Labs and Simulations on iOS Devices ... visual programming interface and provides users with a ... applications include the iOS by Apple, Android, Windows.
Session F2G
Work in Progress - Interactive Signal-Processing Labs and Simulations on iOS Devices Jinru Liu, Andreas Spanias, Mahesh K. Banavar, Jayaraman J. Thiagarajan, Karthikeyan Natesan Ramamurthy, Shuang Hu and Xue Zhang SenSIP Center, School of ECEE, Arizona State University {jinru.liu, spanias, maheshkb, jjayaram, knatesan, shuang.hu.1, xue.zhang.2}@asu.edu
Abstract – Handheld devices are increasingly finding more applications in STEM education. In this paper, we present the design of an interactive signal processing simulation software operating on both the iPhone OS (iOS) and Android platforms. This object-oriented application is called i-JDSP and is conceptually based on the award-winning Java-DSP (J-DSP) simulation environment. The i-JDSP app offers a user-friendly visual programming interface and provides users with a compelling multi-touch programming experience. It supports basic signal processing simulation functions such as the FFT, filtering, frequency response, pole-zero plots, and sound recording and playback. Initial assessments have been promising and we believe that this new attractive smartphone interface will make signal processing education among undergraduate students more appealing.
To address these problems and challenges, i-JDSP, an interactive signal-processing simulation environment that offers an intuitive, all-graphical programming experience on the iOS platform has been developed. The i-JDSP application has currently been developed for the iOS platform and a free beta version is anticipated for release on the Apple App Store in September 2011. The Android version development has started and a beta version is planned to be released by December 2011. The following sections concentrate on the layout and structure, and the evaluations of i-JDSP on the iOS platform. THE i-JDSP ENVIRONMENT
i-JDSP is based on the award winning on-line laboratory J-DSP [3, 8, 9] software. i-JDSP for the iOS devices has been developed in C and Objective C as a native Cocoa Touch application that can be run on any iOS device. The Android i-JDSP is developed using Java and the Index Terms – DSP, iOS, Android, iPad, iPod, Apple, Android SDK and intended to run on the Android OS interactive laboratory, educational software. running on tablets and mobile phones. Similar to J-DSP, all functions in i-JDSP are INTRODUCTION represented by graphical blocks that can be visually added Advanced mobile devices are capable of handling relatively to the main simulation view of the application. The user complex tasks such as word processing, complex Internet interface of i-JDSP is designed to provide maximum transactions, and even human motion analysis [1]. The most drawing space with minimum navigational controls. popular platforms available for developing mobile Furthermore, operations on i-JDSP are entirely applications include the iOS by Apple, Android, Windows performed using intuitive multi-touch and drag-and-drop Mobile, Symbian, and BlackBerry. The authors believe that controls. Signal processing blocks selected from a menu can the design of exciting mobile education applications be placed, moved and connected to other blocks. With a represents a great opportunity to build student interest and double-tap, users can access parameters, properties and enthusiasm in science and engineering. other advanced features of each block. Figure 1 shows an Software deployed via Java applets such as [2-6] are example of a filter simulation in i-JDSP. Controls to add platform independent, and can be used on laptops. The new blocks or to reset the simulation are visible on the top current task is to develop software that can be deployed as of the screen. A pole-zero placement example is shown in stand-alone programs on mobile devices such as smartFigure 2. Double-tapping the block brings up the blockphones and tablets. Recent efforts include the MATLAB execution screen as shown. Because of the multi-touch Mobile [7] interface. This provides a lightweight mobile technology, users can move multiple pairs of poles and desktop that can connect via the Internet to the MATLAB zeros on the graph at the same time while observing the software running on a remote computer. It features a dynamic changes to the frequency response of the traditional command line interface and allows users to type corresponding filter on the right. Convolution is also commands, execute scripts and view the corresponding demonstrated graphically on i-JDSP [10]. An example of a results. However, this application requires a running pulse being convolved with a sinc signal is shown in Figure instance of MATLAB on a remote machine, and access via 3. The figure shows the convolution in progress. The the Internet. amplitude of the output of the convolution is enhanced to make it more visible. 978-1-61284-469-5/11/$26.00 ©2011 IEEE October 12 - 15, 2011, Rapid City, SD 41st ASEE/IEEE Frontiers in Education Conference F2G-1
Session F2G
FIGURE 2. POLE-ZERO PLACEMENT SIMULATION IN i-JDSP.
The capabilities of the i-JDSP environment allow students to experiment with basic DSP concepts on their mobile devices without the need of a computer and Internet connectivity. A laboratory exercise was developed for a group of students from the EEE 407 Spring 2011 undergraduate DSP class. Students were asked to simulate a causal system on i-JDSP and were asked to study the stability of the system. Students were then asked to use the pole-zero placement block to add a pair of poles to the zplane and then study the system response when the pole locations were changed. In addition, the students were also asked questions about the ease of use of i-JDSP as a simulation tool using a general usage form. The general usage form is used to obtain an overall subjective opinion on i-JDSP application for iOS devices. The questions were designed in order to evaluate the usability and merits of the new interface in comparison to the existing desktop version of J-DSP. Student interest in using mobile devices as a simulation platform was also assessed. Selected assessment results are shown in Table 1.
Disagree (%)
Strongly Disagree (%)
17
83
0
0
0
39
39
17
5
0
44
50
6
0
0
50
38
6
6
0
56
39
0
5
0
Assessment of the student responses reveals that the impact of i-JDSP is positive. Most students agreed that the graphical user interface (GUI) of i-JDSP is highly intuitive. In fact, around 95% of the students reported that it took them less than 5 minutes to learn how to use i-JDSP to design simple block diagrams. Moreover, 94% of the students liked the idea of a using a mobile device based DSP application such as i-JDSP. The responses also indicate most of them are inclined to install the application on their own devices when i-JDSP is made available in the app store. Additional assessment and interviews are being conducted and results will be presented at the conference. Pre- and post-quizzes are also being administered this spring.
FIGURE 3. CONVOLUTION IN PROGRESS IN i-JDSP ON AN iPHONE.
ASSESSMENTS
Neutral (%)
FIGURE 1. FILTER SIMULATION IN i-JDSP ON AN IPHONE.
Do you think it is useful to perform DSP laboratories using the iPad/iPhone? The menus in i-JDSP is intruitive and easy to navigate through? Will you install the app if it is available free in the app store? Using the blocks and modifying their parameters was easy and intuitive in iJDSP? Setting up the simulations on the mobile device was easy?
Agree (%)
Evaluation Questions
Strongly Agree (%)
TABLE 1. STATISTICS BASED ON THE GENERAL USAGE ASSESSMENT.
ACKNOWLEDGMENT This work has been funded in part by NSF CCLI (TUES) phase 3 award number 0817596. REFERENCES [1]
D. Siewiorek, et. al., "SenSay: a context-aware mobile phone," Proceedings of IEEE ISWC, pp. 248- 249, 18-21 Oct. 2003. [2] A. Spanias and V. Atti, “Interactive online undergraduate laboratories using J-DSP,” IEEE Transactions on Education, vol. 48, no. 4, pp. 735–749, Nov 2005. [3] E. A. Lee, “Overview of the Ptolemy project,” Univ. of California, Berkeley, CA, Tech. Memo. UCB/ERL M03/25, 2003. [4] S. C. Douglas, G. C. Orsak, and M. A. Yoder, “DSP in high schools: New technologies from the Infinity project,” Proceedings of IEEE ICASSP, vol. 4, 2002, pp. 4152–4154. [5] “Speech recognition java demos,” Available online at http://www.isip.msstate.edu/projects/speech/index.html. [6] “The connexions project,” Available online at http://cnx.rice.edu/. [7] MATLAB Mobile, Available online at: http://www.mathworks.com/mobile/. Last accessed 28 Mar. 2011 [8] A. Spanias, Digital Signal Processing: An Interactive Approach. ISBN: 978-1-4243-2524-5, Lulu Publishers, 2007. [9] i-JDSP demonstration video. Available online at http://www.youtube.com/watch?v=-z7QBbd0es8. [10] Demonstration of convolution on i-JDSP. Available online at http://www.youtube.com/watch?v=agi2trifFLk.
978-1-61284-469-5/11/$26.00 ©2011 IEEE October 12 - 15, 2011, Rapid City, SD 41st ASEE/IEEE Frontiers in Education Conference F2G-2
