1,629 research outputs found

    Variable Frequency Drive (VFD) Specifications for Irrigation District Pumps

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    This information was compiled by ITRC and includes specifications for standards, warranties, submittals, VFD size, and other technical details to aid districts in the selection and implementation of VFD system

    Variable Frequency Drive (VFD) Specifications for On-Farm Pumps

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    This document applies to Variable Frequency Drive (VFD) system installations meeting all of the following criteria: The project owner or authorized representative is applying to participate in the PG&E Agricultural Pumping VFD Incentive Program, which involves a rebate for a complete VFD system, rather than components. This project involves a VFD system designed to control the speed of a 60 Hz alternating current motor that is rated for: 480VAC or less 600 HP or less The VFD-controlled motor will be used specifically for pumping agricultural irrigation water into a pressurized irrigation system

    ShapeFit and ShapeKick for Robust, Scalable Structure from Motion

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    We introduce a new method for location recovery from pair-wise directions that leverages an efficient convex program that comes with exact recovery guarantees, even in the presence of adversarial outliers. When pairwise directions represent scaled relative positions between pairs of views (estimated for instance with epipolar geometry) our method can be used for location recovery, that is the determination of relative pose up to a single unknown scale. For this task, our method yields performance comparable to the state-of-the-art with an order of magnitude speed-up. Our proposed numerical framework is flexible in that it accommodates other approaches to location recovery and can be used to speed up other methods. These properties are demonstrated by extensively testing against state-of-the-art methods for location recovery on 13 large, irregular collections of images of real scenes in addition to simulated data with ground truth

    Friendly Fire in a Simulated Firearms Task

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    Factors such as poor visibility, lack of situation awareness and bad communication have been shown to contribute to friendly fire incidents. However, to the authors’ knowledge, an individual’s ability to inhibit their motor response of shooting when a non-target is presented has not been investigated. This phenomenon has been modeled empirically using the Sustained Attention to Response Task (SART; Robertson, Manly, Andrade, Baddeley, & Yiend, 1997) computer task. The SART is generally a high Go/low No-Go detection task whereby participants respond to numerous neutral stimuli and withhold to rare targets. In the current investigation, we further investigate the SART using a simulated small arms scenario to test whether lack of motor response inhibition can be modeled in a more ecologically valid environment. Additionally, we were interested in how error rates were impacted in low Go/high No-Go versions of the task. Thirteen university students completed a computer and simulated small arms scenario in a SART and low Go condition. Both the computer and small arms scenario revealed similar speed-accuracy trade-offs indicating participants’ inability to halt their pre-potent responses to targets even in a more ecologically valid environment. The SART may be used in future studies to model friendly fire scenarios

    Cyber Threats Facing Autonomous and Connected Vehicles: Future Challenges

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    Vehicles are currently being developed and sold with increasing levels of connectivity and automation. As with all networked computing devices, increased connectivity often results in a heightened risk of a cyber security attack. Furthermore, increased automation exacerbates any risk by increasing the opportunities for the adversary to implement a successful attack. In this paper, a large volume of publicly accessible literature is reviewed and compartmentalised based on the vulnerabilities identified and mitigation techniques developed. This review highlighted that the majority of research is reactive and vulnerabilities are often discovered by friendly adversaries (white-hat hackers). Many gaps in the knowledge base were identified. Priority should be given to address these knowledge gaps to minimise future cyber security risks in the connected and autonomous vehicle sector

    Spider Stimuli Improve Response Inhibition

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    Anxiety can have positive effects on some aspects of cognition and negative effects on others. The current study investigated whether task-relevant anxiety could improve peo- ple’s ability to withhold responses in a response inhibition task. Sixty-seven university stu- dents completed a modified and an unmodified version of the Sustained Attention to Response Task (SART; Robertson, Manly, Andrade, Baddeley, & Yiend, 1997) and provided subjective measures of arousal and thoughts. Anxiety appeared to improve participants’ ability to withhold responses. Further, participants’ performance was consistent with a motor response inhibition perspective rather than a mind-wandering perspective of SART commission error performance. Errors of commission were associated with response times (speed-accuracy trade-off) as opposed to task-unrelated thoughts. Task-related thoughts were associated with the speed-accuracy trade-off. Conversely task-unrelated thoughts showed an association with errors of omission, suggesting this SART metric could be an indicator of sustained attention. Further investigation of the role of thoughts in the SART is warranted

    Human Factors Issues in Using Micro-Uninhabited Vehicles in Urban Disasters

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    Technical advances in remotely operated vehicles (drones) have seen an increase in their use in a variety of work settings, including remote searches and damage assessment. In the case of disaster response and management, uninhabited aerial vehicles (UAVs) could be extremely useful. For example in floods UAVs could be used to search for people trapped on roofs or floating on debris, in bushfires they could be used to improve the view of the fire and provided response managers with improved situational awareness, in marine environments UAVs could be used to search for lost people, and finally, in earthquakes UAVs could be used, if small enough, to search within buildings for damage assessment and searches. In the later case, this has already been attempted in response to the Christchurch February 22nd earthquakes, in which a Parrot A.R quadrocopter drone (commercial off-the-shelf drone) was flown into the Christchurch Cathedral in order to assess for damage. This idea radically reduces the risk to search and damage assessment personnel. However, actually flying the micro-UAV presents a significant challenge in these kinds of environments. In the present talk, we will discuss recent research at the University of Canterbury on human factors issues of using micro-UAVs in urban disaster scenarios. One of the challenges in flying micro-UAVs is that the pilot has limited sensory information. The pilot is flying with a limited field of view, a 2-d camera image instead of a 3-d naturalistic scene (out of a cockpit window), and the pilot receives no tactile or vestibular cues regarding the UAV’s orientation. One significant challenge in using micro-UAVs, therefore, in urban settings is operating the drone in constrained environments, for example, inside buildings. The turbulence and tight spacing of these environments presents a significant challenge to the pilot. We have been examining the issues involved in using micro-UAVs in these constrained environments. We will discuss training programs for pilots, motor control aspects of the piloting task, the relative costs and benefits of different control interfaces, and assessments of the cognitive workload of the piloting task. In the later research we have added a secondary mental workload to the pilot. This technique is called dual-tasking and it enables a sensitive assessment of the actual mental workload of a primary task. We had pilots engage in a piloting task and a secondary communication-like task. The secondary task represented communication with a co-worker and required the pilot to recall verbally transmitted words presented to the pilot during the flight operation. The pilots navigated and controlled the drone in simulated search operations (flying an obstacle course). We used the secondary task to assess the cognitive load of the flight task. In comparison to other simple motor tasks such as using a joystick to select targets on a computer screen the UAV piloting task is extremely demanding. We will also discuss future planned research

    Human factors issues with the use of text-speak communication

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    Advances in communication technology have significantly changed how individuals communicate (Crystal, 2008). Individuals not only have auditory communication at the their disposal, but also text based communication available through cell phones or computers. Emergency response agencies have begun to utilize text messaging to warn people of impending natural disasters (Samarajiva & Waidvanatha, 2009). These early warning systems can likely save lives by allowing people to prepare accordingly. Text messaging may also be useful in actual emergency management operations, such as disaster response. In these settings, text based communication could be more beneficial than auditory communication in that it allows an individual to reread a message a later time; text messages serve as an augmentation to human memory which is fallible. For example, civil defense personnel could receive a text message in which details are critical (e.g., survivors on third floor of bank near stairway). Once the message is received, one can reread the message and extract key information that could potentially save lives. One potential problem with text messaging is the limited amount of space available and time it takes to write. To overcome limited amount of space the time limits, individuals incorporate shortening techniques (i.e., text-speak) that allows an individual to convey a word or phrase in a shorter amount of time and decreased amount of space (e.g., srvvrs on 3rd flor of bnk near th strwy, survivors on the third floor of the bank near the stairway). Although text-speak allows one to create a message faster and in a shorter amount of space, processing text-speak could exact a cognitive cost to the reader (Head, et al., 2012). It is likely that civil defense workers responding to natural disasters could be subject to processing text-speak while text messaging. For example, it is common for civil defense to use shortening techniques such as acronyms (e.g., EQC-earthquake commission, GEOC-Group Emergency Operations Centre and MoH-Ministry of Health)

    A Study to Determine if University Athletic Teams in Desert Environments Experience Risky Diet-related Behaviours

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    Training and competing in desert environments may exacerbate concerns related to disordered eating, supplement use, and hydration in some student athlete populations. A survey administered equitably to both genders solicited self-reported responses from members of 18 different teams over four years from a southwestern United States university athletic program. More than 1,700 athletes responded to 42 items on the questionnaire. Teams, not individual student athletes, were the units of measure for statistical analyses. Initial analysis of results indicated that there were no overt concerns regarding dietary behaviors due to training and competing in the desert environment. Further analysis subjected the team responses to principle component factor analysis and determined the construct validity using Varimax rotation with Kaiser normalization. Six factors were identified which accounted for 93% of total variance associated with reported risky dietary related behaviors among athletic teams. Specifically, the factors contributing to dietary related behavior total variance were; 1) weight loss and exercise issues and practices -47.15%, 2) self-image - 26.00%, 3) hydration - 10.92%, 4) supplement use - 3.85%, 5) disordered eating - 3.70%, and 6) hormonal issues - 1.71%. University athletic programs should use routine assessment of dietary related behaviours, including hydration, to help identify team members practicing risky dietary related behaviours

    Obesity: transition from adolescence to adulthood and feedback partial gmm logistic model with time-dependent covariates

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    Background: The aim of this study is to investigate the impact of certain covariates on obesity. More importantly, we seek to determine the feedback of obesity on depression, and physical activity as they transition from adolescence to young adulthood. Methods: Using 15 years of nationally representative data from 6560 adolescents (Add health data), we estimate feedback and associations between depression, and activity scale on obesity while we adjusted for gender, age, race/ethnicity, socioeconomic status through a GMM logistic regression model with time-dependent covariates. Results: Activity (p<0.001) and depression (p<0.001) have significant impact on Obesity. In early years, alcohol had no impact (p=0.895 and p=0.476) on obesity but in later years it did (p<0.001). In the early years, television hours had an impact but as they got older, it did not. Conclusion: Our findings suggest that public health researchers can target obesity simultaneously with depression, and activity scale. These findings contribute new insights into the feedback of obesity on depression, and activity. This unique model allows segments of associations to be addressed rather than assuming all associations remain the same over 15 years.&nbsp
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