Introduction to Lung CT AI

AI: An Intelligent Agent

The foundation for this book about lung CT AI is the application of what Alan Turing described in 1936 as the “universal Turing machine.” This is what is known today as the computer hardware and software that dominates so much of our lives, and is at the heart of lung CT AI. In his recent book, Stuart Russell describes succinctly what Alan Turing meant by the universal Turing machine. The essence of Turing’s discovery was to define two new mathematical objects. The first was defined as a machine, what is known today as computer hardware. The second, mathematical object, Turing defined as a program that is known as software code that runs on the computer hardware. Together, the machine (computer hardware) and the program (software code) define a sequence of events, or a sequence of state changes, that occur in the machine (computer CPU, computer memory, etc.) to accomplish a task.

Russell describes the key concept in modern artificial intelligence (AI) as being the concept of an intelligent agent. The intelligent agent exists in the software programs running on a computer. How the AI agent is built depends on the objective(s) to be achieved or the problem(s) to be solved. The functioning AI agent then depends on four important things: (1) environment; (2) observations; (3) actions; and (4) objective(s) ( Fig. 1.1 ). The environment is the physical and electronic space that the AI agent can access. Using the word processing (WP) AI agent as an example, the WP AI agent environment includes keyboard commands, computer display, and computer hardware and software, as well as any internet connections that are running. The observations that the WP can make are the keystrokes pressed, and it can read the WP files that exist on the computer and in the cloud. The actions that the WP can take are: recording the keystrokes and displaying those on the screen; storing them on the computer or the Internet; and reading and writing existing WP files from the computer memory, hard disk drive, and the Internet ( Fig. 1.2 ). The objectives for the WP AI agent are determined by the people who wrote the software to run on the computer. These objectives can be summarized as taking keystroke inputs and creating a software file that records the keystrokes and displays them on the computer screen. It is also important to recognize that one AI agent can pass the objectives to another AI agent to perform additional objectives, and this process can continue with as many AI agents as desired. For example, the WP files on a computer can be sent to a typesetting program that a publisher would use to generate the final output for a book.