platform (www.spedas.org), is now officially supported by NASA Heliophysics as part of its data environment infrastructure. It serves more than a dozen space missions and ground observatories and can integrate the full complement of past and upcoming space physics missions with minimal resources, following clear, simple, and well-proven guidelines. Free, modular and configurable to the needs of individual missions, it works in both command-line (ideal for experienced users) and Graphical User Interface (GUI) mode (reducing the learning curve for first-time users). Both options have “crib-sheets,” user-command sequences in ASCII format that can facilitate record-and-repeat actions, especially for complex operations and plotting. Crib-sheets enhance scientific interactions, as users can move rapidly and accurately from exchanges of technical information on data processing to efficient discussions regarding data interpretation and science. SPEDAS can readily query and ingest all International Solar Terrestrial Physics (ISTP)-compatible products from the Space Physics Data Facility (SPDF), enabling access to a vast collection of historic and current mission data. The planned incorporation of Heliophysics Application Programmer’s Interface (HAPI) standards will facilitate data ingestion from distributed datasets that adhere to these standards. Although SPEDAS is currently Interactive Data Language (IDL)-based (and interfaces to Java-based tools such as Autoplot), efforts are under-way to expand it further to work with python (first as an interface tool and potentially even receiving an under-the-hood replacement). We review the SPEDAS development history, goals, and current implementation. We explain its “modes of use” with examples geared for users and outline its technical implementation and requirements with software developers in mind. We also describe SPEDAS personnel and software management, interfaces with other organizations, resources and support structure available to the community, and future development plans.Published versio

    Corporate Governance, Managers’ Independence, Exporting And Performance Of Firms In Transition Economies

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    Using data on 157 large companies in Poland and Hungary this paper employs a Bayesian structural equation modeling to examine interrelationships between corporate governance, managers’ independence from owners in terms of strategic decision-making, exporting and performance. It is found that managers’ independence is positively associated with firms’ financial performance and exporting. In turn, the extent of managers’ independence is negatively associated with ownership concentration, but positively associated with the percentage of foreign directors on the firm’s board. We interpret these results as an indication that (i) concentrated owners tend to constrain managerial autonomy at the cost of the firm’s internationalization and performance, (ii) board participation of foreign stakeholders, on the other hand, enhances the firm’s export orientation and performance by encouraging executives’ decision-making autonomy.corporate governance, strategic independence, exporting, performance
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