Bracketing of failure path probability in a system with ageing repair times

In practical terms, the distributions of repair times are not known; we have only mean values. We show here that by assuming these distributions to be ageing, it is possible in many cases to bracket availability and reliability using only Mean Times to Repair. Furthermore, this computation can be carried out using Markov models.     

La nouvelle numérotation téléphonique en France

This paper describes the studies for the organization and the results of the numbering scheme change made in the French network.     

Some remarks on rare-event approximation

Two fault-tree analysis methods to compute the minimal cutsets union probability are: the rare-event approximation, and the minimal cutset upper-bound. The rare-event approximation is accurate if all the basic events have low probabilities. The accuracy improvement provided by the minimal cutset upper-bound approximation is negligible     

Multi-modal wave propagation in smart structures with shunted piezoelectric patches

The propagation of wave modes in elastic structures with shunted piezoelectric patches is dealt with in this work. The wave finite element approach, which is based on the finite element method and periodical structure theory, is firstly developed as a prediction tool for wave propagation characteristics in beam like structures, and subsequently extended to consider shunted piezoelectric elements through the diffusion matrix model (DMM). With these numerical techniques, reflection and transmission coefficients of propagating waves in structures with shunted piezoelectric patches can be calculated. The performance of shunted piezoelectric patches on the control of wave propagation is investigated numerically with the DMM. Forced response of the smart structure can also be calculated, and based on which the time response of the structure can be obtained via an inverse discrete fourier transform approach. These general formulations can be applied to all types of slender structures. All these numerical tools can facilitate design modifications and systematic investigations of geometric and electric parameters of smart structures with shunted piezoelectric elements.     

高压空载线路的可控开、合研究

借助于配有合闸电阻的断路器来限制超高压线路上的开、合过电压的传统方法已被广泛应用的实践证明是很有效的.然而,还可以展望其它的方法,特别是控制断路器瞬间合闸的的方法.研究了超高压线路上采用可控开、合的可能性,并比较了现有的几种解决办法.同时考虑了可能碰到的各种电网特性.详细说明了因断路器的性能造成电网中的过电压水平及所造成的后果.本文的重点放在应用方面的关键问题.     

On the behavior of shock waves in deformable dielectric materials

In this paper, the behavior of plane shock waves propagating in elastic dielectrics is examined. The differential equation governing the amplitude of wave and formulae concerning the polarization changes across the shock are deduced. Some particular situations are studied in detail.     

Interactive evolution for cochlear implants fitting

Cochlear implants (CI) are devices that become more and more sophisticated and adapted to the need of patients, but at the same time they become more and more difficult to parameterize. After a deaf patient has been surgically implanted, a specialised medical practitioner has to spend hours during months to precisely fit the implant to the patient. This process is a complex one implying two intertwined tasks: the practitioner has to tune the parameters of the device (optimisation) while the patient’s brain needs to adapt to the new data he receives (learning). This paper presents a study that intends to make the implant more adaptable to environment (auditive ecology) and to simplify the process of fitting. Real experiments on volunteer implanted patients are presented, that show the efficiency of interactive evolution for this purpose.