5 resultados para basis of the solution space of a homogeneous sparse linear system
em Digital Commons at Florida International University
Resumo:
Smaller class sizes have a positive impact on student achievement but Florida struggles with the problem of how to achieve smaller classes. Through a review of the literature, this paper discusses some of the programs currently used across the US, with the focus on Florida. Conclusions and implications are presented.
Resumo:
Since 1999, Venezuela has experienced a dramatic transformation of its political system with the coming to power of Hugo Chávez and his movement, known in Venezuela as Chavismo. Chávez has dismantled the previous political system and established neo-populist structures that rely on his personal appeal and the close collaboration of the armed forces. Chávez has relied heavily on significant support from the poor and those who felt economically and politically excluded by the “Punto Fijo system.” President Chávez has built an impressive record of electoral victories; winning every electoral contest except one since coming to power in 1999. He continues to receive relatively high levels of support among sectors of Venezuelan society. However, there is evidence of growing discontent with high crime rates, high levels of inflation, and significant corruption in the public administration. Using data from the AmericasBarometer surveys conducted in 2007, 2008 and 2010, this paper seeks to examine the basis of Chávez’s popular support. In general, the AmericasBarometer findings suggest that Venezuelans support for President Chávez is closely linked to the access to social programs and that as long as the government is able to fund these social programs or missions, particularly MERCAL and Barrio Adentro, it will possess an important tool to garner and sustain support for President Chávez. Our analysis, however, also indicates that evaluations of the national economic situation, more than crime or insecurity, are a key factor that could undermine support for the regime.
Resumo:
Iridescent blue leaf coloration in four Malaysian rain forest understory plants, Diplazium tomentosum Bl. (Athyriaceae), Lindsaea lucida Bl. (Lindsaeaceae), Begonia pavonina Ridl. (Begoniaceae), and Phyllagathis rotundifolia Bl. (Melastomataceae) is caused by a physical effect, constructive interference of reflected blue light. The ultrastructural basis for this in D. tomentosum and L. lucida is multiple layers of cellulose microfibrils in the uppermost cell walls of the adaxial epidermis. The helicoidal arrangement of these fibrils is analogous to that which produces a similar color in arthropods. In B. pavonina and P. rotundifolia the blue-green coloration is caused by parallel lamellae in specialized plastids adjacent to the abaxial wall of the adaxial epidermis. The selective advantage of this color production, if any, is unknown.
Resumo:
Iridescent blue leaf coloration in two neotropical ferns, Danaea nodosa (L.) Sm. (Marattiaceae) and Trichomanes elegans L. C. Rich. (Hymenophyllaceae), is caused by thin film constructive interference. The ultrastructural basis for the film in D. nodosa is multiple layers of cellulose microfibrils in the adaxial cell walls of the adaxial epidermis. The apparent helicoidal arrangement of the fibrils is analogous to similar color production in arthropods. In T. elegans the blue-green coloration is caused by the remarkably uniform thickness and arrangement of grana in specialized chloroplasts adjacent to the adaxial wall of the adaxial epidermis. The selective advantage of this color production, if any, is unknown but apparently different from that previously studied in Selaginella.
Resumo:
The major barrier to practical optimization of pavement preservation programming has always been that for formulations where the identity of individual projects is preserved, the solution space grows exponentially with the problem size to an extent where it can become unmanageable by the traditional analytical optimization techniques within reasonable limit. This has been attributed to the problem of combinatorial explosion that is, exponential growth of the number of combinations. The relatively large number of constraints often presents in a real-life pavement preservation programming problems and the trade-off considerations required between preventive maintenance, rehabilitation and reconstruction, present yet another factor that contributes to the solution complexity. In this research study, a new integrated multi-year optimization procedure was developed to solve network level pavement preservation programming problems, through cost-effectiveness based evolutionary programming analysis, using the Shuffled Complex Evolution (SCE) algorithm.^ A case study problem was analyzed to illustrate the robustness and consistency of the SCE technique in solving network level pavement preservation problems. The output from this program is a list of maintenance and rehabilitation treatment (M&R) strategies for each identified segment of the network in each programming year, and the impact on the overall performance of the network, in terms of the performance levels of the recommended optimal M&R strategy. ^ The results show that the SCE is very efficient and consistent in the simultaneous consideration of the trade-off between various pavement preservation strategies, while preserving the identity of the individual network segments. The flexibility of the technique is also demonstrated, in the sense that, by suitably coding the problem parameters, it can be used to solve several forms of pavement management programming problems. It is recommended that for large networks, some sort of decomposition technique should be applied to aggregate sections, which exhibit similar performance characteristics into links, such that whatever M&R alternative is recommended for a link can be applied to all the sections connected to it. In this way the problem size, and hence the solution time, can be greatly reduced to a more manageable solution space. ^ The study concludes that the robust search characteristics of SCE are well suited for solving the combinatorial problems in long-term network level pavement M&R programming and provides a rich area for future research. ^