Broadband multimedia applications using ATM networks:high-performance computing, high-capacity storage, and high-speedcommunication

The authors discuss the classification of a large variety of multimedia communication applications (with the emphasis on broadband and hypermedia applications), the requirements at network levels, multimedia communications concepts with suitable platforms, and the modular standardization of multimedia teleservices and the corresponding technical systems. Appropriate technologies for meeting multimedia requirements comprise public and private networks, servers for information storage and processing, intelligent user and system agents, and multimedia terminals, e.g., workstations. The authors deal with the question of service-specific or service-integrated networks, the architecture, components, and functions of asynchronous transfer model (ATM) switching systems for broadband ISDN and ATM-based signaling, and management for controlling connectivity and interactivity. Network evolution, pilot applications, and coordinated standardization are briefly considered     

Kein Problem mehr mit vergessenen Passwörtern

über die H?lfte der Studenten vergessen j?hrlich ihre Passw?rter und verursachen deshalb enorme Verwaltungsprobleme. Die Universit?t Regensburg hat einen neuen Weg beschritten, um dem Herr zu werden. Sie setzt auf die sensorlose Biometrie Tippverhalten.     

Structural background of cyclodextrin-protein interactions

Cyclodextrins are cyclic oligosaccharides with the shape ofa hollow truncated cone. Their exterior is hydrophilic and theircavity is hydrophobic, which gives cyclodextrins the abilityto accommodate hydrophobic molecules/moieties in the cavity.This special molecular arrangement accounts for the varietyof beneficial effects cyclodextrins have on proteins, whichis widely used in pharmacological applications. We have studiedthe interaction between ß-cyclodextrin and four non-carbohydrate-bindingmodel proteins: ubiquitin, chymotrypsin inhibitor 2 (CI2), S6and insulin SerB9Asp by NMR spectroscopy at varying structuraldetail. We demonstrate that the interaction of ß-cyclodextrinand our model proteins takes place at specific sites on theprotein surface, and that solvent accessibility of those sitesis a necessary but not compelling condition for the occurrenceof an interaction. If this behaviour can be generalized, itmight explain the wide range of different effects of cyclodextrinson different proteins: aggregation suppression (if residuesresponsible for aggregation are highly solvent accessible),protection against degradation (if point of attack of a proteaseis sterically ‘masked’ by cyclodextrin), alterationof function (if residues involved in function are ‘masked’by cyclodextrin). The exact effect of cyclodextrins on a givenprotein will always be related to the particular structure ofthis protein. Received May 30, 2003; revised October 27, 2003; accepted October 30, 2003     

Computational materials design: A perspective for atomistic approaches

Summary Present theoretical and computational approaches, combined with the impressive advances in computer hardware and software, open the possibility for materials design from first principles. This article presents a perspective on the relevant developments in computational chemistry, solid state physics and statistical mechanics and it assesses the merits and limitations of Hartree-Fock, density functional, semiempirical and force field approaches in terms of six criteria: capability, generality, accuracy, accessible system size, accessible time scales and computational efficiency. Functional materials for microelectronic, optical and magnetic applications currently present better opportunities for first-principles approaches than structural materials, where atomistic approaches, despite some encouraging results, are still far from capturing the full complexity of the dynamics involved in mechanical, thermal, diffusive and corrosive behavior.     

Consistency of a pair of generalized Sylvester equations

A necessary and sufficient condition is given for the existence of a simultaneous solution of a pair of generalized Sylvester equations. An auxiliary result deals with constant solutions of Sylvester equations with polynomial matrices     

Topology-Based Interlocking of Electrical Substations

Conventional interlocking of substations is usually expressed by Boolean expressions and realized by electro-mechanical relays. Since these expressions are generated by applying verbally stated interlocking rules to a specific substation configuration, any change of the substation or of the operational philosophy affects them in such a complex way that the problem has to be tackled again in most cases from the very beginning. The proposed topology-based approach suited for microprocessors decouples knowledge-base and implementation, i.e. interlocking rules, and substation configuration. It results in interlocking rules that are independent of a single line diagram and can be applied to all known substation configurations. The rules are divided into mandatory and dependent on operational philosophy. The modularity allows for applying exactly those rules specified in the special project. Any new substation does not require new programming. The inherently fault-tolerant implementation in a 765 kV GIS is briefly described.     

Application of the two-dimensional Hermitian finite difference method to linear shear deformation theory of plates and arbitrarily curved shells

Summary Starting from the linear, partial differential equations of thin shell theory including the effect of transverse shear deformation a matrix formulation is presented in which all kinematic and dynamic variables appear as differential quotients of first order.The transformation of the local field equations into an algebraic form by appropriate two-dimensional finite-difference operators leads to an unsymmetrical banded algebraic equation system from which all variables requested are directly evaluated.The constitutive equations take into consideration a symmetrically layered cross section consisting of tangentially isotropic and transversally orthotropic material. Because of the kinematic assumptions of a first approximation shell theory the deformation of the cross section can be seized in an integral sense only.Since the basic equations are formulated in tensor notation with the procedure presented shells of arbitrary curvature may be analyzed, of which surface is given as an analytic continuously differentiable function. The algorithm pointed out shows good convergence attributes. Its efficiency is demonstrated by two examples of which analytical solutions are known.