Virtual Learning Environment for Digital Signal Processing

Virtual Learning Environment for Digital Signal Processing 1

Yadisbel Martinez-Cañete1, Sergio Daniel Cano-Ortiz1, Frank Sanabria-Macias , Reinhardt Langmann2, Harald Jacques2, Pedro Efrain Diaz-Labiste1 Universidad de Oriente, Santiago de Cuba, Cuba, {scano,ymartinez, fsanm77, pedro.diaz}@uo.edu.cu 2 University of Applied Sciences Duesseldorf, Germany {scano,ymartinez,lienys}@uo.edu.cu

Abstract. At the Electrical Engineering Faculty of the UO in Santiago de Cuba, for the increase and improvement of students' knowledge in the subject Digital Signal Processing difficulties are detected in the learning of this subject in Biomedical, Telecommunications and Electrical careers in the Faculty, due to the high degree of mathematical theoretical concepts that they require, which has caused lack of motivation in the students and low academic results. The virtual learning environment is a web application developed in the Django framework, written in Python, which respects the design pattern known as Model-View-Controller, as a relational database management system, Sqlite is proposed, due to its speed, reliability and ease of use, multiplatform and multi-user. Using the observer pattern for the management of student activities, through which students can check the progress of the assimilation of the contents in each of the topics of the subject. Two user roles are considered for the system, teachers´ role that is responsible for the management of educational resources, such as topics, videos, questions, or other reference materials, and students´ role, who interact with each of the resources, registering the time and answers to the questions, for a post-top statistical analysis that can be shown to the student or the teacher. Keywords: digital signal processing, web technology, virtual learning environment

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Introduction

Internet is becoming an important educational resource thanks to the capacity it offers us to complement the traditional format classes in the classroom environment with the possibility of allowing access to information online. The limitations of time and place have disappeared. In addition to this possibility, it is important to take into account the effect of the interactivity that a computer tool can have on the learning process. In this sense, it is known that interactivity is an important and probably essential attribute of any learn-

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ing technique that pretends success, that learning is more effective when the student can control the exchange of information. The information and communication networks, through the Internet, break barriers of time and space to develop teaching-learning activities. Information and Communication Technologies (ICT) is the main tool that organizations and educational institutions have begun to use to offer courses and virtual study programs through the web [1]. In short, the increase in training needs is calling for the creation of new networks and forms of access to education. In this sense, new technologies to support digital education are becoming one of the strategies used to do so. One of the most representative examples of the teaching media used on the web are the tutorials, which support the student's learning process, as they guide him through a series of activities that he must carry out on his own [2], [3], [4]. Studies conducted in the early nineties at the University of Deakin (Australia) [5] showed that students who had used interactive and multimedia learning techniques had a 55% gain over those students who received the classes in the traditional teaching environment. Other significant figures showed that the students learned the material 60% faster and the retention of knowledge after 30 days was between 25 and 50% higher. In another study carried out at the Acadia University (Canada) [6] in students of an introductory physics course in the first year of university teaching, it can be seen that both the results and satisfaction at the end of the students' course. That they used interactive tools were clearly superior to those of those who received the course with classical techniques. It is also worth noting the usefulness that this tool can have in the classroom itself, by allowing the teacher to use other materials than usual and in this way to speed up the classes and attract the attention of the students. In this sense the author in [7] has been able to verify that by using the tutorial in the classroom the attention increased and the comprehension improved, and therefore the learning. Signal processing is an area of Electronic Engineering that focuses on the representation, transformation and manipulation of signals, and the information they contain. Students in experimental and technical areas must be able to process physical signals, regardless of the area in which they were generated, all these signals can provide valuable information, in some crucial cases, that we need to know how to deal with. Students in scientific and technical degrees must receive an eminently practical and applied, experimental and scientific education, which helps to understand - in the deepest sense of the word - the abstract concepts learned in the theoretical classes, which also have a high mathematical load [8], [9], [10]. This experimentation does not always occur in the classroom due to overcrowding, lack of resources, lack of time, cost of instrumentation, etc. [11] Problem: Difficulties in the learning of the subject Digital Signal Processing in the Biomedical, Telecommunications and Electrical careers of the Faculty, due to the high degree of mathematical theoretical concepts that they require, which has caused lack of motivation in the students and low academic results.

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Research objective: Development of an interactive tutorial for the development of signal processing practices that incorporate elements of reality in subjects of various careers and at different levels, according to the students' preparation and the training objectives of each course. A multimedia system can be Khan Academy, a non-profit organization founded by Salman Khan with the mission of providing a world-class free education for all. The site offers more than 5,000 educational videos online in a series of subject areas (including mathematics, science, economics, finance, history and art), an extensive repository of mathematical exercises, data and information in real time regarding the advances and difficulties that users present when using resources. The Khan Academy platform provides resources for students and teachers. The four main components of the site that support learning are: videos, exercises, data, and a community of users. They all work together to create what Khan calls "a personalized, refined and interactive environment for learning." However, this site is not accesible from Cuba. In the Electrical Engineering Faculty of the UO in Santiago de Cuba there is no an educative software as didactic mediator that helps to improve the teaching learning process mainly in signal digital processing subject that allows students Access faster to the content of this subject, even to research, interact with demonstrative and interactive questions to fulfill a higher development of professional abilites being useful for both activities face to face and semi face to face for the improvement of knowledge of the students Taking into account the previous statement, the following was determined as a general objective: Implement a Virtual Learning Environment for the subject Digital Signal Processing (VLEPDS).

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Materials and Methods

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Design of the Virtual Environment PDS

The Virtual Learning Environment for the subject Digital Signal Processing has the following functionalities according to the different user roles. Student: They have access to all the information without privileges to modify it. This user covers the students of the Electrical Engineering Faculty, being those who interact more with the application, it is for whom the software was conceived.       

Request management Access to Questions Access to Videos Access to topics Access to the bibliography Access to the glossary of terms Access to statistics of learning

Teacher: This user is in charge of managing the resources that the software has, with the objective of keeping the content updated within it. It is the person trained in the

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subject matter, the teacher with permissions within the software to manage these resources.       

Management of topics Questions Management Video Management Management of bibliographies Terms glossary management Management of consultation materials Access to statistics of student learning

Administrator: You can insert, modify or delete the users of the system, as well as manage the resources of the subject    

Student management Teacher management Show list of students per career Show list of teachers

Next in figure 1 the navigation map of the VLEPDS is shown, relating the pages to which you will have access depending on the role.

Fig. 1. Navigation Map

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Tools and Languages

Django is an open source web development framework, written in Python, that respects the design pattern known as Model-View-Controller. The fundamental goal of Django is to facilitate the creation of complex websites. SQLITE It is a relational database management system, it is fast, reliable and easy to use, and it is multiplatform, multi-user. The Python language is compatible with SQLite, because of the extensive set of instructions defined for the treatment of it. Python is an interpreted programming language whose philosophy emphasizes a syntax that favors a readable code. It is a multi-paradigm programming language, since it supports object orientation, imperative programming and, to a lesser extent, functional programming. It is an interpreted language, it uses dynamic typing and it is multiplatform.

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2.3

Architecture of the Virtual Environment PDS

Django is known as an MTV Framework, see figure 2 M means "Model" (Model), the access layer to the database. This layer contains all the information about the data: how to access these data, how to validate them, what the behavior is, and the relationships between the data. T means "Template", the presentation layer. This layer contains the decisions related to the presentation: how some things are shown on a web page or another type of document. V stands for "View", the layer of business logic. This layer contains the logic that accesses the model and delegates it to the appropriate template: you can think of this as a bridge between the models and the templates

Fig. 2. MTV Architecture

2.4

Domain Model

The design of the database of the VLEDSP consists of 5 fundamental tables Student, Teacher, Videos, Exercises and Documents, which are related between them as a relation of much to much, with the objective of registering each activity that the students perform in the learning environment and on the other hand that the teacher has proof of them. As essential attributes in these new tables are the date and time, for the statistics and reports that must be obtained from the activity of each student in the VLEDS, see figure 3

6 Fig. 3. Entity Relationship Diagram

2.5

Observer Pattern

It is a design pattern that defines a dependence of the one-to-many type between objects, so that when one of the objects changes its state, it notifies this change to all the dependents. It is a behavioral pattern, that is, it is related to functioning algorithms and assignment of responsibilities to classes and objects see figure 4

Fig. 4. Pattern diagram of observer pattern

Subject: Know your observers, which can be from 0 to N, and offers the possibility of adding and eliminating observers. Observer: Defines the interface used to notify observers of the changes made in the Subject. Concrete Subject: Stores the state that is of interest to observers and sends a message to its observers when their status changes. Concrete Observer: Maintains a reference to a Concrete Subject. It stores the state of the Subject that is of interest to it and implements the Observer update interface to maintain consistency between the two states.

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Results and Discussion

The VLEDSP is a web platform to learn through videos, which the teacher proposes to his students, who have to see in their time of independent study to learn a new topic, see figure 5. In this way each student can go at their own rhythm, pausing the video or repeating the explanation as many times as necessary without interrupting others, it will also allow solving the exercises or problems that arise for each topic by selecting one of the possible answers, see figure 6.

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Fig. 5. Home page of the VLEDSP

As an interesting addition, the VLEDSP will allow each student to have statistics of their progress through their institutional email account, see the videos they have seen, the exercises they have completed, the areas they have not yet mastered and the points achieved.

Fig. 6. Videos page by topics

As a complement to learning and linked to their work practice, the VLEDSP has a link to the web application for biomedical signal management WebSA 2.0 [12], which includes four types of biomedical signals: cry signal, electroencephalogram signal (EEG), electrocardiogram signal (ECG) and electroculogram signal (EOG) Acknowledgements. Part of this research was made thanks to the financial support derived from the Webbasierte FuE-Plattform Zur Signalanalyse Project (WebSA) in colaboration with the University of Applied Sciences from Dusseldorf

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Conclusions

With the implementation of a Virtual Learning Environment with the Django tool for the subject of Digital Signal Processing, the management by the teacher of the contents of the same is achieved, as well as, a blended teaching medium for the students of each one of the careers of the Electrical Engineering Faculty that will allow to increase the level of independent study and the self-preparation in the students, not only through videos and documents but by means of questions that are presented as a

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means of checking the knowledge, supporting in great way to the teaching and learning process.

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