Index

- Main dates

- Short biography

- Research subjects

- Application subjects

- Academic collaborations

- Teaching and other institutional activities

- Project and laboratory reports

- Publications:

International journal papers

Italian journal papers in English

Italian journal papers in Italian

Transactions of the Istituto Veneto di Scienze, Lettere ed Arti

Transactions of the Accademia Galileiana

Chapters of international research books

Proceedings of international conferences

Books and papers on education and cultural issues

Books on research

Main dates

- Main dates

- Short biography

- Research subjects

- Application subjects

- Academic collaborations

- Teaching and other institutional activities

- Project and laboratory reports

- Publications:

International journal papers

Italian journal papers in English

Italian journal papers in Italian

Transactions of the Istituto Veneto di Scienze, Lettere ed Arti

Transactions of the Accademia Galileiana

Chapters of international research books

Proceedings of international conferences

Books and papers on education and cultural issues

Books on research

Main dates

- 1949: Born in Bolzano, Italy.
- 1967: Classical high school ("liceo classico") certificate (average mark: 8 out of 10).
- 1972: "Laurea" degree in Electrical Engineering, University of Padova, Italy (marks 110 out of 110).
- 1973: Qualification for the profession of engineer.
- 1973-74: Italian air-force corps of electronic engineers.
- 1975: M.Sc. degree in Systems Engineering, University of London (with the Diploma of the Queen Mary College).
- 1976-1978: Scholarship of the Italian Ministry of Higher Education, Institute of Electrical and Electronics Engineering, University of Padova, Italy.
- 1978-1985: Assistant lecturer ("assistente ordinario"), University of Padova, Italy.
- 1985-1994: Associate Professor of Automatic Control, University of Padova, Italy.
- 1994-today: Full Professor of System Theory, University of Udine, Italy.
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Short biography

Umberto Viaro was born in Bolzano, Italy, in 1949.

He obtained the "Laurea" degree in Electrical Engineering with the highest marks from the University of Padova in 1972.

In June 1973 he passed the State examination for the qualification for the profession of engineer.

After attending the air force specialization school (SAAM) in Florence and passing the final examination (average marks 19.66 out of 20), he served as a second lieutenant in the Italian air force corps of electronic engineers (GAri-el) till the end of 1974.

In 1975 he obtained the M.Sc. degree in Systems Engineering from the University of London (winner of a British Council scholarship).

From November 1975 till October 1994 he was first assistant lecturer and then associate professor of Automatic Control at the University of Padova.

Since November 1994 he has been full professor of System Theory first in the Department of Physics (until 1995) and then in that of Electrical, Management and Mechanical Engineering (DIEGM) of the University of Udine (later merged into the Polytechnic Department of Engineering and Architecture - DPIA) of which he was among the founders.

From its inclusion in the Electronics Engineering curriculum in 1995 to 1999 he chaired the Electronics Engineering apprenticeship committee of the Udine University.

During the same period he was a member of the Socrates Committee of the Faculty of Engineering.

From its establishment in the academic year 1999/2000 till January 2006 he coordinated the Ph.D. course in Information and Industrial Engineering held at DIEGM.

From November 2007 to November 2009 he was a member of the evaluation committee ("Nucleo di Valutazione") of the University of Udine.

His recent research activity focuses on the following topics:

(i) optimal model reduction,

(ii) robust control of uncertain systems, with particular regard to standard controller parametrization and tuning,

(iii) switching and LPV control, and

(iii) modelling and control of dynamic networks.

The main application areas of the projects in which he has been recently involved are:

(i) permanent magnet ac motor drives,

(ii) molten steel level control in continuous casting plants,

(iii) planning and control of water distribution networks, and

(iv) feedback control of predator-prey systems.

He has long-standing collaborations with: the control team in Udine (at both DIEGM and the Department of Mathematics and Informatics), the Department of Information Engineering of the University of Padova, and the Systems Research Institute of the Polish Academy of Sciences in Warsaw.

He is the author or coauthor of 89 peer-reviewed international journal papers published outside Italy (in particular, 24 papers in the transactions of the IEEE).

His collaboration with various Italian and international research groups operating in both the industrial and the academic sector is documented by further 25 research papers (9 of them in English) appeared in the main Italian peer-reviewed journals on information science and technology (in particular, 7 in Alta Frequenza), 20 international book chapters, and more than 50 papers in the proceedings of international conferences.

A major result of his 25-year-long collaboration with Antonio Lepschy (1931-2005), one of the founding fathers of the automatic control community in Italy, is the coauthorship of 8 papers (5 in English, 3 in Italian) in the transactions ("Atti") of the Accademia Galileiana in Padova, and 8 (6 in English, 2 in Italian) in those of the Istituto Veneto di Scienze, Lettere ed Arti in Venice.

A further paper in English (item 9 in the list entitled "Transactions of the Istituto Veneto di Scienze, Lettere ed Arti", written in collaboration with D. Casagrande) was presented to the aforementioned academy on January 27, 2018.

He also is the author or coauthor of 4 books and 7 papers on education and cultural issues, and of 2 books on research subjects. In particular, the research activity of Umberto Viaro with Antonio Lepschy is illustrated in his book “Twenty-Five Years of Research with Antonio Lepschy”.

In 1980 he was awarded the AEI-IEL prize for the best paper published in the proceedings ("Rendiconti") of the 1979 annual meeting, devoted to automatic control, of the Associazione Elettrotecnica ed Elettronica Italiana (AEI). In 2017 he was awarded, together with F. Blanchini, D. Casagrande e G. Giordano, the NAHS IFAC Best Paper Award for the triennium 2015-2017.

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- Model reduction: L2 approximation, power equivalent realizations, Maehly and Routh-Padé methods, interpolation techniques, methods aiming at the retention of suitable asymptotic responses, delay approximation by means of feedback.
- Synthesis of robust controllers: analytic stability-margin design for unstable and non-minimumphase plants, synthesis of PID controllers for robust performance, characterization of PID and lead/lag controllers satisfying given H-infinity bounds.
- Switching and LPV control.
- Modelling, analysis and control of dynamic networks: stability, positivity, boundedness, steady state.
- Stability analysis of digital filters: global asymptotic stability regions for direct- and coupled-form filters, detection of limit cycles.
- Stability tests: common setting of recursive stability-test algorithms, their geometrical interpretation, split forms of stability-test algorithms, properties of the Routh algorithm, simple proofs of stability criteria, root clustering.
- Compartment and signal flow graphs: compartment graphs accounting for given dynamic relationships, derivation of transfer-function matrices from graphic representations, relations between graphic representations of systems.
- Finite automata of coding systems: models of coding systems, state observation and error detection analysis, synthesis of spectral densities.
- Feedback in technology and in the sciences of man and society: analysis of the operation of ancient clocks, epistemological and philosophical problems.
- Distribution systems optimization: electric power dispatch, design and control of fluid networks.
- Root loci: invariance property, asymptotic behaviour of locus branches.
- Fractional-order systems: analysis, approximation and control.
- Van der Pol oscillator: phase response curves.

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Application subjects

- Characterization of the electric power demand of composite machine shops.
- Land reclamation systems optimization.
- Optimal power dispatch in large-scale power systems.
- Cement consumption time series analysis.
- Permanent magnet ac motor drives.
- Molten steel level control in continuous casting plants.
- Planning and control of fluid networks.
- Feedback control of predator-prey systems.
- Dynamic race models.
- Control of robotic links.

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Academic collaborations

- Alessandro Beghi, University of Padova, Italy
- Franco Blanchini, University of Udine, Italy
- Elena Borgatti, University of Padova, Italy
- Roberto Caldon, University of Padova, Italy
- Daniele Casagrande, University of Udine, Italy
- Claudio Cobelli, University of Padova, Italy
- Giovanni De Poli, University of Padova, Italy
- Peter Dorato (1932-2010), University of Albuquerque, USA
- Augusto Ferrante, University of Padova, Italy
- Giulia Giordano, University of Udine, Italy
- Wieslaw Krajewski, Polish Academy of Sciences, Poland
- Antonio Lepschy (1931-2005), University of Padova, Italy
- Gian Antonio Mian (1942-2006), University of Padova, Italy
- Fabio Miani, University of Udine, Italy
- Stefano Miani, University of Udine, Italy
- Carlo Maria Monti, University of Padova, Italy
- Gianfranco Pierobon, University of Padova, Italy
- Michela Redivo-Zaglia, University of Padova, Italy
- Giorgio Romanin-Jacur, University of Padova, Italy
- Silvana Stefani, University of Milano-Bicocca, Italy
- Mauro Zigliotto, University of Padova, Italy

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Teaching and other institutional activities

Besides Automatic Control and Systems Theory, taught in partial fulfillment of his teaching mandate, Umberto Viaro was in charge of numerous temporary courses. In particular, he held a course of Probability Theory and Statististics for electrical engineers at the University of Padova, a course of Statistics for students in economics at the University of Bergamo (which led to the preparation of textbook 1 in the following list entitled "Books and papers on education and cultural issues"), as well as the postgraduate course of Statistical Hydrology (twice) at the International Centre of Hydrology of the University of Padova (which led to the preparation of papers 2 and 3 in the following list entitled "Books and papers on education and cultural issues") and a short 2-day course on System Theory for the Technical staff of Danieli Automation S.p.A. in Buttrio, Udine.

He acted either as an expert member or as the chairman of the examining boards in some State examinations (held at the Universities of Padova and Udine) for becoming a professional engineer.

He organised twice the visits and seminars at the University of Padova of Prof. Frank J. Evans, Queen Mary College, University of London, and, also twice, those of Prof. Wieslaw Krajewski, Systems Research Institute, Polish Academy of Sciences, Warsaw. In turn, he visited two times the Systems Research Institute in Warsaw as well as the Electronics Department of the Technical University of Warsaw (director Prof. Chris Malinowski), where he gave seminars on topics of model approximation and forced response decomposition.

He was the chairman of the electronics engineering apprenticeship committee (“Commissione tirocinii”) of the University of Udine for several years after this activity had been included into the engineering curricula, thus taking part in the related tutorials and in the preparation of the standard form of the contracts between the University and the employing companies. These contracts were activated by individual agreements (one for each student) under the responsibility of both a company tutor and a university tutor who collaborated with the student and the company in the solution of technical and didactic problems leading to a thesis to be discussed in a final examination. In particular, he acted as the university tutor for various students working at Danieli Automation S.p.A., Buttrio, and Thermokey S.p.A., Rivarotta di Rivignano Teor. The aforementioned contracts did not call for a remuneration but were mainly intended as a contribution of the University of Udine to the industrial development of the Region. This activity also resulted in some research papers (see item 75 of the list of international journal papers, and items 17, 19, 36, 40 of the list of the proceedings of international conferences).

In the late Nineties he was a member of the Faculty of Engineering in the Socrates Committee of the University of Udine.

He was responsible for the editing of the reports on the activities of the Department of Electrical, Management and Mechanical Engineering (DIEGM) in the first two years after its establishment (1997 and 1998).

He was responsible for the regional project L.R. 3/98 ("bando" 2002) entitled "Applicazione di tecniche di controllo innovative per servomeccanismi ed azionamenti in campo industriale e civile" [Application of innovative control techniques to industrial and civil servomechanisms and drives] which was partly funded by Regione Friuli-Venezia Giulia.

In 2006 and 2007 he was a member of the board for deciding whether some students with a foreign degree could be admitted to an engineering course of the University of Udine.

He was either a member or the chairman of the boards for the final examination of some Ph.D. students at the Universities of Padova, Genova and Udine. In particular, he chaired the board of examiners at the end of the first three-years Ph.D. course (XV cycle) run at DIEGM, University of Udine, of which he was the coordinator in the first 5 years after its establishment. Some of the then successful candidates are now highly-valued researchers in the University of Udine or other university institutions (Profs. Stefano Boscolo Nale, Pierpaolo Palestri, Marco Sortino and Dr. Nicola Serra). He also chaired the board for the final examination of Ph.D. students at DIEGM in 2010. He directly supervised the research work of two Ph.D. students (Drs. Enrico Del Pin and Marco Cilia).

He was a member of the examining boards in some competitions for academic posts at the Universities of Roma “La Sapienza”, Padova and Udine.

He was either a member or the chairman of boards for deciding whether some professors were eligible for tenure.

As already said, from its establishment in the academic year 1999/2000 till January 2006 he coordinated the Ph.D. course in Information and Industrial Engineering held at DIEGM.

From November 2007 to November 2009 he was an expert member of the Evaluation Committee ("Nucleo di Valutazione") of the University of Udine.

Since March 2015 he has been a member of the Disciplinary Board of the Udine University.

In 2011 he acted as a reviewer for the Tubitak (Scientific and Technological Research Council of Turkey) Science award offered to scientists working in Turkey who obtained significant achievements at the international level.

Since 2012 he has been acting as an external examiner of the Ph.D. theses of some doctoral students of the Department of Electrical Engineering, Indian Institute of Technology, Roorkee, India.

He was also a member of some boards for appointing postdoctoral scholars or scientific collaborators.

His laboratory work and his participation in many research projects supported by the Italian Ministry of Research is documented by several technical and scientific reports, most of which were presented at the annual meetings of the Italian control community (formerly CIRA, now SIDRA) and appeared in their proceedings (see section entitled "Project and laboratory reports").

In particular, he participated in the PRIN projects (Research projects of significant national interest) coordinated by G. Picci (1998), A. Vicino (2000), M. Milanese (2002), F. Blanchini (2004) and F. Blanchini (2006).

In 1995 he was among the founders of the Department of Electrical, Management and Mechanical Engineering (DIEGM) of the University of Udine.

On at least two occasions he presented the Faculties of Engineering of the Universities of Padova and Udine to secondary-school students outside the Friuli-Venezia Giulia Region (see, e.g., item 6 in the list of publications on educational issues).

As a part of his collaboration with the Istituto di Idraulica of the Padova University, from 1978 to 1984 he was a reviewer for the journal "Bibliografia Italiana di Idraulica (Hydraulic Italian Bibliography)", published by Centro di Documentazione Idraulica (Centre for Hydraulic Documentation), Univ. Padova (ISSN 0006-1042).

He has been a reviewer for the main international journals and conferences on control and systems theory for many years.

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International journal papers (published outside Italy)

- R. Caldon and U. Viaro, "Modelling of electrical power demand characteristics for composite machine shops", Int. J. Electrical Power and Energy Systems, vol. 4, no. 2, pp. 137-141, 1982.
- A. Lepschy and U. Viaro, "An improvement in the Routh-Padé approximation techniques", Int. J. Control, vol. 36, no. 4, pp. 643-661, 1982.
- A. Lepschy, G.A. Mian, and U. Viaro, "Frequency-domain approach to model reduction problem", Electronics Letters, vol. 18, no. 19, 829-830, 1982.
- A. Lepschy and U. Viaro, "Simulation of complex systems via reduced-order models", Int. J. Modelling and Simulation, vol. 3, no. 2, pp. 65-69, 1983.
- A. Lepschy and U. Viaro, "A note on the model reduction problem", IEEE Trans. Automat. Contr., vol. AC-28, no. 4, pp. 525-527, 1983.
- A. Lepschy and U. Viaro, "Some considerations on nonminimality, ill-conditioning, and instability of Padé approximants", Int. J. Systems Sci., vol. 14, no. 6, pp. 633-646, 1983.
- A. Lepschy and U. Viaro, "Model reduction using the output equation error", Int. J. Systems Sci., vol. 15, no. 9, pp. 1011-1021, 1984.
- A. Lepschy, G.A. Mian, and U. Viaro, "Model reduction in frequency domain: comparison and analysis of different methods", Control and Computers, vol. 12, no. 3, pp. 77-80, 1984.
- A. Lepschy, G.A. Mian, and U. Viaro, "Approximation errors in the computation of Chebyshev expansion coefficients", Electronics Letters, vol. 21, no. 10, pp. 414-415, 1985.
- A. Lepschy and U. Viaro, "Model reduction for control systems with restricted complexity controllers", J. Franklin Inst., vol. 319, no. 6, pp. 559-567, 1985.
- A. Lepschy, G. Romanin Jacur, and U. Viaro, "A procedure to obtain the symbolic expression of input-output representations from a signal flow graph", Control and Cybernetics, vol. 15, no. 3-4, pp. 425-445, 1986.
- A. Lepschy, G. Romanin Jacur, and U. Viaro, "An extension to 'An algorithm for finding a circuit of even length in a directed graph' ", Int. J. Systems Sci., vol. 17, no. 5, pp. 829-831, 1986.
- C. Cobelli, A. Lepschy, G. Romanin Jacur, and U. Viaro, "Symbolic expression of transfer functions in compartmental systems with control", Int. J. Systems. Sci., vol. 17, no. 6, pp. 925- 935, 1986.
- A. Lepschy, G.A. Mian, and U. Viaro, "Comments on 'ARMA spectral estimation of time series with missing observations' ", IEEE Trans. Information Theory, vol. IT-32, no. 4, pp. 601- 602, 1986.
- C. Cobelli, A. Lepschy, G. Romanin Jacur, and U. Viaro, "Compartmental graphs accounting for smoothing, integration and differentiation", J. Franklin Inst., vol. 321, no. 2, pp. 179-188, 1986.
- C. Cobelli, A. Lepschy, G. Romanin Jacur, and U. Viaro, "An expanded schematic for compartmental systems", Math. Biosci., vol. 79, no. 1, pp. 97-106, 1986.
- C. Cobelli, A. Lepschy, G. Romanin Jacur, and U. Viaro, "On the relationship between Forrester's schematics and compartmental graphs", IEEE Trans. Sys. Man Cybern., vol. SMC-16, no. 5, pp. 723-726, 1986.
- A. Lepschy, G.A. Mian, and U. Viaro, "Parameter space quantization in fixed-point digital filters", Electronics Letters, vol. 22, no. 7, pp. 384-386, 1986.
- A. Lepschy, G.A. Mian, and U. Viaro, "Stability analysis of second-order direct-form digital filters with two roundoff quantizers", IEEE Trans. Circuits Syst., vol. CAS-33, no. 8, pp. 824- 826, 1986.
- A. Lepschy, G.A. Mian, and U. Viaro, "A contribution to the stability analysis of second-order direct-form digital filters with magnitude truncation", IEEE Trans. Acoust. Speech Signal Processing, vol. ASSP-35, no. 8, pp. 1207-1210, 1987.
- A. Lepschy, G.A. Mian, and U. Viaro, "A method for optimal linear model reduction", Systems Control Lett., vol. 9, no. 5, pp. 405-410, 1987.
- A. Lepschy, G.A. Mian, and U. Viaro, "System approximation by matching the impulse response energies", J. Franklin Inst., vol. 325, no. 1, pp. 17-26, 1988.
- A. Lepschy, G.A. Mian, and U. Viaro, "Parameter plane quantization induced by the signal quantization in second-order direct-form digital filters with one quantizer", Signal Processing, vol. 14, no. 1, pp. 103-106, 1988.
- A. Lepschy, G.A. Mian, and U. Viaro, "Stability preservation and computational aspects of a newly proposed reduction method", IEEE Trans. Automat. Contr., vol. AC-33, no. 3, pp. 307- 310, 1988.
- A. Lepschy, G.A. Mian, and U. Viaro, "Effects of quantization in second-order fixed-point digital filters with two's complement truncation quantizers", IEEE Trans. Circuits Syst., vol. CAS-35, no. 4, pp. 461-466, 1988.
- A. Lepschy, G.A. Mian, and U. Viaro, "A stability test for continuous systems", Systems Control Lett., vol. 10, no. 3, pp. 175-179, 1988.
- A. Lepschy, G.A. Mian, and U. Viaro, "Zero-state accessibility and stability of optimal coupled-form digital filters with rounding", IEEE Trans. Circuits Syst., vol. CAS-35, no. 5, pp. 590-594, 1988.
- A. Lepschy, G.A. Mian, and U. Viaro, "A geometrical interpretation of the Routh test", J. Franklin Inst., vol. 325, no. 6, pp. 695-703, 1988.
- A. Lepschy, G.A. Mian, and U. Viaro, "A note on line spectral frequencies", IEEE Trans. Acoust. Speech Signal Processing, vol. ASSP-36, no. 8, pp. 1355-1357, 1988.
- A. Lepschy, G.A. Mian, and U. Viaro, "Euclid-type algorithm and its applications", Int. J. Systems Sci., vol. 20, no. 6, pp. 945-956, 1989.
- A. Lepschy, G.A. Mian, and U. Viaro, "Zero-input limit cycles and stability in second-order fixed-point digital filters with two magnitude truncation quantizers", Circuits Systems Signal Processing, vol. 8, no. 4, pp. 427-433, 1989.
- A. Lepschy and U. Viaro, "On the simplification of transfer-function matrices using Padé-type methods", Control and Computers, vol. 17, no. 1, pp. 1-5, 1989.
- A. Lepschy, G.A. Mian, and U. Viaro, "Splitting of some s-domain stability-test algorithms", Int. J. Control, vol. 50, no. 6, pp. 2237-2247, 1989.
- A. Lepschy, G.A. Mian, and U. Viaro, "Common setting for some classical z-domain algorithms in linear system theory", Int. J. Systems Sci., vol. 21, no. 4, pp. 739-747, 1990.
- W. Krajewski, A. Lepschy, G.A. Mian, and U. Viaro, "On model reduction by L2-optimal pole retention", J. Franklin Inst., vol. 327, no. 1, pp. 61-70, 1990.
- W. Krajewski, A. Lepschy, G.A. Mian, and U. Viaro, "A unifying frame for stability-test algorithms for continuous-time systems", IEEE Trans. Circuits Syst., vol. CAS-37, no. 2, pp. 290-296, 1990.
- A. Lepschy, G.A. Mian, and U. Viaro, "An alternative proof of the Jury-Marden stability criterion", Control and Computers, vol. 18, no. 3, pp. 70-73, 1990.
- A. Lepschy, G.A. Mian, and U. Viaro, "Stability regions for second-order fixed-point digital filters in coupled form", Circuits Systems Signal Processing, vol. 9, no. 4, pp. 409-420, 1990.
- A. Lepschy, G.A. Mian, and U. Viaro, "Constrained L2-optimal model reduction", Control and Computers, vol. 19, no. 2, pp. 45-48, 1991.
- A. Lepschy, G.A. Mian, and U. Viaro, "Efficient split algorithms for continuous-time and discrete-time systems", J. Franklin Inst., vol. 328, no. 1, pp. 103-121, 1991.
- A. Lepschy, G.A. Mian, and U. Viaro, "Hermite-type interpolation of squared-magnitude functions", Appl. Math. Comp., vol. 43, no. 3, pp. 265-270, 1991.
- A. Lepschy, G.A. Mian, and U. Viaro, "On rational interpolation with positivity constraints", Circuits Systems Signal Processing, vol. 10, no. 4, pp. 471-483, 1991.
- A. Lepschy, G.A. Mian, and U. Viaro, "Feedback control in ancient water and mechanical clocks", IEEE Trans. Education, vol. 35, no. 1, pp. 3-10, 1992.
- C.M. Monti and U. Viaro, "State observation and error detection analysis in finite automata for coding systems", J. Math. Systems Estimation Control, vol. 3, no. 3, pp. 327-345, 1993 (ISSN 1052-0600).
- C.M. Monti, G.L. Pierobon, and U. Viaro, "Synthesis of spectral densities using finite automata", IEEE Trans. Signal Processing, vol. 41, no. 5, pp. 1993-1996, 1993.
- W. Krajewski, A. Lepschy, G.A. Mian, and U. Viaro, "On flexible model reduction by the modified factor division method", Systems Science, vol. 19, no. 2, pp. 23-36, 1993.
- W. Krajewski, A. Lepschy, G.A. Mian, and U. Viaro, "Optimality conditions in multivariable L2 model reduction", J. Franklin Inst., vol. 330, no. 3, pp. 431-439, 1993.
- A. Lepschy and U. Viaro, "On the mechanism of recursive stability-test algorithms", Int. J. Control, vol. 58, no. 2, pp. 485-493, 1993.
- W. Krajewski, A. Lepschy, and U. Viaro, "Relations among the autocorrelation coefficients of recursively generated digital filters", Archives of Control Sciences, vol. 2 (XXXVII), no. 1-2, pp. 73-83, 1993.
- P. Dorato, A. Lepschy, and U. Viaro, "Some comments on steady-state and asymptotic responses", IEEE Trans. Education, vol. 37, no. 3, pp. 264-268, 1994.
- A. Lepschy and U. Viaro, "Derivation of recursive stability-test procedures", Circuits Systems Signal Processing, vol. 13, no. 5, pp. 615-623, 1994.
- A. Beghi, A. Lepschy, and U. Viaro, "A property of the Routh table and its use", IEEE Trans. Automat. Contr., vol. AC-39, no. 12, pp. 2494-2496, 1994.
- W. Krajewski, A. Lepschy, M. Redivo-Zaglia, and U. Viaro, "Results of the application of an algorithm for L2 model reduction", J. Circuits Systems Computers, vol. 4, no. 3, pp. 295-303, 1994.
- W. Krajewski, A. Lepschy, and U. Viaro, "Reduction of linear continuous-time multivariable systems by matching first- and second-order information", IEEE Trans. Automat. Contr., vol. AC-39, no. 10, pp. 2126-2129, 1994.
- W. Krajewski, A. Lepschy, and U. Viaro, "Approximation of continuous-time linear systems using Markov parameters and energy indices", Archives of Control Sciences, vol. 3 (XXXIX), no. 1-2, pp. 5-14, 1994.
- W. Krajewski, A. Lepschy, and U. Viaro, "Model reduction by matching Markov parameters, time moments, and impulse-response energies", IEEE Trans. Automat. Contr., vol. AC-40, no. 5, pp. 949-953, 1995.
- W. Krajewski, A. Lepschy, and U. Viaro, "Properties of model reduction techniques based on the retention of first- and second-order information", Applied Mathematics and Computer Science, vol. 5, no. 3, pp. 561-571, 1995.
- W. Krajewski, A. Lepschy, M. Redivo-Zaglia, and U. Viaro, "A program for solving the L2 reduced-order problem with fixed denominator degree", Numerical Algorithms, vol. 9, no. 2, pp. 355-377, 1995.
- W. Krajewski, A. Lepschy, and U. Viaro, "Model reduction by reproducing the asymptotic response", J. Franklin Inst., vol. 332B, no. 4, pp. 393-402, 1995.
- A. Beghi, A. Lepschy, and U. Viaro, "Approximating delay elements by feedback", IEEE Trans. Circuits Syst. - Fund. Theory Appl., vol. 44, no. 9, pp. 824-828, 1997.
- A. Ferrante, A. Lepschy, and U. Viaro, "A simple proof of the Routh test", IEEE Trans. Automat. Contr. , vol. AC-44, no. 6, pp. 1306–1309, 1999.
- A. Ferrante, W. Krajewski, A. Lepschy, and U. Viaro, "Convergent algorithm for L2 model reduction", Automatica, vol. 35, no. 2, pp. 75-79, 1999.
- A. Ferrante, W. Krajewski, A. Lepschy, and U. Viaro, "Remarks on the steady-state accuracy of a feedback control system", Control and Cybernetics, vol. 29, no. 1, pp. 51–67, 2000.
- A. Ferrante, W. Krajewski, A. Lepschy, and U. Viaro, "Analytic stability margin design for unstable and nonminimum-phase plants", IEEE Trans. Automat. Contr., vol. 47, no. 12, pp. 2117-2121, 2002.
- W. Krajewski, A. Lepschy, and U. Viaro, "Designing PI controllers for robust stability and performance", IEEE Trans. Control Syst. Technol., vol. 12, no. 6, pp. 973-983, 2004.
- F. Blanchini, A. Lepschy, S. Miani, and U. Viaro, "Characterization of PID and lead/lag compensators satisfying given H-infinity specifications", IEEE Trans. Automat. Contr., vol. 49, no. 5, pp.736-740, 2004.
- W. Krajewski, A. Lepschy, S. Miani, and U. Viaro, "Frequency-domain approach to robust PI control", J. Franklin Inst., vol. 342, no. 6, pp. 674-687, 2005.
- W. Krajewski and U. Viaro, “On MIMO model reduction by the weighted equation-error approach”, Numerical Algorithms, vol. 44, no. 1, pp. 83-98, 2007.
- W. Krajewski and U. Viaro, "Root-locus invariance", IEEE Control Systems Magazine, vol. 27, no. 1, pp. 36-43, 2007.
- F. Blanchini, S. Miani, M. Tomasini, L. Tubiana, U. Viaro, and M. Zigliotto, "A minimum-time control strategy for torque tracking in permanent magnet ac motor drives", Automatica, vol. 43, no. 3, pp. 505-512, 2007.
- W. Krajewski and U. Viaro, "Locating the equilibrium points of a predator-prey model by means of affine state feedback", J. Franklin Inst., vol. 345, no. 5, pp. 489-498, 2008.
- W. Krajewski and U. Viaro, "Iterative-interpolation algorithms for L2 model reduction", Control and Cybernetics, vol. 38, no. 2, pp. 543-554, 2009.
- F. Blanchini and U. Viaro, "Switched control of fluid networks", Trans. of the Institute of Measurement and Control, vol. 32, no. 6, pp. 582-602, 2010.
- F. Blanchini, D. Casagrande, S. Miani, and U. Viaro, "Stable LPV realization of parametric transfer functions and its application to gain-scheduling control design", IEEE Trans. Automat. Contr., vol. 55, no. 10, pp. 2271-2281, 2010.
- W. Krajewski, S. Miani, A.C. Morassutti, and U. Viaro, "Switching policies for mold level control in continuous casting plants", IEEE Trans. Control Syst. Technol., vol. 19, no. 6, pp. 1493-1503, 2011.
- W. Krajewski and U. Viaro, "A method for the integer-order approximation of fractional-order systems", J. Franklin Inst., vol. 351, no. 1, pp. 555-564, 2014 (doi: 10.1016/j.jfranklin.2013.09.005).
- E. Borgatti and U. Viaro, "A feedback model for the evolution of civilizations", Systems Science & Control Engineering: An Open Access Journal, vol. 2, no. 1, pp. 285-290, 2014.
- F. Blanchini, D. Casagrande, S. Miani, and U. Viaro, "Robust linear parameter-varying control of induction motors", Int. J. Robust and Nonlinear Control, first published online: 28 MAR 2014, DOI: 10.1002/rnc.3174 (2014), vol. 25, no. 12, pp. 1783-1800 2015.
- F. Blanchini, D. Casagrande, S. Miani, and U. Viaro, "Stable LPV realization of the Smith predictor", Int. J. Systems Sci., vol. 47, no. 10, pp. 2393-2401, 2016, first online: 16 February 2015, DOI: 10.1080/00207721.2014.998319.
- W. Krajewski and U. Viaro, "Fractional order PI controllers for TCP packet flow ensuring given modulus margins", Control & Cybernetics, vol. 43, no. 4, pp. 493-505, 2014.
- U. Viaro, "Feedback models of two classical philosophical positions and a semantic problem", Foundations of Science, vol. 21, no. 3, pp. 533-542, 2016, first online: 18 September 2015, DOI 10.1007/s10699-015-9430-2.
- F. Blanchini, D. Casagrande, G. Giordano, and U. Viaro, "A switched system approach to dynamic race modelling", Nonlinear Analysis: Hybrid Systems, vol. 21, pp. 37-48, August 2016, first online: 29 January 2016, DOI:10.1016/j.nahs.2015.12.006 (NAHS Best Paper Award 2017).
- F. Blanchini, D. Casagrande, G. Giordano, and U. Viaro, "Robust constrained Model Predictive Control of fast electromechanical systems", J. Franklin Inst., vol. 353, no. 9, pp. 2087–2103, June 2016, first online: 29 March 2016. DOI: http://dx.doi.org/10.1016/j.jfranklin.2016.03.009.
- D. Casagrande, W. Krajewski, and U. Viaro, "L2-optimal FOPDT models of high-order transfer functions", Asian J. Control, vol. 19, no. 2, pp. 1-10, March 2017, published online in wileyonlinelibrary.com, DOI: 10.1002/asjc.1354.
- D. Casagrande, W. Krajewski, and U. Viaro, "State-response decomposition for model reduction", Systems Science & Control Engineering: An Open Access Journal, vol. 4, no. 1, pp. 379-385, 2016.
- E. Borgatti, D. Casagrande, W. Krajewski, and U. Viaro, "A study of history from a control-theory perspective", Foundations of Science, vol. 23, no. 1, pp. 1-16, March 2018, first online 11 November 2016, DOI: 10.1007/s10699-016-9504-9.
- F. Blanchini, D. Casagrande, G. Giordano, and U. Viaro, "A bounded complementary sensitivity function ensures topology-independent stability of homogeneous dynamical networks", IEEE Trans. Automat. Contr., 2017, first online 9 August 2017, DOI: 10.1109/TAC.2017.2737818.
- D. Casagrande, W. Krajewski, and U. Viaro, "On the asymptotic accuracy of reduced-order models", Int. J. Control Automation and Systems, vol. 15, no. 5, pp. 2436-2442, 2017, first online September 2017, DOI: 10.1007/s12555-015-0443-y.
- W. Krajewski and U. Viaro, "Routh-type L2 model reduction revisited", Kybernetika, vol. 54, 2018.

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Italian journal papers in English

- G. De Poli and U. Viaro, "Design and control of optimal water distribution systems", Ricerche di Automatica, vol. 11, no. 2, pp. 111-131, 1980.
- A. Lepschy, U. Viaro, "Some properties of complete root loci", Alta Frequenza, vol. LII, no. 4, pp. 297-299, 1983.
- A. Lepschy and U. Viaro, "Derivation of root loci from implicit representations", Alta Frequenza, vol. LIII, no. 1, pp. 44-49, 1984.
- A. Lepschy and U. Viaro, "A Padé-like procedure for the Taylor-Chebyshev approximation of rational functions", Alta Frequenza, vol. LIII, no. 3, pp. 181-184, 1984.
- A. Lepschy, G.A. Mian, and U. Viaro, "Frequency-domain approximation of transfer functions using Chebyshev-Padé techniques", Alta Frequenza, vol. LIV, no. 5, pp. 331-341, 1985.
- A. Lepschy, G.A. Mian, and U. Viaro, "Stability of coupled-form digital filters with roundoff quantisation", Alta Frequenza, vol. LVI, no. 8, pp. 357-360, 1987.
- A. Lepschy, G.A. Mian, and U. Viaro, "Contributions to the study of quantization effects in fixed-point digital filters" (invited paper), Alta Frequenza, vol. LVIII, no. 1, pp. 3-14, 1989.
- A. Ferrante, A. Lepschy, and U. Viaro, "Convergence analysis of a fixed-point algorithm", It. J. Pure Appl. Math., no. 9, pp. 179-186, 2001.
- A. Ferrante, A. Lepschy, and U. Viaro, "A variant of a convergent fixed-point algorithm that avoids computing Jacobians", It. J. Pure Appl. Math., no. 10, pp. 47-54, 2001.

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Italian journal papers in Italian

- U. Viaro, "Applicazione delle tecniche di correlazione all'analisi del comportamento dinamico di sistemi lineari", Rivista di Statistica Applicata, vol. 10, no. 1, pp. 25-45, 1977.
- U. Viaro, "Strutture a molti livelli per il controllo di sistemi complessi", Automazione e Strumentazione, vol. XXV, no. 12, pp. 729-733, 1977.
- U. Viaro, "Criteri di studio di un sistema di bonifica idraulica", Rassegna dei Lavori Pubblici, no. 2, pp. 61-73, 1977.
- U. Viaro, "Sull'analisi degli oscillatori non lineari con l'uso delle curve di risposta di fase", Alta Frequenza, vol. XLVII, no. 2, pp. 83-88, 1978.
- F. Brancucci, U. Viaro, "Analisi spettrale della serie temporale del consumo di cemento in Italia negli ultimi quindici anni", L'Industria Italiana del Cemento, Anno XLVII, no. 5, pp. 409-414, 1978.
- F. Brancucci, U. Viaro, "Modello stocastico univariato della serie temporale del consumo di cemento in Italia", L'Industria Italiana del Cemento, Anno XLIX, no. 5, pp. 117-130, 1979.
- F. Brancucci, U. Viaro, "Illustrazione dei modelli Box-Jenkins a funzione di trasferimento con un'applicazione al consumo di cemento in relazione al reddito", L'Industria Italiana del Cemento, Anno XLIX, no. 10, pp. 617-632, 1979.
- G. Milan, U. Viaro, "Ottimizzazione delle reti di distribuzione dell'acqua", Rendic. LXXX Riun. Ann. AEI (tema: Automatica), mem. 4, pp. 1-7, 1979 (1980 AEI-IEL prize).
- R. Caldon, U. Viaro, "Analisi delle curve di carico della rete ENEL nei giorni di punta massima e previsioni a medio termine", Economia delle Fonti di Energia, no. 11, pp. 187-213, 1980.
- R. Caldon, U. Viaro, "Previsione delle curve di massimo carico del sistema elettrico italiano in rapporto ai grandi settori di utenza", L'Energia Elettrica, vol. LVII, no. 12, pp 1-8, 1980.
- R. Caldon, U. Viaro, "Simulazione del carico elettrico di utenze industriali", L'Energia Elettrica, vol. LIX, no. 4, pp. 3-8, 1982.
- A. Lepschy, U. Viaro, "Il problema della costruzione di modelli matematici di ordine ridotto" (with English translation), Scienza e Cultura, no. 5, pp. 133-144, 1983.
- C. Cobelli, A. Lepschy, G. Romanin Jacur, U. Viaro, "L'analisi compartimentale: uno strumento efficace per i problemi di modellizzazione in vari campi applicativi", Ricerca Operativa, no. 36, pp. 69-90, 1985.
- A. Lepschy, U. Viaro, "Alcuni modelli della dinamica del mondo", Pace, Diritti dell'Uomo, Diritti dei Popoli, Anno. II, no. 3, pp. 49-59, 1988.
- A. Ferrante, A. Lepschy, U. Viaro, "Osservazioni su precisione a regime e tipo dei sistemi di controllo", Automazione e Strumentazione, vol. XLVII, no. 2, pp. 125–132, 1999.
- A. Ferrante, A. Lepschy, and U. Viaro, "Sul tracciamento della carta di Nichols della sensibilità", Automazione e Strumentazione, vol. LI, no. 8, pp. 114–116, Settembre 2003.

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Transactions ("Atti") of the Istituto Veneto di Scienze, Lettere ed Arti

- A. Lepschy, G.A. Mian, and U. Viaro, "Computational aspects of rational interpolation", Atti Ist. Veneto SS.LL.AA., Tomo CXLIII: Classe di Scienze Fisiche, Matematiche e Naturali, pp. 67-74, 1985.
- A. Lepschy, G.A. Mian, and U. Viaro, "Limit cycles due to the signal quantization in digital filters", Atti Ist. Veneto SS.LL.AA., Tomo CXLVI: Classe di Scienze Fisiche, Matematiche e Naturali, pp. 1-19, 1988.
- W. Krajewski, A. Lepschy, G.A. Mian, and U. Viaro, "Compact form of the optimality conditions for multivariable L2 model reduction", Atti Ist. Veneto SS.LL.AA., Tomo CL: Classe di Scienze Fisiche, Matematiche e Naturali, pp. 119-128, 1992.
- A. Beghi, A. Lepschy, and U. Viaro, "Recursive evaluation of the squared L2 norm of a rational function", Atti Ist. Veneto SS.LL.AA., Tomo CLI: Classe di Scienze Fisiche, Matematiche e Naturali, pp. 199-208, 1993.
- W. Krajewski, A. Lepschy, and U. Viaro, "Remarks on algorithms for L2 model reduction", Atti Ist. Veneto SS.LL.AA., Tomo CLII: Classe di Scienze Fisiche, Matematiche e Naturali, pp. 99-106, 1994.
- W. Krajewski, A. Lepschy, and U. Viaro, "On the notion of pole dominance", Atti Ist. Veneto SS.LL.AA., Tomo CLIV: Classe di Scienze Fisiche, Matematiche e Naturali, pp. 15-32, 1996.
- A. Lepschy, U. Viaro, "Modelli di influenza reciproca (Mutual causality)", Atti Ist. Veneto SS.LL.AA., Tomo CLIX: Classe di Scienze Fisiche, Matematiche e Naturali, pp. 387-401, 2002.
- A. Lepschy, U. Viaro, "Modelli di civiltà secondo la concezione di Arnold J. Toynbee", Atti Ist. Veneto SS.LL.AA., Tomo CLX: Classe di Scienze Fisiche, Matematiche e Naturali, pp. 249-274, 2003.
- D. Casagrande, U. Viaro, "A mathematical approach to the optimisation of scientific presentations", Atti Ist. Veneto SS.LL.AA., Tomo CLXXV: Classe di Scienze Fisiche, Matematiche e Naturali, 2018 (presented by M.E. Valcher, January 27, 2018).

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Transactions ("Atti") of the Accademia Galileiana (formerly Accademia Patavina)

- A. Lepschy, U. Viaro, "Proprietà di una famiglia di polinomi associati ad una tabella di Routh", Atti Mem. Acc. Patavina SS.LL.AA., vol. XCIV (1981-82), Parte II: Classe di Scienze Matematiche e Naturali, pp. 5-21, 1983.
- A. Lepschy and U. Viaro, "Polynomial truncation and Hurwitz property", Atti Mem. Acc. Patavina SS.LL.AA., vol. XCVIII (1985-86), Parte II: Classe di Scienze Matematiche e Naturali, pp. 23-33, 1987.
- A. Lepschy, G.A. Mian, and U. Viaro, "On the behaviour of certain digital oscillators", Atti Mem. Acc. Patavina SS.LL.AA., vol. C (1987-88), Parte II: Classe di Scienze Matematiche e Naturali, pp. 51-58, 1989.
- A. Lepschy, G.A. Mian, U. Viaro, "Un paradosso a proposito della freccia del tempo", Atti Mem. Acc. Patavina SS.LL.AA., vol. CII (1989-90), Parte II: Classe di Scienze Matematiche e Naturali, pp. 59-69, 1991.
- A. Lepschy, G.A. Mian, U. Viaro, "Da Ctesibio a James Watt: considerazioni in margine allo sviluppo storico dei controlli automatici", Atti Mem. Acc. Patavina SS.LL.AA., vol. CIII (1990-91), Parte II: Classe di Scienze Matematiche e Naturali, pp. 5-16, 1992.
- A. Lepschy and U. Viaro, "Steady-state response revisited", Atti Mem. Acc. Patavina SS.LL.AA., vol. C III (1990-91), Parte II: Classe di Scienze Matematiche e Naturali, pp. 85-94, 1993.
- A. Lepschy and U. Viaro, "Manipulating the Routh table", Atti Mem. Acc. Patavina SS.LL.AA., vol. CV (1992-93), Parte II: Classe di Scienze Matematiche e Naturali, pp. 93-104, 1994.
- A. Ferrante, A. Lepschy, and U. Viaro, "Extension of the concept of system type", Atti Mem. Acc. Patavina SS.LL.AA., vol. CVIII (1995-96), Parte II: Classe di Scienze Matematiche e Naturali, pp. 81-92, 1997.

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Chapters of international research books

- A. Lepschy and U. Viaro, "Some problems in model order reduction using frequency-domain methods", in P.A. Fuhrmann, Ed., Mathematical Theory of Networks and Systems, Lecture Notes in Control and Information Sciences, no. 58, Springer, Berlin, pp. 639-656, 1984.
- C. Cobelli, A. Lepschy, G. Romanin Jacur, and U. Viaro, "Compartmental analysis and its use in management and quantitative economics", in P. Caravani and K. Cichocki, Eds., System Theory and Mathematical Economics, Pitagora Editrice, Bologna, pp. 189-218, 1985.
- A. Lepschy, G.A. Mian, and U. Viaro, "Global asymptotic stability of digital filters with roundoff nonlinearities", in A. Bensoussan and J.L. Lions, Eds., Analysis and Optimization of Systems, Lecture Notes in Control and Information Sciences, no. 83, Springer, Berlin, pp. 617-629, 1986.
- A. Lepschy, G.A. Mian, and U. Viaro, "A four-parameter model with delay for approximating complex distributed systems", in P. Borne and T. Tzafestas, Eds., Applied Modelling and Simulation of Technological Systems, North-Holland, Amsterdam, pp. 153-158, 1987.
- A. Lepschy, G.A. Mian, and U. Viaro, "A comparative analysis of some reduction methods based on quadratic criteria", in P. Breedveld et al., Eds., Modelling and Simulation of Systems, J.C. Baltzer Sci. Publ. Comp., pp. 279-281, 1989 (invited paper).
- A. Lepschy, G.A. Mian, and U. Viaro, "Split forms of z-domain algorithms for linear prediction and stability analysis", in A. Bensoussan and J.L. Lions, Eds., Analysis and Optimization of Systems, Lecture Notes in Control and Information Sciences, no. 144, Springer, Berlin, pp. 218-227, 1990.
- A. Lepschy, G.A. Mian, and U. Viaro, "Split stability-test algorithms: a comparative analysis", in G. Conte, A.M. Perdon and B. Wyman, Eds., New Trends in Systems Theory, Progress in Systems and Control Theory, vol. 7, Birkhauser, Boston, pp. 505-512, 1991.
- A. Lepschy and U. Viaro, "Complexity and feedback", in A. Isidori and T.J. Tarn, Eds., Systems, Models and Feedback: Theory and Applications (in honour of Prof. A. Ruberti), Progress in Systems and Control Theory, vol.12, Birkhauser, Boston, pp. 111-126, 1992.
- A. Lepschy, S. Loro, G.A. Mian, and U. Viaro, "A numerical procedure for rational L2 approximation", in H. Kimura and S. Kodama, Eds., Recent advances in Mathematical Theory of Systems, Control, Networks and Signal Processing, vol. I, Mita Press, Tokyo, pp. 431-436, 1992.
- C. Monti, G.L. Pierobon, and U. Viaro, "Error monitoring characterization in coding systems using finite automata", in H. Kimura and S. Kodama, Eds., Recent advances in Mathematical Theory of Systems, Control, Networks and Signal Processing, vol. II, Mita Press, Tokyo, pp. 55-60, 1992.
- W. Krajewski, A. Lepschy, and U. Viaro, "Second-order information in recursive stability-test algorithms", in U. Helmke, R. Mennicken and J. Saurer, Eds., Systems and Networks: Mathematical Theory and Applications, vol. II, Akademie Verlag, Berlin, pp. 297-300, 1994.
- A. Beghi, A. Lepschy, and U. Viaro, "The Hurwitz matrix and the computation of second-order information indices", in R. Jeltsch and M. Mansour, Eds., Stability Theory, Proc. of the Hurwitz Centenary Conference, International Series of Numerical Mathematics, vol. 121, pp. 1-10, Birkhauser, Boston, 1996.
- A. Ferrante, W. Krajewski, A. Lepschy, and U. Viaro, "An alternative approach to frequency-weighted model reduction", in A. Beghi, L. Finesso and G. Picci, Eds., Mathematical Theory of Network and Systems, Il Poligrafo, Padova, Italy, pp. 153-156, 1998.
- A. Ferrante, A. Lepschy, and U. Viaro, "Forcing convergence of fixed-point algorithms", in A. Beghi, L. Finesso and G. Picci, Eds., Mathematical Theory of Network and Systems, Il Poligrafo, Padova, Italy, pp. 609-612, 1998.
- A. Lepschy and U. Viaro, "Feedback: A technique and a tool for thought”, in M. Lucertini, A. Millan Gasca, and F. Nicolò, Eds., Technological Concepts and Mathematical Models in the Evolution of Modern Engineering Systems, Birkhauser, Basel, pp. 129-155, 2004.
- F. Blanchini, S. Miani, and U. Viaro, "Robust design of standard controllers under plant parameters uncertainty", in G. Picci and M.E. Valcher, Eds., A Tribute to Antonio Lepschy, Edizioni Libreria Progetto, Padova, Italy, pp. 19-29, 2007 (ISBN 9000000000150).
- A. Ferrante, W. Krajewski, and U. Viaro, "The iterative-interpolation approach to L2 model reduction", in G. Picci and M.E. Valcher, Eds., A Tribute to Antonio Lepschy, Edizioni Libreria Progetto, Padova, Italy, pp. 93-103, 2007 (ISBN 9000000000150).
- U. Viaro, "Stability tests revisited", in G. Picci and M.E. Valcher, Eds., A Tribute to Antonio Lepschy, Edizioni Libreria Progetto, Padova, Italy, pp. 189-199, 2007 (ISBN 9000000000150).
- F. Blanchini, D. Casagrande, S. Miani, and U. Viaro, "Parametric gain-scheduling control via LPV-stable realization", in J. Mohammadpour and C.W. Scherer, Eds., Control of Linear Parameter Varying Systems with Applications, Springer, New York, USA, pp. 61-89, 2012 (ISBN 978-1-4614-1832-0).
- W. Krajewski and U. Viaro, "A new method for the integer-order approximation of fractional-order models", in S. Domek and P. Dworak, Eds., Theoretical Developments and Applications of Non-Integer Order Systems, Springer, Cham, Switzerland, pp. 81-92, 2015 (ISBN 978-3-319-23038-2, ISSN 1876-1100).

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Proceedings of international conferences

- S. Stefani and U. Viaro, "On the optimal structure of electric power systems using two-level optimization", Proc. Int. Symp. Advances in Measurement and Control (MECO '78) Athens, June 26-29, pp. 999-1003, 1978.
- S. Stefani and U. Viaro, "A multilevel approach for multiarea power dispatch", Proc. IEEE Control of Power Systems Conf., Texas A&M University, March 19-21, pp. 155-159, 1979.
- A. Lepschy, G. Romanin Jacur, and U. Viaro, "Derivation of the characteristic polynomial of a multivariable system from its signal flow graph", Proc. Int. Symp. Multivariable System Techniques, The Institute of Measurement and Control, Plymouth, 31 Oct. - 2 Nov., pp. 1-8, 1984.
- A. Lepschy, G.A. Mian, and U. Viaro, "Peculiar characteristics of stability regions for a class of digital filters with quantization nonlinearities", Proc. 25th IEEE Control and Decision Conference, Athens, pp. 598-599, 1986.
- W. Krajewski, A. Lepschy, G.A. Mian, and U. Viaro, "General and split forms of some well-known s-domain algorithms", Proc. IEEE Conf. Control and Applications (ICCON '89), April 3-6, Jerusalem, pp. rp-6-6-1 - rp-6-6-3, 1989.
- C.M. Monti, G.L. Pierobon, and U. Viaro, "Observability problems in finite automata as models of coding systems", Proc. Int. Conf. Communication Control Electronics, Cairo, Egypt, pp. 46-50, 1991.
- A. Lepschy, G.A. Mian, and U. Viaro, "Modeling frequency responses by positive rational functions", Proc. IEEE Int. Symp. Circuits Syst., (ISCAS '91), Singapore, June 11-14, pp. 2737-2740, 1991.
- A. Lepschy, G.A. Mian, G. Pinato, and U. Viaro, "Rational L2 approximation: a non-gradient algorithm", Proc. 30th IEEE Control and Decision Conference, Brighton, U.K., pp. 2321-2323, 1991.
- C.M. Monti and U. Viaro, "A Markov-chain model to evaluate the performance of coding systems", Proc. Int. Conf. Communication Control Electronics, Cairo, Egypt, pp. 16-20, 1991.
- E. Lanzotti, A. Lepschy, and U. Viaro, "The root locus approach to the analysis of zero-location procedures", Proc. IEEE Int. Symp. Circuits Syst. (ISCAS '92), San Diego, California, USA, pp. 2398-2401, 1992.
- W. Krajewski, A. Lepschy, and U. Viaro, "A unifying approach to model reduction by preserving first- and second-order information", Proc. 3rd European Control Conf., Rome, vol. 4, pp. 2177-2180, 1995.
- W. Krajewski, A. Lepschy, and U. Viaro, "A comparative analysis of some reduction methods based on first- and second-order information", Proc. IFAC Symp. Large Scale Systems - Theory and Applications, London, vol. 1, pp. 89-92, 1995.
- W. Krajewski, A. Lepschy, and U. Viaro, "An optimization approach to model reduction", Proc. 3rd Int. Conf. Methods and Models in Automation and Robotics, Miedzyzdroje, Poland, pp. 351-356, 1996.
- W. Krajewski, A. Lepschy, and U. Viaro, "Model reduction based on selected measures of the output equation error", Proc. 4th Int. Conf. Advanced Manufacturing Systems and Technology (E. Kuljanic, Ed.), Udine, Italy, CISM Courses and Lectures, no. 372, Springer, Wien, pp. 625-632, 1996.
- A. Ferrante, W. Krajewski, A. Lepschy, and U. Viaro, "Efficient techniques in L2-optimal model reduction", Proc. 4th Int. Conf. Methods and Models in Automation and Robotics, Miedzyzdroje, Poland, pp. 199-204, 1997.
- A. Ferrante, W. Krajewski, A. Lepschy, and U. Viaro, "A new algorithm for L2-optimal model reduction", Proc. 5th Int. Conf. Methods and Models in Automation and Robotics, Miedzyzdroje, Poland, pp. 213-218, 1998.
- F. Blanchini, F. Miani, S. Miani, and U. Viaro, "Robust PID controller tuning for continuous casting mold level control", Proc. 5th Int. Conf. Advanced Manufacturing Systems and Technology (E. Kuljanic, Ed.), Udine, Italy, CISM Courses and Lectures, no. 406, Springer, Wien, pp. 635-642, 1999.
- A. Ferrante, W. Krajewski, A. Lepschy, and U. Viaro, "A convergent algorithm for L2-optimal MIMO model reduction", Proc. 5th Int. Conf. Advanced Manufacturing Systems and Technology (E. Kuljanic, Ed.), Udine, Italy, CISM Courses and Lectures, no. 406, Springer, Wien, pp. 651-657, 1999.
- F. Blanchini, V. Francesconi, S. Miani, and U. Viaro, "Molten steel level control", Proc. 14th Int. Symp. Mathematical Theory of Networks and Systems, Perpignan, France, CD ROM, 2000.
- A. Ferrante, W. Krajewski, A. Lepschy, and U. Viaro, "A family of nongradient algorithms for L2-optimal MIMO model reduction", Proc. 6th Int. Conf. Methods and Models in Automation and Robotics, Miedzyzdroje, Poland, pp. 284-289, 2000.
- A. Ferrante, W. Krajewski, A. Lepschy, and U. Viaro, "A simple procedure for analytic stability margin design", Proc. 7th IEEE Int. Conf. Methods and Models in Automation and Robotics, Miedzyzdroje, Poland, pp. 309-314, 2001.
- A. Ferrante, W. Krajewski, A. Lepschy, and U. Viaro, "Robustness with respect to phase variation: a design criterion", Proc. 8th IEEE Int. Conf. Methods and Models in Automation and Robotics, Miedzyzdroje, Poland, pp. 433-438, 2002.
- A. Beghi, W. Krajewski, A. Lepschy, and U. Viaro, "Remarks on delay approximations based on feedback", Proc. 4th Int. Conf. Algorithms for Approximation, Huddersfield, UK, pp. 412-419, 2002.
- W. Krajewski, A. Lepschy, S. Miani, and U. Viaro, "Robustness analysis of frequency-domain PI controller design procedures", Proc. 6th Conf. Advanced Manufacturing Systems and Technology (E. Kuljanic, Ed.), Udine, Italy, CISM Courses and Lectures, no. 437, Springer, Wien, pp. 585-592. 2002.
- F. Blanchini, A. Lepschy, S. Miani, and U. Viaro, "Characterization of standard controllers satisfying given H-infinity specifications", Proc. 42nd IEEE Control and Decision Conference, Maui, HI, USA, pp. 6474–6479, 2003.
- W. Krajewski, A. Lepschy, and U. Viaro, "PI controllers for robust stability and performance", Proc. 9th IEEE Int. Conf. Methods and Models in Automation and Robotics, Miedzyzdroje, Poland, pp. 224-229, 2003.
- W. Krajewski, A. Lepschy, and U. Viaro, "On MIMO model reduction by the equation error approach", Proc. 10th IEEE Int. Conf. Methods and Models in Automation and Robotics, Miedzyzdroje, Poland, pp. 291-296, 2004.
- A. Ferrante, W. Krajewski, A. Lepschy, S. Miani, and U. Viaro, "Simultaneous stabilization of multiple equilibrium points", Proc. 43rd IEEE Control and Decision Conference, Atlantis, Paradise Island, Bahamas, USA, pp. 2533-2536, 2004.
- A. Ferrante. W. Krajewski, A. Lepschy, and U. Viaro, "L2 model reduction - Nongradient approach", Proc. 15th Int. Conf. Systems Science, Wroclaw, Poland, pp. 263-270, 2004.
- W. Krajewski, A. Lepschy, and U. Viaro, "Equilibria and stability of predator-prey models", Proc. 11th IEEE Int. Conf. Methods and Models in Automation and Robotics, Miedzyzdroje, Poland, pp. 227-231, 2005.
- F. Blanchini, S. Miani, M. Tomasini, L. Tubiana, U. Viaro, and M. Zigliotto, "A minimum-time control strategy for torque tracking in permanent magnet AC motor drives", Proc. 16th IFAC World Congress, Praga, Czech Republic, CD ROM, 2005.
- F. Blanchini, A. Lepschy, S. Miani, and U. Viaro, "Constrained H-infinity design of PID controllers", Proc. 7th Int. Conf. Advanced Manufacturing Systems and Technology (E. Kuljanic, Ed.), Udine, Italy, CISM Courses and Lectures, no. 486, Springer, Wien, pp. 297-305, 2005.
- W. Krajewski and U. Viaro, "On the equation-error approach to MIMO model reduction", Proc. 12th IEEE Int. Conf. Methods and Models in Automation and Robotics, Miedzyzdroje, Poland, pp. 847-852, 2006.
- W. Krajewski and U. Viaro, "Iterative-interpolation algorithms for L2 model reduction", Proc. 13th IEEE-IFAC Int. Conf. Methods and Models in Automation and Robotics, Szczecin, Poland, pp. 135-140, 2007.
- W. Krajewski and U. Viaro, "On model reduction based on weighted equation errors", Proc. 11th IFAC-IFORS-IMACS-IFIP Symp. Large Scale Systems - Theory and Applications, Gdansk, Poland, CD ROM, pp. 1-6, 2007.
- W. Krajewski, S. Miani, A.C. Morassutti, and U. Viaro, "Multicontroller design for continuous casting mold level control", Proc. 8th Int. Conf. Advanced Manufacturing Systems and Technology (E. Kuljanic, Ed.), Udine, Italy, pp. 653-663, 2008.
- F. Blanchini, W. Krajewski, S. Miani, and U. Viaro, "A sliding mode strategy to control TCP flows", Proc. 14th IEEE-IFAC Int. Conf. Methods and Models in Automation and Robotics, Miedzyzdroje, Poland, CD ROM (paper F-154), pp. 1-5, 19-21 August 2009.
- F. Blanchini, W. Krajewski, S. Miani, and U. Viaro, "Robust TCP packets queue control", Proc. 1st IFAC Workshop on Estimation and Control of Networked Systems, Venice, Italy, CD ROM (paper FrBT1.17), pp. 293-297, 24-26 September 2009.
- F. Blanchini, D. Casagrande, S. Miani, and U. Viaro, "Stable LPV realization of parametric transfer functions and its application to gain-scheduling control design", Proc. Joint 48th IEEE Conf. Decision and Control and 28th Chinese Control Conf., Shanghai, China, CD ROM (paper FrB03.6), pp. 7436-7441, 16-18 December 2009.
- W. Krajewski, S. Miani, and U. Viaro, "Variable-structure control of casting processes", Proc. 15th IEEE-IFAC Int. Conf. Methods and Models in Automation and Robotics, Szczecin, Poland, pp. 49-54, 23-26 August 2010 (paper ID 9010).
- F. Blanchini, D. Casagrande, W. Krajewski, S. Miani, and U. Viaro, "Stable point-wise optimal LPV control of induction motors", Proc. 9th Int. Conf. Advanced Manufacturing Systems and Technology (E. Kuljanic, Ed.), Mali Losinj, Croatia, pp. 261-269, 16-17 June 2011.
- W. Krajewski and U. Viaro, "On the rational approximation of fractional-order systems", Proc. 16th IEEE Int. Conf. Methods and Models in Automation and Robotics, Miedzyzdroje, Poland, pp. 132-136, 22-25 August 2011 (paper ID A5L-B1).
- W. Krajewski and U. Viaro, "On robust PID control for time-delay plants", Proc. 17th IEEE Int. Conf. Methods and Models in Automation and Robotics, Miedzyzdroje, Poland, pp. 540-545, 27-30 August 2012 (paper ID 1005 - C2L-A).
- F. Blanchini, D. Casagrande, S. Miani, and U. Viaro, "An LPV control scheme for induction motors", Proc. 51st IEEE Conf. Decision and Control, Maui, Hawaii, USA, CD ROM, pp. 7602-7607, 10-13 December 2012 (paper ThC12.2).
- W. Krajewski and U. Viaro, "On robust PI-lambda D-mu control for time-delay non-integer order plants", Proc. 18th IEEE Int. Conf. Methods and Models in Automation and Robotics, Miedzyzdroje, Poland, pp. 616-621, 26-29 August 2013.
- D. Casagrande, W. Krajewski, and U. Viaro, "LPV embedding of nonlinear compartmental systems with endogenous control", Proc. 19th IEEE Int. Conf. Methods and Models in Automation and Robotics, Miedzyzdroje, Poland, pp. 891-896, 2-5 September 2014.
- W. Krajewski and U. Viaro, "On robust fractional order PI controllers for TCP packet flow", Proc. 13th BOS Conf.: Systems and Operational Research, Warsaw, Poland, 24-26 September 2014 (paper FrBOSVII-2).
- F. Blanchini, D. Casagrande, G. Giordano, and U. Viaro, "Properties of switching-dynamics race models", Proc. 14th European Control Conference, Linz, Austria, pp. 2902-2907, 15-17 July 2015.
- D. Casagrande, W. Krajewski, and U. Viaro, "A feedback model of evolutionary adaptation", Proc. 20th IEEE Int. Conf. Methods and Models in Automation and Robotics, Miedzyzdroje, Poland, pp. 412-417, 24-27 August 2015 (paper ID 7022).
- D. Casagrande, W. Krajewski, and U. Viaro, "Adapting state-space reduction techniques to match steady-state responses", Proc. 21th IEEE Int. Conf. Methods and Models in Automation and Robotics, Miedzyzdroje, Poland, pp. 1234-1239, 29 August - 1 September 2016 (paper ID 6009).
- F. Blanchini, D. Casagrande, G. Giordano, and U. Viaro, "Topology-independent robust stability of homogeneous dynamic networks", Proc. IFAC World Conf., Toulouse, France, pp. 1772-1777, 9-14 July 2017 (paper MoM12.1).
- F. Blanchini, D. Casagrande, W. Krajewski, and U. Viaro, "A method for the order reduction of linear switching systems", Proc. 21th IEEE Int. Conf. Methods and Models in Automation and Robotics, Miedzyzdroje, Poland, 28-31 August 2017 (paper ID 6002).

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Books and papers on education and cultural issues

- U. Viaro, Analisi delle Serie Temporali, Ind. Grafiche Cattaneo, Bergamo, 1977, pp. 80.
- U. Viaro, Introduction to Statistical Hydrology - Part 1, Int. Centre of Hydrology, Univ. Padova, no. 21, 1981, pp. 92.
- U. Viaro, Introduction to Statistical Hydrology - Part 2: Common Probability Distributions, Model Contruction, Int. Centre of Hydrology, Univ. Padova, no. 22, 1981, pp. 65.
- A. Lepschy, U. Viaro, Guida allo Studio dei Controlli Automatici, Pàtron Editore, Bologna, 1983, pp. IX+372 (2^ edizione: Pàtron Editore, Bologna, 1986).
- A. Lepschy, G. Romanin Jacur, U. Viaro, L'Informatica e la Telematica nella Bonifica e nell'Irrigazione, Nuovi Orientamenti nel Campo della Bonifica e dell'Irrigazione, CUOA, Altavilla (Vicenza), 1983, pp. 35.
- U. Viaro, "Caratteristiche, prospettive, requisiti degli studi in ingegneria" [Requirements of engineering studies], in E. Cristofoletti, L. Bussadori, Eds., Prospettive Formative dopo la Maturità, Prov. Autonoma di Bolzano, Assessorato all'Istruzione e Cultura, La Commerciale-Borgogno, Bolzano, pp. 115-131, 1991.
- A. Lepschy, G.A. Mian, U. Viaro, "La retroazione (feedback) e le sue proprietà", Nuova Secondaria, Anno 8, no. 2, pp. 23-32, 49-54, 59-62, 62-64, 1991.
- A. Lepschy, U. Viaro, "L'alba della complessità", Nuova Civiltà delle Macchine, vol. XI, no. 3-4, pp. 58-68, 1993.
- A. Lepschy, U. Viaro, "Galileo e la misura dello spazio e del tempo", Atti Celebrazioni Galileiane 1592-1992, vol. V, pp. 109-128, LINT, Trieste, 1995.
- E. Borgatti, U. Viaro, Esercizi Elementari di Controlli Automatici, Pàtron Editore, Bologna, 1998, pp. I+257 (2^ edizione: Pàtron Editore, Bologna, 2003, pp. III+299).
- A. Ferrante, A. Lepschy, U. Viaro, Introduzione ai Controlli Automatici, UTET, Torino, 2000, pp. XVI+522 (1^ ristampa: De Agostini Scuola, Novara, 2008).

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Books on research

- U. Viaro, Twenty-Five Years of Research with Antonio Lepschy, Edizioni Libreria Progetto, Padova, Italy, 2009, pp. 123.
- U. Viaro (preface by W. Krajewski), Essays on Stability Analysis and Model Reduction, Polish Academy of Sciences, Warsaw, Poland, 2010, pp. XII+122.

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Project and laboratory reports

- A. Adami, U. Viaro, "Dimensionamento in modello della strozzatura alla base del pozzo piezometrico della Centrale di S. Fiorano (ENEL Compartimento di Venezia)" [Surge tank's restricted orifice design and experimental test], Ricerca P/195, Istituto di Idraulica, Univ. Padova, 1979.
- A. Adami, U. Viaro, "Progetto ed esame su modello della strozzatura del pozzo piezometrico della Centrale di Avio-Edolo (ENEL Compartimento di Venezia)" [Surge tank's opening design and experimental test], Ricerca P/197, Istituto di Idraulica, Univ. Padova, 1980.
- A. Lepschy, U. Viaro, "Alcuni problemi relativi alla costruzione di modelli di ordine ridotto" [Problems in reduced-order modelling], in E. Mosca, Ed., Metodologie e Dispositivi per l'Identificazione, il Controllo e l'Elaborazione di Segnali nei Sistemi Dinamici, Tecnoprint, Bologna, pp. 99-103, 1985.
- A. Lepschy, G. Romanin Jacur, U. Viaro, "Manipolazioni di grafi orientati" [Manipulation of directed graphs], in E. Mosca, Ed., Metodologie e Dispositivi per l'Identificazione, il Controllo e l'Elaborazione di Segnali nei Sistemi Dinamici, Tecnoprint, Bologna, pp. 155-159, 1986.
- C. Cobelli, A. Lepschy, G. Romanin Jacur, U. Viaro, "Sistemi compartimentali con controllo" [Compartmental systems with control], in E. Mosca, Ed., Metodologie e Dispositivi per l'Identificazione, il Controllo e l'Elaborazione di Segnali nei Sistemi Dinamici, Tecnoprint, Bologna, pp. 59-62, 1987.
- A. Lepschy, U. Viaro, "Problemi di modellistica e di elaborazione di segnali digitali" [Digital system modelling problems], in E. Mosca, Ed., Metodologie e Dispositivi per l'Identificazione, il Controllo e l'Elaborazione di Segnali nei Sistemi Dinamici, Tecnoprint, Bologna, pp. 93-97, 1988.
- A. Lepschy, G.A. Mian, U. Viaro, "Metodi ricorsivi per la semplificazione ottima di modelli lineari" [Recursive methods for optimal model reduction], in S. Bittanti, Ed., Identificazione di Modelli, Controllo di Sistemi, Elaborazione di Segnali, Tecnoprint, Bologna, pp. 29-34, 1989.
- A. Beghi, A. Ferrante, A. Lepschy, U. Viaro, "Problemi di approssimazione e semplificazione di modelli" [Model approximation issues], in G. Picci, Ed., Identificazione di Modelli, Controllo di Sistemi, Elaborazione di Segnali, Progetto Nazionale MURST, Libreria Progetto, Padova, pp. 64-71, 1996.
- U. Viaro, Relazione scientifica del progetto "Applicazione di tecniche di controllo innovative per servomeccanismi ed azionamenti in campo industriale e civile", cofinanziato con L.R. 3/98 - bando 2002, Dipartimento di Ingegneria Elettrica, Gestionale e Meccanica, Università degli Studi di Udine, 2003.

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