- Andrzej Czyżewski, Prof., DSc, Eng. - Full Professor, Head of the Department
- Bożena Kostek, Prof., DSc, Eng. - Full Professor, Head of the Audio Acoustics Laboratory
- Józef Kotus, DSc, Eng. - Professor
- Mariusz Mróz, DSc - Professor
- Piotr Odya, PhD, Eng. - Assistant Professor, Head of Department Labs
- Arkadiusz Harasimiuk, PhD, Eng. - Assistant Professor
- Michał Kucewicz, PhD - Brain and Mind Electrophysiology Laboratory
- Michał Lech, PhD, Eng. - Assistant Professor, Brain and Mind Electrophysiology Laboratory
- Karolina Marciniuk, PhD, Eng. - Assistant Professor
- Piotr Szczuko, PhD, Eng. - Assistant Professor
- Grzegorz Szwoch, PhD, Eng. - Assistant Professor
- Daniel Węsierski, Ph.D, Eng. - Assistant Professor
- Piotr Sokołowski, MSc, Eng. - Assistant
- Paweł Spaleniak, MSc, Eng. - Assistant
- Szymon Zaporowski, MSc, Eng. - Assistant
- Maciej Blaszke, MSc, Eng.
- Sebastian Cygert, MSc, Eng.
- Aleksandra Dorochowicz, MSc, Eng.
- Damian Koszewski, MSc, Eng.
- Adam Kurowski, MSc, Eng.
- Karol Lisowski, MSc, Eng.
- Bartłomiej Mróz, MSc, Eng.
- Marta Stefaniak, MSc, Eng.
- Dawid Weber, MSc, Eng.
Participants in scientific projects
- Piotr Hoffmann, PhD, Eng. - Project Manager
- Maciej Szczodrak, PhD, Eng. - Specialist
- Olga Szmit, MSc., Eng. - Specialist
Andrzej Czyżewski, Prof., DSc, Eng.
Head of the Multimedia Systems Department
Professor dr hab. Eng. Andrzej Czyżewski defended his doctoral thesis with distinction on the subject of digital sound at the Faculty of Electronics of Gdańsk University of Technology in 1987. In 1992 he presented his habilitation thesis, then in 1999 received the title of professor from the President of the Republic of Poland. In 2003, the Minister of Education appointed him a full professor at the Gdańsk University of Technology. From 1991 he managed the research and didactic department at the Gdańsk University of Technology, which in 1997 was transformed into the Department of Sound Engineering, and in 2003 into the Department of Multimedia Systems. Since 2000, he has been awarded the Fellow title by the international scientific society, namely the Audio Engineering Society.
His scientific interests focus on topics related to multimedia techniques and their numerous interdisciplinary applications, including in audiology, speech therapy and otolaryngology, neurology, biometrics, computerization of roads, telemonitoring of the environment and infrastructure. To date, he has managed over 30 national projects and 7 EU projects (in the scope of PG tasks). The inventions and implementations that he created in the team he managed received many prestigious national and foreign awards, including in 2007 he received the Scientific Award of the City of Gdańsk Jan Heweliusz, considered the highest distinction for the scientist of the Gdańsk Land. He is the winner of the awards of the Minister of Science and Higher Education and twice the First Prize of the Prime Minister for research and implementation achievements (2000 and 2014). He was awarded the Knight's Cross of the Order of Rebirth of Poland, in 2018 the Officer's Cross of the Order of Rebirth of Poland, as well as the Knight's Cross of the European Order of Invention. In 2015, the invention of "CyberEye" developed under his guidance was awarded the "Teraz Polska" promotional emblem and was awarded the prestigious international Prix Galien award. In 2018, Gdańsk entrepreneurs honored him with the "Primum Cooperatio" award, while the Mayor of Gdańsk awarded the Medal of the 100th Anniversary of Independence.
He heads the Gdańsk University of Technology specializing in engineering: "Multimedia technologies" and MSc.: "Sound and image engineering". He cooperates with, among others with the Institute of Physiology and Pathology of Hearing, with the Medical University of Gdańsk and with corporations such as Intel and Samsung, with the PKO BP Bank, with the General Directorate of National Roads and Mororways and with many smaller enterprises in which he implements inventions and innovations being developed. He is the author of over 600 scientific publications (including 3 monographs) and nearly 30 patents. He has so far promoted 13 doctors and over 300 masters of science and engineers.
Bożena Kostek, Prof., DSc, Eng.
Head of the Audio Acoustics Laboratory
Józef Kotus, DSc, Eng.
Józef Kotus graduated from the Faculty of Electronics Telecommunications and Informatics, Gdansk University of Technology in 2001. In 2008 he completed his PhD under the supervision of prof. Bożena Kostek. His PhD work concerned issues connected with application of information technology to the noise monitoring and prevention of the noise-induced hearing loss. He is a member of the Audio Engineering Society (AES) and European Acoustics Association (EAA). He is an author and co-author of more than 110 scientific publications, including 13 articles from the ISI Master Journal List and 27 articles in the reviewed papers. Also four chapters co-authored by him were published by Springer. He has an extensive experience in sound and image processing algorithms and noise measurements and noise control techniques as well. Moreover, he participated in many national and European research projects.
Mariusz Mróz, DSc
Mariusz Mróz – conductor of the Academic Choir of Gdańsk University of Technology. He is the organizer of musical life at the Gdańsk University of Technology (symphonic concerts, chamber music, nationwide and international choral festivals). In the years 2000-2012 he was the president of the Gdańsk branch of the Polish Association of Choirs and Orchestras (Polski Związek Chórów i Orkiestr – PZCHiO), and also he was a member of the PZCHiO General Board in Warsaw. He is a laureate of the Nationwide Competition of Conductors in Poznań (1990), and participant in the Master Conducting Course in Bruges (Belgium 1991). He also realizes himself (performs?) as a pedagogue and symphonic conductor, by conducting the orchestra of Secondary Music School in Gdańsk. He gave concerts on many domestic and foreign stages (Belgium, Germany, France, Spain, Mexico, Denmark, Sweden, Estonia, Lithuania, Russia, Czech Republic, Austria, Slovenia, Italy, the Netherlands, Hungary, Macedonia).
Artistic and scientific interests: orthodox church music, baroque music, contemporary music and music sociology.
Among the innumerable concerts one can mention oratorio concerts with music by Bach, Mozart, Beethoven, Rossini, Ramirez, Kilar, Szymanowski, Orff and Nowowiejski.
Examples of titles of oratorial works:
- Johann Sebastian Bach: Magnificat
- Ludwig van Beethoven: Symphony No. 9
- Wojciech Kilar: Missa Pro Pace
- Franz Liszt: Christus
- Wolfgang Amadeus Mozart: Davide Penitente
- Wolfgang Amadeus Mozart: Requiem in D minor
- Carl Orff: Carmina Burana
- Ariel Ramírez: Misa Criolla
- Karol Szymanowski: Stabat Mater
He has prepared over 110 oratorio concerts with the Academic Choir of the Gdańsk University of Technology, including 65 concerts conducted personally as a conductor.
He took part in 32 national and 22 international choir competitions and festivals where he received a total of 55 awards and distinctions (3 Grand Prix, 3 prizes for the best conductor of the festival, 11 first places, 13 gold diplomas).
He prepared theatrical and operatic performances, including:
- J. K. Pawluśkiewicz: „Nieszpory Ludźmierskie”, reżyseria Robert Gliński
- J. Bock: „Fiddler on the Roof”, direction: J. Gruza, J. Szurmiej
- C. M. Schönberg: „Les Misérables”, direction: J. Gruza
- L. Bernstein: „West Side Story”, direction: T. Dutkiewicz
- P. Tchaikovsky: „Eugene Onegin”
- C. W. Gluck: „Orfeo ed Euridice”
He was honoured for his artistic and didactic achievements:
- PZCHiO honour badge – gold with laurel wreath
- Award of the Mayor of the City of Gdańsk – for merits in the field of culture
- Medal of the Mayor of the City of Gdańsk
- Award of the Director of the Music School – for achievements in didactic and educational work on the occasion of the National Education Day (annually)
- Bronze Medal of the jubilee of the 800th anniversary of Żukowo –for creating and organizing a choir festival in Żukowo, which continues to this day
- Medal for merit for the Gdańsk University of Technology
- Hevelius' Medal – Gdańsk University of Technology
He is the author of many publications on orthodox music, a speaker at scientific conferences, a juror at national and international choral competitions, among others is a juror at the International Festival of Children and Young Choirs “Rainbow” – St. Petersburg (Russia).
Piotr Odya, PhD, Eng.
Piotr Odya was born in Gdansk in 1974. He received his MSc. in 1999 from the Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology, Poland. His thesis was related to the problem of sound quality improvement in the contemporary broadcasting studio. He is interested in video editing and multichannel sound systems. The goal of Mr. Odya PhD thesis concerned methods and algorithms for correcting stuttering. In 2007 Piotr Odya received his PhD At present, he works at the Multimedia Systems Department as an Assistant professor.
His research focuses on audio signals processing, auditory-visual signals perception and telemedicine. He is also interested in video compression algorithms and multichannel sound systems. Piotr Odya is an author and co-author of over 70 papers.
From 2007 to 2009 he coordinated a project called "MULTIMODAL". From 2009 to 2014 Piotr Odya coordinated a project called "TYPOSZEREG". The aim of these two project was to develop new kinds of multimodal interfaces.
From 1999 to 2001 Piotr Odya was the chairman of the AES Polish Student Section. From 2001 to 2005 he was the treasurer of the AES PSS.
Piotr Odya is the webmaster of the Multimedia Systems Department website (including Telewelfare portal).
Arkadiusz Harasimiuk, PhD, Eng.
Arkadiusz Harasimiuk graduated from Maritime Electronics at the Faculty of Electrical Engineering of the Maritime University (currently Maritime University) in 1992, earning the title of Master of Science in Engineering. In 2013, he defended his doctoral dissertation at the University of Gdańsk. His dissertation concerned reference models for SOA and BPM applications in financial services. He has over 20 years of experience in implementing IT projects in the area of telecommunications and banking. In 2020, he joined the team responsible for the implementation of the BIOPUAP project at the Multimedia Systems Department.
His interests include IoT solutions in both industrial solutions, smart home and smart city, the use of IoT data for data analysis. He is also interested in sound and video systems. In his free time he is interested in motorization, diving and music.
Michał Kucewicz, PhD
Brain and Mind Electrophysiology Laboratory
Michal Kucewicz was born in 1986 in Gdansk. In 2005 he completed International Baccalaureate programme in Topolowka (III High School in Gdańsk). Thanks to the G. D. Fahrenheit scholarship, he moved to the United Kingdom to study neuroscience. He received his Bacholer's and Master's degree from the Cambridge University, and his doctoral degree from the University of Bristol specializing in electrophysiology of memory and cognitive functions of the brain. His doctoral thesis described weas focused on the mechanisms of working memory as studied on the level of electrical activity of neuronal networks. Following the doctoral studies he continued the research on memory at Mayo Clinic in the USA working with invasive recordings in epilepsy patients. His projects develop technology for electrical stimulation of the brain for memory enhancement in patients suffering from epilepsy, Parkinson's disease and other neurodegenerative disorders. The goal of his research is to discover the mechanisms of human memory and mind.
The passion of his life is evangelization.
Michał Lech, PhD, Eng.
Michał Lech was born in Gdynia in 1983. In 2007 he graduated from the faculty of Electronics, Telecommunications and Informatics, specialization: Distributed Applications and Internet Systems in the Computer Architecture Department. The subject of his thesis was the application for automatic pitch detection and correction of detuned singing. In June 2013, he received his PhD degree. The subject of the dissertation was: "The method and algorithms for controlling sound mixing processes by hand gestures using video image analysis".
He is interested in image processing and artificial intelligence algorithms. In the scope of the research projects he develops multimodal interfaces utilizing C++ and JAVA languages.
His non-scientific interests concern guitar playing, music production, and symphonic orchestration.
Karolina Marciniuk, PhD, Eng.
Karolina Marciniuk was born in Wejherowo in 1988. In 2013 she graduated from the Faculty of Electronics, Telecommunications and Informatics of the Gdańsk University of Technology. The subject of her MSc. Eng. thesis was related to the dynamic noise map of the selected area of the city of Gdansk. In 2019, she completed her doctoral dissertation on the acoustic analysis of road traffic. Her research interests are focused on room acoustics, signal processing and video production.
Between 2016 and 2018 she worked in the INPREDO project. Currently, she is a supervisor of the Sound and Image Engineering Student Chapter and works in the INZNAK project.
In her free time she takes photos, run or sail.
Piotr Szczuko, PhD, Eng.
Piotr Szczuko received his MSc. degree in 2002. His thesis was dedicated to examination of correlation phenomena between perception of sound and vision for surround sound and digital image. He finished PhD studies in 2007 and one year later completed a dissertation "Application of Fuzzy Rules in Computer Character Animation" that received award of Prime Minister of Poland.
His interests include processing of audio and video, computer animation, 3D visualization, inference methods, artificial intelligence, applications of rough sets theory, classification and perception of sound and image, algorithms and methods of image analysis and understanding, applications of embedded systems.
Since 2007 he is main specialist in domestic and international research and development projects (INDECT, ADDPRIV, COPCAMS), devoted to audio and video processing for automatic detection of threats by intelligent surveillance systems.
He is an author and co-author of over 80 papers, book chapters, and articles, and co-author of awarded innovative solutions "Electronic Aids for Laryngectomees", and “Remote acoustic and visual observation system".
P. Szczuko prepares and lectures courses of "Intelligent Decision Systems", "Artificial Intelligence in Medicine", "Sound and Image Processing", "Telemonitoring of Objects and Agglomerations" and "Audio Forensics and Image Analysis" and supervising Bachelors and Masters thesis and student projects.
Grzegorz Szwoch, PhD, Eng.
Grzegorz Szwoch was born in 1972 in Gdansk. In 1991-1996 he studied at the Technical University of Gdansk. In 1996 he graduated as a student from the Sound Engineering Department. His thesis was related to physical modeling of musical instruments. Since that time he has been a member of the research staff at the Multimedia Systems Department as a PhD student (1996-2001), assistant (2001-2004) and Assistant professor (since 2004). The subject of his PhD thesis was computer modeling of the hearing aid acoustic system.
The main subject of his research is automated video analysis and event detection in video surveillance systems. He participated and still participates in several scientific projects (European and Polish) on this subject. His main scientific interests include programming (C++ and scripting languages), video analysis and processing, sound synthesis, 3D computer graphics and computer technologies in general. His personal interests are: music, computer games, programming and public transport.
Grzegorz Szwoch is the author and the lecturer of courses on Electronic musical instruments, Image synthesis and Studio measurements. He is also an administrator of the department's server and computer network, and also of this web page.
Daniel Węsierski, Ph.D, Eng.
Daniel Węsierski received his MSc. in Automation and Robotics in 2007 from the Gdansk University of Technology. He gained corporate experience in R&D departments of ThyssenKrupp in Bremen and of Volkswagen in Wolfsburg in 2005-2009. He received his PhD in Computer Science from Telecom SudParis in 2013 under the supervision of Patrick Horain.
His interests lie in computer vision, with emphasis on visual object tracking.
Piotr Sokołowski, MSc., Eng.
Piotr Sokołowski was born in Gdańsk in 1994. In 2018 he graduated from Gdańsk University of Technology, Faculty of Electronics, Telecommunications acquiring MSc. degree. The subject of engineer's thesis was developing functionality of exFAT file system and the subject of his master thesis was improving methods of saving space in file systems. He gained corporate experience as smart card operating system developer in National Institute of Telecomunication. He is interested in improving performance of processing, storing and transmission various multimedia data like in particular music. Moreover, outside academic work, he is interested in building paper models, history, literature, sport, singing and playing piano.
Paweł Spaleniak, MSc, Eng.
Paweł Spaleniak was born in 1987 in Gdynia. In 2011 he graduated from Gdańsk University of Technology, Faculty of Electronics, Telecommunications and Informatics in the Multimedia Systems Department, obtaining a master's degree in engineering. The aim of his thesis develop software capable to automatically analyze the level of emitted commercials.
His interests include audio and image analysis and processing using C++ language. He is a graphic designer, mainly for web applications. Moreover, he is interested in room acoustics, as well as audio recording, mixing and mastering.
Szymon Zaporowski, MSc., Eng.
Szymon Zaporowski was born in Gdańsk in 1992. In 2017 he received MSc degree in Electronics and Telecommunication form Gdańsk University of Technology, specialization Sound and Vision Engineering. His B.Sc thesis was about creating Guitar effects processor for Android devices. Subject of MSc thesis was creating waveguide VST string synthesizer. In 2017 he receive silver medal award in Student Design Competition at 142nd AES convention in Berlin for System for rapid prototyping of acoustic diffusers.
His scientific interests include issues connected with speech processing, machine learning, digital sound synthesis, image processing and different fields of acoustics.
His other interests are music, playing on the instruments, literature and history, especially history of Gdańsk city.
Maciej Blaszke, MSc., Eng.PhD Student
Maciej Blaszke was born in Wejherowo in 1993. In 2017 he graduated from Gdańsk University of Technology, Faculty of Electronics, Telecommunications and Informatics in the Multimedia Systems Department, obtaining a master's degree in engineering. His MSc thesis was detection of audio events in the audio recordings of the road traffic. The aim of his B.Sc thesis develop guitar processor for Android devices. In 2017 at the AES convention in Berlin he received silver award in Student Design Competition for System for rapid prototyping of acoustic diffusers.
His interests include signal processing, live video and audio events, machine learning and acoustics. Additionally his hobbies are RC models, automotive and modern technologies.
Sebastian Cygert, MSc., Eng.
Sebastian Cygert was born in Gdansk, 1989. He recevied engireeing degree from Warsaw Military Universtity of Technology, in cryptology. MSc. degree was received from Warsaw Universtity of Technology, on Faculty of Mathematics and Computer Science. The thesis subject was Usage of GPUs in computer simulation of heavy ion nuclei. He gained corporate experience as software developer in Samsung, Warsaw and in RiskFirst, London working on financial models. He is interested in artificial intelligence, traveling, music and sport.
Aleksandra Dorochowicz, MSc., Eng.
Aleksandra Dorochowicz was born in 1992 in Gdańsk. She graduated the master studies from the Multimedia Systems Department at the faculty of Electronics, Telecommunications and Informatics at Gdansk University of Technology in 2016. The Engineer's Thesis was based on the conducting listening tests aimed at recognizing timbre of musical instruments, and the Master's Thesis - conducting subjective listening tests of an audio graphic equalizer with automatic music genre recognition. She is interested in graphics and music issues. Among the other interests can be mentioned history, literature, philology, genetics and sport.
Damian Koszewski, MSc., Eng.
Damian Koszewski was born on 1991 in Gdansk. In 2017 he graduated from the Faculty of Electronics, Telecommunications and Informatics at Gdansk University of Technology acquiring MSc. degree. The subject of his M.S. Thesis was associated with subjective tests aimed at the assessment of sound similarity of the virtual and real musical instruments.
His scientific interests concern sound and video processing and perception. His other interests include production and composition of music and playing of instruments.
Adam Kurowski, MSc., Eng.
Adam Kurowski was born in 1991 in Gdansk. In 2015 he graduated with honors from the Faculty of Electronics, Telecommunications and Informatics at Gdansk University of Technology acquiring MSc. degree. The subject of his B.Sc thesis was implementation and evaluation of performance of a virtual bass synthesis algorithm for small electroacoustic transducers. His MSc. Thesis was associated with sound intensity measurement of an acoustic field distribution in the proximity of the human head and the numerical simulation of observed phenomena.
His scientific interests concern the issues of the design and implementation of the digital acoustic signal processing and modern metods of the numerical simulation in acoustics.
His other interests include artistic drawing, graphic art, composition and production of electronic music.
Karol Lisowski, MSc, Eng.
Karol Lisowski was born in 1986 in Mragowo. In 2011 he graduated from the Gdabnk University of Technology, Faculty of Electronics, Telecommunication and Informatics. His subject of MSc. Eng. thesis was related to transcoding strategies of multimedia content in distributed surveillance system. He is a PhD Student of the Multimedia Systems Department. His scientific interests concern the issues of video surveillance systems, re-identification algorithms, artificial intelligence as well as creating of the bevaviour models. He is the author of about 10 publications (including 3 articles in journals and and 2 chapters in monographs). Moreover, he participated in four European research projects.
Bartłomiej Mróz, MSc., Eng.
Bartłomiej Mróz was born in 1993 in Gdańsk. In 2017 he graduated with honours from Gdańsk University of Technology, obtaining a master’s degree in engineering. He spent two years of studies abroad – one year on both first and second degree, respectively: University of Ljubljana (Slovenia) and Graz University of Technology (Austria). During his studies in Austria he conducted entitled Externalisation and Distance in Ambisonic Rendering on Headphones. In partcicular, it is worth mentioning the second exchange – on the last year of master’s degree – which not only brought a master thesis, but also resulted in further cooperation with the Institute of Electronic Music and Acoustics at the University of Music and Performing Arts Graz (Das Institut für Elektronische Musik und Akustik – IEM Graz).
Marta Stefaniak, MSc., Eng.
Marta Stefaniak was born in 1992 in Gdansk. In 2018 she graduated from the Faculty of Electronics, Telecommunications and Informatics at Gdansk University of Technology in the Multimedia Systems Department. The subject of her B.Sc. thesis was Application of fast cameras for measurement of string vibration. Her MSc. thesis was Examination of selected musical instruments properties using numerical and measurement methods.
She is interested in recording and editing video materials including fast cameras, photography and traveling.
Dawid Weber, MSc., Eng.
Dawid Weber was born in 1992 in Toruń. In 2017 he finished studies on Gdańsk University of Technology, on faculty of Electronics, Telecommunication and Informatics on specialty of Sound and Vision Engineering. His engineering thesis was about creating guitar effects processor on mobile devices and also his master thesis was about recording band with using various microphones techniques and subjective evaluation of sound acquisitions techniques.
His scientific interests focus around realization of recording band and sound processing. Other interest are making short films, mood videos, computer graphics and hard rock music.
Piotr Hoffmann, PhD, Eng.
PhD, Eng. Piotr Hoffmann, in 2012 he graduated from the Faculty of Electronics, Telecommunications and Information Technology at the Gdansk University of Technology and received the Master of Science degree in engineering. The subject of the diploma thesis was connected with the design of the theatre room sound system. In 2016 he graduated from the Faculty of Management at Gdansk University of Technology with a specialisation in IT projects management. In 2019 he defended with honours his doctoral thesis entitled " The method and system of adaptive control of synthesis parameters algorithm for low-frequency music sounds”.
Since 2013 he has been working in national and international research and development projects (ADDPRIV, SYNAT, MODALITY, IDENT, INZNAK). Since 2015 he coordinates research work in R+D projects. At present he works as a managing director in the INZNAK project.
He is the author and co-author of a total of over 30 articles, conference papers and chapters in books. In addition, he is a co-author of two patents and eight applications for patent.
His scientific interests are mainly related to the acoustics in the context of playing music signals and authentication of identity using biometric technologies.
Maciej Szczodrak, Ph.D, Eng.
Maciej Szczodrak was born in Gdynia, Poland. He received his MSc. degree from the Gdansk University of Technology in 2006. His thesis concerned implementation of algorithms for open air sound propagation analysis.
He is interested in audio and video processing, environmental acoustics. He is also concerned about programming.
Olga Szmit, MSc., Eng.
Olga Szmit received her MSc. degree from Chemical Technology, Gdansk University of Technology. In 2014 she also graduated from University of Business and Administration, Ecoenergetic: Administration of renewable energy sources.
She gained project administration experience during realization of many projects, e.g. Basic technology of producing cover shields form modified ballistic gel.
Born in Poznan/Poland he begun his music education with piano at the age of 7, and continued through his years in college in England. After obtaining his diploma in Audio Engineering from SAE Paris, he engaged in 12 years of intensive studio work for independent artists, labels and TV stations. A few years into his sound engineering career he begun writing music for films which proved to be an ongoing passion and an important part of his work. He has since also become a song writer.
In 2006 he co-founded APS - a company with focus on manufacturing high quality active studio monitors. Presently, Kris lives in Poland, helping in the running of APS and his own production company AudioPlanet, while continuing his music production and composing career.
All throughout his career Kris gave a lot of importance to education. He has been giving workshops to young people for the last 18 years and has recently started working with students and staff from Gdansk University of Technology. He has also worked as a consultant on a number of projects on studio construction.
Some of his other interests are education, psychology and motorcycling.
Zofia Rutka, MSc
Daniel Wiśniewski was born in 1993. He has over five years of experience as a sound and light master in the theatre and FOH engineer at concerts, conferences and outdoor events. He began studying Electrotechnics at the Gdańsk University of Technology in 2018. His interests are: new technologies, IT news, automotive and diving.