A Framework for Stepwise Life Cycle Assessmentduring Product Design with Case-Based Reasoning

Myeon-Gyu Jeong, Hyo-Won Suh, James R. MorrisonDepartment of Industrial and Systems Engineering

KAIST(Korea Advanced Institute of Science and Technology)

2010. 8. 22

0. Contents

1. Research Background1. Research motivation and necessity2. Related work3. Research purpose and scope

2. Research Method1. Research framework2. Framework of CBR (Case-Based Reasoning) for LCA3. Environmental Character Evaluation Matrix (ECEM)4. Selective LCA using the result of CBR

3. Case study1. Case product and LCA result2. The LCA results and case representation3. Stage 1: ECEM and use of CBR for whole product4. Stage 2: Use of CBR for part or module5. Stage 3: Selective LCA using the result of ECEM and CBR

4. Concluding remarks

2

1. Research Background1. Research Motivation and Necessity2. Related Work3. Research Purpose and Scope

3

1.1 Motivation and Necessity

Numerous environmental Conventions (UNFCCC, Kyoto Protocol) Regulations (Reach, RoHS, EuP, WEEE, ELV) and Policies (IPP, SCEM, Environmental labaling, EPR)

Drive companies to consider eco-factors

To address environmental concerns, companies may Use an eco-design methodology for their products Develop a system to check regulation satisfaction Use environmental effect assessment methodology: LCA

● UNFCCC = United Nations Framework Convention on Climate Change● Reach, RoHS, EuP, WEEE, ELV● Eco-product related Policy - IPP, SCEM, Environmental Labeling, EPR

4

1.1 Motivation and Necessity

Streamlined LCA

is a technique that purposely adopts a [simplified approach] to life cycle assessment

Life Cycle Assessment

is an analytical methodologyto identify and assess the environmental aspects and potential impacts associated with a product throughout its life cycle

Not applicable to early product development stage Time consuming, data-intensive and sometimes difficult to communicate with non-envi-

ronmental experts Data collection and analysis challenges limit the accuracy and completeness of LCA

Limitations of LCA

5

1.2 Some Previous Efforts to Streamline LCA

Material(Acquisition)

Manufacture

Use

Disposal

Material, Energy

Air, Water, Waste

Material, Energy

Air, Water, Waste

Material, Energy

Air, Water, Waste

Material, Energy

Air, Water, Waste

Environmental Impact Assessment

BLACK BOX(ANN, Regression, etc.)

Results

Product Attribute+

Existing Full LCA resultsEnvironmental category

Life

cy-cle stage

Scoringbased on checklist

Product Attributes

Matrix Operation(Weighting, Sum.)

Results

2. Simplified LCA 3. Numerical Method1. Matrix Method

Compare results

Lear

ning

/Fi

tting

Output

(Omit indifferent process or in/output)

Ines Sousa(2000), Seo, K.K(2006)Graedel & Allenby(1995), Pommer(2001) Christiansen, K.(1997), Hur, T.(2003)

No systematic procedure to select life-stageand part/module of product

Hard to learning or fitting the black box and applicable to only specific product category& environmental stressor

Only qualitative assessment andlow accuracy of result

Suggested by

Limitations

Input

6

1.3 Research Purpose and Scope

CBR Framework for LCA• Replace complicated evaluation process with CBR• Quantitative LCA in early design stage• Using known LCA results, predict LCA results for

new product/part

FBSe expression• Function-Behavior-Structure-environmental effect• Case expression method• Support efficient use of existing LCA result cases

ECEM• Environmental Character Evaluation Matrix• Support systematic selective LCA process

Selective LCA• Selective LCA using the result of ECEM and CBR• Part selection method using CBR results

Concept design System level design Detail design

LCA with CBR/ECEM LCA with CBR Selective LCA

support

Step-wiseLCA

utilize

utilize

7

2. Research Method1. Research Framework2. Framework for CBR3. Environmental Character Evaluation Ma-

trix(ECEM)4. Selective LCA using the result of ECEM

and CBR

8

2.1 Research Framework

1. Product-level evaluation using CBR

4. Select important part/module(Relative Importance)

3. Functional module evaluation using CBR

CBR

2. ECEM

Stage 1 Stage 2

Concept Design System-Level Design

Stage 3

Detail Design

Selective LCA

Quantitative LCA

Design output → Attribute Design output → Attribute

BOM(1

)BOM(2

)

Feed

back

toco

ncep

t des

ign

Feedback tosystem

-level designSupport Selective LCA

Quantitative LCA in early design stage Improved Selective LCA

with ECEM & CBR

Support eco-design with LCA result

9

2.2 Framework of CBR for LCA

Product AF B S e

Module 1F B S e

Module 2F B S e

Sub-Module 2

F B S e

Sub-Module 1

F B S e

Sub-Module 3

F B S e

Case memory

…

…

…

New Solution(LCA)

Design output → Attribute

Index

Retrieve

Select

Recall

Modify

Evaluate

Adapt

Update new case

Product Level

Module Level

Sub-ModuleLevel

Stage 1

Stage 2

Function: The purpose of the design (product) (e.g. cellular phone must communicate information to user;)

Behavior: Required functional module/parts and manufacturing process (e.g. visual information display by LCD panel)

Structure: Description of the physical characteristics of the object (e.g. geometry size, material, color)

Environmental Effect: Description of the environmental effect of a product (e.g. global warming, ozone layer depletion, acidification)

FBSe expression for case representation:

Cases are divided into three levels by product structure.Each attribute has four FBSe elements

Case memory organization and reasoning process:

10

2.2 Framework of CBR for LCA

Function

Behavior

Structure

Environmental effect

Function Attribute 1(Value)

Function Attribute 2(Value)

Function Attribute n(Value)

Behavior Attribute 1(Value)

Behavior Attribute 2(Value)

Structure Attribute 1(Value)

Structure Attribute 2(Value)

Behavior Attribute n(Value)

Structure Attribute n(Value)

Case R

etrieval Area

(Used to m

atch cases)

Global warming(Value)

Acidification(Value)

Eutrophication(Value)

PhotochemicalOxidant Creation

(Value)

……

……

……

Prob

lem

spa

ce(C

BR

Inpu

t)So

lutio

n sp

ace

(CB

R O

utpu

t)C

ase Adaptation A

rea(U

sed to modify result)

……

General form of LCA results when FBSe expression is used:

By FBSe Expression, LCA result of similar module/part in different product could be retrieved and utilized

11

2.2 Framework of CBR for LCA

Product AF B S e

Module 1F B S e

Module 2F B S e

Sub-Module 2

F B S e

Sub-Module 1

F B S e

Sub-Module 3

F B S e

Case memory

…

…

…

New Solution(LCA)

Design output → Attribute

Index

Retrieve

Select

Recall

Modify

Evaluate

Adapt

Update new case

Product Level

Module Level

Sub-ModuleLevel

Stage 1

Stage 2

Weight of attribute i: wi (Nonnegative real number [1,5])Degree of similarity between cases x and y: sim(x,y) (Real number in [0,1])Values for attribute fi: fi N, fi

A (N is new design, A is case A)

𝑆𝑖𝑚𝑖𝑙𝑎𝑟𝑖𝑡𝑦 ሺ𝑁𝑒𝑤 𝐷𝑒𝑠𝑖𝑔𝑛,𝐶𝑎𝑠𝑒 𝐴ሻ= 1σ 𝑤𝑖𝑛𝑖=1 ሼ𝑤𝑖 × 𝑠𝑖𝑚ሺ𝑓𝑖𝑁,𝑓𝑖𝐴ሻሽ𝑛

𝑖=1

Similarity computation: Clos

est c

ase

is se

lect

edby

sim

ilarit

y co

mpu

tatio

n

12

2.2 Framework of CBR for LCA

Product AF B S e

Module 1F B S e

Module 2F B S e

Sub-Module 2

F B S e

Sub-Module 1

F B S e

Sub-Module 3

F B S e

Case memory

…

…

…

New Solution(LCA)

Design output → Attribute

Index

Retrieve

Select

Recall

Modify

Evaluate

Adapt

Update new case

Product Level

Module Level

Sub-ModuleLevel

Stage 1

Stage 2

IF Material category of object = Material category of

case

THEN Select case

ELSE Search other cases

(1) Checking procedure of material coincidence (2) Mass compensation

The LCA results can be affected by several factors, but highly depend on material and mass.

Therefore, it is necessary to check the coincidence of material and compensate the mass difference.

Case Adaptation:

13

2.3 Environmental Character Evaluation Matrix

Life Stage

Environmental Stressor 　Global warming Ozone Layer

Depletion Acidification … Average

Pre-manufacture Value (1~5) … Value (1~5) … Val. Sum

Part/Material … Part/Material … Part/Material

Product manufacture … Value (1~5) … … Val. Sum

… Part/Material … … Part/Material

Disposal… … … … Val. Sum

… … … … Part/Material

...… … … … …

… … … …… …

AverageVal. Sum Val. Sum Val. Sum … 　

Part/Material Part/Material Part/Material …

Input the life-stages

Important environmental stressor and related part/material information

Important life-stage and related part/material information

Purpose: to search product characterized attributes which could not be found in CBR system, and feedback the results to later design process and selective LCA

Input the value1(weak effect) ~ 5(serious effect)and related part/material

Input the environmental stressor

Searching for product attributes not found in the CBR system and for giving feedback to later design processes and selective LCA processes via E-BOM

14

2.3 Selective LCA using the result of CBR

Existing LCA method evaluate the contribution by only quantity of matter, then exclude the part which have the value below a threshold

Proposed method select important part/module based on critical value and relative importance from CBR results

Even though some part has little mass,it can have large environmental effect owing to their manufacturing process, etc.

BEGIN

IF Relative importance of part/module < Critical

value

THEN Remove the part/module from selective LCA

list

END

2. Important part selection procedure1. Relative importance

Relative importance = Total effect of moduleTotal effect of product

Use of CBR results in the selection of important parts:

15

3. Case study – Mobile Phone1. Case product and LCA results2. The LCA results and case representation3. Stage 1: ECEM and use of CBR for whole prod-

uct4. Stage 2: Use of CBR for part or module5. Stage 3: Selective LCA using the result of ECEM

and CBR

16

GW AD EU POC ARD0.00E+00

1.00E-04

2.00E-04

3.00E-04

4.00E-04

5.00E-04

6.00E-04

Nor

mal

ized

Env

ironm

enta

l Eff

ect

(pe.

yr/fu

)

3.1 Case product and LCA results

*ReferenceLCA Procedure : ISO 14040 series practical guideline, 2004. Life cycle inventory DB : KNCPC (Korea national Cleaner Production Center in KITECH

Legend:

GW : Global warming AD : Acidification

EU : Eutrophication POC : Photochemical oxidant creation

ARD : Aboic resource depletion

The LCA results for mobile phone

Back Panel

Battery PackBattery Housing

Inner Panel

Key Pad

Number Pad

LCDPCB 1 PCB 2

PCB 2Plate

Slide LWR Slide UPRSlide UPR Panel

Bolts & PlasticsFRT Panel

Mobile phone and specification

17

3.2 Case representation of LCA results

Function

Behavior

Structure

Environmental effect

Phone call(Mobile phone call)

Camera(Take picture/movie)

Entertainment(Play music/movie clip)

Voice call(Speaker, Microphone)

Camera(Type:1.3M pixel CMOS)

Display module(Type: TFT LCD)

Battery(Type: Li-ion polymer)

Material(Polypropylene)

Color(Black)

Height(16.9mm)

Length(93mm)

Width(46mm)

Mass(94.9g)

Memory(Type: Flash)

Battery spec.(3.7Voltage, 800mAh) Memory capacity

(58.5 Mb)Display size

(2.0 inch)

Global warming(5.04E-04 pe•yr/fu)

Acidification(1.97E-04 pe•yr/fu)

Eutrophication(1.02E-05 pe•yr/fu)

PhotochemicalOxidant Creation

(3.69E-05 pe•yr/fu)

Azoic ResourceDepletion

(3.27E-04 pe•yr/fu)

FBSe expression of the mobile phone LCA results

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Life stageEnvironmental Stressor 　

GW AD EU … ARD Average

Pre-manufacture5 5 3

…

5 4.4

Battery pack Housing/PC - PCB Housing, LCD,PCB, Battery Pack

Product Manufacture5 3 2 3 2.8- - Housing/PC - Housing/PC

Product Delivery1 1 0 2 0.8- - 　 - 　

…Refurbishment,

Recycling, Disposal1 1 3 2 1.6- - Battery Pack - Battery Pack

Average3 2.4 1.6 … 2.4 　　 Housing/PC Housing/PC,

Battery Pack … PCB,Battery Pack

3.3 Stage 1:ECEM and use of CBR for whole product

No Level Part Name Material Environmental Effect (pe.yr/fu)1 2 3 4 5 GW AD EU … ARD

1 ○　　　　 Cellular Phone - 5.04E-04 1.97E-04 1.02E-05 3.27E-042 　 ○　　　 FRT CASE ASSY - 　 　 　

…

　3 　　 ○ 　　 FRT Pannel PC 　 ⑤ ② 　4 　　 ○ 　　 Slide UPR PC 　 ⑤ ② 　

12　　　 ○　 PCB 1 FR4 　 　 　 ⑤21　　　 ○　 Battery ASSY - 　 　 　 　22　　　　 ○ Battery Housing PC 　 ⑤ ② 　24　　　　 ○ Battery Pack NMP, LiCoO2, AL… ⑤　 　 ③ ②

ECEM (Environmental Character Evaluation Matrix):

Pre-manufacture

Productmanufacture

ProductDelivery

ProductUse

Refurbishment,Recycling,Disposal

0

2

4

GW

AD

EUPOC

ARD

0

2

4

Life stage

Environmental Stressor

Spiderweb chart helps us easily explore the important life stage,the related parts or modules, and the environmental stressor

We can estimate LCA result of whole product by using CBR, and this can be summarized in BOM with ECEM result.

Designers can modify the product based on this BOM to be more eco-friendly.

Environmental BOM(1): Based on ECEM results

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3.4 Stage 2: Use of CBR for part or module

Value Attribute Case 1

Show image/movie Display Function

Qualcomm 233Mhz Graphic processor

BehaviorTFT LCD Display module

3.7V Li-ion battery Power source

New problem Attribute (Weight) Value

Function Display(5) Show image/movie

Behavior

Graphic processor (1) Qualcomm 600Mhz

Display module (4) TFT LCD

Display color (2) 262,000

1.0

0.8

1.0

0

Value Attribute Case 2

Show image/movie Display Function

ARM11 S3C6410 Graphic processor

BehaviorAM OLED Display module

3.7V Li-ion battery Power source

1.00.3

0.1

0

New problem Attribute (Weight) Value

Function Display (5) Show image/movie

Behavior

Graphic processor (1) Qualcomm 600Mhz

Display module (4) TFT LCD

Display color (2) 262,000

sim

sim

𝑆𝑖𝑚𝑖𝑙𝑎𝑟𝑖𝑡𝑦 ሺ𝑁𝑒𝑤,𝐶𝑎𝑠𝑒 1ሻ= 1൫5+1+4+2൯൛൫5× 1.0൯+ሺ1× 0.8ሻ+ሺ4× 1.0ሻ+ሺ2× 0ሻൟ= 0.49

𝑆𝑖𝑚𝑖𝑙𝑎𝑟𝑖𝑡𝑦 ሺ𝑁𝑒𝑤,𝐶𝑎𝑠𝑒 2ሻ= 1ሺ5+ 1+ 4+ 2ሻሼሺ5 × 1.0ሻ+ሺ1× 0.3ሻ+ሺ4 × 0.1ሻ+ (2× 0)ሽ= 0.285

Similarity computation of two different LCD modules

Case 1 is more similar to the New problem due to “Display module”The LCA results of whole product in Stage 1 and other parts or modules can be estimated with same procedure

20

3.5 Stage 3: Selective LCA using the result of ECEM and CBR

8

4

3

5

9

11

Part selection method based on CBR results is more simple and precise

Critical value = 0.02(less than 2%)

1 2 3 4 5 GW AD EU POC ARD1 ○ Cellular Phone - 5.04E-04 1.97E-04 1.02E-05 3.69E-05 3.27E-042 ○ FRT CASE ASSY -3 ○ FRT Pannel PC 9 2.86E-06 2.87E-06 1.31E-06 5.22E-06 1.43E-05 0.0864 O4 ○ Slide UPR PC 8 2.54E-06 2.55E-06 1.17E-06 4.64E-06 1.27E-05 0.0768 O5 ○ Slide UPR Pannel STEEL 6 3.87E-06 0.00E+00 0.00E+00 0.00E+00 4.96E-06 0.0142 X6 ○ Screws STEEL 1.5 9.67E-07 0.00E+00 0.00E+00 0.00E+00 3.04E-06 0.0058 X7 ○ Key PAD ASSY -8 ○ Key PAD RUBBER 0.5 1.59E-08 2.33E-08 1.94E-08 2.09E-08 3.63E-08 0.0006 X9 ○ Key PAD Ring AL 0.5 1.62E-07 1.17E-07 6.89E-08 5.15E-08 3.09E-07 0.0025 X11 ○ LCD Glass, Styrofoam…10 9.54E-06 6.49E-06 3.51E-06 9.04E-06 3.66E-05 0.1976 O

RelativeImportance

SelectPartNo Level Part Name Material Mass

(g)Environmental Effect (pe.yr/fu)

BOM(2

)

CBR result of case 1 can be adapted to new product design

21

Life stages

Considering parts

Environmental stressor

CBR

ECEM

ECEM

Selective LCA

4. Concluding Remarks

(1) CBR framework for LCA : Quantitative LCA in early design stage, Fast and effec-tive LCA by replacing complicated evaluation process with CBR

(2) FBSe expression method for CBR: Support efficient use of existing LCA cases by expressing product, module, part-level with FBSe

(3) ECEM to support CBR: Fills in gaps in eco-analysis that CBR cannot well answer

(4) Selective LCA : Part selection method using CBR results

(5) Integration of stepwise LCA procedure with environmentally extended BOM : Support gradual eco-improvement of product in each design stages

22

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