Archway Commencement Issue, May 18, 1991.

1991 Archway Commencement Issu

A Computational View of Market Efficiency

We propose to study market efficiency from a computational viewpoint. Borrowing from theoretical computer science, we define a market to be \emph{efficient with respect to resources $S$} (e.g., time, memory) if no strategy using resources $S$ can make a profit. As a first step, we consider memory-$m$ strategies whose action at time $t$ depends only on the $m$ previous observations at times $t-m,...,t-1$. We introduce and study a simple model of market evolution, where strategies impact the market by their decision to buy or sell. We show that the effect of optimal strategies using memory $m$ can lead to "market conditions" that were not present initially, such as (1) market bubbles and (2) the possibility for a strategy using memory $m' > m$ to make a bigger profit than was initially possible. We suggest ours as a framework to rationalize the technological arms race of quantitative trading firms

High-Performance low-vcc in-order core

Power density grows in new technology nodes, thus requiring Vcc to scale especially in mobile platforms where energy is critical. This paper presents a novel approach to decrease Vcc while keeping operating frequency high. Our mechanism is referred to as immediate read after write (IRAW) avoidance. We propose an implementation of the mechanism for an Intel® SilverthorneTM in-order core. Furthermore, we show that our mechanism can be adapted dynamically to provide the highest performance and lowest energy-delay product (EDP) at each Vcc level. Results show that IRAW avoidance increases operating frequency by 57% at 500mV and 99% at 400mV with negligible area and power overhead (below 1%), which translates into large speedups (48% at 500mV and 90% at 400mV) and EDP reductions (0.61 EDP at 500mV and 0.33 at 400mV).Peer ReviewedPostprint (published version

Desiring and critiquing humanity/ability/personhood : disrupting the ability/disability binary

The authors take up the challenge of Goodley and Runswick-Cole’s call to dismantle the ability/disability binary such that those now called ‘disabled’ can unproblematically join the ranks of those who will be counted as human. Using the methodology of collective biography, the six authors explore their own memories of becoming abled, and find in those memories a similar pattern of desire for, and critique of, humanness that Goodley and Runswick-Cole found in the participants in their own study, participants who were categorised as intellectually disabled. We turn to post philosophies to further develop the vocabularies through which the meaning of human can be expanded to include those who are currently viewed as less-than-human or other-to-human in their difference from the norm. Points of interest: - In this article the authors use the research method of ‘collective biography’ to explore their first memories of how they became able, and were recognized as normal and human. - We work with childhood photos to help open up our memories. - We challenge the taken-for-granted division between the categories normal/abnormal, able/disabled. - We argue that everybody is different, and that we all change and become able in different ways. - We are all vulnerable and we all desire to belong in the same world, irrespective of the categories we are placed in

Bubble collisions and measures of the multiverse

To compute the spectrum of bubble collisions seen by an observer in an eternally-inflating multiverse, one must choose a measure over the diverging spacetime volume, including choosing an "initial" hypersurface below which there are no bubble nucleations. Previous calculations focused on the case where the initial hypersurface is pushed arbitrarily deep into the past. Interestingly, the observed spectrum depends on the orientation of the initial hypersurface, however one's ability observe the effect rapidly decreases with the ratio of inflationary Hubble rates inside and outside one's bubble. We investigate whether this conclusion might be avoided under more general circumstances, in particular placing the observer's bubble near the initial hypersurface. We find that it is not. As a point of reference, a substantial appendix reviews relevant aspects of the measure problem of eternal inflation.Comment: 24 pages, two figures, plus 16-page appendix with one figure; v2: minor improvements and clarifications, conclusions unchanged (version to appear in JCAP

Why Boltzmann Brains Are Bad

Some modern cosmological models predict the appearance of Boltzmann Brains: observers who randomly fluctuate out of a thermal bath rather than naturally evolving from a low-entropy Big Bang. A theory in which most observers are of the Boltzmann Brain type is generally thought to be unacceptable, although opinions differ. I argue that such theories are indeed unacceptable: the real problem is with fluctuations into observers who are locally identical to ordinary observers, and their existence cannot be swept under the rug by a choice of probability distributions over observers. The issue is not that the existence of such observers is ruled out by data, but that the theories that predict them are cognitively unstable: they cannot simultaneously be true and justifiably believed

The Utopian

The paper was concerned with the future of the social housing complex in Poplar, East London called Robin Hood Gardens designed, conceived and built in the late 60's by Alison and Peter Smithson. The project and publication centred on the possible future for the building through a series of articles and conceptual visions created by us as the authors

Archway Commencement Issue, May 2005

Archway 2005 Commencement Issu

Archway Commencement Issue, May 1995

1995 Archway Commencement Issu