Interactive Hands-On Tools as Learning Objects on Web Services

Tarmo Robal, Ahto Kalja Tallinn University of Technology, Raja 15, 12618 Tallinn, Estonia

tarmo@pld.ttu.ee, ahto@cs.ioc.ee

Abstract

This paper introduces a framework for using web

services as the platform for creating web-based learning objects, delivering features such as modularity, interoperability and extensibility for interactive tools in the field of digital microelectronics. 1. Introduction

Today we are living the era, where electronics and computer systems are an integral part of our lives. Devices equipped with microelectronics can be found everywhere. Microelectronic systems have grown large and sophisticated, yet they are composed of basic logic gates. The rapid development and shift to mass-usage of electronics has introduced a dependency on such devices and vulnerability in case of system failures. This has also raised the need for engineers educated at universities around the world to have good skills.

With the evolution of the Internet, different virtual learning environments (VLE) have become available providing users access to course content everywhere and any time where a network is present. Still, VLEs are mainly autonomous and lack application-to-application communication and interoperability. The content is mainly static with some interactive stand-alone tools (e.g. Java applets). Though, the Internet today is by far more than a mean for providing downloads of materials or static HTML-pages – thus we need to choose the Internet as the platform of our applications and move on to Web 2.0 era, with dynamic view and interactive applications brought to user in browser window, and take advantage of web services - one of the core components of Web 2.0.

A Web service (WS) is a self-describing, self-contained software module available via network, such as the Internet, which completes tasks, solves problems, or conducts transactions on behalf of user or application [1]. Being independent of platform and programming language used, it has become a powerful

way to put unalike applications on different platforms to communicate easily with each other in machine-to-machine interaction over a network.

Many standards and standardized approaches have been developed to achieve this. The World Wide Web Consortium proposes to use SOAP (Simple Object Access Protocol), UDDI (Universal Description, Discovery and Integration), and WSDL (WS Description Language) for web services. As the XML-based SOAP is considered too heavy, additional alternatives have been developed. One of the most widespread is JSON (JavaScript Object Notation) [2], a lightweight, human-readable data-interchange format easy for machines to parse and generate. Other alternatives include GData (Google Data API), XML-RPC and REST (Representational State Transfer). Most implementations of web services use Hypertext Transfer Protocol (HTTP(S)) as the transport layer.

Bringing WS’s to e-learning would enable to compose courses from learning objects distributed all over the Web and ease the burden of managing the variety of different learning environments, enabling them to work together using features and tools already available in some environment, leading to a higher level of content exchange and interoperability.

A number of studies have been carried out proposing to use WS’s for interoperable learning object repositories [3], web portals [4], combining learning content of available resources [5]-[7] or assembling an e-learning system from a set of web services [8]. In [9] ways of building VLEs around WS’s has been explored based on the popular Moodle environment. Well-known and widely used VLEs Blackboard (WebCT) and Moodle have implementations of web services allowing to connect them from outer applications for information retrieval but lack of services for the vice versa action. Thus, WS are still not widely used in common VLEs and there is no support for them in an easily accessible way not only for IT experts but also for teaching staff. There seems to be no approaches oriented on developing interactive learning objects based on web services.

73978-1-4244-4406-9/09/$25.00 ©2009 IEE

Our previous research comprises of developing a lightweight VLE called e-EDU [10]-[12], used at the Tallinn University of Technology for information and communication technology studies. The framework described herein provides a logical continuation to our previous research enabling development of web-based interactive learning objects that are not only usable as stand-alone applications, or in particular environments, but could be integrated over the Internet and improve education of next generation engineers.

The rest of this paper is organized as follows: in Section 2 an overview of the framework is given. In Section 3 we discuss the applicability of the framework coupled with an example service and tool, and Section 4 outlines the conclusions.

2. Creating learning objects with WS

The e-EDU Web Services Initiative (WSI) [13] provides a framework for developing interactive learning objects (i.e., educational tools) based on web services. A learning object (LO), as defined by the IEEE, is "any entity, digital or non-digital that may be used for learning, education or training" [14]. The framework targets the following advantages while developing LOs: (a) single implementation of complex algorithms/systems and their multiple reuse through different clients; (b) independency of VLE platform; (c) development of interactive tools without excessive programming and costs for courses in different VLEs; (d) apply distributed computing and free client machines from heavy data processing. These goals are achievable by using common web service standards or their alternative technologies.

The advantages of using WS for developing LOs lie in the following. Firstly, the modularity property enables to build up complex services from atomic ones, and add or replace services with ease even in the running system. Secondly, as services are defined by standard specifications and communication is via standard protocols (e.g. HTTP), interoperability is achieved. The two latter together provide extensibility, as the third property. Fourthly, services and clients can be implemented in different languages and run on different platforms (e.g. Java, .NET, PHP). Fifthly, lower development costs as applications can be integrated faster and easily. Sixthly, there is no need to architecturally modify existing systems, only a service interface is needed for interaction. Finally, services can be logically and physically distributed, with functionality brought together via consuming the services over the Internet.

Nevertheless, there are disadvantages to consider. Interruptions in network connections occur from time

to time leading to poor availability of services as the communication link between the provider and requester needs to exist at the time of WS request.

Our framework proposes to use WS to separate the algorithmic logic and the client tool’s graphical user interface (GUI) in a way that logic could be reused in different applications running on various platforms. A VLE should only be able to call the services and manage the response. For instance, if there exists service S implementing algorithm A, then building a client (GUI) application C consuming S is enough to have a working tool in VLE. This is a rather small effort compared to development of stand-alone tools. The client C in a VLE allows learners to interact with service S (actually users normally do not even know that behind the scene there is a web service running). Thus, the implementation is distributed and does not have to be in the learning environment anymore; moreover can be thousands of miles away. The framework delivers a plot of possible implementations for creating LOs based on web services, and a set of such (prototype) tools, as the one discussed in Section 3.1, to further analyze the difficulties to overcome, such as integration in different VLEs. Our contribution can be seen as an approach to bring web services into VLEs as interactive hands-on simulator tools and enable the shift from teacher-centric learning process to a student-centric concept, where students are the engaged subjects of their learning process.

Applying the framework, the functionality, didactic aims and learning object implementations are separated into different cooperating “layers”, where they can be composed in whatever like combination to produce several tools for attaining different educational goals.

An overview of the framework is provided on Figure 1. The learning objects inside the VLE act as interfaces for available services outside the system. All instances are connected over the Internet, using HTTP(S) for data transfer. We can see a learner currently accessing a learning object “Behaviour of Digital Logic Gates”, described in Section 3.1.

Figure 1. Structure of the framework and an example

service being accessed by learner

74

3. Applying the framework in teaching

With technology evolving, microelectronic systems are becoming more complex, introducing design and testability issues as one of the major components of manufacturing costs of a product. To acquire necessary skills and become an experienced engineer students have to understand how the basic elements of digital logic (DL), such as AND, OR, etc. gates are working. It is very important to efficiently educate future engineers in this field. The framework presented in this paper is aimed on facilitating this goal.

At our university such engineers are mainly educated under the curricula of Computer Systems involving many hardware design and testability related subjects. This makes it important that students would get solid knowledge of the basics of DL as early as possible to be able to evaluate the behavior of elements and compose tests for detecting faults in larger combinational schemas at signal level. Besides theoretical lectures also practical experience through different exercises, where students can actually explore the elements of which sophisticated circuits are composed, are needed.

Even though the lectures are now made compulsory for first year students, this does not guarantee a good level of knowledge. The trend of not taking notes in lectures and counting on printable materials only adheres to insufficiency of theoretical knowledge clearly seen during practical labs, where students do not recognize basic elements, mix up their behavior or make other mistakes because of this. Therefore, to compensate for this, “technical toys” as tools, where students can easily explore the problem domain by experimenting and playing through certain scenarios, are needed. These tools must be generally available, for classroom and also home use. Commercial CAD-tools however are not suitable for interactive learning with the goal of understanding the essence of DL.

As the result of the e-EDU WSI [13], several educational web services have been and being developed based on standard SOAP and JSON format accompanied with appropriate clients as learning objects. Different implementations enable to test usability in different environments, such as e-EDU, BlackBoard and Moodle. As discussed, generally VLEs do not yet incorporate ways of consuming web services directly, or building service clients inside them. Nevertheless, it is still possible to successfully make use of LOs based on web services applying various approaches. Clearly, there is a dissatisfied need for features in VLEs that would allow consuming of web services in an easy manner.

3.1. Example web service: basics of logic gates

The example web service on basics of DL provides

a set of logic gates (AND, NAND, OR, XOR, etc.) for behavior exploration and knowledge testing. The web service has been developed according to the framework and in such a way that basic gates can be considered as atomic ones out of which more sophisticated services can be composed, taking advantage of the web services paradigm. In this way one can compose combinational schemas of several elements, as the output of one instance can be an input to another one – it is a question of making sequential service requests now. For example, one can easily build up an educational tool on triggers using the basic gates available in our web service (e.g. asynchronous SR trigger on NOR gates). Thus, describing basic logic gates as services, the latter can be used to compose whatever like schema for distributed simulations.

The WS and its accompanying simulator tool (GUI) discussed herein are meant for first year students in the subject Computers I, where IC technologies, combinational circuits and special hardware is taught. The course sets up all the necessary prerequisites for understanding the basics of DL, knowledge needed on further courses on design and testability related subjects. The main idea of the web service and its GUI tool is to provide an illustration of basic principles of digital logic gates, using graphical representation of the learning object and a web-based user-friendly interface, providing easy access to dynamic content and key points in theory, in a game-like tool for learning by doing. The demo tool shown on Figure 1 is not the only possible solution. Different tools exploiting our WS can be developed to assure that various educational goals are met. For instance, in the knowledge testing mode the truth table property of the service is not needed and thus not accessed.

The WS provides two modes enabling the GUI tool to be used either to acquire the correct signal values for the set input signals (x0..x3), or to test the correctness of proposed resulting signal value with the maximum length of 24 bits in a signal sequence. The service also provides a graphical notation and truth table for each element it supports on service level. This makes the GUI tool illustrative and comprehensive for the beginner and invites the student to experiment with it. The main didactic aim here is on understanding how the gates are behaving, when different signals are activated at their input, and also what are the notations and truth tables for specific elements. The service and demo client are available on the e-EDU WSI homepage.

75

The educational goals for the WS and GUI tool are: (1) identification of basic gates of DL and their behavior; (2) enliven “dry” theory and help to attain basic knowledge, thus raise the motivation to learn independently and improve ability to learn by rich variety of tools; (3) enable knowledge tests on DL gates behavior as a part of practical tasks defense, or before getting started with practical lab tasks, i.e., pre-check of necessary knowledge level; (4) provide a tool for self-testing theoretical knowledge; (5) allow to create different types of exercises, e.g., recognition of an element when the input and corresponding output signals are only known, or based on the given truth table; (6) enable re-use of the service to compose new elements out of existing ones, and by that ease the development of new learning objects.

Even though the tool has only been available since early this year, students have shown a great interest towards it. If earlier in the course they had to use CAD-software to explore the behavior of elements, or install some freeware (e.g. Digital Works) for home usage, then now it is all brought to them using the described learning object in a VLE. We have also received some feature requests, such as to add an interactive signal timeline generated according to the input and output signal values. The latter becomes very handy in case of having more complex schemas, e.g., combinational circuits (similar to those) students have to develop in the CAD-system during their labs. It then would enable learners to test the correctness of their design easily and fix errors before the task defense. 4. Conclusions

In this paper we have proposed a framework for creating interactive learning objects using web services. Applying the framework would easily allow to use already existing web services and tools in different virtual learning environments regardless of their development and location, provided that the services are publicly available. The framework is extensible for providing any kind of a learning object.

Developing educational learning objects as web services will increase their interoperability and reuse, at the same time reducing time and effort spent on creating such objects seldom for independent systems. Furthermore, applications developed using various languages and deployed on different platforms can automatically integrate and communicate, enabling sharing and using of learning objects, due to the use of web services and standardized input-output. Thus, we have gained interoperability of learning objects, which was one of the goals of the framework.

Finally, choosing the Internet as the platform for interactive applications brought to user in a browser window based on web services that can run anywhere on any technology or platform, is a promising approach for developing reusable learning objects such as interactive hands-on tools for web-based training.

Acknowledgement

This research was supported by the EU through the

European Regional Development Fund.

References [1] M. P. Papazoglou, Web Services: Principles and Technology, Pearson - Prentice Hall, 2007. [2] (2009) JSON website. [Online]. http://json.org/ [3] M. Hatala, and G. Richards, “Edusource: Interoperable Network of Learning Object Repositories,” in Proc. WWW2003, 2003, ACM. [4] K. Bahrami, M. Abedi, and B. Daemi, “A Web Service-Based Portal Framework for Distance Learning on Power Line Network”, in Proc. 6th Int. Conf. on Information, Communications & Signal Processing, 2007, p.1-5. [5] V. Pankratius, O. Sandel and W. Stucky, “Retrieving Content With Agents In Web Service e-Learning Systems”, Symposium on Professional Practice in AI, First IFIP Conf. on AI Applications and Innovations, 2004, pp. 91-100. [6] K. K. Thyagharajan and R. Nayak, “Adaptive Content Creation for Personalized e-Learning Using Web Services,” Applied Sciences Research, vol.3(9), pp.828-836, 2007. [7] Z. Xu, Z.g Yin, and A.E. Saddik, “A Web Services Oriented Framework for Dynamic E-Learning Systems”, in Proc. IEEE CCECE–CCGEI 2003, 2003, pp. 943- 946. [8] M. T. Su, C. S. W, C. F. Soo, C. T. Ooi, and S. L. Sow, “Service-Oriented E-Learning System”, in Proc. 1st IEEE Int. Symposium on Information Technologies and Applications in Education ISITAE '07, 2007, pp. 6-11. [9] A. A. Ajlan, and H. Zedan, “The Web Services Selection of Virtual Learning Environment Services”, in Proc. IADIS Int. Conference WWW/Internet 2007, 2007. [10] T. Robal, and A. Kalja, “e-EDU – An Information System for e-learning Services,” in Databases and Information Systems. Frontiers in Artificial Intelligence and Applications, 2005, vol. 118, pp.288-298. [11] T. Robal, and A. Kalja, “Moving studies to e-environments: a case study”. In Current Developments in Technology-Assisted Education, 2006, Vol. II, pp. 936 – 940. [12] T. Robal, and A. Kalja, “Enabling Students Contemporary Ways of Learning Using e-Supported Courses”, in Proc. 19th EAEEIE Annual Conference EAEEIE’08, 2008, pp. 14 - 19. [13] (2009) e-EDU Web Services Initiative website. [Online]. http://edu.pld.ttu.ee/WSI/ [14] Learning Technology Standards Committee (2002) Draft Standard for Learning Object Metadata. [Online]. http://ltsc.ieee.org/wg12/files/LOM_1484_12_1_v1_Final_Draft.pdf.

76