Archive for the 'Computer technology' Category

Digital dumbing down

Published
by
peter
on 2011-11-26
in Computer technology, Hands and Music
. Closed

Despite being all the rage, touchscreens have never impressed me.   I did not put my finger (metaphor chosen deliberately) on the reasons why until reading Edward Tufte’s criticism:  they have no hand!  They lack tactility, and of all the many possible diverse, sophisticated, subtle, and complex motions that our hands and fingers are capable of, touchscreens seem designed to accommodate just two very simple motions:  tapping and sliding.   Not something to write home about when you wake up each morning eager to digitally percuss, or have hands able  to think.    Bret Victor has a nice graphically-supported argument about the lack of embodiment of touchscreens in the world of those of us with opposable thumbs, here.  As Victor says:

Are we really going to accept an Interface Of The Future that is less expressive than a sandwich?




When are agent models or systems appropriate?

Published
by
peter
on 2011-11-03
in Computer Science, Computer technology and Computing-as-interaction
. Closed

In July 2005, inspired by a talk on formation flying by unmanned aircraft by Sandor Veres at the Liverpool Agents in Space Symposium, I wrote down some rules of thumb I have been using informally for determining whether an agent-based modeling (ABM) approach is appropriate for a particular application domain.  Appropriateness is assessed by answering the following questions:

1. Are there multiple entities in the domain, or can the domain be represented as if there are?
2. Do the entities have access to potentially different information sources or do they have potentially different beliefs? For example, differences may be due to geographic, temporal, legal, resource or conceptual constraints on the information available to the entities.
3. Do the entities have potentially different goals or objectives? This will typically be the case if the entities are owned or instructed by different people or organizations.
4. Do the entities have potentially different preferences (or utilities) over their goals or objectives ?
5. Are the relationships between the entities likely to change over time?
6. Does a system representing the domain have multiple threads of control?

If the answers are YES to Question 1 and also YES to any other question, then an agent-based approach is appropriate. If the answer to Question 1 is NO, or if the answers are YES to Question 1 but NO to all other questions, then a traditional object-based approach is more appropriate.

Traditional object-oriented systems involve static relationships between non-autonomous entities sharing the same beliefs, preferences and goals, and in a system with a single thread of control.




Resilient capitalism

Published
by
peter
on 2011-10-20
in Computer technology, Design, Forecasting and Science
. Closed

Yesterday began with a meeting at an investment bank in Paternoster Square, London, which turned out to be inaccessible to visitors and the public.   The owners of the Square had asked the police to close public access to prevent its occupation by the anti-capitalism (OWS) protesters, encamped between the Square and St Paul’s Cathedral.  So our meeting took place in a cafe beside the square.

The day ended with a debate at the Royal Society, organized by The Foundation for Science and Technology, on developing adaptation policy in response to climate change.     The speakers were Dr Rupert Lewis of DEFRA, Sir Graham Wynne of the Sub-Committee on Adaptation, UK Committee on Climate Change, and Tom Bolt, Director of Performance Management at LLoyd’s of London.  (Their presentations will eventually be posted here.) As Bolt remarked, insurance companies have to imagine potential global futures in which climate change has wrecked social and economic havoc, and so are major consumers of scientific prognoses.   One commentator from the audience suggested that insurers, particularly, may have a vested short-term financial interest in us all being pessimistic about the long term future, although this inference was not obvious to me:  one human reaction to a belief in a certainly-ruinous future is not to save or insure for it, but rather to spend today.

A very interesting issue raised by some audience members is just how do we engineer and build infrastructure for adaptability?  What would a well-adapted society look like?     One imagines that the floating houses built in the Netherlands to survive floods would fit any such description.  Computer scientists have some experience in creating and managing robust, designing resilient and adaptive systems, and so it may be useful to examine that experience for lessons for design and engineering efforts for other infrastructure.




Digital aspen forests

Published
by
peter
on 2011-10-17
in Computer Science, Computer technology, Economics and Getting-things-done intelligence
. Closed

Brian Arthur has an article about automated and intelligent machine-to-machine communications creating a second digital economy underlying the first physical one, in the latest issue of The McKinsey Quarterly here.

I want to argue that something deep is going on with information technology, something that goes well beyond the use of computers, social media, and commerce on the Internet. Business processes that once took place among human beings are now being executed electronically. They are taking place in an unseen domain that is strictly digital. On the surface, this shift doesn’t seem particularly consequential—it’s almost something we take for granted. But I believe it is causing a revolution no less important and dramatic than that of the railroads. It is quietly creating a second economy, a digital one.

. . . .

We do have sophisticated machines, but in the place of personal automation (robots) we have a collective automation. Underneath the physical economy, with its physical people and physical tasks, lies a second economy that is automatic and neurally intelligent, with no upper limit to its buildout. The prosperity we enjoy and the difficulties with jobs would not have surprised Keynes, but the means of achieving that prosperity would have.

This second economy that is silently forming—vast, interconnected, and extraordinarily productive—is creating for us a new economic world. How we will fare in this world, how we will adapt to it, how we will profit from it and share its benefits, is very much up to us.”

Reference:

W. Brian Arthur [2011]:  The Second Economy.  The McKinsey Quarterly, October 2011.




Vale Dennis Ritchie (1941-2011)

Published
by
peter
on 2011-10-15
in Computer Science, Computer technology, Matherati and Obituaries
. Closed

A post to note the passing on of Dennis Ritchie (1941-2011), co-developer of C programming language and of the Unix operating system.  The Guardian’s obituary is here, a brief note from Wired Magazine here, and John Naughton’s tribute in the Observer here.    So much of modern technology we owe to just a few people, and Ritchie was one of them.

An index to posts about the Matherati is here.




Antikythera

Published
by
peter
on 2010-12-18
in Classics, Computer Science, Computer technology, Computing-as-interaction, History, Mathematics and Prophecy
. Closed

An orrery is a machine for predicting the movements of heavenly bodies.   The oldest known orrery is the Antikythera Mechanism, created in Greece around 2100 years ago, and rediscovered in 1901 in a shipwreck near the island of  Antikythera (hence its name).   The high-quality and precision nature of its components would indicate that this device was not unique, since the making of high-quality mechanical components is not trivial, and is not usually achieved with just one attempt (something Charles Babbage found, and which delayed his development of computing machinery immensely).

It took until 2006 and the development of x-ray tomography for a plausible theory of the purpose and operations of the Antikythera Mechanism to be proposed (Freeth et al. 2006).   The machine was said to be a physical examplification of  late Greek theories of cosmology, in particular the idea that the motion of a heavenly body could  be modeled by an epicycle – ie, a body traveling around a circle, which is itself moving around some second circle.  This model provided an explanation for the fact that many heavenly bodies appear to move at different speeds at different times of the year, and sometimes even (appear to) move backwards.

There have been two recent developments:  One is the re-creation of the machine (or, rather, an interpretation of it)  using lego components.

The second has arisen from a more careful examination of the details of the mechanism.  According to Marchant (2010), some people now believe that the mechanism examplifies Babylonian, rather than Greek, cosmology.   Babylonian astronomers modeled the movements of heavenly bodies by assuming each body traveled along just one circle, but at two different speeds:  movement in one period of the year being faster than during the other part of the year.

If this second interpretation of the Antikythera Mechanism is correct, then perhaps it was the mechanism itself (or others like it) which gave late Greek astronomers the idea for an epicycle model.   In support of this view is the fact that, apparently, gearing mechanisms and the epicycle model both appeared around the same time, with gears perhaps a little earlier.   So late Greek cosmology (and perhaps late geometry) may have arisen in response to, or at least alongside, practical developments and physical models.   New ideas in computing typically follow the same trajectory – first they exist in real, human-engineered, systems; then, we develop a formal, mathematical theory of them.   Programmable machines, for instance, were invented in the textile industry in the first decade of the 19th century (eg, the Jacquard Loom), but a mathematical theory of programming did not appear until the 1960s.   Likewise, we have had a fully-functioning, scalable, global network enabling multiple, asynchronous, parallel, sequential and interleaved interactions since Arpanet four decades ago, but we still lack a thorough mathematical theory of interaction.

And what have the Babylonians ever done for us?   Apart from giving us our units for measuring of time (divided into 60) and of angles (into 360 degrees)?

References:

T Freeth, Y Bitsakis, X Moussas, JH Seiradaki, A Tselikas, H Mangou, M Zafeiropoulou, R Hadland, D Bate, A Ramsey, M Allen, A Crawley, P Hockley, T Malzbender, D Gelb,W Ambrisco and MG Edmunds [2006]:  Decoding the ancient Greek astronomical calculator known as the Antikythera Mechanism.  Nature,  444 (30):   587-591.  30 November 2006.

J. Marchant [2010]:  Mechanical inspiration.  Nature, 468:  496-498.  25 November 2010.




The writing on the wall

Published
by
peter
on 2010-10-08
in Books and Computer technology
. Closed

Over at Normblog, Norm tells us that he wants his books and not merely the words they contain.   We’ve discussed this human passion before:  books, unlike e-readers, are postcards from our past-self to our future-self, tangible souvenirs of the emotions we had when we first read them.   For that very reason – that they transport us through time – books aren’t going anywhere.  It’s a very rare technology indeed that completely eliminates all its predecessors, since every technology has something unique it provides to some users or other.   We could ask, for example, why we still carve words onto stone and why we still engrave names onto rings and pewter mugs for special occasions, when the invention of printing should have done away with those earlier text-delivery platforms, more expensive and less portable than books and paper?




The long after-life of design decisions

Published
by
peter
on 2010-08-17
in Computer Science, Computer technology, History and Telecommunications
. Closed

Reading Natasha Vargas-Cooper’s lively romp through the 1960s culture referenced in the TV series Mad Men, I came across Tim Siedell’s discussion of a witty, early 1960s advert by Doyle Dane Bernbach for Western Union telegrams, displayed here.  Since I am unable to download the advert, in its place is this Western Union telegram sent in May 1944:

Seeing a telegram for the first time in about, oh, 35 years*, I looked at the structure.   Note the header,with information about the company, as well as meta-information about the message.   That structure immediately brought to mind the structure of a TCP packet.

The Transmission Control Protocol (TCP) is the work-horse protocol of the Internet, and was developed by Vince Cerf and Bob Kahn in 1974.   Their division of the packet contents into a header-part (the control information) and a data part (the payload) no doubt derived from earlier work on the design of packets for packet-switched networks.   Later packets (eg, for IP, the Internet Protocol) were simpler, but still retained this two-part structure.  This two-part division is also found in voice telecommunications at the time, for example in Common Channel Signalling Systems, which separated message content from information about the message (control information).   Such systems were adopted internationally by the ITU for voice communications from Signalling System #6 (SS6) in 1975 onwards.  In case the packet design seems obvious, it is worth considering some alternatives:  the meta-information could be in a footer rather than in a header, or enmeshed in the data itself (as, for example, HTML tags are enmeshed in the content they modify).  Or, the meta-data could be sent in a separate packet, perhaps ahead of the data packet, as happens with control information in Signalling System #7 (SS7).  There are technical reasons why some of these design possibilities are not feasible or not elegant, and perhaps the same reasons apply to transmission of telegrams (which is, after all, a communications medium using packets).

The first commercial electrical telegraph networks date from 1837, and the Western Union company itself dates from 1855 (although created from the merger of earlier companies).  I don’t know when the two-part structure for telegrams was adopted, but it was certainly long before Vannevar Bush predicted the Internet in 1945, and long before packet-switched communications networks were first conceived in the early 1960s.   It is interesting that the two-part structure of the telegram lives on in the structure of internet packets.

* Footnote: As I recall, I sent my first email in 1979.

Reference:

Tim Siedell [2010]: “Western Union:  What makes a great ad?” pp. 15-17 of:  Natasha Vargas-Cooper [2010]:  Mad Men Unbuttoned. New York, NY:  HarperCollins.

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As we once thought

Published
by
peter
on 2010-08-17
in AI, Computer Science, Computer technology, Computing-as-interaction, Forecasting, Logic and Mathematics
. Closed

The Internet, the World-Wide-Web and hypertext were all forecast by Vannevar Bush, in a July 1945 article for The Atlantic, entitled  As We May Think.  Perhaps this is not completely surprising since Bush had a strong influence on WW II and post-war military-industrial technology policy, as Director of the US Government Office of Scientific Research and Development.  Because of his influence, his forecasts may to some extent have been self-fulfilling.

However, his article also predicted automated machine reasoning using both logic programming, the computational use of formal logic, and computational argumentation, the formal representation and manipulation of arguments.  These areas are both now important domains of AI and computer science which developed first in Europe and which still much stronger there than in the USA.   An excerpt:

The scientist, however, is not the only person who manipulates data and examines the world about him by the use of logical processes, although he sometimes preserves this appearance by adopting into the fold anyone who becomes logical, much in the manner in which a British labor leader is elevated to knighthood. Whenever logical processes of thought are employed—that is, whenever thought for a time runs along an accepted groove—there is an opportunity for the machine. Formal logic used to be a keen instrument in the hands of the teacher in his trying of students’ souls. It is readily possible to construct a machine which will manipulate premises in accordance with formal logic, simply by the clever use of relay circuits. Put a set of premises into such a device and turn the crank, and it will readily pass out conclusion after conclusion, all in accordance with logical law, and with no more slips than would be expected of a keyboard adding machine.

Logic can become enormously difficult, and it would undoubtedly be well to produce more assurance in its use. The machines for higher analysis have usually been equation solvers. Ideas are beginning to appear for equation transformers, which will rearrange the relationship expressed by an equation in accordance with strict and rather advanced logic. Progress is inhibited by the exceedingly crude way in which mathematicians express their relationships. They employ a symbolism which grew like Topsy and has little consistency; a strange fact in that most logical field.

A new symbolism, probably positional, must apparently precede the reduction of mathematical transformations to machine processes. Then, on beyond the strict logic of the mathematician, lies the application of logic in everyday affairs. We may some day click off arguments on a machine with the same assurance that we now enter sales on a cash register. But the machine of logic will not look like a cash register, even of the streamlined model.”

Edinburgh sociologist, Donald MacKenzie, wrote a nice history and sociology of logic programming and the use of logic of computer science, Mechanizing Proof: Computing, Risk, and Trust.  The only flaw of this fascinating book is an apparent misunderstanding throughout that theorem-proving by machines  refers only to proving (or not) of theorems in mathematics.    Rather, theorem-proving in AI refers to proving claims in any domain of knowledge represented by a formal, logical language.    Medical expert systems, for example, may use theorem-proving techniques to infer the presence of a particular disease in a patient; the claims being proved (or not) are theorems of the formal language representing the domain, not necessarily mathematical theorems.

References:

Donald MacKenzie [2001]:  Mechanizing Proof: Computing, Risk, and Trust (2001).  Cambridge, MA, USA:  MIT Press.

Vannevar Bush [1945]:  As we may think.  The Atlantic, July 1945.

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Those pesky addition symbols

Published
by
peter
on 2010-08-15
in Computer Science and Computer technology
. Closed

On 28 March 1979, there was a partial core meltdown in a reactor at the Three Mile Island Nuclear Power Generating Station near Harrisburg, PA, USA.  The accident was soon headline news, at least throughout the western world.   An obscure computer programmer apparently hearing this news had a crisis of conscience and, in April 1979, phoned anonymously to the  US Nuclear Regulatory Commission, telling them to examine particular program code used in the design of certain types of nuclear reactors.   The code in question was a subroutine intended to calculate the total stresses on pipes carrying coolant water, but instead of adding the different stresses, the routine subtracted them.  So the resulting coolant pipes were extra-thin instead of being extra-thick.

This story would not surprise anyone with any software development experience.   Few other people understand, I think, just how dependent modern society is on the correct placing of mundane arithmetic operators or the appropriate invocation of variable references in obscure lines of old program code.  No programmers, in my experience, took less than seriously, for example, the threat of the Millenium Bug, although lots of people who are not programmers still think it was a threat without substance, or even a scam.

Below I have re-typed the article where first I read about this, as I can find no reference elsewhere on the web.

Faulty software may close more nuclear plants

(from Australasian Computerworld, 18 May 1979, pages 1 and 15).

Washington, DC. – The Nuclear Regulatory Commission (NRC) in the US may soon order more shutdowns of nuclear plants if it finds the design of their piping relies on invalid computer algorithms.

The commission is completing a study [page-break] to determine whether earthquakes could rupture the computer-designed piping of active US nuclear plants as well as those under construction.  In March, the commission ordered five plants in the eastern US to cease operation after an error was discovered in their design software.

The study was initiated following an anonymous phone call last month from an individual who reportedly told the NRC that many other plants were designed or are being designed with similarly flawed routines.  As a result, the commission ordered all 70 licensed plants and the 92 granted construction permits to declare whether they rely on any of three algebraic summation methods.

The water to cool reactor cores in the five suspended plants ran through pipes with tolerances far below NRC standards because of an algebraic summation routine subtracted, rather than added, stress figures.

Nuclear energy experts consider reliable reactor piping a critical safety factor.  A reactor core overheats if not enough water circulates around its radioactive rods to carry heat away.  Pipe ruptures or pump failures would thus induce core overheating that, if unchecked by reserve cooling systems, might force the reactor to discharge dangerous radiation.

NRC inspectors may order more shutdowns if they find other plants in violation of piping tolerance requirements, a spokesman said.  Their decisions will be based on responses to a general bulletin to holders of licences and construction permits.




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