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Social Network Analysis for Information Flow in Disconnected Delay-Tolerant MANETs
"... Abstract—Message delivery in sparse mobile ad hoc networks (MANETs) is difficult due to the fact that the network graph is rarely (if ever) connected. A key challenge is to find a route that can provide good delivery performance and low end-to-end delay in a disconnected network graph where nodes ma ..."
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Abstract—Message delivery in sparse mobile ad hoc networks (MANETs) is difficult due to the fact that the network graph is rarely (if ever) connected. A key challenge is to find a route that can provide good delivery performance and low end-to-end delay in a disconnected network graph where nodes may move freely. We cast this challenge as an information flow problem in a social network. This paper presents social network analysis metrics that may be used to support a novel and practical forwarding solution to provide efficient message delivery in disconnected delay-tolerant MANETs. These metrics are based on social analysis of a node’s past interactions and consists of three locally evaluated components: a node’s “betweenness ” centrality (calculated using ego networks), a node’s social “similarity ” to the destination node, and a node’s tie strength relationship with the destination node. We present simulations using three real trace data sets to demonstrate that by combining these metrics delivery performance may be achieved close to Epidemic Routing but with significantly reduced overhead. Additionally, we show improved performance when compared to PRoPHET Routing. Index Terms—Delay- and disruption-tolerant networks, MANETs, sparse networks, ego networks, social network analysis.
Bluetooth and Sensor Networks: A Reality Check
, 2003
"... The current generation of sensor nodes rely on commodity components. The choice of the radio is particularly important as it impacts not only energy consumption but also software design (e.g., network self-assembly, multihop routing and in-network processing). Bluetooth is one of the most popular co ..."
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Cited by 54 (1 self)
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The current generation of sensor nodes rely on commodity components. The choice of the radio is particularly important as it impacts not only energy consumption but also software design (e.g., network self-assembly, multihop routing and in-network processing). Bluetooth is one of the most popular commodity radios for wireless devices. As a representative of the frequency hopping spread spectrum radios, it is a natural alternative to broadcast radios in the context of sensor networks. The question is whether Bluetooth can be a viable alternative in practice. In this paper, we report our experience using Bluetooth for the sensor network regime. We describe our tiny Bluetooth stack that allows TinyOS applications to run on Bluetooth-based sensor nodes, we present a multihop network assembly procedure that leverages Bluetooth's device discovery protocol, and we discuss how Bluetooth favorably impacts in-network query processing. Our results show that despite obvious limitations the Bluetooth sensor nodes we studied exhibit interesting properties, such as a good energy per bit sent ratio. This reality check underlies the limitations and some promises of Bluetooth for the sensor network regime.
Partitioning based mobile element scheduling in wireless sensor networks
- IN. PROC. SECOND ANNUAL IEEE CONFERENCE ON SENSOR AND AD HOC COMMUNICATIONS AND NETWORKS (SECON
, 2005
"... In recent studies, using mobile elements (MEs) as mechanical carriers of data has been shown to be an effective way of prolonging sensor network life time and relaying information in partitioned networks. As the data generation rates of sensors may vary, some sensors need to be visited more frequent ..."
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Cited by 35 (0 self)
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In recent studies, using mobile elements (MEs) as mechanical carriers of data has been shown to be an effective way of prolonging sensor network life time and relaying information in partitioned networks. As the data generation rates of sensors may vary, some sensors need to be visited more frequently than others. In this paper, a partitioning-based algorithm is presented that schedules the movements of MEs in a sensor network such that there is no data loss due to buffer overflow. Simulation results show that the proposed Partitioning Based Scheduling (PBS) algorithm performs well in terms of reducing the minimum required ME speed to prevent data loss, providing high predictability in inter-visit durations, and minimizing the data loss rate for the cases when the ME is constrained to move slower than the minimum required ME speed.
Personal Servers as Digital Keys
- In Proc. 2nd IEEE International Conference of Pervasive Computing and Communications
, 2004
"... Personal servers are an attractive concept: People carry around a device that takes care of computing, storage and communication on their behalf in a pervasive computing environment. So far personal servers have mainly been considered for accessing personal information. In this paper, we consider pe ..."
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Cited by 22 (0 self)
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Personal servers are an attractive concept: People carry around a device that takes care of computing, storage and communication on their behalf in a pervasive computing environment. So far personal servers have mainly been considered for accessing personal information. In this paper, we consider personal servers in the context of a digital key system. Digital keys are an interesting alternative to physical keys for mail or good delivery companies whose employees access tens of private buildings every day. In this paper, we present a digital key system tailored for the current incarnation of personal servers, i.e., a Bluetooth-enabled mobile phone. We describe how to use Bluetooth for this application, we present a simple authentication protocol and we provide a detailled analysis of response time and energy consumption on the mobile phone.
On a Routing Problem Within Probabilistic Graphs and its Application to Intermittently Connected Networks. In
- INFOCOM’07,
, 2007
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Robotic data mules for collecting data over sparse sensor fields
- Journal of Field Robotics
, 2011
"... We present a robotic system for collecting data from wireless devices dispersed across a large environment. In such applications, deploying a network of stationary wireless sensors may be infeasible because many relay nodes must be deployed to ensure connectivity. Instead, our system utilizes robots ..."
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Cited by 17 (4 self)
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We present a robotic system for collecting data from wireless devices dispersed across a large environment. In such applications, deploying a network of stationary wireless sensors may be infeasible because many relay nodes must be deployed to ensure connectivity. Instead, our system utilizes robots which act as data mules and gather the data from wireless sensor network nodes. We address the problem of planning paths of multiple robots so as to collect the data from all sensors in the least amount of time. In this new routing problem, which we call the Data Gathering Problem (DGP), the total download time depends on not only the robots ’ travel time but also the time to download data from a sensor, and the number of sensors assigned to the robot. We start with a special case of DGP where the robots ’ motion is restricted to a curve which contains the base station at one end. For this version, we present an optimal algorithm. ∗A preliminary version of this paper appeared in IROS’09 (Bhadauria and Isler, 2009). Next, we study the 2D version, and present a constant factor approximation algorithm for DGP on the plane. Finally, we present field experiments in which an autonomous robotic data mule collects data from the nodes of a wireless sensor network deployed over a large field. 1
Fundamental mobility properties for realistic performance analysis of intermittently connected mobile networks
, 2007
"... Traditional mobile ad hoc routing protocols fail to deliver any data in Intermittently Connected Mobile Ad Hoc Networks (ICMN’s) because of the absence of complete end-to-end paths in these networks. To overcome this issue, researchers have proposed to use node mobility to carry data around the net ..."
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Cited by 13 (3 self)
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Traditional mobile ad hoc routing protocols fail to deliver any data in Intermittently Connected Mobile Ad Hoc Networks (ICMN’s) because of the absence of complete end-to-end paths in these networks. To overcome this issue, researchers have proposed to use node mobility to carry data around the network. These schemes are referred to as mobility-assisted routing schemes. A mobility-assisted routing scheme forwards data only when appropriate relays meet each other. The time it takes for them to first meet each other is referred to as the meeting time. The time duration they remain in contact with each other is called the contact time. If they fail to exchange the packet during the contact time (due to contention in the network), then they have to wait till they meet each other again. This time duration is referred to as the inter meeting time. A realistic performance analysis of any mobility-assisted routing scheme requires a knowledge of the statistics of these three quantities. These quantities vary largely depending on the mobility model at hand. This paper studies these three quantities for the three most popularly used mobility models: random direction, random waypoint and random walk models. Hence, this work allows for a realistic performance analysis of any routing scheme under any of these three mobility models.
Multiple-copy Routing in Intermittently Connected Mobile Networks
, 2004
"... Intermittently connected mobile networks are wireless networks where most of the time there does not exist a complete path from the source to the destination. There are many real networks that fall into this paradigm, for example, wildlife tracking sensor networks, military networks, inter-planetary ..."
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Cited by 7 (4 self)
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Intermittently connected mobile networks are wireless networks where most of the time there does not exist a complete path from the source to the destination. There are many real networks that fall into this paradigm, for example, wildlife tracking sensor networks, military networks, inter-planetary networks, etc. In this context, conventional routing schemes would fail. To deal with such networks researchers have suggested to use flooding-based routing schemes. While flooding-based schemes have a high probability of delivery, they waste a lot of energy and suffer from severe contention which can significantly degrade their performance. With this in mind, we introduce a new routing scheme, called Spray and Wait, that “sprays ” a number of copies into the network, and then “waits ” till one of these nodes meets the destination. We compare this scheme to a number of different routing algorithms including an oracle-based optimal algorithm that minimizes average message delivery delay while using the lowest possible number of transmissions. Theory and simulations show that Spray and Wait has a number of desirable properties: it is very simple to implement, it is highly scalable, it performs close to the optimal scheme, and quite surprisingly, it outperforms all existing schemes with respect to both average message delivery delay and number of transmissions per message delivered.
Efficient Data Collection from Wireless Nodes under the Two-Ring Communication Model
, 2012
"... We introduce a new geometric robot routing problem which arises in data muling applications where a mobile robot is charged with collecting data from stationary sensors. The objective is to compute the robot’s trajectory and download sequence so as to minimize the time to collect the data from all s ..."
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Cited by 7 (3 self)
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We introduce a new geometric robot routing problem which arises in data muling applications where a mobile robot is charged with collecting data from stationary sensors. The objective is to compute the robot’s trajectory and download sequence so as to minimize the time to collect the data from all sensors. The total data collection time has two components: the robot’s travel time and the download time. The time to download data from a sensor s is a function of the locations of the robot and s: If the robot is a distance rin away from s, it can download the sensor’s data in Tin units of time. If the distance is greater than rin but less than rout, the download time is Tout> Tin. Otherwise, the robot can not download the data from s. Here, rin, rout, Tin and Tout are input parameters. We refer to this model, which is based on recently developed experimental models for sensor network deployments, as the two ring model, and the problem of downloading data from a given set of sensors in minimum amount of time under this model as the Two-Ring Tour (TRT) problem. We present approximation algorithms for the general case which uses solutions to the Traveling Salesperson with Neighborhoods (TSPN) Problem as subroutines. We also present efficient solutions to special but practically important versions of the problem such as grid-based and sparse deployments. The approach is validated in outdoor experiments. 1
