Vítor J Sá | Instituto Politecnico do Porto (original) (raw)
Papers by Vítor J Sá
commercial advantage and that copies bear this notice and the full citation on the first page. Co... more commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for components of this work owned by others than ACM must be honored. Abstracting with credit is permitted. To copy otherwise, to republish, to post on servers, or to redistribute to lists, requires prior specific permission and/or a fee. Request permissions from Publications Dept., ACM, Inc., fax +1 (212) 869-0481, or per m i s si o ns @a c m. or g .
The current state of information and communication technologies, pointing out the massive use of ... more The current state of information and communication technologies, pointing out the massive use of computer graphics, is instigating new possibilities for data visualization and analysis. Large amounts of data can be represented in an effective way of understanding by the ...
In a global context of multimodal man-machine interaction, we approach a wide spectrum of fields,... more In a global context of multimodal man-machine interaction, we approach a wide spectrum of fields, such as software engineering, intelligent communication and speech dialogues. This paper presents technological aspects of the shifting from the traditional desktop interfaces to more expressive, natural, flexible and portable ones, where more persons, in a greater number of situations, will be able to interact with computers. Speech appears to be one of the best forms of interaction, especially in order to support non-skilled users. Modalities such as speech, among others, tend to be very relevant to accessing information in our future society, in which mobile devices will play a preponderant role. Therefore, we are placing an emphasis on verbal communication in open environments (Java/XML) using software agent technology.
Kalpa publications in computing, Feb 16, 2023
We live in an era daily inundated with information, and the economy of attention makes us far fro... more We live in an era daily inundated with information, and the economy of attention makes us far from the truth. The present study has its core to study the creation, use and sharing of videos originated by artificial intelligence that can make it appear that a person says or does something, although he has never said or done anything of the kind. This content is called deepfake. The problem is the way this content is propagated, which for the untrained eye it can be seen as authentic. Quantitative research was carried out, through an inquiry and a literature review.
Déjà Vu: a user study using images for authentication. Em Proceedings of the 9th conference on US... more Déjà Vu: a user study using images for authentication. Em Proceedings of the 9th conference on USENIX Security Symposium-Volume 9 (pp 4-4). Denver, Colorado: USENIX Association.
Advances in higher education and professional development book series, Jun 30, 2023
Congreso XoveTIC: impulsando el talento científico (6º. 2023. A Coruña)
Exposure therapy is a type of psychotherapy where the patient is gradually exposed to a fear situ... more Exposure therapy is a type of psychotherapy where the patient is gradually exposed to a fear situation. Patients may present different degrees of phobia, and the degree of phobia of each patient changes throughout the treatment. The use of Interactive Virtual Reality Adaptive Environments, where the interaction is personalized through real-time biofeedback mechanisms, allows the environment to adapt to the patients and their evolution throughout the treatment. The Artificial Intelligence affective algorithms continuously monitor the patient’s behavioral data and physiological responses to adjust the intensity and number of the stimuli. This real-time adaptation aims to personalize and optimize the exposure process, gradually desensitizing patients to their fears
The current state of information and communication technologies, pointing out the massive use of ... more The current state of information and communication technologies, pointing out the massive use of computer graphics, is instigating new possibilities for data visualization and analysis. Large amounts of data can be represented in an effective way of understanding by the ...
Prefácio O livro que aqui tenho o privilégio de prefaciar é detentor de uma enorme pertinência e ... more Prefácio O livro que aqui tenho o privilégio de prefaciar é detentor de uma enorme pertinência e atualidade, fazendo, desde logo, todo o sentido em começar por felicitar a equipa de coordenadores (Professores Alexandra Esteves, Manuel Antunes da Cunha,
The performance of a biometric system depends on the accuracy, the processing speed, the template... more The performance of a biometric system depends on the accuracy, the processing speed, the template size, and the time necessary for enrolment. This last factor is not much addressed in literature. In this work we collected information about the users' availability for enrolment in respect to face recognition biometrics. Were involved in testing 26 randomly chosen people. The results are presented globally, by sex, by age group and by previous experience in the use of the technology. We found that there is a generalized positive predisposition for enrolment that is expressed in some by the predisposition to try for many times and in others to try over a long time, and that it may be the youngest and the oldest the least available.
The armed forces are a critical component of the national security strategy of several European c... more The armed forces are a critical component of the national security strategy of several European countries. Despite the peace that has succeeded the cold war, several armies, in peacetime, have elements recruited with promises of individual opportunities. The countries have two forms of recruitment of their troops: by volunteering or by mandatory incorporation. Following the trends of the modern world, interconnected in a network, it becomes essential to the institutions to mark their presence on the Internet. The Armed Forces in their various branches are no exception; there are numerous sites with relevant information, being used as a channel for dissemination and fundraising. Since young people represent a large share of the population using the Internet, and this is the target population for recruitment, it becomes mandatory to use the internet as a communication channel between them. It was carried out a qualitative study of all sites of European armed forces, and their branches, in order to assess their quality and differences. The approach focused on the evaluation of sites for their ability to inform, update, quantity and quality of content, service availability, use and visual attractiveness, and ease of communication. The study has also tried to verify if the countries with volunteer incorporation were producing websites with higher levels of quality, reflecting the need to invest in order to recruit. On the other hand, countries with compulsive incorporation could have lower investments in their websites, once the satisfaction of the need for staff is guarantied. We considered 38 countries, with an initial usability study where data about the characteristics considered important for proper construction of a website as well as for a good and easy relationship with the user of this type of site were collected. This research defined the parameters to evaluate the sites and groups were created with the parameters of the different areas of analysis of those sites. The evaluation shows that there are differences in quality of sites for each of the countries evaluated in terms of graphics, usability and content, and that where there is a greater difference between the countries is on the number of existing sites by country. It is clear that there are countries that invest strategically in this area while others do not. It was also clear that there is a difference between Eastern and Western Europe in the quality and investment made in the sites of their armed forces. Dividing the countries by their incorporation system, the differences are smaller, both in terms of number of sites for the military, either as to the average assessment of each scheme. In countries where the incorporation is mandatory, investment in independent sites for each branch has not been neglected for a considerable part of the countries, a little more than half. But it is in countries where recruitment is made on a voluntary basis that there are more sites for the different branches, which may indicate an existing competitiveness for staff recruitment.
Tese de doutoramento do Programa Doutoral em Tecnologias e Sistemas de InformaçãoEsta tese consis... more Tese de doutoramento do Programa Doutoral em Tecnologias e Sistemas de InformaçãoEsta tese consiste num estudo de viabilidade (social e tecnológica) de uma solução de autenticação com recurso à biometria comportamental de dinâmica gestual (restringida ao gesto de apontar) e à biometria cognitiva de condutividade da pele. O problema da transmissibilidade do segredo de autenticação, seja por algo que se sabe ou por algo que se possui, tem-nos conduzido à utilização de tecnologias biométricas, em que o segredo consiste em algo que se é ou algo que se faz. No entanto, as biometrias podem sofrer do problema da replicabilidade, mesmo quando se trata de biometrias comporta mentais, o que nos leva às biometrias cognitivas. Para além disso, no controlo de acesso lógico coloca-se o problema da validade da autenticação ao longo do tempo. Este problema, por vezes denominado problema de autenticação contínua, é mais facilmente ultrapassado com recurso a sistemas multimodais, uma vez que diferent...
Neste artigo fazemos numa breve contextualização teórica sobre a origem do Catolicismo em Portuga... more Neste artigo fazemos numa breve contextualização teórica sobre a origem do Catolicismo em Portugal, a sua evolução histórica e a importância na vida social das pessoas, para nos debruçarmos sobre a relação que a Igreja tem evidenciado no recurso aos meios de comunicação, mais concretamente na utilização da Internet. Sendo Portugal um país maioritariamente católico, pretende-se saber em que nível de maturidade se situa a utilização da Internet nas Paróquias Católicas Portuguesas, cuja investigação se centrará numa pesquisa e análise rigorosa feita aos sítios Web das mesmas.
This work aims the creation of virtual worlds by working teams with resource to advanced interact... more This work aims the creation of virtual worlds by working teams with resource to advanced interaction techniques, such as speech commands and gestures, as well as the resource to portable devices. The physical characteristics of virtual reality environments lead us to a different kind of user interfaces. However, we found some usefulness on the classic WIMP paradigm, which we also apply by using a PDA, in order to complement the interaction possibilities. In terms of application description we use the Virtual Reality Modeling Language. One of the main goals is the separation/combination of VRML files in order to allow the work to be cared out individually by the members of the team, and later combine the results to produce the global virtual world.
Biometric systems are increasingly being used as a means for authentication to provide system sec... more Biometric systems are increasingly being used as a means for authentication to provide system security in modern technologies. The performance of a biometric system depends on the accuracy, the processing speed, the template size, and the time necessary for enrollment. While much research has focused on the first three factors, enrollment time has not received as much attention. In this work, we present the findings of our research focused upon studying user's behavior when enrolling in a biometric system. Specifically, we collected information about the user's availability for enrollment in respect to the hand recognition systems (e.g., hand geometry, palm geometry or any other requiring positioning the hand on an optical scanner). A sample of 19 participants, chosen randomly apart their age, gender, profession and nationality, were used as test subjects in an experiment to study the patience of users enrolling in a biometric hand recognition system.
Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering, 2012
This article presents an analysis of the adoption the Citizen Card in Portugal based on a survey,... more This article presents an analysis of the adoption the Citizen Card in Portugal based on a survey, in which 601 citizens participated. The survey focused on the knowledge of the card and of its features, as well as in the digital signature capabilities. First the survey population was informed about the concept of the Citizen Card, its applicability, and the technological mechanisms associated with their use. We extracted a set of conclusions, which may be useful to countries seeking to implement this type of technology/procedures.
Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering, 2012
This article presents the results of a systematic inquiry about the perception of the Portuguese ... more This article presents the results of a systematic inquiry about the perception of the Portuguese on the biometric technology, which involved 606 citizens. It is presented the principal biometrics and the main concepts on its evaluation. Following a simple method consisting in a survey by questionnaire, the most relevant conclusions are presented.
commercial advantage and that copies bear this notice and the full citation on the first page. Co... more commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for components of this work owned by others than ACM must be honored. Abstracting with credit is permitted. To copy otherwise, to republish, to post on servers, or to redistribute to lists, requires prior specific permission and/or a fee. Request permissions from Publications Dept., ACM, Inc., fax +1 (212) 869-0481, or per m i s si o ns @a c m. or g .
The current state of information and communication technologies, pointing out the massive use of ... more The current state of information and communication technologies, pointing out the massive use of computer graphics, is instigating new possibilities for data visualization and analysis. Large amounts of data can be represented in an effective way of understanding by the ...
In a global context of multimodal man-machine interaction, we approach a wide spectrum of fields,... more In a global context of multimodal man-machine interaction, we approach a wide spectrum of fields, such as software engineering, intelligent communication and speech dialogues. This paper presents technological aspects of the shifting from the traditional desktop interfaces to more expressive, natural, flexible and portable ones, where more persons, in a greater number of situations, will be able to interact with computers. Speech appears to be one of the best forms of interaction, especially in order to support non-skilled users. Modalities such as speech, among others, tend to be very relevant to accessing information in our future society, in which mobile devices will play a preponderant role. Therefore, we are placing an emphasis on verbal communication in open environments (Java/XML) using software agent technology.
Kalpa publications in computing, Feb 16, 2023
We live in an era daily inundated with information, and the economy of attention makes us far fro... more We live in an era daily inundated with information, and the economy of attention makes us far from the truth. The present study has its core to study the creation, use and sharing of videos originated by artificial intelligence that can make it appear that a person says or does something, although he has never said or done anything of the kind. This content is called deepfake. The problem is the way this content is propagated, which for the untrained eye it can be seen as authentic. Quantitative research was carried out, through an inquiry and a literature review.
Déjà Vu: a user study using images for authentication. Em Proceedings of the 9th conference on US... more Déjà Vu: a user study using images for authentication. Em Proceedings of the 9th conference on USENIX Security Symposium-Volume 9 (pp 4-4). Denver, Colorado: USENIX Association.
Advances in higher education and professional development book series, Jun 30, 2023
Congreso XoveTIC: impulsando el talento científico (6º. 2023. A Coruña)
Exposure therapy is a type of psychotherapy where the patient is gradually exposed to a fear situ... more Exposure therapy is a type of psychotherapy where the patient is gradually exposed to a fear situation. Patients may present different degrees of phobia, and the degree of phobia of each patient changes throughout the treatment. The use of Interactive Virtual Reality Adaptive Environments, where the interaction is personalized through real-time biofeedback mechanisms, allows the environment to adapt to the patients and their evolution throughout the treatment. The Artificial Intelligence affective algorithms continuously monitor the patient’s behavioral data and physiological responses to adjust the intensity and number of the stimuli. This real-time adaptation aims to personalize and optimize the exposure process, gradually desensitizing patients to their fears
The current state of information and communication technologies, pointing out the massive use of ... more The current state of information and communication technologies, pointing out the massive use of computer graphics, is instigating new possibilities for data visualization and analysis. Large amounts of data can be represented in an effective way of understanding by the ...
Prefácio O livro que aqui tenho o privilégio de prefaciar é detentor de uma enorme pertinência e ... more Prefácio O livro que aqui tenho o privilégio de prefaciar é detentor de uma enorme pertinência e atualidade, fazendo, desde logo, todo o sentido em começar por felicitar a equipa de coordenadores (Professores Alexandra Esteves, Manuel Antunes da Cunha,
The performance of a biometric system depends on the accuracy, the processing speed, the template... more The performance of a biometric system depends on the accuracy, the processing speed, the template size, and the time necessary for enrolment. This last factor is not much addressed in literature. In this work we collected information about the users' availability for enrolment in respect to face recognition biometrics. Were involved in testing 26 randomly chosen people. The results are presented globally, by sex, by age group and by previous experience in the use of the technology. We found that there is a generalized positive predisposition for enrolment that is expressed in some by the predisposition to try for many times and in others to try over a long time, and that it may be the youngest and the oldest the least available.
The armed forces are a critical component of the national security strategy of several European c... more The armed forces are a critical component of the national security strategy of several European countries. Despite the peace that has succeeded the cold war, several armies, in peacetime, have elements recruited with promises of individual opportunities. The countries have two forms of recruitment of their troops: by volunteering or by mandatory incorporation. Following the trends of the modern world, interconnected in a network, it becomes essential to the institutions to mark their presence on the Internet. The Armed Forces in their various branches are no exception; there are numerous sites with relevant information, being used as a channel for dissemination and fundraising. Since young people represent a large share of the population using the Internet, and this is the target population for recruitment, it becomes mandatory to use the internet as a communication channel between them. It was carried out a qualitative study of all sites of European armed forces, and their branches, in order to assess their quality and differences. The approach focused on the evaluation of sites for their ability to inform, update, quantity and quality of content, service availability, use and visual attractiveness, and ease of communication. The study has also tried to verify if the countries with volunteer incorporation were producing websites with higher levels of quality, reflecting the need to invest in order to recruit. On the other hand, countries with compulsive incorporation could have lower investments in their websites, once the satisfaction of the need for staff is guarantied. We considered 38 countries, with an initial usability study where data about the characteristics considered important for proper construction of a website as well as for a good and easy relationship with the user of this type of site were collected. This research defined the parameters to evaluate the sites and groups were created with the parameters of the different areas of analysis of those sites. The evaluation shows that there are differences in quality of sites for each of the countries evaluated in terms of graphics, usability and content, and that where there is a greater difference between the countries is on the number of existing sites by country. It is clear that there are countries that invest strategically in this area while others do not. It was also clear that there is a difference between Eastern and Western Europe in the quality and investment made in the sites of their armed forces. Dividing the countries by their incorporation system, the differences are smaller, both in terms of number of sites for the military, either as to the average assessment of each scheme. In countries where the incorporation is mandatory, investment in independent sites for each branch has not been neglected for a considerable part of the countries, a little more than half. But it is in countries where recruitment is made on a voluntary basis that there are more sites for the different branches, which may indicate an existing competitiveness for staff recruitment.
Tese de doutoramento do Programa Doutoral em Tecnologias e Sistemas de InformaçãoEsta tese consis... more Tese de doutoramento do Programa Doutoral em Tecnologias e Sistemas de InformaçãoEsta tese consiste num estudo de viabilidade (social e tecnológica) de uma solução de autenticação com recurso à biometria comportamental de dinâmica gestual (restringida ao gesto de apontar) e à biometria cognitiva de condutividade da pele. O problema da transmissibilidade do segredo de autenticação, seja por algo que se sabe ou por algo que se possui, tem-nos conduzido à utilização de tecnologias biométricas, em que o segredo consiste em algo que se é ou algo que se faz. No entanto, as biometrias podem sofrer do problema da replicabilidade, mesmo quando se trata de biometrias comporta mentais, o que nos leva às biometrias cognitivas. Para além disso, no controlo de acesso lógico coloca-se o problema da validade da autenticação ao longo do tempo. Este problema, por vezes denominado problema de autenticação contínua, é mais facilmente ultrapassado com recurso a sistemas multimodais, uma vez que diferent...
Neste artigo fazemos numa breve contextualização teórica sobre a origem do Catolicismo em Portuga... more Neste artigo fazemos numa breve contextualização teórica sobre a origem do Catolicismo em Portugal, a sua evolução histórica e a importância na vida social das pessoas, para nos debruçarmos sobre a relação que a Igreja tem evidenciado no recurso aos meios de comunicação, mais concretamente na utilização da Internet. Sendo Portugal um país maioritariamente católico, pretende-se saber em que nível de maturidade se situa a utilização da Internet nas Paróquias Católicas Portuguesas, cuja investigação se centrará numa pesquisa e análise rigorosa feita aos sítios Web das mesmas.
This work aims the creation of virtual worlds by working teams with resource to advanced interact... more This work aims the creation of virtual worlds by working teams with resource to advanced interaction techniques, such as speech commands and gestures, as well as the resource to portable devices. The physical characteristics of virtual reality environments lead us to a different kind of user interfaces. However, we found some usefulness on the classic WIMP paradigm, which we also apply by using a PDA, in order to complement the interaction possibilities. In terms of application description we use the Virtual Reality Modeling Language. One of the main goals is the separation/combination of VRML files in order to allow the work to be cared out individually by the members of the team, and later combine the results to produce the global virtual world.
Biometric systems are increasingly being used as a means for authentication to provide system sec... more Biometric systems are increasingly being used as a means for authentication to provide system security in modern technologies. The performance of a biometric system depends on the accuracy, the processing speed, the template size, and the time necessary for enrollment. While much research has focused on the first three factors, enrollment time has not received as much attention. In this work, we present the findings of our research focused upon studying user's behavior when enrolling in a biometric system. Specifically, we collected information about the user's availability for enrollment in respect to the hand recognition systems (e.g., hand geometry, palm geometry or any other requiring positioning the hand on an optical scanner). A sample of 19 participants, chosen randomly apart their age, gender, profession and nationality, were used as test subjects in an experiment to study the patience of users enrolling in a biometric hand recognition system.
Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering, 2012
This article presents an analysis of the adoption the Citizen Card in Portugal based on a survey,... more This article presents an analysis of the adoption the Citizen Card in Portugal based on a survey, in which 601 citizens participated. The survey focused on the knowledge of the card and of its features, as well as in the digital signature capabilities. First the survey population was informed about the concept of the Citizen Card, its applicability, and the technological mechanisms associated with their use. We extracted a set of conclusions, which may be useful to countries seeking to implement this type of technology/procedures.
Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering, 2012
This article presents the results of a systematic inquiry about the perception of the Portuguese ... more This article presents the results of a systematic inquiry about the perception of the Portuguese on the biometric technology, which involved 606 citizens. It is presented the principal biometrics and the main concepts on its evaluation. Following a simple method consisting in a survey by questionnaire, the most relevant conclusions are presented.