Rui António dos Santos Cruz
@ulisboa.pt
Instituto Superior Técnico, Universidade de Lisboa
Scopus Publications
Scopus Publications
Pedro Maximino, Rui S. Cruz, and Miguel L. Pardal
IEEE
In an age where citizens are constantly moving between different places, transport demand is extremely high, and so, it is important to have sophisticated public transportation systems in place to ensure a sustainable development of urban areas and meet the needs of citizens. Public transport operators consequently need to provide reliable services in order to minimize disruption events that can affect the vehicles and their drivers, such as breakdowns, accidents or illnesses. The project here described focuses on the type of events and approaches related with the vehicle drivers and the identification of both their performance profiles and health condition while in operation. For that purpose, existing nonintrusive technologies present on the vehicle are leveraged, able to collect data related to physiological measurements taken in realtime. Such sensitive data will be processed, stored and shared in a secure manner, using blockchain-based technologies, so that only authenticated and authorized parties will be able to access the data, according to their clearance level, through an Application Programming Interface (API) designed for that purpose. The architecture of the system will be microservices-based, with components deployed at different infrastructure levels—from On Board Units (OBUs) in vehicles up to cloud-based subsystems.
Manuel Duarte Mascarenhas and Rui Santos Cruz
IEEE
Miguel Moreira Oliveira and Rui Santos Cruz
IEEE
Sara Rouhani, Rafael Belchior, Rui S. Cruz, and Ralph Deters
Springer Science and Business Media LLC
Auditing provides an essential security control in computer systems, by keeping track of all access attempts, including both legitimate and illegal access attempts. This phase can be useful to the context of audits, where eventual misbehaving parties can be held accountable. Blockchain technology can provide trusted auditability required for access control systems. In this paper, we propose a distributed \\ac{ABAC} system based on blockchain to provide trusted auditing of access attempts. Besides auditability, our system presents a level of transparency that both access requestors and resource owners can benefit from it. We present a system architecture with an implementation based on Hyperledger Fabric, achieving high efficiency and low computational overhead. The proposed solution is validated through a use case of independent digital libraries. Detailed performance analysis of our implementation is presented, taking into account different consensus mechanisms and databases. The experimental evaluation shows that our presented system can process 5,000 access control requests with the send rate of 200 per second and a latency of 0.3 seconds.
Miguel Oliveira and Rui S. Cruz
IEEE
To support new and more complex software systems, tools, and applications, the IT Infrastructures have evolved to be more flexible and grow both in size and complexity. To manage those Infrastructures, several tools are used. For large datacenters and public cloud infrastructures, complex managements systems have been developed in-house, according to specific implementations and philosophies. However, for the small, business owned, infrastructures, such tools are usually used independently. In this paper, we present the architecture of a new Orchestrator tool that aims to provide a single point of management, while also maintaining a resource inventory, by means of a Distributed Ledger, in order to maintain records of all the changes in the infrastructure, ensuring traceability over past changes, and even allowing for rollback of certain actions.
Mariana Cruz and Rui S. Cruz
IEEE
Railway networking systems are critical infrastructures that must support fast, reliable and low delay communications. Technologies still used in those infrastructures---such as GSM-R, evolving into LTE-R are becoming more complex, yet more flexible, and evolving to "software defined" architectures. The technologies presented and explored in this work are expected to change the future of these types of critical systems. The main goal of this work is to study the key benefits of using the SDN model to control the next generation railways networking infrastructures. The safety, security and correctness properties of SDN controllers in high availability railway networks will be analyzed, for compliance with the European Rail Traffic Management System (ERTMS)/European Train Control System (ETCS) specifications, and in the context of a real project being deployed in a Portuguese Railway by Thales Portugal. From the analysis of the project requirements and the selected network equipment, it was possible to evaluate and propose adequate methods to automatically derive network re-configuration strategies, namely in case of failure events---e.g., preventing packet loss affecting vital railway traffic signaling procedures---in order to reduce field intervention and complexity in those infrastructures.
Carolina Fernandes and Rui Cruz
The problem between Over-the-Top (OTT) and Communications Service Provider (CSP), namely for multimedia streaming services, is not new and has been a topic much discussed in the TM Forum. At time of writing, a technical solution that would benefit both parties has not yet been presented. With the existing model (no operational integration), both OTTs and CSPs are dissatisfied. This paper proposes a technical solution that can be beneficial to both parties and can potentially solve the existing conflicts. The solution presents the high-level design of Business Processes to integrate OTT Service Platforms in CSP Operations. Some hypothetical, but close to reality scenarios were defined in order to show how the model could be applied. The design of the model incorporates information and suggestions collected from Portuguese CSPs. To evaluate the accuracy of the design methodology, a set of interviews were conducted with industry experts in the sector, who evaluated each process model of the solution. A set of surveys from end users of those types of services was also conducted, in order to understand their opinions about the ideas used for the construction of the model.
Carolina Fernandes and Rui Cruz
IEEE
The problem between Over-the-Top (OTT) and Communications Service Provider (CSP), namely for multimedia streaming services, is not new and has been a topic much discussed in the TM Forum. At time of writing, a technical solution that would benefit both parties has not yet been presented. With the existing model (no operational integration), both OTTs and CSPs are dissatisfied. This paper proposes a technical solution that can be beneficial to both parties and can potentially solve the existing conflicts. The solution presents the high-level design of Business Processes to integrate the OTT Service Platforms in CSP Operations. Some hypothetical, but close to reality scenarios were defined in order to show how the model could be applied. The design of the models incorporates information and suggestions collected from Portuguese CSPs. To evaluate the accuracy of the methodology, a set of interviews were conducted with industry experts, who evaluated each model of the solution. A set of surveys from users of these types of services was also conducted, in order to understand their opinions about the ideas used in the construction of the model.
Antonio Calcada and Rui Cruz
IEEE
Aging demographic, intermittent treatment and increasing costs of care characterise the situation the Healthcare sector is facing. Further, the increase in access and use of more sophisticated, cheaper and wearable technologies, sets the opportunity for the development of novel Healthcare related solutions that can bring a positive and transformative change in the Healthcare landscape. This work presents the development of an alarm algorithm and respective monitoring strategy for an outpatient scenario employing wearable technology. The research methodology that was followed allowed to identify and determine the Vital Body Signs (VBSs) and thresholds characterising medical conditions and deviations from the normal physiological state. A survey conducted among Healthcare experts, provided the validation, with agreement rates over 71%, of the set of VBSs and respective thresholds to integrate in the alarm algorithm in order to enable the detection of both life-threatening and increased Health risk situations. The validation tests performed through the analysis of Health Data sets, enabled the design of the proposed model, and also to identify its limitations.
Rui S. Cruz and Miguel Casquilho
IEEE
This study is based on a concrete problem in a fertilizer factory about the estimation of process parameters: to calculate the mean and standard deviation from weights (sums only)of loads of unequal (known)number of bags (“equal” case being trivial). With many distribution depots., the data for each depot must be collected for processing. These are addressed in a Cloud Computing., big-data framework. The use of Apache Spark is described and adopted., as advantageous over Hadoop due to “in-memory computation” and Resilient Distributed Dataset. The computation uses Terraform and Ansible as configuration tool, and is deployed on the Google Cloud Platform. The evaluation preliminary tests confirmed good accuracy and produced low runtimes.
Rui Cruz, Joao Jardim, Joao Mira, and Carlos Teixeira
IEEE
Urban mobility is facing significant challenges nowadays; several factors affect the way people move, mainly but not only, within cities and large metropolitan areas. These factors are usually related to the way of life and mobility needs of the human being, leading to social constraints and environmental issues, overcrowding the undersized transportation networks and infrastructures. The pressure for better planning, improved sustainability and governance on transportation is therefore higher, with a shift in focus to technological changes in order to improve policies for all stakeholders involved on mobility. In this scenario, rail is one of the most affected transportation modes (mainly within large urban and metropolitan areas), having to deal with increasing demands in limited infrastructures, a situation that leads to congestion on operations and safety problems. Improvement or evolution in rail is traditionally done at significant costs, and is highly dependent on political decisions, making it difficult for rail to be in line with the evolution of mobility systems. However, the modal shift towards public transport and the high potential of rail within green and sustainable transport modes, gives it the opportunity to grow, according to the "Smart Rail" vision. This paper provides an overview on the current status and trends of what can be defined as "Smart Mobility"—presenting and discussing not just the benefits but also some of the challenges on its implementation— with relevance to the rail transportation mode. Smart Rail, as the future of the railways, relying upon "Smart" technologies and further related innovation steps, also described and discussed, will be the basis for sustainable and safe mobility.
Rui Santos Cruz and Mário Serafim Nunes
Springer Science and Business Media LLC
Peer-to-peer (P2P) streaming solutions are changing the way real-time multimedia transmission is distributed over the Internet. The advances in video coding, like Scalable Video Coding, also turns possible high-quality/definition video distribution and consumption. The recent push in using the standard HTTP protocol for streaming videos in the World Wide Web, is also making converged entertainment services come closer to global deployment across TV, Tablet and mobile devices. The combination of Scalable Video, P2P networks and Web technologies for transmitting high-quality live and time-shifted media contents, is a potential area of innovation and a very actual research topic. This paper describes the architecture of a quality-centric P2P distribution network supporting adaptive and scalable streamable media, that decouples the transport mechanisms from the media content type and structure (video, audio, timed-data, timed-text), irrespective of their encoding schemes. The set of P2P streaming protocols designed for the network enables streaming of live and on-demand media, with very low signaling cost. Prototypes of the P2P network components were implemented and integrated in the streaming platform of EU FP7 SARACEN Project. A suite of tests for evaluation of the performance of the solution demonstrates that it keeps a fairly stable quality level with reduced amplitude and frequency of variations, raising the overall quality perceived by the end-user.
Jânio M. Monteiro, Rui S. Cruz, Charalampos Z. Patrikakis, Nikolaos C. Papaoulakis, Carlos T. Calafate, and Mário S. Nunes
IGI Global
The Internet as a video distribution medium has seen a tremendous growth in recent years. Currently, the transmission of major live events and TV channels over the Internet can easily reach hundreds or millions of users trying to receive the same content using very distinct receiver terminals, placing both scalability and heterogeneity challenges to content and network providers. In private and well-managed Internet Protocol (IP) networks these types of distributions are supported by specially designed architectures, complemented with IP Multicast protocols and Quality of Service (QoS) solutions. However, the Best-Effort and Unicast nature of the Internet requires the introduction of a new set of protocols and related architectures to support the distribution of these contents. In the field of file and non-real time content distributions this has led to the creation and development of several Peer-to-Peer protocols that have experienced great success in recent years. This chapter presents the current research and developments in Peer-to-Peer video streaming over the Internet. A special focus is made on peer protocols, associated architectures and video coding techniques. The authors also review and describe current Peer-to-Peer streaming solutions.
António Pedro Inácio, Rui Santos Cruz, and Mário Serafim Nunes
Springer Science and Business Media LLC
The continuous improvement in the delivery of advanced video services, along with evolved technical conditions at the client side, contributed to the appearance of new methods for the evaluation of quality of service (QoS) and quality of experience (QoE) from the user’s point of view. This article describes the development of a model that correlates QoS parameters and QoE factors with impact on the variation of the user’s perception of the quality. A quality assessment test was performed with 40 participants that ranked more than 140 videos. The detailed analysis of the collected data from the test allowed to conclude that all the considered factors had significant impact on the perceived quality. Those factors were aggregated in a single model using linear regression techniques to join their behavior and associate adequate weights to each factor. The results from validity tests of the model were encouraging, achieving 99 % of accuracy. This model can be considered a new no-reference metric to infer the perceived quality, applicable in many contexts, but essentially as a tool for service providers to estimate the rank customers may give to a content.
Mikoaj Leszczuk, Rui Cruz, Dawid Juszka, Mario Nunes, Lucjan Janowski, Charalampos Patrikakis, Micha Grega, and Stavros Papapanagiotou
IEEE
Recent advances in video distribution over the Internet have inevitably led to the need for accompanying the video related value-added services with the means for maintaining integrity and quality of distributed media to optimize Quality of Experience (QoE). Current systems cover the aspects of maintaining the quality of 2D (only) media by conducting user requirements surveys and 2D QoE assessments. This paper presents the work performed in the EU FP7 SARACEN research project on personalized 3D media streaming over P2P architectures, together with evaluation tests and results as regards scalable and adaptive coding for 3D video streams.
Jânio M. Monteiro, Rui S. Cruz, Charalampos Z. Patrikakis, Nikolaos C. Papaoulakis, Carlos Tavares Calafate, and Mário S. Nunes
IGI Global
The Internet as a video distribution medium has seen a tremendous growth in recent years. Currently, the transmission of major live events and TV channels over the Internet can easily reach hundreds or millions of users trying to receive the same content using very distinct receiver terminals, placing both scalability and heterogeneity challenges to content and network providers. In private and well-managed Internet Protocol (IP) networks these types of distributions are supported by specially designed architectures, complemented with IP Multicast protocols and Quality of Service (QoS) solutions. However, the Best-Effort and Unicast nature of the Internet requires the introduction of a new set of protocols and related architectures to support the distribution of these contents. In the field of file and non-real time content distributions this has led to the creation and development of several Peer-to-Peer protocols that have experienced great success in recent years. This chapter presents the current research and developments in Peer-to-Peer video streaming over the Internet. A special focus is made on peer protocols, associated architectures and video coding techniques. The authors also review and describe current Peer-to-Peer streaming solutions.
Joana Palhais, Rui S. Cruz, and Mário S. Nunes
Springer Berlin Heidelberg
Nowadays, Service Providers are increasingly concerned about the concept of Quality of Experience (QoE),, even more, when talking about Internet TV or WebTV, where no guarantees of delivery are provided. This paper describes the research and the results on the influence of the level of interest (on a particular sport) in the subjective quality assessment of the corresponding broadcasted media. This analysis is motivated by the work being developed in the European Project My-eDirector 2012, which has the capability to cover the London Olympic Games 2011 via the Web. Therefore, a subjective test was prepared and performed where each observer visioned and assessed the perceived video quality of a set of six sports, encoded in four different bitrate/resolution sets. From the analysis of the collected data it is possible to demonstrate that the interest level has a strong influence in the subjective assessment of the video quality. Based on these results, an empiric formula was deduced to estimate the Mean Opinion Source (MOS) as a function of bitrate and interest level.
Charalampos Patrikakis, Nikolaos Papaoulakis, Panagiotis Papageorgiou, Aristodemos Pnevmatikakis, Paul Chippendale, Mario Nunes, Rui Santos Cruz, Stefan Poslad, and Wang Zhenchen
Institute of Electrical and Electronics Engineers (IEEE)
This article presents a platform that lets users direct their own coverage of large athletic events, letting them set up their own virtual director and orchestrate event viewing according to their preferences.
Rui A. Santos Cruz, Mário Serafim Nunes, Leandro Menezes, and João Domingues
Springer Science and Business Media LLC
This paper describes the development, implementation and evaluation of a SIP based IPTV architecture with a new dynamic QoS adaptation method and signaling structure. The implemented QoS adaptation method allows dynamic updates of session parameters, maximizing the QoE and turning the solution suitable for live multimedia streaming, independently of the cast mode (unicast or multicast). The new SIP signaling structure, for session and media control, was developed following an All-SIP approach and a hybrid SIP+RTSP approach, both suited for an IMS environment, in order to compare the system behavior and performance using either approach. The details of both the IPTV Application Server and the IPTV Client prototypical implementations are described, as well as the results of field tests carried out across different Fixed and Mobile access networks for each of the signaling structures. The proposed IPTV architecture revealed to be suitable for scalable converged networks, due to its flexible multimedia delivery of personalized streams over a variety of network infrastructures, namely, Mobile radio networks.
Hugo Santos, Rui Santos Cruz, and Mário Serafim Nunes
Springer Berlin Heidelberg
This paper presents a novel hybrid RTSP, SIP and HTTP solution for providing converged WebTV services with automatic Rate Adaptation of multimedia content. The prototypical solution, being developed under the scope of the My-eDirector 2012 european project, was deployed in a high-bandwidth LAN and some preliminary tests were performed.
Rui Santos Cruz, Mário Serafim Nunes, and João Espadanal Gonçalves
Springer Berlin Heidelberg
This paper presents a HTTP based multimedia content streaming architecture able to provide large scale WebTV services to end users connected over several access network technologies. The architecture features smooth Rate Adaptation, context Personalization information (Channel Suggestions), fast program channel switching, Network Portability (Vertical Handover) and Terminal Portability capabilities. The prototypical solution is being developed under the scope of the My-eDirector 2012 european project.
Joao Espadanal Goncalves, Rui Santos Cruz, and Mario Serafim Nunes
IEEE
This paper presents the design of a HTTP Adaptive Streaming WebTV Client, featuring smooth media Rate Adaptation, context Personalization, fast program channel switching and Terminal/Network Portability capabilities. The QoS-Awareness during streaming is achieved dynamically by a regulating technique that takes into account network conditions, user's device capabilities and the context of viewing. By dynamically optimizing the video quality experienced by the user, the solution provides an excellent streaming application and protocol for heterogeneous network environments.
Rui Santos Cruz, Mario Serafim Nunes, Charalampos Z. Patrikakis, and Nikolaos C. Papaoulakis
IEEE
This paper presents the design of a platform for distribution of multimedia content streams supported through innovative techniques, both in terms of media encoding and media distribution. The platform architecture accommodates the use of scalable media coding techniques, including both standard and state of the art research methods (wavelets, multiple description coding), combined with new transport and realtime streaming protocols deployed over peer-to-peer networks. Furthermore, discovery of media resources and selection of peer nodes takes into account social networking related information, as this is available in user communities over the Internet. The design of the platform is taking place in the context of the European FP7 project SARACEN.