Applied Acoustics course (6 CFU)

In academic year 2016/2017 this course is taught in English
by the visiting professor Filippo Maria Fazi, associate professor of Acoustics at the University of Southampton (UK), ISVR

Post-Graduate (Advanced) Degrees: Telecommunication Engineering, Electronics Engineering, Computer Engineering, Mechanical Engineering, Civil Engineering, Environment and Land Engineering, Physics


Teaching Hours:    Tuesday, 14.30 - 18.30 - Plesso Q02

Beginning of the course: 04 October 2016

Lecturer: prof. Filippo Maria Fazi

E-MAIL: filippo.fazi@soton.ac.uk

Website: http://www.southampton.ac.uk/engineering/about/staff/fmf205.page

Receiving hours: Tuesday, 10:30 to 12:30 - building 7 (not recommended - better to use email).

Phone Number: 0521-905854 (not recommended)

Contents

 

Introduction

The objective of this course is to introduce the fundamentals of a broad variety of topics related to acoustics, with a balanced combination of theory, experimental measurements, numerical simulations and computer programming. Students who will successfully complete this module will be able: - To explain the theoretical fundamentals of a number of topics related to acoustics, as listed in the extended programme above - To understand and be able to use the technical language used in scientific literature of acoustics - To apply engineering acoustic knowledge and calculation formulae to the solution of a number of simple acoustic problems - To design and to apply a number of signal processing algorithms to acoustic and audio signals (using MATLAB) - To use (at a basic level) a number of commercial software packages for acoustic simulations and signal processing - To perform some acoustic measurements - To interpret results of acoustics measurements and of plots and graphs related to acoustic phenomena

This year the course is taught by prof. Fazi, an internationally-recognized expert of Acoustics, who will employ a didactical approach typical of the English universities. Lessons and exams will all be in English, of course, but prof. Fazi is an Italian mother tongue, so in case of necessity students can communicate in Italian with him.

This is the occasion for students to learn Acoustics in a way usually impossible in the Italian universities, being projected at the forefront of the best knowledge and technology available worldwide. The ISVR is the temple of Acoustics, and having here one of their best professors is an occasion for everyone wanting to learn the basis of a science which can easily turn out in a successful job and career. The world has a desperate need of good acousticians, and Italy is one the countries where there is more need. And this applies to any branch on Engineering and Physics, but also to Architecture and Environmental Sciences...

The details of the course are yet largely to be defined. This page is here just for providing continuity for students of previous years, as the former teacher of this course, prof. Angelo Farina, will be in Sabbatical Retirement since September 2016 until 28 February 2017.

Students of the previous years and students taking the occasion of following the course in 2016-2017 are suggested to refer to the official web page of this course (yet to be completed, but work is in progress).

 


Program of the Applied Acoustics course (temptative)  

  • Physical Acoustics: Definition of quantities. Propagation of mechanical disturbances in an elastic medium. Sound pressure and particle velocity. The speed of sound. The wave equation. Sound intensity and sound energy density. Active and reactive intensity. Propagating and stationary sound fields.
  • Psychoacoustics: Physiological and psychological mechanisms of sound perception by humans. The logarithmic scale of decibels (dB), elementary operations on quantities expressed in dB. Frequency weighting curves. Masking phenomena in time and in frequency. Audio compression algorithms based on psychoacoustic principles.
  • Sound Propagation: Plane waves, spherical waves, standing waves. Sound reflection and absorption. Sound propagation outdoor. Room acoustics: reverberation, sound quality in concert halls and opera houses, ISO3382 acoustical parameters. Advanced methods for impulse response measurement.
  • Digital Signal Processing applied to audio and acoustics. Fundamentals of spectral analysis and Fourier transform. Sampling of signals. The DFT and the FFT algorithms. Convolution. FIR and IIR filters, calculation of Inverse numerical filters. Active control of sound. Auralisation. Virtual acoustics and 3D audio.
  • Electroacoustics and instrumentation for acoustic measurements: Acoustic transducers (microphones, loudspeakers). Devices for processing analog and digital acoustic signals: amplifiers, equalizers, reverbs, compressors, etc... Sound level meters, spectrum analysers, impulse response measurement systems. Virtual Instrumentation on PC and software for acoustical measurements, with practical exercises in the laboratory.
  • Techniques for numerical simulation of sound propagation: Fundamental of finite element methods, boundary element methods, and ray tracing.

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Method of Examination

The assessment consists of two separate tests:

1) a written examination, consisting of a number of exercises. Some students may be exempted from the written test, on the basis of the results obtained during in-class tests.

2) Oral examination, which focuses mainly on theoretical topics, and which can be accessed only after passing the written test
 

Written exam

All the student must be present at the nominative call at 09.00, and they must sign the presence sheet when called. Who misses this will not be verbalized, and hence he will have to repeat the exam during the following appeal. Who is late at the nominative call looses the right to be examined in that day.

For the written exam, the student is required to carry just a pen and an handheld calculator, as well as charts, tables, notes, etc...

During the written exercises it is possible to employ all of the above material, including notes and/or textbooks; instead, during the final oral exam, the student is not allowed to consult his/her notes or books, but he/she can still employ charts and tables - so it is advisable to keep them separate from the notes.

The usage of computers, tablets, smartphones or the like is strictly forbidden during examinations.

If the student carries such devices with him/her, including cell phones or smartphones, the devices must be kept switched off (NOT just in standby mode) during the whole duration of the exam.

Who infringes this rule will be immediately expelled from the classroom and consequently rejected, even if the device was not being used.

Exception to this rule is allowed only for students with certified Learning Disabilities (LD, DSA in Italian), who are invited to contact the teacher before the exam, possibly by Email or in person, instead of passing through the LD Office "Le Eliche".

For the written exercises, each student is given two pieces of paper: the examination form, which includes the problems and there are spaces for writing the results, and one 4-faces "protocol" foil, where the student should write clearly the passages required for getting the solutions. Both sheets must carry, since the beginning of the exam, name, surname, matricula and signature of each student. It is forbidden to write on anything else than the "protocol" sheet: if one is not enough, additional "protocol" sheets can be asked to the examiner. All the "protocol" sheets must be given back together with the examination form.

The written exercises typically provide a maximum score of 30 points. At least 18 points are required for passing the written exercises and being admitted to the subsequent oral question.

At least one written exercise is always mandatory.

For optimal training to the exercises, it is strongly discouraged to "study" the solution of already-solved problems. The only way to be trained correctly is by attempting to solve problems without any preliminary knowledge of the correct solution. For this, it can be useful to download the text of the problems which were employed in past years, which can be downloaded here:

   OLD EXAM EXERCISES
 

 

Oral exam

Each oral exam is typically shorter than 15 minutes.

It is always mandatory to satisfactorily answer to at least one oral question, typically on theoretical topics, even for students who passed the written exercises with maximum score.

The evaluation of the oral examination, which usually is positive, in some cases can provide a NEGATIVE score, reducing the score obtained in the written part.

So students must train themselves to sustain a formal oral examination on theoretical topics, and are discouraged to only train on exercises.

During the oral examination it is not usually required to do numerical computations: however it is always useful to keep the handheld calculator at hand.

All students are requested to use English both for the written and oral parts of the examination.

For optimal training to the oral examinations, students are encouraged to assist to the previous session of exams.


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Dates of exams (yet to be fixed)

Date

Day

Hour

Place

 

 

 

 

Currently, the Easytest software does not allow to plan the exam dates and classrooms with large advance, so the students are kindly requested to be patient, and do not stress the teacher asking to fix the exam dates. This is currently outside the control of the teacher, and such requests are absolutely not useful.

The students are simply recommended to check this web page often, when the dates are fixed they will be posted immediately here. In any case, the teacher will not answer to requests of fixing additional exams, as it is possible to make exams every week, during the receiving hours, as explained below.

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Electronic registration of exams

Starting in January 2015, the standard procedure for registering exams during the official exam dates shown above is the electronic one, employing ESSE3 (https://unipr.esse3.cineca.it).

This means that every student must obligatorily enlist for the exam on Esse3. And for doing that, the student must have got an approved study's plan, and must have completed the evaluation questionnaire for this course.

Students who cannot enlist on Esse3 cannot make the exam: in no case the teacher will perform manual verbalization or wait to register the exam until a following exam session. Please contact the didactical secretary (ex Presidence office, didactical building) for problems with Esse3, and not the teacher, who has no control on that system.

Being more clear: even if the secretary tells that they cannot solve the problem and to contact the teacher, this does not means that the teacher can accept students who are not enlisted to ESSE3 during official exam dates. In these dates, due to the large number of students, electronic registration only is allowed, and this requires that the students are enlisted on ESSE3.

If, for any reason, the student cannot do that, there is no point contacting the teacher, as he cannot do anything for solving this problem.

 

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Recommended textbooks

The recommended textbooks for an introduction to this topic are:

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"On line" notes (in English)

A good set of notes written in American English, covering the first half of the course (Noise Control) are available from the site of prof. J. S. Lamancusa at Penn State University: http://www.me.psu.edu/lamancusa/me458/ Please, have a look at the animations on that page!

In particular, the first 10 notes, albeit not in the same order, cover perfectly the first part of this Applied Acoustics course.

Penn State notes

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Software

This is the list of software used during the lessons and lab sessions, with links to download them.

Name

Description

Link

 Adobe Audition

Program for sound recording and playback, waveform editor, simple FFT analysis, sonogram, multitrack recorder, and it can act as a "host" program for plugins in three different formats (VST, Direct-X, XFM).

The recommended versions are 1.5 (the best one) and 3.0 (if you need ASIO). An unrestricted version of Audition 3.0 can actually be downloaded for free from the Adobe web site, after registering.

Please DO NOT USE version 2.0 or version CS 5.5 and following, as these are NOT compatible with Aurora plugins. And please, install the English version of Audition (and of any other program offering a multi-language interface!).

Furthermore, it is always mandatory to set the Regional Settings of your operating system (in Control Panel) to English-UK or similar, NEVER in Italian! This affects decimal separator, date, time and number formats... If this setting is incorrect, operations such as Copy and Paste to another program (i.e., Excel) are going to fail....

http://www.adobe.com/it/products/audition/

 Aurora

Suite of XFM plugins for Adobe Audition: generation of test signals (MLS, sweep) computation of the impulse response, acoustic parameters according to ISO 3382, calculation of inverse filters. Includes a fast convolution module, which is employed for performing auralization. 

See the warnings above for Audition regarding program version and regional settings.

Aurora is shareware, with a "russian roulette" annoying-by-purpose feature.

http://www.aurora-plugins.it

 AudioMulch

VST-Host general purpose program, programmable through the construction of block diagrams, coming with a wide range of effects. Easy to use. Versions for Windows and Mac.  90 days free trial.

http://www.audiomulch.com

 Plogue Bidule

VST-Host general purpose program, programmable through the construction of block diagrams, coming with a wide range of effects. It is possible to create new effects. Shareware. Windows and Mac versions. It can also be used as a VST plugin inside another VST Host program. More tricky than Audio Mulch, but also more powerful.  90 days free trial.

http://www.plogue.com/

 SynthEdit

VST-Host program and compiler of VST plugins, programmable through the construction of block diagrams. Customizable interface with editable "skins". Contains an extensive library of graphical objects and of processing functions. Shareware. Better than Labview ....

http://www.synthedit.com/

 SpectraRTA

Spectral analysis in octaves, third octaves, and FFT, signal generator for acoustic testing, measurement of the reverberation time. Works with one or two channels, can be used to record and analyze WAV files.

http://www.soundtechnology.com/

 SpectraPLUS

FFT and fractional-octave frequency analysis, cross-spectrum, sonogram, waterfall, signal generator for acoustic testing, measurement of reverberation times. Works with one or two channels, can be used to record and analyze WAV files. 30 days free trial.

http://www.spectraplus.com/

 Ramsete

Simulation of sound propagation in enclosed spaces and outdoors. Calculates the impulse response, and from it derives all the acoustical parameters. Includes a 3D CAD design module and a module for mapping results in colour or by isolevel curves. It also allows for the export of impulse responses in WAV format, for performing auralization. Free trial of the "Lite" version, the crack can be found on Emule, enabling full performance.

http://www.ramsete.com

 Comsol

"Multiphysics" FEM simulator, which includes modules for Acoustics and Vibration. It allows for the study of wave type phenomena (resonance, interference, diffraction, etc..) at low and medium frequencies, using the Finite Elements method. Free trial license available for students.

http://www.comsol.com

 DISIA

The package includes Citymap and Disiapyr. These are programs for simulation of noise from road and rail traffic, which can operate both on a large scale (Citymap), and for detailed simulations (Disiapyr). They were developed as part of a DISIA project, funded by the Ministry of Environment, and are the reference computational models for the Italian fleet of vehicles. Free for academic usage (password required).

http://pcfarina.eng.unipr.it/Public/DISIA

Note: the above software is commercial software or shareware (excluding the last one, which is free, but the use is restricted to institutional goals of public administrations, and protected by password), although most of them provide a free running mode for a limited period of time, or indefinitely but with reduced functionality. Users who do not like this approach, can use the following open-source software:

  Audacity

Simple "open source" program for sound recording / playback, with many editing effects; it also operates in multitrack. Supports all platforms (Windows, Mac, Linux). A port of Aurora plugins for Audacity is under development (thesis available).

A special version of Audacity containing some of the Aurora modules so far developed can be downloaded HERE.

Please note that these Aurora modules DO NOT WORK on other versions of Audacity...

http://audacity.sourceforge.net/

 

http://pcfarina.eng.unipr.it/Public/Aurora-for-Audacity/

  Sonicbirth

Compiler for VST and AudioUnit plugis for Mac platform, with graphical interface of "block diagram" type. Interface customizable using editable "skins". It contains a wide library of graphic objects and processing functions. Similar to Synthedit, but less powerful and versatile.

http://sonicbirth.sourceforge.net/

 RoomEQ

JAVA application for the measurement of the impulse response of a room with Exponential Sine Sweep and calculation of equalization filters for sound systems. It includes a realtime spectrum analyzer, a realtime Sound Level Meter, and a reverberation time measurement module.

http://www.hometheatershack.com/roomeq/

 Psysound

Matlab suite of modules, with user interface developed for processing of audio signals and acoustic analysis of all kinds

http://psysound.wikidot.com/

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Thesis Topics

A variety of thesis topics is available, for all the branches of Engineering. Some are listed below, but others are available, so it is recommended to contact the teacher for more information.

Attention: an Applied Acoustics thesis can only be experimental, and thus requires hard work: so, if you are looking for a "light and fast" thesis, you're in the wrong place ... On the other hand, students making a thesis in Acoustics usually become acousticians and work in this field. An acoustician has no risk of being unoccupied, most students get their job before finishing their thesis...
 

Title

Description

Suggested degree

Digital Audio Amplifier  

Research carried out in collaboration with ASK Industries, Reggio Emilia, looking for a student who is willing to learn programming DSP devices "embedded" in automotive audio amplifiers. The DSP built into the device could be used for active noise cancellation, for dynamically changing the equalization curve and the gain as a function of the background noise, and for the correction of non-linear response of loudspeakers. The student will work as an intern at the ASK Montecavolo (RE), actively participating in the trial, and gaining professional experience in the field, which is extremely useful for subsequent job search.

Electronics, Telecommunications, Computer Science

Vehicle sound system measurement

Research carried out in collaboration with ASK Industries, Reggio Emilia. The purpose is to evaluate the perceived acoustical quality of a "automotive" sound system, based on innovative measurement techniques (STI, AQT, PEAQ) and on listening tests performed within the vehicle or in a special playback room. It employs mono recording techniques, binaural, or array of microphones. Depending on the capacity of the student, he will have to develop "ad hoc" software for measurement or analysis (in Matlab or Visual C), to define new metrics, to analyze statistically the results of subjective tests, and to design new strategies for temporal, spectral and spatial equalization of the sound reproduction system.

Electronics, Computer, Telecommunications, Mechanical

Active Noise Cancellation

Research carried out in collaboration with ASK Industries, Reggio Emilia. The purpose is to design and build a prototype of device, based on DSP, for processing in real time the signal captured by a primary microphone. The filtered signal is output from one or more loudspeakers, creating an antiphase sound field that cancels the original noise. The student must possess the ability to program a DSP (also using high-level interfaces such as "block diagram"), to carry out measurements of impulse response (Aurora) and of spectra (SpectraRTA), and also to work in the workshop in order to build the mechanical components of the device.

Mechanics, Electronics, Computer Science, Information Technology

Analysis of sound quality of bakery products

Research carried out in collaboration with Barilla, Parma. The purpose is the analysis and optimization of the sound created during fracture and / or chewing of bakery products (such as cookies, biscuits, crackers, sticks, etc..). Binaural recordings are employed for objective analysis of the sound produced, and tests with human subjects are performed, in order to operate a collection of questionnaires and obtain an analysis of the subjective sensations evoked while eating these products. 

Mechanics, Mechanical Engineering for the Food Industry, Information Technology, Management

Use of ultrasound in the food industry

Research carried out in collaboration with Barilla, Parma. The goal is to  evaluate the possibility of using a treatment section with ultrasound for sanitizing and / or homogenization of liquid foods, either as a single treatment, or as a treatment subsidiary to other devices. The student must work alongside a research assistant in carrying out experiments on the pilot line and in the analysis of results.

Mechanics, Mechanical Engineering for the Food Industry

Noise analysis of gear pumps

Research carried out in collaboration with Casappa, Parma. The purpose is to develop new methods of signal analysis, applicable to both the noise signal radiated during operation of gear pumps, and to the "pressure ripple" signal detectable in the delivery circuit of the pump. It is expected to obtain useful information in order to identify problems in the pump (diagnostics), and to develop new, more silent pumps and of longer duration.

Mechanical, Electronics

Analysis of the sound generated by old gramophones and radios

Research carried out in collaboration with the House of Sound, Parma. It deals with measuring the sound characteristics of old gramophones or receivers radio, part of the famous Patane' collection. The recordings could be used as such in the exhibition of the House of Sound, or even be "virtualized" making use of advanced techniques of analysis and resynthesis available in the laboratory of virtual reproduction of the House of Sound.

Telecommunications, Computer Science.

Sound reproduction using loudspeaker arrays

Research carried out in collaboration with the House of Sound, Parma. The student will have to create recordings or compositions, mostly of musical events, but also of "special effects", to play on the WFS playback systems available at the House of Sound: the WFS "white room" the "Sonic Chandelier". The student must first acquire an adequate understanding of the physical mechanisms underlying the Wave Field Synthesis, and master the system hardware and software that operate the House of Sound. Then he must create one or more "documentary soundtracks" that will be "projected" at the House of Sound.

Telecommunications, Electronics, Computer Science

Shooting techniques with virtual microphones

Research carried out in collaboration with the RAI Research Centre, Turin. The purpose is the development of a device for recording "live" events such as concerts, sporting events, theatre, etc.., in all cases in which microphones located close the sound sources cannot be employed. The microphone arrays employed are the Holophone and the Eigenmike 32. The student must make a series of test recordings with these devices, process the traces recorded so as to synthesize an adequate number of virtual microphones with suitable directivity and pointing, and manage the organization of special "surround" listening tests with trained listeners specialize, with the goal to identify the best signal processing technique.

Telecommunications, Electronics, Computer

Three-dimensional measurement of impulse responses in theatres and concert halls

Research carried out in collaboration with AIDA Srl, Parma. The purpose is to develop a method of measuring acoustic characteristics of a room, making use of a new portable recording system, equipped with a tetrahedral microphone probe, called Brahma. The student must perform measurements with the "exponential sine sweep" technique in a number of rooms, comparing the results of the new technique with the traditional ones, and employing the results for designing suitable acoustical corrections, when required.

Electronics, Civil, Telecommunications

Porting of Aurora plugins under Audacity

 

The project, recently launched thanks to the activity of research assistant Simone Campanini, aims to rebuild the suite of Aurora plugins ( www.aurora-plugins.com ) as add-on modules for the open-source and cross-platform program Audacity .
The student will have the opportunity to participate in the development of new software modules, operating on the platform of choice (Windows, Mac, Linux) and to test the correct functionality by performing experiments of measurement and listening, and by comparison with the current implementation for Adobe Audition, and with cutting-edge laboratory instrumentation (Audio Precision, Bruel & Kjaer, etc..).

IT & Computer Science Telecommunications, Electronics

Porting of Aurora and X-volver plugins to VST format

 

The project, recently launched thanks to the activity of research assistant Andrea Venturi, aims to rebuild the suite of Aurora plugins (www.aurora-plugins.com ) as additional modules in VST format.
The student will have the opportunity' to participate in the development of new software modules, operating on the platform of choice (Windows, Mac, Linux) and to test the correct functionality by performing experiments of measuring and listening, and by comparison with the current implementation for Adobe Audition, and with cutting-edge laboratory instrumentation (Audio Precision, Bruel & Kjaer, etc..).

IT & Computer Science, Telecommunications, Electronics

Non-destructive analysis of frescoes by acoustic and vibration measurements

Research sponsored by the Cariparma Foundation, Parma. The purpose is to develop a new test method with very small invasiveness, aimed at locating structurally degraded areas in plaster, frescoes, mosaics, and other structures of historical value. The new method makes use of an "exponential sine sweep" signal, in order to operate with very low sound pressure level; an array of loudspeakers focuses sound waves, so that just a restricted area of the surface to be scanned is stressed, and an array of microphones (or a Laser-Doppler velocimeter) is employed in order to determine the vibrational response of a single point of the structure. The student must first operate a verification of the new method on artificial samples in laboratory, and then perform experimental tests "in situ" inside churches and other historic buildings in Parma.

Civil, Mechanical

Development of a sonar system for "sub-bottom profiling"

Research carried out in collaboration with WASS, La Spezia and Livorno. The goal is the development of a low-frequency Sonar system, operating in the audio field (1000-20000 Hz), broadband, in order to obtain a good penetration into the seabed and to view the soil stratigraphy below. The system uses an array of 16 hydrophones and an underwater loudspeaker fed with sine sweep signal. The student will have to make a series of tests in the laboratory, in the test tank and in the sea, in order to validate the operation of the system, and to process the results of the acquired traces in order to obtain three-dimensional images of the stratigraphy of the bottom.

Electronics, Environment and Territory, Computer

Development of a three-dimensional underwater sound recording system

Research carried out in collaboration with AIDA Srl , Parma. The purpose of the research is the development of a device for recording underwater the signals of 4 hydrophones, capable to determine the direction of origin of the sound, to be used for underwater environmental monitoring in marine protected areas. The student must follow the electromechanical development of the prototype and carry out the characterization of performance with in-tank testing and in-sea testing.

Electronics, Environment and Territory, Computer Science, Mechanical Engineering

Development of an "Acoustic Camera" system

Research carried out in collaboration with AIDA srl , Parma. The purpose is to reactivate the "Acoustic Camera" system that was built four years ago, making use of high quality microphones and of a new portable hardware acquisition system, which should allow to be used outside the laboratory. The student must first reassemble the system and make it operational, then verify its performances through a series of measurements to be carried out both in the laboratory, and in industrial environment. If versed in programming, the student may also participate in the development of the new real timea software, that should replace the existing Matlab software, currently capable of "off line " processing only.

Mechanical, Civil, Electronics, Computer Science

Mapping of environmental noise through measurements and simulation

Research carried out in collaboration with the Municipality of Parma, Department of Environment. It is aimed to realize a first prototype of a control unit for acoustic monitoring of urban areas, based on the assembly of already existing, low cost components. The student must make a series of surveys by placing these 10 units in the hot spots of the city, in order to achieve the noise map in the city of Parma, also making use of the simulation software Citymap.

Environment and Territory, Civil

Development of a "low cost" measurement system for building acoustic

Research carried out in collaboration with AIDA srl , Parma. This is to verify the ability to employ low-cost instrumentation, making use of digital audio equipment originally developed in the field of music, to carry out building acoustics measurements, thanks to recent technical rules which allow for the use of the exponential sine sweep signal. This makes it possible to use a small loudspeaker and low-cost digital audio recorders. The student must carry out a campaign of comparative measurements, using either the new method and the traditional one, and compare the results obtained in a number of civil and public buildings (school, hospital, etc..).

Civil, Environment and Territory

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Copyright (C) Angelo Farina - reproduction prohibited without permission.
Last revised: 05/09/2016, 18:06