236 research outputs found

    Serial search for fingers of the same hand but not for fingers of different hands

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    In most haptic search tasks, tactile stimuli are presented to the fingers of both hands. In such tasks, the search pattern for some object features, such as the shape of raised line symbols, has been found to be serial. The question is whether this search is serial over all fingers irrespective of the hand, or whether it is serial over the fingers of each hand and parallel over the two hands. To investigate this issue, we determined the speed of static haptic search when two items are presented to two fingers of the same hand and when two items are presented to two fingers of different hands. We compared the results with predictions for parallel and serial search based on the results of a previous study using the same items and a similar task. The results indicate that two fingers of the same hand process information in a serial manner, while two fingers of two different hands process information in parallel. Thus, considering the individual fingers as independent units in haptic search may not be justified, because the hand that they belong to matters. © 2009 Springer-Verlag

    Haptic search with finger movements: using more fingers does not necessarily reduce search times

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    Two haptic serial search tasks were used to investigate how the separations between items, and the number of fingers used to scan them, influence the search time and search strategy. In both tasks participants had to search for a target (cross) between a fixed number of non-targets (circles). The items were placed in a straight line. The target’s position was varied within blocks, and inter-item separation was varied between blocks. In the first experiment participants used their index finger to scan the display. As expected, search time depended on target position as well as on item separation. For larger separations participants’ movements were jerky, resembling ‘saccades’ and ‘fixations’, while for the shortest separation the movements were smooth. When only considering time in contact with an item, search times were the same for all separation conditions. Furthermore, participants never continued their movement after they encountered the target. These results suggest that participants did not use the time during which they were moving between the items to process information about the items. The search times were a little shorter than those in a static search experiment (Overvliet et al. in Percept Psychophys, 2007a), where multiple items were presented to the fingertips simultaneously. To investigate whether this is because the finger was moving or because only one finger was stimulated, we conducted a second experiment in which we asked participants to put three fingers in line and use them together to scan the items. Doing so increased the time in contact with the items for all separations, so search times were presumably longer in the static search experiment because multiple fingers were involved. This may be caused by the time that it takes to switch from one finger to the other

    Interventions for Long Term Software Security:Creating a Lightweight Program of Assurance Techniques for Developers

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    Though some software development teams are highly effective at delivering security, others either do not care or do not have access to security experts to teach them how. Unfortunately, these latter teams are still responsible for the security of the systems they build: systems that are ever more important to ever more people. We propose that a series of lightweight interventions, six hours of facilitated workshops delivered over three months, can improve a team’s motivation to consider security and awareness of assurance techniques, changing its security culture even when no security experts are involved. The interventions were developed after an Appreciative Inquiry and Grounded Theory survey of security professionals to find out what approaches work best. We tested the interventions in a Participatory Action Research field study where we delivered the workshops to three soft- ware development organizations, and evaluated their effectiveness through interviews be- forehand, immediately afterwards, and after twelve months. We found that the interventions can be effective with teams with limited or no security experience, and that improvement is long lasting. This approach and the learning points arising from the work here have the potential to be applied in many development teams, improving the security of software worldwide

    Grasping Kinematics from the Perspective of the Individual Digits: A Modelling Study

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    Grasping is a prototype of human motor coordination. Nevertheless, it is not known what determines the typical movement patterns of grasping. One way to approach this issue is by building models. We developed a model based on the movements of the individual digits. In our model the following objectives were taken into account for each digit: move smoothly to the preselected goal position on the object without hitting other surfaces, arrive at about the same time as the other digit and never move too far from the other digit. These objectives were implemented by regarding the tips of the digits as point masses with a spring between them, each attracted to its goal position and repelled from objects' surfaces. Their movements were damped. Using a single set of parameters, our model can reproduce a wider variety of experimental findings than any previous model of grasping. Apart from reproducing known effects (even the angles under which digits approach trapezoidal objects' surfaces, which no other model can explain), our model predicted that the increase in maximum grip aperture with object size should be greater for blocks than for cylinders. A survey of the literature shows that this is indeed how humans behave. The model can also adequately predict how single digit pointing movements are made. This supports the idea that grasping kinematics follow from the movements of the individual digits

    Communication style and exercise compliance in physiotherapy (CONNECT). A cluster randomized controlled trial to test a theory-based intervention to increase chronic low back pain patients’ adherence to physiotherapists’ recommendations: study rationale, design, and methods

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    Physical activity and exercise therapy are among the accepted clinical rehabilitation guidelines and are recommended self-management strategies for chronic low back pain. However, many back pain sufferers do not adhere to their physiotherapist’s recommendations. Poor patient adherence may decrease the effectiveness of advice and home-based rehabilitation exercises. According to self-determination theory, support from health care practitioners can promote patients’ autonomous motivation and greater long-term behavioral persistence (e.g., adherence to physiotherapists’ recommendations). The aim of this trial is to assess the effect of an intervention designed to increase physiotherapists’ autonomy-supportive communication on low back pain patients’ adherence to physical activity and exercise therapy recommendations. \ud \ud This study will be a single-blinded cluster randomized controlled trial. Outpatient physiotherapy centers (N =12) in Dublin, Ireland (population = 1.25 million) will be randomly assigned using a computer-generated algorithm to either the experimental or control arm. Physiotherapists in the experimental arm (two hospitals and four primary care clinics) will attend eight hours of communication skills training. Training will include handouts, workbooks, video examples, role-play, and discussion designed to teach physiotherapists how to communicate in a manner that promotes autonomous patient motivation. Physiotherapists in the waitlist control arm (two hospitals and four primary care clinics) will not receive this training. Participants (N = 292) with chronic low back pain will complete assessments at baseline, as well as 1 week, 4 weeks, 12 weeks, and 24 weeks after their first physiotherapy appointment. Primary outcomes will include adherence to physiotherapy recommendations, as well as low back pain, function, and well-being. Participants will be blinded to treatment allocation, as they will not be told if their physiotherapist has received the communication skills training. Outcome assessors will also be blinded. \ud \ud We will use linear mixed modeling to test between arm differences both in the mean levels and the rates of change of the outcome variables. We will employ structural equation modeling to examine the process of change, including hypothesized mediation effects. \ud \ud This trial will be the first to test the effect of a self-determination theory-based communication skills training program for physiotherapists on their low back pain patients’ adherence to rehabilitation recommendations. Current Controlled Trials ISRCTN63723433\u
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