Complex Multi Research Articles

ATM-based multimedia communication via NGSO-satellites

Future broadband satellite networks for multimedia will be seamlessly integrated into terrestrial broadband networks which often use asynchronous transfer mode (ATM) and recently also the less complex multi protocol label switching (MPLS) technique as transmission and switching protocol. In light of this, future broadband satellite networks may adopt the ATM transmission scheme and implement ATM or ATM-like switches on board the satellites. However, as compared to communication in fixed networks, satellite communication is characterized by special constraints (e.g. signal delay, channel quality, dynamic network topology) that require novel ATM-based communication technology for satellite systems. This paper presents results from the ATM-Sat project that aims to complete this technically challenging and important R&D task in the cooperation between DLR, Fraunhofer Gesellschaft and Tesat-Spacecom. In brief the following aspects have been addressed in the ATM-Sat project: development of the concept and communication technology for a multimedia satellite system with, non-geostationary orbit (NGSO) satellites; inter satellite links (ISLs); on-board ATM switching; fixed and mobile terminals; verification of the developed communication technology with a demonstrator. In particular the ATM-Sat R&D tasks cover the system and protocol architecture, on-board processing, ISL routing, up/downlink and on board ATM resource management (including medium access control), error control, IP over satellite-ATM, and active intelligent antennas. Copyright © 2005 John Wiley & Sons, Ltd.

Monitoring System for Multiphase Hydrogenation in Chemical Plants

An on-line monitoring system (MoSys) based on dimensionless mass and energy balances with adaptive functions was developed to support the operational personnel during the optimal and environmentally compatible process control of the complex multi phase hydrogenation in stirred tank reactors. For industrial testing. MoSys was integrated in a batch-information-management system (BIMS) which was also developed and implemented in the process control system (PSC) of a multipurpose reactor installation. As a result, the outputs of MoSys, such as the progress of hydrogenation, the predictive end of reaction and concentration profiles, can simultaneously be visualised with imponant process signals on terminals of PCS. The efficiency of BIMS/MoSys could be proven during two industrial hydrogenation campaigns.

Dual-regulated gene expression in mammalian cells, a novel approach to gene therapy

A variety of heterologous mammalian gene regulation systems are currently available for use in human gene therapy and tissue engineering. While individual gene regulation concepts vary significantly in key characteristics (regulation profiles, basal expression levels, human compatibility, immunogenicity, pharmacokinetics and bioavailability of the inducing agent), most of them are sufficiently elaborated to be considered for preclinical research and clinical gene therapy trials. As forefront basic research describes the cell-cycle, differentiation and apoptosis regulatory networks in mammalian cells as an increasingly complex highly interconnected globular regulon, it becomes apparent that many human diseases may originate from the slightest expression imbalances of key regulatory genes. We believe that successful gene therapy of such diseases will involve complex multi-(level) regulated multigene interventions based on a combination of several human-compatible heterologous gene regulation systems which enable optimal integration of therapeutic interventions into the cellular regulon as well as well-balanced expression of several therapeutic transgenes. Although such multiregulated multigene expression scenarios are still a vision, the following are already a scientific reality with cultured cells: (i) combination of two human compatible gene regulation systems to enable dual-regulated expression technology for independent adjustment of two different gene activities, (ii) regulatory cascades for muli-level regulated multigene interventions, and (iii) dual-autoregulated expression configurations for one-step installation of multi-level or reciprocal regulation of heterologous gene expression. This review summarizes pioneering efforts to establish dual-regulated expression technology, a strategy to combine more than one heterologous gene regulation system, to achieve difficult-to-attain cell phenotypes relevant for gene therapy, tissue engineering and basic research.

A numerical model prediction for boiling multi channel flow rate distribution and application in 600MW supercritical variable-pressure once-through boiler with vertical tube coils

Flow rate distribution is important in a multi channel system when the flow is heated non-uniformly. This paper describes a steady state approach for obtaining the flow distribution among various tubes of complex multi channel system. Based on the present approach, a program has been developed, which is directly applied in thermal hydraulic design and investigation of 600MW supercritical variable-pressure once through boiler.

Frozen-In Devil's Staircase in U(Ru1-xRhx)2Si2Mixed Compound System as Studied by Neutron Diffraction

We have carried out neutron diffraction experiments in order to study on the intermediate phase of the mixed system, U(Ru 1- x Rh x ) 2 Si 2 , of URu 2 Si 2 and URh 2 Si 2 , which are a heavy Fermion and a localized f-electron compounds, respectively. In the intermediate phase, the magnetic moment of the uranium atom has a normal magnitude but the ground state has a complex multi- Q -domain structure. The origin of this state is discussed on the basis of competing anisotropic interactions and randomness in them. An energy-based consideration is given to understand the variation of the magnetic structures in U(Ru 1- x Rh x ) 2 Si 2 and Ce(Ru 1- x Rh x ) 2 Si 2 sytems.

Bayesian Analysis of Linear and Non-Linear Population Models by Using the Gibbs Sampler

Abstract : A fully Bayesian analysis of linear and nonlinear population models has previously been unavailable, as a consequence of the seeming impossibility of performing the necessary numerical Integrations in the complex multi- parameter structures typically arising in such models. It is demonstrated that, for a variety of linear and nonlinear population models, a fully Bayesian analysis can be implemented in a straightforward manner using the Gibbs sampler. The approach is illustrated with examples involving challenging problems of outliers and mean-variance relationships in population modelling.

Energy density function determination in very-high-resolution electron-beam lithography

A proximity effect correction algorithm requires an accurate knowledge of the energy density function (EDF) deposited in the electron resist layer. In case of high-resolution electron-beam lithography (EBL), whenever the required resolution is below 0.5 μm, forward and large-angle backward scattering contribution has to be carefully analyzed. In this paper, we compare Monte Carlo (MC) simulation data with experimental point exposure measurements over different substrates and with different beam energy (range 20–40 kV). The substrates we analyze are silicon and silicon nitride membranes (2 μm thick), indium phosphide, and gold. A good correlation between MC data and experiments is proved. Experiments and MC data suggest that the usual double Gaussian fit applied to the distribution is not suitable for the application of high-resolution lithography or with high-Z materials. These data indicate that the recently proposed triple Gaussian fit can be considered as a particular case of a more complex multi Gaussian function. Experimental high-resolution resist profiles are then simulated successfully using MC EDFs in a cell development model.