Increasing Engagement in Automata Theory with JFLAP ∗
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Increasing Engagement in Automata Theory With JFLAP ∗ Susan H. Rodger Eric Wiebe Kyung Min Lee Duke University NC State University Duke University Durham, NC Raleigh, NC Durham, NC [email protected] eric [email protected] Chris Morgan Kareem Omar Jonathan Su Georgia Tech NC State University Duke University Atlanta, GA Raleigh, NC Durham, NC ABSTRACT applied experience with theoretical concepts. JFLAP allows We describe the results from a two-year study with fourteen one to create and simulate several types of automata, to cre- universities on presenting formal languages in a more visual, ate and parse strings in grammars, and to experiment with interactive and applied manner using JFLAP. In our results proof constructions such as converting a nondeterministic the majority of students felt that having access to JFLAP finite automaton (NFA) to a deterministic finite automaton made learning course concepts easier, made them feel more (DFA) and then to a regular expression or regular grammar. engaged in the course and made the course more enjoyable. In JFLAP one can visualize the finite automaton or parse We also describe changes and additions to JFLAP we have tree in a graph format, interact with the automaton by run- made based on feedback from users. These changes include ning it with different input strings and see applications by new algorithms such as a CYK parser and a user-controlled creating a DFA as part of the SLR parsing process. parser, and new resources that include a JFLAP online tu- Many other tools for experimenting with automata theory torial, a wiki and a listserv. have been developed. Turings World[2] is for experimenting with Turing machines. Forlan[24] and Emulator[26] are for experimenting with regular languages. The tool jFAST[27] Categories and Subject Descriptors allows experimentation with finite automata, pushdown au- F.4.3 [Theory of Computation]: Mathematical Logic and tomata and Turing machines. Grinder[9] focuses on finite Formal Languages Formal Languages; D.1.7 [Software]: Pro- state automata. RegEx[5] allows experimentation with reg- gramming Techniques Visual Programming ular expressions. Taylor[25] explores several types of ma- chines. Ross[7] is developing a hypertextbook for many top- General Terms ics in automata theory. Many of these tools focus on a small set of topics. JFLAP is a software tool under development Theory for over 17 years to incorporate an extensive number of top- ics in automata theory in one tool. Keywords In the last few years, several tools have been developed JFLAP, automata, formal languages, pumping lemma, CYK in Algorithm Visualization for different areas of computer parser science with the majority for algorithms and data struc- tures. Examples of these include Balsa-II [6], XTango [21], Samba [22], AACE [8], Animalscript [19] and JHAVE[13]´ 1. INTRODUCTION for algorithms animation, tools for graph theory such as The formal languages and automata (FLA) course has tra- Guess [1], and tools for discrete mathematics such as Com- ditionally been taught with little engagement or feedback, binatorica [15, 20], SetPlayer [3] and LINK [4]. using pencil and paper exercises limited to small problems. How effective are such tools in the learning process? There We have developed JFLAP[18, 17], educational software are some results in this area, but there is still much research used in this course to provide a more visual, interactive and to be done. A small study using Samba [23] showed that there was a learning advantage for students who interacted ∗The work of all the authors was supported in part by the National Science Foundation through NSF grant DUE- with algorithm animations in a lab. In [10] a metastudy 0442513 of 24 experimental studies on the educational value of al- gorithm visualization is presented. Nine of the studies had no significant differences detected, but the remaining 15 had results such as participants viewing or constructing anima- Permission to make digital or hard copies of all or part of this work for tions scored significantly higher or outperformed in some personal or classroom use is granted without fee provided that copies are way. In [14] an ITICSE Working Group explored the role not made or distributed for profit or commercial advantage and that copies of visualization and engagement in computer science educa- bear this notice and the full citation on the first page. To copy otherwise, to tion and proposed several hypotheses to compare the types republish, to post on servers or to redistribute to lists, requires prior specific of engagement of 1) no viewing, 2) viewing, 3) respond- permission and/or a fee. SIGCSE’09, March 3–7, 2009, Chattanooga, Tennessee, USA. ing, 4) changing, 5)constructing, and 6) presenting, with Copyright 2009 ACM 978-1-60558-183-5/09/03 ...$5.00. the hypothesis that the engagements offer significantly bet- useful tool to design, run and interpret simulations. Specific ter learning outcomes the higher the number associated with questions from the usability survey are combined with year it (with presenting the best outcome). 2 and shown in the next section. How effective is JFLAP in enhancing the learning pro- Selected questions from the software implementation sur- cess and what additional value might JFLAP add to the vey shown below show that the majority of students used FLA course? This paper describes a two-year study of four- JFLAP to study for exams and thought JFLAP helped them teen universities using JFLAP in their FLA course including to get a better grade. feedback from both students and faculty. In Section 2 we give an overview of the study and its Question YES/NO No. % results. In Section 3 we describe changes and additions Did you use JFLAP software YES 20 55% to JFLAP based on feedback from users in our study. In to study for inclass exams? NO 16 45% Section 4 we provide an analysis of the worldwide usage of Did you feel you had time to YES 33 94% JFLAP, and in Section 5 we give concluding remarks. learn how to use the JFLAP NO 2 6% software? 2. JFLAP STUDY Did you feel that using the YES 3 8% software took time away from NO 33 92% 2.1 Overview other study activities? Did the time and effort it took YES 23 64% Our two year JFLAP study was held from Fall 2005 to to use JFLAP help you get NO 13 36% Spring 2007 and included twelve universities the first year a better grade in the course? and an additional two universities the second year. The four- Was it easier to use JFLAP software 30 83% teen schools were Duke University, Emory University, Fayet- software or was it easier to by hand 6 17% teville State University, Norfolk State University, Rensse- draw it out by hand? laer Polytechnic Institute, Rochester Institute of Technol- ogy, San Jose State University, United States Naval Academy, Did you feel you would have YES 18 50% University of California Davis, University of Houston, Uni- done as well in the course NO 13 36% versity of North Carolina, University of Richmond, Vir- if you had not used JFLAP? NA 5 14% ginia State University, and Winston-Salem State University. These schools included a large mix of public and private, The attitudes survey showed that students were confident large and small schools with several HBCU schools to in- in their abilities as one would expect for upper level com- clude a racially diverse population. puter science majors, and enjoy engaging in the work and In the summer of 2005 we held a workshop with 18 partic- problem-solving that is part of their course work. ipants including mostly faculty adopters, three evaluators, The pretest and posttest given at the beginning and end and three student research assistants. A followup workshop of the semester showed that the majority of students learned was held in the summer of 2006 with 17 participants, five of key content in the course. There were too few responses and them new. All fourteen schools participated in at least one no control group this year to statistically gauge the efficacy of the workshops. However, with the nationwide trend of en- of JFLAP for improving learning. rollments dropping in computer science and the automata At the end of each semester, the research team conducted theory course an optional course at some schools, not all structured telephone interviews with faculty adopters and schools were able to participate in the collection of data due at the end of the year a focus group of faculty during the to low enrollments or courses not held every year. second workshop. We give a summary from these faculty Data was collected from students and faculty adopters discussions. through knowledge tests, surveys, structured telephone in- terviews and face-to-face focus groups. • The faculty felt strongly that JFLAP not be used as part of exams. The reason cited in some cases had 2.2 Results of Study - First Year to do with concerns about cheating and/or the tests The first year of the study in 2005-2006 we were able to were all paper and pencil. One instructor did use it collect data from 55 students (pretest) and 33 students( for a test but found that students spent too much time posttest) at the seven schools: Duke University, Norfolk trying to perfect their machines. State University, University of Richmond, University of Hous- ton, Virginia State University, Fayetteville State University • JFLAP was mostly used in homework and some as and University of California Davis. The data collected from part of in class demonstrations. For those who did not students included a pre and post knowledge test, and a sur- use JFLAP as part of the class lecture/demonstration, vey of computer science attitudes, JFLAP implementation their reasons were varied but usually centered around and usability.