219,543 research outputs found
Revisiting the Rice Theorem of Cellular Automata
A cellular automaton is a parallel synchronous computing model, which
consists in a juxtaposition of finite automata whose state evolves according to
that of their neighbors. It induces a dynamical system on the set of
configurations, i.e. the infinite sequences of cell states. The limit set of
the cellular automaton is the set of configurations which can be reached
arbitrarily late in the evolution.
In this paper, we prove that all properties of limit sets of cellular
automata with binary-state cells are undecidable, except surjectivity. This is
a refinement of the classical "Rice Theorem" that Kari proved on cellular
automata with arbitrary state sets.Comment: 12 pages conference STACS'1
Symmetric angular momentum coupling, the quantum volume operator and the 7-spin network: a computational perspective
A unified vision of the symmetric coupling of angular momenta and of the
quantum mechanical volume operator is illustrated. The focus is on the quantum
mechanical angular momentum theory of Wigner's 6j symbols and on the volume
operator of the symmetric coupling in spin network approaches: here, crucial to
our presentation are an appreciation of the role of the Racah sum rule and the
simplification arising from the use of Regge symmetry. The projective geometry
approach permits the introduction of a symmetric representation of a network of
seven spins or angular momenta. Results of extensive computational
investigations are summarized, presented and briefly discussed.Comment: 15 pages, 10 figures, presented at ICCSA 2014, 14th International
Conference on Computational Science and Application
A Proof of the Factorization Forest Theorem
We show that for every homomorphism where is a finite
semigroup there exists a factorization forest of height \leq 3 \abs{S}. The
proof is based on Green's relations.Comment: 4 page
Band stop filter with a synthetic inductor with series resistance and a real operational amplifier
This paper deals with application of simple
synthetic inductor with series resistance (non-ideal gyrator).
Those inductors are seldom used. However, if
we use this inductor in the arm of bridge, the circuit
is able to achieve high performance. In this way we
can get band stop filter with good performance. In the
paper we solve influence of real OPA properties. Theoretical
considerations are verified by means of simulations
(MicroCap) and experiments. Based on theoretical
considerations, simulations and experiments are
finally determined by criteria that must meet real operational
amplifier to make the circuit performed well
Topics in Cement and Concrete Research
In recent decades, the construction sector has faced many changes. One of these changes is the shift in the role of national government from one-sided practices in which the government was solely responsible for strategic and long-term spatial planning to a multi-actor and multi-level arena. One outcome was a rearrangement of the balance between public and private responsibilities. This has led to new procurement routes and contracts as Private Finance Initiative (PFI) and Public Private Partnerships (PPP), as well as to a more performance-oriented client (both public and private). At the same time, construction firms changed their strategic focus from cost efficiency to adding value for money for the client, resulting in new contract forms such as Design & Construct (D&C), Building, Operate & Transfer (BOT) and variants there from. So far, governments of most European countries have their own restrictive specifications for the use of building materials
Theory and simulation of short-range models of globular protein solutions
We report theoretical and simulation studies of phase coexistence in model
globular protein solutions, based on short-range, central, pair potential
representations of the interaction among macro-particles. After reviewing our
previous investigations of hard-core Yukawa and generalised Lennard-Jones
potentials, we report more recent results obtained within a DLVO-like
description of lysozyme solutions in water and added salt. We show that a
one-parameter fit of this model based on Static Light Scattering and
Self-Interaction Chromatography data in the dilute protein regime, yields
demixing and crystallization curves in good agreement with experimental
protein-rich/protein-poor and solubility envelopes. The dependence of cloud and
solubility points temperature of the model on the ionic strength is also
investigated. Our findings highlight the minimal assumptions on the properties
of the microscopic interaction sufficient for a satisfactory reproduction of
the phase diagram topology of globular protein solutions.Comment: 17 pages, 8 figures, Proc. of Conference "Structural Arrest
Transitions in Colloidal Systems with Short-Range Attractions", Messina
(ITALY) 17-20 December 200
DNA nanotweezers studied with a coarse-grained model of DNA
We introduce a coarse-grained rigid nucleotide model of DNA that reproduces
the basic thermodynamics of short strands: duplex hybridization,
single-stranded stacking and hairpin formation, and also captures the essential
structural properties of DNA: the helical pitch, persistence length and
torsional stiffness of double-stranded molecules, as well as the comparative
flexibility of unstacked single strands. We apply the model to calculate the
detailed free-energy landscape of one full cycle of DNA 'tweezers', a simple
machine driven by hybridization and strand displacement.Comment: 4 pages, 5 figure
Modelling of a roof runoff harvesting system: The use of rainwater for toilet flushing
The water balance of a four-people family rainwater harvesting system was calculated in a case study. The experimental water saving efficiency (WSE) was calculated as 87 %. A simple computer model was implemented to simulate the behaviour of the rainwater harvesting system. In general, the rainwater collector volumes predicted by the daily model had shown a good correlation with the experimental values. The difference between the experimental and the predicted values for the stored volume can be explained by the lack of maintenance of the system that can affect its performance. On the basis of a long-term simulation of 20-year rainfall data, the following parameters were calculated: rainfall, water demand, mains water, rainwater used, over-flow and WSE. The collection of rainwater from roofs, its storage and subsequent use for toilet flushing can save 42 m3 of potable water per year for the studied system. The model was also used to find the optimal size of the tank for the single-family household: a storage capacity of approximately 5 m3 was found to be appropriate. The storage capacity and tank size were distinguished. The importance to take into account the dead volume of the tank for the sizing was indeed highlighted
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