Miracle-dz/UniFAR-FTUs huggingface dataset:
CLUSTERING EFFECT OF USER-OBJECT BIPARTITE NETWORK ON PERSONALIZED RECOMMENDATION

In this paper, the statistical property of the bipartite network, namely clustering coefficient C4 is taken into account and be embedded into the collaborative filtering (CF) algorithm to improve the algorithmic accuracy and diversity. In the improved CF algorithm, the user similarity is defined by the mass diffusion process, and we argue that the object clustering C4 of the bipartite network should be considered to improve the user similarity measurement. The statistical result shows that the clustering coefficient of the MovieLens data approximately has Poisson distribution. By considering the clustering effects of object nodes, the numerical simulation on a benchmark data set shows that the accuracy of the improved algorithm, measured by the average ranking score and precision, could be improved 15.3 and 13.0%, respectively, in the optimal case. In addition, numerical results show that the improved algorithm can provide more diverse recommendation results, for example, when the recommendation list contains 20 objects, the diversity, measured by the hamming distance, is improved by 28.7%. Since all of the real recommendation data are evolving with time, this work may shed some light on the adaptive recommendation algorithm according to the statistical properties of the user-object bipartite network.
The Ursa Minor dwarf galaxy : still an old stellar system.

We have constructed a color-magnitude diagram of the Ursa Minor dwarf spheroidal to m/sub V/ = 24.8 mag from charged-coupled device (CCD) observations with the Kitt Peak 4 m telescope. The main-sequence turnoff is easily visible. Fits to evolutionary isochrones and the globular M92 indicate that Ursa Minor has an age and metal abundance very similar to that of the latter cluster. No evidence for stars younger than about 16 billion years is seen, with the possible exception of approximately 20 stars believed to be blue stragglers. Ursa Minor is therefore an extreme-age galaxy, unlike superficially similar objects such as the Carina dwarf. Indeed, Ursa Minor may be the only outer-halo spheroidal whose stellar content lives up to the classical ideals of a Population II system. A distance modulus of (m-M)/sub 0/ = 19.0 mag is derived from a sliding fit to the M92 ridge lines. However, this modulus is uncertain by approx.0. 1 mag, for the horizontal branch in our color-magnitude diagram is poorly populated. The ratio of blue stragglers to anomalous Cepheids in Ursa Minor is estimated to be approx.100, a number that may provide an important constraint on binary models for the origin of these stars. A surprisingmore » result of our study is the discovery of clumpiness in the distribution of stars. This finding may give more weight to the idea that dwarf spheroidal galaxies were previously dwarf irregular galaxies, although clearly, if so, Ursa Minor must have lost its gaseous content very soon after formation. « less
Sensitivity Measure for Electric Power Load Dispatch Problem

Abstract This study performed sensitivity analysis of a multi-objective thermal power dispatch problem and explored a solution methodology exploiting the quality measure approach, which verifies that the non-inferior solutions are uniformly scattered in the objective space. The multi-objective thermal power dispatch problem having non-commensurable objectives, such as operating cost and minimal emissions, is undertaken to meet the systems' real and reactive power demands within generators' capacity constraints. Real and reactive power transmission line flows are obtained from generalized Z-bus distribution factors and are restricted within prescribed limits for the secure operation of a power system. A sensitivity measure is incorporated as a dispersion index to be minimized in order to investigate the effects of random variations in the model parameters of the optimal solution. A non-linear programming problem provides the framework for examining the objectives along with constraints in a weighted sum form of the multi-objective problem. The best objective weights are evaluated by conventional statistical measures, which characterize the correlation coefficients matrix evolution. A quality measure approach is exploited to compare the relative quality of a different set of non-inferior solutions before presenting it to the decision-maker for a final decision. The validity of the proposed method is demonstrated on a 30-bus IEEE power system.
Buried transverse‐junction stripe laser for optoelectronic‐integrated circuits

A buried transverse‐junction stripe (TJS) laser, a suitable laser diode for integration, has been fabricated using molecular‐beam epitaxial growth. The fundamental characteristics of the laser were as good as those of a conventional TJS laser. We have also demonstrated a fabrication process for the laser that is compatible with that for metal‐semiconductor field‐effect transistors (MESFETs) to be monolithically integrated. The characteristics of the MESFETs fabricated on substrates processed for the laser were the same as those fabricated on virgin substrates when such processed substrates were etched 2 μm deep.
Mixed Sky-Hook and ADD: Approaching the Filtering Limits of a Semi-Active Suspension

The problem considered in this paper is the design and analysis of control strategies for semiactive suspensions in road vehicles. The most commonly used control algorithm is the well-known sky-hook (SH) damping. Recently, a new control approach named acceleration driven damping (ADD) has been developed, using optimal-control theory. It has been shown that SH and ADD have complementary characteristics: SH provides large benefits around the body resonance; otherwise performs similarly to a passive suspension; instead, ADD provides large benefits beyond the body resonance. The first goal of this paper is to show that-in their specific frequency domains-SH and ADD provide quasi-optimal performances, namely, that it is impossible to achieve (with the same semi-active shock-absorber) better performances. This result has been obtained using the framework of the optimal predictive control, assuming full knowledge of the disturbance. This result is very interesting since it provides a lower-bound to semi-active suspension performances. The second goal of the paper is to develop a control algorithm which is able to mix the SH and ADD performances. This algorithm is surprisingly simple and provides quasi-optimal performances.
Frequency response of graphene phonons to heating and compression

The thermally softened and the mechanically stiffened graphene phonons have been formulated from the perspective of bond order-length-strength correlation with confirmation of the C–C bond length in the single-layer graphene contracting from 0.154 to 0.125 nm and the binding energy increasing from 0.65 to 1.04 eV. Matching theory to the measured temperature- and pressure-dependent Raman shift has derived that the Debye temperature drops from 2230 to 540 K, the atomic cohesive energy drops from 7.37 to 3.11 eV/atom, and the binding energy density increases from 250 to 320 eV/nm3 compared with the respective quantities of bulk diamond.
An Analog of the Adjugate Matrix for the Outer Inverse (2)

We investigate the determinantal representation by exploiting the limiting expression for the generalized inverse 𝐴(2)𝑇,𝑆. We show the equivalent relationship between the existence and limiting expression of 𝐴(2)𝑇,𝑆 and some limiting processes of matrices and deduce the new determinantal representations of 𝐴(2)𝑇,𝑆, based on some analog of the classical adjoint matrix. Using the analog of the classical adjoint matrix, we present Cramer rules for the restricted matrix equation 𝑆𝐴𝑋𝐵=𝐷,ℛ(𝑋)⊂𝑇,𝒩(𝑋)⊃.
Generalization of learning in pre‐lexical adjustments to word‐final devoicing.

Pre‐lexical representations of speech sounds have been to shown to change dynamically through a mechanism of lexically driven learning. [Norris et al. (2003). ] Here we investigated whether this type of learning occurs in native British English (BE) listeners for a word‐final stop contrast which is commonly de‐voiced in Dutch‐accented English. Specifically, this study asked whether the change in pre‐lexical representation also encodes information about the position of the critical sound within a word. After exposure to a native Dutch speaker’s productions of de‐voiced stops in word‐final position (but not in any other positions), BE listeners showed evidence of perceptual learning in a subsequent cross‐modal priming task, where auditory primes with voiceless final stops (e.g., [si:t], “seat”) facilitated recognition of visual targets with voiced final stops (e.g., “seed”). This learning generalized to test pairs where the critical contrast was in word‐initial position, e.g., auditory primes such as [taun] .
How Meaning of Life Correlates with Emptiness Syndrome of Minangkabau Elderly Women

The matrilineal culture in Minangkabau, West Sumatra, is a culture that is thick with emancipation values and the teachings of feminism. The matrilineal kinship system contains the importance of gender equality and justice, both philosophically and in terms of implementation. However, in reality, there has been a shift in the pattern of social responsibility towards women's parents who should have the position of bundo kanduang. The change in the way of social responsibility is marked by the number of parents being put into nursing homes. Psychological conditions related to emptiness syndrome and self-significance in elderly women need to be analyzed. This study involved 40 elderly women who live in social institutions in West Sumatra. This study concluded that there was a significant negative relationship (P value = 0.011) between the meaning of life and emptiness syndrome, which was a -0.396 Pearson correlation.
TFT-LCD Mura Defect Detection Using Wavelet and Cosine Transforms

Mura defects in LCM panel of TFT-LCD have the properties of local low contrast and luminance variation without a clear contour on a uniformly produced surface. This research proposes two methods which are discrete cosine transform (DCT) and discrete wavelet transform (DWT). These methods successfully detect simulated blob-mura and real mura defects. DWT method is based on symmetrical 9/7 tap Daubechies coefficients that is superior for filtering the regular structure of color filter and small area defects. DCT method is better for detecting luminance variation in large area and poor for small ones.
Precoding scheme based on constellation rotation for MISO systems

The error probability of a maximum-likelihood (ML) detector depends on the signal-to-noise ratio (SNR) and distances between each possible combined channel-transformed constellation (CCTC) point and its nearest neighbours. Among these distances, the minimum one dominates the bit-error rate (BER) performance. This paper proposes a precoder based on constellation rotation (CR) for multiple-input-single-output (MISO) systems armed with an ML detector, maximising the minimum distance according to the channel information optimally. With the proposed precoder, the BER performance of MISO systems is boosted remarkably in both quasistatic Rayleigh fading independent and correlated channels. Through systematic analysis, closed-form solutions of the optimal CR angle are derived for 2 × 1 MISO systems employing BPSK or QPSK. Simulation results demonstrate that there is performance improvement of at least 2 dB with the new 2 × 1 MISO system employing BPSK, and the improvement reaches at least 3dB when QPSK is employed. In addition, the new 2 × 1 MISO system outperforms the traditional one in correlated channels significantly.
Statistical inference on lattices

In many scientific disciplines, there is frequently a need to describe purely spatial interactions among objects located at the sites of a lattice. Of particular interest are the equilibrium states of physical and biological phenomena occurring simultaneously at sites in more than one dimension (for example, ferromagnetism, crystal formation, patterns of infection). Markov random fields form a wide class of intuitively appealing models for spatial interaction. Binary ones have been studied extensively in statistical mechanics where they are known as Ising models.
Model Based Damage Identification Using Output Spectral Densities

A damage identification method utilizing an existing computational model and output spectral densities is presented. The problem covered here is the detection, localization and quantification of damage in real vibrating elastomechanical structures. The damages are localized by means of changes in the dynamic characteristics between a reference model and the actual, measured system. The main contribution is that the exact measurement of the input signals is ignored. These signals are assumed to be an ergodic random process, whose statistical properties such as mean and covariances must be estimated. Power spectral densities allow random excitations to be dealt with. The lack of measurement information is treated by means of the dynamic condensation technique and the Kalman Bucy filter technique. In the first case the size of the model matrices are reduced to the number of measured degrees of freedom (dof). In the second procedure the measured responses are expanded to the size of the model matrices. With equally sized measurement and model matrices a linear equation system for the desired parameter changes is derived by using the sensitivity approach. The equation system for this inverse problem is usually ill-conditioned and must be regularized in some way. One possibility is to reduce the subset of parameters to be in error. The algorithm is applied to a beam structure and a measured laboratory structure, a multi story frame, in which artificial damage is introduced by weakening one column between two stories. So, it is shown that the location and the size of the corresponding stiffness decrease can be detected.
ASSESSING AND TESTING FOR THRESHOLD NONLINEARITY IN STOCK RETURNS

This paper proposes a test for threshold nonlinearity in a time series with generalized autore‐gressive conditional heteroscedasticity (GARCH) volatility dynamics. This test is used to examine whether financial returns on market indices exhibit asymmetric mean and volatility around a threshold value, using a double‐threshold GARCH model. The test adopts the reversible‐jump Markov chain Monte Carlo idea of Green, proposed in 1995, to calculate the posterior probabilities for a conventional GARCH model and a double‐threshold GARCH model. Posterior evidence favouring the threshold GARCH model indicates threshold nonlinearity with asymmetric behaviour of the mean and volatility. Simulation experiments demonstrate that the test works very well in distinguishing between the conventional GARCH and the double‐threshold GARCH models. In an application to eight international financial market indices, including the G‐7 countries, clear evidence supporting the hypothesis of threshold nonlinearity is discovered, simultaneously indicating an uneven mean‐reverting pattern and volatility asymmetry around a threshold return value.
MULTIFRACTAL DESCRIPTION OF SIMULATED FLOW VELOCITY IN IDEALISED POROUS MEDIA BY USING THE SANDBOX METHOD

The spatial description of flows in porous media is a main issue due to their influence on processes that take place inside. In addition to descriptive statistics, the multifractal analysis based on the Box-Counting fixed-size method has been used during last decade to study some porous media features. However, this method gives emphasis to domain regions containing few data points that spark the biased assessment of generalized fractal dimensions for negative moment orders. This circumstance is relevant when describing the flow velocity field in idealised three-dimensional porous media. The application of the Sandbox method is explored in this work as an alternative to the Box-Counting procedure for analyzing flow velocity magnitude simulated with the lattice model approach for six media with different porosities. According to the results, simulated flows have multiscaling behaviour. The multifractal spectra obtained with the Sandbox method reveal more heterogeneity as well as the presence of some extreme values in the distribution of high flow velocity magnitudes as porosity decreases. This situation is not so evident for the multifractal spectra estimated with the Box-Counting method. As a consequence, the description of the influence of porous media structure on flow velocity distribution provided by the Sandbox method improves the results obtained with the Box-Counting procedure.
Nonparametric Convergence Assessment for MCMC Model Selection

This article considers the problem of assessing the performance of MCMC model selection algorithms using a variety of nonparametric techniques. We consider a wide range of model selection problems to which MCMC model selection may be applied and propose several distance measures that can be used to quantify the similarity between multiple replications. These measures may be used to assess convergence by examining how “close” these replications of the chain are, since if all chains are at stationarity, then this distance should be small. Finally, we describe an alternative approach based upon the estimation of the convergence rate of the sub-Markov chain represented by the model indicators and finish by illustrating our approaches with several practical examples.
Semiconductor bridge: A plasma generator for the ignition of explosives

Small metal bridgewires are commonly used to ignite energetic powders such as pyrotechnics, propellants, and primary or secondary explosives. In this paper we describe a new means for igniting explosive materials using a semiconductor bridge (SCB). When driven with a short (20 μs), low‐energy pulse (less than 3.5 mJ), the SCB produces a hot plasma that ignites explosives. The SCB, a heavily n‐doped silicon film, typically 100 μm long by 380 μm wide by 2 μm thick, is 30 times smaller in volume than a conventional bridgewire. SCB devices produce a usable explosive output in a few tens of microseconds and operate at one‐tenth the input energy of metal bridgewires. In spite of the low energies for ignition, SCB devices are explosively safe. We describe SCB processing and experiments evaluating SCB operation. Also discussed are the SCB vaporization process, plasma formation, optical spectra from the discharge, heat transfer mechanisms from the SCB to the explosive powders, and SCB device applications.
Thickness effect on the microstructure, morphology and optoelectronic properties of ZnS films

Thin films of ZnS with thicknesses ranging from 100 to 600 nm have been deposited on glass substrates by close spaced thermal evaporation. All the films were grown at the same deposition conditions except the deposition time. The effect of thickness on the physical properties of ZnS films has been studied. The experimental results indicated that the thickness affects the structure, lattice strain, surface morphology and optoelectronic properties of ZnS films significantly. The films deposited at a thickness of 100 nm showed hexagonal structure whereas films of thickness 300 nm or more showed cubic structure. However, coexistence of both cubic and hexagonal structures was observed in the films of 200 nm thickness. The surface roughness of the films showed an increasing trend at higher thicknesses of the films. A blue-shift in the energy band gap along with an intense UV emission band was observed with the decrease of film thickness, which are ascribed to the quantum confinement effect. The behaviour of optical constants such as refractive index and extinction coefficient were analysed. The variation of refractive index and extinction coefficient with thickness was explained on the basis of the contribution from the packing density of the layers. The electrical resistivity as well as the activation energy were evaluated and found to decrease with the increase of film thickness. The thickness had a significant influence on the optical band gap as well as the luminescence intensity.
The H alpha Spectral Counterparts of Solar Hard X-Rays Microflares

Sensitive hard X-ray instrumentation has revealed energetically significant numbers of very small hard X-ray bursts, termed microflares by Lin et al. (1984). The H-alpha counterparts of several of these microflares were observed. The H-alpha counterparts are identified on the basis of their temporal coincidence with the observed hard X-ray bursts. They are very small in size and often appear in the vicinity of previous larger flares. The stronger microflares show red asymmetry in H-alpha, which corresponds to maximum downflows of approximately 75 km/s. 13 references.
Magnetic Ap Stars in the Hertzsprung-Russell Diagram

The evolutionary state of magnetic Ap stars is rediscussed using the recently released Hipparcos data. The distribution of the magnetic Ap stars of mass below 3 M☉ in the H-R diagram differs from that of the normal stars in the same temperature range at a high level of significance. Magnetic stars are concentrated toward the center of the main-sequence band. This is shown in two forms of the H-R diagram: one where log L is plotted against log Teff and a version more directly tied to the observed quantities, showing the astrometry-based luminosity (Arenou & Luri) against the (B2-G)0 index of Geneva photometry. In particular, it is found that magnetic fields appear only in stars that have already completed at least approximately 30% of their main-sequence lifetime. No clear picture emerges as to the possible evolution of the magnetic field across the main sequence. Hints of some (loose) relations between magnetic field strength and other stellar parameters are found: stars with shorter periods tend to have stronger fields, as do higher temperature and higher mass stars. A marginal trend of the magnetic flux to be lower in more slowly rotating stars may possibly be seen as suggesting a dynamo origin for the field. No correlation between the rotation period and the fraction of the main-sequence lifetime completed is observed, indicating that the slow rotation in these stars must already have been achieved before they became observably magnetic.
Thermally assisted resistive switching in Pr0.7Ca0.3MnO3/Ti/Ge2Sb2Te5 stack for nonvolatile memory applications

We propose a low power, high-performance nanoscale (φ = 150 nm) resistive memory device having a Ge2Sb2Te5/Ti/Pr0.7Ca0. 3MnO3 (GST/Ti/PCMO) structure. As a thermoelectric heater and/or thermal barrier, GST accelerates the Ti/PCMO interfacial redox process thermally by enhancing the mobility of oxygen ions and minimizes the loss of local heat. Improvement of the memory performances and voltage-time dilemma issue is achieved by adopting this type of thermally assisted process.
Temporal fusion for de-noising of RGB video received from small UAVs

Monitoring video data sources received from UAVs is especially challenging because of the quality of the video received. Due to the individual characteristics of the unmanned platform and the changing environment, the important elements in the scene are not always observable or easily identified. In addition to typical sensor noise, significant image degradation can occur during transmission of the video from an airborne platform. Interference from other transmitters, analog noise in the embedded avionics, and multi-path effects can corrupt the video signal during transmission, introducing distortion in the video received at the ground. In some cases, the loss of signal is so severe; no information is received in portions of an image frame. To improve the corrupt video, we capitalize on the oversampling in the temporal domain (across video frames), applying a data fusion approach to de-noise the video. The resulting video retains the significant scene content and dynamics, without distracting artifacts from noise. This allows humans to easily ingest the information from the video, and make it possible to utilize further video exploitation algorithms such as object detection and tracking.