Jack, 1999(2), 2000(3)
These are my favorites from 1999:
Brain-machine interfaces
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Barinaga. "Turning Thoughts Into Actions." beta1, #4.
Communication devices that translate thoughts into commands to operate
computers, driven by brain waves detected from outside the body or by
electrodes implanted in the brain, are now bring tested in paralyzed
patients. Recent research at the annual meeting of the Society for
Neuroscience suggests that more sophisticated devices allowing people to
operate a robotic arm by thought alone may not be far behind.
Wissenschaft, Sabe. "Artificial Neurons in Vivo." beta2, #5.
Cyborgs -- human/machine hybrids -- have long been the dream of science
fiction authors..and some military enthusiasts. More than ten years ago
some studies have been done about a heavily armored fighting suit that is
hydraulically controlled through some direct brain interface. The project
apparently died because the communication rate is too low and unreliable.
Today, ten years later we have a thought translation device -- which is
still very slow -- and some research into direct integration of artificial
and biological neurons.
Computational Finance
=====================
Farmer. "Physics of Finance." beta3, #2.
Farmer reviews some of the theoretical methods behind "econo-physics" and
computational finance. The central object of study is the log-return
function, which tells you how much you can expect an investment at a given
time will return a certain amount of time later. Already in the 1960s,
Benoit Mandelbrot and other recognized that log-return histories are better
described by fractal curves than by traditional statistical processes.
Today we know from millions of analyzed transactions that the story is a
little more complex: no low dimensional chaotic attractors appear to describe
the data, although nonlinearities (a precondition of chaos) are clearly
present. Instead of simple fractals, one needs multi-fractals to describe
the scaling properties of the data. In good physics tradition the econo-
physicists are not too shy to introduce new technical terms like "fat tails"
and even a "smile". Instead of econometric models, the simulations are
done based on models of economic agents. As a return of this theoretical
investment one seems to get a better understanding of phenomena like
"clustered volatility" and "information cascades".
Gopikrisnan, Plerou, Anaral, Meyer, Stanley. "Scaling of the distribution of
financial market indices." beta5, #11.
The distribution of fluctuations of the S&P500 index over a time scale t
is studied by analyzing three distinct databases. Database (i) contains
approximately 1,200,000 records, sampled at 1-min intervals, for the 13-year
period 1984-1996, database (ii) contains 868 daily records for the 35-year
period 1962-1996, and database (iii) contains 852 monthly records for the
71-year period 1926-1996. The probability distributions of returns over a
time scale t is computed, where t varies approximately over a factor of
104 -- from 1 min up to more than one month. It is found that the
distributions for t 4 d (1560 min) are consistent with a power-law asymptotic
behavior, characterized by an exponent 3, well outside the stable Levy
regime 0 << 2. Consistent results are discovered in the analysis of two
other financial market indices.
These are my favorites from 2000:
AI
==
2000.4, #5: Life and Evolution in Computers, Santa Fe Institute Working Papers
Can we build computers that are intelligent and alive? This question has
been on the minds of computer scientists since the dawn of the computer age
and remains a most compelling line of inquiry. Some would argue that the
question makes sense only if we put scare quotes around "intelligent" and
"alive," since we're talking about computers, after all, not biological
organisms..
Brain-Machine Interfaces
========================
2000.6, #7: Synchronization Properties of Brain Waves, PNAS
Electrical brain rhythms have traditionally been divided up into different
frequency bands that are associated with different mental states. Best known
among them are alpha rhythms in the 8-12 Hz range that are associated with a
relaxed resting state. Beta rhythms (12-30 Hz) as associated with alert
mental activity whereas gamma rhythms (30-70 Hz) have recently found a lot
of attention in connection with the "binding process" during e.g. the
perception of an object where different features are integrated into a
coherent structure. There have been a numbe of theoretical models to explain
the synchronization (and de-synchronization) of the tens of thousans of
neurons that have to act together in order to be observable as an electrical
EEG signal. Kopell et al study a simplified neuronal model to demonstrate
how different mechanisms can give rise to different rhythms.
Computational Finance
=====================
2000.15, #5: The Nasdaq Crash of April 2000, arXiv
The Nasdaq fell another 10% on Friday the 14th of April 2000, signaling the
end of a remarkable speculative high-tech bubble starting in spring of 1997.
The closing of the Nasdaq at 3321 corresponds to a total loss of over 35%
since its all-time high of 5133 on the 10th of March 2000. Similarities to
the speculative bubble preceding the infamous crash of October 1929 are
quite striking: The belief in what was coined a "New Economy" both in 1929
and presently made the share-prices of companies with three digits price to
earning ratios soar. Furthermore, these two speculative bubbles, as well as
others, both nicely fit into the quantitative framework proposed by the
authors in a series of recent papers.