Lesson 9

Levels of Failure:

• Physical, Process, Attitudes

Apply Hazard and Operability Sutdy, Hazards Analysis, Fault Tree Analysis, Failure models and effects analysis, and Ishikawa diagrams

Failure analysis is post-failure forensics

Hazard analysis is pre-failure/preventative analysis to avoid potential disasters - expect the unexpected

Types of Data Analysis

Diagnosis

• Desriptive - hindsight (what happened?)
• Diagnostic - insight (why did it happen?)

Prognosis

• Predictive - foresight (What could happen?)
• Prescriptive - oversight (What needs to happen?)

Levels of Failure

One - physical flaws (mostly mechanical engineers)

Two - process (hits us the most out of the 3)

Three - perspective or attitude

PHysical flaws

• Metal fatirue
• corrosion
• toxicity
• electrical faults (short circuit)

Process

• If formulate a problem wrong, the solution will most likely be wrong
• Errors in manufacturing, assembly, judgement
• Errors in packaging
• Design and implmentation based on invalid assumption
• Bad calculations (Think Mars Climate Orbiter)

Perspective or Attitude

• Trust me, I'm always right

Ask Five Whys

Why? Battery dead

Why? Alternator not functioning

Why? Alternator belt broken

Why? Alternator belt beyond useful service life

Why? Vehicle not maintained according to recommendation service schedule

Root Cause Analysis (RCA)

Method to identify root causes of faults or problems in four steps

• Identiy and describ eproblem
• Establish timeline from normal situation up to problem time
• Distingh root cause ando toher causla factors such by eg using event correlation
• Establish causal graph between root cause and problem

Toyota Way (Toyoda?)

14 Principles in four sections

Base management decisions on long-term philsophy at expense of short-term financial goal

Standardize task and process are foundaation for continuous improvement (kaizen) and employee empowerment

Build culture to fix problems and get quality right the first time

heijunka kaizen genchi genbutsu nemawashi hansei

A3 problem solving

A3 paper size is size of the table

Tabular form, identify things like name, leader, stakeholders, etc.

Specify problem, root cause, breakdown, etc.

Helps solve problems

Fault Tree ANalysis(FTA) (top down)

a bunch of symbols

FMEA - bottom up

Walter A. Shewhart (Bell Labs)

Father of control chart and statistical process control to identify outliers and did further

W. Edwards Deming

Took Shewhart's process and introduced it to lecture he gave in Japan

"If you can't describe what you are doing as a process, you don't know what you're doing."

"It is not enoguh to do your bets; you must know what to do , and then do you rbets."

When Japanese find something good, they will make it the best.

Kaoru Ishikawa

Plan Do Check Act (Deming) into six steps

• determing goals and targets
• determin methods of reaching goals
• engagae in educationa nd trainign
• implement wokr
• chck effects of implementation
• take appropriate cation

Seven basic tools of quality

• check shet
• control chart
• striatificaiton
• pareto chart
• historgram
• cause-and-effect diagram

scatter diagram

Standards not the ultimate source

Ishikawa (Fishbone) Disagnostic Diagram

• More formal Why Why diagram
• Beoing, Samsung

Zipf's Law (1935)

harvard uni prof, linguist

Mathematical model, log-log is straigh tline

Discrete Pareto distribution

Vilfredo Pareto

Italian civil engineer

Pareto distriution which is power law probability distribution

80/20 rule (80% of land owned by 20% of population)

Pareto chart is special type of histogram used to view causes of a problem in order of severity from largest o smallest

Six sigma

registered trademark and service mark fo motorola

Six Sigma process improvement efforts, defects per million opporunities

Specification lmits (USL and LSL) are distance 6sig from mean

Even if mean move lft or right by 1.5sig, there is good safety cushion

Methodloogies (six sigam)

DMAIC improve existing business processes

• Define
• meausre
• analyze
• improve
• control

DMADV creat new product or process designs

• define
• maeasure
• analyze
• design
• verif7

Capability Maturity Model Integration (important for sofwater engineer)

Carngeie Mellon University

5 levels

5 - optimizing focus on process imporvoement

4- quantitiavile managed process mesausred and controlled

3- defined process characterized for the organization and is proactive

2-managed processes characterized for projects often reactive

1- intiial process unpredictable poorly controoleed

Dealing with hazards (5 steps)

NEC (national electrical code) prevents fire

National Electrical Safety Code is about user safety (ANSI Standard C2)

Motor Vehicle Safety Standards (eg antilock brakes, seatbelt, airbag)

Regrettable inventions

Did not know about lead in gasoline, CFCs in refrigerants, propellants in aerosol applications

Jeff Bezos

Idea -> When I'm 80 will I regret not doing it -> No let it go, yes do it

He's no longer WallStreet trader

Circular Economy

we want to reuse

Hazard Avoidance

Use guards, sensors, interlocks, and other metchanisms to distnace user form hazard

• Avoid malware by not clicking links

Redundancy, backups, etc.

Safety signs as opposed to warning signs

SecDevOps (Secur DevOpment) best practices

plan code build test release deploy operate monitor repeat

Chaos Engineering

Experimenting on software system in production to build confident in system's capabilities to withstand turbulent and unexpected conditions

Simian Army is suite of tools by Netflix to test reliability security etc of its AWS infrastructure

Chaos Monkey 2011 to test resilience of IT infrastructure

10-18 monkey detetct problems with local/internationalization (l10n-i18n)

Why monkey? Because they usually have smiley face and han dout banana on street to promote AWS

Geohazards

Zoombombing

OSHA