Nirupama Bulusu - Academia.edu (original) (raw)

Papers by Nirupama Bulusu

Ad hoc networks, Nov 1, 2006

In this paper, we consider the problem of network deployment in hybrid sensor networks, consistin... more In this paper, we consider the problem of network deployment in hybrid sensor networks, consisting of both resource-rich and resource-impoverished sensor devices. The resource-rich devices, called micro-servers, are more expensive but have significantly greater bandwidth and energy capabilities compared to the low-cost, lowpowered sensors. Such hybrid sensor networks have the potential to support the higher bandwidth communications of broadband sensor networking applications, as

ACM Transactions in Embedded Computing Systems, Oct 6, 2014

Crowd-sourced mobile embedded systems allow people to contribute sensor data, for critical applic... more Crowd-sourced mobile embedded systems allow people to contribute sensor data, for critical applications, including transportation, emergency response and eHealth. Data integrity becomes imperative as malicious participants can launch software and Sybil attacks modifying the sensing platform and data. To address these attacks, we develop (i) a Trusted Sensing Peripheral (TSP) enabling collection of high-integrity raw or aggregated data, and participation in applications requiring additional modalities; and (ii) a Secure Tasking and Aggregation Protocol (STAP) enabling aggregation of TSPs trusted readings by untrusted intermediaries, while efficiently detecting fabricators. Evaluations demonstrate that TSP and STAP are practical and energy-efficient.

Center for Embedded Network Sensing, 2000

Instrumenting the physical world through large networks of wireless sensor nodes, particularly fo... more Instrumenting the physical world through large networks of wireless sensor nodes, particularly for applications like environmental monitoring of water and soil, requires that these nodes be very small, light, untethered and unobtrusive. The problem of localization, i.e., determining where a given node is physically located in a network is a challenging one, and yet extremely crucial for many of these applications. Practical considerations such as the small size, form factor, cost and power constraints of nodes preclude the reliance on GPS (Global Positioning System) on all nodes in these networks. In this paper, we review localization techniques and evaluate the effectiveness of a very simple connectivity-metric method for localization in outdoor environments that makes use of the inherent radio-frequency (RF) communications capabilities of these devices. A fixed number of reference points in the network with overlapping regions of coverage transmit periodic beacon signals. Nodes use a simple connectivity metric, that is more robust to environmental vagaries, to infer proximity to a given subset of these reference points. Nodes localize themselves to the centroid of their proximate reference points. The accuracy of localization is then dependent on the separation distance between two adjacent reference points and the transmission range of these reference points. Initial experimental results show that the accuracy for 90% of our data points is within one-third of the separation distance. However future work is needed to extend the technique to more cluttered environments. Keywords-localization, location, radio-frequency wireless network. 1 We borrow the term localization from robotics, where it refers to the problem of determining the position of a mobile robot in some coordinate system.

Wireless sensor networks are poised to become an ubiquitous part of the computing landscape. We a... more Wireless sensor networks are poised to become an ubiquitous part of the computing landscape. We are developing and class-testing sensor network lab exercises. The goal is to enable undergraduate students to learn sensor network concepts in a hands-on manner, and build sensor networking applications. This demonstration of tracking a light contour using a network of SunSPOT devices showcases a project completed by students in less than two weeks at the end of our sensor network course.

Spatial localization or the ability to locate nodes is an important building block for next gener... more Spatial localization or the ability to locate nodes is an important building block for next generation pervasive computing systems, but a formidable challenge, particularly, for very small hardware and energy constrained devices, for noisy, unpredictable environments and for very large ad hoc deployed and networked systems. In this paper, we describe, validate and evaluate in real environments a very simple self localization methodology for RF-based devices based only on RF-connectivity constraints to a set of beacons (known nodes), applicable outdoors. Beacon placement has a significant impact on the localization quality in these systems. To self-configure and adapt the localization in noisy environments with unpredictable radio propagation vagaries, we introduce the novel concept of adaptive beacon placement. We propose several novel and density adaptive algorithms for beacon placement and demonstrate their effectiveness through evaluations. We also outline an approach in which beacons leverage a software controllable variable transmit power capability to further improve localization granularity. These combined features allow a localization system that is scalable and ad hoc deployable, long-lived and robust to noisy environments. The unique aspect of our localization approach is our emphasis on adaptive selfconfiguration.

USENIX conference on Hot topics in security, Aug 11, 2009

Grassroots Participatory Sensing empowers people to collect and share sensor data using mobile de... more Grassroots Participatory Sensing empowers people to collect and share sensor data using mobile devices across many applications, spanning intelligent transportation, air quality monitoring and social networking. In this paper, we argue that the very openness of such a system makes it vulnerable to abuse by malicious users who may poison the information, collude to fabricate information, or launch Sybils to distort that information. We propose and implement a novel trusted platform module (TPM), or angel based system that addresses the problem of providing sensor data integrity. The key idea is to provide a trusted platform within each sensor device to attest the integrity of sensor readings. We argue that this localizes integrity checking to the device, rather than relying on corroboration, making the system not only simpler, but also resistant to collusion and data poisoning. A "burnedin" private key in the TPM prevents users from launching Sybils. We also make the case for content protection and access control mechanisms that enable users to publish sensor data streams to selected groups of people and address it using broadcast encryption techniques.

Localization of small wireless sensor devices, with the deployment of the minimal infrastructure ... more Localization of small wireless sensor devices, with the deployment of the minimal infrastructure or hardware, has been the topic of significant research over the past few years. We have developed the Robust Extended Kalman Filter (REKF) localization system[1], which enables a mobile, data gathering robot to localize static sensor devices, by combining the RSSI data received from the motes, with estimates of its trajectory. The REKF localization system is particularly well suited to delay-tolerant sensor networks, where node positions need not be known in real time. We have observed accuracies ranging from approximately 30cm to 1m in practice.

In this paper, we provide a basic solution for online compression of data streams using error-bou... more In this paper, we provide a basic solution for online compression of data streams using error-bounded piecewiselinear approximation (PLA). We compare this method to the optimal (but offline) solution. Our current work in progress is developing an online PLA method that meets the same optimality constraints as the offline method. Also, the vertices of the constructed approximations are subsets of the sampled data points, which we believe to be a benefit in many scenarios.

Networked drones have the potential to transform various applications domains; yet their adoption... more Networked drones have the potential to transform various applications domains; yet their adoption particularly in indoor and forest environments has been stymied by the lack of accurate maps and autonomous navigation abilities in the absence of GPS, the lack of highly reliable, energy-efficient wireless communications, and the challenges of visually inferring and understanding an environment with resource-limited individual drones. We advocate a novel vision for the research community in the development of distributed, localized algorithms that enable the networked drones to dynamically coordinate to perform adaptive beam forming to achieve high capacity directional aerial communications, and collaborative machine learning to simultaneously localize, map and visually infer the challenging environment, even when individual drones are resource-limited in terms of computation and communication due to payload restrictions. CCS CONCEPTS • Networks → Location based services; Cross-layer protocols; • Computing methodologies → Ensemble methods.

As sensor networking technologies continue to develop, the notion of adding large-scale mobility ... more As sensor networking technologies continue to develop, the notion of adding large-scale mobility into sensor networks is becoming feasible by crowd-sourcing data collection to personal mobile devices. However, tasking such networks at fine granularity becomes problematic because the sensors are heterogeneous, owned by the crowd and not the network operators. In this paper, we present Zoom, a multi-resolution tasking framework for crowdsourced geo-spatial sensor networks. Zoom allows users to define arbitrary sensor groupings over heterogeneous, unstructured and mobile networks and assign different sensing tasks to each group. The key idea is the separation of the task information (what task a particular sensor should perform) from the task implementation (code). Zoom consists of (i) a map, an overlay on top of a geographic region, to represent both the sensor groups and the task information, and (ii) adaptive encoding of the map at multiple resolutions and region-of-interest cropping for resource-constrained devices, allowing sensors to zoom in quickly to a specific region to determine their task. Simulation of a realistic traffic application over an area of 1 sq. km with a task map of size 1.5 KB shows that more than 90 % of nodes are tasked correctly. Zoom also outperforms Logical Neighborhoods, the state-of-the-art tasking protocol in task information size for similar tasks. Its encoded map size is always less than 50% of Logical Neighborhood's predicate size.

Wireless sensor networks are revolutionizing the instrumentation of the physical world, across sc... more Wireless sensor networks are revolutionizing the instrumentation of the physical world, across scientific, industrial and military applications. In this paper, we describe our efforts developing and classroom-testing hands-on materials for use in undergraduateaccessible courses on sensor networks. In Winter 2008 at Portland State University, we introduced an in-class laboratory component to a sensor networks course that had previously been entirely lecture-based. For the laboratory exercises, we utilized Sun's Java-programmable Sun SPOT [7] sensor network technology. We found the Sun SPOT based laboratory activities to be quite powerful as a teaching and excitement-fostering tool.

Computer Communications, Nov 1, 2006

In this paper, we describe SpeedNet, a GSM network variant which resembles an ad hoc wireless mob... more In this paper, we describe SpeedNet, a GSM network variant which resembles an ad hoc wireless mobile network where base stations keep track of the velocities of mobile users (cars). SpeedNet is intended to track mobile users and their speed passively for both speed policing and control of traffic. The speed of the vehicle is controlled in a speed critical zone by means of an electro-mechanical control system, suitably referred to as VVLS (Vehicular Velocity Limiting System). VVLS is mounted on the vehicle and responds to the command signals generated by the base station. It also determines the next base station to handoff, in order to improve the connection reliability and bandwidth efficiency of the underlying network. Robust Extended Kalman Filter (REKF) is used as a passive velocity estimator of the mobile user with the widely used proportional and integral controller speed control. We demonstrate through simulation and analysis that our prediction algorithm can successfully estimate the mobile user's velocity with low system complexity as it requires two closest mobile base station measurements and also it is robust against system uncertainties due to the inherent deterministic nature in the mobility model.

This paper investigates an anycast communication paradigm for a hybrid sensor/actuator network, c... more This paper investigates an anycast communication paradigm for a hybrid sensor/actuator network, consisting of both resource-rich and resource-impoverished devices. The key idea is to exploit the capabilities of resource-rich devices (called microservers) to reduce the communication burden on smaller, energy, bandwidth and memory constrained sensor nodes. The goal is to deliver sensor data to the nearest micro-server, which can (i) store it (ii) forward it to other micro-servers using out-of-band communication or (iii) perform the desired actuation. Our approach is to construct an anycast tree rooted at each potential event source, which micro-servers can dynamically join and leave. Our anycast mechanism is self-organizing, distributed, robust, scalable, and incurs very little overhead. ns-2 simulations show that our anycast mechanism can reduce network energy consumption by more than 50%, both the mean end-to-end latency of the transmission and the mean number of transmissions by more than 50%, and achieves 99% data delivery rate for low and moderate micro-server mobility rate.

In recent years a variety of new data dissemination protocols have been developed specifically fo... more In recent years a variety of new data dissemination protocols have been developed specifically for wireless sensor networks (WSN), but no realistic performance comparison between them has been attempted. This paper reports on the results of a simulation comparison made by an independent researcher using the ns-2.26[1] simulator for the WSN protocols: Directed Diffusion (DD)[2], Two-Tier Data Dissemination (TTDD) [3] and Gradient Broadcast (GRAB)[4]. Our performance study provides useful insights for the network designer-such as which protocols (and design choices) scale control traffic well, improve data delivery or reduce overall energy consumption. We observe that despite the designers intentions to make these protocols self-configuring, they in fact rely on a number of statically configured parameters which are the cause of the reduction in peformance. For example, the static preconfiguration of the cell size in TTDD. is one of the reasons why TTDD exhibits larger routing overhead than DD by 67.6% on average. Although GRAB produces approximately 93.6% smaller overhead than TTDD and 89.27% smaller than DD, because of statically configured amount credit GRAB delivers on average 6 times more of the redundant data packets than TTDD and DD. We suggest that making these protocols truly self-learning can significantly improve their performance, and comment on how some of these parameters can be dynamically derived through measurements of network and event dynamics.

Proceedings of the 11th International Conference on Smart Cities and Green ICT Systems

Proceedings of the 20th Annual International Conference on Mobile Systems, Applications and Services

The violation of information privacy in Smart Grids can be a significant barrier to customers' pa... more The violation of information privacy in Smart Grids can be a significant barrier to customers' participation. Employing privacy protection models such as K-anonymity in a Smart Grid implementation adds desirable privacy guarantees. This work provides an approach to applying the Mondrian algorithm to ensure data within the system excludes Personally Identifiable Information. Results suggest that a dynamically generated generalization hierarchy minimizes information loss incurred by the anonymization process. CCS CONCEPTS • Security and privacy → Privacy protections.

A noise map facilitates the monitoring of environmental noise pollution in urban areas. It can ra... more A noise map facilitates the monitoring of environmental noise pollution in urban areas. It can raise citizen awareness of noise pollution levels, and aid in the development of mitigation strategies to cope with the adverse effects. However, state-of-the-art techniques for rendering noise maps in urban areas are expensive and rarely updated (for months or even years), as they rely on population and traffic models rather than on real data. Smart phone based urban sensing can be leveraged to create an open and inexpensive platform for rendering up-to-date noise maps. In this paper, we present the design, implementation and performance evaluation of an end-to-end, context-aware, noise mapping system called Ear-Phone. Ear-Phone investigates the use of different interpolation and regularization methods to address the fundamental problem of recovering the noise map from incomplete and random samples obtained by crowdsourcing data collection. Ear-Phone, implemented on Nokia N95, N97 and HP ...

Ad hoc networks, Nov 1, 2006

In this paper, we consider the problem of network deployment in hybrid sensor networks, consistin... more In this paper, we consider the problem of network deployment in hybrid sensor networks, consisting of both resource-rich and resource-impoverished sensor devices. The resource-rich devices, called micro-servers, are more expensive but have significantly greater bandwidth and energy capabilities compared to the low-cost, lowpowered sensors. Such hybrid sensor networks have the potential to support the higher bandwidth communications of broadband sensor networking applications, as

ACM Transactions in Embedded Computing Systems, Oct 6, 2014

Crowd-sourced mobile embedded systems allow people to contribute sensor data, for critical applic... more Crowd-sourced mobile embedded systems allow people to contribute sensor data, for critical applications, including transportation, emergency response and eHealth. Data integrity becomes imperative as malicious participants can launch software and Sybil attacks modifying the sensing platform and data. To address these attacks, we develop (i) a Trusted Sensing Peripheral (TSP) enabling collection of high-integrity raw or aggregated data, and participation in applications requiring additional modalities; and (ii) a Secure Tasking and Aggregation Protocol (STAP) enabling aggregation of TSPs trusted readings by untrusted intermediaries, while efficiently detecting fabricators. Evaluations demonstrate that TSP and STAP are practical and energy-efficient.

Center for Embedded Network Sensing, 2000

Instrumenting the physical world through large networks of wireless sensor nodes, particularly fo... more Instrumenting the physical world through large networks of wireless sensor nodes, particularly for applications like environmental monitoring of water and soil, requires that these nodes be very small, light, untethered and unobtrusive. The problem of localization, i.e., determining where a given node is physically located in a network is a challenging one, and yet extremely crucial for many of these applications. Practical considerations such as the small size, form factor, cost and power constraints of nodes preclude the reliance on GPS (Global Positioning System) on all nodes in these networks. In this paper, we review localization techniques and evaluate the effectiveness of a very simple connectivity-metric method for localization in outdoor environments that makes use of the inherent radio-frequency (RF) communications capabilities of these devices. A fixed number of reference points in the network with overlapping regions of coverage transmit periodic beacon signals. Nodes use a simple connectivity metric, that is more robust to environmental vagaries, to infer proximity to a given subset of these reference points. Nodes localize themselves to the centroid of their proximate reference points. The accuracy of localization is then dependent on the separation distance between two adjacent reference points and the transmission range of these reference points. Initial experimental results show that the accuracy for 90% of our data points is within one-third of the separation distance. However future work is needed to extend the technique to more cluttered environments. Keywords-localization, location, radio-frequency wireless network. 1 We borrow the term localization from robotics, where it refers to the problem of determining the position of a mobile robot in some coordinate system.

Wireless sensor networks are poised to become an ubiquitous part of the computing landscape. We a... more Wireless sensor networks are poised to become an ubiquitous part of the computing landscape. We are developing and class-testing sensor network lab exercises. The goal is to enable undergraduate students to learn sensor network concepts in a hands-on manner, and build sensor networking applications. This demonstration of tracking a light contour using a network of SunSPOT devices showcases a project completed by students in less than two weeks at the end of our sensor network course.

Spatial localization or the ability to locate nodes is an important building block for next gener... more Spatial localization or the ability to locate nodes is an important building block for next generation pervasive computing systems, but a formidable challenge, particularly, for very small hardware and energy constrained devices, for noisy, unpredictable environments and for very large ad hoc deployed and networked systems. In this paper, we describe, validate and evaluate in real environments a very simple self localization methodology for RF-based devices based only on RF-connectivity constraints to a set of beacons (known nodes), applicable outdoors. Beacon placement has a significant impact on the localization quality in these systems. To self-configure and adapt the localization in noisy environments with unpredictable radio propagation vagaries, we introduce the novel concept of adaptive beacon placement. We propose several novel and density adaptive algorithms for beacon placement and demonstrate their effectiveness through evaluations. We also outline an approach in which beacons leverage a software controllable variable transmit power capability to further improve localization granularity. These combined features allow a localization system that is scalable and ad hoc deployable, long-lived and robust to noisy environments. The unique aspect of our localization approach is our emphasis on adaptive selfconfiguration.

USENIX conference on Hot topics in security, Aug 11, 2009

Grassroots Participatory Sensing empowers people to collect and share sensor data using mobile de... more Grassroots Participatory Sensing empowers people to collect and share sensor data using mobile devices across many applications, spanning intelligent transportation, air quality monitoring and social networking. In this paper, we argue that the very openness of such a system makes it vulnerable to abuse by malicious users who may poison the information, collude to fabricate information, or launch Sybils to distort that information. We propose and implement a novel trusted platform module (TPM), or angel based system that addresses the problem of providing sensor data integrity. The key idea is to provide a trusted platform within each sensor device to attest the integrity of sensor readings. We argue that this localizes integrity checking to the device, rather than relying on corroboration, making the system not only simpler, but also resistant to collusion and data poisoning. A "burnedin" private key in the TPM prevents users from launching Sybils. We also make the case for content protection and access control mechanisms that enable users to publish sensor data streams to selected groups of people and address it using broadcast encryption techniques.

Localization of small wireless sensor devices, with the deployment of the minimal infrastructure ... more Localization of small wireless sensor devices, with the deployment of the minimal infrastructure or hardware, has been the topic of significant research over the past few years. We have developed the Robust Extended Kalman Filter (REKF) localization system[1], which enables a mobile, data gathering robot to localize static sensor devices, by combining the RSSI data received from the motes, with estimates of its trajectory. The REKF localization system is particularly well suited to delay-tolerant sensor networks, where node positions need not be known in real time. We have observed accuracies ranging from approximately 30cm to 1m in practice.

In this paper, we provide a basic solution for online compression of data streams using error-bou... more In this paper, we provide a basic solution for online compression of data streams using error-bounded piecewiselinear approximation (PLA). We compare this method to the optimal (but offline) solution. Our current work in progress is developing an online PLA method that meets the same optimality constraints as the offline method. Also, the vertices of the constructed approximations are subsets of the sampled data points, which we believe to be a benefit in many scenarios.

Networked drones have the potential to transform various applications domains; yet their adoption... more Networked drones have the potential to transform various applications domains; yet their adoption particularly in indoor and forest environments has been stymied by the lack of accurate maps and autonomous navigation abilities in the absence of GPS, the lack of highly reliable, energy-efficient wireless communications, and the challenges of visually inferring and understanding an environment with resource-limited individual drones. We advocate a novel vision for the research community in the development of distributed, localized algorithms that enable the networked drones to dynamically coordinate to perform adaptive beam forming to achieve high capacity directional aerial communications, and collaborative machine learning to simultaneously localize, map and visually infer the challenging environment, even when individual drones are resource-limited in terms of computation and communication due to payload restrictions. CCS CONCEPTS • Networks → Location based services; Cross-layer protocols; • Computing methodologies → Ensemble methods.

As sensor networking technologies continue to develop, the notion of adding large-scale mobility ... more As sensor networking technologies continue to develop, the notion of adding large-scale mobility into sensor networks is becoming feasible by crowd-sourcing data collection to personal mobile devices. However, tasking such networks at fine granularity becomes problematic because the sensors are heterogeneous, owned by the crowd and not the network operators. In this paper, we present Zoom, a multi-resolution tasking framework for crowdsourced geo-spatial sensor networks. Zoom allows users to define arbitrary sensor groupings over heterogeneous, unstructured and mobile networks and assign different sensing tasks to each group. The key idea is the separation of the task information (what task a particular sensor should perform) from the task implementation (code). Zoom consists of (i) a map, an overlay on top of a geographic region, to represent both the sensor groups and the task information, and (ii) adaptive encoding of the map at multiple resolutions and region-of-interest cropping for resource-constrained devices, allowing sensors to zoom in quickly to a specific region to determine their task. Simulation of a realistic traffic application over an area of 1 sq. km with a task map of size 1.5 KB shows that more than 90 % of nodes are tasked correctly. Zoom also outperforms Logical Neighborhoods, the state-of-the-art tasking protocol in task information size for similar tasks. Its encoded map size is always less than 50% of Logical Neighborhood's predicate size.

Wireless sensor networks are revolutionizing the instrumentation of the physical world, across sc... more Wireless sensor networks are revolutionizing the instrumentation of the physical world, across scientific, industrial and military applications. In this paper, we describe our efforts developing and classroom-testing hands-on materials for use in undergraduateaccessible courses on sensor networks. In Winter 2008 at Portland State University, we introduced an in-class laboratory component to a sensor networks course that had previously been entirely lecture-based. For the laboratory exercises, we utilized Sun's Java-programmable Sun SPOT [7] sensor network technology. We found the Sun SPOT based laboratory activities to be quite powerful as a teaching and excitement-fostering tool.

Computer Communications, Nov 1, 2006

In this paper, we describe SpeedNet, a GSM network variant which resembles an ad hoc wireless mob... more In this paper, we describe SpeedNet, a GSM network variant which resembles an ad hoc wireless mobile network where base stations keep track of the velocities of mobile users (cars). SpeedNet is intended to track mobile users and their speed passively for both speed policing and control of traffic. The speed of the vehicle is controlled in a speed critical zone by means of an electro-mechanical control system, suitably referred to as VVLS (Vehicular Velocity Limiting System). VVLS is mounted on the vehicle and responds to the command signals generated by the base station. It also determines the next base station to handoff, in order to improve the connection reliability and bandwidth efficiency of the underlying network. Robust Extended Kalman Filter (REKF) is used as a passive velocity estimator of the mobile user with the widely used proportional and integral controller speed control. We demonstrate through simulation and analysis that our prediction algorithm can successfully estimate the mobile user's velocity with low system complexity as it requires two closest mobile base station measurements and also it is robust against system uncertainties due to the inherent deterministic nature in the mobility model.

This paper investigates an anycast communication paradigm for a hybrid sensor/actuator network, c... more This paper investigates an anycast communication paradigm for a hybrid sensor/actuator network, consisting of both resource-rich and resource-impoverished devices. The key idea is to exploit the capabilities of resource-rich devices (called microservers) to reduce the communication burden on smaller, energy, bandwidth and memory constrained sensor nodes. The goal is to deliver sensor data to the nearest micro-server, which can (i) store it (ii) forward it to other micro-servers using out-of-band communication or (iii) perform the desired actuation. Our approach is to construct an anycast tree rooted at each potential event source, which micro-servers can dynamically join and leave. Our anycast mechanism is self-organizing, distributed, robust, scalable, and incurs very little overhead. ns-2 simulations show that our anycast mechanism can reduce network energy consumption by more than 50%, both the mean end-to-end latency of the transmission and the mean number of transmissions by more than 50%, and achieves 99% data delivery rate for low and moderate micro-server mobility rate.

In recent years a variety of new data dissemination protocols have been developed specifically fo... more In recent years a variety of new data dissemination protocols have been developed specifically for wireless sensor networks (WSN), but no realistic performance comparison between them has been attempted. This paper reports on the results of a simulation comparison made by an independent researcher using the ns-2.26[1] simulator for the WSN protocols: Directed Diffusion (DD)[2], Two-Tier Data Dissemination (TTDD) [3] and Gradient Broadcast (GRAB)[4]. Our performance study provides useful insights for the network designer-such as which protocols (and design choices) scale control traffic well, improve data delivery or reduce overall energy consumption. We observe that despite the designers intentions to make these protocols self-configuring, they in fact rely on a number of statically configured parameters which are the cause of the reduction in peformance. For example, the static preconfiguration of the cell size in TTDD. is one of the reasons why TTDD exhibits larger routing overhead than DD by 67.6% on average. Although GRAB produces approximately 93.6% smaller overhead than TTDD and 89.27% smaller than DD, because of statically configured amount credit GRAB delivers on average 6 times more of the redundant data packets than TTDD and DD. We suggest that making these protocols truly self-learning can significantly improve their performance, and comment on how some of these parameters can be dynamically derived through measurements of network and event dynamics.

Proceedings of the 11th International Conference on Smart Cities and Green ICT Systems

Proceedings of the 20th Annual International Conference on Mobile Systems, Applications and Services

The violation of information privacy in Smart Grids can be a significant barrier to customers' pa... more The violation of information privacy in Smart Grids can be a significant barrier to customers' participation. Employing privacy protection models such as K-anonymity in a Smart Grid implementation adds desirable privacy guarantees. This work provides an approach to applying the Mondrian algorithm to ensure data within the system excludes Personally Identifiable Information. Results suggest that a dynamically generated generalization hierarchy minimizes information loss incurred by the anonymization process. CCS CONCEPTS • Security and privacy → Privacy protections.

A noise map facilitates the monitoring of environmental noise pollution in urban areas. It can ra... more A noise map facilitates the monitoring of environmental noise pollution in urban areas. It can raise citizen awareness of noise pollution levels, and aid in the development of mitigation strategies to cope with the adverse effects. However, state-of-the-art techniques for rendering noise maps in urban areas are expensive and rarely updated (for months or even years), as they rely on population and traffic models rather than on real data. Smart phone based urban sensing can be leveraged to create an open and inexpensive platform for rendering up-to-date noise maps. In this paper, we present the design, implementation and performance evaluation of an end-to-end, context-aware, noise mapping system called Ear-Phone. Ear-Phone investigates the use of different interpolation and regularization methods to address the fundamental problem of recovering the noise map from incomplete and random samples obtained by crowdsourcing data collection. Ear-Phone, implemented on Nokia N95, N97 and HP ...