CPS Design with Learning-Enabled Components: A Case Study (review)

(source: CPS Design with Learning-Enabled Components: A Case Study)
no copyright infringement intended

CPS Design with Learning-Enabled Components: A Case Study

Charles Hartsell, Nagabhushan Mahadevan, Shreyas Ramakrishna, Abhishek Dubey, Taylor Johnson, Xenofon Koutsoukos, Janos Sztipanovits, Gabor Karsai

Institute for Software Integrated Systems, Vanderbilt University

Cyber-Physical Systems (CPS [1]) integrate hardware/software components with mechanical/electronic equipment to operate in applications for robotics, avionics, smart grids, you name it. This paper presents a case-study for the design of a CPS to control the movement of an autonomous Unmanned-Underwater-Vehicle (UUV - some call it submarine drone [2, 3]).  The UUV tracks, using images from a forward-looking camera, a pipe placed on the seafloor.

Several aspects are to be considered. Firstly, the innate degree of uncertainty due to the complex interactions inside the system and between the system and the environment. The traditional control technologies show their limits and are replaced by CPSs based on Learning-Enabled-Components (LEC [4]).  Secondly, the security-critical nature of these applications: they must react correctly even to events that happen only rarely. One would say that here is a fluid space, where the only reasonable attitude is to expect the unexpected. Anyway, the design must comply to certification processes requiring safety assurance arguments backed by substantial evidence [5, 6]. Thirdly, all this complexity requires a framework supporting environment simulation and also testing in the earlier stages, including on the software models [7]. The authors used as development framework the Assurance-based-Learning-enabled CPS Toolchain (ALC [5]), a veritable engineering studio, rich in tools and workflows.

The development starts with the modeling of components and messages. ALC puts here three tools: the SysML language [8] to define the components as blocks, the Robot-Operating-System (ROS [9]) for inter-components communication, and the WebGME [10] infrastructure for instantiating the blocks, to get the whole architectonic model. Anytime when the original blocks are modified, ALC updates their instantiations automatically. For each block can be various implementation solutions. All these implementations will be evaluated to get the optimum.

Follows the LEC construction. ALC allows the developers to insert code in their blocks. For the UUV application Python was used. Data are generated using a Gazebo [11] environment simulator (the authors are currently integrating the SCENIC [12] language for data generation). ALC supports training through Artificial-Neural-Networks [4], and the authors used the supervised learning [13]. The goal is to approximate the ideal mapping function from a set of input variables to a corresponding set of output variables. The whole process is iterative.

The paper presents in a detailed manner the development cycle, and evaluates the results obtained for diverse changes of conditions (various architectures for the neural networks, various geometries of the pipeline, etc.) The concluding section identifies also possible avenues for future research, related to the formalization and quantitative evaluation of safety case arguments [14].
The authors are with the Vanderbilt University.  Paper level: industry/academia.


REFERENCES
1. Abhishek Ghosh, What is Cyber-Physical System (CPS), The Customized Windows, January 3, 2018,  https://thecustomizewindows.com/2018/01/cyber-physical-system-cps/
2. Dan Gettinger, What you need to know about underwater drones, Center for the Study of the Drone at Bard College, 2015, https://robohub.org/what-you-need-to-know-about-underwater-drones/
3. Dan Gettinger, Underwater Drones (Updated), Center for the Study of the Drone at Bard College, 2016, https://dronecenter.bard.edu/underwater-drones-updated/
4. Simon Haykin, Neural Networks and Learning Machines, Third Edition,  Pearson Education, Inc., Upper Saddle River, NJ, 2009, http://dai.fmph.uniba.sk/courses/NN/haykin.neural-networks.3ed.2009.pdf
5. Shreyas Ramakrishna, Charles Hartsell, Abhishek Dubey, Partha Pal, Gabor Karsai, A Methodology for Automating Assurance Case Generation, arXiv, 2003, https://arxiv.org/pdf/2003.05388.pdf
6. RTCA. DO-178C - Software Considerations in Airborne Systems and Equipment Certification. December 2011, https://www.qa-systems.com/index.php?id=727
7. Carlos A. Gonzalez, Mojtaba Varmazyar, Shiva Nejati, Lionel C. Briand, Yago Isasi, Enabling Model Testing of Cyber-Physical Systems, ACM/IEEE 21th International Conference on Model Driven Engineering Languages and Systems (MODELS ’18), October 14–19, 2018, Copenhagen, Denmark, https://dl.acm.org/doi/pdf/10.1145/3239372.3239409
8. OMG. OMG Systems Modeling Language (OMG SysML), Version 1.5, 2017, http://www.omgwiki.org/OMGSysML/lib/exe/fetch.php?media=sysml-roadmap:sysml_v2_requirement_support_document_2017-09-23-omg_syseng-2017-09-01.pdf
9. Morgan Quigley, Brian Gerkey, Ken Conley, Josh Faust, Tully Foote, Jeremy Leibs, Eric Berger, Rob Wheeler, Andrew Ng, ROS: an open-source Robot Operating System, ICRA Workshop on Open Source Software, 2009, https://www.semanticscholar.org/paper/ROS%3A-an-open-source-Robot-Operating-System-Quigley-Conley/d45eaee8b2e047306329e5dbfc954e6dd318ca1e
10. Miklós Maróti, Tamás Kecskés, Róbert Kereskényi, Brian Broll, Péter Völgyesi, László Jurácz, Tihamer Levendovszky, and Ákos Lédeczi. Next generation (meta) modeling: Web-and cloud-based collaborative tool infrastructure. Proceedings of MPM MPM@ MoDELS, 1237:41–60, 2014, http://ceur-ws.org/Vol-1237/paper5.pdf
11. Nathan P Koenig, Andrew Howard, Design and use paradigms for gazebo, an open-source multi-robot simulator, Proceedings of 2004 IEEE/RSJ International Conference on Intelligent Robots and Systems. Citeseer, 2004, http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.304.8999&rep=rep1&type=pdf
12. Daniel J. Fremont, Tomasso Dreossi, Shromona Ghosh, Xiangyu Yue, Alberto L. Sangiovanni-Vincentelli, Sanjit A. Seshia. SCENIC: a language for scenario specification and scene generation, Proceedings of the 40th ACM SIGPLAN Conference on Programming Language Design and Implementation, pages 63–78. ACM, 2019, https://dl.acm.org/doi/pdf/10.1145/3314221.3314633
13. Ian Goodfellow, Yoshua Bengio, Aaron Courville, Deep Learning, MIT Press, Cambridge, MA, 2016, https://www.deeplearningbook.org/
14. Rui Wang, Jérémie Guiochet, Gilles Motet, Confidence Assessment Framework for Safety Arguments,  Computer Safety, Reliability, and Security: 36th International Conference, SAFECOMP 2017, Trento, Italy, September 13-15, 2017, Proceedings (pp.55-68), https://www.researchgate.net/publication/319138629
_Confidence_Assessment_Framework_for_Safety_Arguments

Mosaic from the Church of Hagios Demetrios, Thessaloniki

(source: FB page of Татьяна Тагачина)
no copyright infringement intended

Thessaloniki. Mosaic from the Church of Hagios Demetrios late 7th or early 8th century, showing St. Demetrios with donors

(Icon and Orthodoxy)

Should We Cancel Aristotle?

(source: NY Times)
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He defended slavery and opposed the notion of human equality. But he is not our enemy. An article by Agnes Callard. She is a philosopher and professor.

Should We Cancel Aristotle? https://t.co/JvCW9mnNg5

— Pierre Radulescu (@pierreradulescu) July 22, 2020

(Zoon Politikon)

A. E. Stallings, The Sculptor vs. the Poet

Marble can be toppled, yet words are eternal
(source: The American Scholar)
no copyrightr infringement intended

A. E. Stallings in The American Scholar:

I am not a sculptor, wrote Pindar in the fifth century B.C., at the beginning of his Fifth Nemean Ode, to fashion statues that stand around doing nothing, each stuck on its self-same base. Rather, he makes sweet song that can board every ship and fly in all directions at once, proclaiming its news: in this case, the victory of a certain Pytheas at the no-holds-barred boxing match called the pancratium at the Nemean Games. Some athletes were indeed honored with statues to commemorate their victories, but such memorials were single and stationary and subject to all the insults of time. Pindar’s poem wings its way unscathed over the centuries, and now is disseminated not only on paper, but electronically, across the Internet, all over the world.

It turns out that poetry and sculpture have a long history of vying for top honors as modes of memorial. I have been thinking of this a lot these past days, with the removal of statues so much in the news, along with the subsequent debate about how and what we commemorate. It is an old argument, in which poetry tends to get the last word. (There are, of course, sculptors who are poets and poets who are sculptors: Michelangelo might have been known primarily as a sonneteer, had he not been such a star in the visual arts. The contemporary poet Meredith Bergman is also a sculptor, currently at work on a statue group of Women’s Rights Pioneers in Central Park, the first such depiction in the park, believe it or not, of a non-fictive woman.)

Take Horace’s Ode 3.30, which begins, I have built a monument more lasting than bronze / and higher than the royal edifice of the pyramids, which neither weathering rain nor wind nor years has been able to destroy. Is it perhaps somewhat tongue in cheek, more lighthearted than its opening would appear? Yet here the poem stands, as fresh as the day it was composed, sometime in the first century B.C., shrugging off the dust of years.

Shakespeare’s sonnets also like to assert the relative stamina of verse:

Not marble, nor the gilded monuments
Of princes, shall outlive this powerful rhyme;
But you shall shine more bright in these contents
Than unswept stone, besmear’d with sluttish time.
When wasteful war shall statues overturn,
And broils root out the work of masonry,
Nor Mars his sword nor war’s quick fire shall burn
The living record of your memory.

Statues only seem permanent. Reputation, however, is preserved not in a stone or brazen image, but in language, which continually revives by being read and spoken through the mouths of the living, phrases that may pass, translated, into tongues that didn’t even exist when they were composed.

A reputation may erode, leaving the monument to it bereft of its anchoring grandeur, in a state of ironic disrepair. Shelley’s Ozymandias (1818) is the locus classicus here:

I met a traveller from an antique land
Who said: Two vast and trunkless legs of stone
Stand in the desert. Near them, on the sand,
Half sunk, a shattered visage lies, whose frown,
And wrinkled lip, and sneer of cold command,
Tell that its sculptor well those passions read
Which yet survive, stamped on these lifeless things,
The hand that mocked them and the heart that fed:
And on the pedestal these words appear:
‘My name is Ozymandias, king of kings:
Look on my works, ye Mighty, and despair!’
Nothing beside remains. Round the decay
Of that colossal wreck, boundless and bare
The lone and level sands stretch far away.

That the sculptor reads the pharaoh’s passions, and stamps them on the lifeless things, is telling. In the inscription, the statue speaks, in the first person, but his words have come to mean the opposite of his intention. It is noteworthy that even news of this has to be brought to the poet by a traveller. The traveller happens to be the first-century B.C. historian Diodorus Siculus, whose description of the statue and the inscription inspires Shelley and also Horace Smith (see below). So in a sense the traveller is not a person, but a written text, which has journeyed not only from a storied land, but also through time, from antiquity itself.

The poem may have been partly inspired by the British Museum’s acquisition (I’ll leave that vague term for the present) of a fragment of a huge statue of Ramses II (Ozymandias being the Greek for Ramses)—yet another layer of irony, as the statue’s grim visage, depicted as unmoved in its ancient situ against a backdrop of the sands of time, is en route to London on a ship even as Shelley writes.

Not all poems about statues are immortal, or somehow more permanent than the statues they address. Shelley’s contemporary Horace Smith wrote a poem on the same subject (both it and Ozymandias resulted from a sonnet competition between the poets). Smith’s sonnet begins, somewhat unfortunately, In Egypt’s sandy silence, all alone, / Stands a gigantic Leg, and it is remembered today only as a foil to Shelley’s masterpiece.

Resonantly, though, especially for our moment, Smith’s post-volta sestet imagines a future London where 19th-century statues are in a similar state of decay and anonymity. His image of a postapocalyptic London, where nature has returned and people are scarce, has an eerie quarantine quality to it now:

We wonder,—and some Hunter may express
Wonder like ours, when thro’ the wilderness
Where London stood, holding the Wolf in chace,
He meets some fragment huge, and stops to guess
What powerful but unrecorded race
Once dwelt in that annihilated place.

One ponders who that fragment huge would be.

Ozymandias is the main influence on another famous sonnet on a statue—or rather, two statues, one vanished, known only by its descriptions, the other more recently erected, Emma Lazarus’s famed The New Colossus (1883) for the Statue of Liberty:

Not like the brazen giant of Greek fame,
With conquering limbs astride from land to land;
Here at our sea-washed, sunset gates shall stand
A mighty woman with a torch, whose flame
Is the imprisoned lightning, and her name
Mother of Exiles. From her beacon-hand
Glows world-wide welcome; her mild eyes command
The air-bridged harbor that twin cities frame.

“Keep, ancient lands, your storied pomp!” cries she
With silent lips. “Give me your tired, your poor,
Your huddled masses yearning to breathe free,
The wretched refuse of your teeming shore.
Send these, the homeless, tempest-tost to me,
I lift my lamp beside the golden door!”

The brazen giant of Greek fame is the Colossus of Rhodes, one of the seven wonders of the ancient world. Built in 280 BC to commemorate the successful resistance of a siege, it was a bronze statue of the sun god Helios that stood at about the same height as our Statue of Liberty, the largest such statue in the ancient world. It was toppled by an earthquake in 226 B.C. and left in fragments huge. The engineering triumph of the day, designed to last the ages, it stood for a mere 54 years.

The correspondences to Shelley’s poem are many, not least in the title The New Colossus, which harkens back to Shelley’s colossal wreck, but also in the phrasing: his cold command becomes mild eyes command. Other correspondences include beacon-hand and ancient lands, and then there are the silent lips that still speak, in the first person. Her name is not Ozymandias, but Mother of Exiles. Interestingly, she is not a figure from the past, but from the future tense, or perhaps an optimistic hortative mood: Here at our sea-washed sunset gates shall stand. The New World confronts the Old.

Emma Lazarus hailed from a large Sephardic Jewish family and was active in the cause of Jewish refugees fleeing Russia. The current administration is not fond of the welcoming message this poem conveys, and in August 2019 in an interview with NPR, Ken Cuccinelli, acting head of Citizenship and Immigration Services, was asked, Would you also agree that Emma Lazarus’s words etched on the Statue of Liberty, ‘Give me your tired, give me your poor,’ are also a part of the American ethos? They certainly are, Cuccinelli responded. Give me your tired and your poor—who can stand on their own two feet and who will not become a public charge.

Those clunky lines do not rhyme or scan, and this off-the-cuff and, one hopes, facetious suggestion could never be implemented. A poem, unlike a statue, doesn’t need to stand on its own two feet—it wings its way into the world in all directions at once. In a metaphor that Pindar might have appreciated, it can go viral. It can be lost in the transmission of time, but it cannot be dismantled. As Robert Frost says, The utmost of ambition [of the poet] is to lodge a few poems where they will be hard to get rid of. To be widely anthologized, widely disseminated on the Internet, makes a poem a flame almost impossible to extinguish.

Or as Pindar might say, that ship has sailed.





(A. E. Stallings)

Vasile Ernu, Ultima Noapte la Istanbul

Photo: Ara Güler
(source: FB page of Vasile Ernu)
no copyright infringement intended

Vasile Ernu: La Istanbul ... am simţit cum explodează viaţa. Aici am simţit puterea. Prin toţi porii oraşului. Oraşul duduie şi vezi o societate foarte tînără şi energică. Turcia este ţara cu cei mai mulţi tineri din regiune, iar Istanbulul e genul de oraş fabrică: peste tot, ceva, cineva produce ceva. Atenţie, nu doar vinde, ci şi produce ceea ce vinde ... totul e o proiecţie spre viitor, chiar dacă viitorul e un soi de reciclare a trecutului. Aici şi bătrînul are ceva foarte energic şi tînăr.

Citiţi intreaga istorie aici:

Ultima noapte la Istanbul - În loc de final: poveștile bunicilor

(Vasile Ernu)

Kōji Shiraishi, Grotesque, 2009

Grotesque (グロテスク, Gurotesuku)
(source: vcinema)
no copyright infringement intended

A horror movie. Hopefully not a live show or something (for actors' sake, WTF).

Kōji Shiraishi, Grotesque (グロテスク, Gurotesuku), 2009
(video by black jack)

(Japanese Cinema)