Hironori Washizaki, Atsuo Hazeyama, Takao Okubo, Hideyuki Kanuka, Shinpei Ogata, Nobukazu Yoshioka, “Analysis of IoT Pattern Descriptions,” 2021 IEEE/ACM 3rd International Workshop on Software Engineering Research and Practices for the IoT (SERP4IoT 2021) , co-located with the 43rd ACM/IEEE International Conference on Software Engineering (ICSE 2021), June 3, 2021, online.

1. Analysis of IoT Pattern Descriptions
Hironori Washizaki*, Atsuo Hazeyama, Takao Okubo,
Hideyuki Kanuka, Shinpei Ogata, Nobukazu Yoshioka
* Waseda University, Tokyo, Japan
washizaki@waseda.jp
SERP4IoT 2021, June 3rd, 2021

2. IoT Gateway Event Subscription
• Inspired by: “Publish/Subscribe” [..]
• Related patterns: “D2D REST Request/Response”
• Intent: D2D gateway allows data forwarding (any type). Flexibility in
the D2D layer is achieved by decoupling [..]
• Problem&Solution: To provide interoperability between two
heterogeneous IoT devices, the solution should establish
bidirectional, asynchronous communication with the ability to
publish, filter and consume data. [..]
• Applicability: Used within event-based communication, when
asynchronous data is to be pushed/pulled to/from the gateway.
2
R. Tkaczyk, K. Wasielewska, M. Ganzha, M. Paprzycki, W. Pawlowski, P. Szmeja, and G. Fortino, “Cataloging design patterns for
internet of things artifact integration,” in 2018 IEEE International Conference on Communications Workshops, ICC Workshops 2018
IoT Gateway
IoT Device
/ Application
IoT Device
/ Application
publish IoT Device
/ Application
IoT Device
/ Application
subscribe
Virtual part
Physical part

3. IoT needs patterns!
• Bridge between abstract vision and
concrete cases, instructions and tools
– Documenting and reusing solutions as well as
problems under specific contexts
– Getting consistent architecture
3
Vision
Case
Tool
FW
Instruction
?
？
• Common language among stakeholders
– Software engineers, hardware engineers,
communication network engineers, domain
experts, data scientists …

4. Pattern forms (template)
• GoF and POSA are two well-accepted
forms that provide standard templates.
• Canonical is the primary form for
combining other famous forms such as
the Coplien form.
4
GoF book POSA book
IoT Gateway Event Subscription
• Inspired by: [..]
• Related patterns: [..]
• Intent: [..]
• Problem&Solution: [..]
• Applicability: [..]

5. Motivation and research questions
• Previously, we identified 61 IoT architecture and design patterns
through a rigorous systematic literature review (SLR). [IoTJ’20]
• IoT patterns occasionally adopt a unique description and form.
• RQ1. What kinds of sections do IoT pattern descriptions adopt?
– Collecting the different sections used in IoT pattern descriptions
• RQ2. What forms do IoT pattern descriptions adopt?
– Measuring the conformance degree to identify the most likely form
among three common forms: GoF, POSA, and Canonical forms
• RQ3. Do IoT-specific description sections exist?
– Identifying all sections used to describe IoT patterns that are excluded in
the common forms
• RQ4. How do IoT pattern descriptions differ from other patterns?
– Comparing sections common in IoT pattern descriptions with those in
security pattern descriptions
5
[IoTJ’20] H. Washizaki, S. Ogata, A. Hazeyama, T. Okubo, E. B. Fernandez, N. Yoshioka, “Landscape of
Architecture and Design Patterns for IoT Systems,” IEEE Internet of Things Journal, Vol. 7, No. 10, 2020

6. 16
0 1 0
1213
5
0 0
13
0 0 1
0
5
10
15
20
0 2 4 6 8 10 12
Number
of
patterns
Number of sections in single…
RQ1. What kinds of sections do IoT pattern descriptions adopt?
• 25% of IoT patterns are not well described.
• “Related Pattern (See also)” is the most common section.
– Many IoT patterns can be utilized to constitute large solutions.
• “Implementation” is also often used.
– The contents vary drastically between patterns.
6
Number of sections per pattern

7. RQ2. What forms do IoT pattern descriptions adopt?
• We define the conformance degree (CD), where:
– P : Set of sections described in the target pattern
– F : Set of sections constituting a common form
• Result: POSA 14 patterns (in 2 papers), GoF 6 patterns (1), Canonical 4
patterns (1), 21 unidentified patterns
– Only about half of well-documented IoT patterns adopt common pattern forms.
– Communities should adopt common pattern.
7
IoT Gateway Event Subscription
• Inspired by: [..]
• Related patterns: [..]
• Intent: [..]
• Problem&Solution: [..]
• Applicability: [..]
CDIoTGateway, POSA = 5 /12 = 0.42

8. RQ3. Do IoT-specific description sections exist?
• “Description” is used for two different
purposes: abstract description of the
entire pattern and detailed explanation
of solutions.
• “Inspired by” is used to specify other
general patterns as a basis of the target
IoT pattern.
– IoT patterns are often identified as
special cases of existing non-IoT patterns.
– E.g., “IoT Gateway Event Subscription” as
an extension of “Publish-Subscribe”
• “UML representation” describes
structural and behavioral models of
solutions in the form of UML diagrams
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The IoT and pattern communities should further investigate
missing IoT-specific aspects, and document accordingly.

9. RQ4. How do IoT pattern descriptions differ from other
types of patterns?
• “Problem,” “Solution,” “Related Patterns,” and “Known Uses”
are common in IoT patterns and Security patterns [Bunke14].
• “Consequences” is less common to IoT pattern descriptions.
– Since many IoT patterns address quality attributes related to IoT, the
authors of IoT patterns should explicitly document quality impact.
9
[Bunke14] M. Bunke, “On the description of software security patterns,” EuroPLoP 2014
Problem 84%
Solution 84%
Related Patterns 82%
Consequences 79%
Known Uses 74%
・・・
Implementation 45%
・・・
Intent 37%
Related Patterns 64%
Problem 51%
Solution 51%
Implementation 47%
Intent 44%
・・・
Known Uses 31%
・・・
Consequences 13%
Top sections in Security patterns (N=38)
Top sections in IoT patterns (N=45)

10. Conclusion and future work
• We conducted an in-depth analysis of 61 IoT
pattern descriptions.
– 25% of IoT patterns are not well described.
– The high number of adoptions of “Related Pattern”
indicates that many IoT patterns can be utilized to
constitute large solutions.
– “Inspired by” is used to specify general patterns as a
basis of the target IoT pattern.
– Communities should further investigate IoT-specific
aspects to be documented.
• We plan to
– compare IoT patterns with other types of patterns.
– investigate the impact of maturity degree of IoT pattern
descriptions on the development and operation using
experimental and empirical studies.
10