Crossover Function Research Articles

Critical Crossover Functions for Simple Fluids: Towards the Crossover Modelling Uniqueness

Based on a single non-universal temperature scaling factor present in a simple fluid case, a detailed analysis of non-universal parameters involved in different critical-to-classical crossover models is given. For the infinite limit of the cutoff wave number, a set of three scaling-parameters is defined for each model such that it shows all the shapes of the theoretical crossover functions overlap on the mean crossover function shapes close to the non-trivial fixed point. The analysis of corresponding links between their fluid-dependent parameters opens a route to define a parametric model of crossover equation-of-state, closely satisfying the universal features calculated from the Ising-like limit in the massive renormalization scheme.

Test of Halperin-Lubensky-Ma crossover function at theN–Sm−Atransition in liquid crystal binary mixtures via high-resolution birefringence measurements

We report optical birefringence data for a series of mixtures of the liquid crystals octylcyanobiphenyl (8CB) and decylcyanobiphenyl (10CB). Nematic order parameter S data in the nematic and smectic A phases have been derived from phase angle changes obtained in temperature scans with a rotating analyzer method. These S values have been used to arrive at values for possible entropy discontinuities at the smectic A to nematic phase transition temperature T_{NA}. The 10CB mole fraction dependence of the obtained entropy discontinuities could be well fitted with a crossover function consistent with the mean-field free-energy expression with a nonzero cubic term arising from the coupling between the smectic-A order parameter and the orientational order parameter director fluctuations in the Halperin-Lubensky-Ma theory. The obtained results are in good agreement with existing results from adiabatic scanning calorimetry. By exploiting the fact that the temperature derivative of the order parameter S(T) near T_{NA} exhibits the same power law divergence as the specific heat capacity, we have extracted the effective critical exponent α values for the compositions under study. The critical exponent α has been observed to reach the tricritical value α_{TCP}=0.5 for the 10CB mole fraction of x=0.330.

Critical Crossover Functions for Simple Fluids: Non-Analytical Scaling Determination of the Ising-Like Crossover Parameter

A non-analytical scaling determination of the Ising-like crossover parameter is proposed considering the critical isochore of a simple fluid at finite distance from its critical temperature. The mean crossover functions, estimated from the bounded results of the massive renormalization scheme in field theory applied to the $$\left( \Phi ^{2}\right) _{d}^{2}\left( n\right) $$ model in three dimensions ( $$d=3$$ ) and scalar order parameter ( $$n=1$$ ), are used to formulate the corresponding scaling equations valid in two well-defined temperature ranges from the critical temperature. The validity range and the Ising-like nature of the corresponding crossover description are discussed in terms of a single Ising-like scale factor characterizing the critical isochore. The asymptotic value of this scale factor can be predicted within the Ising-like preasymptotic domain. Unfortunately, the absence of precise experimental data in such a close vicinity of the critical point leads the direct testing impossible. A contrario, from our scaling equations and the use of precise measurements performed at finite distance from the critical point, its local value can be estimated beyond the Ising-like preasymptotic domain. This non-analytical scaling determination only needs to make reference to the universal features estimated from the mean crossover functions and to introduce a single master dimensionless length common to all the simple fluids. This latter parameter guaranties the uniqueness of the physical length unit used for the theoretical crossover functions and the fluid singular properties when the generalized critical coordinates of the vapor-liquid critical point of each fluid are known. Xenon case along its critical isochore is considered as a typical example to demonstrate the singleness of the Ising-like crossover parameter. With the measurements at finite temperature range of the effective singular behaviors of the isothermal compressibility in the homogeneous domain, and the vapor-liquid coexisting densities in the non homogeneous domain, our scaling equations provide the local estimate of this crossover parameter as a function of the temperature distance from the critical temperature. Our results compare favorably with the single asymptotic value calculated only using four critical coordinates of xenon.

Entanglement entropy from the truncated conformal space

A new numerical approach to entanglement entropies of the Renyi type is proposed for one-dimensional quantum field theories. The method extends the truncated conformal spectrum approach and we will demonstrate that it is especially suited to study the crossover from massless to massive behavior when the subsystem size is comparable to the correlation length. We apply it to different deformations of massless free fermions, corresponding to the scaling limit of the Ising model in transverse and longitudinal fields. For massive free fermions the exactly known crossover function is reproduced already in very small system sizes. The new method treats ground states and excited states on the same footing, and the applicability for excited states is illustrated by reproducing Renyi entropies of low-lying states in the transverse field Ising model.

A Computational Intelligence Method for Effective Diagnosis of Heart Disease using Genetic Algorithm

In recent years improvement of new and effective medical domain applications has vital role in research. Computational Intelligence Systems (CIS) has profound influence in the enlargement of these effective medical field applications and tools. One of the prevalent diseases that world facing is heart disease. The Computational Intelligence Systems uses input clinical data from different knowledge resources throughout the world and applies this data on different computational intelligence tools that uses sophisticated algorithms. The sophisticated algorithms plays prominent role in the construction of medical clinical analysis tools. These tools may be used as an extra aid for the clinical diagnosis of the diseases for the doctors and clinicians. In this paper a novel method for the diagnosis of heart disease has been proposed using Genetic Algorithms. In this approach an effective association rules are inferred using Genetic Algorithm approach which uses tournament selection, crossover, mutation and new proposed fitness function. The Cleaveland data set is used for the experimentation. This data set is collected from the UCI machine learning repository experimental results are prominent when compared with some of the supervised learning techniques.

Finite-size critical scaling in Ising spin glasses in the mean-field regime.

We study in Ising spin glasses the finite-size effects near the spin-glass transition in zero field and at the de Almeida-Thouless transition in a field by Monte Carlo methods and by analytical approximations. In zero field, the finite-size scaling function associated with the spin-glass susceptibility of the Sherrington-Kirkpatrick mean-field spin-glass model is of the same form as that of one-dimensional spin-glass models with power-law long-range interactions in the regime where they can be a proxy for the Edwards-Anderson short-range spin-glass model above the upper critical dimension. We also calculate a simple analytical approximation for the spin-glass susceptibility crossover function. The behavior of the spin-glass susceptibility near the de Almeida-Thouless transition line has also been studied, but here we have only been able to obtain analytically its behavior in the asymptotic limit above and below the transition. We have also simulated the one-dimensional system in a field in the non-mean-field regime to illustrate that when the Imry-Ma droplet length scale exceeds the system size one can then be erroneously lead to conclude that there is a de Almeida-Thouless transition even though it is absent.

Modeling and identification of the multi-axis drive system using support vector machine and granular computing

Advanced manufacturing technology requires high-precision capability in multi-axis computer numerical control (CNC) machine tools. At present, the modeling and identification for the drive system of CNC machine tools has some defects. In order to solve the problem, some interdisciplinary theories and methods, such as support vector machines, granular computing, artificial immune algorithms, and particle swarm optimization algorithms, have been used to model and identify multi-axis drive systems for CNC machine tools. An identification method using a support vector machine, based on granular computing, is presented to identify a multi-axis servo drive system model for improving the precision of model identification, and an immune particle swarm optimization algorithm, based on crossover and mutation functions, is proposed to optimize the structure parameters of the support vector machine based on granular computing. The proposed identification method was evaluated by experiments using the multi-axis servo drive system. The experimental results showed that the proposed approach is capable of improving modeling and identification precision.

An improved uniform design-based genetic algorithm for multi-objective bilevel convex programming

Bilevel programming problems have a nested structure in which two optimisation programming problems are involved, one is the constraints of the other. Among bilevel programming problems, multiobjective bilevel programming problems are applicable but seldom studied. In this paper, a multi-objective bilevel convex programming is considered. To deal with this problem effectively, the lower level is transformed into a single optimisation problem by multiplying by a weighted vector. The vector is generated by scheme of uniform design. By designing a pattern of encoding, initial population generation, uniform design-based crossover, mutation, selection operator and fitness function, an improved uniform design-based genetic algorithm is proposed. Numerical experiments are implemented to test the efficiency of the proposed algorithm with the known results.

An emergency dispatch model considering the urgency of the requirement for reliefs in different disaster areas

Abstract: Purpose: Frequent sudden-onset disasters which have threatened the survival of human and the development of society force the public to pay an increasing attention to emergency management. A challenging task in the process of emergency management is emergency dispatch of reliefs. An emergency dispatch model considering the urgency of the requirement for reliefs in different disaster areas is proposed in this paper to dispatch reliefs reasonably and reduce the effect of sudden-onset disasters. D esign/methodology/approach: Firstly, quantitative assessment on the urgency of the requirement for reliefs in different disaster areas is done by an evaluation method based on Fuzzy Comprehensive Evaluation and improved Evidence Reasoning which is proposed in this paper. And then based the quantitative results, an emergency dispatch model aiming to minimize the response time, the distribution cost and the unsatisfied rate of the requirement for reliefs is proposed, which reflects the requests of disaster areas under emergency, including the urgency of requirement, the economy of distribution and the equity of allocation. Finally, the Genetic Algorithm is improved based on the adaptive crossover and mutation probability function to solve the emergency dispatch model. Findings and Originality/value: A case that the Y hydraulic power enterprise carries on emergency dispatch of reliefs under continuous sudden-onset heavy rain is given to illustrate the availability of the emergency dispatch model proposed in this paper. The results show that the emergency dispatch model meets the distribution priority requirement of disaster area with the higher urgency, so that reliefs are supplied more timely. Research limitations/implications: The emergency dispatch model faced to large scale sudden-onset disasters is complex. The quantity of reliefs that disaster area requires and the running time of vehicles are viewed as available information, and the problem that how to obtain the information is not considered. Practical implications: The emergency dispatch model considering the urgency of the requirement for reliefs in different disaster areas is applicable to a realistic emergency dispatch of reliefs under sudden-onset disasters and the research results is the foundation of further research on the problem of emergency management. Originality/value: This paper proposes emergency dispatch model considering the urgency of the requirement for reliefs in different disaster areas which can meet the realistic requirement that the disaster area with the higher urgency has an priority to obtain the reliefs and make reliefs be distributed timely.

Random walk with random resetting to the maximum position

We study analytically a simple random walk model on a one-dimensional lattice, where at each time step the walker resets to the maximum of the already visited positions (to the rightmost visited site) with a probability r, and with probability (1-r), it undergoes symmetric random walk, i.e., it hops to one of its neighboring sites, with equal probability (1-r)/2. For r=0, it reduces to a standard random walk whose typical distance grows as √n for large n. In the presence of a nonzero resetting rate 0<r≤1, we find that both the average maximum and the average position grow ballistically for large n, with a common speed v(r). Moreover, the fluctuations around their respective averages grow diffusively, again with the same diffusion coefficient D(r). We compute v(r) and D(r) explicitly. We also show that the probability distribution of the difference between the maximum and the location of the walker becomes stationary as n→∞. However, the approach to this stationary distribution is accompanied by a dynamical phase transition, characterized by a weakly singular large deviation function. We also show that r=0 is a special "critical" point, for which the growth laws are different from the r→0 case and we calculate the exact crossover functions that interpolate between the critical (r=0) and the off-critical (r→0) behavior for finite but large n.

Quantum Ising chains with boundary fields

.We present a detailed study of the finite one-dimensional quantum Ising chain in a transverse field in the presence of boundary magnetic fields coupled with the order-parameter spin operator. We consider two magnetic fields located at the boundaries of the chain that have the same strength and that are aligned in the same or in the opposite direction. We derive analytic expressions for the gap in all phases for large values of the chain length L, as a function of the boundary field strength. We also investigate the behaviour of the chain in the quantum ferromagnetic phase for oppositely aligned fields, focusing on the magnet-to-kink transition that occurs at a finite value of the magnetic field strength. At this transition we compute analytically the finite-size crossover functions for the gap, the magnetisation profile, the two-point correlation function, and the density of fermionic modes. As the magnet-to-kink transition is equivalent to the wetting transition in two-dimensional classical Ising models, our results provide new analytic predictions for the finite-size behaviour of Ising systems in a strip geometry at this transition.

Oscillatory Positive Expiratory Pressure in Chronic Obstructive Pulmonary Disease

Evidence-based guidance for the use of airway clearance techniques (ACT) in chronic obstructive pulmonary disease (COPD) is lacking in-part because well-established measurements of pulmonary function such as the forced expiratory volume in 1s (FEV1) are relatively insensitive to ACT. The objective of this crossover study was to evaluate daily use of an oscillatory positive expiratory pressure (oPEP) device for 21–28 days in COPD patients who were self-identified as sputum-producers or non-sputum-producers.COPD volunteers provided written informed consent to daily oPEP use in a randomized crossover fashion. Participants completed baseline, crossover and study-end pulmonary function tests, St. George's Respiratory Questionnaire (SGRQ), Patient Evaluation Questionnaire (PEQ), Six-Minute Walk Test and 3He magnetic resonance imaging (MRI) for the measurement of ventilation abnormalities using the ventilation defect percent (VDP).Fourteen COPD patients, self-identified as sputum-producers and 13 COPD-non-sputum-producers completed the study. Post-oPEP, the PEQ-ease-bringing-up-sputum was improved for sputum-producers (p = 0.005) and non-sputum-producers (p = 0.04), the magnitude of which was greater for sputum-producers (p = 0.03). There were significant post-oPEP improvements for sputum-producers only for FVC (p = 0.01), 6MWD (p = 0.04), SGRQ total score (p = 0.01) as well as PEQ-patient-global-assessment (p = 0.02). Clinically relevant post-oPEP improvements for PEQ-ease-bringing-up-sputum/PEQ-patient-global-assessment/SGRQ/VDP were observed in 8/7/9/6 of 14 sputum-producers and 2/0/3/3 of 13 non-sputum-producers. The post-oPEP change in 3He MRI VDP was related to the change in PEQ-ease-bringing-up-sputum (r = 0.65, p = 0.0004) and FEV1 (r = –0.50, p = 0.009).In COPD patients with chronic sputum production, PEQ and SGRQ scores, FVC and 6MWD improved post-oPEP. FEV1 and PEQ-ease-bringing-up-sputum improvements were related to improved ventilation providing mechanistic evidence to support oPEP use in COPD. Clinical Trials # NCT02282189 and NCT02282202.

Description of heat capacity C v of simple liquids using a thermal equation of state including regular and scaling parts

The p,ρ,T-data for CO2 are approximated in the ranges of 0 < ρ/ρc <2, 217 < T < 430 K, and 0 < p ≤ 25 MPa and for SF6 in the ranges of 0 < ρ/ρc < 2.5, 225 < T < 340 K, and 0 < p ≤ 10 MPa using a new unified equation of state. In this equation, pressure p is an explicit function of ρ and T. It includes a new regular part to approximate p,ρ,T-data in the liquid and gaseous regions of state outside the critical region, a singular part that is a scaling equation of state for the critical region, and a crossover function for combining these equations. The regular part consists of the sum of eight terms with eight constants, three of which are determined by the conditions at the critical point. The total number of system-dependent constants is fourteen, including the critical values of p, ρ, and T. In the scaling part of the equation of state, the critical exponents of the three-dimensional Ising model are used. The mean-square error of the description by pressure of the p,ρ,T-data for CO2 is ±0.63%, and for the p,ρ,T-data obtained for SF6, it is ±0.70% over the entire range of gas and liquid states. Using the constants of the combined equation, heat capacity Cv is calculated at isochores, isotherms, and a binodal, including those in the critical region. The calculation results describes the known experimental data of Cv with an error of ±8%.

Non-renewable Recourses Life Cycles Modeling Aspects

Abstract The task of modeling and forecasting non-renewable resources production using bell-shaped curve-fitting models is considered. Identification of model parameters is based on the genetic algorithm. The purpose of this article is to determine the best genetic algorithm configuration for the task of bell-shaped life cycle models parameters identification. We find the initial population optimal size, and find that heuristic function is the best for crossover and adaptive feasible function is the best for mutation. The experience of modeling 235 time series of oil and gas production is summed up. On the basis of it we made the frequency analysis of models using for every kind of task. It allows to select the preferred models for describing oil, gas and shale gas production at the different levels of aggregation: from a country and a region to a single field.

Optimizing Template for Lookup-Table Inverse Halftoning using Elitist Genetic Algorithm

A template optimization method based on elitist genetic algorithm was proposed for lookup-table inverse halftoning. A mathematical model with constraint conditions was built to describe the template optimization problem. We solved this optimization problem by using elitist genetic algorithm and designed the details about encoding and decoding scheme, selection and reproduce, crossover, mutation, elitist strategy and fitness function according to the proposed optimization model. In experiments, we demonstrated the performance on Floyd-Steinberg error diffusion, Jarvis-Judice error diffusion, cluster dither, Bayer disperse dither and dot diffusion halftone images. According to our experiment study, our method approaches to the optimal result closer than the greedy algorithm and simulated annealing do. We suggested L = 10 on cluster dither images but L = 5 on other four kinds of halftone images.

Crossover Equation of State Models Applied to the Critical Behavior of Xenon

The turbidity (\(\tau \)) measurements of Güttinger and Cannell (Phys Rev A 24:3188–3201, 1981) in the temperature range \(28\,\text {mK}\le T-T_{c}\le 29\,\text {K}\) along the critical isochore of homogeneous xenon are reanalyzed. The singular behaviors of the isothermal compressibility (\(\kappa _{T}\)) and the correlation length (\(\xi \)) predicted from the master crossover functions are introduced in the turbidity functional form derived by Puglielli and Ford (Phys Rev Lett 25:143–146, 1970). We show that the turbidity data are thus well represented by the Ornstein–Zernike approximant, within 1 % precision. We also introduce a new crossover master model (CMM) of the parametric equation of state for a simple fluid system with no adjustable parameter. The CMM model and the phenomenological crossover parametric model are compared with the turbidity data and the coexisting liquid–gas density difference (\(\Delta \rho _{LV}\)). The excellent agreement observed for \(\tau \), \(\kappa _{T}\), \(\xi \), and \(\Delta \rho _{LV}\) in a finite temperature range well beyond the Ising-like preasymptotic domain confirms that the Ising-like critical crossover behavior of xenon can be described in conformity with the universal features estimated by the renormalization-group methods. Only 4 critical coordinates of the vapor–liquid critical point are needed in the (pressure, temperature, molecular volume) phase surface of xenon.

Design and Implementation of Simple Digital Oscilloscope Based on STM32

The digital oscilloscope adopts STM32 MCU as the control core, uses the IDT7201 for memory, through the AD converter ADS830 real-time sampling achieve the extraction of the input signal and digital storage, display; Crossover functions are realized by CPLD to provide accurate clock for MCU, FIFO, ADS830, and communicate with MCU through SPI agreement. Software design to achieve control A/D converter start-up and storage of the sample data, calculate the frequency and amplitude, buttons and LCD screen.Using Altium Designer software to design and produce a digital oscilloscope printed circuit board PCB, and complete the whole production and commissioning. The digital oscilloscope can be real-time accurate sampling and show the general low frequency signal, can be used when using battery power, small volume, convenient to carry, it can be easily integrated into the experiment box, to become a part of it, and other function modules to form a whole.

A Powerful Genetic Algorithm to Crack a Transposition Cipher

Security of information systems depends heavily on the strength of the cryptosystem. Throughout the years, several cryptosystem algorithms have been developed. These algorithms may inherit some weakness that can jeopardize the integrity of the data. In this paper, we present a genetic algorithm to crack a transposition cipher that extends on the notable research in the field and introduces new ideas including a novel crossover function, a dictionary of the most used words in the English language to evaluate the fitness of the keys in any generation, a dynamic selection method, and a variable generating number. This algorithm starts with a very small randomly selected set of keys, and proceeds the crossover operation on the highly fit keys to produce next generations until a specific number of generations, the final result produces a key that is either a perfect match to the original encryption key or one that is very close. Our experiments and results show mostly optimal solutions for the keys in linear time performance which is a dramatic improvement to the brute force algorithm that takes a factorial time to crack the key.

Tumbling of a rigid rod in a shear flow

The tumbling of a rigid rod in a shear flow is analyzed in the high viscosity limit. Following Burgers, the Master Equation is derived for the probability distribution of the orientation of the rod. The equation contains one dimensionless number, the Weissenberg number, which is the ratio of the shear rate and the orientational diffusion constant. The equation is solved for the stationary state distribution for arbitrary Weissenberg numbers, in particular for the limit of high Weissenberg numbers. The stationary state gives an interesting flow pattern for the orientation of the rod, showing the interplay between flow due to the driving shear force and diffusion due to the random thermal forces of the fluid. The average tumbling time and tumbling frequency is calculated as a function of the Weissenberg number. A simple crossover function is proposed which covers the whole regime from small to large Weissenberg numbers.

The Crossover Region Between Long-Range and Short-Range Interactions for the Critical Exponents

It is well know that systems with an interaction decaying as a power of the distance may have critical exponents that are different from those of short-range systems. The boundary between long-range and short-range is known, however the behavior in the crossover region is not well understood. In this paper we propose a general form for the crossover function and we compute it in a particular limit. We compare our predictions with the results of numerical simulations for two-dimensional long-range percolation.