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Paper Critique #1 Digvijay Singh Electrical Engineering, UCLA

[email protected]

ABSTRACT In this paper, I critique former literature and work on Cyberphysical systems. Comparisons with embedded systems, core issues, future research directions and my personal ideas are the areas of focus.

Categories and Subject Descriptors A.1 [Introductory and Survey]: Cyber-physical systems.

General Terms Documentation, Design, Reliability, Security, Verification.

Keywords Cyber-physical systems, Embedded systems.

Embedded

systems,

Networked

1.INTRODUCTION Embedded systems have become the buzzword in the industry and market in recent times. Daily-life examples like cell-phones and iPods are becoming more and more pervasive. Embedded system design is still in its infancy and most current systems use conventional software techniques and mundane architectural designs. These work reasonably for small ‘isolated’ systems. Although, as systems start to form networks (less isolation) or become more complicated, conventional engineering and computer science wisdom turns out to be lacking the tools to effectively deal with their requirements.

2.CYBER-PHYSICAL Vs. EMBEDDED ‘Embedded systems’ like ‘Cyber-physical systems’ are systems that couple computation with the physical world. These systems (ideally) possess the capability to seamlessly integrate physical world sensing and control with computation. This is the principal difference between future cyber-physical systems and current-day embedded systems which fall short of the required capabilities (especially for large or extensively networked systems).

Modern-day embedded systems, albeit numerous, don’t show a single example of a system with perfectly seamless integration of the cyber and physical world. The main reason for this problem is the basis of such designs which lie in conventional computer science and engineering theory which was never developed with the physical world in mind. These designs tend to view computations as just data manipulation (Turing’s model). This leads to lack of theory that integrates both the physical and cyber world in a unified framework. The vision is to overcome conventional embedded system knowledge and search for new paradigm of system design to create true ‘cyber-physical systems’.

3.CORE ISSUES 3.1Time and Concurrency The notion of time is also an important requirement that all cyber-physical systems exhibit. The basic problem with current computational models is that there is no notion of time present in them. The correct execution of a conventional process has nothing to do with the time it takes (like the Von Neumann architecture where only sequence and not timing of operations is important). This makes it impossible to make perfectly predictable systems due to the inherent unpredictability of the underlying model we use. Cyber-physical systems are also inherently concurrent due to their close coupling with possibly multiple physical world processes. Current programming concepts are not adept at handling concurrency. For example, most multi-tasking is done using process threads and real-time scheduling of these threads is still a problem that has not been solved. The reason for this is not the lack of a scheduling algorithm, but instead the lack of a notion of time and concurrency in the underlying component used to model computation (i.e. a process thread). Instead of trying to force incompatible conventional design wisdom onto embedded systems, the goal should be to develop a unified model which takes into account the physical notion of time and concurrency along with computation.

3.2Frameworks Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. EE202A Fall’08, September, 2008, Los Angeles, CA, USA. Copyright 2008 UCLA.

A framework is a set of rules through which components of a system may interact. Current frameworks don’t necessarily suit the design of cyber-physical systems.1

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This document is part of coursework done for the EE202A fall ’08 course at UCLA. Information used in this paper is for study purposes only and is the copyright of the respective owner(s).

3.3Software

4.FUTURE RESEARCH DIRECTIONS

Please leave 3.81 cm (1.5") of blank text box at the bottom of the left column of the first page for the copyright notice.

Place Tables/Figures/Images in text as close to the reference as possible (see Figure 1). It may extend across both columns to a maximum width of 17.78 cm (7”).

3.4Hardware

Captions should be Times New Roman 9-point bold. They should be numbered (e.g., “Table 1” or “Figure 2”), please note that the word for Table and Figure are spelled out. Figure’s captions should be centered beneath the image or picture, and Table captions should be centered above the table body.

For pages other than the first page, start at the top of the page, and continue in double-column format. The two columns on the last page should be as close to equal length as possible. Table 1. Table captions should be placed above the table Graphics

Top

In-between

Bottom

Tables

End

Last

First

Figures

Good

Similar

Very well

5.MY PERSONAL IDEAS

3.5Networking

The heading of a section should be in Times New Roman 12point bold in all-capitals flush left with an additional 6-points of white space above the section head. Sections and subsequent sub- sections should be numbered and flush left. For a section head and a subsection head together (such as Section 3 and subsection 3.1), use no additional space above the subsection head.

Footnotes should be Times New Roman 9-point, and justified to the full width of the column.

6.ACKNOWLEDGMENTS

Use the “ACM Reference format” for references – that is, a numbered list at the end of the article, ordered alphabetically and formatted accordingly. See examples of some typical reference types, in the new “ACM Reference format”, at the end of this document. Within this template, use the style named references for the text. Acceptable abbreviations, for journal names, can be found here: http://library.caltech.edu/reference/abbreviations/ The references are also in 9 pt., but that section (see Section 7) is ragged right. References should be published materials accessible to the public. Internal technical reports may be cited only if they are easily accessible (i.e. you can give the address to obtain the report within your citation) and may be obtained by any reader. Proprietary information may not be cited. Private communications should be acknowledged, not referenced (e.g., “[Robertson, personal communication]”).

3.6Testing and Verification Do not include headers, footers or page numbers in your submission. These will be added when the publications are assembled.

My thanks to ACM SIGCHI for allowing me to modify templates they had developed. Also, thanks to authors of the references for giving me such great information to use in this document. The information has deeply impacted my views on embedded systems.

7.REFERENCES [1] Bowman, M., Debray, S. K., and Peterson, L. L. 1993. Reasoning about naming systems. ACM Trans. Program. Lang. Syst. 15, 5 (Nov. 1993), 795-825. DOI= http://doi.acm.org/10.1145/161468.161471. [2] Ding, W. and Marchionini, G. 1997 A Study on Video Browsing Strategies. Technical Report. University of Maryland at College Park. [3] Fröhlich, B. and Plate, J. 2000. The cubic mouse: a new device for three-dimensional input. In Proceedings of the SIGCHI Conference on Human Factors in Computing Systems (The Hague, The Netherlands, April 01 - 06, 2000). CHI '00. ACM Press, New York, NY, 526-531. DOI= http://doi.acm.org/10.1145/332040.332491