1,019 research outputs found

    Jirim kuark - mikroskopi elektron attoskala ke atas proton

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    We review experiments colliding electrons(/positrons) on protons at high energies at HERA, focussing on the ZEUS experiment. We describe the ZEUS detector, including its data acquisition system, and look at a specific part, namely the electronic system for its calorimeter readout control, in more detail. Data analysis is described, and results pertaining the proton structure is given. It is found that the naive quark model cannot explain the results obtained at small fractional momentum, and this requires quantum chromodynamics. Also it is found that diffractive reactions, with large rapidity gaps, contribute substantially; efforts are being carried out to understand them.Comment: "Quark matter - attoscale electron microscopy of the proton". In Malay. Invited plenary paper at Persidangan Fizik Kebangsaan (PERFIK) 2007, Pulau Duyong, Kuala Terengganu, Malaysia, 26-28 December 2007. Shortened English version available from autho

    Self-organizing map (SOM) for species distribution modelling of birds species at Kenyir landscape

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    Identifying which biodiversity species are more dominant than others in any area is a very challenging task. This is because of the abundant of biodiversity species that may become the majority species in any particular region. This situation create a large dataset with a complex variables to be analysed. Moreover, the responds of organisms and environmental factors are occurred in a non-linear correlation. The effort to do so is really important in order to conserve the biodiversity of nature. To understand the complex relationships that exist between species distribution and their habitat, we analysed the interactions among bird diversity, spatial distribution and land use types at Kenyir landscape in Terengganu, Malaysia by using artificial neural network (ANN) method of self-organizing map (SOM) analysis. SOM performs an unsupervised and non-linear analysis on a complex and large dataset. It is capable to handle the non-linear correlation between organism and environmental factors because SOM identifies clusters and relationships between variables without the fixed assumptions of linearity or normality. The result suggested that SOM analysis was suited for understanding the relationships between bird species assemblages and habitat characteristics