## Midterm Exam 1 Review Fall 2003: CS concepts

(Back to Fall2003 Midterm Review 1)

fourier transform -A Technique for expressing a waveform as a weighted sum of sine's and cosines. It includes the analysis and compression of video and sound information.

algorithm – a small procedure or formula that solves a recurrent program

hierarchical decomposition – ????

encoding- the activity of converting from plain text into code.

REMOVEDs law- the number of transistors per square inch on integrates circuits had doubled every year since the integrated circuit was invented, data density has doubled approximately every 18 months. It will eventually slow down, but expected to last for another 2 decades.

hierarchical decomposition - breaking up a function into smaller functions, so they do one and only one thing? Like sunset being broken into decreaseBlue and decreaseGreen - I'm not sure about this answer

 Nice answer on hierarchical decomposition, but think about "problems" being broken down until you CAN write a "function." Do you really understand the answer above on Fourier transform, algorithm, and REMOVED's Law? What are each good for? What are their implications? Mark Guzdial

REMOVEDs law- the number of transistors per square inch on integrates circuits had doubled every year since the integrated circuit was invented, data density has doubled approximately every 18 months. It will eventually slow down, but expected to last for another 2 decades. So the number of transistors would double at the same price every 18 months, effectively meaning that the same amount of money would buy twice as much computing power every 18 months
"nina barlin"

encoding- the activity of converting from plain text into code. The computer has a memory filled with bytes, everything that a computer is working with at a given instant is stored in its memory. That means that everything that a computer is working with is encoded in its bytes, jpeg pictures, excel spreadsheets, word documents, spams etc. computers can layer encodings to virtually any level of complexity.
Algorithm – How a recipe works, completely apart from how its written Is called the study of algorhithms, its a small procedure or formula that solves a recurrent program
good enough????
nina

Nina: you are on the right track, but with REMOVED's law, is there a REMOVED general rule of thumb that can be applied to technology rather than just the number of transistors and data density? Can we use this rule to estimate where computers may be in a few years?Brittany Selden

 Nina did get REMOVED's Law – that essentially we double the amount of computing power per dollar every 18 months. On encoding: Very close. It's not that plain text gets mapped to code – it's that everything gets mapped to bytes! Nice one on Algorithms. Anyone for hierarchical decomposition? Mark Guzdial

Heirarchical decompositition is the process of taking a problem and breaking into its smaller components that you can then address. So if I decomposed, say 'make a skyscraper' I would then have problems like 'pour foundation,' 'erect framework,' 'install HVAC,' 'install electrical,' and so on. I can then write processes, or algorithms, to solve the smaller problems, and then combine them to erect the skyscraper.

Interesting analogy... good way to remember it.

Student549