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Proceedings of QG2010: The Third Workshop on Question Generation
These are the peer-reviewed proceedings of "QG2010, The Third Workshop on Question Generation". The workshop included a special track for "QGSTEC2010: The First Question Generation Shared Task and Evaluation Challenge".
QG2010 was held as part of The Tenth International Conference on Intelligent Tutoring Systems (ITS2010)
Stream Aggregation Through Order Sampling
This is paper introduces a new single-pass reservoir weighted-sampling stream
aggregation algorithm, Priority-Based Aggregation (PBA). While order sampling
is a powerful and e cient method for weighted sampling from a stream of
uniquely keyed items, there is no current algorithm that realizes the benefits
of order sampling in the context of stream aggregation over non-unique keys. A
naive approach to order sample regardless of key then aggregate the results is
hopelessly inefficient. In distinction, our proposed algorithm uses a single
persistent random variable across the lifetime of each key in the cache, and
maintains unbiased estimates of the key aggregates that can be queried at any
point in the stream. The basic approach can be supplemented with a Sample and
Hold pre-sampling stage with a sampling rate adaptation controlled by PBA. This
approach represents a considerable reduction in computational complexity
compared with the state of the art in adapting Sample and Hold to operate with
a fixed cache size. Concerning statistical properties, we prove that PBA
provides unbiased estimates of the true aggregates. We analyze the
computational complexity of PBA and its variants, and provide a detailed
evaluation of its accuracy on synthetic and trace data. Weighted relative error
is reduced by 40% to 65% at sampling rates of 5% to 17%, relative to Adaptive
Sample and Hold; there is also substantial improvement for rank queriesComment: 10 page
Bitcoin: a Money-like Informational Commodity
The question "what is Bitcoin" allows for many answers depending on the
objectives aimed at when providing such answers. The question addressed in this
paper is to determine a top-level classification, or type, for Bitcoin. We will
classify Bitcoin as a system of type money-like informational commodity (MLIC)
Program synthesis from polymorphic refinement types
We present a method for synthesizing recursive functions that provably satisfy a given specification in the form of a polymorphic refinement type. We observe that such specifications are particularly suitable for program synthesis for two reasons. First, they offer a unique combination of expressive power and decidability, which enables automatic verification—and hence synthesis—of nontrivial programs. Second, a type-based specification for a program can often be effectively decomposed into independent specifications for its components, causing the synthesizer to consider fewer component combinations and leading to a combinatorial reduction in the size of the search space. At the core of our synthesis procedure is a newalgorithm for refinement type checking, which supports specification decomposition. We have evaluated our prototype implementation on a large set of synthesis problems and found that it exceeds the state of the art in terms of both scalability and usability. The tool was able to synthesize more complex programs than those reported in prior work (several sorting algorithms and operations on balanced search trees), as well as most of the benchmarks tackled by existing synthesizers, often starting from a more concise and intuitive user input.National Science Foundation (U.S.) (Grant CCF-1438969)National Science Foundation (U.S.) (Grant CCF-1139056)United States. Defense Advanced Research Projects Agency (Grant FA8750-14-2-0242
Managing Executive Transitions
A handbook for nonprofits going through or anticipating executive transitions
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