1. Water-fall: traditional, >80%, ord eng.
req analysis (>30%): specification; needs/constraints/$$/deadline/reliability/size
investigation: concept exploration,
meetings, feasibility, finance
30 cities, travel once minimal Hamilton circle, NP-hard
mutual misunderstanding: replace(put it back) the handle in gas station; “I have a lamb”:
I have a lamb. 1 food; 2: pet; 3: nice husband/guy; 4: Lamb..—$$ car!
solutions:
0. more NL
1. use logic description, math: universal language
2. diagram/graph/visualization tools;
3. prototype: simulation sw/hw, simulink, python/matlab prototyping pl, sql

2. Why software development difficult/different MIS,
lack of visualization: moving targets,
between se. communications, specification: ph1 report
Design: 2 levels: Architecture/high-level: modules/classes and detail/low-level design: alg+data struct (=program)
modules + comm; ds + logic/alg: each module
alg, math: difference equation: discrete version of differential eq/ math/modeling
Coding/implementation phase: understandable, clean logic, swimming and integration: deliver prod
Testing + integration: alpha/beta
Maintenance: customer/huge
SQA: system quality assurance team Toyota ()
Sys an>plan>design….
pros and cons:
quality, documentation, strict discipline; SQA
Cons: time/$ consuming; lack of comm; big overall risk; miss target
Rapid prototyping: quickly build summarizations reflect main func in order to communicate with clients/peers embedded in wf model
pros: better comm; better response/feedback
cons: invite more moving targets, crucial features may not be there