Formal verification of human-automation interaction

This paper discusses a formal and rigorous approach to the analysis of operator interaction with machines. It addresses the acute problem of detecting design errors in human-machine interaction and focuses on verifying the correctness of the interaction in complex and automated control systems. The paper describes a systematic methodology for evaluating whether the interface provides the necessary information about the machine to enable the operator to perform a specified task successfully and unambiguously. It also addresses the adequacy of information provided to the user via training material (e.g., user manual) about the machine's behavior. The essentials of the methodology, which can be automated and applied to the verification of large systems, are illustrated by several examples and through a case study of pilot interaction with an autopilot aboard a modern commercial aircraft. The expected application of this methodology is an augmentation and enhancement, by formal verification, of human-automation interfaces.     

Automation transparency: implications of uncertainty communication for human-automation interaction and interfaces

Operators of highly automated driving systems may exhibit behaviour characteristic for overtrust issues due to an insufficient awareness of automation fallibility. Consequently, situation awareness in critical situations is reduced and safe driving performance following emergency takeovers is impeded. A driving simulator study was used to assess the impact of dynamically communicating system uncertainties on monitoring, trust, workload, takeovers, and physiological responses. The uncertainty information was conveyed visually using a stylised heart beat combined with a numerical display and users were engaged in a visual search task. Multilevel analysis results suggest that uncertainty communication helps operators calibrate their trust and gain situation awareness prior to critical situations, resulting in safer takeovers. In addition, eye tracking data indicate that operators can adjust their gaze behaviour in correspondence with the level of uncertainty. However, conveying uncertainties using a visual display significantly increases operator workload and impedes users in the execution of non-driving related tasks.

Practitioner Summary: This article illustrates how the communication of system uncertainty information helps operators calibrate their trust in automation and, consequently, gain situation awareness. Multilevel analysis results of a driving simulator study affirm the benefits for trust calibration and highlight that operators adjust their behaviour according to multiple uncertainty levels.     

Exploring the role of stimulus code–response modality compatibility on the spatial Stroop effect

This study investigated the compatibility of stimulus codes and response modalities and how it mediated the spatial Stroop effect. Stimulus code (word, arrow and moving dots), response modality (voice, keypress and mouse movement), directional information (left and right) and physical location (centre, left and right) of the stimulus were manipulated. Participants responded to the directional information of the stimulus. Spatial interference was expected when the stimulus’ directional information and physical location were incongruent. Results showed that more compatible pairings for the three response modalities were word–voice, arrow–keypress and arrow–movement. Incongruent spatial location delayed the reaction time for all response modalities with the word, speeded up the vocal and keypress responses with the moving dots, and had no effect with the arrow. Arrow was thus recommended for conveying directional information on interfaces. This study demonstrated that spatial interference was mediated by the stimulus code, response modality and their compatibility.     

Preattentive processing of banner advertisements: The role of modality,location, and interference

This paper deals with the preattentive processing of banner advertisements under competitive interference conditions. In the absence of competitive interference, our experimental results were consistent with hemispheric lateralization: pictorial banner ads were evaluated more positively when positioned on the left (vs. right) side of a webpage, whereas the opposite pattern was observed for verbal banner ads. In contrast, this interaction disappeared in the presence of competitive interference. Specifically, verbal banner ads received more positive evaluations than pictorial ads when they featured products from the same category. In addition, banner ads were more liked when positioned on the left (vs. right) side when they were of the same ad modality.     

基于嵌入式图像采集处理系统的二维码识别

对基于FPGA和DSP结构的嵌入式二维码图像识别系统的硬件架构设计方案作了讨论,主要介绍了包括CMOS图像传感器,FPGA,DSP,SDRAM,FLASH,RS-232等硬件在内的各个工作模块的功能实现,并在此平台上实现了二维码图片的识读,验证了平台设计的正确性、可靠性.该系统具有通用性强,编程灵活,很适合模块化应用的特点.     

Speech-based interaction in multitask conditions: impact of prompt modality

Speech-based interaction is often recognized as appropriate for hands-busy, eyes-busy multitask situations. The objective of this study was to explore prompt-guided speech-based interaction and the impact of prompt modality on overall performance in such situations. A dual-task paradigm was employed, with tracking as a primary task and speech-based data input as a secondary task. There were three tracking conditions: no tracking, basic, and difficult tracking. Two prompt modalities were used for the speech interaction: a dialogue with spoken prompts and a dialogue with visual prompts. Data entry duration was longer with the speech prompts than with the visual prompts, regardless of whether or not there was tracking or its level of difficulty. However, when tracking was difficult, data entry duration was similar for both spoken and visual prompts. Tracking performance was also affected by the prompt modality, with poorer performance obtained when the prompts were visual. The findings are discussed in terms of multiple resource theory and the possible implications for speech-based interactions in multitask situations. Actual or potential applications of this research include the design of speech-based dialogues for multitask situations such as driving and other hands-busy, eyes-busy situations.     

Object‐oriented processing of Java source code

Code transformation and analysis tools provide support for software engineering tasks such as style checking, testing, calculating software metrics as well as reverse‐ and re‐engineering. In this paper we describe the architecture and the applications of JTransform, a general Java source code processing and transformation framework. It consists of a Java parser generating a configurable parse tree and various visitors (transformers, tree evaluators) which produce different kinds of outputs. While our framework is written in Java, the paper further opens an opportunity for a new generation of XML‐based source code tools. Copyright © 2004 John Wiley & Sons, Ltd.     

随钻脉冲曼码信号处理研究

随钻测量过程中,井下随钻测量信号通过钻井液脉冲方式传输到地面,地面采集到的信号往往包含了各种噪声和干扰,为了正确地恢复源信号,采用基于最小均方的自适应噪声对消算法.同时,利用改进锁相环方法来正确地恢复时钟,寻找准确的采样点.通过现场采集的钻井液脉冲信号进行验证,曼码信号处理能成功恢复码子,还原有效信息.     

基于AVR实现对维根信息码的采集与处理

提出一种基于高性能、低功耗AVR Atmega 8515单片机实现对维根信息码采集的解决方案.本文详细介绍了维根协议(Wiegand26)的格式和规范,给出了软件流程图、核心原程序及硬件接口电路,本方案经过在实际中运行,证明其设计是可靠的.     

The effect of stimulus modality on signal detection: implications for assessing the safety of in-vehicle technology

OBJECTIVE: This study examined the effect of two in-vehicle information systems (IVIS) on signal detection in the visual, auditory, and tactile modalities; established whether the detrimental effects of an IVIS on driving could be quantified by these detection tasks; and examined the effect of stimulus modality on signal detection. BACKGROUND: The peripheral detection task has been used widely for assessing the effects of an IVIS on driving. However, performance on this task relies on drivers' ability to see a series of LEDs, which can be problematic in field tests (e.g., on sunny days). METHOD: Participants responded to one of three detection tasks during a simulated driving experiment. The effect of IVIS interaction on these detection tasks was also measured. Reduced performance in the detection tasks was assumed to indicate a decline in drivers' ability to handle sudden events in the driving task. RESULTS: Response time to all detection tasks increased by around 200 ms when drivers performed the IVIS tasks, as compared with baseline driving. Analyses of variance and comparison of effect sizes showed the effects of these two IVISs to be the same across the three detection tasks. CONCLUSION: These detection tasks are useful for quantifying the safety of an IVIS during driving. The absence of a difference in signal detection by modality suggests that performance on these tasks relies on general attentional resources and is not modality specific. APPLICATION: The signal detection tasks employed here should be further investigated for their suitability in assessing the safety of in-vehicle systems.     

The effect of available choice on the cognitive processing of pictures

This study explores whether people orient to and encode pictures differently depending on whether the pictures were chosen from a limited or an extensive array of options. Participants viewed pictures on a computer as part of a within-subjects experiment (N = 43). In one condition, participants viewed pictures that they had chosen from a limited array of 6 options. In the other condition, participants viewed pictures chosen from an extensive array of 24 options. Heart rate and recognition served as indicators of orienting and encoding. Results showed that pictures chosen from limited options elicited orienting responses. Pictures chosen from extensive options, on the other hand, did not elicit orienting responses. Recognition was fastest and most accurate for pictures selected from limited options, suggesting that participants encoded them better. Based on these results, we suggest ways of conceptualizing the attributes of computer media that uniquely affect cognitive processing.     

Display size and distractor complexity effects on visual search

The proliferation of higher quality connected sensors is consistently increasing the amount of information available to operators, increasing the complexity of displayed information. Coupling this increase in information with larger, higher addressability displays may lead to increasingly complex visual search paradigms. The current research explored the effect of both display size and distractor symbol complexity on visual search efficiency across three different symbol set sizes. Overall, the results indicate a reduction in search efficiency as a function of both increased display size and distractor complexity, even for the high target densities employed within this study. Further, these variables can interact in target present conditions to influence search times.     

The modality effect tested in children in a user‐paced multimedia environment

The modality learning effect proposes that learning is enhanced when information is presented in both the visual and the auditory domains (e.g. pictures and spoken information) compared with presenting information solely in the visual channel (e.g. pictures and written text). Most of the evidence for this effect comes from adults in a laboratory setting. Therefore, we tested the modality effect with 80 children in the highest grade of elementary school in a naturalistic setting. In a between‐subjects design, the children either saw representational pictures with speech or representational pictures with text. Retention and transfer knowledge was tested at three moments: immediately after the intervention, one day after and after one week. The present study did not find any evidence for a modality effect in children when the lesson was learner‐paced. Instead, we found a reversed modality effect directly after the intervention for retention. A reversed modality effect was also found for the transfer questions one day later. This effect was robust, even when controlling for individual differences.     

The effect of task characteristics on conceptual conflict and information processing in online discussion

A key guidance factor of computer-supported collaborative learning (CSCL) is the specification of a discussion task. Aspects of the discussion task may affect the quality of group discussion for higher-order learning. This experiment investigated the effects of two aspects of discussion task on asynchronous text discussion of an online higher-education course. Groups completed discussion assignments that varied in degree of task context and outcome specification. Content analysis was used to assess conceptual conflict and level of information processing indicated in the online discussions. Results indicate that conceptual conflict is associated with higher-order discussion, but differences in task context and product do not have large effects on the quantity or quality of online discussion.     

The dynamics of film-induced affect and its effect on the interaction with tablet PCs

Affective states have become a crucial part of human–computer interaction research. Many studies have analysed the impact of the technology on the users' affective states as a part of what is called user experience (UX). We consider the impact of antecedent affective states on interaction with a technological artefact. We induced positive and negative affective states using film clips. Then we analysed the impact of affects on the subsequent interaction with a tablet PC. Results show that positive and negative affective states have different emotional activation patterns. Positive affect was more sensitive for changes in tasks and experimental setting. In addition, these activation patterns affected behaviour for a short time only. These findings are discussed against the background of research into UX dynamics, dynamics of affect, and user-centred design research.     

The effect of visual and interaction fidelity on spatial cognition in immersive virtual environments

Accuracy of memory performance per se is an imperfect reflection of the cognitive activity (awareness states) that underlies performance in memory tasks. The aim of this research is to investigate the effect of varied visual and interaction fidelity of immersive virtual environments on memory awareness states. A between groups experiment was carried out to explore the effect of rendering quality on location-based recognition memory for objects and associated states of awareness. The experimental space, consisting of two interconnected rooms, was rendered either flat-shaded or using radiosity rendering. The computer graphics simulations were displayed on a stereo head-tracked head mounted display. Participants completed a recognition memory task after exposure to the experimental space and reported one of four states of awareness following object recognition. These reflected the level of visual mental imagery involved during retrieval, the familiarity of the recollection, and also included guesses. Experimental results revealed variations in the distribution of participants' awareness states across conditions while memory performance failed to reveal any. Interestingly, results revealed a higher proportion of recollections associated with mental imagery in the flat-shaded condition. These findings comply with similar effects revealed in two earlier studies summarized here, which demonstrated that the less "naturalistic" interaction interface or interface of low interaction fidelity provoked a higher proportion of recognitions based on visual mental images.