Miracle-dz/UniFAR-FTUs huggingface dataset:
Text mining analysis on students’ expectations and anxieties towards data analytics course

Abstract The lack of understanding of course expectations and student anxieties in a Data Analytics course creates a significant gap in the practice of teaching and learning the course. This study investigated course expectations and anxieties of college students in Data Analytics courses offered over three semesters. A total of 2,893-word essays from 91 students were analyzed using text mining methods to achieve this goal. It was discovered that students understood the course but only associated its application to the field of business. Using hierarchical cluster analysis, students’ course expectations were classified into three themes: the goal of data analytics; the skills that would be acquired in the course; and the application of data analytics. Sentiment analysis disclosed that the students had apprehensions about the course because of its complex, meticulous, and mathematical nature. There were more positive than negative notions about the course. Implications of the findings and future work are offered.
Opportunism in Chinese Interfirm Alliances: Effects of Asymmetric Dependence and Guanxi Governance

Abstract In alliance studies, opportunism is generally considered a critical obstacle to interfirm cooperation, as it hampers interfirm confidence, impedes alliance evolution, and increases the probability of alliance failure. This study extends the prior opportunism studies by hypothesizing that actor opportunism in Chinese business will be largely affected by two sets of interfirm relationships: partners’ asymmetric dependence and guanxi governance. Data from 109 alliances undertaken by Taiwanese information and electronic firms supported the research hypotheses.
Orbital magnetization in dilute ferromagnetic semiconductors

The relationship between the modern and classical Landau's approach to carrier orbital magnetization is studied theoretically within the envelope function approximation, taking ferromagnetic (Ga,Mn)As as an example. It is shown that while the evaluation of hole magnetization within the modern theory does not require information on the band structure in a magnetic field, the number of basis wave functions must be much larger than in the Landau approach to achieve the same quantitative accuracy. A numerically efficient method is proposed, which takes advantages of these two theoretical schemes. The computed magnitude of orbital magnetization is in accord with experimental values obtained by x-ray magnetic circular dichroism in (III,Mn)V compounds. The direct effect of the magnetic field on the hole spectrum is studied too, and employed to interpret a dependence of the Coulomb blockade maxima on the magnetic field in a single electron transistor with a (Ga,Mn)As gate.
Dimension of attractors and invariant sets in reaction diffusion equations

Under fairly general assumptions, we prove that every compact invariant set $\mathcal I$ of the semiflow generated by the semilinear reaction diffusion equation u_t+\beta(x)u-\Delta u&=f(x,u),&&(t,x)\in[0,+\infty[\times\Omega, u&=0,&&(t,x)\in[0,+\infty[\times\partial\Omega} {equation*} in $H^1_0(\Omega)$ has finite Hausdorff dimension. Here $\Omega$ is an arbitrary, possibly unbounded, domain in $\R^3$ and $f(x,u)$ is a nonlinearity of subcritical growth. The nonlinearity $f(x,u)$ needs not to satisfy any dissipativeness assumption and the invariant subset $\mathcal I$ needs not to be an an attractor. If $\Omega$ is regular, $f(x,u)$ is dissipative and $\mathcal I$ is the global attractor, we give an explicit bound on the Hausdorff dimension of $\mathcal I$ in terms of the structure parameter of the equation.
Dynamics and statistical mechanics of point vortices in bounded domains

A general treatment of the dynamics and statistical mechanics of point vortices in bounded domains is introduced in Chapter 1. Chapter 2 then considers high positive energy statistical mechanics of 2D Euler vortices. In this case, the most-probable equilibrium dynamics are given by solutions of the sinh-Poisson equation and a particular heart-shaped domain is found in which below a critical energy the solution has a dipolar structure and above it a monopolar structure. Sinh-Poisson predictions are compared to long-time averages of dynamical simulations of the $N$ vortex system in the same domain. Chapter 3 introduces a new algorithm (VOR-MFS) for the solution of generalised point vortex dynamics in an arbitrary domain. The algorithm only requires knowledge of the free-space Green's function and utilises the exponentially convergent method of fundamental solutions to obtain an approximation to the vortex Hamiltonian by solution of an appropriate boundary value problem. A number of test cases are presented, including quasi-geostrophic shallow water (QGSW) point vortex motion (governed by a Bessel function). Chapter 4 concerns low energy (positive and negative) statistical mechanics of QGSW vortices in `Neumann oval' domains. In this case, the `vorticity fluctuation equation' -- analogous to the sinh-Poisson equation -- is derived and solved to give expressions for key thermodynamic quantities. These theoretical expressions are compared with results from direct sampling of the microcanonical ensemble, using VOR-MFS to calculate the energy of the QGSW system. Chapter 5 considers the distribution of 2D Euler vortices in a Neumann oval. At high energies, vortices of one sign cluster in one lobe of the domain and vortices of the other sign cluster in the other lobe. For long-time simulations, these clusters are found to switch lobes. This behaviour is verified using results from the microcanonical ensemble.
Towards surpassing the standard quantum limit using optical springs

The existence of Gravitational waves is a prediction that arose from Einstein's theory of general relativity. So far their direct detection has eluded scientists with Einstein himself believing they would never be detected. However, recent developments in advanced interferometric detectors should allow the first detections to be made when they are commissioned later this decade. This will open up an entire new field of astronomy giving deeper understanding to the physics of and proving Einstein's general theory of relativity. Astronomers always want bigger telescopes whether it is to see further or to see more detail and this will no doubt occur with gravitational wave telescopes. Hence, further improvements in sensitivity will be required. This thesis examines techniques for improving sensitivity beyond the standard quantum limit, a future limit to sensitivity, using optical rigidity. By coupling two suspended cavity mirrors together using only the light circulating between them the response of the system changes such that a linear restoring force is created on both cavity optics, the "optical spring". The first experiment carried out in the scope of this thesis shows how an intentionally applied signal that changes the position of the input mirror in a rigidly coupled cavity is transferred via the optical spring to a position change of the output cavity mirror. A small independent interferometer, a so-called local readout, is used to monitor the displacement of the output cavity mirror allowing the position of the input mirror to be inferred. This experiment verifies that it is possible to gather information on the position of the input mirror via the local readout interferometer the photons of which have never interacted with the input mirror. The local readout device was able to measure a coupled motion between the cavity mirrors, via the optical spring, of 10
Effect of different interlayer on Al 5052/SS 316 explosive cladding

Abstract The study presents the microstructural and strength characteristics of Al5052/SS316 explosive clads interlaced with different interlayer (aluminium 1100/SS 304/copper) by varying standoff distance (6 and 8 mm), loading ratio, R (mass of explosive/mass of flyer plate: 0.6 and 0.8) and preset angle between flyer and interlayer (6 and 8°), A. The interface microstructure shows the transformation of an uninterrupted melted layer formed in conventional cladding (no interlayer) into a thin or no reaction product clad, when an interlayer is introduced. Similarly, the kinetic energy utilization (1.26 –1.79 MJ/m2) and deformation work (0.76 –1.10 MJ/m2) during explosive cladding increase. The explosive clads having an interlayer exhibit higher mechanical strength than the interlayer less explosive clads and the highest strength (RTS: 263 MPa; Ss: 175 MPa) was witnessed for Al 5052/SS 304/SS316 explosive clads at higher parametric levels.
Quantum centipedes: collective dynamics of interacting quantum walkers

We consider the quantum centipede made of N fermionic quantum walkers on the one-dimensional lattice interacting by means of the simplest of all hard-bound constraints: the distance between two consecutive fermions is either one or two lattice spacings. This composite quantum walker spreads ballistically, just as the simple quantum walk. However, because of the interactions between the internal degrees of freedom, the distribution of its center-of-mass velocity displays numerous ballistic fronts in the long-time limit, corresponding to singularities in the empirical velocity distribution. The spectrum of the centipede and the corresponding group velocities are analyzed by direct means for the first few values of N. Some analytical results are obtained for arbitrary N by exploiting an exact mapping of the problem onto a free-fermion system. We thus derive the maximal velocity describing the ballistic spreading of the two extremal fronts of the centipede wavefunction, including its non-trivial value in the large-N limit.
Higher dimensional nonlinear massive gravity

Inspired by a recent ghost-free nonlinear massive gravity in four-dimensional spacetime, we study its higher dimensional scenarios. As a result, we are able to show the constant-like behavior of massive graviton terms for some well-known metrics such as the Friedmann-Lemaitre-Robertson-Walker, Bianchi type I, and Schwarzschild-Tangherlini-(A)dS metrics in a specific five-dimensional nonlinear massive gravity under an assumption that its fiducial metrics are compatible with physical ones. In addition, some simple cosmological solutions of the five-dimensional massive gravity will be figured out consistently.
Analysis of the breakage parameters of railway ballast based on the discrete element method

目的 有砟轨道在长期服役下频繁出现道砟颗粒掉角、破碎等劣化现象,降低了有砟轨道的稳定性。 而道砟的破碎与其形状、大小、应力状态等有较大的关系,因此合理确定道砟的破碎参数是研究和解决这一问题的关键。 本文旨在探索基于Hertz-Mindlin本构模型的道砟破碎参数,研究道砟的破碎性能,以期为实际服役的铁路有砟轨道提供参考。 创新点 1. 采用统计学方法分析了道砟破碎的主要影响因素及其临界压碎强度和临界剪碎强度;2. 采用响应面法确定了离散元道砟的最优破碎参数组合;3. 通过直剪试验分析了道砟的抗剪性能和破碎状况,为实际服役的有砟轨道提供参考。 方法 1. 通过单轴压缩破碎和单轴剪切破碎实测试验,确定简单应力状态下道砟破碎的主要影响因素及其临界压碎强度和临界剪碎强度（图1和2,表3）;2. 建立可破碎道砟的精细化离散元模型,采用Box-Behnken法进行仿真试验的工况设计,并对仿真试验结果进行响应曲面分析以获取最优破碎参数（图9,表7）;3. 通过对比实测与仿真的直剪试验结果,验证离散元道砟破碎参数的正确性,并探明道砟堆积体的抗剪性能（图12和13）。 结论 1. 对于粒径范围为22.4~63.0 mm的道砟,其压碎特征应力和剪碎特征应力受道砟粒径的影响不大,而受道砟形状的影响较大;2. 针状道砟更容易破碎;3. 直剪试验中,道砟的累积破碎率逐渐增大,最终达到13.97%;4. 道砟的最优破碎参数可参考本研究的结论进行取值,且具有较高的应用价值。 During the service lives of ballasted tracks, the ballast experiences degradation, such as breakage and fragmentation, which reduces the stability of the tracks. Ballast breakage is directly related to the shapes, sizes, and stress states of particles. The key to solving this problem is to determine the breakage parameters of railway ballast. In this study, through uniaxial compression and uniaxial shear tests, the factors associated with ballast breakage for a simple stress state were obtained. Then, a refined discrete element model of railway ballast was established. The Box-Behnken method was used to design a simulation test, and a response surface method was used to obtain the optimal ballast breakage parameters. Lastly, the results of a direct shear test were compared with the simulation results to verify the correctness of the parameters and to study the shear resistance of the ballast aggregates. The results showed that for ballast particles with sizes of 22.4–63.0 mm, the characteristic stresses of compression and shear were not significantly affected by the size of the particles, but were greatly affected by their shape. In particular, long particles were more likely to break. During the direct shear test, the cumulative ballast breakage ratio gradually increased to 13.97%. The optimal breakage parameters of the ballast determined by this approach have high application value in the management of ballasted tracks.
Frequency domain analysis of learning systems

Frequency domain arguments on a general learning law are presented to verify claims of convergence which relax earlier requirements on the learning law transfer function. Known convergence properties are used to develop a pole-placement interpretation for an example for which simulations using a proportional-derivative learning law form are carried out. Physically relevant disturbances are introduced, and the ability of the learning law to damp out their effects is studied. A significant state-dependent disturbance is shown to be attenuated for reliable trajectory tracking. <<ETX>>
The evolution of the AGN content in groups up to z ~ 1

Context. We explore the AGN content in groups in the two GOODS fields (North and South), exploiting the ultra-deep 2 and 4 Msec Chandra data and the deep multiwavelength observations from optical to mid IR available for both fields. Aims. Determining the AGN content in structures of di! erent mass/velocity dispersion and comparing them to higher mass/lower redshift analogs is important to understand how the AGN formation process is related to environmental properties. Methods. We use our well-tested cluster finding algorithm to identify structures in the two GOODS fields, exploiting the available spectroscopic redshifts as well as accurate photometric redshifts. We identify 9 structures in GOODS-south (already presented in a previous paper) and 8 new structures in the GOODS-north field. We only consider structures where at least 2/3 of the members brighter than MR = " 20 have a spectroscopic redshift. We then check if any of the group members coincides with X-ray sources that belong to the 4 and 2 Msec source catalogs respectively, and with a simple classification based on total rest-frame hard luminosity and hardness ratio we determine if the X-ray emission originates from AGN activity or it is more probably related to the galaxies’ star-formation activity. Results. We find that the fraction of AGN with LogLH > 42ergs " 1 in galaxies with MR < " 20 varies from less than 5% to 22% with an average value of 6.3±1.3%, i.e. much higher than the value found for lower redshift groups of similar mass, which is just 1%. It is also more than double the fraction found for massive clusters at a similar high redshift (z # 1). We then explore the spatial distribution of AGN in the structures and find that they preferentially populate the outer regions rather than the center. The colors of AGN host galaxies in structures tend to be confined to the green valley, thus avoiding the blue cloud and partially also the red-sequence, contrary to what happens in the field. We finally compare our results to the predictions of two sets of semi analytic models to investigate the evolution of AGN and evaluate potential triggering and fueling mechanisms. The outcome of this comparison attests the importance of galaxy encounters, not necessarily leading to mergers, as an e" cient AGN triggering mechanism.
A study of elliptical last stable orbits about a massive Kerr black hole

The last stable orbit (LSO) of a compact object (CO) is an important boundary condition when performing numerical analysis of orbit evolution. Although the LSO is already well understood for the case where a test particle is in an elliptical orbit around a Schwarzschild black hole (SBH) and for the case of a circular orbit about a Kerr black hole (KBH) of normalized spin, (|J|/M2, where J is the spin angular momentum of the KBH); it is worthwhile to extend our knowledge to include elliptical orbits about a KBH. This extension helps to lay the foundation for a better understanding of gravitational wave (GW) emission. The mathematical developments described in this work sprang from the use of an effective potential derived from the Kerr metric, which encapsulates the Lense–Thirring precession. This allowed us to develop a new form of analytical expression to calculate the LSO Radius for circular orbits (RLSO) of arbitrary KBH spin. We were then able to construct a numerical method to calculate the latus rectum for an elliptical LSO. Formulae for (square of normalized orbital energy) and (square of normalized orbital angular momentum) in terms of eccentricity, ε, and latus rectum, , were previously developed by others for elliptical orbits around an SBH and then extended to the KBH case; we used these results to generalize our analytical equations to elliptical orbits. LSO data calculated from our analytical equations and numerical procedures, and those previously published, are then compared and found to be in excellent agreement.
Light propagation through weakly scattering media: a study of Monte Carlo vs. diffusion theory with application to neuroimaging

One of the major challenges within Optical Imaging, photon propagation through clear layers embedded between scattering tissues, can be now efficiently modelled in real-time thanks to the Monte Carlo approach based on GPU. Because of its nature, the photon propagation problem can be very easily parallelized and ran on low cost hardware, avoiding the need for expensive Super Computers. A comparison between Diffusion and MC photon propagation theory is presented in this work with application to neuroimaging, investigating low scattering regions in a mouse-like phantom. Regions such as the Cerebral Spinal Fluid, are currently not taken into account in the classical computational models because of the impossibility to accurately simulate light propagation using fast Diffusive Equation approaches, leading to inaccuracies during the reconstruction process. The goal of the study presented here, is to reduce and further improve the computation accuracy of the reconstructed solution in a highly realistic scenario in the case of neuroimaging in preclinical mouse models.
Software Defect Prediction through Neural Network and Feature Selections

Software failure such as software defect causes billion of dollar loss every year. Software failure also affects billion of people worldwide. Inadequate software testing can cause software failure. To predict the software defect, this study proposed a model consisting of feature selection and classifications. The correlation base method was used for feature selection, and radial base function neural network (RBF) was used for classification. Also, for testing the proposed system, fourteen NASA data sets were used including CM1, JM1, KC1, KC2, KC3, KC4, MC1, MC2, MW1, PC1, PC2, PC3, PC4, and PC5. The data set was divided using the well-known K-cross-validation methods which were performed to divide the data set for training and testing the RBF. The RBF were trained and tested before and after feature selections. Precision, recall, F-measure, and accuracy are four methods used to evaluate the performance of the proposed methods. The precision obtained for the fourteen data sets was CM1, 94.01%; JM1, 85.18%; KC1, 83.24%; KC2, 81.27%; KC3, 79.30%; KC4, 85.29%; MC1, 99.89%; MC2, 73.27%; MW1, 90.90%; PC1, 98.79%; PC2, 100%; PC3, 95.67%; PC4, 95.12%; and PC5, 80.89%. Recall was as follows: CM1, 95.78%; JM1, 87.89%; KC1, 86.24%; KC2, 83.82%; KC3, 82.10%; KC4, 86.28%; MC1, 100%; MC2, 76.67%; MW1, 92.09%; PC1, 99.98%; PC2, 100%; PC3, 96.23%; PC4, 95.17%; and PC5, 81.80%. F-measure was as follows: CM1, 0.95; JM1, 0.87; KC1, 0.83; KC2, 0.82; KC3, 0.85; KC4, 0.86; MC1, 0.99; MC2, 0.76; MW1, 0.95; PC1, 0.99; PC2, 0.99; PC3, 0.97; PC4, 0.95; and PC5, 0.80. The accuracy obtained was as follows: CM1, 93.99%; JM1, 84.87%; KC1, 83.25%; KC2, 79.11%; KC3, 78.25%; KC4, 83.18%; MC1, 99.01%; MC2, 70.18%; MW1, 88.90%; PC1, 98.99%; PC2, 99.80%; PC3, 94.11%; PC4, 94.4%; and PC5, 79.02%. The proposed method results were compared with the result obtained from different methods. The proposed model obtained better results than other methods for data set CM1, KC4, MC1, PC1, PC2, PC3, PC4, and PC5.
Mass, velocity anisotropy, and pseudo phase-space density profiles of Abell 2142 (Corrigendum)

The pseudo phase-space density profile of Abell 2142, defined with the galaxy number density profile ν instead of the cluster mass density profile ρ, was shown in Fig. 12 of Munari et al. (2014). This graph was erroneous (because we had incorrectly considered the projected number density profile instead of the 3D profile). The correct figure is shown below. The values in Table 4 are changed, and the correct ones are reported in the table below. While Fig. 12 of Munari et al. (2014) indicated that the PPSDs computed with the number density profile are significantly shallower than the theoretical relation of Dehnen & McLaughlin (2005), the corrected version of the figure shown here indicates that the PPSDs computed with the number density profile are now either consistent with the relation of Dehnen & McLaughlin (Q(r) for BLUE sample) or only slightly shallower, but not less consistent with that relation than found for the PPSDs computed with the mass density profile. Therefore, the statement in Munari et al. (2014) that the mass density profile represents the PPSD and β − γ relations better is no longer correct. Indeed, Figs. 11 and 13 of Munari et al. show that the β − γ relations obtained using the mass density or tracer number density are indistinguishable for the RED and ALL samples. And therefore, the entire discussion of the greater relevance of the mass density profile relative to the galaxy number density profile must be dismissed. Fig. 12. Same as Fig. 10 of Munari et al. (2014), but now using the radial profiles of galaxy number density instead of total mass density to estimate the PPSD.
Shoulder Suppressing Technique for dual mode SAW resonators

A new type of RF filter which combines the excellent far out rejection of an LCR Filter with the sharp transition band of a Ladder Filter is introduced. The new structure, called SST for Shoulder Suppressing Technique, consists of a dual mode resonant cavity where the input and output of the resonator are electrically coupled via a small interdigital capacitor. Properly designed, electrical notches can be placed on both the low and high side of the pass band, sharpening the transition band and completely eliminating the hump on the high side of the pass band which is a characteristic of traditional LCR filters. We successfully designed SST-LCR filters with no characteristic high side hump. Designs for the cellular and K-PCS bands have been developed which have superior shape factors, 50 dB out of band rejections and insertion losses of 2.5 and 3.5 dB respectively.