FE Industrial & Systems flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Central Limit Theorem

For independent samples of size n ≥ 30, the sample mean is approximately normally distributed with mean μ and standard error σ/√n, regardless of the population's shape.

Poisson distribution

Models counts of rare events in a fixed interval when events are independent, with P(X = k) = e^(−λ)·λ^k/k!; the mean and variance both equal λ.

Coefficient of determination

R², the proportion of total variation in the response explained by the regression model; it equals SSR/SST and ranges from 0 to 1.

Type I error

Rejecting a true null hypothesis, which occurs with probability α, the significance level; it corresponds to producer's risk in acceptance sampling.

Capital recovery factor

(A/P, i, n) = i(1+i)^n/[(1+i)^n − 1]; it converts a present sum into an equivalent uniform annual series over n periods at rate i.

Internal rate of return

The interest rate that makes a project's net present worth equal zero; the project is acceptable when the IRR is at least the MARR.

Straight-line depreciation

Annual depreciation equals (first cost − salvage value)/useful life, so book value decreases by a constant amount each year of the asset's life.

Public welfare paramount

The fundamental canon of engineering ethics: engineers shall hold the safety, health, and welfare of the public paramount in all professional activities.

Conflict of interest

A circumstance in which professional judgment could be swayed by personal gain; engineers must disclose it and avoid serving two parties on the same matter.

Seal and signature

Engineers may seal or sign only documents prepared by them or under their direct supervisory control, never work they have not reviewed.

Little's Law

Work-in-process equals throughput multiplied by flow time; it holds for any steady-state system, so reducing flow time lowers WIP at constant throughput.

Overall equipment effectiveness

OEE = availability × performance × quality, where each factor is the actual value divided by the ideal value; world-class performance is often cited near 85%.

Takt time

Available production time divided by customer demand over the same period; it sets the pace a line must meet to satisfy demand exactly.

Economic order quantity

EOQ = √(2DS/H), the order size that minimizes the sum of ordering and holding costs; at the optimum the two cost components are equal.

Reorder point

The inventory level at which a replenishment order is placed: demand rate times lead time, plus safety stock when demand or lead time is uncertain.

Johnson's rule

A sequencing rule minimizing makespan for jobs run through two machines in the same order: take the shortest time, schedule early if on machine one, late if on machine two.

Systematic Layout Planning

Muther's procedure: analyze flow and activity relationships, build a relationship diagram, determine space requirements, then generate and evaluate block layouts.

Line balancing cycle time

Available time per period divided by required output; no workstation may be assigned a combination of tasks whose total time exceeds this cycle time.

Center-of-gravity method

A facility location technique weighting each existing site by its volume: x* = Σwᵢxᵢ/Σwᵢ, with y* computed the same way.

NIOSH lifting equation

Recommended weight limit = LC × HM × VM × DM × AM × FM × CM; the lifting index is the load divided by the RWL, and values above 1 signal increased risk.

Fitts' law

Movement time to a target follows MT = a + b·log₂(2D/W), so larger targets and shorter distances produce faster and more accurate pointing.

Anthropometric percentile design

Design to the 5th percentile where reach is the limiting factor and to the 95th percentile where clearance is limiting, so most users are accommodated.

Process capability index Cpk

Cpk = min[(USL − μ)/3σ, (μ − LSL)/3σ]; it accounts for process centering and should reach at least 1.33 for a capable process.

Taguchi loss function

L(x) = k(x − T)², expressing that any deviation from the target value T incurs a cost that grows quadratically with the size of the deviation.

Average outgoing quality limit

The maximum average fraction nonconforming that leaves inspection, taken over all possible incoming quality levels, for a given sampling plan.

M/M/1 queue length

For one server with Poisson arrivals and exponential service, L = ρ/(1−ρ) and Lq = ρ²/(1−ρ), where utilization ρ = λ/μ.

Shadow price

The marginal change in the optimal objective value per unit increase in a constraint's right-hand side; it is zero when the constraint has slack.

Critical path

The longest path through the project network; its length determines the project duration, and activities on it have zero total slack.

Expected value of perfect information

The expected payoff with perfect information minus the best expected monetary value without it; the maximum a decision maker should pay for that information.

Earned value cost performance index

CPI = earned value / actual cost; a value below 1 means the project has spent more money than the value of work completed.

Series system reliability

For independent components arranged in series, R = R₁ × R₂ × … × Rₙ, so system reliability is always lower than the weakest single component.

Functional baseline

The approved requirements and performance specification established at the end of concept development; changes to it require formal configuration control.