Utilising psychophysical techniques to investigate the effects of age,typeface design,size and display polarity on glance legibility

Psychophysical research on text legibility has historically investigated factors such as size, colour and contrast, but there has been relatively little direct empirical evaluation of typographic design itself, particularly in the emerging context of glance reading. In the present study, participants performed a lexical decision task controlled by an adaptive staircase method. Two typefaces, a ‘humanist’ and ‘square grotesque’ style, were tested. Study I examined positive and negative polarities, while Study II examined two text sizes. Stimulus duration thresholds were sensitive to differences between typefaces, polarities and sizes. Typeface also interacted significantly with age, particularly for conditions with higher legibility thresholds. These results are consistent with previous research assessing the impact of the same typefaces on interface demand in a simulated driving environment. This simplified methodology of assessing legibility differences can be adapted to investigate a wide array of questions relevant to typographic and interface designs.

Practitioner Summary: A method is described for rapidly investigating relative legibility of different typographical features. Results indicate that during glance-like reading induced by the psychophysical technique and under the lighting conditions considered, humanist-style type is significantly more legible than a square grotesque style, and that black-on-white text is significantly more legible than white-on-black.     

Reading upper and lower case on Viewdata

The times taken to read aloud six passages of nonsense text presented in upper or lower case on an ITT Viewdata receiver were compared. Contrary to the usual finding with printed material, upper case text did not significantly retard reading.     

The effects of graphic metaphor,gesture interaction,and form factor on e‐book performances and preferences

Reading e‐books on touch‐based mobile devices such as smartphones and tablet personal computer (PCs) are increasing. We conducted a comparative study on the usability of e‐books provided on smartphones and tablet PCs, which are typical touch‐based mobile devices. An experiment was carried out to see the effects of graphic metaphor and gesture interaction. This study evaluated reading speed, readability, similarity, and satisfaction for 16 combinations of e‐book interfaces (two Metaphor levels × four Display size and Screen modes × two Gesture levels). Overall, performance and subjective ratings showed better results on tablet PCs with larger fonts on a larger screen than on smartphones with smaller fonts on smaller screens. In the smartphone‐landscape mode, the effect of turning a page is a factor that hinders the speed of user reading. In contrast, the users’ readability, similarity, and satisfaction were higher when the page‐turning effect was provided. It showed faster reading speeds when a flicking interaction is provided on tablet PCs. From the standpoint of readability, the portrait mode was better on smartphones. Also, the tablet PC‐portrait mode was the most satisfactory.     

Cognitive ergonomics of a mail order filling company: part 1 - influence of colour, position and highlighting on recognition time

Filling mail order request forms requires the picker to determine if the items ordered on the form are in his/her bay, reading the bin address and picking the item. An order form was investigated to determine if ergonomics improvements would result in improved productivity and accuracy. Colour, position and highlighting cues were systematically varied in a computer-simulated version of the picking task. It was concluded that colour and position significantly influence the processing time, while highlighting had no effect on processing time. Expert pickers were slower, but more accurate than the novine pickers. Recommendations for improving the order forms were made and implemented, with very encouraging results.     

The effects of Chinese typeface design,stroke weight,and contrast polarity on glance based legibility

Modern interfaces increasingly rely on screens filled with digital text to display information to users. Previous research has shown that even relatively subtle differences in the design of the on-screen typeface can influence to-device glance time in a measurable and meaningful way (Reimer et al., 2014). Here we outline a methodology for rapidly and flexibly investigating the legibility of typefaces on digital screens in glance-like contexts, and apply this method to a comparison of 5 Simplified Chinese typefaces. We find that the legibility of the typefaces, measured as the minimum presentation time needed to read character strings accurately and respond to a yes/no lexical decision task, is sensitive to differences in the typeface’s design characteristics. The most legible typeface under study (“MT YingHei”) could be read 33.1% faster than the least legible typeface in this glance-induced context. A second study examined two different weights of the MT YingHei type family (medium and bold), as well as two contrast polarity (color) conditions to investigate how these variations impact legibility thresholds. Results indicate that bold weight text is easier to read in this enforced glance-like context, and that positive polarity text (black on white) is easier to read compared to white on black text under the lighting conditions considered. These results are discussed in terms of contextual factors that may mediate glance-reading behavior, as well as how type design interacts with the practical limitations of a moderate density pixel grid.     

Effect of hypertext highlighting on browsing,reading, and navigational performance

Reading hypertext documents is more difficult than reading traditional linear text. Text highlighting plays the role of encoding for reading comprehension and may play the roles of contextual cues and landmarks for hypertext navigation. The purpose of this study was to examine the effect of text highlight and organizing highlighted text into a hierarchical structure on browsing, reading, and navigation performance in a network hypertext system. A randomized experiment was conducted. Ninety participants were randomly assigned to three conditions: a reading system with text highlighting, with text highlighting and organizing highlighted text, and without any aids. Dependent variables included browsing performance: time spent and the length of navigational path for reading; reading performance: recall and inference scores, navigational performance: scores of landmark and route knowledge and time spent and the length of navigational path for completing nine navigational tasks. The results showed that text highlight did not improve reading and navigational performance. By contrast, organizing highlighted text yielded significantly worst performance in reading and navigation. According to the results, we propose several suggestions for the design of reading instruction and digital highlighters.     

The influence of laboratory set-up in usability tests: effects on user performance,subjective ratings and physiological measures

This article examines the influences of situational factors on user behaviour in usability tests. Sixty participants carried out two tasks on a computer-simulated prototype of a mobile phone. Employing a 3 × 2 mixed experimental design, laboratory set-up was varied as a between-subjects variable (presence of facilitator and two non-interactive observers, presence of facilitator or no person present) while task difficulty was manipulated as a within-subjects variable (low vs. high). Performance data, subjective measures and physiological parameters (e.g. heart rate variability) were taken. The results showed that the presence of non-interactive observers during a usability test led to a physiological stress response, decreased performance on some measures and affected the emotional state of test participants. The presence of a facilitator (i.e. a participating observer) also influenced the emotional state of the test participant. Practitioners involved in usability testing need to be aware of undue influences of observers, in particular, if the observers are non-interactive. The findings presented in this paper have implications for the practice of usability testing. They indicated a considerable influence of observers on test participants (physiology and emotions) and on the outcomes of usability tests (performance measures). This should be considered when selecting the set-up of a usability testing procedure.     

基于决策树的敏感词变形体识别算法研究及应用

针对网络中敏感词变形体识别效率不高的问题,提出了基于决策树的敏感词变形体识别算法。首先,通过分析汉字的结构和读音等特征,研究敏感词及变形体;其次,基于敏感词库构建敏感词决策树;最后,通过多因子改进模型,对微博等新媒体的文本敏感程度进行计算。实验结果表明,该算法在识别中文敏感词及变形体时,查全率和查准率最高分别可达95%和94%,与基于确定有穷自动机的改进算法相比,查全率和查准率分别提高了19.8%和21.1%;与敏感信息决策树信息过滤算法相比,查全率和查准率分别提高17.9%和18.1% 。通过分析,该算法对敏感词变形体的识别和自动过滤是有效的。     

Search-based automated testing of continuous controllers: Framework,tool support,and case studies

ContextTesting and verification of automotive embedded software is a major challenge. Software production in automotive domain comprises three stages: Developing automotive functions as Simulink models, generating code from the models, and deploying the resulting code on hardware devices. Automotive software artifacts are subject to three rounds of testing corresponding to the three production stages: Model-in-the-Loop (MiL), Software-in-the-Loop (SiL) and Hardware-in-the-Loop (HiL) testing.ObjectiveWe study testing of continuous controllers at the Model-in-Loop (MiL) level where both the controller and the environment are represented by models and connected in a closed loop system. These controllers make up a large part of automotive functions, and monitor and control the operating conditions of physical devices.MethodWe identify a set of requirements characterizing the behavior of continuous controllers, and develop a search-based technique based on random search, adaptive random search, hill climbing and simulated annealing algorithms to automatically identify worst-case test scenarios which are utilized to generate test cases for these requirements.ResultsWe evaluated our approach by applying it to an industrial automotive controller (with 443 Simulink blocks) and to a publicly available controller (with 21 Simulink blocks). Our experience shows that automatically generated test cases lead to MiL level simulations indicating potential violations of the system requirements. Further, not only does our approach generate significantly better test cases faster than random test case generation, but it also achieves better results than test scenarios devised by domain experts. Finally, our generated test cases uncover discrepancies between environment models and the real world when they are applied at the Hardware-in-the-Loop (HiL) level.ConclusionWe propose an automated approach to MiL testing of continuous controllers using search. The approach is implemented in a tool and has been successfully applied to a real case study from the automotive domain.     

Effects of information layout,screen size,and field of view on user performance in information‐rich virtual environments

This paper describes our recent experimental evaluation of Information‐Rich Virtual Environment (IRVE) interfaces. To explore the depth cue/visibility tradeoff between annotation schemes, we design and evaluate two information layout techniques to support search and comparison tasks. The techniques provide different depth and association cues between objects and their labels: labels were displayed either in the virtual world relative to their referent (Object Space) or on an image plane workspace (Viewport Space). The Software Field of View (SFOV) was controlled to 60° or 100° of vertical angle and two groups were tested: those running on a single monitor and those on a tiled nine‐panel display. Users were timed, tracked for correctness, and gave ratings for both difficulty and satisfaction on each task. Significant advantages were found for the Viewport interface, and for high SFOV. The interactions between these variables suggest special design considerations to effectively support search and comparison performance across monitor configurations and projection distortions. Copyright © 2006 John Wiley & Sons, Ltd.     

机械工程图中形位公差符号的自动识别技术研究

根据机械工程图中形位公差符号的特点,在矢量基础上,提出并实现了一种基于关键图形特征和标注字符相结合的识别算法。该方法包括3个步骤：首先寻找该类图形的关键元素;然后根据该类图形的具体构造语法规则,由关键元素引导、逐步搜索该类图形的其他结构元素;最后用字符信息来对该类图形的有效性做出判定。试验结果表明该算法具有较好的适应性,且识别率高。     

The effects of usability and web design attributes on user preference for e-commerce web sites

This study examines the relationships among perceived usability before actual use, task completion time, and preference, and the effects of design attributes on user preference for e-commerce web sites. Nine online bookstore web sites were used by ten participants. Results indicate: (1) pre-use usability and task completion time were correlated; (2) the relationship between pre-use usability and preference was greater than that of task completion time and preference; (3) design attribute assessments after actual use were highly intercorrelated; and (4) organizational structure and layout had a greater effect on user preference than aesthetic aspects, such as color and typography. These findings can be used to construct a conceptual framework for understanding user preferences and to develop design guidelines to yield more highly preferred e-commerce web sites. Also, the methodology in this study can be applied to other computerized-applications.     

Ergonomic evaluation of electronic paper: Influences of anti‐reflection surface treatment,illumination, and curvature on legibility and visual fatigue

Abstract— The intent of this study is to investigate some critical factors that affect legibility and visual fatigue while reading on an electronic‐paper display in terms of ergonomics. Anti‐reflection surface treatment, ambient illumination, and bending curvature are taken into account to evaluate their effects by using the method of letter‐search task. The results showed that the surface treatment with high degrees of anti‐reflection significantly improved the legibility and reduces visual fatigue. Thus, electronic‐paper manufacturers may choose a much better surface treatment in order to meet ergonomic demand. In addition, the findings in the present study also indicate that subjects reported less visual fatigue on a bending surface of a visual display unit, in comparison with a plane surface. It is proven that these ergonomic evaluations for electronic paper provide manufactures with useful information to design suitable products for users.     

Productivity, satisfaction, and interaction strategies of individuals with spinal cord injuries and traditional users interacting with speech recognition software

Speech recognition is an important technology that is becoming increasingly effective for dictation-oriented activities. While recognition accuracy has increased dramatically in recent years, recent studies confirm that traditional computer users are still faster using a keyboard and mouse and spend more time correcting errors than dictating. Further, as these users become more experienced they frequently adopt multimodal strategies that require the keyboard and mouse when correcting errors. While speech recognition can be a convenient alternative for traditional computer users, it can be a powerful tool for individuals with physical disabilities that limit their ability to use a keyboard and mouse. However, research into the performance, satisfaction, and usage patterns of individuals with physical disabilities has not been reported. In this article, we report on a study that provides initial insights into the efficacy of existing speech recognition systems with respect to individuals with physical disabilities. Our results confirm that productivity does not differ between traditional users and those with physical disabilities. In contrast, numerous differences were observed when users rated their satisfaction with the system and when usage patterns were analyzed. Published online: 18 May 2001     

利用PCNN神经元点火位置信息的语音特征研究

语谱图是语音信号的时频表示,含有丰富的信息。把语谱图输入到脉冲耦合神经网络（PCNN）可以获得语音的特征矢量。传统的语音特征采用PCNN50次迭代的点火次数。提出了一种新的语音特征参数,该参数基于PCNN神经元点火位置的信息。说话人识别的实验表明,新语音特征比传统的特征更能反映话者语音信号的特点,获得更好的识别结果。     

基于USB3.0和FPGA的传动误差检测系统的设计

为提高机床传动误差检测的速度、实时性以及精度,同时为优化硬件电路的结构,并保证采样数据毫无损失地传至上位机系统,提出了一种高速实时检测方案;通过脉冲插补的思想,提出一种传动误差检测的方法;另外在一块高性能FPGA芯片内部搭建数据预处理以及控制模块,利用USB3.0芯片作传输媒介,有效地减少了该系统外围电路复杂程度,降低了开发难度;并对该系统进行模拟仿真试验;试验结果表明:根据设定的误差曲线换算后的数据,通过另一个FPGA发送至该系统,处理后得到的数据不需要经过后期补偿,其误差曲线很好地归零并形成一条闭合曲线,而低速端转速误差曲线也正确反映了仿真实验的情况;实验结果表明该系统实现了高速实时检测,为机床传动误差检测提供了技术上的支持。     

基于PCA和LDA结合的人脸识别方法的比较研究

针对用于人脸识别的主分量分析(PCA)计算量大、识别效果不佳和分类时间长,线性判别分析(LDA)存在小样本问题,比较研究几种基于PCA和LDA的人脸识别方法,这些方法包括PCA+ LDA、2DPCA+ DLDA和2DPCA+2DLDA.在理论和实验上比较研究这些方法,且在ORL和Yale人脸库的实验数据表明,结合后的方法比结合前的方法分类效果好,分类时间短,且在这几种方法中,2DPCA+2DLDA的效果最佳.     

基于图像不变矩和神经网络的零件位姿自动识别

零件位置的自动识别是智能三坐标测量机检测系统中极为关键的技术.根据零件可能的放置方式形成零件的多幅虚拟图像,利用CCD摄像机采集零件的实际图像.将图像不变矩理论应用于图像匹配技术中,以虚拟图像的矩不变量及其对应模式进行BP神经网络的训练,将训练好的网络作为分类器,根据实际采集图像的矩不变量进行零件姿态的识别;由采集图像的不变矩计算零件在像平面内的位置和方向,并经坐标转换得到零件在机器坐标系中的位置和方向.实验结果表明本文零件位置自动识别方法是智能且高效的.     

基于FPGA的并行总线QBus接口板的设计与实现

电子模块系统并行总线（QBus总线）是某型飞机火控电子设备的专用数据通信总线。研制QBus总线接口板用于QBus总线的总线控制、终端仿真及数据监控。介绍了QBus总线接口板的功能,给出了总体设计方案。采用自上向下（Top-Down）的EDA技术,逐步将问题细化,对各功能模块进行了详细划分和设计,用VHDL语言描述硬件电路,最终用FPGA实现了QBus总线技术。通过测试和联调,该板卡可以与某型飞机火控电子设备正常稳定通信。     

基于RTX和VMIC的虚拟试验联邦支撑环境研究

半实物试验对联邦支撑环境有毫秒级推进的需求,这一需求很难通过对网络环境的改善完成;针对原有基于VMIC的虚拟试验联邦支撑环境在操作系统环节的不确定性,提出了基于RTX操作系统和VMIC网络的实时扩展方案;分析了联邦运行必须的四大管理服务的模块划分,将不同模块划分到不同操作系统;针对时间服务的精度问题进行进一步研究,达到了毫秒级的时间推进;设计并实现了联邦支撑环境;对该环境的实际使用中的测试表明,其达到了半实物试验的要求。