摘要 :
Web search engines have stored in their logs information about users since they started to operate. This information often serves many purposes. The primary focus of this survey is on introducing to the discipline of query mining ...
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Web search engines have stored in their logs information about users since they started to operate. This information often serves many purposes. The primary focus of this survey is on introducing to the discipline of query mining by showing its foundations and by analyz-ing the basic algorithms and techniques that are used to extract useful knowledge from this (potentially) infinite source of information. We show how search applications may benefit from this kind of analysis by analyzing popular applications of query log mining and their influence on user experience. We conclude the paper by, briefly, presenting some of the most challenging current open problems in this field.
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We present a planar spectro-polarimeter based on Fabry-Pérot cavities with embedded polarization-sensitive high-index nanostructures. A 7 μm-thick spectro-polarimetric system for 3 spectral bands and 2 linear polarization states...
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We present a planar spectro-polarimeter based on Fabry-Pérot cavities with embedded polarization-sensitive high-index nanostructures. A 7 μm-thick spectro-polarimetric system for 3 spectral bands and 2 linear polarization states is experimentally demonstrated. Furthermore, an optimal design is theoretically proposed, estimating that a system with a bandwidth of 127 nm and a spectral resolution of 1 nm is able to reconstruct the first three Stokes parameters with a signal-to-noise ratio of -13.14 dB with respect to the the shot noise limited SNR. The pixelated spectro-polarimetric system can be directly integrated on a sensor, thus enabling applicability in a variety of miniaturized optical devices, including but not limited to satellites for Earth observation.
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In this paper, we present a design strategy for single layer metasurface lenses based on dielectric resonators. This strategy is based on a robust optimization procedure for the resonator distribution in order to meet required per...
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In this paper, we present a design strategy for single layer metasurface lenses based on dielectric resonators. This strategy is based on a robust optimization procedure for the resonator distribution in order to meet required performances (e.g. encircled energy, bandwidth, field of view, etc.). Possible deviations due to manufacturing errors are taken into account in the design procedure. This is applied to the design of array of microlenses for maskless lithography applications. The final design shows more uniform focusing performances (bandwidth 20 nm at 395 nm – 415 nm, field of view ±60 mrad) and increased robustness against manufacturing errors, compared to designs based on analytic phase projections.
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A superoscillatory lens (SOL) is known to produce a sub-diffraction hotspot that is useful for high-resolution imaging. SOLs have not yet been directly used in a confocal reflection setup, as the SOL suffers from poor imaging prop...
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A superoscillatory lens (SOL) is known to produce a sub-diffraction hotspot that is useful for high-resolution imaging. SOLs have not yet been directly used in a confocal reflection setup, as the SOL suffers from poor imaging properties. Additionally, the illuminating intensity distribution of the SOL still has high-intensity rings called sidelobes coexisting with the central hotspot. By means of a reflection setup, which does not have the SOL in the detection chain, thereby mitigating the poor imaging properties, we assessed the resolution capabilities of a SOL. This was done for different objects, whose dimensions were both above and below the SOL field-of-view (FOV). We found that the sidelobe illumination degrades the imaging properties in the case of extended objects, limiting the applicability of a SOL system.
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The 38th European Conference on Information Retrieval took place from the 20th to the23rd of March 2016 in Padua, Italy. This report summarizes the conference in terms of thepresented keynotes, scientific and social programme, ind...
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The 38th European Conference on Information Retrieval took place from the 20th to the23rd of March 2016 in Padua, Italy. This report summarizes the conference in terms of thepresented keynotes, scientific and social programme, industry day, tutorials, workshops andstudent support.
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摘要 :
The 38th European Conference on Information Retrieval took place from the 20th to the 23rd of March 2016 in Padua, Italy. This report summarizes the conference in terms of the presented keynotes, scientific and social programme, i...
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The 38th European Conference on Information Retrieval took place from the 20th to the 23rd of March 2016 in Padua, Italy. This report summarizes the conference in terms of the presented keynotes, scientific and social programme, industry day, tutorials, workshops and student support.
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摘要 :
Counterfactual examples (CFs) are one of the most popular methods for attaching post hoc explanations to machine learning models. However, existing CF generation methods either exploit the internals of specific models or depend on...
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Counterfactual examples (CFs) are one of the most popular methods for attaching post hoc explanations to machine learning models. However, existing CF generation methods either exploit the internals of specific models or depend on each sample's neighborhood; thus, they are hard to generalize for complex models and inefficient for large datasets. This article aims to overcome these limitations and introduces
ReLAX
, a model-agnostic algorithm to generate optimal counterfactual explanations. Specifically, we formulate the problem of crafting CFs as a sequential decision-making task. We then find the optimal CFs via deep reinforcement learning (DRL) with discrete-continuous hybrid action space. In addition, we develop a distillation algorithm to extract decision rules from the DRL agent's policy in the form of a decision tree to make the process of generating CFs itself interpretable. Extensive experiments conducted on six tabular datasets have shown that
ReLAX
outperforms existing CF generation baselines, as it produces sparser counterfactuals, is more scalable to complex target models to explain, and generalizes to both the classification and regression tasks. Finally, we show the ability of our method to provide actionable recommendations and distill interpretable policy explanations in two practical real-world use cases.
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We present IntoNews, a system to match online news articles with spoken news from a television newscasts represented by closed captions. We formalize the news matching problem as two independent tasks: closed captions segmentation...
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We present IntoNews, a system to match online news articles with spoken news from a television newscasts represented by closed captions. We formalize the news matching problem as two independent tasks: closed captions segmentation and news retrieval. The system segments closed captions by using a windowing scheme: sliding or tumbling window. Next, it uses each segment to build a query by extracting representative terms. The query is used to retrieve previously indexed news articles from a search engine. To detect when a new article should be surfaced, the system compares the set of retrieved articles with the previously retrieved one. The intuition is that if the difference between these sets is large enough, it is likely that the topic of the newscast currently on air has changed and a new article should be displayed to the user. In order to evaluate IntoNews, we build a test collection using data coming from a second screen application and a major online news aggregator. The dataset is manually segmented and annotated by expert assessors, and used as our ground truth. It is freely available for download through the Webscope program.1 Our evaluation is based on a set of novel time-relevance metrics that take into account three different aspects of the problem at hand: precision, timeliness and coverage. We compare our algorithms against the best method previously proposed in literature for this problem. Experiments show the trade-offs involved among precision, timeliness and coverage of the airing news. Our best method is four times more accurate than the baseline.
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Although sort has been extensively studied in many research works, it still remains a challenge in particular if we consider the implications of novel processor technologies such as manycores (i.e. GPUs, Cell/BE, multicore, etc.)....
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Although sort has been extensively studied in many research works, it still remains a challenge in particular if we consider the implications of novel processor technologies such as manycores (i.e. GPUs, Cell/BE, multicore, etc.). In this paper, we compare different algorithms for sorting integers on stream multiprocessors and we discuss their viability on large datasets (such as those managed by search engines). In order to fully exploit the potentiality of the underlying architecture, we designed an optimized version of sorting network in the K-model, a novel computational model designed to consider all the important features of many-core architectures. According to K-model, our bitonic sorting network mapping improves the three main aspects of many-core architectures, i.e. the processors exploitation, and the on-chip/off-chip memory bandwidth utilization. Furthermore we are able to attain a space complexity of 0(1). We experimentally compare our solution with state-of-the-art ones (namely, Quicksort and Radixsort) on GPUs. We also compute the complexity in the K-model for such algorithms. The conducted evaluation highlight that our bitonic sorting network is faster than Quicksort and slightly slower than radix, yet being an in-place solution it consumes less memory than both algorithms.
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The Grid and its related technologies enable large-scale sharing of resources of various types. We envision that in the near future applications will be completely built in a bottom-up fashion using software components deployed on...
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The Grid and its related technologies enable large-scale sharing of resources of various types. We envision that in the near future applications will be completely built in a bottom-up fashion using software components deployed on various locations and interconnected to form a workflow graph. In this paper, we make some proposals on the design of a component search service, enabling users to locate the components they need to deploy an application.
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