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Larger System (larger + system)
Selected AbstractsDispersal and life span spectra in plant communities: a key to safe site dynamics, species coexistence and conservationECOGRAPHY, Issue 2 2002Roel J. Strykstra Dispersal and life span of individual plant species within five plant communities were assessed to obtain a characterization of these communities in this respect. Such a characterization is important in the context of restoration and maintenance. The most frequent species of five communities were ranked in eight classes according to their level of seed dispersal capability, their seed bank formation (dispersal in time and space) and their individual life span. In the communities, all eight classes were found, but communities differed in the distribution of the species over the classes. A theoretical framework was constructed to use the level of specialization of plant species in terms of dispersal in space and time, and life span, to define the characteristics of safe site dynamics within communities. Following simple rules, the relative reliability of the occurrence of safe sites in space and time was defined. After that, the relative reliability of the habitat was linked to the best fitting combination of trait specialization level. Having defined this link, communities could be characterized in a comparative way by their level and pattern of reliability of the opportunities for recruitment in space and time. The meaning of the coexistence of a range of trait combinations in one community was discussed. It was postulated that habitat reliability can explain this by assuming that the habitat of the community is part of a larger system, or consists of several "subsystems". These insights need to be considered in nature conservation. Succession and also specializations beyond the scope of dispersal and life span may influence the occurrence of species in a seemingly unfit habitat (for instance the occurrence of semi parasitic annuals in a community of perennials, because they use the perennial root system of other species). Finally, the meaning of safe site reliability in space and time in the context of restoration of communities was discussed. The reliability in space and time may be different today from that of the past, which restricts the feasibility of restoration of communities. [source] Fast iterative solution of large undrained soil-structure interaction problemsINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 3 2003Kok-Kwang Phoon Abstract In view of rapid developments in iterative solvers, it is timely to re-examine the merits of using mixed formulation for incompressible problems. This paper presents extensive numerical studies to compare the accuracy of undrained solutions resulting from the standard displacement formulation with a penalty term and the two-field mixed formulation. The standard displacement and two-field mixed formulations are solved using both direct and iterative approaches to assess if it is cost-effective to achieve more accurate solutions. Numerical studies of a simple footing problem show that the mixed formulation is able to solve the incompressible problem ,exactly', does not create pressure and stress instabilities, and obviate the need for an ad hoc penalty number. In addition, for large-scale problems where it is not possible to perform direct solutions entirely within available random access memory, it turns out that the larger system of equations from mixed formulation also can be solved much more efficiently than the smaller system of equations arising from standard formulation by using the symmetric quasi-minimal residual (SQMR) method with the generalized Jacobi (GJ) preconditioner. Iterative solution by SQMR with GJ preconditioning also is more elegant, faster, and more accurate than the popular Uzawa method. Copyright © 2003 John Wiley & Sons, Ltd. [source] The Credit Hour and Faculty Instructional WorkloadNEW DIRECTIONS FOR HIGHER EDUCATION, Issue 122 2003Thomas Ehrlich The credit hour is the common metric for measuring faculty instructional workload and is a part of a larger system that makes innovation more difficult. [source] The disturbing student and the judicial processNEW DIRECTIONS FOR STUDENT SERVICES, Issue 128 2009John D. Ragle In the context of a larger system such as the AISP model, the judicial process can respond to the disturbing student in a manner that is constructive for the student as well as for the campus community. [source] Major Innovation as a Dynamic Capability: A Systems Approach,THE JOURNAL OF PRODUCT INNOVATION MANAGEMENT, Issue 4 2008Gina Colarelli O'Connor Major innovation (MI), composed of both radical and really new innovation, is an important mechanism for enabling the growth and renewal of an enterprise. Yet it is poorly managed in most established firms, and success stories are rare. This conceptual article draws on systems theory, recent advances in dynamic capabilities theory, and the management of innovation literature to offer a framework for building an MI dynamic capability. The framework is composed of seven elements that together form a management system rather than a process-based approach to nurturing radical innovation. These system elements are (1) an identifiable organization structure; (2) interface mechanisms with the mainstream organization, some of which are tightly coupled and others of which are loose; (3) exploratory processes; (4) requisite skills and talent development, given that entrepreneurial talent is not present in most organizations; (5) governance and decision-making mechanisms at the project, MI portfolio, and MI system levels; (6) appropriate performance metrics; and (7) an appropriate culture and leadership context. It is argued that dynamic capabilities for phenomena as complex as MI must be considered in a systems fashion rather than as operating routines and repeatable processes as the literature currently suggests. A set of propositions is offered regarding how each element should play out in this parallel management system. Finally, each element's role in the major innovation system is justified in terms of four criteria required by systems theory: (1) The system is identifiable, and its elements are interdependent; (2) the effect of the whole is greater than the sum of the parts; (3) homeostasis is achieved through interaction and networking with the larger organization; and (4) there is a clear purpose in the larger system in which the MI management system is embedded. Examples are given to demonstrate these criteria. Systems theory offers a new way of thinking about dynamic capability development and management. [source] Quantitative Phase Field Modeling of Precipitation Processes,ADVANCED ENGINEERING MATERIALS, Issue 12 2006Q. Bronchard Phase Field modelling of microstructural evolution in alloys has already a long and successful history. One of the basics of the theory is the introduction of continuous fields (concentration, long-range order parameters) that describe the local state of the alloy. These fields have a meaning only at a mesoscopic scale. One consequence is that we can treat much larger systems than with microscopic methods such as Monte Carlo or molecular dynamics simulations. The aim of this work is to precisely analyse the status of the mesoscopic free energy densities that are used in Phase Field theories and, simultaneously, to clarify the form that the Phase Field equations should adopt. [source] Fast fragments: The development of a parallel effective fragment potential methodJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 15 2004Heather M. Netzloff Abstract The Effective Fragment Potential (EFP) method for solvation decreases the cost of a fully quantum mechanical calculation by dividing a chemical system into an ab initio region that contains the solute plus some number of solvent molecules, if desired, and an "effective fragment" region that contains the remaining solvent molecules. Interactions introduced with this fragment region (for example, Coulomb and polarization interactions) are added as one-electron terms to the total system Hamiltonian. As larger systems and dynamics are just starting to be studied with the EFP method, more needs to be done to decrease the calculation time of the method. This article considers parallelization of both the EFP fragment-fragment and mixed quantum mechanics (QM)-EFP interaction energy and gradient computation within the GAMESS suite of programs. The iteratively self-consistent polarization term is treated with a new algorithm that makes use of nonblocking communication to obtain better scalability. Results show that reasonable speedup is achieved with a variety of sizes of water clusters and number of processors. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 1926,1935, 2004 [source] Aluminium-27 NMR investigation of the influence of cation type on aluminosilicate solutionsMAGNETIC RESONANCE IN CHEMISTRY, Issue 10 2002Naser Azizi Abstract The effects of tetraalkylammonium (TAA) and alkali metal cations on the equilibrium distribution of aluminosilicate oligomers in aqueous alkaline aluminosilicate solutions were investigated using 27Al NMR spectra and their evolution with time. The results indicate that there are no differences in the initial equilibria involving solutions containing both TAA and alkali metal cations on the one hand and those containing alkali metal cations only. However, re-equilibration of the aluminosilicate species for TAA/Na aluminosilicates is slow (usually not detectable on the time-scale of the experiments), whereas when purely alkali metal cations are used, the spectra alter over a period of ,1 h, such that resolution is degraded substantially. In the latter case, it is suggested that the anions aggregate into larger systems, although the solutions are still clear. 29Si NMR evidence for slow equilibration of silicate and aluminosilicate solutions at higher concentrations is also discussed. Copyright © 2002 John Wiley & Sons, Ltd. [source] Robustness of efficient server assignment policies to service time distributions in finite-buffered linesNAVAL RESEARCH LOGISTICS: AN INTERNATIONAL JOURNAL, Issue 6 2010Eser K, zlar Abstract We study the assignment of flexible servers to stations in tandem lines with service times that are not necessarily exponentially distributed. Our goal is to achieve optimal or near-optimal throughput. For systems with infinite buffers, it is already known that the effective assignment of flexible servers is robust to the service time distributions. We provide analytical results for small systems and numerical results for larger systems that support the same conclusion for tandem lines with finite buffers. In the process, we propose server assignment heuristics that perform well for systems with different service time distributions. Our research suggests that policies known to be optimal or near-optimal for Markovian systems are also likely to be effective when used to assign servers to tasks in non-Markovian systems. © 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010 [source] Defining Systems Expertise: Effective Simulation at the Organizational Level,Implications for Patient Safety, Disaster Surge Capacity, and Facilitating the Systems InterfaceACADEMIC EMERGENCY MEDICINE, Issue 11 2008Amy H. Kaji MD Abstract The Institute of Medicine's report "To Err is Human" identified simulation as a means to enhance safety in the medical field, just as flight simulation is used to improve the aviation industry. Yet, while there is evidence that simulation may improve task performance, there is little evidence that simulation actually improves patient outcome. Similarly, simulation is currently used to model teamwork-communication skills for disaster management and critical events, but little research or evidence exists to show that simulation improves disaster response or facilitates intersystem or interagency communication. Simulation ranges from the use of standardized patient encounters to robot-mannequins to computerized virtual environments. As such, the field of simulation covers a broad range of interactions, from patient,physician encounters to that of the interfaces between larger systems and agencies. As part of the 2008 Academic Emergency Medicine Consensus Conference on the Science of Simulation, our group sought to identify key research questions that would inform our understanding of simulation's impact at the organizational level. We combined an online discussion group of emergency physicians, an extensive review of the literature, and a "public hearing" of the questions at the Consensus Conference to establish recommendations. The authors identified the following six research questions: 1) what objective methods and measures may be used to demonstrate that simulator training actually improves patient safety? 2) How can we effectively feedback information from error reporting systems into simulation training and thereby improve patient safety? 3) How can simulator training be used to identify disaster risk and improve disaster response? 4) How can simulation be used to assess and enhance hospital surge capacity? 5) What methods and outcome measures should be used to demonstrate that teamwork simulation training improves disaster response? and 6) How can the interface of systems be simulated? We believe that exploring these key research questions will improve our understanding of how simulation affects patient safety, disaster surge capacity, and intersystem and interagency communication. [source] | |||||||||||||