Internet-assisted Real-time Experiments Using the Internet Hardware and Software Considerations R. Paul Singh and Diego Circelli

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1 Classroom Techniques... Internet-assisted Real-time Experiments Using the Internet Hardware and Software Considerations R. Paul Singh and Diego Circelli ABSTRACT: The spectacular increase in Internet-based applications during the past decade has had a significant impact on the education delivery paradigms. The user interactivity aspect of the Internet has provided new opportunities to instructors to incorporate its use in developing new learning systems. The use of the Internet in carrying out live experiments has been a subject of interest that shows considerable promise. Using the common Internet browsers, it has become possible to develop engaging laboratory exercises that allow the user to operate experimental equipment from remote locations. To increase the availability of such experiments on the Internet, it would be beneficial to share methods employed in developing software and hardware of Internet-assisted experiments... among interested instructors. The objective of this paper is to present a description of the hardware and software required to create Internet-assisted laboratories. Introduction There has been a dramatic increase in the use of the Internet in education as witnessed in many countries around the world (NAS 1997; NASULGC 1997; NSF 1996). While the Internet has been most effective in providing easy access to educational resources, its use for other dynamic applications continues to grow. In this regard, our research group has been developing Internet-assisted laboratory exercises that provide remote access to real-time experiments for students (Singh 1996a; Ogot et al., 2003, Ewald and Page, 2000; Singh and Courtois 1999). At present, 4 such experiments have been developed in our laboratory to illustrate topics in food and biological engineering. These experiments are (1) measurement of psychrometric properties of heated air for food drying applications, (2) measurement of time constant of temperature sensors, (3) determination of convective heat transfer coefficient of air, and (4) image analysis of biological materials. The use of remotely conducted experiments has been attempted in the following 3 modes. As a pre-experiment exercise, students are asked to conduct a given experiment prior to coming to the laboratory. Having conducted an Internet-assisted hands-on experiment, the students are better prepared to discuss related topics with the instructor. Follow-up experiments may then be conducted with related equipment. The advantage of this approach is that every student participates in a hands-on experience despite the class size. It is not uncommon in laboratory classes with large enrollments for only a few students in a group to actively participate in all given tasks; several remain passive observers. By requiring each student to conduct an Internet-assisted experiment prior to attending a laboratory, each student is better prepared to later work in a group and conduct additional measurements to enhance learning experience (Rizvi and Mittal 1992). As a stand-alone exercise, students are able to conduct experiments when facilities at their respective institutions are not available. This mode has been used in having students from institutions in Argentina and Mexico access experiments in our laboratory in Davis, Calif., U.S.A. The 3rd mode is for lecture-only classes. Typically, in such classes homework assignments are given that are created with hypothetical data (Singh and Heldman 2001; Singh 1996b). By incorporating Internet-assisted experiments... in those assignments, students obtain real data and use it in problem solving, thus gaining further insights. The hardware for each experiment is connected via an analog-to-digital system, Opto 22 (Opto 22, Temecula, Calif. U.S.A.), to a desktop PC computer, which is used as a server. For the server, we have chosen Linux for its cost-effectiveness (available free at present) and high reliability. The software is custom written for flexibility and low cost. The objective of this paper is to provide details of software and hardware required to create Internet-assisted experiments.... While the specific equipments required for setting up an experiment are unique, the hardware required for connecting the equipment to the Internet has common features. These requirements will be discussed in the following sections. MS Submitted 2/9/04, Revised 3/4/04, Accepted 11/15/04. Authors are with Biological & Agricultural Engineering, Univ. of California, Davis, Calif. Direct inquiries to author R. Paul Singh, Depart. of Biological and Agricultural Engineering, Univ. of California, Davis, CA ( rpsingh@ucdavis.edu). 10 JOURNAL OF FOOD SCIENCE EDUCATION Vol. 1, Institute of Food Technologists

2 Internet-assisted experiments... System description Hardware setup The setup used consists of a PC server that runs all the needed software for both data acquisition and client handling. The server has 2 network connections: the 1st connects it to the Internet, and the 2nd connects it to the acquisition devices (Opto 22 Snap Ethernet I/O) and cameras (Axis 2100 or any FTP transfer capable network camera) used in the different experiment benches (see Figure 1). The use of different network interfaces isolates the acquisition devices and cameras from the Internet, thereby avoiding the risk of direct attacks to those devices. The use of network capable acquisition devices and cameras allows us to connect an arbitrary number of such devices, and therefore, to handle as many experimental benches as needed. The system is also capable of handling BBElectronics (Ottawa, Ill., U.S.A.) acquisition devices. Although the serial communication system of these devices Figure 1 Hardware setup limits the number of sensors than can be connected to the server, their low cost makes them an attractive alternative in some cases. (1) WWW server: an off-the-shelf Apache web server is used to handle all client requests. The use of a robust web server as the only point of connection for the clients helps secure the system from attacks. Also, by using standard HTTP for client-server communication, we enable the system to work easily across firewalls Figure 3 Main configuration file excerpt Software setup Linux was selected as the operating system for the PC server for its cost-effectiveness and high reliability. Three server applications run on top of this operating system (see Figure 2): Figure 2 Software setup Figure 4 Bench configuration file excerpt Vol. 1, 2005 JOURNAL OF FOOD SCIENCE EDUCATION 11

3 or network address translation devices. (2) FTP server: an off-the-shelf FTP server is used for the cameras to transfer all image files to the server. (3) Labserver software: this application developed at the Dept. of Biological and Agricultural Engineering at UC Davis is responsible for sampling and controlling the different sensors and actuators connected to the acquisition devices, validating user access to the system and keeping track of all session information for the different users. It was designed to read the description of the different experiments from simple text files, allowing for experiments to be added, deleted, or modified easily, with minimal impact on users activities and little effort for the experiment designer. The next section explains how this is done. Software configuration The server can be configured to control several different types of experiments. Figure 3 shows an excerpt of the main configuration file for the Labserver software. The 1st 3 lines list the directory where all web files should be placed, the log file name, and the user information file name. Following that, the configuration information for the experiments is detailed. In the excerpt, the information for the experiment Sensor dynamics is given. Some of the options are (1) fulltitle indicates the title to use on the web pages referring to this experiment. (2) and contactname parameters are used on the web pages where contact information is given. (3) samplingfactor indicates the sampling period as a multiple of 500 ms. (4) sessionlength parameter indicates the maximum number of seconds a user is allowed to lock the experiment for his or her use. (5) guestuserallowed indicates whether the guest user is allowed for the experiment. A guest user does not require a password to access the system and can only watch the sensor readings and images (that is, a guest cannot control the system). Then the different benches are listed, and their configuration file is given. The main configuration options for the experiment benches (see Figure 4) are: (1) picturedir indicates the path were the images for this particular bench are stored, and (2) devicetype and deviceaddress indicate which acquisition device is to be used. Next, input/output connections are listed giving their type (ana- Figure 5 Java interface 12 JOURNAL OF FOOD SCIENCE EDUCATION Vol. 1, 2005

4 Internet-assisted experiments... log or digital, and input or output) and name. For each input the connection point identifier ( channel ) must be given. Optionally, if a calibration curve or formula needs to be used to present corrected measurements to the user, they can be indicated using the calibrationcurve and function parameters respectively. The number of decimal digits can also be indicated. For each output the same parameters may be used, and some additional ones are required to configure the way the java interface will behave. The controltype parameter indicates whether a slider, textbox, checkbox, or combobox should be used. Minimum and maximum admissible values may be indicated, as well as the initial values to which outputs should be set when a user starts to work with the experiment, and the ones to which outputs should be set when the user stops working. Client description The users navigate the different experiments through a collection of web pages. Two different client interfaces were developed. Both of them were designed to be used from standard web browsers, such as Netscape or Internet Explorer, to place as few restrictions as possible on the type of machine or operating system that the student may be using. The 1st interface consists of a Java-based applet, which can display different information and controls, depending on the type of experiment being used (a slider and a combo box in the example shown in Figure 5). All of these are displayed in a compact, convenient format in order for the student to be able to easily understand the experiment status and carry out the actions he or she wishes. It has 3 different areas: a picture area where a live picture of the experiment bench is displayed, a controls area where the student sets the different system actuators, and a sensors area where current measurements of the different sensors and past values are graphed (see Figure 5). The 2nd interface consists of a collection of web pages that allows the user to have a similar experience to that of the 1st interface, except for the historical graph of the sensor measurements (see Figure 6). This 2nd interface does not require the Java plug-in (SUN Java Plug-in 1.4 or newer) to be installed in the client s machine, and therefore, allows slow computers to run more smoothly. It also can be convenient for computers with slow Internet connections, which do not have the java plugin installed and require waiting for the plug-in to download. Figure 6 HTML interface User Procedure The student begins by connecting to the URL address of the laboratory Web site using the browser of his or her choice. The 1st screen (see Figure 7) presents the student with a list of the experiments available. After choosing the experiment to carry out, the next screen (see Figure 7 Start screen Vol. 1, 2005 JOURNAL OF FOOD SCIENCE EDUCATION 13

5 Figure 8) requests a user login and password. If the student does not have a login and password, guest access may be available, providing a view-only access to the system. Once the student has logged in, the screen will show something similar to Figure 5. The user can choose the appropriate settings for the experiment by using the different controls provided and pressing the Commit button once all the values are set. The system receives updated values every second, and the information is displayed on the bottom part of the screen. There is a link ( HELP button) for the student to open an HTML file that describes the concepts important to the experiment. There is also a link to the instructor s address. If a student has chosen the HTML interface, a screen will be seen similar to the one shown in Figure 6, which automatically reloads with updated information every 5 s. To change the different settings, the student must click on the Click to set the conditions link, and a new screen will load where he or she may enter the desired settings. After doing so, the main screen returns with the updated image and sensor readings. After logging off from the experiment, the last screen thanks the student, and a set of questions are asked for feedback regarding Figure 8 Login screena the experiment. The student is also given the option to download the collected data for further analysis or have it ed to his or her account. The above-described setup has been regularly used in laboratory courses taught at the Univ. of California, Davis. Furthermore, instructors and students from other institutions in the U.S. and overseas (Argentina, Japan, France, New Zealand, and Mexico) have used this setup to conduct experiments (Palou et al. 2005). The hardware and software requirements, as presented in this paper, should provide the necessary background to develop new experiments that are remotely controlled on the Internet. Availability of such experiments will provide a major educational resource in food science for instructors and students to share the learning experience on a worldwide basis. References Ewald, H adn Page G Performing experiements by remote control using the Internet. Global Journal of Engineering Education. 4(3): Farkas BE Personal communication. North Carolina State Univ., Raleigh, NC. [NAS] Natl. Academy of Sciences Preparing for the 21st century: The education imperative. Washington D.C.: Natl. Academy of Sciences. [NASULGC] Natl. Assn. of State Universities and Land-Grant Colleges Returning to our roots: The student experience, A Kellogg Commission Report. Washington D.C.: Natl. Assn. of State Universities and Land- Grant Colleges. Kellogg/Kellogg2000_StudentExp.pdf [NSF] Natl. Science Foundation Shaping the future: New expectations for undergraduate education in science, mathematics, engineering and technology. Washington D.C.: Natl. Science Foundation. Ogot M, Elliott G, Glumac E An assessment of in-person and remotely operated laboratories. Journal of Engineering Education. p Palou E, Welti-Chanes J, Singh RP, Lopez-Malo A, Guerrero LG, Carrillo J, Ramirez JM, Athmaram K Remote Experiments for Food Engineering. Journal of Food Engineering 67: Rizvi SSH, Mittal GS Experimental Methods in Food Engineering, New York: Van Nostrand Reinhold. 289 p. Singh RP. 1996a. Teaching Food Science and Technology on the World Wide Web. Food Technology 50(3):94, Singh RP. 1996b. Computer Applications in Food Technology: Use of Spreadsheets in graphical, statistical and Process analysis. San Diego, Calif.: Academic Press. 300 p. Singh RP, Courtois F Conducting Laboratory Experiments via the Internet. Food Technology 53(9):54 6, Singh RP, Heldman DR Introduction to Food Engineering. London: Academic Press, 3rd Ed. 659 p. 14 JOURNAL OF FOOD SCIENCE EDUCATION Vol. 1, 2005