The Third International Conference on the Learning Sciences (ICLS-98)
December 16-19, 1998
Georgia Tech, Atlanta


An Natural Networked Computer based Integrated Teaching/Learning Hyper-environment
Jianhua Ma and Runhe Huang

To promote the revolutionary education, a fundamental and challenging problem is to establish an effective and natural networked computer based integrated educational system for systematically supporting all teaching and learning activities in future real/virtual schools and universities. Our project, CHEER (Computer-based Hyper-Environment for Educational Reformation) which started in 1997, aims at designing and developing an natural networked computer based integrated teaching/learning hyper-environment. It is emphasized that five environments, the lecturing, the exploring, the collaborative, the evaluation, and the administration, are naturally integrated to adapt and map teachers/students thinking features: jumping and simultaneous. This paper mainly describes our current progresses on developments of the exploring, the collaborative and the evaluation environments.

Visualizing Earth
Daniel Barstow

This paper presents the findings of two research and development initiatives on the educational use of images and visualization technologies to help students explore and learn about Earth. Visualizing Earth is an NSF-funded research project focusing on cognition and perception in the use of remote-sensed images and visualizations. In a three-year sequence of ìTalking Imagesî, ìExploring Imagesî and ìTransforming Images,î we have explored how students make meaning of images, including perceptions and misperceptions of 3-dimensionality, scale, point-of-view, symbolic representation, and change over time. EarthKAM is a closely-related NASA-funded project in which students have direct access to a digital camera flown on the space shuttle. EarthKAM engages students in three components: 1) learning about the shuttle, ground tracks and targeting, 2) learning to work with images and 3) designing and conducting investigations. Through this combination of cognitive research (Visualizing Earth) and program development (EarthKAM), the investigators have been able to conduct a multi-faceted research and development initiative, exploring the power of images and visualization technology in Earth and space science education.

An Instructional Design Model for Web-based Curriculum
Kevin Smith and Michelle Kobza

The CLASS (Communications, Learning and Assessment in a Student-centered System) Project is building a complete, accredited, high school diploma sequence for the World Wide Web. The Department of Distance Education of the University of Nebraska-Lincoln is recipient of $18 million in federal funding to develop the sequence. When completed in 2001, 54 CLASS courses will be available for students to complete these requirements. Founded in constructivist learning theory, the CLASS courses utilize interactive designs and student-centered activities to facilitate learning. The seamless design enables ongoing self-checks, evaluations and assessments, which empowers the student to interact with the courses in sequences or patterns that match individualized learning styles. CLASS courses are reaching to utilize the Web to its fullest instructional advantage. Content is written specifically for the Web, scaffolded for broader and deeper experiences with the subject matter and designed so the student has choices of direction and activity. Integral to the CLASS learning environment is wide use of original video and audio. Animated tutorials and interactive self-checks provide modal learning experiences. Each CLASS course illustrates yet another learning method enabled by the dynamic, multimedia capabilities of the Web and includes extensive World Wide Web links to enhance and reinforce learning. The CLASS homepage can viewed at

Online Ecology
Timothy W. Peters Karen E. Hopkins

This paper presents Online Ecology, a web based ecology lesson based on a social constructivist, interdisciplinary, multicultural philosophy. Students demonstrate their masteryy of the basic concepts of ecology by constructing a model of their own local ecosystem which is shared over the Internet and serves as a resource for other students and teachers around the world. Online Ecology is an interdisciplinary activity that ties all curricular areas (science, social studies, language arts, math, art, and PE) around the Ecology theme. It presents material reflecting a multicultural point of view. The activity is linked to the Agayuliyararput: Our Way of Making Prayer Yup'ik mask online exhibit.

Why? When an Otherwise Successful Intervention Fails
Robert Waters and Mike McCracken

Problem-Based Learning (PBL) has been an effective technique in developing self-directed learning and problem-solving skills in students ñ especially in the medical school environment. This paper looks at some preliminary results of an ethnographic study of students in a software development environment trying to use PBL, where the historic results have not been as successful as those documented in other fields. Our findings indicate that students need explicit training in group dynamics, students tend to rely excessively on existing knowledge, and they focus almost solely on product-related issues versus process-related ones. We then present some suggested improvements and future planned research.

Learning Perspectives
Gerry Stahl

Learning as a socially situated activity involves an interplay between group and personal perspectives. Knowledge is constructed within nested perspectives that reflect social practices, shared meanings, and individual understandings. Educational software to support collaborative learning can represent these perspectives for learners to help them reflect on their own perspectives and negotiate group perspectives on knowledge. By providing different views on a shared and growing knowledge base, perspective-based software distinguishes different peopleís ideas to make clear each personís perspective on common topics. Individuals work on their own ideas, share them, and propose them for group adoption. The convergence needed for successful collaborative learning emerges from a process of negotiation in which divergent positions are distinguished and discussed. Students using the software have a representation for thinking about learning perspectives, a mechanism for organizing their own perspectives in relation to those of their classmates, and a tool for mediating formative involvements in collaboration, research, and negotiation. ìLearning Perspectivesî proposes perspectives on learning as a social, linguistic, and perspectival process. It introduces a software mechanism for representing and organizing group and personal knowledge to scaffold learnersí learning about perspectives. Then it illustrates the use of perspectives for learning in project-based classrooms.

A Preliminary Step toward Developing ID Assistant as an Aid for Automating Instructional Design
Youngcook Jun

This paper describes ID Assistant which is a job-aid instructional design program. The ID Assistant was originally designed as an automated presentation tool that makes teachers feel comfortable in building multimedia materials in Korea. With this system, teachers are apt to classify, search and retrieve multimedia resources stored in database. In addition, ID Assistants templates help teachers organize text and audio/video clips in elaborated sequences relevant to their teaching plans. Our system thus falls into the category of job-aid automated instructional systems. ID Assistant is especially suited for teachers direct presentation of multimedia materials, using devices such as TVs or projectors in the classrooms. The final part of this paper presents how to modify the ongoing system in the future.

AulaNet: An Object-Oriented Environment for Web-based Education
Sergio Crespo, Marcus Felipe M. C. da Fontoura, and Carlos Jose P. de Lucena

As yet there are no specialists in the application of information technology to education and training. However, this is one of the fastest growing areas on the Internet, due to the recent perception of the enormous potential for the use of Web resources for this purpose. This potentiality has attracted the attention of researchers in industry and the academic world, which are currently developing various models and products for Web-based education and training. This paper presents AulaNet, an environment for the creation and maintenance of Web-based courses designed for the layman, highlighting its architecture and design model.

Peer Collaboration and Virtual Environments: A Preliminary Investigation of Multi-Participant Virtual Reality Applied in Science Education
Randy Jackson Wayne Taylor William Winn

In researching educational applications of virtual reality, it is now possible to place several students within a single virtual environment simultaneously. This raises questions regarding the impact of collaboration within the virtual environment on overall learning processes. A preliminary study of 18 sixth graders was conducted for the purpose of examining peer collaboration within a virtual environment (VE). Students worked in pairs while investigating the concept of global warming within a fully immersive, 3-D, virtual reality based model of Seattle called Global Change World (GCW). It is concluded that the students thoroughly enjoyed their experience with GCW. It was apparent that peer collaboration played a significant role in regards to the level of student engagement within the VE. The ability of the students to communicate with each other via an intercom assisted dyads in effective navigation through the virtual world and performance of requested tasks. This preliminary study found that, while the potential for GCW to facilitate collaborative learning experiences appears to be great, further research is needed that will focus more closely on the impact of peer collaboration on preconceived or "naive" scientific concepts as well as the possible conceptual change inspired by collaboration within GCW.

The Norms of an Educational Organization: How Practices May Change in the Context of Technological Innovation
Valerie L. Worthington Yong Zhao

In the summer of 1997, researchers at a large midwestern university facilitated the pilot test of a Web-based document management system for a large educational research organization. Although it was originally designed simply to support the efficient collection, review, and coordination of proposals to present original research at this organizationís annual meeting, the system and its Web format eventually turned out to have implications for the broader practices and protocols of the organization. This study represents one part of an ongoing investigation of the significance of this Web-based system in the life of the organization. It is our hope that by considering the implications of this particular Web innovation, we can begin to draw more general conclusions about the influence of Web technology on activity within the structure of social organizations. The focal questions of this project are: How does the introduction of this Web-based system into existing, non-computerized practices violate the expectations and assumptions of organization members? What are the implications of this violation for membersí perceptions of the goals of the organization and their role within it?

Introducing Science WRITE (Science Writing and Revision Interactive Technology Environment) (Science Writing and Revision Interactive Technology Environment)
Laurence Greene, Marie Boyko, Sally Susnowitz, Kirsten Butcher, Eileen Kintsch, and Walter Kintsch

We propose to present an overview of Science WRITE, a computer-based learning environment designed to help undergraduates solve the problems they face when learning to write in science. Research reveals that these problems are intimately linked to the extraordinary cognitive demands of producing effective writing. Existing books and on-line resources for teaching scientific writing generally do not address these process-based demands; instead, these resources focus on grammatical and stylistic rules for writing as well as the format of final products. In contrast, Science WRITE's curriculum, which is based on cognitive research, supports students in carrying out the mental operations that expert writers employ. Accordingly, we are developing Science WRITE to help students acquire discourse and procedural knowledge through working with modules that reflect cognitive subprocesses in writing. The modules include models of expert processes and products, tools to support students in executing and monitoring expert processes, and tools for social knowledge building and peer review. Our purposes for this presentation are to introduce the components of Science WRITE, relate its learning activities and tools to cognitive research on writing processes in novices and experts, present our goals for student learning, and provide an overview of plans for our research program.

The Schema Compiler
Mark K. Singley

Interpreting and Animating Graphs for an Audience
Aachey Susan John

Mathematical representations are commonly used to make claims about situations, to show the way things are or should be, or to defend a certain position or action. Critically, these are not inherent features of the representations themselves but are the products of how individuals or groups interpret them. Following how students learn to interpret mathematical representations contributes to an understanding of the discursive practices involved in producing mathematical claims and how these practices develop in the context of math classrooms. In this paper, I present two cases where middle school students in different classrooms interpret the same graph for an audience of their classmates. In each case, the students construct narratives which propose different ways of understanding what is represented by the graph. Through close examination of the ways that the students construct their narratives, I show how they propose particular kinds of listeners. Using their proposed audience and the intended purpose of the presentation as a resource, I argue, directly affects the scope of the claims made about the graphs. In the first case, I show the construction of a 3general2 reading of a graph, and in the second, a 3specific2 interpretation of the same graph.

On-line Collaboration and Data Visualization in Classrooms: Investigating the Social Context of Learning
Katherine McMillan Culp, Dr. Margaret Honey, Kallen Tsikalas, and Wendy Friedman

Although a wide range of high-quality software tools to support collaboration and data exploration are being produced for the K-12 community, persistent challenges--probably related to issues of training, support, fit with curriculum, and teachersí beliefs about studentsí abilities-- limit the scope and depth of implementation. This paper draws on the researchersí experiences with the collaborative tool Portals to describe a newly emerging line of in-classroom research which will seek to better understand the iterative relationship among the adoption of an innovative collaboration and/or visualization tool; the character of the learning environment; and the quality of student inquiry. The goal of the research is to re-envision and better understand the nature and the goals of the intervention being attempted through specialized software development.

The Effects of a Virtual Reality Interface on Text Comprehension
David VanEsselstyn John B. Black

In a computer based experiment, groups were exposed to either a textual walking tour of the Saint John the Divine Cathedral, the same walking tour accompanied by black and white photos of the cathedral that coincided with the text, or a virtual reality experience accompanied by the same text. Participants were then tested on the factual, imagistic, and mental model knowledge they were able to obtain from the experience. In the test, participants in the text and photo groups were outperformed by the virtual group on the factual questions and the imagistic questions. The virtual group also took significantly more time inside the program than the other two groups. The text group outperformed the other groups on the mental model task. Issues around memory encoding and retrieval are discussed in relationship to the findings.

A Principled Approach to the Design of a CSCL Tool for Project Based Instruction
Anthony J. Petrosino and Jay Pfaffman

In this paper, we illustrate the reflexive nature between theory and practice (Glaser, 1994) in terms of the development of CSCL1 software for a problem to project-based environment (Baron et al., in press; Soloway, Krajcik, Blumenfeld, and Marx, 1996) known as Mission to Mars (Petrosino, 1994). Specifically, we will discuss the development of a computer tool known as the Mission to Mars Webliographer which allows children and adults to collaborate and synthesize Internet resources for research in context rich, sustained learning environments. In communicating this process, we have found the work of Koschmann et al. (1996) to be of particular assistance in providing a principled approach to the design of technologies for CSCL.

Hypermedia Design Principles for Case-based Teacher Education Environments
Matthew Koehler, Anthony J. Petrosino, and Richard Lehrer

Case-based methods of teacher education offer the promise of developing forms of knowledge useful in everyday practice. However, most implementations of case-based pedagogy for teachers rely on traditional media and means. We have been developing and assessing the utility of hypermedia-based tools for case-based learning. Briefly, our evolving design principles in case design call for the case to be authentic and narrative in form. The case should be long enough to establish some form of instructional corridor. The cases also should have additional supporting video to provide multiple examples (telescoping) and should help teachers come to view themselves as active agents in their studentsí learning. Along the way, we have confronted a number of design challenges, including consideration of the very nature of a case and appropriate means for anchoring case-activity to important mathematical ideas. Accordingly, we describe an evolving set of design principles for case-based instruction with hypermedia and report some of the ways in which we assess learning with these tools. Finally, we relate our development efforts to other research about case-based learning.

TEACHING WITH A COMPUTER AND LEARNING WITH COMPUTERS: A case study of an elementary classroom during Kids as Global Scientists '97 and '98
Hee-sun Lee & Nancy Butler Songer

The study presented in this paper is a two-year longitudinal ethnographic study, blended with survey and interview methods, in a fourth grade elementary classroom, where a teacher implemented the Kids as Global Scientists (KGS) program in 1997 and 1998. During the two years, the classroom improved computer technology, from one laptop computer and one modem, to seven computers with full Internet connection, enough for seven groups of three to four students to use in their activities. The purpose of this paper is to describe (1) how an in-service teacher managed his class and came to change his pedagogy as he understood more about instructional approaches in an innovative science program and used more technology available to him, and (2) how students reacted to the teacher's change.

Electronic Discourse as an Essential Component for Building and Sustaining Electronic Community of Science Learners
Soo-Young Lee The University of Michigan 1228 School of Education Building 610 E. University Ave. Ann Arbor, MI 48109 734-647-2078 Nancy Butler Songer The University of Michigan 1332 School of Education Building 610 E. University Ave. Ann Arbor, MI 48109 734-647-7369

This study examined characteristics and patterns of electronic discourse on a web-based discussion tool, called the Message Board. Over 4,000 students and 60 scientists who participated in the Kids as Global Scientists, an Internet-enhanced atmospheric science program, exchanged the total of 4,464 messages during eight week period. In order to identify the unique characteristics of electronic discourse in K-12 educational settings and how the electronic discourse is similar to or different from the traditional classroom discourse, patterns of discourse and content of messages were analyzed. Compared to a teacher-dominant traditional classroom conversation, more student-student communications were encouraged on the Message Board. Developing social glue among participants and building identity as members of the electronic community of science learners were key factors in making electronic discourse more productive. From the beginning, participants shared their common goals, studying weather phenomena around them, by talking to each other and introducing their weather and surroundings as well as themselves. The awareness of a sense of community encouraged them to work together and share each other's experiences as valuable resources for developing understanding. We also found that a well-coordinated curriculum could support building the active electronic community of science learners.

On-Line Professional Development and Mentoring: Initial Evaluation
Susan M. Williams, Susan R. Goldman, Marcy Singer-Gabella Charles K. Kinzer, and Victoria J. Risko

The goal of the On-Line Professional Development and Mentoring (OPDM) project is to explore new forms of professional development that make use of new understandings about learning and advances in telecommunications technology. OPDM is designed as an on-line forum where practicing teachers can learn from each other and from mentors as they engage in sustained reflection and discussion about actual practice OPDM is designed as a netcourse, i.e., a seminar or course of study using the Internet as the primary way to distribute materials, make assignments, collect student work, and carry out discussions. The course is anchored in the study of classroom artifacts including actual samples of middle school student writing and writing samples from participantsí own students. Participants studied these artifacts in order to understand what they revealed about teaching and learning. Initial evaluation of the first conduct of the OPDM netcourse revealed that participants were eventually able to overcome numerous barriers to participation created by unfamiliar technology. Barriers created by a lack of community were more difficult to surmount. Teachers found themselves involved in a discussion with strangers who were experts in their profession. As a result, they were often unwilling to have the kinds of frank discussions necessary for changing deeply held beliefs.

Relations and Functions: Combining Mathematics and Writing In a College Classroom
Bran, Tobi M. Burn, Helen Caster, Angela

"Relations and Functions" is an interdisciplinary course which combines college algebra (function theory) and writing (freshman composition and research and persuasive) in one environment. This program has aided students in their educational pursuits of each subject, offering an experience atypical of the classes as traditionally instructed. "Relations and Functions" parallels a real-world setting, providing the framework for natural exploration and extensive social interaction. Various tools such as the Internet, Excel, multi-media visuals, and independent research provide students with exposure to numerous learning modalities. With an emphasis on current technology and collaboration with others, the ultimate social context is provided. This course not only provides students with diverse perspectives on math through groupwork, but also the skills to write and explore math for themselves and to successfully communicate it to others. The course prepares students for additional education as well as future careers.

Web Librarian: A Book Recommendation System to Address Reading Problems in Middle School
Jody S. Underwood

Web Librarian is a web-based book recommendation system designed to help children select books that are interesting to them, and to help them learn effective book selection strategies. It addresses the problem of middle school students often reading below grade level. These students often use ineffective strategies for selecting books. We hypothesize that if they read interesting books that their reading achievement would improve. Based on cognitive and social considerations, we decided that a book recommendation software system could help. Existing web-based book recommendation systems do not fully take into account the needs of infrequent readers. After piloting Web Librarian in an inner-city middle school, we found that students and educators like it, but some changes need to be made to incorporate it into the curriculum.

Analysis of Hybrid Distance Learning: Corporate Employees in Academic Courses
Stephen B. Gilbert, Loan Ngo, Lisa Abrams

Organizations have spent vast amounts of money to equip employees with new knowledge that they can apply on the job, but many education efforts fail. MIT's System Design & Management program (SDM) is a master's degree program in engineering and management for industry employees that hopes to overcome some of the typical barriers to organizational learning. The authors have recently collected a variety of data on the SDM program, and this paper discusses some of our results so far. Our findings focus on the students' ability to apply their learning in the workplace and the technology used for distance learning. We suggest that our analysis can be useful for both for other distance learning programs and for educators who struggle to integrate the learning experience with the environment in which it will be applied.

Promoting Systemic Reform with Embedded Technology
Ron Marx Phyllis Blumenfeld Barry Fishman Joseph Krajcik Elliot Soloway

In this paper we describe an approach to systemic change that is guiding our efforts to introduce inquiry supported by technology in all middle schools in Detroit, and what we have learned after a year in this large urban system. We begin with a description of the model that we have created to guide our work. Following this, we discuss how curriculum materials design and revision serves as a vehicle for embedding technology in the day-to-day experience of teachers and students. We then present an example of a series of issues and problems that arose as we applied our model to scale up the networking infrastructure in the district. We conclude with a discussion of research and development issues that remain. These efforts are part of the Center for Learning Technologies in Urban Schools and the Detroit Systemic Initiative in science supported by NSF.

Analysis of a video-mediated communication system for hospitalized children
Laurel A. Williams Dr. Deborah I. Fels Graham Smith Jutta Treviranus Dr. Roy Eagleson

A remote controlled video conferencing system (VCS), P.E.B.B.L.E.S. (Providing Education By Bringing Learning Environments to Students), was developed to allow a student access to his/her regular class from the hospital and to provide the student with a classroom presence. In the classroom, the student is represented by a simple and child-friendly robotic device. Remote control is provided by a game pad, which allows the child to direct P.E.B.B.L.E.S. The results of two case studies are reported in this paper. These studies examined the effectiveness of P.E.B.B.L.E.S. in allowing a student to participate in typical classroom activities and in providing the student with a sense of presence in the classroom. Results indicate that the system can be used relatively successfully when performing the majority of the required activities. The study participants reported an overall positive experience using the system and remote users appeared to have a sense of presence in the classroom.

Mediated Conversations for Cognitive Apprenticeship:A Visual Tool for Instructional Designers
Tom Carey Kevin Harrigan Antonia Palmer

We have developed a visualization tool, called the MCCA Visualization Tool, that allows instructional designers to represent mediated conversations in the cognitive apprenticeship model of learning. Results from usage of the tool suggest that it is an effective aid for both novice and experienced instructional designers: novices can employ diagrams to incorporate cognitive apprenticeship principles in their designs, and experienced designers can use the abstraction to acquire a gestalt view of the learning conversations for discussion and critique. In this paper we discuss the theoretical framework used to guide the development of the tool, explain its components, and show its application to two cases of instructional design.

Bridging the gap between motivational research and progressive education: A framework for designing highly engaging learning environments
Diana Joseph

There exists an intellectual gap between the motivational research community and the progressive learning environment design community. Motivational researchers interested in education have tended to focus on providing advice to teachers and instructional designers working in traditional classroom settings. Learning environment designers interested in motivation have tended to focus on activity design, describingmotivation in general terms, rather than using the constructs developed in the motivation literature. I have developed the ìPassion curriculumî design approach, a framework for learning environment design based on four design principles that bridge between the motivational literature and the progressive education literature. During 1997 and 1998, I built and implemented a prototype passion curriculum, the Video Crew. In this paper, I describe the passion curriculum design principles and the specific passion curriculum structures that ensure that those principles are met, and I illustrate the structures and principles through vignettes from the Video Crew.

Addressing the Challenges of a Social Simulation with Computer Supported Collaborative Learning (CSCL) Tools
Todd Reimer, Daniel C. Edelson

Abstract: Participating in social simulations requires opportunities for communication which are often unavailable in most high schools. This paper describes a teacher's experience addressing this communication problem using the Collaboratory Notebook in a Legislative Simulation he designed . The Collaboratory Notebook is a networked, hypermedia collaboration environment designed to allow students to share their thoughts directly with a larger audience consisting of their peers, teachers, and experts in the field. The paper analyzes the needs of the Legislative Simulation and describes how the Collaboratory Notebook was used in an attempt to address them. Covering a three week trial, the paper concludes with preliminary observations, conclusions, and future research questions.

The Abner Project: Goal-Directed Inquiry in a Simulated Environment
Jessica Zirkel, Benjamin Bell, Sholom Gold

The Abner Project is a World-Wide Web-based learning environment that provides an explicit framework for historical and contemporary inquiry by situating learning within an exhibit design context and allowing a student to adopt the role of curator. Abner uses artifacts from the collections of the National Baseball Hall of Fame to spur the examination of issues of civil rights, gender equity, political power, popular culture, and foreign affairs. The software provides an arena for students to explore and analyze Hall of Fame artifacts, develop findings, and synthesize these findings into a coherent, shareable and interactive presentation. Instead of passively receiving discrete, disconnected, and pre-digested facts from a static source like a textbook, students using Abner actively select, interpret, and modify factual information from a dynamic database, building an exhibit reflecting their understanding of a part of a larger historical or cultural domain. By designing an exhibit with Abner, the student-as-curator is "doing" history, that is, learning about a particular facet of an era by actively interpreting primary sources of historical information.

Why and How Students Work with The Math Forum's Problem(s) of the Week: Implications for Design
K. Ann Renninger

This paper describes findings from an action-research project that is part of the on-going evaluation efforts of The Math Forum, an NSF-funded virtual resource center for mathematics education ( The study reported here was designed by Math Forum staff for the purpose of detailing possible directions for project development. Following a description of the Problem of the Week (POW) project, findings from study of why and how students work with the POW are reported. In general, findings from this study indicate that differences among students in terms of gender, accuracy of problem solution, and interest for mathematics do not predict why students do the POW, although they do predict how they do it. Discussion focuses on what these findings contribute to our knowledge about student learning and their implications for the design of interactive projects such as the POW.

"Who is she?" Designing a beginning literacy computer-based learning enviornment to reflect the lived experiences of low SES african american girls
Nichole D. Pinkard

Building community mentoring relationships through middle school science
John M. Carroll Dennis C. Neale

Toward a Community of Evolving Learners
Elizabeth Sklar and Jordan B. Pollack

We discuss the "co-evolutionary learning method", applied to human learning, as a means toward a mediated, competitively motivated, educational environment on the Internet. This method was developed in our work with machine learners, where we have been examining environmental characteristics that enable successful and effective learning through ``self-play'' in games. Critical features include the ability to continually provide tasks just beyond or just within a learner's grasp. We carry these observations into the human education arena, using them to help us enable a community of evolving learners (CEL) on the Internet. This paper describes the design of the CEL system.