1,189 research outputs found
Computationally efficient simulation in urban mechanised tunnelling based on multi-level BIM models
The design of complex underground infrastructure projects involves various empirical, analytical or numerical models with different levels of complexity. The use of simulation models in current state-of-the-art tunnel design process can be cumbersome when significant manual, time-consuming preparation, analysis and excessive computing resources are required. This paper addresses the challenges connected with minimising the user workload and computational time, as well as enabling real-time computations during the construction. To ensure a seamless workflow during design and to minimise the computation time of the analysis, we propose a novel concept for BIM-based numerical simulations, enabling the modelling of the tunnel advance on different levels of detail in terms of geometrical representation, material modelling and modelling of the advancement process. To ensure computational efficiency, the simulation software has been developed with special emphasis on efficient implementation, including parallelisation strategies on shared and distributed memory systems. For real-time on-demand calculations, simulation based meta models are integrated into the software platform. The components of the BIM-based multi-level simulation concept are described and evaluated in detail by means of representative numerical examples
Automatic Verification of Transactions on an Object-Oriented Database
In the context of the object-oriented data model, a compiletime approach is given that provides for a significant reduction of the amount of run-time transaction overhead due to integrity constraint checking. The higher-order logic Isabelle theorem prover is used to automatically prove which constraints might, or might not be violated by a given transaction in a manner analogous to the one used by Sheard and Stemple (1989) for the relational data model. A prototype transaction verification tool has been implemented, which automates the semantic mappings and generates proof goals for Isabelle. Test results are discussed to illustrate the effectiveness of our approach
Molecular Spin Qudits for Quantum Algorithms
Presently, one of the most ambitious technological goals is the development
of devices working under the laws of quantum mechanics. One prominent target is
the quantum computer, which would allow the processing of information at
quantum level for purposes not achievable with even the most powerful computer
resources. The large-scale implementation of quantum information would be a
game changer for current technology, because it would allow unprecedented
parallelised computation and secure encryption based on the principles of
quantum superposition and entanglement. Currently, there are several physical
platforms racing to achieve the level of performance required for the quantum
hardware to step into the realm of practical quantum information applications.
Several materials have been proposed to fulfil this task, ranging from quantum
dots, Bose-Einstein condensates, spin impurities, superconducting circuits,
molecules, amongst others. Magnetic molecules are among the list of promising
building blocks, due to (i) their intrinsic monodispersity, (ii) discrete
energy levels (iii) the possibility of chemical quantum state engineering, and
(iv) their multilevel characteristics, leading to the so called Qudits (d > 2),
amongst others. Herein we review how a molecular multilevel nuclear spin qubit
(or qudit, where d = 4), known as TbPc2, gathers all the necessary requirements
to perform as a molecular hardware platform with a first generation of
molecular devices enabling even quantum algorithm operations.Comment: Chem. Soc. Rev., 2017, Advance Articl
Sketch-a-Net that Beats Humans
We propose a multi-scale multi-channel deep neural network framework that,
for the first time, yields sketch recognition performance surpassing that of
humans. Our superior performance is a result of explicitly embedding the unique
characteristics of sketches in our model: (i) a network architecture designed
for sketch rather than natural photo statistics, (ii) a multi-channel
generalisation that encodes sequential ordering in the sketching process, and
(iii) a multi-scale network ensemble with joint Bayesian fusion that accounts
for the different levels of abstraction exhibited in free-hand sketches. We
show that state-of-the-art deep networks specifically engineered for photos of
natural objects fail to perform well on sketch recognition, regardless whether
they are trained using photo or sketch. Our network on the other hand not only
delivers the best performance on the largest human sketch dataset to date, but
also is small in size making efficient training possible using just CPUs.Comment: Accepted to BMVC 2015 (oral
A method for the architectural design of distributed control systems for large, civil jet engines: a systems engineering approach
The design of distributed control systems (DCSs) for large, civil gas turbine engines is a complex
architectural challenge. To date, the majority of research into DCSs has focused on the contributing
technologies and high temperature electronics rather than the architecture of the system itself. This
thesis proposes a method for the architectural design of distributed systems using a genetic algorithm to
generate, evaluate and refine designs. The proposed designs are analysed for their architectural quality,
lifecycle value and commercial benefit. The method is presented along with results proving the concept.
Whilst the method described here is applied exclusively to Distributed Control System (DCS) for jet
engines, the principles and methods could be adapted for a broad range of complex systems
Swarm Intelligence
Swarm Intelligence has emerged as one of the most studied artificial intelligence branches during the last decade, constituting the fastest growing stream in the bio-inspired computation community. A clear trend can be deduced analyzing some of the most renowned scientific databases available, showing that the interest aroused by this branch has increased at a notable pace in the last years. This book describes the prominent theories and recent developments of Swarm Intelligence methods, and their application in all fields covered by engineering. This book unleashes a great opportunity for researchers, lecturers, and practitioners interested in Swarm Intelligence, optimization problems, and artificial intelligence
Development of a new quantum trajectory molecular dynamics framework
An extension to the wave packet description of quantum plasmas is presented,
where the wave packet can be elongated in arbitrary directions. A generalised
Ewald summation is constructed for the wave packet models accounting for
long-range Coulomb interactions and fermionic effects are approximated by
purpose-built Pauli potentials, self-consistent with the wave packets used. We
demonstrate its numerical implementation with good parallel support and close
to linear scaling in particle number, used for comparisons with the more common
wave packet employing isotropic states. Ground state and thermal properties are
compared between the models with differences occurring primarily in the
electronic subsystem. Especially, the electrical conductivity of dense hydrogen
is investigated where a 15% increase in DC conductivity can be seen in our wave
packet model compared to other models.Comment: 20 pages, 6 figure
- âŠ