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游戏与数学联系的魅力——五年级《多连方与游戏》教学实录
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作者 汤卫红 《江苏教育》 2019年第17期50-54,59,共6页
【课前慎思】学完北师大版五下“正方体的平面展开图”后,有学生问我:为什么正方体的平面展开图只有11种?真的找不到第12种吗?我一时语塞,不知如何回答。这个问题一直萦绕在我心头,苦苦思索后我发现:如果找出所有的六连方,再逐一确认它... 【课前慎思】学完北师大版五下“正方体的平面展开图”后,有学生问我:为什么正方体的平面展开图只有11种?真的找不到第12种吗?我一时语塞,不知如何回答。这个问题一直萦绕在我心头,苦苦思索后我发现:如果找出所有的六连方,再逐一确认它们是否为正方体的平面展开图,不就能解决了吗?那么,六连方一共有多少种呢?我花了半个小时走了不少弯路才研究出来。 展开更多
关键词 游戏 多连方 核心素养
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基于实证数据 提升数学能力——以“画周长是12的多连方”为例
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作者 梁玲智 潘慧敏 《数学教学通讯》 2021年第19期6-8,共3页
文章以拓展课“画周长是12的多连方”为例,通过对学生解答此类问题策略的分析,发现学生现有的数学能力大多停留在“数”或“算”的层面,极少能从图形变换的角度进行思考,缺乏“通过平移找到基础图形之外的多连方”的意识与能力。文章将... 文章以拓展课“画周长是12的多连方”为例,通过对学生解答此类问题策略的分析,发现学生现有的数学能力大多停留在“数”或“算”的层面,极少能从图形变换的角度进行思考,缺乏“通过平移找到基础图形之外的多连方”的意识与能力。文章将在实证研究的基础上,阐释如何通过“巧借认知经验、架构知识桥梁”“利用几何直观、同化认知结构”“建立认知阶梯、构建逻辑结构”这三个层面螺旋地提升学生的数学能力。 展开更多
关键词 周长 多连方 解题策略 数学能力
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“多连方”在小学低年段的教学实践与思考
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作者 王桂兰 《广西教育》 2019年第25期107-108,共2页
本文论述"多连方"在小学低年段教学的实践,通过算式表征连方,为四连方排序,让学生从中感悟到不同的四连方之间的变换,进一步发展学生对图形的分合、拼组和变换的认知。
关键词 多连方 教材分析 小学数学 低年级
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Multi-objective nonlinear model predictive control through switching cost functions and its applications to chemical processes 被引量:1
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作者 何德峰 余世明 俞立 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2015年第10期1662-1669,共8页
This paper proposes a switching multi-objective model predictive control(MOMPC) algorithm for constrained nonlinear continuous-time process systems.Different cost functions to be minimized in MPC are switched to satis... This paper proposes a switching multi-objective model predictive control(MOMPC) algorithm for constrained nonlinear continuous-time process systems.Different cost functions to be minimized in MPC are switched to satisfy different performance criteria imposed at different sampling times.In order to ensure recursive feasibility of the switching MOMPC and stability of the resulted closed-loop system,the dual-mode control method is used to design the switching MOMPC controller.In this method,a local control law with some free-parameters is constructed using the control Lyapunov function technique to enlarge the terminal state set of MOMPC.The correction term is computed if the states are out of the terminal set and the free-parameters of the local control law are computed if the states are in the terminal set.The recursive feasibility of the MOMPC and stability of the resulted closed-loop system are established in the presence of constraints and arbitrary switches between cost functions.Finally,implementation of the switching MOMPC controller is demonstrated with a chemical process example for the continuous stirred tank reactor. 展开更多
关键词 Nonlinear system Model predictive control Multi-objective control Switched control Continuous stirred tank reactor
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Joint Network and Fountain Codes Design for RelayAssisted Multi-User System 被引量:1
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作者 HUANG Ying LEI Jing WEI Jibo 《China Communications》 SCIE CSCD 2015年第7期96-107,共12页
In relay-assisted multi-user system, relay coding is important to enhance the robustness and reliability of cooperative transmission. For better adaptability and efficiency, two joint network and fountain coding(JNFC)... In relay-assisted multi-user system, relay coding is important to enhance the robustness and reliability of cooperative transmission. For better adaptability and efficiency, two joint network and fountain coding(JNFC) schemes are proposed. When the condition of all direct channels is worse, JNFC scheme based on distributed LT(DLT) codes is used. Otherwise, JNFC scheme based on multi-dimensional LT(MD-LT) codes is suited. For both two above-mentioned schemes, the united degree distribution design method for short-length fountain codes is proposed. For the latter scheme, MD-LT codes are proposed for equal error protection(EEP) of each user. Simulation results and analysis show that the united degree distribution need less decoding overhead compared with other degree distribution for short-length fountain codes. And then, all users are protected equally in despite of asymmetric uplinks. 展开更多
关键词 relay coding network coding fountain codes LT codes Raptor codes DLT MD-LT EEP
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EXISTENCE OF LIMIT CYCLES IN A MULTIPLY-CONNECTED REGION
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作者 ZHANG XIANG(Department of Mathematics, Naming Normal University, Naming 210097, China.) 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 1999年第2期169-172,共4页
In this paper,a conjecture about the existence of limit cycles in a multiply-connected regionproposed by Ye Yanqian is proved.
关键词 Multiply-connected region Annulus theorem Limit cycle
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