Navigation is the journey that brings the precision and accuracy especially for the trip from one place to many destinations. Traveling mobile robot will be challenged when there are plenty of travel options and obstacles; it is necessary for special methods to deal with this. Petri net modeling is one method that can be applied in this navigation. As a model network graph, Petri net can be seen as a model of superior visuals for their token moves that define the process dynamics of a system. Other models that have been provided, such as flow charts, block diagrams or network topology, are using the method of mathematical reachability. Meanwhile Petri net obtained the navigation as a result of marking the value. The final results of this research is that Petri net can be used to obtain mobile robot for navigation

Adriansyah, Andi

Gunardi, Yudhi

Hanafi, Dirman

Supegina, Fina

English

UTHM Institutional Repository

ICTLHE ● RCEE ● RHED2012 Java Programming Assessment Tool for Assignment Module in Moodle E-learning System  Norazah Yusof a *, Nur Ariffin Mohd Zin b, Noor Shyahira Adnan c  a,cFaculty of Computer Science and Information System, Universiti Teknologi Malaysia, Skudai, 81310 Johor, Malaysia bFaculty of Computer Science and Information Technology,Universiti Tun Hussien Onn Malaysia, 86400 Parit Raja, Johor, Malaysia    Abstract This paper proposes an intermediate system called JAssess which is developed to provide a solemn solution in providing a handy way to manage submission of students' Java programming exercises from MoodleTM, as well as grading them semi-automatically. This system implements dynamic testing type where testing involves executing of the program. This paper will explains in detail about the proposed system, JAssess, and the algorithm that lay behind it. It presents the major methods used while evaluating the Java programming assignment which include: the predefined Java File, Java Unzip, Java Runtime, Java Compiler and Java Reflection. Section 4 reviews the integration of JAssess with MoodleTM, in which it extends the functionality of the learning management system and provides better learning environment. It also explains on how to overcome the different environment used in JAssess and MoodleTM, in which MoodleTM is written in PHP, while JAssess is using Java technology. Although PHP and Java are not similar in terms of its syntax, but both are able to interact between each other with the help of data layout structure. A few test samples have been prepared in which they represent the successful and failed of the Java program compilation. Results are being discussed and are shown that the proposed model is able to display the suggested mark along with the output for every successful compilation, and will display the error along with the suggested mark for every failed compilation. Finally, some limitations of the proposed system and suggestions for future works section was concludes in this paper.  Keywords: programming assessment; Moodle TM; web-based; Java programming language; 1. Introduction  Learning programming languages, such as the Java object oriented programming language, is a great challenge especially when the students are still in the basic level of programming efficiency.  A lot of practical exercises are needed to help the students to lead to better understanding on a particular topic.  By giving appropriate programming exercises and assignments, the students' cognitive skill can be increased.  Unfortunately, lecturers take a lot of time and effort to evaluate and assess the students’ programming exercises and assignments.  The manual approaches of assessing programming assignment, such as the hardcopies and diskettes, are obviously costly, time consuming and inflexible.  Nowadays, learning management system (LMS) is widely used to provide learning supports to the lecturers and students, as well as administrative and technical support (Guido & Andreas, 2009). One of the most prominent LMS used today is MoodleTM (Cole & Foster, 2007).  Assignment module is among the most useful facility in MoodleTM that allows lecturer to set assignment with a due date and a maximum grade.  Within the specified date, the students are able to submit their assignments to the server.  The system records the date of when the students upload their programming files and this function allows lecturer to view any late submission.  The lecturer is then able to download the programming work and give grades and feedbacks.  Students are able to view the grades and feedback at any time and location. However, MoodleTM lacks of support in compiling and running the programming language  * Norazah Yusof. Tel.: +6-019-728-0505     E-mail address: norazah@utm.my  2assignments, specifically the Java programming language.  The lecturer needs to download each programming source files and save it in different locations in the lecturer's own personal computer.  The lecturer will then need to compile and run the program separately and then come back to MoodleTM to give marks and feedbacks.   The functionality of MoodleTM as the learning management system needs to be extended so that it can provide a handy way to evaluate students’ Java programming exercises.  Therefore, this paper reports about the proposed system named JAssess which is developed in Java platform.  It provides a seamless solution in providing a handy way to manage submission of students’ Java programming exercises, including compiling and running the programs, as well as giving marks and feedbacks. Within this system, the lecturers and students interact with the MoodleTM system to upload and download Java programming assignments.  The lecturers are able to evaluate the programs without the need to log out of the MoodleTM system. 2. Related works on programming assessment tools  The earliest automatic program grading tool was published by Hollingsworth (1960) which was used for a formal course in programming.  At that moment, old style key punched programming was still widely used. Since then, the use of automatic grader has been expanded widely in several programming languages until today.   TRY system was developed in late 80’s for Unix operating system which test student program with a set of hidden test data (Reek, 1989). By keeping the test data hidden, students are encouraged to design programs without any advance knowledge of the test cases.    Web-CAT, an open source automated grading system, grades the student codes and students' assignment for each submission by writing their own test code (Edwards and Pérez-Quiñones, 2008). This approach helps the students to understand better of their own work by having the sense of responsibility to prove the correctness and validity of their program. But as far as we concern, a fully automated grader that performs the entire task would be very much convenient without having a single effort. 3. Overview of the proposed system  MoodleTM, an acronym for Modular Object-Oriented Dynamic Learning Environment, is an open source software written in PHP language, which is designed to help both lecturers and students the opportunity to interact each other through online course ( Cole & Foster, 2007).  MoodleTM provides many modules for various teaching and learning activities, such as the resource module, assignment module, discussion forums, and quiz module (Kumar et. al., 2011).  One important characteristics of MoodleTM is that it allows modification made to the original copy of the source code provided that the developer should not modify or remove the original license. This characteristic makes it possible to extend the functionalities of MoodleTM so that it can meet certain organization needs.  JAssess, an acronym for Java Assessment tool, is the interface to compile and run Java programming source files to produce appropriate output.  This tool is  written in Java language.  The lecturer may adjusted the marks suggested by the system and give feedback to the students appropriately.    Figure 1 shows the Moodle (in PHP platform) and JAssess (in Java platform) in which both are web-based systems and supported by the MySql database.  Although PHP and Java are not similar in their syntax and semantics, we are able to connect them together through the intermediate controller (named JAssessMoodle) that can interact between the two technologies.            FiassigndatesFigurAprepawriteruntimSuHoweThe nfollowstoredNenvirassignJAssethe sprogredit tMark   gure 2 illustrment’s descri and more impe 3.  fter posted thring the answe Java source fie error.  bmission of tver, before suame of the zi the syntax o in the databaext, is the evonment, includment, the lecssMoodle.  Thuccessful comam.  For the uhe code.  The ' area, as well MAuthor ates the flowption and taskortantly the me task to the ar by writing Jle. 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Once  uon date and ase to view all  source file, ais action direcurce files willof the program see the code and the lectureea. sess system  (2012) 000–000  ss starts by o specify the asful and failedto view the a text editor suo make sure thrce files throuess their java pconsists of theploaded the cosignment’s dessubmitted assnd time of suts the system  be displayed a and the souto identify ther may changeMthe lecturer dssignment nam compilation assignment taskch as Textpadat there is nogh Moodle enrograms into  main methodmpressed .zipcription. ignments in tbmission.  Toto the JAssesss shown in Firce code of t possible reaso the marks at toodleTM system  efining the e, the due s shown in s and start , is used to  syntax and vironment. .zip format.  . This is to  file will be he Moodle  assess the  system via gure 4.  For he original n and may he 'Change   4       Figure 3. Lecturer setting the assignment tasks     Figure 4. Lecturer setting the assignment tasks  4. JAssess assessment algorithm   The predefined Java File, Java Unzip, Java Runtime, Java Compiler dan Java Reflection play a big role in making the assessment succesful (Truong et. al., 2004).  The first step in the assessment process is to create a folder at the server with the name of the student’s matric number. Inside this folder, a subfolder with the assignment’s name is created. This subfolder contains the compressed zip file. These processes require Java File class and therefore the File class from package java.io.File should be imported to ensure these processes possible.  successful program suggested mark Lecturer feedback  Author name / Procedia – Social and Behavioral Sciences 00 (2012) 000–000   5 Before any process could be proceeded, the class should be initiated as example below.   File f = new File("C:\\student");  Based on the example, an instance f is declared which assigned to the location and the name of the file/folder. At this point, we can perform several tasks by using predefined methods. To indicate whether the location assigned is a directory or a file, we can use isDirectory()or isFile() method, respectively. To determine whether a file exist or not, the method exists() should be used. The method returns a true if the file/folder is exists or false if the file is not exists. If the folder location defined is not exists, we can use method mkdirs() to create the folder. On certain condition, we need to list out all the files in the student’s folder, and that’s when we invoke the method listFiles(). Method delete() erases a folder by returning a true value if the folder successfully deleted and false value, otherwise. One of the requirements that the student should follow prior to the submission of the Java source files is to compress all source files into a single file using the .zip format.  Thus, during the second assessment process, the decompression process of the zipped files needs to be performed before the compilation process.  The java.util.zip package provides features for data compression and decompression in ZIP and GZIP formats. This package provides a ZipInputStream class for reading the ZIP files. Once a ZIP input stream is opened, we read the zip entries using the getNextEntry() method which returns a ZipEntry object. The set up of the decompressed output stream is specified as follows.    int BUFFER = 2048; FileOutputStream fos = new FileOutputStream(entry.getName()); BufferedOutputStream dest = new BufferedOutputStream(fos, BUFFER);  Third, in order to compile the Java program, a file named Compile.class need to be copied to the student’s subfolder. This file contains algorithm that applies the Java Compiler as a mean to compile student’s Java program.  The command prompt application needs to be executed in order to compile the student’s source code and run them. The tricky part is to run the command prompt within JAssess, which means it has to be triggered automatically by a command in the source code. This is done by employing Runtime class from package and calling exec() method as shown below.  Runtime rt = Runtime.getRuntime(); Process pr = rt.exec("cmd /c dir");  The fourth step is the Java Compiler from javax.tools package as shown below.  At this stage, the compilation is done within the source code and without employing the javac command.  Once successful, a byte code file is being generated that is known as a class file.    JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();  If unsuccessful, error message is displayed.  Java Reflection provides a dynamic way to manipulate object at runtime. It has the ability to examine or modify the runtime behavior of applications running in the Java virtual machine. By narrowing the usage of this class, it is used to assess the main method of the student’s program. This task could be done by importing the java.lang.reflect.Method package. Inside the Method class, resides a function named invoke() which is used to run any method in a class.       6The example below shows the use of Java Reflection to run a Java program called Hello.java.   Class a = Class.forName("Hello");  Method m = a. getDeclaredMethod("main", new Class[] {String[].class });  In the above code, the Java program is declared by the forname() method and the main() method accessed by the getDeclaredMethod() method. Once the main() method is accessed, the invoke() method is called as follows.   m.invoke(null, new Object[] { null }); 5. Results and Discussion We have conducted several tests by preparing a set of test cases. The test cases represent sample programs that are based on the assignment questions. Each cases purposely prepared for any of these two conditions: successful compilation and unsuccessful compilation.  With the proposed system, the lecturer found out that the students' programs can be graded in ease. Lecturers just need to click on the ‘Grade’ button under the JAssess column and the system will display the compilation results. For every successful compilation, it displays the output with the suggested high marks. However, if a compilation failed, it will display the error along with the suggested low marks.  Lecturers are able to view each of the source code submitted by the students. Hence, for unsuccessful compilation cases, they can track for errors and manually correct it until the programs are error free and ready to be run.. Conclusions and future work JAssess is a web based system that grades student’s Java program based on successful or failed compilation. This system implements the predefined packages of Java File, Java Unzip, Java Runtime, Java Compiler dan Java Reflection to complete a full process of assessment. Each packages assigned their own roles and together, it helps to reduce the workloads faced by educators each semester.  Moodle is a learning management system that creates opportunities for educators and students for interaction for teaching and learning activities. Regardless of features of an e-learning platform, we didn’t find any grading tools that fit to assess a Java program. As a result, integrating between Moodle and JAssess would be a perfect match as it will complements each other.  Although the integration is a successful attempt, it still has drawbacks. One limitation is that the marks is given based on successful compilation and does not aware of the logic errors.  Students may receive high marks if they submit any error free Java program even though the program do not meet the criteria of the question.  Therefore, the lecturers still need to view the output and verify the correctness of the program, which makes this system obviously semi-automated. For future research, the assessment process may be improved; from compilation based to logical based. Acknowledgements We are grateful to the Center of Teaching and Learning, Universiti Teknologi Malaysia for supporting the work in this field with the Research Grant Vot. No. Q.J130000.2528.01H82.     Author name / Procedia – Social and Behavioral Sciences 00 (2012) 000–000   7References Cole, J. and Foster, H. (2007). Using Moodle: Teaching with the Popular Open Source Course Management System, O'Reilly Media, Inc. Edwards, S. H. and Pérez-Quiñones, M. A. (2008). Web-CAT: Automatically Grading Programming Assignments.  ITiCSE’08, June 30–July 2, Madrid, Spain Guido, R. and Andreas, K. (2009). Extending Moodle To Better Support Computing Education. Proceedings of the 14th Annual ACM SIGCSE Conference on Innovation and Technology in Computer Science Education, Paris, France, p. 146-150, ACM Press, New York. Hollingsworth, J. (1960). Automatic Graders for Programming Classes. Communication of ACM Vol 3, Issue 10, pp. 528-529. Kumar S.,  Gankotiya A. K. and  Dutta, K. (2011). A comparative study of Moodle with other e-learning systems, 3rd International Conference on Electronics Computer Technology (ICECT) Reek, K.A. (1989). The TRY System – or – How to Avoid Testing Student Programs. Proceedings SIGCSE Bulletin vol.21, 1 (February 1989), pp. 112-116. Truong, N., Roe, P. and Bancroft, P. (2004). Static Analysis of Students' Java Programs. Sixth Australasian Computing Education Conference (ACE2004), Dunedin, New Zealand.    

Mathematics base for navigation mobile robot using reachability petri net

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