This work considers the characterization of linear PVC acoustic properties using a linear ultrasonic measurement technique and the non-collinear ultrasonic wave mixing technique for measurement of the physical ageing state in PVC. The immersion pulse-echo measurements were used to evaluate phase velocity dispersion and attenuation of longitudinal waves in PVC test specimens. The suggested nonco...

The attenuation provided by a hearing protection device (HPD) in the field is usually estimated by applying a derating factor to the laboratory-determined noise reduction rating (NRR) of the HPD. However, attenuation is highly dependent on individual-specific HPD fit. Prediction of an individual's attenuation depends on the accuracy of the measurement system and the variability of attenuation o...

In this paper, an iterative LMI approach is proposed to deal with the control problem for Networked Control Systems (NCSs) with random communication delays. Both random measurement and control delays are simultaneously considered due to limited communication capacity. The NCSs with both measurement and control delays are modelled as a stochastic parameter system which contains two independent B...

The ultrasonic attenuation coefficient of a fluid or solid material is an acoustic parameter routinely estimated in nondestructive evaluation (NDE) and biological tissue characterization. In this paper, a new measurement and analysis technique for estimating the attenuation coefficient as a function of frequency for a fluid or solid is described. This broadband technique combines two establishe...

In this paper, we consider the design of interconnected H∞ feedback control systems with quantized signals. We assume that a decentralized dynamic output feedback has been designed for an interconnected continuous-time LTI system so that the closed-loop system is stable and a desired H∞ disturbance attenuation level is achieved, and that the subsystem measurement outputs are quantized before th...

A highly accurate method for the determination of the detection efficiency of a silicon single-photon avalanche diode (Si-SPAD) is presented. This method is based on the comparison of the detected count rate of the Si-SPAD compared to the photon rate determined from a calibrated silicon diode using a modified attenuator technique, in which the total attenuation is measured in two attenuation st...

Using the South Pole Acoustic Test Setup (SPATS) and a retrievable transmitter deployed in holes drilled for the IceCube experiment, we have measured the attenuation of acoustic signals by South Pole ice at depths between 190 m and 500 m. Three data sets, using different acoustic sources, have been analyzed and give consistent results. The method with the smallest systematic uncertainties yield...

We present here the results of the measurements of rain-induced attenuation in the vertically polarized signal propagating at 12.25GHz during some rain events, which occurred in the rainy season of the year 2001 at Yongin, Korea. The attenuation measured experimentally was compared with that obtained using the International Telecommunication Union Radio Communication Sector (ITU-R) model, the S...

The dependence of vegetation attenuation on propagation geometry has been experimentally investigated at SHF band for isolated single trees. Two measurement heights (Trunk and Canopy) have been used in these experiments that involve three fully foliated trees, Common Whitebeam (Sorbus aria), Silver Maple (Acer Saccharinum) and Common Hazel (Corylus Avellana). Result shows that apart from freque...

SPECT detects γ-rays from administered radiopharmaceutical within the patient body. γ-rays pass through different tissues before reaching detectors and are attenuated. Attenuation can cause artifacts; therefore different methods are used to minimize attenuation effects. In our study efficacy of Chang method was evaluated for attenuation purpose, using a custom made heart phantom. Due to d...