1,085,805 research outputs found

    A piloted simulator investigation of stability and control, display and crew-loading requirements for helicopter instrument approach. Part 1: Technical discussion and results

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    A ground-simulation experiment was conducted to investigate the influence and interaction of flight-control system, fight-director display, and crew-loading situation on helicopter flying qualities during terminal area operations in instrument conditions. The experiment was conducted on the Flight Simulator for Advanced Aircraft at Ames Research Center. Six levels of control complexity, ranging from angular rate damping to velocity augmented longitudinal and vertical axes, were implemented on a representative helicopter model. The six levels of augmentation were examined with display variations consisting of raw elevation and azimuth data only, and of raw data plus one-, two-, and three-cue flight directors. Crew-loading situations simulated for the control-display combinations were dual-pilot operation (representative auxiliary tasks of navigation, communications, and decision-making). Four pilots performed a total of 150 evaluations of combinations of these parameters for a representative microwave landing system (MLS) approach task

    Subjective rating scales as a workload

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    A multidimensional bipolar-adjective rating scale is employed as a subjective measure of operator workload in the performance of a one-axis tracking task. The rating scale addressed several dimensions of workload, including cognitive, physical, and perceptual task loading as well as fatigue and stress effects. Eight subjects performed a one-axis tracking task (with six levels of difficulty) and rated these tasks on several workload dimensions. Performance measures were tracking error RMS (root-mean square) and the standard deviation of control stick output. Significant relationships were observed between these performance measures and skill required, task complexity, attention level, task difficulty, task demands, and stress level

    Lessons Learned from Efforts at Institutional Change: Case Studies of Six OCEPT Institutions

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    As one part of a multifaceted evaluation of the Oregon Collaborative for Excellence in the Preparation of Teachers (OCEPT), a case study approach was used to enable a deeper understanding of how a diverse group of six institutions attempted to achieve OCEPT goals and to learn more about factors that facilitated or hindered their efforts. Multiple sources of data were used, with heavy reliance on a series of on-site interviews. The analytical framework included a depth and pervasiveness typology of institutional change and a view of change as encompassing meaning, organization, and effects. While goals and accomplishment levels, as well as the depth and pervasiveness of change. varied across the six institutions, OCEPT-influenced changes most likely to be sustained included: new kinds and levels of faculty collaboration; peer-led teaching and learning approaches, and attention to evidence that these approaches positively affect student course performance; increased faculty awareness of their role in teacher recruitment, with related changes in classroom practices; and, continued strengthening of access to infomiation and academic advising for those preparing to become teachers. These institutions, however, did not make significant progress on one major goal of the project—to increase the numbers of underrepresented groups interested in teaching careers. Change was affected by the compatibility of OCEPT goals with institutional and faculty culture, as well as by local collaborative leadership, the size and complexity of the institution, the presence of boundary spanners, and how OCEPT resources were used

    Managing the entanglement: complexity leadership in public sector systems

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    Complexity in public sector systems requires leaders to balance the administrative practices necessary to be aligned and efficient in the management of routine challenges and the adaptive practices required to respond to dynamic circumstances. Conventional notions of leadership in the field of public administration do not fully explain the role of leadership in balancing the entanglement of formal, top-down, administrative functions and informal, emergent, adaptive functions within public sector settings with different levels of complexity. Drawing on and extending existing complexity leadership constructs, this article explores how leadership is enacted over the duration of six urban regeneration projects representing high, medium, and low levels of project complexity. The article suggests that greater attention needs to be paid to the tensions inherent in enabling leadership if actors are to cope with the complex, collaborative, cross-boundary, adaptive work in which they are increasingly engage

    Determining the essential characetristics of Six Sigma Black Belts

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    A Six Sigma Black Belt (SSBB) plays the role of a full-time team leader responsible for implementing process improvement projects using the Six Sigma methodology (Define-Measure-Analyse-Improve-Control) within the business to drive up customer satisfaction levels and business productivity. Black Belt projects are typically defined so that they can be completed in less than 6 months, and are generally focused on high-priority business issues and are targeted to add 175,000to175,000 to 250,000 to the bottom-line of organisations (Snee, 2004). A fully trained BB will be expected to deliver a minimum of 500,000towellover500,000 to well over 1,000,000 in direct cost savings to the bottom-line of an organisation per year (Harry and Schroeder, 2000). Moreover, a BB is expected to complete between 4 to 6 projects per annum depending on the scope of the project, complexity of the project and availability of data. The BB program of study focuses on an understanding of the Six Sigma philosophy, key principles and concepts, tactics, application of tools and techniques, project management skills, etc. So,why the martial arts terminology? The sole function of a BB is to focus on disciplined problem solving using the DMAIC (Define-Measure-Analyse-Improve-Control) methodology and a specific set of tools and techniques with speed (i.e. project completion in a short period of time). The purpose here is to defeat the enemy – variation in processes which lead to customer dissatisfaction (Brue and Howes, 2006)

    Synchrony, complexity and directiveness in mothers\u27 interactions with infants pre- and post-cochlear implantation

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    This study investigated effects of profound hearing loss on mother–infant interactions before and after cochlear implantation with a focus on maternal synchrony, complexity, and directiveness. Participants included two groups of mother–infant dyads: 9 dyads of mothers and infants with normal hearing; and 9 dyads of hearing mothers and infants with profound hearing loss. Dyads were observed at two time points: Time 1, scheduled to occur before cochlear implantation for infants with profound hearing loss (mean age = 13.6 months); and Time 2 (mean age = 23.3 months), scheduled to occur approximately six months after cochlear implantation. Hearing infants were age-matched to infants with hearing loss at both time points. Dependent variables included the proportion of maternal utterances that overlapped infant vocalizations, maternal mean length of utterance, infant word use, and combined maternal directives and prohibitions. Results showed mothers’ utterances overlapped the vocalizations of infants with hearing loss more often before cochlear implantation than after, mothers used less complex utterances with infants with cochlear implants compared to hearing peers (Time 2), and mothers of infants with profound hearing loss used frequent directives and prohibitions both before and after cochlear implantation. Together, mothers and infants adapted relatively quickly to infants’ access to cochlear implants, showing improved interactional synchrony, increased infant word use, and levels of maternal language complexity compatible with infants’ word use, all within seven months of cochlear implant activation

    Effects of Contact Network Models on Stochastic Epidemic Simulations

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    The importance of modeling the spread of epidemics through a population has led to the development of mathematical models for infectious disease propagation. A number of empirical studies have collected and analyzed data on contacts between individuals using a variety of sensors. Typically one uses such data to fit a probabilistic model of network contacts over which a disease may propagate. In this paper, we investigate the effects of different contact network models with varying levels of complexity on the outcomes of simulated epidemics using a stochastic Susceptible-Infectious-Recovered (SIR) model. We evaluate these network models on six datasets of contacts between people in a variety of settings. Our results demonstrate that the choice of network model can have a significant effect on how closely the outcomes of an epidemic simulation on a simulated network match the outcomes on the actual network constructed from the sensor data. In particular, preserving degrees of nodes appears to be much more important than preserving cluster structure for accurate epidemic simulations.Comment: To appear at International Conference on Social Informatics (SocInfo) 201
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