The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform

Ramesh Sharda - One of the best experts on this subject based on the ideXlab platform.

  • Should I send this message? Understanding the impact of interruptions, social hierarchy and perceived task complexity on user performance and perceived workload
    Decision Support Systems, 2013
    Co-Authors: Ashish Gupta, Han Li, Ramesh Sharda
    Abstract:

    Instant messenger technologies have become a common place for collaborative work and group decision support. Managers need to understand the potential impact of using IM in an organization. This paper contributes to the literature on instant messaging and primary task performance by theorizing and empirically testing how the interruption frequency of IM could intertwine with the social characteristics of IM communication and jointly influence user task performance and perceived workload. Using experimental design, we found that the effect of interruption on primary task completion time is dependent upon the Hierarchical Level of the message sender. Interruptions from a supervisor were found to reduce primary task completion time whereas interruptions from a peer increased primary task completion time. On the other hand, interruptions from a supervisor aggravated the negative impact of interruptions on task quality. Thus, it may be important for members and leaders of group decision teams to be more careful in the use of instant messaging with their peers and subordinates.

Edwin Blake - One of the best experts on this subject based on the ideXlab platform.

  • Hierarchical Level of detail optimization for constant frame rate rendering of radiosity scenes : research article
    South African Computer Journal, 2002
    Co-Authors: Shaun Nirenstein, Edwin Blake, Simon Winberg, Ashton E. W. Mason
    Abstract:

    The predictive Hierarchical Level of detail optimization algorithm of Mason and Blake is experimentally evaluated in the form of a practical application to Hierarchical radiosity. In a novel approach the recursively subdivided patch hierarchy generated by a perceptually refined Hierarchical radiosity algorithm is treated as a Hierarchical Level of detail scene description. In this way we use the Mason-Blake algorithm to successfully maintain constant frame rates during the interactive rendering of the radiosity-generated scene. We establish that the algorithm is capable of maintaining uniform frame rendering times, but that the execution time of the optimization algorithm itself is significant and is strongly dependent on frame-to-frame coherence and the granularity of the Level of detail description. To compensate we develop techniques which effectively reduce and limit the algorithm execution time: We restrict the execution times of the algorithm to guard against pathological situations and propose simplification transforms that increase the granularity of the scene description, at minimal cost to visual quality. We demonstrate that using these techniques the algorithm is capable of maintaining interactive frame rates for scenes of arbitrary complexity. Furthermore we provide guidelines for the appropriate use of predictive Level of detail optimization algorithms derived from our practical experience.

  • Hierarchical Level of Detail Optimization for Constant Frame Rate Rendering of Radiosity Scenes
    South African Computer Journal, 2002
    Co-Authors: Shaun Nirenstein, Edwin Blake, Simon Winberg, Ashton E. W. Mason
    Abstract:

    The predictive Hierarchical Level of detail optimization algorithm of Mason and Blake is experimentally evaluated in the form of a practical application to Hierarchical radiosity. In a novel approach the recursively subdivided patch hierarchy generated by a perceptually refined Hierarchical radiosity algorithm is treated as a Hierarchical Level of detail scene description. In this way we use the Mason-Blake algorithm to successfully maintain constant frame rates during the interactive rendering of the radiosity-generated scene. We establish that the algorithm is capable of maintaining uniform frame rendering times, but that the execution time of the optimization algorithm itself is significant and is strongly dependent on frame-to-frame coherence and the granularity of the Level of detail description. To compensate we develop techniques which effectively reduce and limit the algorithm execution time: We restrict the execution times of the algorithm to guard against pathological situations and propose simplification transforms that increase the granularity of the scene description, at minimal cost to visual quality. We demonstrate that using these techniques the algorithm is capable of maintaining interactive frame rates for scenes of arbitrary complexity. Furthermore we provide guidelines for the appropriate use of predictive Level of detail optimization

  • A graphical representation of the state spaces of Hierarchical Level-of-detail scene descriptions
    IEEE Transactions on Visualization and Computer Graphics, 2001
    Co-Authors: Ashton E. W. Mason, Edwin Blake
    Abstract:

    We present a new graphical representation of the Level-of-detail state spaces generated by Hierarchical geometric scene descriptions with multiple Levels of detail. These Level-of-detail graphs permit the analytical investigation of the Hierarchical Level-of-detail optimization problem that arises for such descriptions. As an example of their use, we prove the equivalence of two Hierarchical Level-of-detail algorithms.

  • Automatic Hierarchical Level of Detail Optimization in Computer Animation
    Computer Graphics Forum, 1997
    Co-Authors: Ashton E. W. Mason, Edwin Blake
    Abstract:

    We show that the Hierarchical Level of detail optimization problem is equivalent to a constrained version of the Multiple Choice Knapsack Problem, and present a new algorithm whose solution to it is at least half as good as the optimal one. The advantage of the Hierarchical algorithm is that it allows the use of Hierarchical Level of detail descriptions in which shared representations may be provided for groups of objects. Rendering cost may then be saved to afford better renderings of more important objects, and the algorithm is capable of providing a complete representation of the visible scene even when the visible scene complexity is very high. Our algorithm has a worst case time complexity of O nlogn , and is incremental so that it typically completes in only a few iterations. We introduce the use of perceptual evaluation to demonstrate the effectiveness of the use of representations for groups of objects that our algorithm allows.

Ashton E. W. Mason - One of the best experts on this subject based on the ideXlab platform.

  • Hierarchical Level of detail optimization for constant frame rate rendering of radiosity scenes : research article
    South African Computer Journal, 2002
    Co-Authors: Shaun Nirenstein, Edwin Blake, Simon Winberg, Ashton E. W. Mason
    Abstract:

    The predictive Hierarchical Level of detail optimization algorithm of Mason and Blake is experimentally evaluated in the form of a practical application to Hierarchical radiosity. In a novel approach the recursively subdivided patch hierarchy generated by a perceptually refined Hierarchical radiosity algorithm is treated as a Hierarchical Level of detail scene description. In this way we use the Mason-Blake algorithm to successfully maintain constant frame rates during the interactive rendering of the radiosity-generated scene. We establish that the algorithm is capable of maintaining uniform frame rendering times, but that the execution time of the optimization algorithm itself is significant and is strongly dependent on frame-to-frame coherence and the granularity of the Level of detail description. To compensate we develop techniques which effectively reduce and limit the algorithm execution time: We restrict the execution times of the algorithm to guard against pathological situations and propose simplification transforms that increase the granularity of the scene description, at minimal cost to visual quality. We demonstrate that using these techniques the algorithm is capable of maintaining interactive frame rates for scenes of arbitrary complexity. Furthermore we provide guidelines for the appropriate use of predictive Level of detail optimization algorithms derived from our practical experience.

  • Hierarchical Level of Detail Optimization for Constant Frame Rate Rendering of Radiosity Scenes
    South African Computer Journal, 2002
    Co-Authors: Shaun Nirenstein, Edwin Blake, Simon Winberg, Ashton E. W. Mason
    Abstract:

    The predictive Hierarchical Level of detail optimization algorithm of Mason and Blake is experimentally evaluated in the form of a practical application to Hierarchical radiosity. In a novel approach the recursively subdivided patch hierarchy generated by a perceptually refined Hierarchical radiosity algorithm is treated as a Hierarchical Level of detail scene description. In this way we use the Mason-Blake algorithm to successfully maintain constant frame rates during the interactive rendering of the radiosity-generated scene. We establish that the algorithm is capable of maintaining uniform frame rendering times, but that the execution time of the optimization algorithm itself is significant and is strongly dependent on frame-to-frame coherence and the granularity of the Level of detail description. To compensate we develop techniques which effectively reduce and limit the algorithm execution time: We restrict the execution times of the algorithm to guard against pathological situations and propose simplification transforms that increase the granularity of the scene description, at minimal cost to visual quality. We demonstrate that using these techniques the algorithm is capable of maintaining interactive frame rates for scenes of arbitrary complexity. Furthermore we provide guidelines for the appropriate use of predictive Level of detail optimization

  • A graphical representation of the state spaces of Hierarchical Level-of-detail scene descriptions
    IEEE Transactions on Visualization and Computer Graphics, 2001
    Co-Authors: Ashton E. W. Mason, Edwin Blake
    Abstract:

    We present a new graphical representation of the Level-of-detail state spaces generated by Hierarchical geometric scene descriptions with multiple Levels of detail. These Level-of-detail graphs permit the analytical investigation of the Hierarchical Level-of-detail optimization problem that arises for such descriptions. As an example of their use, we prove the equivalence of two Hierarchical Level-of-detail algorithms.

  • Automatic Hierarchical Level of Detail Optimization in Computer Animation
    Computer Graphics Forum, 1997
    Co-Authors: Ashton E. W. Mason, Edwin Blake
    Abstract:

    We show that the Hierarchical Level of detail optimization problem is equivalent to a constrained version of the Multiple Choice Knapsack Problem, and present a new algorithm whose solution to it is at least half as good as the optimal one. The advantage of the Hierarchical algorithm is that it allows the use of Hierarchical Level of detail descriptions in which shared representations may be provided for groups of objects. Rendering cost may then be saved to afford better renderings of more important objects, and the algorithm is capable of providing a complete representation of the visible scene even when the visible scene complexity is very high. Our algorithm has a worst case time complexity of O nlogn , and is incremental so that it typically completes in only a few iterations. We introduce the use of perceptual evaluation to demonstrate the effectiveness of the use of representations for groups of objects that our algorithm allows.

William D'hoore - One of the best experts on this subject based on the ideXlab platform.

  • Leadership styles across Hierarchical Levels in nursing departments.
    Nursing research, 2000
    Co-Authors: Sabine Stordeur, Christian Vandenberghe, William D'hoore
    Abstract:

    BACKGROUND: Some researchers have reported on the cascading effect of transformational leadership across Hierarchical Levels. One study examined this effect in nursing, but it was limited to a single hospital. OBJECTIVES: To examine the cascading effect of leadership styles across Hierarchical Levels in a sample of nursing departments and to investigate the effect of Hierarchical Level on the relationships between leadership styles and various work outcomes. METHODS: Based on a sample of eight hospitals, the cascading effect was tested using correlation analysis. The main sources of variation among leadership scores were determined with analyses of variance (ANOVA), and the interaction effect of Hierarchical Level and leadership styles on criterion variables was tested with moderated regression analysis. RESULTS: No support was found for a cascading effect of leadership across Hierarchical Levels. Rather, the variation of leadership scores was explained primarily by the organizational context. Transformational leadership had a stronger impact on criterion variables than transactional leadership. Interaction effects between leadership styles and Hierarchical Level were observed only for perceived unit effectiveness. CONCLUSIONS: The hospital's structure and culture are major determinants of leadership styles.

Stephan E. Wolf - One of the best experts on this subject based on the ideXlab platform.

  • Structural commonalities and deviations in the Hierarchical organization of crossed-lamellar shells: A case study on the shell of the bivalve Glycymeris glycymeris
    Journal of Materials Research, 2016
    Co-Authors: Corinna F. Böhm, Benedikt Demmert, Joe Harris, Tobias Fey, Frédéric Marin, Stephan E. Wolf
    Abstract:

    The structural organization of the palliostracum—the dominant part of the shell which is formed by the mantle cells—of Glycymeris glycymeris (Linné 1758) is comprised of five Hierarchical Levels with pronounced structural commonalities and deviations from other crossed-lamellar shells. The Hierarchical Level known as second order lamellae, present within other crossed-lamellar shells, is absent highlighting a short-coming of the currently used nomenclature. On the mesoscale, secondary microtubules penetrate the palliostracum and serve as crack arrestors. Moreover, the growth lamellae follow bent trajectories possibly impacting crack propagation, crack deflection, and energy dissipation mechanisms whilst circumventing delamination. Finally, at least two structural elements are related to external circatidal and circaanular stimuli. This emphasizes that endogeneous rhythms may contribute and (co-)control the self-organization of a complex mineralized tissue and that it is insufficient to rely fully on a reductionistic approach when studying biomineralization.