三维激光打标机的纹理映射技术研究

在分析国内外任意三维曲面激光打标现状的基础上,通过介绍基于三维激光振镜系统自动变焦原理和面向三维激光打标加工的三维纹理数学模型的生成过程,研究了产品三维stl面展开的纹理映射算法,实现了产品三维曲面无尺寸变形和形状扭曲的激光打标方法。     

科技编辑平衡范畴方法

科技编辑平衡范畴方法必须遵循6条基本规则:明确对象,弄清性质,符合目的,服从整体,动态调控,保持比例.编辑应增强平衡意识,注意对平衡问题进行调控和检查.     

A Comparison of Beginning and Expert Supervisors’ Supervision Cognitions

Beginning and expert supervisors’ cognitions and cognitive structures were compared via concept mapping, a mixed methods design. Both beginning and expert supervisors reported a variety of cognitions representing developmental characteristics in 3 areas: assessment of supervisees, conceptualization and management of supervision, and supervisory relationship.     

Mapping continuity and change in the intellectual structure of the knowledge base on problem-based learning, 1974–2019: A systematic review

Problem-based learning (PBL) emerged during the 1970s in response to demands for active learning methods capable of developing transferable knowledge and skills in the training of doctors. Over succeeding decades, PBL was gradually adopted in other fields of education. This systematic review aimed to identify key streams of theory and empirical research that have emerged over time in PBL research and practice. The review sourced 12,036 Scopus-indexed documents published between 1974 and 2019. Science mapping was used to reveal the ‘intellectual structure’ or key research themes that have evolved in this literature over the past 45 years. The science mapping tool used in this review was author co-citation analysis conducted in VOSviewer software. Author co-citation analysis identified three schools of thought that together describe the intellectual structure of the PBL knowledge base: Design of PBL Curriculum and Instruction; PBL Effectiveness; Theory and Practice in Active Learning. In addition to portraying the intellectual structure of the literature as a whole, the review also conducted longitudinal analyses aimed at highlighting structural changes in this field over time. These analyses found that although the size and impact of schools of thought associated with Design of PBL Curriculum and Instruction and PBL Effectiveness increased over time, they remained stable in terms of theoretical foci. However, the Active Learning school evolved from a small school of authors associated with Cognitive Learning Theories prior to 2000 into the largest school of thought during the most recent decades. These findings both reaffirm the theoretical underpinnings of the PBL knowledge base and highlight its increasing integration with other forms of active learning.     

The relationship between inertial measurement unit-derived ‘force signatures’ and ground reaction forces during cricket pace bowling

Abstract

This study assessed the reliability and validity of segment measured accelerations in comparison to front foot contact (FFC) ground reaction force (GRF) during the delivery stride for cricket pace bowlers. Eleven recreational bowlers completed a 30-delivery bowling spell. Trunk- and tibia-mounted inertial measurement units (IMUs) were used to measure accelerations, converted to force, for comparisons to force plate GRF discrete measures. These measures included peak force, impulse and the continuous force–time curve in the vertical and braking (horizontal) planes. Reliability and validity was determined by intra-class correlation coefficients (ICC), coefficient of variation (CV), Bland–Altman plots, paired sample t-tests, Pearson’s correlation and one-dimensional (1D) statistical parametrical mapping (SPM). All ICC (0.90–0.98) and CV (4.23–7.41%) were acceptable, except for tibia-mounted IMU braking peak force (CV = 12.44%) and impulse (CV = 18.17%) and trunk vertical impulse (CV = 17.93%). Bland–Altman plots revealed wide limits of agreement between discrete IMU force signatures and force plate GRF. The 1D SPM outlined numerous significant (p < 0.01) differences between trunk- and tibia-located IMU-derived measures and force plate GRF traces in vertical and braking (horizontal) planes. The trunk- and tibia-mounted IMUs appeared to not represent the GRF experienced during pace bowling FFC when compared to a gold-standard force plate.     

图书馆危机的成因分析

在高风险社会,审视图书馆面临的危机,积极制定危机管理方案,既是图书馆发展的战略考虑,又是图书馆生存的战术思量。本文论述了危机、图书馆危机及图书馆危机管理的基本涵义与特征,并对图书馆危机的类别与成因作了相应的探讨。     

俄汉语评价范畴对比研究

评价范畴在语言学中具有极其重要的地位,它的研究对象主要为:明确界定评价意义的性质与其外延范围;区分主观意义与客观意义的关系;从词汇与语句层面分析评价意义的语言展现特征;揭示评价意义在各种语言意义结构中的地位等。俄汉语评价范畴对比研究是目前语言学研究领域的一项前沿性研究,具有较强的创新性,部分成果必将填补俄语语义学、汉语语义学、俄汉对比语言学的空白。     

Banach空间中有限族渐近非扩张映象的修正Reich-Takahshi迭代程序的收敛性

本文研究了Banach空间中有限族渐近非扩张映象的修正Reich-Takahashi迭代程序收敛到有限族渐近非扩张映象的公共不动点的充分条件，改进和扩广了已有文献的相关结果。     

对韩礼德“阶和范畴语法”理论的批评

Halliday的“现代汉语语法范畴”揭开了阶和范畴语法理论研究的序幕 ,其主要目的是说明语言是什么 ,语言如何工作。该理论一提出 ,就受到当代数位语言大师的批评 ,该文简要回顾了Postal,Matthews等对级阶理论的批评 ;Butler等对类概念的批评 ;Huddle ston ,Palmer等对结构概念的批评和Postal对分类性质的批评。