2,798 research outputs found

    Optimization Of Fuzzy Evapotranspiration Model Through Neural Training With Input–Output Examples

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    In a previous study, we demonstrated that fuzzy evapotranspiration (ET) models can achieve accurate estimation of daily ET comparable to the FAO Penman–Monteith equation, and showed the advantages of the fuzzy approach over other methods. The estimation accuracy of the fuzzy models, however, depended on the shape of the membership functions and the control rules built by trial–and–error methods. This paper shows how the trial and error drawback is eliminated with the application of a fuzzy–neural system, which combines the advantages of fuzzy logic (FL) and artificial neural networks (ANN). The strategy consisted of fusing the FL and ANN on a conceptual and structural basis. The neural component provided supervised learning capabilities for optimizing the membership functions and extracting fuzzy rules from a set of input–output examples selected to cover the data hyperspace of the sites evaluated. The model input parameters were solar irradiance, relative humidity, wind speed, and air temperature difference. The optimized model was applied to estimate reference ET using independent climatic data from the sites, and the estimates were compared with direct ET measurements from grass–covered lysimeters and estimations with the FAO Penman–Monteith equation. The model–estimated ET vs. lysimeter–measured ET gave a coefficient of determination (r2) value of 0.88 and a standard error of the estimate (Syx) of 0.48 mm d–1. For the same set of independent data, the FAO Penman–Monteith–estimated ET vs. lysimeter–measured ET gave an r2 value of 0.85 and an Syx value of 0.56 mm d–1. These results show that the optimized fuzzy–neural–model is reasonably accurate, and is comparable to the FAO Penman–Monteith equation. This approach can provide an easy and efficient means of tuning fuzzy ET models

    Communication Competence: A Commentary

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    There have been many attempts to identify communication competence by communication scholars. Many attempts in determining definitions have focused on action definitions (speaker-defined competence) and reaction definitions (listener defined competence). In agreeing that communication is transactional, communication competence should be held to the same standard. Communication competence must be viewed as a joint effort by all participants in a situation; not as solely dependent on the communicator or the listener). Public speaking evaluation forms attempt to measure communication competence of the speaker only. A recent attempt is The Competent Speaker Speech Evaluation Form (1992). This form identifies 8 competencies for the public speaker. These competencies offer the same problems to users that other forms have. These include: (1) the discrimination of the different levels of competence, (2) the subjective judgments from the teacher\u27s point of view to the audience as a whole, and (3) the cultural narrowness of the descriptions of the competencies

    Summary of Issues Discussed During the Seminar on the Introductory Course in Speech Communication, November 1990

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    The introductory course in communication has received considerable attention by scholars and practitioners in the past several years. Conventions, workshops and scholarly journals reflect the concerns of course directors, teachers and administrators in defining, operating and evaluating this course. Fourteen faculty convened at the SCA Annual Convention in San Francisco in November 1990 to identify and discuss the major issues relevant to directing and teaching the introductory course in communication. Five major issues were identified during the seminar. Discussion of the issues ranged from theoretical perspectives to specific action steps. This report is a summary of some of the major conclusions reached by the participants of the seminar

    Turf Investigations for Airports and Highways

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    Magic Numbers for the Photoelectron Anisotropy in Li-Doped Dimethyl Ether Clusters

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    Photoelectron velocity map imaging of Li(CH3_3OCH3_3)n_n clusters (1 ≤\leq n ≤\leq 175) is used to search for magic numbers related to the photoelectron anisotropy. Comparison with density functional calculations reveals magic numbers at n=4, 5, and 6, resulting from the symmetric charge distribution with high s-character of the highest occupied molecular orbital. Since each of these three cluster sizes correspond to the completion of a first coordination shell, they can be considered as 'isomeric motifs of the first coordination shell'. Differences in the photoelectron anisotropy, the vertical ionization energies and the enthalpies of vaporization between Li(CH3_3OCH3_3)n_n and Na(CH3_3OCH3_3)n_n can be rationalized in terms of differences in their solvation shells, atomic ionization energies, polarizabilities, metal-oxygen bonds, ligand-ligand interactions, and by cooperative effects

    Developmental and tissue-specific expression of NITRs

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    Novel immune-type receptors (NITRs) are encoded by large multi-gene families and share structural and signaling similarities to mammalian natural killer receptors (NKRs). NITRs have been identified in multiple bony fish species, including zebrafish, and may be restricted to this large taxonomic group. Thirty-nine NITR genes that can be classified into 14 families are encoded on zebrafish chromosomes 7 and 14. Herein, we demonstrate the expression of multiple NITR genes in the zebrafish ovary and during embryogenesis. All 14 families of zebrafish NITRs are expressed in hematopoietic kidney, spleen and intestine as are immunoglobulin and T cell antigen receptors. Furthermore, all 14 families of NITRs are shown to be expressed in the lymphocyte lineage, but not in the myeloid lineage, consistent with the hypothesis that NITRs function as NKRs. Sequence analyses of NITR amplicons identify known alleles and reveal additional alleles within the nitr1, nitr2, nitr3, and nitr5 families, reflecting the recent evolution of this gene family

    Asteroids in the Inner Solar System I - Existence

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    Ensembles of in-plane and inclined orbits in the vicinity of the Lagrange points of the terrestrial planets are integrated for up to 100 million years. The integrations incorporate the gravitational effects of Sun and the eight planets (Pluto is neglected). Mercury is the least likely planet, as it is unable to retain tadpole orbits over 100 million year timescales. Both Venus and the Earth are much more promising, as they possess rich families of stable tadpole and horseshoe orbits. Our survey of Trojans in the orbital plane of Venus is undertaken for 25 million years. Some 40% of the survivors are on tadpole orbits. For the Earth, the integrations are pursued for 50 million years. The stable zones in the orbital plane are larger for the Earth than for Venus, but fewer of the survivors are tadpoles. Both Venus and the Earth also have regions in which inclined test particles can endure near the Lagrange points. For Venus, only test particles close to the orbital plane are stable. For the Earth, there are two bands of stability, one at low inclinations (i < 16 degrees) and one at moderate inclinations (between 24 degrees and 34 degrees). The inclined test particles that evade close encounters are primarily moving on tadpole orbits. Our survey of in-plane test particles near the Martian Lagrange points shows no survivors after 60 million years. Low inclination test particles do not persist, as their inclinations are quickly increased until the effects of a secular resonance with Jupiter cause de-stabilisation. Numerical integrations of inclined test particles for timespans of 25 million years show stable zones for inclinations between 14 and 40 degrees.Comment: 20 pages, 21 figures, Monthly Notices (in press

    Removal of apple trees

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    Far from Home: A Qualitative Analysis of Altered Social and Familial Interactions by Students Attending College Significant Distances from Home

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    This study explored the necessary modifications for students’ relationships with their home contexts (social and familial) as they acclimated to college life. We specifically targeted students living over 1,000 miles from their present school setting. Thirty undergraduate students at a private Midwest university participated in this qualitative phenomenological research study through semistructured interviews. While numerous dynamics surfaced, repeated themes included feelings of homesickness, desiring to go home, weakening of peer relationships established at home, and gradual strengthening of familial relationships
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