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作者： Zimmermann, Armin Hotz, Thomas Department of Computer Science and Automation Systems and Software Engineering Group Technische Universität Ilmenau Helmholtzplatz 5 Ilmenau98693 Germany Institute for Mathematics Group for Probability Theory and Mathematical Statistics Technische Universität Ilmenau Weimarer Straße 25 Ilmenau98693 Germany

The standard existing performance evaluation methods for discrete-state stochastic models such as Petri nets either generate the reachability graph followed by a numerical solution of equations or use some variant of simulation. Both methods have characteristic advantages and disadvantages depending on the size of the reachability graph and type of performance measure. This article proposes a hybrid performance evaluation algorithm for the steady-state solution of Generalized Stochastic Petri Nets that integrates elements of both methods. It automatically adapts its behavior depending on the available size of main memory and number of model states. As such, the algorithm unifies simulation and numerical analysis in a joint framework. It is proved to result in an unbiased estimator whose variance tends to zero with increasing simulation time. The article extends earlier results with an algorithm variant that starts with a small maximum number of particles and increases them during the run to increase the efficiency in cases that are rapidly solved by regular simulation. The algorithm's applicability is demonstrated through case studies, including an example where it outperforms the standard methods. © 2019 Copyright held by the owner/author(s).

关键词： Petri nets

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Students' perceptions of the differences between formal and informal learning 11

Students' perceptions of the differences between formal and ...

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7th International Computing Education Research Workshop, ICER 2011

作者： Boustedt, Jonas Eckerdal, Anna McCartney, Robert Sanders, Kate Thomas, Lynda Zander, Carol Division of Technology and Environment University of Gävle Gävle Sweden Department of Information Technology Uppsala University Uppsala Sweden Department of Computer Science and Engineering University of Connecticut Storrs CT United States Mathematics and Computer Science Department Rhode Island College Providence RI United States Department of Computer Science Aberystwyth University Aberystwyth United Kingdom Computing and Software Systems University of Washington Bothell Bothell WA United States

ISBN: (纸本)9781450308298

Research has shown that most learning in the workplace takes place outside of formal training and, given the swiftly changing nature of the field, computer science graduates more than most workers, need to be able to learn computing topics outside of organized classes. In this paper we discuss students' perceptions of the difference between formal and informal learning of computing topics, based on three datasets: essays collected from a technical writing course at a single university;the results of a brainstorming exercise conducted in the same course;and semi-structured interviews conducted at six institutions in three countries. The students report strengths and weaknesses in informal learning. On the one hand, they are motivated, can choose their level of learning, can be more flexible about how they learn, and often retain the material better. On the other hand, they perceive that they may miss important aspects of a topic, learn in an ad hoc way, and have difficulty assessing their learning. © 2011 ACM.

关键词： Students

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Joint product numerical range and geometry of reduced density matrices

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science China(Physics,Mechanics & Astronomy) 2017年第2期60卷 9-17页

作者： Jianxin Chen Cheng Guo Zhengfeng Ji Yiu-Tung Poon Nengkun YU Bei Zeng Jie Zhou Joint Center for Quantum Information and Computer Science University of Maryland College Park 20740 USA Institute for Advanced Study Tsinghua University Beijing 100084 China Centre for Quantum Computation ＆ Intelligent Systems School of Software Faculty of Engineering and Information Technology University of Technology Sydney Sydney 2007 Australia State Key Laboratory of Computer Science.Institute of Software Chinese Academy of Sciences Beijing 100084 China Department of Mathematics Iowa State University Ames 50011-2140 USA Institute for Quantum Computing University of Waterloo Waterloo N2L 3G1 Canada Department of Mathematics ＆ Statistics University of Guelph Guelph N1G 2 W1 Canada Perimeter Institute for Theoretical Physics Waterloo N2L 2Y5 Canada

The reduced density matrices of a many-body quantum system form a convex set, whose three-dimensional projection is convex in R3. The boundary of may exhibit nontrivial geometry, in particular ruled surfaces. Two physical mechanisms are known for the origins of ruled surfaces： symmetry breaking and gapless. In this work, we study the emergence of ruled surfaces for systems with local Hamiltonians in infinite spatial dimension, where the reduced density matrices are known to be separable as a consequence of the quantum de Finetti＇s theorem. This allows us to identify the reduced density matrix geometry with joint product numerical range II of the Hamiltonian interaction terms. We focus on the case where the interaction terms have certain structures, such that a ruled surface emerges naturally when taking a convex hull of ∏. We show that, a ruled surface on sitting in ∏ has a gapless origin, otherwise it has a symmetry breaking origin. As an example, we demonstrate that a famous ruled surface, known as the oloid, is a possible shape of , with two boundary pieces of symmetry breaking origin separated by two gapless lines.

关键词： reduced density matrices quantum tomography numerical range quantum information oloid ruled surface

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A new online field feature selection algorithm based on streaming data

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Journal of Ambient Intelligence and Humanized Computing 2024年第2期15卷 1365-1377页

作者： Zhang, Zhenjiang Song, Fuxing Zhang, Peng Chao, Han-Chieh Zhao, Yingsi School of Software Engineering Beijing Jiaotong University Beijing100044 China Department of Electronic and Information Engineering Key Laboratory of Communication and Information Systems Beijing Municipal Commission of Education Beijing Jiaotong University Beijing100044 China School of Information Science and Engineering Fujian University of Technology Fuzhou350118 China School of Mathematics and Computer Science Wuhan Polytechnic University Wuhan430023 China Department of Electrical Engineering National Dong Hwa University Hualien97401 Taiwan School of Economics and Management Beijing Jiaotong University Beijing100044 China

The rapid development of Internet technology derived out a massive network text data. Therefore, how to classify the massive text data efficiently has important theoretical significance and application value. In order to acquire accurate classification results, the process has been divided into two parts. In terms of text representation, this paper proposes an online field feature selection algorithm (OFFS algorithm) based on streaming data, which solves the problems of low efficiency and memory consumption of traditional feature selection algorithms. With improvements in the vector space model, the new algorithm can select the real-time feature of the data and quickly generate text vector. In the aspect of classifier design, an OFFS-BP neural network text classifier based on BP neutral network and OFFS algorithm is designed. It adapts to the distributed parallel computing, reduces the training time and balances the computation efficiency and classification accuracy. Finally based on the Spark platform, the OFFS-BP neural network classifier is implemented. The experimental results show that the OFFS-BP neural network classifier is more suitable for big data environment with less computation time and higher classification efficiency. © Springer-Verlag GmbH Germany, part of Springer Nature 2018.

关键词： Neural networks

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A single channel EMI signal separation method based on directly-mean empirical mode decomposition

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Journal of Information and Computational science 2015年第17期12卷 6333-6340页

作者： Li, Hongyi Song, Ziming Zhao, Di Wang, Pidong Chen, Jiaxin LMIB School of Mathematics and Systems Science Beihang University Beijing China School of Software Beihang University Beijing China School of Reliability and Systems Engineering Beihang University Beijing China School of Computer Science and Engineering Beihang University Beijing China

ICA is a powerful decomposition method for time-domain series, except for the requirement that the number of observed signals and the source signals should be the same, which makes ICA fail to process single channel signals. In this paper, we propose a new method using directly-mean EMD, which is utilized to extract independent components from a single channel mixture. The proposed method could overcome the side effect of original EMD, and can be applied to the separation of EMI signals to locate interference sources. Simulation experimental results demonstrate the effectiveness of the proposed method, and show that the proposed method outperforms the comparison methods, such as the original EMD ICA and wavelet ICA. © 2015 by Binary Information Press.

关键词： Empirical mode decomposition

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High Dimensional Electromagnetic Interference Signal Clustering Based On SOM Neural Network

Electronics

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Electronics 2016年第1期20卷 27-31页

作者： Li, Hongyi Zhao, Di Xu, Shaofeng Wang, Pidong Chen, Jiaxin LMIB School of Mathematics and Systems Science Beihang University Beijing100191 China School of Mathematics and Systems Science Beihang University Beijing100191 China School of Software Beihang University China School of Reliability and Systems Engineering Beihang University Beijing100191 China School of Computer Science and Engineering Beihang University Beijing100191 China

In this paper, we study the spectral characteristics and global representations of strongly nonlinear, non-stationary electromagnetic interferences (EMI), which is of great significance in analysing the mathematical modelling of electromagnetic capability (EMC) for a large scale integrated system. We firstly propose to use Self-Organizing Feature Map Neural Network (SOM) to cluster EMI signals. To tackle with the high dimensionality of EMI signals, we combine the dimension reduction and clustering approaches, and find out the global features of different interference factors, in order to finally provide precise mathematical simulation models for EMC design, analysis, forecasting and evaluation. Experimental results have demonstrated the validity and effectiveness of the proposed method. © (2016) All rights reserved.

关键词： Signal interference

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Threshold concepts and threshold skills in computing 12

Threshold concepts and threshold skills in computing

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9th Annual International Conference on International Computing Education Research, ICER 2012

作者： Sanders, Kate Boustedt, Jonas Eckerdal, Anna Mccartney, Robert Moström, Jan Erik Thomas, Lynda Zander, Carol Mathematics and Computer Science Department Rhode Island College Providence RI United States Faculty of Engineering and Sustainable Development University of Gävle Gävle Sweden Department of Information Technology Uppsala University Uppsala Sweden Department of Computer Science and Engineering University of Connecticut Storrs CT United States Department of Computing Science Umeå University 901 87 Umeå Sweden Department of Computer Science Aberystwyth University Aberystwyth United Kingdom Computing and Software Systems University of Washington Bothell WA United States

ISBN: (纸本)9781450316040

Threshold concepts can be used to both organize disciplinary knowledge and explain why students have difficulties at certain points in the curriculum. Threshold concepts transform a student's view of the discipline;before being learned, they can block a student's progress. In this paper, we propose that in computing, skills, in addition to concepts, can sometimes be thresholds. Some students report finding skills more difficult than concepts. We discuss some computing skills that may be thresholds and compare threshold skills and threshold concepts. Copyright 2012 ACM.

关键词： Students

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Self-directed learning: Stories from industry 12

Self-directed learning: Stories from industry

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12th Koli Calling International Conference on Computing Education Research, Koli Calling 2012

作者： Zander, Carol Boustedt, Jonas Eckerdal, Anna Mccartney, Robert Moström, Jan Erik Sanders, Kate Thomas, Lynda Computing and Software Systems University of Washington Bothell Bothell WA United States Faculty of Engineering and Sustainable Development University of Gävle Gävle Sweden Department of InformationTechnology Uppsala University Uppsala Sweden Department of Computer Science and Engineering University of Connecticut Storrs CT United States Department of Computing Science Umeå University 901 87 Umeå Sweden Mathematics and Computer Science Department Rhode Island College Providence RI United States Department of Computer Science Aberystwyth University Aberystwyth United Kingdom

ISBN: (纸本)9781450317955

We report preliminary results from an ongoing investigation of how computing professionals perceive and value selfdirected learning, based on a qualitative analysis of interviews with ten computing professionals. The professionals expect that future colleagues will have a well-developed ability to learn on their own. They indicate that professionals use a range of resources, strategies, and collaborators to help them learn. They find their work-related self-directed learning enjoyable, expressing a sense of confidence and pride;yet they often also find it to be a stressful never-ending process. Copyright 2012 ACM.

关键词： informal learning self-directed learning industry perspective

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'Permanent' algorithm for the meeting shedule problem 16

'Permanent' algorithm for the meeting shedule problem

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16th IEEE International Conference on computer science and Information Technologies, CSIT 2021

作者： Turbal, Yuriy Babych, Sergii Kunanets, Nataliia Melnyk, Leonid Pasichnyk, Volodymyr National University of Water and Environmental Engineering Department of Computer Science and Applied Mathematics Rivne Ukraine College of National University of Life and Environmental Sciences of Ukraine Software Engineering Rivne Ukraine National University 'Lviv Polytechnic' Department of Information Systems and Networks Lviv Ukraine National University of Water and Environmental Engineering Department of Finance and Economic Security Rivne Ukraine

ISBN: (纸本)9781665442572

An algorithm for solving the problem of scheduling meetings in the process of working on a project is proposed in the paper. The problem of project managers meetings with working groups is considered under certain restrictions., the possibility of a simultaneous meeting of the project manager with one or several project groups is considered. The proposed procedure for finding the permanent allows to build all possible combinations of the meeting schedule at a given time. The specificity of the proposed approach is the ability to take into account any number of additional conditions. © 2021 IEEE.

关键词： Managers

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A Hybrid Case Based Reasoning System Using Fuzzy-Rough Sets and Formal Concept Analysis

A Hybrid Case Based Reasoning System Using Fuzzy-Rough Sets ...

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International Conference on Fuzzy systems and Knowledge Discovery (FSKD)

作者： Jirapond Tadrat Veera Boonjing Puntip Pattaraintakorn Software Systems Engineering Laboratory Department of Mathematics and Computer Science King Mongkut''s Institute of Technology Ladkrabang Bangkok Thailand Department of Mathematics and Computer Science King Mongkut''s Institute of Technology Ladkrabang Bangkok Thailand

In this paper, we propose a new hybrid case based reasoning system based on rough set theory, formal concept analysis and fuzzy sets. This system applies rough set theory to assure minimally sufficient cases in its case base. It uses formal concept analysis to reveal knowledge of attribute dependencies in terms of concept lattices. Numeric attributes are transformed to be suitable for formal concept analysis using fuzzy sets.

关键词： Fuzzy sets mathematics computer science Set theory Lattices Information systems software systems systems engineering and theory Laboratories Rough sets

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