Brian Shucker

MANTIS OS: an embedded multithreaded operating system for wireless micro sensor platforms

The MANTIS MultimodAl system for NeTworks of In-situ wireless Sensors provides a new multithreaded cross-platform embedded operating system for wireless sensor networks. As sensor networks accommodate increasingly complex tasks such as compression/aggregation and signal processing, preemptive multithreading in the MANTIS sensor OS (MOS) enables micro sensor nodes to natively interleave complex tasks with time-sensitive tasks, thereby mitigating the bounded buffer producer-consumer problem. To achieve memory efficiency, MOS is implemented in a lightweight RAM footprint that fits in less than 500 bytes of memory, including kernel, scheduler, and network stack. To achieve energy efficiency, the MOS power-efficient scheduler sleeps the microcontroller after all active threads have called the MOS sleep() function, reducing current consumption to the μA range. A key MOS design feature is flexibility in the form of cross-platform support and testing across PCs, PDAs, and different micro sensor platforms. Another key MOS design feature is support for remote management of in-situ sensors via dynamic reprogramming and remote login.

MANTIS: system support for multimodAl NeTworks of in-situ sensors

The MANTIS MultimodAl system for NeTworks of In-situ wireless Sensors provides a new multithreaded embedded operating system integrated with a general-purpose single-board hardware platform to enable flexible and rapid prototyping of wireless sensor networks. The key design goals of MANTIS are ease of use, i.e. a small learning curve that encourages novice programmers to rapidly prototype novel sensor networking applications in software and hardware, as well as flexibility, so that expert researchers can leverage or develop advanced software features and hardware extensions to suit the needs of advanced research in wireless sensor networks.

Convergence-Preserving Switching for Topology-Dependent Decentralized Systems

Stability analysis of decentralized control mechanisms for networked coordinating systems has generally focused on specific controller implementations, such as nearest-neighbor and other types of proximity graph control laws. This approach often misses the need for the addition of other control structures to improve global characteristics of the network. An example of such a situation is the use of a Gabriel graph, which is essentially a nearest-neighbor rule modified to ensure global connectivity of the network if the agents are pairwise connected through their sensor inputs. We present a method of ensuring provable stability of decentralized switching systems by employing a hysteresis rule that uses a zero-sum consensus algorithm. We demonstrate the application of this result to several special cases, including nearest-neighbor control laws, Gabriel graph rules, diffuse target tracking, and hierarchical heterogeneous systems.

VLM/sup 2/: a very lightweight mobile multicast system for wireless sensor networks

Wireless sensor networks require lightweight routing tailored for sensor devices with severe memory, power, and cost constraints. Such lightweight protocols must also support mobility and fault tolerance. The very Lightweight Mobile Multicast (VLM/sup 2/) system addresses these concerns, introducing multicast support into wireless sensor networks. In simulation and in a true implementation on hardware Motes, VLM/sup 2/ achieves multicast with a lightweight footprint of no more than 17 kb per node and also responds with agility to a wide range of mobility.

Scalable Control of Distributed Robotic Macrosensors

This paper describes a control mechanism by which large numbers of inexpensive robots can be deployed as a distributed remote sensing instrument, and in which the desired large-scale properties of the sensing instrument emerge from the simple pair-wise interactions of its component robots. Such sensing instruments are called distributed robotic macrosensors. Robots in the macrosensor interact with their immediate neighbors using a virtual spring mesh abstraction, which is governed by a simple physics model. By carefully defining the nature of the spring mesh and the associated physics model, it is possible to create a number of desirable global behaviors without any global control or configuration. Properties of the resulting macrosensor include arbitrary scalability, the ability to function in complex environments, sophisticated target tracking ability, and natural fault tolerance. We describe the control mechanisms that yield these results, and the simulation results that demonstrate their efficacy.

Target tracking with distributed robotic macrosensors

We have developed a novel control mechanism that deploys a large number of inexpensive robots as a distributed remote sensing array, called a distributed robotic macrosensor (DRM). This DRM has the capability to track targets of both a discrete (e.g., a vehicle) and diffuse (e.g., a chemical plume) nature. Attack resistance is an inherent property of the DRM as well. A relatively simple virtual spring mesh abstraction is used to provide fully distributed control that is both flexible and fault-tolerant. We describe the algorithms for spring mesh formation and control, discrete target tracking, and diffuse target tracking. We also present simulation results demonstrating the efficacy and robustness of DRMs

A method of cooperative control using occasional non-local interactions

Current approaches to distributed control involving many robots generally restrict interactions to pairs of robots within a threshold distance. While this allows for provable stability, there are performance costs associated with the lack of long-distance information. We introduce the acute angle switching algorithm, which allows a small number of long-range interactions in addition to interactions with nearby neighbors, without sacrificing provable stability. We prove several formal properties of the acute angle switching algorithm, including system-wide connectivity. Further, we show simulation results demonstrating the efficacy and robustness of multi-robot systems based on the acute angle switching algorithm

Switching Rules for Decentralized Control with Simple Control Laws

We introduce a novel method for enforcing stability on a decentralized control system. In contrast to previous work, our approach allows for the use of a wide variety of simple control laws, while still providing for a formal proof of stability. Our motivating example uses a simple geometric switching function coupled with PD control that has an intuitive interpretation as a virtual spring mesh. Building on this example, we show a general proof technique that applies to a large class of decentralized control systems. Furthermore, we describe additional cases that illustrate how our technique can be applied to useful systems that are straightforward to implement.

An approach to switching control beyond nearest neighbor rules

Current approaches to distributed control involving many robots generally restrict interactions to pairs of robots within a threshold distance. While this allows for provable stability, there are performance costs associated with the lack of long-distance information. We introduce the acute angle switching algorithm, which allows a small number of long-range interactions in addition to interactions with nearby neighbors. We show that the acute angle switching algorithm provides an improvement in performance while retaining the quality of provable stability

Poster abstract: mantis - system supports for m ultimod A l N e T works on In-Situ sensors

The <i>MANTIS</i> <i>M</i>ultimod<i>A</i>l system for <i>N</i>e<i>T</i>works of In-situ wireless Sensors provides a new multithreaded embedded operating system integrated with a general-purpose single-board hardware platform to enable flexible and rapid prototyping of wireless sensor networks.