Digital Signal Processing: Functions and Implementations
Impulse Response
n =- 10:1:30; b = [-1 2 3 6 ...]; A = 1, x = zeros (1,41), x (11) = 1, y1 = filter (B, A, x), stem (n, y1), grid;
Zero-Pole Plot (Zerpol)
function [zeros, poles] = zerpol (B, A); bs = roots (B), as = roots (A); zeros = bs; poles = as; polar (angle (bs), abs (as), 'x') hold off;
Frequency Response (Respfrec)
function [module, phase, frequency] = respfrec (B, A, nfrec) linespace frequency = (0,0.5, nfrec), b = B (length (B): -1:1); a = A (length ( A): -1:1); polyval numerator = (b, exp
Computer Systems and Network Security Essentials
Why Aren’t All Computer Systems Secure?
- Cost/Benefit Issues
- Security Costs
- Users perceive no personal threat to themselves
- Ignorance
Legacy and Retrofitting
- We are constrained by legacy issues:
- Core Internet design
- Popular programming languages
- Commercial operating systems
- All developed before security was a concern
- Retrofitting security works poorly
Problems With Patching
- Usually done under pressure:
- So generally quick and dirty
- Tends to deal with obvious and immediate problem:
- Not with underlying cause
- Hard
Phonetics: Syllables, Consonants, and Pronunciation
Syllables
A syllable is a unit of organization for a sequence of speech sounds. A syllable is made up of a syllable nucleus (most often a vowel) with optional initial and final margins (typically, consonants). The parts are onset and rhyme; within the rhyme, we find the peak (normally a vowel) and coda (any consonants following the peak). Not all syllables have all parts. The smallest possible syllable contains a nucleus only. A syllable may or may not have an onset and a coda.
- Onset: Any consonant
Econometric Data Analysis: Types, Models, and STATA Commands
Econometric Data Types
- Cross-sectional: Samples at a given point in time or current period.
- Time series: Variables over time; the ordering of observations is important.
- Pooled cross-sectional: Two or more cross-sections are combined, e.g., comparing variables across two different years. Used to evaluate policy changes.
- Panel/Longitudinal data: The same cross-sectional units are followed over time. Can be used to account for time-invariant unobservables. E.g., each city has two observations in two different