IEEE TRANSACTIONS ON EDUCATION, VOL. 51, NO. 1,FEBRUARY 2008 61 Providing Students Hints and Detecting Mistakes Made by Students in a Virtual Experiment Environment Jia-Sheng Heh, Member, IEEE, Jyh-Cheng Chang, Shao-Chun Li, and Maiga Chang, Member, IEEE Abstract—This study models a virtual experiment environment (VEE) by adopting the Petri net theory. Petri net-based VEE can record the experimental activity processes of students and eval- uate the students’ learning abilities. Petri nets can be used as vi- sual-communication aids, and are similar to flow charts, block di- agrams, and networks. Consequently, the experimental steps can be easily transferred to the Petri net model. Analysis of the col- lected data with the Petri net model indicates that errors made by students during experiments can be categorized into two major types, namely, measuring and procedural errors. This work imple- ments a Petri net-based VEE for physics experiments. A total of 72 third-year junior high school students participated in this re- search. Both pretesting and posttesting are performed to ensure that the Petri net-enhanced VEE is useful. Index Terms—Learning control systems, learning diagnosis, Petri nets, student experiments. I. INTRODUCTION V IRTUAL experiment environment (VEE) in e-learning provides students with a visualized social learning envi- ronment by simulating experiments on the Internet [1], [2]. A VEE includes a set of simulated virtual equipments for students to perform experiments [3]. Researchers recently classified VEE systems into three major types: real lab, visual lab, and virtual lab. 1) Real lab requires a set of external experiment devices and a software kit [4]. 2) Visual lab utilizes video-media and some manipulation tools to cover both the realities of a real laboratory and conveniences of a simulated laboratory (also called a software laboratory) [5], [6]. 3) Virtual lab simulates experiments in either 2-D or 3-D forms [7], [8]. Although VEE offers students an environment to perform lab- oratory experiments on the Internet, teachers cannot easily mon- itor the experiment progress or provide appropriate instructions to students in real-time. Many interactive intelligent tutors or Manuscript received May 18, 2006; revised April 25, 2007. J.-S. Heh and J.-C. Chang are with the Department of Information and Com- puter Engineering, Chung-Yuan Christian University, Chung Li 32023, Taiwan, R.O.C. (e-mail: jsheh@ice.cycu.edu.tw; eoda@mcsl.ice.cycu.edu.tw) S.-C. Li is with the Department of Computer Science and Information Engineering, MingDao University, Peetow, ChangHua 52345, Taiwan, R.O.C. (email: learry@gmail.com). M. Chang is with the School of Computing and Information Systems, Athabasca University, AB T9S 3A3, Canada (e-mail: maiga@ms2.hinet.net). Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TE.2007.901977 Fig. 1. Four parts of a VEE. environment solutions in VEE have been presented to solve this problem [9]–[12]. The main objective of this research is to create a VEE in which students’ activities can be recorded during experi- menting, and students’ experiment processes can be evaluated in real-time. This investigation applies a Petri net to model experiments in order to allow comparisons between the experi- ment processes of the students and teacher. The VEE can then automatically identify the errors made by students and provide timely assistance. The VEE in this research is a physics experiment envi- ronment. The physics experiments cover the physics of the third-year junior high school in Taiwan, including measure- ment, velocity, and free-falling. Seventy-two third-year junior high school students participated in this study. II. VEE AND PETRI NET A. VEE As mentioned in the previous section, an interactive VEE comprises four major integral parts, namely, the knowledge base, user interfaces (UIs), teaching materials, and interactive protocols. The diagram in Fig. 1 indicates that these four components cooperate with each other [12], [14]. Learners can perform many scientific experiments with appropriate tools and UIs. The teaching materials and UIs should conform to some basic educational concepts, such as the seven problem solving stages and skills in scientific processes [15]. Experiment agents and/or the system might be able to read the teaching materials directly without supervision, and 0018-9359/$25.00 © 2007 IEEE