157,390 research outputs found
Taxonomic classification of planning decisions in health care: a review of the state of the art in OR/MS
We provide a structured overview of the typical decisions to be made in resource capacity planning and control in health care, and a review of relevant OR/MS articles for each planning decision. The contribution of this paper is twofold. First, to position the planning decisions, a taxonomy is presented. This taxonomy provides health care managers and OR/MS researchers with a method to identify, break down and classify planning and control decisions. Second, following the taxonomy, for six health care services, we provide an exhaustive specification of planning and control decisions in resource capacity planning and control. For each planning and control decision, we structurally review the key OR/MS articles and the OR/MS methods and techniques that are applied in the literature to support decision making
Aerospace medicine and biology: A continuing bibliography with indexes (supplement 341)
This bibliography lists 133 reports, articles and other documents introduced into the NASA Scientific and Technical Information System during September 1990. Subject coverage includes: aerospace medicine and psychology, life support systems and controlled environments, safety equipment, exobiology and extraterrestrial life, and flight crew behavior and performance
A Winning Hand: A Proposal for an International Regulatory Schema with Respect to the Growing Online Gambling Dilemma in the United States
While a multitude of Internet enterprises folded in the 1990s, online gambling websites not only have held strong, but appear to be ready to increase the stakes. No business relating to the Internet currently generates more revenue than online gambling, and that trend does not look like it will change soon. While many Americans desire to participate in this form of cyber-gambling, the current legality of their ability to do so remains vague. For the most part, an American\u27s ability to gamble currently resides under the purview of state law and a hodgepodge of antiquated federal wire acts. The nature of the Internet, however, mandates that any scheme, regulatory or prohibitory, be constructed in the international arena. For various reasons, there have been efforts by members of Congress to create strong prohibitory legislation specifically targeting Internet gambling. The Author analyzes not only whether a domestic prohibition schema is the best model to implement, but also whether such a model could even be truly effective. The Author further shows that an international regulatory model can provide a legitimate method of control while allowing individual countries to maintain discretion over the form of online gambling they allow to their citizens. At the same time, this international regulatory schema would still provide a valid international enforcement net against offenders. Under this regulatory schema, problem gamblers can be protected while still preserving the opportunity for other patrons to get lucky and hit it big
The agricultural impact of the 2015â2016 floods in Ireland as mapped through Sentinel 1 satellite imagery
peer-reviewedIrish Journal of Agricultural and Food Research | Volume 58: Issue 1
The agricultural impact of the 2015â2016 floods in Ireland as mapped through Sentinel 1 satellite imagery
R. OâHaraemail
, S. Green
and T. McCarthy
DOI: https://doi.org/10.2478/ijafr-2019-0006 | Published online: 11 Oct 2019
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Abstract
The capability of Sentinel 1 C-band (5 cm wavelength) synthetic aperture radio detection and ranging (RADAR) (abbreviated as SAR) for flood mapping is demonstrated, and this approach is used to map the extent of the extensive floods that occurred throughout the Republic of Ireland in the winter of 2015â2016. Thirty-three Sentinel 1 images were used to map the area and duration of floods over a 6-mo period from November 2015 to April 2016. Flood maps for 11 separate dates charted the development and persistence of floods nationally. The maximum flood extent during this period was estimated to be ~24,356 ha. The depth of rainfall influenced the magnitude of flood in the preceding 5 d and over more extended periods to a lesser degree. Reduced photosynthetic activity on farms affected by flooding was observed in Landsat 8 vegetation index difference images compared to the previous spring. The accuracy of the flood map was assessed against reports of flooding from affected farms, as well as other satellite-derived maps from Copernicus Emergency Management Service and Sentinel 2. Monte Carlo simulated elevation data (20 m resolution, 2.5 m root mean square error [RMSE]) were used to estimate the floodâs depth and volume. Although the modelled flood height showed a strong correlation with the measured river heights, differences of several metres were observed. Future mapping strategies are discussed, which include highâtemporal-resolution soil moisture data, as part of an integrated multisensor approach to flood response over a range of spatial scales
Empirical exploration of air traffic and human dynamics in terminal airspaces
Air traffic is widely known as a complex, task-critical techno-social system,
with numerous interactions between airspace, procedures, aircraft and air
traffic controllers. In order to develop and deploy high-level operational
concepts and automation systems scientifically and effectively, it is essential
to conduct an in-depth investigation on the intrinsic traffic-human dynamics
and characteristics, which is not widely seen in the literature. To fill this
gap, we propose a multi-layer network to model and analyze air traffic systems.
A Route-based Airspace Network (RAN) and Flight Trajectory Network (FTN)
encapsulate critical physical and operational characteristics; an Integrated
Flow-Driven Network (IFDN) and Interrelated Conflict-Communication Network
(ICCN) are formulated to represent air traffic flow transmissions and
intervention from air traffic controllers, respectively. Furthermore, a set of
analytical metrics including network variables, complex network attributes,
controllers' cognitive complexity, and chaotic metrics are introduced and
applied in a case study of Guangzhou terminal airspace. Empirical results show
the existence of fundamental diagram and macroscopic fundamental diagram at the
route, sector and terminal levels. Moreover, the dynamics and underlying
mechanisms of "ATCOs-flow" interactions are revealed and interpreted by
adaptive meta-cognition strategies based on network analysis of the ICCN.
Finally, at the system level, chaos is identified in conflict system and human
behavioral system when traffic switch to the semi-stable or congested phase.
This study offers analytical tools for understanding the complex human-flow
interactions at potentially a broad range of air traffic systems, and underpins
future developments and automation of intelligent air traffic management
systems.Comment: 30 pages, 28 figures, currently under revie
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A framework of justification criteria for advanced manufacturing technology implementation in small and medium enterprises
Today in order to stay in businesses and prosper, Small and Medium Enterprises (SMEs) are seeking higher electiveness and competitiveness across the entire cycle of marketing, product design, manufacture, test and sales. SMEs play an increasingly important role in all aspects of competitiveness: both products and production techniques, but also management methods, the organization of the firm and human resources training. One of the ways by which SMEs can achieve a competitive advantage in manufacturing is through the implementation of Advanced Manufacturing Technology (AMT). An increasing number of them have chosen and are choosing various levels of AMT as the solution. Realizing the importance of SMEs, an attempt has been made in this paper to review the application of AMT in SMEs. Also, a framework has been offered for the implementation of AMT in SMEs. Finally, a summary of findings and conclusions are presented
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Investigating the factors affecting information systems evaluation within sustainable environments
Copyright @ 2013 EMCIS.Currently, organizations and stakeholders are more concerned with environmental issues, thus the role of information systems (IS) and information technologies (IT) within organizations towards ecological being sustainability has changed. Environmental or Green initiatives is realized as having credibly to assist in shifting to a sustainable society. Furthermore, the elements within IS/IT evaluation including costs, benefits and risks within organizations associated with IS evaluation and sustainability are taken into account in terms of the challenges concerning green practices (Green IS/IT) leading the organizations to attempt to diminish the impact of their IS/IT operations towards the environments socially and ethically, which indirectly assist them in achieving competitive advantages competitors through adopting and implementing environmental sustainability practices. In addition, government sectors are taking a step closer in order to create awareness and incorporate green into all components of the business functions. Practitioners and scholars are motivating to use the existing frameworks and models to evaluate IS/IT initiatives with sustainability taken into perspectives. Consequently, the purpose of this paper is to critically review the normative literature associated with IS evaluation within sustainable environments and to develop a conceptual framework or model for IS evaluation within sustainable organizations that measures the impact of environmental sustainability factors and highlight a number of research gaps that need to be addressed in future research
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The Influence of geometrical and operational parameters on internal flow characteristics of Internally Mixing Twin-Fluid Y-Jet Atomizers
Internally mixing twin-fluid Y-jet atomizers are widely used in coal fired thermal power plants for start-up, oil-fired thermal power plants and industrial boilers. The flow through internally mixing Y-jet atomizers is numerically modeled using the compressible Navier-Stokes equations; Wall Modeled Large Eddy Simulations (WMLES) is used to resolve the turbulence with Large Eddy Simulations whereas the Prandtl Mixing Length Model is used for modeling the subgrid scale structures, which are affected by geometric and operational parameters. Moreover, the Volume-of-Fluid (VOF) method is used to capture the development and fragmentation of the liquid-gas interface within the Y-jet atomizer. The numerical results are compared with correlations available in open literature for the pressure drop; further results are presented for the multiphase flow regime maps available for vertical pipes. The results show that the mixing point pressure is strongly dependent on the mixing port diameter to airport diameter ratio, specifically for gas to liquid mass flowrate ratio (GLR) in the range 0.1 < GLR < 0.4; the mixing port length moderately affects the mixing point pressure while the angle between mixing and liquid ports is found not to have an appreciable effect. Moreover, it is found that the vertical pipe multiphase flow regime maps in the literature could be applied to the flow through the mixing port of the twin-fluid Y-jet atomizer. The main flow regimes found under the studied operational conditions are annular and wispy annular flow
Iterative Beam Search for Simple Assembly Line Balancing with a Fixed Number of Work Stations
The simple assembly line balancing problem (SALBP) concerns the assignment of
tasks with pre-defined processing times to work stations that are arranged in a
line. Hereby, precedence constraints between the tasks must be respected. The
optimization goal of the SALBP-2 version of the problem concerns the
minimization of the so-called cycle time, that is, the time in which the tasks
of each work station must be completed.
In this work we propose to tackle this problem with an iterative search
method based on beam search. The proposed algorithm is able to obtain optimal,
respectively best-known, solutions in 283 out of 302 test cases. Moreover, for
9 further test cases the algorithm is able to produce new best-known solutions.
These numbers indicate that the proposed iterative beam search algorithm is
currently a state-of-the-art method for the SALBP-2
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