Miracle-dz/UniFAR-FTUs huggingface dataset:
Generalized cross entropy method for analysing the SERVQUAL model

The aim of this paper is to define a new approach for the analysis of data collected by means of SERVQUAL questionnaires which is based on the generalized cross entropy (GCE) approach. In this respect, we firstly give a short review about the important role that SERVQUAL plays in the analysis of service quality as well as in the assessment of the competitiveness of public and private organizations. Secondly, we provide a formal definition of GCE approach together with a brief discussion about its features and usefulness. Finally, we show the application of GCE for a SERVQUAL model, based on a patients’ satisfaction case study and we discuss the results obtained by using the proposed GCE-SERVQUAL methodology.
One-channel time-reversal in chaotic cavities: Theoretical limits

One-channel time-reversal experiments in closed chaotic cavities produce excellent, but not perfect, time-reversed focusing. This paper investigates such experiments by a simple eigenmode analysis of the system. It shows that the process is, even for long reversed signals, subject to an information loss during recording and re-emission which prevents perfect time-reversal. This fact can be expressed by a simple equation, called the cavity equation, which states that the signal of a one-channel time-reversal is equal to the signal of a perfect time-reversal after convolution with the backscattering impulse response of the reversal point (i.e., from this point to this point). The latter convolution describes the introduction of the loss of information. Furthermore, arguments are presented suggesting that one third of the total energy of the time-reversed wave field is actually contained in the refocusing wavefront. The predictions are verified by numerical finite-difference time-domain simulations.
ON CONTROL LAWS FOR VEHICLE SUSPENSIONS ACCOUNTING FOR INPUT CORRELATIONS

SUMMARY Input correlations involving time delays are common in active vehicle suspension system problems. One approach to control law derivation fur such systems is to restrict attention to slate feedback laws in the interests of practicality and it is then of interest to determine the law which is, in some sense, the best. Under assumptions which are common in this area. relating to input, system and cost Function forms, a new derivation of the expression for the cost, accounting for time delays, is given. The use of the expression in numerical procedures for determining effective control gains is discussed and an example for a half car planar vehicle model is described. By comparing results with existing ones which are truly optimal, an estimate is made of the loss of performance which results from the restriction of the control law form in this case. Some generalisation of the results is attempted and they are placed in a contemporary context at the conclusion.
Prospects for Habitable “Earths” in Known Exoplanetary Systems

We have examined whether putative Earth-mass planets could remain confined to the habitable zones (HZs) of the 111 exoplanetary systems confirmed by 2004 August. We find that in about half of these systems there could be confinement for at least the past 1000 Myr, though in some cases only in variously restricted regions of the HZ. The HZ migrates outward during the main-sequence lifetime, and we find that in about two-thirds of the systems an Earth-mass planet could be confined to the HZ for at least 1000 Myr sometime during the main-sequence lifetime. Clearly, these systems should be high on the target list for exploration for terrestrial planets. We have reached our conclusions by detailed investigations of seven systems, which has resulted in an estimate of the distance from the giant planet within which orbital stability is unlikely for an Earth-mass planet. This distance is given by nRH, where RH is the Hill radius of the giant planet and n is a multiplier that depends on the giant's orbital eccentricity and on whether the Earth-mass planet is interior or exterior to the giant planet. We have estimated n for each of the seven systems by launching Earth-mass planets in various orbits and following their fate with a hybrid orbital integrator. We have then evaluated the habitability of the other exoplanetary systems using nRH derived from the giant's orbital eccentricity without carrying out time-consuming orbital integrations. A stellar evolution model has been used to obtain the HZs throughout the main-sequence lifetime.
Chorus source locations from VLF Poynting flux measurements with the Polar spacecraft

Previous studies have used indirect evidence to argue that whistler‐mode chorus emissions are generated near the magnetic equator. In this paper a spatial survey of wave normals and Poynting vectors computed from three‐component electric and magnetic field measurements is used to show that chorus is generated very close to the magnetic equator. One surprising result is that there are almost no chorus emissions propagating toward the magnetic equator, such as might be expected from high‐latitude magnetospheric reflections. The absence of a reflected component indicates that the chorus is reabsorbed, probably by Landau damping, before returning to the magnetic equatorial plane.
H∞ control via measurement feedback for general nonlinear systems

This paper shows how the problem of (local) disturbance attenuation via measurement feedback, with internal stability, can be solved for a nonlinear system of rather general structure. The solution of the problem is shown to be related to the existence of solutions of a pair of Hamilton-Jacobi inequalities in n independent variables, which are associated with state-feedback and, respectively, output-injection design. >
A Confidence Interval and Test for the Mean of an Asymmetric Distribution

ABSTRACT A confidence interval and test are obtained for the mean of an asymmetric distribution using a random sample of size n. The method is based on N. J. Johnson's (1978) modified t-test, where terms of Cornish–Fisher expansions involving the third moment are used to adjust the conventional statistic to have more closely a Student's t-distribution with n − 1 degrees of freedom. Johnson's (1978) test cannot be inverted uniquely, so a corresponding confidence interval for the mean may be disjointed. However, an artificial term of small order can be added to make inversion of the test a uniquely defined operation, which prevents such disjointedness. The resulting one-sided and two-sided intervals perform better than others in the literature with skewed distributions, and have good performance with a normal distribution. The two-sided interval may be recommended for general use if the sample size is 10 or more and the nominal confidence coefficient is 95% or less, or if the sample size is 30 or more and the confidence coefficient is 99% or less.
Asymptotic Solution of Moment Approximation of the Particle Population Balance Equation for Brownian Agglomeration

In the present study, the asymptotic solutions for particle moment approximation of population balance equation for Brownian agglomeration have been obtained analytically. At long time, the dimensionless particle moment (MC) is an explicit monotonic decreasing function of fractal dimension in the free molecule regime, while it is a constant in the continuum regime. The asymptotic agglomerate growth rate is consistent with previous qualitative analysis and numerical solution, but the present asymptotic solution is more concise and straightforward. Copyright 2015 American Association for Aerosol Research
Experimental Implementation on Vibration Mode Control of a Moving 3-PRR Flexible Parallel Manipulator with Multiple PZT Transducers

This paper presents the experimental implementation of active vibration control applied to a moving 3-PRR parallel manipulator with three flexible links. The active vibration control is implemented using three piezoelectric (PZT) transducer pairs applied to one flexible intermediate link based on modal strain rate feedback (MSRF) control. A real-time active vibration control system is developed using two PCs with LabVIEW Real-Time. Modal analyses are conducted, and the results demonstrate that the vibration modes of the intermediate links are dynamically coupled and the vibration frequency components are complicated and closely spaced. Simplified and efficient modal filters are developed to extract modal coordinates in real time, and a second order compensator is used to filter amplified noises and unmodeled high frequency dynamics. A MSRF controller is then designed using an independent mode space control strategy, and is implemented experimentally with the first mode targeted for control. Experimental results demonstrate that the vibration amplitude of the first vibration mode of the intermediate link is significantly reduced using three PZT control pairs. The experimental results using one PZT control pair and two control pairs are provided to justify the use of three PZT control pairs.
A branch-and-bound algorithm to minimize total tardiness with different release dates

This article deals with the scheduling problem for minimizing total tardiness with unequal release dates. A set of jobs have to be scheduled on a machine able to perform only one job at a time. No preemptive job is allowed. This problem has been proven to be NP-hard. We prove some dominance properties, and provide a lower bound polynomially computed for this problem. On the basis of our previous results, we propose a branch-and-bound algorithm to solve the problem. This algorithm was tested on hard problems involving 30 jobs and also on relatively easy problems with up to 230 jobs. Detailed computational results are given.
Special relativity as a simple geometry problem

The null result of the Michelson–Morley experiment and the constancy of the one-way speed of light in the ‘rest system’ are used to formulate a simple problem, to be solved by elementary geometry techniques using a pair of compasses and non-graduated rulers. The solution consists of a drawing allowing a direct visualization of all the fundamental effects of standard relativistic kinematics, namely time dilation, length contraction and relativity of simultaneity. Moreover, it also provides an immediate image of other important and more subtle aspects, often passed by in relativity courses, such as the conventionality of simultaneity thesis, possible non-invariance of the one-way speed of light and compatibility between the Lorentz–Poincaré and Einstein–Minkowski philosophies. The geometric scheme so constructed constitutes a powerful tool to clearly illustrate both traditional and not-so-traditional aspects of special relativity teaching.
Calculations of self-excited impinging jet flow

This paper presents numerical calculations of the self-excited oscillations of an incompressible planar jet impinging upon a wedge for a Reynolds-number range of 250–650. For this Reynolds-number range these flows are experimentally observed to be two-dimensional and laminar. A finite-difference vorticity/stream-function formulation of the Navier-Stokes equations is employed. The self-sustained flow oscillations result in not just one but several well-defined flow frequency components due to nonlinear interaction of two primary components: the most unstable frequency (β) of the jet shear layer and a low-frequency modulating component ($\frac{1}{3}\beta $). The modulating component results from vortex-vortex interaction at the impingement edge of both like and counter-rotating vortices. Although the interaction pattern varies through the Reynolds-number range studied, the pattern adjusts itself to maintain the modulating component $\frac{1}{3}\beta $ which has a strong upstream influence. The numerical results, in agreement with experimental results, strongly suggest the occurrence of such phenomena as frequency jumps and hysteresis. Pressure at the wedge surface has been calculated and compared with experimental results. Numerical results for wedge torque and lift, which have not been experimentally measured, have also been obtained.
Robustness Studies in Covariance Structure Modeling

In covariance structure modeling, several estimation methods are available. The robustness of an estimator against specific violations of assumptions can be determined empirically by means of a Monte Carlo study. Many such studies in covariance structure analysis have been published, but the conclusions frequently seem to contradict each other. An overview of robustness studies in covariance structure analysis is given, and an attempt is made to generalize findings. Robustness studies are described and distinguished from each other systematically by means of certain characteristics. These characteristics serve as explanatory variables in a meta-analysis concerning the behavior of parameter estimators, standard error estimators, and goodness-of-fit statistics when the model is correctly specified.
Axisymmetric static and dynamic analysis of laminated hollow cylinders composed of monoclinic elastic layers

This paper deals with axisymmetric static and dynamic deformations of laminated hollow cylinders composed of an arbitrary number of monoclinic layers. The analysis is based on a successive approximation approach employed earlier by the authors for corresponding studies dealing with homogeneous orthotropic and cross-ply laminated cylinders. In the axisymmetric static case, where alternative approaches exist in the literature, the efficiency of the proposed approach is tested by means of comparisons of corresponding numerical results. However, the main purpose of the paper is an exact, three-dimensional, free vibration analysis of such angle-ply laminated cylinders. For this problem that has not as yet been considered in the literature, numerical results are presented and discussed for relatively thick cylinders having a regular symmetric or a regular antisymmetric angle-ply lay-up.
Numerical vs Cardinal Measurements in Multiattribute Decision Making: How Exact Is Enough?

Abstract Multiattribute decision making can involve consideration of both quantitative and qualitative measures of criteria attaintment. Some decision support systems (decision aids) to help multiattribute decision making quantify value functions. One of the most popular of these systems, multiattribute utility theory (MAUT), requires two types of input. Decision makers need to express the relative value of different attainment levels on each criterion, as well as express the relative importance of these criteria. Some systems (such as DECAID) require simple direct graphical input of value and criterion importance. Other systems (such as LOGICAL DECISION) use more complex means of expressing relative value. Either way, MAUT converts expressions of criterion importance into quantitative form. This study compares the relative stability of numerical results obtained through two decision support systems, DECAID and LOGICAL DECISION (LD), used in the task of evaluation of multiattribute alternatives. Additionally the relative stability of results was measured by comparison with results obtained using an ordinal method, ZAPROS. ZAPROS is a decision support system for construction of a partial order over the set of alternatives. It does not require conversion of qualitative measures into quantitative form. The relations among alternatives are close to those based on ordinal dominance. The results of experiments show that ordinal relationships between task parameters are much more stable than those obtained from quantitative measures. Results from DECAID and LD are much less coincident with each other than with results obtained through ZAPROS. Many inconsistencies were found in subject responses. It is concluded that more attention should be given to the means of testing judgment consistency, and that in some cases, attempts to solve decision tasks through more "exact" judgments of value function parameters may lead to erroneous results.
WEAK ERGODICITY OF NONHOMOGENEOUS MARKOV CHAINS ON NONCOMMUTATIVE L 1 -SPACES

In this paper we study certain properties of Dobrushin's ergod- icity coe�cient for stochastic operators de�ned on noncommutative L 1 -spaces associated with semi-�nite von Neumann algebras. Such results extends the well-known classical ones to a noncommutative setting. This allows us to in- vestigate the weak ergodicity of nonhomogeneous discrete Markov processes (NDMP) by means of the ergodicity coe�cient. We provide a su�cient condi- tions for such processes to satisfy the weak ergodicity. Moreover, a necessary and su�cient condition is given for the satisfaction of the L 1 -weak ergodicity of NDMP. It is also provided an example showing that L 1 -weak ergodicity is weaker that weak ergodicity. We applied the main results to several concrete examples of noncommutative NDMP.
A Comparison of n Estimators for the Binomial Distribution

Abstract Estimating the number, n, of trials, given a sequence of independent success counts obtained by replicating the n-trial experiment is less studied and a considerably harder problem than estimating p for the binomial distribution. Both the method of moments and the maximum likelihood estimators of n are considered. When p is unknown and small, while n is large, both estimators become highly unstable. Stabilized versions of these estimators are proposed, and their performance is described in terms of results obtained by simulation.
Prediction of propagation characteristics of photonic crystal fibers by a simpler, more complete and versatile formulation of their effective cladding indices

Abstract. We present a simpler, more complete and versatile formulation for the effective cladding index of a solid-core photonic crystal fiber (PCF) with a triangular lattice of air holes in the cladding region. This index depends on two fundamental geometrical parameters: the air hole diameters and their separation in the endlessly single mode region of the PCF corresponding to a prescribed upper limit of relative air hole size as well as the wavelength of the light used. Our earlier available formulation for the normalized propagation constants of the infinite cladding region of the same PCF and hence its effective cladding index takes care only of the dependence on the relative air hole size and wavelength at a particular hole pitch. Now, the hole pitch dependence is also taken into account to make the formulation complete in all senses. The proposed new formulation is shown to be accurate on the basis of a comparison of our results with those obtained by available techniques. Further, to check its validity in different problems of practical interest, we apply our new formulation to evaluate various propagation characteristics of the PCF. On comparison with the previously available results, our results are seen to agree excellently with them. The formulation should find wide use for simple verification by system designers and users.
A survey of interstellar H I from L-alpha absorption measurements. II

The Copernicus satellite surveyed the spectral region near L alpha to obtain column densities of interstellar HI toward 100 stars. The distance to 10 stars exceeds 2 kpc and 34 stars lie beyond 1 kpc. Stars with color excess E(B-V) up to 0.5 mag are observed. The value of the mean ratio of total neutral hydrogen to color excess was found to equal 5.8 x 10 to the 21st power atoms per (sq cm x mag). For stars with accurate E(B-V), the deviations from this mean are generally less than a factor of 1.5. A notable exception is the dark cloud star, rho Oph. A reduction in visual reddening efficiency for the grains that are larger than normal in the rho Oph dark cloud probably explains this result. The conversion of atomic hydrogen into molecular form in dense clouds was observed in the gas to E(B-V) correlation plots. The best estimate for the mean total gas density for clouds and the intercloud medium, as a whole, in the solar neighborhood and in the plane of the galaxy is 1.15 atoms per cu. cm; those for the atomic gas and molecular gas alone are 0.86 atoms per cu cm and 0.143more » molecules per cu cm respectively. For the intercloud medium, where molecular hydrogen is a negligible fraction of the total gas, atomic gas density was found to equal 0.16 atoms per cu cm with a Gaussian scale height perpendicular to the plane of about 350 pc, as derived from high latitude stars. « less
Complexity in charge transport for multiwalled carbon nanotube and poly(methyl methacrylate) composites

We report on studies of the charge transport mechanism of the composites of multiwalled carbon nanotubes MWCNTs and poly methyl methacrylatePMMA. The MWCNTs were synthesized by a chemical vapor deposition method using Fe as a catalyst. The dc conductivity dc and its temperature dependence dcT were measured in a temperature range of 0.5– 300 K to study the charge transport mechanism of the composites. The dc of composites at room temperature increased as the MWCNT concentration increased, which shows typical percolation behavior with percolation threshold of pc at 0.4 wt % of the MWCNTs. The dcT of the MWCNT-PMMA composites were fitted to the combination of Sheng’s fluctuation induced tunneling FIT model and the one-dimensional variable range hopping 1D VRH model. The tunneling mechanism and the 1D VRH transport were attributed to the charge tunneling between MWCNT clusters and the charge hopping through 1D MWCNTs, respectively. Magnetoresistance MR of MWCNT-PMMA composites was measured up to 9 T of magnetic field. The results of MR and dcT showed that the FIT model was dominant in the low temperature region T 10 K, while the 1D VRH process became dominant as the temperature increased 10 KT 300 K. We observed unusually large negative MR in the composites at the lower temperatures T 4K due to FIT conduction. We related the parameters specifying charge transport to the percolation structures of MWCNT-PMMA composites based on the results of temperature dependence of dc and of the MR.
ON A CLASS OF PLUG-IN METHODS OF BANDWIDTH SELECTION FOR KERNEL DENSITY ESTIMATORS

In this paper we deal with the problem of global bandwith selection for kernel density estimators. We introduce a class of plug-in selection rules for the bandwidth and examine the asymptotic behaviour of them. These rules are based on a kernel estimator for f(f^(t))dt (y > 2 is an even integer) where / is the density we want to estimate. As an auxiliary result, we prove a statement on the strong approximation of the kernel estimators for /(/M(í ) ) 2 dí .