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Ultrasound Physics
Published in Debbie Peet, Emma Chung, Practical Medical Physics, 2021
Medical ultrasound technology was developed following the Second World War based on Sound Navigation Ranging (SONAR) methods developed for detecting submarines. In SONAR, a “ping” of sound is emitted, and an echo intensity map is then generated by analysing the direction, intensity and timing of the resulting echoes. This uses the same principle of echolocation that bats and dolphins use naturally to navigate their surroundings. As the speed of sound in water is known, measuring the time taken for echoes to return to the transducer, makes it possible to plot echo intensities as a function of depth (Figure 3.2).
Intelligent Algorithms for the Diagnosis of Alzheimer’s Disease
Published in Abdel-Badeeh M. Salem, Innovative Smart Healthcare and Bio-Medical Systems, 2020
Sarah A. Soliman, Rania R. Hussein, El-Sayed A. El-Dahshan, Abdel-Badeeh M. Salem
Some bats use echolocation to some extent; microbats are a famous example among all species as they make extensive use of echolocation, while megabats do not. Insectivores are the majority of microbats. Microbats use an echolocation type of sonar to track predators, avoid obstacles, and locate their roosting crevices in the night. These bats emit a very loud pulse of sound and listen to the echo that bounces back from the artifacts around. Their pulses vary in characteristics and depending on the species can be correlated with their hunting strategies. Most bats use short, frequency-modulated signals to sweep around an octave; others use echolocation signals with constant frequency more frequently. Their amplitude of the signal varies with species and often decreases with more harmonics. Studies have shown that microbats use the time delay from echo emission and detection, the time difference between their two ears, and the echoes’ loudness differences to create a three-dimensional surrounding scenario. They can detect the distance and orientation of the target, the type of prey, and even the moving speed of the prey, such as small insects [97, 98].
7.00: Listening and looking
Published in Fiona Broadley, Supporting Life Skills for Young Children with Vision Impairment and Other Disabilities, 2020
You can further develop echolocation by singing or chattering into a bucket and pointing out how different it sounds. If you want to find out more about the use of echolocation for navigation, investigate the works of Daniel Kish (https://www.abc.net.au/btn/classroom/bat-man/10533060, https://worldaccessfortheblind.net/facilitating-movement-and-navigation-blind-pre-schoolers-positive-practical-approach). He encourages using echolocation, which he calls Flash Sonar, for those with vision impairment. Not everyone can use it to this level, but it can be a very useful skill when combined with other skills and strategies.
Equipment factors affecting identification of water level with echo for the blind
Published in Assistive Technology, 2020
Changes in water level when pouring water may cause different echoes. An echo is a sound that reflects back from an obstacle. Detecting nearby obstacles with echo is called echolocation. Echolocation adopt three successive types of sound, namely direct sound, superimposed direct and reflected sound, and reflected sound. (Rowan et al., 2013). The object size, distance, material, shape, and other information can be calculated from the relationship between direct sound and reflected sound. Larger and closer obstacles reflect back more sound, due to the larger area that reflects more echoes (Rice & Feinstein, 1965) . The distance to the obstacle also influences both loudness and pitch of echo, where the echoes reflected from closer obstacles are higher in pitch (Bilsen, 1966; Yost & Hill, 1978) and louder (Stroffregen & Pittenger, 1995). Softer materials absorb higher frequencies, so reflected sounds are lower than the direct sounds (Stroffregen & Pittenger, 1995). Echoes generated from pouring water can be employed to derive the water level.
Minimal selfhood
Published in Journal of Neurogenetics, 2020
To be sure, this is consciousness at its most basic. More complex selves may be endowed with modes of perception at a distance, such as vision. Optical apparatus and image-forming systems such as the echolocation of toothed whales and bats enable an animal to ‘visualize’ its goal as the endpoint of a trajectory, a target within a framework or context. By contrast with taste or olfaction, this opens up a world of spatial extension and three-dimensional depth. A further, major step towards a more flexible cognitive relationship to the world involves an inner ability to ‘represent’ some feature of it (such as our food or a mate) in its absence. This enables a hungry self to continue a pursuit or search even when its objective has momentarily eluded its sensory range, remembering where this objective was and possibly predicting where it soon will be. An implicit sense of time in turn provides a framework for foresight as well as memory. The exercise of self-restraint – the refusal of an immediate reward in anticipation of a larger reward for having held back – presupposes some sort of capacity to represent a treat yet to come. Well attested among mammals and birds, this ability to ‘defer gratification’ testifies to the increasingly sophisticated manifestations of consciousness with which more complex animals are endowed. Anticipating the future, they now have the option of acting in accordance with longer-term interests. These more flexible forms of consciousness in turn lay the foundations for the autobiographical or narrative self-awareness that distinguishes humans.
Rehabilitation in the real-life environment of a shopping mall
Published in Disability and Rehabilitation, 2018
Delphine Labbé, Tiiu Poldma, Catherine Fichten, Alice Havel, Eva Kehayia, Barbara Mazer, Patricia McKinley, Annie Rochette, Bonnie Swaine
The mall was described as a controlled environment, facilitating mall use during rehabilitation because it minimized clients’ stress. In fact, according to the participants, the mall represented the right compromise between the rehabilitation center, an environment where almost everything is controlled, and the outdoor environment (e.g. the streets) where there are many uncontrollable variables (e.g. pedestrians and vehicle traffic, maintenance/state of the pavement, Canadian winters, etc.). “It allows one to be more efficient in a way, when you have specific goals, whether it rains or it snows. It’s more controlled” (P2, Occupational therapist). For people with visual impairments, the controlled environment of the mall could also facilitate the training of echolocation skills for orientation, because the walls and openings can be perceived more easily than in other environments.