有线和无线宽带接入产品技术

射频存储系统的目标市场有两个，一个是宽带网络，一个是无线局域网：下图介绍的是第一公里的无线宽带接入系统。图的中央有一个中枢（hub)，它的周围是一个分布网络。这是一个包括光和电的、数据和模拟结合的网络，这种系统在中国的大城市都有广泛的部署。圆圈是飞利浦开发的一些结点、中枢和分布网络，包括放大器和光电设备。     

Online Calculation and Prediction of the Strip Temperature in a Hot Strip Finishing Mill

The paper deals with a physical model for the calculation of the strip temperature in a hot rolling mill. Beside the heat transfer from the strip to the environment in the different mill sections a sub‐model for the material properties of steel including phase transitions is introduced. For the application in a process automation system an online adaptation of the model to the current state of the mill is indispensable. The adaptation is explained in detail.     

Thermische Anmerkungen zu Zeitkonstanten von Wänden

Zusammenfassung Man erh?lt kompakte Approximationen von Laplace-übergangsfunktionen, wenn die Koeffizienten des Nenners aus den Zeitkonstanten des Systems abgeleitet werden. (üblicherweise führt dies auf das Problem der Nullstellensuche einer transzendenten Funktion.) Es ist bekannt (Gough [1], Stephenson [2]), da? für die meisten W?nde drei Zeitkonstanten ausreichen, um hinreichend genaue übergansfunktionen zu erhalten. Die Taylor-Entwicklung der Kettenmatrix im Laplaceraum wird für beliebige W?nde mit eindimensionalem W?rmestrom mit der Picard'schen Methode berechnet. Für ebene Mehrschichtw?nde ist dafür eine explizite L?sung angegeben. Die ersten N Zeitkonstanten werden n?herungsweise aus der (N+1). Ordnung der Partial-Summe der Taylor-Entwicklung berechnet. Dies wird mit einer generalisierten Pade-Approximation bewerkstelligt, die eine Totzeit enth?lt und direkt auf ein Nennerpolynom führt (ohne transzendente Wurzeln). Die Wurzeln konvergieren geometrisch zu den Eigenwerten mit wachsendem N (die Eigenwerte stellen die reziproken Zeitkonstanten dar). Die Komplexit?t der gesamten Prozedur liegt kaum über derjenigen für ein System mit konzentrierten Parametern der Ordnung N+1. Es werden Beispiele angegeben, um mit den „exakten” Frequenzg?ngen zu vergleichen.     

PKI: it's not dead, just resting

Like other flexible objects, the public key infrastructure sacrifices some utility in trying to be all things to all people. Mainly, PKI's generic, all-purpose identity certificates fall short of what the marketplace demands, forcing vendors to develop more economically efficient, useful, and imaginative business models. Thus, we must adapt the PKI design to the real world rather than trying to constrain the real world to match the PKI. A variety of alternative approaches, ranging from simple workarounds to designing the application to sidestep PKI's shortcomings entirely, can help solve the problems inherent in the standard X.509 model.

Despite an original design that failed to address the marketplace's needs, the use of innovative public key infrastructure models can make the technology meet today's requirements.     

AgNO<Subscript>3</Subscript> spray tests: advantages,weaknesses, and various applications to quantify chloride ingress into concrete. Part 1: Non-steady-state diffusion tests and exposure to natural conditions

Within the framework of the evaluation and the prediction of chloride-induced corrosion risks, simple and rapid AgNO₃ spray tests can be proposed for various issues. This paper forms the first part of a series. In this first part, the Maultzsch procedure (spraying of 0.1-N AgNO₃ solution + K₂CrO₄) as well as the procedure based on the use of a sole AgNO₃ solution have been investigated on a broad range of concretes. These procedures have also been compared to the Collepardi procedure (spraying of 0.1-N AgNO₃ + fluoresceine). The feasibility of these colorimetric techniques on saturated specimens cast in laboratory, after non-steady-state diffusion tests carried out in various conditions, is discussed. In addition, the results obtained from applying such spray tests in field conditions on cores drilled out from various RC test specimens exposed to a marine environment (tidal zone) and to a road and cold environment (freezing-thawing cycles and spraying of deicing salts) are presented. Colorimetric methods have in particular been applied here to the assessment of the average chloride penetration depth and of its evolution versus time (kinetics). Moreover, the detection threshold of these techniques has been investigated in various environments. The possible sources of discrepancy on the results have been analysed.     

XML-Schema

XML hat sich als Sprache zur Definition von Dokumenten für den universellen Datenaustausch etabliert. XML-Schema erm?glicht ausgefeilte Definitionen für XML-Dokumente und hat beste Chancen, die bisher eingesetzte DTD abzul?sen. Neben einer allgemeinen Einführung geht dieser Beitrag auch auf verfügbare Produkte und neue M?glichkeiten der objektorientierten Softwareentwicklung mit XML-Schema ein. Vorschl?ge an Prof. Dr. Frank Puppe <puppe@informatik.uni-wuerzburg.de> oder Dieter Steinbauer <dieter.steinbauer@schufa.de> Alle „Aktuellen Schlagw?rter” seit 1988 finden Sie unter: www.ai-wuerzburg.de/as     

Ground state systematics and collective dipole excitations of spheroidally deformed sodium clusters in a diffuse jellium model

We solve the Kohn-Sham equations self-consistently in the local density approximation for spheroidal sodium clusters in the particle range 8 ≤ Z ≤ 40. We use a smooth fermi-like jellium density to simulate the influence of the ions in the surface region and obtain similar results as Ekardt and Penzar, but slightly different regions of prolate-to-oblate transitions. We present the systematics of potential energy curves with respect to transitions between oblate, prolate and spherical shapes. Shape transitions occur at particle numbers 12/14 (prolate/oblate), 18/20/22 (oblate/spherical/prolate) and 30/32 (prolate/oblate), which are in good agreement with experimental results. The quadrupole and hexadecupole overlap of the electron density with the jellium is investigated, showing a strong hexadecupole dependence for selected clusters. Collective dipole resonances are described in a simple sum rule approach, which reveals a double splitting according to the different resonance frequencies along the principal axes of the spheroid. The systematics of the resonance peaks for the larger clusters with Z ≥ 20 is in good agreement with experimental results.