cssi/SciSciGPT-SciSciNet huggingface dataset:
ASSESSING THE OPTION VALUE OF THE OGALLALA AQUIFER IN TEXAS HIGH PLAINS: A CONTINGENT VALUATION APPROACH

Abstract The decline of the groundwater in the Ogallala Aquifer may create an uncertainty for water availability in the associated states in the future. Effective policy reforms are essential to determine efficient present and future use of water resources. Therefore, this study explores the option value for reducing current groundwater use to ensure the water availability in the Ogallala aquifer for future use. A double- bounded referendum format contingent valuation survey was carried out to investigate households’ preferences and the mean willingness to pay (WTP) of households for conserving the groundwater is empirically examined using a censored regression model. The estimated mean WTP to conserve one million acre feet of water for future use is $17.66 and the total willingness to pay is $28.96 million. The results indicate education and prior knowledge about the aquifer are significant determinants that are positively related to WTP whereas age is a significant factor that is negatively related to WTP in conserving the groundwater in the Ogallala Aquifer. This study provides policy makers with valuable information for building effective and sustainable policies, and the value estimates provided by this study will help future studies of groundwater use on the Texas High Plains.
Application of the Business Judgment Rule and Related Judicial Principles--Reflections from a Corporate Accountability Perspective

The author’s article for a symposium, The Role of Professionals in Corporate Governance, discusses judicial principles by a number of courts that permit boards of directors and management to improperly employ a relatively large number of procedures to insulate their actions from successful shareholder challenge. The principles permitting management to avoid shareholder scrutiny include the inveterate business judgment rule, the Burks v. Lasker special litigation committee scenario, certain limitations on the Goldberg v. Merzdor rationale, the true purpose cases, and the somewhat related disclosure of antisocial, unethical or unlawful policies rationale. The above list, although by no means exhaustive, will serve as the benchmark for this article.
Magnetic properties and electronic structure of manganese-based blue pigments: a high-frequency and -field EPR study.

A variety of new oxide-based materials based on hexagonal phase of YInO3 have been recently described. In some of these materials, the In(III) ions are substituted by Mn(III), which finds itself in a trigonal-bipyramidal (TBP) coordination environment. While YInO3 is colorless and YMnO3 is black, mixed systems YIn1–xMnxO3 (0.02 < x < 0.25) display intense blue color and have been proposed as novel blue pigments. Since the Mn(III) ion is paramagnetic, its presence imparts distinct magnetic properties to the whole class of materials. These properties were investigated by electron paramagnetic resonance (EPR) in its high-frequency and -field version (HFEPR), a technique ideally suited for transition metal ions such as Mn(III) that, in contrast to, for example, Mn(II), are difficult to study by EPR at (conventional) low frequency and field. YIn1–xMnxO3 with 0.02 < x < 0.2 exhibited high-quality HFEPR spectra up to room temperature that could be interpreted as arising from isolated S = 2 paramagnets. A simple ...
An Asteroseismology Explorer

In response to a NASA opportunity, a proposal has been made to study the concept of an Asteroseismology Explorer (ASE). The goal of the ASE would be to measure solar-like oscillations on many (perhaps hundreds) of stars during a 1-year mission, including many members of open clusters. We describe this proposal's observational goals, a strawman technical approach, and likely scientific rewards.
Aerosol first indirect effects on non‐precipitating low‐level liquid cloud properties as simulated by CAM5 at ARM sites

[1] We quantitatively examine the aerosol first indirect effects (FIE) for non-precipitating low-level single-layer liquid phase clouds simulated by the Community Atmospheric Model version 5 (CAM5) running in the weather forecast mode at three DOE Atmospheric Radiation Measurement (ARM) sites. The FIE is quantified in terms of a relative change in cloud droplet effective radius for a relative change in accumulation mode aerosol number concentration under conditions of fixed liquid water content (LWC). CAM5 simulates aerosol-cloud interactions reasonably well for this specific cloud type, and the simulated FIE is consistent with the long-term observations at the examined locations. The FIE in CAM5 generally decreases with LWC at coastal ARM sites, and is larger by using cloud condensation nuclei rather than accumulation mode aerosol number concentration as the choice of aerosol amount. However, it has no significant variations with location and has no systematic strong seasonal variations at examined ARM sites.
Systematic Measurement Errors

Nature, origin, and treatment of systematic errors in measurements and calibrations are discussed. It is shown how systematic errors can vary, how random errors under one set of conditions will become systematic errors under another set of conditions an..
Notes on topological insulators

This paper is a survey of the ℤ2-valued invariant of topological insulators used in condensed matter physics. The ℤ-valued topological invariant, which was originally called the TKNN invariant in physics, has now been fully understood as the first Chern number. The ℤ2 invariant is more mysterious; we will explain its equivalent descriptions from different points of view and provide the relations between them. These invariants provide the classification of topological insulators with different symmetries in which K-theory plays an important role. Moreover, we establish that both invariants are realizations of index theorems which can also be understood in terms of condensed matter physics.
Metric Entropy of Homogeneous Spaces

For a precompact subset K of a metric space and e > 0, the covering number N(K, e) is defined as the smallest number of balls of radius e whose union covers K . Knowledge of the metric entropy, i.e., the asymptotic behaviour of covering numbers for (families of) metric spaces is important in many areas of mathematics (geometry, functional analysis, probability, coding theory, to name a few). In this paper we give asymptotically correct estimates for covering numbers for a large class of homogeneous spaces of unitary (or orthogonal) groups with respect to some natural metrics, most notably the one induced by the operator norm. This generalizes the author’s earlier results concerning covering numbers of Grassmann manifolds; the generalization is motivated by applications to noncommutative probability and operator algebras. The argument uses a characterization of geodesics in U(n) (or SO(m)) for a class of non-Riemannian Finsler metric structures.
Detection of Orthogonal Interval Relations

The complete set R of orthogonal temporal interactions between pairs of intervals, formulated by Kshemkalyani, allows the detailed specification of the manner in which intervals can be related to one another in a distributed execution. This paper presents a distributed algorithm to detect whether pre-specified interaction types between intervals at different processes hold. Specifically, for each pair of processes i and j, given a relation ri, j from the set of orthogonal relations R, this paper presents a distributed (on-line) algorithm to determine the intervals, if they exist, one from each process, such that each relation ri, j is satisfied for that (i, j) process pair. The algorithm uses O(n min(np, 4mn)) messages of size O(n) each, where n is the number of processes, m is the maximum number of messages sent by any process, and p is the maximum number of intervals at any process. The average time complexity per process is O(min(np, 4mn)), and the total space complexity across all the processes is min(4pn2 - 2np, 10mn2).
Fission or fusion for Mars missions: Expectations and challenges

Abstract A fission based system in the form of the Gas Core Nuclear Rocket (GCR) and a laser-driven inertial fusion system that utilizes a self-generated magnetic field (MICF) are compared as potential propulsion systems for manned planetary travel. The first generates thrust by a hydrogen propellant that is heated by radiation emitted from a critical reactor with a uranium fuel in plasma form, to take advantage of high achievable temperatures. The fusion system produces attractive propulsion characteristics through energy magnification of a hot hydrogenous plasma which is guided by a magnetic nozzle that allows thermal energy to be converted into thrust. Although both systems are capable of producing several thousand seconds of specific impulse, and tens to hundreds of kilonewtons of thrust, each faces some formidable physics and engineering problems that must be addressed if they are to become viable propulsion systems. With the aid of an appropriate set of fluid and plasma equations, we assess the dynamics of each system and identify those issues that could detract from their performance. In the case of GCR, thermal hydraulic considerations reveal deterioration of propulsive capability when wall heat flux limitations and turbulent mixing are taken into account. Moreover, hydrodynamics and acoustic instabilities could also adversely affect its performance, although they may be amenable to stabilization by magnetic fields. For MICF, large energy multiplication at modest input laser energies appears to be a major concern, but if anti-hydrogen can be used to initiate the fusion reactions, this concept can be truly an outstanding propulsion device.
Jet Quenching and Correlations

This article reviews recent advances in our understanding of the experimental aspects of jet-quenching and correlations in relativistic heavy-ion collisions at RHIC and LHC. Emphasis is put on correlation measurements, namely jet-like correlations with anisotropic flow subtraction in heavy-ion collisions and long-range pseudorapidity correlations in small systems. Future path on correlation studies is envisioned which may elucidate jet–medium interactions and the properties of the hot dense medium in QCD.
A Policy of Strategic Petroleum Market Reserves

Unexpected price spikes in petroleum can lead to instability in markets and have a negative economic effect on sectors which rely on petroleum consumption. Sudden rises in the price of petroleum do not have to be long-term to cause negative, cascading impacts across the economy. Firms which make futures purchases or hedge against a higher price during a price spike can become insolvent when the price spike deflates. A policy is needed to buffer short-term perturbations in the petroleum market to avoid short-term price spikes. This study looks at the effects of implementing a Strategic Petroleum Market Reserve within a multi-agent Nation-State model which would utilize trading bands to determine when to buy and sell petroleum reserves. Our analysis indicates that the result of implementing this policy is a more stable petroleum market during conditions of resource scarcity.
Extending the TPTP language to higher-order logic with automated parser generation

A stable proposal for extending the first-order TPTP (Thousands of Problems for Theorem Provers) language to higher-order logic, based primarily on lambda-calculus expressions, is presented. The purpose of the system is to facilitate sharing of theorem-proving problems in higher-order logic among many researchers. Design goals are discussed. BNF2, a new specification language, is presented. Unix/Linux scripts translate the specification document into a lex scanner andyacc parser.
State-space abstraction for anytime evaluation of probabilistic networks

One important factor determining the computational complexity of evaluating a probabilistic network is the cardinality of the state spaces of the nodes. By varying the granularity of the state spaces, one can trade off accuracy in the result for computational efficiency. We present an anytime procedure for approximate evaluation of probabilistic networks based on this idea. On application to some simple networks, the procedure exhibits a smooth improvement in approximation quality as computation time increases. This suggests that state-space abstraction is one more useful control parameter for designing real-time probabilistic reasoners.
A novel Gaussian-Sinc mixed basis set for electronic structure calculations

A Gaussian-Sinc basis set methodology is presented for the calculation of the electronic structure of atoms and molecules at the Hartree–Fock level of theory. This methodology has several advantages over previous methods. The all-electron electronic structure in a Gaussian-Sinc mixed basis spans both the “localized” and “delocalized” regions. A basis set for each region is combined to make a new basis methodology—a lattice of orthonormal sinc functions is used to represent the “delocalized” regions and the atom-centered Gaussian functions are used to represent the “localized” regions to any desired accuracy. For this mixed basis, all the Coulomb integrals are definable and can be computed in a dimensional separated methodology. Additionally, the Sinc basis is translationally invariant, which allows for the Coulomb singularity to be placed anywhere including on lattice sites. Finally, boundary conditions are always satisfied with this basis. To demonstrate the utility of this method, we calculated the ground state Hartree–Fock energies for atoms up to neon, the diatomic systems H2, O2, and N2, and the multi-atom system benzene. Together, it is shown that the Gaussian-Sinc mixed basis set is a flexible and accurate method for solving the electronic structure of atomic and molecular species.
An oligopoly electricity competition model with probabilistic inflow & demand representations

The paper presents a Nash-Cournot equilibrium model for analyzing wholesale electricity market competition among generation companies owning a mixture of hydrothermal power generation facilities. The problem is formulated as a set of individual profit maximization models and solved using the mixed complementarity programming (MCP) method. The impact of strategic behavior by both hydro and thermal generation owners on competition is investigated. The model accounts for uncertainty in inflow and demand via a probabilistic method coupled with a probability space reduction technique for large problems. The results show that the algorithm proposed in this paper is efficient and robust.
Location privacy in mobile computing environments

In general, privacy can be viewed as the right to be left alone when desired (solitude), the right to remain anonymous (anonymity), and the right to confidentiality (secrecy of information). More specifically, location privacy is “the ability to prevent other parties from learning one’s current or past locations”. In this paper, we focus on two primitives that make up location privacy: identity information and location information. Identity information has to do with the static attributes and characteristics that uniquely identify a person. Information about an individual’s identity can also be inferred based upon their location at various times (in other words, their activities can give away identity information). The other type of information upon which we will focus, location information, deals specifically with the whereabouts of an individual or group. We will also describe location-aware applications and services and their relationship with location privacy.
Scheduling Periodic Real-Time Tasks with Heterogeneous Reward Requirements

We study the problem of scheduling periodic real-time tasks which have individual minimum reward requirements. We consider situations where tasks generate jobs that can be provided arbitrary service times before their deadlines, and obtain rewards based on the service times received by the jobs of the task. We show that this model is compatible with the imprecise computation models and the increasing reward with increasing service models. In contrast to previous work on these models, which mainly focus on maximizing the total reward in the system, we additionally aim to fulfill different reward requirements by different tasks. This provides better fairness and also allows fine-grained tradeoff between tasks. We first derive a necessary and sufficient condition for a system with reward requirements of tasks to be feasible. We next obtain an off-line feasibility optimal scheduling policy. We then study a sufficient condition for a policy to be feasibility optimal or achieve some approximation bound. This condition serves as a guideline for designing on-line scheduling policy and we obtain a greedy policy based on it. We prove that the on-line policy is feasibility optimal when all tasks have the same periods, and also obtain an approximation bound for the policy under general cases. We test our policies in comparative simulations.
A definition and graphical representation for causality

We present a precise definition of cause and effect in terms of a fundamental notion called unresponsiveness. Our definition is based on Savage's (1954) formulation of decision theory and departs from the traditional view of causation in that our causal assertions are made relative to a set of decisions. An important consequence of this departure is that we can reason about cause locally, not requiring a causal explanation for every dependency. Such local reasoning can be beneficial because it may not be necessary to determine whether a particular dependency is causal to make a decision. Also in this paper, we examine the graphical encoding of causal relationships. We show that influence diagrams in canonical form are an accurate and efficient representation of causal relationships. In addition, we establish a correspondence between canonical form and Pearl's causal theory.
Guaranteed pre-tagging for the Brill tagger

This paper describes and evaluates a simple modification to the Brill Part-of-Speech Tagger. In its standard distribution the Brill Tagger allows manual assignment of a part-of-speech tag to a word prior to tagging. However, it may change it to another tag during processing. We suggest a change that guarantees that the pre-tag remains unchanged and ensures that it is used throughout the tagging process. Our method of guaranteed pre-tagging is appropriate when the tag of a word is known for certain, and is intended to help improve the accuracy of tagging by providing a reliable anchor or seed around which to tag.
Has Globalization Eroded Labor’s Share? Some Cross-Country Evidence

In recent years, economists and other social scientists have devoted extensive research efforts to understanding the widening wage gap between high-skill and low-skill workers. This paper focuses on a slightly different question: how has globalization affected the relative share of income going to capital and labor? Using a panel of over one hundred countries, this paper analyses trends in labor shares and examines the relationship between shares and measures of globalization. Contrary to recent literature, the evidence suggests that labor shares are not constant over time. Over the 1960 to 2000 period, labor shares in poor countries fell, while shares in rich countries rose. These changes in labor shares are driven by changes in factor endowments and government spending, as well as by traditional measures of globalization, such as trade shares, exchange rate crises, movements in foreign investment, and capital controls. In particular, the results suggest that rising trade shares and exchange rate crises reduce labor’s share, while increasing capital intensity, capital controls and government spending increase labor’s share.
Parallel Deterministic Neutron Transport with AMR

AMTRAN, a one, two and three dimensional Sn neutron transport code with adaptive mesh refinement (AMR) has been parallelized with MPI over spatial domains and energy groups and with threads over angles. Block refined AMR is used with linear finite element representations for the fluxes, which are node centered. AMR requirements are determined by minimum mean free path calculations throughout the problem and can provide an order of magnitude or more reduction in zoning requirements for the same level of accuracy, compared to a uniformly zoned problem.
Bundling subscription TV channels

Abstract I analyze a market, such as a subscription TV market, where multiple varieties of an excludable public good are traded in bundles Here bundling is not due to a producer's desire to extract consumers' surplus but due to economies of scope in distribution technology The paper studies the pricing and production decisions of a supplier as well as the impacts of certain regulations such as pure-bundling or pure-components pricing restrictions Findings of interest are as follows A profit-constrained welfare maximizer would use a pure-bundling price system when costs are low, and a mixed-bundling price system when costs are high A private monopolist produces too few varieties A pure-bundling restriction on a private monopolist may increase welfare and consumer surplus, but a pure-components restriction never increases them.
Report of a field experiment to improve communications in a product engineering department; the non-territorial office

A year-long investigation was undertaken to determine the impact, of a radical new scheme of office layout on work-related behavior, communication, and performance. The office layout under investig...
Content-centric computing in visual systems

The nature of computing has changed over the last four decades in almost all aspects. The progress in processing power and storage capacity is well known. Computer was an esoteric device in even sixties and seventies; now it is an indispensable component of many household appliances. In this paper we discuss two emerging concepts : Content-Centric Computing and Gestalt Vision. Content-centric computing is being developed to deal with the challenge of dealing with enormopus amount of multimedia data. Gestalt vision has been the dream that can now be realised using emerging computing and sensor technology.
Controlling linear networks with minimally novel inputs

In this paper, we propose a novelty-based index for quantitative characterization of the controllability of complex networks. This inherently bounded index describes the average angular separation of an input with respect to the past input history. We use this index to find the minimally novel input that drives a linear network to a desired state using unit average energy. Specifically, the minimally novel input is defined as the solution of a continuous time, non-convex optimal control problem based on the introduced index. We provide conditions for existence and uniqueness, and an explicit, closed-form expression for the solution. We support our theoretical results by characterizing the minimally novel inputs for an example of a recurrent neuronal network.
Theory of disk accretion onto supermassive black holes

Accretion onto supermassive black holes produces both the dramatic phenomena associated with active galactic nuclei and the underwhelming displays seen in the Galactic Center and most other nearby galaxies. I review selected aspects of the current theoretical understanding of black hole accretion, emphasizing the role of magnetohydrodynamic turbulence and gravitational instabilities in driving the actual accretion and the importance of the efficacy of cooling in determining the structure and observational appearance of the accretion flow. Ongoing investigations into the dynamics of the plunging region, the origin of variability in the accretion process, and the evolution of warped, twisted, or eccentric disks are summarized.
Racial Income Disparities and the Measurement of Segregation

Racial segregation in residential patterns remains pervasive in the United States. This persistence is usually attributed to some combination of neighborhood preferences over racial composition, discrimination in real estate and credit markets, and the effects of racial disparities in income. We propose a method for the decomposition of segregation measures into two components. One of these can be interpreted as the component of segregation that can be attributed to the effect of racial income disparities alone, while the other captures the combined effect of neighborhood preferences and discrimination. Applying the method to thirty major metropolitan areas, we find that the role played by racial income disparities in accounting for segregation is generally modest but varies significantly across cities.
Cognitive Ability and Post-Retirement Asset Decumulation

Post-retirement asset decumulation decisions are complex and may be affected by cognitive abilities. Estimating uncertainties such as life expectancy and medical costs, and incorporating them effectively into decumulation decisions may be especially difficult as retirees face age-related changes in cognition. This may result in rates of decumulation that are contradictory to the goals that motivated accumulation, leading to potentially large utility losses. We investigated the relevance of cognitive ability to asset decumulation decisions within our sample. We found that cognitive ability was a significant predictor of the rate of asset decumulation, and that those with lower levels of cognitive ability were decumulating at a significantly lower rate. We also showed that the level of cognitive ability influenced the effects of expected longevity, market returns, and medical costs. While the estimates for these factors were consistent between those with high and low cognitive ability, there were significant differences in how the estimates were incorporated into the asset decumulation decisions of the two groups.
Digital control of a rapid capacitor charger with sensor-less voltage feedback

This paper describes the implementation of a load voltage observer into the control algorithms of a Rapid Capacitor Charger controlled by a digital signal controller (DSC) with a fast DSP core. A hybrid peak current mode control algorithm with digital control of the PWM signal and high speed analog current sensing is used to control the inverter of the charger. The DSC controller keeps the current loop stable using adaptive slope compensation. In addition to providing fast adaptive digital control of the current loop, the DSC can perform additional functions such as estimation of the voltage level of the load capacitor. This avoids the cost, bandwidth limitations and insulation challenges of a conventional HV-sensor. To evaluate the performance of the load voltage observer, we measured the output voltage with a laboratory grade HV probe to establish a reference to test the results of the digital algorithm.
Volcanism on Io: A Comparison with Earth

Preface Introduction Part I. Io, 1610 to 1995: Galileo to Galileo: 1. Io, 1610-1979 2. Between Voyager and Galileo: 1979-95 3. Galileo at Io Part II. Planetary Volcanism: Evolution and Composition: 4. Io and Earth: formation, evolution, and interior structure 5. Magmas and volatiles Part III. Observing and Modeling Volcanic Activity: 6. Observations: thermal remote sensing of volcanic activity 7. Models of effusive eruption processes 8. Thermal evolution of volcanic eruptions Part IV. Galileo at Io: the Volcanic Bestiary: 9. The view from Galileo 10. The lava lake at Pele 11. Pillan and Tvashtar: lava fountains and flows 12. Prometheus and Amirani: Effusive activity and insulated flows 13. Loki Patera: Io's powerhouse 14. Other volcanoes and eruptions Part V. Volcanism on Io: The Global View: 15. Geomorphology: paterae, shields, flows and mountains 16. Volcanic plumes 17. Hot spots Part VI. Io after Galileo: 18. Volcanism on Io: a post-Galileo view 19. The future of Io observations Appendix 1 Appendix 2 References Index.
Representing Graph Metrics with Fewest Edges

We are given a graph with edge weights, that represents the metric on the vertices in which the distance between two vertices is the total weight of the lowest-weight path between them. Consider the problem of representing this metric using as few edges as possible, provided that new "steiner" vertices (and edges incident on them) can be added. The compression factor achieved is the ratio k between the number of edges in the original graph and the number of edges in the compressed graph. We obtain approximation algorithms for unit weight graphs that replace cliques with stars in cases where the cliques so compressed are disjoint, or when only a constant number of the cliques compressed meet at any vertex. We also show that the general unit weight problem is essentially as hard to approximate as graph coloring and maximum clique.
Multi-wavelength pulse source from continuum generated in dispersion-tailored fibers

We demonstrate a multi-wavelength pulse source based on spectrally glaring continuum generated in a dispersion-decreasing (DD) fiber.
Microprocessor specification in Hawk

Modern microprocessors require an immense investment of time and effort to create and verify, from the high level architectural design downwards. We are exploring ways to increase the productivity of design engineers by creating a domain specific language for specifying and simulating processor architectures. We believe that the structuring principles used in modern functional programming languages, such as static typing, parametric polymorphism, first class functions, and lazy evaluation provide a good formalism for such a domain specific language, and have made initial progress by creating a library on top of the functional language Haskell. We have specified the integer subset of an out of order, superscalar DLX microprocessor, with register renaming, a reorder buffer, a global reservation station, multiple execution units, and speculative branch execution. Two key abstractions of this library are the signal abstract data type (ADT), which models the simulation history of a wire, and the transaction ADT, which models the state of an entire instruction as it travels through the microprocessor.
On CRDAHA and finite general linear and unitary groups

We show a connection between Lusztig induction operators in finite general linear and unitary groups and parabolic induction in cyclotomic rational double affine Hecke algebras. Two applications are given: an explanation of a bijection result of Broue, Malle and Michel, and some results on modular decomposition numbers of finite general groups. 2010 AMS Subject Classification: 20C33 Dedicated to the memory of Robert Steinberg
Ultra High Energy Cosmic Rays: Observations and Theoretical Aspects

We present a brief introduction to the physics of Ultra High Energy Cosmic Rays (UHECRs), concentrating on the experimental results obtained so far and on what, from these results, can be inferred about the sources of UHECRs.
All-sky survey mission observing scenario strategy

This paper develops an observing strategy for space missions performing all-sky surveys, where a single spacecraft maps the celestial sphere subject to realistic constraints. The strategy is flexible, accommodates targeted observations of specific areas of the sky, and achieves the desired trade-off between survey goals. This paper focuses on missions operating in low Earth orbit with interactive and dynamic thermal and stray-light constraints due to the Sun, Earth, and Moon. The approach is applicable to broader mission classes, such as those that operate in different orbits or that survey the Earth. First, the instrument and spacecraft configuration is optimized to enable visibility of the targeted observations throughout the year. Second, a constraint-based strategy is presented for scheduling the observations throughout the year subject to a simplified subset of the constraints. Third, a heuristic-based scheduling algorithm is developed to assign the all-sky observations over short planning horizons. The constraint-based approach guarantees solution feasibility. The approach is applied to the proposed SPHEREx mission, which includes coverage of the north and south celestial poles, galactic plane, and a uniform coverage all-sky survey that maps the entire celestial sphere twice per year. Visualizations demonstrate how the all-sky survey achieves its redundancy requirements over time.
Revisiting the Edge of Chaos: Evolving Cellular Automata to Perform Computations

Author(s): Mitchell, Melanie; Hraber, Peter; Crutchfield, James P | Abstract: We present results from an experiment similar to one performed by Packard (1988), in which a genetic algorithm is used to evolve cellular automata (CA) to perform a particular computational task. Packard examined the frequency of evolved CA rules as a function of Langton's lambda parameter (Langton, 1990), and interpreted the results of his experiment as giving evidence for the following two hypotheses: (1) CA rules able to perform complex computations are most likely to be found near ``critical'' lambda values, which have been claimed to correlate with a phase transition between ordered and chaotic behavioral regimes for CA; (2) When CA rules are evolved to perform a complex computation, evolution will tend to select rules with lambda values close to the critical values. Our experiment produced very different results, and we suggest that the interpretation of the original results is not correct. We also review and discuss issues related to lambda, dynamical-behavior classes, and computation in CA. The main constructive results of our study are identifying the emergence and competition of computational strategies and analyzing the central role of symmetries in an evolutionary system. In particular, we demonstrate how symmetry breaking can impede the evolution toward higher computational capability.
Upstream dams and downstream water allocation: the case of the Hadejia-Jama'are floodplain, northern Nigeria.

[1] This paper models the economic and hydrological impacts of upstream water diversion on downstream floodplain activities. The model is illustrated and applied to the example of the Hadejia-Jama'are River Basin, northern Nigeria. Full implementation of all the upstream dams and large-scale irrigation schemes in the river basin would produce losses of US$20.2–20.9 million in present value terms in terms of flooplain agriculture, forestry, and fishing. The associated annual losses from declining groundwater levels in surrounding areas would be around $1.2 million for tube well irrigation and $4.76 million for domestic water consumption. The introduction of a regulated flooding regime for upstream dams would probably protect the groundwater recharge function of the downstream floodplain and reduce substantially the losses to agriculture, forestry, and fishing to around $15.4–16.5 million.
Mix-nets: factored mixtures of Gaussians in Bayesian networks with mixed continuous and discrete variables

Recently developed techniques have made it possible to quickly learn accurate probability density functions from data in low-dimensional continuous spaces. In particular, mixtures of Gaussians can be fitted to data very quickly using an accelerated EM algorithm that employs multiresolution kd-trees (Moore, 1999). In this paper, we propose a kind of Bayesian network in which low-dimensional mixtures of Gaussians over different subsets of the domain's variables are combined into a coherent joint probability model over the entire domain. The network is also capable of modeling complex dependencies between discrete variables and continuous variables without requiring discretization of the continuous variables. We present efficient heuristic algorithms for automatically learning these networks from data, and perform comparative experiments illustrating how well these networks model real scientific data and synthetic data. We also briefly discuss some possible improvements to the networks, as well as possible applications.
Chemical Abundance Inhomogeneities in Globular Cluster Stars

It is now clear that abundance variations from star-to-star among the light elements, particularly C, N, O, Na and Al, are ubiquitous within galactic globular clusters; they appear seen whenever data of high quality is obtained for a sufficiently large sample of stars within such a cluster. The correlations and anti-correlations among these elements and the range of variation of each element appear to be independent of stellar evolutionary state, with the exception that enhanced depletion of C and of O is sometimes seen just at the RGB tip. While the latter behavior is almost certainly due to internal production and mixing, the internal mixing hypothesis can now be ruled out for producing the bulk of the variations seen. We focus on the implications of our new data for any explanation invoking primordial variations in the proto-cluster or accretion of polluted material from a neighboring AGB star.
Disturbance, Succession, and Structural Development of an Upland Hardwood Forest on the Interior Low Plateau, Tennessee

ABSTRACT: An appreciation for the importance of structural complexity, combined with the acknowledgment that stands with complex structures are uncommon compared to pre-European settlement estimates, has led to a growing interest in restoring late-successional forests. The success of these projects is dependent upon our understanding of the variability of late-successional structure and the disturbance events that produced this structure. We quantified woody species composition, stand structure, canopy disturbance history, and Quercus establishment and canopy accession patterns to document processes that resulted in the structural conditions of an upland hardwood forest in Tennessee. The forest established in the mid-1800s and exhibited structural characteristics that were within the range of what has been reported from other late-successional forests in the region. The forest overstory was dominated by Quercus prinus, but Acer saccharum was the most abundant species. Quercus recruitment was continuous fr...
Should Zambia produce biodiesel from soybeans ? some insights from an empirical analysis

Facing a huge fiscal burden due to imports of entire petroleum despite the availability of a surplus of agricultural land to produce biofuels, Zambia, a country in Sub-Saharan Africa, has recently introduced a biofuel mandate. But, a number of questions, particularly those related to the economics of biofuels, have not been fully investigated yet. Using an empirical model this study analyzes the economics of meeting the biodiesel mandate through soybean feedstock. The study finds that meeting the biodiesel mandate with biodiesel from soybeans would reduce social welfare because the country's soybean imports would cost more than the expected reduction in petroleum imports. However, if Zambia increases its domestic soybean supply along with its capacity to convert soybean to biodiesel, as well as oil yield, soybean based biodiesel is likely to be welfare-beneficial, even if biodiesel prices are above diesel prices. The study also finds that under current market prices and transportation costs and constraints, the same amount of biodiesel can be produced most cost-effectively with a tax exemption. A blend mandate would be less cost effective, while a biodiesel production subsidy represents the least efficient policy option.
Cloning Voronoi diagrams via retroactive data structures

We address the problem of replicating a Voronoi diagram V(S) of a planar point set S by making proximity queries: 1. the exact location of the nearest site(s) in S 2. the distance to and label(s) of the nearest site(s) in S 3. a unique label for every nearest site in S. In addition to showing the limits of nearest-neighbor database security, our methods also provide one of the first natural algorithmic applications of retroactive data structures.
DESIGNING AN IF-THEN RULES-BASED ENSEMBLE OF HETEROGENEOUS BANKRUPTCY CLASSIFIERS: A GENETIC ALGORITHM APPROACH

This paper proposes a framework for an ensemble bankruptcy classifier that uses if-then rules to combine the outputs from a heterogeneous set of classifiers. A genetic algorithm GA induces the rules using an asymmetric, cost-sensitive fitness function that includes accuracy and misclassification costs. The GA-based ensemble classifier outperforms individual classifiers and ensemble classifiers generated by other methods. The results of the classifier are in the form of if-then rules. We apply the approach to a balanced dataset and an imbalanced dataset. Both are composed of firms subject to financial distress and cited in the US Securities and Exchange Commission's Accounting and Auditing Enforcement Releases. Copyright © 2014 John Wiley & Sons, Ltd.
The Comparative Law and Economics of Judicial Councils

In recent decades, many countries around the world have institutionalized judicial councils, institutions designed to enhance judicial independence and accountability. Our paper, the first comparative inquiry into this phenomenon, has two aims. First, we provide an economic theory of the formation of judicial councils and identify some of the dimensions along which they differ. Second, we discuss the national experience of several legal systems in light of our theory.
The evolution of a new discourse for vocational psychology

This paper traces the evolution of the ways in which I have been thinking and talking about vocational psychology in the course of my professional life. This evolution has proceeded through three phases characterized by three changes in language and discourse; from career to work, from work to work and relationship, and the elaboration of work to refer specifically to market work and personal care work. Implications of these changes are addressed.
Black Holes and the Phases of Brane Thermodynamics

Thermodynamics is a useful tool in analyzing the characteristic properties of a system of many degrees of freedom. The equation of state gives the density of states, as well as clues to the effective degrees of freedom and their interactions, at the characteristic energy scale set by the temperature. These lectures will try to convey the idea that brane thermodynamics is a useful way of organizing much of what we know about the duality between quantum gravity and nongravitational theories (often gauge field theories) which generalizes the AdS/CFT correspondence (see [1] for a review).
When do donors trust recipient country systems

The 2005 Paris Declaration on Aid Effectiveness sets targets for increased use by donors of recipient country systems for managing aid. The target is premised on a view that country systems are strengthened when donors trust recipients to manage aid funds, but undermined when donors manage aid through their own separate parallel systems. This study provides an analytical framework for understanding donors' decisions to trust or bypass country systems. Empirical tests are conducted using data from three OECD-DAC surveys designed to monitor progress toward Paris Declaration goals. Tests show that a donor's use of the recipient country's systems is positively related to: (1) the donor's share of aid provided to the recipient (a proxy for the donor's reputational stake in the country's development); (2) perceptions of corruption in the recipient country (a proxy for the trustworthiness or quality of the country's systems); and (3) public support for aid in the donor country (a proxy for the donor's risk tolerance). Findings are robust to corrections for potential sample selection, omitted variables or endogeneity bias.
Veto games: Spatial committees under unanimity rule

There exists a large literature on two-person bargaining games and distribution games (or divide-the-dollar games) under simple majority rule, where in equilibrium a minimal winning coalition takes full advantage over everyone else. Here we extend the study to an n-person veto game where players take turns proposing policies in an n-dimensional policy space and everybody has a veto over changes in the status quo. Briefly, we find a Nash equilibrium where the initial proposer offers a policy in the intersection of the Pareto optimal set and the Pareto superior set that gives everyone their continuation values, and punishments are never implemented. Comparing the equilibrium outcomes under two different agendas – sequential recognition and random recognition – we find that there are advantages generated by the order of proposal under the sequential recognition rule. We also provide some conditions under which the players will prefer to rotate proposals rather than allow any specific policy to prevail indefinitely.
Frozen-in Fractals All Around: Inferring the Large-Scale Effects of Small-Scale Magnetic Structure

The large-scale structure of the magnetic field in the solar corona provides the energy to power large-scale solar eruptive events. Our physical understanding of this structure, and hence our ability to predict these events, is limited by the type of data currently available. It is shown that the multifractal spectrum is a powerful tool to study this structure, by providing a physical connection between the details of photospheric magnetic gradients and current density at all size scales. This uses concepts associated with geometric measure theory and the theory of weakly differentiable functions to compare Ampere’s law to the wavelet-transform modulus maximum method. The Holder exponent provides a direct measure of the rate of change of current density across spatial size scales. As this measure is independent of many features of the data (pixel resolution, data size, data type, presence of quiet-Sun data), it provides a unique approach to studying magnetic-field complexity and hence a potentially powerful tool for a statistical prediction of solar-flare activity. Three specific predictions are provided to test this theory: the multifractal spectra will not be dependent on the data type or quality; quiet-Sun gradients will not persist with time; structures with high current densities at large size scales will be the source of energy storage for solar eruptive events.
A new reconstruction filter for undersampled light fields

This paper builds on previous research in the light field area of image-based rendering. We present a new reconstruction filter that significantly reduces the "ghosting" artifacts seen in undersampled light fields, while preserving important high-fidelity features such as sharp object boundaries and view-dependent reflectance. By improving the rendering quality achievable from undersampled light fields, our method allows acceptable images to be generated from smaller image sets. We present both frequency and spatial domain justifications for our techniques. We also present a practical framework for implementing the reconstruction filter in multiple rendering passes.
Ecotopia: an ecological framework for change management in distributed systems

Dynamic change management in an autonomic, service-oriented infrastructure is likely to disrupt the critical services delivered by the infrastructure. Furthermore, change management must accommodate complex real-world systems, where dependability and performance objectives are managed across multiple distributed service components and have specific criticality/value models. In this paper, we present Ecotopia, a framework for change management in complex service-oriented architectures (SOA) that is ecological in its intent: it schedules change operations with the goal of minimizing the service-delivery disruptions by accounting for their impact on the SOA environment. The change-planning functionality of Ecotopia is split between multiple objective-advisors and a system-level change-orchestrator component. The objective advisors assess the change-impact on service delivery by estimating the expected values of the Key Performance Indicators (KPIs), during and after change. The orchestrator uses the KPI estimations to assess the per-objective and overall business-value changes over a long time-horizon and to identify the scheduling plan that maximizes the overall business value. Ecotopia handles both external change requests, like software upgrades, and internal changes requests, like fault-recovery actions. We evaluate the Ecotopia framework using two realistic change-management scenarios in distributed enterprise systems.