399 research outputs found
Rationalizing the UTMS spectrum bids: the case of the UK auction
This paper considers bidder behaviour in the United Kingdomâs UMTS spectrum
auction. Evidence is reviewed which shows that some bidders in this auction did
not bid straightforwardly in accordance with fixed valuations of the licenses. We
go on to consider more speculative hypotheses about biddersâ behaviour, such as
the hypotheses that bidders revised their valuations in the light of other biddersâ
behaviour, or that biddersâ valuations of licenses depended on which other companies
appeared likely to win a license. We find weak evidence in favor of some of these
hypotheses, but no hypothesis is supported by strong direct evidence. We conclude
that the rationalization of bidding in the United Kingdomâs UMTS auction remains
problematic. As a consequence we are cautious regarding the success of the auction
in achieving an efficient allocation of licenses
Coupled Replicator Equations for the Dynamics of Learning in Multiagent Systems
Starting with a group of reinforcement-learning agents we derive coupled
replicator equations that describe the dynamics of collective learning in
multiagent systems. We show that, although agents model their environment in a
self-interested way without sharing knowledge, a game dynamics emerges
naturally through environment-mediated interactions. An application to
rock-scissors-paper game interactions shows that the collective learning
dynamics exhibits a diversity of competitive and cooperative behaviors. These
include quasiperiodicity, stable limit cycles, intermittency, and deterministic
chaos--behaviors that should be expected in heterogeneous multiagent systems
described by the general replicator equations we derive.Comment: 4 pages, 3 figures,
http://www.santafe.edu/projects/CompMech/papers/credlmas.html; updated
references, corrected typos, changed conten
Single-mitosis dissection of acute and chronic DNA mutagenesis and repair
How chronic mutational processes and punctuated bursts of DNA damage drive evolution of the cancer genome is poorly understood. Here, we demonstrate a strategy to disentangle and quantify distinct mechanisms underlying genome evolution in single cells, during single mitoses and at single-strand resolution. To distinguish between chronic (reactive oxygen species (ROS)) and acute (ultraviolet light (UV)) mutagenesis, we microfluidically separate pairs of sister cells from the first mitosis following burst UV damage. Strikingly, UV mutations manifest as sister-specific events, revealing mirror-image mutation phasing genome-wide. In contrast, ROS mutagenesis in transcribed regions is reduced strand agnostically. Successive rounds of genome replication over persisting UV damage drives multiallelic variation at CC dinucleotides. Finally, we show that mutation phasing can be resolved to single strands across the entire genome of liver tumors from F1 mice. This strategy can be broadly used to distinguish the contributions of overlapping cancer relevant mutational processes
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Cold Air Distribution in Office Buildings: Technology Assessment for California
This paper presents the results of a study to assess the current state of practice, and energy and operating cost implications of cold air distribution in California, and to identify the key research needs for the continued development of this technology in new commercial buildings in the state. Whole-building energy simulations were made to compare the energy performance of a prototypical office building in three California climates using conventional and cold air distribution, with and without ice storage, to show the impacts of load shifting, energy use, and utility costs for three typical utility rate structures. The merits of economizers and fan-powered mixing boxes were also studied when used in conjunction with cold air delivery. A survey was conducted to assess the perceived strengths and limitations of this technology, perceived barriers to its widespread use, and user experience. The survey was based on interviews with consulting engineers, equipment manufacturers, researchers, utility representatives, and other users of cold air distribution technology. Selected findings from the industry survey are also discussed. Cold air distribution (CoAD) is found to always reduce fan energy use in comparison to conventional 55 F (13 C) air distribution systems, when conditioned air is delivered directly to the space (no fan-powered mixing boxes). Total building energy use for ice storage/CoAD systems was always higher than a well-designed conventional system, but significantly lower than a commonly-installed packaged system. When a favorable utility rate structure was applied, the load-shifting benefits of ice storage/CoAD systems produced the lowest annual operating costs of all system-plant configurations studied
The effects of changes in the order of verbal labels and numerical values on children's scores on attitude and rating scales
Research with adults has shown that variations in verbal labels and numerical scale values on rating scales can affect the responses given. However, few studies have been conducted with children. The study aimed to examine potential differences in childrenâs responses to Likert-type rating scales according to their anchor points and scale direction, and to see whether or not such differences were stable over time. 130 British children, aged 9 to 11, completed six sets of Likert-type rating scales, presented in four different ways varying the position of positive labels and numerical values. The results showed, both initially and 8-12 weeks later, that presenting a positive label or a high score on the left of a scale led to significantly higher mean scores than did the other variations. These findings indicate that different arrangements of rating scales can produce different results which has clear implications for the administration of scales with children
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