Miracle-dz/UniFAR-FTUs huggingface dataset:
How to handle missing data in regression models using information criteria *

An important application of multiple regression is predictor selection. When there are no missing values in the data, information criteria can be used to select predictors. For example, one could apply the small‐sample‐size corrected version of the Akaike information criterion (AIC), the (AICC). In this article, we discuss how information criteria should be calculated when the dependent variable and/or the predictors contain missing values. Therewith, we extensively discuss and evaluate three models that can be employed to deal with the missing data, that is, to predict the missing values. The most complex model, that is, the model with all available predictors, outperforms the other models. These results also apply to more general hypotheses than predictor selection and also to structural equation modeling (SEM) models.
High‐brightness terahertz beams characterized with an ultrafast detector

We have significantly improved the emission and detection of electromagnetic beams of single‐cycle 0.5 THz pulses, through the use of new dipolar antenna structures. The frequency response was extended to well beyond 1 THz, and the beam power was increased by more than 15 times. The antennas were located at the foci of sapphire lenses and were photoconductively driven by ultrafast laser pulses. An additional collimation by a paraboloidal mirror produced a beam with a 25 mrad divergence, and subsequent focusing by a second identical mirror improved the coupling between the transmitting and receiving antenna by orders of magnitude.
A pragmatic risk-based approach to prioritizing bridges

The objective of this paper is to present a 'straw-person' framework that appears to be a practical first step towards a more transparent, objective, quantitative and risk-based approach to bridge assessment and prioritization. While the framework presented is qualitative in nature it has distinct advantages over the current approach in that (a) it explicitly recognizes key performance limit states, (b) directly addresses bridge hazards, vulnerabilities, and exposures, (c) incorporates the uncertainty associated with various assessment techniques and provides flexibility for their implementation, and (d) provides a means to capture (in a useable format) expert knowledge and heuristics from top bridge engineers. In addition to the straw-person framework, the paper presents a rudimentary classification system to illustrate one approach to implementation. A series of case studies are then presented to demonstrate the potential value of this approach in distinguishing between bridges that are essentially "equivalent" based on the current assessment procedure. In addition, these case studies also serve to illustrate that the proposed approach may be utilized with existing inspection data. The paper concludes with some observations and comments regarding the straw-person framework presented.
Quad-SDK: Full Stack Software Framework for Agile Quadrupedal Locomotion

—This work presents Quad-SDK, an open source ROS-based full stack software framework for agile quadrupedal locomotion. The design of Quad-SDK is focused on the vertical integration of planning, control, estimation, communication, and development tools which enable agile quadrupedal loco-motion in simulation and hardware with minimal user changes for multiple platforms. Furthermore, the modular software architecture allows researchers to experiment with their own implementations of different components while leveraging the existing framework. Quad-SDK also offers Gazebo simulation support and a suite of visualization and data-processing tools for rapid development. This work presents the high-level architecture of the software, its core features, and demonstrations of the agile locomotion it enables.
rf amplification in a three-terminal magnetic tunnel junction with a magnetic vortex structure

We fabricated a three-terminal MgO-based magnetic tunnel junction including a free layer for use as a vortex-type spin structure. The resonant motion of the magnetic vortex core, excited by the application of rf current to the free layer, was successfully detected through the tunneling magnetoresistance effect using a homodyne detection technique. By analyzing the detected dc signal, we were able to qualitatively estimate the efficiency of the spin-transfer induced excitation. From the parameters obtained in the experiment, we found that substantial voltage gain can be realized with this device.
On the Transonic-Dip Mechanism of Flutter of a Sweptback Wing

'Goldstein, S. , "On Laminar Boundary Layer Flow Near a Position of Separation," Quarterly Journal of Mechanics and Applied Mathematics, Vol. 1, Feb. 1948, p. 43. Moore, F. K. , "On the Separation of the Unsteady Laminar Boundary Layer," Grenzschichtforschung, edited by H. Gortler, Springer, Heidelberg, 1957, p. 296. 3 Rott, N. , "Unsteady Viseous Flow in the Vicinity of a Stagnation Point," Quarterly of Applied Mathematics, Vol. 13, Jan. 1956, p. 444. Sears, W. R. , "Some Recent Developments in Aerofoil Theory," Journal of the Aerospace Sciences, Vol. 23, May 1956, p. 490. Brown, S. N. and Stewartson, K. , "Laminar Separation," Annual Review of Fluid Mechanics, Vol. 1, 1969, p. 45. Williams, J. C. , "Incompressible Boundary-Layer Separation," Annual Review of Fluid Mechanics, Vol. 9, 1977, p. 113. Riley, N. J., "Unsteady Laminar Boundary Layers," S/AM Review, Vol. 17, April 1975, p. 274. Telionis, D. P. and Tsahalis, D. Th. , "The Response of Unsteady Boundary-Layer Separation to Impulsive Changes of Outer Flow," AIAA Journal, Vol. 12, May 1974, p. 614. Bradshaw, P., "Prediction of Separation Using Boundary-Layer Theory," AGARD Lecture Series'94, 1978, p. 11-1. Bodonyi, R. J. and Stewartson, K. , "The Unsteady Laminar Boundary Layer on a Rotating Disk in a Counter-Rotating Fluid," Journal of Fluid Mechanics, Vol. 79, March 1977, p. 669. 11 Stewartson, K. , "Is the Singularity at Separation Removable? " Journal of Fluid Mechanics, Vol. 44, Nov. 1970, p. 347. Cebeci, T. and Bradshaw, P., Momentum Transfer in Boundary Layers, McGraw Hill/Hemisphere, Washington, 1977. Carter, J., "A New Boundary Layer Interaction Technique for Separated Flows," NASATM 78690, 1978. 1 Will iams, J. C. and Johnson, W. D. , "Semi-Similar Solutions to Unsteady Boundary Layer Flows including Separation," AIAA Journal, Vol. 12, Oct. 1974, p. 1388. l Cebeci, T. , "An Unsteady Laminar Boundary Layer with Separation and Reattachment," AIAA Journal, Vol. 16, Dec. 1978, p. 1305. L M
Towards a comprehensive computational model for the respiratory system

This paper is concerned with computational modeling of the respiratory system against the background of acute lung diseases and mechanical ventilation. Conceptually, we divide the lung into two major subsystems, namely the conducting airways and the respiratory zone represented by lung parenchyma. Owing to their respective complexity, both parts are themselves out of range for a direct numerical simulation resolving all relevant length scales. Therefore, we develop detailed individual models for parts of the subsystems as a basis for novel multi‐scale approaches taking into account the unresolved parts appropriately. In the tracheobronchial region, CT‐based geometries up to a maximum of approximately seven generations are employed in fluid–structure interaction simulations, considering not only airway wall deformability but also the influence of surrounding lung tissue. Physiological outflow boundary conditions are derived by considering the impedance of the unresolved parts of the lung in a fully coupled 3D‐1D approach. In the respiratory zone, an ensemble of alveoli representing a single ventilatory unit is modeled considering not only soft tissue behavior but also the influence of the covering surfactant film. Novel nested multi‐scale procedures are then employed to simulate the dynamic behavior of lung parenchyma as a whole and local alveolar ensembles simultaneously without resolving the alveolar micro‐structure completely. Copyright © 2010 John Wiley & Sons, Ltd.
Trapping artifacts in quasi-steady-state photoluminescence and photoconductance lifetime measurements on silicon wafers

Photoluminescence and photoconductance lifetime measurements on multicrystalline silicon wafers are presented. It is demonstrated experimentally that the large overestimation of the lifetime at low carrier concentrations due to trapping that is observed in photoconductance measurements is not found in photoluminescence data. This is explained theoretically by the dependence of photoluminescence and photoconductance on the product and the sum, respectively, of the minority and majority carrier densities. Based on this analysis, it is shown that photoluminescence lifetime measurements are not significantly affected by minority carrier trapping in most practical cases while implied current-voltage curves obtained from photoluminescence are completely unaffected.
Highly polarized absorption and photoluminescence of stretch-aligned single-wall carbon nanotubes dispersed in gelatin films

Substantial alignment of isolated individual single-wall carbon nanotubes (SWNTs) has been achieved by mechanically stretching gelatin films filled with homogeneously dispersed SWNTs. Highly polarized absorption and photoluminescence are observed that are attributed to interband optical transitions in SWNTs. Sharp and well-resolved spectral peaks comparable to those for an SWNT micelle suspension confirm good isolation of the tubes in dried films. Gelatin’s remarkable features such as miscibility with SWNT micelles, protective colloid, film-forming ability, and stretchability play important roles in the success. The realization of highly aligned and luminescent SWNT thin films should contribute to the development of SWNTs as novel optoelectronic materials.
concentration: a study of stage one

Heuristic concentration (HC) is a metaheuristic for the solution of certain combinatorial problems. In stage one, a concentration set (CS), consisting of nodes likely to be in the optimal solu-tion, is developed by multiple runs of an interchange heuristic. In stage two, a good, usually optimal, solution is constructed by selecting the best nodes from the CS. The CS is effective when it is small but comprehensive. Both of these characteristics depend upon: (1) the robustness of the heuristic; (2) the number of times it is run, q ; and (3) the number of ‘best’ solutions used to create the CS, m . Stage two is thus totally dependent upon the efficiency of stage one for the improved, and at least potentially optimal, solution. Proper values for the parameters m and q increase the probability of selecting correct elements to construct the optimal solution in stage two and to decrease the work in its identification. After a consideration of the robustness of two alternative interchange heuristics I will concentrate on the appropriate values for the parameters m and q . This is an empirical examination and the p -median problem is used throughout.
Dusty disks around young stars

Stars are formed through the collapse of giant molecular clouds. During this contraction the matter spins up and naturally forms a circumstellar disk. Once accretion comes to a halt, these disks are relatively stable. Some disks are known to last up to 10 Myrs. Most disks however, dissipate on shorter time scales under the influence of photoevaporation and planet formation. These disks, consisting of 99% gas and 1% dust, have revealed a high variety of dust composition and geometry. It is not clear what determines this variety and if higher mass stars also display this variety. In this thesis we analyzed a large sample of young stars, covering a mass range of ~2 to ~20 solar masses. Mid infrared imaging and spectroscopy have been obtained, to determine their composition and geometry. The results were placed in a multi-wavelength context as provided by the literature and a survey for any possible trends was carried out. In addition, case studies were performed of two special stars. Comprehensive data sets were gathered and a radiative transfer code was used to create detailed models of their disk geometry.
Validation of microwave vegetation indices using field experiment data sets

A recent study established the theoretical basis for a new type of index based on passive microwave vegetation indices (MVIs). The approach was then calibrated for use with data from the Advanced Microwave Scanning Radiometer (AMSR-E) on the Aqua satellite under the assumption that there is no significant polarization dependence of the vegetation emission and attenuation properties. To demonstrate the potential of the new microwave vegetation indices, these were compared with the Normalized Difference of Vegetation Index (NDVI) derived using MODIS at continental and global scales. These results verified that the microwave vegetation indices can provide new and complementary information on vegetation to NDVI for the global monitoring of vegetation and ecosystem properties from space. The next phase of analysis has focused on quantifiable vegetation parameters, specifically vegetation water content that is a valuable parameter in soil moisture retrievals using microwave data. Data sets collected in several recent large scale field campaigns included vegetation water content over domains in addition to conventional indices. Comparisons to date indicate that the MVI does provide vegetation water content information, however, further analysis of vegetation type effects are needed.
Array converter of infrared images into visible images, based on waveguide microcavities

This paper proposes a new method of converting IR images into the visible region of the spectrum of electromagnetic waves, using waveguide cavity structures of micrometer size as sensitive elements. The method is based on modulation of the intrinsic equidistant spectrum of the cavity under the external action of electromagnetic radiation in the IR region by varying the optical properties of the material from which the sensitive element is made. The structure and the operating principles of the IR-to-visible image converter is discussed on the basis of an array of waveguide ring microcavities. It is shown that the sensitivity of such a converter to variation of the IR radiation power can reach 2.6×10−12W.
Self-similar concentration profiles in buoyant mixing of miscible fluids in a vertical tube

The influence of the density contrast (characterized by the Atwood number At) on gravity-induced mixing between two miscible fluids in a long vertical tube has been studied experimentally. Cross-section averaged fluid concentration profiles along the tube are measured optically: for large enough At values, they display a self-similar dependence in a broad range of times and distances and verify a diffusion law with an effective diffusivity 105 times higher than for molecular diffusion. At lower At values, this diffusive domain is limited by a sharp front moving at a velocity increasing with At. Below a threshold At value the diffusive behavior disappears.
Impulsive Stabilization for Control and Synchronization of Complex Networks with Coupling Delays

In the paper, synchronization of a class of complex dynamical networks with time-varying coupling delays is considered. By establishing impulsive delay differential inequalities, sufficient conditions on the asymptotical stability of complex dynamical networks are derived. Based on the analysis, two impulsive controllers are explicitly designed not only to achieve asymptotically stable for the complex networks, but also to ensure the convergence rate of complex networks. At last, some numerical examples are also given to illustrate the effectiveness of the proposed methods.
The impossibility of desuspending collapses

I t is known that in order to prove the polyhedral Schoenflies conjecture in all dimensions, it is enough to show that» if (B, B) is a (4, 3) ball pair, then B collapses (polyhedrally) to B. Recently, using the solution to the polyhedral Poincaré conjecture in high dimensions, Husch has shown [3] that if (B, B) is a (7, 6) ball pair, then B collapses to B. I t is tempting to try to prove that B* collapses to B by invoking the following conjecture. CONJECTURE A. If M is a polyhedral manifold, L a submanifold of M and S(M)\S(L)r then M\L. (S(X) denotes the suspension of X and " \ " denotes a polyhedral collapse. ) If Conjecture A were true we could suspend a (4, 3) ball pair three times to obtain a (7, 6) ball pair, use Husch's result, and then apply Conjecture A three times in order to desuspend the collapse. In this note we present a counterexample to Conjecture A, and discuss other conjectures related to the problem of desuspending collapses.
The evolution of faint radio sources

In a previous paper, we presented spectroscopic observations of a complete sample of identifications for faint radio sources [S(1.4 GHz) ≥ 0,1 mJy] and have shown that the majority of the objects are actively star-forming spirals. Here we derive the luminosity functions for elliptical and spiral galaxies in the sample, and show that the spiral galaxies are indistinguishable from the starburst galaxy population which dominates the counts at 60 μm. We show by testing a range of different evolutionary assumptions that the faint radio source counts can best be understood as due to the starburst population undergoing strong luminosity evolution, at a rate similar to that found for radio galaxies and optical quasars
Principal Component Pursuit with Weighted Nuclear Norm

Principal Component Pursuit (PCP) recovers low-dimensional structures from a small set of linear measurements, such as low rank matrix and sparse matrix. Pervious works mainly focus on exact recovery without additional noise. However, in many applications the observed measurements are corrupted by an additional white Gaussian noise (AWGN). In this paper, we model the recovered matrix the sum a low-rank matrix, a sparse matrix and an AWGN. We propose a weighted PCP for the recovery matrix, which is solved by alternating direction method. Numerical results show that the reconstructions performance of weighted PCP outperforms the classical PCP in term of accuracy.
On semi-infinite minmax programming with generalized invexity

Here, we consider the minmax programming problem with a set of restrictions indexed in a compact. As a novelty, we obtain optimality criteria of the Kuhn--Tucker type involving a limited number of restrictions and prove both necessity and sufficiency under new weaker invexity assumptions. Also some dual problems are introduced and it is proved that the weak and strong duality properties hold within the same environment.
Combining machine‐learning and molecular‐modeling methods for drug‐target affinity predictions

Machine learning (ML) techniques offer a novel and exciting approach in the drug discovery field. One might even argue that their current expansion may push traditional MM modeling techniques to a secondary role in modeling methods. In this review article, we advocate that a combination of both techniques could be the most efficient implementation in the coming years. Focusing on drug‐target affinity predictions, we first review pure ML approaches. Then, we introduced recent developments in mixing ML and MM methods in a single combined manner. Finally, we show the detailed implementation of a real industrial prospective study where nanomolar hits, on a kinase target, were obtained by combination of state of the art Monte Carlo MM simulations (PELE) with a ML ranking function.
Model Prediksi Kadar Air Media Tanam Menggunakan Regresi Linear Berganda (Studi Kasus Kebun Tomat Beef di Serenity Farm Mitra Habibi Garden)

Permintaan yang cukup tinggi akan tomat beef kepada Serenity Farm sebagai salah satu produsen tomat beef di daerah Lembang, Kabupaten Bandung masih belum sepenuhnya terpenuhi. Salah satu penyebab hal tersebut adalah kurang optimalnya pengelolaan kadar air pada media tanam yang digunakan. Kadar air media tanam yang stabil dapat mencegah penguapan air berlebih dari permukaan tanah, serta mencegah tanaman mengalami stres. Selain itu, kadar air media tanam dipengaruhi oleh iklim, spesifikasi tanaman dan media tanam itu sendiri, sehingga cukup sulit diprediksi. Kadar air media tanam dapat mencapai titik kritis bila telat melakukan penyiraman dan menyebabkan kelayuan permanen tanaman. Penelitian ini bertujuan untuk mengembangkan model prediksi kadar air media tanam budidaya tomat beef di greenhouse Serenity Farm menggunakan machine learning. Model prediksi kadar air ini dikembangkan untuk mencegah tanaman mengalami kekeringan, dengan membantu petani dalam pengambilan keputusan penyiraman. Algoritma pembelajaran yang digunakan adalah regresi linear berganda dengan variabel bebas yang terdiri dari data Hari Setelah Tanam (HST), jumlah penggunaan air penyiraman (mL/3 jam), suhu media tanam (oC/3 jam), dan kadar air media tanam (%/3 jam) 3 jam sebelumnya. Sedangkan nilai prediksi kadar air media tanam (%/3 jam) 3 jam berikutnya dijadikan variabel terikat. Model yang dibuat telah diuji dan divalidasi dengan tingkat akurasi masing-masing 83,80% dan 72,02%. Hasil tersebut menunjukkan bahwa model prediksi yang dikembangkan dapat diterapkan dalam memprediksi kadar air media tanam tomat beef di Serenity Farm.
Resolution of coherent and incoherent imaging systems reconsidered - Classical criteria and a statistical alternative

The resolution of coherent and incoherent imaging systems is usually evaluated in terms of classical resolution criteria, such as Rayleigh’s. Based on these criteria, incoherent imaging is generally concluded to be ‘better’ than coherent imaging. However, this paper reveals some misconceptions in the application of the classical criteria, which may lead to wrong conclusions. Furthermore, it is shown that classical resolution criteria are no longer appropriate if images are interpreted quantitatively instead of qualitatively. Then one needs an alternative criterion to compare coherent and incoherent imaging systems objectively. Such a criterion, which relates resolution to statistical measurement precision, is proposed in this paper. It is applied in the field of electron microscopy, where the question whether coherent high resolution transmission electron microscopy (HRTEM) or incoherent annular dark field scanning transmission electron microscopy (ADF STEM) is preferable has been an issue of considerable debate.
Dynamic Characteristics of Flow Separation From a Low Reynolds Number Airfoil

This study examines the generation of large scale vortices caused by flow separation from a flat wing at various angles of attack. Time-resolved particle image velocimetry is used to determine the evolution and convective characteristics of the large scale structures. A rectangular airfoil with aspect ratio of 0.5 is used and data are collected at a Reynolds number of 23,500, for angles of attack from 0° to 20°. Data consists of two dimensional velocity fields obtained at 500 Hz located at the airfoil centerline. The region of interest is near the separation point but fields of view extend over approximately one half of the chord length from the leading edge to document the downstream progression of the large scale vortical flow elements. The velocity data were processed to identify the vorticity field dynamics in terms of the Kelvin-Helmholtz instability occurring near the leading edge. The vortical structures are identified using vortex detection based on local circulation. The convective nature of the vortex elements are shown to consist of merging, stalling and convecting, with convective velocities on the order of 20% of the freestream velocity with an associated Stouhal number based on chord length and freestream velocity of approximately 1.0. Copyright © 2007 by ASME