Biomedical Engineering Reference
In-Depth Information
Some of the research areas in the field of AI today include web search engines, knowledge
capture, representation and reasoning, reasoning under uncertainty, planning, vision, robotics,
natural language processing, and machine learning. Increasingly, AI components are embedded
in devices and machines that combine case-based reasoning and fuzzy reasoning to operate
automatically or even autonomously. AI systems are used for such tasks as identifying credit
card fraud, pricing airline tickets, configuring products, aiding complex planning tasks, and
advising physicians. AI is also playing an increasing role in corporate knowledge management,
facilitating the capture and reuse of expert knowledge. Intelligent tutoring systems make it possible
to provide students with more personalized attention or even have computers listen and respond to
speech-provided information. Moreover, cognitive models developed by AI tools can suggest
principles for effective support for human learning — guiding the design of educational systems
(Russell and Norvig, 2003).
1.5 NATURE AS A MODEL FOR STRUCTURES AND TOOLS
Biological creatures can build amazing shapes and structures using materials in their surroundings
or the materials that they produce. The shapes and structures produced within a species are very
close copies. They are also quite robust, and support the required function of the structure over the
duration for which it is needed. Such structures include birds' nests and bees' honeycombs. Often
the size of a structure can be significantly larger than the species that built it, as is the case of the
spider web. One creature that has a highly impressive engineering skill is the beaver, which
constructs dams as its habitat on streams. Other interesting structures include underground tunnels
that gophers and rats build. Birds make their nests from twigs and other materials that are secured
to various stable objects, such as trees, and their nests are durable throughout the bird's nesting
season. Many nests are hemispherical in the area where the eggs are laid. One may wonder
how birds have the capability to design and produce the correct shape and size of nests that
matches the requirements of allowing eggs that are laid to hatch and grow as chicks until they
leave the nest. The nest's size even takes into account the potential number of eggs and chicks, in
terms of required space. Even plants offer engineering inspiration. Velcro was invented by
mimicking the concept of seeds that adhere to an animal's fur, and has led to an enormous impact
in many fields including clothing and electric-wires strapping. Because of their intuitive charac-
teristics, the use of biologically based rules allows for the making of devices and instruments that
are user-friendly and humans can figure out how to operate them with minimal instructions.
Examples of devices and structures that were most likely initiated from imitation of biological
models are listed below. These examples illustrate the diverse and incredible number of possibil-
ities that have already been biomimicked.
1.5.1 Constructing Structures from Cells
Using cells to construct structures is the basis of the majority of animals and plants. Adapting this
characteristic offers many advantages including the ability to grow with fault-tolerance and self-
repair. Advances in nano- and micro-technologies are allowing the fabrication of minute elements
that could become the basis for making artificial cells. Recently, scientists from the University of
Washington, Seattle (Morris et al., 2004) reported on the use of guided and unconstrained self-
assembled silicon circuits to constructed micro-electro-mechanical systems (MEMS)-based cells
that can potentially have this capability. The term
self-assembly
is defined as the spontaneous
generation of higher-order structures from lower-order elements. Self-assembly is the basis of the
structure for all biological organisms, which exhibit massively parallel fabrication processes that
generate three-dimensional structures with nanoscale precision. As a result, many orders of
magnitude are spanned from the elemental or device-size scale to the final system level. This
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