A Learning Resources Centre for simulation and remote experimentation in electronics Andrea Bagnasco

Paolo Buschiazzo

Domenico Ponta

Marina Scapolla

University of Genoa Via Opera Pia 11/a Genoa, Italy +390103532271

University of Genoa Via Opera Pia 11/a Genoa, Italy +390103532271

University of Genoa Via Opera Pia 11/a Genoa, Italy +390103532759

University of Genoa Via Opera Pia 11/a Genoa, Italy +390103532193

[email protected]

[email protected]

[email protected] [email protected]

ABSTRACT Laboratory activities are essential components of engineering education and professional practices. Nowadays, simulation-based laboratory and Internet-controlled remote laboratories are available in many educational institutions: this new scenario offers the potential for a deeper integration of practice with traditional lectures, and for a much wider and more efficient use of laboratories. Furthermore, it opens the road for the integration of laboratories into distance learning activities. In the paper, after a review of the current offer of both simulated and remote experiments, we present our approach to treat them as standard learning objects and to store them in a repository that has been developed on purpose. Last, we propose an integrated environment for an efficient exploitation of the experiments packaged as learning objects.

Categories and Subject Descriptors J.2 [Computer Applications]: Physical Sciences and Engineering – electronics, engineering.

General Terms Experimentation.

Keywords Virtual laboratory, remote laboratory, learning objects.

1. INTRODUCTION Laboratory activities are essential components of engineering education and professional practices. The evolution of electronic and computer technologies of the last decades has had a profound effect in organization and use of laboratories. As a result of the introduction of complex solid state components and the development of software simulation and design techniques, traditional hardware laboratories have lost their central place, being often advantageously replaced by software environments Permission make digital hard copies ofwork this for Permission totomake digital or or hard copies of alloforpart partorofall this work or personal or classroom usewithout is granted without that fee copies are personal or classroom use is granted fee provided provided that copies are made or distributed for profit not made or distributed for not profit or commercial advantage and or that commercial advantage copies on bear andcopy the copies bear this notice andand the that full citation thethis firstnotice page. To full citationoron the first to page. copy otherwise, to republish, otherwise, republish, post To on servers or to redistribute to lists, to post on servers, to redistribute requires prior specificorpermission and/ortoa lists, fee. requires prior specific permission and/or a fee. PETRA 2008, July 15-19,2008, Athens, Greece. PETRA'08, JulyACM 15-19, 2008, Athens, Greece. Copyright 2008 XXXXXXXXX…$5.00. Copyright 2008 ACM 978-1-60558-067-8... $5.00

where simulated components are used instead of real ones. Today, Electronic Design Automation (EDA) techniques are an essential part of the engineering design processes, while prototype fabrications are so complex to become out of reach from traditional laboratories. The evolution of electronic (especially digital) technologies, therefore, has suggested the replacement of the former experimental setup by a set of software tools, which constitute what we can call the simulation-based laboratory. The diffusion of the Internet has further accelerated the pace of innovation in electronics, somehow blurring the boundaries between local and distant applications. Current professional instrumentation is routinely provided with network connections and often managed through web interfaces. Nowadays, Internetcontrolled remote laboratories are available in many educational institutions: this new scenario offers the potential for a deeper integration of practice with traditional lectures, and for a much wider and more efficient use of laboratories. Furthermore, it opens the road for the integration of laboratories into distance learning activities. Internet-controlled educational remote laboratories for electronics are already available from many educational institutions. We use the term “virtual” to refer to the situations where the experiment hardware is either nonexistent or not physically accessible to the learner. This is the case of simulations, running locally or remotely, and of experiments that access distant real instrumentation. In the paper, after a review of the current status of virtual experiments, we present our approach to treat them as learning objects, which are stored in a repository, developed on purpose. As a final result we show how this approach may be conductive to a seamless integration of virtual experiments in learning environments.

2. VIRTUAL LABORATORY FOR EDUCATION IN ELECTRONICS Electronic engineering education is an almost ideal application field for virtual laboratories. The use of software tools is a regular practice in courses at all levels, following the steps of professional practices. Remotely operated real laboratories are becoming common in educational institutions, moving from the prototype phase to an effective deployment in the curricula. Such trend is not a surprise, since electronics, more than other engineering branches, has a strong familiarity with information and communication technologies. Another reason explaining the success of remote techniques in electronics is the fact that a good laboratory is not as expensive and difficult to set up as in other

technical fields. We could say that remote electronic laboratories are sort of inevitable and we can look at them just as the current implementation of previous educational strategies based on delocalised (at the learner’s home) assembling and testing of circuits such radio and TV sets. The advantages of remote laboratories are quite obvious when looking at them from the logistic and economic points of view. The option of replacing traditional laboratories with facilities available without time and space limitations with a very limited personnel cost is extremely attractive for universities. Nevertheless, attainment of the advantages quoted above is dependent on finding acceptable solutions to the problems presented by this new technology, both of technical and pedagogical nature [1,2]. Within the technical issues fall not only the necessities of developing the software environment controlling the lab but also the need of recreating as much as possible the features of the environment of a physically accessible lab. For example, manipulation of components and circuit assembling are, so far, out of reach for remote labs. Pedagogical challenges are, for example, the necessity of adapting traditional curricula to the new approach of lab work, of providing a tutorial support to the distant learners, to recreate the collaborative environment typical of the lab sessions conducted in presence. It is clear that remote labs do not replicate the same experience as a traditional lab and do not develop exactly the same skills. It will be useful, at this point, to present a few cases of implementations of software simulation and remote experimentation.

2.1 Simulation in electronics: a review In electronics, software simulation techniques are highly developed and extensively used both in the professional and educational domains. Existing implementations of virtual laboratories for digital electronics are based either on professional applications or simulation tools designed for educational purposes. Among commercial products specifically developed for the educational field we could quote OrCAD (see http://www.cadence.com/products/orcad), NIMultiSim (formerly Electronics Workbench) (see http://www.ni.com/academic/multisim), Tina Design Suite (see http://www.designsoftware.com), Digital Works (see http://www.spsu.edu/cs/faculty/bbrown/circuits/howto.html), MacroSim (see http://www.engineeringsoftware.com/pr/addProd106.htm), and Proteus (see http://www.labcenter.co.uk/index_uk.htm). A special category of professional simulators widely used in education is composed by developments suites for Programmable Logic Devices, such as Xilinx (see http://www.xilinx.com) and Altera (see http://www.altera.com). Their diffusion as educational tools is motivated mainly by the fact that the components’ manufacturers make them available for educational institutions at very favourable conditions. The scenario is more difficult to describe when dealing with simulators developed in a nonprofits perspective and generally available at no charge. A list of names and links is available in

[3]. It must be noted that, while the commercial packages tend to cover the whole set of digital devices and techniques, these tools are often limited to specific topics. It is somewhat risky to adopt one of them, since there is no guarantee that the software will be maintained. This is one the reasons that have convinced us to develop our own simulator, called Deeds. Deeds (see http://www.esng.dibe.unige.it/netpro/Deeds/Downloads.htm) is a learning environment for digital electronics that provides an innovative set of tools and resources for teachers and students. It is extensively used by the students of the first and second year of electronic and information engineering and as a support for project-bases courses. Deeds is composed of three simulators that cover combinational and sequential logic networks, finite state machine design, microcomputer interfacing and programming at assembly level. They are characterised by a “learning-by-doing” approach, and, being fully integrated together, they allow design and simulation of complex networks including standard logic, state machines and microcomputers.

2.2 Remote laboratories for electronics While virtual labs based on simulation are an established tradition in electronics, remote labs have a much shorter history. Nevertheless, just a few years after the first prototypes were introduced, they are carving their own place in universities with increasingly rich and sophisticated environments. As it was mentioned before, the electronic remote lab cannot be an exact replica of the traditional lab, being able to do, at the same time, less or more, accordingly to the point of view. The particular way the developers address the intrinsic differences between local and remote experiments generates different technical and pedagogical approaches. For example, remote labs can provide course management functionality, combining remote experiments with traditional lectures and offering a flexible environment that encourages the evolution from traditional teaching to active learning. This is the approach followed by Gillet [4,5] at Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland, focusing on the implementation of collaborative activities among students and teachers. McGinnity [6] of the University of Ulster presents another collaborative remote experimentation environment that allows students in disparate locations to simultaneously and collaboratively complete complex experimental exercises. His work is based on several client-server paradigms that facilitate single user remote access, collaborative working and lecturer led approaches to the provision of remote experimentation facilities. The remote control of instrumentation is not enough to set up a remote laboratory. Several pedagogical, technical, and structural issues must be faced to obtain modular and scalable systems. ISILAB [7,8] (see http://isilab.dibe.unige.it ), developed at the University of Genoa, has directed its efforts toward proper architectures and tools for an easy management of the system and a better pedagogical effectiveness. The approach, used in describing the components of online experiments, facilitates the upgrade of the laboratory and the sharing of experiments, defined as standard learning objects. One of the major drawbacks of remote labs is their inability to provide the same realistic experience typical of local labs, where students interface directly with devices, processes and instrumentation. In electronics, the instrumentation equipping

traditional laboratories for basic courses is almost standard. Nowadays most bench instruments are equipped with interfaces supporting remote operations, sometimes with the format of websites. Gustavsson at the Blekinge Institute of Technology, Sweden [9] has concentrated his efforts in maintaining as much as possible the environment of the classical electronic laboratory, recreating at distance the experience of building a circuit out of separate components in a solder less breadboard. His laboratory is equipped with an interface enabling students to recognize on their computers the instruments and the breadboard they have already used in the local laboratory. A sophisticated system of switches replaces manual assembling on the breadboard. Other ways to circumvent the problem of circuit assembling are represented by board-based laboratories, such as ISILab, where the experimenter can switch among several pre-built circuits and eLab [10]. The laboratories based on Programmable Logic Devices (PLD) represent a valid approach to design and test digital systems. A PLD is configured as the circuit designed by the experimenter, by downloading a file in its memory, and successively tested with remote instruments. [11] In synthesis, the current state of the art of remote laboratories in electronics presents a fragmented picture where individual laboratories are self-standing isolated elements. Standard experiments, such as the ones for basic analogue and digital circuits, are offered by a large numbers of laboratories, with different modalities for access and execution. A few laboratories offer, in addition to experiment, course management tools, providing an extra service to their users but, at the same time, duplicating functions that are more efficiently performed by Learning Management Systems. (LMS).

3. SIMULATION AND REMOTE EXPERIMENTS AS LEARNING OBJECTS 3.1 Learning Management Systems and Learning Objects Nowadays, LMSs are extensively and successively used by educational institutions for a variety of situations, from support to traditional lecture-based courses to e-learning and distance learning. LMSs consist of a set of software tools, generally webbased, designed to manage users, roles, courses, instructors and facilities in education. Given the trend, which is quite common, to see experiments not as isolated events but as an integral part of a course, the integration of virtual experiments with the other resources provided by LMSs becomes a natural step. In this context a virtual experiment takes advantages of several pedagogical features, such as identification and profiling, discussion forums, testing, report preparation and delivery, user statistics and feedback. The wide offer of LMSs both as commercial products and open source software packages has brought into the foreground the search for standard methods to organize, classify and share the learning materials. Nowadays, we use the term “learning object” (LO) to define any digital resource that supports learning. LOs identify a way to organize learning contents: usually small units, as much as possible independent and self-contained, reusable in different contexts for different purposes and, last but not least, tagged with metadata for an easy classification and search.

The LOM (Learning Object Metadata), established by IEEE, is the current standard [12] in the field of metadata. It allows describing and classifying learning objects independently of their format and educational field. The SCORM (Sharable Content Object Reference Model) model [13] extends the LOM standard by further specifying the run-time environment, including APIs and data elements needed to run the SCOs (Sharable Content Object). Nowadays the SCORM is widely adopted to package and deliver learning objects and many commercial and open source LMSs are conformant to this standard. A course can therefore be composed by a set of SCOs providing lectures, syllabuses, exercises, tests, etc. SCOs can be constructed using any digital format for text, pictures, audio, video etc. The format information contained in the metadata allows a straightforward opening and fruition of the material.

3.2 Virtual experiments as learning objects An important part of technical and engineering courses, laboratory practice, is not yet managed using the standard learning object approach. In principle, metadata can be applied to laboratory experiments, to classify them according to their specific characteristics and allow a course designer to decide which ones to include in a course. In practice, when one comes down to the exploitation of virtual experiments, because of the particular nature of the material, several problems arise. Simulation-based virtual experiments, using a locally installed application to run the experiment, do not ask for specific requirements. They can be assimilated to generic learning objects in term of easiness of exploitation. Instead, if the simulator necessary to run the experiment is installed on a remote server, the situation is similar to the experiments that access distant real instrumentation, as we describe in the following paragraph. These experiments require the availability, somewhere and sometimes, of an Internet- connected hardware system performing the measurements or simulating it. The LOM metadata set is not enough to provide all the information necessary to run the remote experiments. The research community has investigated the problem and proposed solutions. The pioneering work by the PROLEARN network has laid the foundation for creating a catalog of online experiments, using an extension of the metadata for describing them [14]. The metadata that we propose to classify remote experiments are listed in Table 1. Table 1. The metadata to classify remote experiments Period

StartDate

Indicates the availability period. If this metadata is not present, the experiment is always available for the this LMS Indicates when the availability period starts.

EndDate

Indicates when the availability period ends

Start Time End Time Day

Define the period of availability (times are GMT) Indicates the days of the week, when the experiment is available. If this element is not present, the experiment is available for the whole week. ftp, e-mail, web page, synchronously

Results Access mode

Reservation

Online reservation, Offline reservation, Stand in queue, Direct access

3.3 A repository of learning resources for electronics Classification of learning material is, of course, functional and preliminary to its exploitation and sharing. Next logical step is therefore the establishment of an online repository where exploitation and sharing take place. This paper reports on the set up of the Virtual Reality Learning Resource Centre (the VR-LRC available at http://vr-lrc.dibe.unige.it ) by a group of educational institutions supported by EU funds. The VR-LRC collects material in the specific domain of electrical engineering and includes, together with VR resources, traditional learning material. All the learning objects are SCOs and classified by using a proper subset of the LOM fields listed in Table 2. If the LOs are remote experiments the metadata extension of Table 1 is applied. Table 2. The subset of LOM metadata to classify remote experiments General:

Rights

Identifier, Catalog Entry, Title, Language, Description, Keyword Contribute (Role, Entity, Date), MetaMetadata (Identifier, Catalog Entry, Contribute (Role, Entity, Date)) Other Platform Requirements, Educational Learning Resource Type, Typical Learning Time Copyright and Other Restrictions Description

Classification

Purpose, Description

Life Cycle

Technical.

The repository is based on the open source Content Management System (CMS) Plone [15] and can be managed by a web interface. The basic functionalities of the VR-LRC are to store learning resources, to browse among them, to search specific resources using metadata (see Figure 1). Guest users can browse the repository, see the learning object metadata and download objects whose access is not restricted. Registered users have access to all the functionality and are the ones who are in charge to fill the repository. Their contributed material is saved with a reference to their institutions. Packages for SCO creation and metadata definition are available; in spite of that, for a content developer, the creation of a SCO might be an unfamiliar task. In addition, the available tools do not support the metadata specific for remote experiments. To overcome this problem and to encourage the use of the VR-LRC, a standalone Java application, the “SCO Editor”, has been developed by us. Users can download it directly from the VRLRC site and use it freely.

4. THE INTEGRATED LEARNING ENVIRONMENT Figure 2 sketches the learning environment that takes full advantage of the repository of SCOs, including virtual experiments. Such environment is based on independent subsystems, which provide their specific functionalities and move towards seamless negotiation, consumption and orchestration of services. The relevant subsystems are the LMS, the VR-LRC and the remote Laboratories (Lab). The LMS can be any available SCORM compliant product.

Figure 1: The VR-LRC search page The VR-LRC is the repository of learning objects previously described. The figure shows that each SCO contains resources and a manifest based on standard LOM and some extensions specific to remote experiments. These extensions, which allow defining the access policy to the resource, are the ones detailed in Table 1. The Lab subsystems in the figure represent the remote laboratory servers that execute the experiments. Different Labs can be integrated in the learning environment. The Labs can exchange information with the LMS via the SCO object; the information can travel both ways. The SCO receives information on the user (identification, level, course…) from the LMS and instructs the Lab to tailor the experiment for that specific user. Let’s suppose, as an example, to use the same experiment set-up for students

belonging to different courses. On the basis of the information exchanged between the LMS and the SCO by the SCORM API, the text describing the experiment and the proposed activity can be changed and adapted to the student level. Because of the wide variety of remote Labs implementations, many still at the prototype phase, it is not yet possible to define a standard interface between SCOs and Labs. Therefore, at this level of system description, the Labs should be seen as black boxes, both under hardware and software points of view. The SCO that controls a specific experiment is written according to the specifications of the remote Lab it interacts with.

VR-LRC LMS

Course xxx

Info about Users and their activities,

SCO SCO SCO

SCO Resources LOM Metadata

1. I need the learning resource ‘Exp1’

3. Exchange of info (SCORM Data Model) (i.e. username and LMS URL)

Usage Policy

2. Here it is the SCO

Browser Course page opened in the browser

SCORM API

4. I’m ‘XY’, from ‘url…’. I would like to run this experiment

SCO: Lab

Index.html Redirect to http://www.remlab.org/exp1.html

5. Ok, come on / No, it is forbidden

Figure 2: The flow of information among the components of the learning environment

In addition to presenting its three main blocks, Figure 2 provides a sketch of the system operations. The flow of information can be logically divided in two phases: the interaction between the LMS and the VR-LRC at the time of course creation and the exchange of information taking place when a learner runs an experiment. The VR-LRC is the natural container of all the learning material, from which the course designer downloads into the LMS the objects needed for the course. The modalities for the search, identification and downloading of the SCO from the VR-LRC to the LMS may range from a simple link to the VR-LRC, to more sophisticated procedures that see the VR-LRC as service or content provider. At this point, we assume that the teacher has created a course containing remote experiments. When the student asks to run one of them, a dialog takes place among the LMS, the browser in the learner workstation and the Lab. Figure 2 shows that a request is passed from the client browser to the LMS (step 1). The SCO is returned (step 2) and executed on the student workstation. Thanks to the SCORM API, the SCO can exchange information with the LMS (step 3). In the case described in the figure the SCO asks the user account and the URL of the LMS hosting the course. Such information is essential to implement an access policy on the Lab (steps 4 and 5).

The cooperation among LMS, SCO and Lab allows the management of on-line experiments as components of a learning path. The tutorials, which often complement the lab practice, can be separate learning objects and can be tailored on the students’ skills. The same experiment can be used in different contexts and with diverse educational objectives. For example, students can be requested to review the theoretical foundation of an experiment before executing it. Then the system can evaluate the acquired theoretical knowledge using a quiz session before granting the access to the further steps. Passing this preliminary phase allows students to execute the experiment.

5. CONCLUSIONS The conception and diffusion of a learning resource centre for VR based material is an important step to support the community of developers and users of VR material and to increase its visibility. Cooperation and internationalization, as well as exchange of ideas and experiences, are enhanced. An integrated, compliant and expandable VR-LRC favours a stronger interconnection among European universities and may create closer links between universities and industrial enterprises. A wide collection of VR material could help promoting a process of standardization in the field of remote labs, by providing to the developers an up-to-date and realistic picture of the state of the art in the field. In the current phase of development it is not yet possible to report on the

effectiveness of the learning environment in terms of reduction of costs and time, and increase of pedagogical usefulness. Feedback by users is being collected.

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