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.     

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.     

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.     

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.     

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.     

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 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 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.     

The influence of text modality on learning with static and dynamic visualizations

In this study we investigated the influence of text modality on learning with static and dynamic visualizations in a dynamic domain, namely the physical principles underlying fish locomotion. A 2 × 2-design with type of visualization (static vs. dynamic) and text modality (spoken vs. written) as independent variables was used. Concerning learning outcomes, it was hypothesized that (1) learners presented with dynamic visualizations would outperform learners presented with static visualizations, (2) learners presented with spoken text would outperform learners presented with written text, and (3) an interaction between type of visualization and modality would occur: the superiority of dynamic over static visualizations was expected to be more pronounced for spoken compared to written text. Subjective cognitive load measures were assessed and expected to mirror the aforementioned pattern of learning outcomes in accordance with Cognitive Load Theory (i.e., higher extraneous cognitive load (ECL) related to lower learning outcomes). For transfer tasks, the first two hypotheses could be confirmed. However, there was no interaction. Moreover, ECL was rated higher by subjects when learning with static compared to dynamic visualizations, but there were no differences for ECL with respect to the text modality. The results are discussed within the framework of Cognitive Load Theory.     

一种高增益GNSS-R码相位差测高信号处理方法

提出了一种GNSS-R码相位测高信号处理方法,可有效消除导航数据位对积分过程的影响,降低动态条件下多普勒的影响以及积分过程中平方损失的影响,提高处理增益。通过机载和岸基试验对该方法进行验证,机载试验结果显示,在相同的积分条件下,测高精度比传统的非相干积分方法提高约15%;岸基试验结果显示,该方法可有效延长积分时间,实现约0.43 m的测高精度。     

一种基于零中频的数字化码元同步方法

零中频技术已经成为现在通信发展的全新方向,能够大幅度提高通信芯片的集成度和数字处理能力,本文详细讨论了在零中频射频芯片的支持下基带码元同步的一种数字化方法,最后结合计算机仿真验证了算法的有效性。     

The effect of risk on trust attitude and trust behavior in interaction with information and decision automation

Situational risk has been postulated to be one of the most important contextual factors affecting operator’s trust in automation. However, experimentally, it has received only little attention and was directly manipulated even less. To close this gap, this study used a virtual reality multi-task environment where the main task entailed making a diagnosis by assessing different parameters. Risk was manipulated via the altitude, the task was set in including the possibility of virtually falling in case of a mistake. Participants were aided either by information or decision automation. Results revealed that trust attitude toward the automation was not affected by risk. While trust attitude was initially lower for the decision automation, it was equally high in both groups at the end of the experiment after experiencing reliable support. Trust behavior was significantly higher and increased during the experiment for the decision automation supported group in the form of less automation verification behavior. However, this detrimental effect was distinctly attenuated under high risk. This implies that negative consequences of decision automation in the real world might have been overestimated by studies not incorporating risk.

     

Good vibrations: tactile feedback in support of attention allocation and human-automation coordination in event-driven domains

Observed breakdowns in human-machine communication can be explained, in part, by the nature of current automation feedback, which relies heavily on focal visual attention. Such feedback is not well suited for capturing attention in case of unexpected changes and events or for supporting the parallel processing of large amounts of data in complex domains. As suggested by multiple-resource theory, one possible solution to this problem is to distribute information across various sensory modalities. A simulator study was conducted to compare the effectiveness of visual, tactile, and redundant visual and tactile cues for indicating unexpected changes in the status of an automated cockpit system. Both tactile conditions resulted in higher detection rates for, and faster response times to, uncommanded mode transitions. Tactile feedback did not interfere with, nor was its effectiveness affected by, the performance of concurrent visual tasks. The observed improvement in task-sharing performance indicates that the introduction of tactile feedback is a promising avenue toward better supporting human-machine communication in event-driven, information-rich domains.     

The self-consistent equilibrium and diffusion code sced

The SCED code solves the equilibrium equations for a Tokamak axisymmetric configuration and the plasma diffusion equations. The equilibrium system takes into account the presence of a magnetic circuit made of iron, the currents in the poloidal coils and the plasma pressure and toroidal field profiles. The plasma boundary is a free boundary defined by its contact with a limiter. A variational formulation of the problem is written and the equations of the poloidal flux ψ are solved by a finite element method; the Picard and the Newton algorithms are tested for the treatment of the non-linearities and compared on TFR and JET equilibrium configurations. The variation of the plasma position with respect to the currents in the coils is then studied by a continuation method and the link between the convergence of the Picard method and the stability of the plasma motions is proved. The evolution problem takes into account the induction of the primary coils and the penetration of the eddy currents in the vacuum vessel. The 2D diffusion equations for the electronic and ionic densities and temperatures and for the poloidal flux are written in terms of the toroidal flux by averaging over the magnetic surfaces. These equations are solved by an implicit scheme in time and by a finite difference scheme in space; the non-linearities are treated by the Newton method. The coupling between the equilibrium system and the diffusion equations enables one to follow the evolution of the plasma boundary. The study of the plasma motions in TFR, in the presence or absence of a feedback system, has been performed with this code and compared with the experimental observations.