Autonomous Construction with Compliant Building Material

In this paper, we develop an autonomous construction system in which a self-contained ground robot builds a protective barrier by means of compliant pockets (i.e., filled bags). We present a stochastic control algorithm based on two biological mechanisms (stigmergy and templates) that takes advantage of compliant pockets for autonomous construction. The control algorithm guides the robot to build the structure without relying on any external motion capture system or external computer. We propose a statistical model to represent the structures built with the compliant pockets, and we provide a set of criteria for assessing the performance of the proposed system. To demonstrate the feasibility of the proposed system, real-robot experiments were carried out. In each experiment, the robot successfully built the structure. The results show the viability of the proposed autonomous construction system

Cooperation through self-assembly in multi-robot

This article illustrates the methods and results of two sets of experiments in which a group of mobile robots, called s-bots, are required to physically connect to each other, that is, to self-assemble, to cope with environmental conditions that prevent them from carrying out their task individually. The first set of experiments is a pioneering study on the utility of self-assembling robots to address relatively complex scenarios, such as cooperative object transport. The results of our work suggest that the s-bots possess hardware characteristics which facilitate the design of control mechanisms for autonomous self-assembly. The control architecture we developed proved particularly successful in guiding the robots engaged in the cooperative transport task. However, the results also showed that some features of the robots’ controllers had a disruptive effect on their performances. The second set of experiments is an attempt to enhance the adaptiveness of our multi-robot system. In particular, we aim to synthesise an integrated (i.e., not-modular) decisionmaking mechanism which allows the s-bot to autonomously decide whether or not environmental contingencies require self-assembly. The results show that it is possible to synthesize, by using evolutionary computation techniques, artificial neural networks that integrate both the mechanisms for sensory-motor coordination and for decision making required by the robots in the context of self-assembly

System for deployment of groups of unmanned micro aerial vehicles in GPS-denied environments using onboard visual relative localization

A complex system for control of swarms of micro aerial vehicles (MAV), in literature also called as unmanned aerial vehicles (UAV) or unmanned aerial systems (UAS), stabilized via an onboard visual relative localization is described in this paper. The main purpose of this work is to verify the possibility of self-stabilization of multi-MAV groups without an external global positioning system. This approach enables the deployment of MAV swarms outside laboratory conditions, and it may be considered an enabling technique for utilizing fleets of MAVs in real-world scenarios. The proposed visual-based stabilization approach has been designed for numerous different multi-UAV robotic applications (leader-follower UAV formation stabilization, UAV swarm stabilization and deployment in surveillance scenarios, cooperative UAV sensory measurement) in this paper. Deployment of the system in real-world scenarios truthfully verifies its operational constraints, given by limited onboard sensing suites and processing capabilities. The performance of the presented approach (MAV control, motion planning, MAV stabilization, and trajectory planning) in multi-MAV applications has been validated by experimental results in indoor as well as in challenging outdoor environments (e.g., in windy conditions and in a former pit mine)

The State of Coral Reef Ecosystems of the United States and Pacific Freely Associated States: 2002

Called for by the U.S. Coral Reef Task Force’s (USCRTF) National Action Plan to Conserve Coral Reefs, this is the first biennial report on the condition of coral reefs. It is the scientific baseline for subsequent reports on the health of U.S. coral reef ecosystems that are to be used by NOAA and others to evaluate the efficacy of coral reef conservation and management practices. The National Oceanic and Atmospheric Administration’s National Ocean Service led the development of this report. It was authored by 38 experts and supported by 79 contributors from government agencies and non-governmental organizations across the nation and internationally. Over 100 Task Force members and other notable scientists have reviewed this document

Survey and Estimates of Commercially Viable Populations of the Sea Cucumber Actinopyga mauritiana (Echinodermata: Holothuroidea), on Tinian Island, Commonwealth of the Northern Mariana Islands

A survey was conducted in 1997 to assess commercially viable populations of the surf redfish, Actinopyga mauritiana, and establish a harvest quota for those populations on the island of Tinian. A simple random sampling approach was employed using circular plots as samples. Outer reef flat and reef slope habitats were sampled, producing a total of 333 samples over a 2-month period, with a preharvest population estimate of 71,034. A harvest quota of 17,893 surf redfish was established due to stock depletions on both Rota and Saipan, uncertainty of the density required to ensure successful reproduction of the species, and high degree of uncertainty in the population estimates. It was determined that a stratified sampling approach utilizing either simple proportional or optimal allocation would have resulted in more precise estimates, and these approaches are favored for any future survey work. Population estimates should be revised when more accurate estimates of A. mauritiana habitats become available

Summary of recorded cetacean strandings in the Commonwealth of the Northern Mariana Islands

Abstract-Documented strandings in the Commonwealth of the Northern Mariana Islands over the past 17 years are reviewed with recorded autopsy information provided. Most of the strandings occurred on the island of Saipan, although two whales were noted to have stranded during this period on Tinian, one identified as Balaenoptera edeni, the Byrdes whale, while the other was not identified. The planned expansion of military activities in the Marianas Archipelago, particularly the use of sonar and the potential impact on cetaceans, is noted

Life history characteristics and status of the Pacific yellowtail emperor, Lethrinus atkinsoni (Seale 1910), in the Commonwealth of the Northern Mariana Islands

Abstract Life history characteristics of the Pacific yellowtail emperor, Lethrinus atkinsoni, were described from commercial samples in the Commonwealth of the Northern Mariana Islands spanning a 28‐month market sampling period. Derived statistics pertaining to growth, life span, mortality and reproductive features were obtained through analyses of sectioned sagittal otoliths and gonad tissues. Maximum age observed was 18 years, with females attaining 50% sexual maturity at 3.3 years at a fork length of 20.9 cm; too few male specimens precluded male maturation estimates. We concluded that the species exhibited an undetermined sexual pattern as no evidence of prior female function was observed in mature males. No annual spawning periods were identifiable. Early growth rates estimated by settlement size‐constrained VBGF models using fish landed by the nighttime commercial spear fishery (NCSF) were rapid. Exploitation rates indicated very low‐to‐moderate levels of exploitation. Boat‐based fishing efforts from the NCSF captured the larger individuals of the species, whereas shore‐based efforts captured the vast majority of individuals representing sizes generally below that of the estimated 50% maturation level. Extensive fishery‐independent in situ diver observations indicated the species may have a restricted range. Expanded fishery‐dependent collection of L. atkinsoni specimens and studies of its movement ecology at Saipan would provide additional input for fishery management, as well as a formal stock assessment which juvenile‐biased catches indicate are necessary

Cooperation Through Self-Assembly in Multi-Robot Systems

This article illustrates the methods and results of two sets of experiments in which a group of mobile robots, called s-bots, are required to physically connect to each other, that is, to self-assemble, to cope with environmental conditions that prevent them from carrying out their task individually. The first set of experiments is a pioneering study on the utility of self-assembling robots to address relatively complex scenarios, such as cooperative object transport. The results of our work suggest that the s-bots possess hardware characteristics which facilitate the design of control mechanisms for autonomous self-assembly. The control architecture we developed proved particularly successful in guiding the robots engaged in the cooperative transport task. However, the results also showed that some features of the robots ’ controllers had a disruptive effect on their performances. The second set of experiments is an attempt to enhance the adaptiveness of our multi-robot system. In particular, we aim to synthesise an integrated (i.e., not-modular) decisionmaking mechanism which allows the s-bot to autonomously decide whether or not environmental contingencies require self-assembly. The results show that it is possible to synthesize, by using evolutionary computation techniques, artificial neural networks that integrate both the mechanisms for sensory-motor coordination and for decision making required by the robots in the context of self-assembly. This work was supported by the SWARM-BOTS project, funded by the Future and Emerging Technologie