Examining infants' preferences for tempo in lullabies and playsongs.

Caregivers around the world sing to their infants. Infants not only prefer to listen to infant-directed singing over adult-directed singing, but infant-directed singing also serves a function, communicating affective information to preverbal infants to aid in adjusting arousal levels. Pitch variation has previously been identified as one performance feature that may help to convey the message. Earlier research has indicated that infants' pitch preferences are context dependent, suggesting that infants are tuned in to the communicative intent of infant-directed singing. However, there are several other performance-based features present in infant-directed singing that may also contribute to the affective message. The current study examined the role of context on infants' tempo preferences in sung playsongs and lullabies. Using a head-turn preference procedure, we measured 24 preverbal infants' natural preferences for foreign language playsongs and lullabies as a function of tempo. Infants showed a preference for fast over slow tempo playsongs, but no such context dependent preference was found within lullabies. Results partially support the role of tempo as a communicative feature of infant directed singing. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Location of the egocenter in kinesthetic space.

The location of the egocenter in kinesthetic space was investigated in 4 experiments. Participants, with their eyes closed, adjusted a comparison stimulus after or while touching a standard in a transverse plane at the belly or shoulder level so that they perceived the line joining the comparison and the fixed standard as pointing directly at themselves. The mean location of the intersections of the obtained lines was taken as the location of the egocenter. The main results showed that the location of the kinesthetic egocenter depended on the hand or hands used for touching, the timing of touching, and the distance of the standard from the participant. Implications of these results were discussed in relation to models of the kinesthetic egocenter. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Optimization of LED‐based light blendings for object presentation

This study looks at the perceived quality of light‐emitting diode (LED)‐based lighting of various colors. The objective was to find out whether LEDs could provide better (i.e., more relevant and acceptable) lighting than that which is obtained with standard halogen or fluorescent sources. The perception of objects was assessed under different lighting schemes. Subjects were invited to add red, cyan and/or amber to white LED‐based light to match the halogen and fluorescence rendering on specific targets: a color chart and a painting. They were also asked to rate the difference between the two, and to express their preference. The results obtained for the perception of LED‐based lighting were quite positive. Color blendings of LED light were found to provide illuminated situations similar to halogens or fluorescent sources. These blendings were well accepted, and indeed often preferred, although the color rendering index (CRI) was always low. This indicates that the CRI as it stands is inadequate to characterize the color rendering of solid‐state light sources, and needs to be updated. LED‐based lighting systems seem to have considerable potential for use in shops and display units, where they may well outperform existing lighting systems. © 2009 Wiley Periodicals, Inc. Col Res Appl, 34, 310–320, 2009     

A geometric approach to automated fixture layout design

Fixtures are used in many manufacturing processes to hold objects. Fixture layout design is to arrange fixturing elements (fixels) on the object surface such that the object can be held in form-closure and totally immobilized. It is well known that 4/7 fixels are sufficient for immobilizing a 2D/3D object without rotational symmetry and their locations satisfy form-closure if and only if the convex hull of their primitive wrenches forms a 3D/6D simplex in the wrench space containing the origin as an interior point. This paper presents a method for finding form-closure locations of 4/7 fixels with enhanced immobilization capability. First, the Gilbert-Johnson-Keerthi distance algorithm and the Gram-Schmidt process are used to yield the fixel locations such that the simplex with vertices at their primitive wrenches is 3D/6D and contains the origin. Then, an interchange algorithm is developed for altering the fixel locations to meet form-closure and increase an immobilization capability index of fixture layouts. The meanings of this index in fixture localization accuracy and force balance capability are elucidated as well. Its value is proved to be equal to the minimum distance from the wrench origin to the facets of the wrench simplex in terms of a unit-invariant norm for wrench vectors. Without using any general optimization techniques, this method determines an optimal fixture layout very efficiently, so that it can be tried with various initial conditions to attain a result approaching the global optimum or with other good performance qualities.     

仿生扑翼飞行机器人自主导航系统研究进展

仿生扑翼飞行机器人模仿自然界鸟类和昆虫等生物的飞行方式,具有安全性强、迷惑性好等优点,在灾害救援、反恐防 暴等方面具有极其重要的应用前景。 为实现其在未知复杂环境下的自主飞行并执行探测任务,需研制一套集感知建图、规划避 障与飞控制导等功能模块为一体的导航系统。 本文首先对扑翼飞行机器人的导航系统进行了概述,按照翼展大小将扑翼飞行 机器人分为微小型和大中型两类,其次对比分析了国内外在微小型、大中型扑翼飞行机器人导航系统方面的主要研究进展。 接 着对自主导航系统所涉及到的感知定位与建图、运动规划与避障、轨迹跟踪与飞控制导等关键技术进行了分析总结,指出其局 限性及亟待解决的问题。 最后,对未来的研究趋势进行了展望,包括提升机载嵌入式计算能力、多模态信息融合、面向多模态飞 行的流场感知、仿生视觉系统研究、群体感知与编队控制等热点方向。     

Perceptions of Beer Foam

Consumers do differentiate between beers on the basis of their foam properties. The appearance of a stable foam on beer does influence consumer's preconceptions about the flavour of that beer. Consumers differ in the criteria they apply to judge foam quality: some prefer a stable head of moderate depth which leaves no residue after drinking; others find foam lacing to be appealing.     

A 6-degree-of-freedom measurement system for the accuracy of X-Y stages

A precision 6-degree-of-freedom measurement system has been developed for simultaneous on-line measurements of six motion errors of an X-Y stage. The system employs four laser Doppler scales and two quadrant photo detectors to detect the positions and the rotations of an optical reflection device mounted on the top of the X-Y stage. Compared to the HP5528A system, the linear positioning accuracy of the developed measurement system is better than ±0.1 μm to the range of 200 mm and the vertical straightness error is within ±1.5 μm for the measuring range of ±0.1 mm. The yaw and pitch errors are about ±1 arcsec, and the roll error is about ±3 arcsec within the range of ±50 arcsec.     

直接法——外语教学的演变与发展之二(英文)

本文是“外语教学的演变与发展”的第二部分,论述直接教学法。     

Unexpected discoveries and S-invention of design requirements: important vehicles for a design process

Designers, during a conceptual design process, do not just synthesize solutions that satisfy initially given requirements, but also invent design issues or requirements that capture important aspects of the given problem. How do they do this? What becomes the impetus for the invention of important issues or requirements? So-called ‘unexpected discoveries', the acts of attending to visuo-spatial features in sketches which were not intended when they were drawn, are believed to contribute to it. The purpose of the present research is to verify this hypothesis. Analysing the cognitive processes of a practising architect in a design session, we found that in about a half of his entire design process there were bi-directional relations between unexpected discoveries and the invention of issues or requirements. Not only did unexpected discoveries become the driving force for the invention of issues or requirements, but also the occurrence of invention, in turn, tended to cause new unexpected discoveries. This has provided empirical evidence for two anecdotal views of designing. First, designing is a situated act; designers invent design issues or requirements in a way situated in the environment in which they design. We call inventions of this sort situated-invention (S-invention). Secondly, a design process progresses in such a way that the problem-space and the solution-space co-evolve. Further, this has brought a pedagogical implication as well as an insight about an important aspect of learning by experience in design.     

抽油杆接头加工方法探讨

讨论了石油采油中抽油杆接头加工中的装夹定位方法与保证加工精度和效率的措施，并结合工艺过程确定了相关尺寸和检测要求相匹配的尺寸。