2010 International Conference on Signal Acquisition and Processing
DSP course teaching using Moodle V. B. Dharmadhikari1
D.Y.Loni2
1
2
Department of Electronics, Faculty of Electronics, Walchand College of Engineering, Sangli, India
[email protected]
Department of Electronics, Faculty of Electronics, D.K.T.E Textile & Engineering Institute, Ichalkaranji, India
[email protected]
Abstract--Advances in the multimedia technology provide an opportunity to enhance learning an Engineering subject like Digital Signal Processing (DSP). The paper presents a new teaching method that effectively integrates Information Technology into teaching - learning process. The entire DSP modules are implemented in an open source Course Management System (CMS), Moodle. It helps the students at undergraduate level in learning introductory DSP and experimenting with its basic concepts. At the same time, course instructors also find smooth flow of the contents covered that helps them in enhancing the effectiveness of their lectures, assign tasks to students with simple methods of evaluation and easy tracking of student’s progress at every stage of learning.
an initiation for the development of this E-learning tool. This tool provides the learners with extra flexibility, better class interaction, attractive teaching material, learning continuity, resource standardization and full time alternative support and hence helps to increase learner engagement. It is thus a huge task to simplify the concepts of such a mathematical subject using an E-Learning approach. Also the proper choice of E-Learning tool plays a crucial role. Effective E-Learning requires through knowledge of the subject and skills to present the contents methodically.
Moodle has been adopted by many people and organizations around the world, as it offers a tightly integrated set of tools to develop a powerful E-Learning tool. The focus here is upon effective adoption of the tool so that the teacher concentrates more on the learning activities and uses all the Moodle tools successfully. Moodle helps to present the course contents exactly the way the teacher has mapped the subject structure, but through a more controlled environment. The method is well suited for teaching the theoretical and mathematical concepts of DSP.
Web-based course is the main approach to carry out teaching activities of E-Learning. Well-designed E-Learning provides best learning environment. However, the current status of developing web-based E-Learning courses is not optimistic. The major problem is that, most of persons who develop web-based E-Learning courses are members of computer profession, but teachers who truly understand characters of students, subject and teaching regulations of ELearning have serious difficulty in developing web-based courses. So effective teaching cannot be realized. On a long view, low quality web-based E-Learning courses not only waste time, money and human resource of developers, but also lead the result that students gain little and teachers loose interest. Hence a proper choice of E-learning tool is most essential when building such a web-course. An E-Learning course should be such that it supports editing teaching contents according to instructional strategies, which is in accordance with characters of students and subject. In the current E-Learning landscape, the most prevalent architecture used to deliver content to a learner is via a course management system. Moodle is the most popular CMS for online learning these days [6]-[7]. Educators use Moodle to develop and support online education. Moodle allows to easily set up interactive online classes without having to learn HTML or create individual web pages. Also allows easy uploading of syllabi, host discussions, accept assignments electronically, send and receive course specific email, give quizzes online and many more. Thus, Moodle allow teachers to focus more in the learning activities rather than on the software itself. The implementation of DSP modules in Moodle results in a powerful E-Learning tool.
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Keywords-animation; assignment; engineering education; multimedia; question bank; quiz; video.
I.
INTRODUCTION
Teaching a large mass is always a very challenging task for Educators. This is due to many difficulties imposed on the teaching-learning process. These difficulties vary from encouraging attendance, delivering well-balanced course content to keep students’ interest in the subject, getting students actively participate in the learning process, and motivating students. With the rapid development in Information Technology, especially the Internet, it is possible to address the above difficulties with the help of various existing technologies. The proper use of Information Technology not only enhances the students learning experience but also maximizes student productivity [5]. DSP is traditionally a highly mathematical subject. To learn various DSP concepts, large numbers of mathematical equations are introduced to students at the initial stage. However, many students just want a simple introduction to the basic concepts and techniques of DSP. Also the wide spectrum of students makes it very difficult for Educator to deliver well-balanced course contents to keep the attention and interest of most of students [1]-[2]. This complexity is 978-0-7695-3960-7/10 $26.00 © 2010 IEEE DOI 10.1109/ICSAP.2010.11
USING MOODLE FOR E-LEARNING
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MOODLE COURSE BUILDING
Building a course for a subject like ‘Digital Signal Processing’ is not merely a technical matter. First a full mind map for the subject is drawn taking into consideration the mind set of the student in all phases of the design and implementation. This map is initially made by referring the curriculum. The focus is upon areas that students generally find difficult to grasp, and are key concepts. The next task then is to explore the layout of Moodle to best suit the course content and its effective delivery.
Understanding the differences between analog and discrete spectra are one of the reasons that DSP has the reputation for being difficult to learn. Hence this module plays a very significant role. It explains the relation of frequency in analog domain to its equivalent digital representation. 4) The Convolution module Convolution is a fundamental operation in DSP. With the explanation of LTI system and its impulse response, the students are comfortably introduced to convolution. The module describes properties of convolution, methods of convolution, like; graphical, matrix and polynomial. The students are also introduced to frequency domain convolution .i.e. convolution theorem. Role of convolution theorem in digital filtering is then touched upon. For better understanding the entire module is assisted with videos explaining the same in an animated fashion. 5) The Discrete Fourier Transform(DFT) module One of the Fourier analysis tool is the discrete Fourier transform, more popularly known as DFT. But instead of starting with DFT directly, the module discusses all of the Fourier analysis tools, i.e. Fourier series, Fourier Transform, Discrete Time Fourier Transform and then introduces DFT. The module makes the student realize the significance of DFT in the field of DSP, also guides on how to correlate the DFT samples with its frequency, explains why is DFT spectrum symmetric, taking an example proves the periodic nature of DFT. The module also describes the time domain aliasing effect. The animated videos included make the module enjoyable. 6) Basics of Digital filters Digital filters are a very important part of DSP. This module begins with definition of filter, filters specifications and describes how LTI system works as a digital filter. The aim is to touch upon the background required to understand the digital filter classification. 7) Finite Impulse Response (FIR) filters This module begins with describing the characteristics of the FIR filter, its transfer function and the specifications needed for its design. The two FIR design methods .i.e. Fourier series and Windowing methods are detailed. The module mainly focuses upon the principle behind FIR technique .i.e. necessity of truncating the impulse response coefficients, which, the students should clearly understand. The corresponding effect that pops up due to sudden truncation, i.e. the Gibbs phenomenon is also touched upon. 8) Infinite Impulse Response (IIR) filters As IIR filters have a close approximation with the analog filter, the module includes the discussion on the basic technique of IIR filter design that transforms wellknown analog filters into digital filters. The two IIR design methods namely, Impulse Invariant and Bilinear Transformation methods are detailed. The module includes mathematical derivation of all the equations required to analyze the IIR filter and also details on s-plane to z-plane mapping.
A. Mapping the structure of the subject Fig. 1 shows the structure of the subject designed at the initial stage of e-tool development.
Figure 1. Map of the subject structure
In the center is the title of the subject. Radiating from the center are topics, and for each topic a number issues or subtopics are shown. Each subpoint is illustrated with the support of text, along with video demonstrations, Matlab programs to justify the concept and a set of question bank at the end that assists the students to check out their understanding. B. The DSP modules included in the tool DSP is a highly mathematical subject, and the standard DSP textbooks contain a lot of mathematical exposition. This is necessary for a profound understanding of the subject. Students need to put some efforts to appreciate the underlying concept. It is this initial complexity and apparent abstractness that keeps students away from learning actively. Taking this as a challenge the tool includes following eight modules systematically laid, that helps the students to penetrate the entry barrier and speedup the learning process. 1) Testing the background This module is presented in the form of a Quiz. Many DSP concepts require a deeper background of signals and systems theory. The quiz consists of basic questions that check the fundamentals of the student. The purpose of this module is to make the student realize his/her stand before attempting with the main contents of DSP. 2) Introduction to DSP This module introduces the student to DSP. It includes concept of signal and its types, signal processing, why use digital domain?, comparison of Digital and Analog signal processing. Thus developing the curiosity in the subject, the module ends with discussing few applications of DSP. 3) Concept of discrete frequency
C. Moodle implementation
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Course development means creating and uploading educational content and organizing its activities. But simply putting the course materials and activities on-line just for the sake of having a web course is unlikely to produce good results. This is where a teacher has to be called upon to devise methods and materials to finally come up with an ELearning tool that directs learners to systematic approach of the course study. As a teacher the course is well planned from a pedagogical viewpoint with clear aims and well-defined approaches. The course design is explained in following steps. 1) Step1:Moodle course setting Moodle course starts with an empty course environment made by the administrator. The first activity to undertake is to customize the course settings. These settings determine the look of the course and its accessibility. It is therefore important to get the settings right. 2) StepI1:Adding content to Moodle To each week Activities and Resources are added for the students. The lesson tool of Moodle is adopted to create interactive study material. The Lessons feature allows teachers to create an activity that is best, compared from the perspective of the student. The Moodle HTML editor tool makes it quite powerful in content creation and also makes the lesson's content interesting. The course content is distributed in total into 45 lessons. Along with this, every week is supplemented with additional resources other then the lessons that help the students to better understand the concepts. Resources are the part of the course. These resources provide the students with the additional information of the topic covered in that week. Moodle allows for the integration of a wide range of resources. These include any kind of text-based or htmlformatted documents, multimedia resources such as graphics; video or audio, PowerPoint, PDF files, and even Matlab programs. 3) StepII1:Building lesson The actual contents of DSP are now stuffed part by part in the Moodle lessons. Each page in the lesson has a question at the bottom. The student reads the contents on the page and answers to the questions that follow. The questions are so designed that makes the student to think and correctly apply his understanding from the lesson content he just went through. If the answer is correct, the student will get that feedback and move to the next part, if the answer is incorrect the student will get feedback about his incorrect answer and return to the initial text, or to a page with extra information about the subject to try again. Thus it is the teacher who decides upon the lesson structure and how to best use its flexibility to achieve the educational goals of the course. Thus the students focus on the information in the lesson. 4) StepIV:Lesson grading A lesson can be assigned grades. The students earn the grades by answering the questions that follow the lesson. For a graded lesson, the system computes the number of right and wrong answers to compute a grade. The grading
system motivates the students to study the material. It also contributes to retention of the student in the learning material of the course. In the e-tool, each lesson is graded out of ten. A score is assigned for each answer. The score is set to 0 for a wrong answer and 1 for a correct answer. The overall score is computed when the lesson is completed by the student. IV.
MOODLE COURSE TEACHING
With the DSP contents stuffed into Moodle, here is an outline on how to proceed with the course teaching. Once the students are enrolled into the course, they can begin to Moodle with course contents. The course settings are so set that students can view only a week portion at a time. This is the advantage that Moodle presents. The students are exposed to those contents that the teacher has well planned of. This controlled course structure of Moodle helps in presenting the contents to the students as per the mind map of the subject prepared by the teacher. Thus at the beginning the students are exposed to contents of the first week. The week1 content of the course is shown in Fig. 2.
Figure 2. Week1 structure of the course contents in Moodle.
The week1 covers the first module .i.e. testing the background. This module is presented to the students in the form of a quiz. Many DSP concepts require a deeper background of signals and systems theory. But normally it is observed that only about 10% of students meet the minimum required level of curriculum knowledge. Therefore, in order to engage the other 90% of students, the educator will have to cover some of the pre-requisites before starting with DSP. Therefore the purpose of this module is
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to make the student revise back some concepts. The students attempt the quiz and the scores are automatically recorded in the grade book of Moodle. The week also includes some resource files that discuss the basics of signals and system. In the same week the students are also made to go through the basics of Matlab. Matlab is introduced to them right from the scratch through the special videos. Students can watch the videos any number of times throughout the week. Also each week includes tasks for the students to work on, presented to them in the form of assignments. Students have to submit the assignments to the teacher within the same week. These assignments include questions based on the portion covered in that week. Thus week1 is aimed at recalling the basics and introducing the students to Matlab. From second week students slowly move towards the core of DSP. The week2 content of the course is shown in Fig 3. Week2 covers the second module i.e. Introduction to DSP. The students go through the lessons like introduction to signals, system, signal processing, comparison of Digital and Analog signal processing and applications of DSP. Every lesson has set of questions that student answers and the score of which is maintained in the grade book of Moodle. Following at the weekend are the assignments. The assignment evaluation informs the teacher about the understanding and involvement of the student in the course study.
Multimedia is the original rapid technology for supporting learning. Sound, music, visuals, movement and talking encourages the user to participate in the learning process. A. Animated videos: The E-Learning tool includes number of videos that follow the textual explanation in the lesson. These animations and accompanying audio not only adds the extra stimulating flavor to the class, but also assured accurate and complete delivery of the important messages every time, all the time. Students remain completely focused and attentive throughout the time when the animated videos are being played. Moodle provides the provision to include links to these videos in the lesson. An example from the e-tool is shown in Fig. 4. After going through the lesson the student can click on the link, which pops up the video. Even though the concept is detailed in the lesson, the video explaining the same in an animated fashion creates a complete different impact on the student's mind. These animated videos are always the best medium to recall as compared to text.
Figure 4. A sample lesson from e-tool. Figure 3. Week2 structure of the course contents in Moodle.
Accordingly, the students are exposed to the DSP contents sequentially week after week as planned by the teacher. Thus, taking into account average time the student may require to go through and understand the concept, the complexity of the concepts and the task the students are directed to perform, decide the week structure. Thus the weekly structure outline shows simple lessons that basically start with the DSP concept and goes into its depth in a straight line path, one lesson after the other. As a result, a simple maze is created in which a student studies the initial text/sound/video piece embedded in the lesson and then is presented with set of questions to test his understanding of the text. The assignment submission keeps the students on their toes and requires their thorough involvement and study. V.
Figure 5. A sample video from e-tool.
MULTIMEDIA DEMONSTRATIONS.
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The glimpse of the sample video that opens is shown in Fig. 5. The videos in the e-tool were developed using SnagIt screen capture software. SnagIt is a screen capture tool that operates under the Windows operating system. It is the only screen capture software that captures images, text, and video from the Windows desktop. B .Matlab videos: The E-Learning tool includes a suite of exploratory demonstrations programmed in Matlab, designed to motivate and inspire learning [3]-[4]. The tool includes Matlab programs on modules like convolution, DFT and digital filters. These Matlab programs are rightly placed in the tool, following or matching the theoretical discussion. Looking at the extensive support that Matlab extends to effectively justify the DSP concepts, Matlab is introduced to the student right from its introduction. Instead of textual explanation, the best way adopted for this implementation is by developing Matlab videos. Following Matlab videos are included: • Starting with Matlab • Graphics using Matlab • Creating, saving and executing script file • Using built-in functions and on-line help
Figure 6. A sample lesson report in Moodle.
C. Assignment module The third Moodle tool used for the student evaluation is the assignment module. The assignment feature enables the teacher to assess student progress on a one-to-one basis. Every week of the course has two assignments, one is offline and the other is online as supported by Moodle. The assignment includes essay questions, numerical and Matlab programs that cover the lesson content for that particular week. Students have to thoroughly go through the lessons and then attempt the assignment.
VI. USING MOODLE ASSESSMENT TOOLS FOR STUDENT EVALUATION Moodle includes an assessment system that helps teachers track student progress. It details on how often the student goes through the course, and which specific section and options within the course he uses on a given visit. This information is stored locally within the Moodle database, and can be freely accessed by a course teacher at any time. Following are the Moodle assessment tools used in the course.
VII.
STUDENT TRACKING
Moodle helps to keep track of every student's activity on the site, and records all their scores. It records student login data and also tracks the user rates. This Moodle tracking feature is used to know about the student progress in the course. If a student doesn't spend time with the material, he will have difficulty in succeeding the course. Frequently, students who don't do well simply haven't spent the time working with the material. The teacher can analyze the course reports on a regular basis, to monitor when the students engage with the course material. These reports also inform the teacher which resources and activities students find most valuable.
A. Lesson reports The entire DSP course content is presented to the students in the form of a lesson activity of Moodle. Naturally, the learning effect of the lesson stands or falls with the quality of the questions asked. Lesson report plays an important role for such analysis. A sample lesson report is shown in Fig 6. It informs the teacher what percentage of the class selected each answer on a question page. This gives an idea about the entire class approach in understanding the lesson. The teacher can further correctly identify the critical spots in the lesson where the students are making a likely mistake and are misinterpreting.
VIII.
CONCLUSION
A new teaching approach is presented for effective teaching of subject like Digital Signal Processing. The tool incorporates method to address the difficulties faced by students in learning an Engineering course. Use of Matlab ensures that students understand the underlying concepts, the animated videos helps in easy recalling and the questionnaire keeps learner attentive. Thus by improving efficiency of classroom teaching and offering a new method of teaching-learning for a mathematical subject like DSP, reduces the effects of diversity at curriculum level and
B. Quiz module The DSP course incorporates the quiz module of Moodle in Week1 of the course structure. This tool includes grading functionality. The quiz result details the teacher on how the quiz was attempted, displaying the correct/incorrect answers and the individual score of each question in the quiz. It even informs about the time taken by the student to complete the attempt along with the date when the quiz was taken on.
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improves individual's interest in the subject. Therefore ideal classroom experience should be amalgamated with ELearning so that everyone will be prepared for full participation and no one slows down the rest of the class. Further by integrating the course contents in Moodle, enables a teacher to assess and track each of the student's progress. This is simply not possible in a traditional classroom environment constrained by time and space. Some students are likely to be left behind. Not so in Moodle. And this is the essence of a well structured course. This new teaching approach is definitely enjoyable and productive. REFERENCES [1]
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