10 JOURNAL OF FOOD SCIENCE EDUCATION—Vol. 1, 2005 © 2005 Institute of Food Technologists

JFSE: Journal of Food Science Education

Classroom Techniques........

Internet-assisted Real-time ExperimentsUsing the Internet—Hardware and

Software ConsiderationsR. Paul Singh and Diego Circelli

ABSTRACT: The spectacular increase in In-ternet-based applications during the pastdecade has had a significant impact on theeducation delivery paradigms. The user in-teractivity aspect of the Internet has pro-vided new opportunities to instructors to in-corporate its use in developing new learn-ing systems. The use of the Internet in car-rying out live experiments has been a sub-ject of interest that shows considerablepromise. Using the common Internet brows-ers, it has become possible to develop en-gaging laboratory exercises that allow theuser to operate experimental equipmentfrom remote locations. To increase theavailability of such experiments on the In-ternet, it would be beneficial to sharemethods employed in developing softwareand hardware of Internet-assisted experi-ments . . . among interested instructors.The objective of this paper is to present adescription of the hardware and softwarerequired to create Internet-assisted labora-tories.

IntroductionThere has been a dramatic increase in the use of the Internet in education as wit-

nessed in many countries around the world (NAS 1997; NASULGC 1997; NSF1996). While the Internet has been most effective in providing easy access to edu-cational resources, its use for other dynamic applications continues to grow. In thisregard, our research group has been developing Internet-assisted laboratory exer-cises that provide remote access to real-time experiments for students (Singh1996a; Ogot et al., 2003, Ewald and Page, 2000; Singh and Courtois 1999). Atpresent, 4 such experiments have been developed in our laboratory to illustratetopics in food and biological engineering. These experiments are (1) measurementof psychrometric properties of heated air for food drying applications, (2) measure-ment of time constant of temperature sensors, (3) determination of convective heattransfer coefficient of air, and (4) image analysis of biological materials.

The use of remotely conducted experiments has been attempted in the following3 modes. As a pre-experiment exercise, students are asked to conduct a given ex-periment prior to coming to the laboratory. Having conducted an Internet-assisted“hands-on” experiment, the students are better prepared to discuss related topicswith the instructor. Follow-up experiments may then be conducted with relatedequipment. The advantage of this approach is that every student participates in ahands-on experience despite the class size. It is not uncommon in laboratory class-es with large enrollments for only a few students in a group to actively participate inall given tasks; several remain passive observers. By requiring each student to con-duct an Internet-assisted experiment prior to attending a laboratory, each student isbetter prepared to later work in a group and conduct additional measurements toenhance learning experience (Rizvi and Mittal 1992). As a stand-alone exercise,students are able to conduct experiments when facilities at their respective institu-tions are not available. This mode has been used in having students from institu-tions in Argentina and Mexico access experiments in our laboratory in Davis, Ca-lif., U.S.A. The 3rd mode is for lecture-only classes. Typically, in such classes home-work assignments are given that are created with hypothetical data (Singh andHeldman 2001; Singh 1996b). By incorporating Internet-assisted experiments . . .in those assignments, students obtain real data and use it in problem solving, thusgaining 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 isused 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 flex-ibility and low cost.

The objective of this paper is to provide details of software and hardware re-quired to create Internet-assisted experiments . . . . While the specific equipmentsrequired for setting up an experiment are unique, the hardware required for con-necting the equipment to the Internet has common features. These requirementswill be discussed in the following sections.

MS 20040075 Submitted 2/9/04, Revised 3/4/04, Accepted 11/15/04. Authors are with Biolog-ical & Agricultural Engineering, Univ. of California, Davis, Calif. Direct inquiries to author R. PaulSingh, Depart. of Biological and Agricultural Engineering, Univ. of California, Davis, CA 95616.(Email: rpsingh@ucdavis.edu).

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Internet-assisted experiments . . .

System description

Hardware setupThe setup used consists of a PC server that runs all the needed

software for both data acquisition and client handling. The serverhas 2 network connections: the 1st connects it to the Internet, andthe 2nd connects it to the acquisition devices (Opto 22 Snap Ether-net I/O) and cameras (Axis 2100 or any FTP transfer capable net-work camera) used in the different experiment benches (see Figure1). The use of differentnetwork interfaces iso-lates the acquisition de-vices and cameras fromthe Internet, therebyavoiding the risk of directattacks to those devices.The use of network capa-ble acquisition devicesand cameras allows us toconnect an arbitrarynumber of such devices,and therefore, to handleas many experimentalbenches as needed.

The system is also ca-pable of handlingBBElectronics (Ottawa,Ill., U.S.A.) acquisitiondevices. Although theserial communicationsystem of these deviceslimits the number of sensors than can be connected to the server,their low cost makes them an attractive alternative in some cases.

Software setupLinux was selected as the operating system for the PC server for

its cost-effectiveness and high reliability. Three server applicationsrun on top of this operating system (see Figure 2):

(1) WWW server: an off-the-shelf Apache web server is used tohandle all client requests. The use of a robust web server as theonly point of connection for the clients helps secure the systemfrom attacks. Also, by using standard HTTP for client-server com-munication, we enable the system to work easily across firewalls

Figure 1—Hardware setup

Figure 2—Software setup Figure 4—Bench configuration file excerpt

Figure 3—Main configuration file excerpt

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JFSE: Journal of Food Science Education

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or network address translation devices.(2) FTP server: an off-the-shelf FTP server is used for the camerasto transfer all image files to the server.(3) Labserver software: this application developed at the Dept. ofBiological and Agricultural Engineering at UC Davis is responsiblefor sampling and controlling the different sensors and actuatorsconnected to the acquisition devices, validating user access to thesystem and keeping track of all session information for the differ-ent users. It was designed to read the description of the differentexperiments from simple text files, allowing for experiments to beadded, deleted, or modified easily, with minimal impact on users’activities and little effort for the experiment designer. The next sec-tion explains how this is done.

Software configurationThe server can be configured to control several different types

of experiments. Figure 3 shows an excerpt of the main configura-tion file for the Labserver software. The 1st 3 lines list the directorywhere all web files should be placed, the log file name, and theuser information file name. Following that, the configuration infor-mation for the experiments is detailed. In the excerpt, the informa-tion for the experiment “Sensor dynamics” is given. Some of the

options are(1) fullTitle indicates the title to use on the web pages referring tothis experiment.(2) email and contactName parameters are used on the web pageswhere contact information is given.(3) samplingFactor indicates the sampling period as a multiple of500 ms.(4) sessionLength parameter indicates the maximum number ofseconds a user is allowed to lock the experiment for his or heruse.(5) guestUserAllowed indicates whether the guest user is allowedfor the experiment. A guest user does not require a password toaccess the system and can only watch the sensor readings andimages (that is, a guest cannot control the system).

Then the different benches are listed, and their configuration fileis given.

The main configuration options for the experiment benches(see Figure 4) are:(1) pictureDir indicates the path were the images for this particularbench are stored, and (2) deviceType and deviceAddress indicatewhich acquisition device is to be used.

Next, input/output connections are listed giving their type (ana-

Figure 5—Javainterface

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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 cali-bration curve or formula needs to be used topresent corrected measurements to the user,they can be indicated using the “calibra-tionCurve” and “function” parameters respec-tively. The number of decimal digits can alsobe indicated. For each output the same param-eters may be used, and some additional onesare required to configure the way the java inter-face will behave. The “controlType” parameterindicates whether a slider, textbox, checkbox,or combobox should be used. Minimum andmaximum admissible values may be indicated,as well as the initial values to which outputsshould be set when a user starts to work withthe experiment, and the ones to which outputsshould be set when the user stops working.

Client descriptionThe users navigate the different experiments

through a collection of web pages. Two differ-ent client interfaces were developed. Both ofthem were designed to be used from standardweb browsers, such as Netscape or Internet Ex-plorer, to place as few restrictions as possibleon the type of machine or operating systemthat the student may be using.

The 1st interface consists of a Java-based ap-plet, which can display different informationand controls, depending on the type of experi-ment being used (a slider and a combo box inthe example shown in Figure 5). All of theseare displayed in a compact, convenient formatin order for the student to be able to easily un-derstand the experiment status and carry outthe actions he or she wishes. It has 3 differentareas: a picture area where a live picture of theexperiment bench is displayed, a controls areawhere the student sets the different system ac-tuators, and a sensors area where current mea-surements of the different sensors and past val-ues are graphed (see Figure 5).

The 2nd interface consists of a collection ofweb pages that allows the user to have a simi-lar experience to that of the 1st interface, ex-cept for the historical graph of the sensor mea-surements (see Figure 6). This 2nd interfacedoes not require the Java plug-in (SUN JavaPlug-in 1.4 or newer) to be installed in the cli-ent’s machine, and therefore, allows slow com-puters to run more smoothly. It also can beconvenient for computers with slow Internetconnections, which do not have the java plug-in installed and require waiting for the plug-into download.

User ProcedureThe student begins by connecting to the URL

address of the laboratory Web site using thebrowser of his or her choice. The 1st screen(see Figure 7) presents the student with a list ofthe experiments available. After choosing theexperiment to carry out, the next screen (see

Figure 6—HTML interface

Figure 7—Start screen

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JFSE: Journal of Food Science Education

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Figure 8) requests a user login and password. If the student doesnot 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 some-thing similar to Figure 5. The user can choose the appropriate set-tings for the experiment by using the different controls providedand pressing the “Commit” button once all the values are set. Thesystem receives updated values every second, and the informa-tion is displayed on the bottom part of the screen. There is a link(“HELP” button) for the student to open an HTML file that de-scribes the concepts important to the experiment. There is also alink to the instructor’s e-mail address.

If a student has chosen the HTML interface, a screen will beseen similar to the one shown in Figure 6, which automatically re-loads with updated information every 5 s. To change the differentsettings, the student must click on the “Click to set the conditions”link, and a new screen will load where he or she may enter thedesired settings. After doing so, the main screen returns with theupdated image and sensor readings.

After logging off from the experiment, the last screen thanks thestudent, and a set of questions are asked for feedback regarding

the experiment. The student is also given the option to downloadthe collected data for further analysis or have it emailed to his orher account.

The above-described setup has been regularly used in labora-tory courses taught at the Univ. of California, Davis. Furthermore,instructors and students from other institutions in the U.S. andoverseas (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 pa-per, should provide the necessary background to develop newexperiments that are remotely controlled on the Internet. Avail-ability of such experiments will provide a major educational re-source in food science for instructors and students to share thelearning experience on a worldwide basis.

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Figure 8—Login screenA