Real Time Interactive Instructional Systems for Computer Communication Technologies

by W. Thomas Miller, III

The rapid development and deployment of diverse communication technologies has resulted in rapid growth in employment in related areas within electrical engineering and computer science, both in New Hampshire and throughout the nation. As the result of its dynamic nature, however, this industry suffers more than many others do from problems of educating new employees and re-educating existing employees. In order to be effective, technical workers in the communication field must have command of large amounts of domain specific knowledge, most of which is beyond the scope of typical undergraduate degree programs in EE or CS. At the same time, the rapid rate of growth within the field makes it generally difficult to hire experienced professionals. Thus, it is necessary for companies to invest considerable effort and expense providing technical training to employees.

At the University of New Hampshire, the InterOperability Laboratory (IOL) is used by a community of over 100 vendors to verify the interoperability and/or conformance of their computer communications products. The services of the IOL are performed through independent focused interest groups in the lab called consortia. The IOL currently has consortia in operation to test the following computer communication technologies: 1394, Asymmetric Digital Subscriber Line (ADSL), Asynchronous Transfer Mode (ATM), Fast Ethernet (100Base-T), Fiber Distributed Data Interface (FDDI), Fibre Channel, Gigabit Ethernet, Internet Protocol (IPv6 and OSPF), Network Management, Token Ring, VLAN, and Wireless. The IOL also offers contracted testing services in Ethernet (10Base-T) and Full Duplex Switched Ethernet (FDSE), and 100VG-AnyLAN. While the consortium managers within the IOL are generally full time employees, the bulk of the lab's workforce is composed of UNH graduate and undergraduate students employed part-time during the academic year and full-time during the summer. These students generally move rapidly on to lucrative full-time positions in industry upon graduation, resulting in a very high turnover rate within the lab. In this dynamic atmosphere, the need to capture domain specific expertise in a form that facilitates the efficient transfer of knowledge is even more intense.

Automated instructional systems offer the promise of greatly reducing the costs involved in domain specific technical education, while at the same time increasing the flexibility available to employers in providing employees with educational experiences in the related fields. However, self-contained technical textbooks have long been available, and yet are not generally regarded as being successful in providing "autonomous" technical education. There is no reason to believe that computerized "textbooks" will be any more effective in this regard.

Last summer, the ECE Department in collaboration with the InterOperability Laboratory initiated an effort to design truly interactive automated instructional systems targeting communication technologies. These systems will use the power of the desktop computer combined with Internet services to present material effectively, combining text, graphics and simulations as appropriate without dependence on specific computer hardware or operating systems. However, in addition to the typical presentation functions, these instructional systems will have the capabilities of monitoring in real time the browsing activity of the student, of querying the student interactively, and of modifying the presentation of information in the future based on the student's past history of activity and responses. The intent is to provide a customized educational experience suited to the skill level and learning behavior of the individual student. Further, the intent is to develop modular tools and content, facilitating the development of course materials customized to the needs of an individual organization. These network based interactive systems could then be distributed widely via the Internet, or installed locally on an organization's own LAN or an individual's workstation.

Initial effort has focused on devising a general framework for developing real time interactive instructional systems. It was decided early on to work within the environment of Java program applets for the simulations and user interactive controls, with companion HTML documents containing the textual information, all viewed via commercial web browser software. While this opens up the possibility of hosting interactive instructional systems over the Internet, our major objective was to exploit the considerable commercial effort being put into design tools for Java and HTML, and to achieve a reasonable level of computer system independence within an organization's intranet.

Activities within the UNH IOL tend to focus mainly on issues of physical level signaling and network protocols for the different networking technologies. With this in mind, we developed two different Java based simulation engines. The first supports traditional analog and digital circuit simulations, to be used in training packages focused on physical layer signaling within networks. The accompanying figure shows a sample circuit that is part of a tutorial on Manchester phase encoding/decoding within traditional 10 MHz Ethernet networks. In this case, the circuit elements and connections are fixed in order to demonstrate specific signaling issues. However, simulations with moveable circuit elements and connections can also be presented to the student using the same simulation engine. This opens up the possibility of presenting virtual lab experiments within instruction packages, in which the student is asked to create a specific circuit function from a set of available elements, for example. The object oriented nature of Java programming allows the same simulation engine to be used across a wide variety of circuit types, and facilitates adding new circuit elements (new Java objects) without affecting existing simulations.

The second simulation engine developed in the project supports logical data packets (arbitrary streams of 1's and 0's) which propagate along network cables at specific velocities and bit rates. This supports the simulation of a variety of layered network protocols including issues of access control, network addressing, effects of propagation delays, and so forth. The results are true simulations rather than animations in the sense that students can, for example, generate arbitrary amounts and sequences of network traffic by clicking repeatedly on multiple workstations with the mouse. The accompanying figure in this case shows a simulation of two Ethernet LANs, forming two IP subnets, connected by a simple IP router. The Java programming language and standard libraries were created with user interactive systems in mind. This has facilitated the inclusion of convenience features such as pop-up help boxes into the simulations without excessive programming. Again, the object-oriented nature of the Java language allows the same simulation engine to support a wide variety of network simulations. Objects simulating the IP network layer inside a workstation can, for example, be layered on top of existing objects supporting Ethernet signaling and network access control.

The goal of the project is to go beyond simple tutorials with embedded simulations. The goal is to develop instructional systems which have the capabilities of monitoring in real time the browsing activity of the student, of querying the student interactively, and of modifying the presentation of information in the future based on the student's past history of activity and responses. With this in mind, the Java based simulations developed were built using a base set of code objects which connect transparently to a monitoring and control program running on a remote server on the LAN (or potentially on the same workstation). All student activities such as page to page browsing and interactions with the simulations are reported in real time to the server program via background threads within the code. In addition, the server can send commands asynchronously to the Java applets within the tutorial pages, remotely commanding or preventing browser links to new pages, for example. The server can also send down asynchronous pop-up dialog boxes that must be completed by the student before proceeding. These dialog boxes might contain simple queries about the student's preferences or recent activities, but might also contain quiz questions. The server can thus control what is presented to the student in the near future on the basis of sensed student activities or direct student responses to queries. Of course, the server monitoring and control aspects can be disabled to support more traditional statically linked tutorials.

This project is being carried out by ECE Department students under the direction of Professor Miller, and in consultation with Bill Lenharth and Barry Reinhold in the IOL. During the spring semester, Nick Soggu (MS '98) developed an interactive Java based circuit editor to facilitate the rapid layout of circuits for the existing simulation engine. This summer, two ECE seniors, Jon Scalera and Mike Dalton, are developing interactive tools for laying out the server queries and pop quizzes, and will be assisting in utilizing the circuit and network packet level simulations to support tutorials relevant to Fast Ethernet (100Base-T). At the same time, server-side logic and associated Java code supporting the remote querying and control functions of the server are being implemented. The first real trials of the system will occur later this summer when it is used as part of the training program for a new group of student employees within the IOL. It is hoped that experience in these initial in-house trials will lead to further refinements in the basic system, in preparation for a broadening of the subject matter and for distribution outside UNH to interested network vendors.