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Inventory Guru Introduction
© 2013 LLamasoft, Inc. All Rights Reserved
Introducing the New Inventory Guru
ADAPTIVE INTELLIGENT INVENTORY OPTIMIZATION (AI+IO)
INVENTORY GURU
DEMAND ANALYSIS
DEMAND CLASSIFICATION
MULTI-ECHELON INVENTORY OPTIMIZER
DISCRETE EVENT INVENTORY SIMULATION
NETWORK OPTIMIZATION
© 2013 LLamasoft, Inc. All Rights Reserved
What is new in AI+IO?
Demand analysis and advance demand statistics• Mean and std. dev. of nonzero demand and inter-demand interval
mean• Propagation of these advance demand statistics
Demand classification• Automatically analyze and classify up to 10 different types of non-
normally distributed demand• Demand classification for each facility in a given network
Inventory policy recommendations• Summary and detailed inventory outputs
3 different definitions of service level• Type 1 (cycle service level)• Type 2 (fill rate): Improved formulation• Type 3 (ready rate)
© 2013 LLamasoft, Inc. All Rights Reserved
What is new in AI+IO?
Better inventory modeling with various distributions• Normal, Poisson, Negative Binomial, Gamma, and Mixture Distributions• Use of historical demand or forecast data to determine a right
distribution based on characteristics
Dynamic programming approach for the solution of Guaranteed Service Time Algorithm• Dramatic improvements in run time.• Ability to handle complicated network/BOM structures.• Provide a framework for adding new constraints /features.
Set service time for different destinations. Takes into account more than one inbound transportation modes.
© 2013 LLamasoft, Inc. All Rights Reserved
What’s Different in Inputs?
Products: None Sites: None Demand: None Sourcing Policies
• MOQ is required since it’s used to calculate both the Q and demand variability
Transportation Policies • Minimum Shipment Quantity— similar to MOQ but considers Mode• Minimum/Maximum Service – similar to service time in IP but considers Mode
Inventory Policies• Safety Stock Rule has been removed since it is now obsolete
Multi-Period Inventory Policies• Service Requirement is now supported
User Defined Customer/Facility Demand Profile• Inputs added for Non-Zero Demand Mean, Non-Zero Demand Std Dev and Inter-
Demand Interval Mean
© 2013 LLamasoft, Inc. All Rights Reserved
What’s Different in Outputs
Safety Stock Details • Now replaced by Inventory Policy Details and Inventory Policy
Summary• Added recommended control policies• Added additional statistics• Added additional approximated operating parameters
Customer/Facility Daily Demand• Replaced by Aggregated Customer Demand and Aggregated
Customer Facing Facility Demand
Customer/Facility Demand Profile• Added demand classification columns and additional statistics
Inventory Specific Tableau Outputs
© 2013 LLamasoft, Inc. All Rights Reserved
What’s Different In Settings
Full Scenario Support Control over thresholds Control over outlier handling Single/Multi-Echelon setting is now at
global level
© 2013 LLamasoft, Inc. All Rights Reserved
What happens when I upgrade?
All input tables except for User Defined are intact
Both User Defined tables are cleared SSO outputs from IO2 are cleared Demand profiles and daily demand details
are preserved As usual, a backup of the IO2 model will be
made automatically
© 2013 LLamasoft, Inc. All Rights Reserved
New Demand Propagation
© 2013 LLamasoft, Inc. All Rights Reserved
What is demand propagation?
Warehouse
Facility1
Facility2
Customer1
Customer2
Demand Series1
Demand Series2
Propagated Demand
External Supplier
© 2013 LLamasoft, Inc. All Rights Reserved
How does demand propagation work?
Warehouse
Facility1
Facility2
Customer1
Customer2
𝝁 ,𝝈𝝁𝑵𝒁 ,𝝈𝑵𝒁 ,𝒑
Demand Series1
Demand Series2
Demand MeanDemand StdDevNZ Demand MeanNZ Demand StdDevDemand Interval Mean
𝝁 ,𝝈𝝁𝑵𝒁 ,𝝈𝑵𝒁 ,𝒑
𝝁 ,𝝈𝝁𝑵𝒁 ,𝝈𝑵𝒁 ,𝒑
External Supplier
© 2013 LLamasoft, Inc. All Rights Reserved
Example: Demand Propagation
12
1
3
2
7
6
5
4 Customer demand(𝑇 4 ,𝑀 4 )
(𝑇 5 ,𝑀5 )
(𝑇 6 ,𝑀 6 )
(𝑇 7 ,𝑀7 )
(𝑇 2 ,𝑀2 )
(𝑇 3 ,𝑀 3 )
ExternalSupplier
StockpointDemand Demand StatisticsReplenishment Order Statistics (𝑇 𝑖 ,𝑀𝑖 )
Demand Propagation
Demand Propagation
(𝜇 ,𝜎 ,𝝁𝑵𝒁 ,𝝈𝑵𝒁 , 𝒑 )
,
(𝜇 ,𝜎 ,𝝁𝑵𝒁 ,𝝈𝑵𝒁 , 𝒑 )
(𝜇 ,𝜎 ,𝝁𝑵𝒁 ,𝝈𝑵𝒁 , 𝒑 )
(𝜇 ,𝜎 ,𝝁𝑵𝒁 ,𝝈𝑵𝒁 , 𝒑 )
(𝜇 ,𝜎 ,𝝁𝑵𝒁 ,𝝈𝑵𝒁 , 𝒑 )
(𝜇 ,𝜎 ,𝝁𝑵𝒁 ,𝝈𝑵𝒁 , 𝒑 )
(𝜇 ,𝜎 ,𝝁𝑵𝒁 ,𝝈𝑵𝒁 , 𝒑 )
Customer demand
Customer demand
Customer demand
© 2013 LLamasoft, Inc. All Rights Reserved
Why we need advance demand statistics?
To take into account batching effect• Batch size (Q) might have a great impact on the variability for
the upstream echelon
To perform demand classification• , are used for algorithm
© 2013 LLamasoft, Inc. All Rights Reserved
Example-1: Impact of Batching on Demand Propagation
© 2013 LLamasoft, Inc. All Rights Reserved
Demand Process in CentralWarehouses
Product Facility Intermittency VariabilityDemand
ClassClumpiness
Demand Mean
Demand StdDev
Demand Size Mean
Demand Size StdDev
Demand Interval Mean
Product1 CentralWarehouse Intermittent HighlyVariable Slow - 49.70 70.66 100.23 4.83 2.02
Demand Process in CentralWarehouses
Product Facility Intermittency VariabilityDemand
ClassClumpiness
Demand Mean
Demand StdDev
Demand Size Mean
Demand Size StdDev
Demand Interval Mean
Product1 CentralWarehouse Intermittent HighlyVariable Slow - 49.30 70.22 100.00 4.34 2.03
IO2 Solution: Demand Propagation with Batch Size (Q) = 100
AI+IO Solution: Demand Propagation with Batch Size (Q) = 100
Simulation Verification
Demand Propagation: IO2 vs. AI-IO
Demand Process in CentralWarehousesProduct Facility
Demand Mean
Demand StdDev
Product1 CentralWarehouse 49.70 33.76
© 2013 LLamasoft, Inc. All Rights Reserved
Demand Classification
16
LumpySlowIntermittent
ErraticSmooth
Non-Intermittent
Demand
Cut-off value
Cut-off value
© 2013 LLamasoft, Inc. All Rights Reserved 17
Demand Classification
ErraticRegular Smooth(fast)
LumpySlow
=4
Demand size variability
Intermittent
Non-Intermittent
Low
High
=1.32
Squared coefficient of variation
=4
Low Variable
Hig
hly
Varia
ble
Low
Var
iabl
e
Hig
hly
Varia
ble
Low High
Low HighDemand size variability
Low High
Clum
ped
Slow
0 𝜎𝑁𝑍 ≅ 0
𝐶𝑉 𝑁𝑍2 =0.49
Regu
lar
Slow
𝐶𝑉 𝑁𝑍2 =
𝜎𝑁𝑍2
𝜇𝑁𝑍2
© 2013 LLamasoft, Inc. All Rights Reserved
Use of Demand Classification for
Safety Stock Placement
© 2013 LLamasoft, Inc. All Rights Reserved
Lead Time Demand Modeling
Why is the demand class important?Based on the demand class, we identify a distribution to model lead time demand (a LTD Distribution). This LTD Distribution is then used in the multi-echelon SS optimization to more accurately represent the lead time demand - compared to the typical assumption that lead time demand follows a normal distribution
20
Demand Class LTD DistributionSmooth NormalErratic Mixture of DistributionsSlow-LowVariable Poisson/Mixture of DistributionsSlow-HighlyVariable Poisson/Mixture of DistributionsLumpy Negative Binomial
© 2013 LLamasoft, Inc. All Rights Reserved
Control Policy Mapping Based on the demand class, we recommend an inventory
control policy
21
Demand Class Inventory Policy
Smooth (Normal) (r,Q)Erratic (s,S)
Slow-Low Variable Base-Stock
Slow-Highly Variable (s,S)
Lumpy (T,S)
AI+IO reports optimal policy parameters.
© 2013 LLamasoft, Inc. All Rights Reserved
How Does AI+IO Compare?
© 2013 LLamasoft, Inc. All Rights Reserved
Lumpy Demand Data
Intermittency Variability Demand Class Mean Variance Demand
Size MeanDemand Size
VarianceInter-Demand Interval Mean
Intermittent Highly Variable Lumpy 22.84 5492.31 56.06 11632.64 2.46
1 46 91 136 181 226 271 316 361 406 451 496 541 586 631 676 721 766 811 856 901 946 991 10360
100200300400500600700800900
1000
Three-Year Demand Series
Day
Dem
and
Size
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 490
100200300400500600700800900
1000
Fifty-Day Demand Series
Day
Dem
and
Size
© 2013 LLamasoft, Inc. All Rights Reserved
Observed Density AI-IO Assigned Density* Normal Assigned Density
L =
3
L =
5
0 200 400 600 800 1000
0.0
00
0.0
05
0.0
10
0.0
15
Density estimate of data
N = 640 Bandwidth = 12.77
De
nsi
ty
0 200 400 600 800 1000
0.0
00
0.0
02
0.0
04
0.0
06
Density estimate of data
N = 639 Bandwidth = 24.91
De
nsi
ty
-400 -200 0 200 400
0.0
00
00
.00
05
0.0
01
00
.00
15
0.0
02
00
.00
25
0.0
03
0
x
y
-400 -200 0 200 400 6000
.00
00
0.0
00
50
.00
10
0.0
01
50
.00
20
0.0
02
5
x
y
0 100 200 300 400 500 600
0.0
00
.02
0.0
40
.06
x
dn
bin
om
(x, siz
e =
0.4
77
32
46
19
, p
rob
= 0
.00
41
62
36
1)
0 100 200 300 400
0.0
00
.05
0.1
00
.15
0.2
0
x
dn
bin
om
(x, siz
e =
0.2
86
39
47
71
, p
rob
= 0
.00
41
62
36
1)
* Negative Binomial Distribution
Lead Time Demand Densities for Different Lead Times
© 2013 LLamasoft, Inc. All Rights Reserved
L =
10
L =
20
0 500 1000
0.0
00
00
.00
05
0.0
01
00
.00
15
0.0
02
00
.00
25
0.0
03
0
Density estimate of data
N = 630 Bandwidth = 49.78
De
nsi
ty
0 500 1000 1500 2000
0.0
00
00
.00
05
0.0
01
00
.00
15
Density estimate of data
N = 630 Bandwidth = 71.52
De
nsi
ty
-500 0 500 1000
0.0
00
00
.00
05
0.0
01
00
.00
15
x
y
0 500 1000 1500 2000
0.00
000.
0005
0.00
100.
0015
x
dnbi
nom
(x, s
ize
= 1.
9092
9847
6, p
rob
= 0.
0041
6236
1)
-500 0 500 1000 1500 2000
0.0
00
00
.00
02
0.0
00
40
.00
06
0.0
00
80
.00
10
0.0
01
2
x
y
0 200 400 600 800 1000
0.0
00
0.0
01
0.0
02
0.0
03
0.0
04
0.0
05
x
dn
bin
om
(x, s
ize
= 0
.95
46
49
23
8, p
rob
= 0
.00
41
62
36
1)
Lead Time Demand Densities for Different Lead Times (Cont’d)
Observed Density AI-IO Assigned Density* Normal Assigned Density
© 2012 LLamasoft, Inc. All Rights Reserved
IO3: Negative Binomial DistributionLe
ad T
ime
= 3
Safety Stock Results for 95% FillrateLe
ad T
ime
= 5
Metric Approximation Simulation
Type2 95% 94%
Safety Stock 537
Metric Approximation Simulation
Type2 95% 98%
Safety Stock 683
Metric Approximation Simulation
Type2 95% 95%
Safety Stock 590
Metric Approximation Simulation
Type2 95% 99%
Safety Stock 788
Optimal safety stock = 581
Normal Distribution
Optimal safety stock = 563
AI+IO IO2 / Current Gen Tools
© 2012 LLamasoft, Inc. All Rights Reserved
Safety Stock Results for 95% Fillrate
Lead
Tim
e =
10
Lead
Tim
e =
20
Metric Approximation Simulation
Type2 95% 95%
Safety Stock 698
Metric Approximation Simulation
Type2 95% 99%
Safety Stock 984
Metric Approximation Simulation
Type2 95% 96%
Safety Stock 862
Metric Approximation Simulation
Type2 95% 100%
Safety Stock 1257
Optimal safety stock = 699
Optimal safety stock = 834
Normal Distribution
AI+IO IO2 / Current Gen Tools