2,897 research outputs found
SoS in Disasters: Why following the manual can be a mistake
According to both the US Geological Survey and the World Bank, 40 billion dollars had been invested in disaster prevention. Natural and human-made disasters that have occurred over the last few years show that there is a gap in disaster prevention caused by the interconnected nature of risks, which cannot be foreseen with current risk management methods. In this paper we point out how disaster management could benefit from a SoS approach in emergency response and preparedness strategies. Using recent disasters as case studies, we identify some keys to success in managing a SoS in preparation, during and in the aftermath of a disaster. In particular, we discuss the idea of the interconnectedness of risks in independent and interdependent systems and the application of Boardman and Sauser’s concept of “creative disobedience”, which are fundamental for goal achievement of systems belonging to a SoS
Application of system dynamics to evaluate the social and economic benefits of infrastructure projects
Published: 29 March 2017Cost-Benefit Analysis (CBA) is often employed to inform decision makers about the desirability of transport infrastructure investment options. One of the main limitations of traditional CBA approaches is that they do not provide a dynamic view that explicitly illustrates the cost and benefit relationships between component entities over time. This paper addresses this issue by describing a System Dynamics (SD) approach that can perform transport infrastructure CBA through the application of systems thinking to develop a causal-loop model that can subsequently be operationalised into an executable stock-and-flow model. Execution of this model readily enables sensitivity analysis of infrastructure investment options and visualisation of the cost-benefit behaviour of each variant over time. The utility of the approach is illustrated through a case study, the Co Chien Bridge project in Vietnam, using a model that incorporates conventional economic metrics and factors that measure indirect project benefits, such as impact on gross domestic product, unemployment rate, and total taxes gained from affected economic sectors.Tiep Nguyen, Stephen Cook and Vernon Irelan
Strong evidence for nucleon resonances near 1900 MeV
Data on the reaction γp → KþΛ from the CLAS experiments are used to derive the leading multipoles,
E0þ, M1−, E1þ, and M1þ, from the production threshold to 2180 MeV in 24 slices of the invariant mass.
The four multipoles are determined without any constraints. The multipoles are fitted using a multichannel
L þ P model that allows us to search for singularities and to extract the positions of poles on the complex
energy plane in an almost model-independent method. The multipoles are also used as additional
constraints in an energy-dependent analysis of a large body of pion and photoinduced reactions within the
Bonn-Gatchina partial wave analysis. The study confirms the existence of poles due to nucleon resonances
with spin parity JP ¼ 1=2−, 1=2þ, and 3=2þ in the region at about 1.9 Ge
The Human Rights & Dignity Experience of Disabled Women during Pregnancy, Childbirth and Early Parenting
Quantum Theory and Galois Fields
We discuss the motivation and main results of a quantum theory over a Galois
field (GFQT). The goal of the paper is to describe main ideas of GFQT in a
simplest possible way and to give clear and simple arguments that GFQT is a
more natural quantum theory than the standard one. The paper has been prepared
as a presentation to the ICSSUR' 2005 conference (Besancon, France, May 2-6,
2005).Comment: Latex, 24 pages, 1 figur
Health care of children
It is estimated that at the present rate of population growth, at least 21,5 million children under the age of 14 years will require health care by the year 2000. With the available medical manpower, it is not possible to provide the present child population with the uniformly high standard of health care to which they are entitled. It is urged that Paediatric Nurse Associates be trained to assist in this regard. A preliminary report of the training scheme introduced for Paediatric Nurse Associates at the Red Cross War Memorial Children's Hospital is presented for discussion and criticism.S. Afr. Med. J., 48, 1752 (1974)
A weakly nonlinear Alfvénic pulse in a transversely inhomogeneous medium
The interaction of a weakly nonlinear Alfvénic pulse with an Alfvén speed inhomogeneity in the direction perpendicular to the magnetic field is investigated. Identical to the phase mixing experienced by a harmonic Alfvén wave, sharp transverse gradients are generated in the pulse by the inhomogeneity. In the initial stage of the evolution of an initially plane Alfvénic pulse, the transverse gradients efficiently generate transversely propagating fast magnetoacoustic waves. However, high resolution full MHD numerical simulations of the developed stage of the pulse evolution show that the generation saturates due to destructive wave interference. It is shown that the weakly non-linear description of the generated fast magnetoacoustic wave is well described by the driven wave equation proposed in Nakariakov et al. (1997), and a simple numerical code (2D MacCromack), which solves it with minimal CPU resources, produces identical results to those obtained from the full MHD code (Lare2d, Arber et al. 2001). A parametric study of the phenomenon is undertaken, showing that, contrary to one's expectations, steeper inhomogeneities of the Alfvén speed do not produce higher saturation levels of the fast wave generation. There is a certain optimal gradient of the inhomogeneity that ensures the maximal efficiency of the fast wave generation
Searching for solar-like oscillations in the delta Scuti star rho Puppis
Despite the shallow convective envelopes of delta Scuti pulsators, solar-like
oscillations are theoretically predicted to be excited in those stars as well.
To search for such stochastic oscillations we organised a spectroscopic
multi-site campaign for the bright, metal-rich delta Sct star rho Puppis. We
obtained a total of 2763 high-resolution spectra using four telescopes. We
discuss the reduction and analysis with the iodine cell technique, developed
for searching for low-amplitude radial velocity variations, in the presence of
high-amplitude variability. Furthermore, we have determined the angular
diameter of rho Puppis to be 1.68 \pm 0.03 mas, translating into a radius of
3.52 \pm 0.07Rsun. Using this value, the frequency of maximum power of possible
solar-like oscillations, is expected at ~43 \pm 2 c/d (498 \pm 23 muHz). The
dominant delta Scuti-type pulsation mode of rho Puppis is known to be the
radial fundamental mode which allows us to determine the mean density of the
star, and therefore an expected large frequency separation of 2.73 c/d (31.6
muHz). We conclude that 1) the radial velocity amplitudes of the delta Scuti
pulsations are different for different spectral lines; 2) we can exclude
solar-like oscillations to be present in rho Puppis with an amplitude per
radial mode larger than 0.5 m/s.Comment: 14 pages, 12 figure, accepted for MNRA
Discovery of spatial periodicities in a coronal loop using automated edge-tracking algorithms
A new method for automated coronal loop tracking, in both spatial and temporal domains, is presented. Applying this technique to TRACE data, obtained using the 171 Å filter on 1998 July 14, we detect a coronal loop undergoing a 270 s kink-mode oscillation, as previously found by Aschwanden et al. However, we also detect flare-induced, and previously unnoticed, spatial periodicities on a scale of 3500 km, which occur along the coronal loop edge. Furthermore, we establish a reduction in oscillatory power for these spatial periodicities of 45% over a 222 s interval. We relate the reduction in detected oscillatory power to the physical damping of these loop-top oscillations
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