'2024/03/25 글 목록

2024/03/25 8

S chart 는 언제 쓰면 될까 ? 1) Sample size 'n > 10' 일 때 ( n이 10보다 작거나 같을 경우 R 차트를 사용하는것이 좋다) 2) Used for variable sample size => Subgroups have different sample size 1. X bar and S control chart with variable sample size (subgroup의 sample size가 다를 경우) m : # of samples/ subgroups ni : sample size for each samples/ subgroups * 각 subgroup의 sample size가 다르지만 , 하나의 고정된 컨트롤 리밋으로 작성하고 싶을 경우에는 ni의 평균을 사용하거나 가장..

산업공학/Manufacturing 2024.03.25

Control Chart for x_bar and R

컨트롤 차트 , X_bar and R - Suppose (xij, i=1..m j=1..n} are normally distributed - X bar chart monitors between-sample variability (variability over time) X bar 차트는 샘플들 간의 변동성을 나타내고 R chart measures within-sample variablitiy (intantaneous variability at a given time) R 차트는 샘플내의 변동성에 대해 측정한다. 1. Control chart for X_bar and R - Known μ and σ - Range Ri = max (x_ij) - min (x_ij) for j=1.. n - μ and σ을..

산업공학/Manufacturing 2024.03.25

Root Cause Analysis

* Root and Cause Analysis , Continuous Improvement - To prevent recurrence at lowest cost in the simplest way 발본색원의 개념, 근원이 되는 문제를 제거해서 비슷한 문제들이 다시는 발생하지 않도록 방지하는 것 - method to trace down RC: data mining hierachial cluster solution (GT data mining) 1) Root cause: removed; prevent undesireable outcome,the condition that enable one or more causes 2) Casual cause: affect an event's outcome, but not..

산업공학/Manufacturing 2024.03.25

Dissimilarity Matrix

- Dissimilarity Matrix (n objects x p attributes) : Store a collection of proximities that are available for all pairs of n objects A triangular matix, i.e., d(i,j) = d(j,i) d(i,j) is the measured dissimilarity or "differce" between objects i and j similarity measure sim(i,j) = 1 - d(i,j) d(i,j) is a non-negative number that is close to 0 when objects i and j are highly similar or "near" each ot..