Improving vehicular delay-tolerant network performance with relay nodes

“Copyright © [2009] IEEE. Reprinted from Next Generation Internet Network. NGI '09). ISBN:978-1-4244-4244-7. This material is posted here with permission of the IEEE. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.”Vehicular Delay-Tolerant Networking (VDTN) is an extension of the Delay-Tolerant Network (DTN) architecture concept to transit networks. VDTN architecture handles non-real time applications, exploiting vehicles to enable connectivity under unreliable scenarios with unstable links and where an end-to-end path may not exist. Intuitively, the use of stationary store-and-forward devices (relay nodes) located at crossroads where vehicles meet them and should improve the message delivery probability. In this paper, we analyze the influence of the number of relay nodes, in urban scenarios with different numbers of vehicles. It was shown that relay nodes significantly improve the message delivery probability on studied DTN routing protocols.Part of this work has been supported by the Instituto de Telecomunicações, Next Generation Networks and Applications Group, Portugal, in the framework of the Project VDTN@Lab, and by the Euro-NF Network of Excellence of Seven Framework Programme of EU

Evaluating the impact of storage capacity constraints on vehicular delay-tolerant networks

“Copyright © [2009] IEEE. Reprinted from Second International Conference on Communication Theory Reliability, and Quality of Service, 2009. CTRQ'09. ISBN:978-1-4244-4423-6. This material is posted here with permission of the IEEE. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.”Vehicular Delay-Tolerant Network (VDTN) was proposed as a particular application of a mobile Delay-Tolerant Network (DTN), where vehicles act as the communication infrastructure for the network, relaying messages between the network nodes. In this paper, we consider the use of a VDTN to provide low-cost asynchronous communication between sparse populations spread over a remote vast region. We analyze the influence of the VDTN network node’s storage capacity (buffer size), on the efficiency of four DTN routing protocols, in terms of message delivery probability. Our scenarios show that the routing protocols message replication strategies react differently to the increase of buffer size in specific network nodes. Epidemic and MaxProp protocols benefit from the increase of the storage capacity on all network nodes. Spray and Wait protocol only takes advantage on the increase of the vehicle’s buffer capacity. We expect that this paper will provide a deep understanding of the implications of storage constraints over the performance of a VDTN, leading to insights for future routing algorithm and buffer management theoretic studies and protocol design.Part of this work has been supported by the Instituto de Telecomunicações, Next Generation Networks and Applications Group, Portugal, in the framework of the Project VDTN@Lab, and by the Euro-NF Network of Excellence of Seven Framework Programme of EU

Performance analysis of scheduling and dropping policies in vehicular delay-tolerant networks

Vehicular Delay-Tolerant Networking (VDTN) was proposed as a new variant of a delay/disruptive-tolerant network, designed for vehicular networks. These networks are subject to several limitations including short contact durations, connectivity disruptions, network partitions, intermittent connectivity, and long delays. To address these connectivity issues, an asynchronous, store-carry-and-forward paradigm is combined with opportunistic bundle replication, to achieve multi-hop data delivery. Since VDTN networks are resource-constrained, for example in terms of communication bandwidth and storage capacity, a key challenge is to provide scheduling and dropping policies that can improve the overall performance of the network. This paper investigates the efficiency and tradeoffs of several scheduling and dropping policies enforced in a Spray and Wait routing scheme. It has been observed that these policies should give preferential treatment to less replicated bundles for a better network performance in terms of delivery ratio and average delivery delay.Part of this work has been supported by Instituto de Telecomunicações, Next Generation Networks and Applications Group (NetGNA), Portugal, in the framework of the Project VDTN@Lab, and by the Euro-NF Network of Excellence of the Seventh Framework Programme of EU, in the framework of the Project VDTN

A novel intra-body sensor for vaginal temperature monitoring

Over the years some medical studies have tried to better understand the internal behavior of human beings. Many researchers in this domain have been striving to find relationships between intra-vaginal temperature and certain female health conditions, such as ovulation and fertile period since woman’s intra-vaginal temperature is one of the body parameters most preferred in such studies. However, due to lack of a appropriate technology, medical research devoted to studying correlations of such body parameters with certain womans’ body phenomena could not obtain better results. This article presents the design and implementation of a novel intra-body sensor for acquisition and monitoring of intra-vaginal temperatures. This novel intra-body sensor provides data collection that is used for studying the relation between temperature variations and female health conditions, such as anticipation and monitoring of the ovulation period, detection of pregnancy contractions, preterm labor prevention, etc.. The motivation for this work focuses on the development of this new intra-body sensor that will represent a major step in medical technology. The novel sensor was tested and validated on hospitalized women as well as normal healthy women. Finally our medical team has attested to the accuracy, usability and performance of this novel intra-body sensor

Scheduling and drop policies for traffic differentiation on vehicular delay-tolerant networks

“Copyright © [2009] IEEE. Reprinted from 17th International Conference on Software, Telecommunications & Computer Networks, 2009. SoftCOM 2009.ISBN:978-1-4244-4973-6. This material is posted here with permission of the IEEE. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.”Vehicular Delay-Tolerant Networks (VDTNs) are a promising technology for vehicular communications, creating application scenarios that enable non-real time services with diverse performance requirements. Because of scarce network resources (e.g. bandwidth and storage capacity) and node’s short contact durations, the underlying VDTN network infrastructure must be capable of prioritizing traffic. This paper investigates several scheduling and drop policies, which can be used to implement traffic differentiation. Priority Greedy, Round Robin, and Time Threshold scheduling polices are proposed. In terms of drop policy, the message with the lowest priority and the lowest remaining time-to-live is discarded first. We evaluate their efficiency and tradeoffs, through simulation. The results presented in this paper can be used as a starting point for further studies in this research field, and give helpful guidelines for future VDTN protocol design.Part of this work has been supported by Instituto de Telecomunicações, Next Generation Networks and Applications Group (NetGNA), Portugal, in the framework of the Project VDTN@Lab, and by the Euro-NF Network of Excellence of the Seventh Framework Programme of EU

Impact analysis of the shortest path movement model on routing strategies for VDTNs in a rural region

Vehicular Delay-Tolerant Network (VDTN) appears as a particular application of the Delay-Tolerant Network (DTN) concept to transit networks. In this paper we analyze the use of a VDTN to provide asynchronous Internet access on a rural remote region scenario. Through simulation we evaluate the impact of a shortest path based movement model on the performance of four DTN routing protocols in respect to message delivery probability and message average delay.Part of this work has been supported by the Instituto de Telecomunicações, Portugal, in the framework of the Project VDTN@Lab, and by the Euro-NF Network of Excellence of Seven Framework Programme of EU

VDTNsim: a simulation tool for vehicular delay-tolerant networks

“Copyright © [2010] IEEE. Reprinted from 15th IEEE International Workshop on Computer-Aided Modeling Analysis and Design of Communication Links and Networks.(IEEE CAMAD 2010) ISBN:978-1-4244-7634-3. This material is posted here with permission of the IEEE. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.”Developing an adequate network architecture for supporting data communications in vehicular networks is critical to overcome the challenges caused by highly dynamic network topology, connectivity disruption, and intermittent connectivity issues. Among several approaches available in the literature proposed to address these problems, vehicular delay-tolerant networking (VDTN) architecture appears as a recent and innovative solution that integrates the concepts of end-to-end, asynchronous, and variable-length bundle oriented communication; Internet protocol over VDTN; and out-of-band signaling. VDTN architecture, protocols and services are in a fairly early stage of development. Therefore, simulation appears as an important tool providing a highly flexible, low-cost, and fast answer for research questions, and furnishes important inputs for exploring through prototyping. This paper presents and describes the proposal and construction of a simulation tool for VDTN networks, called VDTNsim.Part of this work has been supported by Instituto de Telecomunicações, Next Generation Networks and Applications Group (NetGNA), Portugal, in the framework of the Project VDTN@Lab, and by the Euro-NF Network of Excellence of the Seventh Framework Programme of EU, in the framework of the Specific Joint Research Project VDTN

A novel intra-body sensor for vaginal temperature monitoring

Over the years some medical studies have tried to better understand the internal behavior of human beings. Many researchers in this domain have been striving to find relationships between intra-vaginal temperature and certain female health conditions, such as ovulation and fertile period since woman’s intra-vaginal temperature is one of the body parameters most preferred in such studies. However, due to lack of a appropriate technology, medical research devoted to studying correlations of such body parameters with certain womans’ body phenomena could not obtain better results. This article presents the design and implementation of a novel intra-body sensor for acquisition and monitoring of intra-vaginal temperatures. This novel intra-body sensor provides data collection that is used for studying the relation between temperature variations and female health conditions, such as anticipation and monitoring of the ovulation period, detection of pregnancy contractions, preterm labor prevention, etc.. The motivation for this work focuses on the development of this new intra-body sensor that will represent a major step in medical technology. The novel sensor was tested and validated on hospitalized women as well as normal healthy women. Finally our medical team has attested to the accuracy, usability and performance of this novel intra-body sensor

G-Jsim: A GUI tool for wireless sensor networks simulation under J-Sim

“Copyright © [2008] IEEE. Reprinted from 12th Annual IEEE International Symposium on Consumer Electronics (ISCE 2008). ISBN:978-1-4244-2422-1. This material is posted here with permission of the IEEE. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.”A Wireless Sensor Network is composed of up to thousands of smart sensing nodes with processing unit and memory, sensing unit and wireless communication capabilities. Wireless Sensor Networks application spans from the military applications into almost every field we can think of. Several simulation tools are readily available, among them the J-Sim, a java-based simulator with growing interest by research and network developers alike. We propose to enhance J-Sim functionality with a Guided User Interface for Wireless Sensor Networks that dramatically increases the user-friendliness of the simulator. Also, we provide a free download web page for everyone to benefit