1,393 research outputs found
Triggered memory-based swarm optimization in dynamic environments
This is a post-print version of this article - Copyright @ 2007 Springer-VerlagIn recent years, there has been an increasing concern from the evolutionary computation community on dynamic optimization problems since many real-world optimization problems are time-varying. In this paper, a triggered memory scheme is introduced into the particle swarm optimization to deal with dynamic environments. The triggered memory scheme enhances traditional memory scheme with a triggered memory generator. Experimental study over a benchmark dynamic problem shows that the triggered memory-based particle swarm optimization algorithm has stronger robustness and adaptability than traditional particle swarm optimization algorithms, both with and without traditional memory scheme, for dynamic optimization problems
Theory and Application of Dissociative Electron Capture in Molecular Identification
The coupling of an electron monochromator (EM) to a mass spectrometer (MS)
has created a new analytical technique, EM-MS, for the investigation of
electrophilic compounds. This method provides a powerful tool for molecular
identification of compounds contained in complex matrices, such as
environmental samples. EM-MS expands the application and selectivity of
traditional MS through the inclusion of a new dimension in the space of
molecular characteristics--the electron resonance energy spectrum. However,
before this tool can realize its full potential, it will be necessary to create
a library of resonance energy scans from standards of the molecules for which
EM-MS offers a practical means of detection. Here, an approach supplementing
direct measurement with chemical inference and quantum scattering theory is
presented to demonstrate the feasibility of directly calculating resonance
energy spectra. This approach makes use of the symmetry of the
transition-matrix element of the captured electron to discriminate between the
spectra of isomers. As a way of validating this approach, the resonance values
for twenty-five nitrated aromatic compounds were measured along with their
relative abundance. Subsequently, the spectra for the isomers of nitrotoluene
were shown to be consistent with the symmetry-based model. The initial success
of this treatment suggests that it might be possible to predict negative ion
resonances and thus create a library of EM-MS standards.Comment: 18 pages, 7 figure
Adaptive intelligence applied to numerical optimisation
The article presents modification strategies theoretical comparison and experimental results achieved by adaptive heuristics applied to numerical optimisation of several non-constraint test functions. The aims of the study are to identify and compare how adaptive search heuristics behave within heterogeneous search space without retuning of the search parameters. The achieved results are summarised and analysed, which could be used for comparison to other methods and further investigation
Characterization of Pump-Induced Acoustics in Space Launch System Main Propulsion System Liquid Hydrogen Feedline Using Airflow Test Data
High intensity acoustic edgetones located upstream of the RS-25 Low Pressure Fuel Turbo Pump (LPFTP) were previously observed during Space Launch System (STS) airflow testing of a model Main Propulsion System (MPS) liquid hydrogen (LH2) feedline mated to a modified LPFTP. MPS hardware has been adapted to mitigate the problematic edgetones as part of the Space Launch System (SLS) program. A follow-on airflow test campaign has subjected the adapted hardware to tests mimicking STS-era airflow conditions, and this manuscript describes acoustic environment identification and characterization born from the latest test results. Fluid dynamics responsible for driving discrete excitations were well reproduced using legacy hardware. The modified design was found insensitive to high intensity edgetone-like discretes over the bandwidth of interest to SLS MPS unsteady environments. Rather, the natural acoustics of the test article were observed to respond in a narrowband-random/mixed discrete manner to broadband noise thought generated by the flow field. The intensity of these responses were several orders of magnitude reduced from those driven by edgetones
An Efficient Algorithm for Optimizing Adaptive Quantum Metrology Processes
Quantum-enhanced metrology infers an unknown quantity with accuracy beyond
the standard quantum limit (SQL). Feedback-based metrological techniques are
promising for beating the SQL but devising the feedback procedures is difficult
and inefficient. Here we introduce an efficient self-learning
swarm-intelligence algorithm for devising feedback-based quantum metrological
procedures. Our algorithm can be trained with simulated or real-world trials
and accommodates experimental imperfections, losses, and decoherence
The continuity of the inversion and the structure of maximal subgroups in countably compact topological semigroups
In this paper we search for conditions on a countably compact
(pseudo-compact) topological semigroup under which: (i) each maximal subgroup
in is a (closed) topological subgroup in ; (ii) the Clifford part
(i.e. the union of all maximal subgroups) of the semigroup is a
closed subset in ; (iii) the inversion is continuous; and (iv) the projection ,
, onto the subset of idempotents of ,
is continuous
Pharmacokinetic Characterisation and Comparison of Bioavailability of Intranasal Fentanyl, Transmucosal, and Intravenous Administration through a Three-Way Crossover Study in 24 Healthy Volunteers
Background. For more than 60 years, the synthetic opioid fentanyl has been widely used in anaesthesia and analgesia. While the intravenous formulation is primarily used for general anaesthesia and intensive care settings, the drug’s high lipophilic properties also allow various noninvasive routes of administration. Published data suggest that intranasal administration is also attractive for use as intranasal patient-controlled analgesia (PCA). A newly developed intranasal fentanyl formulation containing 47 μg fentanyl, intravenous fentanyl, and oral transmucosal fentanyl citrate were characterised, and bioavailability was compared to assess the suitability of the intranasal formulation for an intranasal PCA product. Methods. 27 healthy volunteers were enrolled in a single-centre, open-label, randomised (order of treatments), single-dose study in a three-period crossover design. The pharmacokinetics of one intranasal puff of fentanyl formulation (47 μg, 140 mL per puff), one short intravenous infusion of 50 μg fentanyl, and one lozenge with an integrated applicator (200 μg fentanyl) were studied, and bioavailability was calculated. Blood samples were collected over 12 hours, and plasma concentrations of fentanyl were determined by HPLC with MS/MS detection. Results. 24 volunteers completed the study. The geometric mean of AUC0-tlast was the highest with oral transmucosal administration (1106 h pg/ml, CV% = 32.86), followed by intravenous (672 h pg/ml, CV% = 32.18) and intranasal administration (515 h pg/ml, CV% = 30.10). Cmax was 886 pg/ml (CV% = 59.38) for intravenous, 338 pg/ml (CV% = 45.61) for intranasal, and 310 pg/ml (CV% = 29.58) for oral transmucosal administration. tmax was shortest for intravenous administration (0.06 h, SD = 0.056), followed by intranasal (0.21 h, SD = 0.078) and oral transmucosal administration (1.20 h, SD = 0.763). Dose-adjusted absolute bioavailability was determined to be 74.70% for the intranasal formulation and 41.25% for the oral transmucosal product. In total, 38 adverse events (AEs) occurred. Fourteen AEs were potentially related to the investigational items. No serious AE occurred. Conclusion. Pharmacokinetic parameters and bioavailability of the investigated intranasal fentanyl indicated suitability for its intended use as an intranasal PCA option
Topological monoids of monotone injective partial selfmaps of with cofinite domain and image
In this paper we study the semigroup
of partial cofinal monotone
bijective transformations of the set of positive integers . We show
that the semigroup has algebraic
properties similar to the bicyclic semigroup: it is bisimple and all of its
non-trivial group homomorphisms are either isomorphisms or group homomorphisms.
We also prove that every locally compact topology on
such that
is a topological inverse
semigroup, is discrete. Finally, we describe the closure of
in a topological
semigroup
State Transition Algorithm
In terms of the concepts of state and state transition, a new heuristic
random search algorithm named state transition algorithm is proposed. For
continuous function optimization problems, four special transformation
operators called rotation, translation, expansion and axesion are designed.
Adjusting measures of the transformations are mainly studied to keep the
balance of exploration and exploitation. Convergence analysis is also discussed
about the algorithm based on random search theory. In the meanwhile, to
strengthen the search ability in high dimensional space, communication strategy
is introduced into the basic algorithm and intermittent exchange is presented
to prevent premature convergence. Finally, experiments are carried out for the
algorithms. With 10 common benchmark unconstrained continuous functions used to
test the performance, the results show that state transition algorithms are
promising algorithms due to their good global search capability and convergence
property when compared with some popular algorithms.Comment: 18 pages, 28 figure
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