1. The ATAM – A Method for Architecture Evaluation
RiSE’s Seminars
Clements’s book :: Chapters 3
Frederico Durão
April 28, 2019

2. Summary Steps of ATAM The Phases of ATAM Step 1- 9; Phases 0 - 3
April 28, 2019

3. ATAM Steps :: Chapter 3 Summary of ATAM Steps Presentation
Present the ATAM
Present the business drivers
Present the architecture
Investigation and Analysis
Identify the architecture approaches
Generate the quality attributes utility tree
Analyze the architectural approaches
Testing
Brainstorming and prioritize scenarios
Reporting
Present the results
April 28, 2019

4. ATAM Steps :: Chapter 3 Step 1: Present the ATAM
The evaluation leader presents the ATAM’s steps to the stakeholders, besides techniques and the outputs of the evaluation
April 28, 2019

5. ATAM Steps :: Chapter 3 Step 2: Present the Business Drivers
A project decision maker presents a overview from a business perspective;
Business Context/Drivers Presentation (~12 slides / 45 minutes)
Description of the business environment, history…(~3-4 slides)
Description of the business constraints (~1-3 slides)
Description of the technical constraints (~1-3 slides)
Quality attributes requirements and from what business needs these are derived (~2-3 slides)
Glossary(1 slide)
April 28, 2019

6. ATAM Steps :: Chapter 3 Step 3: Present the Architecture
A lead architect or a architecture team presents the architecture in the appropriated level of detail;
In this presentation the architect should cover:
Technical constraints such as operating system, hardware, or middleware prescribed for use;
Other systems with which the system must interact;
Architectural approaches used to meet quality attribute requirements;
Architectural Views
Functional, concurrency, code and physical views
Architectural Presentation (~20 slides;60 minutes)
April 28, 2019

7. ATAM Steps :: Chapter 3 Step 4: Identify the Architectural Approaches
The architect identify the architectural approaches and styles
Architectural styles define important structures of the system and describe how the system can grow, respond to changes, withstand attacks, integrate with other system…
Example: Concurrent Pipeline Style
Sequence of data transformation;
Each component can be replaced or modified;
Elements can be reused elsewhere;
Evaluators can reason this style in terms of performance implications;
April 28, 2019

8. ATAM Steps :: Chapter 3
Step 5: Generate the Quality Attribute Utility Tree
The evaluation team works with the project decision maker to identify, prioritize, and refine the system most important quality attribute goals.
Utility trees translate the business drivers of a system into concrete quality attribute scenarios
Utility
Performance
Data Latency
(M,L) Minimize storage latency
(H,M) Deliver video in real time
Transaction Throughput
(M,M) Maximize average throughput to the authentication server
April 28, 2019

9. ATAM Steps :: Chapter 3
Step 5: Generate the Quality Attribute Utility Tree {2}
Scenarios
A short statement describing an interaction of one of the stakeholders with the system
User, maintainer, developer, product line manager
Useful in understanding run time qualities such as performance or availability
Structures
Stimulus – the user interaction
Environment – the system state
Response – how the system should respond to the system
Types
Use Case Scenarios
Growth Scenarios
Exploratory Scenarios
April 28, 2019

10. ATAM Steps :: Chapter 3
Step 5: Generate the Quality Attribute Utility Tree {3}
Use Case Scenarios
Describes a user’s intended interaction with the completed running system
The user wants to examine budgetary and actual data under different fiscal years without reentering project data (usability)
Growth Scenarios
Represent typical anticipated changes to a system
”Double the maximum number of tracks to be handled by the system and keep to 200 ms the maximum latency of track data to the screen” (Performance consequences)
April 28, 2019

11. ATAM Steps :: Chapter 3
Step 5: Generate the Quality Attribute Utility Tree {4}
Exploratory Scenarios
To expose the limits or boundary conditions of the current design;
“Improve the system’s availability from 98% to 99,999%”;
April 28, 2019

12. ATAM Steps :: Chapter 3 Step 6: Analyze the Architectural Approaches
At this point there is
A set of concrete quality requirements + a set of architectural approaches => Size up how well suited they are to each other;
Now the evaluation team can probe the architectural approaches that realize the important quality attributes.
Outputs of this Phase:
The architectural approaches or decisions relevant to each priority utility tree scenario;
The analyst questions associated with each approach;
The architect’s response to the questions;
The risks, nonriks, sensitivity points and tradeoff points identified;
At the end of this steps, the evaluation team should have a clear picture of the most important aspects of the entire architecture
April 28, 2019

13. ATAM Steps :: Chapter 3 Step 7: Brainstorm and Prioritize Scenarios
Use of Scenarios to:
Represent stakeholders interests;
Understand quality attribute requirements;
The evaluation team ask the stakeholders to brainstorm:
Use Case Scenarios
In this case stakeholder is an end user
Growth Scenarios
Modifications, changes in performance or availability
Exploratory Scenarios
Limits, dramatic new performance attributes
April 28, 2019

14. ATAM Steps :: Chapter 3
Step 7: Brainstorm and Prioritize Scenarios {2}
Once the Scenarios are collected…
The stakeholders merge the similar scenarios;
Then they vote for the most important scenarios (30% of total scenarios);
Each stakeholders casts his votes publicity;
The evaluation leader orders the scenarios;
The scenario “above the line” are selected to the subsequent steps;
The result is compared with the utility tree result;
Three things will happen after these steps:
The scenario will match essentially duplicated an already-existing leaf node;
The scenario will go into a new leaf of an existing branch;
The scenario will fit in no branch of the tree because it expresses a quality attribute no previously accounted for;
April 28, 2019

15. ATAM Steps :: Chapter 3 Step 7: Producers of system stakeholders
Definition
Interest
SW Architect
Person responsible for the architecture of the system and responsible for making tradeoffs among competing quality pressures
Moderation and mediation all of the quality concerns of the other stakeholder
Developer
Code or designer
Clarity of architecture description, high cohesion of parts, limited coupling of parts, clear interconnection mechanisms
Standard Expert
Developer responsible for knowing the details of standards (current and future) to which the software must conform
Separation of concerns, modifiability, interoperability
Project Manager
Person who allocates resources to teams, is responsible for meeting schedule and budget, interfaces with customer
Clear structuring architecture to drive team formation, work breakdown structure, milestones and deadlines, etc
Product Line manager or “reuse czar”
Person who has a vision for how this architecture and related assets can be reused further by the organization
Reusability, Flexibility
April 28, 2019

16. ATAM Steps :: Chapter 3 Step 7: Consumers of the system
Stakeholder
Definition
Interest
Customer
Purchaser on the system
Schedule of completion, over all budget, usefulness of the system, meeting customers expectations
End User
Use of the implemented system
Functionality, usability
Step 7: Servicers of the system
Stakeholder
Definition
Interest
System Administrator
Person running the system
Ease in finding the location that may arise
April 28, 2019

17. ATAM Steps :: Chapter 3 Step 8: Analyze the Architectural Approaches
The architect carry out the highest-ranked scenarios from step 7
The evaluation team performs the same activities as in Step 6
This Step is a testing activity: it is to be hopped that little new information will be uncovered
April 28, 2019

18. ATAM Steps :: Chapter 3 Step 9: Present the Results
The collected information from the ATAM needs to be summarized and presented back to the stakeholders
Verbal report + slides + more complete document written report including:
The architectural approaches documented
A set of scenarios and their prioritization
The set of attribute-based questions
The utility tree
The risk discovered
The nonrisks documented
The sensitivity points and tradeoff points found
April 28, 2019

19. ATAM Steps :: Chapter 3 The Phases of the ATAM Consist of 4 phases
Partnership
Preparation
Phase 1
Phase 2
Phase 3
April 28, 2019

20. ATAM Steps :: Chapter 3 The Phases of the ATAM – PHASE 0 Partnership
Involves the communication with the client, the sponsor of the evaluation
For that
The client should have a basic understanding of the evaluation method;
The client should describe the system and architecture being evaluated;
A contracted or statement of work should be negotiated and signed;
Issues of proprietary information should be resolved;
It’s a good time to talk about cost and benefits of architecture evaluation
April 28, 2019

21. Desirable Characteristics
ATAM Steps :: Chapter 3
The Phases of the ATAM – PHASE 0
Preparation
Forming the evaluation team;
Holding an evaluation team kickoff meeting;
Making the necessary preparations for Phase 1;
Set the roles for each member;
Role
Responsibilities
Desirable Characteristics
Team Leader
Sets up the evaluation; coordinates with client
Well-organized, with managerial skills
Evaluation Leader
Runs evaluation
Comfortable in front of an audience.
Questioner
Raises issues of architectural interest that perhaps the stakeholders have not considered
Good architectural insights; Experience with systems in similar domain.
April 28, 2019

22. ATAM Steps :: Chapter 3 The Phases of the ATAM – PHASE 1
Concentrates on Steps 1 through 6
Besides this steps the team needs to determine:
Whether the remainder of the evaluation is feasible and should proceed;
Whether more architectural documentation is required;
Which stakeholders should be present for Phase 2;
April 28, 2019

23. ATAM Steps :: Chapter 3 The Phases of the ATAM – PHASE 2
New stakeholders add the group that has participated of Phase 1;
Steps 1 to 6 are encored for the new stakeholders and;
Steps 7 to 9 are carried out.
April 28, 2019

24. ATAM Steps :: Chapter 3 The Phases of the ATAM – PHASE 3
The following tasks must be accomplished
Produce the final report
Cataloging what you did, found, concluded;
Use of the template;
Collect data for measurement and process improvement
Improve ideas about what worked particularly well and what could stand to be improved;
Data comes evaluation team and client;
Generation of surveys;
Update the artifact repositories
Record the cost and benefit information;
Stored scenarios produced;
Store a list of the analysis questions used;
April 28, 2019

25. The beauty of the life will never be realized by the luxury eyes
ATAM Steps :: Chapter 3
The beauty of the life will never be realized by the luxury eyes
April 28, 2019

26. References CLEMENTS, P. Software Product Line. Springer-Verlag, 2005.
April 28, 2019