Miracle-dz/UniFAR-FTUs huggingface dataset:
Prediksi Saham PT. Aneka Tambang Tbk. dengan K-Nearest Neighbors

Teknologi informasi yang semakin berkembang membuat data yang dihasilkan turut tumbuh menjadi big data. Data tersebut dapat dimanfaatkan dengan disimpan, dikumpulkan, dan ditambang sehingga menghasilkan informasi dan pengetahuan yang bernilai. Penambangan data merupakan proses menerapkan algoritma machine learning untuk mengekstraksi informasi dari data. Prediksi merupakan bentuk penambangan data untuk mendapatkan informasi di masa depan dari data sebelumnya. Prediksi saham PT Aneka Tambang dibutuhkan investor untuk mengurangi resiko finansial. Penelitian ini memodelkan prediksi saham PT Aneka Tambang menggunakan algoritma K-Nearest Neighbors. Data yang diolah berasal dari sumber terbuka dari tahun 2018 sampai 2021. Hasil prediksi membuktikan bahwa model saham PT Aneka Tambang optimal diperoleh pada perbandingan data training : testing sebesar 9:1, dengan nilai akurasi sebesar 93,36%.
On the Evaluation of the Collection Kernel for the Coalescence of Water Droplets

Abstract Two anomalies are described which arise in the kernel for stochastic droplet collection when it is specified by the formula of Scott and Chen for the linear collision efficiency y(R,r) and by the formula of Wobus et al. for the droplet terminal velocity V(R). It is pointed out that if accurate values for y(R,r) are to be obtained for a given droplet pair by interpolation using data for specific droplet pairs, then for large droplet radii (R<30 μm) it is desirable that these data he tabulated for 2-μm intervals of R. It is shown that if the difference in terminal velocities of two droplets is computed from a formula approximating V(R) and composed of various functions V*(R) applicable over adjoining domains of R, then it is necessary that these functions be constructed so that the formula and its derivatives, at least up to second order, are everywhere continuous. An improved formula for V(R) satisfying this criterion is described.
The pressure-dilatation correlation in compressible flows

Simulations of simple compressible flows have been performed to enable the direct estimation of the pressure–dilatation correlation. The generally accepted belief that this correlation may be important in high‐speed flows has been verified by the simulations. The pressure–dilatation correlation is theoretically investigated by considering the equation for fluctuating pressure in an arbitrary compressible flow. This leads to the isolation of a component of the pressure–dilatation that exhibits temporal oscillations on a fast time scale. Direct numerical simulations of homogeneous shear turbulence and isotropic turbulence show that this fast component has a negligible contribution to the evolution of turbulent kinetic energy. Then, an analysis for the case of homogeneous turbulence is performed to obtain a formal solution for the nonoscillatory pressure–dilatation. Simplifications lead to a model that algebraically relates the pressure–dilatation to quantities traditionally obtained in incompressible turbulence closures. The model is validated by direct comparison with the simulations.
Statistical performance analysis of the minimum-norm method

The authors analyze the performance of the minimum-norm method for estimating the direction of arrival (DOA) of plane waves in white noise in the case of a linear equispaced sensor array. They examine the perturbation in the roots of the polynomial formed in the intermediate step of the minimum-norm method. In particular, asymptotic results for the mean-squared error in the estimates of the direction of arrival are derived. Simple closed-form expressions are obtained for the one- and two-source case to get further insight. Computer simulation results that substantiate the analysis are provided and compared to those obtained for Root-MUSIC. It is shown that the relative performance of the two methods is directly dependent on the ratio of their parameter sensitivities. <<ETX>>
Accurate measurements of laser-induced bulk damage density

The laser damage community has long been searching for the reproducibility of damage measurements in the nanosecond (ns) regime. Here we show that laser-induced bulk damage density of frequency conversion crystals can be measured with high accuracy and repeatability in the range from 2 to 20 ns. The rasterscan test procedure (Lamaignère et al 2007 Rev. Sci. Instrum. 78 103105), previously developed in order to determine laser damage density of large aperture UV fused silica optics, has been adapted to bulk damage measurement. The large volume scanned during tests permits us to measure very low damage densities. For smaller optical components, small volumes are tested using the normalized 1/1 test procedure. Whatever test procedures, accuracy and repeatability are obtained by means of a suitable data reduction. For comparison between different procedures, the classical damage probability plot has to be converted in terms of damage density. The consideration of error bars on damage site distributions is compulsory to compare experimental data. A special emphasis is put on damage detection tools. When tests are carried out on diverse facilities, pulse duration, spatial distribution and beam overlap are the key parameters which are to be taken into account to compare experimental data. We describe the equipment, test procedures and data analysis to perform these damage tests with small beams (Gaussian beams, about 1 mm @1/e, and top-hat beams). Other tests are realized with larger beams (cm sized) which are compared with small beam results. The consistency of all the results gives confidence in the measurements. Reproducibility of measures is discussed in connection with current theoretical understanding of laser damage.
Larmor precession, a technique for high-sensitivity neutron diffraction

A method of carrying out high-precision measurements of crystal lattice parameters, at least an order of magnitude more sensitive than conventional neutron techniques using Larmor precession is presented. We show that the method can be used for absolute and relative measurements of the lattice constants and mosaicity and report some new results demonstrating the power of the method.
Combinatorial configurations of fibered polynomials

We study from a combinatorial point of view quadratic fibered polynomials. The main object of this paper is the construction of a combinatorial model of a subset of the parameter space. This set (the configuration space) is proved to be a Hausdorff compact and connected space. Then, we prove that an abstract configuration which is non-recurrent can be uniquely realized by a quadratic fibered polynomial.
Synthesis, Antioxidant, and Electrochemical Behavior Studies of 2-Amino-4H-Chromene Derivatives Catalyzed by WEOFPA: Green Protocol

Abstract In this work, we have described an efficient one-pot three-component preparation of 2-amino-4H-chromene by the reaction of aromatic aldehyde (1), malononitrile, or ethylcyanoacetate (2), and α or ꞵ-naphthol or resorcinol (3) in the presence of catalyst Water Extract of Orange Fruit Peel Ash agro-waste extracted solvent medium (4 mL) with few drops of ethanol as co-solvent accelerated by microwave irradiation. The reaction is optimized by various methods such as magnetic stirring, mechanochemical, ultrasound, and microwave irradiation, but the microwave irradiation in 180 W power gave excelled yield and faster rate product isolation (4–5 min). The method developed found eco-friendly, metal-free, chemical-less, and solvent-less, inexpensive, and facile approach for the synthesis of 2-amino-4H-chromene derivatives. The final product isolated recrystallized in ethanol, and characterized by FT-IR, 1H-, and 13C-NMR and LC-MS spectrometry techniques. Some of the selected chromene derivatives are subjected to antioxidant activity with concentration range 200–1,000 µg/µL by 2,2-diphenyl-1-picrylhydrazyl method. The derivatives 4a, 4 g, 4h, 6a, 6b, 6c, 8a, and 8f showed antioxidant activities and were comparable to standard ascorbic acid used. Further, studies on electrochemical behavior of selected chromene derivatives (4e, 4f, 4 g, 4i, 6c, 6f, 8d, and 8f) by cyclic voltammetry technique with 50 mVs−1, and revealed that, some of these molecules are good oxidation and reduction potential.
The cohesion of solid magnesium and calcium oxide: the role of in-crystal modification of the oxide ion and electron correlation

The cohesive properties of solid MgO and CaO are investigated using the fully ionic description calculating exactly, after generating the electronic wavefunctions of the ions, those portions of each inter-ionic potential energy function that do not arise from electron correlation. Three major new refinements are introduced. The modifications of each anion wavefunction that arise from the crystalline environment are described using two new methods in which the environmentally generated contribution to the potential energy acting on an anion electron is related to the cation electron density. These methods improve substantially on earlier models, shown to be inadequate for solid oxides, in which the environmental potential energy has the form of that generated by a spherical shell of charge. Density functional theory is used to evaluate the contribution of electron correlation to the oxide-ion rearrangement energy, that is the energy required to convert a free 0- ion to an in-crystal 02- ion. For any oxide, this correlation term varies appreciably with crystal geometry, as well as differing significantly between different oxides at their equilibrium geometries. The present models for the in-crystal environment of the oxide ion require a new way of deriving the parameters that govern the damping of the dispersive attractions between the ions, this damping originating from ion-wavefunction overlap being too large to neglect.
Compact tri-band bandpass filter based on quarter-wavelength resonators

In this work, a planar microstrip tri-band filter based on quarter-wavelength resonators is presented, which allows independent control of the positions of all three passbands. Furthermore, the topology of the filter provides five transmission zeros and thus results in a highly selective response in all passbands. A synthesis procedure of the filter is presented and used to design a tri-band filter which operates at WLAN frequencies of 2.4/3.5/5.2 GHz. The designed filter outperforms all other state-of-the-art tri-band filters in terms of compact size, high selectivity and transmission, and return-loss characteristics.
Machine vision-based real-time early flame and smoke detection

This paper proposes a novel real-time machine video-based flame and smoke detection method that can be incorporated with a surveillance system for early alerts. Automatic monitoring systems use the motion history detection algorithm to register the possible flame and smoke position in a video and then analyze the spectral, spatial and temporal characteristics of the flame and smoke regions in the image sequences. The spectral probability density is represented by comparing the flame and smoke color histogram model, where HSI color spaces are used. The spatial probability density is represented by computing the flame and smoke turbulent phenomena with the relation of perimeter and area. Statistical distribution of the spectral and spatial probability density is weighted with the fuzzy reasoning system to give the potential flame and smoke candidate region. The temporal probability density is represented by extracting the flickering area with level crossing and separating the alias objects from the flame and smoke region. Then, the continuously adaptive mean shift (CAMSHIFT) vision tracking algorithm is employed to provide feedback of the flame and smoke real-time position at a high frame rate. Experimental results under a variety of conditions show that the proposed method is capable of detecting flame and smoke reliably.
The theory of radiatively driven stellar winds. II - The line acceleration

Numerical values of the radiation pressure on spectral lines are presented for the envelopes of stars with type O--G, and with any luminosity, metallicity, or velocity structure. The line acceleration was calculated using a tabulation of atomic lines that is complete for the elements H--Zn. The line acceleration is remarkably constant over the temperature range 50,000> or =T/sub eff/> or =10,000 K, but drops off sharply for cooler stars. The anomalous ionization observed in OB stars decreases the acceleration by up to a factor of 2 from radiative equilibrium values. More than one-half of the acceleration comes from lines whose frequencies overlap with those of neighboring lines at some point in the wind. Line blanketing of the continuum flux by the wind becomes significant for mass loss rates exceeding approx.10/sup -6/ M/sub sun/ yr/sup -1/. The predicted and observed mass loss rates are in complete agreement for the OB stars, and we conclude that radiation pressure is the dominant mechanism driving the winds from these stars. The mass loss rates of Wolf-Rayet stars are not explained by these models, even accounting for the effects of chemical enrichment on the line acceleration. Radiation-driven mass loss is still significant in F andmore » G supergiants, but the predicted rates are smaller than for OBA supergiants of comparable luminosity. The predicted mass loss rate scales nearly linearly with metallicity, with obvious consequences for stellar systems formed in regions of very high, or very low, metallicity. Subject headings: stars: early-type: stars: mass loss: stars: supergiants: stars: winds: stars: Wolf-Rayet« less
DC SQUID series array amplifiers with 120 MHz bandwidth

We report on the performance of dc SQUID (Superconducting Quantum Interference Device) series array amplifiers from dc to 500 MHz. The arrays consist of up to 100 dc SQUIDs, with varying degrees of intracoil damping; the flux focusing washer of each SQUID is electrically isolated from the SQUID loop (L/sub sq/=18 pH). Using an rf network analyzer, we have observed high-frequency resonances in the response at bias points corresponding to distortions in the dc transfer functions. Increasing distance between SQUIDs in the array reduces the distortions. Distortions are also more pronounced, and bandwidth reduced, in devices incorporating the flux-focusing washer into the SQUID body. With intracoil damping of 0.25 /spl Omega/ per turn on the input coil, the voltage-flux transfer characteristics of the isolated-washer design and 300 /spl mu/m center-to-center SQUID spacing are free of significant distortions, and the bandwidth is not degraded compared to undamped devices. The 100-SQUID array has 150 nH input inductance, 500 V/A transimpedance, 2.5 pA/ Hz equivalent input current noise at 4 K, and 120 MHz bandwidth.
Note on the complete scheme of electrodynamic equations of a moving material medium, and on electrostriction

This note forms a supplement to my third memoir on the “Dynamic Theory of the Æther,” to the sections of which the references made. It is intended in the first place to express with full generality electrodynamic equations of a material medium moving in any manner, thus completing the scheme which has been already developed subject to simplifying restrictions in the memoirs referred to obtain a definite and consistent theoretical basis it was necessary contemplate the material system as made up of discrete molecules, involving in their constitutions orbital systems of electrons, and having through the practically stagnant æther.
Theory of passively mode-locked lasers for the case of a nonlinear complex-propagation coefficient

We examine passive mode locking, to which not only net-gain saturation but also group-velocity dispersion and self-phase modulation contribute significantly. Different sources of self-phase modulation are considered, and closed-form analytical solutions are obtained. The case of the colliding-pulse mode locking is discussed, and an ideal case is considered, in which the self-phase modulation and group-velocity dispersion are balanced so as to take maximum advantage of this additional shaping mechanism. This mechanism is shown to be similar to that which causes solitons in optical fibers; it provides additional reduction of the pulse width and significantly improves the stability against fluctuations in net gain.
Katabatic flow : Analytic solution for gradually varying eddy diffusivities

Abstract A simple form of the Prandtl model addressing pure katabatic flows is solved. The new analytic solution is valid for almost any assigned eddy diffusivity K(z) and constant Prandtl number. This model assumes a one-dimensional steady state for momentum and heat balance. Its approximate solution, obtained using the WKB method, appears as a generalization and improvement of the classic analytic solution for the constant-K case. It is compared favorably against a numerical solution. A comparison with observations from PASTEX, Austria 1994, shows that the new solution is much closer to the data than the constant-K solution. The dynamics revealed with this new solution is discussed (relatively sharper near-surface profiles, their gradients, and the low-level jet), and a suggestion toward improving boundary layer parameterizations is offered.
Dynamic maintenance of geometric structures made easy

The problem of dynamically maintaining geometric structures is considered. A technique is proposed that uses randomized incremental algorithms which are augmented to allow deletions of objects. A model for distributions on the possible input sequences of insertions and deletions is developed and analyzed using R. Seidel's backwards analysis. It is further shown how to apply this to maintain Voronoi diagrams, convex hulls, and planar subdivisions. A strikingly simple algorithm for the maintenance of convex hulls in any dimension is given. The expected running time is determined. <<ETX>>
Impact of Geographic-Dependent Parameter Optimization on Climate Estimation and Prediction: Simulation with an Intermediate Coupled Model

AbstractBecause of the geographic dependence of model sensitivities and observing systems, allowing optimized parameter values to vary geographically may significantly enhance the signal in parameter estimation. Using an intermediate atmosphere–ocean–land coupled model, the impact of geographic dependence of model sensitivities on parameter optimization is explored within a twin-experiment framework. The coupled model consists of a 1-layer global barotropic atmosphere model, a 1.5-layer baroclinic ocean including a slab mixed layer with simulated upwelling by a streamfunction equation, and a simple land model. The assimilation model is biased by erroneously setting the values of all model parameters. The four most sensitive parameters identified by sensitivity studies are used to perform traditional single-value parameter estimation and new geographic-dependent parameter optimization. Results show that the new parameter optimization significantly improves the quality of state estimates compared to the tra.
Detection Mechanism of Spontaneous Polarization in Ferroelectric Thin Films Using Electrostatic Force Microscopy

Mechanism on the detection of spontaneous polarization in a Pb(Zr0.5Ti0.5)O3 (PZT) film using contact mode of electrostatic force microscopy (EFM) is investigated. Theoretical calculations are performed on deflections induced by electrostatic force (uωe) between the tip and the sample and electromechanical vibrations (uωp) of the ferroelectric materials, respectively. From the calculation, uωe and uωp are 3.73×10-9 and 1.77×10-13 m. Enhanced mode of EFM shows the complete cancellation of the EFM image induced by the electrostatic force between the tip and the film through controlling dc voltage. Hence, electrostatic force effect is a main contributor on the detection mechanism of spontaneous polarization using EFM in contact mode.
A radial in-plane DSPI interferometer using diffractive optics for residual stresses measurement

This paper presents a new configuration of a digital speckle pattern interferometer that uses a binary diffractive optical element (DOE) to achieve radial in-plane sensitivity. The use of the DOE ensures constant sensitivity to the interferometer since it only depends on the grating period and does not depend on the wavelength of the illumination source. The paper describes the principles as well as the concepts of a portable device that was integrated to a drilling module to apply the hole drilling method for residual stresses measurement. Comparative results showed that the combined system can measure residual stress fields with uncertainty comparable with the classical strain gage based hole drilling method, but at least four times faster. A practical application of residual stresses measurement outside the laboratory is briefly presented.
Patched grid and adaptive mesh refinement strategies for the calculation of the transport of vortices

This paper presents two techniques allowing local grid refinement to calculate the transport of vortices. one is the patched grid (PG) method which allows non‐coincident interfaces between blocks. Treatment of the non‐coincident interfaces is given in detail. The second one is the adaptive mesh refinement (AMR) method which has been developed in order to create embedded sub‐grids. The efficiency of these two methods is demonstrated by some validating tests. Then the PG and AMR strategies are applied in the computation of the transport of vortices. We start with a simple vortex flow in a cubic box. Then, the flowfield around a complex aircraft configuration is calculated using the two refinement techniques. Results are compared with a fine, referenced grid calculation. Copyright © 2002 John Wiley & Sons, Ltd.
Minimal curves in six dimensions

Classical strings and minimal surfaces in a flat spacetime correspond to pairs of 'minimal' (i.e. null) curves in its complexification. The authors show how to find null curves in dimension six by use of twistor methods. The twistor space for C6 is the space of pure spinors for C8. They review the geometry of this space and establish a correspondence between 'pure' curves in twistor space and null ruled 2-surfaces in C6. This correspondence generates an explicit parameterisation of null curves in C6, thereby generalising the Weierstrass-Eisenhart parametrisation of null curves in C3 or C4. They also describe covariant methods for finding the periodic real null curves for string theory in real 6-space of any signature.
Computational Methods for Inverse Problems

In verse problems arise in a number of important practical applications, ranging from biomedical imaging to seismic prospecting. This book provides the reader with a basic understanding of both the underlying mathematics and the computational methods used to solve inverse problems. It also addresses specialized topics like image reconstruction, parameter identification, total variation methods, nonnegativity constraints, and regularization parameter selection methods. Because inverse problems typically involve the estimation of certain quantities based on indirect measurements, the estimation process is often ill-posed. Regularization methods, which have been developed to deal with this ill-posedness, are carefully explained in the early chapters of Computational Methods for Inverse Problems. The book also integrates mathematical and statistical theory with applications and practical computational methods, including topics like maximum likelihood estimation and Bayesian estimation. Several web-based resources are available to make this monograph interactive, including a collection of MATLAB m-files used to generate many of the examples and figures.