Decline in accuracy of automatic speech recognition as a function of time on task: fatigue or voice drift?

Recognition accuracy of speech recognition devices tends to decline during an extended period of continuous use. Although this deterioration in performance is commonly acknowledged, there has been little systematic observation of the phenomenon, and no clear account of its causes is available. The aim of the present study was to provide some indication of the magnitude and time course of this decline in performance, and to clarify the nature of underlying changes in speech behaviour. There experiments are described. Experiment 1 confirmed that there is a fall-off in recognition accuracy during a half-hour session of a data entry task, and that this occurs for both naive and practised subjects. In Experiment 2, no recovery was observed in recognition performance when short rest breaks were scheduled, indicating that vocal fatigue was not a major factor. The effects of template retraining in mid-session were investigated in Experiment 3. This procedure was found to be effective in restoring recognition accuracy, and the retrained templates were relatively robust. The implications of these findings for operational use of speech recognition devices are briefly discussed. For most applications, one-off template retraining is seen as a more appropriate solution to the problem of voice drift than more complex solutions based on adaptive templates.     

Drivers' and non-drivers' performance in a change detection task with static driving scenes: is there a benefit of experience?

The ‘looked-but-failed-to-see’ phenomenon is crucial to driving safety. Previous research utilising change detection tasks related to driving has reported inconsistent effects of driver experience on the ability to detect changes in static driving scenes. Reviewing these conflicting results, we suggest that drivers' increased ability to detect changes will only appear when the task requires a pattern of visual attention distribution typical of actual driving. By adding a distant fixation point on the road image, we developed a modified change blindness paradigm and measured detection performance of drivers and non-drivers. Drivers performed better than non-drivers only in scenes with a fixation point. Furthermore, experience effect interacted with the location of the change and the relevance of the change to driving. These results suggest that learning associated with driving experience reflects increased skill in the efficient distribution of visual attention across both the central focus area and peripheral objects.     

Can a short nap and bright light function as implicit learning and visual search enhancers?

The present study examined effects of a short nap (20 min) and/or bright light (2000 lux) on visual search and implicit learning in a contextual cueing task. Fifteen participants performed a contextual cueing task twice a day (1200–1330 h and 1430–1600 h) and scored subjective sleepiness before and after a short afternoon nap or a break period. Participants served a total of four experimental conditions (control, short nap, bright light and short nap with bright light). During the second task, bright light treatment (BLT) was applied in the two of the four conditions. Participants performed both tasks in a dimly lit environment except during the light treatment. Results showed that a short nap reduced subjective sleepiness and improved visual search time, but it did not affect implicit learning. Bright light reduced subjective sleepiness. A short nap in the afternoon could be a countermeasure against sleepiness and an enhancer for visual search.

Practitioner Summary: The study examined effects of a short afternoon nap (20 min) and/or bright light (2000 lux) on visual search and implicit learning. A short nap is a powerful countermeasure against sleepiness compared to bright light exposure in the afternoon.     

Computational modeling of elastic constants as a function of temperature and composition in Zr–Nb alloys

We used CALPHAD-type model to describe single crystal elastic constants of bcc solution phases in Zr–Nb system. The model parameters were evaluated by utilizing least square algorithm based on available experimental and first-principles data. The composition-polycrystalline elastic properties profiles of the Zr–Nb alloys of full composition were predicted and are in agreement with experimental data. The critical temperature corresponding to the dynamical stabilization of bcc pure Zr can be estimated to 600 K and the critical composition corresponding to the dynamical stabilization of bcc Zr–Nb alloys at room temperature is about 4 at% Nb. The current calculations present an effective strategy to design biomedical alloys using a computational method.     

Shared steering control: How strong and how prompt should the intervention be for a better driving experience?

The lane keeping assistance system, a representative advanced driver assistance system, comprises a shared control that cooperates with the driver to achieve a common goal. The steering experience of the driver may vary significantly depending on the auto-steering control strategy of the system. In this study, we examined the driving experience with various steering control strategies. Nine control strategies (three torque amounts × three deviations in starting control) were established as prototypes. Eighteen drivers participated in the evaluation of each strategy in a highway environment on a driving simulator. A two-way repeated measure ANOVA was used to assess the effects of the system. Both the objective measures (standard deviation of lane position, steering reversal rate, and root mean square of lateral speed) and subjective measures (pleasure and arousal of emotion, trust, disturbance, and satisfaction) were evaluated and analyzed. The results showed that a torque amount of 3 Nm evoked feelings of high disturbance and negative emotional responses. A deviation in starting control (DEV) of 0.80 m yielded unstable lane keeping performances and evoked negative effects on pleasure, trust, and satisfaction. A regression model for the driver satisfaction recommended a torque of 2.32 Nm and a DEV of 0.27 m as the optimal design parameters. This proposed strategy is expected to improve the experience design of lateral semi-autonomous vehicles.     

What does it mean to be good at using a mobile device? An investigation of three levels of experience and skill

An increasing number of computer users lack formal training in operating their devices. These daily users cannot be described as novices or experts within the predominant view of expertise. In order to describe and better understand this type of self-taught intermediate level of skill, 10 casual users of a high-end smartphone series were compared to 10 novices and 4 professionals (help desk personnel) in their learning histories, task performance, and cognitive outcomes. Our study suggests that this type of self-taught intermediate level of skill is device-specific. Experienced users (casual users and experts) exhibited superior performance for representative tasks. This is mainly attributable to faster navigation and better knowledge of interface terminology, not to deeper conceptual representation of the problems. Interviews suggest that this skill is the consequence of routine use and three recurring learning events: familiarization, following of media, and ad hoc problem-solving situations. We conclude by discussing why intermediate levels of skill deserve more attention in HCI research.     

What input errors do you experience? Typing and pointing errors of mobile Web users

Small devices such as personal digital assistants (PDAs) are widely used to access the World Wide Web (Web). However, accessing the Web from small devices is affected by poor interface bandwidth, such as small keyboards and limited pointing devices. There is little empirical work investigating the input difficulties caused by such insufficient facilities, however, anecdotal evidence suggests that there is a link between able-bodied users of the mobile Web and motor impaired users of the Web on desktop computers. This being the case we could transfer the solutions which already exists for motor impaired users into the mobile Web and vice versa. This paper presents a user study that investigates the input errors of mobile Web users in both typing and pointing. The study identifies six types of typing errors and three types of pointing errors shared between our two user domains. We find that mobile Web users often confuse the different characters located on the same key, press keys that are adjacent to the target key, and miss certain key presses. When using a stylus, they also click in the wrong places, slide the stylus during multiple clicks, and make errors when dragging. Our results confirm that despite using different input devices, mobile Web users share common problems with motor impaired desktop users; and we therefore surmise that it will be beneficial to transfer available solutions between these user domains in order to address their common problems.     

To simplify or not? Facilitating English L2 users' comprehension and processing of open educational resources in English using text simplification

Open Educational Resources (OER) aim to provide equal access to education. Yet, as the language level used in OER presents a barrier to many learners, there is a need to make these resources more comprehensible. This study combined eye-tracking methodology and comprehension assessment to explore the effect of text simplification on English second language (L2) users, while also accounting for text organizational structure and individual predispositions. A total of 37 adult English L2 users took part in the study. They had to read either an authentic narrative, authentic expository OER or their linguistically simplified versions. The analysis showed that simplification led to better text comprehension, and text narrativity facilitated text recall, particularly at lower English proficiency levels. Eye-tracking measures revealed that text simplification led to an increase in processing time during the initial reading of the text and a decrease in processing time during text re-inspection. These findings have strong practical applications for online teaching with OER.     

Do older programmers perform as well as young ones? Exploring the intermediate effects of stress and programming experience

Cognition, Technology & Work - There is a widespread perception that older adults are underperformers when compared with younger adults in tasks that involve intense use of technology, such as...     

Stress reactions to computer‐interactive tasks as a function of task structure and individual differences

The resurgence of interest in occupational stress has resulted in an emphasis on identifying work conditions that are potentially causal in generating stress reactions and psychological disorders among workers. Although a considerable knowledge base related to this topic has evolved, relatively little is known regarding the impact of computer technology on incidence of job stress. This issue is especially important for older workers, given the increased use of computers in most occupations, the aging of the workforce, and the changes in cognitive and physiological capacities that occur with increased age. The study reported in this article was concerned with developing a methodology to evaluate stress for computer‐interactive tasks as a function of the mental workload of the task and the age of the individual. Sixty‐five women ranging in age from 25 to 70 years performed three computer‐interactive tasks that varied as a function of information processing complexity and pacing requirements. The methodology encompassed physiological, subjective, and performance measures. Results indicated differences in sensitivity among the measures as a function of task and age. The data also indicated age differences in stress reactions and performance. The findings are discussed in terms of the suitability of computer tasks for older people.     

Modified Alex–Behari model for soil moisture as a function of salinity,texture and frequency

Alex and Behari obtained experimental soil moisture data at microwave frequencies and computed emissivity from these. Following this they suggested an empirical model which provides a good agreement up to a soil moisture value of 25%. Taking into consideration the soil texture, the modified Alex–Behari (MAB) model provides agreement with the available data up to 40%. A non-linear relationship between volumetric soil moisture and emissivity is obtained. The dielectric constant shows an increase with volumetric soil moisture. The dielectric properties of the soil are known to depend on soil moisture content along with other factors like salinity, texture and frequency. In the present investigations the experimental dielectric constant of various types of soils was taken in the frequency range (1.4–18.0 GHz) to fit the modified model in the given range of moisture content. The computed data show that the real part of the dielectric constant decreases and imaginary part increases with soil salinity. It is suggested that the proposed model will be of interest to agricultural scientists, and applicable to remote sensing of salt-affected areas.     

What determines drivers’ speed? A replication of three behavioural adaptation experiments in a single driving simulator study

We conceptually replicated three highly cited experiments on speed adaptation, by measuring drivers’ experienced risk (galvanic skin response; GSR), experienced task difficulty (self-reported task effort; SRTE) and safety margins (time-to-line-crossing; TLC) in a single experiment. The three measures were compared using a nonparametric index that captures the criteria of constancy during self-paced driving and sensitivity during forced-paced driving. In a driving simulator, 24 participants completed two forced-paced and one self-paced run. Each run held four different lane width conditions. Results showed that participants drove faster on wider lanes, thus confirming the expected speed adaptation. None of the three measures offered persuasive evidence for speed adaptation because they failed either the sensitivity criterion (GSR) or the constancy criterion (TLC, SRTE). An additional measure, steering reversal rate, outperformed the other three measures regarding sensitivity and constancy, prompting a further evaluation of the role of control activity in speed adaptation.

Practitioner Summary: Results from a driving simulator experiment suggest that it is not experienced risk, experienced effort or safety margins that govern drivers’ choice of speed. Rather, our findings suggest that steering reversal rate has an explanatory role in speed adaptation.     

Appetizer or main dish? Explaining the use of Facebook news posts as a substitute for other news sources

An increasing number of, especially younger, users use Facebook as their primary source for news about political and societal issues. At the same time, research suggests that Facebook use contributes to societal knowledge gaps. Against this background, we investigate the antecedents of using Facebook as a substitute for other news sources. We argue that exposure to news posts on Facebook increases the feeling of being well-informed, regardless of actual knowledge acquisition. This might lead users, especially those with a low need for cognition (NfC), to use Facebook as a substitute for other news sources. We test these assumptions with an online survey (n = 390) of German Internet users. Results show that the feeling of being well-informed through Facebook is reinforced by the quantity of exposure to news content on Facebook but not by the amount of actually read news posts. The feeling of being informed is an important predictor of using Facebook news as a substitute. Low NfC fosters this effect. It makes the substitution of other news sources more likely—but only for moderate to high levels of feeling well-informed through Facebook. We discuss these results in the light of their societal consequences.     

Online product review as an indicator of users’ degree of innovativeness and product adoption time: a longitudinal analysis of text reviews

Online reviews have become extremely valuable sources of information about products and their customers as electronic commerce continues to proliferate rapidly. Previous research has shown that reviews of a product change and evolve over its life. Identifying and understanding patterns of change in reviews and the forces that shape them is an underexplored topic with substantial potential for predicting and improving the market performance of products. In this study, we analyze review text of nearly 50 products over the course of their lives. Our longitudinal analysis of reviews reveals changes in certain personality-related characteristics of buyers in ways that are consistent with the predictions of product adoption and diffusion theories. The main findings and conclusions still hold when we replicate the same procedure on reviews of a different product category. Accordingly, based on online user-generated content in the form of online reviews, this research introduces a novel empirical method for identifying the product adoption and diffusion stage. Implications of the study for theory, methodology, and practice are discussed.     

What makes a video go viral? An analysis of emotional contagion and Internet memes

What qualities lead some Internet videos to reach millions of viewers while others languish in obscurity? This question has been largely unexamined empirically. We addressed this issue by examining the role of emotional response and video source on the likelihood of spreading an Internet video by validating the emotional response to an Internet video and investigating the underlying mechanisms. Results indicated that individuals reporting strong affective responses to a video reported greater intent to spread the video. In terms of the role of the source, anger-producing videos were more likely to be forwarded but only when the source of the video was an out-group member. These results have implications for emotional contagion, social influence, and online behavior.     

What to do after a data breach? Examining apology and compensation as response strategies for health service providers

Innovative IT-enabled health services promise tremendous benefits for customers and service providers alike. Simultaneously, health services by nature process sensitive customer information, and data breaches have become an everyday phenomenon. The challenge that health service providers face is to find effective recovery strategies after data breaches to retain customer trust and loyalty. We theorize and investigate how two widely applied recovery actions (namely apology and compensation) affect customer reactions after a data breach in the specific context of fitness trackers. Drawing on expectation confirmation theory, we argue that the recovery actions derived from practice, apology, and compensation address the assimilation-contrast model’s tolerance range and, thus, always lead to satisfaction with the recovery strategy, which positively influences customers’ behavior. We employ an experimental investigation and collect data from fitness tracker users during a running event. In the end, we found substantial support for our research model. Health service providers should determine specific customer expectations and align their data breach recovery strategies accordingly.

     

Do we trust the crowd or information system? Effects of personalization and bandwagon cues on users' attitudes and behavioral intentions toward a restaurant recommendation website

Visual interface cues on many websites can influence Internet users' psychology, especially their perceptions about the site as well as its content (Sundar, 2008). Specifically, presence of commonly used interface cues (e.g., personalization, bandwagon cues) can substantially influence users' attitudes and their behavioral intentions toward websites and their content. This study examined the effect of personalization feature and bandwagon cues (i.e., star ratings, reviews) in a restaurant recommendation website, measuring (a) to what extent users positively perceive and plan on revisiting or sharing the site, and (b) to what degree users favored the recommended restaurant and plan to visit them. A 2 (personalization feature: present vs. absent) × 2 (bandwagon cues: high vs. low) between-subjects experiment showed that personalization feature and bandwagon cues increased positive perceptions and their behavioral intentions toward both the website and the recommended restaurant. Moreover, results revealed that users' perceived relevance as well as perceived novelty mediated the effects of interface cues on their attitudinal and behavioral consequences. Further, the impact of the interface cues on user psychology significantly differed as a function of the other cues. Theoretical and practical implications for future research on the effect of interface cues on user psychology are discussed.     

Optimal work–rest cycles for an isometric intermittent gripping task as a function of force,posture and grip span

The aim of this study was to investigate the maximum acceptable contraction frequencies (i.e. work–rest cycles) for an isometric-intermittent handgrip task as a function of grip span, applied force and shoulder posture using psychophysical and physiological approaches. Twelve healthy males served as subjects. The three grip spans investigated were the optimal, 2 cm narrower than the optimal, and 2 cm wider than the optimal. The grip force levels studied were 15% and 30% of maximum voluntary grip force and the two shoulder postures were 25° flexion and 30° abduction. The psychophysical results indicate that subjects work faster with the narrower grip span at 15% of maximum voluntary grip force level in comparison to working with the optimal and the wider spans. However, when the task required 30% of maximum grip force level, the subjects worked faster with the optimal grip span. These findings were supported by the results of electromyography, heart rate, blood pressure and perceived discomfort. The study suggests that grip span of a tool is an important factor to be considered in predicting optimal work–rest cycles for hand grip tasks, and the optimum setting of grip span of the hand-tool depends on the required task force level. That is, the optimality is relative rather than absolute. In addition, it appears that weaker subjects can work at a higher rate than stronger ones at the same relative force level.