Hunger neurons drive feeding through a sustained, positive reinforcement signal

PubMed Central

Chen, Yiming; Lin, Yen-Chu; Zimmerman, Christopher A; Essner, Rachel A; Knight, Zachary A

2016-01-01

The neural mechanisms underlying hunger are poorly understood. AgRP neurons are activated by energy deficit and promote voracious food consumption, suggesting these cells may supply the fundamental hunger drive that motivates feeding. However recent in vivo recording experiments revealed that AgRP neurons are inhibited within seconds by the sensory detection of food, raising the question of how these cells can promote feeding at all. Here we resolve this paradox by showing that brief optogenetic stimulation of AgRP neurons before food availability promotes intense appetitive and consummatory behaviors that persist for tens of minutes in the absence of continued AgRP neuron activation. We show that these sustained behavioral responses are mediated by a long-lasting potentiation of the rewarding properties of food and that AgRP neuron activity is positively reinforcing. These findings reveal that hunger neurons drive feeding by transmitting a positive valence signal that triggers a stable transition between behavioral states. DOI: http://dx.doi.org/10.7554/eLife.18640.001 PMID:27554486

Electron bunch energy and phase feed-forward stabilization system for the Mark V RF-linac free-electron laser

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hadmack, M. R.; Kowalczyk, J. M. D.; Lienert, B. R.

2013-06-15

An amplitude and phase compensation system has been developed and tested at the University of Hawai'i for the optimization of the RF drive system to the Mark V free-electron laser. Temporal uniformity of the RF drive is essential to the generation of an electron beam suitable for optimal free-electron laser performance and the operation of an inverse Compton scattering x-ray source. The design of the RF measurement and compensation system is described in detail and the results of RF phase compensation are presented. Performance of the free-electron laser was evaluated by comparing the measured effects of phase compensation with themore » results of a computer simulation. Finally, preliminary results are presented for the effects of amplitude compensation on the performance of the complete system.« less

Optimization of reactive simulated moving bed systems with modulation of feed concentration for production of glycol ether ester.

PubMed

Agrawal, Gaurav; Oh, Jungmin; Sreedhar, Balamurali; Tie, Shan; Donaldson, Megan E; Frank, Timothy C; Schultz, Alfred K; Bommarius, Andreas S; Kawajiri, Yoshiaki

2014-09-19

In this article, we extend the simulated moving bed reactor (SMBR) mode of operation to the production of propylene glycol methyl ether acetate (DOWANOL™ PMA glycol ether) through the esterification of 1-methoxy-2-propanol (DOWANOL™ PM glycol ether) and acetic acid using AMBERLYST™ 15 as a catalyst and adsorbent. In addition, for the first time, we integrate the concept of modulation of the feed concentration (ModiCon) to SMBR operation. The performance of the conventional (constant feed) and ModiCon operation modes of SMBR are analyzed and compared. The SMBR processes are designed using a model based on a multi-objective optimization approach, where a transport dispersive model with a linear driving force for the adsorption rate has been used for modeling the SMBR system. The adsorption equilibrium and kinetics parameters are estimated from the batch and single column injection experiments by the inverse method. The multiple objectives are to maximize the production rate of DOWANOL™ PMA glycol ether, maximize the conversion of the esterification reaction and minimize the consumption of DOWANOL™ PM glycol ether which also acts as the desorbent in the chromatographic separation. It is shown that ModiCon achieves a higher productivity by 12-36% over the conventional operation with higher product purity and recovery. Copyright © 2014 Elsevier B.V. All rights reserved.

A model of the evolution of larval feeding rate in Drosophila driven by conflicting energy demands.

PubMed

Mueller, Laurence D; Barter, Thomas T

2015-02-01

Energy allocation is believed to drive trade-offs in life history evolution. We develop a physiological and genetic model of energy allocation that drives evolution of feeding rate in a well-studied model system. In a variety of stressful environments Drosophila larvae adapt by altering their rate of feeding. Drosophila larvae adapted to high levels of ammonia, urea, and the presence of parasitoids evolve lower feeding rates. Larvae adapted to crowded conditions evolve higher feeding rates. Feeding rates should affect gross food intake, metabolic rates, and efficiency of food utilization. We develop a model of larval net energy intake as a function of feeding rates. We show that when there are toxic compounds in the larval food that require energy for detoxification, larvae can maximize their energy intake by slowing their feeding rates. While the reduction in feeding rates may increase development time and decrease competitive ability, we show that genotypes with lower feeding rates can be favored by natural selection if they have a sufficiently elevated viability in the toxic environment. This work shows how a simple phenotype, larval feeding rates, may be of central importance in adaptation to a wide variety of stressful environments via its role in energy allocation.

Estimation of tool wear compensation during micro-electro-discharge machining of silicon using process simulation

NASA Astrophysics Data System (ADS)

Muralidhara, .; Vasa, Nilesh J.; Singaperumal, M.

2010-02-01

A micro-electro-discharge machine (Micro EDM) was developed incorporating a piezoactuated direct drive tool feed mechanism for micromachining of Silicon using a copper tool. Tool and workpiece materials are removed during Micro EDM process which demand for a tool wear compensation technique to reach the specified depth of machining on the workpiece. An in-situ axial tool wear and machining depth measurement system is developed to investigate axial wear ratio variations with machining depth. Stepwise micromachining experiments on silicon wafer were performed to investigate the variations in the silicon removal and tool wear depths with increase in tool feed. Based on these experimental data, a tool wear compensation method is proposed to reach the desired depth of micromachining on silicon using copper tool. Micromachining experiments are performed with the proposed tool wear compensation method and a maximum workpiece machining depth variation of 6% was observed.

Robust iterative learning contouring controller with disturbance observer for machine tool feed drives.

PubMed

Simba, Kenneth Renny; Bui, Ba Dinh; Msukwa, Mathew Renny; Uchiyama, Naoki

2018-04-01

In feed drive systems, particularly machine tools, a contour error is more significant than the individual axial tracking errors from the view point of enhancing precision in manufacturing and production systems. The contour error must be within the permissible tolerance of given products. In machining complex or sharp-corner products, large contour errors occur mainly owing to discontinuous trajectories and the existence of nonlinear uncertainties. Therefore, it is indispensable to design robust controllers that can enhance the tracking ability of feed drive systems. In this study, an iterative learning contouring controller consisting of a classical Proportional-Derivative (PD) controller and disturbance observer is proposed. The proposed controller was evaluated experimentally by using a typical sharp-corner trajectory, and its performance was compared with that of conventional controllers. The results revealed that the maximum contour error can be reduced by about 37% on average. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

GABAA receptor-expressing neurons promote consumption in Drosophila melanogaster.

PubMed

Cheung, Samantha K; Scott, Kristin

2017-01-01

Feeding decisions are highly plastic and bidirectionally regulated by neurons that either promote or inhibit feeding. In Drosophila melanogaster, recent studies have identified four GABAergic interneurons that act as critical brakes to prevent incessant feeding. These GABAergic neurons may inhibit target neurons that drive consumption. Here, we tested this hypothesis by examining GABA receptors and neurons that promote consumption. We find that Resistance to dieldrin (RDL), a GABAA type receptor, is required for proper control of ingestion. Knockdown of Rdl in a subset of neurons causes overconsumption of tastants. Acute activation of these neurons is sufficient to drive consumption of appetitive substances and non-appetitive substances and acute silencing of these neurons decreases consumption. Taken together, these studies identify GABAA receptor-expressing neurons that promote Drosophila ingestive behavior and provide insight into feeding regulation.

47. VIEW OF FEED LEVEL, CRUSHED OXIDIZED ORE BIN FROM ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

47. VIEW OF FEED LEVEL, CRUSHED OXIDIZED ORE BIN FROM EAST. THE 18 INCH BELT CONVEYOR FEED IS AT CENTER, WITH DRIVE GEAR. THE 16 INCH FINES FEED IS IN THE BACKGROUND AND 18 INCH BELT CONVEYOR DISCHARGE IS SLIGHTLY RIGHT OF CENTER. - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

Evolution of the magma feeding system during a Plinian eruption: The case of Pomici di Avellino eruption of Somma-Vesuvius, Italy

NASA Astrophysics Data System (ADS)

Massaro, S.; Costa, A.; Sulpizio, R.

2018-01-01

The current paradigm for volcanic eruptions is that magma erupts from a deep magma reservoir through a volcanic conduit, typically modelled with fixed rigid geometries such as cylinders. This simplistic view of a volcanic eruption does not account for the complex dynamics that usually characterise a large explosive event. Numerical simulations of magma flow in a conduit combined with volcanological and geological data, allow for the first description of a physics-based model of the feeding system evolution during a sustained phase of an explosive eruption. The method was applied to the Plinian phase of the Pomici di Avellino eruption (PdA, 3945 ±10 cal yr BP) from Somma-Vesuvius (Italy). Information available from volcanology, petrology, and lithology studies was used as input data and as constraints for the model. In particular, Mass Discharge Rates (MDRs) assessed from volcanological methods were used as target values for numerical simulations. The model solutions, which are non-unique, were constrained using geological and volcanological data, such as volume estimates and types of lithic components in the fall deposits. Three stable geometric configurations of the feeding system (described assuming elliptical cross-section of variable dimensions) were assessed for the Eruptive Units 2 and 3 (EU2, EU3), which form the magmatic Plinian phase of PdA eruption. They describe the conduit system geometry at time of deposition of EU2 base, EU2 top, and EU3. A 7-km deep dyke (length 2 a = 200-4 00 m, width 2 b = 10- 12 m), connecting the magma chamber to the surface, characterised the feeding system at the onset of the Plinian phase (EU2 base). The feeding system rapidly evolved into hybrid geometric configuration, with a deeper dyke (length 2 a = 600- 800 m, width 2 b = 50 m) and a shallower cylindrical conduit (diameter D = 50 m, dyke-to-cylinder transition depth ∼2100 m), during the eruption of the EU2 top. The deeper dyke reached the dimensions of 2 a = 2000 m and 2 b = 60 m at EU3 peak MDR, when the shallower cylinder had enlarged to a diameter of 60 m and a transition depth of 3000 m. The changes in feeding system geometry indicate a partitioning of the driving pressure of the eruption, which affected both magma movement to the surface and dyke growth. This implies that a significant portion of the magma injected from the magma chamber filled the enlarging dyke before it erupted to the surface. In this model, the lower dyke acted as a sort of magma "capacitor" in which the magma was stored briefly before accelerating to the cylindrical conduit and erupting. The capacitor effect of the lower dyke implies longer times of transit for the erupting magma, which also underwent several steps of decompression. On the other hand, the decompression of magma within the capacitor provided the driving pressure to maintain the flow into the upper cylindrical conduit, even as the base of the dyke started to close due to the drop in driving pressure from progressive emptying of the magma chamber. The shallower cylindrical conduit was shaped through the erosion of conduit wall rocks at and above the fragmentation level. Using the lithic volume and duration of EU3, the erosion rate of shallower cylindrical conduit was calculated at ∼5 × 103 m3/s. The outcomes of this work represent an important baseline for further petrologic and geophysical studies devoted to the comprehension of processes driving volcanic eruptions.

Effectiveness evaluation of simulative workshops for newly licensed drivers.

PubMed

Rosenbloom, Tova; Eldror, Ehud

2014-02-01

The current study set to examine the effects of simulator use in driving instruction on newly licensed drivers, comparing the road safety knowledge and reported intended behavior, as well as the actual driving performance of new drivers. Participants consisted of 280 newly licensed driver, of which 140 whose drivers license training included additional simulator-based lessons, and 140 drivers whose training precluded simulator-based lessons. All drivers answered questionnaires pertaining to their intended safe driving behaviors (according to Ajzen's (2000) theory of planned behavior), and to their traffic safety knowledge. Of the initial sample, 40 drivers received actual driving performance evaluation by an expert driving instructor, as well as by in-vehicle data recorders (IVDRs). We assumed that safer drivers report safer driving intentions, demonstrate greater traffic safety knowledge, evaluated as safer drivers by the driving instructor, and display lower and stable driving parameters on the IVDRs. We hypothesized that theoretical driving studies combined with practical training on simulators will elevate the safety level of novices driving. Hierarchical regression analyses on driving intentions indicated that drivers who did not receive simulator-based lessons demonstrated safer driving intentions compared to drivers who received simulator-based lessons. This pattern possibly indicating the drivers who received simulator-based lessons felt more confident in their driving abilities compared to drivers who did not receive simulated training. No significant difference was found in traffic safety knowledge, or in the evaluation of the expert driving instructor. IDVR data comparisons indicated drivers who received simulator-based lessons braked more often and were less prone to headway events, suggesting a more responsive driving style. These findings do not point to any significant advantage or disadvantage of the current simulator-based driving training over other driving training methods. Copyright © 2013 Elsevier Ltd. All rights reserved.

Feed-forward and reciprocal inhibition for gain and phase timing control in a computational model of repetitive cough

PubMed Central

Morris, Kendall F.; Segers, Lauren S.; Poliacek, Ivan; Rose, Melanie J.; Lindsey, Bruce G.; Davenport, Paul W.; Howland, Dena R.; Bolser, Donald C.

2016-01-01

We investigated the hypothesis, motivated in part by a coordinated computational cough network model, that second-order neurons in the nucleus tractus solitarius (NTS) act as a filter and shape afferent input to the respiratory network during the production of cough. In vivo experiments were conducted on anesthetized spontaneously breathing cats. Cough was elicited by mechanical stimulation of the intrathoracic airways. Electromyograms of the parasternal (inspiratory) and rectus abdominis (expiratory) muscles and esophageal pressure were recorded. In vivo data revealed that expiratory motor drive during bouts of repetitive coughs is variable: peak expulsive amplitude increases from the first cough, peaks about the eighth or ninth cough, and then decreases through the remainder of the bout. Model simulations indicated that feed-forward inhibition of a single second-order neuron population is not sufficient to account for this dynamic feature of a repetitive cough bout. When a single second-order population was split into two subpopulations (inspiratory and expiratory), the resultant model produced simulated expiratory motor bursts that were comparable to in vivo data. However, expiratory phase durations during these simulations of repetitive coughing had less variance than those in vivo. Simulations in which reciprocal inhibitory processes between inspiratory-decrementing and expiratory-augmenting-late neurons were introduced exhibited increased variance in the expiratory phase durations. These results support the prediction that serial and parallel processing of airway afferent signals in the NTS play a role in generation of the motor pattern for cough. PMID:27283917

Utah traffic lab driving simulator : user manual and flex lanes scenario development.

DOT National Transportation Integrated Search

2012-06-01

This report describes the University of Utah Traffic Lab (UTL) driving simulator, and a scenario development for Flex Lanes driving simulation. The first part describes the driving simulator in details. At the time of installation, the UTL driving si...

Utah Traffic Lab Driving Simulator : User Manual and Flex Lanes Scenario Development

DOT National Transportation Integrated Search

2012-06-01

This report describes the University of Utah Traffic Lab (UTL) driving simulator, and a scenario development for Flex Lanes driving simulation. The first part describes the driving simulator in details. At the time of installation, the UTL driving si...

Comparing treatment effects of oral THC on simulated and on-the-road driving performance: testing the validity of driving simulator drug research.

PubMed

Veldstra, J L; Bosker, W M; de Waard, D; Ramaekers, J G; Brookhuis, K A

2015-08-01

The driving simulator provides a safe and controlled environment for testing driving behaviour efficiently. The question is whether it is sensitive to detect drug-induced effects. The primary aim of the current study was to investigate the sensitivity of the driving simulator for detecting drug effects. As a case in point, we investigated the dose-related effects of oral ∆(9)-tetrahydrocannabinol (THC), i.e. dronabinol, on simulator and on-the-road driving performance in equally demanding driving tasks. Twenty-four experienced driver participants were treated with dronabinol (Marinol®; 10 and 20 mg) and placebo. Dose-related effects of the drug on the ability to keep a vehicle in lane (weaving) and to follow the speed changes of a lead car (car following) were compared within subjects for on-the-road versus in-simulator driving. Additionally, the outcomes of equivalence testing to alcohol-induced effects were investigated. Treatment effects found on weaving when driving in the simulator were comparable to treatment effects found when driving on the road. The effect after 10 mg dronabinol was however less strong in the simulator than on the road and inter-individual variance seemed higher in the simulator. There was, however, a differential treatment effect of dronabinol on reactions to speed changes of a lead car (car following) when driving on the road versus when driving in the simulator. The driving simulator was proven to be sensitive for demonstrating dronabinol-induced effects particularly at higher doses. Treatment effects of dronabinol on weaving were comparable with driving on the road but inter-individual variability seemed higher in the simulator than on the road which may have potential effects on the clinical inferences made from simulator driving. Car following on the road and in the simulator were, however, not comparable.

Defense.gov Special Report: Feds Feed Families

Science.gov Websites

Department of Defense Submit Search Feds Feed Families: DOD Delivers - Supporting our Fellow Americans - Food Feed Families Food Drive campaign is now under way. Department of Defense employees nationwide will step up to meet this challenge by gathering 1.5 million pounds of food for families in need this summer

Driving assessment and rehabilitation using a driving simulator in individuals with traumatic brain injury: A scoping review.

PubMed

Imhoff, Sarah; Lavallière, Martin; Teasdale, Normand; Fait, Philippe

2016-06-30

Due to the heterogeneity of the lesion following a traumatic brain injury (TBI) and the complexity of the driving task, driving assessment and rehabilitation in TBI individuals is challenging. Conventional driving assessment (on-road and in-clinic evaluations) has failed demonstrating effectiveness to assess fitness to drive in TBI individuals. We aimed to determine if driving simulators represent an interesting opportunity in assessing and rehabilitating driving skills in TBI individuals. We searched PubMed, CINAHL and Cochrane library databases between 27-02-2014 and 08-04-2014 for articles published since 2000 with the contents of simulator driving assessment and rehabilitation. Out of 488, eight articles with the subject of simulator driving assessment and two with the subject of simulator driving rehabilitation in individuals with TBI were reviewed. Driving simulators represent a promising avenue for the assessment and rehabilitation of driving skills in TBI individuals as it allows control of stimuli in a safe, challenging and ecologically valid environment and offer the opportunity to measure and record driving performance. Additional studies, however, are needed to document strengths and limitations of this method.

Text messaging during simulated driving.

PubMed

Drews, Frank A; Yazdani, Hina; Godfrey, Celeste N; Cooper, Joel M; Strayer, David L

2009-10-01

This research aims to identify the impact of text messaging on simulated driving performance. In the past decade, a number of on-road, epidemiological, and simulator-based studies reported the negative impact of talking on a cell phone on driving behavior. However, the impact of text messaging on simulated driving performance is still not fully understood. Forty participants engaged in both a single task (driving) and a dual task (driving and text messaging) in a high-fidelity driving simulator. Analysis of driving performance revealed that participants in the dual-task condition responded more slowly to the onset of braking lights and showed impairments in forward and lateral control compared with a driving-only condition. Moreover, text-messaging drivers were involved in more crashes than drivers not engaged in text messaging. Text messaging while driving has a negative impact on simulated driving performance. This negative impact appears to exceed the impact of conversing on a cell phone while driving. The results increase our understanding of driver distraction and have potential implications for public safety and device development.

The use of adaptation to reduce simulator sickness in driving assessment and research.

PubMed

Domeyer, Joshua E; Cassavaugh, Nicholas D; Backs, Richard W

2013-04-01

The technical advancement of driving simulators has decreased their cost and increased both their accuracy and fidelity. This makes them a useful tool for examining driving behavior in risky or unique situations. With the approaching increase of older licensed drivers due to aging of the baby boomers, driving simulators will be important for conducting driving research and evaluations for older adults. With these simulator technologies, some people may experience significant effects of a unique form of motion sickness, known as simulator sickness. These effects may be more pronounced in older adults. The present study examined the feasibility of an intervention to attenuate symptoms of simulator sickness in drivers participating in a study of a driving evaluation protocol. Prior to beginning the experiment, the experimental groups did not differ in subjective simulator sickness scores as indicated by Revised Simulator Sickness Questionnaire scores (all p>0.5). Participants who experienced a two-day delay between an initial acclimation to the driving simulator and the driving session experienced fewer simulator sickness symptoms as indicated by RSSQ total severity scores than participants who did not receive a two-day delay (F(1,88)=4.54, p=.036, partial η(2)=.049). These findings have implications for improving client well-being and potentially increasing acceptance of driving simulation for driving evaluations and for driving safety research. Copyright © 2013 Elsevier Ltd. All rights reserved.

The drive-wise project: driving simulator training increases real driving performance in healthy older drivers

PubMed Central

Casutt, Gianclaudio; Theill, Nathan; Martin, Mike; Keller, Martin; Jäncke, Lutz

2014-01-01

Background: Age-related cognitive decline is often associated with unsafe driving behavior. We hypothesized that 10 active training sessions in a driving simulator increase cognitive and on-road driving performance. In addition, driving simulator training should outperform cognitive training. Methods: Ninety-one healthy active drivers (62–87 years) were randomly assigned to one of three groups: (1) a driving simulator training group, (2) an attention training group (vigilance and selective attention), or (3) a control group. The main outcome variables were on-road driving and cognitive performance. Seventy-seven participants (85%) completed the training and were included in the analyses. Training gains were analyzed using a multiple regression analysis with planned orthogonal comparisons. Results: The driving simulator-training group showed an improvement in on-road driving performance compared to the attention-training group. In addition, both training groups increased cognitive performance compared to the control group. Conclusion: Driving simulator training offers the potential to enhance driving skills in older drivers. Compared to the attention training, the simulator training seems to be a more powerful program for increasing older drivers' safety on the road. PMID:24860497

Assessing the driving performance of older adult drivers: on-road versus simulated driving.

PubMed

Lee, Hoe C; Cameron, Don; Lee, Andy H

2003-09-01

To validate a laboratory-based driving simulator in measuring on-road driving performance, 129 older adult drivers were assessed with both the simulator and an on-road test. The driving performance of the participants was gauged by appropriate and reliable age-specific assessment criteria, which were found to be negatively correlated with age. Using principal component analysis, two performance indices were developed from the criteria to represent the overall performance in simulated driving and the on-road assessment. There was significant positive association between the two indices, with the simulated driving performance index explaining over two-thirds of the variability of the on-road driving performance index, after adjustment for age and gender of the drivers. The results supported the validity of the driving simulator and it is a safer and more economical method than the on-road testing to assess the driving performance of older adult drivers.

Development of an advanced mobile base for personal mobility and manipulation appliance generation II robotic wheelchair.

PubMed

Wang, Hongwu; Candiotti, Jorge; Shino, Motoki; Chung, Cheng-Shiu; Grindle, Garrett G; Ding, Dan; Cooper, Rory A

2013-07-01

This paper describes the development of a mobile base for the Personal Mobility and Manipulation Appliance Generation II (PerMMA Gen II robotic wheelchair), an obstacle-climbing wheelchair able to move in structured and unstructured environments, and to climb over curbs as high as 8 inches. The mechanical, electrical, and software systems of the mobile base are presented in detail, and similar devices such as the iBOT mobility system, TopChair, and 6X6 Explorer are described. The mobile base of PerMMA Gen II has two operating modes: "advanced driving mode" on flat and uneven terrain, and "automatic climbing mode" during stair climbing. The different operating modes are triggered either by local and dynamic conditions or by external commands from users. A step-climbing sequence, up to 0.2 m, is under development and to be evaluated via simulation. The mathematical model of the mobile base is introduced. A feedback and a feed-forward controller have been developed to maintain the posture of the passenger when driving over uneven surfaces or slopes. The effectiveness of the controller has been evaluated by simulation using the open dynamics engine tool. Future work for PerMMA Gen II mobile base is implementation of the simulation and control on a real system and evaluation of the system via further experimental tests.

Development of an advanced mobile base for personal mobility and manipulation appliance generation II robotic wheelchair

PubMed Central

Wang, Hongwu; Candiotti, Jorge; Shino, Motoki; Chung, Cheng-Shiu; Grindle, Garrett G.; Ding, Dan; Cooper, Rory A.

2013-01-01

Background This paper describes the development of a mobile base for the Personal Mobility and Manipulation Appliance Generation II (PerMMA Gen II robotic wheelchair), an obstacle-climbing wheelchair able to move in structured and unstructured environments, and to climb over curbs as high as 8 inches. The mechanical, electrical, and software systems of the mobile base are presented in detail, and similar devices such as the iBOT mobility system, TopChair, and 6X6 Explorer are described. Findings The mobile base of PerMMA Gen II has two operating modes: “advanced driving mode” on flat and uneven terrain, and “automatic climbing mode” during stair climbing. The different operating modes are triggered either by local and dynamic conditions or by external commands from users. A step-climbing sequence, up to 0.2 m, is under development and to be evaluated via simulation. The mathematical model of the mobile base is introduced. A feedback and a feed-forward controller have been developed to maintain the posture of the passenger when driving over uneven surfaces or slopes. The effectiveness of the controller has been evaluated by simulation using the open dynamics engine tool. Conclusion Future work for PerMMA Gen II mobile base is implementation of the simulation and control on a real system and evaluation of the system via further experimental tests. PMID:23820149

Accurate electrical prediction of memory array through SEM-based edge-contour extraction using SPICE simulation

NASA Astrophysics Data System (ADS)

Shauly, Eitan; Rotstein, Israel; Peltinov, Ram; Latinski, Sergei; Adan, Ofer; Levi, Shimon; Menadeva, Ovadya

2009-03-01

The continues transistors scaling efforts, for smaller devices, similar (or larger) drive current/um and faster devices, increase the challenge to predict and to control the transistor off-state current. Typically, electrical simulators like SPICE, are using the design intent (as-drawn GDS data). At more sophisticated cases, the simulators are fed with the pattern after lithography and etch process simulations. As the importance of electrical simulation accuracy is increasing and leakage is becoming more dominant, there is a need to feed these simulators, with more accurate information extracted from physical on-silicon transistors. Our methodology to predict changes in device performances due to systematic lithography and etch effects was used in this paper. In general, the methodology consists on using the OPCCmaxTM for systematic Edge-Contour-Extraction (ECE) from transistors, taking along the manufacturing and includes any image distortions like line-end shortening, corner rounding and line-edge roughness. These measurements are used for SPICE modeling. Possible application of this new metrology is to provide a-head of time, physical and electrical statistical data improving time to market. In this work, we applied our methodology to analyze a small and large array's of 2.14um2 6T-SRAM, manufactured using Tower Standard Logic for General Purposes Platform. 4 out of the 6 transistors used "U-Shape AA", known to have higher variability. The predicted electrical performances of the transistors drive current and leakage current, in terms of nominal values and variability are presented. We also used the methodology to analyze an entire SRAM Block array. Study of an isolation leakage and variability are presented.

Instability Coupling Experiments*

NASA Astrophysics Data System (ADS)

Chrien, R. E.; Hoffman, N. M.; Magelssen, G. R.; Schappert, G. T.; Smitherman, D. P.

1996-11-01

The coupling of Richtmyer-Meshkov (RM) and ablative Rayleigh-Taylor (ART) instabilities is being studied with indirectly-driven planar foil experiments on the Nova laser at Livermore. The foil is attached to a 1.6-mm-diameter, 2.75-mm-long Au hohlraum driven by a 2.2-ns long, 1:5-contrast-ratio shaped laser pulse. A shock is generated in 35-μm or 86-μm thick Al foils with a 50-μm-wavelength, 4-μm-amplitude sinusoidal perturbation on its rear surface. In some experiments, the perturbation is applied to a 10-μm Be layer on the Al. A RM instability develops when the shock encounters the perturbed surface. The flow field of the RM instability can ``feed out'' to the ablation surface of the foil and provide the seed for ART perturbation growth. Face-on and side-on x-radiography are used to observe areal density perturbations in the foil. For the 86-μm foil, the perturbation arrives at the ablation surface while the hohlraum drive is dropping and the data are consistent with RM instability alone. For the 35-μm foil, the perturbation feeds out while the hohlraum drive is close to its peak and the data appear to show strong ART perturbation growth. Comparisons with LASNEX simulations will be presented. *This work supported under USDOE contract W-7405-ENG-36.

Correspondence between Simulator and On-Road Drive Performance: Implications for Assessment of Driving Safety.

PubMed

Aksan, Nazan; Hacker, Sarah D; Sager, Lauren; Dawson, Jeffrey; Anderson, Steven; Rizzo, Matthew

2016-03-01

Forty-two younger (Mean age = 35) and 37 older drivers (Mean age = 77) completed four similar simulated drives. In addition, 32 younger and 30 older drivers completed a standard on-road drive in an instrumented vehicle. Performance in the simulated drives was evaluated using both electronic drive data and video-review of errors. Safety errors during the on-road drive were evaluated by a certified driving instructor blind to simulator performance, using state Department of Transportation criteria. We examined the degree of convergence in performance across the two platforms on various driving tasks including lane change, lane keeping, speed control, stopping, turns, and overall performance. Differences based on age group indicated a pattern of strong relative validity for simulator measures. However, relative rank-order in specific metrics of performance suggested a pattern of moderate relative validity. The findings have implications for the use of simulators in assessments of driving safety as well as its use in training and/or rehabilitation settings.

Correspondence between Simulator and On-Road Drive Performance: Implications for Assessment of Driving Safety

PubMed Central

Aksan, Nazan; Hacker, Sarah D.; Sager, Lauren; Dawson, Jeffrey; Anderson, Steven; Rizzo, Matthew

2017-01-01

Forty-two younger (Mean age = 35) and 37 older drivers (Mean age = 77) completed four similar simulated drives. In addition, 32 younger and 30 older drivers completed a standard on-road drive in an instrumented vehicle. Performance in the simulated drives was evaluated using both electronic drive data and video-review of errors. Safety errors during the on-road drive were evaluated by a certified driving instructor blind to simulator performance, using state Department of Transportation criteria. We examined the degree of convergence in performance across the two platforms on various driving tasks including lane change, lane keeping, speed control, stopping, turns, and overall performance. Differences based on age group indicated a pattern of strong relative validity for simulator measures. However, relative rank-order in specific metrics of performance suggested a pattern of moderate relative validity. The findings have implications for the use of simulators in assessments of driving safety as well as its use in training and/or rehabilitation settings. PMID:28649572

Modeling of Driver Steering Operations in Lateral Wind Disturbances toward Driver Assistance System

NASA Astrophysics Data System (ADS)

Kurata, Yoshinori; Wada, Takahiro; Kamiji, Norimasa; Doi, Shun'ichi

Disturbances decrease vehicle stability and increase driver's mental and physical workload. Especially unexpected disturbances such as lateral winds have severe effect on vehicle stability and driver's workload. This study aims at building a driver model of steering operations in lateral wind toward developing effective driver assistance system. First, the relationship between the driver's lateral motion and its reactive quick steering behavior is investigated using driving simulator with lateral 1dof motion. In the experiments, four different wind patterns are displayed by the simulator. As the results, strong correlation was found between the driver's head lateral jerk by the lateral disturbance and the angular acceleration of the steering wheel. Then, we build a mathematical model of driver's steering model from lateral disturbance input to steering torque of the reactive quick feed-forward steering based on the experimental results. Finally, validity of the proposed model is shown by comparing the steering torque of experimental results and that of simulation results.

The utility of the AusEd driving simulator in the clinical assessment of driver fatigue.

PubMed

Desai, Anup V; Wilsmore, Brad; Bartlett, Delwyn J; Unger, Gunnar; Constable, Ben; Joffe, David; Grunstein, Ronald R

2007-08-01

Several driving simulators have been developed which range in complexity from PC based driving tasks to advanced "real world" simulators. The AusEd driving simulator is a PC based task, which was designed to be conducive to and test for driver fatigue. This paper describes the AusEd driving simulator in detail, including the technical requirements, hardware, screen and file outputs, and analysis software. Some aspects of the test are standardized, while others can be modified to suit the experimental situation. The AusEd driving simulator is sensitive to performance decrement from driver fatigue in the laboratory setting, potentially making it useful as a laboratory or office based test for driver fatigue risk management. However, more research is still needed to correlate laboratory based simulator performance with real world driving performance and outcomes.

Feed-forward and reciprocal inhibition for gain and phase timing control in a computational model of repetitive cough.

PubMed

Pitts, Teresa; Morris, Kendall F; Segers, Lauren S; Poliacek, Ivan; Rose, Melanie J; Lindsey, Bruce G; Davenport, Paul W; Howland, Dena R; Bolser, Donald C

2016-07-01

We investigated the hypothesis, motivated in part by a coordinated computational cough network model, that second-order neurons in the nucleus tractus solitarius (NTS) act as a filter and shape afferent input to the respiratory network during the production of cough. In vivo experiments were conducted on anesthetized spontaneously breathing cats. Cough was elicited by mechanical stimulation of the intrathoracic airways. Electromyograms of the parasternal (inspiratory) and rectus abdominis (expiratory) muscles and esophageal pressure were recorded. In vivo data revealed that expiratory motor drive during bouts of repetitive coughs is variable: peak expulsive amplitude increases from the first cough, peaks about the eighth or ninth cough, and then decreases through the remainder of the bout. Model simulations indicated that feed-forward inhibition of a single second-order neuron population is not sufficient to account for this dynamic feature of a repetitive cough bout. When a single second-order population was split into two subpopulations (inspiratory and expiratory), the resultant model produced simulated expiratory motor bursts that were comparable to in vivo data. However, expiratory phase durations during these simulations of repetitive coughing had less variance than those in vivo. Simulations in which reciprocal inhibitory processes between inspiratory-decrementing and expiratory-augmenting-late neurons were introduced exhibited increased variance in the expiratory phase durations. These results support the prediction that serial and parallel processing of airway afferent signals in the NTS play a role in generation of the motor pattern for cough. Copyright © 2016 the American Physiological Society.

Anxiety, Sedation, and Simulated Driving in Binge Drinkers

PubMed Central

Aston, Elizabeth R.; Shannon, Erin E.; Liguori, Anthony

2014-01-01

The current study evaluated the relationships among trait anxiety, subjective response to alcohol, and simulated driving following a simulated alcohol binge. Sixty drinkers with a binge history completed the State Trait Anxiety Inventory (STAI), the Alcohol Use Questionnaire, and subsequently completed a driving simulation. Participants were then administered 0.2 g/kg ethanol at 30 minute intervals (cumulative dose 0.8 g/kg). Following alcohol consumption, the Biphasic Alcohol Effects Scale (BAES) and visual analog scales of subjective impairment and driving confidence were administered, after which simulated driving was re-assessed. Due to the emphasis on simulated driving after drinking in the current study, subjective response to alcohol (i.e., self-reported sedation, stimulation, impairment, and confidence in driving ability) was assessed once following alcohol consumption, as this is the time when drinkers tend to make decisions regarding legal driving ability. Alcohol increased driving speed, speeding tickets, and collisions. Sedation following alcohol predicted increased subjective impairment and decreased driving confidence. Subjective impairment was not predicted by sensitivity to stimulation or trait anxiety. High trait anxiety predicted low driving confidence after drinking and this relationship was mediated by sedation. Increased speed after alcohol was predicted by sedation, but not by trait anxiety or stimulation. Anxiety, combined with the sedating effects of alcohol, may indicate when consumption should cease. However, once driving is initiated, sensitivity to sedation following alcohol consumption is positively related to simulated driving speed. PMID:24955664

A malaria transmission-directed model of mosquito life cycle and ecology

PubMed Central

2011-01-01

Background Malaria is a major public health issue in much of the world, and the mosquito vectors which drive transmission are key targets for interventions. Mathematical models for planning malaria eradication benefit from detailed representations of local mosquito populations, their natural dynamics and their response to campaign pressures. Methods A new model is presented for mosquito population dynamics, effects of weather, and impacts of multiple simultaneous interventions. This model is then embedded in a large-scale individual-based simulation and results for local elimination of malaria are discussed. Mosquito population behaviours, such as anthropophily and indoor feeding, are included to study their effect upon the efficacy of vector control-based elimination campaigns. Results Results for vector control tools, such as bed nets, indoor spraying, larval control and space spraying, both alone and in combination, are displayed for a single-location simulation with vector species and seasonality characteristic of central Tanzania, varying baseline transmission intensity and vector bionomics. The sensitivities to habitat type, anthropophily, indoor feeding, and baseline transmission intensity are explored. Conclusions The ability to model a spectrum of local vector species with different ecologies and behaviours allows local customization of packages of interventions and exploration of the effect of proposed new tools. PMID:21999664

Predictive validity of driving-simulator assessments following traumatic brain injury: a preliminary study.

PubMed

Lew, Henry L; Poole, John H; Lee, Eun Ha; Jaffe, David L; Huang, Hsiu-Chen; Brodd, Edward

2005-03-01

To evaluate whether driving simulator and road test evaluations can predict long-term driving performance, we conducted a prospective study on 11 patients with moderate to severe traumatic brain injury. Sixteen healthy subjects were also tested to provide normative values on the simulator at baseline. At their initial evaluation (time-1), subjects' driving skills were measured during a 30-minute simulator trial using an automated 12-measure Simulator Performance Index (SPI), while a trained observer also rated their performance using a Driving Performance Inventory (DPI). In addition, patients were evaluated on the road by a certified driving evaluator. Ten months later (time-2), family members observed patients driving for at least 3 hours over 4 weeks and rated their driving performance using the DPI. At time-1, patients were significantly impaired on automated SPI measures of driving skill, including: speed and steering control, accidents, and vigilance to a divided-attention task. These simulator indices significantly predicted the following aspects of observed driving performance at time-2: handling of automobile controls, regulation of vehicle speed and direction, higher-order judgment and self-control, as well as a trend-level association with car accidents. Automated measures of simulator skill (SPI) were more sensitive and accurate than observational measures of simulator skill (DPI) in predicting actual driving performance. To our surprise, the road test results at time-1 showed no significant relation to driving performance at time-2. Simulator-based assessment of patients with brain injuries can provide ecologically valid measures that, in some cases, may be more sensitive than a traditional road test as predictors of long-term driving performance in the community.

Preliminary report of the Hepatic Encephalopathy Assessment Driving Simulator (HEADS) score.

PubMed

Baskin-Bey, Edwina S; Stewart, Charmaine A; Mitchell, Mary M; Bida, John P; Rosenthal, Theodore J; Nyberg, Scott L

2008-01-01

Audiovisual simulations of real-life driving (ie, driving simulators) have been used to assess neurologic dysfunction in a variety of medical applications. However, the use of simulated driving to assess neurologic impairment in the setting of liver disease (ie, hepatic encephalopathy) is limited. The aim of this analysis was to develop a scoring system based on simulated driving performance to assess mild cognitive impairment in cirrhotic patients with hepatic encephalopathy. This preliminary analysis was conducted as part of the Hepatic Encephalopathy Assessment Driving Simulator (HEADS) pilot study. Cirrhotic volunteers initially underwent a battery of neuropsychological tests to identify those cirrhotic patients with mild cognitive impairment. Performance during an audiovisually simulated course of on-road driving was then compared between mildly impaired cirrhotic patients and healthy volunteers. A scoring system was developed to quantify the likelihood of cognitive impairment on the basis of data from the simulated on-road driving. Mildly impaired cirrhotic patients performed below the level of healthy volunteers on the driving simulator. Univariate logistic regression and correlation models indicated that several driving simulator variables were significant predictors of cognitive impairment. Five variables (run time, total map performance, number of collisions, visual divided attention response, and average lane position) were incorporated into a quantitative model, the HEADS scoring system. The HEADS score (0-9 points) showed a strong correlation with cognitive impairment as measured by area under the receiver-operator curve (.89). The HEADS system appears to be a promising new tool for the assessment of mild hepatic encephalopathy.

Feelings about food: the ventral tegmental area in food reward and emotional eating.

PubMed

Meye, Frank J; Adan, Roger A H

2014-01-01

Overconsumption of high caloric food plays an important role in the etiology of obesity. Several factors drive such hedonic feeding. High caloric food is often palatable. In addition, when an individual is sated, stress and food-related cues can serve as potent feeding triggers. A better understanding of the neurobiological underpinnings of food palatability and environmentally triggered overconsumption would aid the development of new treatment strategies. In the current review we address the pivotal role of the mesolimbic dopamine reward system in the drive towards high caloric palatable food and its relation to stress- and cue-induced feeding. We also discuss how this system may be affected by both established and potential anti-obesity drug targets. Copyright © 2013 Elsevier Ltd. All rights reserved.

Economic evaluation of alternative crossbreeding systems involving four breeds of swine. I. The simulation model.

PubMed

McLaren, D G; Buchanan, D S; Williams, J E

1987-10-01

A static, deterministic computer model, programmed in Microsoft Basic for IBM PC and Apple Macintosh computers, was developed to calculate production efficiency (cost per kg of product) for nine alternative types of crossbreeding system involving four breeds of swine. The model simulates efficiencies for four purebred and 60 alternative two-, three- and four-breed rotation, rotaterminal, backcross and static cross systems. Crossbreeding systems were defined as including all purebred, crossbred and commercial matings necessary to maintain a total of 10,000 farrowings. Driving variables for the model are mean conception rate at first service and for an 8-wk breeding season, litter size born, preweaning survival rate, postweaning average daily gain, feed-to-gain ratio and carcass backfat. Predictions are computed using breed direct genetic and maternal effects for the four breeds, plus individual, maternal and paternal specific heterosis values, input by the user. Inputs required to calculate the number of females farrowing in each sub-system include the proportion of males and females replaced each breeding cycle in purebred and crossbred populations, the proportion of male and female offspring in seedstock herds that become breeding animals, and the number of females per boar. Inputs required to calculate the efficiency of terminal production (cost-to-product ratio) for each sub-system include breeding herd feed intake, gilt development costs, feed costs and labor and overhead costs. Crossbreeding system efficiency is calculated as the weighted average of sub-system cost-to-product ratio values, weighting by the number of females farrowing in each sub-system.

Pneu-Scan - A novel, lightweight two-axis telemetry tracking system

NASA Astrophysics Data System (ADS)

Sullivan, A.

The development of Pneu-Scan, a conically scanning tracking antenna feed for telemetry applications, is described. Pneu-Scan has the advantage of being pneumatically driven, thereby eliminating the need for a heavy electric drive motor. Air from the dehydrator/pressurizer system is used to drive the Pneu-Scan pedestal at a scan speed which is proportional to the continuously varying pressure. The S-band tracking feed of the Pneu-Scan is less than five inches in diameter and is considerably lighter than single-channel monopulse (SCM) feeds. Aperture blocking of Pneu-Scan is more than two times smaller than conventional SCM designs. The antenna reflector of the Pneu-Scan system is a lightweight 5-foot graphite-epoxy parabolical reflector positioned by an elevator-over-azimuth pedestal. The elevation assembly is surrounded by an inflatable rotodome which rotates with azimuth. The rotating sphere was designed to have a minimum wind-induced torque, thereby minimizing the required drive power. The weight of the entire system is less than 135 pounds. The principle characteristics of the Pneu-Scan system are summarized in a table.

Both texting and eating are associated with impaired simulated driving performance.

PubMed

Alosco, Michael L; Spitznagel, Mary Beth; Fischer, Kimberly Hall; Miller, Lindsay A; Pillai, Vivek; Hughes, Joel; Gunstad, John

2012-09-01

Distracted driving is a known contributor to traffic accidents, and many states have banned texting while driving. However, little is known about the potential accident risk of other common activities while driving, such as eating. The objective of the current study was to examine the adverse impact of eating/drinking behavior relative to texting and nondistracted behaviors on a simulated driving task. A total of 186 participants were recruited from undergraduate psychology courses over 2 semesters at Kent State University. We utilized the Kent Multidimensional Assessment Driving Simulation (K-MADS) to compare simulated driving performance among participants randomly assigned to texting (N = 45), eating (N = 45), and control (N = 96) conditions. Multivariate analyses of variance (MANOVA) were conducted to examine between-group differences on simulated driving indices. MANOVA analyses indicated that groups differed in simulated driving performance, F(14, 366) = 7.70, P < .001. Both texting and eating produced impaired driving performance relative to controls, though these behaviors had approximately equal effect. Specifically, both texting and eating groups had more collisions, pedestrian strikes, and center line crossings than controls. In addition, the texting group had more road edge excursions than either eating or control participants and the eating group missed more stop signs than controls. These findings suggest that both texting and eating are associated with poorer simulated driving performance. Future work is needed to determine whether these findings generalize to real-world driving and the development of strategies to reduce distracted driving.

Exploring travelers' behavior in response to dynamic message signs (DMS) using a driving simulator.

DOT National Transportation Integrated Search

2013-10-01

This research studies the effectiveness of a dynamic message sign (DMS) using a driving : simulator. Over 100 subjects from different socio-economic and age groups were recruited to : drive the simulator under different traffic and driving conditions...

Can We Study Autonomous Driving Comfort in Moving-Base Driving Simulators? A Validation Study.

PubMed

Bellem, Hanna; Klüver, Malte; Schrauf, Michael; Schöner, Hans-Peter; Hecht, Heiko; Krems, Josef F

2017-05-01

To lay the basis of studying autonomous driving comfort using driving simulators, we assessed the behavioral validity of two moving-base simulator configurations by contrasting them with a test-track setting. With increasing level of automation, driving comfort becomes increasingly important. Simulators provide a safe environment to study perceived comfort in autonomous driving. To date, however, no studies were conducted in relation to comfort in autonomous driving to determine the extent to which results from simulator studies can be transferred to on-road driving conditions. Participants ( N = 72) experienced six differently parameterized lane-change and deceleration maneuvers and subsequently rated the comfort of each scenario. One group of participants experienced the maneuvers on a test-track setting, whereas two other groups experienced them in one of two moving-base simulator configurations. We could demonstrate relative and absolute validity for one of the two simulator configurations. Subsequent analyses revealed that the validity of the simulator highly depends on the parameterization of the motion system. Moving-base simulation can be a useful research tool to study driving comfort in autonomous vehicles. However, our results point at a preference for subunity scaling factors for both lateral and longitudinal motion cues, which might be explained by an underestimation of speed in virtual environments. In line with previous studies, we recommend lateral- and longitudinal-motion scaling factors of approximately 50% to 60% in order to obtain valid results for both active and passive driving tasks.

Awareness of driving disability in people with stroke tested in a simulator.

PubMed

Patomella, Ann-Helen; Kottorp, Anders; Tham, Kerstin

2008-09-01

The aim of this study was to explore and describe awareness of driving disability in people with driving difficulties after stroke. The study comprised a consecutive sample of 38 participants with stroke who showed difficulties in a technically advanced, interactive driving simulator. Driving ability in the simulator was measured using Performance Analysis of Driving Ability (P-Drive). Awareness of driving disability was measured using a modified version of Assessment of Awareness of Disability (AAD), measuring the discrepancy between observed driving actions and self-reported disability after a driving evaluation in a simulator. A majority of the participants (n = 36) demonstrated driving ability that was below the cut-off criterion for P-Drive. Furthermore, a majority of the items measuring awareness of driving disability were scored low, indicating that participants with stroke who did not pass a driving evaluation also had limited awareness of driving disability. A General Linear Model analysis indicated that awareness of driving disability and cognitive screening outcome explained 74% of the variance in driving ability. This study indicated that a majority of the people with stroke who fail a driving evaluation also have limited awareness of their disability, which indicates the need to address awareness in driving evaluations.

Training driving ability in a traumatic brain-injured individual using a driving simulator: a case report.

PubMed

Imhoff, Sarah; Lavallière, Martin; Germain-Robitaille, Mathieu; Teasdale, Normand; Fait, Philippe

2017-01-01

Traumatic brain injury (TBI) causes functional deficits that may significantly interfere with numerous activities of daily living such as driving. We report the case of a 20-year-old woman having lost her driver's license after sustaining a moderate TBI. We aimed to evaluate the effectiveness of an in-simulator training program with automated feedback on driving performance in a TBI individual. The participant underwent an initial and a final in-simulator driving assessment and 11 in-simulator training sessions with driving-specific automated feedbacks. Driving performance (simulation duration, speed regulation and lateral positioning) was measured in the driving simulator. Speeding duration decreased during training sessions from 1.50 ± 0.80 min (4.16 ± 2.22%) to 0.45 ± 0.15 min (0.44 ± 0.42%) but returned to initial duration after removal of feedbacks for the final assessment. Proper lateral positioning improved with training and was maintained at the final assessment. Time spent in an incorrect lateral position decreased from 18.85 min (53.61%) in the initial assessment to 1.51 min (4.64%) on the final assessment. Driving simulators represent an interesting therapeutic avenue. Considerable research efforts are needed to confirm the effectiveness of this method for driving rehabilitation of individuals who have sustained a TBI.

Driving with visual field loss : an exploratory simulation study

DOT National Transportation Integrated Search

2009-01-01

The goal of this study was to identify the influence of peripheral visual field loss (VFL) on driving performance in a motion-based driving simulator. Sixteen drivers (6 with VFL and 10 with normal visual fields) completed a 14 km simulated drive. Th...

Exploring travelers' behavior in response to dynamic message signs (DMS) using a driving simulator : final report.

DOT National Transportation Integrated Search

2013-10-01

This research studies the effectiveness of a dynamic message sign (DMS) using a driving : simulator. Over 100 subjects from different socio-economic and age groups were recruited to : drive the simulator under different traffic and driving conditions...

In Patients With Cirrhosis, Driving Simulator Performance Is Associated With Real-life Driving.

PubMed

Lauridsen, Mette M; Thacker, Leroy R; White, Melanie B; Unser, Ariel; Sterling, Richard K; Stravitz, Richard T; Matherly, Scott; Puri, Puneet; Sanyal, Arun J; Gavis, Edith A; Luketic, Velimir; Siddiqui, Muhammad S; Heuman, Douglas M; Fuchs, Michael; Bajaj, Jasmohan S

2016-05-01

Minimal hepatic encephalopathy (MHE) has been linked to higher real-life rates of automobile crashes and poor performance in driving simulation studies, but the link between driving simulator performance and real-life automobile crashes has not been clearly established. Furthermore, not all patients with MHE are unsafe drivers, but it is unclear how to distinguish them from unsafe drivers. We investigated the link between performance on driving simulators and real-life automobile accidents and traffic violations. We also aimed to identify features of unsafe drivers with cirrhosis and evaluated changes in simulated driving skills and MHE status after 1 year. We performed a study of outpatients with cirrhosis (n = 205; median 55 years old; median model for end-stage liver disease score, 9.5; none with overt hepatic encephalopathy or alcohol or illicit drug use within previous 6 months) seen at the Virginia Commonwealth University and McGuire Veterans Administration Medical Center, from November 2008 through April 2014. All participants were given paper-pencil tests to diagnose MHE (98 had MHE; 48%), and 163 patients completed a standardized driving simulation. Data were collected on traffic violations and automobile accidents from the Virginia Department of Motor Vehicles and from participants' self-assessments when they entered the study, and from 73 participants 1 year later. Participants also completed a questionnaire about alcohol use and cessation patterns. The driving simulator measured crashes, run-time, road center and edge excursions, and illegal turns during navigation; before and after each driving simulation session, patients were asked to rate their overall driving skills. Drivers were classified as safe or unsafe based on crashes and violations reported on official driving records; simulation results were compared with real-life driving records. Multivariable regression analyses of real-life crashes and violations was performed using data on demographics, cirrhosis details, MHE status, and alcohol cessation patterns, at baseline and at 1 year. Drivers categorized as unsafe had more crashes and made more illegal turns on the driving simulator than drivers categorized as safe; a higher proportion of subjects with MHE were categorized as unsafe drivers at baseline (16%) than subjects without MHE (7%; P = .02), and at 1-year follow-up (18% vs 0%; P = .02). Alcohol cessation within <1 year and illegal turns during simulator navigation tasks were associated with real-life automobile crashes and MHE in regression analysis; road edge excursions in the simulator were associated with real-life traffic violations. Personal assessment of driving skills improved after each simulation episode. In a study of 205 patients with cirrhosis, we associated results from driving simulation tests with real-life driving records and MHE. Traffic safety counseling should focus on patients with cirrhosis who recently quit consuming alcohol and perform poorly on driving simulation. Copyright © 2016 AGA Institute. Published by Elsevier Inc. All rights reserved.

Cognitive deficits are associated with poorer simulated driving in older adults with heart failure

PubMed Central

2013-01-01

Background Cognitive impairment is prevalent in older adults with heart failure (HF) and associated with reduced functional independence. HF patients appear at risk for reduced driving ability, as past work in other medical samples has shown cognitive dysfunction to be an important contributor to driving performance. The current study examined whether cognitive dysfunction was independently associated with reduced driving simulation performance in a sample of HF patients. Methods 18 persons with HF (67.72; SD = 8.56 year) completed echocardiogram and a brief neuropsychological test battery assessing global cognitive function, attention/executive function, memory and motor function. All participants then completed the Kent Multidimensional Assessment Driving Simulation (K-MADS), a driving simulator scenario with good psychometric properties. Results The sample exhibited an average Mini Mental State Examination (MMSE) score of 27.83 (SD = 2.09). Independent sample t-tests showed that HF patients performed worse than healthy adults on the driving simulation scenario. Finally, partial correlations showed worse attention/executive and motor function were independently associated with poorer driving simulation performance across several indices reflective of driving ability (i.e., centerline crossings, number of collisions, % of time over the speed limit, among others). Conclusion The current findings showed that reduced cognitive function was associated with poor simulated driving performance in older adults with HF. If replicated using behind-the-wheel testing, HF patients may be at elevated risk for unsafe driving and routine driving evaluations in this population may be warranted. PMID:24499466

Model Predictive Control Based Motion Drive Algorithm for a Driving Simulator

NASA Astrophysics Data System (ADS)

Rehmatullah, Faizan

In this research, we develop a model predictive control based motion drive algorithm for the driving simulator at Toronto Rehabilitation Institute. Motion drive algorithms exploit the limitations of the human vestibular system to formulate a perception of motion within the constrained workspace of a simulator. In the absence of visual cues, the human perception system is unable to distinguish between acceleration and the force of gravity. The motion drive algorithm determines control inputs to displace the simulator platform, and by using the resulting inertial forces and angular rates, creates the perception of motion. By using model predictive control, we can optimize the use of simulator workspace for every maneuver while simulating the vehicle perception. With the ability to handle nonlinear constraints, the model predictive control allows us to incorporate workspace limitations.

Expressing Anger Is More Dangerous than Feeling Angry when Driving

PubMed Central

Qu, Weina; Dai, Mengnuo; Zhao, Wenguo; Zhang, Kan

2016-01-01

Anger is an emotion that drivers often feel and express while driving, and it is believed by researchers to be an important cause of dangerous driving behavior. In this study, the relationships between driving trait anger, driving anger expression, and dangerous driving behaviors were analyzed. The Driving Anger Scale (DAS) was used to measure driving trait anger, whereas the Driving Anger Expression (DAX) Inventory was used to measure expressions of driving anger. A sample of 38 drivers completed the DAS, DAX, and a driving simulation session on a simulator where their driving behaviors were recorded. Correlation analysis showed that the higher scores on the DAS were associated with longer durations of speeding in the simulator. The more participants expressed their anger in verbal and physical ways, the more likely they were to crash the virtual vehicle during the simulation. Regression analyses illustrated the same pattern. The findings suggest that, although trait anger is related to speeding, the passive expression of anger is the real factor underling traffic accidents. This study extends findings about the predictive effects of self-report scales of driving behaviors to behaviors recorded on a simulator. Thus, if in traffic safety propaganda, guiding drivers to use positive ways to cope with driving anger is recommended by our findings. PMID:27258144

Expressing Anger Is More Dangerous than Feeling Angry when Driving.

PubMed

Qu, Weina; Dai, Mengnuo; Zhao, Wenguo; Zhang, Kan; Ge, Yan

2016-01-01

Anger is an emotion that drivers often feel and express while driving, and it is believed by researchers to be an important cause of dangerous driving behavior. In this study, the relationships between driving trait anger, driving anger expression, and dangerous driving behaviors were analyzed. The Driving Anger Scale (DAS) was used to measure driving trait anger, whereas the Driving Anger Expression (DAX) Inventory was used to measure expressions of driving anger. A sample of 38 drivers completed the DAS, DAX, and a driving simulation session on a simulator where their driving behaviors were recorded. Correlation analysis showed that the higher scores on the DAS were associated with longer durations of speeding in the simulator. The more participants expressed their anger in verbal and physical ways, the more likely they were to crash the virtual vehicle during the simulation. Regression analyses illustrated the same pattern. The findings suggest that, although trait anger is related to speeding, the passive expression of anger is the real factor underling traffic accidents. This study extends findings about the predictive effects of self-report scales of driving behaviors to behaviors recorded on a simulator. Thus, if in traffic safety propaganda, guiding drivers to use positive ways to cope with driving anger is recommended by our findings.

Simulation and Testing of a Linear Array of Modified Four-Square Feed Antennas for the Tianlai Cylindrical Radio Telescope

NASA Astrophysics Data System (ADS)

Cianciara, Aleksander J.; Anderson, Christopher J.; Chen, Xuelei; Chen, Zhiping; Geng, Jingchao; Li, Jixia; Liu, Chao; Liu, Tao; Lu, Wing; Peterson, Jeffrey B.; Shi, Huli; Steffel, Catherine N.; Stebbins, Albert; Stucky, Thomas; Sun, Shijie; Timbie, Peter T.; Wang, Yougang; Wu, Fengquan; Zhang, Juyong

A wide bandwidth, dual polarized, modified four-square antenna is presented as a feed antenna for radio astronomical measurements. A linear array of these antennas is used as a line-feed for cylindrical reflectors for Tianlai, a radio interferometer designed for 21cm intensity mapping. Simulations of the feed antenna beam patterns and scattering parameters are compared to experimental results at multiple frequencies across the 650-1420MHz range. Simulations of the beam patterns of the combined feed array/reflector are presented as well.

Novel AC Servo Rotating and Linear Composite Driving Device for Plastic Forming Equipment

NASA Astrophysics Data System (ADS)

Liang, Jin-Tao; Zhao, Sheng-Dun; Li, Yong-Yi; Zhu, Mu-Zhi

2017-07-01

The existing plastic forming equipment are mostly driven by traditional AC motors with long transmission chains, low efficiency, large size, low precision and poor dynamic response are the common disadvantages. In order to realize high performance forming processes, the driving device should be improved, especially for complicated processing motions. Based on electric servo direct drive technology, a novel AC servo rotating and linear composite driving device is proposed, which features implementing both spindle rotation and feed motion without transmission, so that compact structure and precise control can be achieved. Flux switching topology is employed in the rotating drive component for strong robustness, and fractional slot is employed in the linear direct drive component for large force capability. Then the mechanical structure for compositing rotation and linear motion is designed. A device prototype is manufactured, machining of each component and the whole assembly are presented respectively. Commercial servo amplifiers are utilized to construct the control system of the proposed device. To validate the effectiveness of the proposed composite driving device, experimental study on the dynamic test benches are conducted. The results indicate that the output torque can attain to 420 N·m and the dynamic tracking errors are less than about 0.3 rad in the rotating drive. the dynamic tracking errors are less than about 1.6 mm in the linear feed. The proposed research provides a method to construct high efficiency and accuracy direct driving device in plastic forming equipment.

Driving simulator sickness: Impact on driving performance, influence of blood alcohol concentration, and effect of repeated simulator exposures.

PubMed

Helland, Arne; Lydersen, Stian; Lervåg, Lone-Eirin; Jenssen, Gunnar D; Mørland, Jørg; Slørdal, Lars

2016-09-01

Simulator sickness is a major obstacle to the use of driving simulators for research, training and driver assessment purposes. The purpose of the present study was to investigate the possible influence of simulator sickness on driving performance measures such as standard deviation of lateral position (SDLP), and the effect of alcohol or repeated simulator exposure on the degree of simulator sickness. Twenty healthy male volunteers underwent three simulated driving trials of 1h's duration with a curvy rural road scenario, and rated their degree of simulator sickness after each trial. Subjects drove sober and with blood alcohol concentrations (BAC) of approx. 0.5g/L and 0.9g/L in a randomized order. Simulator sickness score (SSS) did not influence the primary outcome measure SDLP. Higher SSS significantly predicted lower average speed and frequency of steering wheel reversals. These effects seemed to be mitigated by alcohol. Higher BAC significantly predicted lower SSS, suggesting that alcohol inebriation alleviates simulator sickness. The negative relation between the number of previous exposures to the simulator and SSS was not statistically significant, but is consistent with habituation to the sickness-inducing effects, as shown in other studies. Overall, the results suggest no influence of simulator sickness on SDLP or several other driving performance measures. However, simulator sickness seems to cause test subjects to drive more carefully, with lower average speed and fewer steering wheel reversals, hampering the interpretation of these outcomes as measures of driving impairment and safety. BAC and repeated simulator exposures may act as confounding variables by influencing the degree of simulator sickness in experimental studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

HIERARCHIAL DESIGN AND EVALUATION OF PROCESSES TO GENERATE WASTE-RECYCLED FEEDS

EPA Science Inventory

Hierarchical Design and Evaluation of Processes to Generate
Waste-Recycled Feeds

Raymond L. Smith
U.S. Environmental Protection Agency
Office of Research and Development
National Risk Management Research Laboratory
26 W. Martin Luther King Drive
Cincinna...

[Relevance of a driving simulator in the assessment of handicapped individuals].

PubMed

Carroz, A; Comte, P-A; Nicolo, D; Dériaz, O; Vuadens, P

2008-06-01

To evaluate the value of our driving simulator in deciding whether or not to allow patients with physical and/or cognitive deficits to resuming driving and to analyze whether or not the medical expert's final decision is based more on the results of the driving simulator than those of the neuropsychological examination. One hundred and twenty-three patients were evaluated with the driving simulator. Thirty-five of those with cognitive deficits also underwent a neuropsychological examination prior to the medical expert's decision on driving aptitude. In cases of uncertainty or disagreement, a driving assessment in real conditions was performed by a driving instructor. In cases of physical handicap, the medical expert's decision concurred with that of the occupational therapist. For brain-injured patients, there was a significant correlation between the neuropsychologist's opinion and that of the occupational therapist (kappa=0.33; P=0.01). However, the sensibility and specificity were only 55 and 80%, respectively. The correlation between an occupational therapy decision based on the driving simulator and that of the medical expert was very significant (kappa=0.81; P<0.0001) and the sensibility and specificity were 84 and 100%, respectively. In contrast, these values were lower (63 and 71%, respectively) for the correlation between the neuropsychologist's opinion and that of the medical expert. Our driving simulator enables the danger-free evaluation of driving aptitude. The results mirror an in situ assessment and are more sensitive than neuropsychological examination. In fact, the neuropsychologist's opinion often is more negative or uncertain with respect to the patient's real driving aptitude. When taking a decision on a patient's driving aptitude, the medical expert is more inclined to trust the results of the driving simulator.

Application of the Environmental Sensation Learning Vehicle Simulation Platform in Virtual Reality

ERIC Educational Resources Information Center

Hsu, Kuei-Shu; Jiang, Jinn-Feng; Wei, Hung-Yuan; Lee, Tsung-Han

2016-01-01

The use of simulation technologies in learning has received considerable attention in recent years, but few studies to date have focused on vehicle driving simulation systems. In this study, a vehicle driving simulation system was developed to support novice drivers in practicing their skills. Specifically, the vehicle driving simulation system…

Transition to manual: Comparing simulator with on-road control transitions.

PubMed

Eriksson, A; Banks, V A; Stanton, N A

2017-05-01

Whilst previous research has explored how driver behaviour in simulators may transfer to the open road, there has been relatively little research showing the same transfer within the field of driving automation. As a consequence, most research into human-automation interaction has primarily been carried out in a research laboratory or on closed-circuit test tracks. The aim of this study was to assess whether research into non-critical control transactions in highly automated vehicles performed in driving simulators correlate with road driving conditions. Twenty six drivers drove a highway scenario using an automated driving mode in the simulator and twelve drivers drove on a public motorway in a Tesla Model S with the Autopilot activated. Drivers were asked to relinquish, or resume control from the automation when prompted by the vehicle interface in both the simulator and on road condition. Drivers were generally faster to resume control in the on-road driving condition. However, strong positive correlations were found between the simulator and on road driving conditions for drivers transferring control to and from automation. No significant differences were found with regard to workload, perceived usefulness and satisfaction between the simulator and on-road drives. The results indicate high levels of relative validity of driving simulators as a research tool for automated driving research. Copyright © 2017 Elsevier Ltd. All rights reserved.

Training driving ability in a traumatic brain-injured individual using a driving simulator: a case report

PubMed Central

Imhoff, Sarah; Lavallière, Martin; Germain-Robitaille, Mathieu; Teasdale, Normand; Fait, Philippe

2017-01-01

Background Traumatic brain injury (TBI) causes functional deficits that may significantly interfere with numerous activities of daily living such as driving. We report the case of a 20-year-old woman having lost her driver’s license after sustaining a moderate TBI. Objective We aimed to evaluate the effectiveness of an in-simulator training program with automated feedback on driving performance in a TBI individual. Methods The participant underwent an initial and a final in-simulator driving assessment and 11 in-simulator training sessions with driving-specific automated feedbacks. Driving performance (simulation duration, speed regulation and lateral positioning) was measured in the driving simulator. Results Speeding duration decreased during training sessions from 1.50 ± 0.80 min (4.16 ± 2.22%) to 0.45 ± 0.15 min (0.44 ± 0.42%) but returned to initial duration after removal of feedbacks for the final assessment. Proper lateral positioning improved with training and was maintained at the final assessment. Time spent in an incorrect lateral position decreased from 18.85 min (53.61%) in the initial assessment to 1.51 min (4.64%) on the final assessment. Conclusion Driving simulators represent an interesting therapeutic avenue. Considerable research efforts are needed to confirm the effectiveness of this method for driving rehabilitation of individuals who have sustained a TBI. PMID:28243152

Advanced simulation model for IPM motor drive with considering phase voltage and stator inductance

NASA Astrophysics Data System (ADS)

Lee, Dong-Myung; Park, Hyun-Jong; Lee, Ju

2016-10-01

This paper proposes an advanced simulation model of driving system for Interior Permanent Magnet (IPM) BrushLess Direct Current (BLDC) motors driven by 120-degree conduction method (two-phase conduction method, TPCM) that is widely used for sensorless control of BLDC motors. BLDC motors can be classified as SPM (Surface mounted Permanent Magnet) and IPM motors. Simulation model of driving system with SPM motors is simple due to the constant stator inductance regardless of the rotor position. Simulation models of SPM motor driving system have been proposed in many researches. On the other hand, simulation models for IPM driving system by graphic-based simulation tool such as Matlab/Simulink have not been proposed. Simulation study about driving system of IPMs with TPCM is complex because stator inductances of IPM vary with the rotor position, as permanent magnets are embedded in the rotor. To develop sensorless scheme or improve control performance, development of control algorithm through simulation study is essential, and the simulation model that accurately reflects the characteristic of IPM is required. Therefore, this paper presents the advanced simulation model of IPM driving system, which takes into account the unique characteristic of IPM due to the position-dependent inductances. The validity of the proposed simulation model is validated by comparison to experimental and simulation results using IPM with TPCM control scheme.

Chinese carless young drivers' self-reported driving behavior and simulated driving performance.

PubMed

Zhang, Qian; Jiang, Zuhua; Zheng, Dongpeng; Man, Dong; Xu, Xunnan

2013-01-01

Carless young drivers refers to those drivers aged between 18 and 25 years who have a driver's license but seldom have opportunities to practice their driving skills because they do not have their own cars. Due to China's lower private car ownership, many young drivers become carless young drivers after licensure, and the safety issue associated with them has raised great concern in China. This study aims to provide initial insight into the self-reported driving behaviors and simulated driving performance of Chinese carless young drivers. Thirty-three carless young drivers and 32 young drivers with their own cars (as a comparison group) participated in this study. A modified Driver Behavior Questionnaire (DBQ) with a 4-factor structure (errors, violations, attention lapses, and memory lapses) was used to study carless young drivers' self-reported driving behaviors. A simulated driving experiment using a low-cost, fixed-base driving simulator was conducted to measure their simulated driving performance (errors, violations, attention lapses, driving maintenance, reaction time, and accidents). Self-reported DBQ outcomes showed that carless young drivers reported similar errors, more attention lapses, fewer memory lapses, and significantly fewer violation behaviors relative to young drivers with their own cars, whereas simulated driving results revealed that they committed significantly more errors, attention lapses, and violation behaviors than the comparison group. Carless young drivers had a lower ability to maintain the stability of speed and lane position, drove more cautiously approaching and passing through red traffic lights, and committed more accidents during simulated driving. A tendency to speed was not found among carless young drivers; their average speed and speeding frequency were all much lower than that of the comparison group. Lifetime mileage was the only significant predictor of carless young drivers' self-reported violations, simulated violations, speed, and reaction time, whereas no significant predictor was found for young drivers with their own cars. Carless young drivers had poorer driving performance and were more overconfident of their self-reported driving skills compared to those young drivers with greater access to vehicles. Given that the lifetime mileage positively predicted the simulated violations measure of carless young drivers, immediate interventions are needed to help them increase driving exposure and gain driving experience gradually before moving to more challenging on-road driving tasks. Supplemental materials are available for this article.

Driving Competence in Mild Dementia with Lewy Bodies: In Search of Cognitive Predictors Using Driving Simulation

PubMed Central

Yamin, Stephanie; Stinchcombe, Arne; Gagnon, Sylvain

2015-01-01

Driving is a multifactorial behaviour drawing on multiple cognitive, sensory, and physical systems. Dementia is a progressive and degenerative neurological condition that impacts the cognitive processes necessary for safe driving. While a number of studies have examined driving among individuals with Alzheimer's disease, less is known about the impact of Dementia with Lewy Bodies (DLB) on driving safety. The present study compared simulated driving performance of 15 older drivers with mild DLB with that of 21 neurologically healthy control drivers. DLB drivers showed poorer performance on all indicators of simulated driving including an increased number of collisions in the simulator and poorer composite indicators of overall driving performance. A measure of global cognitive function (i.e., the Mini Mental State Exam) was found to be related to the overall driving performance. In addition, measures of attention (i.e., Useful Field of View, UFOV) and space processing (Visual Object and Space Perception, VOSP, Test) correlated significantly with a rater's assessment of driving performance. PMID:26713169

2011 Feds Feed Families

NASA Image and Video Library

2011-07-01

NASA employees Anita Douglas (l to r), Amy Grose, Aaron Brooks and Cabrina Bell sort through early contributions to the 2011 Feds Feed Families Food Drive at Stennis Space Center. Each summer for three years, federal agencies across the nation have worked together to collect nonperishable food for local food banks across the country.

Forward osmosis membrane modular configurations for osmotic dilution of seawater by forward osmosis and reverse osmosis hybrid system.

PubMed

Kim, Jung Eun; Phuntsho, Sherub; Ali, Syed Muztuza; Choi, Joon Young; Shon, Ho Kyong

2018-01-01

This study evaluates various options for full-scale modular configuration of forward osmosis (FO) process for osmotic dilution of seawater using wastewater for simultaneous desalination and water reuse through FO-reverse osmosis (RO) hybrid system. Empirical relationship obtained from one FO membrane element operation was used to simulate the operational performances of different FO module configurations. The main limiting criteria for module operation is to always maintain the feed pressure higher than the draw pressure throughout the housing module for safe operation without affecting membrane integrity. Experimental studies under the conditions tested in this study show that a single membrane housing cannot accommodate more than four elements as the draw pressure exceeds the feed pressure. This then indicates that a single stage housing with eight elements is not likely to be practical for safe FO operation. Hence, six different FO modular configurations were proposed and simulated. A two-stage FO configuration with multiple housings (in parallel) in the second stage using same or larger spacer thickness reduces draw pressure build-up as the draw flow rates are reduced to half in the second stage thereby allowing more than four elements in the second stage housing. The loss of feed pressure (pressure drop) and osmotic driving force in the second stage are compensated by operating under the pressure assisted osmosis (PAO) mode, which helps enhance permeate flux and maintains positive pressure differences between the feed and draw chamber. The PAO energy penalty is compensated by enhanced permeate throughput, reduced membrane area, and plant footprint. The contribution of FO/PAO to total energy consumption was not significant compared to post RO desalination (90%) indicating that the proposed two-stage FO modular configuration is one way of making the FO full-scale operation practical for FO-RO hybrid system. Copyright © 2017 Elsevier Ltd. All rights reserved.

Support for stroke patients in resumption of driving: patient survey and driving simulator trial

PubMed Central

Hitosugi, Masahito; Takehara, Itaru; Watanabe, Shu; Hayashi, Yasufumi; Tokudome, Shogo

2011-01-01

Background: Encouragement of stroke patients to resume driving is important to promote their reintegration into the community. Limited rehabilitation has been performed in this regard, owing to lack of specific knowledge on the part of medical staff. To establish an effective support program for stroke patients who wish to resume driving, we propose comprehensive training by medical staff using a driving simulator. Methods: A survey of stroke patients admitted to the Tokyo Metropolitan Rehabilitation Hospital was first performed. A questionnaire was sent to 525 patients. Of 218 responses, the answers of 118 patients who had been driving before their stroke were analyzed. More than 80% of stroke patients did not obtain enough information about resuming driving during their hospital stay, and 38.1% of patients would have liked to have had driving training with a simulator. From these results, we set out to determine the effect of driving training using a realistic and technically advanced driving simulator. Twenty-four stroke patients and 20 healthy controls were included in the study. Results: Repeat training with the simulator resulted in an increased ability to perform braking and an improvement in driving ability. The majority of stroke patients who had the mental and physical ability to drive a car were likely to be assessed as being able to resume driving as a result of the training program. Conclusion: This study indicates that comprehensive support by medical staff and provision of adequate information about resumption of driving and the opportunity for training on a driving simulator are likely to aid resumption of driving by stroke patients, thus enhancing their rehabilitation and social reintegration. PMID:21475633

Simulated Driving Assessment (SDA) for Teen Drivers: Results from a Validation Study

PubMed Central

McDonald, Catherine C.; Kandadai, Venk; Loeb, Helen; Seacrist, Thomas S.; Lee, Yi-Ching; Winston, Zachary; Winston, Flaura K.

2015-01-01

Background Driver error and inadequate skill are common critical reasons for novice teen driver crashes, yet few validated, standardized assessments of teen driving skills exist. The purpose of this study was to evaluate the construct and criterion validity of a newly developed Simulated Driving Assessment (SDA) for novice teen drivers. Methods The SDA's 35-minute simulated drive incorporates 22 variations of the most common teen driver crash configurations. Driving performance was compared for 21 inexperienced teens (age 16–17 years, provisional license ≤90 days) and 17 experienced adults (age 25–50 years, license ≥5 years, drove ≥100 miles per week, no collisions or moving violations ≤3 years). SDA driving performance (Error Score) was based on driving safety measures derived from simulator and eye-tracking data. Negative driving outcomes included simulated collisions or run-off-the-road incidents. A professional driving evaluator/instructor reviewed videos of SDA performance (DEI Score). Results The SDA demonstrated construct validity: 1.) Teens had a higher Error Score than adults (30 vs. 13, p=0.02); 2.) For each additional error committed, the relative risk of a participant's propensity for a simulated negative driving outcome increased by 8% (95% CI: 1.05–1.10, p<0.01). The SDA demonstrated criterion validity: Error Score was correlated with DEI Score (r=−0.66, p<0.001). Conclusions This study supports the concept of validated simulated driving tests like the SDA to assess novice driver skill in complex and hazardous driving scenarios. The SDA, as a standard protocol to evaluate teen driver performance, has the potential to facilitate screening and assessment of teen driving readiness and could be used to guide targeted skill training. PMID:25740939

i3Drive, a 3D interactive driving simulator.

PubMed

Ambroz, Miha; Prebil, Ivan

2010-01-01

i3Drive, a wheeled-vehicle simulator, can accurately simulate vehicles of various configurations with up to eight wheels in real time on a desktop PC. It presents the vehicle dynamics as an interactive animation in a virtual 3D environment. The application is fully GUI-controlled, giving users an easy overview of the simulation parameters and letting them adjust those parameters interactively. It models all relevant vehicle systems, including the mechanical models of the suspension, power train, and braking and steering systems. The simulation results generally correspond well with actual measurements, making the system useful for studying vehicle performance in various driving scenarios. i3Drive is thus a worthy complement to other, more complex tools for vehicle-dynamics simulation and analysis.

Driving performance in a power wheelchair simulator.

PubMed

Archambault, Philippe S; Tremblay, Stéphanie; Cachecho, Sarah; Routhier, François; Boissy, Patrick

2012-05-01

A power wheelchair simulator can allow users to safely experience various driving tasks. For such training to be efficient, it is important that driving performance be equivalent to that in a real wheelchair. This study aimed at comparing driving performance in a real and in a simulated environment. Two groups of healthy young adults performed different driving tasks, either in a real power wheelchair or in a simulator. Smoothness of joystick control as well as the time necessary to complete each task were recorded and compared between the two groups. Driving strategies were analysed from video recordings. The sense of presence, of really being in the virtual environment, was assessed through a questionnaire. Smoothness of joystick control was the same in the real and virtual groups. Task completion time was higher in the simulator for the more difficult tasks. Both groups showed similar strategies and difficulties. The simulator generated a good sense of presence, which is important for motivation. Performance was very similar for power wheelchair driving in the simulator or in real life. Thus, the simulator could potentially be used to complement training of individuals who require a power wheelchair and use a regular joystick. [Box: see text].

Daytime Sleepiness and Driving Performance in Patients with Obstructive Sleep Apnea: Comparison of the MSLT, the MWT, and a Simulated Driving Task

PubMed Central

Pizza, Fabio; Contardi, Sara; Mondini, Susanna; Trentin, Lino; Cirignotta, Fabio

2009-01-01

Study Objectives: To test the reliability of a driving-simulation test for the objective measurement of daytime alertness compared with the Multiple Sleep Latency Test (MSLT) and with the Maintenance of Wakefulness Test (MWT), and to test the ability to drive safely, in comparison with on-road history, in the clinical setting of untreated severe obstructive sleep apnea. Design: N/A. Setting: Sleep laboratory. Patients or Participants: Twenty-four patients with severe obstructive sleep apnea and reported daytime sleepiness varying in severity (as measured by the Epworth Sleepiness Scale). Interventions: N/A. Measurements and Results: Patients underwent MSLT and MWT coupled with 4 sessions of driving-simulation test on 2 different days randomly distributed 1 week apart. Simulated-driving performance (in terms of lane-position variability and crash occurrence) was correlated with sleep latency on the MSLT and more significantly on the MWT, showing a predictive validity toward the detection of sleepy versus alert patients with obstructive sleep apnea. In addition, patients reporting excessive daytime sleepiness or a history of car crashes showed poorer performances on the driving simulator. Conclusions: A simulated driving test is a suitable tool for objective measurement of daytime alertness in patients with obstructive sleep apnea. Further studies are needed to clarify the association between simulated-driving performance and on-road crash risk of patients with sleep disordered breathing. Citation: Pizza F; Contardi S; Mondini S; Trentin L; Cirignotta F. Daytime sleepiness and driving performance in patients with obstructive sleep apnea: comparison of the MSLT, the MWT, and a simulated driving task. SLEEP 2009;32(3):382-391. PMID:19294958

Improving Drive Files for Vehicle Road Simulations

NASA Astrophysics Data System (ADS)

Cherng, John G.; Goktan, Ali; French, Mark; Gu, Yi; Jacob, Anil

2001-09-01

Shaker tables are commonly used in laboratories for automotive vehicle component testing to study durability and acoustics performance. An example is development testing of car seats. However, it is difficult to repeat the measured road data perfectly with the response of a shaker table as there are basic differences in dynamic characteristics between a flexible vehicle and substantially rigid shaker table. In addition, there are performance limits in the shaker table drive systems that can limit correlation. In practice, an optimal drive signal for the actuators is created iteratively. During each iteration, the error between the road data and the response data is minimised by an optimising algorithm which is generally a part of the feed back loop of the shake table controller. This study presents a systematic investigation to the errors in time and frequency domains as well as joint time-frequency domain and an evaluation of different digital signal processing techniques that have been used in previous work. In addition, we present an innovative approach that integrates the dynamic characteristics of car seats and the human body into the error-minimising iteration process. We found that the iteration process can be shortened and the error reduced by using a weighting function created by normalising the frequency response function of the car seat. Two road data test sets were used in the study.

FINAL REPORT INTEGRATED DM1200 MELTER TESTING USING AZ 102 AND C 106/AY-102 HLW SIMULANTS: HLW SIMULANT VERIFICATION VSL-05R5800-1 REV 0 6/27/05

DOE Office of Scientific and Technical Information (OSTI.GOV)

KRUGER AA; MATLACK KS; GONG W

2011-12-29

The principal objectives of the DM1200 melter tests were to determine the effects of feed rheology, feed solid content, and bubbler configuration on glass production rate and off-gas system performance while processing the HLW AZ-101 and C-106/AY-102 feed compositions; characterize melter off-gas emissions; characterize the performance of the prototypical off-gas system components, as well as their integrated performance; characterize the feed, glass product, and off-gas effluents; and perform pre- and post test inspections of system components. The specific objectives (including test success criteria) of this testing, along with how each objective was met, are outlined in a table. The datamore » provided in this Final Report address the impacts of HLW melter feed rheology on melter throughput and validation of the simulated HLW melter feeds. The primary purpose of this testing is to further validate/verify the HLW melter simulants that have been used for previous melter testing and to support their continued use in developing melter and off-gas related processing information for the Project. The primary simulant property in question is rheology. Simulants and melter feeds used in all previous melter tests were produced by direct addition of chemicals; these feed tend to be less viscous than rheological the upper-bound feeds made from actual wastes. Data provided here compare melter processing for the melter feed used in all previous DM100 and DM1200 tests (nominal melter feed) with feed adjusted by the feed vendor (NOAH Technologies) to be more viscous, thereby simulating more closely the upperbounding feed produced from actual waste. This report provides results of tests that are described in the Test Plan for this work. The Test Plan is responsive to one of several test objectives covered in the WTP Test Specification for this work; consequently, only part of the scope described in the Test Specification was addressed in this particular Test Plan. For the purpose of comparison, the tests reported here were performed with AZ-102 and C-106/AY-102 HLW simulants and glass compositions that are essentially the same as those used for recent DM1200 tests. One exception was the use of an alternate, higher-waste-loading C-106/AY-102 glass composition that was used in previous DM100 tests to further evaluate the performance of the optimized bubbler configuration.« less

Evaluation of driver behavior to hydroplaning in the state of Florida using driving simulation.

DOT National Transportation Integrated Search

2012-08-01

This project used a driving simulator to investigate patterns of drivers' behavior during various rainfall events using different roadway geometries. The authors conducted a literature review of previous transportation studies using driving simulator...

Dropout during a driving simulator study: A survival analysis.

PubMed

Matas, Nicole A; Nettelbeck, Ted; Burns, Nicholas R

2015-12-01

Simulator sickness is the occurrence of motion-sickness like symptoms that can occur during use of simulators and virtual reality technologies. This study investigated individual factors that contributed to simulator sickness and dropout while using a desktop driving simulator. Eighty-eight older adult drivers (mean age 72.82±5.42years) attempted a practice drive and two test drives. Participants also completed a battery of cognitive and visual assessments, provided information on their health and driving habits, and reported their experience of simulator sickness symptoms throughout the study. Fifty-two participants dropped out before completing the driving tasks. A time-dependent Cox Proportional Hazards model showed that female gender (HR=2.02), prior motion sickness history (HR=2.22), and Mini-SSQ score (HR=1.55) were associated with dropout. There were no differences between dropouts and completers on any of the cognitive abilities tests. Older adults are a high-risk group for simulator sickness. Within this group, female gender and prior motion sickness history are related to simulator dropout. Higher reported experience of symptoms of simulator sickness increased rates of dropout. The results highlight the importance of screening and monitoring of participants in driving simulation studies. Older adults, females, and those with a prior history of motion sickness may be especially at risk. Copyright © 2015 Elsevier Ltd and National Safety Council. All rights reserved.

Research and development of a control system for multi axis cooperative motion based on PMAC

NASA Astrophysics Data System (ADS)

Guo, Xiao-xiao; Dong, Deng-feng; Zhou, Wei-hu

2017-10-01

Based on Programmable Multi-axes Controller (PMAC), a design of a multi axis motion control system for the simulator of spatial targets' dynamic optical properties is proposed. According to analysis the properties of spatial targets' simulator motion control system, using IPC as the main control layer, TurboPMAC2 as the control layer to meet coordinated motion control, data acquisition and analog output. A simulator using 5 servomotors which is connected with speed reducers to drive the output axis was implemented to simulate the motion of both the sun and the space target. Based on PMAC using PID and a notch filter algorithm, negative feedback, the speed and acceleration feed forward algorithm to satisfy the axis' requirements of the good stability and high precision at low speeds. In the actual system, it shows that the velocity precision is higher than 0.04 s ° and the precision of repetitive positioning is better than 0.006° when each axis is at a low-speed. Besides, the system achieves the control function of multi axis coordinated motion. The design provides an important technical support for detecting spatial targets, also promoting the theoretical research.

Psychological predictors of college students' cell phone use while driving.

PubMed

Schlehofer, Michèle M; Thompson, Suzanne C; Ting, Sarah; Ostermann, Sharon; Nierman, Angela; Skenderian, Jessica

2010-07-01

Despite the known risk, many people talk on a phone while driving. This study explored psychological predictors of cell phone use while driving. College students (final N=69) completed a survey and predicted their driving performance both with and without a simultaneous phone conversation. Their actual performance on a driving simulator was then assessed. Cell phone use reduced performance on the simulation task. Further, perceiving oneself as good at compensating for driving distractions, overestimating one's performance on the driving simulator, and high illusory control predicted more frequent cell phone use while driving in everyday life. Finally, those who talked more frequently on a phone while driving had poorer real-world driving records. These findings suggest illusory control and positive illusions partly explain driver's decisions of whether to use cell phones while driving. Copyright 2010 Elsevier Ltd. All rights reserved.

Assessing Cognitive Ability and Simulator-Based Driving Performance in Poststroke Adults

PubMed Central

Falkmer, Torbjörn; Willstrand, Tania Dukic

2017-01-01

Driving is an important activity of daily living, which is increasingly relied upon as the population ages. It has been well-established that cognitive processes decline following a stroke and these processes may influence driving performance. There is much debate on the use of off-road neurological assessments and driving simulators as tools to predict driving performance; however, the majority of research uses unlicensed poststroke drivers, making the comparability of poststroke adults to that of a control group difficult. It stands to reason that in order to determine whether simulators and cognitive assessments can accurately assess driving performance, the baseline should be set by licenced drivers. Therefore, the aim of this study was to assess differences in cognitive ability and driving simulator performance in licensed community-dwelling poststroke drivers and controls. Two groups of licensed drivers (37 poststroke and 43 controls) were assessed using several cognitive tasks and using a driving simulator. The poststroke adults exhibited poorer cognitive ability; however, there were no differences in simulator performance between groups except that the poststroke drivers demonstrated less variability in driver headway. The application of these results as a prescreening toolbox for poststroke drivers is discussed. PMID:28559646

Pharyngeal sense organs drive robust sugar consumption in Drosophila

PubMed Central

LeDue, Emily E; Chen, Yu-Chieh; Jung, Aera Y; Dahanukar, Anupama; Gordon, Michael D

2015-01-01

The fly pharyngeal sense organs lie at the transition between external and internal nutrient sensing mechanisms. Here, we investigate the function of pharyngeal sweet gustatory receptor neurons (GRNs), demonstrating that they express a subset of the nine previously identified sweet receptors and respond to stimulation with a panel of sweet compounds. We show that pox-neuro (poxn) mutants lacking taste function in the legs and labial palps have intact pharyngeal sweet taste, which is both necessary and sufficient to drive preferred consumption of sweet compounds by prolonging ingestion. Moreover, flies putatively lacking all sweet taste show little preference for nutritive or non-nutritive sugars in a short-term feeding assay. Together, our data demonstrate that pharyngeal sense organs play an important role in directing sustained consumption of sweet compounds, and suggest that post-ingestive sugar sensing does not effectively drive food choice in a simple short-term feeding paradigm. PMID:25807033

Effect of simulator training on fitness-to-drive after stroke: a 5-year follow-up of a randomized controlled trial.

PubMed

Devos, Hannes; Akinwuntan, Abiodun Emmanuel; Nieuwboer, Alice; Ringoot, Isabelle; Van Berghen, Karen; Tant, Mark; Kiekens, Carlotte; De Weerdt, Willy

2010-01-01

No long-term studies have been reported on the effect of training programs on driving after stroke. The authors' primary aim was to determine the effect of simulator versus cognitive rehabilitation therapy on fitness-to-drive at 5 years poststroke. A second aim was to investigate differences in clinical characteristics between stroke survivors who resumed and stopped driving. In a previously reported randomized controlled trial, 83 stroke survivors received 15 hours of simulator training (n = 42) or cognitive therapy (n = 41). In this 5-year follow-up study, 61 participants were reassessed. Fitness-to-drive decisions were obtained from medical, visual, neuropsychological, and on-road tests; 44 participants (simulator group, n = 21; cognitive group, n = 23) completed all assessments. The primary outcome measures were fitness-to-drive decision and current driving status. The authors found that 5 years after stroke, 18 of 30 participants (60%) in the simulator group were considered fit to drive, compared with 15 of 31 (48%) in the cognitive group (P = .36); 34 of 61 (56%) participants were driving. Current drivers were younger (P = .04), had higher Barthel scores (P = .008), had less comorbidity (P = .01), and were less severely depressed (P = .02) than those who gave up driving. The advantage of simulator-based driving training over cognitive rehabilitation therapy, evident at 6 months poststroke, had faded 5 years later. Poststroke drivers were younger and less severely affected and depressed than nondrivers.

Potential Role of Masting by Introduced Bamboos in Deer Mice (Peromyscus maniculatus) Population Irruptions Holds Public Health Consequences

PubMed Central

Smith, Melissa C.; Gomulkiewicz, Richard; Mack, Richard N.

2015-01-01

We hypothesized that the ongoing naturalization of frost/shade tolerant Asian bamboos in North America could cause environmental consequences involving introduced bamboos, native rodents and ultimately humans. More specifically, we asked whether the eventual masting by an abundant leptomorphic (“running”) bamboo within Pacific Northwest coniferous forests could produce a temporary surfeit of food capable of driving a population irruption of a common native seed predator, the deer mouse (Peromyscus maniculatus), a hantavirus carrier. Single-choice and cafeteria-style feeding trials were conducted for deer mice with seeds of two bamboo species (Bambusa distegia and Yushania brevipaniculata), wheat, Pinus ponderosa, and native mixed diets compared to rodent laboratory feed. Adult deer mice consumed bamboo seeds as readily as they consumed native seeds. In the cafeteria-style feeding trials, Y. brevipaniculata seeds were consumed at the same rate as native seeds but more frequently than wheat seeds or rodent laboratory feed. Females produced a median litter of 4 pups on a bamboo diet. Given the ability of deer mice to reproduce frequently whenever food is abundant, we employed our feeding trial results in a modified Rosenzweig-MacArthur consumer-resource model to project the population-level response of deer mice to a suddenly available/rapidly depleted supply of bamboo seeds. The simulations predict rodent population irruptions and declines similar to reported cycles involving Asian and South American rodents but unprecedented in deer mice. Following depletion of a mast seed supply, the incidence of Sin Nombre Virus (SNV) transmission to humans could subsequently rise with dispersal of the peridomestic deer mice into nearby human settlements seeking food. PMID:25898267

Methodology for functional MRI of simulated driving.

PubMed

Kan, Karen; Schweizer, Tom A; Tam, Fred; Graham, Simon J

2013-01-01

The developed world faces major socioeconomic and medical challenges associated with motor vehicle accidents caused by risky driving. Functional magnetic resonance imaging (fMRI) of individuals using virtual reality driving simulators may provide an important research tool to assess driving safety, based on brain activity and behavior. A fMRI-compatible driving simulator was developed and evaluated in the context of straight driving, turning, and stopping in 16 young healthy adults. Robust maps of brain activity were obtained, including activation of the primary motor cortex, cerebellum, visual cortex, and parietal lobe, with limited head motion (<1.5 mm deviation from mean head position in the superior∕inferior direction in all subjects) and only minor correlations between head motion, steering, or braking behavior. These results are consistent with previous literature and suggest that with care, fMRI of simulated driving is a feasible undertaking.

High precision NC lathe feeding system rigid-flexible coupling model reduction technology

NASA Astrophysics Data System (ADS)

Xuan, He; Hua, Qingsong; Cheng, Lianjun; Zhang, Hongxin; Zhao, Qinghai; Mao, Xinkai

2017-08-01

This paper proposes the use of dynamic substructure method of reduction of order to achieve effective reduction of feed system for high precision NC lathe feeding system rigid-flexible coupling model, namely the use of ADAMS to establish the rigid flexible coupling simulation model of high precision NC lathe, and then the vibration simulation of the period by using the FD 3D damper is very effective for feed system of bolt connection reduction of multi degree of freedom model. The vibration simulation calculation is more accurate, more quickly.

Integrated Eye Tracking and Neural Monitoring for Enhanced Assessment of Mild TBI

DTIC Science & Technology

2015-04-01

virtual reality driving simulator data acquisition. Data collection for the pilot study is nearly complete and data analyses are currently under way...Training for primary study procedures including neuropsychological testing, eye- tracking, virtual reality driving simulator, and EEG data acquisition is...the virtual reality driving simulator. Participants are instructed to drive along a coastal highway while performing the target detection task

Simulated Driving Assessment (SDA) for teen drivers: results from a validation study.

PubMed

McDonald, Catherine C; Kandadai, Venk; Loeb, Helen; Seacrist, Thomas S; Lee, Yi-Ching; Winston, Zachary; Winston, Flaura K

2015-06-01

Driver error and inadequate skill are common critical reasons for novice teen driver crashes, yet few validated, standardised assessments of teen driving skills exist. The purpose of this study is to evaluate the construct and criterion validity of a newly developed Simulated Driving Assessment (SDA) for novice teen drivers. The SDA's 35 min simulated drive incorporates 22 variations of the most common teen driver crash configurations. Driving performance was compared for 21 inexperienced teens (age 16-17 years, provisional license ≤90 days) and 17 experienced adults (age 25-50 years, license ≥5 years, drove ≥100 miles per week, no collisions or moving violations ≤3 years). SDA driving performance (Error Score) was based on driving safety measures derived from simulator and eye-tracking data. Negative driving outcomes included simulated collisions or run-off-the-road incidents. A professional driving evaluator/instructor (DEI Score) reviewed videos of SDA performance. The SDA demonstrated construct validity: (1) teens had a higher Error Score than adults (30 vs. 13, p=0.02); (2) For each additional error committed, the RR of a participant's propensity for a simulated negative driving outcome increased by 8% (95% CI 1.05 to 1.10, p<0.01). The SDA-demonstrated criterion validity: Error Score was correlated with DEI Score (r=-0.66, p<0.001). This study supports the concept of validated simulated driving tests like the SDA to assess novice driver skill in complex and hazardous driving scenarios. The SDA, as a standard protocol to evaluate teen driver performance, has the potential to facilitate screening and assessment of teen driving readiness and could be used to guide targeted skill training. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

The Neural Correlates of Driving Performance Identified Using Positron Emission Tomography

ERIC Educational Resources Information Center

Horikawa, E.; Okamura, N.; Tashiro, M.; Sakurada, Y.; Maruyama, M.; Arai, H.; Yamaguchi, K.; Sasaki, H.; Yanai, K.; Itoh, M.

2005-01-01

Driving is a complex behavior involving multiple cognitive domains. To identify neural correlates of driving performance, [^1^5O]H"2O positron emission tomography was performed using a simulated driving task. Compared with the resting condition, simulated driving increased regional cerebral blood flow (rCBF) in the cerebellum, occipital, and…

Simple gaze-contingent cues guide eye movements in a realistic driving simulator

NASA Astrophysics Data System (ADS)

Pomarjanschi, Laura; Dorr, Michael; Bex, Peter J.; Barth, Erhardt

2013-03-01

Looking at the right place at the right time is a critical component of driving skill. Therefore, gaze guidance has the potential to become a valuable driving assistance system. In previous work, we have already shown that complex gaze-contingent stimuli can guide attention and reduce the number of accidents in a simple driving simulator. We here set out to investigate whether cues that are simple enough to be implemented in a real car can also capture gaze during a more realistic driving task in a high-fidelity driving simulator. We used a state-of-the-art, wide-field-of-view driving simulator with an integrated eye tracker. Gaze-contingent warnings were implemented using two arrays of light-emitting diodes horizontally fitted below and above the simulated windshield. Thirteen volunteering subjects drove along predetermined routes in a simulated environment popu­ lated with autonomous traffic. Warnings were triggered during the approach to half of the intersections, cueing either towards the right or to the left. The remaining intersections were not cued, and served as controls. The analysis of the recorded gaze data revealed that the gaze-contingent cues did indeed have a gaze guiding effect, triggering a significant shift in gaze position towards the highlighted direction. This gaze shift was not accompanied by changes in driving behaviour, suggesting that the cues do not interfere with the driving task itself.

Precision wire feeder for small diameter wire

DOEpatents

Brandon, Eldon D.; Hooper, Frederick M.; Reichenbach, Marvin L.

1992-01-01

A device for feeding small diameter wire having a diameter less than 0.04 mm (16 mil) to a welding station includes a driving wheel for controllably applying a non-deforming driving force to the wire to move the free end of the wire towards the welding station; and a tension device such as a torque motor for constantly applying a reverse force to the wire in opposition to the driving force to keep the wire taut.

Precision wire feeder for small diameter wire

DOEpatents

Brandon, E.D.; Hooper, F.M.; Reichenbach, M.L.

1992-08-11

A device for feeding small diameter wire having a diameter less than 0.04 mm (16 mil) to a welding station includes a driving wheel for controllably applying a non-deforming driving force to the wire to move the free end of the wire towards the welding station; and a tension device such as a torque motor for constantly applying a reverse force to the wire in opposition to the driving force to keep the wire taut. 1 figure.

Feeding Management in Infants with Craniofacial Anomalies.

PubMed

Merrow, Jill M

2016-11-01

The instinctual drive to gain nourishment can become complicated by structural differences, physiologic instability and environmental influences. Infants with craniofacial anomalies may experience significant feeding and swallowing difficulties related to the type and severity of the anomalies present as well as social-emotional interactions with caregivers. Typical outcome measures and feeding goals are discussed. Details regarding clinical and instrumental evaluation, including fiberoptic endoscopic evaluation of swallowing and modified barium swallow study, as well as management techniques are reported. Copyright © 2016 Elsevier Inc. All rights reserved.

The Effects of Dextromethorphan on Driving Performance and the Standardized Field Sobriety Test.

PubMed

Perry, Paul J; Fredriksen, Kristian; Chew, Stephanie; Ip, Eric J; Lopes, Ingrid; Doroudgar, Shadi; Thomas, Kelan

2015-09-01

Dextromethorphan (DXM) is abused most commonly among adolescents as a recreational drug to generate a dissociative experience. The objective of the study was to assess driving with and without DXM ingestion. The effects of one-time maximum daily doses of DXM 120 mg versus a guaifenesin 400 mg dose were compared among 40 healthy subjects using a crossover design. Subjects' ability to drive was assessed by their performance in a driving simulator (STISIM® Drive driving simulator software) and by conducting a standardized field sobriety test (SFST) administered 1-h postdrug administration. The one-time dose of DXM 120 mg did not demonstrate driving impairment on the STISIM® Drive driving simulator or increase SFST failures compared to guaifenesin 400 mg. Doses greater than the currently recommended maximum daily dose of 120 mg are necessary to perturb driving behavior. © 2015 American Academy of Forensic Sciences.

Test drives in the Daimler-Benz driving simulator with drivers under diazepam

DOT National Transportation Integrated Search

1990-05-01

The research project investigated the influence of diazepam on the driving performance measured in the Daimler-Benz Driving Simulator. Test subjects were male students; 20 received a medium, and 20 received a high dosage of diazepam. A third group of...

Arcuate hypothalamic AgRP and putative POMC neurons show opposite changes in spiking across multiple timescales

PubMed Central

Mandelblat-Cerf, Yael; Ramesh, Rohan N; Burgess, Christian R; Patella, Paola; Yang, Zongfang; Lowell, Bradford B; Andermann, Mark L

2015-01-01

Agouti-related-peptide (AgRP) neurons—interoceptive neurons in the arcuate nucleus of the hypothalamus (ARC)—are both necessary and sufficient for driving feeding behavior. To better understand the functional roles of AgRP neurons, we performed optetrode electrophysiological recordings from AgRP neurons in awake, behaving AgRP-IRES-Cre mice. In free-feeding mice, we observed a fivefold increase in AgRP neuron firing with mounting caloric deficit in afternoon vs morning recordings. In food-restricted mice, as food became available, AgRP neuron firing dropped, yet remained elevated as compared to firing in sated mice. The rapid drop in spiking activity of AgRP neurons at meal onset may reflect a termination of the drive to find food, while residual, persistent spiking may reflect a sustained drive to consume food. Moreover, nearby neurons inhibited by AgRP neuron photostimulation, likely including satiety-promoting pro-opiomelanocortin (POMC) neurons, demonstrated opposite changes in spiking. Finally, firing of ARC neurons was also rapidly modulated within seconds of individual licks for liquid food. These findings suggest novel roles for antagonistic AgRP and POMC neurons in the regulation of feeding behaviors across multiple timescales. DOI: http://dx.doi.org/10.7554/eLife.07122.001 PMID:26159614

Feed Forward Programming of Car Drivers’ Eye Movement Behavior: A System Theoretical Approach. Volume 2

DTIC Science & Technology

1980-03-01

a driver and emphasizes the potential applied value of this theoretical approach in improving driving safety . From a pragmatic point of view, it is...distance, there is less spare time to react after an essential target has been recognized. Because driving safety is of crucial importance under all con

Simulated driving and brain imaging: combining behavior, brain activity, and virtual reality.

PubMed

Carvalho, Kara N; Pearlson, Godfrey D; Astur, Robert S; Calhoun, Vince D

2006-01-01

Virtual reality in the form of simulated driving is a useful tool for studying the brain. Various clinical questions can be addressed, including both the role of alcohol as a modulator of brain function and regional brain activation related to elements of driving. We reviewed a study of the neural correlates of alcohol intoxication through the use of a simulated-driving paradigm and wished to demonstrate the utility of recording continuous-driving behavior through a new study using a programmable driving simulator developed at our center. Functional magnetic resonance imaging data was collected from subjects while operating a driving simulator. Independent component analysis (ICA) was used to analyze the data. Specific brain regions modulated by alcohol, and relationships between behavior, brain function, and alcohol blood levels were examined with aggregate behavioral measures. Fifteen driving epochs taken from two subjects while also recording continuously recorded driving variables were analyzed with ICA. Preliminary findings reveal that four independent components correlate with various aspects of behavior. An increase in braking while driving was found to increase activation in motor areas, while cerebellar areas showed signal increases during steering maintenance, yet signal decreases during steering changes. Additional components and significant findings are further outlined. In summary, continuous behavioral variables conjoined with ICA may offer new insight into the neural correlates of complex human behavior.

Relationship Between Motor Vehicle Collisions and Results of Perimetry, Useful Field of View, and Driving Simulation in Drivers With Glaucoma.

PubMed

Tatham, Andrew J; Boer, Erwin R; Gracitelli, Carolina P B; Rosen, Peter N; Medeiros, Felipe A

2015-05-01

To examine the relationship between Motor Vehicle Collisions (MVCs) in drivers with glaucoma and standard automated perimetry (SAP), Useful Field of View (UFOV), and driving simulator assessment of divided attention. A cross-sectional study of 153 drivers from the Diagnostic Innovations in Glaucoma Study. All subjects had SAP and divided attention was assessed using UFOV and driving simulation using low-, medium-, and high-contrast peripheral stimuli presented during curve negotiation and car following tasks. Self-reported history of MVCs and average mileage driven were recorded. Eighteen of 153 subjects (11.8%) reported a MVC. There was no difference in visual acuity but the MVC group was older, drove fewer miles, and had worse binocular SAP sensitivity, contrast sensitivity, and ability to divide attention (UFOV and driving simulation). Low contrast driving simulator tasks were the best discriminators of MVC (AUC 0.80 for curve negotiation versus 0.69 for binocular SAP and 0.59 for UFOV). Adjusting for confounding factors, longer reaction times to driving simulator divided attention tasks provided additional value compared with SAP and UFOV, with a 1 standard deviation (SD) increase in reaction time (approximately 0.75 s) associated with almost two-fold increased odds of MVC. Reaction times to low contrast divided attention tasks during driving simulation were significantly associated with history of MVC, performing better than conventional perimetric tests and UFOV. The association between conventional tests of visual function and MVCs in drivers with glaucoma is weak, however, tests of divided attention, particularly using driving simulation, may improve risk assessment.

Simulated Driving Changes in Young Adults with ADHD Receiving Mixed Amphetamine Salts Extended Release and Atomoxetine

ERIC Educational Resources Information Center

Kay, Gary G.; Michaels, M. Alex; Pakull, Barton

2009-01-01

Background: Psychostimulant treatment may improve simulated driving performance in young adults with attention-deficit/hyperactivity disorder (ADHD). Method: This was a randomized, double-blind, placebo-controlled, crossover study of simulated driving performance with mixed amphetamine salts--extended release (MAS XR) 50 mg/day (Cohort 1) and…

The Maintenance of Wakefulness Test and driving simulator performance.

PubMed

Banks, Siobhan; Catcheside, Peter; Lack, Leon C; Grunstein, Ron R; McEvoy, R Doug

2005-11-01

It has been suggested that the Maintenance of Wakefulness Test (MWT) may be clinically useful to assess fitness to drive, yet little is known about the actual relationship between sleep latency and driving performance. This study examined the ability of 2 MWT trials to predict driving-simulator performance in healthy individuals. Experimental. NA. Twenty healthy volunteers (mean age 22.8 years; 9 men). NA. The MWT and driving-simulator performance were examined under 2 conditions-partial sleep deprivation and a combination of partial sleep deprivation and alcohol consumption. Each subject was studied a week apart, with the order randomly assigned. Subjects completed a nighttime 70-minute AusEd driving simulation task and two 40-minute MWT trials, 1 before (MWT1) and 1 after (MWT2) the driving task. In the sleep-deprived condition, the MWT1 sleep latency was inversely correlated with braking reaction time. During the partial sleep deprivation and alcohol condition, the number of microsleeps during the driving task, steering deviation, braking reaction time, and crashes all negatively correlated with the MWT1 sleep latency. Additionally, construction of a receiver-operator characteristic curve revealed that MWT1 sleep latency in the partial sleep deprivation plus alcohol condition significantly discriminated subjects who had a crash from those who did not. These results indicate that sleep latency on the MWT is a reasonable predictor of driving simulator performance in sleepy, alcohol-impaired, normal subjects. Further research is needed to examine the relationship between daytime MWT results and driving simulator performance in sleepy patients (eg, those with obstructive sleep apnea) and in experimentally sleep-deprived normal subjects.

Structural equation model analysis for the evaluation of overall driving performance: A driving simulator study focusing on driver distraction.

PubMed

Papantoniou, Panagiotis

2018-04-03

The present research relies on 2 main objectives. The first is to investigate whether latent model analysis through a structural equation model can be implemented on driving simulator data in order to define an unobserved driving performance variable. Subsequently, the second objective is to investigate and quantify the effect of several risk factors including distraction sources, driver characteristics, and road and traffic environment on the overall driving performance and not in independent driving performance measures. For the scope of the present research, 95 participants from all age groups were asked to drive under different types of distraction (conversation with passenger, cell phone use) in urban and rural road environments with low and high traffic volume in a driving simulator experiment. Then, in the framework of the statistical analysis, a correlation table is presented investigating any of a broad class of statistical relationships between driving simulator measures and a structural equation model is developed in which overall driving performance is estimated as a latent variable based on several individual driving simulator measures. Results confirm the suitability of the structural equation model and indicate that the selection of the specific performance measures that define overall performance should be guided by a rule of representativeness between the selected variables. Moreover, results indicate that conversation with the passenger was not found to have a statistically significant effect, indicating that drivers do not change their performance while conversing with a passenger compared to undistracted driving. On the other hand, results support the hypothesis that cell phone use has a negative effect on driving performance. Furthermore, regarding driver characteristics, age, gender, and experience all have a significant effect on driving performance, indicating that driver-related characteristics play the most crucial role in overall driving performance. The findings of this study allow a new approach to the investigation of driving behavior in driving simulator experiments and in general. By the successful implementation of the structural equation model, driving behavior can be assessed in terms of overall performance and not through individual performance measures, which allows an important scientific step forward from piecemeal analyses to a sound combined analysis of the interrelationship between several risk factors and overall driving performance.

Manual transmission enhances attention and driving performance of ADHD adolescent males: pilot study.

PubMed

Cox, Daniel J; Punja, Mohan; Powers, Katie; Merkel, R Lawrence; Burket, Roger; Moore, Melissa; Thorndike, Frances; Kovatchev, Boris

2006-11-01

Inattention is a major contributor to driving mishaps and is especially problematic among adolescent drivers with ADHD, possibly contributing to their 2 to 4 times higher incidence of collisions. Manual transmission has been demonstrated to be associated with greater arousal. This study tests the hypotheses that manual transmission, compared to automatic transmission, would be associated with better attention and performance on a driving simulator. Ten adolescent drivers with ADHD practice driving on the simulator in the manual and automatic mode. Employing a single-blind, cross-over design, participants drive the simulator at 19:30 and 22:30 hr for 30 min in both transmissions and rate their attention to driving. Subjectively, participants report being more attentive while driving in manual transmission mode. Objectively, participants drive safer in the manual transmission mode. Although in need of replication, this pilot study suggests a behavioral intervention to improve driving performance among ADHD adolescents.

Alcohol Effects on Simulated Driving in Frequent and Infrequent Binge Drinkers

PubMed Central

Bernosky-Smith, Kimberly A.; Shannon, Erin E.; Roth, Alicia J.; Liguori, Anthony

2011-01-01

Objective Compared to non-bingers, binge drinkers are more likely to drive while intoxicated. The extent to which binge frequency impacts confidence in driving and subsequent driving impairment is unknown. This study compared the effects of an experimenter-delivered alcohol binge on subjective impairment and simulated driving ability in female High and Low Frequency bingers. Methods Female drinkers were assigned to High Frequency (n=30) or Low Frequency (n=30) binge groups based on their Alcohol Use Questionnaire responses. At 30-minute intervals within a two-hour period, participants received either a placebo drink (n=15 per group) or a 0.2 g/kg dose of alcohol (n=15 per group; cumulative dose 0.8 g/kg). Self-reported impairment, driving confidence, and simulated driving were then measured. Results Self-reported confidence in driving was significantly lower after alcohol than after placebo in Low Frequency but not High Frequency bingers. Self-reported impairment and collisions during simulated driving were significantly greater after alcohol than after placebo in both Low Frequency and High Frequency bingers. Conclusions The impairing effects of a single alcohol binge on driving ability in females are not influenced by binge frequency. However, high binge frequency may be associated with a less cautious approach to post-binge driving. PMID:21542027

Suitability of Synthetic Driving Profiles from Traffic Micro-Simulation for Real-World Energy Analysis: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hou, Yunfei; Wood, Eric; Burton, Evan

A shift towards increased levels of driving automation is generally expected to result in improved safety and traffic congestion outcomes. However, little empirical data exists to estimate the impact that automated driving could have on energy consumption and greenhouse gas emissions. In the absence of empirical data on differences between drive cycles from present day vehicles (primarily operated by humans) and future vehicles (partially or fully operated by computers) one approach is to model both situations over identical traffic conditions. Such an exercise requires traffic micro-simulation to not only accurately model vehicle operation under high levels of automation, but alsomore » (and potentially more challenging) vehicle operation under present day human drivers. This work seeks to quantify the ability of a commercial traffic micro-simulation program to accurately model real-world drive cycles in vehicles operated primarily by humans in terms of driving speed, acceleration, and simulated fuel economy. Synthetic profiles from models of freeway and arterial facilities near Atlanta, Georgia, are compared to empirical data collected from real-world drivers on the same facilities. Empirical and synthetic drive cycles are then simulated in a powertrain efficiency model to enable comparison on the basis of fuel economy. Synthetic profiles from traffic micro-simulation were found to exhibit low levels of transient behavior relative to the empirical data. Even with these differences, the synthetic and empirical data in this study agree well in terms of driving speed and simulated fuel economy. The differences in transient behavior between simulated and empirical data suggest that larger stochastic contributions in traffic micro-simulation (relative to those present in the traffic micro-simulation tool used in this study) are required to fully capture the arbitrary elements of human driving. Interestingly, the lack of stochastic contributions from models of human drivers in this study did not result in a significant discrepancy between fuel economy simulations based on synthetic and empirical data; a finding with implications on the potential energy efficiency gains of automated vehicle technology.« less

Driving simulator and neuropsychological [corrected] testing in OSAS before and under CPAP therapy.

PubMed

Orth, M; Duchna, H-W; Leidag, M; Widdig, W; Rasche, K; Bauer, T T; Walther, J W; de Zeeuw, J; Malin, J-P; Schultze-Werninghaus, G; Kotterba, S

2005-11-01

Patients with obstructive sleep apnoea syndrome (OSAS) have an increased car accident rate. Investigations on accident frequency are based on case history, insurance reports and driving simulator studies. The present study combines neuropsychological testing of different attention aspects engaged in driving a car and driving simulation to evaluate a suitable instrument for assessing therapeutic effects of continuous positive airway pressure (CPAP). Driving simulator investigation and neuropsychological testing of alertness, vigilance and divided attention were performed in 31 patients with polysomnographically confirmed OSAS (apnoea-hypopnoea index 24.8+/-21.5.h(-1)) before, and 2 and 42 days after initiation of CPAP. Divided attention and alertness improved significantly during CPAP, whereas vigilance remained unchanged. However, accident frequency (OSAS before therapy: 2.7+/-2.0; 2 days after CPAP: 1.5+/-1.4; 42 days after CPAP: 0.9+/-1.3) and frequency of concentration faults (OSAS before therapy: 12.4+/-5.1; 2 days after CPAP: 6.5+/-3.9; 42 days after CPAP: 4.9+/-3.3) decreased in the simulated driving situation after 2 and 42 days of therapy. There was no relation between accident frequency, concentration faults and daytime sleepiness, as measured by the Epworth Sleepiness Scale, and polysomnographic or neuropsychological findings, respectively. In conclusion, the present results suggest that driving simulation is a possible benchmark parameter of driving performance in obstructive sleep apnoea syndrome patients.

NCI at Frederick Contributes to Feds Feed Families | Poster

Cancer.gov

Once again, NCI at Frederick participated in the annual Feds Feed Families event, which challenges federal workers to help knock out hunger with a food drive. This year, NIH collected 26,315 pounds of non-perishable goods, beating its goal of collecting 20,000 pounds. This includes over four tons of food that was collected at satellite locations, including NCI at Frederick.

Marine debris ingestion by coastal dolphins: what drives differences between sympatric species?

PubMed

Di Beneditto, Ana Paula Madeira; Ramos, Renata Maria Arruda

2014-06-15

This study compared marine debris ingestion of the coastal dolphins Pontoporia blainvillei and Sotalia guianensis in a sympatric area in Atlantic Ocean. Among the 89 stomach contents samples of P. blainvillei, 14 (15.7%) contained marine debris. For S. guianensis, 77 stomach contents samples were analyzed and only one of which (1.30%) contained marine debris. The debris recovered was plastic material: nylon yarns and flexible plastics. Differences in feeding habits between the coastal dolphins were found to drive their differences regarding marine debris ingestion. The feeding activity of P. blainvillei is mainly near the sea bottom, which increases its chances of ingesting debris deposited on the seabed. In contrast, S. guianensis has a near-surface feeding habit. In the study area, the seabed is the main zone of accumulation of debris, and species with some degree of association with the sea bottom may be local bioindicators of marine debris pollution. Copyright © 2014 Elsevier Ltd. All rights reserved.

The impact of daily multiphase feeding on animal performance, body composition, nitrogen and phosphorus excretions, and feed costs in growing-finishing pigs.

PubMed

Pomar, C; Pomar, J; Dubeau, F; Joannopoulos, E; Dussault, J-P

2014-05-01

The effect of feeding pigs in a three-phase feeding (3PF) system or a daily-phase feeding (DPF) system on growth performance, body composition, and N and P excretions was studied on 8 pens of 10 pigs each. Feeds for the 3PF and DPF treatments were obtained by mixing two feeds, one with a high nutrient concentration and the other with a low nutrient concentration. The DPF pigs tended (P=0.08) to consume more feed (+3.7%) than the 3PF pigs, but only during the first feeding phase. The DPF pigs consumed 7.3% less protein (P<0.01) but a similar amount of total P. For the whole growing period, the DPF pigs tended (P=0.08) to gain more weight (+2.4%) than the 3PF pigs, mainly because of faster growth (P=0.02) during the first feeding period. At the end of the experiment, total body protein mass was similar in the two treatment groups, but the DPF pigs had 8% more body lipids (P=0.04) than the 3PF pigs. Daily multiphase feeding reduced N excretion by 12% (P<0.01) but did not significantly reduce P excretion. In addition, feed costs, nutrient intake and nutrient excretion under the two feeding strategies were simulated and compared after different approaches were used to formulate complete feeds for each phase of the 3PF system, as well as the two feeds used in the DPF program. Simulated feed intake and growth was similar to those observed in the animal experiment. In comparison with the simulated 3PF system, the feed cost for the DPF pigs was reduced by 1.0%, the simulated N and P intakes were reduced by 7.3% and 4.4%, respectively, and the expected N and P excretions were reduced by 12.6% and 6.6%, respectively. The concomitant adjustment of the dietary concentration of nutrients to match the evaluated requirements of pig populations can be an efficient approach to significantly reduce feeding costs and N and P excretions in pig production systems.

Bipedal vs. unipedal: a comparison between one-foot and two-foot driving in a driving simulator.

PubMed

Wang, Dong-Yuan Debbie; Richard, F Dan; Cino, Cullen R; Blount, Trevin; Schmuller, Joseph

2017-04-01

Is it better to drive with one foot or with two feet? Although two-foot driving has fostered interminable debate in the media, no scientific and systematic research has assessed this issue and federal and local state governments have provided no answers. The current study compared traditional unipedal (one-foot driving, using the right foot to control the accelerator and the brake pedal) with bipedal (two-foot driving, using the right foot to control the accelerator and the left foot to control the brake pedal) responses to a visual stimulus in a driving simulator study. Each of 30 undergraduate participants drove in a simulated driving scenario. They responded to a STOP sign displayed on the centre of the screen by bringing their vehicle to a complete stop. Brake RT was shorter under the bipedal condition, while throttle RT showed advantage under the unipedal condition. Stopping time and distance showed a bipedal advantage, however. We discuss further limitations of the current study and implications in a driving task. Before drawing any conclusions from the simulator study, further on-road driving tests are necessary to confirm these obtained bipedal advantages. Practitioner Summary: Traditional unipedal (using the right foot to control the accelerator and the brake pedal) with bipedal (using the right foot to control the accelerator and the left foot to control the brake pedal) responses to a visual stimulus in a driving simulator were compared. Our results showed a bipedal advantage. Promotion: Although two-foot driving has fostered interminable debate in the media, no scientific and systematic research has assessed this issue and federal and local state governments have provided no answers. Traditional (one-foot driving, using the right foot to control the accelerator and the brake pedal) with bipedal (using the right foot to control the accelerator and the left foot to control the brake pedal) responses to a visual stimulus in a simulated driving study were compared. Throttle reaction time was faster in the unipedal condition whereas brake reaction time, stopping time and stopping distance showed a bipedal advantage. We discuss further theoretical issues and implications in a driving task.

Modelling and Simulation of Single-Phase Series Active Compensator for Power Quality Improvement

NASA Astrophysics Data System (ADS)

Verma, Arun Kumar; Mathuria, Kirti; Singh, Bhim; Bhuvaneshwari, G.

2017-10-01

A single-phase active series compensator is proposed in this work to reduce harmonic currents at the ac mains and to regulate the dc link voltage of a diode bridge rectifier (DBR) that acts as the front end converter for a voltage source inverter feeding an ac motor. This ac motor drive is used in any of the domestic, commercial or industrial appliances. Under fluctuating ac mains voltages, the dc link voltage of the DBR depicts wide variations and hence the ac motor is used at reduced rating as compared to its name-plate rating. The active series compensator proposed here provides dual functions of improving the power quality at the ac mains and regulating the dc link voltage thus averting the need for derating of the ac motor.

The importance of hormonal circadian rhythms in daily feeding patterns: An illustration with simulated pigs.

PubMed

Boumans, Iris J M M; de Boer, Imke J M; Hofstede, Gert Jan; la Fleur, Susanne E; Bokkers, Eddie A M

2017-07-01

The interaction between hormonal circadian rhythms and feeding behaviour is not well understood. This study aimed to deepen our understanding of mechanisms underlying circadian feeding behaviour in animals, using pigs, Sus scrofa, as a case study. Pigs show an alternans feeding pattern, that is, a small peak of feed intake at the beginning of the day and a larger peak at the end of the day. We simulated the feeding behaviour of pigs over a 24h period. The simulation model contained mechanisms that regulate feeding behaviour of animals, including: processing of feed in the gastrointestinal tract, fluctuation in energy balance, circadian rhythms of melatonin and cortisol and motivational decision-making. From the interactions between these various processes, feeding patterns (e.g. feed intake, meal frequency, feeding rate) emerge. These feeding patterns, as well as patterns for the underlying mechanisms (e.g. energy expenditure), fitted empirical data well, indicating that our model contains relevant mechanisms. The circadian rhythms of cortisol and melatonin explained the alternans pattern of feeding in pigs. Additionally, the timing and amplitude of cortisol peaks affected the diurnal and nocturnal peaks in feed intake. Furthermore, our results suggest that circadian rhythms of other hormones, such as leptin and ghrelin, are less important in circadian regulation of feeding behaviour than previously thought. These results are relevant to animal species with a metabolic and endocrine system similar to that of pigs, such as humans. Moreover, the modelling approach to understand feeding behaviour can be applied to other animal species. Copyright © 2017 Elsevier Inc. All rights reserved.

How sleep problems contribute to simulator sickness: Preliminary results from a realistic driving scenario.

PubMed

Altena, Ellemarije; Daviaux, Yannick; Sanz-Arigita, Ernesto; Bonhomme, Emilien; de Sevin, Étienne; Micoulaud-Franchi, Jean-Arthur; Bioulac, Stéphanie; Philip, Pierre

2018-04-17

Virtual reality and simulation tools enable us to assess daytime functioning in environments that simulate real life as close as possible. Simulator sickness, however, poses a problem in the application of these tools, and has been related to pre-existing health problems. How sleep problems contribute to simulator sickness has not yet been investigated. In the current study, 20 female chronic insomnia patients and 32 female age-matched controls drove in a driving simulator covering realistic city, country and highway scenes. Fifty percent of the insomnia patients as opposed to 12.5% of controls reported excessive simulator sickness leading to experiment withdrawal. In the remaining participants, patients with insomnia showed overall increased levels of oculomotor symptoms even before driving, while nausea symptoms further increased after driving. These results, as well as the realistic simulation paradigm developed, give more insight on how vestibular and oculomotor functions as well as interoceptive functions are affected in insomnia. Importantly, our results have direct implications for both the actual driving experience and the wider context of deploying simulation techniques to mimic real life functioning, in particular in those professions often exposed to sleep problems. © 2018 European Sleep Research Society.

Self-report measures of distractibility as correlates of simulated driving performance.

PubMed

Kass, Steven J; Beede, Kristen E; Vodanovich, Stephen J

2010-05-01

The present study investigated the relationship between self-reported measures pertaining to attention difficulties and simulated driving performance while distracted. Thirty-six licensed drivers participated in a simulator driving task while engaged in a cell phone conversation. The participants completed questionnaires assessing their tendency toward boredom, cognitive failures, and behaviors associated with attention deficit and hyperactivity. Scores on these measures were significantly correlated with various driving outcomes (e.g., speed, lane maintenance, reaction time). Significant relationships were also found between one aspect of boredom proneness (i.e., inability to generate interest or concentrate) and self-reports of past driving behavior (moving violations). The current study may aid in the understanding of how individual differences in driver distractibility may contribute to unsafe driving behaviors and accident involvement. Additionally, such measures may assist in the identification of individuals at risk for committing driving errors due to being easily distracted. The benefits and limitations of conducting and interpreting simulation research are discussed. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Deficits in Attention and Visual Processing but not Global Cognition Predict Simulated Driving Errors in Drivers Diagnosed With Mild Alzheimer's Disease.

PubMed

Yamin, Stephanie; Stinchcombe, Arne; Gagnon, Sylvain

2016-06-01

This study sought to predict driving performance of drivers with Alzheimer's disease (AD) using measures of attention, visual processing, and global cognition. Simulated driving performance of individuals with mild AD (n = 20) was contrasted with performance of a group of healthy controls (n = 21). Performance on measures of global cognitive function and specific tests of attention and visual processing were examined in relation to simulated driving performance. Strong associations were observed between measures of attention, notably the Test of Everyday Attention (sustained attention; r = -.651, P = .002) and the Useful Field of View (r = .563, P = .010), and driving performance among drivers with mild AD. The Visual Object and Space Perception Test-object was significantly correlated with the occurrence of crashes (r = .652, P = .002). Tests of global cognition did not correlate with simulated driving outcomes. The results suggest that professionals exercise caution when extrapolating driving performance based on global cognitive indicators. © The Author(s) 2015.

Driving Simulator Performance of Veterans from the Iraq and Afghanistan Wars

DTIC Science & Technology

2013-01-01

abilities among this cohort who self-report poorer driving safety postdeployment. OIF/OEF Veterans (n = 25) and age- and education-matched civilian...more poorly on an objective evaluation of driving safety and that the presence of PTSD could be associated with worse performance on this standardized driving simulator assessment.

In-simulator training of driving abilities in a person with a traumatic brain injury.

PubMed

Gamache, Pierre-Luc; Lavallière, Martin; Tremblay, Mathieu; Simoneau, Martin; Teasdale, Normand

2011-01-01

This study reports the case of a 23-year-old woman (MC) who sustained a severe traumatic brain injury in 2004. After her accident, her driving license was revoked. Despite recovering normal neuropsychological functions in the following years, MC was unable to renew her license, failing four on-road evaluations assessing her fitness to drive. In hope of an eventual license renewal, MC went through an in-simulator training programme in the laboratory in 2009. The training programme aimed at improving features of MC's driving behaviour that were identified as being problematic in prior on-road evaluations. To do so, proper driving behaviour was reinforced via driving-specific feedback provided during the training sessions. After 25 sessions in the simulator (over a period of 4 months), MC significantly improved various components of her driving. Notably, compared to early sessions, later ones were associated with a reduced cognitive load, less jerky speed profiles when stopping at intersections and better vehicle control and positioning. A 1-year retention test showed most of these improvements were consistent. The learning principles underlying well conducted simulator-based education programmes have a strong scientific basis. A simulator training programme like this one represents a promising avenue for driving rehabilitation. It allows individuals without a driving license to practice and improve their skills in a safe and realistic environment.

Passive versus active engulfment: verdict from trajectory simulations of lunge-feeding fin whales Balaenoptera physalus

PubMed Central

Potvin, J.; Goldbogen, J. A.; Shadwick, R. E.

2009-01-01

Lunge-feeding in rorqual whales represents the largest biomechanical event on Earth and one of the most extreme feeding methods among aquatic vertebrates. By accelerating to high speeds and by opening their mouth to large gape angles, these whales generate the water pressure required to expand their mouth around a large volume of prey-laden water. Such large influx is facilitated by highly extensible ventral groove blubber (VGB) associated with the walls of the throat (buccal cavity). Based on the mechanical properties of this tissue, previous studies have assumed lunge-feeding to be an entirely passive process, where the flow-induced pressure driving the expansion of the VGB is met with little resistance. Such compliant engulfment would be facilitated by the compliant properties of the VGB that have been measured on dead specimens. However, adjoining the ventral blubber are several layers of well-developed muscle embedded with mechanoreceptors, thereby suggesting a capability to gauge the magnitude of engulfed water and use eccentric muscle action to control the flux of water into the mouth. An unsteady hydrodynamic model of fin whale lunge-feeding is presented here to test whether engulfment is exclusively passive and compliant or involves muscle action. The model is based on the explicit simulation of the engulfed water as it interacts with the buccal cavity walls of the whale, under different heuristically motivated cavity forces. Our results, together with their comparison with velocity data collected in the field, suggest that adult rorquals actively push engulfed water forward from the very onset of mouth opening in order to successfully complete a lunge. Interestingly, such an action involves a reflux of the engulfed mass rather than the oft-assumed rebound, which would occur mainly at the very end of a lunge sequence dominated by compliant engulfment. Given the great mass of the engulfed water, reflux creation adds a significant source of hydrodynamic drag to the lunge process, but with the benefit of helping to circumvent the problem of removing prey from baleen by enhancing the efficiency of cross-flow filtration after mouth closing. Reflux management for a successful lunge will therefore demand well-coordinated muscular actions of the tail, mouth and ventral cavity. PMID:19158011

NCI at Frederick Contributes to Feds Feed Families | Poster

Cancer.gov

Once again, NCI at Frederick participated in the annual Feds Feed Families event, which challenges federal workers to help knock out hunger with a food drive. This year, NIH collected 26,315 pounds of non-perishable goods, beating its goal of collecting 20,000 pounds. This includes over four tons of food that was collected at satellite locations, including NCI at Frederick. The food collected at NCI at Frederick was donated locally to the Frederick Rescue Mission. These donations help feed local families in need through the holiday season.

Neurocognitive Correlates of Young Drivers' Performance in a Driving Simulator.

PubMed

Guinosso, Stephanie A; Johnson, Sara B; Schultheis, Maria T; Graefe, Anna C; Bishai, David M

2016-04-01

Differences in neurocognitive functioning may contribute to driving performance among young drivers. However, few studies have examined this relation. This pilot study investigated whether common neurocognitive measures were associated with driving performance among young drivers in a driving simulator. Young drivers (19.8 years (standard deviation [SD] = 1.9; N = 74)) participated in a battery of neurocognitive assessments measuring general intellectual capacity (Full-Scale Intelligence Quotient, FSIQ) and executive functioning, including the Stroop Color-Word Test (cognitive inhibition), Wisconsin Card Sort Test-64 (cognitive flexibility), and Attention Network Task (alerting, orienting, and executive attention). Participants then drove in a simulated vehicle under two conditions-a baseline and driving challenge. During the driving challenge, participants completed a verbal working memory task to increase demand on executive attention. Multiple regression models were used to evaluate the relations between the neurocognitive measures and driving performance under the two conditions. FSIQ, cognitive inhibition, and alerting were associated with better driving performance at baseline. FSIQ and cognitive inhibition were also associated with better driving performance during the verbal challenge. Measures of cognitive flexibility, orienting, and conflict executive control were not associated with driving performance under either condition. FSIQ and, to some extent, measures of executive function are associated with driving performance in a driving simulator. Further research is needed to determine if executive function is associated with more advanced driving performance under conditions that demand greater cognitive load. Copyright © 2016 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Reduced Physical Fitness in Patients With Heart Failure as a Possible Risk Factor for Impaired Driving Performance

PubMed Central

Alosco, Michael L.; Penn, Marc S.; Spitznagel, Mary Beth; Cleveland, Mary Jo; Ott, Brian R.

2015-01-01

OBJECTIVE. Reduced physical fitness secondary to heart failure (HF) may contribute to poor driving; reduced physical fitness is a known correlate of cognitive impairment and has been associated with decreased independence in driving. No study has examined the associations among physical fitness, cognition, and driving performance in people with HF. METHOD. Eighteen people with HF completed a physical fitness assessment, a cognitive test battery, and a validated driving simulator scenario. RESULTS. Partial correlations showed that poorer physical fitness was correlated with more collisions and stop signs missed and lower scores on a composite score of attention, executive function, and psychomotor speed. Cognitive dysfunction predicted reduced driving simulation performance. CONCLUSION. Reduced physical fitness in participants with HF was associated with worse simulated driving, possibly because of cognitive dysfunction. Larger studies using on-road testing are needed to confirm our findings and identify clinical interventions to maximize safe driving. PMID:26122681

Effect of simulator training on driving after stroke: a randomized controlled trial.

PubMed

Akinwuntan, A E; De Weerdt, W; Feys, H; Pauwels, J; Baten, G; Arno, P; Kiekens, C

2005-09-27

Neurologically impaired persons seem to benefit from driving-training programs, but there is no convincing evidence to support this notion. The authors therefore investigated the effect of simulator-based training on driving after stroke. Eighty-three first-ever subacute stroke patients entered a 5-week 15-hour training program in which they were randomly allocated to either an experimental (simulator-based training) or control (driving-related cognitive tasks) group. Performance in off-road evaluations and an on-road test were used to assess the driving ability of subjects pre- and post-training. Outcome of an official predriving assessment administered 6 to 9 months poststroke was also considered. Both groups significantly improved in a visual and many neuropsychological evaluations and in the on-road test after training. There were no significant differences between both groups in improvements from pre- to post-training except in the "road sign recognition test" in which the experimental subjects improved more. Significant improvements in the three-class decision ("fit to drive," "temporarily unfit to drive," and "unfit to drive") were found in favor of the experimental group post-training. Academic qualification and overall disability together determined subjects that benefited most from the simulator-based driving training. Significantly more experimental subjects (73%) than control subjects (42%) passed the follow-up official predriving assessment and were legally allowed to resume driving. Simulator-based driving training improved driving ability, especially for well educated and less disabled stroke patients. However, the findings of the study may have been modified as a result of the large number of dropouts and the possibility of some neurologic recovery unrelated to training.

Infrastructure support for the UCF driving simulator

DOT National Transportation Integrated Search

2002-01-01

Last year, a proposal was funded to maintain the infrastructure of the UCF Driving Simulator Lab. It was designed to guarantee the long-term presence of support staff with proper expertise to maintain the operational effectiveness of the driving simu...

Some VTOL head-up display drive-law problems and solutions

NASA Technical Reports Server (NTRS)

Merrick, Vernon K.

1993-01-01

A piloted simulation test was conducted on the Ames Research Center's vertical motion simulator (VMS) in support of the Phase 2A flight test of NASA's V/STOL systems research aircraft (VSRA). During the simulation several problems were found with the head-up display (HUD) symbol drive laws and the flightpath synthesis. These problems and the solutions devised to solve them are described. Most of the resulting HUD drive-law changes were implemented during the simulation and their effectiveness was verified. Subsequently both the HUD symbol drive-law and flightpath-synthesis changes were implemented in the VSRA and tested successfully in the Phase 2A flight tests.

Relationships between frequency of driving under the influence of cannabis, self-reported reckless driving and risk-taking behavior observed in a driving simulator.

PubMed

Bergeron, Jacques; Paquette, Martin

2014-06-01

The role of cannabis consumption in traffic crashes is unclear and the causal link between cannabis and collisions is still to be demonstrated. While cannabis use is very likely to impair driving ability, there is as yet no overwhelming evidence that cannabis use in isolation contributes more to collisions than other characteristics inherent to cannabis users. As noted in a growing body of literature, individuals driving under the influence of cannabis (DUIC) seem to exhibit a general reckless driving style putting them at higher risk to be involved in traffic crashes. This study aims at investigating the relationship between self-reported DUIC and reckless driving by means of self-reported measures and direct observations made in a driving simulator. Participants (n=72) were required to be between 18 and 25 years of age, to hold a valid driver's license, and to drive at least twice a week. They completed standard driving simulation tasks recreating everyday on-road trivial conditions. Results show that people admitting that they commit more real-life dangerous driving behaviors reached higher maximum speed and demonstrated more reckless driving behaviors on the driving simulation tasks. Self-reported DUIC is associated with a risky driving style including a broad range of reckless on-road behaviors and support the problem driving behavior theory. Moreover, beyond confounding factors, both self-report DUIC and observed dangerous behaviors are associated with real-life traffic violations. Since DUIC appears to be related to an overall reckless style of driving, it is proposed that public safety policies should be more holistic, simultaneously targeting multiple on-road dangerous behaviors for intervention. Copyright © 2014 Elsevier B.V. All rights reserved.

Agribusiness Industry

DTIC Science & Technology

2007-01-01

corn supply has been used as animal feed and to produce high fructose corn syrup . In 2007, 25% of the US corn harvest is expected to be... high fructose corn syrup for existing corn . Thus, higher prices for corn caused by the ethanol demand is causing a rise in cost for high fructose ... corn syrup and animal feed, driving up consumer prices for chicken, pork, beef, and products, such as soft drinks, made

Doomed to collapse: Why Algerian steppe rangelands are overgrazed and some lessons to help land-use transitions.

PubMed

Martínez-Valderrama, Jaime; Ibáñez, Javier; Del Barrio, Gabriel; Alcalá, Francisco J; Sanjuán, Maria E; Ruiz, Alberto; Hirche, Azziz; Puigdefábregas, Juan

2018-02-01

This work illustrates the application of a simulation model to analyse how swiftly large-scale land-use changes can drive broad territories to collapse. In this sense, the economic needs of a population should not clash with the natural environment but rather be reconciled with it. Abundant literature deals with the integration of socioeconomic drivers, ecological aspects, farming management, and climatology related to Algerian rangeland degradation. The present study seeks to compare the time course of Alfa grass biomass and the livestock raised on these distinctive rangelands under two different land-use strategies. The traditional one has nomads as the main inhabitants of these lands. For centuries, their strategy for alleviating pressure on resources was to move from one area to other. The more recent sedentary land-use leads to overgrazing supported by the massive use of cheap supplemental feed. Additionally, the model was used as a platform to launch scenarios for sustainable land-use management under a competitive market-economy. A key finding for preserving grazing resources was the increment of supplemental feed prices, which is compatible with stocking rates higher than the historical ones. Copyright © 2017 Elsevier B.V. All rights reserved.

Black Hole Foraging: Feedback Drives Feeding

NASA Astrophysics Data System (ADS)

Dehnen, Walter; King, Andrew

2013-11-01

We suggest a new picture of supermassive black hole (SMBH) growth in galaxy centers. Momentum-driven feedback from an accreting hole gives significant orbital energy, but little angular momentum to the surrounding gas. Once central accretion drops, the feedback weakens and swept-up gas falls back toward the SMBH on near-parabolic orbits. These intersect near the black hole with partially opposed specific angular momenta, causing further infall and ultimately the formation of a small-scale accretion disk. The feeding rates into the disk typically exceed Eddington by factors of a few, growing the hole on the Salpeter timescale and stimulating further feedback. Natural consequences of this picture include (1) the formation and maintenance of a roughly toroidal distribution of obscuring matter near the hole; (2) random orientations of successive accretion disk episodes; (3) the possibility of rapid SMBH growth; (4) tidal disruption of stars and close binaries formed from infalling gas, resulting in visible flares and ejection of hypervelocity stars; (5) super-solar abundances of the matter accreting on to the SMBH; and (6) a lower central dark-matter density, and hence annihilation signal, than adiabatic SMBH growth implies. We also suggest a simple subgrid recipe for implementing this process in numerical simulations.

Assessment of driving-related performance in chronic whiplash using an advanced driving simulator.

PubMed

Takasaki, Hiroshi; Treleaven, Julia; Johnston, Venerina; Rakotonirainy, Andry; Haines, Andrew; Jull, Gwendolen

2013-11-01

Driving is often nominated as problematic by individuals with chronic whiplash associated disorders (WAD), yet driving-related performance has not been evaluated objectively. The purpose of this study was to test driving-related performance in persons with chronic WAD against healthy controls of similar age, gender and driving experience to determine if driving-related performance in the WAD group was sufficiently impaired to recommend fitness to drive assessment. Driving-related performance was assessed using an advanced driving simulator during three driving scenarios; freeway, residential and a central business district (CBD). Total driving duration was approximately 15min. Five driving tasks which could cause a collision (critical events) were included in the scenarios. In addition, the effect of divided attention (identify red dots projected onto side or rear view mirrors) was assessed three times in each scenario. Driving performance was measured using the simulator performance index (SPI) which is calculated from 12 measures. z-Scores for all SPI measures were calculated for each WAD subject based on mean values of the control subjects. The z-scores were then averaged for the WAD group. A z-score of ≤-2 indicated a driving failing grade in the simulator. The number of collisions over the five critical events was compared between the WAD and control groups as was reaction time and missed response ratio in identifying the red dots. Seventeen WAD and 26 control subjects commenced the driving assessment. Demographic data were comparable between the groups. All subjects completed the freeway scenario but four withdrew during the residential and eight during the CBD scenario because of motion sickness. All scenarios were completed by 14 WAD and 17 control subjects. Mean z-scores for the SPI over the three scenarios was statistically lower in the WAD group (-0.3±0.3; P<0.05) but the score was not below the cut-off point for safe driving. There were no differences in the reaction time and missed response ratio in divided attention tasks between the groups (All P>0.05). Assessment of driving in an advanced driving simulator for approximately 15min revealed that driving-related performance in chronic WAD was not sufficiently impaired to recommend the need for fitness to drive assessment. Copyright © 2013 Elsevier Ltd. All rights reserved.

Driving error and anxiety related to iPod mp3 player use in a simulated driving experience.

PubMed

Harvey, Ashley R; Carden, Randy L

2009-08-01

Driver distraction due to cellular phone usage has repeatedly been shown to increase the risk of vehicular accidents; however, the literature regarding the use of other personal electronic devices while driving is relatively sparse. It was hypothesized that the usage of an mp3 player would result in an increase in not only driving error while operating a driving simulator, but driver anxiety scores as well. It was also hypothesized that anxiety scores would be positively related to driving errors when using an mp3 player. 32 participants drove through a set course in a driving simulator twice, once with and once without an iPod mp3 player, with the order counterbalanced. Number of driving errors per course, such as leaving the road, impacts with stationary objects, loss of vehicular control, etc., and anxiety were significantly higher when an iPod was in use. Anxiety scores were unrelated to number of driving errors.

Evaluating driving performance of outpatients with Alzheimer disease.

PubMed

Cox, D J; Quillian, W C; Thorndike, F P; Kovatchev, B P; Hanna, G

1998-01-01

Alzheimer disease (AD) is a progressive disease, with multiple physiologic, psychologic, and social implications. A critical issue in its management is when to recommend restrictions on autonomous functioning, such as driving an automobile. This study evaluates driving performance of patients with AD and its relation to patient scores on the Mini-Mental State Exam (MMSE). This study compared 29 outpatients with probable AD with 21 age-matched control participants on an interactive driving simulator to determine how the two groups differed and how such differences related to mental status. Patients with AD (1) were less likely to comprehend and operate the simulator cognitively, (2) drove off the road more often, (3) spent more time driving considerably slower than the posted speed limit, (4) spent less time driving faster than the speed limit, (5) applied less brake pressure in stop zones, (6) spent more time negotiating left turns, and (7) drove more poorly overall. There were no observed differences between AD patients and the control group in terms of crossing the midline and driving speed variability. Among the AD patients, those who could not drive the simulator because of confusion and disorientation (n = 10) had lower MMSE scores and drove fewer miles annually. Those AD patients who had stopped driving also scored lower on their MMSE but did not perform more poorly on the driving simulator. Factor analysis revealed five driving factors associated with AD, explaining 93 percent of the variance. These five factors correctly classified 27 (85 percent) of 32 AD patients compared with the control group. Of the 15 percent who were improperly classified, there were three false positives (control participants misclassified as AD patients) and two false negatives (AD patients misclassified as control participants). The computed total driving score correlated significantly with MMSE scores (r = -.403, P = 0.011). Driving simulators can provide an objective means of assessing driving safety.

Test drivers in the Daimler-Benz driving simulator with drivers under diphenhydramine

DOT National Transportation Integrated Search

1991-01-01

The research project investigated the influence of diphenhydramine on the driving performance measured in the Daimler-Benz driving simulator. Test subjects were male students; 20 received a medium, and 20 received a high dosage of diphenhydramine. A ...

Name that tune: Mitigation of driver fatigue via a song naming game

DOE PAGES

Trumbo, Michael C.; Jones, Aaron P.; Robinson, Charles S. H.; ...

2017-09-18

Fatigued driving contributes to a substantial number of motor vehicle accidents each year. Music listening is often employed as a countermeasure during driving in order to mitigate the effects of fatigue. And though music listening has been established as a distractor in the sense that it increases cognitive load during driving, it is possible that increased cognitive load is desirable under particular circumstances. For instance, during situations that typically result in cognitive underload, such as driving in a low-traffic monotonous stretch of highway, it may be beneficial for cognitive load to increase, thereby necessitating allocation of greater cognitive resources tomore » the task of driving and attenuating fatigue. Here, we employed a song-naming game as a countermeasure to fatigued driving in a simulated monotonous environment. During the first driving session, we established that driving performance deteriorates in the absence of an intervention following 30 min of simulated driving. During the second session, we found that a song-naming game employed at the point of fatigue onset was an effective countermeasure, as reflected by simulated driving performance that met or exceeded fresh driving behavior and was significantly better relative to fatigued performance during the first driving session.« less

Name that tune: Mitigation of driver fatigue via a song naming game

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trumbo, Michael C.; Jones, Aaron P.; Robinson, Charles S. H.

Fatigued driving contributes to a substantial number of motor vehicle accidents each year. Music listening is often employed as a countermeasure during driving in order to mitigate the effects of fatigue. And though music listening has been established as a distractor in the sense that it increases cognitive load during driving, it is possible that increased cognitive load is desirable under particular circumstances. For instance, during situations that typically result in cognitive underload, such as driving in a low-traffic monotonous stretch of highway, it may be beneficial for cognitive load to increase, thereby necessitating allocation of greater cognitive resources tomore » the task of driving and attenuating fatigue. Here, we employed a song-naming game as a countermeasure to fatigued driving in a simulated monotonous environment. During the first driving session, we established that driving performance deteriorates in the absence of an intervention following 30 min of simulated driving. During the second session, we found that a song-naming game employed at the point of fatigue onset was an effective countermeasure, as reflected by simulated driving performance that met or exceeded fresh driving behavior and was significantly better relative to fatigued performance during the first driving session.« less

Predicting Motor Vehicle Collisions in a Driving Simulator in Young Adults Using the Useful Field of View Assessment.

PubMed

McManus, Benjamin; Cox, Molly K; Vance, David E; Stavrinos, Despina

2015-01-01

Being involved in motor vehicle collisions is the leading cause of death in 1- to 34-year-olds, and risk is particularly high in young adults. The Useful Field of View (UFOV) task, a cognitive measure of processing speed, divided attention, and selective attention, has been shown to be predictive of motor vehicle collisions in older adults, but its use as a predictor of driving performance in a young adult population has not been investigated. The present study examined whether UFOV was a predictive measure of motor vehicle collisions in a driving simulator in a young adult population. The 3-subtest version of UFOV (lower scores measured in milliseconds indicate better performance) was administered to 60 college students. Participants also completed an 11-mile simulated drive to provide driving performance metrics. Findings suggested that subtests 1 and 2 suffered from a ceiling effect. UFOV subtest 3 significantly predicted collisions in the simulated drive. Each 30 ms slower on the subtest was associated with nearly a 10% increase in the risk of a simulated collision. Post hoc analyses revealed a small partially mediating effect of subtest 3 on the relationship between driving experience and collisions. The selective attention component of UFOV subtest 3 may be a predictive measure of crash involvement in a young adult population. Improvements in selective attention may be the underlying mechanism in how driving experience improves driving performance.

Automated generation of virtual scenarios in driving simulator from highway design data.

DOT National Transportation Integrated Search

2010-09-01

In 2008, the Texas Transportation Institute (TTI) began using a desktop driving simulator made by Realtime : Technologies, Inc. This system comes with a library of different roadway segment types that can be pieced : together to create driving scenar...

Bus Driver Training Simulator Assessment

DOT National Transportation Integrated Search

1980-01-01

Simulation has become an increasingly important tool in driving research, highway research, and vehicle design. This report documents the results of an investigation into the feasibility of developing a driving simulator as a means of teaching safe d...

An Exploratory Investigation: Are Driving Simulators Appropriate to Teach Pre-Driving Skills to Young Adults with Intellectual Disabilities?

ERIC Educational Resources Information Center

Brooks, Johnell O.; Mossey, Mary E.; Tyler, Peg; Collins, James C.

2014-01-01

Research examining driver training for young adults with intellectual disabilities has been limited since the 1970s. The current pilot and exploratory study investigated teaching pre-driving skills (i.e. lane keeping and speed maintenance) to young adults with intellectual disabilities using an interactive driving simulator to provide dynamic and…

Safety evaluation of driver cognitive failures and driving errors on right-turn filtering movement at signalized road intersections based on Fuzzy Cellular Automata (FCA) model.

PubMed

Chai, Chen; Wong, Yiik Diew; Wang, Xuesong

2017-07-01

This paper proposes a simulation-based approach to estimate safety impact of driver cognitive failures and driving errors. Fuzzy Logic, which involves linguistic terms and uncertainty, is incorporated with Cellular Automata model to simulate decision-making process of right-turn filtering movement at signalized intersections. Simulation experiments are conducted to estimate the relationships between cognitive failures and driving errors with safety performance. Simulation results show Different types of cognitive failures are found to have varied relationship with driving errors and safety performance. For right-turn filtering movement, cognitive failures are more likely to result in driving errors with denser conflicting traffic stream. Moreover, different driving errors are found to have different safety impacts. The study serves to provide a novel approach to linguistically assess cognitions and replicate decision-making procedures of the individual driver. Compare to crash analysis, the proposed FCA model allows quantitative estimation of particular cognitive failures, and the impact of cognitions on driving errors and safety performance. Copyright © 2017 Elsevier Ltd. All rights reserved.

Classification of a Driver's cognitive workload levels using artificial neural network on ECG signals.

PubMed

Tjolleng, Amir; Jung, Kihyo; Hong, Wongi; Lee, Wonsup; Lee, Baekhee; You, Heecheon; Son, Joonwoo; Park, Seikwon

2017-03-01

An artificial neural network (ANN) model was developed in the present study to classify the level of a driver's cognitive workload based on electrocardiography (ECG). ECG signals were measured on 15 male participants while they performed a simulated driving task as a primary task with/without an N-back task as a secondary task. Three time-domain ECG measures (mean inter-beat interval (IBI), standard deviation of IBIs, and root mean squared difference of adjacent IBIs) and three frequencydomain ECG measures (power in low frequency, power in high frequency, and ratio of power in low and high frequencies) were calculated. To compensate for individual differences in heart response during the driving tasks, a three-step data processing procedure was performed to ECG signals of each participant: (1) selection of two most sensitive ECG measures, (2) definition of three (low, medium, and high) cognitive workload levels, and (3) normalization of the selected ECG measures. An ANN model was constructed using a feed-forward network and scaled conjugate gradient as a back-propagation learning rule. The accuracy of the ANN classification model was found satisfactory for learning data (95%) and testing data (82%). Copyright © 2016 Elsevier Ltd. All rights reserved.

Compact Feed Circuit with Quarter Wavelength Transmission Line Matrix Controlling Beams in Three Directions Including Boresight

NASA Astrophysics Data System (ADS)

Tsuji, Masatoshi

A compact feed circuit with a λ/4 transmission line matrix circuit for use in array antennas to control beams in three directions, including boresight, is presented. The feed circuit antenna is composed of five switches and λ/4 transmission lines, and the feeding matrix circuit yields phase differences of ±90° and 0°. The feed circuit can obtain a reliable output signal, as there is only a small degree of deviation of output signal with variations in the line width. The feed circuit is simulated, fabricated, and evaluated for ISM band, and the measured characteristics agree well with the results of the simulation. The size of feed circuit is 45 (H) × 48 (W) × 3 (T) mm.

Computerized Design and Generation of Gear Drives With a Localized Bearing Contact and a Low Level of Transmission Errors

NASA Technical Reports Server (NTRS)

Litvin, F.; Chen, J.; Seol, I.; Kim, D.; Lu, J.; Zhao, X.; Handschuh, R.

1996-01-01

A general approach developed for the computerized simulation of loaded gear drives is presented. In this paper the methodology used to localize the bearing contact, provide a parabolic function of transmission errors, and simulate meshing and contact of unloaded gear drives is developed. The approach developed is applied to spur and helical gears, spiral bevel gears, face-gear drives, and worm-gear drives with cylindrical worms.

Prediction of Fitness to Drive in Patients with Alzheimer's Dementia

PubMed Central

Piersma, Dafne; Fuermaier, Anselm B. M.; de Waard, Dick; Davidse, Ragnhild J.; de Groot, Jolieke; Doumen, Michelle J. A.; Bredewoud, Ruud A.; Claesen, René; Lemstra, Afina W.; Vermeeren, Annemiek; Ponds, Rudolf; Verhey, Frans; Brouwer, Wiebo H.; Tucha, Oliver

2016-01-01

The number of patients with Alzheimer’s disease (AD) is increasing and so is the number of patients driving a car. To enable patients to retain their mobility while at the same time not endangering public safety, each patient should be assessed for fitness to drive. The aim of this study is to develop a method to assess fitness to drive in a clinical setting, using three types of assessments, i.e. clinical interviews, neuropsychological assessment and driving simulator rides. The goals are (1) to determine for each type of assessment which combination of measures is most predictive for on-road driving performance, (2) to compare the predictive value of clinical interviews, neuropsychological assessment and driving simulator evaluation and (3) to determine which combination of these assessments provides the best prediction of fitness to drive. Eighty-one patients with AD and 45 healthy individuals participated. All participated in a clinical interview, and were administered a neuropsychological test battery and a driving simulator ride (predictors). The criterion fitness to drive was determined in an on-road driving assessment by experts of the CBR Dutch driving test organisation according to their official protocol. The validity of the predictors to determine fitness to drive was explored by means of logistic regression analyses, discriminant function analyses, as well as receiver operating curve analyses. We found that all three types of assessments are predictive of on-road driving performance. Neuropsychological assessment had the highest classification accuracy followed by driving simulator rides and clinical interviews. However, combining all three types of assessments yielded the best prediction for fitness to drive in patients with AD with an overall accuracy of 92.7%, which makes this method highly valid for assessing fitness to drive in AD. This method may be used to advise patients with AD and their family members about fitness to drive. PMID:26910535

Behavioural thermoregulation is highly repeatable and unaffected by digestive status in Agama atra.

PubMed

van Berkel, Jenna; Clusella-Trullas, Susana

2018-05-03

The precision and the extent of behavioral thermoregulation are likely to provide fitness benefits to ectotherms. Yet the factors driving variation in selected or preferred body temperature (T set ) and its usefulness as a proxy for optimal physiological temperature (T opt ) are still debated. Although T set is often conserved among closely related species, substantial variation at the individual, population, and species level has also been reported but repeatability (sensu the intra-class correlation coefficient, ICC) of T set is generally low. One factor that influences T set is feeding status, with fed reptiles typically showing higher T set , a process thought to aid meal digestion. Here using experiments simulating realistic ranges of feeding and fasting regimes in Agama atra, a heliothermic lizard from southern Africa, we test if T set and its repeatability under these two states significantly differ. Daily T set ranged from 33.7 to 38.4° C, with a mean (± SE) of 36.7 ± 0.1° C for fed and 36.6 ± 0.1° C for unfed individuals. Comparisons of repeatability showed that females tend to be more consistent in the selection of body temperature than males, but not significantly so regardless of feeding status. We report some of the highest repeatability estimates of T set to date (full range: 0.229 - 0.642), and that the weak positive effects of feeding status on T set detected here do not hinder obtaining relatively high repeatability estimates. In conclusion, one of the major prerequisites for natural selection, consistent among-individual variation, is present, making the adaptive significance of T set considerably more plausible. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Prey-mediated behavioral responses of feeding blue whales in controlled sound exposure experiments.

PubMed

Friedlaender, A S; Hazen, E L; Goldbogen, J A; Stimpert, A K; Calambokidis, J; Southall, B L

2016-06-01

Behavioral response studies provide significant insights into the nature, magnitude, and consequences of changes in animal behavior in response to some external stimulus. Controlled exposure experiments (CEEs) to study behavioral response have faced challenges in quantifying the importance of and interaction among individual variability, exposure conditions, and environmental covariates. To investigate these complex parameters relative to blue whale behavior and how it may change as a function of certain sounds, we deployed multi-sensor acoustic tags and conducted CEEs using simulated mid-frequency active sonar (MFAS) and pseudo-random noise (PRN) stimuli, while collecting synoptic, quantitative prey measures. In contrast to previous approaches that lacked such prey data, our integrated approach explained substantially more variance in blue whale dive behavioral responses to mid-frequency sounds (r2 = 0.725 vs. 0.14 previously). Results demonstrate that deep-feeding whales respond more clearly and strongly to CEEs than those in other behavioral states, but this was only evident with the increased explanatory power provided by incorporating prey density and distribution as contextual covariates. Including contextual variables increases the ability to characterize behavioral variability and empirically strengthens previous findings that deep-feeding blue whales respond significantly to mid-frequency sound exposure. However, our results are only based on a single behavioral state with a limited sample size, and this analytical framework should be applied broadly across behavioral states. The increased capability to describe and account for individual response variability by including environmental variables, such as prey, that drive foraging behavior underscores the importance of integrating these and other relevant contextual parameters in experimental designs. Our results suggest the need to measure and account for the ecological dynamics of predator-prey interactions when studying the effects of anthropogenic disturbance in feeding animals.

Hypopituitarism

MedlinePlus

... breast feeding, irregular or no menstrual periods, and hot flashes In men: loss of hair (on the face, or in the armpits or pubic area), decreased sex drive, infertility In children, problems with growth (including ...

Use driving simulator to synthesize the related vehicle specific power (VSP) for emissions and fuel consumption estimations.

DOT National Transportation Integrated Search

2016-01-01

Driving simulator approach can readily incorporate drivers real driving behaviors, the essential parameter that influences emissions. With regard to this, this research is proposed to test and validate the feasibility and applicability of the driv...

Control system to reduce the effects of friction in drive trains of continuous-path-positioning systems. [Patent application

DOEpatents

Green, W.L.

1980-12-01

An improved continuous-path-positioning servo-control system is provided for reducing the effects of friction arising at very low cutting speeds in the drive trains of numerically controlled cutting machines, and the like. The improvement comprises a feed forward network for altering the gain of the servo-control loop at low positioning velocities to prevent stick-slip movement of the cutting tool holder being positioned by the control system. The feed forward network shunts conventional lag-compensators in the control loop, or loops, so that the error signal used for positioning varies linearly when the value is small, but being limited for larger values. Thus, at higher positioning speeds there is little effect of the added component upon the control being achieved.

Sensitivity Analysis of the Integrated Medical Model for ISS Programs

NASA Technical Reports Server (NTRS)

Goodenow, D. A.; Myers, J. G.; Arellano, J.; Boley, L.; Garcia, Y.; Saile, L.; Walton, M.; Kerstman, E.; Reyes, D.; Young, M.

2016-01-01

Sensitivity analysis estimates the relative contribution of the uncertainty in input values to the uncertainty of model outputs. Partial Rank Correlation Coefficient (PRCC) and Standardized Rank Regression Coefficient (SRRC) are methods of conducting sensitivity analysis on nonlinear simulation models like the Integrated Medical Model (IMM). The PRCC method estimates the sensitivity using partial correlation of the ranks of the generated input values to each generated output value. The partial part is so named because adjustments are made for the linear effects of all the other input values in the calculation of correlation between a particular input and each output. In SRRC, standardized regression-based coefficients measure the sensitivity of each input, adjusted for all the other inputs, on each output. Because the relative ranking of each of the inputs and outputs is used, as opposed to the values themselves, both methods accommodate the nonlinear relationship of the underlying model. As part of the IMM v4.0 validation study, simulations are available that predict 33 person-missions on ISS and 111 person-missions on STS. These simulated data predictions feed the sensitivity analysis procedures. The inputs to the sensitivity procedures include the number occurrences of each of the one hundred IMM medical conditions generated over the simulations and the associated IMM outputs: total quality time lost (QTL), number of evacuations (EVAC), and number of loss of crew lives (LOCL). The IMM team will report the results of using PRCC and SRRC on IMM v4.0 predictions of the ISS and STS missions created as part of the external validation study. Tornado plots will assist in the visualization of the condition-related input sensitivities to each of the main outcomes. The outcomes of this sensitivity analysis will drive review focus by identifying conditions where changes in uncertainty could drive changes in overall model output uncertainty. These efforts are an integral part of the overall verification, validation, and credibility review of IMM v4.0.

Behavioral and Cardiovascular Responses to Frustration During Simulated Driving Tasks in Young Adults With and Without Attention Disorder Symptoms

PubMed Central

Oliver, Michele L.; Nigg, Joel T.; Cassavaugh, Nicholas D.; Backs, Richard W.

2015-01-01

Objective The present study examined the role of negative emotions on driving performance in relation to ADHD, by comparing young adults scoring high on measures of ADHD (n = 20) with a control group (n = 22). Method The authors used cardiorespiratory physiological measures, simulated driving behavior, and self-report to examine how participants with high and low ADHD symptoms responded to frustration and to determine how frustration affected simulated driving performance. Results Groups did not differ in operational driving skills, but participants with high ADHD symptoms reported more frustration and exhibited more impairment at the tactical level of driving performance than the controls. There was significant suppression of respiratory sinus arrhythmia from resting baseline during tasks, but it did not differ between groups during driving. Conclusion This article proposes that remedial driver training for ADHD populations should focus more on the control of negative emotions rather than on attention or fundamental driving skills. PMID:21490175

Can Youth with Autism Spectrum Disorder Use Virtual Reality Driving Simulation Training to Evaluate and Improve Driving Performance? An Exploratory Study

ERIC Educational Resources Information Center

Cox, Daniel J.; Brown, Timothy; Ross, Veerle; Moncrief, Matthew; Schmitt, Rose; Gaffney, Gary; Reeve, Ron

2017-01-01

Investigate how novice drivers with autism spectrum disorder (ASD) differ from experienced drivers and whether virtual reality driving simulation training (VRDST) improves ASD driving performance. 51 novice ASD drivers (mean age 17.96 years, 78% male) were randomized to routine training (RT) or one of three types of VRDST (8-12 sessions). All…

A Synergistic Transcriptional Regulation of Olfactory Genes Drives Blood-Feeding Associated Complex Behavioral Responses in the Mosquito Anopheles culicifacies.

PubMed

Das De, Tanwee; Thomas, Tina; Verma, Sonia; Singla, Deepak; Chauhan, Charu; Srivastava, Vartika; Sharma, Punita; Kumari, Seena; Tevatiya, Sanjay; Rani, Jyoti; Hasija, Yasha; Pandey, Kailash C; Dixit, Rajnikant

2018-01-01

Decoding the molecular basis of host seeking and blood feeding behavioral evolution/adaptation in the adult female mosquitoes may provide an opportunity to design new molecular strategy to disrupt human-mosquito interactions. Although there is a great progress in the field of mosquito olfaction and chemo-detection, little is known about the sex-specific evolution of the specialized olfactory system of adult female mosquitoes that enables them to drive and manage the complex blood-feeding associated behavioral responses. A comprehensive RNA-Seq analysis of prior and post blood meal olfactory system of An. culicifacies mosquito revealed a minor but unique change in the nature and regulation of key olfactory genes that may play a pivotal role in managing diverse behavioral responses. Based on age-dependent transcriptional profiling, we further demonstrated that adult female mosquito's chemosensory system gradually learned and matured to drive the host-seeking and blood feeding behavior at the age of 5-6 days. A time scale expression analysis of Odorant Binding Proteins (OBPs) unravels unique association with a late evening to midnight peak biting time. Blood meal-induced switching of unique sets of OBP genes and Odorant Receptors (Ors) expression coincides with the change in the innate physiological status of the mosquitoes. Blood meal follows up experiments further provide enough evidence that how a synergistic and concurrent action of OBPs-Ors may drive "prior and post blood meal" associated complex behavioral events. A dominant expression of two sensory appendages proteins (SAP-1 & SAP2) in the legs of An. culicifacies suggests that this mosquito species may draw an extra advantage of having more sensitive appendages than An. stephensi , an urban malarial vector in the Indian subcontinents. Finally, our molecular modeling analysis predicts crucial amino acid residues for future functional characterization of the sensory appendages proteins which may play a central role in regulating multiple behaviors of An. culicifacies mosquito. SIGNIFICANCE   Evolution and adaptation of blood feeding behavior not only favored the reproductive success of adult female mosquitoes but also make them important disease-transmitting vectors. An environmental exposure after emergence may favor the broadly tuned olfactory system of mosquitoes to drive complex behavioral responses. But, how these olfactory derived genetic factors manage female specific "pre and post" blood meal associated complex behavioral responses are not well known. Our findings suggest that a synergistic action of olfactory factors may govern an innate to prime learning strategy to facilitate rapid blood meal acquisition and downstream behavioral activities. A species-specific transcriptional profiling and an in-silico analysis predict that "sensory appendages protein" may be a unique target to design disorientation strategy against the mosquito Anopheles culicifacies .

Batu Pahat Driving Cycle for Light Duty Gasoline Engine

NASA Astrophysics Data System (ADS)

Zainul Abidin, Zainul Ameerul Ikhsan B.; Faisal Hushim, Mohd; Ahmad, Osman Bin

2017-08-01

Driving cycle is a series of data points that represents the vehicle speed versus time. Transient driving cycles involve many changes such as frequent speed changes during typical on-road driving condition [2]. Model driving cycles involve protracted periods at constant speeds. The Batu Pahat Driving Cycle (BPDC) developed to represent the driving pattern of people in a district of Batu Pahat. Based on this driving cycle, it will be a reference to other researchers to study about the gases emission release and fuel consumption by the vehicle on the dynamometer or automotive simulation based on this driving cycle. Existing driving cycles used such as the New European Driving Cycle (NEDC), the Federal Test Procedure (FTP-72/75, and Japan 10-15 Mode Cycle is not appropriate for Batu Pahat district because of different road conditions, driving habits and environmental of developed driving cycle countries are not same [2][14]. Batu Pahat drive cycle was developed for low-capacity gasoline engine under 150 cc and operating on urban roads, rural roads and road around Universiti Tun Hussein Onn. The importance of these driving cycle as the reference for other research to measure and do automotive simulation regarding fuel consumption and gas emission release from the motorcycle for these three type of driving cycle area. Another use for driving cycles is in vehicle simulations [3]. More specifically, they are used in propulsion system simulations to predict the performance of internal combustion engines, transmissions, electric drive systems, batteries, fuel cell systems, and similar components [18]. Data collection methods used in this study is the use of Global Positioning System (GPS). The results obtained are not similar to each other due to differences in congestion on data taken. From the driving cycle graph obtained, such as the average velocity, maximum velocity, the duration and Positive Acceleration Kinetic Energy (PKE) can be determined. In addition, the best driving cycle sample can be determined from the sum of error calculated. The least sum of error means the best driving cycle

Impact of sleep deprivation and obstructive sleep apnea syndrome on daytime vigilance and driving performance: a laboratory perspective.

PubMed

Pizza, F; Contardi, S; Mondini, S; Cirignotta, F

2012-01-01

To study the impact of sleepiness, a well-established cause of car accidents, on driving ability, we designed a 30-min monotonous simulated driving task. Our simulated driving task encompasses both primary vehicle control (standard deviation of lane position, crash occurrence) and secondary tasks (type and reaction times to divided attention tasks). Driving simulator data were correlated to subjective (state/trait) and objective (MSLT/MWT) sleepiness measures in healthy subjects undergoing sleep deprivation (SD) and in obstructive sleep apnea (OSAS) patients. SD induced severe sleepiness during nighttime, when state sleepiness increased while primary vehicle control ability worsened. After SD, driving ability decreased and was inversely correlated to subjective and objective sleepiness at MSLT. OSAS patients driving ability was well correlated to objective sleepiness, with inverse correlation to sleep propensity at the MSLT and even more strict relation with the ability to maintain wakefulness at the MWT. Sleepiness worsens driving ability in healthy subjects after SD and in OSAS patients. Driving ability correlates with subjective and objective sleepiness measures, in particular to the ability to maintain wakefulness.

Using driving simulators to assess driving safety.

PubMed

Boyle, Linda Ng; Lee, John D

2010-05-01

Changes in drivers, vehicles, and roadways pose substantial challenges to the transportation safety community. Crash records and naturalistic driving data are useful for examining the influence of past or existing technology on drivers, and the associations between risk factors and crashes. However, they are limited because causation cannot be established and technology not yet installed in production vehicles cannot be assessed. Driving simulators have become an increasingly widespread tool to understand evolving and novel technologies. The ability to manipulate independent variables in a randomized, controlled setting also provides the added benefit of identifying causal links. This paper introduces a special issue on simulator-based safety studies. The special issue comprises 25 papers that demonstrate the use of driving simulators to address pressing transportation safety problems and includes topics as diverse as neurological dysfunction, work zone design, and driver distraction. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Investigating cognitive ability and self-reported driving performance of post-stroke adults in a driving simulator.

PubMed

Blane, Alison; Falkmer, Torbjörn; Lee, Hoe C; Dukic Willstrand, Tania

2018-01-01

Background Safe driving is a complex activity that requires calibration. This means the driver can accurately assess the level of task demand required for task completion and can accurately evaluate their driving capability. There is much debate on the calibration ability of post-stroke drivers. Objectives The aim of this study was to assess the cognition, self-rated performance, and estimation of task demand in a driving simulator with post-stroke drivers and controls. Methods A between-groups study design was employed, which included a post-stroke driver group and a group of similarly aged older control drivers. Both groups were observed driving in two simulator-based driving scenarios and asked to complete the NASA Task Load Index (TLX) to assess their perceived task demand and self-rate their driving performance. Participants also completed a battery of psychometric tasks to assess attention and executive function, which was used to determine whether post-stroke cognitive impairment impacted on calibration. Results There was no difference in the amount of perceived task demand required to complete the driving task. Despite impairments in cognition, the post-stroke drivers were not more likely to over-estimate their driving abilities than controls. On average, the post-stroke drivers self-rated themselves more poorly than the controls and this rating was related to cognitive ability. Conclusion This study suggests that post-stroke drivers may be aware of their deficits and adjust their driving behavior. Furthermore, using self-performance measures alongside a driving simulator and cognitive assessments may provide complementary fitness-to-drive assessments, as well as rehabilitation tools during post-stroke recovery.

A simulation study of the effects of alcohol on driving performance in a Chinese population.

PubMed

Li, Y C; Sze, N N; Wong, S C; Yan, Wei; Tsui, K L; So, F L

2016-10-01

Driving under the influence of alcohol (DUIA) is a significant factor contributing to road traffic crashes, injuries, and fatalities. Although the effects of alcohol on driving performance are widely acknowledged, studies of the effects of alcohol impairment on driving performance and particularly on the control system of Chinese adults are rare. This study attempts to evaluate the effects of alcohol on the driving performance of Chinese adults using a driving simulator. A double-blind experimental study was conducted to evaluate the effects of alcohol impairment on the driving performance of 52 Chinese participants using a driving simulator. A series of simulated driving tests covering two driving modules, including emergency braking (EB) and following braking (FB), at 50km/h and 80km/h were performed. Linear mixed models were established to evaluate driving performance in terms of braking reaction time (BRT), the standard deviation of lateral position (SD-LANE), and the standard deviation of speed (SD-SPEED). Driving performance in terms of BRT and SD-LANE was highly correlated with the level of alcohol consumption, with a one-unit increase in breath alcohol concentration (BrAC) degrading BRT and SD-LANE by 0.3% and 0.2%, respectively. Frequent drinkers generally reacted faster in their BRT than less-frequent drinkers and non-drinkers by 10.2% and 30.6%, respectively. Moreover, alcohol impairment had varying effects on certain aspects of the human control system, and automatic action was less likely to be affected than voluntary action from a psychological viewpoint. The findings should be useful for planning and developing effective measures to combat drink driving in Chinese communities. Copyright © 2016 Elsevier Ltd. All rights reserved.

Name that tune: Mitigation of driver fatigue via a song naming game.

PubMed

Trumbo, Michael C; Jones, Aaron P; Robinson, Charles S H; Cole, Kerstan; Morrow, James D

2017-11-01

Fatigued driving contributes to a substantial number of motor vehicle accidents each year. Music listening is often employed as a countermeasure during driving in order to mitigate the effects of fatigue. Though music listening has been established as a distractor in the sense that it increases cognitive load during driving, it is possible that increased cognitive load is desirable under particular circumstances. For instance, during situations that typically result in cognitive underload, such as driving in a low-traffic monotonous stretch of highway, it may be beneficial for cognitive load to increase, thereby necessitating allocation of greater cognitive resources to the task of driving and attenuating fatigue. In the current study, we employed a song-naming game as a countermeasure to fatigued driving in a simulated monotonous environment. During the first driving session, we established that driving performance deteriorates in the absence of an intervention following 30min of simulated driving. During the second session, we found that a song-naming game employed at the point of fatigue onset was an effective countermeasure, as reflected by simulated driving performance that met or exceeded fresh driving behavior and was significantly better relative to fatigued performance during the first driving session. Copyright © 2017. Published by Elsevier Ltd.

Driving simulation for evaluation and rehabilitation of driving after stroke.

PubMed

Akinwuntan, Abiodun Emmanuel; Wachtel, Jerry; Rosen, Peter Newman

2012-08-01

Driving is an important activity of daily living. Loss of driving privileges can lead to depression, decreased access to medical care, and increased healthcare costs. The ability to drive is often affected after stroke. In approximately 30% of stroke survivors, it is clear from the onset that driving will no longer be possible. Approximately 33% of survivors will be able to return to driving with little or no retraining, and 35% will require driving-related rehabilitation before they can resume safe driving again. The ability to drive is not routinely evaluated after stroke, and there is no established rehabilitation program for poststroke driving. When driving evaluation does occur, it is not always clear which tests are the most salient for accurately assessing poststroke driving ability. Investigators have examined the efficacy of various methodologies to predict driving performance after stroke and have found mixed results, with each method having unique weaknesses, including poor predictive ability, poor face validity, poor sensitivity or specificity, and limited reliability. Here we review common models of driving to gain insight into why single-construct visual or cognitive off-road measures are inadequate for evaluating driving, a complex and dynamic activity that involves timely interaction of multiple motor, visual, cognitive, and perceptual skills. We also examine the potential for driving simulators to overcome the problems currently faced in the evaluation and rehabilitation of driving after stroke. Finally, we offer suggestions for the future direction of simulator-based poststroke driving evaluation and training. Copyright © 2012 National Stroke Association. Published by Elsevier Inc. All rights reserved.

System-wide Benefits of Intermeal Fasting by Autophagy.

PubMed

Martinez-Lopez, Nuria; Tarabra, Elena; Toledo, Miriam; Garcia-Macia, Marina; Sahu, Srabani; Coletto, Luisa; Batista-Gonzalez, Ana; Barzilai, Nir; Pessin, Jeffrey E; Schwartz, Gary J; Kersten, Sander; Singh, Rajat

2017-12-05

Autophagy failure is associated with metabolic insufficiency. Although caloric restriction (CR) extends healthspan, its adherence in humans is poor. We established an isocaloric twice-a-day (ITAD) feeding model wherein ITAD-fed mice consume the same food amount as ad libitum controls but at two short windows early and late in the diurnal cycle. We hypothesized that ITAD feeding will provide two intervals of intermeal fasting per circadian period and induce autophagy. We show that ITAD feeding modifies circadian autophagy and glucose/lipid metabolism that correlate with feeding-driven changes in circulating insulin. ITAD feeding decreases adiposity and, unlike CR, enhances muscle mass. ITAD feeding drives energy expenditure, lowers lipid levels, suppresses gluconeogenesis, and prevents age/obesity-associated metabolic defects. Using liver-, adipose-, myogenic-, and proopiomelanocortin neuron-specific autophagy-null mice, we mapped the contribution of tissue-specific autophagy to system-wide benefits of ITAD feeding. Our studies suggest that consuming two meals a day without CR could prevent the metabolic syndrome. Copyright © 2017 Elsevier Inc. All rights reserved.

[Effect of air-electric fields on driving and reaction patterns. Test subjects in the car driving simulator (author's transl)].

PubMed

Anselm, D; Danner, M; Kirmaier, N; König, H L; Müller-Limmroth, W; Reis, A; Schauerte, W

1977-06-10

In the relevant frequency range of about 10 Hertz cars can be considered very largely as Faraday cages and consequently as screens against air-electric fields. This may have a negative influence on driving and reaction patterns as a result. In an extensive investigation 48 subjects in a driving simulator were exposed to definite artificially produced air-electric fields. The self-rating of the performance and concentration of the subjects, reaction times and driving errors were determined. While the reaction times remained practically constant, the driving behavior of the subjects improved.

Peer Passenger Norms and Pressure: Experimental Effects on Simulated Driving Among Teenage Males.

PubMed

Bingham, C Raymond; Simons-Morton, Bruce G; Pradhan, Anuj K; Li, Kaigang; Almani, Farideh; Falk, Emily B; Shope, Jean T; Buckley, Lisa; Ouimet, Marie Claude; Albert, Paul S

2016-08-01

Serious crashes are more likely when teenage drivers have teenage passengers. One likely source of this increased risk is social influences on driving performance. This driving simulator study experimentally tested the effects of peer influence (i.e., risk-accepting compared to risk-averse peer norms reinforced by pressure) on the driving risk behavior (i.e., risky driving behavior and inattention to hazards) of male teenagers. It was hypothesized that peer presence would result in greater driving risk behavior (i.e., increased driving risk and reduced latent hazard anticipation), and that the effect would be greater when the peer was risk-accepting. Fifty-three 16- and 17-year-old male participants holding a provisional U.S., State of Michigan driver license were randomized to either a risk-accepting or risk-averse condition. Each participant operated a driving simulator while alone and separately with a confederate peer passenger. The simulator world included scenarios designed to elicit variation in driving risk behavior with a teen passenger present in the vehicle. Significant interactions of passenger presence (passenger present vs. alone) by risk condition (risk-accepting vs. risk-averse) were observed for variables measuring: failure to stop at yellow light intersections (Incident Rate Ratio (IRR)=2.16; 95% Confidence Interval [95CI]=1.06, 4.43); higher probability of overtaking (IRR=10.17; 95CI=1.43, 73.35); shorter left turn latency (IRR=0.43; 95CI=0.31,0.60); and, failure to stop at an intersection with an occluded stop sign (IRR=7.90; 95CI=2.06,30.35). In all cases, greater risky driving by participants was more likely with a risk-accepting passenger versus a risk-averse passenger present and a risk-accepting passenger present versus driving alone. Exposure of male teenagers to a risk-accepting confederate peer passenger who applied peer influence increased simulated risky driving behavior compared with exposure to a risk-averse confederate peer passenger or driving alone. These results are consistent with the contention that variability in teenage risky driving is in part explained by social influences.

Peer Passenger Norms and Pressure: Experimental Effects on Simulated Driving Among Teenage Males

PubMed Central

Bingham, C. Raymond; Simons-Morton, Bruce G.; Pradhan, Anuj K.; Li, Kaigang; Almani, Farideh; Falk, Emily B.; Shope, Jean T.; Buckley, Lisa; Ouimet, Marie Claude; Albert, Paul S.

2016-01-01

Objective Serious crashes are more likely when teenage drivers have teenage passengers. One likely source of this increased risk is social influences on driving performance. This driving simulator study experimentally tested the effects of peer influence (i.e., risk-accepting compared to risk-averse peer norms reinforced by pressure) on the driving risk behavior (i.e., risky driving behavior and inattention to hazards) of male teenagers. It was hypothesized that peer presence would result in greater driving risk behavior (i.e., increased driving risk and reduced latent hazard anticipation), and that the effect would be greater when the peer was risk-accepting. Methods Fifty-three 16- and 17-year-old male participants holding a provisional U.S., State of Michigan driver license were randomized to either a risk-accepting or risk-averse condition. Each participant operated a driving simulator while alone and separately with a confederate peer passenger. The simulator world included scenarios designed to elicit variation in driving risk behavior with a teen passenger present in the vehicle. Results Significant interactions of passenger presence (passenger present vs. alone) by risk condition (risk-accepting vs. risk-averse) were observed for variables measuring: failure to stop at yellow light intersections (Incident Rate Ratio (IRR)=2.16; 95% Confidence Interval [95CI]=1.06, 4.43); higher probability of overtaking (IRR=10.17; 95CI=1.43, 73.35); shorter left turn latency (IRR=0.43; 95CI=0.31,0.60); and, failure to stop at an intersection with an occluded stop sign (IRR=7.90; 95CI=2.06,30.35). In all cases, greater risky driving by participants was more likely with a risk-accepting passenger versus a risk-averse passenger present and a risk-accepting passenger present versus driving alone. Conclusions Exposure of male teenagers to a risk-accepting confederate peer passenger who applied peer influence increased simulated risky driving behavior compared with exposure to a risk-averse confederate peer passenger or driving alone. These results are consistent with the contention that variability in teenage risky driving is in part explained by social influences. PMID:27818610

Games for Traffic Education: An Experimental Study of a Game-Based Driving Simulator

ERIC Educational Resources Information Center

Backlund, Per; Engstrom, Henrik; Johannesson, Mikael; Lebram, Mikael

2010-01-01

In this article, the authors report on the construction and evaluation of a game-based driving simulator using a real car as a joystick. The simulator is constructed from off-the-shelf hardware and the simulation runs on open-source software. The feasibility of the simulator as a learning tool has been experimentally evaluated. Results are…

Comparison of a Virtual Older Driver Assessment with an On-Road Driving Test.

PubMed

Eramudugolla, Ranmalee; Price, Jasmine; Chopra, Sidhant; Li, Xiaolan; Anstey, Kaarin J

2016-12-01

To design a low-cost simulator-based driving assessment for older adults and to compare its validity with that of an on-road driving assessment and other measures of older driver risk. Cross-sectional observational study. Canberra, Australia. Older adult drivers (N = 47; aged 65-88, mean age 75.2). Error rate on a simulated drive with environment and scoring procedure matched to those of an on-road test. Other measures included participant age, simulator sickness severity, neuropsychological measures, and driver screening measures. Outcome variables included occupational therapist (OT)-rated on-road errors, on-road safety rating, and safety category. Participants' error rate on the simulated drive was significantly correlated with their OT-rated driving safety (correlation coefficient (r) = -0.398, P = .006), even after adjustment for age and simulator sickness (P = .009). The simulator error rate was a significant predictor of categorization as unsafe on the road (P = .02, sensitivity 69.2%, specificity 100%), with 13 (27%) drivers assessed as unsafe. Simulator error was also associated with other older driver safety screening measures such as useful field of view (r = 0.341, P = .02), DriveSafe (r = -0.455, P < .01), and visual motion sensitivity (r = 0.368, P = .01) but was not associated with memory (delayed word recall) or global cognition (Mini-Mental State Examination). Drivers made twice as many errors on the simulated assessment as during the on-road assessment (P < .001), with significant differences in the rate and type of errors between the two mediums. A low-cost simulator-based assessment is valid as a screening instrument for identifying at-risk older drivers but not as an alternative to on-road evaluation when accurate data on competence or pattern of impairment is required for licensing decisions and training programs. © 2016, Copyright the Authors Journal compilation © 2016, The American Geriatrics Society.

Stennis employees join Feds Feed Families effort

NASA Image and Video Library

2010-07-09

Cabrina Bell (l to r) and Jeanie Frederick with the Stennis Space Center Office of Human Capital help Hancock County Food Pantry representatives Edward Catone and Frank Manchester load collected food items July 9 as part of the 2010 Feds Feed Families campaign. The second annual national food drive was launched last month and involves federal agencies and employees across the country. Organizers hope to collect 1.2 million pounds of food items throughout the summer.

Simulated Fuel Economy and Emissions Performance during City and Interstate Driving for a Heavy-Duty Hybrid Truck

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daw, C. Stuart; Gao, Zhiming; Smith, David E.

2013-04-08

We compare simulated fuel economy and emissions for both conventional and hybrid class 8 heavy-duty diesel trucks operating over multiple urban and highway driving cycles. Both light and heavy freight loads were considered, and all simulations included full aftertreatment for NOx and particulate emissions controls. The aftertreatment components included a diesel oxidation catalyst (DOC), urea-selective catalytic NOx reduction (SCR), and a catalyzed diesel particulate filter (DPF). Our simulated hybrid powertrain was configured with a pre-transmission parallel drive, with a single electric motor between the clutch and gearbox. A conventional HD truck with equivalent diesel engine and aftertreatment was also simulatedmore » for comparison. Our results indicate that hybridization can significantly increase HD fuel economy and improve emissions control in city driving. However, there is less potential hybridization benefit for HD highway driving. A major factor behind the reduced hybridization benefit for highway driving is that there are fewer opportunities to utilize regenerative breaking. Our aftertreatment simulations indicate that opportunities for passive DPF regeneration are much greater for both hybrid and conventional trucks during highway driving due to higher sustained exhaust temperatures. When passive DPF regeneration is extensively utilized, the fuel penalty for particulate control is virtually eliminated, except for the 0.4%-0.9% fuel penalty associated with the slightly higher exhaust backpressure.« less

Night driving simulation in a randomized prospective comparison of Visian toric implantable collamer lens and conventional PRK for moderate to high myopic astigmatism.

PubMed

Schallhorn, Steven; Tanzer, David; Sanders, Donald R; Sanders, Monica; Brown, Mitch; Kaupp, Sandor E

2010-05-01

To compare changes in simulated night driving performance after Visian Toric Implantable Collamer Lens (TICL; STAAR Surgical) implantation and photorefractive keratectomy (PRK) for the correction of moderate to high myopic astigmatism. This prospective, randomized study consisted of 43 eyes implanted with the TICL (20 bilateral cases) and 45 eyes receiving conventional PRK (VISX Star S3 excimer laser) with mitomycin C (22 bilateral cases) for moderate to high myopia (-6.00 to -20.00 diopters[D] sphere) measured at the spectacle plane and 1.00 to 4.00 D of astigmatism. As a substudy, 27 eyes of 14 TICL patients and 41 eyes of 21 PRK patients underwent a simulated night driving test. The detection and identification distances of road signs and hazards with the Night Driving Simulator (Vision Sciences Research Corp) were measured with and without a glare source before and 6 months after each procedure. No significant difference was noted in the pre- to postoperative Night Driving Simulator in detection distances with and without the glare source between the TICL and PRK groups. The differences in identification distances without glare were significantly better for business and traffic road signs and pedestrian hazards in the TICL group relative to the PRK group whereas with glare, only the pedestrian hazards were significantly better. A clinically relevant change of Night Driving Simulator performance (>0.5 seconds change in ability to identify tasks postoperatively) was significantly better in the TICL group (with and without glare) for all identification tasks. The TICL performed better than conventional PRK in the pre- to postoperative Night Driving Simulator testing with and without a glare source present. Copyright 2010, SLACK Incorporated.

Validating a driving simulator using surrogate safety measures.

PubMed

Yan, Xuedong; Abdel-Aty, Mohamed; Radwan, Essam; Wang, Xuesong; Chilakapati, Praveen

2008-01-01

Traffic crash statistics and previous research have shown an increased risk of traffic crashes at signalized intersections. How to diagnose safety problems and develop effective countermeasures to reduce crash rate at intersections is a key task for traffic engineers and researchers. This study aims at investigating whether the driving simulator can be used as a valid tool to assess traffic safety at signalized intersections. In support of the research objective, this simulator validity study was conducted from two perspectives, a traffic parameter (speed) and a safety parameter (crash history). A signalized intersection with as many important features (including roadway geometries, traffic control devices, intersection surroundings, and buildings) was replicated into a high-fidelity driving simulator. A driving simulator experiment with eight scenarios at the intersection were conducted to determine if the subjects' speed behavior and traffic risk patterns in the driving simulator were similar to what were found at the real intersection. The experiment results showed that speed data observed from the field and in the simulator experiment both follow normal distributions and have equal means for each intersection approach, which validated the driving simulator in absolute terms. Furthermore, this study used an innovative approach of using surrogate safety measures from the simulator to contrast with the crash analysis for the field data. The simulator experiment results indicated that compared to the right-turn lane with the low rear-end crash history record (2 crashes), subjects showed a series of more risky behaviors at the right-turn lane with the high rear-end crash history record (16 crashes), including higher deceleration rate (1.80+/-1.20 m/s(2) versus 0.80+/-0.65 m/s(2)), higher non-stop right-turn rate on red (81.67% versus 57.63%), higher right-turn speed as stop line (18.38+/-8.90 km/h versus 14.68+/-6.04 km/h), shorter following distance (30.19+/-13.43 m versus 35.58+/-13.41 m), and higher rear-end probability (9/59=0.153 versus 2/60=0.033). Therefore, the relative validity of driving simulator was well established for the traffic safety studies at signalized intersections.

Sex Differences in the Effects of Marijuana on Simulated Driving Performance†

PubMed Central

Anderson, Beth M.; Rizzo, Matthew; Block, Robert I.; Pearlson, Godfrey D.; O'Leary, Daniel S.

2011-01-01

In the United States, one in six teenagers has driven under the influence of marijuana. Driving under the influence of marijuana and alcohol is equally prevalent, despite the fact that marijuana use is less common than alcohol use. Much of the research examining the effects of marijuana on driving performance was conducted in the 1970s and led to equivocal findings. During that time, few studies included women and driving simulators were rudimentary. Further, the potency of marijuana commonly used recreationally has increased. This study examined sex differences in the acute effects of marijuana on driving performance using a realistic, validated driving simulator. Eighty-five subjects (n = 50 males, 35 females) participated in this between-subjects, double-blind, placebo controlled study. In addition to an uneventful, baseline segment of driving, participants were challenged with collision avoidance and distracted driving scenarios. Under the influence of marijuana, participants decreased their speed and failed to show expected practice effects during a distracted drive. No differences were found during the baseline driving segment or collision avoidance scenarios. No differences attributable to sex were observed. This study enhances the current literature by identifying distracted driving and the integration of prior experience as particularly problematic under the influence of marijuana. PMID:20464803

Effects of two doses of methylphenidate on simulator driving performance in adults with attention deficit hyperactivity disorder.

PubMed

Barkley, Russell A; Murphy, Kevin R; O'Connell, Trisha; Connor, Daniel F

2005-01-01

Numerous studies have documented an increased frequency of vehicular crashes, traffic citations, driving performance deficits, and driving-related cognitive impairments in teens and adults with attention deficit hyperactivity disorder. The present study evaluated the effects of two single, acute doses of methylphenidate (10 and 20 mg) and a placebo on the driving performance of 53 adults with ADHD (mean age=37 years, range=18-65) using a virtual reality driving simulator, examiner and self-ratings of simulator performance, and a continuous performance test (CPT) to evaluate attention and inhibition. A double-blind, drug-placebo, within-subjects crossover design was used in which all participants were tested at baseline and then experienced all three drug conditions. A significant beneficial effect for the high dose of medication was observed on impulsiveness on CPT, variability of steering in the standard driving course, and driving speed during the obstacle course. A beneficial effect of the low dose of medication also was evident on turn signal use during the standard driving course. An apparent practice effect was noted on some of the simulator measures between the baseline and subsequent testing sessions that may have interacted with and thereby obscured drug effects on those measures. The results, when placed in the context of prior studies of stimulants on driving performance, continue to recommend their clinical use as one means of reducing the driving risks in ADHD teens and adults. Given the significantly higher risk of adverse driving outcomes associated with ADHD, industry needs to better screen for ADHD among employees who drive as part of employment so as to improve safety and reduce costs. Use of stimulants to treat the adult ADHD driver may reduce safety risks.

Advanced Simulator for Combat, Transport Vehicles, Submarines, Vessels, Airplanes and Helicopters

DTIC Science & Technology

2004-10-01

simulation experiments. 3.1 Road vehicles - lane change test In order to evaluate the driving dynamics and also the driving safety of road vehicles...8] L.D. Chen, Y. Papelis, G. Watson, D. Solis. NADS at the University of Iowa: A Tool for Driving Safety Research, In Proceedings of 1st Human

[Effects of marijuana and amphetamine (and its derivatives on driving performance based on the driving simulator studies].

PubMed

Drabek, Marcin; Andysz, Aleksandra

2011-01-01

This article presents the results of the driving simulator studies of the effects of marijuana and amphetamines on driving performance. The majority of these studies have been focused on identifying the impact of the tested substances on cognitive and psychomotor functions. Most of the findings on marijuana reveal its modest effect on driving ability that increases with the increasing frequency of its use and when used in conjuction with other drugs and alcohol. Similarly, small doses of amphetamines can cause a positive stimulating effect, improving certain cognitive functions, such as vigilance, but it decreases when they are overused and combined with alcohol. The results of the research on drivers' behavior under the influence of amphetamines also indicate deficits in their cognitive functions and tendency to recklessness on the road. The authors also discuss strong and weak points of simulation studies of the effects of psychoactive substances on the driving ability. An attempt was also made to clarify certain ambiguities, which occur in this field of research. A central role of the ethical and methodological limitations of simulation studies were discussed as well.

H1 antihistamines and driving.

PubMed

Popescu, Florin Dan

2008-01-01

Driving performances depend on cognitive, psychomotor and perception functions. The CNS adverse effects of some H1 antihistamines can alter the patient ability to drive. Data from studies using standardized objective cognitive and psychomotor tests (Choice Reaction Time, Critical Flicker Fusion. Digital Symbol Substitution Test), functional brain imaging (Positron Emission Tomography, functional Magnetic Resonance Imaging), neurophysiological studies (Multiple Sleep Latency Test, auditory and visual evoked potentials), experimental simulated driving (driving simulators) and real driving studies (the Highway Driving Test, with the evaluation of the Standard Deviation Lateral Position, and the Car Following Test, with the measurement of the Brake Reaction Time) must be discussed in order to classify a H1 antihistamine as a true non-sedating one.

H1 antihistamines and driving

PubMed Central

Florin-Dan, Popescu

2008-01-01

Driving performances depend on cognitive, psychomotor and perception functions. The CNS adverse effects of some H1 antihistamines can alter the patient ability to drive. Data from studies using standardized objective cognitive and psychomotor tests (Choice Reaction Time, Critical Flicker Fusion, Digital Symbol Substitution Test), functional brain imaging (Positron Emission Tomography, functional Magnetic Resonance Imaging), neurophysiological studies (Multiple Sleep Latency Test, auditory and visual evoked potentials), experimental simulated driving (driving simulators) and real driving studies (the Highway Driving Test, with the evaluation of the Standard Deviation Lateral Position, and the Car Following Test, with the measurement of the Brake Reaction Time) must be discussed in order to classify a H1 antihistamine as a true non-sedating one. PMID:20108503

Design process for applying the nonlocal thermal transport iSNB model to a Polar-Drive ICF simulation

NASA Astrophysics Data System (ADS)

Cao, Duc; Moses, Gregory; Delettrez, Jacques; Collins, Timothy

2014-10-01

A design process is presented for the nonlocal thermal transport iSNB (implicit Schurtz, Nicolai, and Busquet) model to provide reliable nonlocal thermal transport in polar-drive ICF simulations. Results from the iSNB model are known to be sensitive to changes in the SNB ``mean free path'' formula, and the latter's original form required modification to obtain realistic preheat levels. In the presented design process, SNB mean free paths are first modified until the model can match temperatures from Goncharov's thermal transport model in 1D temperature relaxation simulations. Afterwards the same mean free paths are tested in a 1D polar-drive surrogate simulation to match adiabats from Goncharov's model. After passing the two previous steps, the model can then be run in a full 2D polar-drive simulation. This research is supported by the University of Rochester Laboratory for Laser Energetics.

Application of Biological Simulation Models in Estimating Feed Efficiency of Finishing Steers

USDA-ARS?s Scientific Manuscript database

Data on individual daily feed intake, bi-weekly BW, and carcass composition were obtained on 1,212 crossbred steers. Within animal regressions of cumulative feed intake and BW on linear and quadratic days on feed were used to quantify initial and ending BW, average daily feed intake (OFI) and ADG o...

Driving Responses of Older and Younger Drivers in a Driving Simulator

PubMed Central

Fildes, Brian; Charlton, Judith; Muir, Carlyn; Koppel, Sjaanie

2007-01-01

This paper reports the findings of a study of younger and older driver behaviour to hazardous traffic manoeuvres in a driving simulator. Hazardous situations on a highway and residential drive were studied and drivers’ vision and vehicle performance responses were collected. While all drivers were able to avoid crashes, the finding that older drivers were consistently slower to fixate hazardous stimuli in the driving environment and were slower to respond presents a potentially serious road safety concern. Further research is warranted, especially under conditions of increasing traffic complexity. PMID:18184513

A simulator study of the combined effects of alcohol and marihuana on driving behavior--phase II

DOT National Transportation Integrated Search

1983-02-01

Author's abstract: The study described in this report investigated the effects of alcohol and marihuana, alone and in combination, on driver performance and behavior in a fully interactive driving simulator. The simulator provided the driver a comple...

Effects of Armodafinil on Simulated Driving and Self-Report Measures in Obstructive Sleep Apnea Patients prior to Treatment with Continuous Positive Airway Pressure

PubMed Central

Kay, Gary G.; Feldman, Neil

2013-01-01

Study Objectives: Obstructive sleep apnea (OSA) has been associated with an increased risk of motor vehicle crashes. This driving risk can be reduced (≥ 50%) by treatment with continuous positive airway pressure (CPAP). However residual excessive daytime sleepiness (EDS) can persist for some patients who regularly use CPAP. The current study was designed to assess the effect of armodafinil on simulated driving performance and subsequent CPAP treatment compliance in newly diagnosed OSA patients with EDS during a 2-week “waiting period” prior to initiation of CPAP. Methods: Sixty-nine newly diagnosed OSA patients, awaiting CPAP therapy, were randomized (1:1) to placebo or armodafinil (150 mg/day) treatment. Simulated driving tests and self-report measures were completed at baseline, after 2 weeks of drug treatment, and following 6 weeks of CPAP treatment. CPAP compliance was evaluated at the end of 6 weeks of CPAP. Results: Compared to placebo, armodafinil improved simulated driving safety performance in OSA patients awaiting CPAP therapy (p = 0.03). Improvement was seen in lane position deviation (p = 0.002) and number of lane excursions (p = 0.02). Improvement was also observed on measures of sleepiness using the Epworth Sleepiness Scale (ESS) and sleep related quality of life. Following 6 weeks of CPAP, there was also significant improvement observed on multiple measures of simulated driving performance. CPAP compliance did not differ between armodafinil-treated and placebo-treated patients (p = 0.80). Conclusions: Armodafinil was found to improve simulated driving performance in OSA patients with EDS prior to initiation of CPAP. Treatment with armodafinil showed no effect on subsequent CPAP compliance. Citation: Kay GG; Feldman N. Effects of armodafinil on simulated driving and self-report measures in obstructive sleep apnea patients prior to treatment with continuous positive airway pressure. J Clin Sleep Med 2013;9(5):445-454. PMID:23674935

Understanding Resonance Graphs Using Easy Java Simulations (EJS) and Why We Use EJS

ERIC Educational Resources Information Center

Wee, Loo Kang; Lee, Tat Leong; Chew, Charles; Wong, Darren; Tan, Samuel

2015-01-01

This paper reports a computer model simulation created using Easy Java Simulation (EJS) for learners to visualize how the steady-state amplitude of a driven oscillating system varies with the frequency of the periodic driving force. The simulation shows (N = 100) identical spring-mass systems being subjected to (1) a periodic driving force of…

Using alcohol intoxication goggles (Fatal Vision® goggles) to detect alcohol related impairment in simulated driving.

PubMed

McCartney, Danielle; Desbrow, Ben; Irwin, Christopher

2017-01-02

Fatal vision goggles (FVGs) are image-distorting equipment used within driver education programs to simulate alcohol-related impairment. However, there is no empirical evidence comparing the behavioral effects associated with wearing FVGs to alcohol intoxication. The purpose of this study was to determine the validity of FVGs in producing alcohol-related impairment in simulated driving. Twenty-two healthy males (age: 23 ± 3 years, mean ± SD) participated in a placebo-controlled crossover design study involving 4 experimental trials. In each trial, participants completed a baseline level simulated driving task followed by an experimental driving task, involving one of 4 treatments: (1) a dose of alcohol designed to elicit 0.080% breath alcohol concentration (BrAC; AB), (2) an alcohol placebo beverage (PB), (3) FVG (estimated % blood alcohol concentration [BAC] 0.070-0.100+), and (4) placebo goggles (PGs). The driving tasks included 3 separate scenarios lasting ∼5 min each; these were a simple driving scenario, a complex driving scenario, and a hazard perception driving scenario. Selected lateral control parameters (standard deviation of lane position [SDLP]; total number of lane crossings [LCs]) and longitudinal control parameters (average speed; standard deviation of speed [SDSP]; distance headway; minimum distance headway) were monitored during the simple and complex driving scenarios. Latency to 2 different stimuli (choice reaction time [CRT]) was tested in the hazard perception driving scenario. Subjective ratings of mood and attitudes toward driving were also provided during each of the trials. Neither placebo treatment influenced simulated driving performance. Mean BrAC was 0.060 ± 0.010% at the time of driving on the AB trial. Lateral control: In the simple driving scenario, SDLP and LC were not affected under any of the experimental treatments. However, in the complex driving scenario, significantly greater SDLP was observed on both the FVG and AB trials compared to their respective baseline drives. LC increased significantly from baseline on the AB trial only. Longitudinal control: Speed was not affected by any of the experimental treatments; however, SDSP increased significantly from baseline on the FVG trial. A significant reduction in distance headway and minimum distance headway was detected on the FVG trial compared to baseline. Hazard perception: Neither AB nor FVG trials were influential on CRT. Subjective mood ratings were significantly altered on the AB and FVG trials compared to baseline and placebo conditions. Participants reported reduced willingness and ability to drive under the active treatments (AB and FVG) than the placebo treatments (PB and PG). FVGs may have some utility in replicating alcohol-related impairment on specific driving performance measurements. Hence, the equipment may offer an alternative approach to researching the impact of alcohol intoxication on simulated driving performance among populations where the provision of alcohol would otherwise be unethical (e.g., prelicensed drivers).

Alcohol, Drugs and Driving: Implications for Evaluating Driver Impairment

PubMed Central

Brown, Timothy; Milavetz, Gary; Murry, Daryl J.

2013-01-01

Impaired driving is a significant traffic safety problem, and alcohol and drugs taken before driving contribute substantially to this problem. With the increase in use of prescription medication and the decriminalization of some drugs, it has become increasingly important to understand the manifestation of driver impairment. Building upon previous alcohol research conducted at the National Advanced Driving Simulator (NADS), this study enrolled commercial bus drivers to evaluate the effect of triazolam on driving performance to assess difference between placebo, 0.125, and 0.25 mg doses in a randomized and double-blind design. On each of three randomized visits, subjects drove a simulator scenario that had previously been used to demonstrate effects of alcohol on driving performance. Plasma triazolam levels were obtained before the simulator drive. The protocol included participants receiving study medication and placebo over a 3-week period of time one to two weeks apart. The simulator drives used for this analysis occurred approximately 140 minutes after dosing—after the subjects had completed four bus simulator drives and neuropsychological tests over a 2-hour period of time surrounding dosing. The driving scenario contained representative situations on three types of roadways (urban, freeway, and rural) under nighttime driving conditions. Lane keeping performance (ability to drive straight in the lane) under the three doses of triazolam demonstrates that at the 0.25 mg dose, statistically significant effects on performance are observed, but no effects are found at the 0.125 mg level when testing at this time period after dosing. This differs from the effects of alcohol, which shows impairing effects at a 0.05% blood alcohol concentration (BAC) and a greater effect at 0.10% BAC. These results demonstrate the importance of understanding how different types of drugs affect driving performance in realistic driving environments. Although some compounds may have an effect that correlates linearly to dosage, that is not always the case. An understanding of these differences and how they vary across driving tasks is essential to developing a robust evaluation protocol that can accurately describe the effects of a wide variety of drugs on driver impairment. This information can be used to reduce the risk of deleterious effects of therapeutic medications while ensuring their safe and beneficial use. PMID:24406943

Assessment of wheelchair driving performance in a virtual reality-based simulator

PubMed Central

Mahajan, Harshal P.; Dicianno, Brad E.; Cooper, Rory A.; Ding, Dan

2013-01-01

Objective To develop a virtual reality (VR)-based simulator that can assist clinicians in performing standardized wheelchair driving assessments. Design A completely within-subjects repeated measures design. Methods Participants drove their wheelchairs along a virtual driving circuit modeled after the Power Mobility Road Test (PMRT) and in a hallway with decreasing width. The virtual simulator was displayed on computer screen and VR screens and participants interacted with it using a set of instrumented rollers and a wheelchair joystick. Driving performances of participants were estimated and compared using quantitative metrics from the simulator. Qualitative ratings from two experienced clinicians were used to estimate intra- and inter-rater reliability. Results Ten regular wheelchair users (seven men, three women; mean age ± SD, 39.5 ± 15.39 years) participated. The virtual PMRT scores from the two clinicians show high inter-rater reliability (78–90%) and high intra-rater reliability (71–90%) for all test conditions. More research is required to explore user preferences and effectiveness of the two control methods (rollers and mathematical model) and the display screens. Conclusions The virtual driving simulator seems to be a promising tool for wheelchair driving assessment that clinicians can use to supplement their real-world evaluations. PMID:23820148

SRS Computer Animation and Drive Train System

NASA Technical Reports Server (NTRS)

Arthun, Daniel; Schachner, Christian

2001-01-01

The spinning rocket simulator (SRS) is an ongoing project at Oral Roberts University. The goal of the SRS is to gather crucial data concerning a spinning rocket under thrust for the purpose of analysis and correction of the coning motion experienced by this type of spacecraft maneuver. The computer animation simulates a virtual, scale model of the component of the SRS that represents the spacecraft itself. This component is known as the (VSM), or virtual spacecraft model. During actual physical simulation, this component of the SRS will experience a coning. The goal of the animation is to cone the VSM within that range to accurately represent the motion of the actual simulator. The drive system of the SRS is the apparatus that turns the actual simulator. It consists of a drive motor, motor mount and chain to power the simulator into motion. The motor mount is adjustable and rigid for high torque application. A digital stepper motor controller actuates the main drive motor for linear acceleration. The chain transfers power from the motor to the simulator via sprockets on both ends.

A High Fidelity Driving Simulator as a Tool for Design and Evaluation of Highway Infrastructure Upgrades

DOT National Transportation Integrated Search

2007-05-01

A rapid prototyping approach was used in the driving simulation laboratory at the Western Transportation Institute (WTI) to simulate approximately 22 miles of US 191 between the Big Sky Resort community and the northern mouth of the Gallatin Canyon. ...

Microscopic Car Modeling for Intelligent Traffic and Scenario Generation in the UCF Driving Simulator : Year 2

DOT National Transportation Integrated Search

2000-01-01

A multi-year project was initiated to introduce autonomous vehicles in the University of Central Florida (UCF) Driving Simulator for real-time interaction with the simulator vehicle. This report describes the progress during the second year. In the f...

Does Simulator Sickness Impair Learning Decision Making While Driving a Police Vehicle? (Le mal du simulateur: un frein à l'apprentissage de la prise de décision en conduite d'un véhicule de police?)

ERIC Educational Resources Information Center

Paquette, Eve; Bélanger, Danielle-Claude

2015-01-01

The use of driving simulators is an innovation for police training in Quebec. There are some issues related to their impact on training objectives. This article presents the results of a study involving 71 police cadets who participated in six training sessions with a driving simulator. The training sessions were designed for developing the…

Numerically robust and efficient nonlocal electron transport in 2D DRACO simulations

NASA Astrophysics Data System (ADS)

Cao, Duc; Chenhall, Jeff; Moses, Greg; Delettrez, Jacques; Collins, Tim

2013-10-01

An improved implicit algorithm based on Schurtz, Nicolai and Busquet (SNB) algorithm for nonlocal electron transport is presented. Validation with direct drive shock timing experiments and verification with the Goncharov nonlocal model in 1D LILAC simulations demonstrate the viability of this efficient algorithm for producing 2D lagrangian radiation hydrodynamics direct drive simulations. Additionally, simulations provide strong incentive to further modify key parameters within the SNB theory, namely the ``mean free path.'' An example 2D polar drive simulation to study 2D effects of the nonlocal flux as well as mean free path modifications will also be presented. This research was supported by the University of Rochester Laboratory for Laser Energetics.

A multimodal assessment of driving performance in HIV infection.

PubMed

Marcotte, T D; Wolfson, T; Rosenthal, T J; Heaton, R K; Gonzalez, R; Ellis, R J; Grant, I

2004-10-26

To examine if HIV-seropositive (HIV+) individuals are at risk for impaired driving. Sixty licensed drivers (40 HIV+, 20 HIV-) completed a neuropsychological (NP) test battery and driving assessments. Eleven HIV+ subjects were NP-impaired. Driving-related skills were assessed using 1) two driving simulations (examining accident avoidance and navigational abilities), 2) the Useful Field of View (UFOV) test, and 3) an on-road evaluation. HIV+ NP-impaired subjects had greater difficulty than cognitively intact subjects on all driving measures, whereas the HIV- and HIV+ NP-normal groups performed similarly. On the UFOV, the HIV+ NP-impaired group had worse performance on Visual Processing and Divided Attention tasks but not in overall risk classification. They also had a higher number of simulator accidents (1.3 vs 2.0; p = 0.03), were less efficient at completing the navigation task (3.2 vs 9.2 blocks; p = 0.001), and were more likely to fail the on-road evaluation (6 vs 36%; p = 0.02). Impairment in Executive Functioning was the strongest NP predictor of failing the on-road drive test. NP performance and both simulations independently contributed to a model predicting 48% of the variance in on-road performance. HIV+ NP-impaired individuals are at increased risk for on-road driving impairments, whereas HIV+ individuals with normal cognition are not at a significantly higher risk than HIV- subjects. Executive Functioning is most strongly associated with impaired on-road performance. Cognitive and simulator testing may each provide data in identifying driving-impaired individuals.

Investigating driving behaviour of older drivers with mild cognitive impairment using a portable driving simulator.

PubMed

Devlin, Anna; McGillivray, Jane; Charlton, Judith; Lowndes, Georgia; Etienne, Virginie

2012-11-01

While there is a large body of research indicating that individuals with moderate to severe dementia are unfit to drive, relatively little is known about the driving performance of older drivers with mild cognitive impairment (MCI). The aim of the current study was to examine the driving performance of older drivers with MCI on approach to intersections, and to investigate how their healthy counterparts perform on the same driving tasks using a portable driving simulator. Fourteen drivers with MCI and 14 age-matched healthy older drivers (aged 65-87 years) completed a 10-min simulator drive in an urban environment. The simulator drive consisted of stop-sign controlled and signal-controlled intersections. Drivers were required to stop at the stop-sign controlled intersections and to decide whether or not to proceed through a critical light change at the signal-controlled intersections. The specific performance measures included; approach speed, number of brake applications on approach to the intersection (either excessive or minimal), failure to comply with stop signs, and slower braking response times on approach to a critical light change. MCI patients in our sample performed more poorly than controls across a number of variables. However, because the trends failed to reach statistical significance it will be important to replicate the study using a larger sample to qualify whether the results can be generalised to the broader population. Copyright © 2012 Elsevier Ltd. All rights reserved.

Rifaximin Improves Driving Simulator Performance in a Randomized Trial of Patients with Minimal Hepatic Encephalopathy

PubMed Central

Bajaj, Jasmohan S; Heuman, Douglas M; Wade, James B; Gibson, Douglas P; Saeian, Kia; Wegelin, Jacob A; Hafeezullah, Muhammad; Bell, Debulon E; Sterling, Richard K; Stravitz, R. Todd; Fuchs, Michael; Luketic, Velimir; Sanyal, Arun J

2010-01-01

Background & Aims Patients with cirrhosis and minimal hepatic encephalopathy (MHE) have driving difficulties but the effects of therapy on driving performance have not been assessed. We evaluated whether performance on a driving simulator improves in patients with MHE following treatment with rifaximin. Methods Patients with MHE who were current drivers were randomly assigned to placebo or rifaximin groups and followed for 8 weeks (n=42). Patients underwent driving simulation (driving and navigation tasks) at the start (baseline) and end of the study. We evaluated patients’ cognitive abilities, quality-of-life (using the Sickness Impact Profile [SIP]), serum levels of ammonia, levels of inflammatory cytokines, and MELD scores. The primary outcome was percent who improved in driving performance, calculated by: total driving errors=speeding + illegal turns + collisions. Results Over the 8-week study period, patients given rifaximin made significantly greater improvements than those given placebo in avoiding total driving errors (76% vs. 31%, P=0.013), speeding (81% vs. 33%, P=0.005), and illegal turns (62% vs. 19%, P=0.01). Of patients given rifaximin, 91% improved their cognitive performance, compared with 61% of patients given placebo (P=0.01); they also made improvements in the psycho-social dimension of the SIP, compared with the placebo group (P=0.04). Adherence to the assigned drug averaged 92%. Neither group had changes in ammonia levels or MELD scores, but patients in the rifaximin group had increased levels of the anti-inflammatory cytokine interleukin-10. Conclusions Patients with MHE significantly improve driving simulator performance following treatment with rifaximin, compared with placebo. PMID:20849805

Can Youth with Autism Spectrum Disorder Use Virtual Reality Driving Simulation Training to Evaluate and Improve Driving Performance? An Exploratory Study.

PubMed

Cox, Daniel J; Brown, Timothy; Ross, Veerle; Moncrief, Matthew; Schmitt, Rose; Gaffney, Gary; Reeve, Ron

2017-08-01

Investigate how novice drivers with autism spectrum disorder (ASD) differ from experienced drivers and whether virtual reality driving simulation training (VRDST) improves ASD driving performance. 51 novice ASD drivers (mean age 17.96 years, 78% male) were randomized to routine training (RT) or one of three types of VRDST (8-12 sessions). All participants followed DMV behind-the-wheel training guidelines for earning a driver's license. Participants were assessed pre- and post-training for driving-specific executive function (EF) abilities and tactical driving skills. ASD drivers showed worse baseline EF and driving skills than experienced drivers. At post-assessment, VRDST significantly improved driving and EF performance over RT. This study demonstrated feasibility and potential efficacy of VRDST for novice ASD drivers.

HERA Broadband Feed Design for Low-Frequency Radio Astronomy

NASA Astrophysics Data System (ADS)

Garza, Sierra; Trung, Vincent; Ewall-Wice, Aaron Michael; Li, Jianshu; Hewitt, Jacqueline; Riley, Daniel; Bradley, Richard F.; Makhija, Krishna

2018-01-01

As part of the Hydrogen Epoch of Reionization Array (HERA) project, we are designing a broadband low-frequency radio feed to extend the bandwidth from 100-200 MHz to 50-220 MHz. By extending the lower-limit to 50 MHz, we hope to detect the signatures of the first black holes heating the hydrogen gas in the intergalactic medium.The isolation of a very faint signal from vastly brighter foregrounds sets strict requirements on antenna spectral smoothness, polarization purity, forward gain, and internal reflections. We are currently working to meet these requirements with a broad-band sinuous antenna feed suspended over the 14-m parabolic HERA dish, using a combination of measurements and simulations to verify the performance of our design.A sinuous feed has been designed and simulated with Computer Simulation Technology (CST) software. We will present the construction of a prototype sinuous antenna and measurements of its reflection coefficient, S11, including laboratory characterization of baluns. Our measurements agree well with the CST simulations of the antenna’s performance, giving us confidence in our ability to model the feed and ensure that it meets the requirements of a 21cm cosmology measurement.

Effects of prolonged wakefulness combined with alcohol and hands-free cell phone divided attention tasks on simulated driving.

PubMed

Iudice, A; Bonanni, E; Gelli, A; Frittelli, C; Iudice, G; Cignoni, F; Ghicopulos, I; Murri, L

2005-03-01

Simulated driving ability was assessed following administration of alcohol, at an estimated blood level of 0.05%, and combined prolonged wakefulness, while participants were undertaking divided attention tasks over a hands-free mobile phone. Divided attention tasks were structured to provide a sustained cognitive workload to the subjects. Twenty three young healthy individuals drove 10 km simulated driving under four conditions in a counterbalanced, within-subject design: alcohol, alcohol and 19 h wakefulness, alcohol and 24 h wakefulness, and while sober. Study measures were: simulated driving, self-reported sleepiness, critical flicker fusion threshold (CFFT), Stroop word-colour interference test (Stroop) and simple visual reaction times (SVRT). As expected, subjective sleepiness was highly correlated with both sleep restriction and alcohol consumption. The combination of alcohol and 24 h sustained wakefulness produced the highest driving impairment, significantly beyond the alcohol effect itself. Concurrent alcohol and 19 h wakefulness significantly affected only driving time-to-collision. No significant changes of study measures occurred following alcohol intake in unrestricted sleep conditions. CFFT, SVRT and Stroop results showed a similar trend in the four study conditions. Thus apparently 'safe' blood alcohol levels in combination with prolonged wakefulness resulted in significant driving impairments. In normal sleep conditions alcohol effects on driving were partially counteracted by the concomitant hands-free phone based psychometric tasks. 2005 John Wiley & Sons, Ltd.

Driving comfort, enjoyment and acceptance of automated driving - effects of drivers' age and driving style familiarity.

PubMed

Hartwich, Franziska; Beggiato, Matthias; Krems, Josef F

2018-02-23

Automated driving has the potential to improve the safety and efficiency of future traffic and to extend elderly peoples' driving life, provided it is perceived as comfortable and joyful and is accepted by drivers. Driving comfort could be enhanced by familiar automated driving styles based on drivers' manual driving styles. In a two-stage driving simulator study, effects of driving automation and driving style familiarity on driving comfort, enjoyment and system acceptance were examined. Twenty younger and 20 older drivers performed a manual and four automated drives of different driving style familiarity. Acceptance, comfort and enjoyment were assessed after driving with standardised questionnaires, discomfort during driving via handset control. Automation increased both age groups' comfort, but decreased younger drivers' enjoyment. Younger drivers showed higher comfort, enjoyment and acceptance with familiar automated driving styles, whereas older drivers preferred unfamiliar, automated driving styles tending to be faster than their age-affected manual driving styles. Practitioner Summary: Automated driving needs to be comfortable and enjoyable to be accepted by drivers, which could be enhanced by driving style individualisation. This approach was evaluated in a two-stage driving simulator study for different age groups. Younger drivers preferred familiar driving styles, whereas older drivers preferred driving styles unaffected by age.

AGN feedback compared: jets versus radiation

NASA Astrophysics Data System (ADS)

Cielo, Salvatore; Bieri, Rebekka; Volonteri, Marta; Wagner, Alexander Y.; Dubois, Yohan

2018-06-01

Feedback by active galactic nuclei (AGNs) is often divided into quasar and radio mode, powered by radiation or radio jets, respectively. Both are fundamental in galaxy evolution, especially in late-type galaxies, as shown by cosmological simulations and observations of jet-ISM (interstellar medium) interactions in these systems. We compare AGN feedback by radiation and by collimated jets through a suite of simulations, in which a central AGN interacts with a clumpy, fractal galactic disc. We test AGNs of 1043 and 1046 erg s-1, considering jets perpendicular or parallel to the disc. Mechanical jets drive the more powerful outflows, exhibiting stronger mass and momentum coupling with the dense gas, while radiation heats and rarefies the gas more. Radiation and perpendicular jets evolve to be quite similar in outflow properties and effect on the cold ISM, while inclined jets interact more efficiently with all the disc gas, removing the densest 20 {per cent} in 20 Myr, and thereby reducing the amount of cold gas available for star formation. All simulations show small-scale inflows of 0.01-0.1 M⊙ yr-1, which can easily reach down to the Bondi radius of the central supermassive black hole (especially for radiation and perpendicular jets), implying that AGNs modulate their own duty cycle in a feedback/feeding cycle.

High Fidelity System Simulation of Multiple Components in Support of the UEET Program

NASA Technical Reports Server (NTRS)

Plybon, Ronald C.; VanDeWall, Allan; Sampath, Rajiv; Balasubramaniam, Mahadevan; Mallina, Ramakrishna; Irani, Rohinton

2006-01-01

The High Fidelity System Simulation effort has addressed various important objectives to enable additional capability within the NPSS framework. The scope emphasized High Pressure Turbine and High Pressure Compressor components. Initial effort was directed at developing and validating intermediate fidelity NPSS model using PD geometry and extended to high-fidelity NPSS model by overlaying detailed geometry to validate CFD against rig data. Both "feedforward" and feedback" approaches of analysis zooming was employed to enable system simulation capability in NPSS. These approaches have certain benefits and applicability in terms of specific applications "feedback" zooming allows the flow-up of information from high-fidelity analysis to be used to update the NPSS model results by forcing the NPSS solver to converge to high-fidelity analysis predictions. This apporach is effective in improving the accuracy of the NPSS model; however, it can only be used in circumstances where there is a clear physics-based strategy to flow up the high-fidelity analysis results to update the NPSS system model. "Feed-forward" zooming approach is more broadly useful in terms of enabling detailed analysis at early stages of design for a specified set of critical operating points and using these analysis results to drive design decisions early in the development process.

Predicting drowsy driving in real-time situations: Using an advanced driving simulator, accelerated failure time model, and virtual location-based services.

PubMed

Wang, Junhua; Sun, Shuaiyi; Fang, Shouen; Fu, Ting; Stipancic, Joshua

2017-02-01

This paper aims to both identify the factors affecting driver drowsiness and to develop a real-time drowsy driving probability model based on virtual Location-Based Services (LBS) data obtained using a driving simulator. A driving simulation experiment was designed and conducted using 32 participant drivers. Collected data included the continuous driving time before detection of drowsiness and virtual LBS data related to temperature, time of day, lane width, average travel speed, driving time in heavy traffic, and driving time on different roadway types. Demographic information, such as nap habit, age, gender, and driving experience was also collected through questionnaires distributed to the participants. An Accelerated Failure Time (AFT) model was developed to estimate the driving time before detection of drowsiness. The results of the AFT model showed driving time before drowsiness was longer during the day than at night, and was longer at lower temperatures. Additionally, drivers who identified as having a nap habit were more vulnerable to drowsiness. Generally, higher average travel speeds were correlated to a higher risk of drowsy driving, as were longer periods of low-speed driving in traffic jam conditions. Considering different road types, drivers felt drowsy more quickly on freeways compared to other facilities. The proposed model provides a better understanding of how driver drowsiness is influenced by different environmental and demographic factors. The model can be used to provide real-time data for the LBS-based drowsy driving warning system, improving past methods based only on a fixed driving. Copyright © 2016 Elsevier Ltd. All rights reserved.

High on food: the interaction between the neural circuits for feeding and for reward.

PubMed

Liu, Jing-Jing; Mukherjee, Diptendu; Haritan, Doron; Ignatowska-Jankowska, Bogna; Liu, Ji; Citri, Ami; Pang, Zhiping P

2015-04-01

Hunger, mostly initiated by a deficiency in energy, induces food seeking and intake. However, the drive toward food is not only regulated by physiological needs, but is motivated by the pleasure derived from ingestion of food, in particular palatable foods. Therefore, feeding is viewed as an adaptive motivated behavior that involves integrated communication between homeostatic feeding circuits and reward circuits. The initiation and termination of a feeding episode are instructed by a variety of neuronal signals, and maladaptive plasticity in almost any component of the network may lead to the development of pathological eating disorders. In this review we will summarize the latest understanding of how the feeding circuits and reward circuits in the brain interact. We will emphasize communication between the hypothalamus and the mesolimbic dopamine system and highlight complexities, discrepancies, open questions and future directions for the field.

The effect of feedback on attitudes toward cellular phone use while driving: a comparison between novice and experienced drivers.

PubMed

Wang, Ying; Zhang, Wei; Reimer, Bryan; Lavallière, Martin; Lesch, Mary F; Horrey, William J; Wu, Su

2010-10-01

To assess and compare the effectiveness of a simulation-based approach to change drivers' attitudes toward cellular phone use while driving for younger novice and older experienced drivers. Thirty young novice drivers were tested on a driving simulator in this study. Their performance in dealing with driving tasks was measured for a single task and dual tasks (driving while using a cellular phone) and compared to 30 older experienced drivers tested previously in another study. Half of the younger drivers received video-based feedback regarding their performance in the two conditions, with an emphasis on the contribution of dual-tasking to degraded performance. The other half did not receive any performance feedback. Drivers' perceptions and attitudes toward cellular phone use while driving were investigated by a questionnaire before, immediately after, and again one month following the simulation-based testing for both groups of drivers (feedback; no feedback). All drivers (including the novice and experienced) reported willingness to engage in driving and talking on a cellular phone in some situations. The simulated driving test showed that a secondary cellular phone task significantly degraded driving performance for both the novice and the experienced drivers. The feedback treatment group (both the novice and the experienced) showed significant attitude change toward cellular phone use while driving (toward being less favorable), whereas the control group had no attitude change. At the one-month follow-up, the benefit of feedback was sustained more so in the experienced driver group than the novice driver group, although both groups still benefited relative to the control conditions. Simulation-based feedback training is promising for short-term education in novice drivers but may be more effective in the long-term for drivers with higher levels of experience. Drivers with more experience appear to have a greater, more sustained benefit from the training than novices. Additional research is needed to better tailor this education method toward novice drivers. Simulation-based participative education approach through feedback needs to be better tailored toward novice drivers.

Promotion and Prevention Focused Feeding Strategies: Exploring the Effects on Healthy and Unhealthy Child Eating.

PubMed

Melbye, Elisabeth L; Hansen, Håvard

2015-01-01

There is a general lack of research addressing the motivations behind parental use of various feeding practices. Therefore, the present work aims to extend the current literature on parent-child feeding interactions by integrating the traditional developmental psychological perspective on feeding practices with elements of Regulatory Focus Theory (RFT) derived from the field of motivational psychology. In this paper, we seek to explain associations between parental feeding practices and child (un)healthy eating behaviors by categorizing parental feeding practices into promotion and prevention focused strategies, thus exploring parent-child feeding interactions within the framework of RFT. Our analyses partly supported the idea that (1) child healthy eating is positively associated with feeding practices characterized as promotion focused, and (2) child unhealthy eating is negatively associated with feeding practices characterized as prevention focused. However, a general observation following from our results suggests that parents' major driving forces behind reducing children's consumption of unhealthy food items and increasing their consumption of healthy food items are strategies that motivate rather than restrict. In particular, parents' provision of a healthy home food environment seems to be essential for child eating.

Promotion and Prevention Focused Feeding Strategies: Exploring the Effects on Healthy and Unhealthy Child Eating

PubMed Central

Melbye, Elisabeth L.; Hansen, Håvard

2015-01-01

There is a general lack of research addressing the motivations behind parental use of various feeding practices. Therefore, the present work aims to extend the current literature on parent-child feeding interactions by integrating the traditional developmental psychological perspective on feeding practices with elements of Regulatory Focus Theory (RFT) derived from the field of motivational psychology. In this paper, we seek to explain associations between parental feeding practices and child (un)healthy eating behaviors by categorizing parental feeding practices into promotion and prevention focused strategies, thus exploring parent-child feeding interactions within the framework of RFT. Our analyses partly supported the idea that (1) child healthy eating is positively associated with feeding practices characterized as promotion focused, and (2) child unhealthy eating is negatively associated with feeding practices characterized as prevention focused. However, a general observation following from our results suggests that parents' major driving forces behind reducing children's consumption of unhealthy food items and increasing their consumption of healthy food items are strategies that motivate rather than restrict. In particular, parents' provision of a healthy home food environment seems to be essential for child eating. PMID:26380269

The Impact of Distraction on the Driving Performance of Adolescents with and without Attention Deficit Hyperactivity Disorder

PubMed Central

Narad, Megan; Garner, Annie A.; Brassell, Anne A.; Saxby, Dyani; Antonini, Tanya N.; O'Brien, Kathleen M.; Tamm, Leanne; Matthews, Gerald; Epstein, Jeffery N.

2013-01-01

Importance This study extends the literature regarding Attention-Deficit/Hyperactivity Disorder (ADHD) related driving impairments to a newly-licensed, adolescent population. Objective To investigate the combined risks of adolescence, ADHD, and distracted driving (cell phone conversation and text messaging) on driving performance. Design Adolescents with and without ADHD engaged in a simulated drive under three conditions (no distraction, cell phone conversation, texting). During each condition, one unexpected event (e.g., car suddenly merging into driver's lane) was introduced. Setting Driving simulator. Participants Adolescents aged 16–17 with ADHD (n=28) and controls (n=33). Interventions/Main Exposures Cell phone conversation, texting, and no distraction while driving. Outcome Measures Self-report of driving history; Average speed, standard deviation of speed, standard deviation of lateral position, braking reaction time during driving simulation. Results Adolescents with ADHD reported fewer months of driving experience and a higher proportion of driving violations than controls. After controlling for months of driving history, adolescents with ADHD demonstrated more variability in speed and lane position than controls. There were no group differences for braking reaction time. Further, texting negatively impacted the driving performance of all participants as evidenced by increased variability in speed and lane position. Conclusions This study, one of the first to investigate distracted driving in adolescents with ADHD, adds to a growing body of literature documenting that individuals with ADHD are at increased risk for negative driving outcomes. Furthermore, texting significantly impairs the driving performance of all adolescents and increases existing driving-related impairment in adolescents with ADHD, highlighting the need for education and enforcement of regulations against texting for this age group. PMID:23939758

Association between unsafe driving performance and cognitive-perceptual dysfunction in older drivers.

PubMed

Park, Si-Woon; Choi, Eun Seok; Lim, Mun Hee; Kim, Eun Joo; Hwang, Sung Il; Choi, Kyung-In; Yoo, Hyun-Chul; Lee, Kuem Ju; Jung, Hi-Eun

2011-03-01

To find an association between cognitive-perceptual problems of older drivers and unsafe driving performance during simulated automobile driving in a virtual environment. Cross-sectional study. A driver evaluation clinic in a rehabilitation hospital. Fifty-five drivers aged 65 years or older and 48 drivers in their late twenties to early forties. All participants underwent evaluation of cognitive-perceptual function and driving performance, and the results were compared between older and younger drivers. The association between cognitive-perceptual function and driving performance was analyzed. Cognitive-perceptual function was evaluated with the Cognitive Perceptual Assessment for Driving (CPAD), a computer-based assessment tool consisting of depth perception, sustained attention, divided attention, the Stroop test, the digit span test, field dependency, and trail-making test A and B. Driving performance was evaluated with use of a virtual reality-based driving simulator. During simulated driving, car crashes were recorded, and an occupational therapist observed unsafe performances in controlling speed, braking, steering, vehicle positioning, making lane changes, and making turns. Thirty-five older drivers did not pass the CPAD test, whereas all of the younger drivers passed the test. When using the driving simulator, a significantly greater number of older drivers experienced car crashes and demonstrated unsafe performance in controlling speed, steering, and making lane changes. CPAD results were associated with car crashes, steering, vehicle positioning, and making lane changes. Older drivers who did not pass the CPAD test are 4 times more likely to experience a car crash, 3.5 times more likely to make errors in steering, 2.8 times more likely to make errors in vehicle positioning, and 6.5 times more likely to make errors in lane changes than are drivers who passed the CPAD test. Unsafe driving performance and car crashes during simulated driving were more prevalent in older drivers than in younger drivers. Unsafe performance in steering, vehicle positioning, making lane changes, and car crashes were associated with cognitive-perceptual dysfunction. Copyright © 2011 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Cambrian cinctan echinoderms shed light on feeding in the ancestral deuterostome

PubMed Central

Rahman, Imran A.; Zamora, Samuel; Falkingham, Peter L.; Phillips, Jeremy C.

2015-01-01

Reconstructing the feeding mode of the latest common ancestor of deuterostomes is key to elucidating the early evolution of feeding in chordates and allied phyla; however, it is debated whether the ancestral deuterostome was a tentaculate feeder or a pharyngeal filter feeder. To address this, we evaluated the hydrodynamics of feeding in a group of fossil stem-group echinoderms (cinctans) using computational fluid dynamics. We simulated water flow past three-dimensional digital models of a Cambrian fossil cinctan in a range of possible life positions, adopting both passive tentacular feeding and active pharyngeal filter feeding. The results demonstrate that an orientation with the mouth facing downstream of the current was optimal for drag and lift reduction. Moreover, they show that there was almost no flow to the mouth and associated marginal groove under simulations of passive feeding, whereas considerable flow towards the animal was observed for active feeding, which would have enhanced the transport of suspended particles to the mouth. This strongly suggests that cinctans were active pharyngeal filter feeders, like modern enteropneust hemichordates and urochordates, indicating that the ancestral deuterostome employed a similar feeding strategy. PMID:26511049

FINAL REPORT DM1200 TESTS WITH AZ 101 HLW SIMULANTS VSL-03R3800-4 REV 0 2/17/04

DOE Office of Scientific and Technical Information (OSTI.GOV)

KRUGER AA; MATLACK KS; BARDAKCI T

2011-12-29

This report documents melter and off-gas performance results obtained on the DM 1200 HLW Pilot Melter during processing of simulated HLW AZ-101 feed. The principal objectives of the DM1200 melter testing were to determine the achievable glass production rates for simulated HLW AZ-101 feed; determine the effect of bubbling rate and feed solids content on production rate; characterize melter off-gas emissions; characterize the performance of the prototypical off-gas system components as well as their integrated performance; characterize the feed, glass product, and off-gas effluents; and to perform pre- and post-test inspections of system components. The test objectives (including test successmore » criteria), along with how they were met, are outlined in a table.« less

Drosophila Neuropeptide F Signaling Independently Regulates Feeding and Sleep-Wake Behavior.

PubMed

Chung, Brian Y; Ro, Jennifer; Hutter, Sabine A; Miller, Kylie M; Guduguntla, Lakshmi S; Kondo, Shu; Pletcher, Scott D

2017-06-20

Proper regulation of sleep-wake behavior and feeding is essential for organismal health and survival. While previous studies have isolated discrete neural loci and substrates important for either sleep or feeding, how the brain is organized to coordinate both processes with respect to one another remains poorly understood. Here, we provide evidence that the Drosophila Neuropeptide F (NPF) network forms a critical component of both adult sleep and feeding regulation. Activation of NPF signaling in the brain promotes wakefulness and adult feeding, likely through its cognate receptor NPFR. Flies carrying a loss-of-function NPF allele do not suppress sleep following prolonged starvation conditions, suggesting that NPF acts as a hunger signal to keep the animal awake. NPF-expressing cells, specifically those expressing the circadian photoreceptor cryptochrome, are largely responsible for changes to sleep behavior caused by NPF neuron activation, but not feeding, demonstrating that different NPF neurons separately drive wakefulness and hunger. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Nutrition and muscle catabolism in maintenance hemodialysis: does feeding make muscle cells selective self-eaters?

PubMed

Franch, Harold A

2009-01-01

Efforts to build muscle by increased protein feeding in hemodialysis patients have been thwarted by parallel increases in both muscle protein synthesis and degradation. The evidence suggests that muscle cells replace older proteins in response to feeding rather than using new proteins to drive muscle cell hypertrophy. This review presents the hypothesis that protein feeding provides an opportunity for muscle to accelerate proteolysis of proteins that have been damaged by oxidation, nitrosylation, and/or glycosylation and to replace damaged mitochondria that contribute to oxidative stress. Increases in proteolysis with feeding are driven by insulin resistance and the increased oxidative stress of mitochondrial respiration. Oxidized proteins and organelles are excellent substrates for degradation by the proteasome, macroautophagy, and chaperone-mediated autophagy: these systems of proteolysis seem to be activated by oxydatiative stress. Replacement of oxidized and other damaged proteins may be a benefit of protein feeding in hemodialysis, but alternative strategies, including exercise, will be required to build muscle.

Nutrition and Muscle Catabolism in Maintenance Hemodialysis: Does Feeding Make Muscle Cells Selective Self-Eaters?

PubMed Central

Franch, Harold A.

2009-01-01

Efforts to build muscle by increased protein feeding in hemodialysis patients have been thwarted by parallel increases in both muscle protein synthesis and degradation. The evidence suggests that muscle cells replace older proteins in response to feeding rather than using new proteins to drive muscle cell hypertrophy. This review presents the hypothesis that protein feeding provides an opportunity for muscle to accelerate proteolysis of proteins which have been damaged by oxidation, nitrosylation and/or glycosylation and to replace damaged mitochondria that contribute to oxidative stress. Increases in proteolysis with feeding are driven by insulin resistance and the increased oxidative stress of mitochondrial respiration. Oxidized proteins and organelles are excellent substrates for degradation by the proteasome, macroautophagy, and chaperone-mediated autophagy: these systems of proteolysis seem to be activated by oxydatiative stress. Replacement of oxidized and other damaged proteins may be a benefit of protein feeding in hemodialysis, but alternative strategies, including exercise, will be required to build muscle. PMID:19121779

The development and clinical trial of a Driving Simulator for the handicapped.

PubMed

Ku, Jeonghun; Jang, Dongpyo; Ahn, Heebum; Lee, Jaemin; Kim, Jeong A; Lee, Bumseok; Kim, In Y; Kim, Sun I

2002-01-01

We developed a Virtual Reality Driving Simulator in order to safely evaluate and improve the driving ability of the handicapped. The Virtual Environment consists of 18 sections (e.g. a speed limited road, a strait road, a curved road, a left turn course, etc) and each section is linked naturally. For the interface of our driving simulator, an actual car was adapted for realism and then connected to a computer. We also equipped it with hand control driving devices especially adapted for the handicapped. A beam projector was used so that the subjects could see the virtual scene on a large screen which was set in front of them. The subjects selected for this trial were 10 normal drivers with valid driving licenses and 15 patients with thoracicor lumber cord injuries who had prior driving experience. For evaluation, 5 driving skills were measured including average speed, steering stability, centerline violations, traffic signal violations, and driving time in various road conditions such as strait and curved roads. The normal subjects manipulated the gas pedal and the brake with their feet while the patients manipulated a hand control with their hands. After they finished driving the whole course, the participants answered the questions such as "How realistic did the Virtual Reality Driving Simulator seeme to you?" and "How much was your fear reduced". The five driving skills measured between the two groups (normal vs. handicapped) did not show any significant differences (p > 0.05). And in the three kinds of road conditions (a speed limited road and roads with a sharp curve and left-hand turn), the average speed of the handicapped group was 45.6 Km, less than 61.2 Km (p<0.05) of the normal group. In all, 11 patients (73%) reported that their fear of driving was reduced. Furthermore, their average score on the degree of realism question was 51.5%.

Crash avoidance in response to challenging driving events: The roles of age, serialization, and driving simulator platform.

PubMed

Bélanger, Alexandre; Gagnon, Sylvain; Stinchcombe, Arne

2015-09-01

We examined the crash avoidance behaviors of older and middle-aged drivers in reaction to six simulated challenging road events using two different driving simulator platforms. Thirty-five healthy adults aged 21-36 years old (M=28.9±3.96) and 35 healthy adults aged 65-83 years old (M=72.1±4.34) were tested using a mid-level simulator, and 27 adults aged 21-38 years old (M=28.6±6.63) and 27 healthy adults aged 65-83 years old (M=72.7±5.39) were tested on a low-cost desktop simulator. Participants completed a set of six challenging events varying in terms of the maneuvers required, avoiding space given, directional avoidance cues, and time pressure. Results indicated that older drivers showed higher crash risk when events required multiple synchronized reactions. In situations that required simultaneous use of steering and braking, older adults tended to crash significantly more frequently. As for middle-aged drivers, their crashes were attributable to faster driving speed. The same age-related driving patterns were observed across simulator platforms. Our findings support the hypothesis that older adults tend to react serially while engaging in cognitively challenging road maneuvers. Copyright © 2015 Elsevier Ltd. All rights reserved.

Simulator training with a forward collision warning system: effects on driver-system interactions and driver trust.

PubMed

Koustanaï, Arnaud; Cavallo, Viola; Delhomme, Patricia; Mas, Arnaud

2012-10-01

The study addressed the role of familiarization on a driving simulator with a forward collision warning (FCW) and investigated its impact on driver behavior. Drivers need a good understanding of how an FCW system functions to trust it and use it properly. Theoretical and empirical data suggest that exploring the capacities and limitations of the FCW during the learning period improves operating knowledge and leads to increased driver trust in the system and better driver-system interactions.The authors tested this hypothesis by comparing groups of drivers differing in FCW familiarity. During the familiarization phase, familiarized drivers were trained on the simulator using the FCW, unfamiliarized drivers simply read an FCW manual, and control drivers had no contact with the FCW. During the test, drivers drove the simulator and had to interact with traffic; both familiarized and unfamiliarized drivers used the FCW, whereas controls did not. Simulator familiarization improved driver understanding of FCW operation. Driver-system interactions were more effective: Familiarized drivers had no collisions, longer time headways, and better reactions in most situations. Familiarization increased trust in the FCW but did not raise system acceptance. Familiarization on the simulator had a positive effect on driver-system interactions and on trust in the system. The limitations of the familiarization method are discussed in relation to the driving simulator methodology. Practicing on a driving simulator with driving-assistance systems could facilitate their use during real driving.

Acetone-butanol-ethanol competitive sorption simulation from single, binary, and ternary systems in a fixed-bed of KA-I resin.

PubMed

Wu, Jinglan; Zhuang, Wei; Ying, Hanjie; Jiao, Pengfei; Li, Renjie; Wen, Qingshi; Wang, Lili; Zhou, Jingwei; Yang, Pengpeng

2015-01-01

Separation of butanol based on sorption methodology from acetone-butanol-ethanol (ABE) fermentation broth has advantages in terms of biocompatibility and stability, as well as economy, and therefore gains much attention. In this work a chromatographic column model based on the solid film linear driving force approach and the competitive Langmuir isotherm equations was used to predict the competitive sorption behaviors of ABE single, binary, and ternary mixture. It was observed that the outlet concentration of weaker retained components exceeded the inlet concentration, which is an evidence of competitive adsorption. Butanol, the strongest retained component, could replace ethanol almost completely and also most of acetone. In the end of this work, the proposed model was validated by comparison of the experimental and predicted ABE ternary breakthrough curves using the real ABE fermentation broth as a feed solution. © 2014 American Institute of Chemical Engineers.

Functional brain mapping of actual car-driving using [18F]FDG-PET.

PubMed

Jeong, Myeonggi; Tashiro, Manabu; Singh, Laxsmi N; Yamaguchi, Keiichiro; Horikawa, Etsuo; Miyake, Masayasu; Watanuki, Shouichi; Iwata, Ren; Fukuda, Hiroshi; Takahashi, Yasuo; Itoh, Masatoshi

2006-11-01

This study aims at identifying the brain activation during actual car-driving on the road, and at comparing the results to those of previous studies on simulated car-driving. Thirty normal volunteers, aged 20 to 56 years, were divided into three subgroups, active driving, passive driving and control groups, for examination by positron emission tomography (PET) and [18F]2-deoxy-2-fluoro-D-glucose (FDG). The active driving subjects (n = 10) drove for 30 minutes on quiet normal roads with a few traffic signals. The passive driving subjects (n = 10) participated as passengers on the front seat. The control subjects (n = 10) remained seated in a lit room with their eyes open. Voxel-based t-statistics were applied using SPM2 to search brain activation among the subgroups mentioned above. Significant brain activation was detected during active driving in the primary and secondary visual cortices, primary sensorimotor areas, premotor area, parietal association area, cingulate gyrus, the parahippocampal gyrus as well as in thalamus and cerebellum. The passive driving manifested a similar-looking activation pattern, lacking activations in the premotor area, cingulate and parahippocampal gyri and thalamus. Direct comparison of the active and passive driving conditions revealed activation in the cerebellum. The result of actual driving looked similar to that of simulated driving, suggesting that visual perception and visuomotor coordination were the main brain functions while driving. In terms of attention and autonomic arousal, however, it seems there was a significant difference between simulated and actual driving possibly due to risk of accidents. Autonomic and emotional aspects of driving should be studied using an actual driving study-design.

Simulation model for a seven-phase BLDCM drive system

NASA Astrophysics Data System (ADS)

Park, Sang-Hoon; Lee, Won-Cheol; Lee, Jung-Hyo; Yu, Jae-Sung; Kim, Gyu-Sik; Won, Chung-Yuen

2007-12-01

BLDC motors have many advantages over brushed DC motors and induction motors. So, BLDC motors extend their application to many industrial fields. In this paper, the digital simulation and modeling of a 7-phase brushless DC motor have been presented. The 14-switch inverter and a 7-phase brushless DC motor drive system are simulated using hysteresis current controller and logic of switching pattern with the Boolean¡s function. Through some simulations, we found that our modeling and analysis of a 7-phase BLDCM with PWM inverter would be helpful for the further studies of the multi-phase BLDCM drive systems.

The application of multilayer elastic beam in MEMS safe and arming system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Guozhong, E-mail: liguozhong-bit@bit.edu.cn; Shi, Gengchen; Sui, Li

In this paper, a new approach for a multilayer elastic beam to provide a driving force and driving distance for a MEMS safe and arming system is presented. In particular this is applied where a monolayer elastic beam cannot provide adequate driving force and driving distance at the same time in limited space. Compared with thicker elastic beams, the bilayer elastic beam can provide twice the driving force of a monolayer beam to guarantee the MEMS safe and arming systems work reliably without decreasing the driving distance. In this paper, the theoretical analysis, numerical simulation and experimental verification of themore » multilayer elastic beam is presented. The numerical simulation and experimental results show that the bilayer elastic provides 1.8–2 times the driving force of a monolayer, and a method that improves driving force without reducing the driving distance.« less

Design and simulation of the direct drive servo system

NASA Astrophysics Data System (ADS)

Ren, Changzhi; Liu, Zhao; Song, Libin; Yi, Qiang; Chen, Ken; Zhang, Zhenchao

2010-07-01

As direct drive technology is finding their way into telescope drive designs for its many advantages, it would push to more reliable and cheaper solutions for future telescope complex motion system. However, the telescope drive system based on the direct drive technology is one high integrated electromechanical system, which one complex electromechanical design method is adopted to improve the efficiency, reliability and quality of the system during the design and manufacture circle. The telescope is one ultra-exact, ultra-speed, high precision and huge inertial instrument, which the direct torque motor adopted by the telescope drive system is different from traditional motor. This paper explores the design process and some simulation results are discussed.

Investigating Simulated Driving Errors in Amnestic Single- and Multiple-Domain Mild Cognitive Impairment.

PubMed

Hird, Megan A; Vesely, Kristin A; Fischer, Corinne E; Graham, Simon J; Naglie, Gary; Schweizer, Tom A

2017-01-01

The areas of driving impairment characteristic of mild cognitive impairment (MCI) remain unclear. This study compared the simulated driving performance of 24 individuals with MCI, including amnestic single-domain (sd-MCI, n = 11) and amnestic multiple-domain MCI (md-MCI, n = 13), and 20 age-matched controls. Individuals with MCI committed over twice as many driving errors (20.0 versus 9.9), demonstrated difficulty with lane maintenance, and committed more errors during left turns with traffic compared to healthy controls. Specifically, individuals with md-MCI demonstrated greater driving difficulty compared to healthy controls, relative to those with sd-MCI. Differentiating between different subtypes of MCI may be important when evaluating driving safety.

Behavioral and Cardiovascular Responses to Frustration during Simulated Driving Tasks in Young Adults with and without Attention Disorder Symptoms

ERIC Educational Resources Information Center

Oliver, Michele L.; Nigg, Joel T.; Cassavaugh, Nicholas D.; Backs, Richard W.

2012-01-01

Objective: The present study examined the role of negative emotions on driving performance in relation to ADHD, by comparing young adults scoring high on measures of ADHD (n = 20) with a control group (n = 22). Method: The authors used cardiorespiratory physiological measures, simulated driving behavior, and self-report to examine how participants…

Phase stabilization for mode locked lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baer, M.T.

A method is described for stabilizing a phase relationship between two mode locked lasers, comprising: driving through a power splitter the mode lockers of both lasers from a single stable radio frequency source; monitoring the phase of pulses from each laser utilizing a fast photodiode output of each laser; feeding the output of the fast photodiodes to a phase detector and comparator; measuring a relative phase difference between the lasers with a phase detector and comparator, producing a voltage output signal or phase error signal representing the phase difference; amplifying and filtering the voltage output signal with an amplifier andmore » loop filter; feeding the resulting output signal to a voltage controlled phase delay between the power splitter and one of the lasers; and delaying the RF drive to the one laser to achieve a desired phase relationship, between the two lasers.« less

Effects of a malfunctional column on conventional and FeedCol-simulated moving bed chromatography performance.

PubMed

Song, Ji-Yeon; Oh, Donghoon; Lee, Chang-Ha

2015-07-17

The effects of a malfunctional column on the performance of a simulated moving bed (SMB) process were studied experimentally and theoretically. The experimental results of conventional four-zone SMB (2-2-2-2 configuration) and FeedCol operation (2-2-2-2 configuration with one feed column) with one malfunctional column were compared with simulation results of the corresponding SMB processes with a normal column configuration. The malfunctional column in SMB processes significantly deteriorated raffinate purity. However, the extract purity was equivalent or slightly improved compared with the corresponding normal SMB operation because the complete separation zone of the malfunctional column moved to a lower flow rate range in zones II and III. With the malfunctional column configuration, FeedCol operation gave better experimental performance (up to 7%) than conventional SMB operation because controlling product purity with FeedCol operation was more flexible through the use of two additional operating variables, injection time and injection length. Thus, compared with conventional SMB separation, extract with equivalent or slightly better purity could be produced from FeedCol operation even with a malfunctional column, while minimizing the decrease in raffinate purity (less than 2%). Copyright © 2015 Elsevier B.V. All rights reserved.

Cerebral oscillatory activity during simulated driving using MEG.

PubMed

Sakihara, Kotoe; Hirata, Masayuki; Ebe, Kazutoshi; Kimura, Kenji; Yi Ryu, Seong; Kono, Yoshiyuki; Muto, Nozomi; Yoshioka, Masako; Yoshimine, Toshiki; Yorifuji, Shiro

2014-01-01

We aimed to examine cerebral oscillatory differences associated with psychological processes during simulated car driving. We recorded neuromagnetic signals in 14 healthy volunteers using magnetoencephalography (MEG) during simulated driving. MEG data were analyzed using synthetic aperture magnetometry to detect the spatial distribution of cerebral oscillations. Group effects between subjects were analyzed statistically using a non-parametric permutation test. Oscillatory differences were calculated by comparison between "passive viewing" and "active driving." "Passive viewing" was the baseline, and oscillatory differences during "active driving" showed an increase or decrease in comparison with a baseline. Power increase in the theta band was detected in the superior frontal gyrus (SFG) during active driving. Power decreases in the alpha, beta, and low gamma bands were detected in the right inferior parietal lobe (IPL), left postcentral gyrus (PoCG), middle temporal gyrus (MTG), and posterior cingulate gyrus (PCiG) during active driving. Power increase in the theta band in the SFG may play a role in attention. Power decrease in the right IPL may reflect selectively divided attention and visuospatial processing, whereas that in the left PoCG reflects sensorimotor activation related to driving manipulation. Power decreases in the MTG and PCiG may be associated with object recognition.

Simulations of Flow Through the SSME LH2 Feed Line and LPFP Inducer

NASA Technical Reports Server (NTRS)

Dorney, Daniel J.; Rothermel, Jeffry

2003-01-01

During a post-flight inspection of the liquid hydrogen feed lines leading the Space Shuttle main engines cracks were discover in slots on a flow liner just upstream of the low pressure fuel pump inducer. Numerical simulations have been performed for the feed line, the flow liner (including the slots and backing cavity) and the inducer. The predicted results have been compared with experimental data taken during hot-fire tests at NASA Stennis Space Center.

An examination of the relationship between measures of impulsivity and risky simulated driving amongst young drivers.

PubMed

Hatfield, Julie; Williamson, Ann; Kehoe, E James; Prabhakharan, Prasannah

2017-06-01

The risky driving of young drivers may owe in part to youthful motivations (such as experience-seeking, authority rebellion, desire for peer approval) combined with incompletely developed impulse control. Although self-reported impulsiveness has been positively associated with self-reports of risky driving, results based on objective measures of response inhibition (e.g., Go/No-go tasks) have been inconclusive. The present study examined interrelationships between measures of response inhibition, self-report impulsiveness scales, and responses to events during a simulated drive that were designed to detect impulsive, unsafe behaviours (e.g., turning across on-coming traffic). Participants were 72 first-year Psychology students. More speeding and "Unsafe" responding to critical events during simulated driving were associated with poorer impulse control as assessed by commission errors during a Go/No-Go task. These results consolidate evidence for a relationship between impulse control and risky driving amongst young drivers. Copyright © 2017 Elsevier Ltd. All rights reserved.

Driving indicators in teens with attention deficit hyperactivity and/or autism spectrum disorder.

PubMed

Classen, Sherrilene; Monahan, Miriam; Brown, Kiah E; Hernandez, Stephanie

2013-12-01

Motor vehicle crashes are leading causes of death among teens. Those teens with attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), or a dual diagnosis of ADHD/ASD have defining characteristics placing them at a greater risk for crashes. This study examined the between-group demographic, clinical, and simulated driving differences in teens, representing three diagnostic groups, compared to healthy controls (HCs). In this prospective observational study, we used a convenience sample of teens recruited from a variety of community settings. Compared to the 22 HCs (mean age = 14.32, SD = +/-.72), teen drivers representing the diagnostic groups (ADHD/ASD, n = 6, mean age = 15.00, SD = +/-.63; ADHD, n = 9, mean age = 15.00, SD = +/- 1.00; ASD, n = 7, mean age = 15.14, SD = +/-. 1.22) performed poorer on visual function, visual-motor integration, cognition, and motor performance and made more errors on the driving simulator. Teens from diagnostic groups have more deficits driving on a driving simulator and may require a comprehensive driving evaluation.

Predicting Risk of Motor Vehicle Collisions in Patients with Glaucoma: A Longitudinal Study.

PubMed

Gracitelli, Carolina P B; Tatham, Andrew J; Boer, Erwin R; Abe, Ricardo Y; Diniz-Filho, Alberto; Rosen, Peter N; Medeiros, Felipe A

2015-01-01

To evaluate the ability of longitudinal Useful Field of View (UFOV) and simulated driving measurements to predict future occurrence of motor vehicle collision (MVC) in drivers with glaucoma. Prospective observational cohort study. 117 drivers with glaucoma followed for an average of 2.1 ± 0.5 years. All subjects had standard automated perimetry (SAP), UFOV, driving simulator, and cognitive assessment obtained at baseline and every 6 months during follow-up. The driving simulator evaluated reaction times to high and low contrast peripheral divided attention stimuli presented while negotiating a winding country road, with central driving task performance assessed as "curve coherence". Drivers with MVC during follow-up were identified from Department of Motor Vehicle records. Survival models were used to evaluate the ability of driving simulator and UFOV to predict MVC over time, adjusting for potential confounding factors. Mean age at baseline was 64.5 ± 12.6 years. 11 of 117 (9.4%) drivers had a MVC during follow-up. In the multivariable models, low contrast reaction time was significantly predictive of MVC, with a hazard ratio (HR) of 2.19 per 1 SD slower reaction time (95% CI, 1.30 to 3.69; P = 0.003). UFOV divided attention was also significantly predictive of MVC with a HR of 1.98 per 1 SD worse (95% CI, 1.10 to 3.57; P = 0.022). Global SAP visual field indices in the better or worse eye were not predictive of MVC. The longitudinal model including driving simulator performance was a better predictor of MVC compared to UFOV (R2 = 0.41 vs R2 = 0.18). Longitudinal divided attention metrics on the UFOV test and during simulated driving were significantly predictive of risk of MVC in glaucoma patients. These findings may help improve the understanding of factors associated with driving impairment related to glaucoma.

Design and simulation of MEMS-actuated adjustable optical wedge for laser beam scanners

NASA Astrophysics Data System (ADS)

Bahgat, Ahmed S.; Zaki, Ahmed H.; Abdo Mohamed, Mohamed; El Sherif, Ashraf Fathy

2018-01-01

This paper introduces both optical and mechanical design and simulation of large static deflection MOEMS actuator. The designed device is in the form of an adjustable optical wedge (AOW) laser scanner. The AOW is formed of 1.5-mm-diameter plano-convex lens separated by air gap from plano-concave fixed lens. The convex lens is actuated by staggered vertical comb drive and suspended by rectangular cross-section torsion beam. An optical analysis and simulation of air separated AOW as well as detailed design, analysis, and static simulation of comb -drive are introduced. The dynamic step response of the full system is also introduced. The analytical solution showed a good agreement with the simulation results. A general global minimum optimization algorithm is applied to the comb-drive design to minimize driving voltage. A maximum comb-drive mechanical deflection angle of 12 deg in each direction was obtained under DC actuation voltage of 32 V with a settling time of 90 ms, leading to 1-mm one-dimensional (1-D) steering of laser beam with continuous optical scan angle of 5 deg in each direction. This optimization process provided a design of larger deflection actuator with smaller driving voltage compared with other conventional devices. This enhancement could lead to better performance of MOEMS-based laser beam scanners for imaging and low-speed applications.

Design of an immersive simulator for assisted power wheelchair driving.

PubMed

Devigne, Louise; Babel, Marie; Nouviale, Florian; Narayanan, Vishnu K; Pasteau, Francois; Gallien, Philippe

2017-07-01

Driving a power wheelchair is a difficult and complex visual-cognitive task. As a result, some people with visual and/or cognitive disabilities cannot access the benefits of a power wheelchair because their impairments prevent them from driving safely. In order to improve their access to mobility, we have previously designed a semi-autonomous assistive wheelchair system which progressively corrects the trajectory as the user manually drives the wheelchair and smoothly avoids obstacles. Developing and testing such systems for wheelchair driving assistance requires a significant amount of material resources and clinician time. With Virtual Reality technology, prototypes can be developed and tested in a risk-free and highly flexible Virtual Environment before equipping and testing a physical prototype. Additionally, users can "virtually" test and train more easily during the development process. In this paper, we introduce a power wheelchair driving simulator allowing the user to navigate with a standard wheelchair in an immersive 3D Virtual Environment. The simulation framework is designed to be flexible so that we can use different control inputs. In order to validate the framework, we first performed tests on the simulator with able-bodied participants during which the user's Quality of Experience (QoE) was assessed through a set of questionnaires. Results show that the simulator is a promising tool for future works as it generates a good sense of presence and requires rather low cognitive effort from users.

Safety evaluation model of urban cross-river tunnel based on driving simulation.

PubMed

Ma, Yingqi; Lu, Linjun; Lu, Jian John

2017-09-01

Currently, Shanghai urban cross-river tunnels have three principal characteristics: increased traffic, a high accident rate and rapidly developing construction. Because of their complex geographic and hydrological characteristics, the alignment conditions in urban cross-river tunnels are more complicated than in highway tunnels, so a safety evaluation of urban cross-river tunnels is necessary to suggest follow-up construction and changes in operational management. A driving risk index (DRI) for urban cross-river tunnels was proposed in this study. An index system was also constructed, combining eight factors derived from the output of a driving simulator regarding three aspects of risk due to following, lateral accidents and driver workload. Analytic hierarchy process methods and expert marking and normalization processing were applied to construct a mathematical model for the DRI. The driving simulator was used to simulate 12 Shanghai urban cross-river tunnels and a relationship was obtained between the DRI for the tunnels and the corresponding accident rate (AR) via a regression analysis. The regression analysis results showed that the relationship between the DRI and the AR mapped to an exponential function with a high degree of fit. In the absence of detailed accident data, a safety evaluation model based on factors derived from a driving simulation can effectively assess the driving risk in urban cross-river tunnels constructed or in design.

Using exploratory regression to identify optimal driving factors for cellular automaton modeling of land use change.

PubMed

Feng, Yongjiu; Tong, Xiaohua

2017-09-22

Defining transition rules is an important issue in cellular automaton (CA)-based land use modeling because these models incorporate highly correlated driving factors. Multicollinearity among correlated driving factors may produce negative effects that must be eliminated from the modeling. Using exploratory regression under pre-defined criteria, we identified all possible combinations of factors from the candidate factors affecting land use change. Three combinations that incorporate five driving factors meeting pre-defined criteria were assessed. With the selected combinations of factors, three logistic regression-based CA models were built to simulate dynamic land use change in Shanghai, China, from 2000 to 2015. For comparative purposes, a CA model with all candidate factors was also applied to simulate the land use change. Simulations using three CA models with multicollinearity eliminated performed better (with accuracy improvements about 3.6%) than the model incorporating all candidate factors. Our results showed that not all candidate factors are necessary for accurate CA modeling and the simulations were not sensitive to changes in statistically non-significant driving factors. We conclude that exploratory regression is an effective method to search for the optimal combinations of driving factors, leading to better land use change models that are devoid of multicollinearity. We suggest identification of dominant factors and elimination of multicollinearity before building land change models, making it possible to simulate more realistic outcomes.

Metabolic and Demographic Feedbacks Shape the Emergent Spatial Structure and Function of Microbial Communities

PubMed Central

Estrela, Sylvie; Brown, Sam P.

2013-01-01

Microbes are predominantly found in surface-attached and spatially structured polymicrobial communities. Within these communities, microbial cells excrete a wide range of metabolites, setting the stage for interspecific metabolic interactions. The links, however, between metabolic and ecological interactions (functional relationships), and species spatial organization (structural relationships) are still poorly understood. Here, we use an individual-based modelling framework to simulate the growth of a two-species surface-attached community where food (resource) is traded for detoxification (service) and investigate how metabolic constraints of individual species shape the emergent structural and functional relationships of the community. We show that strong metabolic interdependence drives the emergence of mutualism, robust interspecific mixing, and increased community productivity. Specifically, we observed a striking and highly stable emergent lineage branching pattern, generating a persistent lineage mixing that was absent when the metabolic exchange was removed. These emergent community properties are driven by demographic feedbacks, such that aid from neighbouring cells directly enhances focal cell growth, which in turn feeds back to neighbour fecundity. In contrast, weak metabolic interdependence drives conflict (exploitation or competition), and in turn greater interspecific segregation. Together, these results support the idea that species structural and functional relationships represent the net balance of metabolic interdependencies. PMID:24385891

Impaired alertness and performance driving home from the night shift: a driving simulator study.

PubMed

Akerstedt, Torbjörn; Peters, Björn; Anund, Anna; Kecklund, Göran

2005-03-01

Driving in the early morning is associated with increased accident risk affecting not only professional drivers but also those who commute to work. The present study used a driving simulator to investigate the effects of driving home from a night shift. Ten shift workers participated after a normal night shift and after a normal night sleep. The results showed that driving home from the night shift was associated with an increased number of incidents (two wheels outside the lane marking, from 2.4 to 7.6 times), decreased time to first accident, increased lateral deviation (from 18 to 43 cm), increased eye closure duration (0.102 to 0.143 s), and increased subjective sleepiness. The results indicate severe postnight shift effects on sleepiness and driving performance.

High Impulse Gun Airborne Demonstration. GAU-13/A Weapon, Feed System, Gun Drive and Electronic Controls.

DTIC Science & Technology

1981-05-01

made to provide mounting bosses for the closed loop conveyor chute . Ten small round bosses were welded onto the housing to provide this support...became necessary to depart from previous closed loop feeder designs . The original feed system consisted of a series of conveyor elements in a flexible...The flexible chuting has been replaced with rigid chuting forming a loop around the gun housing. This design affords the maximum stiffness and hence

36. VIEW OF SOUTH END OF EAST BOILER ROOM LOOKING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

36. VIEW OF SOUTH END OF EAST BOILER ROOM LOOKING SOUTHWEST. THE CYLINDRICAL TANKS IN THE FOREGROUND CONTAIN AN ION-EXCHANGE RESIN FOR REMOVING CALCIUM FROM THE BOILER FEED TO REDUCE WATER "HARDNESS". THE SHALLOW TANK IN THE RIGHT BACKGROUND IS A DIATOMACEOUS EARTH FILTER TO REMOVE PARTICULATE MATTER FROM THE BOILER FEED. THE ION-EXCHANGE WATER SOFTENING SYSTEM WAS INSTALLED IN 1977. - New York, New Haven & Hartford Railroad, Cos Cob Power Plant, Sound Shore Drive, Greenwich, Fairfield County, CT

A teleonomic model describing performance (body, milk and intake) during growth and over repeated reproductive cycles throughout the lifespan of dairy cattle. 1. Trajectories of life function priorities and genetic scaling.

PubMed

Martin, O; Sauvant, D

2010-12-01

The prediction of the control of nutrient partitioning, particularly energy, is a major issue in modelling dairy cattle performance. The proportions of energy channelled to physiological functions (growth, maintenance, gestation and lactation) change as the animal ages and reproduces, and according to its genotype and nutritional environment. This is the first of two papers describing a teleonomic model of individual performance during growth and over repeated reproductive cycles throughout the lifespan of dairy cattle. The conceptual framework is based on the coupling of a regulating sub-model providing teleonomic drives to govern the work of an operating sub-model scaled with genetic parameters. The regulating sub-model describes the dynamic partitioning of a mammal female's priority between life functions targeted to growth (G), ageing (A), balance of body reserves (R) and nutrient supply of the unborn (U), newborn (N) and suckling (S) calf. The so-called GARUNS dynamic pattern defines a trajectory of relative priorities, goal directed towards the survival of the individual for the continuation of the specie. The operating sub-model describes changes in body weight (BW) and composition, foetal growth, milk yield and composition and food intake in dairy cows throughout their lifespan, that is, during growth, over successive reproductive cycles and through ageing. This dynamic pattern of performance defines a reference trajectory of a cow under normal husbandry conditions and feed regimen. Genetic parameters are incorporated in the model to scale individual performance and simulate differences within and between breeds. The model was calibrated for dairy cows with literature data. The model was evaluated by comparison with simulations of previously published empirical equations of BW, body condition score, milk yield and composition and feed intake. This evaluation showed that the model adequately simulates these production variables throughout the lifespan, and across a range of dairy cattle genotypes.

Rendering of dense, point cloud data in a high fidelity driving simulator.

DOT National Transportation Integrated Search

2014-09-01

Driving Simulators are advanced tools that can address many research questions in transportation. Recently they have been used to advance the practice of transportation engineering, specifically signs, signals, pavement markings, and most powerfully ...

Sliding Mode Control of Real-Time PNU Vehicle Driving Simulator and Its Performance Evaluation

NASA Astrophysics Data System (ADS)

Lee, Min Cheol; Park, Min Kyu; Yoo, Wan Suk; Son, Kwon; Han, Myung Chul

This paper introduces an economical and effective full-scale driving simulator for study of human sensibility and development of new vehicle parts and its control. Real-time robust control to accurately reappear a various vehicle motion may be a difficult task because the motion platform is the nonlinear complex system. This study proposes the sliding mode controller with a perturbation compensator using observer-based fuzzy adaptive network (FAN). This control algorithm is designed to solve the chattering problem of a sliding mode control and to select the adequate fuzzy parameters of the perturbation compensator. For evaluating the trajectory control performance of the proposed approach, a tracking control of the developed simulator named PNUVDS is experimentally carried out. And then, the driving performance of the simulator is evaluated by using human perception and sensibility of some drivers in various driving conditions.

COLLISION AVOIDANCE TRAINING USING A DRIVING SIMULATOR IN DRIVERS WITH PARKINSON’S DISEASE: A PILOT STUDY

PubMed Central

Dawson, Jeffrey D.; Rizzo, Matthew; Anderson, Steven W.; Dastrup, Elizabeth; Uc, Ergun Y.

2011-01-01

Summary Parkinson’s disease (PD) impairs driving performance, and simulator studies have shown increased crashes compared to controls. In this pilot study, eight drivers with PD participated in three drive sessions with multiple simulator intersections of varying visibility and traffic load, where an incurring vehicle posed a crash risk. Over the course of the three sessions (once every 1–2 weeks), we observed reduction in crashes (p=0.059) and reaction times (p=0.006) to the vehicle incursion. These findings suggest that our simulator training program is feasible and potentially useful in drivers with PD. Future research questions include transfer of training to different driving tasks, duration of benefit, and the effect on long term real life outcomes in comparison to a standard intervention (e.g., driver education class) in a randomized trial. PMID:24273752

Improvement in Brightness Uniformity by Compensating for the Threshold Voltages of Both the Driving Thin-Film Transistor and the Organic Light-Emitting Diode for Active-Matrix Organic Light-Emitting Diode Displays

NASA Astrophysics Data System (ADS)

Ching-Lin Fan,; Hui-Lung Lai,; Jyu-Yu Chang,

2010-05-01

In this paper, we propose a novel pixel design and driving method for active-matrix organic light-emitting diode (AM-OLED) displays using low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs). The proposed threshold voltage compensation circuit, which comprised five transistors and two capacitors, has been verified to supply uniform output current by simulation work using the automatic integrated circuit modeling simulation program with integrated circuit emphasis (AIM-SPICE) simulator. The driving scheme of this voltage programming method includes four periods: precharging, compensation, data input, and emission. The simulated results demonstrate excellent properties such as low error rate of OLED anode voltage variation (<1%) and high output current. The proposed pixel circuit shows high immunity to the threshold voltage deviation characteristics of both the driving poly-Si TFT and the OLED.

Functional strategies drive community assembly of stream fishes along environmental gradients and across spatial scales

DOE Office of Scientific and Technical Information (OSTI.GOV)

Troia, Matthew J.; Gido, Keith B.

Trade-offs among functional traits produce multi-trait strategies that shape species interactions with the environment and drive the assembly of local communities from regional species pools. Stream fish communities vary along stream size gradients and among hierarchically structured habitat patches, but little is known about how the dispersion of strategies varies along environmental gradients and across spatial scales. We used null models to quantify the dispersion of reproductive life history, feeding, and locomotion strategies in communities sampled at three spatial scales in a prairie stream network in Kansas, USA. Strategies were generally underdispersed at all spatial scales, corroborating the longstanding notionmore » of abiotic filtering in stream fish communities. We tested for variation in strategy dispersion along a gradient of stream size and between headwater streams draining different ecoregions. Reproductive life history strategies became increasingly underdispersed moving from downstream to upstream, suggesting that abiotic filtering is stronger in headwaters. This pattern was stronger among reaches compared to mesohabitats, supporting the premise that differences in hydrologic regime among reaches filter reproductive life history strategies. Feeding strategies became increasingly underdispersed moving from upstream to downstream, indicating that environmental filters associated with stream size affect the dispersion of feeding and reproductive life history in opposing ways. Weak differences in strategy dispersion were detected between ecoregions, suggesting that different abiotic filters or strategies drive community differences between ecoregions. Lastly, given the pervasiveness of multi-trait strategies in plant and animal communities, we conclude that the assessment of strategy dispersion offers a comprehensive approach for elucidating mechanisms of community assembly.« less

Medium Duty ARRA Data Reporting and Analysis; NREL (National Renewable Energy Laboratory)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kelly, Kenneth; Duran, Adam; Ragatz, Adam

Medium-duty (MD) electric vehicle (EV) data collection and analysis will help drive design, purchase, and research investments. Over 4 million miles and 160,000 driving days of EV driving data were collected under this project. Publicly available data help drive technology research, development, and deployment. Feeding the vocational database for future analysis will lead to a better understanding of usage and will result in better design optimization and technology implementation. The performance of a vehicle varies with drive cycle and cargo load - MD vehicles are 'multi-functional.' Environment and accessory loads affect vehicle range and in turn add cost by addingmore » battery capacity. MD EV vehicles can function in vocations traditionally serviced by gasoline or diesel vehicles. Facility implications (i.e., demand charges) need to be understood as part of site-based analysis for EV implementation.« less

The application of quasi-steady approximation in atomic kinetics in simulation of hohlraum radiation drive

NASA Astrophysics Data System (ADS)

Ren, Guoli; Pei, Wenbing; Lan, Ke; Gu, Peijun; Li, Xin; Institute of Applied Physics; Computional Mathematics Team

2011-10-01

In current routine 2D simulation of hohlraum physics, we adopt the principal-quantum- number(n-level) average atom model(AAM). However, the experimental frequency-dependant radiative drive differs from our n-level simulated drive, which reminds us the need of a more detailed atomic kinetics description. The orbital-quantum-number(nl-level) AAM is a natural consideration but the in-line calculation consumes much more resources. We use a new method to built up a nl-level bound electron distribution using in-line n-level calculated plasma condition (such as temperature, density, average ionization degree). We name this method ``quasi-steady approximation.'' Using the re-built nl-level bound electron distribution (Pnl) , we acquire a new hohlraum radiative drive by post-processing. Comparison with the n-level post-processed hohlraum drive shows that we get an almost identical radiation flux but with more-detailed frequency-dependant structures.

Useful field of view in simulated driving: Reaction times and eye movements of drivers

PubMed Central

Seya, Yasuhiro; Nakayasu, Hidetoshi; Yagi, Tadasu

2013-01-01

To examine the spatial distribution of a useful field of view (UFOV) in driving, reaction times (RTs) and eye movements were measured in simulated driving. In the experiment, a normal or mirror-reversed letter “E” was presented on driving images with different eccentricities and directions from the current gaze position. The results showed significantly slower RTs in the upper and upper left directions than in the other directions. The RTs were significantly slower in the left directions than in the right directions. These results suggest that the UFOV in driving may be asymmetrical among the meridians in the visual field. PMID:24349688

Design of driving control strategy of torque distribution for two - wheel independent drive electric vehicle

NASA Astrophysics Data System (ADS)

Zhang, Chuanwei; Zhang, Dongsheng; Wen, Jianping

2018-02-01

In order to coordinately control the torque distribution of existing two-wheel independent drive electric vehicle, and improve the energy efficiency and control stability of the whole vehicle, the control strategies based on fuzzy control were designed which adopt the direct yaw moment control as the main line. For realizing the torque coordination simulation of the two-wheel independent drive vehicle, the vehicle model, motor model and tire model were built, including the vehicle 7 - DOF dynamics model, motion equation, torque equation. Finally, in the Carsim - Simulink joint simulation platform, the feasibility of the drive control strategy was verified.

VTI Driving Simulator: Mathematical Model of a Four-wheeled Vehicle for Simulation in Real Time. VTI Rapport 267A.

ERIC Educational Resources Information Center

Nordmark, Staffan

1984-01-01

This report contains a theoretical model for describing the motion of a passenger car. The simulation program based on this model is used in conjunction with an advanced driving simulator and run in real time. The mathematical model is complete in the sense that the dynamics of the engine, transmission and steering system is described in some…

Falls Risk and Simulated Driving Performance in Older Adults

PubMed Central

Gaspar, John G.; Neider, Mark B.; Kramer, Arthur F.

2013-01-01

Declines in executive function and dual-task performance have been related to falls in older adults, and recent research suggests that older adults at risk for falls also show impairments on real-world tasks, such as crossing a street. The present study examined whether falls risk was associated with driving performance in a high-fidelity simulator. Participants were classified as high or low falls risk using the Physiological Profile Assessment and completed a number of challenging simulated driving assessments in which they responded quickly to unexpected events. High falls risk drivers had slower response times (~2.1 seconds) to unexpected events compared to low falls risk drivers (~1.7 seconds). Furthermore, when asked to perform a concurrent cognitive task while driving, high falls risk drivers showed greater costs to secondary task performance than did low falls risk drivers, and low falls risk older adults also outperformed high falls risk older adults on a computer-based measure of dual-task performance. Our results suggest that attentional differences between high and low falls risk older adults extend to simulated driving performance. PMID:23509627

The dragnet of children's feeding programs in Atlantic Canada.

PubMed

Dayle, J B; McIntyre, L; Raine-Travers, K D

2000-12-01

Ivan Illich's 1976 prediction that medical dragnets will continue was correct. Now quasi-health dragnets are being established ostensibly to feed children perceived to be hungry. Our qualitative, multi-site case study found that programs justify their expansion to non-target group children as a means of reducing stigmatization, while reaching only an estimated one-third of targeted children. The dragnet continues as new services are added and franchising is proposed while the purpose of the program feeding healthy foods to children ultimately succumbs to drives for efficiency and the desire to maintain the program itself. In this field of social power relations, children become commodified through dialectical interplays among fundamental needs, manipulated needs, benevolence, and domination.

Simulated Driving Performance of Adults with ADHD: Comparisons with Alcohol Intoxication

PubMed Central

Weafer, Jessica; Camarillo, Daniel; Fillmore, Mark T.; Milich, Richard; Marczinski, Cecile A.

2015-01-01

Previous research has demonstrated that adults with ADHD are more likely to experience driving-related problems, which suggests that they may exhibit poorer driving performance. However, direct experimental evidence of this hypothesis is limited. The current study involved two experiments that evaluated driving performance in adults with ADHD in terms of the types of driving decrements typically associated with alcohol intoxication. Experiment 1 compared the simulated driving performance of 15 adults with ADHD to 23 adult control participants, who performed the task both while sober and intoxicated. Results showed that sober adults with ADHD exhibited decrements in driving performance compared to sober controls, and that the profile of impairment for the sober ADHD group did in fact resemble that of intoxicated drivers at the BAC level for legally impaired driving in the United States. Driving impairment of the intoxicated individuals was characterized by greater deviation of lane position, faster and more abrupt steering maneuvers, and increased speed variability. Experiment 2 was a dose-challenge study in which 8 adults with ADHD and 8 controls performed the driving simulation task under three doses of alcohol: 0.65 g/kg, 0.45 g/kg, and 0.0 g/kg (placebo). Results showed that driving performance in both groups was impaired in response to alcohol, and that individuals with ADHD exhibited generally poorer driving performance than did controls across all dose conditions. Together the findings provide compelling evidence to suggest that the cognitive and behavioral deficits associated with ADHD might impair driving performance in such a manner as to resemble that of an alcohol intoxicated driver. Moreover, alcohol might impair the performance of drivers with ADHD in an additive fashion that could considerably compromise their driving skill even at blood alcohol concentrations below the legal limit. PMID:18540785

Temporal profile of prolonged, night-time driving performance: breaks from driving temporarily reduce time-on-task fatigue but not sleepiness.

PubMed

Phipps-Nelson, Jo; Redman, Jennifer R; Rajaratnam, Shantha M W

2011-09-01

Breaks are often used by drivers to counteract sleepiness and time-on-task fatigue during prolonged driving. We examined the temporal profile of changes in driving performance, electroencephalogram (EEG) activity and subjective measures of sleepiness and fatigue during prolonged nocturnal driving in a car simulator. In addition, the study examined the impact of regular breaks from driving on performance, sleepiness and fatigue. Healthy volunteers (n=12, 23-45 years) maintained a regular sleep-wake pattern for 14 days and were then in a laboratory from 21:00 to 08:30 hours. The driving simulator scene was designed to simulate monotonous night-time rural driving. Participants drove 4 × 2-h test sessions, with a break from driving of 1 h between each session. During the break participants performed tests assessing sleepiness and fatigue, and psychomotor performance (~30 mins), and then were permitted to sit quietly. They were monitored for wakefulness, and not permitted to nap or ingest caffeine. EEG was recorded during the driving task, and subjective assessments of sleepiness and fatigue were obtained at the start and completion of each session. We found that driving performance deteriorated (2.5-fold), EEG delta, theta and alpha activity increased, and subjective sleepiness and fatigue ratings increased across the testing period. Driving performance and fatigue ratings improved following the scheduled breaks from driving, while the breaks did not affect EEG activity and subjective sleepiness. Time-on-task effects increased through the testing period, indicating that these effects are exacerbated by increasing sleepiness. Breaks from driving without sleep temporarily ameliorate time-on-task fatigue, but provide little benefit to the sleepy driver. © 2010 European Sleep Research Society.

Driver Training Simulator for Backing Up Commercial Vehicles with Trailers

NASA Astrophysics Data System (ADS)

Berg, Uwe; Wojke, Philipp; Zöbel, Dieter

Backing up tractors with trailers is a difficult task since the kinematic behavior of articulated vehicles is complex and hard to control. Especially unskilled drivers are overstrained with the complicated steering process. To learn and practice the steering behavior of articulated vehicles, we developed a 3D driving simulator. The simulator can handle different types of articulated vehicles like semi-trailers, one- and two-axle trailers, or gigaliners. The use of a driving simulator offers many advantages over the use of real vehicles. One of the main advantages is the possibility to learn the steering behavior of all vehicle types. Drivers can be given more and better driving instructions like collision warnings or steering hints. Furthermore, the driver training costs can be reduced. Moreover, mistakes of the student do not lead to real damages and costly repairs. The hardware of the simulator consists of a low cost commercial driving stand with original truck parts, a projection of the windshield and two flat panel monitors for the left and right exterior mirrors. Standard PC hardware is used for controlling the driving stand and for generating the realtime 3D environment. Each aspect of the simulation like realistic vehicle movements or generation of different views, is handled by a specific software module. This flexible system can be easily extended which offers the opportunity for other uses than just driver training. Therefore, we use the simulator for the development and test of driver assistance systems.

Actual and simulated injury of Creontiades signatus (Heteroptera: Miridae) feeding on cotton bolls

USDA-ARS?s Scientific Manuscript database

The actual feeding injury of Creontiades signatus (Distant) was compared to a simulated technique for study years 2005, 2006 and 2008 by injecting varying dilutions of pectinase into cotton bolls at different boll sizes (ages) in an effort to determine if such a technique could be used to reduce the...

Using a bioenergetic model to assess growth reduction from catch-and-release fishing and hooking injury in rainbow trout, Oncorhynchus mykiss

USGS Publications Warehouse

Meka, Julie M.; Margraf, F.J.

2007-01-01

A bioenergetic model was used to predict the potential effects of feeding cessation caused by catch-and-release capture and a reduction in feeding efficiency from hooking injuries on rainbow trout, Oncorhynchus mykiss (Walbaum), growth in southwest Alaska, USA. Simulations indicated that a 1-day feeding cessation for a rainbow trout captured one to two times during summer months resulted in deviations from expected growth of −3% to −15%. To represent debilitating hooking injuries, the proportion of the maximum feeding potential was decreased by 5–50% resulting in deviations from expected growth of −9% to −164%. Simulated growth effects were most prominent from captures during months when salmon eggs and flesh constituted the majority of the trout diet. Simulated growth effects from reduced foraging efficiency were most prominent when hooking injuries occurred early in the fishing season. These simulations suggest that rainbow trout are most vulnerable to decreases in growth when salmon are abundant and spawning and, coincidentally, during the months when most fishing occurs.

An ultra-low-cost moving-base driving simulator

DOT National Transportation Integrated Search

2001-11-04

A novel approach to driving simulation is described, one that potentially overcomes the limitations of both motion fidelity and cost. It has become feasible only because of recent advances in computer-based image generation speed and fidelity and in ...

A study on optimization of hybrid drive train using Advanced Vehicle Simulator (ADVISOR)

NASA Astrophysics Data System (ADS)

Same, Adam; Stipe, Alex; Grossman, David; Park, Jae Wan

This study investigates the advantages and disadvantages of three hybrid drive train configurations: series, parallel, and "through-the-ground" parallel. Power flow simulations are conducted with the MATLAB/Simulink-based software ADVISOR. These simulations are then applied in an application for the UC Davis SAE Formula Hybrid vehicle. ADVISOR performs simulation calculations for vehicle position using a combined backward/forward method. These simulations are used to study how efficiency and agility are affected by the motor, fuel converter, and hybrid configuration. Three different vehicle models are developed to optimize the drive train of a vehicle for three stages of the SAE Formula Hybrid competition: autocross, endurance, and acceleration. Input cycles are created based on rough estimates of track geometry. The output from these ADVISOR simulations is a series of plots of velocity profile and energy storage State of Charge that provide a good estimate of how the Formula Hybrid vehicle will perform on the given course. The most noticeable discrepancy between the input cycle and the actual velocity profile of the vehicle occurs during deceleration. A weighted ranking system is developed to organize the simulation results and to determine the best drive train configuration for the Formula Hybrid vehicle. Results show that the through-the-ground parallel configuration with front-mounted motors achieves an optimal balance of efficiency, simplicity, and cost. ADVISOR is proven to be a useful tool for vehicle power train design for the SAE Formula Hybrid competition. This vehicle model based on ADVISOR simulation is applicable to various studies concerning performance and efficiency of hybrid drive trains.

Learning Temporal Patterns of Risk in a Predator-Diverse Environment

PubMed Central

Bosiger, Yoland J.; Lonnstedt, Oona M.; McCormick, Mark I.; Ferrari, Maud C. O.

2012-01-01

Predation plays a major role in shaping prey behaviour. Temporal patterns of predation risk have been shown to drive daily activity and foraging patterns in prey. Yet the ability to respond to temporal patterns of predation risk in environments inhabited by highly diverse predator communities, such as rainforests and coral reefs, has received surprisingly little attention. In this study, we investigated whether juvenile marine fish, Pomacentrus moluccensis (lemon damselfish), have the ability to learn to adjust the intensity of their antipredator response to match the daily temporal patterns of predation risk they experience. Groups of lemon damselfish were exposed to one of two predictable temporal risk patterns for six days. “Morning risk” treatment prey were exposed to the odour of Cephalopholis cyanostigma (rockcod) paired with conspecific chemical alarm cues (simulating a rockcod present and feeding) during the morning, and rockcod odour only in the evening (simulating a rockcod present but not feeding). “Evening risk” treatment prey had the two stimuli presented to them in the opposite order. When tested individually for their response to rockcod odour alone, lemon damselfish from the morning risk treatment responded with a greater antipredator response intensity in the morning than in the evening. In contrast, those lemon damselfish previously exposed to the evening risk treatment subsequently responded with a greater antipredator response when tested in the evening. The results of this experiment demonstrate that P. moluccensis have the ability to learn temporal patterns of predation risk and can adjust their foraging patterns to match the threat posed by predators at a given time of day. Our results provide the first experimental demonstration of a mechanism by which prey in a complex, multi-predator environment can learn and respond to daily patterns of predation risk. PMID:22493699

Engineering of Impulse Mechanism for Mechanical Hander Power Tools

NASA Astrophysics Data System (ADS)

Nikolaevich Drozdov, Anatoliy

2018-03-01

The solution to the problem of human security in cities should be considered on the basis of an integrated and multidisciplinary approach, including issues of security and ecology in the application of technical means used to ensure the viability and development of technocracy. In this regard, an important task is the creation of a safe technique with improved environmental properties with high technological characteristics. This primarily relates to mechanised tool — the division of technological machines with built in engines is that their weight is fully or partially perceived by the operator’s hands, making the flow and control of the car. For this subclass of machines is characterized by certain features: a built-in motor, perception of at least part of their weight by the operator during the work, the implementation of feeding and management at the expense of the muscular power of the operator. Therefore, among the commonly accepted technical and economic characteristics, machines in this case, important ergonomic (ergonomics), regulation of levels which ensures the safety of the operator. To ergonomics include vibration, noise characteristics, mass, and force feeding machine operator. Vibration is a consequence of the dynamism of the system operator machine - processed object (environment) in which the engine energy is redistributed among all the structures, causing their instability. In the machine vibration caused by technological and constructive (transformative mechanisms) unbalance of individual parts of the drive, the presence of technological and design (impact mechanisms) clearances and other reasons. This article describes a new design of impulse mechanism for hander power tools (wrenches, screwdrivers) with enhanced torque. The article substantiates a simulation model of dynamic compression process in an operating chamber during impact, provides simulation results and outlines further lines of research.

Evaluating and Enhancing Driving Ability Among Teens with Autism Spectrum Disorder (ASD)

DTIC Science & Technology

2014-10-01

able to engage in the driving training, and none have experienced simulation adaptation syndrome. 15. SUBJECT TERMS Autism, Driving Safety , Driving...routine driving training (RT) required by the DMV, VRDS training + RT (VRDS-T) would lead to greater improvement in driving safety and less driving...improved driving safety above and beyond RT. We hypothesized that computer-generated feedback would be more palatable than human-generated feedback to

Driving safety in Parkinson's disease.

PubMed

Zesiewicz, T A; Cimino, C R; Malek, A R; Gardner, N; Leaverton, P L; Dunne, P B; Hauser, R A

2002-12-10

In this study, 39 patients with PD and 25 control subjects without neurologic disease completed testing in a driving simulator. PD patients had more total collisions on the driving simulator than control subjects (t = -3.7, p < 0.01). In PD patients, collisions were associated with Hoehn and Yahr stage (chi(2) = 12.4, p = 0.006) and correlated with Unified Parkinson's Disease Rating Scale score (r = 0.5, p < 0.01).

Driving with a short arm cast in a simulator.

PubMed

Mansour, Damian; Mansour, Kristin Gotaas; Kenny, Benjamin William; Attia, John; Meads, Bryce

2015-12-01

To test the ability to steer in a driving simulator in subjects with a short arm cast. 17 men and 13 women aged 23 to 67 (mean, 37) years who had a valid driver's licence were randomised to the cast-first group (n=16; 7 had the cast on the dominant arm) or the cast-second group (n=14; 8 had the cast on the dominant arm) and drove in a simulator. A short arm plaster-of-Paris cast was applied in a neutral position, allowing free movement of the metacarpophalangeal joints, thumb, and elbow joint. Outcome measures included the number of driving off track instances, the number of crashes, the lap time, and the effect of hand dominance on these parameters. Subjects were asked whether the cast had impeded their steering ability. Subjects with or without a cast were comparable in terms of the number of driving off track instances, number of crashes, and lap time. Compared with no cast, the odds ratio (OR) of a subject in a cast driving off the track was 1.02 (p=0.921) and having a crash was 0.79 (p=0.047). All subjects were 1.23 times more likely to drive off the track in their first lap (OR=2.66, p=0.019). The mean lap time decreased for each consecutive lap from the 2nd to 5th laps. Subjects driving with a cast on the dominant or non-dominant arm were comparable. 26 out of the 30 participants considered that the plaster cast impeded their steering ability. Compared with no cast, driving with a short arm cast did not significantly decrease steering ability in a driving simulator.

A Prospective Study of Loss of Consciousness in Epilepsy Using Virtual Reality Driving Simulation and Other Video Games

PubMed Central

Yang, Li; Morland, Thomas B.; Schmits, Kristen; Rawson, Elizabeth; Narasimhan, Poojitha; Motelow, Joshua E.; Purcaro, Michael J.; Peng, Kathy; Raouf, Saned; DeSalvo, Matthew N.; Oh, Taemin; Wilkerson, Jerome; Bod, Jessica; Srinivasan, Aditya; Kurashvili, Pimen; Anaya, Joseph; Manza, Peter; Danielson, Nathan; Ransom, Christopher B.; Huh, Linda; Elrich, Susan; Padin-Rosado, Jose; Naidu, Yamini; Detyniecki, Kamil; Hamid, Hamada; Fattahi, Pooia; Astur, Robert; Xiao, Bo; Duckrow, Robert B.; Blumenfeld, Hal

2010-01-01

Patients with epilepsy are at risk of traffic accidents when they have seizures while driving. However, driving is an essential part of normal daily life in many communities, and depriving patients of driving privileges can have profound consequences for their economic and social well being. In the current study, we collected ictal performance data from a driving simulator and two other video games in patients undergoing continuous video/EEG monitoring. We captured 22 seizures in 13 patients and found that driving impairment during seizures differed both in terms of magnitude and character, depending on the seizure type. Our study documents the feasibility of the prospective study of driving and other behaviors during seizures through the use of computer-based tasks. This methodology may be applied to further describe differential driving impairment in specific types of seizures and to gain data on anatomical networks disrupted in seizures that impair consciousness and driving safety. PMID:20537593

Rapid Drinking is Associated with Increases in Driving-Related Risk-Taking

PubMed Central

Bernosky-Smith, Kimberly A.; Aston, Elizabeth R.; Liguori, Anthony

2014-01-01

Objective The rate of alcohol drinking has been shown to predict impairment on cognitive and behavioral tasks. The current study assessed the influence of speed of alcohol consumption within a laboratory-administered binge on self-reported attitudes toward driving and simulated driving ability. Method Forty moderate drinkers (20 female, 20 male) were recruited from the local community via advertisements for individuals who drank alcohol at least once per month. The equivalent of four standard alcohol drinks was consumed at the participant’s desired pace within a two-hour session. Results Correlation analyses revealed that, after alcohol drinking, mean simulated driving speed, time in excess of speed limit, collisions, and reported confidence in driving were all associated with rapid alcohol drinking. Conclusion Fast drinking may coincide with increased driving confidence due to the extended latency between the conclusion of drinking and the commencement of driving. However, this latency did not reduce alcohol-related driving impairment, as fast drinking was also associated with risky driving. PMID:23027650

Rapid drinking is associated with increases in driving-related risk-taking.

PubMed

Bernosky-Smith, Kimberly A; Aston, Elizabeth R; Liguori, Anthony

2012-11-01

The rate of alcohol drinking has been shown to predict impairment on cognitive and behavioral tasks. The current study assessed the influence of speed of alcohol consumption within a laboratory-administered binge on self-reported attitudes toward driving and simulated driving ability. Forty moderate drinkers (20 female, 20 male) were recruited from the local community via advertisements for individuals who drank alcohol at least once per month. The equivalent of four standard alcohol drinks was consumed at the participant's desired pace within 2-h session. Correlation analyses revealed that, after alcohol drinking, mean simulated driving speed, time in excess of speed limit, collisions, and reported confidence in driving were all associated with rapid alcohol drinking. Fast drinking may coincide with increased driving confidence because of the extended latency between the conclusion of drinking and the commencement of driving. However, this latency did not reduce alcohol-related driving impairment, as fast drinking was also associated with risky driving. Copyright © 2012 John Wiley & Sons, Ltd.

Cognitive Functioning and Driving Simulator Performance in Middle-aged and Older Adults with HIV

PubMed Central

Vance, David E.; Fazeli, Pariya L.; Ball, David A.; Slater, Larry Z.; Ross, Lesley A.

2014-01-01

Nearly half of people living with HIV experience cognitive deficits that may impact instrumental activities of daily living. As the number of people aging with HIV increases, concerns mount that disease-related cognitive deficits may be compounded by age-related deficits, which may further compromise everyday functions such as driving. In this cross-sectional pilot study, during a 2.5-hour visit, 26 middle-aged and older adults (40+ years) were administered demographic, health, psychosocial, and driving habits questionnaires; cognitive assessments; and driving simulator tests. Although CD4+T lymphocyte count and viral load were unrelated to driving performance, older age was related to poorer driving. Furthermore, poorer visual speed of processing performance (i.e., Useful Field of View) was related to poorer driving performance (e.g., average gross reaction time). Mixed findings were observed between driving performance and cognitive function on self-reported driving habits of participants. Implications for these findings on nursing practice and research are posited. PMID:24513104

Comparison of driving simulator performance and neuropsychological testing in narcolepsy.

PubMed

Kotterba, Sylvia; Mueller, Nicole; Leidag, Markus; Widdig, Walter; Rasche, Kurt; Malin, Jean-Pierre; Schultze-Werninghaus, Gerhard; Orth, Maritta

2004-09-01

Daytime sleepiness and cataplexy can increase automobile accident rates in narcolepsy. Several countries have produced guidelines for issuing a driving license. The aim of the study was to compare driving simulator performance and neuropsychological test results in narcolepsy in order to evaluate their predictive value regarding driving ability. Thirteen patients with narcolepsy (age: 41.5+/-12.9 years) and 10 healthy control patients (age: 55.1+/-7.8 years) were investigated. By computer-assisted neuropsychological testing, vigilance, alertness and divided attention were assessed. In a driving simulator patients and controls had to drive on a highway for 60 min (mean speed of 100 km/h). Different weather and daytime conditions and obstacles were presented. Epworth Sleepiness Scale-Scores were significantly raised (narcolepsy patients: 16.7+/-5.1, controls: 6.6+/-3.6, P < or = 0.001). The accident rate of the control patients increased (3.2+/-1.8 versus 1.3+/-1.5, P < or = 0.01). Significant differences in concentration lapses (e.g. tracking errors and deviation from speed limit) could not be revealed (9.8+/-3.5 versus 7.1+/-3.2, pns). Follow-up investigation in five patients after an optimising therapy could demonstrate the decrease in accidents due to concentration lapses (P < or = 0.05). Neuropsychological testing (expressed as percentage compared to a standardised control population) revealed deficits in alertness (32.3+/-28.6). Mean percentage scores of divided attention (56.9+/-25.4) and vigilance (58.7+/-26.8) were in a normal range. There was, however, a high inter-individual difference. There was no correlation between driving performance and neuropsychological test results or ESS Score. Neuropsychological test results did not significantly change in the follow-up. The difficulties encountered by the narcolepsy patient in remaining alert may account for sleep-related motor vehicle accidents. Driving simulator investigations are closely related to real traffic situations than isolated neuropsychological tests. At the present time the driving simulator seems to be a useful instrument judging driving ability especially in cases with ambiguous neuropsychological results.

Effects of armodafinil on simulated driving and alertness in shift work disorder.

PubMed

Drake, Christopher; Gumenyuk, Valentina; Roth, Thomas; Howard, Ryan

2014-12-01

Forty-one percent of shift workers report dozing while driving. This study tested whether armodafinil improves driving simulator performance in subjects with shift work disorder (SWD). A primary outcome was performance late in the shift when workers are typically driving home. Randomized, double-blind, crossover. During each 12-h test session (21:30-09:30), subjects were kept awake except for multiple sleep latency testing (MSLT: 01:30, 03:30, 05:30, and 07:30). Subjective sleepiness (Karolinska Sleepiness Scale, KSS), driving performance, and cognitive performance (digit symbol substitution test and creativity on the Remote Associates Test, RAT) were evaluated during the night shift and commute home times. Hospital-based sleep research laboratory. Twenty night workers (age: 42.7 ± 8.7 y, 17 F) with excessive sleepiness (≥ 10 on the Epworth Sleepiness Scale), meeting International Classification of Sleep Disorders, Second Edition (ICSD-2) criteria for SWD, and having no other medical conditions. Armodafinil (150 mg) or placebo at (23:45 h) on counterbalanced nights separated by 7-14 days. Primary endpoints were driving simulator performance (standard deviation of lateral position (SDLP) and off-road deviations) with four sessions starting 3.25 h after drug administration, objective sleepiness (MSLT; 1.75 to 7.75 h post-drug), and creativity (5 h post-drug). Significant effects of drug were observed for each driving measure (P < 0.05). Armodafinil significantly improved SDLP for simulator sessions at 05:30, 07:30, and 09:30, and off-road deviations at 7 h, 15 min and 9 h, 15 min post-drug (P < 0.05). Armodafinil also improved objective sleepiness from 3.7 ± 0.6 min to 9.7 ± 5.2 min (P < 0.001) and RAT score from 8.75 ± 4.9 to 11.25 ± 6.0 (P < 0.005). Armodafinil 150 mg early in the night shift improves driving simulator performance in SWD. Effects on sleepiness, cognition, and driving were found up to 9.5 h post-ingestion, during the critical time when many night workers are driving home. © 2014 Associated Professional Sleep Societies, LLC.

National energy efficient driving system (NEEDS). Volume 3, Home vehicle use study

DOT National Transportation Integrated Search

1981-12-15

Eight vehicles were instrumented to permit travel distance and fuel consumption to be measured. Following the collection of baseline measures, three different systems were provided to feed back distance and fuel information to drivers: manual, a week...

Covert Hepatic Encephalopathy: Can My Patient Drive?

PubMed Central

Shaw, Jawaid; Bajaj, Jasmohan S

2016-01-01

Liver cirrhosis is a public health problem and hepatic encephalopathy (HE) is one of its main complications, which can be either overt meaning thereby evident and readily diagnosed, or covert/minimal (CHE) needing psychometric testing for diagnosis. Patients with CHE hepatic encephalopathy have deficits in multiple domains including visuo-spatial assessment, attention, response inhibition, working memory, along with psychomotor speed to name a few areas. These patients have poor navigational skills, get fatigued easily and demonstrate poor insight into their driving deficits. The combination of all these leads them to have poor driving skills leading to traffic violations and crashes as demonstrated not only on the simulation testing but also in real life driving events. There are multiple psychometric tests for CHE testing but these are not easily available and there is no uniform consensus on the gold standard testing as of yet. It does not automatically connote that all patients who test positive on driving simulation testing are unfit to drive. The physicians are encouraged to take driving history from the patient and the care- givers on every encounter and focus their counseling efforts more on patients with recent history of traffic crashes, with abnormal simulation studies and history of alcohol cessation within last year. As physicians are not trained to determine fitness to drive, their approach towards CHE patients in regards to driving restrictions should be driven by ethical principles while as respecting the local laws. PMID:28027071

Effects of valerian on subjective sedation, field sobriety testing and driving simulator performance.

PubMed

Thomas, Kelan; Canedo, Joanne; Perry, Paul J; Doroudgar, Shadi; Lopes, Ingrid; Chuang, Hannah Mae; Bohnert, Kimberly

2016-07-01

The availability of herbal medicines over-the-counter (OTC) has increased the use of natural products for self-treatment. Valerian has been used to effectively treat generalized anxiety disorder and insomnia. Studies suggest that valerenic acid may increase gamma-aminobutyric acid (GABA) modulation in the brain. Benzodiazepines have a similar mechanism of action and have been linked to an increased risk of hospitalizations due to traffic accidents. Despite the risk of somnolence, the safety of driving while under the influence of valerian remains unknown. The purpose of the study was to determine the effects of a one-time valerian 1600mg dose on subjective sedation effects, standardized field sobriety testing (SFST) and driving simulator performance parameters. The study design was a randomized, placebo-controlled, double-blind, cross-over trial. For each session, participants received either a dose of valerian or placebo. The outcome measures included a simple visual reaction test (SVRT), subjective sleepiness scales, SFST performance scores, and driving simulator performance parameters. There were no significant differences in the SVRT or sleepiness scales between placebo and valerian exposures, but the study may have been underpowered. SFST total and individual test failure rates were not significantly different between the two exposures. The driving simulator performance parameters were equivalent between the two exposure conditions. A one-time valerian 1600mg dose, often used to treat insomnia, does not appear to impair driving simulator performance after acute ingestion. Copyright © 2016 Elsevier Ltd. All rights reserved.

Driving Simulator Performance in Patients with Possible and Probable Alzheimer’s Disease

PubMed Central

Stein, Anthony C.; Dubinsky, Richard M.

2011-01-01

Drivers with more advanced stages of Alzheimer’s disease (AD) have been previously associated with an increased rate of motor vehicle accidents. Drivers suffering from early AD are also involved in, and may even cause motor vehicle accidents with greater frequency than “normal” drivers. Consequently there is considerable public concern regarding traffic safety issues for those with AD and subsequently for society, but there has been little research in understanding whether deterioration in driving ability is progressive, or has a sudden onset once the disease has reached a certain severity. The purpose of this study was to identify possible degradation in simulated driving performance that may occur at the earliest stages of AD, and compare these decrements to a control group of normal drivers. Using a single blind design, seventeen AD subjects, eight at a Clinical Dementia Rating (CDR) of 0.5 (possible AD) and nine at a CDR of 1 (probable AD), were compared to 63 cognitively normal, elderly controls. All subjects were trained to drive a computerized interactive driving simulator and then tested on a 19.3 km (12 mile) test course. The AD subjects demonstrated impaired driving performance when compared to the controls. The simulated driving performance of the CDR 1 AD subjects was so degraded that it would be regarded as unsafe by standard assessment criteria. The CDR 0.5 subjects made similar errors, suggesting that driving impairment may occur at the earliest stages of the disease. Further work will be necessary to determine the significance of these findings. PMID:22105407

Mechanical-thermal noise in drive-mode of a silicon micro-gyroscope.

PubMed

Yang, Bo; Wang, Shourong; Li, Hongsheng; Zhou, Bailing

2009-01-01

A new closed-loop drive scheme which decouples the phase and the gain of the closed-loop driving system was designed in a Silicon Micro-Gyroscope (SMG). We deduce the system model of closed-loop driving and use stochastic averaging to obtain an approximate "slow" system that clarifies the effect of thermal noise. The effects of mechanical-thermal noise on the driving performance of the SMG, including the noise spectral density of the driving amplitude and frequency, are derived. By calculating and comparing the noise amplitude due to thermal noise both in the opened-loop driving and in the closed-loop driving, we find that the closed-loop driving does not reduce the RMS noise amplitude. We observe that the RMS noise frequency can be reduced by increasing the quality factor and the drive amplitude in the closed-loop driving system. The experiment and simulation validate the feasibility of closed-loop driving and confirm the validity of the averaged equation and its stablility criterion. The experiment and simulation results indicate the electrical noise of closed-loop driving circuitry is bigger than the mechanical-thermal noise and as the driving mass decreases, the mechanical-thermal noise may get bigger than the electrical noise of the closed-loop driving circuitry.

Fear of the human 'super predator' reduces feeding time in large carnivores.

PubMed

Smith, Justine A; Suraci, Justin P; Clinchy, Michael; Crawford, Ayana; Roberts, Devin; Zanette, Liana Y; Wilmers, Christopher C

2017-06-28

Large carnivores' fear of the human 'super predator' has the potential to alter their feeding behaviour and result in human-induced trophic cascades. However, it has yet to be experimentally tested if large carnivores perceive humans as predators and react strongly enough to have cascading effects on their prey. We conducted a predator playback experiment exposing pumas to predator (human) and non-predator control (frog) sounds at puma feeding sites to measure immediate fear responses to humans and the subsequent impacts on feeding. We found that pumas fled more frequently, took longer to return, and reduced their overall feeding time by more than half in response to hearing the human 'super predator'. Combined with our previous work showing higher kill rates of deer in more urbanized landscapes, this study reveals that fear is the mechanism driving an ecological cascade from humans to increased puma predation on deer. By demonstrating that the fear of humans can cause a strong reduction in feeding by pumas, our results support that non-consumptive forms of human disturbance may alter the ecological role of large carnivores. © 2017 The Author(s).

Relationship between workload and mind-wandering in simulated driving

PubMed Central

2017-01-01

Mental workload and mind-wandering are highly related to driving safety. This study investigated the relationship between mental workload and mind-wandering while driving. Participants (N = 40) were asked to perform a car following task in driving simulator, and report whether they had experienced mind-wandering upon hearing a tone. After driving, participants reported their workload using the NASA-Task Load Index (TLX). Results revealed an interaction between workload and mind-wandering in two different perspectives. First, there was a negative correlation between workload and mind-wandering (r = -0.459, p < 0.01) for different individuals. Second, from temporal perspective workload and mind-wandering frequency increased significantly over task time and were positively correlated. Together, these findings contribute to understanding the roles of workload and mind-wandering in driving. PMID:28467513

Correlation between Driver Subjective Fatigue and Bus Lateral Position in a Driving Simulator.

PubMed

Gharagozlou, Faramarz; Mazloumi, Adel; Saraji, Gebraeil Nasl; Nahvi, Ali; Ashouri, Mohammadreza; Mozaffari, Hamed

2015-08-01

Driver fatigue as a leading cause of death in the transportation industry can impair the driving performance in long-distance driving task. Studies on the links of driver subjective fatigue and the bus lateral position are still an exploratory issue that requires further investigation. This study aimed to determine the correlation between the driver subjective fatigue and the bus lateral position in a driving simulator. This descriptive-analytical research was conducted on 30 professional male bus drivers participated in a two-hour driving session. The driver subjective fatigue was assessed by the Fatigue Visual Analogue Scale (F-VAS) at 10-min intervals. Simultaneously, the performance measures of lane drifting as the mean and standard deviation of the bus lateral position (SDLP) were calculated during the simulated driving task. Descriptive statistics and the Spearman correlation coefficient were used to describe and analyze the data. Fatigue levels had an increasing trend as the time-on-task of driving increased. Time-on-task of driving had the greatest effect on the fatigue self-evaluation (r = 0.605, p < 0.0001). The results showed a significant correlation between fatigue self-evaluation and bus lateral position (r = 0.567, p < 0.0001). As the time of driving increased, driving performance was affected adversely, as shown by the increase in the SDLP. Even so, the effect of individual differences on driving performance should not be overlooked. This work concludes that predicting the state of a driver fatigue based on the group mean data has some complications for any application.

Correlation between Driver Subjective Fatigue and Bus Lateral Position in a Driving Simulator

PubMed Central

Gharagozlou, Faramarz; Mazloumi, Adel; Saraji, Gebraeil Nasl; Nahvi, Ali; Ashouri, Mohammadreza; Mozaffari, Hamed

2015-01-01

Background: Driver fatigue as a leading cause of death in the transportation industry can impair the driving performance in long-distance driving task. Studies on the links of driver subjective fatigue and the bus lateral position are still an exploratory issue that requires further investigation. This study aimed to determine the correlation between the driver subjective fatigue and the bus lateral position in a driving simulator. Methods: This descriptive-analytical research was conducted on 30 professional male bus drivers participated in a two-hour driving session. The driver subjective fatigue was assessed by the Fatigue Visual Analogue Scale (F-VAS) at 10-min intervals. Simultaneously, the performance measures of lane drifting as the mean and standard deviation of the bus lateral position (SDLP) were calculated during the simulated driving task. Descriptive statistics and the Spearman correlation coefficient were used to describe and analyze the data. Results: Fatigue levels had an increasing trend as the time-on-task of driving increased. Time-on-task of driving had the greatest effect on the fatigue self-evaluation (r = 0.605, p < 0.0001). The results showed a significant correlation between fatigue self-evaluation and bus lateral position (r = 0.567, p < 0.0001). Conclusion: As the time of driving increased, driving performance was affected adversely, as shown by the increase in the SDLP. Even so, the effect of individual differences on driving performance should not be overlooked. This work concludes that predicting the state of a driver fatigue based on the group mean data has some complications for any application. PMID:26396734

Otolith shape lends support to the sensory drive hypothesis in rockfishes.

PubMed

Tuset, V M; Otero-Ferrer, J L; Gómez-Zurita, J; Venerus, L A; Stransky, C; Imondi, R; Orlov, A M; Ye, Z; Santschi, L; Afanasiev, P K; Zhuang, L; Farré, M; Love, M S; Lombarte, A

2016-10-01

The sensory drive hypothesis proposes that environmental factors affect both signalling dynamics and the evolution of signals and receivers. Sound detection and equilibrium in marine fishes are senses dependent on the sagittae otoliths, whose morphological variability appears intrinsically linked to the environment. The aim of this study was to understand if and which environmental factors could be conditioning the evolution of this sensory structure, therefore lending support to the sensory drive hypothesis. Thus, we analysed the otolith shape of 42 rockfish species (Sebastes spp.) to test the potential associations with the phylogeny, biological (age), ecological (feeding habit and depth distribution) and biogeographical factors. The results showed strong differences in the otolith shapes of some species, noticeably influenced by ecological and biogeographical factors. Moreover, otolith shape was clearly conditioned by phylogeny, but with a strong environmental effect, cautioning about the use of this structure for the systematics of rockfishes or other marine fishes. However, our most relevant finding is that the data supported the sensory drive hypothesis as a force promoting the radiation of the genus Sebastes. This hypothesis holds that adaptive divergence in communication has significant influence relative to other life history traits. It has already been established in Sebastes for visual characters and organs; our results showed that it applies to otolith transformations as well (despite the clear influence of feeding and depth), expanding the scope of the hypothesis to other sensory structures. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

Estrous Cyclicity of Mice During Simulated Weightlessness

NASA Technical Reports Server (NTRS)

Moyer, Eric; Talyansky, Yuli; Scott, Ryan; Tash, Joseph; Christenson, Lane; Alwood, Joshua; Ronca, April

2017-01-01

Hindlimb unloading (HU) is a rodent model system used to simulate weightlessness experienced in space. However, some effects of this approach on rodent physiology are under-studied, specifically the effects on ovarian estrogen production which drives the estrous cycle. To resolve this deficiency, we conducted a ground-based validation study using the HU model, while monitoring estrous cycles in 16-weeks-old female C57BL6 mice. Animals were exposed to HU for 12 days following a 3 day HU cage acclimation period, and estrous cycling was analyzed in HU animals (n22), normally loaded HU Cage Pair-Fed controls (CPF; n22), and Vivarium controls fed ad libitum (VIV; n10). Pair feeding was used to control for potential nutritional deficits on ovarian function. Vaginal cells were sampled daily in all mice via saline lavage. Cells were dried and stained with crystal violet, and the smears evaluated using established vaginal cytology techniques by two individuals blinded to the animal treatment group. Estrous cyclicity was disrupted in nearly all HU and CPF mice, while those maintained in VIV had an average normal cycle length of 4.8 0.5 days, with all stages in the cycle visibly observed. CPF and HU animals arrested in the diestrous phase, which precedes the pre-ovulatory estrogen surge. Additionally, infection-like symptoms characterized by vaginal discharge and swelling arose in several HU animals, which we suspect was due to an inability of these mice to properly groom themselves, andor due to the change in the gravity vector relative to the vaginal opening, which prevented drainage of the lavage solution. Pair-feeding resulted in similar weight gains of HU and CPF (1.5 vs 3.0, respectively). The current results indicate that pair-feeding controlled weight gain and that the HU cage alone influenced estrous cyclicity. Thus, longer acclimation needs to be tested to determine if and when normal estrous cycling resumes in non-loaded mice in HU cages prior to HU testing. Future studies might also examine whether modifications to the vaginal lavage procedure might prevent the onset of the infection-like symptoms, and allow estrous cyclicity to be measured in this model system.

Chasing the silver bullet: measuring driver fatigue using simple and complex tasks.

PubMed

Baulk, S D; Biggs, S N; Reid, K J; van den Heuvel, C J; Dawson, D

2008-01-01

Driver fatigue remains a significant cause of motor-vehicle accidents worldwide. New technologies are increasingly utilised to improve road safety, but there are no effective on-road measures for fatigue. While simulated driving tasks are sensitive, and simple performance tasks have been used in industrial fatigue management systems (FMS) to quantify risk, little is known about the relationship between such measures. Establishing a simple, on-road measure of fatigue, as a fitness-to-drive tool, is an important issue for road safety and accident prevention, particularly as many fatigue related accidents are preventable. This study aimed to measure fatigue-related performance decrements using a simple task (reaction time - RT) and a complex task (driving simulation), and to determine the potential for a link between such measures, thus improving FMS success. Fifteen volunteer participants (7 m, 8 f) aged 22-56 years (mean 33.6 years), underwent 26 h of supervised wakefulness before an 8h recovery sleep opportunity. Participants were tested using a 30-min interactive driving simulation test, bracketed by a 10-min psychomotor vigilance task (PVT) at 4, 8, 18 and 24h of wakefulness, and following recovery sleep. Extended wakefulness caused significant decrements in PVT and driving performance. Although these measures are clearly linked, our analyses suggest that driving simulation cannot be replaced by a simple PVT. Further research is needed to closely examine links between performance measures, and to facilitate accurate management of fitness to drive, which requires more complex assessments of performance than RT alone.

Modelling and Simulation in the Design Process of Armored Vehicles

DTIC Science & Technology

2003-03-01

trackway conditions is a demanding optimization task. Basically, a high level of ride comfort requires soft suspension tuning, whereas driving safety relies...The maximum off-road speed is generally limited by traction, input torque, driving safety and ride comfort. When obstacles are to be negotiated, the...wheel travel was defined during the mobility simulation runs. Figure 14: Ramp 1.5m at 40 kph; virtual and physical prototype Driving safety and ride

Distraction produces over-additive increases in the degree to which alcohol impairs driving performance.

PubMed

Van Dyke, Nicholas A; Fillmore, Mark T

2015-12-01

Research indicates that alcohol intoxication and increased demands on drivers' attention from distractions (e.g., passengers and cell phones) contribute to poor driving performance and increased rates of traffic accidents and fatalities. The present study examined the separate and combined effects of alcohol and distraction on simulated driving performance at blood alcohol concentrations (BrACs) below the legal driving limit in the USA (i.e., 0.08 %). Fifty healthy adult drivers (36 men and 14 women) were tested in a driving simulator following a 0.65-g/kg dose of alcohol and a placebo. Drivers completed two drive tests: a distracted drive, which included a two-choice detection task, and an undistracted control drive. Multiple indicators of driving performance, such as drive speed, within-lane deviation, steering rate, and lane exceedances were measured. Alcohol and distraction each impaired measures of driving performance. Moreover, the magnitude of alcohol impairment was increased by at least twofold when tested under the distracting versus the undistracted condition. The findings highlight the need for a clearer understanding of how common distractions impact intoxicated drivers, especially at BrACs that are currently legal for driving in the USA.

Separating Iso-Propanol-Toluene mixture by azeotropic distillation

NASA Astrophysics Data System (ADS)

Iqbal, Asma; Ahmad, Syed Akhlaq

2018-05-01

The separation of Iso-Propanol-Toluene azeotropic mixture using Acetone as an entrainer has been simulated on Aspen Plus software package using rigorous methods. Calculations of the vapor-liquid equilibrium for the binary system are done using UNIQUAC-RK model which gives a good agreement with the experimental data reported in literature. The effects of the Reflux ratio (RR), distillate-to-feed molar ratio (D/F), feed stage, solvent feed stage, Total no. of stages and solvent feed temperature on the product purities and recoveries are studied to obtain their optimum values that give the maximum purity and recovery of products. The configuration consists of 20 theoretical stages with an equimolar feed of binary mixture. The desired separation of binary mixture has been achieved at the feed stage and an entrainer feeding stage of 15 and 12 respectively with the reflux ratios of 2.5 and 4.0, and D/F ratio of 0.75 and 0.54 respectively in the two columns. The simulation results thus obtained are useful to setup the optimal column configuration of the azeotropic distillation process.

Automated Driving System Architecture to Ensure Safe Delegation of Driving Authority

NASA Astrophysics Data System (ADS)

YUN, Sunkil; NISHIMURA, Hidekazu

2016-09-01

In this paper, the architecture of an automated driving system (ADS) is proposed to ensure safe delegation of driving authority between the ADS and a driver. Limitations of the ADS functions may activate delegation of driving authority to a driver. However, it leads to severe consequences in emergency situations where a driver may be drowsy or distracted. To address these issues, first, the concept model for the ADS in the situation for delegation of driving authority is described taking the driver's behaviour and state into account. Second, the behaviour / state of a driver and functional flow / state of ADS and the interactions between them are modelled to understand the context where the ADS requests to delegate the driving authority to a driver. Finally, the proposed architecture of the ADS is verified under the simulations based on the emergency braking scenarios. In the verification process using simulation, we have derived the necessary condition for safe delegation of driving authority is that the ADS should assist s driver even after delegating driving authority to a driver who has not enough capability to regain control of the driving task.

Seasonal foraging responses of beavers to sodium-enhanced foods: An experimental assessment with field feeding trials

USGS Publications Warehouse

Strules, Jennifer; DeStefano, Stephen

2015-01-01

Salt drive is a seasonal phenomenon common to several classes of wild herbivores. Coincident with shifts of nutrient quality when plants resume growth in the spring, sodium is secondarily lost as surplus potassium is excreted. The beaver (Castor canadensis) is an herbivore whose dietary niche closely follows that of other herbivores that are subject to salt drive, but no published studies to date have assessed the likelihood of its occurrence. To quantify if beavers experience seasonal salt drive, we designed a field experiment to measure the foraging responses of beavers to sodium-enhanced foods. We used sodium-treated (salted) and control (no salt) food items (aspen [Populus tremuloides] and pine [Pinus spp.] sticks) during monthly feeding trials at beaver-occupied wetlands. If conventional ontogeny of salt drive was operant, we expected to observe greater utility of sodium-treated food items by beavers in May and June. Further, if water lilies (Nymphaea spp. and Nuphar spp.) supply beavers with sodium to meet dietary requirements as is widely speculated, we expected foraging responses to sodium-treated food items at wetlands where water lilies were absent to be greater than at wetlands where water lily was present. Aspen was selected by beavers in significantly greater amounts than pine. There was no difference between the mean percent consumed of salted and control aspen sticks by beavers at lily and non-lily wetlands, and no differences in temporal consumption associated with salted or control pine sticks at either wetland type. Salted pine was consumed in greater amounts than unsalted pine. We propose that the gastrointestinal or renal physiology of beavers may preclude solute loss, thereby preventing salt drive.

Feeding of swimming Paramecium with fore-aft asymmetry in viscous fluid

NASA Astrophysics Data System (ADS)

Zhang, Peng; Jana, Saikat; Giarra, Matthew; Vlachos, Pavlos; Jung, Sunghwan

2013-11-01

Swimming behaviours and feeding efficiencies of Paramecium Multimicronucleatum with fore-aft asymmetric body shapes are studied experimentally and numerically. Among various possible swimming ways, ciliates typically exhibit only one preferred swimming directions in favorable conditions. Ciliates, like Paramecia, with fore-aft asymmetric shapes preferably swim towards the slender anterior while feeding fluid to the oral groove located at the center of the body. Since both feeding and swimming efficiencies are influenced by fluid motions around the body, it is important to reveal the fluid mechanics around a moving object. Experimentally, μ-PIV methods are employed to characterize the source-dipole streamline patterns and fluid motions around Paramecium. Numerical simulations by boundary element methods are also used to evaluate surface stresses and velocities, which give insights into the efficiencies of swimming and feeding depending on body asymmetry. It is concluded that a slender anterior and fat posterior increases the combined efficiency of swimming and feeding, which matches well with actual shapes of Paramecium. Discrepancies between experiments and simulations are also discussed.

Design and evaluation of a Stochastic Optimal Feed-forward and Feedback Technology (SOFFT) flight control architecture

NASA Technical Reports Server (NTRS)

Ostroff, Aaron J.; Proffitt, Melissa S.

1994-01-01

This paper describes the design and evaluation of a stochastic optimal feed-forward and feedback technology (SOFFT) control architecture with emphasis on the feed-forward controller design. The SOFFT approach allows the designer to independently design the feed-forward and feedback controllers to meet separate objectives and then integrate the two controllers. The feed-forward controller has been integrated with an existing high-angle-of-attack (high-alpha) feedback controller. The feed-forward controller includes a variable command model with parameters selected to satisfy level 1 flying qualities with a high-alpha adjustment to achieve desired agility guidelines, a nonlinear interpolation approach that scales entire matrices for approximation of the plant model, and equations for calculating feed-forward gains developed for perfect plant-model tracking. The SOFFT design was applied to a nonlinear batch simulation model of an F/A-18 aircraft modified for thrust vectoring. Simulation results show that agility guidelines are met and that the SOFFT controller filters undesired pilot-induced frequencies more effectively during a tracking task than a flight controller that has the same feedback control law but does not have the SOFFT feed-forward control.

Evaluation of blue light exposure to beta brainwaves on simulated night driving

NASA Astrophysics Data System (ADS)

Purawijaya, Dandri Aly; Fitri, Lulu Lusianti; Suprijanto

2015-09-01

Numbers of night driving accident in Indonesia since 2010 are exponentially rising each year with total of loss more than 50 billion rupiah. One of the causes that contribute to night driving accident is drowsiness. Drowsiness is affected by circadian rhythm resulted from the difference of blue light quality and quantity between night and day. Blue light may effect on human physiology through non-visual pathway by suppressing melatonin hormone suppression that influence drowsiness. Meanwhile, the production of hormones and other activities in brain generate bioelectrical activity such as brainwaves and can be recorded using Electroencephalograph (EEG). Therefore, this research objective is to evaluate the effect of blue light exposure to beta brainwave emergence during night driving simulation to a driver. This research was conducted to 4 male subjects who are able to drive and have a legitimate car driving license. The driving simulator was done using SCANIA Truck Driving Simulator on freeform driving mode in dark environment. Subjects drove for total 32 minutes. The data collections were taken in 2 days with 16 minutes for each day. The 16 minutes were divided again into 8 minutes adaptation in dark and 8 minutes for driving either in blue light exposure or in total darkness. While driving the simulation, subjects' brainwaves were recorded using EEG EMOTIV 14 Channels, exposed by LED monochromatic blue light with 160 Lux from source and angle 45o and sat 1 m in front of the screen. Channels used on this research were for visual (O1; O2), cognition (F3; F4; P7; P8), and motor (FC5; FC6). EEG brainwave result was filtered with EEGLab to obtain beta waves at 13 - 30 Hz frequencies. Results showed that beta waves response to blue light varied for each subject. Blue light exposure either increased or decreased beta waves in 2 minutes pattern and maintaining beta waves on cognition and motor area in 3 out of 4 subjects. Meanwhile, blue light exposure did not maintain and induce beta waves fluctuation on visual area of another 2 subjects. The conclusion of this research is that blue light exposure affected the pattern of beta waves on frontal, parietal, premotor cortex and visual lobes.

Sleep inertia associated with a 10-min nap before the commute home following a night shift: A laboratory simulation study.

PubMed

Hilditch, Cassie J; Dorrian, Jillian; Centofanti, Stephanie A; Van Dongen, Hans P; Banks, Siobhan

2017-02-01

Night shift workers are at risk of road accidents due to sleepiness on the commute home. A brief nap at the end of the night shift, before the commute, may serve as a sleepiness countermeasure. However, there is potential for sleep inertia, i.e. transient impairment immediately after awakening from the nap. We investigated whether sleep inertia diminishes the effectiveness of napping as a sleepiness countermeasure before a simulated commute after a simulated night shift. N=21 healthy subjects (aged 21-35 y; 12 females) participated in a 3-day laboratory study. After a baseline night, subjects were kept awake for 27h for a simulated night shift. They were randomised to either receive a 10-min nap ending at 04:00 plus a 10-min pre-drive nap ending at 07:10 (10-NAP) or total sleep deprivation (NO-NAP). A 40-min York highway driving task was performed at 07:15 to simulate the commute. A 3-min psychomotor vigilance test (PVT-B) and the Samn-Perelli Fatigue Scale (SP-Fatigue) were administered at 06:30 (pre-nap), 07:12 (post-nap), and 07:55 (post-drive). In the 10-NAP condition, total pre-drive nap sleep time was 9.1±1.2min (mean±SD), with 1.3±1.9min spent in slow wave sleep, as determined polysomnographically. There was no difference between conditions in PVT-B performance at 06:30 (before the nap). In the 10-NAP condition, PVT-B performance was worse after the nap (07:12) compared to before the nap (06:30); no change across time was found in the NO-NAP condition. There was no significant difference between conditions in PVT-B performance after the drive. SP-Fatigue and driving performance did not differ significantly between conditions. In conclusion, the pre-drive nap showed objective, but not subjective, evidence of sleep inertia immediately after awakening. The 10-min nap did not affect driving performance during the simulated commute home, and was not effective as a sleepiness countermeasure. Copyright © 2015 Elsevier Ltd. All rights reserved.

Driving simulator scenarios and measures to faithfully evaluate risky driving behavior: A comparative study of different driver age groups

PubMed Central

Chaumillon, Romain; Nguyen-Tri, David; Watanabe, Donald; Hirsch, Pierro; Bellavance, Francois; Giraudet, Guillaume; Bernardin, Delphine; Faubert, Jocelyn

2017-01-01

To investigate the links between mental workload, age and risky driving, a cross-sectional study was conducted on a driving simulator using several established and some novel measures of driving ability and scenarios of varying complexity. A sample of 115 drivers was divided into three age and experience groups: young inexperienced (18–21 years old), adult experienced (25–55 years old) and older adult (70–86 years old). Participants were tested on three different scenarios varying in mental workload from low to high. Additionally, to gain a better understanding of individuals’ ability to capture and integrate relevant information in a highly complex visual environment, the participants’ perceptual-cognitive capacity was evaluated using 3-dimensional multiple object tracking (3D-MOT). Results indicate moderate scenario complexity as the best suited to highlight well-documented differences in driving ability between age groups and to elicit naturalistic driving behavior. Furthermore, several of the novel driving measures were shown to provide useful, non-redundant information about driving behavior, complementing more established measures. Finally, 3D-MOT was demonstrated to be an effective predictor of elevated crash risk as well as decreased naturally-adopted mean driving speed, particularly among older adults. In sum, the present experiment demonstrates that in cases of either extreme high or low task demands, drivers can become overloaded or under aroused and thus task measures may lose sensitivity. Moreover, insights from the present study should inform methodological considerations for future driving simulator research. Importantly, future research should continue to investigate the predictive utility of perceptual-cognitive tests in the domain of driving risk assessment. PMID:29016693

K-T Transition into Chaos.

ERIC Educational Resources Information Center

McLean, Dewey M.

1988-01-01

Discusses the destabilizing influences that affect feedback systems in the earth and trigger disorganization. Presents information that integrates mantle degassing with feed-back systems, and the Sun-Earth-Space energy flow system which is the primary source of energy that drives the Earth's biosphere. (RT)

A comparison of the effect of mobile phone use and alcohol consumption on driving simulation performance.

PubMed

Leung, Sumie; Croft, Rodney J; Jackson, Melinda L; Howard, Mark E; McKenzie, Raymond J

2012-01-01

The present study compared the effects of a variety of mobile phone usage conditions to different levels of alcohol intoxication on simulated driving performance and psychomotor vigilance. Twelve healthy volunteers participated in a crossover design in which each participant completed a simulated driving task on 2 days, separated by a 1-week washout period. On the mobile phone day, participants performed the simulated driving task under each of 4 conditions: no phone usage, a hands-free naturalistic conversation, a hands-free cognitively demanding conversation, and texting. On the alcohol day, participants performed the simulated driving task at four different blood alcohol concentration (BAC) levels: 0.00, 0.04, 0.07, and 0.10. Driving performance was assessed by variables including time within target speed range, time spent speeding, braking reaction time, speed deviation, and lateral lane position deviation. In the BAC 0.07 and 0.10 alcohol conditions, participants spent less time in the target speed range and more time speeding and took longer to brake in the BAC 0.04, 0.07, and 0.10 than in the BAC 0.00 condition. In the mobile phone condition, participants took longer to brake in the natural hands-free conversation, cognitively demanding hands-free conversation and texting conditions and spent less time in the target speed range and more time speeding in the cognitively demanding, hands-free conversation, and texting conditions. When comparing the 2 conditions, the naturalistic conversation was comparable to the legally permissible BAC level (0.04), and the cognitively demanding and texting conversations were similar to the BAC 0.07 to 0.10 results. The findings of the current laboratory study suggest that very simple conversations on a mobile phone may not represent a significant driving risk (compared to legally permissible BAC levels), whereas cognitively demanding, hands-free conversation, and particularly texting represent significant risks to driving.

Alcohol impairment of performance on steering and discrete tasks in a driving simulator

DOT National Transportation Integrated Search

1974-12-01

In this program a simplified laboratory simulator was developed to test two types of tasks used in driving on the open road: a continuous "steering task" to regulate against gust induced disturbances and an intermittent "discrete response task" requi...

The use of a driving simulator to determine how time pressures impact driver aggressiveness.

DOT National Transportation Integrated Search

2017-06-01

Speeding greatly contributes to traffic safety with approximately a third of fatal crashes in the United States being speeding-related. Previous research has identified being late as a primary cause of speeding. In this driving simulator study, a vir...

Using driver simulators to measure the impact of distracted driving on commercial motor vehicle operators : [research brief].

DOT National Transportation Integrated Search

2015-06-01

This study addresses the impact of various distractions on commercial motor vehicle (CMV) operators. Using state-of-the-art driving simulators in realistic traffic, this project focused on CMV operator performance as drivers experienced distractions ...

Acute effects of alcohol on inhibitory control and simulated driving in DUI offenders.

PubMed

Van Dyke, Nicholas; Fillmore, Mark T

2014-06-01

The public health costs associated with alcohol-related traffic accidents have prompted considerable research aimed at identifying characteristics of individuals who drive under the influence (DUI) in order to improve treatment and prevention strategies. Survey studies consistently show that DUI offenders self-report higher levels of impulsivity compared to their nonoffending counterparts. However, little is known about how individuals with a DUI history respond under alcohol. Inhibitory control is a behavioral component of impulsivity thought to underlie risky drinking and driving behaviors. The present study examined the degree to which DUI drivers display deficits of inhibitory control in response to alcohol and the degree to which alcohol impaired their simulated driving performance. It was hypothesized that DUI offenders would display an increased sensitivity to the acute impairing effects of alcohol on simulated driving performance. Young adult drivers with a history of DUI and a demographically-comparable group of drivers with no history of DUI (controls) were tested following a 0.65 g/kg dose of alcohol and a placebo. Inhibitory control was measured by using a cued go/no-go task. Drivers then completed a driving simulation task that yielded multiple indicators of driving performance, such as within-lane deviation, steering rate, centerline crossings and road edge excursions, and drive speed. Results showed that although DUI offenders self-reported greater levels of impulsivity than did controls, no group differences were observed in the degree to which alcohol impaired inhibitory control and driving performance. The findings point to the need to identify other aspects of behavioral dysfunction underlying the self-reported impulsivity among DUI offenders, and to better understand the specific driving situations that might pose greater risk to DUI offenders. The systematic study of candidate cognitive deficits in DUI offenders will provide important information on their role in risky driving behavior and decisions to drink and drive. Such information is critical for guiding new interventions for DUI offenders that will move treatment beyond general addiction counseling. Copyright © 2014 Elsevier B.V. All rights reserved.

Numerical simulation and optimization of red mud separation thickener with self-dilute feed

DOE PAGES

Zhou, Tian; Li, Mao; Zhou, Chenn-qian; ...

2014-03-01

In order to acquire the flow pattern and investigate the settling behavior of the red mud in the separation thickener, computational fluid dynamics (CFD), custom subroutines and agglomerates settling theory were employed to simulate the three-dimensional flow field in an industrial scale thickener with the introduction of a self-dilute feed system. Our simulation results show good agreement with the measurement onsite and the flow patterns of the thickener are presented and discussed on both velocity and concentration field. Optimization experiments on feed well and self-dilute system were also carried out, and indicate that the optimal thickener system can dilute themore » solid concentration in feed well from 110 g/L to 86 g/L which would help the agglomerates’ formation and improve the red mud settling speed. The additional power of recirculation pump can be saved and flocculants dosage was reduced from 105g/t to 85g/t in the operation.« less

An excitatory paraventricular nucleus to AgRP neuron circuit that drives hunger.

PubMed

Krashes, Michael J; Shah, Bhavik P; Madara, Joseph C; Olson, David P; Strochlic, David E; Garfield, Alastair S; Vong, Linh; Pei, Hongjuan; Watabe-Uchida, Mitsuko; Uchida, Naoshige; Liberles, Stephen D; Lowell, Bradford B

2014-03-13

Hunger is a hard-wired motivational state essential for survival. Agouti-related peptide (AgRP)-expressing neurons in the arcuate nucleus (ARC) at the base of the hypothalamus are crucial to the control of hunger. They are activated by caloric deficiency and, when naturally or artificially stimulated, they potently induce intense hunger and subsequent food intake. Consistent with their obligatory role in regulating appetite, genetic ablation or chemogenetic inhibition of AgRP neurons decreases feeding. Excitatory input to AgRP neurons is important in caloric-deficiency-induced activation, and is notable for its remarkable degree of caloric-state-dependent synaptic plasticity. Despite the important role of excitatory input, its source(s) has been unknown. Here, through the use of Cre-recombinase-enabled, cell-specific neuron mapping techniques in mice, we have discovered strong excitatory drive that, unexpectedly, emanates from the hypothalamic paraventricular nucleus, specifically from subsets of neurons expressing thyrotropin-releasing hormone (TRH) and pituitary adenylate cyclase-activating polypeptide (PACAP, also known as ADCYAP1). Chemogenetic stimulation of these afferent neurons in sated mice markedly activates AgRP neurons and induces intense feeding. Conversely, acute inhibition in mice with caloric-deficiency-induced hunger decreases feeding. Discovery of these afferent neurons capable of triggering hunger advances understanding of how this intense motivational state is regulated.

System for throttling and compensation for variable feedstock properties

DOEpatents

Meyer, J. W.

1981-05-05

Apparatus is shown for adjusting the feed rate of pulverized feed material into a pressurized container. The apparatus also has utility for compensating for variations in the permeability of the feed material. A rotor that includes sprues with provision for controlling the pressure distribution along the sprues is located within the pressurized container. The rotor hub is connected to a drive means and a material supply means which extend through the wall of the container. A line for controlling pressure along the sprues by gas injection is connected to a chamber between sections of the sprue for controlling gas pressure at that point. The gas pressure control line is connected to a pressurized gas source and a control system external to the rotor. 10 figs.

System for throttling and compensation for variable feedstock properties

DOEpatents

Meyer, John W.

1981-01-01

Apparatus is shown for adjusting the feed rate of pulverized feed material into a pressurized container. The apparatus also has utility for compensating for variations in the permeability of the feed material. A rotor that includes sprues with provision for controlling the pressure distribution along the sprues is located within the pressurized container. The rotor hub is connected to a drive means and a material supply means which extend through the wall of the container. A line for controlling pressure along the sprues by gas injection is connected to a chamber between sections of the sprue for controlling gas pressure at that point. The gas pressure control line is connected to a pressurized gas source and a control system external to the rotor.

Driving the need to feed: Insight into the collaborative interaction between ghrelin and endocannabinoid systems in modulating brain reward systems.

PubMed

Edwards, Alexander; Abizaid, Alfonso

2016-07-01

Independent stimulation of either the ghrelin or endocannabinoid system promotes food intake and increases adiposity. Given the similar distribution of their receptors in feeding associated brain regions and organs involved in metabolism, it is not surprising that evidence of their interaction and its importance in modulating energy balance has emerged. This review documents the relationship between ghrelin and endocannabinoid systems within the periphery and hypothalamus (HYP) before presenting evidence suggesting that these two systems likewise work collaboratively within the ventral tegmental area (VTA) to modulate non-homeostatic feeding. Mechanisms, consistent with current evidence and local infrastructure within the VTA, will be proposed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Commercial Truck Driver Health and Safety: Exploring Distracted Driving Performance and Self-Reported Driving Skill.

PubMed

Stavrinos, Despina; Heaton, Karen; Welburn, Sharon C; McManus, Benjamin; Griffin, Russell; Fine, Philip R

2016-08-01

Reducing distracters detrimental to commercial truck driving is a critical component of improving the safety performance of commercial drivers, and makes the highways safer for all drivers. This study used a driving simulator to examine effects of cell phone, texting, and email distractions as well as self-reported driver optimism bias on the driving performance of commercial truck drivers. Results revealed that more visually demanding tasks were related to poorer driving performance. However, the cell phone task resulted in less off-the-road eye glances. Drivers reporting being "very skilled" displayed poorer driving performance than those reporting being "skilled." Onboard communication devices provide a practical, yet visually and manually demanding, solution for connecting drivers and dispatchers. Trucking company policies should minimize interaction between dispatchers and drivers when the truck is in motion. Training facilities should integrate driving simulators into the instruction of commercial drivers, targeting over-confident drivers. © 2016 The Author(s).

Objective assessment of the effects of texting while driving: a simulator study.

PubMed

Bendak, Salaheddine

2015-01-01

Recent advances in electronic communication technology led to many drivers opting to send and receive text messages while driving. This, inevitably, has a potential to distract drivers, impair driving performance and lead to crashes. This study aims to assess the risk involved in texting while driving through assessing the distraction caused and determining the change in key driving performance indicators. Twenty-one paid young male volunteers were recruited to participate in this study. Each participant drove a driving simulator on four different scenarios involving driving while texting and without texting on highways and town roads. Results showed that texting while driving led, on average, to five times more crashes than driving without texting. Due to distraction also, participants unnecessarily crossed lane boundaries and road boundaries more often while texting as compared to driving without texting. Moreover, distraction due to texting led to participants deviating their eyes off the road while texting 15 times per session, on average, more than without texting. Results demonstrated a high-risk level of distraction and clear impairment in drivers' ability to drive safely due to texting. Based on the results, practical recommendations to combat this phenomenon are given.

Electrohydraulic linear actuator with two stepping motors controlled by overshoot-free algorithm

NASA Astrophysics Data System (ADS)

Milecki, Andrzej; Ortmann, Jarosław

2017-11-01

The paper describes electrohydraulic spool valves with stepping motors used as electromechanical transducers. A new concept of a proportional valve in which two stepping motors are working differentially is introduced. Such valve changes the fluid flow proportionally to the sum or difference of the motors' steps numbers. The valve design and principle of its operation is described. Theoretical equations and simulation models are proposed for all elements of the drive, i.e., the stepping motor units, hydraulic valve and cylinder. The main features of the valve and drive operation are described; some specific problem areas covering the nature of stepping motors and their differential work in the valve are also considered. The whole servo drive non-linear model is proposed and used further for simulation investigations. The initial simulation investigations of the drive with a new valve have shown that there is a significant overshoot in the drive step response, which is not allowed in positioning process. Therefore additional effort is spent to reduce the overshoot and in consequence reduce the settling time. A special predictive algorithm is proposed to this end. Then the proposed control method is tested and further improved in simulations. Further on, the model is implemented in reality and the whole servo drive system is tested. The investigation results presented in this paper, are showing an overshoot-free positioning process which enables high positioning accuracy.

'I didn't see that coming': simulated visual fields and driving hazard perception test performance.

PubMed

Glen, Fiona C; Smith, Nicholas D; Jones, Lee; Crabb, David P

2016-09-01

Evidence is limited regarding specific types of visual field loss associated with unsafe driving. We use novel gaze-contingent software to examine the effect of simulated visual field loss on computer-based driving hazard detection with the specific aim of testing the impact of scotomata located to the right and left of fixation. The 'hazard perception test' is a component of the UK driving licence examination, which measures speed of detecting 15 different hazards in a series of real-life driving films. We have developed a novel eye-tracking and computer set up capable of generating a realistic gaze-contingent scotoma simulation (GazeSS) overlaid on film content. Thirty drivers with healthy vision completed three versions of the hazard perception test in a repeated measures experiment. In two versions, GazeSS simulated a scotoma in the binocular field of view to the left or right of fixation. A third version was unmodified to establish baseline performance. Participants' mean baseline hazard perception test score was 51 ± 7 (out of 75). This reduced to 46 ± 9 and 46 ± 11 when completing the task with a binocular visual field defect located to the left and right of fixation, respectively. While the main effect of simulated visual field loss on performance was statistically significant (p = 0.007), there were no average differences in the experimental conditions where a scotoma was located in the binocular visual field to the right or left of fixation. Simulated visual field loss impairs driving hazard detection on a computer-based test. There was no statistically significant difference in average performance when the simulated scotoma was located to the right or left of fixation of the binocular visual field, but certain types of hazard caused more difficulties than others. © 2016 Optometry Australia.

Reactivity-controlled compression ignition drive cycle emissions and fuel economy estimations using vehicle system simulations

DOE PAGES

Curran, Scott J.; Gao, Zhiming; Wagner, Robert M.

2014-12-22

In-cylinder blending of gasoline and diesel to achieve reactivity-controlled compression ignition has been shown to reduce NO X and soot emissions while maintaining or improving brake thermal efficiency as compared with conventional diesel combustion. The reactivity-controlled compression ignition concept has an advantage over many advanced combustion strategies in that the fuel reactivity can be tailored to the engine speed and load, allowing stable low-temperature combustion to be extended over more of the light-duty drive cycle load range. In this paper, a multi-mode reactivity-controlled compression ignition strategy is employed where the engine switches from reactivity-controlled compression ignition to conventional diesel combustionmore » when speed and load demand are outside of the experimentally determined reactivity-controlled compression ignition range. The potential for reactivity-controlled compression ignition to reduce drive cycle fuel economy and emissions is not clearly understood and is explored here by simulating the fuel economy and emissions for a multi-mode reactivity-controlled compression ignition–enabled vehicle operating over a variety of US drive cycles using experimental engine maps for multi-mode reactivity-controlled compression ignition, conventional diesel combustion, and a 2009 port-fuel injected gasoline engine. Drive cycle simulations are completed assuming a conventional mid-size passenger vehicle with an automatic transmission. Multi-mode reactivity-controlled compression ignition fuel economy simulation results are compared with the same vehicle powered by a representative 2009 port-fuel injected gasoline engine over multiple drive cycles. Finally, engine-out drive cycle emissions are compared with conventional diesel combustion, and observations regarding relative gasoline and diesel tank sizes needed for the various drive cycles are also summarized.« less

Older Adults with Mild Cognitive Impairments Show Less Driving Errors after a Multiple Sessions Simulator Training Program but Do Not Exhibit Long Term Retention.

PubMed

Teasdale, Normand; Simoneau, Martin; Hudon, Lisa; Germain Robitaille, Mathieu; Moszkowicz, Thierry; Laurendeau, Denis; Bherer, Louis; Duchesne, Simon; Hudon, Carol

2016-01-01

The driving performance of individuals with mild cognitive impairment (MCI) is suboptimal when compared to healthy older adults. It is expected that the driving will worsen with the progression of the cognitive decline and thus, whether or not these individuals should continue to drive is a matter of debate. The aim of the study was to provide support to the claim that individuals with MCI can benefit from a training program and improve their overall driving performance in a driving simulator. Fifteen older drivers with MCI participated in five training sessions in a simulator (over a 21-day period) and in a 6-month recall session. During training, they received automated auditory feedback on their performance when an error was noted about various maneuvers known to be suboptimal in MCI individuals (for instance, weaving, omitting to indicate a lane change, to verify a blind spot, or to engage in a visual search before crossing an intersection). The number of errors was compiled for eight different maneuvers for all sessions. For the initial five sessions, a gradual and significant decrease in the number of errors was observed, indicating learning and safer driving. The level of performance, however, was not maintained at the 6-month recall session. Nevertheless, the initial learning observed opens up possibilities to undertake more regular interventions to maintain driving skills and safe driving in MCI individuals.

Evaluating and Enhancing Driving Ability Among Teens with Autism Spectrum Disorder (ASD)

DTIC Science & Technology

2014-10-01

impact. 15. SUBJECT TERMS Autism, Driving Safety , Driving Simulation, Automated Feedback, Eye Tracking 16. SECURITY CLASSIFICATION OF: 17...driving training (RT) required by the DMV, VRDS training + RT (VRDS-T) would lead to greater improvement in driving safety and less driving anxiety, 2...the Idea Development award we learned that VRDS-T can significantly improve the driving safety of novice drivers with ASD, and this is not enhanced by

Angular radiation temperature simulation for time-dependent capsule drive prediction in inertial confinement fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jing, Longfei; Yang, Dong; Li, Hang

2015-02-15

The x-ray drive on a capsule in an inertial confinement fusion setup is crucial for ignition. Unfortunately, a direct measurement has not been possible so far. We propose an angular radiation temperature simulation to predict the time-dependent drive on the capsule. A simple model, based on the view-factor method for the simulation of the radiation temperature, is presented and compared with the experimental data obtained using the OMEGA laser facility and the simulation results acquired with VISRAD code. We found a good agreement between the time-dependent measurements and the simulation results obtained using this model. The validated model was thenmore » used to analyze the experimental results from the Shenguang-III prototype laser facility. More specifically, the variations of the peak radiation temperatures at different view angles with the albedo of the hohlraum, the motion of the laser spots, the closure of the laser entrance holes, and the deviation of the laser power were investigated. Furthermore, the time-dependent radiation temperature at different orientations and the drive history on the capsule were calculated. The results indicate that the radiation temperature from “U20W112” (named according to the diagnostic hole ID on the target chamber) can be used to approximately predict the drive temperature on the capsule. In addition, the influence of the capsule on the peak radiation temperature is also presented.« less

Growing ethanol sector drives corn supply chain shift for the last decade

NASA Astrophysics Data System (ADS)

Kim, T.; Schmitt, J.; Brauman, K. A.; Smith, T. M.; Suh, K.

2017-12-01

The US is the largest producer in the world, 89% of corn production uses in domestic demands in 2012. Carbon emission and irrigated water usage in the corn farming stage are hot-spot in the meat production sectors, comprise 37% of all US corn demand. The annual capacity of the ethanol sector increases from 6.5 billion gallons to 15.3 billion gallons for the last decade. The growth of corn demand in ethanol sector makes corn supply chain shift. Most of the ethanol plants located in the Mid-west where is the top 12 corn producing states. Therefore animal feeds take more supply from the other states. The purpose of this study is to estimate environmental impacts and water scarcity associated embedded corn by the temporal and spatial corn supply chain model based on a cost minimization. We use publicly available county-level data on corn production, feed demands, aggregative carbon emission and irrigated water usage in farming state, and a water depletion index as a metric for determining water scarcity. The water stressed counties produce 23.3% of US total corn production in 2012, and the irrigated corn is 14.2%. We simulated the corn supply chain using linear programming and developed the web-based visualization tools called FoodS3 (Food Systems Supply-chain Sustainability tool, http://foods3.org).

Driving Performance Under Alcohol in Simulated Representative Driving Tasks

PubMed Central

Kenntner-Mabiala, Ramona; Kaussner, Yvonne; Jagiellowicz-Kaufmann, Monika; Hoffmann, Sonja; Krüger, Hans-Peter

2015-01-01

Abstract Comparing drug-induced driving impairments with the effects of benchmark blood alcohol concentrations (BACs) is an approved approach to determine the clinical relevance of findings for traffic safety. The present study aimed to collect alcohol calibration data to validate findings of clinical trials that were derived from a representative test course in a dynamic driving simulator. The driving performance of 24 healthy volunteers under placebo and with 0.05% and 0.08% BACs was measured in a double-blind, randomized, crossover design. Trained investigators assessed the subjects’ driving performance and registered their driving errors. Various driving parameters that were recorded during the simulation were also analyzed. Generally, the participants performed worse on the test course (P < 0.05 for the investigators’ assessment) under the influence of alcohol. Consistent with the relevant literature, lane-keeping performance parameters were sensitive to the investigated BACs. There were significant differences between the alcohol and placebo conditions in most of the parameters analyzed. However, the total number of errors was the only parameter discriminating significantly between all three BAC conditions. In conclusion, data show that the present experimental setup is suitable for future psychopharmacological research. Thereby, for each drug to be investigated, we recommend to assess a profile of various parameters that address different levels of driving. On the basis of this performance profile, the total number of driving errors is recommended as the primary endpoint. However, this overall endpoint should be completed by a specifically sensitive parameter that is chosen depending on the effect known to be induced by the tested drug. PMID:25689289

Peer passenger influences on male adolescent drivers’ visual scanning behavior during simulated driving

PubMed Central

Pradhan, Anuj K.; Li, Kaigang; Bingham, C. Raymond; Simons-Morton, Bruce; Ouimet, Marie Claude; Shope, Jean T.

2014-01-01

Purpose There is a higher likelihood of crashes and fatalities when an adolescent drives with peer passengers, especially for male drivers and male passengers. Simulated driving of male adolescent drivers with male peer passengers was studied to examine passenger influences on distraction and inattention. Methods Male adolescents drove in a high-fidelity driving simulator with a male confederate who posed either as a risk-accepting or risk-averse passenger. Drivers’ eye-movements were recorded. The visual scanning behavior of the drivers was compared when driving alone versus when driving with a passenger, and when driving with a risk-accepting versus a risk-averse passenger. Results The visual scanning of a driver significantly narrowed horizontally and vertically when driving with a peer passenger. There were no significant differences in the times the drivers’ eyes were off the forward roadway when driving with a passenger versus when driving alone. Some significant correlations were found between personality characteristics and the outcome measures. Conclusions The presence of a male peer passenger was associated with a reduction in the visual scanning range of male adolescent drivers. This reduction could be a result of potential cognitive load imposed on the driver due to the presence of a passenger and the real or perceived normative influences or expectations from the passenger. Implications and contribution The presence of male peer passengers was associated with deficient visual scanning in male adolescent drivers. Such reduced scanning behavior is evident in drivers with high cognitive load. Further investigation of passenger influences on adolescent drivers should include examination of distraction and inattention aspects of passenger influence. PMID:24759440

Cerebral oscillatory activity during simulated driving using MEG

PubMed Central

Sakihara, Kotoe; Hirata, Masayuki; Ebe, Kazutoshi; Kimura, Kenji; Yi Ryu, Seong; Kono, Yoshiyuki; Muto, Nozomi; Yoshioka, Masako; Yoshimine, Toshiki; Yorifuji, Shiro

2014-01-01

We aimed to examine cerebral oscillatory differences associated with psychological processes during simulated car driving. We recorded neuromagnetic signals in 14 healthy volunteers using magnetoencephalography (MEG) during simulated driving. MEG data were analyzed using synthetic aperture magnetometry to detect the spatial distribution of cerebral oscillations. Group effects between subjects were analyzed statistically using a non-parametric permutation test. Oscillatory differences were calculated by comparison between “passive viewing” and “active driving.” “Passive viewing” was the baseline, and oscillatory differences during “active driving” showed an increase or decrease in comparison with a baseline. Power increase in the theta band was detected in the superior frontal gyrus (SFG) during active driving. Power decreases in the alpha, beta, and low gamma bands were detected in the right inferior parietal lobe (IPL), left postcentral gyrus (PoCG), middle temporal gyrus (MTG), and posterior cingulate gyrus (PCiG) during active driving. Power increase in the theta band in the SFG may play a role in attention. Power decrease in the right IPL may reflect selectively divided attention and visuospatial processing, whereas that in the left PoCG reflects sensorimotor activation related to driving manipulation. Power decreases in the MTG and PCiG may be associated with object recognition. PMID:25566017

Biological rhythms: the taste-time continuum.

PubMed

Krupp, Joshua J; Levine, Joel D

2010-02-23

The gustatory system allows the fly to assess food quality, eliciting either acceptance or avoidance behaviors. A new study demonstrates that circadian clocks in gustatory receptor neurons regulate rhythms in taste sensitivity, drive rhythms in appetitive behavior and influence feeding. Copyright 2010 Elsevier Ltd. All rights reserved.

Help NCI at Frederick “Knock Out Hunger” | Poster

Cancer.gov

NCI at Frederick is once again participating in the Feds Feed Families initiative, an annual food drive that addresses severe shortages of non-perishable items in food banks across D.C., Maryland, and Virginia during the summer months, when giving is at its lowest.

Hunger and Satiety Signaling: Modeling Two Hypothalamomedullary Pathways for Energy Homeostasis.

PubMed

Nakamura, Kazuhiro; Nakamura, Yoshiko

2018-06-04

The recent discovery of the medullary circuit driving "hunger responses" - reduced thermogenesis and promoted feeding - has greatly expanded our knowledge on the central neural networks for energy homeostasis. However, how hypothalamic hunger and satiety signals generated under fasted and fed conditions, respectively, control the medullary autonomic and somatic motor mechanisms remains unknown. Here, in reviewing this field, we propose two hypothalamomedullary neural pathways for hunger and satiety signaling. To trigger hunger signaling, neuropeptide Y activates a group of neurons in the paraventricular hypothalamic nucleus (PVH), which then stimulate an excitatory pathway to the medullary circuit to drive the hunger responses. In contrast, melanocortin-mediated satiety signaling activates a distinct group of PVH neurons, which then stimulate a putatively inhibitory pathway to the medullary circuit to counteract the hunger signaling. The medullary circuit likely contains inhibitory and excitatory premotor neurons whose alternate phasic activation generates the coordinated masticatory motor rhythms to promote feeding. © 2018 The Authors. BioEssays Published by WILEY Periodicals, Inc.

Emergence of gamma motor activity in an artificial neural network model of the corticospinal system.

PubMed

Grandjean, Bernard; Maier, Marc A

2017-02-01

Muscle spindle discharge during active movement is a function of mechanical and neural parameters. Muscle length changes (and their derivatives) represent its primary mechanical, fusimotor drive its neural component. However, neither the action nor the function of fusimotor and in particular of γ-drive, have been clearly established, since γ-motor activity during voluntary, non-locomotor movements remains largely unknown. Here, using a computational approach, we explored whether γ-drive emerges in an artificial neural network model of the corticospinal system linked to a biomechanical antagonist wrist simulator. The wrist simulator included length-sensitive and γ-drive-dependent type Ia and type II muscle spindle activity. Network activity and connectivity were derived by a gradient descent algorithm to generate reciprocal, known target α-motor unit activity during wrist flexion-extension (F/E) movements. Two tasks were simulated: an alternating F/E task and a slow F/E tracking task. Emergence of γ-motor activity in the alternating F/E network was a function of α-motor unit drive: if muscle afferent (together with supraspinal) input was required for driving α-motor units, then γ-drive emerged in the form of α-γ coactivation, as predicted by empirical studies. In the slow F/E tracking network, γ-drive emerged in the form of α-γ dissociation and provided critical, bidirectional muscle afferent activity to the cortical network, containing known bidirectional target units. The model thus demonstrates the complementary aspects of spindle output and hence γ-drive: i) muscle spindle activity as a driving force of α-motor unit activity, and ii) afferent activity providing continuous sensory information, both of which crucially depend on γ-drive.

Alcohol Dose Effects on Brain Circuits During Simulated Driving: An fMRI Study

PubMed Central

Meda, Shashwath A.; Calhoun, Vince D.; Astur, Robert S.; Turner, Beth M.; Ruopp, Kathryn; Pearlson, Godfrey D.

2009-01-01

Driving while intoxicated remains a major public health hazard. Driving is a complex task involving simultaneous recruitment of multiple cognitive functions. The investigators studied the neural substrates of driving and their response to different blood alcohol concentrations (BACs), using functional magnetic resonance imaging (fMRI) and a virtual reality driving simulator. We used independent component analysis (ICA) to isolate spatially independent and temporally correlated driving-related brain circuits in 40 healthy, adult moderate social drinkers. Each subject received three individualized, separate single-blind doses of beverage alcohol to produce BACs of 0.05% (moderate), 0.10% (high), or 0% (placebo). 3 T fMRI scanning and continuous behavioral measurement occurred during simulated driving. Brain function was assessed and compared using both ICA and a conventional general linear model (GLM) analysis. ICA results replicated and significantly extended our previous 1.5T study (Calhoun et al. [2004a]: Neuropsychopharmacology 29:2097–2017). GLM analysis revealed significant dose-related functional differences, complementing ICA data. Driving behaviors including opposite white line crossings and mean speed independently demonstrated significant dose-dependent changes. Behavior-based factors also predicted a frontal-basal-temporal circuit to be functionally impaired with alcohol dosage across baseline scaled, good versus poorly performing drivers. We report neural correlates of driving behavior and found dose-related spatio-temporal disruptions in critical driving-associated regions including the superior, middle and orbito frontal gyri, anterior cingulate, primary/supplementary motor areas, basal ganglia, and cerebellum. Overall, results suggest that alcohol (especially at high doses) causes significant impairment of both driving behavior and brain functionality related to motor planning and control, goal directedness, error monitoring, and memory. PMID:18571794

Astronaut John Young drives in One-G Lunar Roving Vehicle during simulation

NASA Image and Video Library

1971-03-04

Astronaut John W. Young, Apollo 16 prime crew commander (right), takes a drive in the One-G Lunar Roving Vehicle (LRV) trainer in the Lunar Topgraphic Simulation area at the Manned Spacecraft Center (MSC). He is accompanied by John Omstead, with General Electric, MSC.

A driving simulator study : evaluation of vehicle mounted attenuator markings in work zones during different times of the day.

DOT National Transportation Integrated Search

2010-09-01

This report presents a study of driver perceptions using a driving simulator carried out on the : effectiveness of four markings which vary in striping patterns and color combinations used at the : rear of vehicle mounted attenuators (VMAs) in work z...

Development of a personal computer-based secondary task procedure as a surrogate for a driving simulator

DOT National Transportation Integrated Search

2007-08-01

This research was conducted to develop and test a personal computer-based study procedure (PCSP) with secondary task loading for use in human factors laboratory experiments in lieu of a driving simulator to test reading time and understanding of traf...

ECO-DRIVING MODELING ENVIRONMENT

DOT National Transportation Integrated Search

2015-11-01

This research project aims to examine the eco-driving modeling capabilities of different traffic modeling tools available and to develop a driver-simulator-based eco-driving modeling tool to evaluate driver behavior and to reliably estimate or measur...

Sequential Dependencies in Driving

ERIC Educational Resources Information Center

Doshi, Anup; Tran, Cuong; Wilder, Matthew H.; Mozer, Michael C.; Trivedi, Mohan M.

2012-01-01

The effect of recent experience on current behavior has been studied extensively in simple laboratory tasks. We explore the nature of sequential effects in the more naturalistic setting of automobile driving. Driving is a safety-critical task in which delayed response times may have severe consequences. Using a realistic driving simulator, we find…

Predicting the impact of feed spacer modification on biofouling by hydraulic characterization and biofouling studies in membrane fouling simulators.

PubMed

Siddiqui, A; Lehmann, S; Bucs, Sz S; Fresquet, M; Fel, L; Prest, E I E C; Ogier, J; Schellenberg, C; van Loosdrecht, M C M; Kruithof, J C; Vrouwenvelder, J S

2017-03-01

Feed spacers are an essential part of spiral-wound reverse osmosis (RO) and nanofiltration (NF) membrane modules. Geometric modification of feed spacers is a potential option to reduce the impact of biofouling on the performance of membrane systems. The objective of this study was to evaluate the biofouling potential of two commercially available reference feed spacers and four modified feed spacers. The spacers were compared on hydraulic characterization and in biofouling studies with membrane fouling simulators (MFSs). The virgin feed spacer was characterized hydraulically by their resistance, measured in terms of feed channel pressure drop, performed by operating MFSs at varying feed water flow rates. Short-term (9 days) biofouling studies were carried out with nutrient dosage to the MFS feed water to accelerate the biofouling rate. Long-term (96 days) biofouling studies were done without nutrient dosage to the MFS feed water. Feed channel pressure drop was monitored and accumulation of active biomass was quantified by adenosine tri phosphate (ATP) determination. The six feed spacers were ranked on pressure drop (hydraulic characterization) and on biofouling impact (biofouling studies). Significantly different trends in hydraulic resistance and biofouling impact for the six feed spacers were observed. The same ranking for biofouling impact on the feed spacers was found for the (i) short-term biofouling study with nutrient dosage and the (ii) long-term biofouling study without nutrient dosage. The ranking for hydraulic resistance for six virgin feed spacers differed significantly from the ranking of the biofouling impact, indicating that hydraulic resistance of clean feed spacers does not predict the hydraulic resistance of biofouled feed spacers. Better geometric design of feed spacers can be a suitable approach to minimize impact of biofouling in spiral wound membrane systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

Distraction produces over-additive increases in the degree to which alcohol impairs driving performance

PubMed Central

Van Dyke, Nicholas A.; Fillmore, Mark T.

2015-01-01

Rationale Research indicates that alcohol intoxication and increased demands on drivers’ attention from distractions (e.g. passengers and cell phones) contribute to poor driving performance and increased rates of traffic accidents and fatalities. Objectives The present study examined the separate and combined effects of alcohol and distraction on simulated driving performance at blood alcohol concentrations (BrACs) below the legal driving limit in the United States (i.e. 0.08%). Methods Fifty healthy adult drivers (36 men and 14 women) were tested in a driving simulator following a 0.65 g/kg dose of alcohol and a placebo. Drivers completed two drive tests; a distracted drive, which included a two-choice detection task, and an undistracted control drive. Multiple indicators of driving performance, such as drive speed, within-lane deviation, steering rate, and lane exceedances were measured. Results Alcohol and distraction each impaired measures of driving performance. Moreover, the magnitude of alcohol impairment was increased by at least two-fold when tested under the distracting versus the undistracted condition. Conclusions The findings highlight the need for a clearer understanding of how common distractions impact intoxicated drivers, especially at BrACs that are currently legal for driving in the United States. PMID:26349918

Simulation of Trolleybus Traction Induction Drive With Supercapacitor Energy Storage System

NASA Astrophysics Data System (ADS)

Brazis, V.; Latkovskis, L.; Grigans, L.

2010-01-01

The article considers the possibilities of saving the regenerative braking energy in Škoda 24Tr type trolleybuses by installing the onboard supercapacitor energy storage system (ESS) and improving its performance with automated switching to the autonomous traction mode. Proposed is an ESS control system with constant DC bus voltage in the supercapacitor charging mode and supercapacitor current proportional to the AC drive current in the discharging mode. The authors investigate stability of the trolleybus ESS control system operating together with AC traction drive in various overhead voltage failure modes. The co-simulation of ESS operation was done by Matlab/Simulink AC drive and PSIM ESS continuous models.

Acceleration of planar foils by the indirect-direct drive scheme

NASA Astrophysics Data System (ADS)

Honrubia, J. J.; Martínez-Val, J. M.; Bocher, J. L.; Faucheux, G.

1996-05-01

We have investigated the hydrodynamic response of plastic and aluminum foils accelerated by a pulse formed by an x-ray prepulse followed by the main laser pulse. This illumination scheme, so-called indirect-direct drive scheme, has been proposed as an alternative to the direct and indirect drive. The advantages of such a scheme are that it can contribute to solve the problem of uniformity of the direct drive and, at the same time, it can be much more efficient and use simpler targets than the indirect-drive. Experiments about this hybrid drive scheme have been performed at Limeil with the PHEBUS facility and the standard experimental set-up and diagnostics. The agreement between experiments and simulations is good for quantities such as the energy of the laser converted into x-rays and the burnthrough time of the converter foil. To simulate the full hydrodynamic evolution of the converter and target foils separated a distance of 1 mm, 2-D effects should be taken into account. The basic goals have been to check the simulation codes developed by the Institute of Nuclear Fusion and to determine the hydrodynamic response of the target foil to the hybrid pulse. These goals have been fulfilled.

Modulation of appetite and feeding behavior of the larval mosquito Aedes aegypti by the serotonin-selective reuptake inhibitor paroxetine: shifts between distinct feeding modes and the influence of feeding status.

PubMed

Kinney, Michael P; Panting, Nicholas D; Clark, Thomas M

2014-03-15

The effects of the serotonin-selective reuptake inhibitor paroxetine (2×10(-5) mol l(-1)) on behavior of the larval mosquito Aedes aegypti are described. Four discrete behavioral states dominate larval behavior: wriggling, two distinct types of feeding, and quiescence. Feeding behaviors consist of foraging along the bottom of the container (substrate browsing), and stationary filter feeding while suspended from the surface film. Fed larvae respond to paroxetine with increased wriggling, and reductions in both feeding behaviors. In contrast, food-deprived larvae treated with paroxetine show no change in the proportion of time spent wriggling or feeding, but shift from stationary filter feeding to substrate browsing. Thus, actions of paroxetine in fed larvae are consistent with suppression of appetite and stimulation of wriggling, whereas paroxetine causes food-deprived larvae to switch from one feeding behavior to another. Further analysis of unfed larvae revealed that paroxetine decreased the power stroke frequency during wriggling locomotion, but had no effect on the swimming velocity during either wriggling or substrate browsing. These data suggest that: (1) serotonergic pathways may trigger shifts between distinct behaviors by actions on higher level (brain) integrating centers where behaviors such as feeding and locomotion are coordinated; (2) these centers in fed and food-deprived larvae respond differently to serotonergic stimulation suggesting sensory feedback from feeding status; and (3) serotonergic pathways also modulate central pattern generators of the nerve cord where the bursts of action potentials originate that drive the rhythmic muscle contractions of wriggling.

Solar and Heliospheric Observatory (SOHO) Flight Dynamics Simulations Using MATLAB (R)

NASA Technical Reports Server (NTRS)

Headrick, R. D.; Rowe, J. N.

1996-01-01

This paper describes a study to verify onboard attitude control laws in the coarse Sun-pointing (CSP) mode by simulation and to develop procedures for operational support for the Solar and Heliospheric Observatory (SOHO) mission. SOHO was launched on December 2, 1995, and the predictions of the simulation were verified with the flight data. This study used a commercial off the shelf product MATLAB(tm) to do the following: Develop procedures for computing the parasitic torques for orbital maneuvers; Simulate onboard attitude control of roll, pitch, and yaw during orbital maneuvers; Develop procedures for predicting firing time for both on- and off-modulated thrusters during orbital maneuvers; Investigate the use of feed forward or pre-bias torques to reduce the attitude handoff during orbit maneuvers - in particular, determine how to use the flight data to improve the feed forward torque estimates for use on future maneuvers. The study verified the stability of the attitude control during orbital maneuvers and the proposed use of feed forward torques to compensate for the attitude handoff. Comparison of the simulations with flight data showed: Parasitic torques provided a good estimate of the on- and off-modulation for attitude control; The feed forward torque compensation scheme worked well to reduce attitude handoff during the orbital maneuvers. The work has been extended to prototype calibration of thrusters from observed firing time and observed reaction wheel speed changes.

Drill drive mechanism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dressel, M.O.

1979-10-30

A drill drive mechanism is especially adapted to provide both rotational drive and axial feed for a drill of substantial diameter such as may be used for drilling holes for roof bolts in mine shafts. The drill shaft is made with a helical pattern of scroll-like projections on its surface for removal of cuttings. The drill drive mechanism includes a plurality of sprockets carrying two chains of drive links which are arranged to interlock around the drill shaft with each drive link having depressions which mate with the scroll-like projections. As the chain links move upwardly or downwardly the surfacesmore » of the depressions in the links mate with the scroll projections to move the shaft axially. Tangs on the drive links mate with notch surfaces between scroll projections to provide a means for rotating the shaft. Projections on the drive links mate together at the center to hold the drive links tightly around the drill shaft. The entire chain drive mechanism is rotated around the drill shaft axis by means of a hydraulic motor and gear drive to cause rotation of the drill shaft. This gear drive also connects with a differential gearset which is interconnected with a second gear. A second motor is connected to the spider shaft of the different gearset to produce differential movement (speeds) at the output gears of the differential gearset. This differential in speed is utilized to drive said second gear at a speed different from the speed of said gear drive, this speed differential being utilized to drive said sprockets for axial movement of said drill shaft. 11 claims.« less

Drill drive mechanism

DOEpatents

Dressel, Michael O.

1979-01-01

A drill drive mechanism is especially adapted to provide both rotational drive and axial feed for a drill of substantial diameter such as may be used for drilling holes for roof bolts in mine shafts. The drill shaft is made with a helical pattern of scroll-like projections on its surface for removal of cuttings. The drill drive mechanism includes a plurality of sprockets carrying two chains of drive links which are arranged to interlock around the drill shaft with each drive link having depressions which mate with the scroll-like projections. As the chain links move upwardly or downwardly the surfaces of the depressions in the links mate with the scroll projections to move the shaft axially. Tangs on the drive links mate with notch surfaces between scroll projections to provide a means for rotating the shaft. Projections on the drive links mate together at the center to hold the drive links tightly around the drill shaft. The entire chain drive mechanism is rotated around the drill shaft axis by means of a hydraulic motor and gear drive to cause rotation of the drill shaft. This gear drive also connects with a differential gearset which is interconnected with a second gear. A second motor is connected to the spider shaft of the differential gearset to produce differential movement (speeds) at the output gears of the differential gearset. This differential in speed is utilized to drive said second gear at a speed different from the speed of said gear drive, this speed differential being utilized to drive said sprockets for axial movement of said drill shaft.

Alcohol effects on simulated driving performance and self-perceptions of impairment in DUI offenders

PubMed Central

Van Dyke, Nicholas; Fillmore, Mark T.

2014-01-01

Drivers with a history of driving under the influence (DUI) of alcohol self-report heightened impulsivity and display reckless driving behaviors as indicated by increased rates of vehicle crashes, moving violations, and traffic tickets. Such poor behavioral self-regulation could also increase sensitivity to the disruptive effects of alcohol on driving performance. The present study examined the degree to which DUI drivers display an increased sensitivity to the acute impairing effects of alcohol on simulated driving performance and overestimate their driving fitness following alcohol consumption. Adult drivers with a history of DUI and a demographically-matched group of drivers with no history of DUI (controls) were tested following a 0.65 g/kg alcohol and a placebo. Results indicated that alcohol impaired several measures of driving performance and there was no difference between DUI offenders and controls in these impairments. However, following alcohol DUI drivers self-reported a greater ability and willingness to drive compared with controls. These findings indicate that drivers with a history of DUI might perceive themselves as more fit to drive after drinking which could play an important role in their decisions to drink and drive. PMID:25347077

Driver fatigue and highway driving: a simulator study.

PubMed

Ting, Ping-Huang; Hwang, Jiun-Ren; Doong, Ji-Liang; Jeng, Ming-Chang

2008-06-09

Long duration of driving is a significant cause of fatigue-related accidents on motorways or major roadways. The fatigue caused by driving for extended periods acutely impairs driver alertness and performance and can compromise transportation safety. This study quantitatively measured the progression of driver fatigue and identified the conservative safe duration of continuous highway driving. Thirty young male subjects were analyzed during 90 min of laboratory-simulated highway driving. Sleepiness ratings (SSS) and reaction time (RT) tests were used to assess impairment of driver alertness and vigilance. Additionally, various measures of driving performance recorded throughout the experiment were used to measure temporal deterioration of driver performance from alert to fatigued using principal component analysis (PCA). The analytical results revealed that SSS scores, reaction times (RTs) and unstable driving performance significantly increased over time, indicating that excessive driving time is a significant fatigue factor and potential cause of fatigue-related accidents. Moreover, the analytical results indicated that 80 min was the safe limit for monotonous highway driving. Based on the experimental findings of this study, public awareness of the adverse affects of driver fatigue during long-distance driving should be enhanced. This study provides explicit information of fatigue development that can be used to prevent fatigue-related accidents.

Alcohol effects on simulated driving performance and self-perceptions of impairment in DUI offenders.

PubMed

Van Dyke, Nicholas; Fillmore, Mark T

2014-12-01

Drivers with a history of driving under the influence (DUI) of alcohol self-report heightened impulsivity and display reckless driving behaviors as indicated by increased rates of vehicle crashes, moving violations, and traffic tickets. Such poor behavioral self-regulation could also increase sensitivity to the disruptive effects of alcohol on driving performance. The present study examined the degree to which DUI drivers display an increased sensitivity to the acute impairing effects of alcohol on simulated driving performance and overestimate their driving fitness following alcohol consumption. Adult drivers with a history of DUI and a demographically matched group of drivers with no history of DUI (controls) were tested following a 0.65 g/kg alcohol and a placebo. Results indicated that alcohol impaired several measures of driving performance, and there was no difference between DUI offenders and controls in these impairments. However, following alcohol, DUI drivers self-reported a greater ability and willingness to drive compared with controls. These findings indicate that drivers with a history of DUI might perceive themselves as more fit to drive after drinking, which could play an important role in their decisions to drink and drive. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Shuttle Main Propulsion System LH2 Feed Line and Inducer Simulations

NASA Technical Reports Server (NTRS)

Dorney, Daniel J.; Rothermel, Jeffry

2002-01-01

This viewgraph presentation includes simulations of the unsteady flow field in the LH2 feed line, flow line, flow liner, backing cavity and inducer of Shuttle engine #1. It also evaluates aerodynamic forcing functions which may contribute to the formation of the cracks observed on the flow liner slots. The presentation lists the numerical methods used, and profiles a benchmark test case.

Effects of simulated lightning on composite and metallic joints

NASA Technical Reports Server (NTRS)

Howell, W. E.; Plumer, J. A.

1982-01-01

The effects of simulated lightning strikes and currents on aircraft bonded joints and access/inspection panels were investigated. Both metallic and composite specimens were tested. Tests on metal fuel feed through elbows in graphite/epoxy structures were evaluated. Sparking threshold and residual strength of single lap bonded joints and sparking threshold of access/inspection panels and metal fuel feed through elbows are reported.

Comparison study on disturbance estimation techniques in precise slow motion control

NASA Astrophysics Data System (ADS)

Fan, S.; Nagamune, R.; Altintas, Y.; Fan, D.; Zhang, Z.

2010-08-01

Precise low speed motion control is important for the industrial applications of both micro-milling machine tool feed drives and electro-optical tracking servo systems. It calls for precise position and instantaneous velocity measurement and disturbance, which involves direct drive motor force ripple, guide way friction and cutting force etc., estimation. This paper presents a comparison study on dynamic response and noise rejection performance of three existing disturbance estimation techniques, including the time-delayed estimators, the state augmented Kalman Filters and the conventional disturbance observers. The design technique essentials of these three disturbance estimators are introduced. For designing time-delayed estimators, it is proposed to substitute Kalman Filter for Luenberger state observer to improve noise suppression performance. The results show that the noise rejection performances of the state augmented Kalman Filters and the time-delayed estimators are much better than the conventional disturbance observers. These two estimators can give not only the estimation of the disturbance but also the low noise level estimations of position and instantaneous velocity. The bandwidth of the state augmented Kalman Filters is wider than the time-delayed estimators. In addition, the state augmented Kalman Filters can give unbiased estimations of the slow varying disturbance and the instantaneous velocity, while the time-delayed estimators can not. The simulation and experiment conducted on X axis of a 2.5-axis prototype micro milling machine are provided.

EEG-based decoding of error-related brain activity in a real-world driving task

NASA Astrophysics Data System (ADS)

Zhang, H.; Chavarriaga, R.; Khaliliardali, Z.; Gheorghe, L.; Iturrate, I.; Millán, J. d. R.

2015-12-01

Objectives. Recent studies have started to explore the implementation of brain-computer interfaces (BCI) as part of driving assistant systems. The current study presents an EEG-based BCI that decodes error-related brain activity. Such information can be used, e.g., to predict driver’s intended turning direction before reaching road intersections. Approach. We executed experiments in a car simulator (N = 22) and a real car (N = 8). While subject was driving, a directional cue was shown before reaching an intersection, and we classified the presence or not of an error-related potentials from EEG to infer whether the cued direction coincided with the subject’s intention. In this protocol, the directional cue can correspond to an estimation of the driving direction provided by a driving assistance system. We analyzed ERPs elicited during normal driving and evaluated the classification performance in both offline and online tests. Results. An average classification accuracy of 0.698 ± 0.065 was obtained in offline experiments in the car simulator, while tests in the real car yielded a performance of 0.682 ± 0.059. The results were significantly higher than chance level for all cases. Online experiments led to equivalent performances in both simulated and real car driving experiments. These results support the feasibility of decoding these signals to help estimating whether the driver’s intention coincides with the advice provided by the driving assistant in a real car. Significance. The study demonstrates a BCI system in real-world driving, extending the work from previous simulated studies. As far as we know, this is the first online study in real car decoding driver’s error-related brain activity. Given the encouraging results, the paradigm could be further improved by using more sophisticated machine learning approaches and possibly be combined with applications in intelligent vehicles.

HEADWAY TIME AND CRASHES AMONG NOVICE TEENS AND EXPERIENCED ADULT DRIVERS IN A SIMULATED LEAD TRUCK BRAKING SCENARIO

PubMed Central

McDonald, Catherine C.; Seacrist, Thomas S.; Lee, Yi-Ching; Loeb, Helen; Kandadai, Venk; Winston, Flaura K.

2014-01-01

Summary Driving simulators can be used to evaluate driving performance under controlled, safe conditions. Teen drivers are at particular risk for motor vehicle crashes and simulated driving can provide important information on performance. We developed a new simulator protocol, the Simulated Driving Assessment (SDA), with the goal of providing a new tool for driver assessment and a common outcome measure for evaluation of training programs. As an initial effort to examine the validity of the SDA to differentiate performance according to experience, this analysis compared driving behaviors and crashes between novice teens (n=20) and experienced adults (n=17) on a high fidelity simulator for one common crash scenario, a rear-end crash. We examined headway time and crashes during a lead truck with sudden braking event in our SDA. We found that 35% of the novice teens crashed and none of the experienced adults crashed in this lead truck braking event; 50% of the teens versus 25% of the adults had a headway time <3 seconds at the time of truck braking. Among the 10 teens with <3 seconds headway time, 70% crashed. Among all participants with a headway time of 2–3 seconds, further investigation revealed descriptive differences in throttle position and brake pedal force when comparing teens who crashed, teens who did not crash and adults (none of whom crashed). Even with a relatively small sample, we found statistically significant differences in headway time for adults and teens, providing preliminary construct validation for our new SDA. PMID:25197724

Self-Regulation of Driving Behavior in People with Parkinson Disease.

PubMed

Stolwyk, Renerus J; Scally, Karen A; Charlton, Judith L; Bradshaw, John L; Iansek, Robert; Georgiou-Karistianis, Nellie

2015-06-01

To determine the extent and nature of driving self-regulation in drivers with Parkinson disease (PD) and factors associated with self-regulatory practices. Although people with PD have consistently been shown to have driving impairments, few studies have examined self-regulatory driving practices and their relationship to driving performance. We used a self-report driving questionnaire to examine driving self-regulation in 37 drivers with PD and 37 healthy age-matched controls. We also analyzed factors associated with self-regulatory practices, primarily demographic, disease-related, psychological, and simulated driving performance variables. The drivers with PD reported significantly higher rates of self-perceived decline in their driving ability (P=0.008) and driving significantly shorter distances per week (P=0.004) than controls. Unfamiliar situations (P=0.009), in-car distractions (P<0.001), low visibility conditions (P=0.004), and long journeys (P=0.003) were particularly challenging for the drivers with PD, and their pattern of driving avoidance mirrored these difficulties. The use of self-regulatory strategies among drivers with PD was associated with female sex (rho=0.42, P=0.009) and perceived decline in driving ability (rho=-0.55, P<0.001), but not with age or objective measures of disease severity, cognition, or simulated driving performance. Drivers with PD reported driving less overall and restricting their driving to avoid particularly difficult circumstances. Further research is warranted on effective use of self-regulation strategies to improve driving performance in people with PD.

Simulation of a synergistic six-post motion system on the flight simulator for advanced aircraft at NASA-Ames

NASA Technical Reports Server (NTRS)

Bose, S. C.; Parris, B. L.

1977-01-01

Motion system drive philosophy and corresponding real-time software have been developed for the purpose of simulating the characteristics of a typical synergistic Six-Post Motion System (SPMS) on the Flight Simulator for Advanced Aircraft (FSAA) at NASA-Ames which is a non-synergistic motion system. This paper gives a brief description of these two types of motion systems and the general methods of producing motion cues of the FSAA. An actuator extension transformation which allows the simulation of a typical SPMS by appropriate drive washout and variable position limiting is described.

Information driving force and its application in agent-based modeling

NASA Astrophysics Data System (ADS)

Chen, Ting-Ting; Zheng, Bo; Li, Yan; Jiang, Xiong-Fei

2018-04-01

Exploring the scientific impact of online big-data has attracted much attention of researchers from different fields in recent years. Complex financial systems are typical open systems profoundly influenced by the external information. Based on the large-scale data in the public media and stock markets, we first define an information driving force, and analyze how it affects the complex financial system. The information driving force is observed to be asymmetric in the bull and bear market states. As an application, we then propose an agent-based model driven by the information driving force. Especially, all the key parameters are determined from the empirical analysis rather than from statistical fitting of the simulation results. With our model, both the stationary properties and non-stationary dynamic behaviors are simulated. Considering the mean-field effect of the external information, we also propose a few-body model to simulate the financial market in the laboratory.

Driven to distraction: dual-Task studies of simulated driving and conversing on a cellular telephone.

PubMed

Strayer, D L; Johnston, W A

2001-11-01

Dual-task studies assessed the effects of cellular-phone conversations on performance of a simulated driving task. Performance was not disrupted by listening to radio broadcasts or listening to a book on tape. Nor was it disrupted by a continuous shadowing task using a handheld phone, ruling out, in this case, dual-task interpretations associated with holding the phone, listening, or speaking, However significant interference was observed in a word-generation variant of the shadowing task, and this deficit increased with the difficulty of driving. Moreover unconstrained conversations using either a handheld or a hands-free cell phone resulted in a twofold increase in the failure to detect simulated traffic signals and slower reactions to those signals that were detected. We suggest that cellular-phone use disrupts performance by diverting attention to an engaging cognitive context other than the one immediately associated with driving.

Distracted driving and associated crash risks : tech summary.

DOT National Transportation Integrated Search

2014-10-01

The main goal of this research was to utilize a driving simulator to measure the risks associated with three distractions that are routinely faced by the driving population: handheld phone conversation, texting, and front-seat passenger conversation....

Persistence of Trichinella spiralis in Rat Carcasses Experimentally Mixed in Different Feed

PubMed Central

Oivanen, L; Mikkonen, T; Haltia, L; Karhula, H; Saloniemi, H; Sukura, A

2002-01-01

Trichinella spiralis infected rat carcasses were incubated for 6 weeks in several animal feeds to assess how long Trichinella can present a risk for an outbreak in contaminated feeds. In groups of 6, 24 infected target rats were placed in silage, grained barley, propionic acid-preserved feed, and also into simulated pasture conditions. Test environments were sampled after one-, 2-, 4-, and 6-week-incubations. Trichinella larvae were recovered by digestion, and their infectivity was evaluated in rats. A two-week incubation reduced the number of recovered larvae, but still after 6 weeks low numbers were isolated from all feeds except from the experimental group simulating pasture conditions. After 2 weeks storage, the larvae were infective in all storage environments. However, up to 4 weeks, they survived only in the propionic acid-fermented feed and there in small numbers with reduced reproductive capability. This indicates the possibility of farm animals to get infection from rats or other infected material being hazardously mixed with hay or other feed. If silage is stored for at least one month before use, however, the risk from this forage appears to be minimized. PMID:12831173

Eye movements and hazard perception in active and passive driving

PubMed Central

Mackenzie, Andrew K.; Harris, Julie M.

2015-01-01

ABSTRACT Differences in eye movement patterns are often found when comparing passive viewing paradigms to actively engaging in everyday tasks. Arguably, investigations into visuomotor control should therefore be most useful when conducted in settings that incorporate the intrinsic link between vision and action. We present a study that compares oculomotor behaviour and hazard reaction times across a simulated driving task and a comparable, but passive, video-based hazard perception task. We found that participants scanned the road less during the active driving task and fixated closer to the front of the vehicle. Participants were also slower to detect the hazards in the driving task. Our results suggest that the interactivity of simulated driving places increased demand upon the visual and attention systems than simply viewing driving movies. We offer insights into why these differences occur and explore the possible implications of such findings within the wider context of driver training and assessment. PMID:26681913

Modeling Simple Driving Tasks with a One-Boundary Diffusion Model

PubMed Central

Ratcliff, Roger; Strayer, David

2014-01-01

A one-boundary diffusion model was applied to the data from two experiments in which subjects were performing a simple simulated driving task. In the first experiment, the same subjects were tested on two driving tasks using a PC-based driving simulator and the psychomotor vigilance test (PVT). The diffusion model fit the response time (RT) distributions for each task and individual subject well. Model parameters were found to correlate across tasks which suggests common component processes were being tapped in the three tasks. The model was also fit to a distracted driving experiment of Cooper and Strayer (2008). Results showed that distraction altered performance by affecting the rate of evidence accumulation (drift rate) and/or increasing the boundary settings. This provides an interpretation of cognitive distraction whereby conversing on a cell phone diverts attention from the normal accumulation of information in the driving environment. PMID:24297620

Decoupling control of steering and driving system for in-wheel-motor-drive electric vehicle

NASA Astrophysics Data System (ADS)

Zhang, Han; Zhao, Wanzhong

2018-02-01

To improve the maneuverability and stability of in-wheel-motor-drive electric vehicle, a control strategy based on nonlinear decoupling control method is proposed in this paper, realizing the coordinated control of the steering and driving system. At first, the nonlinear models of the in-wheel-motor-drive electric vehicle and its sub-system are constructed. Then the inverse system decoupling theory is applied to decompose the nonlinear system into several independent subsystems, which makes it possible to realize the coordinated control of each subsystem. Next, the μ-Synthesis theory is applied to eliminate the influence of model uncertainty, improving the stability, robustness and tracking performance of in-wheel-motor-drive electric vehicle. Simulation and experiment results and numerical analyses, based on the electric vehicle actuated by in-wheel-motors, prove that the proposed control method is effective to accomplish the decoupling control of the steering and driving system in both simulation and real practice.

Driving Intervention for Returning Combat Veterans.

PubMed

Classen, Sherrilene; Winter, Sandra; Monahan, Miriam; Yarney, Abraham; Link Lutz, Amanda; Platek, Kyle; Levy, Charles

2017-04-01

Increased crash incidence following deployment and veterans' reports of driving difficulty spurred traffic safety research for this population. We conducted an interim analysis on the efficacy of a simulator-based occupational therapy driving intervention (OT-DI) compared with traffic safety education (TSE) in a randomized controlled trial. During baseline and post-testing, OT-Driver Rehabilitation Specialists and one OT-Certified Driver Rehabilitation Specialist measured driving performance errors on a DriveSafety CDS-250 high-fidelity simulator. The intervention group ( n = 13) received three OT-DI sessions addressing driving errors and visual-search retraining. The control group ( n = 13) received three TSE sessions addressing personal factors and defensive driving. Based on Wilcoxon rank-sum analysis, the OT-DI group's errors were significantly reduced when comparing baseline with Post-Test 1 ( p < .0001) and comparing the OT-DI group with the TSE group at Post-Test 1 ( p = .01). These findings provide support for the efficacy of the OT-DI and set the stage for a future effectiveness study.

Combination and selection of traffic safety expert judgments for the prevention of driving risks.

PubMed

Cabello, Enrique; Conde, Cristina; de Diego, Isaac Martín; Moguerza, Javier M; Redchuk, Andrés

2012-11-02

In this paper, we describe a new framework to combine experts’ judgments for the prevention of driving risks in a cabin truck. In addition, the methodology shows how to choose among the experts the one whose predictions fit best the environmental conditions. The methodology is applied over data sets obtained from a high immersive cabin truck simulator in natural driving conditions. A nonparametric model, based in Nearest Neighbors combined with Restricted Least Squared methods is developed. Three experts were asked to evaluate the driving risk using a Visual Analog Scale (VAS), in order to measure the driving risk in a truck simulator where the vehicle dynamics factors were stored. Numerical results show that the methodology is suitable for embedding in real time systems.

Adapting a Driving Simulator to Study Pedestrians' Street-Crossing Decisions: A Feasibility Study.

PubMed

Jäger, M; Nyffeler, T; Müri, R; Mosimann, U P; Nef, T

2015-01-01

The decision when to cross a street safely is a challenging task that poses high demands on perception and cognition. Both can be affected by normal aging, neurodegenerative disorder, and brain injury, and there is an increasing interest in studying street-crossing decisions. In this article, we describe how driving simulators can be modified to study pedestrians' street-crossing decisions. The driving simulator's projection system and the virtual driving environment were used to present street-crossing scenarios to the participants. New sensors were added to measure when the test person starts to cross the street. Outcome measures were feasibility, usability, task performance, and visual exploration behavior, and were measured in 15 younger persons, 15 older persons, and 5 post-stroke patients. The experiments showed that the test is feasible and usable, and the selected difficulty level was appropriate. Significant differences in the number of crashes between young participants and patients (p = .001) as well as between healthy older participants and patients (p = .003) were found. When the approaching vehicle's speed is high, significant differences between younger and older participants were found as well (p = .038). Overall, the new test setup was well accepted, and we demonstrated that driving simulators can be used to study pedestrians' street-crossing decisions.

WTP Waste Feed Qualification: Glass Fabrication Unit Operation Testing Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stone, M. E.; Newell, J. D.; Johnson, F. C.

The waste feed qualification program is being developed to protect the Hanford Tank Waste Treatment and Immobilization Plant (WTP) design, safety basis, and technical basis by assuring waste acceptance requirements are met for each staged waste feed campaign prior to transfer from the Tank Operations Contractor to the feed receipt vessels inside the Pretreatment Facility. The Waste Feed Qualification Program Plan describes the three components of waste feed qualification: 1. Demonstrate compliance with the waste acceptance criteria 2. Determine waste processability 3. Test unit operations at laboratory scale. The glass fabrication unit operation is the final step in the processmore » demonstration portion of the waste feed qualification process. This unit operation generally consists of combining each of the waste feed streams (high-level waste (HLW) and low-activity waste (LAW)) with Glass Forming Chemicals (GFCs), fabricating glass coupons, performing chemical composition analysis before and after glass fabrication, measuring hydrogen generation rate either before or after glass former addition, measuring rheological properties before and after glass former addition, and visual observation of the resulting glass coupons. Critical aspects of this unit operation are mixing and sampling of the waste and melter feeds to ensure representative samples are obtained as well as ensuring the fabrication process for the glass coupon is adequate. Testing was performed using a range of simulants (LAW and HLW simulants), and these simulants were mixed with high and low bounding amounts of GFCs to evaluate the mixing, sampling, and glass preparation steps in shielded cells using laboratory techniques. The tests were performed with off-the-shelf equipment at the Savannah River National Laboratory (SRNL) that is similar to equipment used in the SRNL work during qualification of waste feed for the Defense Waste Processing Facility (DWPF) and other waste treatment facilities at the Savannah River Site. It is not expected that the exact equipment used during this testing will be used during the waste feed qualification testing for WTP, but functionally similar equipment will be used such that the techniques demonstrated would be applicable. For example, the mixing apparatus could use any suitable mixer capable of being remoted and achieving similar mixing speeds to those tested.« less

Environmental impacts of precision feeding programs applied in pig production.

PubMed

Andretta, I; Hauschild, L; Kipper, M; Pires, P G S; Pomar, C

2017-12-04

This study was undertaken to evaluate the effect that switching from conventional to precision feeding systems during the growing-finishing phase would have on the potential environmental impact of Brazilian pig production. Standard life-cycle assessment procedures were used, with a cradle-to-farm gate boundary. The inputs and outputs of each interface of the life cycle (production of feed ingredients, processing in the feed industry, transportation and animal rearing) were organized in a model. Grain production was independently characterized in the Central-West and South regions of Brazil, whereas the pigs were raised in the South region. Three feeding programs were applied for growing-finishing pigs: conventional phase feeding by group (CON); precision daily feeding by group (PFG) (whole herd fed the same daily adjusted diet); and precision daily feeding by individual (PFI) (diets adjusted daily to match individual nutrient requirements). Raising pigs (1 t pig BW at farm gate) in South Brazil under the CON feeding program using grain cultivated in the same region led to emissions of 1840 kg of CO2-eq, 13.1 kg of PO4-eq and 32.2 kg of SO2-eq. Simulations using grain from the Central-West region showed a greater climate change impact. Compared with the previous scenario, a 17% increase in climate change impact was found when simulating with soybeans produced in Central-West Brazil, whereas a 28% increase was observed when simulating with corn and soybeans from Central-West Brazil. Compared with the CON feeding program, the PFG and PFI programs reduced the potential environmental impact. Applying the PFG program mitigated the potential climate change impact and eutrophication by up to 4%, and acidification impact by up to 3% compared with the CON program. Making a further adjustment by feeding pigs according to their individual nutrient requirements mitigated the potential climate change impact by up to 6% and the potential eutrophication and acidification impact by up to 5% compared with the CON program. The greatest environmental gains associated with the adoption of precision feeding were observed when the diet combined soybeans from Central-West Brazil with corn produced in Southern Brazil. The results clearly show that precision feeding is an effective approach for improving the environmental sustainability of Brazilian pig production.

Stability and Workload of the Virtual Reality-Based Simulator-2.

PubMed

Kamaraj, Deepan C; Dicianno, Brad E; Mahajan, Harshal P; Buhari, Alhaji M; Cooper, Rory A

2016-07-01

To assess the stability of clinicians' and users' rating of electric-powered wheelchair (EPW) driving while using 4 different human-machine interfaces (HMIs) within the Virtual Reality-based SIMulator-version 2 (VRSIM-2) and in the real world (accounting for a total of 5 unique driving conditions). Within-subjects repeated-measures design. Simulation-based assessment in a research laboratory. A convenience sample of EPW athletes (N=21) recruited at the 31st National Veterans Wheelchair Games. Not applicable. Composite PMRT scores from the Power Mobility Road Test (PMRT); Raw Task Load Index; and the 6 subscale scores from the Task Load Index developed by the National Aeronautics and Space Administration (NASA-TLX). There was moderate stability (intraclass correlation coefficient between .50 and .75) in the total composite PMRT scores (P<.001) and the users' self-reported performance scores (P<.001) among the 5 driving conditions. There was a significant difference in the workload among the 5 different driving conditions as reflected by the Raw Task Load Index (P=.009). Subanalyses revealed this difference was due to the difference in the mental demand (P=.007) and frustration (P=.007) subscales. Post hoc analyses revealed that these differences in the NASA-TLX subscale scores were due to the differences between real-world and virtual driving scores, particularly attributable to the conditions (1 and 3) that lacked the rollers as a part of the simulation. Further design improvements in the simulator to increase immersion experienced by the EPW user, along with a standardized training program for clinicians to deliver PMRT in VRSIM-2, could improve the stability between the different HMIs and real-world driving. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

The Influence of Motion Cues on Driver-Vehicle Performance in a Simulator

NASA Technical Reports Server (NTRS)

Repa, B. S.; Leucht, P. M.; Wierwille, W. W.

1981-01-01

Four different motion base configurations were studied on driving simulator. Differently responding vehicles were simulated on each motion configurations and the effects of the vehicle characteristics on driver vehicle system performance, driver control activity, and driver opinion ratings of vehicle performance during driving are compared for different motion configurations. Data show that: (1)) the effects of changes in vehicle characteristics on the different objective and subjective measures of driver vehicle performance are not disguised by the lack of physical motion; (2) fixed base simulator can be used to draw inferences despite the lack of motion; (3) the presence of motion tends to reduce path keeping errors and driver control activity; (4) roll and yaw motions are recommended because of their marked influence on driver vehicle performance (5) the importance of motion increases as the driving maneuvers become more extreme.

A description of neck motor performance, neck pain, fatigue, and mental effort while driving in a sample with chronic whiplash-associated disorders.

PubMed

Takasaki, Hiroshi; Treleaven, Julia; Johnston, Venerina; Van den Hoorn, Wolbert; Rakotonirainy, Andry; Jull, Gwendolen

2014-08-01

Individuals with chronic whiplash-associated disorders (WADs) often note driving as a difficult task. This study's aims were to (1) compare, while driving, neck motor performance, mental effort, and fatigue in individuals with chronic WAD against healthy controls and (2) investigate the relationships of these variables and neck pain to self-reported driving difficulty in the WAD group. This study involved 14 participants in each group (WAD and control). Measures included self-reported driving difficulty and measures of neck pain intensity, overall fatigue, mental effort, and neck motor performance (head rotation and upper trapezius activity) while driving a simulator. The WAD group had greater absolute path of head rotation in a simulated city area and used greater mental effort (P = 0.04), but there were no differences in other measures while driving compared with the controls (all P ≥ 0.05). Self-reported driving difficulty correlated moderately with neck pain intensity, fatigue level, and maximum velocity of head rotation while driving in the WAD group (all P < 0.05). Individuals with chronic WAD do not seem to have impaired neck motor performance while driving yet use greater mental effort. Neck pain, fatigue, and maximum head rotation velocity could be potential contributors to self-reported driving difficulty in this group.

A review of feed efficiency in swine: biology and application.

PubMed

Patience, John F; Rossoni-Serão, Mariana C; Gutiérrez, Néstor A

2015-01-01

Feed efficiency represents the cumulative efficiency with which the pig utilizes dietary nutrients for maintenance, lean gain and lipid accretion. It is closely linked with energy metabolism, as the oxidation of carbon-containing components in the feed drive all metabolic processes. While much is known about nutrient utilization and tissue metabolism, blending these subjects into a discussion on feed efficiency has proven to be difficult. For example, while increasing dietary energy concentration will almost certainly increase feed efficiency, the correlation between dietary energy concentration and feed efficiency is surprisingly low. This is likely due to the plethora of non-dietary factors that impact feed efficiency, such as the environment and health as well as individual variation in maintenance requirements, body composition and body weight. Nonetheless, a deeper understanding of feed efficiency is critical at many levels. To individual farms, it impacts profitability. To the pork industry, it represents its competitive position against other protein sources. To food economists, it means less demand on global feed resources. There are environmental and other societal implications as well. Interestingly, feed efficiency is not always reported simply as a ratio of body weight gain to feed consumed. This review will explain why this arithmetic calculation, as simple as it initially seems, and as universally applied as it is in science and commerce, can often be misleading due to errors inherent in recording of both weight gain and feed intake. This review discusses the importance of feed efficiency, the manner in which it can be measured and reported, its basis in biology and approaches to its improvement. It concludes with a summary of findings and recommendations for future efforts.

Using an automated speed, steering, and gap control system and a collision warning system when driving in clear visibility and in fog

DOT National Transportation Integrated Search

1998-04-01

The effect on driving performance of using a speed, steering, and gap control system (SSGCS) and a collision warning system (CWS) was assessed in an experiment conducted in the Iowa Driving Simulator. Driving performance data were obtained from 52 dr...

Passenger and Cell Phone Conversations in Simulated Driving

ERIC Educational Resources Information Center

Drews, Frank A.; Pasupathi, Monisha; Strayer, David L.

2008-01-01

This study examines how conversing with passengers in a vehicle differs from conversing on a cell phone while driving. We compared how well drivers were able to deal with the demands of driving when conversing on a cell phone, conversing with a passenger, and when driving without any distraction. In the conversation conditions, participants were…

A brief peripheral motion contrast threshold test predicts older drivers' hazardous behaviors in simulated driving.

PubMed

Henderson, Steven; Woods-Fry, Heather; Collin, Charles A; Gagnon, Sylvain; Voloaca, Misha; Grant, John; Rosenthal, Ted; Allen, Wade

2015-05-01

Our research group has previously demonstrated that the peripheral motion contrast threshold (PMCT) test predicts older drivers' self-report accident risk, as well as simulated driving performance. However, the PMCT is too lengthy to be a part of a battery of tests to assess fitness to drive. Therefore, we have developed a new version of this test, which takes under two minutes to administer. We assessed the motion contrast thresholds of 24 younger drivers (19-32) and 25 older drivers (65-83) with both the PMCT-10min and the PMCT-2min test and investigated if thresholds were associated with measures of simulated driving performance. Younger participants had significantly lower motion contrast thresholds than older participants and there were no significant correlations between younger participants' thresholds and any measures of driving performance. The PMCT-10min and the PMCT-2min thresholds of older drivers' predicted simulated crash risk, as well as the minimum distance of approach to all hazards. This suggests that our tests of motion processing can help predict the risk of collision or near collision in older drivers. Thresholds were also correlated with the total lane deviation time, suggesting a deficiency in processing of peripheral flow and delayed detection of adjacent cars. The PMCT-2min is an improved version of a previously validated test, and it has the potential to help assess older drivers' fitness to drive. Copyright © 2015 Elsevier Ltd. All rights reserved.

Plant Chemistry and Local Adaptation of a Specialized Folivore

PubMed Central

Laukkanen, Liisa; Leimu, Roosa; Muola, Anne; Lilley, Marianna; Salminen, Juha-Pekka; Mutikainen, Pia

2012-01-01

Local adaptation is central for creating and maintaining spatial variation in plant-herbivore interactions. Short-lived insect herbivores feeding on long-lived plants are likely to adapt to their local host plants, because of their short generation time, poor dispersal, and geographically varying selection due to variation in plant defences. In a reciprocal feeding trial, we investigated the impact of geographic variation in plant secondary chemistry of a long-lived plant, Vincetoxicum hirundinaria, on among-population variation in local adaptation of a specialist leaf-feeding herbivore, Abrostola asclepiadis. The occurrence and degree of local adaptation varied among populations. This variation correlated with qualitative and quantitative differences in plant chemistry among the plant populations. These findings provide insights into the mechanisms driving variation in local adaptation in this specialized plant-herbivore interaction. PMID:22666493

Trade-off between jerk and time headway as an indicator of driving style

PubMed Central

Pekkanen, Jami; Lappi, Otto; Kosonen, Iisakki; Luttinen, Tapio; Summala, Heikki

2017-01-01

Variation in longitudinal control in driving has been discussed in both traffic psychology and transportation engineering. Traffic psychologists have concerned themselves with “driving style”, a habitual form of behavior marked by it’s stability, and its basis in psychological traits. Those working in traffic microsimulation have searched for quantitative ways to represent different driver-car systems in car following models. There has been unfortunately little overlap or theoretical consistency between these literatures. Here, we investigated relationships between directly observable measures (time headway, acceleration and jerk) in a simulated driving task where the driving context, vehicle and environment were controlled. We found individual differences in the way a trade-off was made between close but jerky vs. far and smooth following behavior. We call these “intensive” and “calm” driving, and suggest this trade-off can serve as an indicator of a possible latent factor underlying driving style. We posit that pursuing such latent factors for driving style may have implications for modelling driver heterogeneity across various domains in traffic simulation. PMID:29040291

Experimental modeling of the effect of hurricane wind forces on driving behavior and vehicle performance.

PubMed

Rodriguez, Jose M; Codjoe, Julius; Osman, Osama; Ishak, Sherif; Wolshon, Brian

2015-01-01

While traffic planning is important for developing a hurricane evacuation plan, vehicle performance on the roads during extreme weather conditions is critical to the success of the planning process. This novel study investigates the effect of gusty hurricane wind forces on the driving behavior and vehicle performance. The study explores how the parameters of a driving simulator could be modified to reproduce wind loadings experienced by three vehicle types (passenger car, ambulance, and bus) during gusty hurricane winds, through manipulation of appropriate software. Thirty participants were then tested on the modified driving simulator under five wind conditions (ranging from normal to hurricane category 4). The driving performance measures used were heading error and lateral displacement. The results showed that higher wind forces resulted in more varied and greater heading error and lateral displacement. The ambulance had the greatest heading errors and lateral displacements, which were attributed to its large lateral surface area and light weight. Two mathematical models were developed to estimate the heading error and lateral displacements for each of the vehicle types for a given change in lateral wind force. Through a questionnaire, participants felt the different characteristics while driving each vehicle type. The findings of this study demonstrate the valuable use of a driving simulator to model the behavior of different vehicle types and to develop mathematical models to estimate and quantify driving behavior and vehicle performance under hurricane wind conditions.

Testing thermal gradient driving force for grain boundary migration using molecular dynamics simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bai, Xian-Ming; Zhang, Yongfeng; Tonks, Michael R.

2015-02-01

Strong thermal gradients in low-thermal-conductivity ceramics may drive extended defects, such as grain boundaries and voids, to migrate in preferential directions. In this work, molecular dynamics simulations are conducted to study thermal gradient driven grain boundary migration and to verify a previously proposed thermal gradient driving force equation, using uranium dioxide as a model system. It is found that a thermal gradient drives grain boundaries to migrate up the gradient and the migration velocity increases under a constant gradient owing to the increase in mobility with temperature. Different grain boundaries migrate at very different rates due to their different intrinsicmore » mobilities. The extracted mobilities from the thermal gradient driven simulations are compared with those calculated from two other well-established methods and good agreement between the three different methods is found, demonstrating that the theoretical equation of the thermal gradient driving force is valid, although a correction of one input parameter should be made. The discrepancy in the grain boundary mobilities between modeling and experiments is also discussed.« less

Two-way communication between SecY and SecA suggests a Brownian ratchet mechanism for protein translocation.

PubMed

Allen, William John; Corey, Robin Adam; Oatley, Peter; Sessions, Richard Barry; Baldwin, Steve A; Radford, Sheena E; Tuma, Roman; Collinson, Ian

2016-05-16

The essential process of protein secretion is achieved by the ubiquitous Sec machinery. In prokaryotes, the drive for translocation comes from ATP hydrolysis by the cytosolic motor-protein SecA, in concert with the proton motive force (PMF). However, the mechanism through which ATP hydrolysis by SecA is coupled to directional movement through SecYEG is unclear. Here, we combine all-atom molecular dynamics (MD) simulations with single molecule FRET and biochemical assays. We show that ATP binding by SecA causes opening of the SecY-channel at long range, while substrates at the SecY-channel entrance feed back to regulate nucleotide exchange by SecA. This two-way communication suggests a new, unifying 'Brownian ratchet' mechanism, whereby ATP binding and hydrolysis bias the direction of polypeptide diffusion. The model represents a solution to the problem of transporting inherently variable substrates such as polypeptides, and may underlie mechanisms of other motors that translocate proteins and nucleic acids.

A Polarization Reconfigurable Slot Antenna with a Novel Switchable Feeding Network

NASA Astrophysics Data System (ADS)

Xie, Peng; Wang, Guang Ming

2017-12-01

A polarization reconfigurable slot antenna is proposed in this paper. The antenna consists of a microstrip line-to-slotline transition structure, two radiation slots and a switchable feeding network. The feeding network is a gradually changed ring slot with six switching diodes on it. By controlling the diodes states, the antenna can generate y-direction polarization, z-direction polarization, left-hand circular polarization and right-hand circular polarization. Detailed design considerations of the proposed antenna, simulated and measured results are presented and discussed. Measured results agree well with simulated. The results proved that the antenna can realize polarization reconfiguration effectively at 5 GHz.

The useful field of view assessment predicts simulated commercial motor vehicle driving safety.

PubMed

McManus, Benjamin; Heaton, Karen; Vance, David E; Stavrinos, Despina

2016-10-02

The Useful Field of View (UFOV) assessment, a measure of visual speed of processing, has been shown to be a predictive measure of motor vehicle collision (MVC) involvement in an older adult population, but it remains unknown whether UFOV predicts commercial motor vehicle (CMV) driving safety during secondary task engagement. The purpose of this study is to determine whether the UFOV assessment predicts simulated MVCs in long-haul CMV drivers. Fifty licensed CMV drivers (Mage = 39.80, SD = 8.38, 98% male, 56% Caucasian) were administered the 3-subtest version of the UFOV assessment, where lower scores measured in milliseconds indicated better performance. CMV drivers completed 4 simulated drives, each spanning approximately a 22.50-mile distance. Four secondary tasks were presented to participants in a counterbalanced order during the drives: (a) no secondary task, (b) cell phone conversation, (c) text messaging interaction, and (d) e-mailing interaction with an on-board dispatch device. The selective attention subtest significantly predicted simulated MVCs regardless of secondary task. Each 20 ms slower on subtest 3 was associated with a 25% increase in the risk of an MVC in the simulated drive. The e-mail interaction secondary task significantly predicted simulated MVCs with a 4.14 times greater risk of an MVC compared to the no secondary task condition. Subtest 3, a measure of visual speed of processing, significantly predicted MVCs in the email interaction task. Each 20 ms slower on subtest 3 was associated with a 25% increase in the risk of an MVC during the email interaction task. The UFOV subtest 3 may be a promising measure to identify CMV drivers who may be at risk for MVCs or in need of cognitive training aimed at improving speed of processing. Subtest 3 may also identify CMV drivers who are particularly at risk when engaged in secondary tasks while driving.

Foulant Analysis of Three RO Membranes Used in Treating Simulated Brackish Water of the Iraqi Marshes

PubMed Central

Sachit, Dawood Eisa; Veenstra, John N.

2017-01-01

In this work, three different types of Reverse Osmosis (RO) (Thin-Film Composite (SE), Cellulose Acetate (CE), and Polyamide (AD)) were used to perform foulant analysis (autopsy) study on the deposited materials from three different simulated brackish surface feed waters. The brackish surface water qualities represented the water quality in Iraqi marshes. The main foulants from the simulated feed waters were characterized by using Scanning Electron Microscope (SEM) images and Energy-Dispersive X-ray Spectroscopy (EDXS) spectra. The effect of feed water temperatures (37 °C and 11 °C) on the formation of the fouled material deposited on the membrane surface was examined in this study. Also, pretreatment by a 0.1 micron microfiltration (MF) membrane of the simulated feed water in advance of the RO membrane on the precipitated material on the membrane surface was investigated. Finally, Fourier Transform Infrared Spectroscopy (FTIR) analysis was used to identify the functional groups of the organic matter deposited on the RO membrane surfaces. The SEM images and EDSX spectra suggested that the fouled material was mainly organic matter, and the major crystal deposited on the RO membrane was calcium carbonate (CaCO3). The FTIR spectra of the fouled RO membranes suggested that the constituents of the fouled material included aliphatic and aromatic compounds. PMID:28406468

A Novel Assessment of Braking Reaction Time Following THA Using a New Fully Interactive Driving Simulator.

PubMed

Ruel, Allison V; Lee, Yuo-Yu; Boles, John; Boettner, Friedrich; Su, Edwin; Westrich, Geoffrey H

2015-07-01

After total hip replacement surgery, patients are eager to resume the activities of daily life, particularly driving. Most surgeons recommend waiting 6 weeks after surgery to resume driving; however, there is no evidence to indicate that patients cannot resume driving earlier. Our purpose was to evaluate when in the recovery period following THA that patients regain or improve upon their preoperative braking reaction time, allowing them to safely resume driving. We measured and compared pre- and postoperative braking reaction times of 90 patients from 3 different surgeons using a Fully Interactive Driving Simulator (Simulator Systems International, Tulsa, OK). We defined a return to safe braking reaction time as a return to a time value that is either equal to or less than the preoperative braking reaction time. Patients tested at 2 and 3 weeks after surgery had slower braking reaction times than preoperative times by an average of 0.069 and 0.009 s, respectively. At 4 weeks after surgery, however, patients improved their reaction times by 0.035 s (p = 0.0398). In addition, at 2, 3, and 4 weeks postoperatively, the results also demonstrated that patient less than 70 years of age recovered faster. Based upon the results of this study, most patients should be allowed to return to driving 4 weeks following minimally invasive primary total hip arthroplasty.

The role of effort in moderating the anxiety-performance relationship: Testing the prediction of processing efficiency theory in simulated rally driving.

PubMed

Wilson, Mark; Smith, Nickolas C; Chattington, Mark; Ford, Mike; Marple-Horvat, Dilwyn E

2006-11-01

We tested some of the key predictions of processing efficiency theory using a simulated rally driving task. Two groups of participants were classified as either dispositionally high or low anxious based on trait anxiety scores and trained on a simulated driving task. Participants then raced individually on two similar courses under counterbalanced experimental conditions designed to manipulate the level of anxiety experienced. The effort exerted on the driving tasks was assessed though self-report (RSME), psychophysiological measures (pupil dilation) and visual gaze data. Efficiency was measured in terms of efficiency of visual processing (search rate) and driving control (variability of wheel and accelerator pedal) indices. Driving performance was measured as the time taken to complete the course. As predicted, increased anxiety had a negative effect on processing efficiency as indexed by the self-report, pupillary response and variability of gaze data. Predicted differences due to dispositional levels of anxiety were also found in the driving control and effort data. Although both groups of drivers performed worse under the threatening condition, the performance of the high trait anxious individuals was affected to a greater extent by the anxiety manipulation than the performance of the low trait anxious drivers. The findings suggest that processing efficiency theory holds promise as a theoretical framework for examining the relationship between anxiety and performance in sport.

Exploring the association between working memory and driving performance in Parkinson's disease.

PubMed

Vardaki, Sophia; Devos, Hannes; Beratis, Ion; Yannis, George; Papageorgiou, Sokratis G

2016-05-18

The aim of this study was to explore whether varying levels of operational and tactical driving task demand differentially affect drivers with Parkinson's disease (PD) and control drivers in their sign recall. Study participants aged between 50 and 70 years included a group of drivers with PD (n = 10) and a group of age- and sex-matched control drivers (n = 10). Their performance in a sign recall task was measured using a driving simulator. Drivers in the control group performed better than drivers with PD in a sign recall task, but this trend was not statistically significant (P =.43). In addition, regardless of group membership, subjects' performance differed according to varying levels of task demand. Performance in the sign recall task was more likely to drop with increasing task demand (P =.03). This difference was significant when the variation in task demand was associated with a cognitive task; that is, when drivers were required to apply the instructions from working memory. Although the conclusions drawn from this study are tentative, the evidence presented here is encouraging with regard to the use of a driving simulator to examine isolated cognitive functions underlying driving performance in PD. With an understanding of its limitations, such driving simulation in combination with functional assessment batteries measuring physical, visual, and cognitive abilities could comprise one component of a multitiered system to evaluate medical fitness to drive.

Propulsion Electric Grid Simulator (PEGS) for Future Turboelectric Distributed Propulsion Aircraft

NASA Technical Reports Server (NTRS)

Choi, Benjamin B.; Morrison, Carlos; Dever, Timothy; Brown, Gerald V.

2014-01-01

NASA Glenn Research Center, in collaboration with the aerospace industry and academia, has begun the development of technology for a future hybrid-wing body electric airplane with a turboelectric distributed propulsion (TeDP) system. It is essential to design a subscale system to emulate the TeDP power grid, which would enable rapid analysis and demonstration of the proof-of-concept of the TeDP electrical system. This paper describes how small electrical machines with their controllers can emulate all the components in a TeDP power train. The whole system model in Matlab/Simulink was first developed and tested in simulation, and the simulation results showed that system dynamic characteristics could be implemented by using the closed-loop control of the electric motor drive systems. Then we designed a subscale experimental system to emulate the entire power system from the turbine engine to the propulsive fans. Firstly, we built a system to emulate a gas turbine engine driving a generator, consisting of two permanent magnet (PM) motors with brushless motor drives, coupled by a shaft. We programmed the first motor and its drive to mimic the speed-torque characteristic of the gas turbine engine, while the second motor and drive act as a generator and produce a torque load on the first motor. Secondly, we built another system of two PM motors and drives to emulate a motor driving a propulsive fan. We programmed the first motor and drive to emulate a wound-rotor synchronous motor. The propulsive fan was emulated by implementing fan maps and flight conditions into the fourth motor and drive, which produce a torque load on the driving motor. The stator of each PM motor is designed to travel axially to change the coupling between rotor and stator. This feature allows the PM motor to more closely emulate a wound-rotor synchronous machine. These techniques can convert the plain motor system into a unique TeDP power grid emulator that enables real-time simulation performance using hardware-in-the-loop (HIL).

Effect of SBR feeding strategy and feed composition on the stability of aerobic granular sludge in the treatment of a simulated textile wastewater.

PubMed

Franca, R D G; Ortigueira, J; Pinheiro, H M; Lourenço, N D

2017-09-01

Treatment of the highly polluting and variable textile industry wastewater using aerobic granular sludge (AGS) sequencing batch reactors (SBRs) has been recently suggested. Aiming to develop this technology application, two feeding strategies were compared regarding the capacity of anaerobic-aerobic SBRs to deal with disturbances in the composition of the simulated textile wastewater feed. Both a statically fed, anaerobic-aerobic SBR and an anaerobic plug-flow fed, anaerobic-aerobic SBR could cope with shocks of high azo dye concentration and organic load, the overall chemical oxygen demand and color removal yields being rapidly restored to 80%. Yet, subsequent azo dye metabolite bioconversion was not observed, along the 315-day run. Moreover, switching from a starch-based substrate to acetate in the feed composition deteriorated AGS stability. Overall, the plug-flow fed SBR recovered more rapidly from the imposed disturbances. Further research is needed towards guaranteeing long-term AGS stability during the treatment of textile wastewater.

Bilastine safety in drivers who need antihistamines: new evidence from high-speed simulator driving test on allergic patients.

PubMed

Demonte, A; Guanti, M B; Liberati, S; Biffi, A; Fernando, F; Fainello, M; Pepe, P

2018-02-01

Bilastine is a highly selective, non-sedating antihistamine, indicated for the symptomatic treatment of allergic rhinoconjunctivitis and urticaria. Available data suggest that bilastine interferes neither with driving ability nor with flying-related performance. However, no data are available on the effect of bilastine on the driving ability in extreme conditions. Here we analyzed the effect of 7 days treatment with 20 mg bilastine in patients with allergic rhinitis and/or chronic urticaria, on psychophysical performance assessed by the Formula One (F1) high-speed simulator-driving test. This study is a phase IV, interventional, prospective, mono-centric, single arm, open-label trial. Eighteen outpatients affected by allergic rhinitis and/or chronic urticaria, able to perform a preliminary driving test on F1 simulator were considered (V-1). First, the patients had a screening visit to assess their eligibility (V0). Visit 1 (V1), at the end of placebo before bilastine treatment and Visit 2 (V2), at the end of bilastine treatment. The primary variable parameter was the ability to maintain the vehicle in a central position at different speeds (50, 150, and 250 km/h). Bilastine had a good safety profile and was well tolerated in terms of adverse events, laboratory parameters and vital signs. Bilastine did not have any negative effect on the ability to maintain the requested path, a constant speed as well as on attention and reactivity levels, even in extreme driving conditions. This study is the first done in patients with allergic rhinitis and/or chronic urticaria using a F1-high speed simulator-driving test evaluating subjects' performance under bilastine treatment.

Eddy-driven low-frequency variability: physics and observability through altimetry

NASA Astrophysics Data System (ADS)

Penduff, Thierry; Sérazin, Guillaume; Arbic, Brian; Mueller, Malte; Richman, James G.; Shriver, Jay F.; Morten, Andrew J.; Scott, Robert B.

2015-04-01

Model studies have revealed the propensity of the eddying ocean circulation to generate strong low-frequency variability (LFV) intrinsically, i.e. without low-frequency atmospheric variability. In the present study, gridded satellite altimeter products, idealized quasi-geostrophic (QG) turbulent simulations, and realistic high-resolution global ocean simulations are used to study the spontaneous tendency of mesoscale (relatively high frequency and high wavenumber) kinetic energy to non-linearly cascade towards larger time and space scales. The QG model reveals that large-scale variability, arising from the well-known spatial inverse cascade, is associated with low frequencies. Low-frequency, low-wavenumber energy is maintained primarily by nonlinearities in the QG model, with forcing (by large-scale shear) and friction playing secondary roles. In realistic simulations, nonlinearities also generally drive kinetic energy to low frequencies and low wavenumbers. In some, but not all, regions of the gridded altimeter product, surface kinetic energy is also found to cascade toward low frequencies. Exercises conducted with the realistic model suggest that the spatial and temporal filtering inherent in the construction of gridded satellite altimeter maps may contribute to the discrepancies seen in some regions between the direction of frequency cascade in models versus gridded altimeter maps. Finally, the range of frequencies that are highly energized and engaged these cascades appears much greater than the range of highly energized and engaged wavenumbers. Global eddying simulations, performed in the context of the CHAOCEAN project in collaboration with the CAREER project, provide estimates of the range of timescales that these oceanic nonlinearities are likely to feed without external variability.

Municipality Level Simulations of Dengue Fever Incidence in Puerto Rico Using Ground Based and Remotely Sensed Climate Data

NASA Technical Reports Server (NTRS)

Quattrochi, Dale A.; Morin, Cory

2015-01-01

Dengue fever (DF) is caused by a virus transmitted between humans and Aedes genus mosquitoes through blood feeding. In recent decades incidence of the disease has drastically increased in the tropical Americas, culminating with the Pan American outbreak in 2010 which resulted in 1.7 million reported cases. In Puerto Rico dengue is endemic, however, there is significant inter-annual, intraannual, and spatial variability in case loads. Variability in climate and the environment, herd immunity and virus genetics, and demographic characteristics may all contribute to differing patterns of transmission both spatially and temporally. Knowledge of climate influences on dengue incidence could facilitate development of early warning systems allowing public health workers to implement appropriate transmission intervention strategies. In this study, we simulate dengue incidence in several municipalities in Puerto Rico using population and meteorological data derived from ground based stations and remote sensing instruments. This data was used to drive a process based model of vector population development and virus transmission. Model parameter values for container composition, vector characteristics, and incubation period were chosen by employing a Monte Carlo approach. Multiple simulations were performed for each municipality and the results were compared with reported dengue cases. The best performing simulations were retained and their parameter values and meteorological input were compared between years and municipalities. Parameter values varied by municipality and year illustrating the complexity and sensitivity of the disease system. Local characteristics including the natural and built environment impact transmission dynamics and produce varying responses to meteorological conditions.

Metabolic demands and replenishment of muscle glycogen after a rugby league match simulation protocol.

PubMed

Bradley, Warren J; Hannon, Marcus P; Benford, Victoria; Morehen, James C; Twist, Craig; Shepherd, Sam; Cocks, Matthew; Impey, Samuel G; Cooper, Robert G; Morton, James P; Close, Graeme L

2017-09-01

The metabolic requirements of a rugby league match simulation protocol and the timing of carbohydrate provision on glycogen re-synthesis in damaged muscle were examined. Fifteen (mean±SD: age 20.9±2.9 year, body-mass 87.3±14.1kg, height 177.4±6.0cm) rugby league (RL) players consumed a 6gkgday-1 CHO diet for 7-days, completed a time to exhaustion test (TTE) and a glycogen depletion protocol on day-3, a RL simulated-match protocol (RLMSP) on day-5 and a TTE on day-7. Players were prescribed an immediate or delayed (2-h-post) re-feed post-simulation. Muscle biopsies and blood samples were obtained post-depletion, before and after simulated match-play, and 48-h after match-play with PlayerLoad and heart-rate collected throughout the simulation. Data were analysed using effects sizes±90% CI and magnitude-based inferences. PlayerLoad (8.0±0.7 AUmin-1) and %HRpeak (83±4.9%) during the simulation were similar to values reported for RL match-play. Muscle glycogen very likely increased from immediately after to 48-h post-simulation (272±97 cf. 416±162mmolkg-1d.w.; ES±90%CI) after immediate re-feed, but changes were unclear (283±68 cf. 361±144mmolkg-1d.w.; ES±90%CI) after delayed re-feed. CK almost certainly increased by 77.9±25.4% (0.75±0.19) post-simulation for all players. The RLMSP presents a replication of the internal loads associated with professional RL match-play, although difficulties in replicating the collision reduced the metabolic demands and glycogen utilisation. Further, it is possible to replete muscle glycogen in damaged muscle employing an immediate re-feed strategy. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Impact of distraction on the driving performance of adolescents with and without attention-deficit/hyperactivity disorder.

PubMed

Narad, Megan; Garner, Annie A; Brassell, Anne A; Saxby, Dyani; Antonini, Tanya N; O'Brien, Kathleen M; Tamm, Leanne; Matthews, Gerald; Epstein, Jeffery N

2013-10-01

This study extends the literature regarding attention-deficit/hyperactivity disorder (ADHD)-related driving impairments to a newly licensed, adolescent population. To investigate the combined risks of adolescence, ADHD, and distracted driving (cell phone conversation and text messaging) on driving performance. Adolescents aged 16 to 17 years with (n = 28) and without (n = 33) ADHD engaged in a simulated drive under 3 conditions (no distraction, cell phone conversation, and texting). During each condition, one unexpected event (eg, another car suddenly merging into driver's lane) was introduced. Cell phone conversation, texting, and no distraction while driving. Self-report of driving history, average speed, standard deviation of speed, standard deviation of lateral position, and braking reaction time during driving simulation. Adolescents with ADHD reported fewer months of driving experience and a higher proportion of driving violations than control subjects. After controlling for months of driving history, adolescents with ADHD demonstrated more variability in speed and lane position than control subjects. There were no group differences for braking reaction time. Furthermore, texting negatively impacted the driving performance of all participants as evidenced by increased variability in speed and lane position. To our knowledge, this study is one of the first to investigate distracted driving in adolescents with ADHD and adds to a growing body of literature documenting that individuals with ADHD are at increased risk for negative driving outcomes. Furthermore, texting significantly impairs the driving performance of all adolescents and increases existing driving-related impairment in adolescents with ADHD, highlighting the need for education and enforcement of regulations against texting for this age group.

A Subset of Serotonergic Neurons Evokes Hunger in Adult Drosophila.

PubMed

Albin, Stephanie D; Kaun, Karla R; Knapp, Jon-Michael; Chung, Phuong; Heberlein, Ulrike; Simpson, Julie H

2015-09-21

Hunger is a complex motivational state that drives multiple behaviors. The sensation of hunger is caused by an imbalance between energy intake and expenditure. One immediate response to hunger is increased food consumption. Hunger also modulates behaviors related to food seeking such as increased locomotion and enhanced sensory sensitivity in both insects and vertebrates. In addition, hunger can promote the expression of food-associated memory. Although progress is being made, how hunger is represented in the brain and how it coordinates these behavioral responses is not fully understood in any system. Here, we use Drosophila melanogaster to identify neurons encoding hunger. We found a small group of neurons that, when activated, induced a fed fly to eat as though it were starved, suggesting that these neurons are downstream of the metabolic regulation of hunger. Artificially activating these neurons also promotes appetitive memory performance in sated flies, indicating that these neurons are not simply feeding command neurons but likely play a more general role in encoding hunger. We determined that the neurons relevant for the feeding effect are serotonergic and project broadly within the brain, suggesting a possible mechanism for how various responses to hunger are coordinated. These findings extend our understanding of the neural circuitry that drives feeding and enable future exploration of how state influences neural activity within this circuit. Copyright © 2015 Elsevier Ltd. All rights reserved.

Impact of Methylphenidate Delivery Profiles on Driving Performance of Adolescents with Attention-Deficit/hyperactivity Disorder: A Pilot Study

ERIC Educational Resources Information Center

Cox, Daniel J.; Merkel, R. Lawrence; Penberthy, Jennifer Kim; Kovatchev, Boris; Hankin, Cheryl S.

2004-01-01

Objective: Adolescents with attention-deficit/hyperactivity disorder (ADHD) are at high risk for driving accidents. One dose of methylphenidate (MPH) improves simulator driving performances of ADHD-diagnosed adolescents at 1.5 hours post-dose. However, little is known about the effects of different MPH delivery profiles on driving performance…

A Pilot Study Assessing Performance and Visual Attention of Teenagers with ASD in a Novel Adaptive Driving Simulator.

PubMed

Wade, Joshua; Weitlauf, Amy; Broderick, Neill; Swanson, Amy; Zhang, Lian; Bian, Dayi; Sarkar, Medha; Warren, Zachary; Sarkar, Nilanjan

2017-11-01

Individuals with Autism Spectrum Disorder (ASD), compared to typically-developed peers, may demonstrate behaviors that are counter to safe driving. The current work examines the use of a novel simulator in two separate studies. Study 1 demonstrates statistically significant performance differences between individuals with (N = 7) and without ASD (N = 7) with regards to the number of turning-related driving errors (p < 0.01). Study 2 shows that both the performance-based feedback group (N = 9) and combined performance- and gaze-sensitive feedback group (N = 8) achieved statistically significant reductions in driving errors following training (p < 0.05). These studies are the first to present results of fine-grained measures of visual attention of drivers and an adaptive driving intervention for individuals with ASD.

Novel Digital Driving Method Using Dual Scan for Active Matrix Organic Light-Emitting Diode Displays

NASA Astrophysics Data System (ADS)

Jung, Myoung Hoon; Choi, Inho; Chung, Hoon-Ju; Kim, Ohyun

2008-11-01

A new digital driving method has been developed for low-temperature polycrystalline silicon, transistor-driven, active-matrix organic light-emitting diode (AM-OLED) displays by time-ratio gray-scale expression. This driving method effectively increases the emission ratio and the number of subfields by inserting another subfield set into nondisplay periods in the conventional digital driving method. By employing the proposed modified gravity center coding, this method can be used to effectively compensate for dynamic false contour noise. The operation and performance were verified by current measurement and image simulation. The simulation results using eight test images show that the proposed approach improves the average peak signal-to-noise ratio by 2.61 dB, and the emission ratio by 20.5%, compared with the conventional digital driving method.

Simulating the dynamic behavior of chain drive systems by advanced CAE programs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ross, J.; Meyer, J.

1996-09-01

Due to the increased requirements for chain drive systems of 4-stroke internal combustion engines CAE-tools are necessary to design the optimum dynamic system. In comparison to models used din the past the advantage of the new model CDD (Chain Drive Dynamics) is the capability of simulating the trajectory of each chain link around the drive system. Each chain link is represented by a mass with two degrees of freedom and is coupled to the next by a spring-damper element. The drive sprocket can be moved with a constant or non-constant speed. As in reality the other sprockets are driven bymore » the running chain and can be excited by torques. Due to these unique model features it is possible to calculate all vibration types of the chain, polygon effects and radial or angular vibrations of the sprockets very accurately. The model includes the detailed simulation of a mechanical or a hydraulic tensioner as well. The method is ready to be coupled to other detailed calculation models (e.g. valve train systems, crankshaft, etc.). The high efficiency of the tool predicting the dynamic and acoustic behavior of a chain drive system will be demonstrated in comparison to measurements.« less

A Pilot Study Assessing Performance and Visual Attention of Teenagers with ASD in a Novel Adaptive Driving Simulator

ERIC Educational Resources Information Center

Wade, Joshua; Weitlauf, Amy; Broderick, Neill; Swanson, Amy; Zhang, Lian; Bian, Dayi; Sarkar, Medha; Warren, Zachary; Sarkar, Nilanjan

2017-01-01

Individuals with Autism Spectrum Disorder (ASD), compared to typically-developed peers, may demonstrate behaviors that are counter to safe driving. The current work examines the use of a novel simulator in two separate studies. Study 1 demonstrates statistically significant performance differences between individuals with (N = 7) and without ASD…

Increasing Following Headway with Prompts, Goal Setting, and Feedback in a Driving Simulator

ERIC Educational Resources Information Center

Arnold, Michelle L.; Van Houten, Ron

2011-01-01

We evaluated the effects of prompting, goal setting, and feedback on following headway of young drivers in a simulated driving environment and assessed whether changes produced in following headway were associated with reductions in hard braking when drivers were and were not using cell phones. Participants were 4 university students. During…

The doubling of stellar black hole nuclei

NASA Astrophysics Data System (ADS)

Kazandjian, Mher V.; Touma, J. R.

2013-04-01

It is strongly believed that Andromeda's double nucleus signals a disc of stars revolving around its central supermassive black hole on eccentric Keplerian orbits with nearly aligned apsides. A self-consistent stellar dynamical origin for such apparently long-lived alignment has so far been lacking, with indications that cluster self-gravity is capable of sustaining such lopsided configurations if and when stimulated by external perturbations. Here, we present results of N-body simulations which show unstable counter-rotating stellar clusters around supermassive black holes saturating into uniformly precessing lopsided nuclei. The double nucleus in our featured experiment decomposes naturally into a thick eccentric disc of apo-apse aligned stars which is embedded in a lighter triaxial cluster. The eccentric disc reproduces key features of Keplerian disc models of Andromeda's double nucleus; the triaxial cluster has a distinctive kinematic signature which is evident in Hubble Space Telescope observations of Andromeda's double nucleus, and has been difficult to reproduce with Keplerian discs alone. Our simulations demonstrate how the combination of an eccentric disc and a triaxial cluster arises naturally when a star cluster accreted over a preexisting and counter-rotating disc of stars drives disc and cluster into a mutually destabilizing dance. Such accretion events are inherent to standard galaxy formation scenarios. They are here shown to double stellar black hole nuclei as they feed them.

Driving-forces model on individual behavior in scenarios considering moving threat agents

NASA Astrophysics Data System (ADS)

Li, Shuying; Zhuang, Jun; Shen, Shifei; Wang, Jia

2017-09-01

The individual behavior model is a contributory factor to improve the accuracy of agent-based simulation in different scenarios. However, few studies have considered moving threat agents, which often occur in terrorist attacks caused by attackers with close-range weapons (e.g., sword, stick). At the same time, many existing behavior models lack validation from cases or experiments. This paper builds a new individual behavior model based on seven behavioral hypotheses. The driving-forces model is an extension of the classical social force model considering scenarios including moving threat agents. An experiment was conducted to validate the key components of the model. Then the model is compared with an advanced Elliptical Specification II social force model, by calculating the fitting errors between the simulated and experimental trajectories, and being applied to simulate a specific circumstance. Our results show that the driving-forces model reduced the fitting error by an average of 33.9% and the standard deviation by an average of 44.5%, which indicates the accuracy and stability of the model in the studied situation. The new driving-forces model could be used to simulate individual behavior when analyzing the risk of specific scenarios using agent-based simulation methods, such as risk analysis of close-range terrorist attacks in public places.

Effects of practice on interference from an auditory task while driving : a simulation study

DOT National Transportation Integrated Search

2004-12-01

Experimental research on the effects of cellular phone conversations on driving indicates that the phone task interferes with many driving-related functions, especially with older drivers. Limitations of past research have been that (1) the dual task...

An investigation of the effects of reading and writing text-based messages while driving.

DOT National Transportation Integrated Search

2012-08-01

Previous research, using driving simulation, crash data, and naturalistic methods, has begun to shed light on the dangers of texting while driving. Perhaps because of the dangers, no published work has experimentally investigated the dangers of texti...

The efficacy of objective and subjective predictors of driving performance during sleep restriction and circadian misalignment.

PubMed

Kosmadopoulos, Anastasi; Sargent, Charli; Zhou, Xuan; Darwent, David; Matthews, Raymond W; Dawson, Drew; Roach, Gregory D

2017-02-01

Fatigue is a significant contributor to motor-vehicle accidents and fatalities. Shift workers are particularly susceptible to fatigue-related risks as they are often sleep-restricted and required to commute around the clock. Simple assays of performance could provide useful indications of risk in fatigue management, but their effectiveness may be influenced by changes in their sensitivity to sleep loss across the day. The aim of this study was to evaluate the sensitivity of several neurobehavioral and subjective tasks to sleep restriction (SR) at different circadian phases and their efficacy as predictors of performance during a simulated driving task. Thirty-two volunteers (M±SD; 22.8±2.9 years) were time-isolated for 13-days and participated in one of two 14-h forced desynchrony protocols with sleep opportunities equivalent to 8h/24h (control) or 4h/24h (SR). At regular intervals during wake periods, participants completed a simulated driving task, several neurobehavioral tasks, including the psychomotor vigilance task (PVT), and subjective ratings, including a self-assessment measure of ability to perform. Scores transformed into standardized units relative to baseline were folded into circadian phase bins based on core body temperature. Sleep dose and circadian phase effect sizes were derived via mixed models analyses. Predictors of driving were identified with regressions. Performance was most sensitive to sleep restriction around the circadian nadir. The effects of sleep restriction around the circadian nadir were larger for simulated driving and neurobehavioral tasks than for subjective ratings. Tasks did not significantly predict driving performance during the control condition or around the acrophase during the SR condition. The PVT and self-assessed ability were the best predictors of simulated driving across circadian phases during SR. These results show that simple performance measures and self-monitoring explain a large proportion of the variance in driving when fatigue-risk is high. Copyright © 2015 Elsevier Ltd. All rights reserved.

The influence of music on mental effort and driving performance.

PubMed

Ünal, Ayça Berfu; Steg, Linda; Epstude, Kai

2012-09-01

The current research examined the influence of loud music on driving performance, and whether mental effort mediated this effect. Participants (N=69) drove in a driving simulator either with or without listening to music. In order to test whether music would have similar effects on driving performance in different situations, we manipulated the simulated traffic environment such that the driving context consisted of both complex and monotonous driving situations. In addition, we systematically kept track of drivers' mental load by making the participants verbally report their mental effort at certain moments while driving. We found that listening to music increased mental effort while driving, irrespective of the driving situation being complex or monotonous, providing support to the general assumption that music can be a distracting auditory stimulus while driving. However, drivers who listened to music performed as well as the drivers who did not listen to music, indicating that music did not impair their driving performance. Importantly, the increases in mental effort while listening to music pointed out that drivers try to regulate their mental effort as a cognitive compensatory strategy to deal with task demands. Interestingly, we observed significant improvements in driving performance in two of the driving situations. It seems like mental effort might mediate the effect of music on driving performance in situations requiring sustained attention. Other process variables, such as arousal and boredom, should also be incorporated to study designs in order to reveal more on the nature of how music affects driving. Copyright © 2012 Elsevier Ltd. All rights reserved.

Driving Comparisons Between Young Adults with Autism Spectrum Disorder and Typical Development.

PubMed

Patrick, Kristina E; Hurewitz, Felicia; McCurdy, Mark D; Agate, Frederic Taylor; Daly, Brian P; Tarazi, Reem A; Chute, Douglas L; Schultheis, Maria T

2018-05-18

Many individuals with autism spectrum disorder (ASD) are reluctant to pursue driving because of concerns about their ability to drive safely. This study aimed to assess differences in simulated driving performance in young adults with ASD and typical development, examining relationships between driving performance and the level of experience (none, driver's permit, licensed) across increasingly difficult driving environments. Participants included 50 English-speaking young adults (16-26 years old) with ASD matched for sex, age, and licensure with 50 typically-developing (TD) peers. Participants completed a structured driving assessment using a virtual-reality simulator that included increasingly complex environmental demands. Differences in mean speed and speed and lane variability by diagnostic group and driving experience were analyzed using multilevel linear modeling. Young adults with ASD demonstrated increased variability in speed and lane positioning compared with controls, even during low demand tasks. When driving demands became more complex, group differences were moderated by driving experience such that licensed drivers with ASD drove similarly to TD licensed drivers for most tasks, whereas unlicensed drivers with ASD had more difficulty with speed and lane management than TD drivers. Findings suggest that young adults with ASD may have more difficulty with basic driving skills than peers, particularly in the early stages of driver training. Increased difficulty compared with peers increases as driving demands become more complex, suggesting that individuals with ASD may benefit from a slow and gradual approach to driver training. Future studies should evaluate predictors of driving performance, on-road driving, and ASD-specific driving interventions.

Next-day residual effects of hypnotics in DSM-IV primary insomnia: a driving simulator study with simultaneous electroencephalogram monitoring.

PubMed

Staner, Luc; Ertlé, Stéphane; Boeijinga, Peter; Rinaudo, Gilbert; Arnal, Marie Agnès; Muzet, Alain; Luthringer, Rémy

2005-10-01

Most studies that investigated the next-day residual effects of hypnotic drugs on daytime driving performances were performed on healthy subjects and after a single drug administration. In the present study, we further examine whether the results of these studies could be generalised to insomniac patients and after repeated drug administration. Single and repeated (7 day) doses of zolpidem (10 mg), zopiclone (7.5 mg), lormetazepam (1 mg) or placebo were administered at bedtime in a crossover design to 23 patients (9 men and 14 women aged 38.8+/-2.0 years) with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) primary insomnia. Driving tests were performed 9-11 h post-dose. Results showed that treatment effects were evidenced for subjective sleep, for driving abilities, and for electroencephalogram (EEG) recorded before (resting EEG) and during the driving simulation test (driving EEG). Compared to placebo, zopiclone increased the number of collisions and lormetazepam increased deviation from speed limit and deviation from absolute speed, whereas zolpidem did not differentiate from placebo on these analyses. EEG recordings showed that in contrast to zolpidem, lormetazepam and zopiclone induced typical benzodiazepine-like alterations, suggesting that next-day poor driving performance could relate to a prolonged central nervous system effect of these two hypnotics. The present results corroborate studies on healthy volunteers showing that residual effects of hypnotics increase with their half-lives. The results further suggest that drugs preserving physiological EEG rhythms before and during the driving simulation test 9-11 h post-dose, such as zolpidem, do not influence next-day driving abilities.

Interrater Reliability of the Power Mobility Road Test in the Virtual Reality-Based Simulator-2.

PubMed

Kamaraj, Deepan C; Dicianno, Brad E; Mahajan, Harshal P; Buhari, Alhaji M; Cooper, Rory A

2016-07-01

To assess interrater reliability of the Power Mobility Road Test (PMRT) when administered through the Virtual Reality-based SIMulator-version 2 (VRSIM-2). Within-subjects repeated-measures design. Participants interacted with VRSIM-2 through 2 display options (desktop monitor vs immersive virtual reality screens) using 2 control interfaces (roller system vs conventional movement-sensing joystick), providing 4 different driving scenarios (driving conditions 1-4). Participants performed 3 virtual driving sessions for each of the 2 display screens and 1 session through a real-world driving course (driving condition 5). The virtual PMRT was conducted in a simulated indoor office space, and an equivalent course was charted in an open space for the real-world assessment. After every change in driving condition, participants completed a self-reported workload assessment questionnaire, the Task Load Index, developed by the National Aeronautics and Space Administration. A convenience sample of electric-powered wheelchair (EPW) athletes (N=21) recruited at the 31st National Veterans Wheelchair Games. Not applicable. Total composite PMRT score. The PMRT had high interrater reliability (intraclass correlation coefficient [ICC]>.75) between the 2 raters in all 5 driving conditions. Post hoc analyses revealed that the reliability analyses had >80% power to detect high ICCs in driving conditions 1 and 4. The PMRT has high interrater reliability in conditions 1 and 4 and could be used to assess EPW driving performance virtually in VRSIM-2. However, further psychometric assessment is necessary to assess the feasibility of administering the PMRT using the different interfaces of VRSIM-2. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

FINAL REPORT INTEGRATED DM1200 MELTER TESTING OF BUBBLER CONFIGURATIONS USING HLW AZ-101 SIMULANTS VSL-04R4800-4 REV 0 10/5/04

DOE Office of Scientific and Technical Information (OSTI.GOV)

KRUGER AA; MATLACK KS; GONG W

2011-12-29

This report documents melter and off-gas performance results obtained on the DM1200 HLW Pilot Melter during processing of AZ-101 HLW simulants. The tests reported herein are a subset of six tests from a larger series of tests described in the Test Plan for the work; results from the other tests have been reported separately. The solids contents of the melter feeds were based on the WTP baseline value for the solids content of the feeds from pretreatment which changed during these tests from 20% to 15% undissolved solids resulting in tests conducted at two feed solids contents. Based on themore » results of earlier tests with single outlet 'J' bubblers, initial tests were performed with a total bubbling rate of 651 pm. The first set of tests (Tests 1A-1E) addressed the effects of skewing this total air flow rate back and forth between the two installed bubblers in comparison to a fixed equal division of flow between them. The second set of tests (2A-2D) addressed the effects of bubbler depth. Subsequently, as the location, type and number of bubbling outlets were varied, the optimum bubbling rate for each was determined. A third (3A-3C) and fourth (8A-8C) set of tests evaluated the effects of alternative bubbler designs with two gas outlets per bubbler instead of one by placing four bubblers in positions simulating multiple-outlet bubblers. Data from the simulated multiple outlet bubblers were used to design bubblers with two outlets for an additional set of tests (9A-9C). Test 9 was also used to determine the effect of small sugar additions to the feed on ruthenium volatility. Another set of tests (10A-10D) evaluated the effects on production rate of spiking the feed with chloride and sulfate. Variables held constant to the extent possible included melt temperature, plenum temperature, cold cap coverage, the waste simulant composition, and the target glass composition. The feed rate was increased to the point that a constant, essentially complete, cold cap was achieved, which was used as an indicator of a maximized feed rate for each test. The first day of each test was used to build the cold cap and decrease the plenum temperature. The remainder of each test was split into two- to six-day segments, each with a different bubbling rate, bubbler orientation, or feed concentration of chloride and sulfur.« less

Simulation and analysis of a model dinoflagellate predator-prey system

NASA Astrophysics Data System (ADS)

Mazzoleni, M. J.; Antonelli, T.; Coyne, K. J.; Rossi, L. F.

2015-12-01

This paper analyzes the dynamics of a model dinoflagellate predator-prey system and uses simulations to validate theoretical and experimental studies. A simple model for predator-prey interactions is derived by drawing upon analogies from chemical kinetics. This model is then modified to account for inefficiencies in predation. Simulation results are shown to closely match the model predictions. Additional simulations are then run which are based on experimental observations of predatory dinoflagellate behavior, and this study specifically investigates how the predatory dinoflagellate Karlodinium veneficum uses toxins to immobilize its prey and increase its feeding rate. These simulations account for complex dynamics that were not included in the basic models, and the results from these computational simulations closely match the experimentally observed predatory behavior of K. veneficum and reinforce the notion that predatory dinoflagellates utilize toxins to increase their feeding rate.

Application of a computer simulation model to migrating white-fronted geese in the Klamath Basin

USGS Publications Warehouse

Frederick, R.B.; Clark, William R.; Takekawa, John Y.; McCullough, Dale R.; Barrett, R.H.

1992-01-01

The Pacific greater white-fronted goose (Anser albifrons) population has declined precipitously over the past 20 years. Loss of wetland habitat in California wintering areas has had a significant effect on the population, so recovery of the population may depend on innovative management of the few remaining wetlands. A computer simulation model, REFMOD, was applied to greater white-fronted geese in the Klamath Basin, northern California, to investigate the importance of food availability and hunting disturbance to migrating and wintering populations. Time spent flying and feeding was simulated during fall and early winter, and the resulting energy expenditure was compared with energy consumed to calculate an overall energy balance. This energy balance and the ease with which waterfowl acquired needed food affected emigration rate, and thus, the waterfowl population level was directly tied to availability and distribution of food. The model validly described distances moved by geese from their Tule Lake Refuge roosting site (core) to feeding sites within the surrounding Klamath Basin arena, and exhibited a capability to simulate observed time spent feeding. Based on 25 stochastic simulations, greater white-fronted goose population dynamics were validly simulated over the fall and early-winter (P>0.8). When food was removed from the Tule Lake Refuge, simulated geese had to fly farther (P<0.0001) to find food, hastening emigration and resulting in a decline (P<0.05) in use of the Klamath Basin by geese. Although barley is normally abundant in the basin and is extensively used by geese, simulated elimination of barley in the arena did not cause a reduction in goose numbers (P>0.05). The elimination did cause an increase in the distance traveled to feed (P<0.05), but the availability of other foods in the basin (e.g., potatoes) was evidently sufficient to support the population. The elimination of hunting in the Klamath Basin, and the related decrease in disturbance of feeding birds, had little effect (P>0.05) on the distance traveled to feed or on goose numbers. A 10-fold increase in disturbance hastened emigration and reduced population levels (P<0.0001) during the season by about 30%; a 100-fold increase in disturbance reduced population levels (P<0.0001) by 85%. When goose immigration was increased to simulate an average peak population of approximately 500 000 geese, population levels remained high throughout the fall, indicating the Klamath Basin can sustain a population much larger than currently exists. This suggests food availability and disturbance levels in the Klamath Basin are not responsible for observed population declines during the last 2 decades. REFMOD can easily be used to evaluate the effects of other scenarios related to hunting regimes and food distribution and availability.

EMERGENCY BRAKING IN ADULTS VERSUS NOVICE TEEN DRIVERS: RESPONSE TO SIMULATED SUDDEN DRIVING EVENTS.

PubMed

Loeb, Helen S; Kandadai, Venk; McDonald, Catherine C; Winston, Flaura K

Motor vehicle crashes remain the leading cause of death in teens in the United States. Newly licensed drivers are the group most at risk for crashes. Their driving skills are very new, still very often untested, so that their ability to properly react in an emergency situation remains a research question. Since it is impossible to expose human subjects to critical life threatening driving scenarios, researchers have been increasingly using driving simulators to assess driving skills. This paper summarizes the results of a driving scenario in a study comparing the driving performance of novice teen drivers (n=21) 16-17 year olds with 90 days of provisional licensure with that of experienced adult drivers (n=17) 25-50 year olds with at least 5 years of PA licensure, at least 100 miles driven per week and no self-reported collisions in the previous 3 years. As part of a 30 to 35 simulated drive that encompassed the most common scenarios that result in serious crashes, participants were exposed to a sudden car event. As the participant drove on a suburban road, a car surged from a driveway hidden by a fence on the right side of the road. To avoid the crash, participants must hard brake, exhibiting dynamic control over both attentional and motor resources. The results showed strong differences between the experienced adult and novice teen drivers in the brake pressure applied. When placed in the same situation, the novice teens decelerated on average 50% less than the experienced adults (p<0.01).

EMERGENCY BRAKING IN ADULTS VERSUS NOVICE TEEN DRIVERS: RESPONSE TO SIMULATED SUDDEN DRIVING EVENTS

PubMed Central

Kandadai, Venk; McDonald, Catherine C.; Winston, Flaura K.

2015-01-01

Motor vehicle crashes remain the leading cause of death in teens in the United States. Newly licensed drivers are the group most at risk for crashes. Their driving skills are very new, still very often untested, so that their ability to properly react in an emergency situation remains a research question. Since it is impossible to expose human subjects to critical life threatening driving scenarios, researchers have been increasingly using driving simulators to assess driving skills. This paper summarizes the results of a driving scenario in a study comparing the driving performance of novice teen drivers (n=21) 16–17 year olds with 90 days of provisional licensure with that of experienced adult drivers (n=17) 25–50 year olds with at least 5 years of PA licensure, at least 100 miles driven per week and no self-reported collisions in the previous 3 years. As part of a 30 to 35 simulated drive that encompassed the most common scenarios that result in serious crashes, participants were exposed to a sudden car event. As the participant drove on a suburban road, a car surged from a driveway hidden by a fence on the right side of the road. To avoid the crash, participants must hard brake, exhibiting dynamic control over both attentional and motor resources. The results showed strong differences between the experienced adult and novice teen drivers in the brake pressure applied. When placed in the same situation, the novice teens decelerated on average 50% less than the experienced adults (p<0.01). PMID:26709330

Steering Control in a Low-Cost Driving Simulator: A Case for the Role of Virtual Vehicle Cab.

PubMed

Mecheri, Sami; Lobjois, Régis

2018-04-01

The aim of this study was to investigate steering control in a low-cost driving simulator with and without a virtual vehicle cab. In low-cost simulators, the lack of a vehicle cab denies driver access to vehicle width, which could affect steering control, insofar as locomotor adjustments are known to be based on action-scaled visual judgments of the environment. Two experiments were conducted in which steering control with and without a virtual vehicle cab was investigated in a within-subject design, using cornering and straight-lane-keeping tasks. Driving around curves without vehicle cab information made drivers deviate more from the lane center toward the inner edge in right (virtual cab = 4 ± 19 cm; no cab = 42 ± 28 cm; at the apex of the curve, p < .001) but not in left curves. More lateral deviation from the lane center toward the edge line was also found in driving without the virtual cab on straight roads (virtual cab = 21 ± 28 cm; no cab = 36 ± 27 cm; p < .001), whereas driving stability and presence ratings were not affected. In both experiments, the greater lateral deviation in the no-cab condition led to significantly more time driving off the lane. The findings strongly suggest that without cab information, participants underestimate the distance to the right edge of the car (in contrast to the left edge) and thus vehicle width. This produces considerable differences in the steering trajectory. Providing a virtual vehicle cab must be encouraged for more effectively capturing drivers' steering control in low-cost simulators.

Effects of dexamphetamine with and without alcohol on simulated driving.

PubMed

Simons, Ries; Martens, Marieke; Ramaekers, Jan; Krul, Arno; Klöpping-Ketelaars, Ineke; Skopp, Gisela

2012-08-01

In party circuits dexamphetamine is frequently used in combination with alcohol. It is hypothesized that co-administration of dexamphetamine to alcohol might reduce the sedative effects of alcohol, but may potentiate risk-taking behaviour. The study was aimed at assessing the effects of alcohol, dexamphetamine and the combination of both on simulated driving and cognitive performance. Eighteen subjects participated in a randomized, crossover, placebo-controlled study employing four conditions: 10 mg dexamphetamine, 0.8 g/kg alcohol, 10 mg dexamphetamine + 0.8 g/kg alcohol, and placebo. Fundamental driving skills and risk-taking behaviour were assessed in a driving simulator. Subjects also completed vigilance and divided attention tasks, and subjective ratings. Mean BAC levels during simulated driving were between 0.91‰ and 0.64‰. Subjects using alcohol showed a significantly larger mean standard deviation of lateral position and shorter accepted gap time and distance. Use of alcohol or dexamphetamine + alcohol was associated with a higher frequency of red light running and collisions than the dexamphetamine or placebo conditions. Performance of vigilance and divided attention tasks was significantly impaired in the alcohol condition and, to a lesser degree, in the dexamphetamine + alcohol condition. Single doses of 0.8 g/kg alcohol increased risk-taking behaviours and impaired tracking, attention and reaction time during a 3-h period after drinking when BACs declined from 0.9 to 0.2 mg/ml. The stimulatory effects of co-administration of dexamphetamine 10 mg were not sufficient to overcome the impairing effects of alcohol on skills related to driving.

A driving simulator study of driver performance on deceleration lanes.

PubMed

Calvi, A; Benedetto, A; De Blasiis, M R

2012-03-01

Deceleration lanes are important because they help drivers transition from high-speed lanes to low-speed ramps. Although they are designed to allow vehicles to depart the freeway safely and efficiently, many studies report high accident rates on exit ramps with the highest percentage of crashes taking place in deceleration lanes. This paper describes the results of a driving simulator study that focused on driving performance while approaching a divergence area and decelerating during the exiting maneuver. Three different traffic scenarios were simulated to analyze the influence of traffic volume on driving performance. Thirty drivers drove in the simulator in these scenarios while data on their lateral position, speed and deceleration were collected. Our results indicate there are considerable differences between the main assumptions of models generally used to design deceleration lanes and actual driving performance. In particular, diverging drivers begin to decelerate before arriving at the deceleration lane, causing interference with the main flow. Moreover, speeds recorded at the end of the deceleration lane exceed those for which the ramp's curves are designed; this creates risky driving conditions that could explain the high crash rates found in studies of exit ramps. Finally, statistical analyses demonstrate significant influences of traffic volume on some aspects of exiting drivers' performance: lower traffic volume results in elevated exiting speed and deceleration, and diverging drivers begin to decelerate earlier along the main lane when traffic volume is low. However, speeds at the end of the deceleration lane and the site of lane changing are not significantly influenced by traffic volume. Copyright © 2011 Elsevier Ltd. All rights reserved.

Detection of driver engagement in secondary tasks from observed naturalistic driving behavior.

PubMed

Ye, Mengqiu; Osman, Osama A; Ishak, Sherif; Hashemi, Bita

2017-09-01

Distracted driving has long been acknowledged as one of the leading causes of death or injury in roadway crashes. The focus of past research has been mainly on the impact of different causes of distraction on driving behavior. However, only a few studies attempted to address how some driving behavior attributes could be linked to the cause of distraction. In essence, this study takes advantage of the rich SHRP 2 Naturalistic Driving Study (NDS) database to develop a model for detecting the likelihood of a driver's involvement in secondary tasks from distinctive attributes of driving behavior. Five performance attributes, namely speed, longitudinal acceleration, lateral acceleration, yaw rate, and throttle position were used to describe the driving behavior. A model was developed for each of three selected secondary tasks: calling, texting, and passenger interaction. The models were developed using a supervised feed-forward Artificial Neural Network (ANN) architecture to account for the effect of inherent nonlinearity in the relationships between driving behavior and secondary tasks. The results show that the developed ANN models were able to detect the drivers' involvement in calling, texting, and passenger interaction with an overall accuracy of 99.5%, 98.1%, and 99.8%, respectively. These results show that the selected driving performance attributes were effective in detecting the associated secondary tasks with driving behavior. The results are very promising and the developed models could potentially be applied in crash investigations to resolve legal disputes in traffic accidents. Copyright © 2017 Elsevier Ltd. All rights reserved.

Attention and driving performance modulations due to anger state: Contribution of electroencephalographic data.

PubMed

Techer, Franck; Jallais, Christophe; Corson, Yves; Moreau, Fabien; Ndiaye, Daniel; Piechnick, Bruno; Fort, Alexandra

2017-01-01

Driver internal state, including emotion, can have negative impacts on road safety. Studies have shown that an anger state can provoke aggressive behavior and impair driving performance. Apart from driving, anger can also influence attentional processing and increase the benefits taken from auditory alerts. However, to our knowledge, no prior event-related potentials study assesses this impact on attention during simulated driving. Therefore, the aim of this study was to investigate the impact of anger on attentional processing and its consequences on driving performance. For this purpose, 33 participants completed a simulated driving scenario once in an anger state and once during a control session. Results indicated that anger impacted driving performance and attention, provoking an increase in lateral variations while reducing the amplitude of the visual N1 peak. The observed effects were discussed as a result of high arousal and mind-wandering associated with anger. This kind of physiological data may be used to monitor a driver's internal state and provide specific assistance corresponding to their current needs. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

INTEGRATED DM 1200 MELTER TESTING OF HLW C-106/AY-102 COMPOSITION USING BUBBLERS VSL-03R3800-1 REV 0 9/15/03

DOE Office of Scientific and Technical Information (OSTI.GOV)

KRUGER AA; MATLACK KS; GONG W

2011-12-29

This report documents melter and off-gas performance results obtained on the DM1200 HLW Pilot Melter during processing of simulated HLW C-106/AY-102 feed. The principal objectives of the DM1200 melter testing were to determine the achievable glass production rates for simulated HLW C-106/AY-102 feed; determine the effect of bubbling rate on production rate; characterize melter off-gas emissions; characterize the performance of the prototypical off-gas system components as well as their integrated performance; characterize the feed, glass product, and off-gas effluents; and to perform pre- and post test inspections of system components.

Texas-specific drive cycles and idle emissions rates for using with EPA's MOVES model : final report.

DOT National Transportation Integrated Search

2014-05-01

The U.S. Environmental Protection Agencys (EPA) newest emissions model, MOtor Vehicle : Emission Simulator (MOVES), uses a disaggregate approach that enables the users of the model to create : and use local drive schedules (drive cycles) in order ...

Dual-task effects of simulated lane navigation and story recall in older adults with and without memory impairment

PubMed Central

Cook, Sarah E.; Sisco, Shannon M.; Marsiske, Michael

2013-01-01

While driving is a complex task, it becomes relatively automatic over time although unfamiliar situations require increased cognitive effort. Much research has examined driving risk in cognitively impaired elders and found little effect. This study assessed whether mildly memory impaired elders made disproportionate errors in driving or story recall, under simultaneous simulated driving and story recall. Forty-six healthy (61% women; mean age = 76.4) and 15 memory impaired (66% women, mean age = 79.4) elders participated. Cognitive status was determined by neuropsychological performance. Results showed that during dual-task conditions, participants stayed in lane more, and recalled stories more poorly, than when they did the tasks separately. Follow-up analysis revealed that verbatim recall, in particular, was reduced while driving for healthy participants. While memory impaired participants performed more poorly than healthy controls on both tasks, cognitive status was not associated with greater dual-task costs when driving and story recall were combined. PMID:23043546

Multi-mode energy management strategy for fuel cell electric vehicles based on driving pattern identification using learning vector quantization neural network algorithm

NASA Astrophysics Data System (ADS)

Song, Ke; Li, Feiqiang; Hu, Xiao; He, Lin; Niu, Wenxu; Lu, Sihao; Zhang, Tong

2018-06-01

The development of fuel cell electric vehicles can to a certain extent alleviate worldwide energy and environmental issues. While a single energy management strategy cannot meet the complex road conditions of an actual vehicle, this article proposes a multi-mode energy management strategy for electric vehicles with a fuel cell range extender based on driving condition recognition technology, which contains a patterns recognizer and a multi-mode energy management controller. This paper introduces a learning vector quantization (LVQ) neural network to design the driving patterns recognizer according to a vehicle's driving information. This multi-mode strategy can automatically switch to the genetic algorithm optimized thermostat strategy under specific driving conditions in the light of the differences in condition recognition results. Simulation experiments were carried out based on the model's validity verification using a dynamometer test bench. Simulation results show that the proposed strategy can obtain better economic performance than the single-mode thermostat strategy under dynamic driving conditions.

Dual-task effects of simulated lane navigation and story recall in older adults with and without memory impairment.

PubMed

Cook, Sarah E; Sisco, Shannon M; Marsiske, Michael

2013-01-01

While driving is a complex task, it becomes relatively automatic over time although unfamiliar situations require increased cognitive effort. Much research has examined driving risk in cognitively impaired elders and found little effect. This study assessed whether mildly memory impaired elders made disproportionate errors in driving or story recall, under simultaneous simulated driving and story recall. Forty-six healthy (61% women; mean age = 76.4) and 15 memory impaired (66% women, mean age = 79.4) elders participated. Cognitive status was determined by neuropsychological performance. Results showed that during dual-task conditions, participants stayed in lane more, and recalled stories more poorly, than when they did the tasks separately. Follow-up analysis revealed that verbatim recall, in particular, was reduced while driving for healthy participants. While memory impaired participants performed more poorly than healthy controls on both tasks, cognitive status was not associated with greater dual-task costs when driving and story recall were combined.

Drive and protection circuit for converter module of cascaded H-bridge STATCOM

NASA Astrophysics Data System (ADS)

Wang, Xuan; Yuan, Hongliang; Wang, Xiaoxing; Wang, Shuai; Fu, Yongsheng

2018-04-01

Drive and protection circuit is an important part of power electronics, which is related to safe and stable operation issues in the power electronics. The drive and protection circuit is designed for the cascaded H-bridge STATCOM. This circuit can realize flexible dead-time setting, operation status self-detection, fault priority protection and detailed fault status uploading. It can help to improve the reliability of STATCOM's operation. Finally, the proposed circuit is tested and analyzed by power electronic simulation software PSPICE (Simulation Program with IC Emphasis) and a series of experiments. Further studies showed that the proposed circuit can realize drive and control of H-bridge circuit, meanwhile it also can realize fast processing faults and have advantage of high reliability.

Effects of advertising billboards during simulated driving.

PubMed

Edquist, Jessica; Horberry, Tim; Hosking, Simon; Johnston, Ian

2011-05-01

There is currently a great deal of interest in the problem of driver distraction. Most research focuses on distractions from inside the vehicle, but drivers can also be distracted by objects outside the vehicle. Major roads are increasingly becoming sites for advertising billboards, and there is little research on the potential effects of this advertising on driving performance. The driving simulator experiment presented here examines the effects of billboards on drivers, including older and inexperienced drivers who may be more vulnerable to distractions. The presence of billboards changed drivers' patterns of visual attention, increased the amount of time needed for drivers to respond to road signs, and increased the number of errors in this driving task. Copyright © 2010 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Three-dimensional computer simulations of feeding behaviour in red and giant pandas relate skull biomechanics with dietary niche partitioning.

PubMed

Figueirido, Borja; Tseng, Zhijie Jack; Serrano-Alarcón, Francisco J; Martín-Serra, Alberto; Pastor, Juan F

2014-01-01

The red (Ailurus fulgens) and giant (Ailuropoda melanoleuca) pandas are mammalian carnivores convergently adapted to a bamboo feeding diet. However, whereas Ailurus forages almost entirely on younger leaves, fruits and tender trunks, Ailuropoda relies more on trunks and stems. Such difference in foraging mode is considered a strategy for resource partitioning where they are sympatric. Here, we use finite-element analysis to test for mechanical differences and similarities in skull performance between Ailurus and Ailuropoda related to diet. Feeding simulations suggest that the two panda species have similar ranges of mechanical efficiency and strain energy profiles across the dentition, reflecting their durophagous diet. However, the stress distributions and peaks in the skulls of Ailurus and Ailuropoda are remarkably different for biting at all tooth locations. Although the skull of Ailuropoda is capable of resisting higher stresses than the skull of Ailurus, the latter is able to distribute stresses more evenly throughout the skull. These differences in skull biomechanics reflect their distinct bamboo feeding preferences. Ailurus uses repetitive chewing in an extended mastication to feed on soft leaves, and Ailuropoda exhibits shorter and more discrete periods of chomp-and-swallow feeding to break down hard bamboo trunks.

Near-term hybrid vehicle program, phase 1. Appendix B: Design trade-off studies. [various hybrid/electric power train configurations and electrical and mechanical drive-line components

NASA Technical Reports Server (NTRS)

1979-01-01

The relative attractiveness of various hybrid/electric power train configurations and electrical and mechanical drive-line components was studied. The initial screening was concerned primarily with total vehicle weight and economic factors and identified the hybrid power train combinations which warranted detailed evaluation over various driving cycles. This was done using a second-by-second vehicle simulation program which permitted the calculations of fuel economy, electricity usage, and emissions as a function of distance traveled in urban and highway driving. Power train arrangement possibilities were examined in terms of their effect on vehicle handling, safety, serviceability, and passenger comfort. A dc electric drive system utilizing a separately excited motor with field control and battery switching was selected for the near term hybrid vehicle. Hybrid vehicle simulations showed that for the first 30 mi (the electric range of the vehicle) in urban driving, the fuel economy was 80 mpg using a gasoline engine and 100 mpg using a diesel engine. In urban driving the hybrid would save about 75% of the fuel used by the conventional vehicle and in combined urban/highway driving the fuel saving is about 50%.

Systems, compositions, and methods for fluid purification

DOEpatents

Ho, W.S. Winston; Verweij, Hendrik; Shqau, Krenar; Ramasubranian, Kartik

2015-12-22

Disclosed herein are membranes comprising a substrate, a support layer, and a selective layer. In some embodiments the membrane may further comprise a permeable layer. Methods of forming membranes are also disclosed comprising forming a support layer on a substrate, removing adsorbed species from the support layer, preparing a solution containing inorganic materials of a selective layer, contacting the support layer with the solution, drying the membrane, and exposing the membrane to rapid thermal processing. Also disclosed are methods of fluid purification comprising providing a membrane having a feed side and a permeable side, passing a fluid mixture across the feed side of the membrane, providing a driving force for transmembrane permeation, removing from the permeate side a permeate stream enriched in a purified fluid, and withdrawing from the feed side a fluid that is depleted in a purified fluid.

Coplanar UHF RFID tag antenna with U-shaped inductively coupled feed for metallic applications.

PubMed

Salman, Karrar Naji; Ismail, Alyani; Raja Abdullah, Raja Syamsul Azmir; Saeedi, Tale

2017-01-01

In this paper, we present a novel compact, coplanar, tag antenna design for metallic objects. Electrically small antenna has designed for a UHF RFID (860-960 MHz) based on a proximity-coupled feed through. Furthermore, two symmetrical Via-loaded coplanar grounds fed by a U-shaped inductively coupled feed through an embedded transmission line. This configuration results in an antenna with dimensions of 31 × 19.5 × 3.065 mm3 at 915 MHz, and the total gain for the antenna is 0.12 dBi. The Via-loaded coplanar and U-shaped inductively coupled feeds allow the antenna to provide flexible tuning in terms of antenna impedance. In addition, a figure of merit is applied for the proposed tag antenna, and the results are presented. The read range is measured to be 4.2 m, which is very close to simulated values. This antenna measurement shows very good agreement with simulations.

Detecting Driver Mental Fatigue Based on EEG Alpha Power Changes during Simulated Driving.

PubMed

Gharagozlou, Faramarz; Nasl Saraji, Gebraeil; Mazloumi, Adel; Nahvi, Ali; Motie Nasrabadi, Ali; Rahimi Foroushani, Abbas; Arab Kheradmand, Ali; Ashouri, Mohammadreza; Samavati, Mehdi

2015-12-01

Driver fatigue is one of the major implications in transportation safety and accounted for up to 40% of road accidents. This study aimed to analyze the EEG alpha power changes in partially sleep-deprived drivers while performing a simulated driving task. Twelve healthy male car drivers participated in an overnight study. Continuous EEG and EOG records were taken during driving on a virtual reality simulator on a monotonous road. Simultaneously, video recordings from the driver face and behavior were performed in lateral and front views and rated by two trained observers. Moreover, the subjective self-assessment of fatigue was implemented in every 10-min interval during the driving using Fatigue Visual Analog Scale (F-VAS). Power spectrum density and fast Fourier transform (FFT) were used to determine the absolute and relative alpha powers in the initial and final 10 minutes of driving. The findings showed a significant increase in the absolute alpha power (P = 0.006) as well as F-VAS scores during the final section of driving (P = 0.001). Meanwhile, video ratings were consistent with subjective self-assessment of fatigue. The increase in alpha power in the final section of driving indicates the decrease in the level of alertness and attention and the onset of fatigue, which was consistent with F-VAS and video ratings. The study suggested that variations in alpha power could be a good indicator for driver mental fatigue, but for using as a countermeasure device needed further investigations.

Driving behavior recognition using EEG data from a simulated car-following experiment.

PubMed

Yang, Liu; Ma, Rui; Zhang, H Michael; Guan, Wei; Jiang, Shixiong

2018-07-01

Driving behavior recognition is the foundation of driver assistance systems, with potential applications in automated driving systems. Most prevailing studies have used subjective questionnaire data and objective driving data to classify driving behaviors, while few studies have used physiological signals such as electroencephalography (EEG) to gather data. To bridge this gap, this paper proposes a two-layer learning method for driving behavior recognition using EEG data. A simulated car-following driving experiment was designed and conducted to simultaneously collect data on the driving behaviors and EEG data of drivers. The proposed learning method consists of two layers. In Layer I, two-dimensional driving behavior features representing driving style and stability were selected and extracted from raw driving behavior data using K-means and support vector machine recursive feature elimination. Five groups of driving behaviors were classified based on these two-dimensional driving behavior features. In Layer II, the classification results from Layer I were utilized as inputs to generate a k-Nearest-Neighbor classifier identifying driving behavior groups using EEG data. Using independent component analysis, a fast Fourier transformation, and linear discriminant analysis sequentially, the raw EEG signals were processed to extract two core EEG features. Classifier performance was enhanced using the adaptive synthetic sampling approach. A leave-one-subject-out cross validation was conducted. The results showed that the average classification accuracy for all tested traffic states was 69.5% and the highest accuracy reached 83.5%, suggesting a significant correlation between EEG patterns and car-following behavior. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of different blood alcohol concentrations and post-alcohol impairment on driving behavior and task performance.

PubMed

Liu, Yung-Ching; Ho, Chin Heng

2010-08-01

A study using simulator methodology was conducted to investigate the effects of (1) different blood alcohol concentrations (BAC) of 0, 0.05, 0.08, and 0.10 percent and (2) post-alcohol impairment (where BAC approximately 0%) on driving behavior and subsidiary cognitive task performance. Two driving sessions were investigated, that is, drunk driving and post-alcohol driving, with each requiring approximately 20 min of driving. In addition to driving safely, participants were instructed to perform the critical flicker fusion (CFF) test and completed the NASA-TLX mental workload questionnaire. Eight licensed drivers (6 males, 2 females) participated in this 2 (road complexities) x 2 (simulated driving sessions) x 4 (levels of BAC) within-subjects experiment. The study revealed that higher BAC levels were associated with lower performing driving behavior. The driver's mental workload reached the highest values in the post-alcohol session. In terms of tasks involving divided attention, the traffic sign distance estimation showed significant deterioration with increased BAC levels. The relationship between drunk-driving behavior and alcohol dosage was supported in this study. Noticeably, no significant difference was found between drunk driving and post-alcohol driving, indicating that even in the post-alcohol situation, the impairment still remained significant enough to jeopardize traffic safety as much as it does in the case of drunk driving. In real-life situations, adopting a rest-time strategy to avoid post-alcohol impairment effects may not be the most appropriate solution by drivers; rather, drivers should be given some tests to verify the probability of post-alcohol effects on driving.

Are we using the right fuel to drive hydrological models? A climate impact study in the Upper Blue Nile

NASA Astrophysics Data System (ADS)

Liersch, Stefan; Tecklenburg, Julia; Rust, Henning; Dobler, Andreas; Fischer, Madlen; Kruschke, Tim; Koch, Hagen; Fokko Hattermann, Fred

2018-04-01

Climate simulations are the fuel to drive hydrological models that are used to assess the impacts of climate change and variability on hydrological parameters, such as river discharges, soil moisture, and evapotranspiration. Unlike with cars, where we know which fuel the engine requires, we never know in advance what unexpected side effects might be caused by the fuel we feed our models with. Sometimes we increase the fuel's octane number (bias correction) to achieve better performance and find out that the model behaves differently but not always as was expected or desired. This study investigates the impacts of projected climate change on the hydrology of the Upper Blue Nile catchment using two model ensembles consisting of five global CMIP5 Earth system models and 10 regional climate models (CORDEX Africa). WATCH forcing data were used to calibrate an eco-hydrological model and to bias-correct both model ensembles using slightly differing approaches. On the one hand it was found that the bias correction methods considerably improved the performance of average rainfall characteristics in the reference period (1970-1999) in most of the cases. This also holds true for non-extreme discharge conditions between Q20 and Q80. On the other hand, bias-corrected simulations tend to overemphasize magnitudes of projected change signals and extremes. A general weakness of both uncorrected and bias-corrected simulations is the rather poor representation of high and low flows and their extremes, which were often deteriorated by bias correction. This inaccuracy is a crucial deficiency for regional impact studies dealing with water management issues and it is therefore important to analyse model performance and characteristics and the effect of bias correction, and eventually to exclude some climate models from the ensemble. However, the multi-model means of all ensembles project increasing average annual discharges in the Upper Blue Nile catchment and a shift in seasonal patterns, with decreasing discharges in June and July and increasing discharges from August to November.

Turbine engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greer, D.

1988-02-16

In a turbine propulsion engine, an elongated motor is described including a power means and having a drive shaft projecting therefrom. A first compressor includes an elongated rotatable first casing coaxially mounted upon the motor having a fuel inlet for pressure feeding of fuel lengthwise of the first compressor. A second compressor includes a casing coaxially mounted upon and along the first compressor casing secured to the motor having an air inlet at its forward end for feeding high velocity compressed air lengthwise of the second compressor casing. An intermediate diverging casing at one end is peripherally connected to themore » second compressor casing having inner and outer diffusor chambers communicating respectively with the compressor for receiving high velocity vaporized fuel and compressed air. A turbine casing at one end is peripherally connected to the intermediate casing and at its other end having a converging exhaust outlet. An elongated combustion chamber of circular cross-section rotatably mounted and spaced within and journaled upon the turbine casing; an engine shaft extending axially through the combustion chamber, journaled upon the turbine casing and axially connected to the drive shaft.« less

Dynamic Simulation Research on Chain Drive Mechanism of Corn Seeder Based on ADAMS

NASA Astrophysics Data System (ADS)

Wang, Y. B.; Jia, H. P.

2017-12-01

In order to reduce the damage to the chain and improve the seeding quality of the seeding machine, the corn seeder has the characteristics of the seeding quality and some technical indexes in the work of the corn seeding machine. The dynamic analysis of the chain drive mechanism is carried out by using the dynamic virtual prototype. In this paper, the speed of the corn planter is 5km/h, and the speed of the simulated knuckle is 0.1~0.9s. The velocity is 0.12m/s, which is equal to the chain speed when the seeder is running normally. Of the dynamic simulation of the movement and the actual situation is basically consistent with the apparent speed of the drive wheel has changed the acceleration and additional dynamic load, the chain drive has a very serious damage, and the maximum load value of 47.28N, in order to reduce the damage to the chain, As far as possible so that the sowing machine in the work to maintain a reasonable uniform speed, to avoid a greater acceleration, the corn sowing machine drive the design of a certain reference.

Demonstration of Fuel Hot-Spot Pressure in Excess of 50 Gbar for Direct-Drive, Layered Deuterium-Tritium Implosions on OMEGA

NASA Astrophysics Data System (ADS)

Regan, S. P.; Goncharov, V. N.; Igumenshchev, I. V.; Sangster, T. C.; Betti, R.; Bose, A.; Boehly, T. R.; Bonino, M. J.; Campbell, E. M.; Cao, D.; Collins, T. J. B.; Craxton, R. S.; Davis, A. K.; Delettrez, J. A.; Edgell, D. H.; Epstein, R.; Forrest, C. J.; Frenje, J. A.; Froula, D. H.; Gatu Johnson, M.; Glebov, V. Yu.; Harding, D. R.; Hohenberger, M.; Hu, S. X.; Jacobs-Perkins, D.; Janezic, R.; Karasik, M.; Keck, R. L.; Kelly, J. H.; Kessler, T. J.; Knauer, J. P.; Kosc, T. Z.; Loucks, S. J.; Marozas, J. A.; Marshall, F. J.; McCrory, R. L.; McKenty, P. W.; Meyerhofer, D. D.; Michel, D. T.; Myatt, J. F.; Obenschain, S. P.; Petrasso, R. D.; Radha, P. B.; Rice, B.; Rosenberg, M. J.; Schmitt, A. J.; Schmitt, M. J.; Seka, W.; Shmayda, W. T.; Shoup, M. J.; Shvydky, A.; Skupsky, S.; Solodov, A. A.; Stoeckl, C.; Theobald, W.; Ulreich, J.; Wittman, M. D.; Woo, K. M.; Yaakobi, B.; Zuegel, J. D.

2016-07-01

A record fuel hot-spot pressure Phs=56 ±7 Gbar was inferred from x-ray and nuclear diagnostics for direct-drive inertial confinement fusion cryogenic, layered deuterium-tritium implosions on the 60-beam, 30-kJ, 351-nm OMEGA Laser System. When hydrodynamically scaled to the energy of the National Ignition Facility, these implosions achieved a Lawson parameter ˜60 % of the value required for ignition [A. Bose et al., Phys. Rev. E 93, LM15119ER (2016)], similar to indirect-drive implosions [R. Betti et al., Phys. Rev. Lett. 114, 255003 (2015)], and nearly half of the direct-drive ignition-threshold pressure. Relative to symmetric, one-dimensional simulations, the inferred hot-spot pressure is approximately 40% lower. Three-dimensional simulations suggest that low-mode distortion of the hot spot seeded by laser-drive nonuniformity and target-positioning error reduces target performance.

Demonstration of fuel hot-spot pressure in excess of 50 Gbar for direct-drive, layered deuterium-tritium implosions on OMEGA

DOE PAGES

Regan, S. P.; Goncharov, V. N.; Igumenshchev, I. V.; ...

2016-07-07

A record fuel hot-spot pressure P hs = 56±7 Gbar was inferred from x-ray and nuclear diagnostics for direct-drive inertial confinement fusion cryogenic, layered deuterium–tritium implosions on the 60-beam, 30-kJ, 351-nm OMEGA Laser System. When hydrodynamically scaled to the energy of the National Ignition Facility (NIF), these implosions achieved a Lawson parameter ~60% of the value required for ignition [A. Bose et al., Phys. Rev. E (in press)], similar to indirect-drive implosions [R. Betti et al., Phys. Rev. Lett. 114, 255003 (2015)], and nearly half of the direct-drive ignition-threshold pressure. Relative to symmetric, one-dimensional simulations, the inferred hot-spot pressure ismore » ~40% lower. Furthermore, three-dimensional simulations suggest that low-mode distortion of the hot spot seeded by laser-drive nonuniformity and target-positioning error reduces target performance.« less

Demonstration of fuel hot-spot pressure in excess of 50 Gbar for direct-drive, layered deuterium-tritium implosions on OMEGA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Regan, S. P.; Goncharov, V. N.; Igumenshchev, I. V.

A record fuel hot-spot pressure P hs = 56±7 Gbar was inferred from x-ray and nuclear diagnostics for direct-drive inertial confinement fusion cryogenic, layered deuterium–tritium implosions on the 60-beam, 30-kJ, 351-nm OMEGA Laser System. When hydrodynamically scaled to the energy of the National Ignition Facility (NIF), these implosions achieved a Lawson parameter ~60% of the value required for ignition [A. Bose et al., Phys. Rev. E (in press)], similar to indirect-drive implosions [R. Betti et al., Phys. Rev. Lett. 114, 255003 (2015)], and nearly half of the direct-drive ignition-threshold pressure. Relative to symmetric, one-dimensional simulations, the inferred hot-spot pressure ismore » ~40% lower. Furthermore, three-dimensional simulations suggest that low-mode distortion of the hot spot seeded by laser-drive nonuniformity and target-positioning error reduces target performance.« less

Research on Performance of Wire-controlled Hydraulic Steering System Based on Four-wheel Steering

NASA Astrophysics Data System (ADS)

Tao, P.; Jin, X. H.

2018-05-01

In this paper, the steering stability and control strategy of forklift are put forward. Drive based on yawing moment distribution of rotary torque coordination control method, through analyzing the linear two degree of freedom model of forklift truck, forklift yawing angular velocity and mass center side-slip Angle of expectations, as the control target parameters system, using fuzzy controller output driving forklift steering the yawing moment, to drive rotary torque distribution, make the forklift truck to drive horizontal pendulum angular velocity and side-slip Angle tracking reference model very well. In this paper, the lateral stability control system were designed, the joint simulation in MATLAB/Simulink, the simulation results show that under the different partial load, the control system can effectively to control side forklift lateral stability, enhanced the forklift driving safety, for the side forklift steering stability study provides a theoretical basis.

Translating cognitive neuroscience to the driver’s operational environment: a neuroergonomics approach

PubMed Central

Lees, Monica N.; Cosman, Joshua D.; Lee, John D.; Rizzo, Matthew; Fricke, Nicola

2012-01-01

Neuroergonomics provides a multidisciplinary translational approach that merges elements of neuroscience, human factors, cognitive psychology, and ergonomics to study brain structure and function in everyday environments. Driving safety, particularly that of older drivers with cognitive impairments, is a fruitful application domain for neuroergonomics. Driving makes demands on multiple cognitive processes that are often studied in isolation and so presents a useful challenge in generalizing findings from controlled laboratory tasks to predict safety outcomes. Neurology and the cognitive sciences help explain the mechanisms of cognitive breakdowns that undermine driving safety. Ergonomics complements this explanation with the tools for systematically exploring the various layers of complexity that define the activity of driving. A variety of tools, such as part task simulators, driving simulators, and instrumented vehicles provide a window into cognition in the natural settings needed to assess the generalizability of laboratory findings and can provide an array of potential interventions to increase safety. PMID:21291157

A Traction Control Strategy with an Efficiency Model in a Distributed Driving Electric Vehicle

PubMed Central

Lin, Cheng

2014-01-01

Both active safety and fuel economy are important issues for vehicles. This paper focuses on a traction control strategy with an efficiency model in a distributed driving electric vehicle. In emergency situation, a sliding mode control algorithm was employed to achieve antislip control through keeping the wheels' slip ratios below 20%. For general longitudinal driving cases, an efficiency model aiming at improving the fuel economy was built through an offline optimization stream within the two-dimensional design space composed of the acceleration pedal signal and the vehicle speed. The sliding mode control strategy for the joint roads and the efficiency model for the typical drive cycles were simulated. Simulation results show that the proposed driving control approach has the potential to apply to different road surfaces. It keeps the wheels' slip ratios within the stable zone and improves the fuel economy on the premise of tracking the driver's intention. PMID:25197697

A traction control strategy with an efficiency model in a distributed driving electric vehicle.

PubMed

Lin, Cheng; Cheng, Xingqun

2014-01-01

Both active safety and fuel economy are important issues for vehicles. This paper focuses on a traction control strategy with an efficiency model in a distributed driving electric vehicle. In emergency situation, a sliding mode control algorithm was employed to achieve antislip control through keeping the wheels' slip ratios below 20%. For general longitudinal driving cases, an efficiency model aiming at improving the fuel economy was built through an offline optimization stream within the two-dimensional design space composed of the acceleration pedal signal and the vehicle speed. The sliding mode control strategy for the joint roads and the efficiency model for the typical drive cycles were simulated. Simulation results show that the proposed driving control approach has the potential to apply to different road surfaces. It keeps the wheels' slip ratios within the stable zone and improves the fuel economy on the premise of tracking the driver's intention.

Classifying Drivers' Cognitive Load Using EEG Signals.

PubMed

Barua, Shaibal; Ahmed, Mobyen Uddin; Begum, Shahina

2017-01-01

A growing traffic safety issue is the effect of cognitive loading activities on traffic safety and driving performance. To monitor drivers' mental state, understanding cognitive load is important since while driving, performing cognitively loading secondary tasks, for example talking on the phone, can affect the performance in the primary task, i.e. driving. Electroencephalography (EEG) is one of the reliable measures of cognitive load that can detect the changes in instantaneous load and effect of cognitively loading secondary task. In this driving simulator study, 1-back task is carried out while the driver performs three different simulated driving scenarios. This paper presents an EEG based approach to classify a drivers' level of cognitive load using Case-Based Reasoning (CBR). The results show that for each individual scenario as well as using data combined from the different scenarios, CBR based system achieved approximately over 70% of classification accuracy.

Assessing the Effectiveness of Increased FIO2for Enhancing Driver's Activation State Using Simulated Monotonous Driving.

PubMed

Yamakoshi, T; Yamakoshi, K; Nogawa, M; Sawada, Y; Rolfe, P; Kusakabe, M

2005-01-01

Lowering of what we term a driver's Activation State (AS) during monotonous driving conditions may increase the risk of an accident. To develop an in-car environment that allows active driving - "Biofee dforward System" - we have investigated the effects of applying a stimulus of increased inspired oxygen fraction (FIO2) supply on a driver's AS, using simulated monotonous driving. We used our previously substantiated index of As derived from beat-by-beat blood pressure (BP) response following an electrical stimulus. We have made physiological measurements including BP and found that the increased FIO2stimulus is effective in enhancing the AS. This finding was also confirmed in terms of the autonomic activity balance as well as the lengthening in time for active, safer, driving.

Supertaskers: Profiles in extraordinary multitasking ability.

PubMed

Watson, Jason M; Strayer, David L

2010-08-01

Theory suggests that driving should be impaired for any motorist who is concurrently talking on a cell phone. But is everybody impaired by this dual-task combination? We tested 200 participants in a high-fidelity driving simulator in both single- and dual-task conditions. The dual task involved driving while performing a demanding auditory version of the operation span (OSPAN) task. Whereas the vast majority of participants showed significant performance decrements in dual-task conditions (compared with single-task conditions for either driving or OSPAN tasks), 2.5% of the sample showed absolutely no performance decrements with respect to performing single and dual tasks. In single-task conditions, these "supertaskers" scored in the top quartile on all dependent measures associated with driving and OSPAN tasks, and Monte Carlo simulations indicated that the frequency of supertaskers was significantly greater than chance. These individual differences help to sharpen our theoretical understanding of attention and cognitive control in naturalistic settings.

Drivers who self-estimate lower blood alcohol concentrations are riskier drivers after drinking.

PubMed

Laude, Jennifer R; Fillmore, Mark T

2016-04-01

Alcohol increases the tendency for risky driving in some individuals but not others. Little is known about the factors underlying this individual difference. Studies find that those who underestimate their blood alcohol concentration (BAC) following a dose of alcohol tend to be more impulsive and report greater willingness to drive after drinking than those who estimate their BACs to be greater than their actual BAC. BAC underestimation could contribute to risky driving behavior following alcohol as such drivers might perceive little impairment in their driving ability and thus no need for caution. This study was designed to test the relationship between drivers' BAC estimations following a dose of alcohol or a placebo and the degree of risky driving they displayed during a simulated driving test. Forty adult drivers performed a simulated driving test and estimated their blood alcohol concentration after receiving a dose of alcohol (0.65 g/kg for men and 0.56 g/kg for women) or a placebo. Alcohol increased risk-taking and impaired driving skill. Those who estimated their BAC to be lower were the riskiest drivers following both alcohol and placebo. The tendency to estimate lower BACs could support a series of high-risk decisions, regardless of one's actual BAC. This could include the decision to drive after drinking.

Driving performance and driver discomfort in an elevated and standard driving position during a driving simulation.

PubMed

Smith, Jordan; Mansfield, Neil; Gyi, Diane; Pagett, Mark; Bateman, Bob

2015-07-01

The primary purposes of a vehicle driver's seat, is to allow them to complete the driving task comfortably and safely. Within each class of vehicle (e.g. passenger, commercial, industrial, agricultural), there is an expected driving position to which a vehicle cabin is designed. This paper reports a study that compares two driving positions, in relation to Light Commercial Vehicles (LCVs), in terms of driver performance and driver discomfort. In the 'elevated' driving position, the seat is higher than usually used in road vehicles; this is compared to a standard driving position replicating the layout for a commercially available vehicle. It is shown that for a sample of 12 drivers, the elevated position did not, in general, show more discomfort than the standard position over a 60 min driving simulation, although discomfort increased with duration. There were no adverse effects shown for emergency stop reaction time or for driver headway for the elevated posture compared to the standard posture. The only body part that showed greater discomfort for the elevated posture compared to the standard posture was the right ankle. A second experiment confirmed that for 12 subjects, a higher pedal stiffness eliminated the ankle discomfort problem. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Simulation of Non-Acoustic Combustion Instability in a Hybrid Rocket Motor

NASA Technical Reports Server (NTRS)

Rocker, Marvin

1999-01-01

A transient model of a hybrid motor was formulated to study the cause and elimination of non-acoustic combustion instability. The transient model was used to simulate four key tests out of a series of seventeen hybrid motor tests conducted by Thiokol, Rocketdyne and Martin Marietta at NASA/Marshall Space Flight Center (NASAIMSFC). These tests were performed under the Hybrid Propulsion Technology for Launch Vehicle Boosters (HPTLVB) program. The first test resulted in stable combustion. The second test resulted in large-amplitude, 6.5 Hz chamber pressure oscillations that gradually damped away by the end of the test. The third test resulted in large-amplitude, 7.5 Hz chamber pressure oscillations that were sustained throughout the test. The seventh test resulted in the elimination of combustion instability with the installation of an orifice immediately upstream of the injector. The formulation and implementation of the model are the scope of this presentation. The current model is an independent continuation of modeling presented previously by joint Thiokol-Rocketdyne collaborators Boardman, Hawkins, Wassom, and Claflin. The previous model simulated an unstable IR&D hybrid motor test performed by Thiokol. There was very good agreement between the model and the test data. Like the previous model, the current model was developed using Matrix-x simulation software. However, the tests performed at NASA/MSFC under the HPTLVB program were actually simulated. In the current model, the hybrid motor consisting of the liquid oxygen (LOX) injector, the multi-port solid fuel grain and the nozzle was simulated. Also, simulated in the model was the LOX feed system consisting of the tank, venturi, valve and feed lines. All components of the hybrid motor and LOX feed system are treated by a lumped-parameter approach. Agreement between the results of the transient model and the actual test data was very good. This agreement between simulated and actual test data indicated that the combustion instability in the hybrid motor was due to two causes. The first cause was a LOX feed system of insufficient stiffness. The second cause was a LOX injector with an impedance or pressure drop that was too low to provide damping against the feed system oscillations. Also, it was discovered that testing with a new grain of solid fuel sustained the combustion instability. However, testing with a used grain of solid fuel caused the combustion instability to gradually decay.

Simulation of Non-Acoustic Combustion Instability in a Hybrid Rocket Motor

NASA Technical Reports Server (NTRS)

Rocker, Marvin

1999-01-01

A transient model of a hybrid motor was formulated to study the cause and elimination of non-acoustic combustion instability. The transient model was used to simulate four key tests out of a series of seventeen hybrid motor tests conducted by Thiokol, Rocketdyne and Martin Marietta at NASA/Marshall Space Flight Center (NASA/MSFC). These tests were performed under the Hybrid Propulsion Technology for Launch Vehicle Boosters (HPTLVB) program. The first test resulted in stable combustion. The second test resulted in large-amplitude, 6.5 Hz chamber pressure oscillations that gradually damped away by the end of the test. The third test resulted in large-amplitude, 7.5 Hz chamber pressure oscillations that were sustained throughout the test. The seventh test resulted in the elimination of combustion instability with the installation of an orifice immediately upstream of the injector. The formulation and implementation of the model are the scope of this presentation. The current model is an independent continuation of modeling presented previously by joint Thiokol-Rocketdyne collaborators Boardman, Hawkins, Wassom, and Claflin. The previous model simulated an unstable IR&D hybrid motor test performed by Thiokol. There was very good agreement between the model and the test data. Like the previous model, the current model was developed using Matrix-x simulation software. However, the tests performed at NASA/MSFC under the HPTLVB program were actually simulated. In the current model, the hybrid motor consisting of the liquid oxygen (LOX) injector, the multi-port solid fuel grain and the nozzle was simulated. Also, simulated in the model was the LOX feed system consisting of the tank, venturi, valve and feed lines. All components of the hybrid motor and LOX feed system are treated by a lumped-parameter approach. Agreement between the results of the transient model and the actual test data was very good. This agreement between simulated and actual test data indicated that the combustion instability in the hybrid motor was due to two causes. The first cause was a LOX feed system of insufficient stiffness. The second cause was a LOX injector with an impedance or pressure drop that was too low to provide damping against the feed system oscillations. Also, it was discovered that testing with a new grain of solid fuel sustained the combustion instability. However, testing with a used grain of solid fuel caused the combustion instability to gradually decay.

Study on magnetic force of electromagnetic levitation circular knitting machine

NASA Astrophysics Data System (ADS)

Wu, X. G.; Zhang, C.; Xu, X. S.; Zhang, J. G.; Yan, N.; Zhang, G. Z.

2018-06-01

The structure of the driving coil and the electromagnetic force of the test prototype of electromagnetic-levitation (EL) circular knitting machine are studied. In this paper, the driving coil’s structure and working principle of the EL circular knitting machine are firstly introduced, then the mathematical modelling analysis of the driving electromagnetic force is carried out, and through the Ansoft Maxwell finite element simulation software the coil’s magnetic induction intensity and the needle’s electromagnetic force is simulated, finally an experimental platform is built to measure the coil’s magnetic induction intensity and the needle’s electromagnetic force. The results show that the theoretical analysis, the simulation analysis and the results of the test are very close, which proves the correctness of the proposed model.

Predation scars may influence host susceptibility to pathogens: evaluating the role of corallivores as vectors of coral disease.

PubMed

Nicolet, K J; Chong-Seng, K M; Pratchett, M S; Willis, B L; Hoogenboom, M O

2018-03-27

Infectious diseases not regulated by host density, such as vector-borne diseases, have the potential to drive population declines and extinctions. Here we test the vector potential of the snail Drupella sp. and butterflyfish Chaetodon plebeius for two coral diseases, black band (BBD) and brown band (BrB) disease. Drupella transmitted BrB to healthy corals in 40% of cases immediately following feeding on infected corals, and even in 12% of cases 12 and 24 hours following feeding. However, Drupella was unable to transmit BBD in either transmission treatment. In a field experiment testing the vector potential of naturally-occurring fish assemblages, equivalent numbers of caged and uncaged coral fragments became infected with either BrB, BBD or skeletal eroding band, indicating that corallivorous fish were unlikely to have caused transmission. In aquaria, C. plebeius did not transmit either BBD or BrB, even following extended feeding on both infected and healthy nubbins. A literature review confirmed only four known coral disease vectors, all invertebrates, corroborating our conclusion that polyp-feeding fishes are unlikely to be vectors of coral diseases. This potentially because polyp-feeding fishes produce shallow lesions, not allowing pathogens to invade coral tissues. In contrast, corallivorous invertebrates that create deeper feeding scars increase pathogens transmission.

Optogenetic Activation of a Lateral Hypothalamic-Ventral Tegmental Drive-Reward Pathway.

PubMed

Gigante, Eduardo D; Benaliouad, Faiza; Zamora-Olivencia, Veronica; Wise, Roy A

2016-01-01

Electrical stimulation of the lateral hypothalamus can motivate feeding or can serve as a reward in its own right. It remains unclear whether the same or independent but anatomically overlapping circuitries mediate the two effects. Electrical stimulation findings implicate medial forebrain bundle (MFB) fibers of passage in both effects, and optogenetic studies confirm a contribution from fibers originating in the lateral hypothalamic area and projecting to or through the ventral tegmental area. Here we report that optogenetic activation of ventral tegmental fibers from cells of origin in more anterior or posterior portions of the MFB failed to induce either reward or feeding. The feeding and reward induced by optogenetic activation of fibers from the lateral hypothalamic cells of origin were influenced similarly by variations in stimulation pulse width and pulse frequency, consistent with the hypothesis of a common substrate for the two effects. There were, however, several cases where feeding but not self-stimulation or self-stimulation but not feeding were induced, consistent with the hypothesis that distinct but anatomically overlapping systems mediate the two effects. Thus while optogenetic stimulation provides a more selective tool for characterizing the mechanisms of stimulation-induced feeding and reward, it does not yet resolve the question of common or independent substrates.

Medications and impaired driving.

PubMed

Hetland, Amanda; Carr, David B

2014-04-01

To describe the association of specific medication classes with driving outcomes and provide clinical recommendations. The MEDLINE and EMBASE databases were searched for articles published from January 1973 to June 2013 on classes of medications associated with driving impairment. The search included outcome terms such as automobile driving, motor vehicle crash, driving simulator, and road tests. Only English-language articles that contained findings from observational or interventional designs with ≥ 10 participants were included in this review. Cross-sectional studies, case series, and case reports were excluded. Driving is an important task and activity for the majority of adults. Some commonly prescribed medications have been associated with driving impairment measured by road performance, driving simulation, and/or motor vehicle crashes. This review of 30 studies identified findings with barbiturates, benzodiazepines, hypnotics, antidepressants, opioid and nonsteroidal analgesics, anticonvulsants, antipsychotics, antiparkinsonian agents, skeletal muscle relaxants, antihistamines, anticholinergic medications, and hypoglycemic agents. Additional studies of medication impact on sedation, sleep latency, and psychomotor function, as well as the role of alcohol, are also discussed. Psychotropic agents and those with central nervous system side effects were associated with measures of impaired driving performance. It is difficult to determine if such associations are actually a result of medication use or the medical diagnosis itself. Regardless, clinicians should be aware of the increased risk of impaired driving with specific classes of medications, educate their patients, and/or consider safer alternatives.

Effects of fatigue on driving performance under different roadway geometries: a simulator study.

PubMed

Du, Hongji; Zhao, Xiaohua; Zhang, Xingjian; Zhang, Yunlong; Rong, Jian

2015-01-01

This article examines the effects of fatigue on driving performance under different roadway geometries using a driving simulator. Twenty-four participants each completed a driving scenario twice: while alert and while experiencing fatigue. The driving scenario was composed of straight road segments and curves; there were 6 curves with 3 radius values (i.e., 200, 500, and 800 m) and 2 turning directions (i.e., left and right). Analysis was conducted on driving performance measures such as longitudinal speed, steering wheel movements, and lateral position. RESULTS confirmed that decremental changes in driving performance due to fatigue varied among road conditions. On straight segments, drivers' abilities to steer and maintain lane position were impaired, whereas on curves we found decremental changes in the quality of longitudinal speed as well as steering control and keeping the vehicle in the lane. Moreover, the effects of fatigue on driving performance were relative to the radius and direction of the curve. Fatigue impaired drivers' abilities to control the steering wheel, and the impairment proved more obvious on curves. The degree varied significantly as the curve radius changed. Drivers tended to drive closer to the right side due to fatigue, and the impairment in maintaining lane position became more obvious as the right-turn curve radius decreased. Driver fatigue has detrimental effects on driving performance, and the effects differ under different roadway geometries.

Signalling from the periphery to the brain that regulates energy homeostasis.

PubMed

Kim, Ki-Suk; Seeley, Randy J; Sandoval, Darleen A

2018-04-01

The CNS regulates body weight; however, we still lack a clear understanding of what drives decisions about when, how much and what to eat. A vast array of peripheral signals provides information to the CNS regarding fluctuations in energy status. The CNS then integrates this information to influence acute feeding behaviour and long-term energy homeostasis. Previous paradigms have delegated the control of long-term energy homeostasis to the hypothalamus and short-term changes in feeding behaviour to the hindbrain. However, recent studies have identified target hindbrain neurocircuitry that integrates the orchestration of individual bouts of ingestion with the long-term regulation of energy balance.

LAMMR: A new generation satellite microwave radiometer - Its concepts and capabilities. [Large Antenna Multichannel Microwave Radiometer

NASA Technical Reports Server (NTRS)

Walton, W. T.; Wilheit, T. T.

1981-01-01

Definition studies and baseline design are summarized for the proposed, and now discontinued, LAMMR. The instrument is an offset parabolic reflector with Cassegrain feeds. The three-meter aperture reflector, to be constructed using graphite-epoxy technology, rotates continuously at 0.833 rps. The scan drive subsystem includes momentum compensation for the rotating mass which includes the reflector, the support arm and Cassegrain subreflector, feed horns and radiometer. Two total power radiometers are recommended for each frequency, one each for horizontal and vertical polarizations. The selection plan, definition study specifications, LAMMR performance specifications, and predicted accuracies and resolutions after processing are shown.

Impact of Distracted Driving on Safety and Traffic Flow

PubMed Central

Stavrinos, Despina; Jones, Jennifer L.; Garner, Annie A.; Griffin, Russell; Franklin, Crystal A.; Ball, David; Welburn, Sharon C.; Ball, Karlene K.; Sisiopiku, Virginia P.; Fine, Philip R.

2015-01-01

Studies have documented a link between distracted driving and diminished safety; however, an association between distracted driving and traffic congestion has not been investigated in depth. The present study examined the behavior of teens and young adults operating a driving simulator while engaged in various distractions (i.e., cell phone, texting, and undistracted) and driving conditions (i.e., free flow, stable flow, and oversaturation). Seventy five participants 16 to 25 years of age (split into 2 groups: novice drivers and young adults) drove a STISIM simulator three times, each time with one of three randomly presented distractions. Each drive was designed to represent daytime scenery on a 4 lane divided roadway and included three equal roadway portions representing Levels of Service (LOS) A, C, and E as defined in the 2000 Highway Capacity Manual. Participants also completed questionnaires documenting demographics and driving history. Both safety and traffic flow related driving outcomes were considered. A Repeated Measures Multivariate Analysis of Variance was employed to analyze continuous outcome variables and a Generalized Estimate Equation (GEE) poisson model was used to analyze count variables. Results revealed that, in general more lane deviations and crashes occurred during texting. Distraction (in most cases, text messaging) had a significantly negative impact on traffic flow, such that participants exhibited greater fluctuation in speed, changed lanes significantly fewer times, and took longer to complete the scenario. In turn, more simulated vehicles passed the participant drivers while they were texting or talking on a cell phone than while undistracted. The results indicate that distracted driving, particularly texting, may lead to reduced safety and traffic flow, thus having a negative impact on traffic operations. No significant differences were detected between age groups, suggesting that all drivers, regardless of age, may drive in a manner that impacts safety and traffic flow negatively when distracted. PMID:23465745

Impact of distracted driving on safety and traffic flow.

PubMed

Stavrinos, Despina; Jones, Jennifer L; Garner, Annie A; Griffin, Russell; Franklin, Crystal A; Ball, David; Welburn, Sharon C; Ball, Karlene K; Sisiopiku, Virginia P; Fine, Philip R

2013-12-01

Studies have documented a link between distracted driving and diminished safety; however, an association between distracted driving and traffic congestion has not been investigated in depth. The present study examined the behavior of teens and young adults operating a driving simulator while engaged in various distractions (i.e., cell phone, texting, and undistracted) and driving conditions (i.e., free flow, stable flow, and oversaturation). Seventy five participants 16-25 years of age (split into 2 groups: novice drivers and young adults) drove a STISIM simulator three times, each time with one of three randomly presented distractions. Each drive was designed to represent daytime scenery on a 4 lane divided roadway and included three equal roadway portions representing Levels of Service (LOS) A, C, and E as defined in the 2000 Highway Capacity Manual. Participants also completed questionnaires documenting demographics and driving history. Both safety and traffic flow related driving outcomes were considered. A Repeated Measures Multivariate Analysis of Variance was employed to analyze continuous outcome variables and a Generalized Estimate Equation (GEE) Poisson model was used to analyze count variables. Results revealed that, in general more lane deviations and crashes occurred during texting. Distraction (in most cases, text messaging) had a significantly negative impact on traffic flow, such that participants exhibited greater fluctuation in speed, changed lanes significantly fewer times, and took longer to complete the scenario. In turn, more simulated vehicles passed the participant drivers while they were texting or talking on a cell phone than while undistracted. The results indicate that distracted driving, particularly texting, may lead to reduced safety and traffic flow, thus having a negative impact on traffic operations. No significant differences were detected between age groups, suggesting that all drivers, regardless of age, may drive in a manner that impacts safety and traffic flow negatively when distracted. Copyright © 2013 Elsevier Ltd. All rights reserved.

Estrous Cyclicity in Mice During Simulated Weightlessness

NASA Technical Reports Server (NTRS)

Moyer, E. L.; Talyansky, Y.; Scott, R. T.; Tash, J. S.; Christenson, L. K.; Alwood, J. S.; Ronca, A. E.

2017-01-01

Hindlimb unloading (HU) is a rodent model system used to simulate weightlessness experienced in space. However, some effects of this approach on rodent physiology are under-studied, specifically the effects on ovarian estrogen production which drives the estrous cycle. To resolve this deficiency, we conducted a ground-based validation study using the HU model, while monitoring estrous cycles in 16-weeks-old female C57BL6 mice. Animals were exposed to HU for 12 days following a 3 day HU cage acclimation period, and estrous cycling was analyzed in HU animals (n=22), normally loaded HU Cage Pair-Fed controls (CPF; n=22), and Vivarium controls fed ad libitum (VIV; n=10). Pair feeding was used to control for potential nutritional deficits on ovarian function. Vaginal cells were sampled daily in all mice via saline lavage. Cells were dried and stained with crystal violet, and the smears evaluated using established vaginal cytology techniques by two individuals blinded to the animal treatment group. Estrous cyclicity was disrupted in nearly all HU and CPF mice, while those maintained in VIV had an average normal cycle length of 4.8+/- 0.5 days, with all stages in the cycle visibly observed. CPF and HU animals arrested in the diestrous phase, which precedes the pre-ovulatory estrogen surge. Additionally, infection-like symptoms characterized by vaginal discharge and swelling arose in several HU animals, which we suspect was due to an inability of these mice to properly groom themselves, and/or due to the change in the gravity vector relative to the vaginal opening, which prevented drainage of the lavage solution. Pair-feeding resulted in similar weight gains of HU and CPF (1.5% vs 3.0%, respectively). The current results indicate that pair-feeding controlled weight gain and that the HU cage alone influenced estrous cyclicity. Thus, longer acclimation needs to be tested to determine if and when normal estrous cycling resumes in non-loaded mice in HU cages prior to HU testing. Future studies might also examine whether modifications to the vaginal lavage procedure might prevent the onset of the infection-like symptoms, and allow estrous cyclicity to be measured in this model system. Research supported by NNX15AB48G to JST.

Next-day residual effects of gabapentin, diphenhydramine, and triazolam on simulated driving performance in healthy volunteers: a phase 3, randomized, double-blind, placebo-controlled, crossover trial.

PubMed

Kay, Gary G; Schwartz, Howard I; Wingertzahn, Mark A; Jayawardena, Shyamalie; Rosenberg, Russell P

2016-05-01

Next-day residual effects of a nighttime dose of gabapentin 250 mg were evaluated on simulated driving performance in healthy participants in a randomized, placebo-controlled, double-blind, multicenter, four-period crossover study that included diphenhydramine citrate 76 mg and triazolam 0.5 mg. At treatment visits, participants (n = 59) were dosed at ~23:30, went to bed immediately, and awakened 6.5 h postdose for evaluation. The primary endpoint was the standard deviation of lateral position for the 100-km driving scenario. Additional measures of driving, sleepiness, and cognition were included. Study sensitivity was established with triazolam, which demonstrated significant next-day impairment on all driving endpoints, relative to placebo (p < 0.001). Gabapentin demonstrated noninferiority to placebo on standard deviation of lateral position and speed deviation but not for lane excursions. Diphenhydramine citrate demonstrated significant impairment relative to gabapentin and placebo on speed deviation (p < 0.05). Other comparisons were either nonsignificant or statistically ineligible per planned, sequential comparisons. Secondary endpoints for sleepiness and cognitive performance were supportive of these conclusions. Together, these data suggest that low-dose gabapentin had no appreciable next-day effects on simulated driving performance or cognitive functioning. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Fuel magnetization without external field coils (AutoMag)

NASA Astrophysics Data System (ADS)

Slutz, Stephen; Jennings, Christopher; Awe, Thomas; Shipley, Gabe; Lamppa, Derek; McBride, Ryan

2016-10-01

Magnetized Liner Inertial Fusion (MagLIF) has produced fusion-relevant plasma conditions on the Z accelerator where the fuel was magnetized using external field coils. We present a novel concept that does not need external field coils. This concept (AutoMag) magnetizes the fuel during the early part of the drive current by using a composite liner with helical conduction paths separated by insulating material. The drive is designed so the current rises slowly enough to avoid electrical breakdown of the insulators until a sufficiently strong magnetic field is established. Then the current rises more quickly, which causes the insulators to break down allowing the drive current to follow an axial path and implode the liner. Low inductance magnetically insulated power feeds can be used with AutoMag to increase the drive current without interfering with diagnostic access. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

LOW ACTIVITY WASTE FEED SOLIDS CARACTERIZATION AND FILTERABILITY TESTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCabe, D.; Crawford, C.; Duignan, M.

The primary treatment of the tank waste at the DOE Hanford site will be done in the Waste Treatment and Immobilization Plant (WTP) that is currently under construction. The baseline plan for the WTP Pretreatment facility is to treat the waste, splitting it into High Level Waste (HLW) feed and Low Activity Waste (LAW) feed. Both waste streams are then separately vitrified as glass and sealed in canisters. The LAW glass will be disposed onsite in the Integrated Disposal Facility (IDF). There are currently no plans to treat the waste to remove technetium in the WTP Pretreatment facility, so itsmore » disposition path is the LAW glass. Options are being explored to immobilize the LAW portion of the tank waste, i.e., the LAW feed from the WTP Pretreatment facility. Removal of {sup 99}Tc from the LAW Feed, followed by off-site disposal of the {sup 99}Tc, would eliminate a key risk contributor for the IDF Performance Assessment (PA) for supplemental waste forms, and has potential to reduce treatment and disposal costs. Washington River Protection Solutions (WRPS) is developing some conceptual flow sheets for LAW treatment and disposal that could benefit from technetium removal. One of these flowsheets will specifically examine removing {sup 99}Tc from the LAW feed stream to supplemental immobilization. The conceptual flow sheet of the {sup 99}Tc removal process includes a filter to remove insoluble solids prior to processing the stream in an ion exchange column, but the characteristics and behavior of the liquid and solid phases has not previously been investigated. This report contains results of testing of a simulant that represents the projected composition of the feed to the Supplemental LAW process. This feed composition is not identical to the aqueous tank waste fed to the Waste Treatment Plant because it has been processed through WTP Pretreatment facility and therefore contains internal changes and recycle streams that will be generated within the WTP process. Although a Supplemental LAW feed simulant has previously been prepared, this feed composition differs from that simulant because those tests examined only the fully soluble aqueous solution at room temperature, not the composition formed after evaporation, including the insoluble solids that precipitate after it cools. The conceptual flow sheet for Supplemental LAW immobilization has an option for removal of {sup 99}Tc from the feed stream, if needed. Elutable ion exchange has been selected for that process. If implemented, the stream would need filtration to remove the insoluble solids prior to processing in an ion exchange column. The characteristics, chemical speciation, physical properties, and filterability of the solids are important to judge the feasibility of the concept, and to estimate the size and cost of a facility. The insoluble solids formed during these tests were primarily natrophosphate, natroxalate, and a sodium aluminosilicate compound. At the elevated temperature and 8 M [Na+], appreciable insoluble solids (1.39 wt%) were present. Cooling to room temperature and dilution of the slurry from 8 M to 5 M [Na+] resulted in a slurry containing 0.8 wt% insoluble solids. The solids (natrophosphate, natroxalate, sodium aluminum silicate, and a hydrated sodium phosphate) were relatively stable and settled quickly. Filtration rates were in the range of those observed with iron-based simulated Hanford tank sludge simulants, e.g., 6 M [Na+] Hanford tank 241-AN-102, even though their chemical speciation is considerably different. Chemical cleaning of the crossflow filter was readily accomplished with acid. As this simulant formulation was based on an average composition of a wide range of feeds using an integrated computer model, this exact composition may never be observed. But the test conditions were selected to enable comparison to the model to enable improving its chemical prediction capability.« less

Network Flow Simulation of Fluid Transients in Rocket Propulsion Systems

NASA Technical Reports Server (NTRS)

Bandyopadhyay, Alak; Hamill, Brian; Ramachandran, Narayanan; Majumdar, Alok

2011-01-01

Fluid transients, also known as water hammer, can have a significant impact on the design and operation of both spacecraft and launch vehicle propulsion systems. These transients often occur at system activation and shutdown. The pressure rise due to sudden opening and closing of valves of propulsion feed lines can cause serious damage during activation and shutdown of propulsion systems. During activation (valve opening) and shutdown (valve closing), pressure surges must be predicted accurately to ensure structural integrity of the propulsion system fluid network. In the current work, a network flow simulation software (Generalized Fluid System Simulation Program) based on Finite Volume Method has been used to predict the pressure surges in the feed line due to both valve closing and valve opening using two separate geometrical configurations. The valve opening pressure surge results are compared with experimental data available in the literature and the numerical results compared very well within reasonable accuracy (< 5%) for a wide range of inlet-to-initial pressure ratios. A Fast Fourier Transform is preformed on the pressure oscillations to predict the various modal frequencies of the pressure wave. The shutdown problem, i.e. valve closing problem, the simulation results are compared with the results of Method of Characteristics. Most rocket engines experience a longitudinal acceleration, known as "pogo" during the later stage of engine burn. In the shutdown example problem, an accumulator has been used in the feed system to demonstrate the "pogo" mitigation effects in the feed system of propellant. The simulation results using GFSSP compared very well with the results of Method of Characteristics.

The application of integral performance criteria to the analysis of discrete maneuvers in a driving simulator

NASA Technical Reports Server (NTRS)

Repa, B. S.; Zucker, R. S.; Wierwille, W. W.

1977-01-01

The influence of vehicle transient response characteristics on driver-vehicle performance in discrete maneuvers as measured by integral performance criteria was investigated. A group of eight ordinary drivers was presented with a series of eight vehicle transfer function configurations in a driving simulator. Performance in two discrete maneuvers was analyzed by means of integral performance criteria. Results are presented.

LMSS drive simulator for multipath propagation

NASA Technical Reports Server (NTRS)

Vishakantaiah, Praveen; Vogel, Wolfhard J.

1989-01-01

A three-dimensional drive simulator for the prediction of Land Mobile Satellite Service (LMSS) multipath propagation was developed. It is based on simple physical and geometrical rules and can be used to evaluate effects of scatterer numbers and positions, receiving antenna pattern, and satellite frequency and position. It is shown that scatterers close to the receiver have the most effect and that directive antennas suppress multipath interference.

Environmentally sustainable production of food, feed and fuel from natural resources in the tropics.

PubMed

Preston, T Reg

2009-08-01

Responding to the challenges posed by global warming, peak oil and biofuels will require a paradigm shift in the practice of agriculture and in the role of live stock within the farming system. Farming systems should aim at maximizing plant biomass production from locally available diversified resources, processing of the biomass on farm to provide food, feed and energy and recycling of all waste materials. The approach that is the subject of this paper is that the generation of electricity can be a by-product of food/feed production. The concept is the fractionation of biomass into inedible cell wall material that can be converted to an inflammable gas by gasification, the gas in turn being the source of fuel for internal combustion engines driving electrical generators. The cell contents and related structures such as tree leaves are used as human food or animal feed. As well as providing food and feed the model is highly appropriate for decentralized small scale production of electricity in rural areas. It also offers opportunities for sequestration of carbon in the form of biochar the solid residue remaining after gasification of the biomass.

Establishment of an Artificial Tick Feeding System to Study Theileria lestoquardi Infection

PubMed Central

Tajeri, Shahin; Razmi, Gholamreza; Haghparast, Alireza

2016-01-01

The establishment of good experimental models for Theileria sp. infection is important for theileriosis research. Routinely, infection of ticks is accomplished by feeding on parasite-infected animals (sheep, cows and horses), which raises practical and ethical problems, driving the search for alternative methods of tick infection. Artificial tick feeding systems are based mainly on rearing ticks on host-derived or hand-made artificial membranes. We developed a modified feeding assay for infecting nymphal stages of Hyalomma anatolicum ticks with Theileria lestoquardi, a highly pathogenic parasite of sheep. We compared two different membranes: an artificial silicone membrane and a natural alternative using mouse skin. We observed high attachment rates with mouse skin, whereas in vitro feeding of H. anatolicum nymphs on silicone membranes was unsuccessful. We could infect H. anatolicum nymphs with T. lestoquardi and the emerging adult ticks transmitted infective parasites to sheep. In contrast, similar infections with Rhipicephalus bursa, a representative tick with short mouth-parts that was proposed as a vector for T. lestoquardi, appeared not to be a competent vector tick species. This is the first report of an experimentally controlled infection of H. anatolicum with T. lestoquardi and opens avenues to explore tick-parasite dynamics in detail. PMID:28036364

Effect of influx on the free surface transport within a hollow ampule

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, S.C.; Vafai, K.

1994-07-01

A numerical investigation of free surface transport within a hollow glass ampule with feed-in boundary conditions is presented. The glass ampule is treated as a vertical film with a finite pressure difference across the film, with applied influx on the upper boundary, and with applied heat flux at the outer free surface. Two different sizes of glass ampules, along with different influx values are investigated. A finite element method with full consideration of surface tension and viscosity effects is used to solve the transient Navier-Stokes equations in cylindrical coordinates. Radiative and convective boundary conditions are incorporated when solving the energymore » equation. The movement of the inner and outer free surfaces with the specified feed-in velocity for different dimensions and temporal temperature distribution are analyzed. It is found that the feed-in mechanism rather than the pressure difference provides the more dominant driving forces. Also studied is the effect of using different feed-in velocities on the flow and temperature fields. The results presented in this work illustrate the basic effects of the feed-in mechanism of the free surface transport phenomenon.« less

Cellular automata simulation of topological effects on the dynamics of feed-forward motifs

PubMed Central

Apte, Advait A; Cain, John W; Bonchev, Danail G; Fong, Stephen S

2008-01-01

Background Feed-forward motifs are important functional modules in biological and other complex networks. The functionality of feed-forward motifs and other network motifs is largely dictated by the connectivity of the individual network components. While studies on the dynamics of motifs and networks are usually devoted to the temporal or spatial description of processes, this study focuses on the relationship between the specific architecture and the overall rate of the processes of the feed-forward family of motifs, including double and triple feed-forward loops. The search for the most efficient network architecture could be of particular interest for regulatory or signaling pathways in biology, as well as in computational and communication systems. Results Feed-forward motif dynamics were studied using cellular automata and compared with differential equation modeling. The number of cellular automata iterations needed for a 100% conversion of a substrate into a target product was used as an inverse measure of the transformation rate. Several basic topological patterns were identified that order the specific feed-forward constructions according to the rate of dynamics they enable. At the same number of network nodes and constant other parameters, the bi-parallel and tri-parallel motifs provide higher network efficacy than single feed-forward motifs. Additionally, a topological property of isodynamicity was identified for feed-forward motifs where different network architectures resulted in the same overall rate of the target production. Conclusion It was shown for classes of structural motifs with feed-forward architecture that network topology affects the overall rate of a process in a quantitatively predictable manner. These fundamental results can be used as a basis for simulating larger networks as combinations of smaller network modules with implications on studying synthetic gene circuits, small regulatory systems, and eventually dynamic whole-cell models. PMID:18304325

A NEW TECHNIQUE FOR THE PHOTOSPHERIC DRIVING OF NON-POTENTIAL SOLAR CORONAL MAGNETIC FIELD SIMULATIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weinzierl, Marion; Yeates, Anthony R.; Mackay, Duncan H.

2016-05-20

In this paper, we develop a new technique for driving global non-potential simulations of the Sun’s coronal magnetic field solely from sequences of radial magnetic maps of the solar photosphere. A primary challenge to driving such global simulations is that the required horizontal electric field cannot be uniquely determined from such maps. We show that an “inductive” electric field solution similar to that used by previous authors successfully reproduces specific features of the coronal field evolution in both single and multiple bipole simulations. For these cases, the true solution is known because the electric field was generated from a surfacemore » flux-transport model. The match for these cases is further improved by including the non-inductive electric field contribution from surface differential rotation. Then, using this reconstruction method for the electric field, we show that a coronal non-potential simulation can be successfully driven from a sequence of ADAPT maps of the photospheric radial field, without including additional physical observations which are not routinely available.« less

ALCOHOL AND DISTRACTION INTERACT TO IMPAIR DRIVING PERFORMANCE

PubMed Central

Harrison, Emily L. R.; Fillmore, Mark T.

2011-01-01

Background Recognition of the risks associated with alcohol intoxication and driver distraction has led to a wealth of simulated driving research aimed at studying the adverse effects of each of these factors. Research on driving has moved beyond the individual, separate examination of these factors to the examination of potential interactions between alcohol intoxication and driver distraction. In many driving situations, distractions are commonplace and might have little or no disruptive influence on primary driving functions. Yet, such distractions might become disruptive to a driver who is intoxicated. Methods The present study examined the interactive impairing effects of alcohol intoxication and driver distraction on simulated driving performance in 40 young adult drivers using a divided attention task as a distracter activity. The interactive influence of alcohol and distraction was tested by having drivers perform the driving task under four different conditions: 0.65 g/kg alcohol; 0.65 g/kg alcohol + divided attention; placebo; and placebo + divided attention. Results As hypothesized, divided attention had no impairing effect on driving performance in sober drivers. However, under alcohol, divided attention exacerbated the impairing effects of alcohol on driving precision. Conclusions Alcohol and distraction continue to be appropriate targets for research into ways to reduce the rates of driving-related fatalities and injuries. Greater consideration of how alcohol and distraction interact to impair aspects of driving performance can further efforts to create prevention and intervention measures to protect drivers, particularly young adults. PMID:21277119

Alcohol and distraction interact to impair driving performance.

PubMed

Harrison, Emily L R; Fillmore, Mark T

2011-08-01

Recognition of the risks associated with alcohol intoxication and driver distraction has led to a wealth of simulated driving research aimed at studying the adverse effects of each of these factors. Research on driving has moved beyond the individual, separate examination of these factors to the examination of potential interactions between alcohol intoxication and driver distraction. In many driving situations, distractions are commonplace and might have little or no disruptive influence on primary driving functions. Yet, such distractions might become disruptive to a driver who is intoxicated. The present study examined the interactive impairing effects of alcohol intoxication and driver distraction on simulated driving performance in 40 young adult drivers using a divided attention task as a distracter activity. The interactive influence of alcohol and distraction was tested by having drivers perform the driving task under four different conditions: 0.65 g/kg alcohol; 0.65 g/kg alcohol+divided attention; placebo; and placebo+divided attention. As hypothesized, divided attention had no impairing effect on driving performance in sober drivers. However, under alcohol, divided attention exacerbated the impairing effects of alcohol on driving precision. Alcohol and distraction continue to be appropriate targets for research into ways to reduce the rates of driving-related fatalities and injuries. Greater consideration of how alcohol and distraction interact to impair aspects of driving performance can further efforts to create prevention and intervention measures to protect drivers, particularly young adults. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Conceptual design study of a visual system for a rotorcraft simulator and some advances in platform motion utilization

NASA Technical Reports Server (NTRS)

Sinacori, J. B.

1980-01-01

A conceptual design of a visual system for a rotorcraft flight simulator is presented. Also, drive logic elements for a coupled motion base for such a simulator are given. The design is the result of an assessment of many potential arrangements of electro-optical elements and is a concept considered feasible for the application. The motion drive elements represent an example logic for a coupled motion base and is essentially an appeal to the designers of such logic to combine their washout and braking functions.

Loss of feed flow, steam generator tube rupture and steam line break thermohydraulic experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mendler, O J; Takeuchi, K; Young, M Y

1986-10-01

The Westinghouse Model Boiler No. 2 (MB-2) steam generator test model at the Engineering Test Facility in Tampa, Florida, was reinstrumented and modified for performing a series of tests simulating steam generator accident transients. The transients simulated were: loss of feed flow, steam generator tube rupture, and steam line break events. This document presents a description of (1) the model boiler and the associated test facility, (2) the tests performed, and (3) the analyses of the test results.

Polar-Drive--Implosion Physics on OMEGA and the NIF

NASA Astrophysics Data System (ADS)

Radha, P. B.

2012-10-01

Polar drive (PD) permits the execution of direct-drive--ignition experiments on facilities that are configured for x-ray drive such as the National Ignition Facility (NIF) and Laser M'egajoule. Experiments on the OMEGA laser are used to develop and validate models of PD implosions. Results from OMEGA PD shock-timing and warm implosions are presented. Experiments are simulated with the 2-D hydrodynamic code DRACO including full 3-D ray trace to model oblique beams. Excellent agreement is obtained in shock velocity and catch-up in PD geometry in warm, plastic shells. Predicted areal densities are measured in PD implosion experiments. Good agreement between simulation and experiments is obtained in the overall shape of the compressing shell when observed through x-ray backlighting. Simulated images of the hot core, including the effect of magnetic fields, are compared with experiments. Comparisons of simulated and observed scattered light and bang time in PD geometry are presented. Several techniques to increase implosion velocity are presented including beam profile variations and different ablator materials. Results from shimmed-target PD experiments will also be presented. Designs for future PD OMEGA experiments at ignition-relevant intensities will be presented. The implication of these results for NIF-scale plasmas is discussed. Experiments for the NIF in its current configuration, with indirect-drive phase plates, are proposed to study implosion energetics and shell asymmetries. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC52-08NA28302.

Metabolic Demand of Driving Among Adults with Type 1 Diabetes Mellitus (T1DM)

PubMed Central

Cox, Daniel J.; Singh, Harsimran; Clarke, William L.; Anderson, Stacey M.; Kovatchev, Boris P.; Gonder-Frederick, Linda A.

2010-01-01

Recent research suggests that the frequency of driving mishaps is increased in people with Type 1 diabetes (T1DM) as compared to those with Type 2 diabetes or their non-diabetic spouses. This study involved a sample of T1DM drivers and was designed to investigate the metabolic and physiologic demands of driving compared to sitting passively. Participants (N=38) were divided into two groups: the -History group included those reporting no driving mishaps in the past two years, and the +History group included participants reporting at least two such mishaps in the past two years. Glucose utilization rates were determined in participants while: (a) they were driving a virtual reality driving simulator for 30 minutes, and (b) watching a 30-minute video. Blood glucose (BG) levels were maintained at similar levels during both procedures. Other biological variables including heart rate (HR) were monitored. Participants rated their hypoglycemia (low BG) symptoms before and after each of the two procedures. . Participants could self-treat if they perceived they were experiencing hypoglycemia. There were no differences between the two groups. However, glucose utilization rates were significantly higher during the driving scenario (3.83mg/kg/min + 1.7 vs. 3.37 mg/kg/min + 1.6, p=0.047). HR was significantly higher during the driving scenario. Drivers reported more autonomic symptoms during driving and 32% treated perceived hypoglycemia during driving. Driving a virtual reality simulator is associated with increased glucose utilization rates suggesting that driving per se has a metabolic cost and that BG should be measured prior to driving and periodically during long drives. PMID:21050619

It's not just what you eat but when: The impact of eating a meal during simulated shift work on driving performance.

PubMed

Gupta, Charlotte C; Dorrian, Jill; Grant, Crystal L; Pajcin, Maja; Coates, Alison M; Kennaway, David J; Wittert, Gary A; Heilbronn, Leonie K; Della Vedova, Chris B; Banks, Siobhan

2017-01-01

Shiftworkers have impaired performance when driving at night and they also alter their eating patterns during nightshifts. However, it is unknown whether driving at night is influenced by the timing of eating. This study aims to explore the effects of timing of eating on simulated driving performance across four simulated nightshifts. Healthy, non-shiftworking males aged 18-35 years (n = 10) were allocated to either an eating at night (n = 5) or no eating at night (n = 5) condition. During the simulated nightshifts at 1730, 2030 and 0300 h, participants performed a 40-min driving simulation, 3-min Psychomotor Vigilance Task (PVT-B), and recorded their ratings of sleepiness on a subjective scale. Participants had a 6-h sleep opportunity during the day (1000-1600 h). Total 24-h food intake was consistent across groups; however, those in the eating at night condition ate a large meal (30% of 24-h intake) during the nightshift at 0130 h. It was found that participants in both conditions experienced increased sleepiness and PVT-B impairments at 0300 h compared to 1730 and 2030 h (p < 0.001). Further, at 0300 h, those in the eating condition displayed a significant decrease in time spent in the safe zone (p < 0.05; percentage of time within 10 km/h of the speed limit and 0.8 m of the centre of the lane) and significant increases in speed variability (p < 0.001), subjective sleepiness (p < 0.01) and number of crashes (p < 0.01) compared to those in the no eating condition. Results suggest that, for optimal performance, shiftworkers should consider restricting food intake during the night.

A parametric duration model of the reaction times of drivers distracted by mobile phone conversations.

PubMed

Haque, Md Mazharul; Washington, Simon

2014-01-01

The use of mobile phones while driving is more prevalent among young drivers-a less experienced cohort with elevated crash risk. The objective of this study was to examine and better understand the reaction times of young drivers to a traffic event originating in their peripheral vision whilst engaged in a mobile phone conversation. The CARRS-Q advanced driving simulator was used to test a sample of young drivers on various simulated driving tasks, including an event that originated within the driver's peripheral vision, whereby a pedestrian enters a zebra crossing from a sidewalk. Thirty-two licensed drivers drove the simulator in three phone conditions: baseline (no phone conversation), hands-free and handheld. In addition to driving the simulator each participant completed questionnaires related to driver demographics, driving history, usage of mobile phones while driving, and general mobile phone usage history. The participants were 21-26 years old and split evenly by gender. Drivers' reaction times to a pedestrian in the zebra crossing were modelled using a parametric accelerated failure time (AFT) duration model with a Weibull distribution. Also tested where two different model specifications to account for the structured heterogeneity arising from the repeated measures experimental design. The Weibull AFT model with gamma heterogeneity was found to be the best fitting model and identified four significant variables influencing the reaction times, including phone condition, driver's age, license type (provisional license holder or not), and self-reported frequency of usage of handheld phones while driving. The reaction times of drivers were more than 40% longer in the distracted condition compared to baseline (not distracted). Moreover, the impairment of reaction times due to mobile phone conversations was almost double for provisional compared to open license holders. A reduction in the ability to detect traffic events in the periphery whilst distracted presents a significant and measurable safety concern that will undoubtedly persist unless mitigated. Copyright © 2013 Elsevier Ltd. All rights reserved.

Modeling of Passive Forces of Machine Tool Covers

NASA Astrophysics Data System (ADS)

Kolar, Petr; Hudec, Jan; Sulitka, Matej

The passive forces acting against the drive force are phenomena that influence dynamical properties and precision of linear axes equipped with feed drives. Covers are one of important sources of passive forces in machine tools. The paper describes virtual evaluation of cover passive forces using the cover complex model. The model is able to compute interaction between flexible cover segments and sealing wiper. The result is deformation of cover segments and wipers which is used together with measured friction coefficient for computation of cover total passive force. This resulting passive force is dependent on cover position. Comparison of computational results and measurement on the real cover is presented in the paper.

Evaluating wildlife-cattle contact rates to improve the understanding of dynamics of bovine tuberculosis transmission in Michigan, USA.

PubMed

Lavelle, Michael J; Kay, Shannon L; Pepin, Kim M; Grear, Daniel A; Campa, Henry; VerCauteren, Kurt C

2016-12-01

Direct and indirect contacts among individuals drive transmission of infectious disease. When multiple interacting species are susceptible to the same pathogen, risk assessment must include all potential host species. Bovine tuberculosis (bTB) is an example of a disease that can be transmitted among several wildlife species and to cattle, although the potential role of several wildlife species in spillback to cattle remains unclear. To better understand the complex network of contacts and factors driving disease transmission, we fitted proximity logger collars to beef and dairy cattle (n=37), white-tailed deer (Odocoileus virginianus; n=29), raccoon (Procyon lotor; n=53), and Virginia opossum (Didelphis virginiana; n=79) for 16 months in Michigan's Lower Peninsula, USA. We determined inter- and intra-species direct and indirect contact rates. Data on indirect contact was calculated when collared animals visited stationary proximity loggers placed at cattle feed and water resources. Most contact between wildlife species and cattle was indirect, with the highest contact rates occurring between raccoons and cattle during summer and fall. Nearly all visits (>99%) to cattle feed and water sources were by cattle, whereas visitation to stored cattle feed was dominated by deer and raccoon (46% and 38%, respectively). Our results suggest that indirect contact resulting from wildlife species visiting cattle-related resources could pose a risk of disease transmission to cattle and deserves continued attention with active mitigation. Published by Elsevier B.V.

Simulation of three-phase induction motor drives using indirect field oriented control in PSIM environment

NASA Astrophysics Data System (ADS)

Aziri, Hasif; Patakor, Fizatul Aini; Sulaiman, Marizan; Salleh, Zulhisyam

2017-09-01

This paper presents the simulation of three-phase induction motor drives using Indirect Field Oriented Control (IFOC) in PSIM environment. The asynchronous machine is well known about natural limitations fact of highly nonlinearity and complexity of motor model. In order to resolve these problems, the IFOC is applied to control the instantaneous electrical quantities such as torque and flux component. As FOC is controlling the stator current that represented by a vector, the torque component is aligned with d coordinate while the flux component is aligned with q coordinate. There are five levels of the incremental system are gradually built up to verify and testing the software module in the system. Indeed, all of system build levels are verified and successfully tested in PSIM environment. Moreover, the corresponding system of five build levels are simulated in PSIM environment which is user-friendly for simulation studies in order to explore the performance of speed responses based on IFOC algorithm for three-phase induction motor drives.

The effects of texting on driving performance in a driving simulator: the influence of driver age.

PubMed

Rumschlag, Gordon; Palumbo, Theresa; Martin, Amber; Head, Doreen; George, Rajiv; Commissaris, Randall L

2015-01-01

Distracted driving is a significant contributor to motor vehicle accidents and fatalities, and texting is a particularly significant form of driver distraction that continues to be on the rise. The present study examined the influence of driver age (18-59 years old) and other factors on the disruptive effects of texting on simulated driving behavior. While 'driving' the simulator, subjects were engaged in a series of brief text conversations with a member of the research team. The primary dependent variable was the occurrence of Lane Excursions (defined as any time the center of the vehicle moved outside the directed driving lane, e.g., into the lane for oncoming traffic or onto the shoulder of the road), measured as (1) the percent of subjects that exhibited Lane Excursions, (2) the number of Lane Excursions occurring and (3) the percent of the texting time in Lane Excursions. Multiple Regression analyses were used to assess the influence of several factors on driving performance while texting, including text task duration, texting skill level (subject-reported), texting history (#texts/week), driver gender and driver age. Lane Excursions were not observed in the absence of texting, but 66% of subjects overall exhibited Lane Excursions while texting. Multiple Regression analysis for all subjects (N=50) revealed that text task duration was significantly correlated with the number of Lane Excursions, and texting skill level and driver age were significantly correlated with the percent of subjects exhibiting Lane Excursions. Driver gender was not significantly correlated with Lane Excursions during texting. Multiple Regression analysis of only highly skilled texters (N=27) revealed that driver age was significantly correlated with the number of Lane Excursions, the percent of subjects exhibiting Lane Excursions and the percent of texting time in Lane Excursions. In contrast, Multiple Regression analysis of those drivers who self-identified as not highly skilled texters (N=23) revealed that text task duration was significantly correlated with the number of Lane Excursions. The present studies confirm past reports that texting impairs driving simulator performance. Moreover, the present study demonstrates that for highly skilled texters, the effects of texting on driving are actually worse for older drivers. Given the increasing frequency of texting while driving within virtually all age groups, these data suggest that 'no texting while driving' education and public service messages need to be continued, and they should be expanded to target older drivers as well. Copyright © 2014 Elsevier Ltd. All rights reserved.

Assessment of duration of the drive operation in the mode of kinetic energy recovery under power supply voltage sags in electrical grids of mechanical engineering enterprises

NASA Astrophysics Data System (ADS)

Shonin, O. B.; Novozhilov, N. G.

2017-02-01

Voltage sags in electric grids of mechanical engineering enterprises may lead to disconnection of important power consumers with variable frequency drives from the power grid and further interruption of the production process. The paper considers a sensorless V/f control system of еру induction motor drive under normal conditions and under voltage sags on the basis of a computer model of the drive and derivation of a formula for assessment of possible duration of the drive operation in the mode of controlled recovery of kinetic energy accumulated in rotating mass of the drive. Results of simulations have been used to validate results of calculations of the rotor velocity deceleration made in a closed form obtained from the equation reflecting the balance of torques. It is shown that results of calculations practically coincide with results of simulations in the range up to 5% of the velocity initial value. The proposed formula may be useful for estimation of the duration of the drive operation in the mode of recovery of kinetic energy depending on parameters of the motor and driven mechanisms.

The sensitivity of laboratory tests assessing driving related skills to dose-related impairment of alcohol: A literature review.

PubMed

Jongen, S; Vuurman, E F P M; Ramaekers, J G; Vermeeren, A

2016-04-01

Laboratory tests assessing driving related skills can be useful as initial screening tools to assess potential drug induced impairment as part of a standardized behavioural assessment. Unfortunately, consensus about which laboratory tests should be included to reliably assess drug induced impairment has not yet been reached. The aim of the present review was to evaluate the sensitivity of laboratory tests to the dose dependent effects of alcohol, as a benchmark, on performance parameters. In total, 179 experimental studies were included. Results show that a cued go/no-go task and a divided attention test with primary tracking and secondary visual search were consistently sensitive to the impairing effects at medium and high blood alcohol concentrations. Driving performance assessed in a simulator was less sensitive to the effects of alcohol as compared to naturalistic, on-the-road driving. In conclusion, replicating results of several potentially useful tests and their predictive validity of actual driving impairment should deserve further research. In addition, driving simulators should be validated and compared head to head to naturalistic driving in order to increase construct validity. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Blue-Enriched White Light Enhances Physiological Arousal But Not Behavioral Performance during Simulated Driving at Early Night

PubMed Central

Rodríguez-Morilla, Beatriz; Madrid, Juan A.; Molina, Enrique; Correa, Angel

2017-01-01

Vigilance usually deteriorates over prolonged driving at non-optimal times of day. Exposure to blue-enriched light has shown to enhance arousal, leading to behavioral benefits in some cognitive tasks. However, the cognitive effects of long-wavelength light have been less studied and its effects on driving performance remained to be addressed. We tested the effects of a blue-enriched white light (BWL) and a long-wavelength orange light (OL) vs. a control condition of dim light on subjective, physiological and behavioral measures at 21:45 h. Neurobehavioral tests included the Karolinska Sleepiness Scale and subjective mood scale, recording of distal-proximal temperature gradient (DPG, as index of physiological arousal), accuracy in simulated driving and reaction time in the auditory psychomotor vigilance task. The results showed that BWL decreased the DPG (reflecting enhanced arousal), while it did not improve reaction time or driving performance. Instead, blue light produced larger driving errors than OL, while performance in OL was stable along time on task. These data suggest that physiological arousal induced by light does not necessarily imply cognitive improvement. Indeed, excessive arousal might deteriorate accuracy in complex tasks requiring precision, such as driving. PMID:28690558

A Study of a Handrim-Activated Power-Assist Wheelchair Based on a Non-Contact Torque Sensor

PubMed Central

Nam, Ki-Tae; Jang, Dae-Jin; Kim, Yong Chol; Heo, Yoon; Hong, Eung-Pyo

2016-01-01

Demand for wheelchairs is increasing with growing numbers of aged and disabled persons. Manual wheelchairs are the most commonly used assistive device for mobility because they are convenient to transport. Manual wheelchairs have several advantages but are not easy to use for the elderly or those who lack muscular strength. Therefore, handrim-activated power-assist wheelchairs (HAPAW) that can aid driving power with a motor by detecting user driving intentions through the handrim are being researched. This research will be on HAPAW that judge user driving intentions by using non-contact torque sensors. To deliver the desired motion, which is sensed from handrim rotation relative to a fixed controller, a new driving wheel mechanism is designed by applying a non-contact torque sensor, and corresponding torques are simulated. Torques are measured by a driving wheel prototype and compared with simulation results. The HAPAW prototype was developed using the wheels and a driving control algorithm that uses left and right input torques and time differences are used to check if the non-contact torque sensor can distinguish users’ driving intentions. Through this procedure, it was confirmed that the proposed sensor can be used effectively in HAPAW. PMID:27509508

Large Survey of Neutron Spectrum Moments Due to ICF Drive Asymmetry

NASA Astrophysics Data System (ADS)

Field, J. E.; Munro, D.; Spears, B.; Peterson, J. L.; Brandon, S.; Gaffney, J. A.; Hammer, J.; Langer, S.; Nora, R. C.; Springer, P.; ICF Workflow Collaboration Collaboration

2016-10-01

We have recently completed the largest HYDRA simulation survey to date ( 60 , 000 runs) of drive asymmetry on the new Trinity computer at LANL. The 2D simulations covered a large space of credible perturbations to the drive of ICF implosions on the NIF. Cumulants of the produced birth energy spectrum for DD and DT reaction neutrons were tallied using new methods. Comparison of the experimental spectra with our map of predicted spectra from simulation should provide a wealth of information about the burning plasma region. We report on our results, highlighting areas of agreement (and disagreement) with experimental spectra. We also identify features in the predicted spectra that might be amenable to measurement with improved diagnostics. Prepared by LLNL under Contract DE-AC52-07NA27344. IM release #: LLNL-PROC-697321.

Distractions N' Driving: video game simulation educates young drivers on the dangers of texting while driving.

PubMed

Saqer, Haneen; de Visser, Ewart; Strohl, Jonathan; Parasuraman, Raja

2012-01-01

The proliferation of portable communication and entertainment devices has introduced new dangers to the driving environment, particularly for young and inexperienced drivers. Graduate students from George Mason University illustrate a powerful, practical, and cost-effective program that has been successful in educating these drivers on the dangers of texting while driving, which can easily be adapted and implemented in other communities.

From Geochemistry to Biochemistry: Simulating Prebiotic Chemistry Driven by Geochemical Gradients in Alkaline Hydrothermal Vents

NASA Astrophysics Data System (ADS)

Barge, Laurie

2016-07-01

Planetary water-rock interfaces generate energy in the form of redox, pH, and thermal gradients, and these disequilibria are particularly focused in hydrothermal vent systems where the reducing, heated hydrothermal fluid feeds back into the more oxidizing ocean. Alkaline hydrothermal vents have been proposed as a likely location for the origin of life on the early Earth due to various factors: including the hydrothermal pH / Eh gradients that resemble the ubiquitous electrical / proton gradients in biology, the catalytic hydrothermal precipitates that resemble inorganic catalysts in enzymes, and the presence of electron donors and acceptors in hydrothermal systems (e.g. H2 + CH4 and CO2) that are thought to have been utilized in the earliest metabolisms. Of particular importance for the emergence of metabolism are the mineral "chimneys" that precipitate at the vent fluid / seawater interface. Hydrothermal chimneys are flow-through chemical reactors that form porous and permeable inorganic membranes transecting geochemical gradients; in some ways similar to biological membranes that transect proton / ion gradients and harness these disequilibria to drive metabolism. These emergent chimney structures in the far-from-equilibrium system of the alkaline vent have many properties of interest to the origin of life that can be simulated in the laboratory: for example, they can generate electrical energy and drive redox reactions, and produce catalytic minerals (in particular the metal sulfides and iron oxyhydroxides - "green rust") that can facilitate chemical reactions towards proto-metabolic cycles and biosynthesis. Many of the factors prompting interest in alkaline hydrothermal vents on Earth may also have been present on early Mars, or even presently within icy worlds such as Europa or Enceladus - thus, understanding the disequilibria and resulting prebiotic chemistry in these systems can be of great use in assessing the potential for other environments in the Solar System where life could have emerged.

1. PERSPECTIVE VIEW FROM NORTHWEST OF NORTH SIDE. LOW BUILDING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. PERSPECTIVE VIEW FROM NORTHWEST OF NORTH SIDE. LOW BUILDING IN CENTER IS A SIGNAL POWER GENERATING STATION (C. 1986). LOW TOWER STRUCTURE ON THE LEFT IS ANCHOR BRIDGE NUMBER 310, LOCATION OF POWER FEED TO THE CATENARY SYSTEM. - New York, New Haven & Hartford Railroad, Cos Cob Power Plant, Sound Shore Drive, Greenwich, Fairfield County, CT

Single stage high pressure centrifugal slurry pump

DOEpatents

Meyer, John W.; Bonin, John H.; Daniel, Arnold D.

1984-03-27

Apparatus is shown for feeding a slurry to a pressurized housing. An impeller that includes radial passages is mounted in the loose fitting housing. The impeller hub is connected to a drive means and a slurry supply means which extends through the housing. Pressured gas is fed into the housing for substantially enveloping the impeller in a bubble of gas.

75 FR 42698 - Takes of Marine Mammals Incidental to Specified Activities; Installation of Meteorological Data...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-22

... driving could disturb normal marine mammal behaviors (e.g., feeding, social interactions), mask calls from... highly social and typical group size can range from the tens to hundreds and may reach up to 1,200... contexts and use sound for various biological functions including, but not limited to: (1) Social...

Fluid temperatures: Modeling the thermal regime of a river network

Treesearch

Rhonda Mazza; Ashley Steel

2017-01-01

Water temperature drives the complex food web of a river network. Aquatic organisms hatch, feed, and reproduce in thermal niches within the tributaries and mainstem that comprise the river network. Changes in water temperature can synchronize or asynchronize the timing of their life stages throughout the year. The water temperature fluctuates over time and place,...

Chronic High Fat Diet Consumption Impairs Metabolic Health of Male Mice

PubMed Central

Morselli, Eugenia; Criollo, Alfredo; Rodriguez-Navas, Carlos; Clegg, Deborah J.

2015-01-01

We show that chronic high fat diet (HFD) feeding affects the hypothalamus of male but not female mice. In our study we demonstrate that palmitic acid and sphingolipids accumulate in the central nervous system of HFD-fed males. Additionally, we show that HFD-feeding reduces proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) thus reducing estrogen receptor α (ERα) and driving hypothalamic inflammation in male but not female mice. Hypothalamic inflammation correlates with markers of metabolic dysregulation as indicated by dysregulation in glucose intolerance and myocardial function. Lastly, we demonstrate that there are blockages in mitophagy and lipophagy in hypothalamic tissues in males. Our data suggest there is a sexually dimorphic response to chronic HDF exposure, females; despite gaining the same amount of body weight following HFD-feeding, appear to be protected from the adverse metabolic effects of the HFD. PMID:26046098

Chronic High Fat Diet Consumption Impairs Metabolic Health of Male Mice.

PubMed

Morselli, Eugenia; Criollo, Alfredo; Rodriguez-Navas, Carlos; Clegg, Deborah J

We show that chronic high fat diet (HFD) feeding affects the hypothalamus of male but not female mice. In our study we demonstrate that palmitic acid and sphingolipids accumulate in the central nervous system of HFD-fed males. Additionally, we show that HFD-feeding reduces proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) thus reducing estrogen receptor α (ERα) and driving hypothalamic inflammation in male but not female mice. Hypothalamic inflammation correlates with markers of metabolic dysregulation as indicated by dysregulation in glucose intolerance and myocardial function. Lastly, we demonstrate that there are blockages in mitophagy and lipophagy in hypothalamic tissues in males. Our data suggest there is a sexually dimorphic response to chronic HDF exposure, females; despite gaining the same amount of body weight following HFD-feeding, appear to be protected from the adverse metabolic effects of the HFD.

NASA's Software Bank (Cassegrain Feed System)

NASA Technical Reports Server (NTRS)

1991-01-01

When Scientific-Atlanta had to design a new Cassegrain antenna, they found that the COSMIC program, "Machine Design of Cassegrain Feed System" allowed for computer simulation of the antenna's performance enabling pre-construction changes to be made. Significant cost savings were effected by the program.

Designing a System for Computer-Assisted Instruction in Road Education: A First Evaluation.

ERIC Educational Resources Information Center

Garcia-Ros, Rafael; Montoro, Luis; Valero, Pedro; Bayarri, Salvador; Martinez, Tomas

1999-01-01

Describes SIVAS, a computer-based system for driver education based on visual simulation that was developed in Spain to support theoretical concepts about driving in driving schools. Explains how teachers can select pre-built scenarios related to driving lessons in order to make up a lecture. (Author/LRW)

14 CFR 27.923 - Rotor drive system and control mechanism tests.

Code of Federal Regulations, 2010 CFR

2010-01-01

... the position that will give maximum longitudinal cyclic pitch change to simulate forward flight. The... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Rotor drive system and control mechanism....923 Rotor drive system and control mechanism tests. (a) Each part tested as prescribed in this section...

Monotony of road environment and driver fatigue: a simulator study.

PubMed

Thiffault, Pierre; Bergeron, Jacques

2003-05-01

Studies have shown that drowsiness and hypovigilance frequently occur during highway driving and that they may have serious implications in terms of accident causation. This paper focuses on the task induced factors that are involved in the development of these phenomena. A driving simulator study was conducted in order to evaluate the impact of the monotony of roadside visual stimulation using a steering wheel movement (SWM) analysis procedure. Fifty-six male subjects each drove during two different 40-min periods. In one case, roadside visual stimuli were essentially repetitive and monotonous, while in the other one, the environment contained disparate visual elements aiming to disrupt monotony without changing road geometry. Subject's driving performance was compared across these conditions in order to determine whether disruptions of monotony can have a positive effect and help alleviate driver fatigue. Results reveal an early time-on-task effect on driving performance for both driving periods and more frequent large SWM when driving in the more monotonous road environment, which implies greater fatigue and vigilance decrements. Implications in terms of environmental countermeasures for driver fatigue are discussed.

Road characteristics and driver fatigue: a simulator study.

PubMed

Oron-Gilad, Tal; Ronen, Adi

2007-09-01

Two experiments examined the influence of road characteristics on driver fatigue in a prolonged simulator drive. In experiment one, ten military truck drivers drove a mixed route, with straight, winding, and straight highway segments. In experiment two, 16 additional drivers drove either a straight, a winding, or a mixed route. Fatigue symptoms were assessed using performance, subjective, and psychophysiological measures (HRV). We hypothesized that drivers adopt different fatigue-coping strategies relative to the demands of the drive. Thus, on straight roads drivers are more likely to loosen their driving demands by either increasing their driving speed and/or not maintaining the lane position, as the road is tolerant to both strategies, whereas on winding roads, drivers are more likely to increase their speed but not their lane positioning. Our results confirm that decremental changes in driving performance varied among road types. In the straight road components, we found decrements in the quality of lane maintaining (experiment one) and steering quality (experiments one and two) and longitudinal speed (experiment two). In the winding road, we found that drivers increased their driving speed over time (experiments one and two).

Adams-Based Rover Terramechanics and Mobility Simulator - ARTEMIS

NASA Technical Reports Server (NTRS)

Trease, Brian P.; Lindeman, Randel A.; Arvidson, Raymond E.; Bennett, Keith; VanDyke, Lauren P.; Zhou, Feng; Iagnemma, Karl; Senatore, Carmine

2013-01-01

The Mars Exploration Rovers (MERs), Spirit and Opportunity, far exceeded their original drive distance expectations and have traveled, at the time of this reporting, a combined 29 kilometers across the surface of Mars. The Rover Sequencing and Visualization Program (RSVP), the current program used to plan drives for MERs, is only a kinematic simulator of rover movement. Therefore, rover response to various terrains and soil types cannot be modeled. Although sandbox experiments attempt to model rover-terrain interaction, these experiments are time-intensive and costly, and they cannot be used within the tactical timeline of rover driving. Imaging techniques and hazard avoidance features on MER help to prevent the rover from traveling over dangerous terrains, but mobility issues have shown that these methods are not always sufficient. ARTEMIS, a dynamic modeling tool for MER, allows planned drives to be simulated before commands are sent to the rover. The deformable soils component of this model allows rover-terrain interactions to be simulated to determine if a particular drive path would take the rover over terrain that would induce hazardous levels of slip or sink. When used in the rover drive planning process, dynamic modeling reduces the likelihood of future mobility issues because high-risk areas could be identified before drive commands are sent to the rover, and drives planned over these areas could be rerouted. The ARTEMIS software consists of several components. These include a preprocessor, Digital Elevation Models (DEMs), Adams rover model, wheel and soil parameter files, MSC Adams GUI (commercial), MSC Adams dynamics solver (commercial), terramechanics subroutines (FORTRAN), a contact detection engine, a soil modification engine, and output DEMs of deformed soil. The preprocessor is used to define the terrain (from a DEM) and define the soil parameters for the terrain file. The Adams rover model is placed in this terrain. Wheel and soil parameter files can be altered in the respective text files. The rover model and terrain are viewed in Adams View, the GUI for ARTEMIS. The Adams dynamics solver calls terramechanics subroutines in FORTRAN containing the Bekker-Wong equations.

Averaging of phase noise in PSK signals by an opto-electrical feed-forward circuit

NASA Astrophysics Data System (ADS)

Inoue, K.; Ohta, M.

2013-10-01

This paper proposes an opto-electrical feed-forward circuit that reduces phase noise in binary PSK signals by averaging the noise. Random and independent phase noise is averaged over several bit slots by externally modulating a phase-fluctuating PSK signal with feed-forward signal obtained from signal processing of the outputs of delay interferometers. The simulation results demonstrate a reduction in the phase noise.

Transfer of fat-soluble pesticides from contaminated feed to poultry tissues and eggs.

PubMed

MacLachlan, D J

2008-05-01

1. Implementation of Good Manufacturing Practice and HACCP (Hazard Analysis Critical Control Points) in the production of poultry feed requires efficient tools for profiling risks associated with pesticide use in the production of crops for feed. 2. This paper describes a simple model that may be of use in the first tiers of risk profiling of feeds. 3. The model adequately reproduced the pattern of residues in fat and eggs of laying hens dosed with a selection of lipophilic pesticides that may be used in the production of crops for poultry feeds: deltamethrin, diflubenzuron, fipronil, lindane, piperonyl butoxide and spinosad. 4. Simulations suggest results derived from studies on laying chickens can be extrapolated to other laying birds. 5. Poultry meat production systems focus on maximising growth of birds giving rise to significant potential for dilution of residues that transfer to fat from feed. 6. Simulations of residues in fat of chickens, ducks, geese and turkeys exposed to a lipophilic pesticide with an elimination half-life of one day at 10 mg/kg body weight/d from hatching to typical market ages suggest residues in fat that are highest in turkeys > chickens > geese > ducks. 7. The model is of use in interpreting published dosing studies and predicting likely residues in birds at times after last exposure/dosing.

Drivers who self-estimate lower blood alcohol concentrations are riskier drivers after drinking

PubMed Central

Laude, Jennifer R.; Fillmore, Mark T.

2016-01-01

Rationale Alcohol increases the tendency for risky driving in some individuals, but not others. Little is known about the factors underlying this individual difference. Studies find that those who underestimate their blood alcohol concentration (BAC) following a dose of alcohol tend to be more impulsive and report greater willingness to drive after drinking than those who estimate their BACs to be greater than their actual BAC. BAC underestimation could contribute to risky driving behavior following alcohol as such drivers might perceive little impairment in their driving ability and thus no need for caution. Objectives This study was designed to test the relationship between drivers’ BAC estimations following a dose of alcohol or a placebo and the degree of risky driving they displayed during a simulated driving test. Methods Forty adult drivers performed a simulated driving test and estimated their blood alcohol concentration after receiving a dose of alcohol (0.65 g/kg for men; 0.56 g/kg for women) or a placebo. . Results Alcohol increased risk taking and impaired driving skill. Those who estimated their BAC to be lower were the riskiest drivers following both alcohol and placebo. Conclusions The tendency to estimate lower BACs could support a series of high-risk decisions, regardless of one’s actual BAC. This could include the decision to drive after drinking. PMID:26861796