Mobile Systems Research with Drones

Robot vehicle platforms, often called “drones”, offer exciting new opportuni- ties for mobile computing. While many systems respond to device mobility (such as smartphones), drones allow computer systems to actively control device location, allowing them to interact with the physical world in new ways and with new-found scale, efficiency, or precision

Poster Abstract: Bits and Watts: Improving energy disaggregation performance using power line communication modems

Non-intrusive load monitoring (NILM) or energy disaggregation, aims to disaggregate a household's electricity consumption into constituent appliances. More than three decades of work in NILM has resulted in the development of several novel algorithmic approaches. However, despite these advancements, two core challenges still exist: i) disaggregating low power consumption appliances and ii) distinguishing between multiple instances of similar appliances. These challenges are becoming increasingly important due to an increasing number of appliances and increased usage of electronics in homes. Previous approaches have attempted to solve these problems using expensive hardware involving high sampling rates better suited to laboratory settings, or using additional number of sensors, limiting the ease of deployment. In this work, we explore using commercial-off-the-shelf (COTS) power line communication (PLC) modems as an inexpensive and easy to deploy alternative solution to these problems. We use the reduction in bandwidth between two PLC modems, caused due to the change in PLC modulation scheme when different appliances are operated as a signature for an appliance. Since the noise generated in the powerline is dependent both on type and location of an appliance, we believe that our technique based on PLC modems can be a promising addition for solving NILM

Lazy Preemption to Enable Path-Based Analysis of Interrupt-Driven Code

ABSTRACT One of the important factors in ensuring the correct functionality of wireless sensor networks (WSNs) is the reliability of the software running on individual sensor nodes. Research has shown that path-sensitive static analysis is effective for bug detection and fault diagnosis; however, path-sensitive analysis is prohibitively expensive when applied to a WSN application due to the large state space caused by arbitrary interrupt preemptions. In this paper, we propose a new execution model called lazy preemption that reduces this state space by restricting interrupt handlers to a set of predetermined preemption points, if possible. This execution model allows us to represent the program with an inter-interrupt control flow graph (IICFG), which is easier to analyze than the original CFGs with arbitrary interrupt preemptions

CAMA: Efficient Modeling of the Capture Effect for Low Power Wireless Networks

Network simulation is an essential tool for the design and evaluation of wireless network protocols, and realistic channel modeling is essential for meaningful analysis. Recently, several network protocols have demonstrated substantial network performance improvements by exploiting the capture effect, but existing models of the capture effect are still not adequate for protocol simulation and analysis. Physical-level models that calculate the signal-to-interference-plus-noise ratio (SINR) for every incoming bit are too slow to be used for large-scale or long-term networking experiments, and link-level models such as those currently used by the NS2 simulator do not accurately predict protocol performance. In this article, we propose a new technique called the capture modeling algorithm (CAMA) that provides the simulation fidelity of physical-level models while achieving the simulation time of link-level models. We confirm the validity of CAMA through comparison with the empirical traces of the experiments conducted by various numbers of CC1000 and CC2420-based nodes in different scenarios. Our results indicate that CAMA can accurately predict the packet reception, corruption, and collision detection rates of real radios, while existing models currently used by the NS2 simulator produce substantial prediction error

Categories and Subject Descriptors D.1.2 [PROGRAMMING TECHNIQUES]: Automatic Programming General Terms Language, Design

One of the primary barriers to the widespread use of sensor networks by non-technical users today is the inability to automatically synthesize semantic values such as building activity from raw sensor data from for example intrared breakbeams or motion detectors