How the Dimension of Space Affects the Products of Pre-Biotic Evolution: The Spatial Population Dynamics of Structural Complexity and The Emergence of Membranes

We show that autocatalytic networks of epsilon-machines and their population dynamics differ substantially between spatial (geographically distributed) and nonspatial (panmixia) populations. Generally, regions of spacetime-invariant autocatalytic networks---or domains---emerge in geographically distributed populations. These are separated by functional membranes of complementary epsilon-machines that actively translate between the domains and are responsible for their growth and stability. We analyze both spatial and nonspatial populations, determining the algebraic properties of the autocatalytic networks that allow for space to affect the dynamics and so generate autocatalytic domains and membranes. In addition, we analyze populations of intermediate spatial architecture, delineating the thresholds at which spatial memory (information storage) begins to determine the character of the emergent auto-catalytic organization.Comment: 9 pages, 7 figures, 2 tables; http://cse.ucdavis.edu/~cmg/compmech/pubs/ss.ht

Defrauding the Public Interest: A Critical Examination of Reengineered Audit Processes and the Likelihood of Detecting Fraud

In the past few years, most of the major international public accounting firms have reengineered their audit processes to improve the cost effectiveness of completing an audit and to focus on value-added services for clients. The reengineered audit processes generally focus on a client’s business processes and the information systems used by the client to generate financial information. In essence, the new audit approaches deemphasize direct testing of the underlying transactions and account balances. Such an approach emphasizes analytical procedures as the main source of substantive evidence. During this same time period, however, the profession (through the AICPA) explicitly acknowledged the profession’s responsibility for fraud detection. The main premise of this paper is that the increased emphasis on systems assessments is at odds with the profession’s position regarding fraud detection because most material frauds originate at the top levels of the organization, where controls and systems are least prevalent and effective. As such, the profession may be paying lip service to fraud detection, while at the same time changing the audit process in a manner that is less effective at detecting the most common frauds

An Economic Analysis of Property Rights in Information: Justifications and Problems of Exclusive Rights, Incentives to Generate Information, and the Alternative of a Government-Run Reward System

This article examines and questions the traditional justifications for intellectual property (I.P.) rights in America (focusing on copyright and patent law), and explores incentives necessary to induce the creation of these works of information. I conclude that changes are needed to I.P. law in order to best foster society\u27s dual goals of 1) promoting incentives to create I.P. works (such as currently patented drugs), while also 2) maximizing distribution of those products to all consumers who would stand to gain (and not merely those who can afford the monopoly price charged). Hence, I suggest the creation of a Government-Run Reward System to best serve both of society\u27s goals: incentives distribution. Under the reward system, innovators would be paid directly by the government for their intellectual property creations. In turn, their works would pass immediately into the public domain so that they are freely reproducible and distributable at their marginal cost of production (rather than the monopoly price which prevails under patent and copyright law today). In its ideal form, the reward system thereby allows for both socially optimal creation and distribution of intellectual property works, eliminating the deadweight social loss that plagues us today

The Finite-Sample E ects of VAR Dimensions on OLS Bias, OLS Variance, and Minimum MSE Estimators

Vector autoregressions (VARs) are important tools in time series analysis. However, relatively little is known about the nite-sample behaviour of parameter estimators. We address this issue, by investigating ordinary least squares (OLS) estimators given a data generating process that is a purely nonstationary rst-order VAR. Speci cally, we use Monte Carlo simulation and numerical optimization to derive response surfaces for OLS bias and variance, in terms of VAR dimensions, given correct speci cation and several types of over-parameterization of the model: we include a constant, and a constant and trend, and introduce excess lags. We then examine the correction factors that are required for the least squares estimator to attain minimum mean squared error (MSE). Our results improve and extend one of the main nite-sample multivariate analytical bias results of Abadir, Hadri and Tzavalis (Econometrica 67 (1999) 163), generalize the univariate variance and MSE ndings of Abadir (Economics Letters 47 (1995) 263) to the multivariate setting, and complement various asymptotic studies.Finite-sample bias, Monte Carlo simulation, nonstationary time series, response surfaces, vector autoregression.

CFRP truss for the CCAT 25 m diameter submillimeter-wave telescope

CCAT will be a 25 m diameter submillimeter-wave telescope that will operate inside a dome located on Cerro Chajnantor in the Atacama Desert. The telescope must have high aperture efficiency at a wavelength of 350 microns and good performance out to a wavelength of 200 microns. A conceptual design for a carbon fiber reinforced plastic (CFRP) truss and primary reflector support truss has been developed. This design yields a telescope with a net �½ wave front error of <10 microns using a lookup table to adjust the segment actuators to compensate for gravitational deflections. Minor corrections may be required to compensate for the expected 20 C temperature excursions. These can be handled using a coarse lookup table

Climate controls on temporal variability of methane flux from a poor fen in southeastern New Hampshire: Measurement and modeling

Three scales of temporal variability were present in methane (CH4) flux data collected during a 2.5 year (mid-1990–1992) study at a small, poor fen in southeastern New Hampshire. (1) There was a strong seasonality to the fluxes (high in summer); monthly average fluxes range from 21.4 mg CH4 m−2 d−1 (February 1992) to 639.0 mg CH4 m−2 d−1 (July 1991). Annual fluxes were 68.8 g CH4 m−2 (1991) and 69.8 g CH4 m−2 (1992). (2) There was interannual variability; distribution of flux intensity was very different from 1991 to 1992, particularly the timing and rapidity of the onset of higher fluxes in the spring. (3) There was a high degree of variability in CH4 flux during the warm season; four successive weekly flux rates in July 1991 were 957, 1044, 170, and 491 mg CH4 m−2 d−1. Fluxes were correlated with peat temperature (r2=0.44) but only weakly with depth to water table (r2 = 0.14 for warm season data). Warm season fluxes appeared to be suppressed by rainstorms. Along with methane flux data we present an analysis of this temporal variability in flux, using a peatland soil climate model developed for this site. The model was driven by daily air temperature, precipitation, and net radiation; it calculated daily soil temperature and moisture profiles, water table location, and ice layer thickness. Temperature profiles were generally in good agreement with field data. Depth to water table simulations were good in 1992, fair in 1990, and poor in the summer of 1991. Using model-simulated peat climate and correlations to methane flux developed from the field data, simulated methane fluxes exhibited the same three modes of temporal variability that were present in the field flux data, though the model underestimated peak fluxes in 1990 and 1991. We conclude that temporal variability in flux is significantly influenced by climate/weather variability at all three scales and that rainfall appears to suppress methane flux for at least several days at this site

Intrinsic fantasy: motivation and affect in educational games made by children

The concept of intrinsic fantasy has been considered central to the aim of usefully applying the positive affect of computer games to learning. Games with intrinsic fantasy are defined as having “an integral and continuing relationship with the instructional content being presented”, and are claimed as “more interesting and more educational” than extrinsic fantasy games [1]. Studies of children making educational games have shown they usually create extrinsic games for curriculum learning content. In this study, children were encouraged to create non-curriculum games, more easily distanced from the extrinsic preconceptions of formal schooling. Forty, 7-11 year olds took part in this study (17 boys and 23 girls), designing and making their own games at an after-school club. Despite non-curriculum learning content, no more intrinsic games were created than in previous studies. The children failed to create their own pedagogical models for non-curriculum content and did not see the educational value of intrinsic fantasy games. The implications for transfer and learning in intrinsic games are discussed whilst the definition of intrinsic fantasy itself is questioned. It is argued that the integral relationship of fantasy is unlikely to be the most critical means of improving the educational effectiveness of digital games

Detecting and predicting spatial and interannual patterns of temperate forest springtime phenology in the eastern U.S.

We performed a diagnostic analysis of AVHRR-NDVI and gridded, temperature data for the deciduous forests of the eastern U.S., calibrating temperature accumulation model with satellite data for 1982–1993. The model predicts interannual variability in onset date based upon year-to-year changes in springtime temperature. RMS error over the period ranges from 6.9 days in the northern portion of the domain to 10.7 days in the south. The analysis revealed a relationship between temperature accumulation and satellite derived onset date (rank correlation = 0.31–0.62). The required temperature accumulation threshold can be expressed as a function of mean temperature (R2 of 0.90) to facilitate predictive analysis of phenological onset, or when remote sensing data are unavailable

An automated tool for the design and assessment of space systems

Space systems can be characterized as both large and complex but they often rely on reusable subcomponents. One problem in the design of such systems is the representation and validation of the system, particularly at the higher levels of management. An automated tool is described for the representation, refinement, and validation of such complex systems based on a formal design theory, the Theory of Plausible Design. In particular, the steps necessary to automate the tool and make it a competent, usable assistant, are described