分类: 计算机科学 >> 计算机科学的集成理论 提交时间: 2022-11-29 合作期刊: 《数据智能(英文)》
摘要: Knowledge graph (KG) has played an important role in enhancing the performance of many intelligent systems. In this paper, we introduce the solution of building a large-scale multi-source knowledge graph from scratch in Sogou Inc., including its architecture, technical implementation and applications. Unlike previous works that build knowledge graph with graph databases, we build the knowledge graph on top of SogouQdb, a distributed search engine developed by Sogou Web Search Department, which can be easily scaled to support petabytes of data. As a supplement to the search engine, we also introduce a series of models to support inference and graph based querying. Currently, the data of Sogou knowledge graph that are collected from 136 different websites and constantly updated consist of 54 million entities and over 600 million entity links. We also introduce three applications of knowledge graph in Sogou Inc.: entity detection and linking, knowledge based question answering and knowledge based dialogue system. These applications have been used in Web search products to help user acquire information more efficiently.
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间: 2017-11-10
分类: 物理学 >> 核物理学 提交时间: 2023-07-24
摘要: The in-core self-powered neutron detector (SPND) acts as a key measuring device for the monitoring of parametersand evaluation of the operating conditionsof nuclear reactors. Prompt detection and tolerance of faulty SPNDsare indispensable forreliable reactor management. To completely extract the correlated state information of SPNDs, we constructeda twin model based on ageneralized regression neural network (GRNN)that represents the common relationshipsamong overall signals. Faulty SPNDswere determined because of the functional concordance of the twin model and real monitoring systems, which calculated the error probability distribution between the model outputs and real values. Faultdetection follows a tolerance phase to reinforce the stability of the twin model in the case of massive failures. Aweighted K-nearest neighbor model was employed to reasonably reconstruct the valuesof the faulty signals and guarantee data purity. The experimental evaluation of the proposed method showedpromising results,with excellentoutput consistency and high detection accuracy for bothsingle- andmultiple-point faulty SPNDs. Forunexpected excessive failures, the proposed tolerance approach can efficiently repair fault behaviors and enhance the prediction performance of the twin model.
分类: 核科学技术 >> 核探测技术与核电子学 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要: A new electrode structure CdZnTe (Cadmium Zinc Telluride) detector named Binode CdZnTe has been proposed in this paper. Together with the softwares of MAXWELL, GEANT4, and ROOT, the charge collection process and its gamma spectrum of the detector have been simulated and the detector structure has been optimized. In order to improve its performance further, Compton scattering effect correction has been used. The simulation results demonstrate that with refined design and Compton scattering effect correction, Binode CdZnTe detectors is capable of achieving 3.92% FWHM at 122 keV, and 1.27% FWHM at 662 keV. Compared with other single-polarity (electron-only) detector configurations, Binode CdZnTe detector offers a cost effective and simple structure alternative with comparable energy resolution.
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间: 2017-05-02
摘要: Gadolinium gallium aluminum garnet (GGAG) is a very promising host for the highly efficient luminescence of Ce3+ and shows potential in radiation detection applications. However, the thermodynamically metastable structure would be slanted against it from getting high transparency. To stabilize the crystal structure of GGAG, Yb3+ ions were codoped at the Gd3+ site. It is found that the decomposition of garnet was suppressed and the transparency of GGAG ceramic was evidently improved. Moreover, the photo- luminescence of GGAG:Ce3+,xYb3+ with different Yb3+ contents has been investigated. When the Ce3+ ions were excited under 475 nm, a typical near-infrared region emission of Yb3+ ions can be observed, where silicon solar cells have the strongest absorption. Basing on the lifetimes of Ce3+ ions in the GGAG:Ce3+,xYb3+ sample, the transfer efficiency from Ce3+ to Yb3+ and the theoretical internal quantum efficiency can be calculated and reach up to 86% and 186%, respectively. This would make GGAG:Ce3+,Yb3+ a potential attractive downconversion candidate for improving the energy conversion efficiency of crystalline silicon (c-Si) solar cells.