Advancing Natural Language Processing in Educational Assessment examines the use of natural language technology in educational testing, measurement, and assessment. Recent developments in natural ...language processing (NLP) have enabled large-scale educational applications, though scholars and professionals may lack a shared understanding of the strengths and limitations of NLP in assessment as well as the challenges that testing organizations face in implementation. This first-of-its-kind book provides evidence-based practices for the use of NLP-based approaches to automated text and speech scoring, language proficiency assessment, technology-assisted item generation, gamification, learner feedback, and beyond. Spanning historical context, validity and fairness issues, emerging technologies, and implications for feedback and personalization, these chapters represent the most robust treatment yet about NLP for education measurement researchers, psychometricians, testing professionals, and policymakers.
Synchronized phasor measurements have become a mature technology with several international manufacturers offering commercial phasor measurement units (PMUs) which meet the prevailing industry ...standard for synchrophasors. With the occurrence of major blackouts in many power systems around the world, the value of data provided by PMUs has been recognized, and installation of PMUs on power transmission networks of most major power systems has become an important current activity. This paper provides a brief introduction to the PMU and wide-area measurement system (WAMS) technology and discusses the uses of these measurements for improved monitoring, protection, and control of power networks.
Effective monitoring and management applications on modern distribution networks (DNs) require a sound network model and the knowledge of line parameters. Network line impedances are used, among ...other things, for state estimation and protection relay setting. Phasor measurement units (PMUs) give synchronized voltage and current phasor measurements, referred to a common time reference (coordinated universal time). All synchrophasor measurements can thus be temporally aligned and coordinated across the network. This feature, along with high accuracy and reporting rates, could make PMUs useful for the evaluation of network parameters. However, instrument transformer behavior strongly affects the parameter estimation accuracy. In this paper, a new PMU-based iterative line parameter estimation algorithm for DNs, which includes in the estimation model systematic measurement errors, is presented. This method exploits the simultaneous measurements given by PMUs on different nodes and branches of the network. A complete analysis of uncertainty sources is also performed, allowing the evaluation of estimation uncertainty. Issues related to operating conditions, topology, and measurement uncertainty are thoroughly discussed and referenced to a realistic model of a DN to show how a full network estimator is possible.
Vehicle self-positioning is of significant importance for intelligent transportation applications. However, accurate positioning (e.g., with lane-level accuracy) is very difficult to obtain due to ...the lack of measurements with high confidence, especially in an environment without full access to a global navigation satellite system (GNSS). In this paper, a novel information fusion algorithm based on a particle filter is proposed to achieve lane-level tracking accuracy under a GNSS-denied environment. We consider the use of both coarse-scale and fine-scale signal measurements for positioning. Time-of-arrival measurements using the radio frequency signals from known transmitters or roadside units, and acceleration or gyroscope measurements from an inertial measurement unit (IMU) allow us to form a coarse estimate of the vehicle position using an extended Kalman filter. Subsequently, fine-scale measurements, including lane-change detection, radar ranging from the known obstacles (e.g., guardrails), and information from a high-resolution digital map, are incorporated to refine the position estimates. A probabilistic model is introduced to characterize the lane changing behaviors, and a multi-hypothesis model is formulated for the radar range measurements to robustly weigh the particles and refine the tracking results. Moreover, a decision fusion mechanism is proposed to achieve a higher reliability in the lane-change detection as compared to each individual detector using IMU and visual (if available) information. The posterior Cramér-Rao lower bound is also derived to provide a theoretical performance guideline. The performance of the proposed tracking framework is verified by simulations and real measured IMU data in a four-lane highway.
Integrating Timing Considerations to Improve Testing Practices synthesizes a wealth of theory and research on time issues in assessment into actionable advice for test development, administration, ...and scoring. One of the major advantages of computer-based testing is the capability to passively record test-taking metadata—including how examinees use time and how time affects testing outcomes. This has opened many questions for testing administrators. Is there a trade-off between speed and accuracy in test taking? What considerations should influence equitable decisions about extended-time accommodations? How can test administrators use timing data to balance the costs and resulting validity of tests administered at commercial testing centers? In this comprehensive volume, experts in the field discuss the impact of timing considerations, constraints, and policies on valid score interpretations; administrative accommodations, test construction, and examinees’ experiences and behaviors; and how to implement the findings into practice. These 12 chapters provide invaluable resources for testing professionals to better understand the inextricable links between effective time allocation and the purposes of high-stakes testing.
We present a portable Rydberg-atom-based radio frequency (RF) electric (<inline-formula> <tex-math notation="LaTeX">E </tex-math></inline-formula>) field measurement instrument (Rydberg field ...measurement system or RFMS). The RFMS comprises an atomic RF field probe (RFP) connected by a ruggedized fiber-optic patch cord to a portable mainframe control unit. The unit includes a software interface providing self-calibrated SI-traceable RF measurement and analysis, including real-time field and measurement uncertainty readout and spectral RF waveform visualization. We characterize the RFP and measure polar field and polarization patterns along primary axes of the RFP at 12.6 GHz, obtained by rotations of the RFP in the far-field of a standard gain horn antenna. Field pattern measurements at 2.5 GHz are also presented. The measured field patterns are in good agreement with finite-element simulations of the RFP, establishing that the atom-based RF <inline-formula> <tex-math notation="LaTeX">E </tex-math></inline-formula>-field probe is well-suited for SI-traceable RF measurements over multiple bands. A one-time calibration procedure and an uncertainty analysis are introduced and implemented, as required for practical atomic probe designs to realize absolute-standard SI-traceable measurement capability. This includes uncertainty contributions from the atomic-spectroscopy measurement method and analysis and from the material, geometry, and hardware design. Simultaneous RF field and polarization measurements are demonstrated. RF waveform measurement is demonstrated using example pulsed and modulated RF signals.
This article presents an in-depth study of a new vector network analyzer (VNA)-based electromagnetic material measurement method relying on a commercially available material characterization kit ...(MCK). These MCKs provide effectively a guided free-space technique with less stringent requirement on alignment compared with conventional free-space techniques. Coupled with time gating, these MCKs employ a simple calibration, composed of reflect and thru standards only, prior to taking reflection and transmission S-parameter measurements. This MCK-based method complements other conventional measurement techniques, e.g., time-domain spectroscopy (TDS) and resonant cavity, allowing fast broadband dielectric material characterization over the millimeter- and submillimeter-wave frequency ranges. In this article, a WR-15 (50-75 GHz) MCK is utilized for the measurements of S-parameters for seven types of low-loss dielectric material. Their dielectric constant and loss tangent are extracted from S-parameters and are compared against literature values. A relatively good agreement is achieved. Moreover, an investigation into the uncertainties of the extracted dielectric constant and loss tangent is performed and reported.
Antenna pattern measurement generally requires an anechoic chamber with a single line-of-sight (LOS) propagation. However, it may not be satisfied due to cost and size limitations, leading to a ...nonanechoic environment (with echoes) and a distorted measured antenna pattern. To address this challenge, this article proposed an echo suppression method using phaseless data at a single frequency. With the proposed method, one can discriminate the multipath characteristic convoluted with the actual antenna pattern by measuring the antenna gain pattern at multiple spatial locations. Different from the state-of-the-art methods requiring phase information, the proposed method is an amplitude-only technique, thus enabling cost-effective and true over-the-air (OTA) measurement for the wireless device. Furthermore, we derived a systematic guideline for the proposed method to improve measurement efficiency based on numerical simulations. The proposed method is experimentally validated by placing a metal plate in the chamber to emulate a nonanechoic environment, and a good agreement between the true antenna pattern and the reconstructed antenna gain pattern is found. Both numerical and experimental validations demonstrated the feasibility and robustness of the proposed technique.
The availability of accurate data is fundamental for several monitoring and control applications of modern power grids. Nevertheless, the knowledge of critical data, such as transmission line and ...transformer parameters, is often affected by uncertainty. This can lead to important problems in the correct management of the power systems. In spite of a monitoring infrastructure that is being renewed due to new generation devices providing synchronized measurements, the actual values of line parameters and tap changer ratios are still affected by uncertainty sources that need to be properly considered. The behavior of all the elements involved in the measurement chain must be duly modeled. This article proposes an improved method to carry out the simultaneous estimation of line parameters, tap changer ratios, and systematic measurement errors for a three-phase power system. The proposed method is based on the suitable modeling of the measurement chain and three-phase constraint equations (voltage drop and current balance) of all the components involved. Its effectiveness is confirmed by tests performed on an IEEE 14-bus test system reproduced as a three-phase system under different operative conditions.
In this paper, we devise a position-invariant method for unique and accurate complex permittivity (<inline-formula> <tex-math notation="LaTeX">\varepsilon _{r} </tex-math></inline-formula>) ...determination of low-loss samples from transmission and shorted-reflection scattering (S-) parameter measurements while mitigating the effect around Fabry-Perot frequencies. For this goal, we derived a metric function in terms of propagation factor <inline-formula> <tex-math notation="LaTeX">T </tex-math></inline-formula> only and utilized a branch-index-independent expression for unique <inline-formula> <tex-math notation="LaTeX">\varepsilon _{r} </tex-math></inline-formula> by eliminating multiple solutions problem. We measured S-parameters of two low-loss samples with substantial thickness, which both introduced a Fabry-Perot effect in the frequency range, and the measurements were conducted to validate our method and compare its accuracy with the accuracy of similar methods in the literature. We also performed an uncertainty analysis to evaluate and improve the accuracy of our method.
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