433 research outputs found
Ethical Aspects of Insurance
The nature and ethical basis for insurance in general will be briefly discussed. Reference will then be made to alternatives to insurance as a means for meeting the cost of medical care. Finally, the ethical aspects of private insurance and social insurance will be analyzed as means for paying for health services
Distributed expert systems for ground and space applications
Presented here is the Spacecraft Command Language (SCL) concept of the unification of ground and space operations using a distributed approach. SCL is a hybrid software environment borrowing from expert system technology, fifth generation language development, and multitasking operating system environments. Examples of potential uses for the system and current distributed applications of SCL are given
Spacecraft attitude control using a smart control system
Traditionally, spacecraft attitude control has been implemented using control loops written in native code for a space hardened processor. The Naval Research Lab has taken this approach during the development of the Attitude Control Electronics (ACE) package. After the system was developed and delivered, NRL decided to explore alternate technologies to accomplish this same task more efficiently. The approach taken by NRL was to implement the ACE control loops using systems technologies. The purpose of this effort was to: (1) research capabilities required of an expert system in processing a classic closed-loop control algorithm; (2) research the development environment required to design and test an embedded expert systems environment; (3) research the complexity of design and development of expert systems versus a conventional approach; and (4) test the resulting systems against the flight acceptance test software for both response and accuracy. Two expert systems were selected to implement the control loops. Criteria used for the selection of the expert systems included that they had to run in both embedded systems and ground based environments. Using two different expert systems allowed a comparison of the real-time capabilities, inferencing capabilities, and the ground-based development environment. The two expert systems chosen for the evaluation were Spacecraft Command Language (SCL), and NEXTPERT Object. SCL is a smart control system produced for the NRL by Interface and Control Systems (ICS). SCL was developed to be used for real-time command, control, and monitoring of a new generation of spacecraft. NEXPERT Object is a commercially available product developed by Neuron Data. Results of the effort were evaluated using the ACE test bed. The ACE test bed had been developed and used to test the original flight hardware and software using simulators and flight-like interfaces. The test bed was used for testing the expert systems in a 'near-flight' environment. The technical approach, the system architecture, the development environments, knowledge base development, and results of this effort are detailed
Urban Parcel Logistics Hub and Network Design: The Impact of Modularity and Hyperconnectivity
This paper examines how exploiting the hyperconnectivity and modularity concepts underpinning the Physical Internet enables the parcel logistics industry to meet the worldwide challenges to efficiently and sustainably offer faster and more precise deliveries across urban agglomerations, notably across the world’s megacities. It emphasizes disruptive transformations of package logistics hubs and networks, such as multi-tier world pixelization, multi-plane parcel logistics web, smart dynamic parcel routing and hub-based consolidation, and modular parcel containerization
Indirect Dark Matter Detection from Dwarf Satellites: Joint Expectations from Astrophysics and Supersymmetry
We present a general methodology for determining the gamma-ray flux from
annihilation of dark matter particles in Milky Way satellite galaxies, focusing
on two promising satellites as examples: Segue 1 and Draco. We use the
SuperBayeS code to explore the best-fitting regions of the Constrained Minimal
Supersymmetric Standard Model (CMSSM) parameter space, and an independent MCMC
analysis of the dark matter halo properties of the satellites using published
radial velocities. We present a formalism for determining the boost from halo
substructure in these galaxies and show that its value depends strongly on the
extrapolation of the concentration-mass (c(M)) relation for CDM subhalos down
to the minimum possible mass. We show that the preferred region for this
minimum halo mass within the CMSSM with neutralino dark matter is ~10^-9-10^-6
solar masses. For the boost model where the observed power-law c(M) relation is
extrapolated down to the minimum halo mass we find average boosts of about 20,
while the Bullock et al (2001) c(M) model results in boosts of order unity. We
estimate that for the power-law c(M) boost model and photon energies greater
than a GeV, the Fermi space-telescope has about 20% chance of detecting a dark
matter annihilation signal from Draco with signal-to-noise greater than 3 after
about 5 years of observation
Combination of RGD Compound and Low-Dose Paclitaxel Induces Apoptosis in Human Glioblastoma Cells
) peptide, to human glioblastoma U87MG cells with combination of low dose Paclitaxel (PTX) pre-treatment to augment therapeutic activity for RGD peptide-induced apoptosis. peptide induced U87MG programmed cell death. The increased expression of PTX-induced integrin-αvβ3 was correlated with the enhanced apoptosis in U87MG cells.This study provides a novel concept of targeting integrin-αvβ3 with RGD peptides in combination with low-dose PTX pre-treatment to improve efficiency in human glioblastoma treatment
Gravothermal collapse of isolated self-interacting dark matter haloes: N-body simulation versus the fluid model
Self-Interacting Dark Matter (SIDM) is a collisional form of cold dark matter
(CDM), originally proposed to solve problems that arose when the collisionless
CDM theory of structure formation was compared with observations of galaxies on
small scales. The quantitative impact of the proposed elastic collisions on
structure formation has been estimated previously by Monte Carlo N-body
simulations and by a conducting fluid model, with apparently diverging results.
To improve this situation, we make direct comparisons between new Monte Carlo
N-body simulations and solutions of the conducting fluid model, for isolated
SIDM haloes of fixed mass. This allows us to separate cleanly the effects of
gravothermal relaxation from those of continuous mass accretion in an expanding
background universe. When these two methods were previously applied to halo
formation with cosmological boundary conditions, they disagreed by an order of
magnitude about the size of the scattering cross section required to solve the
so-called 'cusp-core problem.' We show here, however, that the methods agree
with each other within 20 per cent for isolated haloes. This suggests that the
two methods are consistent, and that their disagreement for cosmological haloes
is not caused by a breakdown of their validity.
The isolated haloes studied here undergo gravothermal collapse. We compare
the solutions calculated by these two methods for gravothermal collapse
starting from several initial conditions. This allows us to calibrate the heat
conduction which accounts for the effect of elastic hard-sphere scattering in
the fluid model. The amount of tuning of the thermal conductivity parameters
required to bring the two methods into close agreement for isolated haloes,
however, is too small to explain the discrepancy found previously in the
cosmological context.Comment: 14 pages, 10 figures, accepted for publication on MNRA
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