Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2009
Telecommunications companies are investing in ways to offer its customers triple-play services an... more Telecommunications companies are investing in ways to offer its customers triple-play services and some of them are starting to think about integration with mobile services. This means that there is a convergence at the network for IP (Internet Protocol), to offer the different services. In an ALL-IP network, personalized and interactive services can be provided very easily. IPTV is the technology responsible for this convergence and this technology will bring a variety of new business opportunities. This paper proposes a study of the IPTV world, focusing on network and system architectures, video codecs, network protocols, services and quality assurance service in IPTV. Based on this study, a new framework for Personal TV was developed. This new system is designed primarily to provide new personalized services to the user. In the architecture of this framework there are three main elements: Customers, Aggregators and Producers. The most important element is the aggregator that provides all video contents from the producers to its clients. The Client has the ability to create his own channel that is sent to the network through its aggregator, to create customized channels that can be viewed by other customers and other features. The architecture designed and developed is based on new and studied concepts. It was tested to prove its viability, to assess its performance and to draw conclusions about its scalability, based on functional tests, compatibility tests and performance tests.
This paper proposes a new high throughput low coupling multipath routing protocol for Wireless Mu... more This paper proposes a new high throughput low coupling multipath routing protocol for Wireless Multimedia Sensor Networks and describes its design, implementation and performance analysis. Our approach attempts to improve throughput by means of the Expected Transmission Count (ETX) metric and chooses routes with minimum interference among them by using a modified version of the Con-elation Factor (CF). The ETX metric represents the expected total number of transmissions (including retransmissions) required to successfully deliver a packet to the destination node. ETX allows finding high-throughput paths on a multi-hop wireless network. ETX incorporates the effects of link loss ratios, asymmetry in the loss ratios between the two directions of each link, and the interference among the successive links of a path. The radio interference when using multiple simultaneous routes can greatly degrade the network performance. The CF is determined using neighbor information, allowing to find ...
Networks with frequent and long duration partitions prevent common Internet protocols from workin... more Networks with frequent and long duration partitions prevent common Internet protocols from working successfully. For protocols to work properly in these Delay/Disruption Tolerant Networks (DTNs), a new protocol layer was proposed that acts on top of the transport layer for the end-to-end exchange of messages (called bundles) taking advantage of scheduled, predicted, opportunistic or permanent connectivity. In this paper, we
This article presents the European FP7 Network of Excellence "Euro-NF" (Networks of the Future) a... more This article presents the European FP7 Network of Excellence "Euro-NF" (Networks of the Future) and reviews its set of activities. Specific attention is paid to the concept of Specific Joint Research Projects (SJRP), a series of small but focused projects, integrating at least three Euro-NF partners and targeting joint seminal work, publications as well as full-size follow-up projects. Further to the description of the SJRP concept, a set of three selected SJRP from different areas are presented in detail with respect to motivation, goal, contents, results, and impact. 2.2 Joint Research Activities "With the aim of integrating research activities performed by its partners, Euro-NF concentrates the JRA on mapping the scientific developments with the future networking needs" [2]. The JRA are split into three complementary areas:
In this paper a new multi-objective approach for the routing problem in Wireless Multimedia Senso... more In this paper a new multi-objective approach for the routing problem in Wireless Multimedia Sensor Networks (WMSNs) is proposed. It takes into account Quality of Service (QoS) requirements such as delay and the Expected Transmission Count (ETX). Classical approximations optimize a single objective or QoS parameter, not taking into account the conflicting nature of these parameters which leads to sub-optimal solutions. The case studies applying the proposed approach shows clear improvements on the QoS routing solutions. For example, in terms of delay, the approximate mean improvement ratios obtained for scenarios 1 and 2 were of 15 and 28 times, respectively.
Proceedings of the 8th Euro-NF Conference on Next Generation Internet NGI 2012, 2012
This paper presents an overview of a Wireless Sensor and Actuator Network (WSAN) used to monitor ... more This paper presents an overview of a Wireless Sensor and Actuator Network (WSAN) used to monitor an electrical power grid distribution infrastructure. The WSAN employs appropriate sensors to monitor key grid components, integrating both safety and security services, which improve the grid distribution dependability. The supported applications include, among others, video surveillance of remote secondary substations, which imposes special requirements from the point of view of quality of service and reliability. The paper presents the hardware and software architecture of the system together with performance results.
This paper presents a survey on transport and routing protocols for wireless sensor networks (WSN... more This paper presents a survey on transport and routing protocols for wireless sensor networks (WSN). Research challenges regarding the problem of end-to-end reliability are addressed in particular.
The guaranteed delivery of critical data is an essential requirement in most Wireless Sensor Netw... more The guaranteed delivery of critical data is an essential requirement in most Wireless Sensor Network (WSN) applications. The paucity of energy, communication, processing and storage resources in each WSN node causes the TCP transport model (widely used in broadband networks) to be inefficient in WSNs, a reason why new WSN-specific reliable transport protocols have been proposed in the past few years. This paper presents one of these protocols, the Distributed Transport for Sensor Networks (DTSN). DTSN is able to efficiently support unicast communications in WSNs due to its capabilities to tightly control the amount of signaling and retransmission overhead. The basic loss recovery algorithm is based on Selective Repeat ARQ, employing both positive and negative acknowledgements. Caching at intermediate nodes is used to avoid the inefficiency typical of the strictly end-to-end transport reliability commonly assumed in broadband networks. DTSN is currently implemented in TinyOS. Preliminary simulation results using this code show that DTSN is quite efficient providing block oriented reliability, while the caching mechanism employed in DTSN decreases packet delay for more than one hop.
In delay-tolerant mobile cyber-physical systems, mobile sensing and computing devices interact fo... more In delay-tolerant mobile cyber-physical systems, mobile sensing and computing devices interact following the delay tolerant network (DTN) routing paradigm, storing (or buffering) messages and forwarding them to other nodes until they reach their target, which can be a server or a cloud application, for further processing or storage. Cyber-security threats and the selforganizing nature of DTN environments pose a set of security challenges to the design of delaytolerant mobile cyber-physical applications. On the one hand, the increase in the interaction between the physical and cyber-systems increases the exposure of physical systems to cyber systems' security threats. On the other hand, finding a suitable node to forward messages may incur in the consumption of nodes' limited resources. Trust establishment and the fairness of contributions among nodes also raise additional concerns in such environments. In this chapter, a comprehensive overview of security mechanisms in delay-tolerant mobile cyber-physical applications is presented. Topics like authentication, confidentiality, integrity, availability, privacy, trust, and cooperation enforcement are analyzed.
This paper presents a survey on transport and routing protocols for wireless sensor networks (WSN... more This paper presents a survey on transport and routing protocols for wireless sensor networks (WSN). Research challenges regarding the problem of end-to-end reliability are addressed in particular.
The guaranteed delivery of critical data is an essential requirement in most Wireless Sensor Netw... more The guaranteed delivery of critical data is an essential requirement in most Wireless Sensor Network (WSN) applications. The paucity of energy, communication, processing and storage resources in each WSN node causes the TCP transport model (widely used in broadband networks) to be inefficient in WSNs, a reason why new WSN-specific reliable transport protocols have been proposed in the past few years. This paper presents one of these protocols, the Distributed Transport for Sensor Networks (DTSN). DTSN is able to efficiently support unicast communications in WSNs due to its capabilities to tightly control the amount of signaling and retransmission overhead. The basic loss recovery algorithm is based on Selective Repeat ARQ, employing both positive and negative acknowledgements. Caching at intermediate nodes is used to avoid the inefficiency typical of the strictly end-to-end transport reliability commonly assumed in broadband networks. DTSN is currently implemented in TinyOS. Preliminary simulation results using this code show that DTSN is quite efficient providing block oriented reliability, while the caching mechanism employed in DTSN decreases packet delay for more than one hop.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2009
Telecommunications companies are investing in ways to offer its customers triple-play services an... more Telecommunications companies are investing in ways to offer its customers triple-play services and some of them are starting to think about integration with mobile services. This means that there is a convergence at the network for IP (Internet Protocol), to offer the different services. In an ALL-IP network, personalized and interactive services can be provided very easily. IPTV is the technology responsible for this convergence and this technology will bring a variety of new business opportunities. This paper proposes a study of the IPTV world, focusing on network and system architectures, video codecs, network protocols, services and quality assurance service in IPTV. Based on this study, a new framework for Personal TV was developed. This new system is designed primarily to provide new personalized services to the user. In the architecture of this framework there are three main elements: Customers, Aggregators and Producers. The most important element is the aggregator that provides all video contents from the producers to its clients. The Client has the ability to create his own channel that is sent to the network through its aggregator, to create customized channels that can be viewed by other customers and other features. The architecture designed and developed is based on new and studied concepts. It was tested to prove its viability, to assess its performance and to draw conclusions about its scalability, based on functional tests, compatibility tests and performance tests.
This paper proposes a new high throughput low coupling multipath routing protocol for Wireless Mu... more This paper proposes a new high throughput low coupling multipath routing protocol for Wireless Multimedia Sensor Networks and describes its design, implementation and performance analysis. Our approach attempts to improve throughput by means of the Expected Transmission Count (ETX) metric and chooses routes with minimum interference among them by using a modified version of the Con-elation Factor (CF). The ETX metric represents the expected total number of transmissions (including retransmissions) required to successfully deliver a packet to the destination node. ETX allows finding high-throughput paths on a multi-hop wireless network. ETX incorporates the effects of link loss ratios, asymmetry in the loss ratios between the two directions of each link, and the interference among the successive links of a path. The radio interference when using multiple simultaneous routes can greatly degrade the network performance. The CF is determined using neighbor information, allowing to find ...
Networks with frequent and long duration partitions prevent common Internet protocols from workin... more Networks with frequent and long duration partitions prevent common Internet protocols from working successfully. For protocols to work properly in these Delay/Disruption Tolerant Networks (DTNs), a new protocol layer was proposed that acts on top of the transport layer for the end-to-end exchange of messages (called bundles) taking advantage of scheduled, predicted, opportunistic or permanent connectivity. In this paper, we
This article presents the European FP7 Network of Excellence "Euro-NF" (Networks of the Future) a... more This article presents the European FP7 Network of Excellence "Euro-NF" (Networks of the Future) and reviews its set of activities. Specific attention is paid to the concept of Specific Joint Research Projects (SJRP), a series of small but focused projects, integrating at least three Euro-NF partners and targeting joint seminal work, publications as well as full-size follow-up projects. Further to the description of the SJRP concept, a set of three selected SJRP from different areas are presented in detail with respect to motivation, goal, contents, results, and impact. 2.2 Joint Research Activities "With the aim of integrating research activities performed by its partners, Euro-NF concentrates the JRA on mapping the scientific developments with the future networking needs" [2]. The JRA are split into three complementary areas:
In this paper a new multi-objective approach for the routing problem in Wireless Multimedia Senso... more In this paper a new multi-objective approach for the routing problem in Wireless Multimedia Sensor Networks (WMSNs) is proposed. It takes into account Quality of Service (QoS) requirements such as delay and the Expected Transmission Count (ETX). Classical approximations optimize a single objective or QoS parameter, not taking into account the conflicting nature of these parameters which leads to sub-optimal solutions. The case studies applying the proposed approach shows clear improvements on the QoS routing solutions. For example, in terms of delay, the approximate mean improvement ratios obtained for scenarios 1 and 2 were of 15 and 28 times, respectively.
Proceedings of the 8th Euro-NF Conference on Next Generation Internet NGI 2012, 2012
This paper presents an overview of a Wireless Sensor and Actuator Network (WSAN) used to monitor ... more This paper presents an overview of a Wireless Sensor and Actuator Network (WSAN) used to monitor an electrical power grid distribution infrastructure. The WSAN employs appropriate sensors to monitor key grid components, integrating both safety and security services, which improve the grid distribution dependability. The supported applications include, among others, video surveillance of remote secondary substations, which imposes special requirements from the point of view of quality of service and reliability. The paper presents the hardware and software architecture of the system together with performance results.
This paper presents a survey on transport and routing protocols for wireless sensor networks (WSN... more This paper presents a survey on transport and routing protocols for wireless sensor networks (WSN). Research challenges regarding the problem of end-to-end reliability are addressed in particular.
The guaranteed delivery of critical data is an essential requirement in most Wireless Sensor Netw... more The guaranteed delivery of critical data is an essential requirement in most Wireless Sensor Network (WSN) applications. The paucity of energy, communication, processing and storage resources in each WSN node causes the TCP transport model (widely used in broadband networks) to be inefficient in WSNs, a reason why new WSN-specific reliable transport protocols have been proposed in the past few years. This paper presents one of these protocols, the Distributed Transport for Sensor Networks (DTSN). DTSN is able to efficiently support unicast communications in WSNs due to its capabilities to tightly control the amount of signaling and retransmission overhead. The basic loss recovery algorithm is based on Selective Repeat ARQ, employing both positive and negative acknowledgements. Caching at intermediate nodes is used to avoid the inefficiency typical of the strictly end-to-end transport reliability commonly assumed in broadband networks. DTSN is currently implemented in TinyOS. Preliminary simulation results using this code show that DTSN is quite efficient providing block oriented reliability, while the caching mechanism employed in DTSN decreases packet delay for more than one hop.
In delay-tolerant mobile cyber-physical systems, mobile sensing and computing devices interact fo... more In delay-tolerant mobile cyber-physical systems, mobile sensing and computing devices interact following the delay tolerant network (DTN) routing paradigm, storing (or buffering) messages and forwarding them to other nodes until they reach their target, which can be a server or a cloud application, for further processing or storage. Cyber-security threats and the selforganizing nature of DTN environments pose a set of security challenges to the design of delaytolerant mobile cyber-physical applications. On the one hand, the increase in the interaction between the physical and cyber-systems increases the exposure of physical systems to cyber systems' security threats. On the other hand, finding a suitable node to forward messages may incur in the consumption of nodes' limited resources. Trust establishment and the fairness of contributions among nodes also raise additional concerns in such environments. In this chapter, a comprehensive overview of security mechanisms in delay-tolerant mobile cyber-physical applications is presented. Topics like authentication, confidentiality, integrity, availability, privacy, trust, and cooperation enforcement are analyzed.
This paper presents a survey on transport and routing protocols for wireless sensor networks (WSN... more This paper presents a survey on transport and routing protocols for wireless sensor networks (WSN). Research challenges regarding the problem of end-to-end reliability are addressed in particular.
The guaranteed delivery of critical data is an essential requirement in most Wireless Sensor Netw... more The guaranteed delivery of critical data is an essential requirement in most Wireless Sensor Network (WSN) applications. The paucity of energy, communication, processing and storage resources in each WSN node causes the TCP transport model (widely used in broadband networks) to be inefficient in WSNs, a reason why new WSN-specific reliable transport protocols have been proposed in the past few years. This paper presents one of these protocols, the Distributed Transport for Sensor Networks (DTSN). DTSN is able to efficiently support unicast communications in WSNs due to its capabilities to tightly control the amount of signaling and retransmission overhead. The basic loss recovery algorithm is based on Selective Repeat ARQ, employing both positive and negative acknowledgements. Caching at intermediate nodes is used to avoid the inefficiency typical of the strictly end-to-end transport reliability commonly assumed in broadband networks. DTSN is currently implemented in TinyOS. Preliminary simulation results using this code show that DTSN is quite efficient providing block oriented reliability, while the caching mechanism employed in DTSN decreases packet delay for more than one hop.
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Papers by Paulo Pereira