1,371 research outputs found
Executive computer program for linking independent computer programs: ODINEX
Program controls sequence of execution of network of program elements and maintains data base of common information which forms communication link among them. Approach is applicable to any multiple-program task
High performance dash on warning air mobile, missile system
An aircraft-missile system which performs a high acceleration takeoff followed by a supersonic dash to a 'safe' distance from the launch site is presented. Topics considered are: (1) technological feasibility to the dash on warning concept; (2) aircraft and boost trajectory requirements; and (3) partial cost estimates for a fleet of aircraft which provide 200 missiles on airborne alert. Various aircraft boost propulsion systems were studied such as an unstaged cryogenic rocket, an unstaged storable liquid, and a solid rocket staged system. Various wing planforms were also studied. Vehicle gross weights are given. The results indicate that the dash on warning concept will meet expected performance criteria, and can be implemented using existing technology, such as all-aluminum aircraft and existing high-bypass-ratio turbofan engines
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Rapid Manufactured Textiles
Rapid Manufacturing (RM) is increasingly becoming a viable manufacturing process due
to dramatic advantages that are achievable in the area of design complexity. Through the
exploration of the design freedom, this paper introduces the concept of manufacturing textiles for
potential smart and high performance textile applications. This paper discusses the current
limitations associated with the manufacture of textiles through RM and presents a novel
methodology for the generation of 3D conformal RM textile articles. The paper concludes that
through RM it is entirely possible to manufacture a structure that incorporates drape and free
movement properties directly comparable to conventional textiles.Mechanical Engineerin
Gap modification of atomically thin boron nitride by phonon mediated interactions
A theory is presented for the modification of bandgaps in atomically thin
boron nitride (BN) by attractive interactions mediated through phonons in a
polarizable substrate, or in the BN plane. Gap equations are solved, and gap
enhancements are found to range up to 70% for dimensionless electron-phonon
coupling \lambda=1, indicating that a proportion of the measured BN bandgap may
have a phonon origin
A holistic multi-scale approach to using 3D scanning technology in accident reconstruction
Three-dimensional scanning and documentation methods are becoming increasingly employed by law enforcement personnel for crime scene and accident scene recording. Three-dimensional documentation of the victim’s body in such cases is also increasingly used as the field of forensic radiology and imaging is expanding rapidly. These scanning technologies enable a more complete and detailed documentation than standard autopsy. This was used to examine a fatal pedestrian-vehicle collision where the pedestrian was killed by a van whilst crossing the road. Two competing scenarios were considered for the vehicle speed calculation: the pedestrian being projected forward by the impact or the pedestrian being carried on the vehicle’s bonnet. In order to assist with this, the impact area of the accident vehicle was scanned using laser surface scanning, the victim was scanned using postmortem CT and micro-CT and the data sets were combined to virtually match features of the vehicle to injuries on the victim. Micro-CT revealed additional injuries not previously detected, lending support to the pedestrian-carry theory
Unboundedness and downward closures of higher-order pushdown automata
We show the diagonal problem for higher-order pushdown automata (HOPDA), and
hence the simultaneous unboundedness problem, is decidable. From recent work by
Zetzsche this means that we can construct the downward closure of the set of
words accepted by a given HOPDA. This also means we can construct the downward
closure of the Parikh image of a HOPDA. Both of these consequences play an
important role in verifying concurrent higher-order programs expressed as HOPDA
or safe higher-order recursion schemes
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A Hybrid Algorithm for Topology Optimization of Additive Manufactured Structures
Most topology (TO) algorithms involve the penalization of intricate structural features to eliminate manufacturing difficulties. Since additive manufacturing is less dependent on manufacturing
constraints, it becomes necessary to adapt these algorithms for AM. We propose a hybrid algorithm
consisting of an adaptive meshing strategy (AMS) and a modified form of the bidirectional evolutionary structural optimization (BESO) method. By solving a standard cantilever problem, we show
that the hybrid method offers improved performance over the standard BESO method. It is proposed
that the new method is more suitable for optimizing structures for AM in a computational efficient
manner.Mechanical Engineerin
Rise of the centrist: from binary to continuous opinion dynamics
We propose a model that extends the binary ``united we stand, divided we
fall'' opinion dynamics of Sznajd-Weron to handle continuous and multi-state
discrete opinions. Disagreement dynamics are often ignored in continuous
extensions of the binary rules, so we make the most symmetric continuum
extension of the binary model that can treat the consequences of agreement
(debate) and disagreement (confrontation) within a population of agents. We use
the continuum extension as an opportunity to develop rules for persistence of
opinion (memory). Rules governing the propagation of centrist views are also
examined. Monte Carlo simulations are carried out. We find that both memory
effects and the type of centrist significantly modify the variance of average
opinions in the large timescale limits of the models. Finally, we describe the
limit of applicability for Sznajd-Weron's model of binary opinions as the
continuum limit is approached. By comparing Monte Carlo results and long
time-step limits, we find that the opinion dynamics of binary models are
significantly different to those where agents are permitted more than 3
opinions
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