An fMRI study of violations of social expectations: When people are not who we expect them to be

The current study examines the effect of violations of social expectancies on the neural substrates of person perception. In an event-related fMRI experiment, participants were presented with the photographs of either Republican or Democrat politicians paired with either typical Republican or Democrat political views (e.g., “wants a smaller government” or “wants liberal supreme court judges”). Subjects were asked to form an impression of the targets using information about both their political affiliation and their political views. Of interest was the contrast between stereotypically congruent trials and stereotypically incongruent trials. The results reveal that brain regions previously involved in mentalizing (i.e., temporoparietal junction and medial prefrontal cortex) are preferentially recruited when viewing incongruent social targets

Sensitivity of AUV added mass coefficients to variations in hull and control plane geometry

The sensitivity of the added mass coefficients of a typical autonomous underwater vehicle (AUV) to changes in geometric parameters was investigated. Qualitative deductions were made concerning the effect of geometric variations. Then the added mass coefficients for several configurations of body geometry were generated for the Canadian Self-Contained Off-the-shelf Underwater Testbed (C-SCOUT) vehicle using the computer program Estimate Submarine Added Mass (ESAM). The changes in the added mass coefficients have direct relationships to the varied parameter. The results presented here are specific to the C-SCOUT, but may be extended to similar axisymmetric bodies.Peer reviewed: YesNRC publication: Ye

Sensitivity of AUV response to variations in hydrodynamic parameters

The sensitivity of the response of a typical AUV to changes in hydrodynamic parameters is examined. The analysis is primarily performed using a computer model of an axi-symmetric vehicle typical of many AUVs in service today. The vehicle used is the Canadian Self-Contained Off-the-shelf Underwater Testbed (C-SCOUT), designed and built by graduate and work term students. The fully nonlinear computer model is based on Newton?Euler equations of motion, and uses the component build-up method to describe the excitation forces. The hydrodynamic parameters are varied in a series of simulations with the computer model; the response being analyzed for specific performance indicators.Peer reviewed: YesNRC publication: Ye

AUV control in the presence of fin actuator faults

Autonomous underwater vehicles (AUV) are rapidly becoming useful and versatile tools in the ocean environment. They have only recently matured to the level of commercial viability, but there is currently recognition of the need for AUV, and an expectation of increased benefit from using these vehicles. In order for AUV to be firmly established as a viable, mature technology there are several issues that need to be addressed, not the least of which is reliability. A systematic study was made involving simulations of a vehicle under fault conditions to identify the vehicle behaviours typical of such fault conditions. The simulation tool used is a linear model of the dynamics of the Canadian Self-Contained Off-the-shelf Underwater Testbed (C-SCOUT), and the maneuvers used were those most likely to be desired during normal operation; holding course, a controlled dive, and a turn in the horizontal plane, C-SCOUT is typical of many cjurrent AUV, therefore the results of the study are appplicable in a qualitative sense to a number of vehicles.NRC publication: Ye

AUV controllability with control plane faults

It may be important to be able to operate an autonomous underwater vehicle (AUV) when it has reduced control authority due to a control plane fault, such as a jammed or a missing control plane. Knowledge of how the vehicle behaves under these conditions will allow the mission planner to make critical decisions about the viability of the mission or about certain specific subtasks. Knowledge of vehicle behaviours under fault conditions can also facilitate the use of operational envelopes in restricted waters; i.e. a healthy AUV may be restricted in the magnitude of control plane deflections, so that it can maintain a safe trajectory even if a control plane fails. A systematic study was made involving simulations of the vehicle under fault conditions to identify the vehicle behaviours typical of such fault conditions. The simulation tool used is a linear model developed from a fully nonlinear model of the Canadian Self-Contained Off-theshelf Underwater Testbed (C-SCOUT), and the manoeuvres used were those most likely to be desired during normal operation: holding course, a controlled dive, and a turn in the horizontal plane. The fault condition simulations provide useful information, especially concerning safe operating envelopes for the CSCOUT for particular mission requirements. The information can also be used to enable the vehicle to perform selfdiagnosis procedures under some conditions.NRC publication: Ye

Modeling of an autonomous underwater vehicle

The Canadian Self-Contained Off-the-Shelf Underwater Testbed, or C-SCOUT, is an autonomous underwater vehicle (AUV) designed and built by graduate students at Memorial University of Newfoundland and work term students employed by the Institute for Marine Dynamics. The AUV is part of the NSERC strategic grant: Offshore Environmental Engineering Using Autonomous Underwater Vehicles. The project applies the vehicle technology to the problem of environmental monitoring of offshore oil production facilities. Future variations of the AUV can be configured for a wide variety of missions including search and survey, under ice operations, iceberg profiling, oceanographic sampling, and mine detection and countermeasures.NRC publication: Ye

Autonomous vehicle systems research at National Research Council Canada, Institute for Marine Dynamics (NRC-IMD)

This paper provides general information on autonomous systems (vehicles) that operate in water, on land, in air and in space. The associated ideas lead directly to considerations that affect the design of fully-autonomous vehicles. We include a discussion of some of the engineering, logistical and systems-integration aspects of autonomous operations, including the use of multiple vehicles in a coordinated "fleet". We outline some of the technical challenges associated with working within a limited energy budget and mention some possible strategies for vehicle-to-vehicle communications and for vehicle-network configurations and management. The results from this research will permit planners and developers of autonomous vehicle systems to better allocate such limited assets in order to provide more effective operations in hazardous environments. We describe the design of one instance of such a vehicle, in the form of a highly-manoeuvrable autonomous underwater vehicle (AUV). We go on to describe our initial successes and lessons learned, and, our plans for subsequent development of the AUV and its role as a prototype member of small a "fleet" of AUVs. We describe some parallel work-in-progress (with a single AUV) that has commercial application in support of the Canadian East Coast offshore oil and gas industry. This work involves the AUV carrying suitable sensors to detect and quantify the presence of certain chemicals in ocean water samples. Current and future results from our research can be generalized to more effective operations of autonomous vehicles on land, in the air and oceans, and in spaceNRC publication: Ye