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摘要： This qualitative study explores how a group of preservice teachers, all of whom had been well prepared to become primary-grade teachers, made a transition into infant/toddler group care settings. The authors used the teachers' daily journal entries, individual interview, document analysis (course syllabus, weekly planning sheets), and weekly team planning meetings as data sources. Findings revealed that the teachers initially struggled to work with the infants/toddlers and that their long-held notions of children, teaching, and learning were challenged. Yet, their daily work with the children over 15 weeks of practicum helped them deepen and broaden, and become more skillful and insightful of early childhood education, which the teachers found applicable to primary-grade teaching.

关键词： 基础教育课程改革   行动逻辑   类型学   课程治理机制  

摘要： 在我国新一轮基础教育课程改革持续深入推进的过程中,国家、地方和学校三个课程行动主体基于利益和价值的考量,受制于制度、资源、技术等因素影响,致使课程改革呈现出差异性与多样化的行动逻辑。根据课程行动主体间的共识度和协同度两个维度,构建创新扩散型、执行落差型、孤岛效应型和构建变通型四种课程改革实践样态的理想类型。基于基础教育课程改革类型学分析的上下联动机制、问题倒逼机制、试点推广机制与协同推进机制是课程改革的有效治理机制。

关键词： Three-dimensional displays   Laser radar   Urban areas   Buildings   Image segmentation   Data mining   Feature extraction   Low-density point cloud   light detection and ranging (LiDAR)   roof superstructures   3D classification   imbalanced data  

摘要： Light Detection and Ranging (LiDAR), an active remote sensing technology, is becoming an essential tool for geoinformation extraction and urban planning. Airborne Laser Scanning (ALS) point clouds segmentation and accurate classification are challenging and crucial to produce different geo-information products like three-dimensional (3D) city designs. This paper introduces an effective data-driven approach to build roof superstructures classification for airborne LiDAR point clouds with very low density and imbalanced classes, covering an urban area. Notably, it focuses on building roof superstructures (especially dormers and chimneys) and mitigating nonplanar objects' problems. Also, the imbalanced class problem of LiDAR data, to the best of our knowledge, is not yet addressed in the literature;it is considered in this study. The major advantage of the proposed approach is using only raw data without assumptions on the distribution underlying data. The main methodological novelties of this work are summarized in the following key elements. (i) At first, an adapted connected component analysis for 3D points cloud is proposed. (ii) Twelve geometry-based features are extracted for each component. (iii) A Support Vector Machine (SVM)-driven procedure is applied to classify the 3D components. (iv) Furthermore, a new component size-based sampling (CSBS) method is proposed to treat the imbalanced data problem and has been compared with several existing resampling strategies. In this study, components are classified into five classes: shed and gable dormers, chimneys, ground, and others. The results of this investigation show the satisfying classification performance of the proposed approach. Results also showed that the proposed approach outperformed machine learning methods, including SVM, Random Forest, Decision Tree, and Adaboost.

关键词： 公路桥梁   伸缩缝   施工技术  

摘要： 伸缩缝是桥梁工程的最后工序,也是行车平顺性和安全性的重要保障,其施工质量会直接影响用户的行车体验和项目运维管理。论文介绍了桥梁伸缩缝施工工艺及关键工序的验收要点,以供参考。

关键词： 道路桥梁   伸缩缝   施工技术  

摘要： 随着经济水平的不断增长,城市各项基础设施建设也在不断的完善,其中道路桥梁的建设也是人们关注的重中之重。在市政道路桥梁施工过程中,经常会出现各种各样的问题影响人们的正常出行,也会阻碍区域经济的快速发展,所以在市政道路工程建设过程中,应加大对各种施工技术的关注力度。因此在本文中,就针对伸缩缝施工技术进行探讨和分析。