Abstract: A computer-implemented method of evaluating the performance of a trajectory planner for a mobile robot in a real or simulated scenario, comprises receiving scenario ground truth of the scenario, the scenario ground truth generated using the trajectory planner to control an ego agent of the scenario responsive to at least one scenario element of the scenario. One or more performance evaluation rules for the scenario and at least one activation condition for each performance evaluation rule are received. A test oracle processes the scenario ground truth to determine whether the activation condition of each performance evaluation rule is satisfied over multiple time steps of the scenario. Each performance evaluation rule is evaluated by the test oracle, to provide at least one test result, only when its activation condition is satisfied.

Abstract: An ultrasonic sonar transducer (10) for facilitating transmission and reception of sonar signals, particularly at high speeds. The sonar transducer includes a transducer element (12) and a transducer housing (14). The housing includes a bottom wall (34) that is continuously curved with no major portion thereof parallel to the bottom face of the element. The bottom wall has a recessed portion (40) that partially forms an acoustic window for facilitating the transmission and reception of acoustic energy, with the acoustic window having a thickness approximately equal to one half or an integer multiple of one half of the wavelength of the acoustic energy. The bottom is preferably bow-shaped to create a positive angle of attack relative to the oncoming water, thereby promoting a laminar flow that reduces turbulence and cavitation and therefore nearly eliminates undesirable attenuation and reflection of transmitted and received energy.

Abstract: A cover is provided for an end of a conduit. The cover comprises a front face covering the conduit end and a back face having fasteners for attachment to a conduit. A plurality of apertures pass between the front face and back face to allow the flow of liquid to and/or from the conduit. The edges of the front face defining the entrances to the apertures are non-planar. In addition to, or as an alternative to, the apertures are formed such that the flow of liquid between the front and back faces is deflected so that the liquid follows at least two directions in passing between the front and back faces. The cover can be used as a grille over drainage in a swimming pool.

Abstract: An ultrasonic sonar transducer (10) for attachment to a water vessel that more effectively transmits and receives sonar signals even when the water vessel is traveling at high speeds. The sonar transducer includes a transducer element (12) and a transducer housing (14) for housing the transducer element. The transducer housing includes a lower housing section (22) having a bottom wall (34) that is continuously curved with no major portion thereof parallel to the bottom face of the transducer element. The curved bottom is preferably bow-shaped so that the front of the transducer housing is raised relative to the rear to create a positive angle of attack relative to the oncoming water. This pressurizes water flow under the bottom of the transducer housing and promotes a laminar flow. Such a laminar flow reduces turbulence and cavitation and therefore nearly eliminates undesirable attenuation and reflection of transmitted and received energy.

Abstract: A cover means (2) is provided for an end of a conduit (9). The cover means comprises a front face (4) covering the conduit end and a back face (6) having attachment means (8) for attachment to the conduit (9). A plurality of apertures (10, 12, 14) pass between the front face (4) and back face (6) to allow the flow of a liquid to and/or from the conduit (9). The edges of the front face defining the entrances to the apertures (10, 12, 14) are non-planar. In addition to, or as an alternative to, the apertures (10, 12, 14) are formed such that the flow of liquid between the front and back faces is deflected so that the liquid follows at least two directions in passing between the front and back faces.