Efficient AUC Optimization for Information Ranking Applications

Adequate evaluation of an information retrieval system to estimate future performance is a crucial task. Area under the ROC curve (AUC) is widely used to evaluate the generalization of a retrieval system. However, the objective function optimized in many retrieval systems is the error rate and not the AUC value. This paper provides an efficient and effective non-linear approach to optimize AUC using additive regression trees, with a special emphasis on the use of multi-class AUC (MAUC) because multiple relevance levels are widely used in many ranking applications. Compared to a conventional linear approach, the performance of the non-linear approach is comparable on binary-relevance benchmark datasets and is better on multi-relevance benchmark datasets.Comment: 12 page

Children reason about shared preferences

Two-year-old children’s reasoning about the relation between their own and others’ preferences was investigated across two studies. In Experiment 1, children first observed 2 actors display their individual preferences for various toys. Children were then asked to make inferences about new, visually inaccessible toys and books that were described as being the favorite of each actor, unfamiliar to each actor, or disliked by each actor. Children tended to select the favorite toys and books from the actor who shared their own preference but chose randomly when the new items were unfamiliar to or disliked by the two actors. Experiment 2 extended these findings, showing that children do not generalize a shared preference across unrelated categories of items. Taken together, the results suggest that young children readily recognize when another person holds a preference similar to their own and use that knowledge appropriately to achieve desired outcomes

Mimicry and play initiation in 18-month-old infants

Across two experiments, we examined the relationship between 18-month-old infants’ mimicry and social behavior – particularly invitations to play with an adult play partner. In Experiment 1, we manipulated whether an adult mimicked the infant's play or not during an initial play phase. We found that infants who had been mimicked were subsequently more likely to invite the adult to join their play with a new toy. In addition, they reenacted marginally more steps from a social learning demonstration she gave. In Experiment 2, infants had the chance to spontaneously mimic the adult during the play phase. Complementing Experiment 1, those infants who spent more time mimicking the adult were more likely to invite her to play with a new toy. This effect was specific to play and not apparent in other communicative acts, such as directing the adult's attention to an event or requesting toys. Together, the results suggest that infants use mimicry as a tool to establish social connections with others and that mimicry has specific influences on social behaviors related to initiating subsequent joint interactions

Diamond turning in the production of x ray optics

A demonstration x-ray optic has been produced by diamond turning and replication techniques that could revolutionize the fabrication of advanced mirror assemblies. The prototype optic was developed as part of the Advanced X-ray Astrophysics Facility - Spectrographic project (AXAF-S). The initial part of the project was aimed at developing and testing the replica technique so that it could potentially be used for the production of the entire mirror array comprised of up to 50 individual mirror shells

Anisotropic random resistor networks: a model for piezoresistive response of thick-film resistors

A number of evidences suggests that thick-film resistors are close to a metal-insulator transition and that tunneling processes between metallic grains are the main source of resistance. We consider as a minimal model for description of transport properties in thick-film resistors a percolative resistor network, with conducting elements governed by tunneling. For both oriented and randomly oriented networks, we show that the piezoresistive response to an applied strain is model dependent when the system is far away from the percolation thresold, while in the critical region it acquires universal properties. In particular close to the metal-insulator transition, the piezoresistive anisotropy show a power law behavior. Within this region, there exists a simple and universal relation between the conductance and the piezoresistive anisotropy, which could be experimentally tested by common cantilever bar measurements of thick-film resistors.Comment: 7 pages, 2 eps figure

Highly-functionalised difluorinated cyclohexane polyols via the Diels–Alder reaction : regiochemical control via the phenylsulfonyl group

A difluorinated dienophile underwent cycloaddition reactions with a range of furans to afford cycloadducts whichcould be processed regio- and stereoselectively via episulfonium ions, generated by the reaction between their alkenyl groups and phenylsulfenyl chloride. The oxabicyclic products were oxidised to the phenylsulfonyl level and ring opened via E1CB or reductive desulfonative pathways to afford, ultimately, difluorinated cyclohexene or cyclohexane polyols

Mobile onsite exploration of parallel realities with Oculus Rift

This paper reports experience in developing a parallel reality system which allows its user to observe and move around their real environment whilst wearing a stereoscopic 3D head mounted display imbued with video-see through capabilities, with their position and gaze tracked by an indoor positioning system and head tracker, allowing them to alternately view their real environment and an immersive virtual reality environment from the equivalent vantage point. In so doing the challenge of the vacancy problem is addressed by lightening the cognitive load needed to switch between realities and to navigate the virtual environment. Evaluation of the usability, system performance and value of the system are undertaken in the context of a cultural heritage application; users are able to compare a reconstruction of an important 15th century chapel with its present day instantiation.Postprin

Equity and Local Access to Jesuit Higher Education: The Catalyst Pilot

College access continues to be highly stratified across racial, socioeconomic, and first-generation status. Although there are numerous studies on college readiness programs, the research on the correlation between college proximity and college access is lacking or contradictory. Moreover, minimal research exists on college readiness programs within the context of place-based community engagement at a Jesuit university. This mixed-methods, action research case study investigated how to build accessible and equitable pathways to Jesuit colleges and universities within close proximity of historically underrepresented communities, focusing primarily on first-generation, low-income students of color from Northeast Spokane, Washington. Bordieu’s theories of cultural and social capital as well as Conley’s four facets of college readiness shaped the study. The results revealed that a college immersion program could have a positive and transformative experience on high school students’ perceptions of higher education over the course of just three days, whereas interviews with high school counselors, university admission staff, and a public school district administrator indicated that long-term key strategies were essential to improving local recruitment and building a P-16 educational pipeline

Infants’ expectations about gestures and actions in third-party interactions

We investigated 14-month-old infants’ expectations toward a third party addressee of communicative gestures and an instrumental action. Infants’ eye movements were tracked as they observed a person (the Gesturer) point, direct a palm-up request gesture, or reach toward an object, and another person (the Addressee) respond by grasping it. Infants’ looking patterns indicate that when the Gesturer pointed or used the palm-up request, infants anticipated that the Addressee would give the object to the Gesturer, suggesting that they ascribed a motive of request to the gestures. In contrast, when the Gesturer reached for the object, and in a control condition where no action took place, the infants did not anticipate the Addressee’s response. The results demonstrate that infants’ recognition of communicative gestures extends to others’ interactions, and that infants can anticipate how third-party addressees will respond to others’ gestures

A rational model of preference learning and choice prediction by children

Young children demonstrate the ability to make inferences about the preferences of other agents based on their choices. However, there exists no overarching account of what children are doing when they learn about preferences or how they use that knowledge. We use a rational model of preference learning, drawing on ideas from economics and computer science, to explain the behavior of children in several recent experiments. Specifically, we show how a simple econometric model can be extended to capture two- to four-year-olds’ use of statistical information in inferring preferences, and their generalization of these preferences