Uml Diagrams In Software Engineering Pdf

Software engineering is a discipline utilizing Unified Modelling Language (UML) diagrams, which are accepted as a standard to depict object-oriented design models. UML diagrams make it easier to identify the requirements and scopes of systems and applications by providing visual models. In this manner, this study aims to systematically review the literature on UML diagram utilization in software engineering research. A comprehensive review was conducted over the last two decades, spanning from 2000 to 2019. Among several papers, 128 were selected and examined. The main findings showed that UML diagrams were mostly used for the purpose of design and modeling, and class diagrams were the most commonly used ones.

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Proceedings 2021 , 74, 13. https://doi.org/10.3390/proceedings2021074013 www.mdpi.com/journal/proceedings

Proceeding

UML Diagrams in Software Engineering Research:

A Systematic Literature Review

†

Hatice Koç *, Ali Mert Erdoğ an, Yousef Barjakly and Serhat Peker

Department of Management Information Systems, Izmir Bakircay University, 35665 Menemen, Turkey;

alimert.erdogan@bakircay.edu.tr (A.M.E.); ybarjakly@gmail.com (Y.B.); serhat.peker@bakircay.edu.tr (S.P.)

* Correspondence: hatcekoc@gmail.com

† Presented at the 7th International Management Information Systems Conference, Online,

9–11 December 2020.

Abstract: Software engineering is a discipline utilizing Unified Modelling Language (UML) dia-

grams, which are accepted as a standard to depict object-oriented design models. UML diagrams

make it easier to identify the requirements and scopes of systems and applications by providing

visual models. In this manner, this study aims to systematically review the literature on UML dia-

gram utilization in software engineering research. A comprehensive review was conducted over the

last two decades, spanning from 2000 to 2019. Among several papers, 128 were selected and exam-

ined. The main findings showed that UML diagrams were mostly used for the purpose of design

and modeling, and class diagrams were the most commonly used ones.

Keywords: software engineering; UML diagrams; literature review; systematic mapping; classifica-

tion

1. Introduction

Software enables organizations to adopt competitive differentiation and competitive

change because they can design, enhance, and adapt their systems, products, and services

to different market sectors, from manufacturing to art, and provide rapid and flexible

supply chain management [1]. However, every aspect of a system or application is deter-

mined to develop software. Therefore, software development is complex [2], and software

engineering has emerged as an engineering discipline which deals with any software

product from the early stages of system specification to the maintenance of this system or

application. It helps develop more reliable systems and decreases the cost for developing

the system [3].

Systematic literature review (SLR) is a research methodology, which makes it easier

to recognize, analyze, and interpret all existing studies [4]. Its objective is not only finding

all evidence for research questions but also contributing to improve evidence-based

guidelines [5]. It consists of three processes, which are planning, execution, and reporting.

Although these processes can consist of many steps depending on the research target, it

must include the steps of data retrieval, study selection, data extraction, and data synthe-

sis [6].

The Unified Modeling Language (UML) is also used to develop a system in software

engineering, which is a visual language to define and document a system. The require-

ments in scenarios that express how users use a system are shown with the UML. The

constraints of a system are also shown with the UML [4]. Hence, many researchers who

work as software engineers publish papers about how UML diagrams are utilized to de-

velop a system and contribute to the practice in order to advance the software engineering

discipline. In our study, SLR is used to understand which UML diagrams are popular,

why they are used, and which application areas are the most popular [2].

Citation: Koç, H.; Erdoğ an, A.M.;

Barjakly, Y.; Peker, S. UML

Diagrams in Software Engineering

Research: A Systematic Literature

Review. Proceedings 2021 , 74 , 13.

https://doi.org/10.3390/proceed-

ings2021074013

Published: 10 March 2021

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Proceedings 2021 , 74 , 13 2 of 8

The aim of this paper is to determine the situation and the future of UML diagrams

in the software engineering discipline. Thus, the research questions and keywords were

identified, and then publications between 2000 and 2019 were investigated using Google

Scholar. A total of 247 publications were found, and 128 of them included the following

UML diagrams: a class diagram, activity diagram, sequence/interaction diagram, state

machine diagram, system sequence diagram, deployment diagram, collaboration/com-

munication diagram, package diagram, object diagram, domain model diagram, and a

component diagram. These publications were classified in terms of the distribution years,

the publishers, the application areas, the usage purpose, and the types of UML diagrams.

A Microsoft Excel spreadsheet was used to store and analyze these data with bar graphs

and pie charts.

The rest of the paper is composed of three sections: Method, Results, and Conclusion.

In the Method section, the SLR process is investigated in detail, giving an outline for how

the methodology is applied and how the data is collected, which consists of four sub-

sections: Research Questions, Search Strategy, Inclusion and Exclusion Criteria, and Data

Extraction. The Results section expresses the findings for the included papers, which is

composed of five subsections, those being the answers to the research questions. The last

section includes discussion and comments on the findings, the situation, and the future of

this study.

2. Method

This study was conducted with the SLR methodology in three phases, consisting of

planning, exploring, and reporting, based on Kitchenham's theoretical framework. In this

framework, each of the phases can be broken down into many steps [6]. The planning

phase consists of the following steps: research questions, search strategy, inclusion and

exclusion criteria, and data extraction.

2.1. Research Questions

The objective of this paper is to investigate the use of various types of UML diagrams

against various variables. Several research questions were discussed, based on the previ-

ous literature and on common sense. The following are the basic research questions:

RQ1. What is the distribution of the number of publications by year?

RQ2. What is the distribution of the number of publications by publishers and publishing

types?

RQ3. What is the distribution of the publications according to the application areas?

RQ4. For which purposes are UML diagrams utilized in the publications?

RQ5. What are the most commonly used UML diagrams in the publications?

2.2. Search Strategy

This systematic literature review was performed through only the Google Scholar

search engine, using a set of predefined keywords (shown in Table 1). The base keyword

for the search strings was UML. This keyword was combined with the search strings listed

in Table 1. The years between 2000 and 2019 were determined to be the target period, and

relevant articles were downloaded that met th e general criterion, which included at least

one of the UML diagrams given in Table 2.

Table 1. Search strings.

Search Strings

System implementation Model for system

Software implementation Model for software

Application implementation Model for application

System design Architecture for system

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Software design Architecture for software

Application design Architecture for application

Framework for system System architecture

Framework for software System model

Framework for application System

ramework

Moreover, the process of forward and backward snowballing was undertaken to ex-

tend the research into two stages: using the original papers and then using the additional

papers that were found [7]. To do this, for each paper, the members of the team checked

the references in the paper, looking at the titles as well as the abstracts.

Table 2. Types of Unified Modeling Language (UML) diagrams.

Types of UML Diagrams

Use Case Diagram Communication/Collaboration Diagram

System Sequence Diagram Class Diagram

Domain Model (diagram) Component Diagram

Activity Diagram Deployment Diagram

State Machine Diagram Object Diagram

Sequence/Interaction Diagram Package Diagram

2.3. Inclusion and Exclusion Criteria

After a general research strategy and criteria, several relevant keywords were iden-

tified in terms of the research questions, the research was organized, and 247 publications

were found in the databases. A set of detailed criteria was created in order to select the

publications related to the research purpose. The inclusion and exclusion criteria were the

following:

• The publications must be published in the English language;

• The publications must be published between 2000 and 2019;

• The publications must include at the least one UML diagram.

Figure 1 displays the SLR process and the results of the inclusion and exclusion cri-

teria, and 52% of the downloaded publications—that is 128 publications—were included

in the study out of a total number of 247 papers.

Figure 1. Systematic literature review diagram.

2.4. Data Extraction

A data extraction process was conducted in order to deal with the research questions

and discover patterns and trends. For this purpose, a Microsoft Excel spreadsheet was

used to store and organize the data about the publications, which were the certain classi-

fication characteristics regarding the research questions such as type, publisher, usage

Proceedings 2021 , 74 , 13 4 of 8

purpose, and application area. Table 3 shows each classification characteristic and their

categories used in this study.

Table 3. The classification characteristics for the publications.

Characteristics Categories

Publication Type Journals, conferences

book chapters, and other academic publications

Publishers IEEE, ACM, Elsevier, Springer, and others

Goals Design, testing, implementation, and others

Application Health, industry and business, finance, service, computer science, education, and others

3. Results

This section explains the results of our literature review analyses on the publications

and includes the findings related to the resear ch questions. It is organized as subsections

in terms of the research questions.

3.1. RQ1. What Is the Distribution of the Number of Publications by Year?

Figure 2 shows the distribution of the publications between 2000 and 2019 through

four-year subperiods. The peak subperiod was between 2012 and 2015 at 25%, whereas

the subperiod between 2000 and 2004 was 23%, the subperiod between 2004 and 2007 was

20%, and the subperiod between 2016 and 2019 was 17%.

Figure 2. Distribution of papers based on four-year subperiods.

3.2. RQ2. What Is the Distribution of the Number of Publications by Publishers and Publishing

Types?

Figure 3 illustrates the distribution of the types of publications. It expresses that the

number of conference proceedings was 60, which was 47% of all publications, while the

book chapter publications had the lowest number and percentage of 4%, the number of

journal papers had a rate of 44%, and the percentage of other publications was 5%.

Figure 4 shows the number of publications in terms of the publishers. A total of 44

publications were published by IEEE, while Elsevier and Springer had the same number

of publications at 17. Moreover, 9 publications were published in ACM. Other publishers,

such as Taylor & Francis, Wiley, and others, had 41 publications.

2000–2003 2004–2007 2008–2011 2012–2015 2016–2019

Year Periods

Number of Studies

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Figure 3. The number of articles by publication type.

Figure 4. Distribution of articles by publisher.

3.3. RQ3. What Is the Distribution of the Publications According to the Application Areas?

Figure 5 expresses the distribution of publications for each application. The greatest

number of publications was mainly published for computer science and industry and

business applications, respectively, whereas the least number of articles was published

for finance and other application areas.

Figure 5. Distribution of publications by application area.

17 17

IEEE ACM Elseiver Springer Others

Publishers

Number of Studies

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3.4. RQ4. For Which Purposes Are UML Diagrams Utilized in the Publications?

More than two-thirds of the publications used UML diagrams for design purposes.

Other purposes for utilizing UML diagrams included testing and implementation or de-

velopment, with percentages of 18% and 13.3%, respectively. These can be seen in Figure

6 in detail.

Figure 6. Distribution of articles by purpose of UML diagram usage.

3.5. RQ5. What Are the Most Commonly Used UML Diagrams in the Publications?

The distribution for the number of each type of UML diagram is expressed in Figure

7. The least-used UML diagram was the component diagram, which had a rate of 0.7%.

However, the class diagram was the most commonly used one and was in 26.3% of all the

articles.

Figure 7. UML diagram usage in publications.

Table 4 gives information about the distribution of publications that either had only

one UML diagram type or more than one diagram type, and half of the studies contained

only one distinct diagram type; 18.8% of the publications included two or three different

types of diagrams, and 13.2% of the publications included four different types of UML

44 41

34 33

12 9 7 6 65 2

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diagrams. Only one publication contained five different types of UML diagrams, and 3%

of all the publications contained six different types of UML diagrams.

Table 4. Distribution of publications by UML diagram type usage.

The Number of UML Diagram Type Usages Count Percentage

1 59 46.1%

2 24 18.8%

3 24 18.8%

4 17 13.2%

5 4 3.1%

Total 128 100%

Apart from this table, when the diagrams under the category of Others were exam-

ined one by one, it was seen that single usages of the collaboration, component, and object

diagrams totaled zero; that is, they were never used individually in any publication.

Table 5 was formed to see the associations of the diagrams that were used in the same

publication. In other words, one can find the counts of publications that included two

specific diagrams in a study by looking at the junction square of the diagram names in the

table. Additionally, the bold numbers in the middle of the table give the total counts of

publications that included the related diagrams.

Table 5. The association matrix for the usage of UML diagram types.

Class Activity Use Case Sequence/Interaction State Machine Others

Class 71 22 23 19 19 27

Activity 22 44 16 9 8 16

Use Case 23 16 41 13 13 25

Sequence/Interaction 19 9 13 34 12 9

State Machine 19 8 13 12 33 13

Others 27 16 25 9 13 47

The five diagrams that had high usage rates in Figure 7 took place directly by their

names in the table. The other six diagrams were taken under the category of Others. Ac-

cordingly, it is obvious that high associations were correlated with the usage rates of the

diagrams. When comparing the differences between the associations together with the

total number of the publications, there were no significant differences, but when a class

diagram had 27 associations with the other diagrams in 71 total publications, the use case

for the other diagrams had 25 associations with 41 total publications, which was signifi-

cantly lower than the class diagrams. The activity diagrams also had less association with

the state machine diagrams compared with all the other diagrams.

4. Conclusions

The aim of this study was to present a comprehensive systematic literature review to

detect research trends on the use of UML diagrams within the past twenty years. For this

purpose, research questions were identified, and then a specific search strategy was fol-

lowed. All related studies published for a twenty-year period were systematically re-

viewed. A total of 128 publications were included and investigated in terms of the re-

search questions. Furthermore, the following main findings were discovered:

• The most common usage of UML diagrams in publications was class diagrams, while

sequence and state machine diagrams had the low rate of usage;

• Most of the publications were either conference proceedings or journals, whereas

there were only a few publications which were book chapters or other publication

Proceedings 2021 , 74 , 13 8 of 8

types. Furthermore, the largest number of articles using UML diagrams was pub-

lished by IEEE;

• Most of the articles were published for the computer science and industry application

fields, respectively;

• The articles utilized UML diagrams mostly for the purposes of designing and mod-

eling.

This research reviewed articles published between 2000 and June 2019 by searching

for a set of certain keywords. In further studies, it might be valuable to use a wider set of

keywords and extend the time span in order to provide a more comprehensive picture of

the literature related to this topic.

Author Contributions: Conceptualization, Y.B.; methodology, H.K.; analysis, A.M.E.; original draft

preparation, H.K., Y.B., A.M.E.; writing—review and editing, S.P.; supervision, S.P. All authors have

read and agreed to the published version of the manuscript.

Funding: This research received no external funding.

Conflicts of Interest: The authors declare no conflict of interest.

References

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... For use cases and class diagrams using UML (Unified Modeling Language). In object-based software development systems, UML (Unified Modeling Language) is often used because it can be used to visualize, define, construct, and document system development (Koç et al., 2021). ...

Web-based information technology is currently developing very rapidly. The utilization of web-based information technology is widely used in various types of work. One of them is the processing of inventory data. Talenta Store is a store engaged in the sale of mobile phone accessories. The management of inventory at Talenta Store is still not systematized. So that making inventory data with sales often makes mistakes and also owners sometimes find reports that are not appropriate. Therefore, a system that can support inventory data processing activities is made, namely the system Si-GIIS (Goods Inventory Information System) web-based. The development Si-GIIS system uses the FIFO (First in First Out) method design, which means that the goods purchased first will be sold first as inventory management. Si-GIIS was developed using the waterfall method and for system design using UML (Unified Modeling Language). In the test, Si-GIIS uses BlackBox testing with the final result that all systems work as expected. From the results of the satisfaction survey, it can be seen that 93% of employees and shop owners are very satisfied. Therefore, the development of the Si-GIIS system at the Talenta Store can be said to be successful and can be implemented into the inventory data processing system.

... In object-oriented analysis, we identify classes by examining usage scenarios, where classes are determined through nouns or noun phrases [1,2]. This is followed by analyzing classes with the intent of encapsulation (bundling data and methods) while still keeping data and operations separate. ...

Sabah Al-Fedaghi

The general acceptance of sequence diagrams can be attributed to their relatively intuitive nature and ability to describe partial behaviors (as opposed to such diagrams as state charts). However, studies have shown that over 80 percent of graduating students were unable to create a software design or even a partial design, and many students had no idea how sequence diagrams were constrained by other models. Many students exhibited difficulties in identifying valid interacting objects and constructing messages with appropriate arguments. Additionally, according to authorities, even though many different semantics have been proposed for sequence diagrams (e.g., translations to state machines), there exists no suitable semantic basis refinement of required sequence diagram behavior because direct style semantics do not precisely capture required sequence diagram behaviors; translations to other formalisms disregard essential features of sequence diagrams such as guard conditions and critical regions. This paper proposes an alternative to sequence diagrams, a generalized model that provides further understanding of sequence diagrams to assimilate them into a new modeling language called thinging machine (TM). The sequence diagram is extended horizontally by removing the superficial vertical-only dimensional limitation of expansion to preserve the logical chronology of events. TM diagramming is spread nonlinearly in terms of actions. Events and their chronology are constructed on a second plane of description that is superimposed on the initial static description. The result is a more refined representation that would simplify the modeling process. This is demonstrated through remodeling sequence diagram cases from the literature.

Sabah Al-Fedaghi

The UML sequence diagram is the second most common UML diagram that represents how objects interact and exchange messages over time. Sequence diagrams show how events or activities in a use case are mapped into operations of object classes in the class diagram. The general acceptance of sequence diagrams can be attributed to their relatively intuitive nature and ability to describe partial behaviors (as opposed to such diagrams as state charts). However, studies have shown that over 80% of graduating students were unable to create a software design or even a partial design, and many students had no idea how sequence diagrams were constrained by other models. Many students exhibited difficulties in identifying valid interacting objects and constructing messages with appropriate arguments. Additionally, according to authorities, even though many different semantics have been proposed for sequence diagrams (e.g., translations to state machines), there exists no suitable semantic basis refinement of required sequence diagram behavior because direct style semantics do not precisely capture required sequence diagram behaviors; translations to other formalisms disregard essential features of sequence diagrams such as guard conditions and critical regions. This paper proposes an alternative to sequence diagrams, a generalized model that provides further understanding of sequence diagrams to assimilate them into a new modeling language called thinging machine (TM). The sequence diagram is extended horizontally by removing the superficial vertical-only dimensional limitation of expansion to preserve the logical chronology of events. TM diagramming is spread nonlinearly in terms of actions. Events and their chronology are constructed on a second plane of description that is superimposed on the initial static description. The result is a more refined representation that would simplify the modeling process. This is demonstrated through remodeling sequence diagram cases from the literature

BackgroundIn 2004 the concept of evidence-based software engineering (EBSE) was introduced at the ICSE04 conference.AimsThis study assesses the impact of systematic literature reviews (SLRs) which are the recommended EBSE method for aggregating evidence.MethodWe used the standard systematic literature review method employing a manual search of 10 journals and 4 conference proceedings.ResultsOf 20 relevant studies, eight addressed research trends rather than technique evaluation. Seven SLRs addressed cost estimation. The quality of SLRs was fair with only three scoring less than 2 out of 4.ConclusionsCurrently, the topic areas covered by SLRs are limited. European researchers, particularly those at the Simula Laboratory appear to be the leading exponents of systematic literature reviews. The series of cost estimation SLRs demonstrate the potential value of EBSE for synthesising evidence and making it available to practitioners.

The quality of conceptual models directly affects the quality of the understanding of the application domain and the quality of the final software products that are ultimately based on them. This paper describes a systematic literature review SLR of peer-reviewed conference and journal articles published from 1997 through 2009 on the quality of conceptual models written in UML, undertaken to understand the state-of-the-art, and then identify any gaps in current research. Six digital libraries were searched, and 266 papers dealing specifically with the quality of UML models were identified and classified into five dimensions: type of model quality, type of evidence, type of research result, type of diagram, and research goal. The results indicate that most research focuses on semantic quality, with relatively little on semantic completeness; as such, this research examines new modeling methods vs. quality frameworks and metrics, as well as quality assurance vs. understanding quality issues. The results also indicate that more empirical research is needed to develop a theoretical understanding of conceptual model quality. The classification scheme developed in this paper can serve as a guide for both researchers and practitioners.

Dave A. Thomas

Modeling is at the core of many disciplines, but it is especially important in engineering because it facilitates communication and constructs complex things from smaller parts. Model engineering or model-driven development, treats software development as a set of transformations between successive models from requirements to analysis, to design, to implementation, to deployment. We discuss UML and MDA tools for developing software models. We also discuss domain specific languages, domain-oriented programming, platform-specific models and model engineering.

Samireh Jalali
Claes Wohlin

Systematic studies of the literature can be done in different ways. In particular, different guidelines propose different first steps in their recommendations, e.g. start with search strings in different databases or start with the reference lists of a starting set of papers. In software engineering, the main recommended first step is using search strings in a number of databases, while in information systems, snowballing has been recommended as the first step. This paper compares the two different search approaches for conducting literature review studies. The comparison is conducted by searching for articles addressing "Agile practices in global software engineering". The focus of the paper is on evaluating the two different search approaches. Despite the differences in the included papers, the conclusions and the patterns found in both studies are quite similar. The strengths and weaknesses of each first step are discussed separately and in comparison with each other. It is concluded that none of the first steps is outperforming the other, and the choice of guideline to follow, and hence the first step, may be context-specific, i.e. depending on the area of study.

Barry Boehm

In response to the increasing criticality of software within systems and the increasing demands being put onto 21st century systems, systems and software engineering processes will evolve significantly over the next two decades. This paper identifies eight relatively surprise-free trends—the increasing interaction of software engineering and systems engineering; increased emphasis on users and end value; increased emphasis on systems and software dependability; increasingly rapid change; increasing global connectivity and need for systems to interoperate; increasingly complex systems of systems; increasing needs for COTS, reuse, and legacy systems and software integration; and computational plenty. It also identifies two "wild card" trends: increasing software autonomy and combinations of biology and computing. It then discusses the likely influences of these trends on systems and software engineering processes between now and 2025, and presents an emerging scalable spiral process model for coping with the resulting challenges and opportunities of developing 21st century software-intensive systems and systems of systems. © 2006 Wiley Periodicals, Inc. Syst Eng 9: 1–19, 2006