2,727,437 research outputs found

    Space Chicken: A Historical Look at How the Critical Path Changes over a Missions Development

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    The critical path in schedule analysis defines the series of tasks that have no schedule slack leading to the delivery of a system. The critical path for NASA science missions, which typically runs through a spacecraft subsystem or a scientific instrument, is dynamic and changes over the development lifetime of a project. Often the critical path at the start of preliminary design will be through a specific spacecraft subsystem while the final, delivered critical path item is often a scientific instrument that is delivered late. The research for this paper looks at the postulated critical path at different milestones, and the actual critical path item at final delivery, for a variety of NASA science missions to understand what elements are impacting the delivery schedule the most. Recommendations are made based on these quantitative results relative to what elements should potentially be considered more often in early development schedules to more robustly plan for development issues

    Scaling up: A path to effective development

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    Poverty reduction, Hunger, MDGs, Interventions, Political dynamics, Capacity, Development assistance, Scaling up,

    A complex systems methodology to transition management

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    There is a general sense of urgency that major technological transitions are required for sustainable development. Such transitions are best perceived as involving multiple transition steps along a transition path. Due to the path dependent and irreversible nature of innovation in complex technologies, an initial transition step along some preferred path may cut off paths that later may turn out to be more desirable. For these reasons, initial transition steps should allow for future flexibility, where we define flexibility as robustness regarding changing evidence and changing preferences. We propose a technology assessment methodology that identifies the flexibility of initial transition steps in complex technologies. We illustrate our methodology by an empirical application to 2646 possible future car systems.NK-model, complexity, flexibility, irreversibility, path dependence, transition path, transition management, sustainable development, car technology

    Path space forms and surface holonomy

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    We develop parallel transport on path spaces from a differential geometric approach, whose integral version connects with the category theoretic approach. In the framework of 2-connections, our approach leads to further development of higher gauge theory, where end points of the path need not be fixed.Comment: 6 pages, 2 figures. Talk delivered by S. Chatterjee at XXVIII WGMP, 28th June-4th July, 2009. Bialowieza, Polan

    Development of path loss model for 802.11n in large conference rooms

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    In this paper, a path loss (PL) model for 802.11n in large conference rooms is determined, based on PL measurements. The PL can be described accurately by a one-slope model with one standard deviation. PL exponents varying from 1.2 to 1.7 are found. Based on this PL model, the effect of frequency (2.4 vs 5 GHz), configuration (SISO vs MIMO (spatial diversity)), bandwidth (20 vs 40 MHz) and transmit power on number of access points, total power consumption and possible (physical) throughputs is investigated. According to the determined PL model, a higher range (by tuning the transmit power) requires less access points, as well as a lower total power consumption, due to a PL exponent lower than 2

    Socio-technical paths and crossings in business development

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    In this paper an evolutionary model of business development is proposed, which links cooperationbetween organizations and their exchanges to path dependence and crossings.While the concept of path dependence restricts action to the exploitation of the existing path, theconcept of crossings emphasizes that within existing structures there are opportunities to take an otherpath. In a case study, over a period of twelve years the business development of a firm and itsevolving network relations are described. To find out if a firm can change is taken path, the conceptsof path dependence and crossings are explored along the cycle of development
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