INSTRUCTIONAL TESTING THROUGH WIRELESS HANDHELD DEVICES

Transcription

1 INSTRUCTIONAL TESTING THROUGH WIRELESS HANDHELD DEVICES Cerise Wuthrich 1, Ranette Halverson 2, Terry W. Griffin 3, Nelson L. Passos 4 Abstract - In the educational field, students and faculty are looking for tools that may help to improve the learning process. Today s students, however, are usually too busy to follow a plan of study. Practice tests and questions are becoming an essential requirement of textbooks to allow the students to evaluate their current knowledge. Wireless access to the Internet has opened the door to a new range of computer applications, designed to satisfy the requirement of mobile users, equipped with a cell phone device. This paper describes the use of mobile devices as a medium for a self-evaluation tool complete with study guidelines feedback. Such an application is designed and implemented using many traditional Web methodologies, allowing a fast transition from the current wired Web system to the cell phone environment. This paper briefly discusses the Web tools used in such an implementation and presents an example of a test-feedback application appropriate for cell phone access.. Index Terms Wireless web, Cell phone, On-line testing, Distance education. INTRODUCTION Cell phones and personal digital assistants are becoming easier to use, more affordable, and continue to offer a wider range of services. While 1 st generation cell phones were analog devices capable of voice communications only, 2 nd generation and beyond also have data communication capabilities. 2G cellular systems use Time Division Multiple Access transmission technology and offer data communication services that are circuit-switched and operate at very low speeds. 3G systems will offer packetswitched services operating at higher rates of speed, which will support a wide range of multimedia services [6]. While 3G systems will use Code Division Multiple Access and provide data rates up to 2 Mb/s, 4G mobile networks will consist of potentially billions of mobile nodes [10] and support data rates up to 20 Mb/s [7]. With the increasing popularity of mobile wireless devices, countless new applications will be enabled [15]. Among these new applications, this paper proposes a method for quickly testing and reviewing over specific study content area. Educational institutions currently provide many online services to students within traditional wired networks. In an effort to extend Internet technologies to wireless networks, bearers, and devices, the Wireless Application Protocol (WAP) forum was established in WAP is a consortium of industry leaders such as Ericcson, Motorola, and Nokia, who designed an architecture for delivering advanced data services to mobile users with wireless devices. WAP specifications define a set of protocols and standards for applications, transactions, security, and transport in mobile wireless networks. The current version of the Wireless Application Protocol is version 2.0, which was released by the WAP forum in January 2002 [17]. Also, a Wireless Application Environment is defined which provides for interaction between WAP applications and wireless devices containing a WAP microbrowser. Such standards are the conceptual basis for the application described in this paper. Concurrently with the WAP consortium creation and in response to the increasingly mobile campus community, several universities began offering wireless Web service to their students, allowing the retrieval of a wide range of information such as access to registration, class schedules, financial aid information, and grades, through wireless devices. A natural extension to those wireless services is the opportunity to provide feedback to the students regarding their weaknesses and strengths in some specific study topic. While a student is away from class, he or she could use his or her cell phone to access a database of multiple -choice questions covering the class material, evaluate their current knowledge and receive feedback in the form of study directions. With the use of a cell phone, the user would no longer be limited to a particular location. This paper presents the basic information necessary to develop such an application. Currently, in the field of education, there are various methods for online evaluation of the progress of students [5, 11], with a variety of companies offering their services for designing online testing. Additionally, faculty can customize and personalize testing procedures by creating databases of test questions and answers, writing scripts to access the database and present the questions, scoring the results and possibly providing feedback. This is possible not only with Web pages written in HyperText Markup 1 Cerise Wuthrich, Midwestern State University, Dept. of Computer Science, 3410 Taft Blvd, Wichita Falls, TX cerise.wuthrich@esc9.net 2 Ranette Halverson, Midwestern State University, Dept. of Computer Science, 3410 Taft Blvd, Wichita Falls, TX 76308, ranette.halverson@mwsu.edu 3 Terry W. Griffin, Midwestern St ate University, Dept. of Computer Science, 3410 Taft Blvd, Wichita Falls, TX 76308, terry.griffin@mwsu.edu 4 Nelson L. Passos, Midwestern State University, Dept. of Computer Science, 3410 Taft Blvd, Wichita Falls, TX 76308, nelson.passos@mwsu.edu S4E-7

2 Language (HTML), but also with WAP applications. By using mobile wireless devices that are much more affordable for students than desktop computers, there exists the potential for greater equity in education [2]. In order to develop applications for the wireless environment a new markup language was defined and named WML for Wireless Markup Language. This paper combines WML and other tools in the implementation of the test practicing application. Following is a more in-depth discussion of WAP applications, the WML language, a database server called MySQL, and the scripting language PHP (PHP Hypertext Preprocessor), which was used in the online testing environment. server, but instead is sent to a WAP gateway. The WAP gateway has the responsibility of changing the binary coded request into a standard Web request, using the Hypertext Transmission Protocol (HTTP). The new HTTP request is then sent to the Web server. The transmission of the WML response to the handheld device is similar to the requesting process. Upon reception of a request, the Web server transmits the required WML page to the WAP gateway, which then encodes the data into binary WML and sends back to the user agent. Figure 1 shows a diagram representing this process. BACKGROUND It is estimated that by the year 2004, approximately 1.3 billion wireless Internet users will have mobile wireless devices. By 2008, it is predicted that more people will access the Internet through WAP-enabled devices than conventional wired systems [8]. If a device is WAPenabled, it means that it has a microbrowser loaded into it that permits it to communicate with and handle WAP documents which are written in WML. WML is a subset of XML (Extensible Markup Language) and is a language comparable to HTML used to develop traditional Web pages. Published studies indicate that while in December of 1999, there were only about 10,000 pages on the Web that supported WML, by August of 2000, there were approximately 4 million demonstrating the fast expansion of the wireless market [4]. Applications designed for wireless mobile devices are usually slightly different from those used on desktop computers since they are required to satisfy limitations inherent to WAP-enabled devices, such as the limited size and resolution of their displays, their limited input capabilities, small bandwidth, access time, limited CPU capacity and the users ability to move in and out of coverage areas. Mobile device users are not expected to browse the Web for hours and hours. Instead, they will be looking for fast access to specific information. Successful WAP applications will have few graphics and require limited user input due to the restricted input capabilities of the keypad. While there are programs on the market, such as Argo ActiGate and Openwave Mobile Access Gateway [12, 16], which convert existing HTML code into WML, there are also formatting and user interactivity problems, which arise during the conversion process. Pure WML sites are, therefore, more desirable than those created by a conversion process. In order to deal with the low transmission speed, when the user agent (wireless mobile device) makes a request for a page from a Web server, the request is transformed into a compact, binary format that is well suited for quick transmission over the wireless link. In current implementations, the request is not sent directly to a Web FIGURE 1. COMMUNICATION BETWEEN USER AND SERVER The Web server mentioned in this context is the storage element where standard Web pages can be found. Those pages specifically designed for wireless devices, written in WML, can be stored on the same server. WML WML is a generalized tag-based markup language analogous to HTML. Most Web publishing has traditionally been done using HTML code to produce pages that can be viewed by a Web browser such as Internet Explorer [1]. While HTML files are referred to as pages, WML files consist of decks of cards. A card is basically equivalent to the information that can be displayed on a single screen of a mobile wireless device. Several cards can be combined into one document called a deck. It is desirable to place as many cards as possible in one deck since the WAP device will download an entire deck at a time. However, different manufacturers such as Ericsson, Nokia, and Openwave have developed different microbrowsers which have varying limitations on the size of a compiled WML deck, ranging from 1492 bytes to approximately 8000 bytes. Developers of WAP applications must keep these size limits in mind when designing the WML decks. WML is a stricter language than HTML in that all tags must be in lowercase and all loops must be nested correctly. It is more compact than HTML since it has only 35 tags compared to about 120 in HTML. WML supports the use of text and limited images, and provides the ability to interact with the user and navigate to other links [9]. All WML documents must include a prologue, which includes the S4E-8

3 XML version and a pointer to the XML document type definition. The prologue used in the testing application is shown in figure 2. Each deck, which is delimited with the <wml> tag, consists of at least one card, delimited with the <card> tag. An example of WML code for a single card and the corresponding output are shown in Figures 3 and 4. Similar pictorial results can be obtained by simulation using the Openwave SDK tools [13]. <?xml version="1.0"?> <!DOCTYPE wml PUBLIC "- //WAPFORUM//DTD WML 1.1//EN" " FIGURE 2. XML PROLOGUE <card title="msu"> <p align="center"> <b>msu Computer Science</b><br/> Home of the Indians <img localsrc="star2" src="./star2.wbmp" alt="star"/> <img localsrc="star2" src="./star2.wbmp" alt="star"/> <img localsrc="star2" src="./star2.wbmp" alt="star"/> </p> <p align="left"> <select> <option onpick = "#phone_numbers"> PhoneNumbers </option> <option onpick="#calendar"> Calendar Info</option> <option onpick="#faculty_pages"> Faculty Web Sites</option> </select> </p> </card> a scripting language to enable the Web pages or cards to communicate with the database. PHP The scripting language chosen for the testing application is PHP (PHP Hypertext Preprocessor), which is an open source and server-side scripting language. PHP is assumed to be the most popular Web application server [14]. Although there exists a scripting language, WML Script, which can be accessed from WML decks and is designed specifically for WAP applications, PHP was chosen for 2 reasons. First of all, server-side scripting means that the Web server, instead of the client, processes the PHP code and the browser shows the result of that processing. Since most WAP-enabled devices have a limited amount of processing power, PHP was a logical choice. In addition, PHP allows the introduction of dynamic content into the WAP application and interacts nicely with the database. PHP is a loosely typed language, which means that a single variable may contain any type of data (integer, text, etc.) and its type may change over the course of the code. FIGURE 3. WML CODE FOR A SINGLE CA RD MySQL FIGURE 4. SINGLE CARD OUTPUT In order to provide the WML user with access to a database of test questions, a database management system had to be chosen. While there is a wide variety of database software on the market, the application described in this paper uses the software known as MySQL, which is used to create, query, and manipulate the database. Such a system accepts commands written in a language known as Structured Query Language or SQL. SQL is currently one of the most popular database languages and, according to the American National Standards Institute, is the standard for relational database management systems. To implement a MySQL database, the user can work from the command line or use a visual interface. MySQL is open source software that is fast, stable, and free, although is has some licensing restrictions. Web Server Before writing code for the online testing WAP application, several characteristics of the Web server had to be considered. Since most of the existing Web servers in the Internet are based on the Apache software [3], this type of server was considered for the testing application. Apache is Web server software that is freely available, runs in most Unix/Linux systems, and is host to a huge number of HTML Web pages. However, the server must be set up to properly deliver WML decks to a wireless device, and recognize the type of the WML file, based on the file name extension. For most Apache servers, this can be easily accomplished by adding the lines shown in Figure 5 to the httpd.conf configuration file. It runs under a broad array of operating systems and requires S4E-9

4 APPLICATION DESIGN AND IMPLEMENTATION AddType text/vnd.wap.wml.wml AddType application/vnd.wap.wmlc.wmlc AddType text/vnd.wap.wmlscript.wmls AddType application/vnd.wap.wmlscriptc.wmlsc AddType image/vnd.wap.wbmp.wbmp FIGURE 5. WML CONFIGURATION COMMANDS Next, for this particular testing application, the Web server was required to have the MySQL software installed and running. This is necessary because the test questions and answers are stored in a MySQL database, located on the server. By placing all the necessary information in the MySQL database, that information can be accessed and viewed through HTML Web pages or WML decks, thus reducing redundant efforts. The Web server administrator is usually the responsible party for installation, set up, and activation of the MySQL database. Also, the server must be set up to support PHP. Once again, this can be enabled by pasting the code shown in Figure 6 into the configuration file of the Apache server: The implementation of the online testing application discussed in this paper involved several steps. First of all, a series of WML decks were written introducing the user to the school s home page and then linking to individual faculty member's pages. From a faculty Web page, the online testing application could be accessed through a hyperlink. Next, the MySQL database was created with tables containing all information about the tests including name of the test, objectives covered, questions, answer choices, and feedback responses. Then the WML code was written with a PHP script embedded into it connecting to the MySQL database and prompting the user to select which test to take. A portion of the experimental script along with the corresponding output on a generic cell phone is shown in Figures 7 and 8. AddType application/x-httpd-php3.php3 FIGURE 6. PHP CONFIGURATION COMMAND <wml> <card id="test1" title="choose Test"> <p align="center"> <b>select a Test </b> <br/> <?php $id_link 'root', 'password') or die ("Could not connect"); $db_link = mysql_select_db('test_center'); $query = "select * from test order by id"; $result $i = 0; if (mysql_num_rows($result) > 0) { while($row = mysql_fetch_array($result)) { $i++; echo"$i.<a href=\"take_test.php?id = $row[id]&qnum = 1\"> $row[title]</a><br/>";}} else { echo"no tests.";}?> </p> </card> </wml> FIGURE 7. WML CODE WITH EMBEDDED PHP SCRIPT FIGURE 8. WML OUTPUT According to the user s input, the PHP script accesses the appropriate test and displays a question along with answer choices. Selecting an answer actually appends the letter of the answer choice to a string variable and links to the PHP script again. This process continues until all questions have been answered. The script shown in Figures 9 and 10 displays questions and answer choices, and its equivalent display output. Once all questions have been answered, the student s score is calculated and appropriate feedback including remediation suggestions is displayed. An example of the output involving the scoring display of a simple 3-question practice test is shown in Figure 11. Notice that question number 2 was incorrectly answered and presented a pointer to the textbook where the corresponding topic is covered. Writing WML code is fairly simple and straightforward. The small screen size is a recurring consideration, so all text must be kept as concise as possible to avoid scrolling down the screen. For this application, the database was already in use by a faculty member who had S4E-10

5 written the PHP script to access the information that was then viewed from a standard HTML Web page. Only slight modifications had to be made to the script in order for the material to be viewable on a cell phone. <?php $next = $qnum+1; //Gives us the next question number $answer_list=$answer_list.$ans; //appending each new answer to a lists $query = "select * from test_questions where id=$id and qnum='$qnum'"; $qresult $row = mysql_fetch_array($qresult); if (mysql_num_rows($qresult) > 0){ echo"<b>question $qnum </b><br/>"; echo"$row[question]<br/>"; $query = "select * from test_choices where id='$id' and qnum='$qnum'"; $cresult FIGURE 9. QUESTION AND ANSWER CHOICES SCRIPT. FIGURE 10. QUESTION AND ANSWER OUTPUT. Testing of the code was done primarily with various cell phone simulators. Use of simulators made testing easy and affordable since no wireless charges were incurred. However, several problems were discovered when the project was tested with an actual cell phone. Entering the desired URL is simple with a simulator since the computer keyboard can be used. However, entering the URL from a cell phone for the first time can be a tedious and frustrating process. For example, to enter the URL cs.mwsu.edu/~wireless required 56 punches on the cell phone keypad. Entry of special characters such as the forward slash and tilde are complex and the cell phone user s guide was incorrect most of the time. Therefore, when planning a URL, the designer should keep it as short as possible and advise users to bookmark the site. FIGURE 11. FEEDBACK FROM TESTING APPLICATION Another problem not realized while assessing the project with a simulator was that most simulators allow WML decks of unlimited size to be downloaded. Only when testing the application with an actual cell phone was the importance of the size of downloaded decks realized. The cell phone used for the experiment runs a microbrowser that limits the size of compiled decks to 1492 bytes. To help with the implementation, most simulators allow the designer to examine the size of the compiled WAP binary code and design the application under more specific constraints. Furthermore, while using a simulator, it is possible to instruct the microbrowser to clear its cache. Thus any changes made to any WML decks will take effect the next time the simulator is used. However, in actuality, after a WML deck was downloaded to the experimental WAP device, it remained in the device s memory for a certain period of time. Thus, when the deck was subsequently retrieved, it was accessed from the device s cache instead of the server. For decks containing information that is updated frequently, this is not desirable. Preventing a deck from being loaded from the device's cache can be accomplished in one of two ways. Either header must be produced on the server side using a scripting language such as PHP or else meta tags can be included in the header portion of the WML document. The tags shown in Figure 12 specify how the cache will be controlled. The first tag prevents a deck from ever being cached while the second tag will allow a deck to be cached for a maximum of 24 hours. The last tag specifies that the deck will always be reloaded from the server when accessed. S4E-11

6 <meta forua = "true" http-equiv = "Cache-Control" content = "max-age = 0"/> <meta forua = "true" http-equiv = "Cache-Control" content = "max-age =86400"/> <meta forua = "true" http-equiv = "Cache-Control" content = FIGURE 12. META TAGS CONTROLLING CACHE OPERATION The success of the application developed under this study is still to be effectively measured. The current implementation has been tested by a group of students not involved with the target class in order to evaluate the functionality of the system. Although most cell phones are currently limited to a bandwidth of 19.2 Kb/s or less, the application ran fairly quickly. With the introduction of 3G systems, the application could be further expanded, including the potential to even push notification of new test content to the student on his/her cell phone. CONCLUSION With the multitude of wireless mobile devices and the advent of improved technologies, protocols, and standards, wireless access to the Internet will continue to increase. The Internet will truly become ubiquitous as wireless access becomes easier and users are no longer tethered to particular locations. In response, new WAP applications in various fields will subsequently emerge. Many applications, such as the one described in this paper, can be easily modified to run on wireless mobile devices rather than desktop computers. WAP applications will be different because of the restrictions of current WAP-enabled devices. A useful tool for the mobile college student, who is willing to use the device and sees a need for the service, is online testing and self-evaluation. While current online testing is done from traditional computers, the use of cell phones and personal digital assistants for the same purpose allows the student to access that application at any time and any place. This paper discussed the concepts, theories, methodologies, and practices important in implementing such an application. Central Conference, Journal of Computing in Small Colleges, Volume 14, Number 3, March 1999, pp [6] Guo, Y. and Chaskar, H., "Class-Based Quality of Service over Air Interfaces in 4G Mobile Networks," IEEE Communications, Volume 40, Number 3, March 2002, pp [7] Huang, V. and Zhuang, W., "QoS-Oriented Access Control for 4G Mobile Multimedia CDMA Communications," IEEE Communications, Volume 40, Number 3, March. 2002, pp [8] Lewis, T., UbiNet: The Ubiquitous Internet Will Be Wireless, Computer, Volume 32, Number 10, October 1999, pp [9] Mann, S., Programming Applications with the Wireless Application Protocol, John Wiley & Sons, New York, NY, [10] Misra, A., Das, S. and Das, S. K., IDMP-Based Fast Handoffs and Paging in IP -Based 4G Mobile Networks, IEEE Communications, Volume 40, Number 3, March 2002, pp [11] Naik, B., Enhanced Course Delivery using the Web, in the Proceedings of the Sixth Annual CCSC Central Plains Conference, Journal of Computing in Small Colleges, Volume 15, Number 4, April, 2000, pp [12] Openwave Mobile Access Gateway Edition, Openwave Systems, Inc., Redwood City, CA, February 2002, pub. DSMAG-R [13] Openwave SDK WAP Edition 5.0, Openwave Systems, Inc., Redwood City, CA, September, 2001, pub. DSSDK-R [14] Royappa, A., The PHP Web Application Server, in the Proceedings of the Eleventh Annual CCSC South Central Conference, Journal of Computing in Small Colleges, Volume 15, Number 3, March 2000, pp [15] Shotsberger, P. and Vetter, R., The Handheld Web: How Mobile Wireless Technologies will change Web-based Instruction and Training, Educational Technology, October 2000, pp [16] WAP Deployment Fact Sheet, WAP Forum, February [17] Wireless Application Protocol WAP 2.0. Technical White Paper, WAP Forum, January ACKNOWLEDGMENT This work was partially supported by the Texas Advanced Research Program under Grant No b REFERENCES [1] Castro, E., HTML for the World Wide Web, 4 th Ed., Peachpit Press, Berkeley, CA, [2] Fulton, K. and Honey, M., Emerging Technologies in Education, Educational Technology, July 2002, pp [3] Gagne, M., Linux System Administration, Addison Wesley, Boston, MA, [4] Gillot, I., Exploding Myths about WAP, Analyst Corner, November 27, [5] Giraldo, J. H., Enhancing the Learning of Mathematics through the Web, in the Proceedings of the Tenth Annual CCSC South S4E-12