qualitative process analysis

Session 10 - Process Analysis (Process Maps, Cause-Effect, P-Diagram)

University of Michigan: Six Sigma Black Belt, P Hammett 1

Qualitative Process Analysis

Process Maps/Value Stream Map,

Cause-Effect Diagram and P-Diagram

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Case Study – Topic Motivation

Background: Sales Order Fulfillment Process (in-stock orders) Receive orders from mail, internet, phone, or fax

Reconcile orders (including credit check for new customers)

Assign orders to distribution center where they are picked, packed, and shipped

Goal is to fill orders in 3-5 business days

Current State: Takes 7-14 days (1st Pass Yield on Correct Order Shipment is ~92%)

Why does it take so long? What are sources of waste, improvement opportunities?

To address the problem, we need to Map the Process (understand the ‘as-is’ process with details about various process steps)



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Topics

I. Qualitative Process Analysis

II. Process Maps (Define/Measure)

A. SIPOC Diagram

B. Swim lane Process Map

C. Value Stream Map

D. Flow Chart/Process Mapping Diagram

Note: Above maps should be updated over a project

III.Brainstorming Variation Causes (Measure/Analyze)

E. Cause-and-Effect (Fishbone) Diagram

F. P-Diagram

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I. Qualitative Process Analysis

In Six Sigma DMAIC Projects, we use qualitative process analysis tools to:

Characterize process flow using a Process Map

E.g., Swim Lane, Value Stream Map, Process Map

These are typically done in Define or Measure Phase (and updated in the Improve/Control Phase)

Identify/brainstorm possible defect causes using:

Affinity Diagram

Cause-and-Effect Diagram

P-Diagram

These are typically done in Measure or Analyze Phase



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Qualitative Vs. Quantitative Process Analysis

Qualitative Process Analysis Good place to start/fast/low resource investment

Helps characterize the process to be improved

Provides list of potential variation causes by a knowledgeable TEAM

Quantitative Process Analysis Objective data-driven assessment of input-output relationships

Effective at separating vital few causes of variation (Key Inputs) versus trivial many – Prioritization

Effective qualitative analysis often reduces the amount of quantitative process analysis needed for improvement In Six Sigma projects, we want to combine past

experiences with objective data analysis!!

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II. Process Maps

Process maps– provide a visual representation of the flow High level system flow, or Detailed work flow within a system

Some Common Formats Used in Lean-Six Sigma: SIPOC Diagram Swim lane Process Flow Value Stream Map Process Mapping Diagram/Flow Chart

“You cannot improve a process until everyone agrees what the process is”



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Versions of a Process

At least Three Versions

Perceived State (e.g., in manuals)

Current Process (actual conditions)

Future State

(Post Improvement)

Note: The ideal process may be even simpler

Need to first determine the ‘AS-IS’ to Start Process Improvement

Common Process Map Formats

Swim Lane Diagram

Document overall process steps

Illustrates wastes of hand-offs

Detail Process Map

Illustrates key inputs needed

for detailed problem-solving

Value Stream Map

Product, Process, and

Information Flows with

% Value-add Time

SIPOC

Provides high level scoping of process

Process Flow

Department A

Department B

Department C

Step 1

Customer Start End

XX days XX days XX days

Step 2

Step 3

Step 4

Step 5Decision

Step 6A

Step 6B

Step 7

XX daysXX XX

Process Flow

Department A

Department B

Department C

Step 1

Customer Start End


Step 2

Step 3

Step 4

Step 5Decision

Step 6A

Step 6B

Step 7

XX daysXX XX

Step 1 Step 3DecisionStep 2

Step 4

FinalStep

Y11 Y12

Y31

Y41

KPOV-1KPOV-2

C1S1N1

S4N4

C51C52S5N51N52

Y – OutputC – Control FactorS – Standard ProcedureN – Noise Factor

Step 1 Step 3DecisionStep 2

Step 4

FinalStep

Y11 Y12

Y31

Y41

KPOV-1KPOV-2

C1S1N1

S4N4

C51C52S5N51N52

Y – OutputC – Control FactorS – Standard ProcedureN – Noise Factor

OUTPUTS

ProcessSteps

CUSTOMERS

SUPPLIERS

INPUTS

Boundary(Start of Process)

Boundary(Completion of Process)

OUTPUTS

ProcessSteps

CUSTOMERS

SUPPLIERS

INPUTS

Boundary(Start of Process)

Boundary(Completion of Process)

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8 hrs 32 hrs

40 120Tot = 444

VA = 14040 hrs

120

60 hrs

24

8 hrs 32 hrs

40 120Tot = 444

VA = 14040 hrs

120

60 hrs

24

8 hrs 32 hrs

40 120Tot = 444

VA = 14040 hrs

120

60 hrs

24

8 hrs 32 hrs

40 120Tot = 444

VA = 14040 hrs

120

60 hrs

8



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A. SIPOC Diagram Example – Loan Application Approval Process

Suppliers Inputs Process Outputs Customers

Appraisers Insurance

Companies Title

Companies

Type of Loan Interest Rates # Processors Loan Officer

Experience Lender

Guidelines

Complete and Accurate

Process Time < 30 days

Loan Fees

Mortgage

Customers

External

Under-

writers

Lending

Institutions

Regulatory

Agencies

Prepare

(Setup)

Loan

Process

Loan Underwrite

Loan

Close

Loan

Clear

Conditions

Note: Inputs/Outputs may be physical things/document or measurable requirements/criteria

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B. Swim Lane Diagram

Swim Lane Diagrams pictorially show key process steps, including

hand-offs and dependencies between functions (departments). First, Draw functional (departmental) “swim lanes” involved Map the process steps across the “swim lanes” (include start-end points)

Note: some steps may be done in series or parallel (occur simultaneously) Identify decision points/return steps to a prior function/department Finally, group steps by phases (e.g., between departmental handoffs). Show time in

each group/phase using timeline at the bottom (use average or time ranges)

Process Flow

Department A

Department B

Department C

Step 1

Customer Start End


Step 2

Step 3

Step 4

Step 5 Decision

Step 6A

Step 6B

Step 7

XX days XX XX

Functions/ Department

Timeline Phase 1 | #2 | #3 | #4 | #5 | #6



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Using Swim Lane Diagrams

Effective for large, complex processes where:

It may be difficult to get started using a detail map first

Multiple hand-offs exist between departments/functions

Sequence and time for process phases (group of steps) is important for downstream functions to meet their requirements

Common improvement include: Re-balancing/combining tasks to minimize unnecessary back-

and-forth handoffs between departments

Running non-dependent steps in parallel to reduce overall processing time (i.e., to eliminate wait time)

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Swim lane Diagram (Sales Order Fulfillment Example)

Any potential unnecessary handoffs?

Receive Order



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C. Value Stream Map (VSM)

Value stream – all of the actions (value and non-value added) required to get a product to the customer or complete a service Service flow ~ from order to delivery.

Design flow ~ from concept to launch.

Production flow ~ from raw material to finished goods.

Typically create VSM within a single facility and for common product families (i.e., with similar operations)

VSM are distinguished by their standard symbols used to show BOTH product (material) and information flows

VSM typically focus on an entire system flow (with both Material and Information Flow) – not just individual process Emphasis on flow leads to focus on the areas between processes

Flow improvements lead to streamlining or consolidation of processes, reduction in inventory, simpler flow paths and improved value add

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Value Stream Map Example – RFQ to Customer Review

RFQ – Request for Quote Process (Material and Information Flow)

Note: Case Study Simplified for Teaching Purposes

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8 hrs 32 hrs

40 120 Total = 444

VA = 140 40 hrs

120

60

(information flow)

(product flow)

P/T – Process Time VA – Value Add



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Value Stream Map Symbols (Source: “Learning to See”, M. Rother and J. Shook, The Lean Enterprise Institute, 1999.)

Process

Process - Activity Data Box Inventory

Operator Manual

Information Flow

Electronic Information

Flow

Finish Service To Customer

External Source

Supermarket (store inputs)

Push units to Next operation

External Ship Work Cell

http://www.strategosinc.com/value-stream-mapping-3.htm

MRP System Go See

- Examples of standard VSM symbols/terms

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VSM Wall Charts

While computer generated drawings using VSM symbols look nice, VSM’s usually are developed using pencil, paper, post-it notes!



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D. Detailed Process Mapping Diagram

More comprehensive version of a Conventional Flow Chart Show basic process flow (Flow Chart) including decisions (diamonds)

Add key process inputs (X’s) and outputs (Y’s) for various steps Inputs: Classify by controllable (C), standard procedure (S), noise (N) Note: Prior process outputs naturally become ‘inputs’ to next process

Most effective if show how the process actually works (“as-is”) versus “company manual” (include inspection, rework loops) Alternative Format: Vertical Process Map (see appendix)

Step 1 Step 3 Decision Step 2

Step 4

Final Step

Y11 Y12

Y31

Y41

KPOV-1 KPOV-2

C1 S1 N1

S4 N4

C51 C52 S5 N51 N52

C – Control Factor S – Standard Procedure N – Noise Factor

Use Standard ANSI/ISO Flow Chart Symbols

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Detail Process Map: Distribution Center

Swim lane Diagram

NVA – non value add

From the swim lane diagram, suppose we wish to examine the flow of orders through the distribution center



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Which Format is Best?

The main objective here is to describe the ‘as-is’ process to effectively communicate the current state and identify improvement opportunities

Making maps unnecessarily complicated or creating several maps that don’t add new useful information is waste!

So, use a mapping technique format which is: “As detailed as necessary for people to understand the

process and support continuous improvement”

Finally, regardless of format used, one needs to WALK the Process to ensure you capture the As-Is Process

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Current State Process Improvements - “Kaizen Bursts” on Process Maps

May use Kaizen Burst Symbol to highlight specific improvements needs Draw dashed boxes (‘loops’) around a group of steps that may be

rearranged/combined to improve efficiency)

Paperwork Redesign

Change Authority Levels

System Uptime

New Technology

Rearrange Flow

Combine Tasks

Add Pull Signal

Organize Workplace

Or, use ‘Post-it’ Notes on Wall Charts



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Swim lane - Sales Order Fulfillment - ‘Kaizen Bursts’ Improvements

Move Fax

Improve First Pass

Yield

Improve Sort

Track from Order Received

(Robust Direct Mail)

Rearrange Verify Step

Reassign Credit Check

to Sales Check/ Reconciliation

Eliminate Handoff

Receive Order

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Future State Map (Process Time ~ Reduced 3-4 Days)

Receive Order



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Making Improvements

Implement ‘quick wins’ first – now!

Order Fulfillment – MOVE Fax Machine to where it is primarily used

More significant changes may need to be tracked as projects

Order Fulfillment – Reassign Credit Check to Sales Department (requires training)

Lean-Six Sigma projects work well for improvement opportunities with unknown root causes and solutions (areas where a team does not completely agree on what to change)

Order Fulfillment – eliminate root causes of shipping errors

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III. Brainstorming Variation Causes

Following tools are used to perform structured brainstorming to identify potential root causes

E. Cause-and-Effect Diagram

F. P-Diagram

Other Structured Brainstorming Tools include:

Affinity Diagram

Cause-and-Effect Matrix



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Lean-Six Sigma Case Study

Project – Minor Construction Subcontractor Award

Problem: Current subcontractor review and award process was taking too long and did not efficiently use existing resources (lots of waste)

Formed an improvement team to identify causes/issues for time delays

Team reflected on personal experiences and conducted interviews of other users for input

Summarized their findings in a cause-effect diagram

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E. Cause & Effect Diagram (Ishikawa or Fishbone Diagram)

Given a Problem or ‘Effect’ (e.g., Late Contract Award Notices) use a Cause-Effect Diagram to visually show all possible causes/issues

One approach to help structure brainstorming around common categories is to start with the 4M’s (or 6M’s)

causes effect

Cause Branch

twig

twiglet

Effect

Effect – failure or problem

Cause Branch – Main Categories

(Example: 4M’s - man, method,

machine, material)

Twig – 1st Level Causes

Twiglets – 2nd Level Causes



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Cause-and-Effect Diagrams -- Main Causal Categories: 4 M’s

Most delay/defect causes fall into common categories: Man (personnel or people related issues)

Method (process related issues)

Machine (place or facility, equipment, IT system issues)

Material (product issues or inputs)

Other M’s Measurement system (or, include with machine)

Uncontrollable Environmental Issues (Mother nature)

Rather than these, may use the ‘grouping categories’ identified in Affinity Diagram Note: More common with non-manufacturing projects

(or 4 P’s)

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Man (Personnel)/Method

Man (Personnel)

Any potential cause related to people issues including differences in the way people perform tasks

Examples:

Lack of discipline (Staff not following standard procedure)

Lack of training

Lack of employee experience

High turnover

High tardiness

High absenteeism

Method (Process)

Any potential cause related to an ineffective process, procedure, policy, or their implementation

Examples:

Lack of standardized work

Lack of preventative maintenance

Lack of empowerment

Ineffective standard practice/procedure/policy

Poor scheduling process

Unclear instructions/procedures

Extra process steps (waste)

Over-processing

Non-value added tasks



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Machine and Material

Machines (Equipment) (Place) Any potential cause related to the

physical equipment, machines, or conditions at a workplace

Examples: Lack of Capacity

Lack of Equipment Capability

Lack of Equipment Availability

Poor office layout

Material (Inputs/Prior Process)

Any potential cause related to variation in process inputs (e.g., Raw Materials, Customers/Users)

Examples: Prior process outputs are incorrect

(e.g., out of specification) Late deliveries from suppliers Different Order Types Different Customer Characteristics

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Additional M’s: Measurement System and Mother Nature

Measurement System Any potential cause related to

differences in how data are collected or measured

Examples: Process/equipment used to measure

performance is: Not accurate Not repeatable/reproducible Does not mitigate data entry errors

Note: Sometimes one does not have an effective system to effectively judge if meeting requirements or not

E.g., trying to measure appearance

Mother Nature (External Environment) Any potential cause related to

an uncontrollable external or environmental condition

Examples: Catastrophe

Severe Weather

Major change in market condition

Change in a Government Regulation or Policy

Since we cannot eliminate these, what should we do?



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Issues with Brainstorming ‘Causes’

How many causes should one try to identify?

What should one do if a team cannot decide which ‘cause’ category an issue belongs (e.g., people vs. process issue)?

What should one do if a team identifies mostly ‘causes’ outside their span of influence?

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Cause-and-Effect (C&E) Diagram

Case Study: Minor Construction Project Award Contracts

EFFECT: Delays in awarding contracts

Next, team identified the following potential causes via brainstorming

TIP: For non-manufacturing projects, may prefer to use affinity diagram groupings for high level branch labels



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C&E Diagram Example (Minitab or other drawing software)

CAUSES Effect

Delays in

Awarding

Contracts

Environment Methods

Management

Equipment

Personnel

Unprofessional conduct

Too manysuppliers/customers

Play Favorities

Inflexible

Lack of manpower

Lack of IT Support

Paper Intensive

Too many decisions

Micro Mgmt

Award Decision

Award Recommend

KO Approval

Playing Email Tag

Playing Phone Tag

Lack of Tech EvalCriteria

No schedule

Lack of Adequate QCResources

Lack of BusinessProcess

Foreign Environment

US Standards

Cause and Effect Diagram

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The 5 Why’s

C&E Diagrams brainstorming may only identify broad causes (symptoms)

To find the root cause, we often need to keep asking ‘why’ to get from

Symptoms Root Cause To get to root causes, we often must:

Go to the Scene (workplace) Determine the facts Ask why, why, why, …

Then, put in a countermeasure to prevent re-occurrence

Apply the

5 Why’s*

Note: There is nothing sacred about the number “5” the objective is to keep asking Why until a root cause or actionable item is identified (may require more or less than “5”)



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Delays in

Awarding

Contracts

Environment Methods

Management

Equipment

Personnel

Unprofessional conduct

Too manysuppliers/customers

Play Favorities

Inflexible

Lack of manpower

Lack of IT Support

Paper Intensive

Too many decisions

Micro Mgmt

Award Decision

Award Recommend

KO Approval

Playing Email Tag

Playing Phone Tag

Lack of Tech EvalCriteria

No schedule

Lack of Adequate QCResources

Lack of BusinessProcess

Foreign Environment

US Standards

Cause and Effect Diagram

Cause-and-Effect Drill Down

Keep asking WHY?

Management

Award Decision Delays

Certain Managers take too long

No Consistent Review Criteria/

for Review

Lots of Information/

Criteria to Consider

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F. P-Diagram

The Parameter Diagram, or P-Diagram, is another tool for listing causes and documenting key input and output variables (X’s and Y’s) Key Output variables (Y’s) Input variables (materials, prior process outputs) (Advanced: Signal Factor) Control Factors (process settings) Uncontrollable Noise Factors

P-Diagrams help identify which ‘X variables’ to study

Control Factors

Uncontrollable (Noise) Factors

Input Variables

Output Variables

Y 1

Y m ...

PROCESS



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P-Diagram: Audit Process

Current State: ~ 30% complete and accurate, ~ 70% On-Time

Given the diagram below, identify potential analyses to study?

Audit Process

Control Factors Experience/Training of Staff System Guidelines IT System Software (information availability)

Inputs Client Information Domestic/Int’l location

Uncontrollable Noise Factors Change in government policy Different auditors

Outputs (Y’s) Complete and Accurate Reconcile Time, days

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Categorizing Noise Factors

Noise factors may be further classified into: External/Usage: factors related to small differences in

operator usage or external environment conditions. Examples: Usage: slight changes in customer requirements/expectations,

changes in how different customers use a product/service Environmental (Ambient Temperature, humidity, etc.)

Unit-to-unit: factors related to small differences in material properties or processing conditions from unit-unit. Examples: Material: variation in raw material properties (e.g., hardness) Mfg Processing Conditions (e.g., forming pressure, part

locating)

Deterioration and Wear: factors related to deterioration or wear over time. Examples: Amount of use (e.g., miles driven, # copies made) Loads (e.g., amount of weight a product is subjected)

Y LSL

6*sY-inherent

Noise sY-inherent (Common Cause )



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Control vs. Noise Factor

Classification of factors is situational (control vs. noise)

Consider environmental condition: Temperature

Here, we have different options:

Maintain as Noise Factor

Convert to Control factor (control the environment)

Decision to convert a ‘noise factor’ into a ‘control factor’ is often an economical one

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Summary

For DMAIC projects, start with Qualitative Process Analysis to force agreement on the ‘as-is’ process and help drive efficient data collection and analysis After identifying potential causes, may use Quantitative Analysis to

assess/confirm the contributions of various X variables on key outputs

Process Mapping Tools (High Level Detail Steps)

SIPOC, Swim Lane, VSM, Process Mapping Diagram/Flow Chart

To more effectively identify possible causes, we often use a structured framework 4 M’s (6 M’s) Cause-and-Effect Diagram

P-Diagram

(see Appendix for additional examples)



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Appendix 1:

Vertical Map

An alternative to a flow chart with decision loops is a ‘Vertical Process Map’

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Appendix 2: VSM - Manufacturing (Incoming Material to Ship per Master Schedule)

Product 1

Product 2

C/T 65 S..

Uptime 89%

C/O 30 M.

FTT 92%

C/T 120 S.

Uptime 84%

C/O 3.54 H.

(budget 2.5 H)

FTT 95%

CT 45 S..

Uptime 92%

C/O 20 M.

FTT 89%

C/T 60 S

Uptime 98%

C/O 30 M.

FTT 95%

1 Day

60 sec.

3 Day 5 Day

120 sec.

5 Day

65/45 sec.

14 Day

245 sec.

Next Customer Supplier.

Process B

I

I

I I

I

I

_5_/wk

Process A

Final Process

Process C

Material

Planning

6 week

Daily

6 week

Weekly

Weekly

Weekly

Weekly/Daily

Incoming Matl – Ship ~14 days

~Value-add time ~245 seconds



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Appendix 3: Injection Molding Process

Raw material inputs

pellets

Output: Part shape and % shrinkage

Process: use an injection molding machine to convert pellets into a product using a mold

-- Mold Cavity - Actual Part Size

Pellets

X Variables cooling time melt temperature fill time filling pressure mold wall temperature

nozzle diameter

Part

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P-Diagram Example – Injection Molding Process

Injection Mold Process

Controllable Process Settings cooling time (sec) melt temperature ( oF) screw speed (rpm) fill time (sec) filling pressure (MPa) nozzle diameter (cm) mold wall temperature ( oF) Inputs

Pellet Material Properties

Mold Shape

Uncontrollable Noise Variables % regrind pellets vs. virgin raw matl (5%, 10%) inherent variation in pellet size (small - medium)

Outputs (Y’s) Part Shrinkage (%)

qualitative process analysis

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