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Efficient Transmission (efficient + transmission)
Selected AbstractsOn-Line Control Architecture for Enabling Real-Time Traffic System OperationsCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 5 2004Srinivas Peeta Critical to their effectiveness are the control architectures that provide a blueprint for the efficient transmission and processing of large amounts of real-time data, and consistency-checking and fault tolerance mechanisms to ensure seamless automated functioning. However, the lack of low-cost, high-performance, and easy-to-build computing environments are key impediments to the widespread deployment of such architectures in the real-time traffic operations domain. This article proposes an Internet-based on-line control architecture that uses a Beowulf cluster as its computational backbone and provides an automated mechanism for real-time route guidance to drivers. To investigate this concept, the computationally intensive optimization modules are implemented on a low-cost 16-processor Beowulf cluster and a commercially available supercomputer, and the performance of these systems on representative computations is measured. The results highlight the effectiveness of the cluster in generating substantial computational performance scalability, and suggest that its performance is comparable to that of the more expensive supercomputer. [source] Vector within-host feeding preference mediates transmission of a heterogeneously distributed pathogenECOLOGICAL ENTOMOLOGY, Issue 3 2010MATTHEW P. DAUGHERTY 1. Ecological theory predicts that vector preference for certain host species or discrimination between infected versus uninfected hosts impacts disease incidence. However, little information exists on the extent to which vector within-host feeding preference mediates transmission. This may be particularly important for plant pathogens, such as sharpshooter transmission of the bacterium Xylella fastidiosa, which are distributed irregularly throughout hosts. 2. We documented the within-host distribution of two vector species that differ in transmission efficiency, the leafhoppers Draeculacephala minerva and Graphocephala atropunctata, and which are free to move throughout entirely caged alfalfa plants. The more efficient vector D. minerva fed preferentially at the base of the plant near the soil surface, whereas the less efficient G. atropunctata preferred overwhelming the top of the plant. 3. Next we documented X. fastidiosa heterogeneity in mechanically inoculated plants. Infection rates were up to 50% higher and mean bacterial population densities were 100-fold higher near the plant base than at the top or in the taproot. 4. Finally, we estimated transmission efficiency of the two leafhoppers when they were confined at either the base or top of inoculated alfalfa plants. Both vectors were inefficient when confined at the top of infected plants and were 20,60% more efficient when confined at the plant base. 5. These results show that vector transmission efficiency is determined by the interaction between leafhopper within-plant feeding behaviour and pathogen within-plant distribution. Fine-scale vector and pathogen overlap is likely to be a requirement generally for efficient transmission of vector-borne pathogens. [source] Fault-tolerant control of process systems using communication networksAICHE JOURNAL, Issue 6 2005Nael H. El-Farra Abstract A methodology for the design of fault-tolerant control systems for chemical plants with distributed interconnected processing units is presented. Bringing together tools from Lyapunov-based nonlinear control and hybrid systems theory, the approach is based on a hierarchical architecture that integrates lower-level feedback control of the individual units with upper-level logic-based supervisory control over communication networks. The local control system for each unit consists of a family of control configurations for each of which a stabilizing feedback controller is designed and the stability region is explicitly characterized. The actuators and sensors of each configuration are connected, via a local communication network, to a local supervisor that orchestrates switching between the constituent configurations, on the basis of the stability regions, in the event of failures. The local supervisors communicate, through a plant-wide communication network, with a plant supervisor responsible for monitoring the different units and coordinating their responses in a way that minimizes the propagation of failure effects. The communication logic is designed to ensure efficient transmission of information between units, while also respecting the inherent limitations in network resources by minimizing unnecessary network usage and accounting explicitly for the effects of possible delays due to fault-detection, control computations, network communication and actuator activation. The proposed approach provides explicit guidelines for managing the various interplays between the coupled tasks of feedback control, fault-tolerance and communication. The efficacy of the proposed approach is demonstrated through chemical process examples. © 2005 American Institute of Chemical Engineers AIChE J, 2005 [source] An effective system for detecting Iris yellow spot virus transmission by Thrips tabaciPLANT PATHOLOGY, Issue 3 2010T. Inoue A simple, effective and convenient laboratory leaf system was developed to detect transmission of Iris yellow spot virus (IYSV) by thrips. It was shown that IYSV was transmitted highly efficiently by adults and also by larvae of five thelytokous populations of Thripstabaci from distinct areas in Japan: over all these populations, transmission efficiency of adults ranged from 20·4% (19/93) to 41·1% (76/185) and that of larvae from 17·3% (14/81) to 44·1% (67/152). Finally, it was demonstrated that IYSV infection was not detrimental to the development and fecundity of thrips until early adulthood. Larval mortalities of virus-exposed thrips were higher than in their unexposed counterparts in all three populations, but the differences were not significant. The results demonstrated that T. tabaci populations have considerable potential to cause outbreaks of IYSV and spread the disease because of their efficient transmission of the virus. [source] Adaptation of the Fungal Parasite Zygorhizidium planktonicum During 200 Generations of Growth on Homogeneous and Heterogeneous Populations of Its Host, the Diatom Asterionella formosa,THE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 2 2008ARNOUT DE BRUIN ABSTRACT. We followed adaptation of the chytrid parasite Zygorhizidium planktonicum during 200 generations of growth on its host, the freshwater diatom Asterionella formosa, in a serial passage experiment. Evolution of parasite fitness was assessed both on a homogenous and heterogeneous host population, consisting of respectively a single new and ten different new host strains. These 10 host strains were genetically different and also varied in their initial susceptibility to the parasite. Parasite fitness increased significantly and rapidly on the new, genetically homogenous host population, but remained unaltered during 200 generations of growth on the heterogeneous host population. Enhanced parasite fitness was the result of faster and more efficient transmission, resulting in higher values of R0 (number of secondary infections). Consequently, parasites that evolved within the uniclonal host population infected significantly more of these hosts than did their ancestors. We thus provide experimental evidence for the widely held view that host genetic diversity restricts evolution of parasites and moderates their harmful effects. Genetically uniform host populations are not only at increased risk from fungal epidemics because they all share the same susceptibility, but also because new parasite strains are able to adapt quickly to new host environments and to improve their fitness. [source] Enhanced proliferation and efficient transmission of Candidatus Liberibacter asiaticus by adult Diaphorina citri after acquisition feeding in the nymphal stageANNALS OF APPLIED BIOLOGY, Issue 1 2009H. Inoue Abstract We carried out a quantitative detection of Candidatus Liberibacter asiaticus, the bacterium associated with the disease of huanglongbing, in the vector psyllid Diaphorina citri by using a TaqMan real-time PCR assay. The concentration of the bacterium was monitored at 5-day intervals for a period of 20 days after psyllids were exposed as fifth instar nymphs or adults to a Ca. L. asiaticus-infected plant for an acquisition access period of 24 h. When adults fed on Ca. L. asiaticus-infected plant, the concentration of the bacterium did not increase significantly and the pathogen was not transmitted to any citrus seedlings. In contrast, when psyllids fed on infected plant as nymphs, the concentration of the pathogen significantly increased by 25-, 360- and 130-fold from the initial acquisition day to 10, 15 and 20 days, respectively. Additionally, the pathogen was successfully transmitted to 67% of citrus seedlings by emerging adults. Our data suggested that multiplication of the bacterium into the psyllids is essential for an efficient transmission and show that it is difficult for adults to transmit the pathogen unless they acquire it as nymphs. [source] | ||||||||||