An adaptive survivability admission control algorithm using backup path for high‐speed networks

In this paper, we propose an adaptive survivability admission control algorithm using a backup path for high‐speed networks. For each call request, the proposed algorithm selects a combination of working path and backup path. Two BP selection methods, min‐cost and min‐expectation, are suggested. Computational experiments indicate that the proposed algorithm significantly reduces the consumption of backup capacity while still maintaining 100% survivability upon a single link failure and near 80% survivability upon double link failures. Copyright © 2003 John Wiley & Sons, Ltd.     

Measurement Biases in the Bender Element Test

This paper reconsiders the signals that are transmitted in bender element tests and the associated transfer functions to identify the problems that bias the velocity (travel time) determination. The findings of the numerical and physical experiments show that errors appearing in the velocity estimation can be traced to (1) the near-field effect and (2) the influence caused by the transfer function of the receiver system, HR. The second factor also creates distinguishing changes between the source and receiver signals. In a two-receiver measurement system, the accurate travel time (velocity) can be identified by the cross correlation of the two receiver signals only if the near field is not pronounced and the two receivers possess very similar transfer functions. The near-field effect can be effectively avoided by placing the sensors at r1/λ ≥ 2 and r1/r2 ≥ 2, where r1 and r2=distances between the source and the first and second receivers, respectively, and λ=wavelength. In a one-receiver measurement system, the inherent time delay caused by the transfer function of the receiver system, HR, has to be quantified and corrected. The near-field effect also can be avoided by placing the receiver at least 2λ away from the source.     

Analysis of Hot-Carrier Luminescence for Infrared Single-Photon Upconversion and Readout

We propose and analyze a new method for single-photon wavelength up-conversion using optical coupling between a primary infrared (IR) single-photon avalanche diode (SPAD) and a complementary metal oxide semiconductor (CMOS) silicon SPAD, which are fused through a silicon dioxide passivation layer. A primary IR photon induces an avalanche in the IR SPAD. The photons produced by hot-carrier recombination are subsequently sensed by the silicon SPAD, thus, allowing for on-die data processing. Because the devices are fused through their passivation layers, lattice mismatch issues between the semiconductor materials are avoided. We develop a model for calculating the conversion efficiency of the device, and use realistic device parameters to estimate up to 97% upconversion efficiency and 33% system efficiency, limited by the IR detector alone. The new scheme offers a low-cost means to manufacture dense IR-SPAD arrays, while significantly reducing their afterpulsing. We show that this high-speed compact method for upconverting IR photons is feasible and efficient.     

Design and test of an electronic nose for monitoring the air quality in the international space station

Long-term manned space missions requires a continuous monitoring of the air quality inside the spacecraft. For this scope, among several different solutions, electronic noses have been considered. On behalf of European Space Agency an electronic nose specifically designed for air quality control in closed environment is under development. After several ground experiments concerning the monitoring of a biofilter efficiency, the instrument has been tested during the ENEIDE mission on board of the International Space Station. in this paper the instrument main concepts and its performance in ground and space experiments are illustrated.     

Automatic EMI Measurement and Filter Design System for Telecom Power Supplies

Tests for compliance with conducted emission limits are usually carried out during the electrical product design process. Electromagnetic interference (EMI) filters are widely used for filtering excessive conducted emissions on a power cord. In this paper, a personal computer (PC)-based automatic EMI measurement and filter design system for telecom power supplies is proposed. The common-mode (CM) and differential-mode (DM) emissions in the live or the neutral line can be measured and recorded separately. The trial-and-error guesswork in selecting the filter components can be minimized by the proposed automatic filter design system. In other words, the EMI suppression effort is greatly reduced by the fast PC computing speed and the man-machine interface. The developed system can be an effective noise diagnosis and filter design tool for EMI engineers.     

Assessment of MW-mile method for pricing transmission services: a negative flow-sharing approach

A negative flow-sharing approach to allocate transmission transaction charges among users of transmission services is proposed. The approach uses the properties of the MW-mile method but takes into account the economic benefits of both trading parties by analysing their shares in negative power flow or counterflow. This approach is incorporated with the justified distribution factor for power flow tracing purposes. Two case studies based on a 5-bus system and an IEEE 14-bus system are used to illustrate the proposed approach. The results show that the proposed approach has merit over the traditional MW-mile approaches in the context of revenue reconciliation of transmission services, regardless of transaction arrangements and locations. The profit-sharing concept introduced here provides a better economic signal in allocating charges for counterflows, which could benefit trading parties.     

The design and implementation of seeded trees: an efficient methodfor spatial joins

Existing methods for spatial joins require pre-existing spatial indices or other precomputation, but such approaches are inefficient and limited in generality. Operand data sets of spatial joins may not all have precomputed indices, particularly when they are dynamically generated by other selection or join operations. Also, existing spatial indices are mostly designed for spatial selections, and are not always efficient for joins. This paper explores the design and implementation of seeded trees, which are effective for spatial joins and efficient to construct at join time. Seeded trees are R-tree-like structures, but divided into seed levels and grown levels. This structure facilitates using information regarding the join to accelerate the join process, and allows efficient buffer management. In addition to the basic structure and behavior of seeded trees we present techniques for efficient seeded tree construction, a new buffer management strategy to lower I/O costs, and theoretical analysis for choosing algorithmic parameters. We also present methods for reducing space requirements and improving the stability of seeded tree performance with no additional I/O costs. Our performance studies show that the seeded tree method outperforms other tree-based methods by far both in terms of the number disk pages accessed and weighted I/O costs. Further, its performance gain is stable across different input data, and its incurred CPU penalties are also lower     

Acid neutralisation capacity and hydration behaviour of incineration bottom ash-Portland cement mixtures

The present paper deals with the use of incineration bottom ash in cementitious systems. The results of the physical-mechanical characterisation of the solidified products were discussed elsewhere, while the present work focuses on the acid neutralisation capacity (ANC) of the investigated mixtures as a means to evaluate the type of hydration products and their relative amounts in the solid matrix. The approach consists of differential acid neutralisation analysis, which was validated using traditional X-ray diffraction (XRD) methods.     

Impacts of gate structure on dynamic threshold SOI nMOSFETs

The effects of different substrate-contact structures (T-gate and H-gate) dynamic threshold voltage silicon-on-insulator (SOI) nMOSFETs (DTMOS) have been investigated. It is found that H-gate structure devices have higher driving current than T-gate under DTMOS-mode operation. This is because H-gate SOI devices have larger body effect factor (/spl gamma/), inducing a lager reduction of threshold voltage. Besides, it is found that drain-induced-barrier-lowering (DIBL) is dramatically reduced for both T-gate and H-gate structure devices when devices are operated under DTMOS-mode.