强干扰环境下声源可视化重建方法的研究进展

准确识别噪声源是机电产品噪声控制的关键,其中,近场声全息和波束形成是两种常用的声源可视化重建方法,分别适用于近场低频和远场高频声源重建的情况。传统的声全息和波束形成方法基于自由场假设,即适用于目标声源辐射声与干扰噪声之间的信噪比大于10 dB的情况。然而很多机电产品的噪声测试只能在工作现场进行,不满足自由场条件。为此,从声学传播方程和信号处理两个方面出发,回顾了强干扰环境下声源可视化重建方法的研究发展历程,评点了每种方法的特点和适用范围。重点介绍了强干扰环境下的近场声全息方法,包括声场分离法和逆块传递函数法。另外,还介绍了混响环境下的声源重建方法以及基于信号处理的信号噪声分离方法。最后,讨论了强干扰环境下声源重建有待解决的问题及其发展趋势。     

极端热环境热应力研究指标及评价

极端热环境是某些特殊条件下人所处的恶劣环境,对极端热环境的研究和评价涉及到劳动安全和工作的可靠性。热应力是人体所承受极端热环境的一种程度上的描述。对湿球黑球温度,Sreq指数和ISO9886标准的生理指标等五种极端热环境指标的使用方法和特点进行了分析与评价,对这些指标使用的局限性进行了讨论。认为对极端热环境的研究,应联合使用不同指标后进行综合评价,并重点考虑人体生理反应的变化,使研究工作具有更加普遍的意义和实用性。为此,提出了对极端热环境评价体系研究工作的建议和今后的工作方向。     

由陆巷古村看传统村落人居环境的生命栖居

传统村落是人居环境活态、立体的宝库,是可堪栖居理想家园的设计源泉。在社会转型的特殊时期和全面建设美丽乡村的关键阶段,希望通过对陆巷古村人居环境的相关探讨,管中窥豹分析中国传统人居文化的生命观及中华民族的存续智慧,以期为赋能乡村振兴,助推家园营建,赓续民族血脉提供探索及思考。以陆巷古村为锚点,尝试探讨传统村落人居环境的生命栖居模式,分析传统村落人居环境地缘适应的显性脉络及人伦秩序的隐形脉络,解析村落人居环境的生长形式;继而从人居环境的择址与营建两大方面认知村落人居环境对生命的守护。对村落人居环境与人之间的双元互动进行剖析,读取人的生命指向在人居环境上的投射表达,以及人居环境反作用于人的生命指向的交互影响,最终得出传统村落人居环境与居住者相辅相成、共生共荣的生命栖居模式。     

不同环境下宽径比对碳纤维增强环氧树脂复合材料开孔层压板压缩失效的影响

复合材料结构强度的参数影响研究是结构设计的必要内容,然而还缺乏在不同湿热环境条件下结构尺寸对其强度的影响研究。采用数值和试验方法研究了宽径比(W/D)对不同湿度、温度时T800/X850碳纤维增强环氧树脂复合材料(CF/EP)开孔层压板压缩强度的影响。设计了参数影响研究试件,通过试验获得了不同湿热条件下的开孔层压板压缩失效结果;并利用现有的考虑湿热影响的复合材料渐进损伤方法,建立了湿热及几何参数影响的渐进损伤模型,通过将预测结果与试验结果对比验证了模型正确性。进一步结合试验和数值分析,揭示了不同湿热条件下几何参数的影响规律。研究表明:湿热环境对T800/X850 CF/EP开孔板的压缩失效载荷影响显著,相比于室温干态(RTD),室温湿态(RTW)和高温湿态(ETW)压缩失效载荷分别下降了7.75%和14.68%; RTW和RTD失效形式接近, ETW失效形式不同且失效面积更大; RTW和RTD时压缩失效强度随W/D的增大而增大,增大速度相似, ETW增大速度比前两者慢。     

OLES: an instrument for refining the design of e-learning environments

Abstract Designing and implementing effective e-learning is a complex process, which involves many factors. Lecturers need to constantly consider, evaluate and adjust these factors to provide effective e-learning environments for students. In this paper, we report on the design and development of the Online Learning Environment Survey (OLES), an instrument which can be used to gather and represent data on students' 'actual' (experienced) and 'preferred' (ideal) learning environments. We describe the use of this instrument in blended learning environments with university classes, illustrating how OLES can be used by educators striving for good practice in the design of effective online learning environments.     

Faceless students, virtual places: Emergence and communal accountability in online classrooms

A pedagogical problem growing out of virtual classrooms is the temptation to act without communal accountability, the reciprocal commitment among individuals to maintain the health of their interconnections. Drawing on an ethnographic study of a fully online composition class, I argue that teachers can encourage accountability within virtual sites by conceiving of the online classroom as an emergent phenomenon. The relationships and activities among language, physical reality, and interpretant provide the matrix out of which place organizes itself. This ecological orientation provides local and systemic strategies for fostering communal health. I begin my exploration of online place by describing the value of complex systems theory and emergence for conceptualizing place. Next, I describe the roles of language, physical reality, and interpretant, pointing out the contribution of each to the configuration of virtual place and to communal accountability. Then, I focus on the emergence of place, which reorganizes language, reality, and interpretant, opening up a new dimension to communal accountability.     

Storytelling in virtual environments from a virtual guide perspective

This paper describes our proposal for storytelling in virtual environments from a virtual guide perspective, detailing the involved knowledge representation and algorithms. In our model the guide begins at a particular location and starts to navigate the world telling the user stories related to the places she visits. Our guide tries to emulate a real guides behaviour in such a situation. In particular, she behaves as a spontaneous real guide who knows stories about the places in the virtual world but has not prepared an exhaustive tour nor a storyline.