Rollover Effects Research Articles

Listening effort mitigates rollover effects on speech-in-noise perception

Increasing the sound intensity may lead to worse speech understanding, especially in noise. This is known as the “Rollover” phenomenon. There is mounting evidence that listening effort plays an important role in challenging listening conditions and can be directly quantified with objective measures such as pupil dilation. However, there is limited understanding of how listening effort relates to rollover in speech understanding. We hypothesized that listening effort plays an essential role in mitigating rollover effects to differential extents across age and hearing status. We recruited across the adult lifespan (N = 50, 20–83 years) with different hearing statuses in acoustic listeners and cochlear implant users to perform a speech discrimination task. Minimal word pairs were presented both in quiet and in 0 dB SNR babble noise, ranging from 35–85 dB SPL. Pupil area was tracked simultaneously with behavioral responses during the task. We found that normal-hearing listeners are fully able to utilize effort contributions to minimize rollover effects between in quiet and in noise conditions, with diminishing benefit as a function of age and increased hearing loss. The results of this project could broadly influence how to design future hearing devices and interventions that maximize hearing abilities for those affected by hearing loss.

Rollover dynamics modelling and analysis of self-propelled combine harvester

This study investigated the rollover phenomenon of a self-propelled combine harvester during short-distance cross-region travel on a road. The mathematical model of the unsteady lateral multi-degree-of-freedom (multi-DOF) motion of the combine harvester was established with consideration to rear wheel steering, front wheel braking, wheel sideslip, and tyre lateral deflection. By carrying out complex kinematics analysis for the entire vehicle and rotational dynamics analysis for the wheels, the mathematical relationships among the lateral deflection angles of the tyres, the kinematic parameters of the combine harvester centroid, the steering angles of the rear wheels, and the speed components of the wheel centroids along their longitudinal directions were derived and used to transform the established mathematical model into a novel form that considers the steering angles and kinematic parameters as unknown quantities. The lateral load transfer ratio (LTR) model of the combine harvester was established to assess the harvester's rollover critical state. Finally, by considering the steering angles of the rear wheels and the braking torque of the front wheels as model inputs, the rollover mechanism and effects of the structural geometry, steering angles, and braking torque on the LTR of the combine harvester were revealed through numerical calculation, and the safety intervals of the parameters were obtained. The results obtained by this study can provide theoretical and technical support for the dynamic design, control, and rollover protection of combine harvesters. • The rear-wheel steering instability analysis method of a combine is proposed. • An unsteady lateral motion model of the combine is established. • Mathematical relationships among the multiple kinematic parameters are established. • The parameter effects and rollover mechanism of the combine are revealed. • Results give a theoretical basis to the anti-rollover design, control and warning.

Protection of structural systems and mechanisms from catastrophic and life-threatening failure caused by unforeseeable events

Structural framing systems and mechanisms designed for normal use rarely possess adequate robustness to withstand the effects of large impacts, blasts and extreme earthquakes that have been experienced in recent times. Robustness is the property of systems that enables them to survive unforeseen or unusual circumstances (Knoll and Vogel, 2009). Queensland University of Technology with industry collaboration is engaged in a program of research that commenced 15 years ago to study the impact of such unforeseeable phenomena and investigate methods of improving robustness and safety with protective mechanisms embedded or designed in structural systems. This paper highlights some of the research pertaining to seismic protection of building structures, rollover protective structures and effects of vehicular impact and blast on key elements in structures that could propagate catastrophic and disproportionate collapse.

Protection of Structural Systems and Mechanisms from Catastrophic and Life-Threatening Failure Caused by Unforeseeable Events

Structural framing systems and mechanisms designed for normal use rarely possess adequate robustness to withstand the effects of large impacts, blasts and extreme earthquakes that have been experienced in recent times. Robustness is the property of systems that enables them to survive unforeseen or unusual circumstances (Knoll & Vogel, 2009). Queensland University of Technology with industry collaboration is engaged in a program of research that commenced 15 years ago to study the impact of such unforeseeable phenomena and investigate methods of improving robustness and safety with protective mechanisms embedded or designed in structural systems. This paper highlights some of the research pertaining to seismic protection of building structures, rollover protective structures and effects of vehicular impact and blast on key elements in structures that could propagate catastrophic and disproportionate collapse.

A task-based model of perceived website complexity

In this study, we propose that perceived website complexity (PWC) is central to understanding how sophisticated features of a website (such as animation, audio, video, and rollover effects) affect ...

Intelligibility of speech in noise at high presentation levels: Effects of hearing loss and frequency region

These experiments examined how high presentation levels influence speech recognition for high- and low-frequency stimuli in noise. Normally hearing (NH) and hearing-impaired (HI) listeners were tested. In Experiment 1, high- and low-frequency bandwidths yielding 70%-correct word recognition in quiet were determined at levels associated with broadband speech at 75 dB SPL. In Experiment 2, broadband and band-limited sentences (based on passbands measured in Experiment 1) were presented at this level in speech-shaped noise filtered to the same frequency bandwidths as targets. Noise levels were adjusted to produce approximately 30%-correct word recognition. Frequency bandwidths and signal-to-noise ratios supporting criterion performance in Experiment 2 were tested at 75, 87.5, and 100 dB SPL in Experiment 3. Performance tended to decrease as levels increased. For NH listeners, this "rollover" effect was greater for high-frequency and broadband materials than for low-frequency stimuli. For HI listeners, the 75- to 87.5-dB increase improved signal audibility for high-frequency stimuli and rollover was not observed. However, the 87.5- to 100-dB increase produced qualitatively similar results for both groups: scores decreased most for high-frequency stimuli and least for low-frequency materials. Predictions of speech intelligibility by quantitative methods such as the Speech Intelligibility Index may be improved if rollover effects are modeled as frequency dependent.

A Task-Based Model of Perceived Website Complexity

In this study, we propose that perceived website complexity (PWC) is central to understanding how sophisticated features of a website (such as animation, audio, video, and rollover effects) affect a visitor's experience at the site. Although previous research suggests that several elements of perceived complexity (e.g., amount of text, animation, graphics, range and consistency of web pages configuring a website, ease of navigating through it, and clarity of hyperlinks) affect important user outcomes, conflicting results yielded by previous research have created an important debate: does complexity enhance or inhibit user experience at a website. In this study, we draw on the task complexity literature to develop a broad and holistic model that examines the antecedents and consequences of PWC. Our results provide two important insights into the relationship between PWC and user outcomes. First, the positive relationship between objective complexity and PWC was moderated by user familiarity. Second, online task goals (goal-directed search and experiential browsing) moderated the relationship between PWC and user satisfaction. Specifically, the relationship between PWC and user satisfaction was negative for goal-directed users and inverted-U for experiential users. The implications of this finding for the practice of website design are discussed.

Development of a web-based graduate-level module courseware

This article presents a survey analysis conducted in and the implementation of a web-based courseware for a graduate-level module on Rapid Response Manufacturing. A courseware website has been developed using HyperText Markup Language, JavaScripts, and Cascading Style Sheets. The website designed is of a hierarchical design. To allow students to navigate easily in this website, a navigation menu that resembled the popular Microsoft Outlook is hence chosen. The website contains course materials, which serve either as introductory materials or pre-class reading materials, and serves to bridge professors and students. The colors scheme and layout used for the website were carefully chosen to achieve a professional look, and the course materials are informative and meaningful. The course materials are presented in an interactive manner using templates created using Macromedia Flash. Using Flash movies, students are able to choose any topic of their choice easily with the click of the mouse. Some animations and mouse rollover effects are also incorporated into the Flash movies for an increased visual experience. The use of dynamic text in Flash movies also greatly improves the way course contents are maintained on the website, allowing the courseware to be easily updated by the lecturers themselves as the materials for the graduate module are updated as technologies in Rapid Response Manufacturing advance. © 2006 Wiley Periodicals, Inc. Comput Appl Eng Educ 14: 90–105, 2006; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20069

Effects of high intensity on recognition of low- and high-frequency speech in noise

For listeners with normal hearing (NH), speech recognition scores often decrease when intensities exceed moderate levels (rollover is observed). It is currently unclear whether the factors leading to rollover in NH listeners also limit performance for hearing-impaired (HI) listeners at high sound levels. This study aimed at clarifying the stimulus conditions most clearly associated with rollover and whether rollover effects are similar for NH listeners and listeners with mild hearing impairment. In Stage 1, NH and HI listeners heard digitally-filtered sentences and adaptive procedures were used to determine high- and low-frequency bandwidths yielding 70%-correct word recognition in quiet at moderate levels. In Stage 2, broadband and band-limited stimuli (based on the high-, and low-frequency passbands measured in quiet in Stage 1) were tested at moderate levels in background noise. Noise levels were varied adaptively to determine signal-to-noise levels supporting 30%-correct recognition. Stimulus conditions leading to criterion performance at moderate presentation levels in Stage 2 were then retested at higher levels in Stage 3. NH listeners showed larger and more consistent rollover effects for high-frequency than for low-frequency or broadband stimuli. The results for HI listeners showed greater variability but also indicated clear rollover effects for high-frequency stimuli at high levels.

Effects of high presentation levels on recognition of low- and high-frequency speech

Speech recognition accuracy decreases when presentation levels are raised above moderate levels. This “rollover” effect at high levels has generally been viewed as a broadband phenomenon, influencing low- and high-frequency processing similarly. In the current study, listeners with normal hearing identified lowpass and highpass sentences at a range of presentation levels to determine whether rollover effects might be greater in either region. Recognition scores showed larger and more consistent decreases at high levels (i.e., greater rollover) for high-frequency speech materials. The results are consistent with both physiological and psychoacoustic data suggesting that cochlear processing shows greater level dependence in basal regions tuned to high frequencies than apical, low-frequency regions. Predictions of speech intelligibility by methods such as the Speech Intelligibility Index [ANSI, 1997] may be improved if the frequency-dependence of rollover is considered.

The Cognitive Psychology of Lottery Gambling: A Theoretical Review.

Despite the current popularity of the UK National, psychologists have tended to neglect lottery play. This review provides a summary of current research findings and outlines the main cognitive theories of gambling as related to non-pathological lottery play. A discussion of various biases and irrational thinking patterns typically found in lottery gambling will be given. These will include the misunderstanding of lottery odds, a susceptibility to the gambler's fallacy and cognitive entrapment, a belief in hot and cold numbers, unrealistic optimism, a belief in personal luck, superstitious thinking, the illusion of control, the erroneous perception of near misses, a susceptibility to prize size and rollover effects, the framing of gambling outcomes and finally, the influence of social factors on lottery play. It is concluded that the psychology of lottery play needs a more unified theory which whilst largely cognitive in emphasis, should also incorporate social motivations such as those inherent in syndicate based lottery play.

Line profiles in coherent forward scattering spectroscopy

Coherent forward scattering (CFS) spectroscopy is a useful tool for element determination. Owing to very different spectral profiles obtained by dichroism and birefringence in addition to the Zeeman hyperfine and isotopic structure, the line profiles of CFS appear much more complicated than those of absorption. The widths and the shapes of line profiles are important with respect to structured atomic and molecular spectral interferences as well as to saturation and roll-over effects. Furthermore, recent developments of atomic resonance monochromators focus special interest on CFS line profiles. Calculations for the CFS D 1 line of sodium based on the complex Voigt function in the range from the predominantly Gaussian to the Lorentzian limit are presented together with high-resolution dye laser measurements as well as integral data obtained with continuum sources.