Optical and structural properties of aluminium nitride thin-films synthesized by DC-magnetron sputtering technique at different sputtering pressures

Microsystem Technologies - Aluminium nitride thin-films (AlN) were fabricated by a DC-magnetron sputtering technique at different background pressures while maintaining the same deposition...     

Electrical and morphological characterization of platinum thin-films with various adhesion layers for high temperature applications

In this paper we report on the morphological and electrical properties of platinum (Pt) thin-films with Titanium (Ti) and, alternatively, Titanium dioxide (TiO₂) as adhesion layers for high temperature applications. All films were sputter deposited on silicon substrates and afterwards annealed in air up to 800 °C. The results show that Ti diffuses into Pt grain boundaries forming oxide precipitates (TiO_x) in the Pt grain boundaries. The resistivity of Pt/Ti thin-films increased continuously with annealing temperature up to 500 °C and decreases again continuously above 500 °C. In contrast, TiO₂ demonstrates a dense stable oxide layer after annealing. Pt/TiO₂ thin-films show a continuous decrease in the sheet resistance with increasing the annealing temperature. Accordingly, TiO₂ thin-film is the preferable adhesive layer for Pt over Ti thin-films for high temperature applications.

     

Performance management for cluster-based web services

We present an architecture and prototype implementation of a performance management system for cluster-based web services. The system supports multiple classes of web services traffic and allocates server resources dynamically so to maximize the expected value of a given cluster utility function in the face of fluctuating loads. The cluster utility is a function of the performance delivered to the various classes, and this leads to differentiated service. In this paper, we will use the average response time as the performance metric. The management system is transparent: it requires no changes in the client code, the server code, or the network interface between them. The system performs three performance management tasks: resource allocation, load balancing, and server overload protection. We use two nested levels of management. The inner level centers on queuing and scheduling of request messages. The outer level is a feedback control loop that periodically adjusts the scheduling weights and server allocations of the inner level. The feedback controller is based on an approximate first-principles model of the system, with parameters derived from continuous monitoring. We focus on SOAP-based web services. We report experimental results that show the dynamic behavior of the system.     

The generalizedD [X] /D/1 queue: A flexible computer communications model

A generalization of theD ^[X] /D/1 queue is investigated, where independent and identically distributed (i.i.d) batches of customers arrive at a single-server queue periodically. The service requirement of a customer is a fixed constant equal for all the customers. In the time between two successive arrivals, the server can accommodate exactlyK1 customers. The queue size and the waiting time distributions for the infinite buffer queue are derived. Important numerical aspects are addressed and simple approximations for light and heavy traffic for various values ofK and Poisson distributed batches are proposed. Finally, the analysis for the finite queue is highlighted and its blocking probability derived.     

DQDB+-/: a fair and waste-free media access protocol fordual bus metropolitan networks

A media access protocol that achieves a fair distribution of the bandwidth in one round-trip delay is presented. The protocol is based on a unique solution to a fair and waste-free bandwidth allocation. This bandwidth allocation can be implemented in a distributed manner. A comparison of the new protocol with the DQDB (distributed queue dual bus) protocol shows considerable advantages regarding the transmission delay of messages and the time a station needs to obtain a fair portion of the available bandwidth. The advantages of the protocol become more apparent for large networks and high transmission speeds. In addition, the new protocol can perform nonuniform bandwidth allocations     

A Novel Stochastic Model of the Photo-Thermoelasticity Theory of the Non-Local Excited Semiconductor Medium

Silicon - A novel technique under the effect of stochastic heating due to the thermal effect of the photothermal theory is investigated. Realistically, stochastic processes are taken on the...