A VISUAL METHODOLOGY

FOR THE DESIGN OF COURSE CONTENTS

A Case Study in Communications Software

Jes´us Mart´ınez

Computer Science Departament, University of M´alaga, Spain

Keywords:

Content development, UML, Model-driven architecture.

Abstract:

This paper proposes a novel methodology for the design of courses visually. Our method takes borrowed

techniques from Software Engineering such as the Uniﬁed Modeling Language (UML) and Model-driven

Architecture (MDA). The main goal of this approach is the creation of generic courses that may be reﬁned

later depending on different educational contexts. Therefore, teachers will have automatic support from tools

in order to schedule lectures, activities or resources. This experience is being carried out in the context of a

Communications Software course for different undergraduate degree programs at the University of M´alaga.

1 INTRODUCTION

During the last thirty years, distributed services have

evolved in the same way as computer networks and

protocols have. Part of the success of these newly

emerging applications is due to the use of high-level

standards and middleware which allow developers to

abstract speciﬁc features of transport protocols and

execution platforms. However, the availability of

these resources may lead to the design of poor per-

formance communications software (due to the abuse

of application protocols and Web Services, misunder-

standing of the Socket API,...). It is worth noting that

many networked applications are thought to be efﬁ-

cient only because less time was spent on their devel-

opment, thus some important details regardingrobust-

ness and scalability may not have been considered.

Our students must understand that in order to design

good communications software they will have to ob-

tain a good founding in Concurrent Programming,

Protocol Engineering and Software Engineering. For

this reason, it is important that institutions and teach-

ing staff must carefully consider what, when, and how

to teach these subjects.

For instance, a Communications Software syl-

labus usually focuses on different learning objectives

if it belongs to different programs (Computer Engi-

neering, Electrical Engineering), degrees (undergrad-

uate, masters of science) and also depends on the

number of hours allocated to the course. Moreover,

there are other factors that inﬂuence coursework plan-

ning, for instance, if the students skills on program-

ming languages are not as expected or if they lack an

in-depth knowledge of operating systems or concur-

rency. In these cases, there will be more introductory

lectures, usually at the expense of other material later

due to lack of time. Therefore, the original syllabus

becomes obsolete. This situation applies to some of

these courses in the Electrical Engineering and Com-

puter Engineering programs existing in the Univer-

sity of Malaga where students may have taken dif-

ferent courses previously: rigid planning signiﬁcantly

affects the academic performance of some students.

Designing a course taking all these constraints

into consideration would be a challenge for any

teacher so it would be more beneﬁcial to handle the

learning objectives, lectures and activities at different

levels of detail (from more general to more speciﬁc

ones), where each level would deal with speciﬁc re-

quirements according to the constraints considered.

Undoubtedly, in order to obtain a model for design-

ing courses in this way, we should apply a rigorous

methodology to support the description, manipulation

and reﬁnement of each level, until the most suitable

course is obtained.

This paper presents a visual approach for the de-

sign of contents and learning activities for a course.

We will use Software Engineering methods and tools

such as the Uniﬁed Modeling Language (UML) (Ob-

ject Management Group, c) to describe subjects, con-

434

Martínez J. (2010).

A VISUAL METHODOLOGY FOR THE DESIGN OF COURSE CONTENTS - A Case Study in Communications Software.

In Proceedings of the 2nd International Conference on Computer Supported Education, pages 434-437

DOI: 10.5220/0002792204340437

 SciTePress

Object Oriented Programming

Design Patterns

Procedural Programming

Communication Patterns

Concurrent Programming Operating Systems

Protocol Engineering

Client/Server

TCP/IP

<<import>>

Figure 1: A visual diagram describing relationships among subjects.

cepts and their relationships visually. We will also use

UML to deﬁne activities and their sequencing during

the course. It is worth noting that there are only a

few approaches which have employed UML to de-

scribe some concepts related to education (Nodenot

et al., 2004; Marlowe et al., 2005). We also propose

to design courses in a generic way, that is, we will

use some guidelines available in the Model-drivenAr-

chitecture (MDA) (Object Management Group, a) to

transform a generic (and visual) UML course in order

to obtain speciﬁc subjects according to different ed-

ucational contexts or the student backgrounds. MDA

transformation rules will also be useful to obtain other

resources from our visual courses, such as documen-

tation for teachers, subject coordinators or students

(the syllabus, mandatory exercises, etc.). Courses de-

signed using this approach are stored in XML for-

mat, it being possible to manipulate them automati-

cally using well-known CASE tools, such as Eclipse

(The Eclipse Foundation, 2009).

2 APPLYING UML AND MDA

FOR DESIGNING COURSES

Communications Software and related subjects are

part of the Computer and Electrical Engineering cur-

ricula available in the University of M´alaga. This

section presents a case study for the design of Com-

munications Software related courses using UML and

MDA concepts in two steps. First, we will deﬁne

subjects, their concepts and relationships in a visual

(and generic) way. We will also describe a set of

activities to be carried out (sequentially or in paral-

lel) within every subject. Second, we will deﬁne the

appropriate transformation rules to obtain a speciﬁc

curriculum (for concepts and activities), taking into

account different educational contexts or the student

backgrounds.

2.1 Designing Generic Courses

In order to use our visual approach, subjects in the

curriculum are ﬁrst selected following the Univer-

sity guidelines. Once we have the set of learning

objectives to cover, we will design generic subjects,

the concepts to cover and activities. Initially, we

will depict high-level Class Diagrams to model these

subjects which will include contents units. We will

also indicate relationships between subjects (includ-

ing those belonging to other existing curricula in the

program). Fig. 1 shows an example of this descrip-

tion, where each subject constitutes a UML pack-

age. In the ﬁgure, available packages refer to Socket

TCP/IP programming, Client/Server architecture or

speciﬁc design patterns for communications (Schmidt

and Huston, 2003) contents. The subject called Proto-

col Engineering is based on teaching typical concepts

needed to build protocol stacks in layers: messages,

queues, timers or state machines, among others. The

relationship between subjects (or content units) will

be explicitly depicted in the diagram, beginning with

the basis set by Procedural Programming, taught in

the ﬁrst courses. An

<<import>>

relation indicates

that one subject requires the previous knowledge ob-

tained in another one. This dependence relationship

is clariﬁed inside each subject/package using a Class

Diagram where topics or concepts will be described

as UML classes, allowing the connections with pre-

vious concepts through class relationships. Fig. 2

depicts a simpliﬁed scenario where some classes de-

A VISUAL METHODOLOGY FOR THE DESIGN OF COURSE CONTENTS - A Case Study in Communications

Software

435

IPC

(Concurrent Programming)

Comm. End Point

+IP addr

+port

UDP

+send()

+reception()

TCP

+buffering

+OOB data

+send()

+reception()

Passive TCP

+backLog()

+accept()

Socket

+init()

+close()

Active TCP

+connection()

Net DB

Figure 2: A generic model to describe Socket concepts.

ﬁne concepts of the TCP/IP subject. The ﬁgure shows

the concept of Socket, which is derived from a previ-

ous concept called IPC (inter-process communication

concept), which was learned previously within the

Concurrent Programming subject. The Socket con-

cept will be specialized in UDP and TCP sockets. For

each class, the attributes are used to list the main im-

portant features of the concepts. For example, when

deﬁning a Communication End Point, one IP ad-

dress and one transport port are required. Procedural

concepts are included as operations within the class.

We have included the basic operations that students

will use when working with Sockets. The diagram in

ﬁg. 2 also uses more UML notation for our descrip-

tion purposes. For instance, classes in italics (UML

abstract classes) will now mean that the concepts they

represent need to be extended/reﬁned by other classes

(that is, they need more explanation). This reﬁnement

is shown in ﬁg. 2, where the IPC concept is special-

ized as a Socket and, then as a TCP socket, which

is also specialized in a passive and active one. As

commented before, this example describing a subject

can be considered a generic model, and can be reﬁned

later.

2.2 Scheduling Lectures and Activities

Once we have designed our subjects and concepts us-

ing Class Diagrams, the next step in our methodol-

ogy consists of organizing all activities which lead

to obtaining the proposed learning objectives. Thus,

we will add UML Activity Diagrams to our general

model. Fig. 3 shows an example of a diagram pre-

pared to be used for teaching the concepts related to

the TCP/IP subject. An action could be fully iden-

tiﬁed by its name. Furthermore, control ﬂow makes

it easy to move forward through the syllabus. For ex-

Application data framing

Basic usage

TCP-UDP relationship

Network queries

TCP basic exercise UDP basic exercise

Sockets Definition

Figure 3: Sequence of activities involved in a subject.

ample, if we are now in the action called Basic Usage,

then we will execute two exercises in parallel, for ex-

ample, one exercise programmingTCP sockets (in the

lab) and another one programming UDP sockets (at

home).

2.3 Obtaining Speciﬁc Courses

In our methodology, an educational itinerary will be

the result of a (parameterizable) transformation pro-

cess applied to a generic course in order to obtain an-

other more concrete. Therefore, the teacher could be

able to react to different constraints such as the stu-

dent backgrounds, and subsequently preparing differ-

ent learning strategies (modiﬁcations of the generic

elements designed in our visual subject). This trans-

formation process will mean the existence of an MDA

transformation template, which will be applied to our

existing general models. The model obtained after

the transformation will be a speciﬁc one, now includ-

ing modiﬁcations in the original diagrams. A typical

scenario of application for an educational itinerary,

would consists of insertions, modiﬁcations and re-

movals of actions in existing Activity Diagrams, or

content features and explanations in Class Diagrams.

In the proposed Communications Software course, we

have considered at least three different itineraries:

one that uses the C language and a UNIX platform,

one that uses multiplatform C++ libraries and spe-

ciﬁc Design Patterns (Schmidt and Huston, 2003) and

the last one using the Java language. For instance,

ﬁg. 4 shows a partial view of applying the so-called

C/UNIX educational itinerary to the Class Diagram

for TCP/IP concepts of ﬁg. 2. In the ﬁgure, ba-

sic concepts on the left part become the ones on the

right, which specify that the concepts will focus on

CSEDU 2010 - 2nd International Conference on Computer Supported Education

436

TCP

+PUSH

+URGENT

+send()

+recv()

TCP

+buffering

+OOB data

+send()

+reception()

Passive TCP

+backLog()

+accept()

Passive TCP

+listen()

+accept()

Active TCP

+connection()

Active TCP

+connect()

Figure 4: Obtaining a speciﬁc learning context.

Figure 5: Using a proﬁle with our elements.

Berkeley Sockets for UNIX systems (and its common

interface with send(), recv(), connect(), listen(), ac-

cept(), and other system calls). In the same way, these

itineraries could be used to modify basic activities for

concrete actions (lectures, practical exercises oriented

to programming languages and platforms) along with

the whole course planning.

2.4 Supporting Tools

In order to help automatic tools to detect and manipu-

late our proposed visual elements (subjects, concepts,

activities,...), we are developing a UML Proﬁle. This

UML mechanism deﬁnes a so-called Domain Spe-

ciﬁc Language (DSL), giving the possibility to rede-

ﬁne the semantics of any UML elements as our ap-

proach requires. Therefore, UML elements redeﬁned

using a Proﬁle will include speciﬁc stereotype tags to

mark them and guide other processing tools such as

the transformation engines. The most suitable stereo-

types for our approach are being tested at this mo-

ment. Fig. 5 show an example of some stereotypes

proposed. The left column depicts a special package

with the

<<subject>>

semantics that could contain

some

<<concept>>

classes, whereas the right column

depicts two possible activities including a lecture and

homework. These activities also include tags related

to their duration (in minutes) and marking (valid for

the homework). It is worth noting that the use of pro-

ﬁles has also been used in other e-Learning contexts,

as presented in (Nodenot et al., 2004).

Therefore, a tool which supports our approach

will have to include graphical interfaces to load, edit

and save visual courses (stored in XMI format (Ob-

ject Management Group, b)) and will have also to in-

clude features to create educational itineraries, where

target elements to transform could be speciﬁed easily.

These itineraries should be described visually in order

to hide the complexities of a transformation language

from teachers. Currently, we are implementing this

graphical tool in Eclipse.

2.5 Conclusions and Future Work

This paper has presented a visual methodology for

the design of courses and curricula using UML and

MDA. Our aim is also to facilitate the coordination

tasks and to detect inconsistencies and overloads of

work on student activities during the courses.

ACKNOWLEDGEMENTS

The author would like to thank ETSI Inform´atica and

the University of M´alaga for their support during this

experience.

REFERENCES

Marlowe, T., Ku, C., and Benham, J. (2005). Acm sigcse

bulletin, vol-37(1). In Design patterns for database

pedagogy: a proposal.

Nodenot, T., Marquesuzaa, C., Laforcade, P., and Sal-

laberry, C. (2004). Model based engineering of learn-

ing situations for adaptive web based educational sys-

tems. In Proc. 13th WWW Alternate.

Object Management Group. MDA Guide Version 1.0.1.

Object Management Group. MOF 2.0/XMI Mapping,

v2.1.1.

Object Management Group. UML Version 2.1.2.

Schmidt, D. and Huston, S. (2003). C++ Network Pro-

gramming Volume 2: Systematic Reuse with ACE and

Frameworks. Addison-Wesley.

The Eclipse Foundation (2009). Eclipse IDE. Available at

http://www.eclipse.org/.

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Software

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