Distributed microtrigeneration systems

In recent years, great attention, both in research and application fields, has been focused on the transition from centralized to decentralized (or Distributed Generation, DG) energy “production” systems. This process is currently being carried out partially. The benefits and drawbacks that DG will provide to the end-user and to the community have also been analyzed in both technical and scientific literature. All over the world researchers are strongly involved in the so-called “hydrogen economy” scenario that expects a geographically widespread system of production, storage, transportation and use of hydrogen.     

A frame-level measurement apparatus for performance testing of ATM equipment

Performance testing of asynchronous transfer mode (ATM) equipment is dealt with here. The attention is principally paid to frame-level metrics, recently proposed by the ATM Forum because of their suitability to reflect user-perceived performance better than traditional cell-level metrics. Following the suggestions of the ATM Forum, more and more network engineers and production managers are interested today in these metrics, thus increasing the need of instruments and measurement solutions appropriate to their estimation. Trying to satisfy this exigency, a new VME extension for instrumentation (VXI) based measurement apparatus is proposed in the paper. The apparatus features a suitable software, developed by the authors, which allows the evaluation of the aforementioned metrics by simply making use of common ATM analyzers; only two VXI line interfaces, capable of managing the physical and ATM layers, are, in fact, adopted. Some details concerning ATM technology and its hierarchical structure, as well as the main differences between frames, specific to the ATM adaptation layer, and cells, characterizing the underlying ATM layer, are first given. Both the hardware and software solutions of the measurement apparatus are then described in detail, paying particular attention to the measurement procedures implemented. In the end, the performance of a new ATM device is assessed through the proposed apparatus.     

Measuring $I/Q$ Impairments in WiMAX Transmitters

This paper presents a new method for measuring the I /Q impairments affecting the worldwide interoperability for microwave access (WiMax) transmitters through the analysis of the signal acquired through a general-purpose I /Q receiver. Based on a model of the effects of the I /Q impairments on the output signal that is suitable for orthogonal frequency-division multiplexing (OFDM) systems like WiMax, the method is designed to correctly take into account the peculiarities of systems compliant with the IEEE 802.16-2004 standard, such as the potentially noxious effects of the impairments on signal normalization and threshold decisions. The results of the experiments carried out on the standard-compliant signals are given.     

A new measurement method for through-the-wall detection and tracking of moving targets

The paper deals with a new measurement method for through-the-wall detection and tracking of hidden targets (e.g. human bodies in rescue missions) in two-dimensional scenes, by using radiofrequency signals. In particular, the method is based on a multisensor system and exploits an advanced imaging technique, which takes advantages from a regularized linear inversion scheme.     

Thin thickness measurements by means of a wavelet transform-based method

A non-invasive method for thin thickness measurements of multilayer structures is presented herein. This measurement method uses the wavelet transform for the analysis and processing of the ultrasonic signal received from the structure under test. The wavelet transform also shows itself to be a powerful tool for the detection of partially overlapping echoes in a noisy environment. This paper first describes the basic idea underlying the measurement method and then a procedure, set up by the authors, and suitable for the validation of the method when a standard multilayer structure to be used as a reference is not available, is presented and discussed. Finally, measurements of the thicknesses of actual multilayer structures and, in particular, of structures in the ophthalmic and microelectronic technology field, are carried out.     

Advanced processing techniques of high-voltage impulse test signals

Automated analysis and processing of the digital records obtained in high-voltage (HV) impulse tests requires special techniques that are able to detect and characterize all sorts of disturbances (of short and long duration) in all waveform types (full, chopped, and sliced). Especially for the cases where a short-duration disturbance has to be removed before the evaluation of the impulse parameters, it is important to characterize the disturbance both in time and frequency. This paper describes a new technique based on the wavelet transform used for this purpose. Experimental results show the technique's reliability when applied to actual HV impulses     

Cross-Layer Measurements for a Comprehensive Characterization of Wireless Networks in the Presence of Interference

Assessing the overall performance of wireless communication networks is of key importance for optimal management and planning. With special regard to wireless networks operating in an unlicensed band, evaluating overall performance mainly implies facing the coexistence issues, which are associated with the contemporaneous presence of true and interfering signals at the physical layer. This task is difficult to fulfill only on the basis of single-layer measurements, if not prohibitive; a partial perspective of network behavior would, in fact, be gained. With this concern, a cross-layer approach is presented hereinafter. It provides for several measurements to be concurrently carried out at different layers through a proper automatic station. It aims to correlate the values of the major physical-layer quantities (e.g., channel power and signal-to-interference ratio) exhibited by those characterizing the key higher layers' parameters (e.g., packet-loss ratio and one-way delay) in the presence of interference. A first step toward a full characterization of how the effects of a problem, which is experienced at the physical layer, propagates along the whole protocol stack, can thus be taken.     

New digital signal-Processing approach for transmitter measurements in third generation Telecommunications systems

The rapid growth of third generation (3G) telecommunications systems has created the need for getting new test equipment as well as getting measurement techniques up and running in a very short time. Trying to satisfy this exigency, a new measurement method for testing 3G transmitters is proposed here. Thanks to the use of time-frequency distributions, the method provides a unified approach for carrying out, automatically and in a very straightforward manner, most measurements needed to fulfill the aforementioned task. After a brief outline of 3G technology basics, some details concerning transmitter tests are given. The fundamental steps of the proposed method are then described with references to a clarifying example, also highlighting advantages with respect to other measurement solutions. At the end, the performance of the method is assessed by means of several experiments on both simulated and emulated signals.