Optimization Analysis (optimization + analysis)

Distribution by Scientific Domains


Selected Abstracts


Dynamic operation plan of a combined fuel cell cogeneration, solar module, and geo-thermal heat pump system using Genetic Algorithm

INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 13 2007
Shin'ya Obara
Abstract A chromosome model that simulates the operation patterns of an energy system was introduced into a simple Genetic Algorithm, and a method of dynamic optimization was developed. This paper analyses the operation planning of an energy system that uses in combination a solar power module, proton-exchange membrane fuel cell cogeneration (PEMFC-CGS) with methanol steam reforming, a geo-thermal heat pump, heat storage and battery, commercial power, and a kerosene boiler. The hours of operation of each energy device and the rate of the energy output were calculated by having introduced the analysis program developed by this study. Three objective functions: (a) minimization of operation cost; (b) minimization of the error of demand-and-supply balance; and (c) minimization of the amount of greenhouse gas discharge were given to the optimization analysis of the system. Furthermore, the characteristics of the system operation planning under each objective function are described. Copyright © 2007 John Wiley & Sons, Ltd. [source]


A phylogeny of Vetigastropoda and other "archaeogastropods": re-organizing old gastropod clades

INVERTEBRATE BIOLOGY, Issue 3 2010
Stephanie W. Aktipis
Abstract. The phylogenetic relationships among the "archaeogastropod" clades Patellogastropoda, Vetigastropoda, Neritimorpha, and Neomphalina are uncertain; the phylogenetic placement of these clades varies across different analyses, and particularly among those using morphological characteristics and those relying on molecular data. This study explores the relationships among these groups using a combined analysis with seven molecular loci (18S rRNA, 28S rRNA, histone H3, 16S rRNA, cytochrome c oxidase subunit I [COI], myosin heavy-chain type II, and elongation factor-1, [EF-1,]) sequenced for 31 ingroup taxa and eight outgroup taxa. The deep evolutionary splits among these groups have made resolution of stable relationships difficult, and so EF-1, and myosin are used in an attempt to re-examine these ancient radiation events. Three phylogenetic analyses were performed utilizing all seven genes: a single-step direct optimization analysis using parsimony, and two-step approaches using parsimony and maximum likelihood. A single-step direct optimization parsimony analysis was also performed using only five molecular loci (18S rRNA, 28S rRNA, histone H3, 16S rRNA, and COI) in order to determine the utility of EF-1, and myosin in resolving deep relationships. In the likelihood and POY optimal phylogenetic analyses, Gastropoda, Caenogastropoda, Neritimorpha, Neomphalina, and Patellogastropoda were monophyletic. Additionally, Neomphalina and Pleurotomariidae fell outside the remaining vetigastropods, indicating the need for further investigation into the relationship of these groups with other gastropods. [source]


Plant traits and functional types in response to reduced disturbance in a semi-natural grassland

JOURNAL OF VEGETATION SCIENCE, Issue 2 2005
F. Louault
Abstract. Question: How do functional types respond to contrasting levels of herbage use in temperate and fertile grasslands? Location: Central France (3°1'E, 45°43'N), 870 m a.s.l. Methods: Community structure and the traits of dominant plant species were evaluated after 12 years of contrasted grazing and mowing regimes in a grazing trial, comparing three levels of herbage use (high, medium and low). Results and Conclusions: Of 22 measured traits (including leaf traits, shoot morphology and composition, phenology), seven were significantly affected by the herbage use treatment. A decline in herbage use reduced individual leaf mass, specific leaf area and shoot digestibility, but increased leaf C and dry matter contents. Plants were taller, produced larger seeds and flowered later under low than high herbage use. Nine plant functional response types were identified by multivariate optimization analysis; they were based on four optimal traits: leaf dry matter content, individual leaf area, mature plant height and time of flowering. In the high-use plots, two short and early flowering types were co-dominant, one competitive, grazing-tolerant and moderately grazing-avoiding, and one grazing-avoiding but not -tolerant. Low-use plots were dominated by one type, neither hardly grazing-avoiding nor grazing-tolerant, but strongly competitive for light. [source]


A phylogeny of megachiropteran bats (Mammalia: Chiroptera: Pteropodidae) based on direct optimization analysis of one nuclear and four mitochondrial genes

CLADISTICS, Issue 6 2003
Norberto P Giannini
The phylogeny of megachiropteran bats (Mammalia: Chiroptera: Pteropodidae) has been investigated using several different molecular datasets. These studies differed widely in taxonomic and locus sampling, and their results tended to lack resolution of internal nodes and were themselves largely incongruent. To address this, we assembled a data set of 5 loci (up to 3.5 kbp from 12S rDNA, 16S rDNA, tDNA-valine, cytochrome b, and the nuclear gene c -mos) for 43 species of megachiropterans and 6 microchiropteran outgroups. We analyzed these data with direct optimization under equal costs for substitutions and indels. We used POY in a parallel setting, and searches consisted of replicated swapping + refinements (ratcheting, tree fusing, and iterative pass optimization). Our results indicate that Megachiroptera and all recognized genera (including Pteropus) are monophyletic, and that Melonycteris is the sister group of the clade containing all the other genera. Clades previously proposed using molecular data, as well as many new and traditional groups, were well-supported, and various sources suggest that the degree of conflict with morphological data may be considerably less marked than previously supposed. Analysis of individual loci suffer 70% loss in the number of compatible groups recovered across all analyses with respect to combined analyses. Our results indicate that, within Megachiroptera, nectarivory and cave-dwelling originated several times, but echolocation (used for obstacle detection) evolved only once. Megachiropterans likely originated in SE Asia-Melanesia, and colonized Africa at least four times. [source]