2,546 research outputs found
Finite-Time Adaptive Fuzzy Tracking Control for Nonlinear State Constrained Pure-Feedback Systems
This paper investigates the finite-time adaptive fuzzy tracking control
problem for a class of pure-feedback system with full-state constraints. With
the help of Mean-Value Theorem, the pure-feedback nonlinear system is
transformed into strict-feedback case. By employing finite-time-stable like
function and state transformation for output tracking error, the output
tracking error converges to a predefined set in a fixed finite interval. To
tackle the problem of state constraints, integral Barrier Lyapunov functions
are utilized to guarantee that the state variables remain within the prescribed
constraints with feasibility check. Fuzzy logic systems are utilized to
approximate the unknown nonlinear functions. In addition, all the signals in
the closed-loop system are guaranteed to be semi-global ultimately uniformly
bounded. Finally, two simulation examples are given to show the effectiveness
of the proposed control strategy
The Impact of Customer Profile and Customer Participation on Customer Relationship Management Performance
There are two main sources of knowledge about customers: customer profile and customer participation. The companies use information technologies to analyze the customer profiles and extract tacit knowledge about customer via customer participation. The result of this experiment demonstrates that the use of customer profile improves customers’ perception on goods quality and increase the effectiveness of Customer Relationship Management (CRM). In addition, customer participation can improve customers’ perception on goods quality and enhance performance of CRM through perceived participation. The result indicates that the customer profiles and customer participation are two crucial factors for companies to maintain customer relationship
Optimizing mixture properties of biodiesel production using genetic algorithm-based evolutionary support vector machine
Nowadays, biodiesel is used as one of the alternative renewable energy due to the increasing energy demand. However, optimum production of biodiesel still requires a huge number of expensive and time-consuming laboratory tests. To address the problem, this research develops a novel Genetic Algorithm-based Evolutionary Support Vector Machine (GA-ESIM). The GA-ESIM is an Artificial Intelligence (AI)-based tool that combines K-means Chaotic Genetic Algorithm (KCGA) and Evolutionary Support Vector Machine Inference Model (ESIM). The ESIM is utilized as a supervised learning technique to establish a highly accurate prediction model between the input--output of biodiesel mixture properties; and the KCGA is used to perform the simulation to obtain the optimum mixture properties based on the prediction model. A real biodiesel experimental data is provided to validate the GA-ESIM performance. Our simulation results demonstrate that the GA-ESIM establishes a prediction model with better accuracy than other AI-based tool and thus obtains the mixture properties with the biodiesel yield of 99.9%, higher than the best experimental data record, 97.4%
Spatial heterogeneity of tectonic stress and friction in the crust: new evidence from earthquake focal mechanisms in Taiwan
We performed inversions of earthquake focal mechanisms in central Taiwan to investigate the heterogeneity of the stress field and fault strength, and temporal variations of stress parameters, friction and pore pressure associated with the 1999 Chi-Chi earthquake. We divided the focal mechanism data into two groups: before and after the Chi-Chi earthquake, and analysed them separately. With the assumption of a uniform stress field, the friction coefficient is mostly within a range of 0.2–0.4 in central Taiwan, which is lower than the commonly quoted laboratory result, 0.6–0.85. The low friction coefficient is also inferred by the rotation of principal stress axes after the Chi-Chi earthquake. By contrast, if we assume that the friction is constant and failures occur on optimally oriented planes, we find that the resulting stress orientations must be spatially variable. However, a large dispersion of stress orientations is not seen in borehole breakouts and fault slip data, implying a constant friction model might be ruled out. Our analysis suggests that either the distribution of the coefficient of friction or pore pressure changed during the 1999 Chi-Chi earthquake. We infer that the pore pressure probably rose in the Chi-Chi rupture area and northern Longitudinal Valley and dropped in the areas south of the coseismic rupture area after the main shock
Effects of Stress Evolution Process on the Thermal Stability of Thin Accretion Discs
The stress evolution process is taken into account in the linear stability
analysis of standard thin accretion discs. We find that the growth rate of
thermally unstable modes can decrease significantly owing to the stress delay,
which may help to understand the quasi-periodic variability of GRS 1915+105. We
also discuss possible application of stress evolution to the stability of
Shapiro-Lightman-Eardley disc.Comment: 5 pages, 2 figures, accepted by MNRA
Triaqua(2-{[(E)-5-formyl-2-oxidobenzylidene]amino}ethanesulfonato)cobalt(II) dihydrate
The title compound, [Co(C10H9NO5S)(H2O)3]·2H2O, is a cobalt–Schiff base complex derived from taurine. There are two complex molecules and four solvent water molecules in the asymmetric unit. The central Co atom is six coordinated by two O atoms and one N atom of the ligand and three O atoms of water molecules, forming a slightly distorted octahedral geometry. The crystal structure is stabilized by several O—H⋯O hydrogen bonds
Variability of the giant X-ray bump in GRB 121027A and possible origin
The particular giant X-ray bump of GRB 121027A triggered by \emph{Swift} is
quite different from the typical X-ray flares in gamma-ray bursts. There
exhibit four parts of the observed structural variabilities in the rise and
decay phase of the bump. Considering the quality of four parts of the data, we
can only analyze the data from about 5300 s to about 6100 s in the bump using
the stepwise filter correlation method (Gao et al. 2012), and find that the
periodic oscillation may exist, which is confirmed by
the Lomb-Scargle method (Scargle 1982). Furthermore, a jet precession model
(Liu et al. 2010) is proposed to account for such a variability.Comment: 5 pages, 3 figures, accepted for publication in MNRA
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