Distributed Communication in Swarms of Autonomous Underwater Vehicles

Effective communication mechanisms are a key requirement for schools of submersible robots and their meaningful deployment. Large schools of identical submersibles require a fully distributed communication system which scales well and optimises for ”many-to-many” communication (omnicast, also known as gossiping). As an additional constraint, communication channels under water are typically very low bandwidth and short range. This thesis discusses possible electric and electro-magnetic wireless communication channels suitable for underwater environments. Theoretical findings on the omnicast communication problem are presented, as well as the implementation of a distributed time division multiple access (TDMA) scheduling algorithm in simulation and in hardware. It is shown theoretically and in simulation that short range links in a robotic swarm are actually an advantage, compared to links that cover large parts of the network. Experiments were carried out on custom-developed digital long-wave radio and optical link modules. The results of the experiments are used to revisit the initial assumptions on communication in multi-hop wireless networks

Passive mobile robot localization within a fixed beacon field

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.Includes bibliographical references (p. 67-70).This thesis describes a geometric algorithm for the localization of mobile nodes in networks of sensors and robots using bounded regions, in particular we explore the range-only and angle-only measurement cases. The algorithm is a minimalistic approach to localization and tracking when dead reckoning is too inaccurate to be useful. The only knowledge required about the mobile node is its maximum speed. Geometric regions are formed and grown to account for the motion of the mobile node. New measurements introduce new constraints which are propagated back in time to refine previous localization regions. The mobile robots are passive listeners while the sensor nodes actively broadcast making the algorithm scalable to many mobile nodes while maintaining the privacy of individual nodes. We prove that the localization regions found are optimal -- that is, they are the smallest regions which must contain the mobile node at that time. We prove that each new measurement requires quadratic time in the number of measurements to update the system, however, we demonstrate experimentally that this can be reduced to constant time. Numerous simulations are presented, as well as results from an underwater experiment conducted at the U.C. Berkeley R.B. Gump Biological Research Station on the island of Moorea, French Polynesia.by Carrick Detweiler.S.M

Elasmobranchs as living resources: Advances in the biology, ecology, systematics, and the status of the fisheries

This report owes its genesis to the foresight and enthusiam of Dr. Kazuhiro Mizue. By happy circumstance, Professor Mizue contacted me in 1983 with his visionary ideas on cooperative programs. He noted that the time was right because the Japan Society for the Promotion of Science and the National Science Foundation had mutually given priority to cooperative programs in marine biology. I therefore agreed to act as the U.S. coordinator and proposed to NSF, a short trip to Japan to negotiate site visits and timing with ten previously appointed Japanese scientists and, if that trip were successful, to negotiate a joint research project, possibly followed by a joint seminar. (PDF file contains 528 pages.

Bulletin of The University of New Hampshire. Undergraduate Catalog 1991-1992

The Bulletin of the University of New Hampshire Undergraduate Catalog contains general information about the university. It is published twice in December, January, and February, and once each in March, April, July, and August

Using MapReduce Streaming for Distributed Life Simulation on the Cloud

Distributed software simulations are indispensable in the study of large-scale life models but often require the use of technically complex lower-level distributed computing frameworks, such as MPI. We propose to overcome the complexity challenge by applying the emerging MapReduce (MR) model to distributed life simulations and by running such simulations on the cloud. Technically, we design optimized MR streaming algorithms for discrete and continuous versions of Conway’s life according to a general MR streaming pattern. We chose life because it is simple enough as a testbed for MR’s applicability to a-life simulations and general enough to make our results applicable to various lattice-based a-life models. We implement and empirically evaluate our algorithms’ performance on Amazon’s Elastic MR cloud. Our experiments demonstrate that a single MR optimization technique called strip partitioning can reduce the execution time of continuous life simulations by 64%. To the best of our knowledge, we are the first to propose and evaluate MR streaming algorithms for lattice-based simulations. Our algorithms can serve as prototypes in the development of novel MR simulation algorithms for large-scale lattice-based a-life models.https://digitalcommons.chapman.edu/scs_books/1014/thumbnail.jp