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Network Function (network + function)
Selected AbstractsPassive rational fitting of a network transfer function from its real partINTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 3 2008Anne Y. Woo Abstract A methodology is presented for the rational function approximation of a passive network function from sampled values of its real part over the bandwidth of interest. The accuracy and validity of the proposed methodology are demonstrated through its application to the fitting of several broadband, multiport transfer functions. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2008. [source] Mechanistic understanding of the fermentative L -glutamic acid overproduction by Corynebacterium glutamicum through combined metabolic flux profiling and transmembrane transport characteristicsJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 12 2004Theodora Tryfona Abstract Since the 1950s when Micrococcus glutamicus later renamed Corynebacterium glutamicum was discovered, the production of amino acids by fermentative methods has become an important aspect of industrial microbiology. Numerous studies to understand and improve the metabolic conditions leading to amino acid overproduction have been carried out. Most amino acids are currently produced by use of mutants that contain combinations of auxotrophic and regulatory mutations. L -Glutamic acid is the amino acid produced in the greatest quantities (106 tonnes per year) and Corynebacteria are central to its industrial production. However, further improvements to strain performance are difficult to obtain by empirical optimization and a more rational approach is required. The use of metabolic flux analysis provides valuable information regarding bottlenecks in the formation of desired metabolites. Such techniques have found application in elucidating flux control, provided insight into metabolic network function and developed methods to amplify or redirect fluxes in engineered bioprocesses. Hence, branch points in biosynthesis, precursor supply in fuelling reactions and export of metabolites can be manipulated, resulting in high glutamic acid overproduction by Corynebacterium glutamicum fermentations. In this review, in addition to reviewing the state of play in metabolic flux analysis for glutamate overproduction, the metabolic pathways involved in the production of L -glutamic acid, the mechanisms mediating its efflux and secretion as well as their manipulation to achieve higher glutamate production, are discussed. The link between metabolic flux and transmembrane transport of glutamic acid are also considered. Copyright © 2004 Society of Chemical Industry [source] Working memory in posttraumatic stress disorder,an event-related potential studyJOURNAL OF TRAUMATIC STRESS, Issue 2 2001Cherrie Galletly Abstract This study examined ERP topography during the updating and the utilization of working memory in subjects with PTSD. Event-related potentials of 18 participants with PTSD and 18 controls were recorded from 32 scalp electrodes during an auditory target detection task requiring the constant updating of target identity. Midline N2 and P3 abnormalities previously noted in PTSD during target detection were replicated. Scalp topographic data revealed sustained reduction in activity over the right hemisphere during working memory updating. Executive processes were associated with brief but widespread right hemisphere reductions during the P3, followed by sustained, bilateral reduction frontally. This study identifies an abnormal pattern of cortical network function during both the updating and use of working memory in PTSD. [source] Cerebrospinal fluid of brain trauma patients inhibits in vitro neuronal network function via NMDA receptors,ANNALS OF NEUROLOGY, Issue 4 2009Frauke Otto MD Neurological diseases frequently induce pathological changes of cerebrospinal fluid (CSF) that might secondarily influence brain activity, as the CSF,brain barrier is partially permeable. However, functional effects of CSF on neuronal network activity have not been specified to date. Here, we report that CSF specimens from patients with reduced Glasgow Coma Scale values caused by severe traumatic brain injury suppress synchronous activity of in vitro-generated neuronal networks in comparison with controls. We present evidence that underlying mechanisms include increased N -methyl- D- aspartate receptor activity mediated by a CSF fraction containing elevated amino acid concentrations. These proof-of-principle data suggest that determining effects of CSF specimens on neuronal network activity might be of diagnostic value. Ann Neurol 2009;66:546,555 [source] UniFAFF: a unified framework for implementing autonomic fault management and failure detection for self-managing networksINTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 4 2009Ranganai Chaparadza Today's network management, as known within the Fault, Configuration, Accounting, Performance, Security (FCAPS) management framework, is moving towards the definition and implementation of ,self-managing' network functions, with the aim of eliminating or drastically reducing human intervention in some of the complex aspects or daunting tasks of network management. The fault management plane of the FCAPS framework deals with the following functions: fault detection, fault diagnosis, localization or isolation, and fault removal. Task automation is at the very heart of self-managing (autonomic) nodes and networks, meaning that all functions and processes related to fault management must be automated as much as possible within the functionalities of self-managing (autonomic) nodes and networks, in order for us to talk about autonomic fault management. At this point in time there are projects calling for implementing new network architectures that are flexible to support on-demand functional composition for context- or situation-aware networking. A number of such projects have started, under the umbrella of the so-called clean-slate network designs. Therefore, this calls for open frameworks for implementing self-managing (autonomic) functions across each of the traditional FCAPS management planes. This paper presents a unified framework for implementing autonomic fault management and failure detection for self-managing networks, a framework we are calling UniFAFF. Copyright © 2008 John Wiley & Sons, Ltd. [source] Session initiation protocol services architectureBELL LABS TECHNICAL JOURNAL, Issue 1 2002Janet R. Dianda The session initiation protocol (SIP) is a unifying protocol for providing integrated telephony and Internet types of services, such as Web, presence, instant messaging, and chat. To provide for the integration of these disparate types of services, considerations must be given from a network point of view. However, little attention has been given in the literature to identify the network elements required to provide these services or the mechanisms for integrating these different types of services for end users. This paper describes a network-level services architecture for SIP, including network functions and entities needed to support the services integration. We will discuss how services can be incorporated at different levels in the network, and the types of services typically created at each of these levels. We will also describe a service access and mediation function, which blends disparate types of services in creating a seamless and rewarding user experience. © 2002 Lucent Technologies Inc. [source] | ||||||||||