Experimental Assessment of the Backoff Behavior of Commercial IEEE 802.11b Network Cards

It has been observed that different IEEE 802.11 commercial cards produced by different vendors experience different performance, either when accessing alone the channel, as well as when competing against each other. These differences persist also when thorough measurement methodologies (such as RF shielding, laptop rotation, etc) are applied, and alignment of the environmental factors (same laptop models, traffic generators, etc) is carried out. This paper provides an extensive experimental characterization of the backoff operation of six commercial NIC cards. It suggests a relevant methodological approach, namely a repeatable, well defined, set of experiments, for such a characterization. …

A novel technique for the CMRR improvement in a portable ECG system

This paper presents a new technique to improve the quality of the ECG signals, increasing the Common Mode Rejection Ratio (CMRR). We developed a portable wireless Bluetooth ECG system able to acquire 12 leads, communicating with Smartphones and PCs. Many experiments have been made for measuring CMRR decay due to the difference on skin-electrodes impedances, the asymmetries of the amplifiers input stages and external components. Using some digital potentiometers, the system is able to compensate for these, increasing the CMRR of about 18 dB.

PPG embedded system for blood pressure monitoring

In this work, we have designed and implemented a microcontroller-based embedded system for blood pressure monitoring through a PhotoPlethysmoGraphic (PPG) technique. In our system, it is possible to perform PPG measurements via reflectance mode. Hardware novelty of our system consists in the adoption of Silicon PhotoMultiplier detectors. The signal received from the photodetector is used to calculate the instantaneous heart rate and therefore the heart rate variability. The obtained results show that, by using our system, it is possible to easily extract both the PPG and the breath signal. These signals can be used to monitor the patients during the convalescence both in hospital and at hom…

Sale operatorie. Studio dei fenomeni di inquinamento fisico, chimico e microbiologico

Vengono descritte le attività di ricerca teoriche e sperimentali inerenti allo studio dei fenomeni di inquinamento fisico, chimico e microbiologico nelle sale operatorie ai problemi di ipotermia del paziente ad al comfort termoigrometrico per il personale

Artificial dielectric optical structures: A challenge for nanofabrication

Diffractive optical components can be made using multiple level kinoforms or single level artificial dielectric structures. The latter require the fabrication of pillars of equal depth but differing width and spacing. As a demonstration device, the diffractive optic equivalent of a wedge has been made in GaAs for use at 1.15 μm. The need for all pillars to have the same height was met by using a selective etch and a very thin etch-stop layer on AlGaAs. The experimental diffraction efficiency was 87.8%, among the best ever obtained and close to the theoretical maximum of 97.6%. © 1998 American Vacuum Society.

FLUMO: FLexible Underwater MOdem

The last years have seen a growing interest in underwater acoustic communications because of its applications in marine research, oceanography, marine commercial operations, the offshore oil industry and defense. High-speed communication in the underwater acoustic channel has been challenging because of limited bandwidth, extended multipath, refractive properties of the medium, severe fading, rapid time variation and large Doppler shifts. In this paper, we show an implementation of a flexible Software-Defined Acoustic (SDA) underwater modem, where modulation parameters are completely tunable to optimize performance. In particular, we develop the system architecture following two key ideas. …

Impact of the erase algorithms on flash memory lifetime

This paper presents a comparative study on the impact of the erase algorithm on flash memory lifetime, to demonstrate how the reduction of overall stress, suffered by memories, will increase their lifetime, thanks to a smart management of erase operations. To this purpose a fixed erase voltage, equal to the maximum value and the maximum time-window, was taken as the reference test; while an algorithm with adaptive voltage levels and the same overall time-window was designed and implemented in order to compare their experimental results. This study was carried out by using an innovative Automated Test Equipment, named Portable-ATE, tailored for Memory Test Chip and designed for performance e…

Fabrication of Diffractive Optics: Surface Reliefs and Artificial Dielectrics

After a period of fundamental theoretical research, the field of diffractive optics is now reaching a time of assessment, when we can define the useful limits of each design procedure. Selecting a suitable procedure derives from a compromise between several factors, including design time, desired optical efficiency, and precision. A major consideration in finding such a compromise has been, and still is today, the availability of technologies which can realize the design by generating the diffracting structure with assigned tolerances.

Reduced weather data for building climatization and application to 29 European locations

Abstract A method for setting up a reference year of reduced temperature data, proposed by Klein and Erbs, has been applied by us to 29 European locations for which an official test-reference year is available. This reference year of reduced temperatures may be utilized in computer programs for analysis of the thermal behaviour of buildings. The effectiveness of the method has been tested by calculating the annual energy demand in 29 European locations for three modules with different thermophysical characteristics.

Proof of Concept of an Irradiance Estimation System for Reconfigurable Photovoltaic Arrays

In order to reduce the mismatch effect caused by non-uniform shadows in PV arrays, reconfigurable interconnections approaches have been recently proposed in the literature. These systems usually require the knowledge of the solar radiation affecting every solar module. The aim of this work is to evaluate the effectiveness of three irradiance estimation approaches in order to define which can be well suited for reconfigurable PV arrays. It is presented a real-time solar irradiance estimation device (IrradEst), implementing the three different estimation methods. The proposed system is based on mathematical models of PV modules enabling to estimate irradiation values by sensing a combination …

A clear sky atmospheric model valid for the mediterranean zone

Abstract The ASHRAE clear sky model in the version proposed by G.L. Powell has been applied to a set of clear days from two coastal locations of Yugoslavia. The results have provided further elements to confirm the existence of a clear sky atmospheric model valid for the whole Mediterranean zone. This model is characterized by values of the atmospheric extinction coefficient higher than the corresponding ASHRAE ones with upper limits defined by the regression curve derived by using data of Palermo.

Ventilation systems and thermal conditions in operating rooms

A survey on the microclimate in Palermo city using the public transport system

This work presentes the results of an extensive survey on the microclimate in Palermo city using the public transport system

An embedded datalogger with a fast acquisition rate for in-vehicle testing and monitoring

A very compact and high performance datalogger for automotive in-vehicle testing is here described. The small logger dimensions and the availability of a CAN interface allows to easily implement multiple and distributed acquisition schemes, very challenging with traditional instrumentation. High acquisition rate, up to 100 Ksps/ch, and low cost was obtained through a very accurate hardware and software design.

Wide bandwidth impedance meter using low rate random sampling

A novel impedance measurement method based on random sampling of voltage and current signals is proposed. This technique dramatically reduces the sampling frequency requirements, thus circumventing the limitations imposed by maximum speed of the analog to digital converter and the signal processing unit. The lowering of the sampling frequencies allows the design and the implementation of an almost all digital architecture by using a simple microprocessor based embedded system and a digital frequency synthesizer. The basic principles are presented, and the implemented algorithms are described. Experimental results show the instrument performances compared to others commercial alternatives.

Air quality and relative humidity in commercial aircrafts: an experimental investigation on short-haul domestic flights

Abstract Nowadays the achievement of a comfortable environment in aircraft cabins is a factor of paramount importance in air travel business competition; on the other hand, the need of reducing the propulsion fuel cost has driven the airline companies to adopt air handling systems that may reduce the levels of thermal comfort and air quality inside the cabins of commercial airliners. With the aim of contributing to a better knowledge of this matter, this paper reports the results of an experimental study upon the indoor air quality aboard commercial aircrafts for 14 domestic flights less than 1 h and half long. The parameters monitored were temperature, relative humidity and carbon dioxide …

The ASHRAE clear sky model. An evaluation in the Mediterranean Zone

Abstract The ASHRAE clear sky model in the version proposed by G. L. Powell is here applied to a yearly set of data for Palermo with small scale time intervals. The model is shown to yield computed values generally higher than the measured ones. New values for the atmospheric extinction coefficient are derived and proposed for the application to the Mediterranean atmosphere. A successful verification is performed using hourly data of Genoa, a location belonging to the same meteoclimatic area.

Ventilation Problems in Heritage Buildings

The control of indoor conditions in heritage buildings, such as castles or museums, is of paramount importance for the proper preservation of the artworks kept in. As heritage buildings are often not equipped with HVAC systems, it is necessary to provide proper interventions and measures with the aim of monitoring and controlling indoor physical parameters. Moreover, another requirement should be achieved in such buildings, that is the maintenance of the safety conditions in presence of visiting people. This work reports the results of a survey carried on a hall of a historical palace, aimed to assess an useful correlation between CO2 concentration and occupancy levels.

Embedding Monitoring Systems for Cured-In-Place Pipes

This paper proposes a non-intrusive electrical measurement system for monitoring some relevant parameters in pipeline systems. Temperature and flow-rate are monitored, using MEMS sensors. The flow-rate is evaluated by measuring pipe vibration, with a 3 axis accelerometer, induced by turbulence when fluid flows within the tube. The sensors are embedded, during the curing process of the cured-in-place pipes, in the pipes wall making the system suitable to be installed in renewed or new pipeline. The first experimental results show that it may be possible to obtain, at low-cost, a fully monitored distribution network.

Resist Coating of Cylindrical Samples for 3‐D Lithography

A quantitative investigation of a dipping technique for depositing a thin layer of resist on circularly symmetrical objects is presented. The results obtained are valuable for preparing three-dimensional (3-D) surfaces suited for spatial microlithographic processes in the 1 to 10 μm linewidth range. © 1995, MCB UP Limited

Design and Performance Evaluation of a High Power-Density EMI Filter for PWM Inverter-Fed Induction-Motor Drives

This paper presents the design of an electromagnetic interference (EMI) filter for a low-voltage high-current induction-motor drives supplied by dc power grids. In order to effectively design the EMI filter, a suitable common-mode/differential-mode (CM/DM) separation technique has been used. Due to the high operating currents, the software-based separation technique using time-domain measurements has been applied. The proposed technique allows the CM and DM sections of the EMI filter to be properly selected in a more economical way, i.e., without the need of a dedicated hardware or costly radio frequency (RF) instrumentation. The design has been done according to a power-density criterion. …

Signal to Noise Ratio of Silicon Photomultipliers measured in the Continuous Wave Regime

We performed a Signal to Noise Ratio characterization, in the continuous wave regime, at different bias voltages, frequencies and temperatures, on a novel class of silicon photomultipliers fabricated in planar technology on silicon p-type substrate. Signal to Noise Ratio has been measured as the ratio of the photogenerated current, filtered and averaged by a lock-in amplifier, and the Root Mean Square deviation of the overall current flowing to the device. The measured noise takes into account the shot noise, resulting from the photocurrent and the dark current. We have also performed a comparison between our SiPMs and a photomultiplier tube in terms of Signal to Noise Ratio, as a function …

Responsivity measurements of silicon carbide Schottky photodiodes in the UV range

We report on the design and the electro-optical characterization of new classes of 4H-SiC Schottky UV detectors, fabricated employing Ni 2 Si interdigitated strips. We have measured, in dark conditions, the forward and reverse I-V characteristics as a function of temperature and C-V characteristics. Responsivity measurements of the devices, as function of wavelength in the UV range, of package temperature and of applied reverse bias are reported. We also compared devices featuring different strip pitch sizes, discussing their performances, and found the device exhibiting best results.

Experimental results of a low cost weather buoy

An FPGA-Based Software Defined Radio Platform for the 2.4GHz ISM Band

A prototype of a Software Defined Radio (SDR) platform has been successfully designed and tested implementing a reconfigurable IEEE 802.11 and ZigBee receiver. The system exploits the reconfiguration capability of an FPGA for implementing a number of receiver configurations that share the same RF front-end. Configurations can be switched at run time, or can share the available logic and radio resource.

DEMO: Unconventional WiFi-ZigBee communications without gateways

Nowadays, the overcrowding of ISM bands is becoming an evident limitation for the performance and widespread usage of 802.11 and 802.15.4 technologies. In this demo, we prove that it is possible to opportunistically exploit the inter-technology interference between 802.11 and 802.15.4 to build an unconventional low-rate communication channel and signalling protocol, devised to improve the performance of each contending technology. Differently from previous solutions, inter-technology communications do not require the deployment of a gateway with two network interfaces, but can be activated (when needed) directly between two heterogeneous nodes, e.g. a WiFi node and a ZigBee node. This capab…

Design and realization of a portable multichannel continuous wave fNIRS

A design and implementation of a portable functional Near InfraRed Spectroscopy embedded system prototype is described. In this theoretical and experimental work, we present an embedded system hosting 64 LED sources and 128 Silicon PhotoMultiplier detectors (SiPM). The elementary part of the structure is a flexible probe “leaf” consisting of 16 SiPMs, 4 couples of LEDs, each operating at two wavelengths, and a temperature sensor. The hardware system is based on an ARM main microcontroller that allows to perform both the switching time of LEDs and the acquisition of the SiPM outputs. The performed preliminary experimental tests achieved very promising results, thus demonstrating the effectiv…

Design and development of a fNIRS system prototype based on SiPM detectors

Functional Near Infrared Spectroscopy (fNIRS) uses near infrared sources and detectors to measure changes in absorption due to neurovascular dynamics in response to brain activation. The use of Silicon Photomultipliers (SiPMs) in a fNIRS system has been estimated potentially able to increase the spatial resolution. Dedicated SiPM sensors have been designed and fabricated by using an optimized process. Electrical and optical characterizations are presented. The design and implementation of a portable fNIRS embedded system, hosting up to 64 IR-LED sources and 128 SiPM sensors, has been carried out. The system has been based on a scalable architecture whose elementary leaf is a flexible board …

An analysis of direct solar transmittance and atmospheric turbidity in the Mediterranean climatic belt

Abstract The empirical model developed by King and Buckius for the direct transmission in clear sky is applied to hourly data of two Yugoslav locations exhibiting typical meteoclimatic characteristics common to the whole Mediterranean belt. The occurrence of “very clear”, “clear” and “very hazy” hours, after the usually accepted definitions, is determined and discussed. The degree of accuracy of the previsional model is investigated performing the comparison with the corresponding values obtained directly by energetic procedure. A general overestimate of the transmittance is experienced with notable deviations in meteorological conditions affected by the presence of dense clouds which behav…

Design and implementation of a portable fNIRS embedded system

We report on the design, development and operation of a portable, low cost, battery-operated, multi-channel, functional Near Infrared Spectroscopy embedded system, hosting up to 64 optical sources and 128 Silicon PhotoMultiplier optical detectors. The system is realized as a scalable architecture, whose elementary leaf consists of a probe board provided with 16 SiPMs, 4 couples of bi-color LED, and a temperature sensor, built on a flexible stand. The hardware structure is very versatile because it is possible to handle both the switching time of the LED and the acquisition of the photodetectors, via an ARM based microcontroller.

An Experimental Testbed and Methodology for Characterizing IEEE 802.11 Network Cards

It has been observed that IEEE 802.11 commercial cards produced by different vendors show a different behavior in terms of perceived throughput or access delay. Performance differences are evident both when the cards contend alone to the channel, and when heterogeneous cards contend together. Since the performance misalignment does not disappear by averaging the environmental factors (such as propagation conditions, laptop models, traffic generators, etc), it is evident that the well known throughput-fairness property of the DCF protocol is not guaranteed in actual networks. In this paper we propose a methodological approach devised to experimentally characterize the IEEE 802.11 commercial …

Design and experimental test of a low costweather buoy

The importance of prevention plans based on realistic inundation scenarios was dramatically highlighted by the Indian Ocean Tsunami of 26 December 2004. But also in the Mediterranean, sea storms basin are a quite common event especially during winter months. These scenarios are generally based on numerical models of tsunami wave propagation that can become more realistic and effective when calibrated with the distribution of true data acquired by special weather buoy. In this paper we present the result of an experimental weather buoy built by DEIM of University of Palermo, that is characterized by small cost and big versatility.

Responsivity measurements of 4H-SiC Schottky photodiodes for UV light monitoring

We report on the design and the electro-optical characterization of a novel class of 4H-SiC vertical Schottky UV detectors, based on the pinch-off surface effect and obtained employing Ni2Si interdigitated strips. We have measured, in dark conditions, the forward and reverse I–V characteristics as a function of the temperature and the C–V characteristics. Responsivity measurements of the devices, as a function of the wavelength (in the 200 – 400 nm range), of the package temperature and of the applied reverse bias are reported. We compared devices featured by different strip pitch size, and found that the 10 μm device pitch exhibits the best results, being the best compromise in terms of fu…

Misfire Detection System based on the Measure of Crankshaft Angular Velocity

Misfire detection systems are becoming increasingly important in automotive market due to recent environmental issues (Euro rules). An early misfire diagnosis also allows to prevent damages to the exhaust emission system and consequent costs for the user. Today few low cost methods exists in order to precisely detect single misfires in real time, the majority in fact require the use of expensive sensors (e.g. pressure sensors) or dedicated circuits (e.g. ionization current sensing). This work describes a method and electronic system capable of detecting misfires with good accuracy, using parameters such as the speed sensor signal, already available in commercial engines. The proposed method…

A more reliable relation between Angström and Linke atmospheric turbidity parameters

Abstract This work analyses the correlation between Angstrom and Linke atmospheric turbidity parameters (β and T ) which are commonly used in studies about the atmosphere's behaviour since they efficaciously monitor a point turbidity state and model the aerosol attenuation of solar radiation. Starting from the usual linear relation β = a + bT , a more reliable one is here derived by hourly data of three coastal locations with typical Mediterranean meteoclimatic characteristics, for values of the experimental ratios of diffuse and global solar radiation ⩽0.3. The expression found notably differs from the starting one as shown by the time variable.

Demand side management and Distributed on Site actions benefits

Global warming and energy demand are nowadays becoming one of the major issues of the third millennium, mainly because human activities seem to have a clear impact on the raise of CO2 emissions as never it has been experienced in the past. Among the different factors affecting CO2 emissions, energy demand from buildings constitutes one of the most important actors. Energy Management (EM) actions can reduce the energy consumption of the system and minimize peaks-level, by using a distributed control over every house. These local actions can greatly contribute to reduce the impact on the global CO2 emissions. An evaluation of the potential energy saving and CO2 emissions reduction on building…

L'integrazione degli impianti ad aria con soffitti radianti nelle degenze ospedaliere: un caso studio per la valutazione delle condizioni di benessere termico

Nel presente lavoro vengono descritti i risultati di una ricerca sperimentale, condotta in periodo estivo, sulle prestazioni di comfort termico in degenze ospedaliere climatizzate mediante impianti ad aria primaria e sistemi radianti a soffitto. La ricerca sperimentale, sviluppata grazie alla collaborazione tra le Università di Ferrara, Bologna e Palermo ed una azienda produttrice di sistemi radianti a soffitto, è stata condotta all’interno di due stanze di degenza presso il reparto Maternità dell’Ospedale Maggiore di Bologna. La scelta del luogo è motivata dal fatto che è sempre maggiore l’attenzione della letteratura verso gli standard di comfort che devono essere garantiti nell’ambito os…

Low Cost Electrical Current Sensors with Extremely Wide Measurement Range

A new electrical current measurement system is presented. It features the ability to dynamically and automatically change its measurement range to the sensed current amplitude without user action. It also exhibits galvanic isolation and near zero insertion loss characteristics.

Reconfigurable digital instrumentation based on FPGA

A novel application of FPGA to realize digital test equipment is proposed. It takes advantage of the dynamic reconfigurability of FPGAs so easily tailoring custom test functions in the same instrument. This results in high effective, compact and low cost instruments.

Responsivity measurements of N-on-P and P-on-N silicon photomultipliers in the continuous wave regime

We report the electrical and optical comparison, in continuous wave regime, of two novel classes of silicon photomultipliers (SiPMs) fabricated in planar technology on silicon P-type and N-type substrate respectively. Responsivity measurements have been performed with an incident optical power from tenths of picowatts to hundreds of nanowatts and on a broad spectrum, ranging from ultraviolet to near infrared (340-820 nm). For both classes of investigated SiPMs, responsivity shows flat response versus the optical incident power, when a preset overvoltage and wavelength is applied . More in detail, this linear behavior extends up to about 10 nW for lower overvoltages, while a shrink is observ…

Smart plugs: A low cost solution for programmable control of domestic loads

International audience; Balancing energy demand and production is becoming a more and more challenging task for energy utilities. This is due to a number of different reasons among which the larger penetration of renewable energies which are more difficult to predict and the meagre availability of financial resources to upgrade the existing power grid. While the traditional solution is to dynamically adapt energy production to follow the time-varying demand, a new trend is to drive the demand itself by means of Direct Load Control (DLC). In this paper we consider a scenario where DLC functionalities are deployed at a large set of small deferrable energy loads, like appliances of residential…

On the Fidelity of IEEE 802.11 commercial cards

The IEEE 802.11 D CF protocol is known to be fair in terms of long-term resource repartition among the contending stations. However, when considering real scenarios, where commercial 802.11 cards interact, very unpredictable as well as sometimes surprising behaviors emerge. Motivation of this paper is to investigate the reasons of the very evident disagreement between the theoretical IEEE 802.11 DCF protocol models and its practical implementations. Inparticular, we try to characterize the card behavior not only in terms of perceived throughput, but also in terms of low-level channel access operations. In fact, the simple throughput analysis does not allow to identify what affecting paramet…

PROGETTO DI FILTRI EMI PER CONVERTITORI DC/AC AD ELEVATA POWER DENSITY

Il lavoro tratta del progetto di filtri EMI per convertitori DC/AC ad elevata power density

Design and realization of a portable continuous wave fNIRS

A design and implementation of a portable functional Near InfraRed Spectroscopy embedded system prototype is described. In this theoretical and experimental work, we present an embedded system hosting 64 LED sources and 128 Silicon PhotoMultiplier detectors (SiPM). The elementary part of the structure is a flexible probe “leaf” consisting of 16 SiPMs, 4 couples of LEDs, each operating at two wavelengths, and a temperature sensor. The hardware system is based on an ARM main microcontroller that allows to perform both the switching time of LEDs and the acquisition of the SiPM outputs. The performed preliminary experimental tests achieved very promising results, thus demonstrating the effectiv…

High Resolution Time Domain Reflectometry for Dielectric State Monitoring in High Voltage Cables

A high resolution Time Domain Reflectometry system has been designed in order to investigate the possibility of measuring with good accuracy the dielectric properties of high voltage cables insulator materials by means of Time-of-Flight measures. The system employs a dedicated Time-To-Digital Converter in order to achieve a time resolution of 90 ps. By exploiting averaging techniques the resolution has been further increased. Experimental results showed the possibility of measuring the dielectric constant with a resolution of 0.03%.

Electro-optical characterization of new classes of Silicon Carbide UV photodetectors

In this paper, we present the fabrication process steps and the characterization of 4H-SiC vertical Schottky UV detectors, where interdigitated strips, acting as top metal contacts, have been realized in $\hbox{Ni}_{2}\hbox{Si}$ . These devices exploit the pinch-off surface effect. $I$ – $V$ and $C$ – $V$ characteristics, as functions of temperature, were measured in dark conditions. In addition, we have carried out responsivity measurements, for wavelengths ranging from 200 to 400 nm, at varying package temperature and applied reverse bias. A comparison among devices having different strip pitch sizes has been performed, thus finding out that the 10- $\mu\hbox{m}$ pitch class demonstrates …

Preservation of the artistic heritage within the seat of the Chancellorship of the University of Palermo

The correct maintenance of artworks of historical and artistic value requires a wide and detailed analysis of all the information relevant for preserving them, such as identification of the main deterioration factors, knowledge of the climatic history of the object, set-up of measuring methods and statistics of the guide parameters, and definition of a set of recommended environmental aspects to be controlled within a stable climate condition linked to the particular kind of object or its surface. In Italy, the basic laws UNI 10829 and UNI 10969 impose a reference methodology for the in-field measurement and data analysis. This paper reports the first results of a measuring campaign, carrie…

Thermal characterisation of Bio Based Building Materials

This paper describes how the characterization of indigenous renewable biomass sources that are applicable for making bio-based building (BBB) materials is crucial as it can significantly affect the cost of production and the quality of material. Nowadays, in any specific area, wide ranges of biomass sources are usually available but only a few sources may be suitable for making BBB material. Therefore the suited sources should be determined. In this paper, the use of BBB materials is focused on Insulation Materials which are widely used in the buildings. Compared with currently used materials, these materials are bio-degradable. Insulation material with a good energy-adsorbing property and …

Algorithms for the calculation of the view factors between human body and rectangular surfaces in parallelepiped environments

Abstract The thermal comfort conditions for people in moderate thermal environments are subjected to spatial changes, depending on the radiative exchanges of the human body with the surrounding surfaces. Radiative thermal exchanges are notably accounted for by means of the “view factors” between a person in a given posture and the surface of the enclosure. These important parameters can be evaluated by means of a large set of graphs by Fanger, for rectangular surfaces. But the handling of graphs could lead to reading errors. In this paper a simple algorithm is presented, which is able to compute the required view factors. A validation, by means of a comparison against experimental data, is …

A correlation linking the predicted mean vote and the mean thermal vote based on an investigation on the human thermal comfort in short-haul domestic flights

Abstract The results of an experimental investigation on the human thermal comfort inside the cabin of some Airbus A319 aircrafts during 14 short-haul domestic flights, linking various Italian cities, are presented and used to define a correlation among the predicted mean vote (PMV), a procedure which is commonly used to assess the thermal comfort in inhabited environments, and the equivalent temperature and mean thermal vote (MTV), which are the parameters suggested by the European Standard EN ISO 14505-2 for the evaluation of the thermal environment in vehicles. The measurements of the radiant temperature, air temperature and relative humidity during flights were performed. The air temper…

Flexible Laser Tracing Systems for Defining Thin Film Hybrid Geometries

A recent programme of technical collaboration between Alelco, DIE of Palermo and CRES of Monreale has led to the development and operative confirmation of a technique for delineating conductive microgeometries on various types of Substrates. This technique, using a flexible System of laser microlithography on planar (2-D) or three-dimensional (3-D) surfaces, has led to the development of several types of thin film components for use at both low and high frequencies. © 1994, MCB UP Limited

Technologies for the fabrication of cylindrical fine line devices

Abstract A microlithographic process suited for metal patterning on cylindrical substrates has been developed. This includes all steps from metal coating to final etching, with resolution in the 5 μm range.

Chemical Bath Deposition as a Simple Way to Grow Isolated and Coalesced ZnO Nanorods for Light-Emitting Diodes Fabrication

A way to grow and characterize isolated and coalesced ZnO nanorods on $p$ -GaN/sapphire structure is presented. Chemical bath deposition can be used to grow ZnO nanorods of device-quality, simply controlling the duration time of the growth process and the concentration of the nutrient solution in the bath. Increasing the duration of the process, as well as the concentration of the solution, leads to compact and sound layers instead of separated nanorods. However, too high concentrations stop the growth process. Light-emitting diodes fabricated on these ZnO-p-GaN heterostructure have a peak of electroluminescence at 400 nm and exhibit interesting electrical and optical properties. Optical po…

A Proposed Methodology to Control Body Temperature in Patients at Risk of Hypothermia by means of Active Rewarming Systems

Hypothermia is a common complication in patients undergoing surgery under general anesthesia. It has been noted that, during the first hour of surgery, the patient’s internal temperature (Tcore) decreases by 0.5–1.5°C due to the vasodilatory effect of anesthetic gases, which affect the body’s thermoregulatory system by inhibiting vasoconstriction. Thus a continuous check on patient temperature must be carried out. The currently most used methods to avoid hypothermia are based on passive systems (such as blankets reducing body heat loss) and on active ones (thermal blankets, electric or hot-water mattresses, forced hot air, warming lamps, etc.). Within a broader research upon the environment…

FPGA based digital lock-in amplifier for fNIRS systems

Lock-In Amplifiers (LIA) represent a powerful technique helping to improve signals detectability when low signal to noise ratios are experienced. Continuous Wave functional Near Infrared Spectroscopy (CW-fNIRS) systems for e-health applications usually suffer of poor detection due to the presence of strong attenuations of the optical recovering path and therefore small signals are severely dipped in a high noise floor. In this work a digital LIA system, implemented on a Zynq® Field Programmable Gate Array (FPGA), has been designed and tested to verify the quality of the developed solution, when applied in fNIRS systems. Experimental results have shown the goodness of the proposed solutions.

A Novel Wireless Sensor Network for Electric Power Metering

Wireless sensor network with lightweight and efficient communication infrastructures are today a great interest, both at research and industrial level, as they are the basis for reliable monitoring services. Mesh networks are ideal candidates in this scenario, as they can be very fault-tolerant. After introducing wireless network systems requirements, we show the design of a mesh network routing protocol based on AODV schemas. Its implementation runs on top of low-cost off-the-shelf components, and allowed us to build a custom power meter wireless sensor node.

An FPGA-Based Adaptive Fuzzy Coprocessor

The architecture of a general purpose fuzzy logic coprocessor and its implementation on an FPGA based System on Chip is described. Thanks to its ability to support a fast dynamic reconfiguration of all its parameters, it is suitable for implementing adaptive fuzzy logic algorithms, or for the execution of different fuzzy algorithms in a time sharing fashion. The high throughput obtained using a pipelined structure and the efficient data organization allows significant increase of the computational capabilities strongly desired in applications with hard real-time constraints.

SNR measurements of silicon photomultipliers in the continuous wave regime

We report on our Signal-to-Noise Ratio (SNR) measurements carried out, in the continuous wave regime, at different frequencies and at various temperatures, on a novel class of silicon photomultipliers (SiPMs) fabricated in planar technology on silicon p-type substrate. SNR of SiPMs is given by the ratio of the photogenerated current, filtered and averaged by a lock-in amplifier, and the Root Mean Square (RMS) deviation of the same current. In our measurements, we have employed a 10 Hz equivalent noise bandwidth, around the lock-in amplifier reference frequency. The measured noise takes into account the shot noise, resulting from the photocurrent and the dark current, while background light …

Pathological voice analysis via digital signal processing

The interest in pathological voice analysis for specific neurological diseases is growing up aiming to offer more Health-care tele monitoring services since new high performing electronic devices are available for the end-user. In this article we show some parameters that can be digitally extracted and analyzed from pathological voices, in order to find a distinctive sign of the Parkinson disease. As a result, we will show a parameter that gives some information about the Parkinson disease characterization, particularly for male patients. We will also discuss about the needed computational cost related to parameters extraction and elaboration, aiming to target a possible tough yet portable …

Experimental determination of natural air ventilation rates based on CO2 concentration

This study reports the first results of a survey carried out by the authors on a hall used for conferences, training courses, seminars, and aimed to determine the correlation between the concentration of CO2 and the number of air changes only through natural ventilation. The assessment of ventilation rates was based on the knowledge of the indoor and outdoor CO2 concentrations and of the number of people in the hall. As it is known, the CO2 concentrations can be used as an index for the number of people present in a room and can be evaluated as a function of time by using the Meckler equation in steady-state conditions. In that case it is however necessary that some restrictive hypotheses a…

An Optimization Device for Series Parallel Connected PV Plants

In this paper it is presented a testing prototype of a reconfiguration system for photovoltaic (PV) plants. The system enables to increase the total energy output by reducing the electrical mismatch between the PV array modules. The architecture of the implemented switching matrix, performing the dynamic electrical interconnections of the PV panels, enables to reconfigure nine solar modules in a series-parallel (SP) configuration. The contribution is organized as follows. A brief state of the art is first presented, followed by a comparison between the SP and Total-Cross-Tied (TCT) connections. The prototype then is thoroughly described as well as the main design choices. Finally some tests…

An embedded diagnostic system for wheelchairs brushless drives monitoring

The implementation of a microcontroller based monitoring system for the diagnosis of a brushless synchronous motor drives is presented. It finds its primarily interest on motorized wheelchair for disabled people. The embedded system mainly controls all the principal parameters of the electrical drives together with the power supply system. Pre-failure and failure conditions are routinely logged and, depending on the malfunction severity, alarm messages are created and sent to a remote base station by using the GSM wireless network.

Efficient FPGA Implementation of an Adaptive Noise Canceller

A hardware implementation of an adaptive noise canceller (ANC) is presented. It has been synthesized within an FPGA, using a modified version of the least mean square (LMS) error algorithm. The results obtained so far show a significant decrease of the required gate count when compared with a standard LMS implementation, while increasing the ANC bandwidth and signal to noise (S/N) ratio. This novel adaptive noise canceller is then useful for enhancing the S/N ratio of data collected from sensors (or sensor arrays) working in noisy environment, or dealing with potentially weak signals.

Physiological parameters measurements in a cardiac cycle via a combo PPG-ECG system

In this paper, we present an innovative way to measure some physiological parameters (such as the pre-ejection period, the pulse transit time, the blood pressure) in a cardiac cycle. A combo PPG-ECG system has been developed and employed to extract both the ECG signal from standard limb leads and simultaneously the photoplethysmography signal from the wrist and the forearm, to calculate the pre-ejection period. This system represents an easy and non-invasive technique to determine these biomedical parameters without using expensive impedance cardiography equipment.

Copper patterning on dielectrics by laser writing in liquid solution

A technique suitable for laser induced deposition of copper on LiNbO 3 and glass is presented. Deposition is achieved from Cu salt solution mixed with glycerol, after coating the surface with a very thin metal film. High resolution and low electrical resistivity can be achieved, using laser power levels in the 20-mW range. The technique can be used for electrode and interconnect fabrication in integrated optical devices, as well as mask repair or microelectronics applications.

Ventilation Rates and Unsatisfied Percentage from Indoor CO2 Concentration

This work reports the results of a survey carried out on a hall in a historic building in Palermo (Italy) with the aim of assessing the air quality by means of objective measurement of carbon dioxide (CO2) concentration and its subjective evaluation through a questionnaire. The measured values of CO2 concentration were compared with those evaluated using the Meckler equation under steady-state conditions, having verified necessary parameters such as the constancy of the indoor and outdoor CO2 levels and the uniformity of the CO 2 generation rate for all the occupants. The positive correspondence between measured and calculated results allowed us to utilise, under differing circumstances, t…

On the reliability of ASHRAE conduction transfer function coefficients of walls

The transfer function method recommended by the ASHRAE can be considered the most modern tool currently available for the thermal analysis of a building. It is particularly well suited for use with a computer as it makes it possible to describe with great accuracy the internal heat gain of walls using a small set of coefficients. The present paper shows how to calculate sets of coefficients diverse from that proposed by Mitalas who first developed the method and on the basis of an unequivocal criterion, to prove the advantages in using them. The authors also investigated some of the paramount mathematical and physical aspects which affect the approximation degree of the ASHRAE method and, w…

A survey on the thermal conditions experienced by a surgical team

The complex environment of the operating theatre is shared by a group of people having highly different needs: on one side, there is a surgical team whose work may last many hours and, on the other, an anaesthetized patient often subject to liquid infusion. Up to now, little consideration has been given to the different needs of the surgical team who may be affected according to their positions with respect to the scialytic lamp and their particular task. Clothing influences the comfort of the surgical team to a considerable degree: in fact, in some surgery (orthopaedics, neurosurgery and so on), surgeons and assistants must wear paper overalls beneath non-breathable plastic overalls and p…

Performance evaluation of non volatile memories with a low cost and portable automatic test equipment

This paper presents a versatile and portable test equipment, called portable ATE for research and development of non-volatile memories functionalities. The system is based on STM32-NUCLEO assembled with a custom designed daughter board, in order to host non-volatile memories test-chips, to manage the needed power supplies and generate suitable signals stimuli for correct operations. The system is controlled and programmed by a personal computer, via USB interface. In particular the system can perform: memory reading, writing and erasing, with settings flexibility on time and voltage levels; Electrical Stress Tests (Drain, Gate and Bulk Stress); Cycling Tests; debugging algorithms (erase or …

Design and Implementation of an Electronic Control Unit for a CFR Bi-Fuel Spark Ignition Engine

In this work an Electronic Control Unit for the management of a CFR engine will be described. The engine, which is used both for fuel octane rating (both in terms of RON and MON) and for research purpose, is equipped with a double injection system, with the aim to independently operate both with liquid and gaseous fuels. The developed ECU, hence, is able to control the injections of both kind of fuel, together with the spark ignition. Furthermore the system is also able to measure fuel’s consumption, instantaneous engine speed of rotation and air-fuel ratio, showing all the running parameters both on a local LCD display and on a PC based graphical user interface.