1
IE 368: FACILITY DESIGN AND
OPERATIONS MANAGEMENT
Lecture Notes #5
Introduction to Facilities Layout
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Facilities Layout
2
 Facilities layout is a design activity and as such there
is often a lot of art (i.e., experience) and applicationspecific knowledge that must be utilized when
developing a layout




Grocery store layout vs. department store layout
Layout of an engineering complex
Layout of an educational/research building
Layout of plants that produce different products
• Vehicle vs. computers
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Facilities Layout (cont.)
3
 There are no
recipes for the layout
 In reality, politics and other organizational
considerations will place constraints on layouts
 All material presented related to layout design is
decision support
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Facilities Layout (cont.)
4
 Information needed to design a layout
1. What are the “blocks” or departments that constitute units or areas
within a layout?
2. Building/facility footprint
• Exits/entrances/docks, etc.
• Columns, ceiling height, location of utilities.
• Other?
3. Flow measurement/Adjacency measurement
4. Space requirements
• Departments
 Workstations, aisles, storage, meeting rooms, etc.
• Central storage
• Administration
• Etc.
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Units or Areas Within a Layout
5
 Normally this is given as input data
 Often will follow organizational and/or production system
structure
 Examples
 Engineering complexes – Various product development
departments are given
 Batch production system – Sheet metal press lines
• Various press line sizes are given
 Support functions must be included
 Storage, admin/engineering offices, IT support, cafeterias,
lockers, restrooms, conference rooms, etc
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Building Footprint
6
 Often also given as input data
 Items of particular concern that affect flow in a
facility




Location of shipping/receiving docks
Location of entrances/exits
Columns
Ceiling heights
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Facilities Layout
7
 Measuring flow
 Quantitative
• Appropriate when large volumes of material/people move between
departments
 Qualitative
• How important is adjacency to two departments?
• Often applied to the layout of office environments
 Other types of flow?
 Sound
 RF signals
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Quantitative Flow Measurement
8
 Captured in a From-To chart
 Units are the number of trips of equal ease of
movement per time unit
 e.g., moving a large die is much more effort than moving a
small bin of parts
From
Stores
Milling
Turning
Press
Plate
Assembly
Warehouse
To
Stores
X
Milling
12
X
3
Turning
6
Press
9
X
X
3
1
1
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
Plate
1
7
4
3
X
Assembly
4
2
1
4
X
Warehouse
1
3
7
X
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Quantitative Flow Measurement
(cont.)
9
 Terminology
 From-To chart
• Symmetric travel paths are not necessarily assumed
 Flow-Between chart
• Assumes symmetric travel so that only the upper or lower portion
of the chart is needed
 Only the total flow (in either direction) is needed
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Construction of the Charts
10
1. List departments in rows and columns according to
the general flow of jobs
• Helpful but not critical to list in this order
2. Translate movements of different jobs/items into
equivalent materials handling moves
3. Translate production quantities/routings into
materials handling moves between departments
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Example 3.4
11
 A firm produces three components. Components 1 and 2 have the same
size and weight and are equivalent with respect to movement.
Component 3 is almost twice as large and moving two units of
components 1 or 2 is equivalent to moving one unit of component 3.
The departments included in the facility are A, B, C, D, and E. The
overall flow path is A-B-C-D-E. The quantities to be produced and the
component routings are as follows:
Production Qty.
Component
Per Day
1
30
2
12
3
7
Routing
A-C-B-D-E
A-B-D-E
A-C-D-B-E
 Construct a From-To chart
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Example 3.4 – Solution
12
A
A
B
B
C
D
E
---
C
D
E
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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In-Class Exercise
13
 Suppose containers are moved one at a time
 Produce a from-to chart with the number of moves between
departments per week
 Suppose moves of containers for product 1 and 2 have a fixed cost of
$5 per move and moves of containers for products 3 and 4 cost $1
per move
 Create a from-to chart with material movement cost per week
Product
1
2
3
4
Routing
A-B-C-D-E
A-D-E
A-B-C-E
A-C-D-E
Production Qty.
Per Week
200
900
400
650
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
Container
Size
50
10
25
50
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In-Class Exercise (cont.)
14
A
A
B
C
D
--
B
--
C
--
D
--
E
-A
A
B
E
B
C
D
E
---
C
D
--
--
E
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Construction of the Charts
15
 In the prior example, all flows occurred in
lexicographic
order (A-B, A-D), so only the upper triangular portion of
the from-to chart had non-zero numbers
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Qualitative Flow Measurement
16
 Captured in what is called an Activity Relationship Chart
 The
criticality of department adjacency is captured on the
following scale:






A – Absolutely necessary
E – Especially important
I – Important
O – Ordinary closeness OK
U – Unimportant
X – Undesirable
 Assessed through interviews and meetings
 Can also construct activity relationship charts from flow
data by equating flow amounts to activity codes
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Example
17
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Determining Space Requirements
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 Often very political
 Not independent of scheduling/inventory control,
storage and delivery methods
 Can generate multiple alternatives if certain details are not
established
 Approaches – Departmental requirements
 Use historical data, data from other facilities
 Ground-Up approach
• Workstation requirements  Departmental requirements
• Apply a combination of checklists, reviews with personnel
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Determining Space Requirements
(cont.)
19
 Equipment considerations related to space






Equipment footprint
Machine travel
Room for materials in process (e.g., long bar stock)
Room for equipment maintenance
Room for plant services
…
 Where to get information




Equipment manufacturers
Current installation
Operator interviews
…
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Determining Space Requirements
(cont.)
20
 Materials related space






Receiving and storing (plant, department, WS)
Work-In-Process
Shipping, finished goods (plant, department, WS)
Storing/removal of waste
Tools, supplies, manuals, other equipment
…
 Aisle space
 See tables 3.3, 3.4 – General aisle space allowances based on flow
and size of loads moved
 See next slides
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Personnel Space at a Workstation
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 More detailed design/layout
 Addressed in ergonomics/human factors
 Guidelines and regulations exist
 U.S. Department of Labor Occupational Safety & Health
Administration
• www.osha.gov
• People available to help with compliance
 U.S. Department of Health and Human Services – Center for
Disease Control and Prevention: National Institute for
Occupational Safety and Health
• www.cdc.gov/niosh
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Generating Layout Alternatives
22
 Objective
 Develop a good or optimal block layout
 Block layout
 A two dimensional top down view arrangement of departments
in a facility
 Departments are represented as rectangles (or shapes
constructed from rectangles) with the relative area of the
department captured by the size of the rectangle
Office
Stores
Fab
Assembly
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
Paint
Maint
Sup
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Layout Levels
23
Level
Activity
Space
Planning Unit
Environment
I
Global
Site Location &
Selection
Sites
World or Country
II
Supra
Site Planning
Buildings or Site
Features
Site
III
Macro Layout
Building
Department or
Block Layout
Workcells or
Departments
Building
IV
Micro Layout
Workcell of
Department
Workstations or
Workcell
Features
Cells or
Departments
V
Sub Micro
Layout
Workstation
Design
Tool & Fixture
Locations
Workstation
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
From: http://www.strategosinc.com/facility_plan_levels.htm
Output
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Generating Layout Alternatives
24
 Procedures
 Construction procedures
• “Greenfield” layout, the layout of a new facility
 Improvement procedures
• Changes/ improvements to existing facilities
 Not a critical distinction
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Systematic Layout Planning (SLP)
25
 A qualitative method
1. Use a from-to or flow-between chart and/or an activity
relationship chart, and space requirements to create a
relationship diagram
2. Next, use the relationship diagram to create a space
relationship diagram
3. The space relationship diagram is used to generate layout
alternatives in the form of block layouts
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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SLP Example
26
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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SLP Example (cont.)
27
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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SLP Example (cont.)
28
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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SLP Example – Problem 6.7
29
 Four depts. are to be located on a 600’ x 1000’ bldg.
The expected personnel traffic flows and area
requirements for departments are shown in the tables
below
a. Develop a block layout design using SLP
Dept.
A
B
C
D
Dept.
Dimen.
A
0
250
25
240
A
200’x200’
B
125
0
400
335
B
400’x400’
C
100
0
0
225
C
600’x600’
D
200’x200’
D
125
285
175
0
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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SLP Example – Problem 6.7 (cont.)
30
1) Construct a Flow-Between Chart
A
A
B
B
C
D
---
C
D
---
2) Rank the department pairs in order of greatest two-way flow
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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SLP Example – Problem 6.7 (cont.)
31
3) Create an Activity-Relationship diagram
4) Create a Space-Relationship diagram
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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SLP – In Class Example
32
4) Generate layout options
1
2
3
4
5
6
7
8
9
10
1
2
3
4
5
6
7
8
9
10
1
2
3
4
Dept.
Dimen.
5
A
200’x200’
6
B
400’x400’
C
600’x600’
D
200’x200’
1
2
3
4
5
6
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
WINTER 2012
Computer-Aided Layout
33
 Computer-aided layout supports layout design
 Generate many layout alternatives in a short time
 Helps conduct what if and sensitivity analysis
 Modeling the problem helps understand the system
perspective
 Commercial software
 Most algorithms have not yet been commercialized although
they are available as research code and used by consultants
 Educational software is available
• We will use one package
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
WINTER 2012
Computer-Aided Layout (cont.)
34
 Inputs
1. From-To chart and/or
2. Activity relationship chart
 You may have the flexibility to map the A,E,I,O,U,X scale to
different numerical scales
 Can change results by changing the scaling
 Can have negative values for relationships (e.g., X)
3. Usually, the building footprint
 May be restricted to a rectangular footprint
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Computer-Aided Layout (cont.)
35
 Layout development criteria
 When constructing a layout, an algorithm implemented on a
computer needs specific criteria to compare alternative layouts
 These criteria may differ depending on the form of input data
characterizing flow/relationships
 The criteria must be computable (quantitative) and is referred
to as the objective function of the layout problem
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Computer-Aided Layout (cont.)
36
 From-to chart as input data
 The objective will be to construct a layout to minimize
required movement costs over a specific time period
Notation:
m  The number of departments in the layout.
fij  The department i to department j flow (from-to data).
cij  The cost of moving a load one distance unit from department
i to department j.
dij  The distance from department i to department j.
z  Total movement cost per time period (the objective function value).
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Computer-Aided Layout (cont.)
37
 The objective function can be expressed as:
m
m
z   f ij cij dij
i 1 j 1
 This is called a
distance-based objective function
 The fij and cij are input data
 If the cij= 1 for all i and j, z= total travel distance
per time period
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Distance Measure
38
 The dij’s are normally
rectilinear centroid to centroid
distance
 The dij’s change as a function of department location
and shape
 Rectilinear distance’s
If thecentroidof department1 is locatedat ( x1 , y1 )
and thecentroidof department2 is locatedat ( x2 , y2 )
thend12 | x1  x2 |  | y1  y2 |
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Centroids
39
 Centroid
 Center of gravity or mass
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Centroids (cont.)
40
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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In-class Exercise
41
 Find the centroid
y
40
35
30
25
20
15
10
5
0
0
10
20
30
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
40
50
x
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In-class Exercise
(cont.)
42
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Computer-Aided Layout
43
 Activity relationship chart as input
 The activity relationship between departments i and j must
first be quantified to get fij, which represents the
relationship strength on some numerical scale
 One possible objective function:
m
m
z   f ij xij
i 1 j 1
1 if depts.i and j are adjacent
where xij  
otherwise
0
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Computer-Aided Layout (cont.)
44
 This is called an
adjacency based objective
 Since the numerical scale is arbitrary, another
objective function is often used
 Called an efficiency rating (or normalized adjacency score)
 It is a relative measure of a layout with respect to the best
(sometimes not possible) objective function value
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Computer-Aided Layout (cont.)
45
m
 No negative fij values
z
m
 f
i 1 j 1
m m
 f
i 1 j 1

 Negative fij values
x
ij ij
z  i , jF
fij xij 

i , jF
ij

i , jF
fij 
f ij (1  xij )

i , jF
fij
F  The set of dept. pairs with fij  0
F  The set of dept. pairs with fij  0
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Computer-Aided Layout (cont.)
46
Facility Layout:
1
3
Adjacency:
2
Flows:
1
1
A
4
E
2
X
U
X
3
2
1
2
3
4
-
20
10
5
-
-10
-5
-
8
3
4
O
-
4
F
X12 =
X23 =
X13 =
X24 =
F
X34 =
X14 =
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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In-class Exercise
47
 Evaluate the efficiency rating and total travel
distance for the layout generated in the SLP example
Dept.
A
B
C
D
Dept.
Dimen.
A
0
250
25
240
A
200’x200’
B
125
0
400
335
B
400’x400’
C
100
0
0
225
C
600’x600’
D
200’x200’
D
125
285
175
0
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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In-class Exercise
(cont.)
48
A
A
B
C
D
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
B
C
D
-----
WINTER 2012
“Optimizing” a Layout
49
 Finding the optimal layout that minimizes either of
the objective functions described is a very difficult
problem (computationally)
 General methods for exploring the space of layouts
have been applied
 Pairwise exchange method
• A general approach used to improve an existing layout
 Graph-based method
 Other methods
• Metaheuristics
• Covered in IE 425
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Pairwise Exchange Method
50
 This is a heuristic search procedure
 Not guaranteed to find the optimal layout (except under
certain circumstances)
 In general, this is a method that should be
computerized but is applicable by hand in small
examples
 We will examine an example with the cost of
material movement used as a criteria to evaluate
layouts (distance based objective)
 If all costs are the same (=1), this is total distance
 Activity relationship charts and adjacency based objectives can
be used
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Pairwise Exchange Method (cont.)
51
 Algorithm
1. “Layout” = Initial layout. “Cost” = Distance based cost for
“Layout”
2. For each possible pairwise exchange of departments in
“Layout”, calculate the total distance based cost
3. If the lowest cost from the pairwise exchanges is > “Cost”,
go to 4
 Else “Layout” = Layout with the lowest cost
“Cost” = Lowest cost from step 2
 Go to 2
4. End with “Layout” and “Cost” as the final layout and cost
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Pairwise Exchange Method (cont.)
52
 Example from text
 Assume distances are centroid to centroid
 Assume travel from dept i to j is symmetric
Flow-between chart
Dept.
1
2
3
4
1
-
Department
2
3
10
15
10
-
4
20
5
5
-
Distances
Dept.
1
2
3
4
1
-
Department
2
3
1
2
1
-
4
3
2
1
-
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Pairwise Exchange Method (cont.)
53
(a) Iteration 0
1
2
3
4
TC2134(1-2) = 10(1) + 15(1) + 20(2) + 10(2) + 5(3) + 5(1) = 105
TC3214(1-3) = 10(1) + 15(2) + 20(1) + 10(1) + 5(2) + 5(3) = 95
TC4231(1-4) = 10(2) + 15(1) + 20(3) + 10(1) + 5(1) + 5(2) = 120
TC1324(2-3) = 10(2) + 15(1) + 20(3) + 10(1) + 5(1) + 5(2) = 120
TC1432(2-4) = 10(3) + 15(2) + 20(1) + 10(1) + 5(2) + 5(1) = 105
TC1243(3-4) = 10(1) + 15(3) + 20(2) + 10(2) + 5(1) + 5(1) = 125
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Pairwise Exchange Method (cont.)
54
(b) Iteration 1
3
2
1
4
TC3124(1-2) = 10(1) + 15(1) + 20(2) + 10(2) + 5(1) + 5(3) = 105
TC1234(1-3) = 10(1) + 15(2) + 20(3) + 10(1) + 5(2) + 5(1) = 125
TC3241(1-4) = 10(2) + 15(3) + 20(1) + 10(1) + 5(1) + 5(2) = 110
TC2314(2-3) = 10(2) + 15(1) + 20(1) + 10(1) + 5(3) + 5(2) = 90
TC3412(2-4) = 10(1) + 15(2) + 20(1) + 10(3) + 5(2) + 5(1) = 105
TC4213(3-4) = 10(1) + 15(1) + 20(2) + 10(2) + 5(1) + 5(3) = 105
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Pairwise Exchange Method (cont.)
55
(b) Iteration 2
2
3
1
4
TC1324(1-2) = 10(2) + 15(1) + 20(3) + 10(1) + 5(1) + 5(2) = 120
TC2134(1-3) = 10(1) + 15(1) + 20(2) + 10(2) + 5(3) + 5(1) = 105
TC2341(1-4) = 10(3) + 15(2) + 20(1) + 10(1) + 5(2) + 5(1) = 105
TC3214(2-3) = 10(1) + 15(2) + 20(1) + 10(1) + 5(2) + 5(3) = 95
TC4312(2-4) = 10(1) + 15(1) + 20(2) + 10(2) + 5(3) + 5(1) = 105
TC2413(3-4) = 10(2) + 15(1) + 20(1) + 10(3) + 5(1) + 5(2) = 100
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
WINTER 2012
Graph-based Method
56
 Often applied when using an adjacency-based
objective
 A method that uses a graph (nodes connected by
arcs) to represent departments and their adjacencies
to other departments
 Departments = nodes
 If an arc connects two departments, they are adjacent
• Arcs have values that represent adjacency relationships
 Finding the best layout amounts to finding the best graph
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Graph-based Method (cont.)
57
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Graph-based Method (cont.)
58
 Procedure for generating an adjacency graph
1. Find the highest valued adjacency relationship as the starting
nodes connected by an arc (break ties randomly)
2. The third department selected will have the largest total
relationship value with the two departments selected in step
1
3. The next departments to enter are selected one at a time
based on the highest total relationship values added when
the department is placed on the “face” of the existing graph
 A face is a region bounded by arcs of the graph
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Graph-based Method (cont.)
59
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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Graph-based Method (2)
60
 A department block layout still needs to be
constructed from the graph in a manner similar to
SLP
IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT
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