Active classification with comparison queries

We study an extension of active learning in which the learning algorithm may ask the annotator to compare the distances of two examples from the boundary of their label-class. For example, in a recommendation system application (say for restaurants), the annotator may be asked whether she liked or disliked a specific restaurant (a label query); or which one of two restaurants did she like more (a comparison query). We focus on the class of half spaces, and show that under natural assumptions, such as large margin or bounded bit-description of the input examples, it is possible to reveal all the labels of a sample of size $n$ using approximately $O(\log n)$ queries. This implies an exponential improvement over classical active learning, where only label queries are allowed. We complement these results by showing that if any of these assumptions is removed then, in the worst case, $\Omega(n)$ queries are required. Our results follow from a new general framework of active learning with additional queries. We identify a combinatorial dimension, called the \emph{inference dimension}, that captures the query complexity when each additional query is determined by $O(1)$ examples (such as comparison queries, each of which is determined by the two compared examples). Our results for half spaces follow by bounding the inference dimension in the cases discussed above.Comment: 23 pages (not including references), 1 figure. The new version contains a minor fix in the proof of Lemma 4.

Transition from ion-coupled to electron-only reconnection: Basic physics and implications for plasma turbulence

Using kinetic particle-in-cell (PIC) simulations, we simulate reconnection conditions appropriate for the magnetosheath and solar wind, i.e., plasma beta (ratio of gas pressure to magnetic pressure) greater than 1 and low magnetic shear (strong guide field). Changing the simulation domain size, we find that the ion response varies greatly. For reconnecting regions with scales comparable to the ion Larmor radius, the ions do not respond to the reconnection dynamics leading to ''electron-only'' reconnection with very large quasi-steady reconnection rates. The transition to more traditional ''ion-coupled'' reconnection is gradual as the reconnection domain size increases, with the ions becoming frozen-in in the exhaust when the magnetic island width in the normal direction reaches many ion inertial lengths. During this transition, the quasi-steady reconnection rate decreases until the ions are fully coupled, ultimately reaching an asymptotic value. The scaling of the ion outflow velocity with exhaust width during this electron-only to ion-coupled transition is found to be consistent with a theoretical model of a newly reconnected field line. In order to have a fully frozen-in ion exhaust with ion flows comparable to the reconnection Alfv\'en speed, an exhaust width of at least several ion inertial lengths is needed. In turbulent systems with reconnection occurring between magnetic bubbles associated with fluctuations, using geometric arguments we estimate that fully ion-coupled reconnection requires magnetic bubble length scales of at least several tens of ion inertial lengths

Differences in School Climate Means: Exploring Contextual Factors among a Sample of Appalachian Youth

The Every Student Succeeds Act (ESSA) provides a means for states to streamline current assessment systems and integrate multidimensional measures. The use of comprehensive measures (i.e. school climate) is important in understanding non-academic factors that influence the quality of a school. There are limited studies which describe how contextual factors influence the learning and behavior of students within demographically homogenous populations, especially from rural settings. Rural populations are characterized to have higher prevalence of multiple social, behavioral, and contextual characteristics that negatively affect their perception of school when compared to their urban counterparts.;The purpose of this study was to examine differences in mother\u27s education and self-reported academic achievement as it relates to race through paired comparisons of School Climate Measure (SCM) means from a sample of Appalachian youth in West Virginia. A total of 1,275 students enrolled in grades 9 - 12 were surveyed using a cross-sectional purposive cluster sample from two high schools.;A factorial ANCOVA with a significance level of .01 was performed to examine main and interaction effects between the independent (mother\u27s education and grades) and dependent variable (instrument mean), while controlling for race.;Findings suggest mother\u27s education and self-reported academic scores in mathematics play a role in influencing how students perceive the climate of the school. Calculated effect sizes within-groups ranged from medium to small, which suggests that school climate mattersfn and is related to maternal education and academic outcomes.;Given the similar differences between the within-groups analysis, further studies with similar methods may point to important implications for the delivery of instruction and school-based interventions that promote positive learning and school quality

The Death Knell and the Wild West: Two Dangers of Domestic Discovery in Foreign Adjudications

Under 28 U.S.C. § 1782(a), parties to foreign legal proceedings can obtain discovery orders from United States federal courts. In other words, if a foreign party needs physical evidence located in—or testimony from a person residing in—the United States to support their claim or defense, they can ask a district court to order the production of that evidence. For almost two decades, § 1782(a) practice has operated as a procedural Wild West. Judges routinely consider § 1782(a) applications ex parte—that is, without giving the parties subject to the resulting discovery orders a chance to oppose them—and grant those applications at a staggering rate: more than 90% of the time. In its June 2022 decision in ZF Automotive US, Inc. v. Luxshare, Ltd., the Supreme Court transformed § 1782 jurisprudence for the worse. The Court held that private arbitral tribunals do not fall under § 1782(a)’s scope and that, as a result, parties cannot obtain discovery for use in foreign private arbitration under the provision. This Note argues that, after ZF Automotive, § 1782(a) jurisprudence contains two dangers: (1) it subjects some parties to burdensome discovery orders with few procedural safeguards, and (2) it prevents parties who have chosen to arbitrate rather than litigate from obtaining discovery entirely. This Note contributes to existing scholarship by proposing structural changes that would improve § 1782(a) practice. Specifically, it argues that courts cannot root out the procedural flaws that plague § 1782(a), and that, consequently, Congress should enact a new and improved § 1782 to address these manifold problems