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991.
Self-regulated learners are expected to plan their own learning. Because planning is a complex task, it is not self-evident that all learners can perform this task successfully. In this study, we examined the effects of two planning support tools on the quality of created plans, planning behavior, task load, and acquired knowledge. Sixty-five participants each worked with two versions of a planning tool. In one version, learning plans were actively constructed by the learners themselves; the other version provided learners with an adaptable computer-generated plan. The results indicated that the quality of learner-created plans was lower than computer-generated plans. Furthermore, participants reported a higher task load when they constructed the plans by themselves. However, participants gained more structural knowledge about the learning domain when they actively created plans. There was not an apparent preference for one of the tools if participants were to create a plan for someone else. However, if they were to use the plan for their own learning, participants preferred to actively create their own plans.  相似文献   
992.
Intelligent learning systems (ILSs) have evolved in the last few years basically because of influences received from multi-agent architectures (MAs). Conflict resolution among agents has been a very important problem for multi-agent systems, with specific features in the case of ILSs. The literature shows that ILSs with cognitive or pedagogical agents are prone to arbitration methods, where as ILSs with reactive agents are much in favor of control mechanisms. For these kind of systems, different control types are proposed based on the different stimuli that these agents will receive. These stimuli are aspects to be evaluated during the teaching/learning process such as: (1) error analysis, (2) learning styles, (3) analogies, (4) social aspects, etc.

The paper reviews several ILSs, related to our work; different control mechanisms are proposed to solve the agents' intervention conflicts. Finally, the use of several mechanisms is exemplified by the results of a specific ILS.  相似文献   
993.
Mechanical properties of wood at different length scales of its hierarchical structure are governed by structural and compositional properties on smaller length scales. This opens up the possibility to use microstructural data for estimating mechanical properties, which are difficult to assess by conventional, destructive testing but are nevertheless of high relevance for conservation practice. Herein, we investigate such microstructure-mechanics relationships for a particular example, namely the load bearing archaeological oak of the Oseberg Viking ship, displayed at the Viking Ship Museum in Oslo, Norway. In order to identify the effects of degradation on the mechanical behavior and their relations to the microstructure, recent oak specimens of different geographical origin (Norway and Austria) are investigated as well. Wood exhibits a cellular structure. Its cell walls are composed of an amorphous polymer matrix consisting of lignin and hemicelluloses and embedded, stiff cellulose fibers. At the cell level, experimental studies comprised microscopic investigations of the cellular structure, chemical analyses of the composition of the cell walls, as well as nanoindentation tests on single cell walls. The same samples were also analyzed on the macroscopic level, where additionally mass density and annual ring data were measured together with ultrasonic stiffnesses. The chemical data clearly indicate deterioration in the archaeological oak, affecting mainly hemicelluloses and amorphous cellulose. At the cell wall scale, however, this does not necessarily lead to a weaker material behavior. The nanoindentation modulus, as a measure of the cell wall stiffness, was found to even increase. This is counterintuitive to our understanding of the effects of chemical degradation. It might be due to possible modification of lignin in the Oseberg oak, and thus have a stronger effect on the indentation modulus than the concurrent weakening of the interfaces between the load-carrying cellulose fibers and the connecting cell wall matrix when analyzing wood at the microscopic level. A similar effect is also observed for the transversal stiffness of macroscopic samples, which increases. In tension-dominated loading modes, however, the degradation of the interfaces is the dominant effect, resulting for example in a considerable reduction of the macroscopic stiffness in longitudinal direction. This underlines the utmost relevance of the loading condition on the remaining load-carrying capacity of degraded wood. On the macroscale, effects of the geographical origin (i.e. growth conditions) on ring characteristics of the oak tissues override the effects of degradation on the mechanical behavior. They have to be carefully extracted in order to come up with conclusions on the effect of degradation from macroscopic test results. The identified microstructure-mechanics relationships provide the basis for–in further research steps–building mathematical models describing the relations between microstructural characteristics and macroscopic mechanical properties and, thereon, for structural analyses of historical wooden objects.  相似文献   
994.
This article places universal service policy in telecommunications in Australia in an historical context. Given the dynamic growth in information technologies, universal service should be reconceptualized within a knowledge-based discourse critically linked to considerations for deepening participatory democracy. As a consequence of the discussion this article recommends that funding universal service obligations in telecommunications be based on the preferred notion of a maximally open democratic debate. The universal service obligation in telecommunications should be funded from consolidated revenue with its parameters set by democratic debate.  相似文献   
995.
Management literature has identified high-skilled human capital as a crucial dimension of innovation processes at the firm level. In this study, we introduce an alternative view of human capital based on the tasks that firms’ workers perform. We propose a measure of cognitive analytical and interpersonal tasks: the degree of abstractism. We argue that the level of abstractism of a firm has an effect on a firm's propensity to innovate and on its product innovation performance. We hypothesize that while the degree of abstractism has a linear positive relationship with the propensity to innovate, the relationship between abstractism and product innovation performance follows an inverted u-shaped relationship. We find partial support to our hypotheses using data from more than six thousand Portuguese firms. We discuss how these results change our understanding of the relationship between human capital and innovation at the firm level.  相似文献   
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Trajectories of adjustment were examined in a sample of street-involved youth across a 1-year period. Participants (N = 113; Mage = 14.18 years; 80.5% male, 91% non-White) were recruited in three Brazilian cities. Interviews conducted at three time points included six measures of physical and psychological adjustment. Unconditional growth models revealed linear declines over time (i.e., improved adjustment) on three indicators: health symptoms, sexual risk behaviors, and negative affect. There were no linear changes in drug use, positive affect, or life satisfaction. Conditional growth models revealed few significant effects for age or gender, but ratings of stressful life events moderated longitudinal changes in health symptoms, drug use, and negative affect. Implications for practice, policy, and theory are discussed.  相似文献   
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