143,154 research outputs found
Answering Complex Questions by Joining Multi-Document Evidence with Quasi Knowledge Graphs
Direct answering of questions that involve multiple entities and relations is a challenge for text-based QA. This problem is most pronounced when answers can be found only by joining evidence from multiple documents. Curated knowledge graphs (KGs) may yield good answers, but are limited by their inherent incompleteness and potential staleness. This paper presents QUEST, a method that can answer complex questions directly from textual sources on-the-fly, by computing similarity joins over partial results from different documents. Our method is completely unsupervised, avoiding training-data bottlenecks and being able to cope with rapidly evolving ad hoc topics and formulation style in user questions. QUEST builds a noisy quasi KG with node and edge weights, consisting of dynamically retrieved entity names and relational phrases. It augments this graph with types and semantic alignments, and computes the best answers by an algorithm for Group Steiner Trees. We evaluate QUEST on benchmarks of complex questions, and show that it substantially outperforms state-of-the-art baselines
Template Adaptation for Face Verification and Identification
Face recognition performance evaluation has traditionally focused on
one-to-one verification, popularized by the Labeled Faces in the Wild dataset
for imagery and the YouTubeFaces dataset for videos. In contrast, the newly
released IJB-A face recognition dataset unifies evaluation of one-to-many face
identification with one-to-one face verification over templates, or sets of
imagery and videos for a subject. In this paper, we study the problem of
template adaptation, a form of transfer learning to the set of media in a
template. Extensive performance evaluations on IJB-A show a surprising result,
that perhaps the simplest method of template adaptation, combining deep
convolutional network features with template specific linear SVMs, outperforms
the state-of-the-art by a wide margin. We study the effects of template size,
negative set construction and classifier fusion on performance, then compare
template adaptation to convolutional networks with metric learning, 2D and 3D
alignment. Our unexpected conclusion is that these other methods, when combined
with template adaptation, all achieve nearly the same top performance on IJB-A
for template-based face verification and identification
Can involving clients in simulation studies help them solve their future problems? A transfer of learning experiment
It is often stated that involving the client in operational research studies increases conceptual learning about a system which can then be applied repeatedly to other, similar, systems. Our study provides a novel measurement approach for behavioural OR studies that aim to analyse the impact of modelling in long term problem solving and decision making. In particular, our approach is the first to operationalise the measurement of transfer of learning from modelling using the concepts of close and far transfer, and overconfidence. We investigate learning in discrete-event simulation (DES) projects through an experimental study. Participants were trained to manage queuing problems by varying the degree to which they were involved in building and using a DES model of a hospital emergency department. They were then asked to transfer learning to a set of analogous problems. Findings demonstrate that transfer of learning from a simulation study is difficult, but possible. However, this learning is only accessible when sufficient time is provided for clients to process the structural behaviour of the model. Overconfidence is also an issue when the clients who were involved in model building attempt to transfer their learning without the aid of a new model. Behavioural OR studies that aim to understand learning from modelling can ultimately improve our modelling interactions with clients; helping to ensure the benefits for a longer term; and enabling modelling efforts to become more sustainable
Can a Suit of Armor Conduct Electricity? A New Dataset for Open Book Question Answering
We present a new kind of question answering dataset, OpenBookQA, modeled
after open book exams for assessing human understanding of a subject. The open
book that comes with our questions is a set of 1329 elementary level science
facts. Roughly 6000 questions probe an understanding of these facts and their
application to novel situations. This requires combining an open book fact
(e.g., metals conduct electricity) with broad common knowledge (e.g., a suit of
armor is made of metal) obtained from other sources. While existing QA datasets
over documents or knowledge bases, being generally self-contained, focus on
linguistic understanding, OpenBookQA probes a deeper understanding of both the
topic---in the context of common knowledge---and the language it is expressed
in. Human performance on OpenBookQA is close to 92%, but many state-of-the-art
pre-trained QA methods perform surprisingly poorly, worse than several simple
neural baselines we develop. Our oracle experiments designed to circumvent the
knowledge retrieval bottleneck demonstrate the value of both the open book and
additional facts. We leave it as a challenge to solve the retrieval problem in
this multi-hop setting and to close the large gap to human performance.Comment: Published as conference long paper at EMNLP 201
Skin-Friction and Forced Convection from Rough and Smooth Plates
The current models for skin-friction drag from a plate with a rough surface
are derived by analogy to flow within pipes having rough interiors.
But this analogy fails at low Reynolds number (Re) flow rates because the
boundary-layer must compress into the center of the pipe, while the plate
boundary-layer is unbounded. A significant discrepancy from the pipe analogy at
low Re was found by the rough plate experiments of Pimenta, Moffat, and Kays
(1975) and by experiments conducted by the present author (2019).
An additional problem is that the roughness parameter in pipe analogy
theories is tied to the drag measurements of flows inside Nikuradse's
assortment of sand-roughened pipes (1933). Prandtl and Schlichting (1934)
caution that their theory applies only to sand-roughness. More useful would be
a theory based on direct measurements of roughness profiles.
The present work derives the formula for a plate's skin-friction drag
coefficient given its root-mean-squared height-of-roughness, and Re bounds from
the roughness spatial frequency spectrum.
The present theory is in close agreement with the Mills-Hang (1983) theory,
the Pimenta et al measurements, and the experiments conducted by the author
over their respective Re ranges.
From boundary conditions of its rough plate analysis, the present work also
derives an exact formula for skin-friction from a smooth plate; this formula is
in very close agreement with measurements from Smith and Walker (1959) and
Spalding and Chi (1964) over 4 decades of Re.Comment: Rewritten to include skin-friction from smooth plates. 20 pages; 17
figures; 16 reference
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