Johnathan M. Reason

Energy-Efficient Routing in Linear Wireless Sensor Networks

Wireless sensor networks are used for structure monitoring and border surveillance. Typical applications, such as sensors embedded in the outer surface of a pipeline or mounted along the supporting structure of a bridge, feature a linear sensor arrangement. Economical power use of sensor nodes is essential for long-lasting operation. In this paper, we present MERR (minimum energy relay routing), a novel approach to energy-efficient data routing to a single control center in a linear sensor topology. Based on an optimal transmission distance, relay paths are established that aim for minimizing the total power consumption. We study MERR by both stochastic analysis and simulation, comparing it to other possible approaches and a theoretically optimal protocol. We find that MERR consumes 80% less power than conventional approaches and performs close to the theoretical optimum for practicable sensor networks.

The Design and Implementation of a Smart Building Control System

A significant proportion of total worldwide energy is consumed by buildings. For example, buildings in the US account for about 40 percent of total energy consumption and greenhouse gas emission. Making buildings more energy-efficient is an important step to reduce our energy consumption and carbon emission in the combat with global climate change. Broad participation by consumers, business owners, and governments is required to continuously improve on energy efficiency for new and existing buildings and to achieve the global greenhouse gas emission reduction objectives. This paper provides a software system perspective of improving energy efficiency for buildings. It proposes an architecture that allows for phased investments in technologies to capture the returns from energy savings in various use cases. In addition, it addresses the needs and objectives of different stakeholders, including owners, operators, users, and utility providers. A proof-of-concept implementation of the architecture is used to demonstrate the support for building-wide energy conservation policies using real-time energy pricing and individual occupants’ locations and preferences. It shows that the proposed architecture enables fine-grained building control and reduces energy consumption while maximizing its occupants’ comfort.

Localized power-aware routing in linear wireless sensor networks

Energy-efficency is a key concern when designing protocols for wireless sensor networks (WSN). This is of particular importance in commercial applications where demonstrable return on investment is a crucial factor. One such commercial application that motivated this work is telemetry and control for freight railroad trains. Since a railroad train has a global linear structure by nature, we consider in this paper linear WSNs as sensor networks having, roughly, a linear topology. Aiming at such networks, we introduce two routing schemes that efficiently utilize energy: Minimum Energy Relay Routing (MERR) and Adaptive MERR (AMERR). We derive a theoretical lower bound on the optimal power consumption of routing in a linear WSN, where we assume a Poisson model for the distribution of nodes along a linear path. We evaluate the efficiency of our protocols with respect to the theoretical optimal lower bound and with respect to other well-known protocols. AMERR achieves optimal performance for practical deployment settings, while MERR rapidly approaches optimal performance as sensors are more densely deployed. Compared to other protocols, we show that MERR and AMERR are less complex and have better scalability. We also postulate how both protocols might be generalized to a two-dimensional WSN.

Efficacy of techniques for responsiveness in a wide-area publish/subscribe system

As the multiplicity of organizational domains often span across nations, or even continents, the need for federated communications across domains becomes paramount. Consequently, messaging middleware has become critical towards enabling cross-domain, wide-area federations. Cross-domain federation has placed increased emphasis on the need for the messaging system to provide Quality of Service (QoS), particularly with respect to responsive delivery of messages. Responsiveness, or timely delivery of messages, is critical in real-world services, such as a smart utility grid system. This study explores the efficacy of providing responsiveness in wide-area publish/subscribe messaging by evaluating several key techniques for managing latency. Specifically, this paper evaluates the following techniques: proactive best-path routing, reactive QoS-aware routing, and multipath routing. We present Harmony, a QoS-aware publish/subscribe middleware system, that adapts these techniques in order to provide responsive and high availability messaging. This study seeks to provide an in-depth understanding of how different techniques to manage responsiveness affect the end-to-end performance under various network conditions.

A model-driven approach to RFID application programming and infrastructure management

This paper describes a model-driven methodology to provide a systematic means of programming RFID applications and managing a distributed RFID infrastructure. The centerpiece of the approach is a model that captures the device infrastructure, business operation structure, and their relationship. Building on the model, a management system can be designed to support various management tasks effectively, such as the enrollment, provisioning, and monitoring of devices. Similarly an application framework can be created for solution developers to create distributed RFID applications. Applications can be written against a business operation model and deployed on an evolving device infrastructure. A prototype shows that the approach facilitates the management and programming of an RFID infrastructure

Ambient intelligence for freight railroads

Within the freight railroad industry, there is currently an industrywide effort to enable intelligent telemetry for freight trains. The conventional wisdom is that greater visibility of the status and proper functioning of trains would enable business transformation in numerous areas, including predictive maintenance, schedule optimization, and asset utilization. However, this effort to derive business value through new technology may also have significant environmental benefits. For example, failure prediction can drastically reduce derailments, thereby protecting the environment from the harmful effects of hazardous material spills. Equally important, better visibility of trains can lead to more efficient scheduling of trains, allowing more trains to move freight. Studies show that trains are three times more fuel efficient than trucks, and transferring just 1% of truck freight to railroads can reduce greenhouse gas emissions by 1.2 million tons annually. In this paper, we describe the potential benefits of employing a new, intelligent telemetry infrastructure for freight railroads. One proposed approach called SEAIT, or Sensor Enabled Ambient Intelligent Telemetry, is a wireless sensor network approach to supporting sensing and communication for advanced freight transportation scenarios. As part of a proof-of-technology exploration, we describe some preliminary performance results of SEAIT.

Delay-Cognizant Reliable Delivery for Publish/Subscribe Overlay Networks

The number of real-world applications that require QoS guarantees is constantly increasing and they often follow the publish/subscribe (pub/sub)messaging paradigm, which provides loosely coupled many-to-many communication. Many QoS-aware systems use overlay networks as they allow flexible routing. To provide QoS-aware pub/sub messaging in overlay networks, the messaging system should be adaptive to the changes in network conditions (such as delay and failures). However, many pub/sub systems depend on a flexed routing topology and it is costly to rebuild this topology in case of failures. This study seeks to address this challenge with Delay-Cognizant Reliable Delivery (DCRD), a novel and delay-aware dynamic routing algorithm to provide reliable message delivery for pub/sub overlay networks. For reliable message delivery, DCRD no longer uses a flxed routing topology. Instead, it dynamically switches among different links to bypass link failures and increase the chance to meet QoS requirement. Each node tries different neighboring nodes in an order that is mathematically proven to minimize the expected delay of packet delivery. With all possible neighboring nodes sorted this way, DCRD guarantees that packets are delivered as long as there exists a path between the publisher and subscriber and that the expected delay is minimized. DCRD is extensively evaluated in simulation with comparison to existing tree-based routing approaches as well as a multi path approach using different network topologies, delay constraints, and loss probabilities. Simulation results show that DCRD performs better than all the baselines, providing reliable message delivery and satisfying the delay requirement for more than 98% of messages when the link failure probability is 4% or less.

A framework for managing the solution life cycle of event-driven pervasive applications

Event-driven, embedded applications that embody the composition of many disparate components are emerging as an important class of pervasive applications. For such applications, realizing solutions often requires a breadth of expertise. Consequently, managing the solution life cycle can be a very complex, time-intensive process. In this paper, we present a framework that eases the complexity of managing the life cycle of event-driven, pervasive solutions. We call this framework Rapid Integrated Solution Enablement or RISE. Component composition and software reuse are two central concepts of RISE, where solutions are graphically composed from reusable components using a visual editor. We describe the RISE architecture and discuss an initial prototype implementation that leverages open source technologies, such as Eclipse. Additionally, we illustrate the efficacy of RISE with an example solution for RFID supply chain logistics

Intelligent Telemetry for Freight Trains

Within the North American freight railroad industry, there is currently an effort to enable more intelligent telemetry for freight trains. By enabling greater visibility of their rolling stock, including locomotives and railroad cars, railroad companies hope to improve their asset utilization, operational safety, and business profitability. Different communication and sensing technologies are being explored and one candidate technology is wireless sensor networks (WSN). In this article, we present Sensor-Enabled Ambient-Intelligent Telemetry for Trains (SEAIT), which is a WSN-based approach to supporting sensing and communications for advanced freight transportation scenarios. As part of a proof-of-technology exploration, SEAIT was designed to address key requirements of industry proposed applications. We introduce several of these applications and highlight the challenges, which include high end-to-end reliability over many hops, low-latency delivery of emergency alerts, and accurate identification of train composition. We present the architecture of SEAIT and evaluate it against these requirements using an experimental deployment.

Logical RFID Reader Using Hybrid Active–Passive Solution

Radio-frequency identification (RFID) has been applied widely in applications such as supply chain visibility, pharmaceutical track and trace, etc. The standards body EPCglobal defines various interfaces in the electronic product code (EPC) network architecture to facilitate the interoperability of different applications. Logical reader is a concept defined in the application level events (ALE) specification to shield applications from knowing the physical device infrastructure. This paper proposes a new approach to the logical reader abstraction, which is defined using spatial zones and implemented by combining mobile, passive RFID with positioning technologies, such as active RFID. This hybrid approach exploits the best benefits of passive and active RFID, while maintaining compatibility with EPC standards for accessing logical readers via ALE. An evaluation of competing approaches is presented. The study shows that this spatial-zone-based design enables fine grain tracking of assets at lower infrastructure cost as compared to existing techniques (e.g., using active RFID only). The study also analyzes the accuracy of the proposed approach using numerical simulation. The results show that it outperforms a widely used chokepoint-based solution under realistic operating conditions.