nils-herrmann/clean_scirepeval huggingface dataset:
An Effort Toward Development of  $\hbox{MgB}_{2}$-Based Current Leads With 2000-A Rating

In this paper, we report an effort toward the development of general-purpose conduction-cooled current leads based on MgB2, which can carry 2000 A at 25 K. The leads have an overall length of 40 cm and a diameter of 5.8 mm, with Cu end caps with a length of 5 cm each for anchoring them to the superconducting system and the current source. Fe, Cu, and Ni are used as the barrier, the stabilizer, and the outer sheath materials, respectively. The critical parameters of the current leads, such as rated current Ic, thermal cycling stability, and heat leak, were tested and evaluated using a cryocooler-integrated cryostat test facility.
Effect of high energy electron irradiation on the electromechanical properties of poly (vinylidene fluoride-trifluorethylene) 50/50 and 65/35 copolymers

High energy electron irradiation with a broad range dosage was carried out on poly(vinylidene fluoride trifluorethylene) copolymer 65/35 mol% and 50/50 mol% films at different temperatures from room temperature to a temperature close to the melt temperature. The effect of irradiation on the properties of the films, such as electric field-induced strain, dielectric and polarisation behaviors, and mechanical modulus, is presented. The irradiated films can exhibit a very large electric field-induced strain, more than 4.5% longitudinal strain, and 3% transverse strain. The transverse strain of the stretched film can compare with the longitudinal strain; that of the unstretched film is much smaller than the longitudinal strain. With regard to the dielectric and polarization behaviors, we found that irradiation changes the copolymer from a typical ferroelectric to a relaxor ferroelectric in which the behavior of microregions under the electric field plays the key role. Between the two copolymers studied, we found that the 65/35 copolymer is preferred for both longitudinal and transverse strain generation. A model is proposed to explain the experimental results that the amplitude of the charge electrostrictive coefficient (Q) increases with decreasing crystallinity.
Electromagnetic properties of periodic cavities coupled to a radiating antenna

The electromagnetic properties of spatially periodic cavities determines both the linear and nonlinear interaction between the waves and the electron beam in high-power backward-wave oscillators. A corrugated cavity is usually left open at one end for extraction of the useful microwave energy; however, reflections at the open end are large so that a cavity is still formed. In contrast to a previously studied N period closed cavity where the number of axial modes with frequencies falling in the lowest pass band of the structure is equal to N+1, an open cavity was found to support only N axial modes. In this paper the resonance frequencies, quality factors and the field patterns of the axial modes in an open cavity were all investigated experimentally and the results are in very good agreement with those obtained using a new, time-dependent, quasi-three dimensional code. It was also demonstrated that a short interface section between the periodic cavity and the radiating antenna can drastically reduce the quality factors to the diffraction limit over a very wide frequency band. This is expected to substantially increase the starting current and allow operation at high-beam current without degradation of spectral purity.
Comparison of Peak Armature and Field Winding Currents for Different Topologies of 10-MW Superconducting Generators Under Short-Circuit Conditions

This paper studies the peak armature and peak field winding currents for three different topologies of 10 MW partial high temperature superconducting generators (HTSGs) under short-circuit conditions (SCC) by simulation. The investigated partial HTSGs employ copper armature windings and superconducting field windings with different armature and rotor topologies, i.e., iron-cored armature and rotor, air-cored armature and rotor, and iron-cored armature and air-cored rotor. For each HTSG topology, the investigation includes: 1) the field winding current control strategies; 2) the influence of operating field current; and 3) the ratings of circuit breakers for limiting the peak armature and peak field winding currents. The results can provide guidelines for determining the peak armature and peak field currents of HTSGs and also the possibility of limiting them by employing circuit breakers under SCC.
Common Pitfalls in Multidimensional High Resolution Channel Parameter Estimation

The structural properties of multi-path channels such as directions of arrival and departure are estimated from multidimensional channel sounder data by application of high-resolution parameter estimation methods. However, the influence to the accuracy and reliability of the results due to antenna calibration errors and mismatch of the data model which is used by the parameter estimator are often underestimated. We describe the antenna array calibration procedure and discuss common pitfalls in high-resolution multi-path direction estimation that are related to inaccurate and/or incomplete data models that result from using only subsets of the full solid angle polarimetric antenna response. Depending on the type of the antenna array used (linear, circular) this will inherently produce biased and artificially spread angular estimates.
Comparison of inductor types for phase noise optimized oscillators in SiGe at 34 GHz

In this paper two integrated auxiliary VCOs working at a center frequency of 34 GHz for use in a 240 GHz transceiver chip in SiGe technology for ultra-wideband radar applications are presented. The oscillators are using different realizations of the resonator inductance which are compared in terms of quality factor and their influence on the phase noise of the resulting oscillator output signal. The improvement in quality factor at a frequency of 34 GHz between the oscillator using microstrip transmission lines and the oscillator using spiral inductors is simulated to be around 76 % which causes a simulated absolute improvement in output signal phase noise of around 4.5 dB. Both oscillators are realized as test circuits with which the difference can be measured to be around 5 dB proving the advantage of spiral inductors in terms of quality factor for frequencies around 34 GHz resulting in an integrated VCO design providing a low phase noise of -107 dBc/Hz @ 1 MHz offset and a wide tuning range of 6.78 GHz.
Dirichlet Aspect Weighting: A Generalized EM Algorithm for Integrating External Data Fields with Semantically Structured Queries by Using Gradient Projection Method

In this paper we address the problem of document retrieval with semantically structured queries - queries where each term has a tagged field label. We introduce Dirichlet Aspect Weighting model which integrates terms from external databases into the query language model in a bayesian learning framework. For this model, the Dirichlet prior distribution is governed by parameters which depend on the number of fields in the external databases. This model needs additional examples to be augmented to the semantically structured query. These examples are obtained using pseudo relevance feedback. We formulate a loglikelihood function for the Dirichlet Aspect Weighting model and maximize it using a novel Generalized EM algorithm. Comparison of the results of Dirichlet Aspect Weighting model on TREC 2005 Genomics Track dataset with baseline methods using pseudo relevance feedback, while incorporating terms from external databases shows an improvement.
An Improved Treatment of AC Space Charge Fields in Large Signal Simulation Codes

An accurate representation of the AC space charge electric field is required in order to be able to predict the performance of linear beam tubes, including TWTs and klystrons, using a steady state simulation code like CHRISTINE (Antonsen Jr and Lebush, 1997). The model implemented in the current release version of CHRISTINE is based on the assumption that the space charge reduction factor R is insensitive to axial wavenumber k, for a small range of k near kb equiv omega/vb, where omega is the circular frequency of the wave and vb is the beam velocity. This assumption is usually a good one, but we have found cases in which the variation of R with k must be taken into account. We show how this can be done, and illustrate the effect in an example
A Novel Vector Representation of Stochastic Signals Based on Adapted Ergodic HMMs

In this letter, we propose a novel vector representation of stochastic signals for pattern recognition (PR) based on adapted ergodic hidden Markov models (HMMs). This vector representation is generic in nature and may be used with various types of stochastic signals (e.g., image, speech, etc.) and applied to a broad range of PR tasks (e.g., classification, regression, etc.). More importantly, by combining the vector representation with optimal distance metric learning (e.g., linear discriminant analysis) directly from the data, the performance of a PR system may be significantly improved. Our experiments on an image-based recognition task clearly demonstrate the effectiveness of the proposed vector representation of stochastic signals for potential use in many PR systems.
Arma Parameter Estimation Using Continuation Methods

This paper proposes and provides initial investigations into new homoropy-based algorithms for solving the nonlinear auto-regressive-moving-average (ARMA) parameter estimation problem. Nonlinear defining equations for the optimal system parameters result in a multi-modal performance suiIiice. Current numerical methods for solving these nonlinear ARMA estimation problems use gradient-based numerical methods, which cannot distinguish between local and global minima, solve related suboptimal problems, or may not converge. Homoropy-based continuation methods are globally-convergent numerical methods from which algorithms for finding the global minimum of these nonlinear ARMA estimation problems can be formed.
Empirical Correlation Between Saturation and Dielectric Properties for Vegetal Oils Rating

This paper presents a proposal for a sensor to characterize the behavior of vegetable oils in heating cycles, and try to correlate this behavior with the dielectric constant of oil. We analyzed the variation in the dielectric constant of soybean oil samples at four heating and cooling cycles in the range 20 to 120 ° C. After analyzes were performed for sunflower and corn oils checking behaving dielectric for these as well. The maximum temperature was limited to 120 ° C due to prevent melting of the sensor components. The results show that the dielectric constant increases with increasing temperature. For maximum heating temperature, the dielectric constant of the achieved samples, three times its original value. On cooling, the dielectric constant is decreased by a different heating curve. After each complete cycle of heating and cooling, it can be seen that the value of the dielectric constant undergoes a slight increase, indicating a change in the defined physical and chemical properties of the samples. The results suggest that the analysis of the dielectric constant oils can be an easy and rapid method to characterize the state of vegetable oil, and then subjected to temperature variations. However, for this it is necessary to correlate the results of the analysis described in physicochemical analysis to determine a threshold value for the dielectric constant from which the sample is degraded for food use.
Designing a composite dictionary adaptively from joint examples

We study the complementary behaviors of external and internal examples in image restoration, and are motivated to formulate a composite dictionary design framework. The composite dictionary consists of the global part learned from external examples, and the sample-specific part learned from internal examples. The dictionary atoms in both parts are further adaptively weighted to emphasize their model statistics. Experiments demonstrate that the joint utilization of external and internal examples leads to substantial improvements, with successful applications in image denoising and super resolution.
Effect of approximate impedance formulae on the accuracy of transmission line modelling

It is well known that the accuracy of frequency-dependent line models in time-domain calculations relies on the equations that define the line propagation matrix H and characteristic admittance Yc. Therefore both modal-domain and phase-domain transmission line models are affected by the assumptions in the evaluation of the series impedance Z, namely, the formulation of the internal conductor and the ground return impedance. The complexities of the exact representation of these parameters have led investigators to propose approximate formulae, and several of these are available in the technical literature. This work examines the effects of these formulae on the calculation of matrices H and Yc on the time-domain responses of the line. Several possibilities have been tested. The results show that although the approximate methods can be used for overhead lines, caution is needed for underground cable systems.
CMOS Fluorometer for Oxygen Sensing

This letter presents an integrated complementary metal-oxide semiconductor fluorometer that utilizes frequency-domain fluorescence lifetime imaging spectroscopy for oxygen-sensing applications. The implemented fluorometer chip consists of a p+/n-well/p-substrate photodiode, a phase readout circuit with integrated zero-crossing detection to extract the frequency-domain phase shift into a time-domain delay, and a high-resolution time-to-digital converter for digital quantization of the converted time delay. The fabricated fluorometer consumes less than 8.3 mW power and has a temporal resolution of 110 ps. During oxygen-sensing experiments, a ruthenium complex was used as an oxygen-sensitive dye whose lifetime was measured as a function of the of the oxygen concentration in water.
Design, Development, and Commissioning of a Substation Automation Laboratory to Enhance Learning

Automation of power systems is gaining momentum across the world, and there is a need to expose graduate and undergraduate students to the latest developments in hardware, software, and related protocols for power automation. This paper presents the design, development, and commissioning of an automation lab to facilitate the understanding of substation automation (SA). The laboratory has relay intelligent electronic devices (IEDs) that support IEC 61850 protocol, a universal secondary test kit for testing the relays, a protocol converter that can be programmed and can handle a large number of power automation protocols, a Global Positioning Systems (GPS) clock for time synchronization, and all related software. In this paper, the retrofitting of the latest relay IEDs with the existing control center software has been demonstrated. The commissioning process and the experimental setup of the SA laboratory have also been described. A post-training evaluation emphasizes that the student learning experience is helping students to gain a better understanding of the theory and to have better career prospects in power automation. The SA laboratory, which demonstrates all aspects of substation automation, is being used extensively for research and training in this emerging field.
10.5: Development of THz gyrotrons with pulse solenoids for detecting concealed radioactive materials

This paper describes the first steps in the development of high-power THz-range gyrotrons with pulsed solenoids for remote detection of concealed radioactive materials. We first discuss the detection concept based on focusing high-power THz wave beams in small spots where the wave electric field amplitude exceeds the threshold required for initiating the breakdown. The specific feature of this concept in the case of using the THz radiation is a small volume in which the electromagnetic energy is localized. As a rule, in the absence of gamma rays causing additional ionization there should be initially no free electrons in this volume to initiate the discharge. Thus, the fact that the breakdown takes place in this volume immediately after the THz source is turned on will indicate that there is an additional source of ionization (such as radioactive materials). In the paper, we report first results on the study of air ionization by concealed radioactive materials and the first results of the design of a 670 GHz gyrotron. First estimates show that the gyrotron efficiency can be in the range of 20–25% and the gyrotron power can exceed 100 kW.
Electrostatic time-domain PIC simulations of RF density-modulated electron sources with MICHELLE

There is a significant level of effort by SAIC and BWR, funded by ONR & JTO, to enhance the three dimensional (3D) finite-element (FE) electrostatic time-domain (ESTD) particle-in-cell (PIC) code MICHELLE to provide modeling and simulation of the interaction of electron emission sources in the presence of electromagnetic cavity fields. These enhancements have direct importance to the free-electron laser (FEL) based high-energy laser community, providing the capability of modeling advanced photo-emission RF electron guns and the input cavity of high-power UHF inductive output tubes (IOT), both of which are needed for the FEL injector. We will discuss these code modifications, enhancements to our emission models, recent results of benchmarking against electromagnetic codes, as well as the limitations to the model.
Comparison of SCM, SCME, and WINNER Channel Models

This paper is summarizing and comparing properties of channel models used for Beyond-3G (B3G) MIMO simulations: 3GPP spatial channel model (SCM), its extension (SCME), and models developed by WINNER. Compared models are offering complete channel model description in a sense of large-scale as well as small-scale effects in MIMO radio-channel. WINNER targeted model was supposed to provide reliable tool for estimation of system performance, covering frequencies up to 5 GHz and bandwidths of 100 MHz in different types of environment. Since SCM was originally proposed for 2 GHz range and 5 MHz bandwidth, certain extensions (SCME) were necessary. However, SCME performance was restricted since it has been design as backward compatible with SCM. That was the motivation to start using the new WINNER generic channel model, where model parameters are extracted from channel-sounding measurements covering targeted frequency range and bandwidth. This paper describes all important differences and compares features and performances of the models.
Deep Networks for Image Super-Resolution with Sparse Prior

Deep learning techniques have been successfully applied in many areas of computer vision, including low-level image restoration problems. For image super-resolution, several models based on deep neural networks have been recently proposed and attained superior performance that overshadows all previous handcrafted models. The question then arises whether large-capacity and data-driven models have become the dominant solution to the ill-posed super-resolution problem. In this paper, we argue that domain expertise represented by the conventional sparse coding model is still valuable, and it can be combined with the key ingredients of deep learning to achieve further improved results. We show that a sparse coding model particularly designed for super-resolution can be incarnated as a neural network, and trained in a cascaded structure from end to end. The interpretation of the network based on sparse coding leads to much more efficient and effective training, as well as a reduced model size. Our model is evaluated on a wide range of images, and shows clear advantage over existing state-of-the-art methods in terms of both restoration accuracy and human subjective quality.
A note on iterative fourier transform phase reconstruction from magnitude

In this correspondence, a well-known iterative procedure for Fourier transform phase reconstruction from magnitude (usually referred to as the Gerchberg-Saxton-Fienup procedure) is revisited. The convergence of this algorithm has raised some controversy in the recent literature. In this correspondence we first point out a potential source of error in the numerical implementation of the algorithm. Then, we present a conjecture which would explain why this algorithm sometimes fails.
Algebraic methods for image processing and computer vision

Many important problems in image processing and computer vision can be formulated as the solution of a system of simultaneous polynomial equations. Crucial issues include the uniqueness of solution and the number of solutions (if not unique), and how to find numerically all the solutions. The goal of this paper is to introduce to engineers and scientists some mathematical tools from algebraic geometry which are very useful in resolving these issues. Three-dimensional motion/structure estimation is used as the context. However, these tools should also be helpful in other areas including surface intersection in computer-aided design, and inverse position problems in kinematics/robotics. The tools to be described are Bezout numbers, Grobner bases, homotopy methods, and a powerful theorem which states that under rather general conditions one can draw general conclusions on the number of solutions of a polynomial system from a single numerical example.
3D MARS: immersive virtual reality for content-based image retrieval

3D MARS is an interactive visualization system for Content-Based Image Retrieval (CBIR). In 3D MARS, the user browses and queries images in an immersive 3D Virtual Reality space of CAVE. The results of the query are displayed in 3D, so that the user can see the result with respect to three different criteria such as color, texture and structure. The user can examine the result from different view angles by flying-through the space with the joystick. Based on the user’s feedback, the system dynamically reorganize its visualization scheme. By giving meanings to each axis, the user can determine which features are important. In addition, the Sphere mode visualization is provided as a powerful analyzing tool for CBIR researchers.
A Statistical Model for the Excitation of Cavities Through Apertures

In this paper, a statistical model for the coupling of electromagnetic radiation into enclosures through apertures is presented. The model gives a unified picture bridging deterministic theories of aperture radiation, and statistical models necessary for capturing the properties of irregular shaped enclosures. A Monte Carlo technique based on random matrix theory is used to predict and study the power transmitted through the aperture into the enclosure. Universal behavior of the net power entering the aperture is found. Results are of interest for predicting the coupling of external radiation through openings in irregular enclosures and reverberation chambers.
Channel Measurement Data Based Performance Evaluation of Coded Space-Time SC-MMSE MIMO Turbo Equalization

Coded space-time soft cancellation minimum mean squared error filtering (CST SC-MMSE) based turbo equalization, which exploits transmit diversity and coding gains through two turbo iteration loops, horizontal and vertical iterations, has been introduced for uplink single carrier signaling. In this paper, performance of the CST SC-MMSE equalizer is evaluated in realistic scenarios using multi-dimensional channel measurement data. Measurement data consists of snapshots measured in different channel conditions in terms of spatial and temporal properties. It is shown that the CST SC-MMSE equalizer can achieve excellent performance even at the lower SNR range due to the vertical iterations between the decoders that can achieve a coding gain on top of the diversity gain. However, performance depends on channel conditions. The impact of the horizontal and vertical iterations is studied in different channel conditions.