cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Intraoperative Liver Surface Completion with Graph Convolutional VAE
Creators: name: Foti, Simone
name: Koo, Bongjin
name: Dowrick, Thomas
name: Ramalhinho, Joao
name: Allam, Moustafa
name: Davidson, Brian
name: Stoyanov, Danail
name: Clarkson, Matthew J.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: In this work we propose a method based on geometric deep learning to predict the complete surface of the liver, given a partial point cloud of the organ obtained during the surgical laparoscopic procedure. We introduce a new data augmentation technique that randomly perturbs shapes in their frequency domain to compensate the limited size of our dataset. The core of our method is a variational autoencoder (VAE) that is trained to learn a latent space for complete shapes of the liver. At inference time, the generative part of the model is embedded in an optimisation procedure where the latent representation is iteratively updated to generate a model that matches the intraoperative partial point cloud. The effect of this optimisation is a progressive non-rigid deformation of the initially generated shape. Our method is qualitatively evaluated on real data and quantitatively evaluated on synthetic data. We compared with a state-of-the-art rigid registration algorithm, that our method outperformed in visible areas.
Competition Effects of Supermarket Services
Creators: name: Bonanno, Alessandro
name: Lopez, Rigoberto A.
name: Bonanno, Alessandro
name: Lopez, Rigoberto A.
Publisher: name: Unknown
Year: 2007
Subjects: subject: Agribusiness
subject: retailing
subject: pricing
subject: milk
subject: supermarkets

description: This paper investigates the effect of in-store services on retail food prices, supermarket competition, and demand using fluid milk as a case study. It is shown that higher-service supermarkets charge higher milk prices essentially because of an increase in market power due to differentiation of service offering. Results show that different types of services impact milk prices differently, that upscale food-retailers face stronger competition in newer services, and that service competition results in a trade-off for the consumer between the attractiveness of the enhanced retail configuration and the increase in prices.
The planted $k$-factor problem
Creators: name: Sicuro, Gabriele
name: Zdeborová, Lenka
Publisher: name: arXiv
Year: 2020
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Discrete Mathematics (cs.DM)
subject: Probability (math.PR)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: We consider the problem of recovering an unknown $k$-factor, hidden in a weighted random graph. For $k=1$ this is the planted matching problem, while the $k=2$ case is closely related to the planted travelling salesman problem. The inference problem is solved by exploiting the information arising from the use of two different distributions for the weights on the edges inside and outside the planted sub-graph. We argue that, in the large size limit, a phase transition can appear between a full and a partial recovery phase as function of the signal-to-noise ratio. We give a criterion for the location of the transition.
description: 21 pages, 4 figures
An Anatomy of Moroccan Agricultural Trade
Creators: name: Li, NaiChia
name: Roe, Terry L.
name: Diao, Xinshen
name: Somwaru, Agapi
name: Li, NaiChia
name: Roe, Terry L.
name: Diao, Xinshen
name: Somwaru, Agapi
Publisher: name: Unknown
Year: 2007
Subjects: International Relations/Trade

description: Morocco is engaged in a number of economic reforms to better position the country's integration into world markets. Her agricultural sector is particularly important as its trade, GDP, and employment share are relatively large. We analyze Morocco's agricultural trade growth trends over the past 40 years (1962 - 2004) using SITC 4-digit bilateral agricultural trade data. The data are analyzed using the trend and cycles decomposition (TCD) approach and measurement of trade growth at the intensive and extensive margin. We find a high concentration of agriculture trade in both commodities and trading partners. Morocco has also lost export shares in EU to other EU countries in her top exporting commodities. Another finding suggests that agricultural export growth for Morocco was at the intensive rather than extensive margin. This posts a great challenge for Morocco if she is to expand trade at the extensive margin.
Investigation of Langdon effect on the stimulated backward Raman and Brillouin scattering
Creators: name: Qiu, Jie
name: Hao, Liang
name: Cao, Li Hua
name: Zou, Shiyang
Publisher: name: arXiv
Year: 2020
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: In a laser-irradiated plasma, the Langdon effect makes the electron energy distribution function (EEDF) tend to a super-Gaussian distribution, which has important influences on laser plasma instabilities. In this work, the influences of a super-Gaussian EEDF on the convective stimulated backward Raman scattering (SRS) and stimulated backward Brillouin scattering (SBS) are studied systematically for a wide range of typical plasma parameters in the inertial confinement fusion (ICF). Distinct behaviors are found for SRS and SBS in the variation trend of the peak spatial growth rate and the corresponding wavelength of the scattered light. Especially, the Langdon effect on the SBS in plasmas with different ion species and isotopes is analyzed in detail, and the parameter boundary for judging the variation trend of the peak spatial growth rate of SBS with the superGaussian exponent is presented for the first time. In certain plasma parameter region, it is found that the Langdon effect could enhance SBS in mixed plasma, which may attenuate the improvement in suppressing SBS by mixing low-Z ions into the high-Z plasma. These comprehension of Langdon effect on LPIs would contribute to a better understanding of SRS and SBS in experiments.
description: 15 figures
Limited Resource Families and Child Health Status: A Case Study in Montero, Bolivia
Creators: name: Martin, Marshall A.
name: Taulman, Lesley
name: Martin, Marshall A.
name: Taulman, Lesley
Publisher: name: Unknown
Year: 2007
Subjects: Health Economics and Policy

description: Child malnutrition is a problem that poses social and economic costs to individuals, households, communities, and nations, like Bolivia. Childhood malnutrition can be reduced through effective policy and health interventions such as those of the Consejo de Salud Rural Andino (CSRA) in Montero, Bolivia. The CSRA is a non-profit, private organization that operates three health care clinics in Montero, Bolivia. Low-income mothers and their children are provided with free or minimal-cost public health education and basic pre- and post natal medical services . Three separate clinic areas serve three different populations in terms of child nutritional status and demographic and socioeconomic characteristics. Effectiveness and priority intervention points for reducing childhood malnutrition can be identified by a thorough understanding of socio-economic and demographic characteristics as they relate to child nutrition status. Survey data were collected from 180 women with children under the age of five living in the CSRA clinic coverage area. Data focused on child health, nutrition, anthropometric data, and household socioeconomic and demographic characteristics. Multivariate regression analysis was used to explain child nutrition status as indicated by anthropometric indices. The regression models included child-specific, maternal, and household factors. Regression models were estimated for three anthropometric indices: weight-for-age, height-for-age, and weight-for-height. CSRA initiatives were found to have made a positive contribution to child and maternal health care. However, child malnutrition remains which is inversely associated with critical demographic and socioeconomic characteristics of the various households such as maternal education and household income and wealth.
FPGA-based High-order Finite Difference Algorithm for 2D Acoustic Wave Propagation Problems
Creators: name: Lu, Mi
Publisher: name: figshare
Year: 2021
Subjects: subject: 10399 Numerical and Computational Mathematics not elsewhere classified
subject: FOS: Mathematics

description: Finite Difference Time Domain (FDTD) method is the most commonly used numerical algorithm for simulating linear wave propagation phenomena in geophysics, electromagnetics, and aero- or marine acoustics applications. Unfortunately, evaluating time evolution for millions to trillions of discrete spatial points is computational intensive, especially when the geometrical size under study is much larger than the wavelength of excitations or long time integration is needed. In this paper, we proposed an FPGA-based hardware implementation to accelerate these simulation tasks. By adopting high-order temporal and spatial finite difference numerical algorithms along with efficient on-chip memory architecture, we alleviate the bandwidth bottleneck between the FPGA chip and onboard memories at the cost of increased computational burdens, which are absorbed effectively into the pipelined computing engine without speed penalty. The speed of our design implemented on Xilinx ML401 Virtex-4 evaluation platform is about 7~20 times faster than a pure software implementation of the same algorithm running on a 3.0GHz DELL workstation. Moreover, the desirable properties of simplicity and scalability make our design compatible with most commercial reconfigurable coprocessor platforms and correspondingly, the performance would be proportional to their available onboard memory bandwidth.
Half-metallic ferromagnetism with high magnetic moment and high Curie temperature in Co$_2$FeSi
Creators: name: Wurmehl, Sabine
name: Fecher, Gerhard H.
name: Ksenofontov, Vadim
name: Casper, Frederick
name: Stumm, Ullrich
name: Felser, Claudia
name: Lin, Hong-Ji
Publisher: name: arXiv
Year: 2005
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Co$_2$FeSi crystallizes in the ordered L2$_1$ structure as proved by X-ray diffraction and Mößbauer spectroscopy. The magnetic moment of Co$_2$FeSi was measured to be about $6μ_B$ at 5K. Magnetic circular dichroism spectra excited by soft X-rays (XMCD) were taken to determine the element specific magnetic moments of Co and Fe. The Curie temperature was measured with different methods to be ($1100\pm20$)K. Co$_2$FeSi was found to be the Heusler compound as well as the half-metallic ferromagnet with the highest magnetic moment and Curie temperature.
description: conference contribution, MMM2005
Prediction and optimization of surface waviness in wire and arc additive manufacturing using ANN+PSO/PSO hybrid model
Creators: name: Cheng, Jun
name: De Waele, Wim
Publisher: name: Zenodo
Year: 2023

description: This poster presents a novel hybrid model for the optimization and prediction of surface waviness of components produced by wire and arc additive manufacturing. It consists of an artificial neural network optimized by the rank-Gaussian particle swarm optimization (PSO) and combined with an RGPSO algorithm. The novelty is that RGPSO is not only used to optimize the hyperparameters of the ANN model improving its prediction performance, but also to solve the problem of optimizing surface waviness. Experimental data of waviness from literature are used to define training data, and the K-fold cross-validation strategy is applied to train, test, and validate the prediction model. The results indicate that the performance of the developed RGPSO/ANN model reaches a higher accuracy than a PSO/ANN model and an ANN model. The prediction errors of the RGPSO+ANN are within ±0.05 mm for all samples, while the PSO+ANN model has some errors that are outside of this range. The accuracy of the PSO/ANN prediction model is quantified as 0.019, 0.990, 0.013, and 3.46% in terms of RMSE, R^2, MAE, and MAPE. The RGPSO, PSO, and other optimization algorithms are applied to optimize the WAAM process parameters to reach the minimal value of waviness. The lowest value for waviness is obtained with the RGPSO algorithm and is equal to 0.1631 mm.
Testing for Complementarity and Substitutability among Multiple Technologies: The Case of U.S. Hog Farms
Creators: name: Yu, Li
name: Hurley, Terrance M.
name: Kliebenstein, James B.
name: Orazem, Peter F.
name: Yu, Li
name: Hurley, Terrance M.
name: Kliebenstein, James B.
name: Orazem, Peter F.
Publisher: name: Unknown
Year: 2007
Subjects: Farm Management
Productivity Analysis

description: The hypothetical distribution of multiple technology adoptions under the assumption that technologies are mutually independent is compared against the actual observed distribution of technology adoptions on hog farms. Combinations of technologies that occur with greater frequency than would occur under independence are mutually complementary technologies. Combinations that occur with less frequency are substitute technologies. This method is easily applied to simultaneous decisions regarding many technologies. We find that some technologies used in pork production are mutually substitutable for one another while others are complementary. However, as the number of bundled technologies increases, they are increasingly likely to be complementary with one another, even if subsets are substitutes when viewed in isolation. This finding suggests that farmers have an incentive to adopt many technologies at once. Larger farms and farms run by more educated operators are the most likely to adopt multiple technologies. Our findings suggest that the complementarity among technologies in large bundles is contributing to a form of returns to scale that is leading to increasing growth in average farm size.
Neutrality of Decoupled Payments in the Presence of Credit Market Imperfections
Creators: name: Monge-Arino, Francisco
name: Gonzalez-Vega, Claudio
name: Monge-Arino, Francisco
name: Gonzalez-Vega, Claudio
Publisher: name: Unknown
Year: 2007
Subjects: Agricultural Finance

description: Decoupled payments have emerged as an alternative to traditional agricultural subsidies that are coupled to production decisions, in order to minimize the distorting impacts of domestic agricultural policy. Economic theory suggests that, when farmers face imperfections in key markets such as that for financial services, even lump-sum subsidies may affect agricultural output. This paper explores these issues by developing and solving a deterministic dynamic optimization model for a credit-constrained representative corn farming household in the United States. The model is parameterized using data from the USDA's ARMS database. Simulations for different levels of DP and other parameters were conducted, and three effects on agricultural output stemming from DP were found: an expanding and temporary liquidity effect; an expanding and permanent credit supply effect; and a contracting and permanent land price effect. The magnitude and direction of the final net effect depends on several factors that require further empirical research.
Lattice cut-off effects and their reduction in studies of QCD thermodynamics at non-zero temperature and chemical potential
Creators: name: Hegde, P.
name: Karsch, F.
name: Laermann, E.
name: Shcheredin, S.
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: We clarify the relation between the improvement of dispersion relations in the fermion sector of lattice regularized QCD and the improvement of bulk thermodynamic observables. We show that in the infinite temperature limit the cut-off dependence in dispersion relations can be eliminated up to O(a^n) corrections, if the quark propagator is chosen to be rotationally invariant up to this order. In bulk thermodynamic observables this eliminates cut-off effects up to the same order at vanishing as well as non-vanishing chemical potential. We furthermore show, that in the infinite temperature, ideal gas limit the dependence of finite cut-off corrections on the chemical potential is given by Bernoulli polynomials which are universal as they do not depend on a particular discretization scheme. We explicitly calculate leading and next-to-leading order cut-off corrections for some staggered and Wilson fermion type actions and compare these with exact evaluations of the free fermion partition functions. This also includes the chirally invariant overlap and domain wall fermion formulations.
description: 19 pages, 7 plots
An Optimized Finite Difference Computing Engine on FPGAs
Creators: name: Lu, Mi
Publisher: name: figshare
Year: 2021
Subjects: subject: 10399 Numerical and Computational Mathematics not elsewhere classified
subject: FOS: Mathematics

description: Time domain or frequency domain Finite Difference (FD) methods are one of the most popular numerical modelling techniques in the solution of scientific and engineering problems. However, these simulations are still time-consuming and cannot be used routinely except in institutes that can afford the high cost of running and maintaining supercomputers or large PC-cluster systems. In this paper, we present an efficient implementation of FPGA-based FD computing engine using acoustic wave modeling problems as an example. Instead of following the formal high-order FD expressions with standard IEEE-754 compliant floating-point multipliers and adders, we propose a new class of optimized FD schemes, whose FD coefficients are optimized to be only a few binary bits so that much fewer Logic Cell (LC) resources or on-chip multipliers are needed without deteriorating numerical accuracy criterions. Furthermore, we simplify the implementation of following floating-point summations by group-alignment technology. A floating-point/fixed-point hybrid accumulator with similar relative and absolute rounding errors now replaces the conventional costly floating-point adder tree.
Magneto-optical study of magnetization reversal asymmetry in exchange bias
Creators: name: Tillmanns, A.
name: Oertker, S.
name: Beschoten, B.
name: Güntherodt, G.
name: Leighton, C.
name: Schuller, Ivan K.
name: Nogues, J.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The asymmetric magnetization reversal in exchange biased Fe/MnF$_{2}$ involves coherent (Stoner-Wohlfarth) magnetization rotation into an intermediate, stable state perpendicular to the applied field. We provide here experimentally tested analytical conditions for the unambiguous observation of both longitudinal and transverse magnetization components using the magneto-optical Kerr effect. This provides a fast and powerful probe of coherent magnetization reversal as well as its chirality. Surprisingly, the sign and asymmetry of the transverse magnetization component of Fe/MnF$_{2}$ change with the angle between cooling and measurement fields.
description: 9 pages, 3 figures
Halaski, K. / Herrenbrück W. (Hrsg.), Kirche - Konfession - Ökumene
Creators: name: Kemper, Claus
Publisher: name: Ökumenische Rundschau
Year: 2025

description: Ökumenische Rundschau, Bd. 22 Nr. 3 (1973): Ökumenische Rundschau, Band 22, Heft 3
Supplementary document for Decoupled Spectral Tuning for Multi-Band Perfect Absorption via Brillouin Zone-Folding Induced Quasi-BICs - 7438691.pdf
Creators: name: Jin, Rong
name: Huang, Lujun
name: Guo, Jiaoyang
name: Fu, Zhenchu
name: Zhang, Yukang
name: Yu, Feilong
name: Chen, Jin
name: Li, Guanhai
name: Chen, Xiaoshuang
name: Lu, Wei
Publisher: name: Optica Publishing Group
Year: 2025
Subjects: Uncategorized

description: Supplementary file
Dynamics and statistics of heavy particles in turbulent flows
Creators: name: Cencini, M.
name: Bec, J.
name: Biferale, L.
name: Boffetta, G.
name: Celani, A.
name: Lanotte, A. S.
name: Musacchio, S.
name: Toschi, F.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Chaotic Dynamics (nlin.CD)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: We present the results of Direct Numerical Simulations (DNS) of turbulent flows seeded with millions of passive inertial particles. The maximum Taylor's Reynolds number is around 200. We consider particles much heavier than the carrier flow in the limit when the Stokes drag force dominates their dynamical evolution. We discuss both the transient and the stationary regimes. In the transient regime, we study the growt of inhomogeneities in the particle spatial distribution driven by the preferential concentration out of intense vortex filaments. In the stationary regime, we study the acceleration fluctuations as a function of the Stokes number in the range [0.16:3.3]. We also compare our results with those of pure fluid tracers (St=0) and we find a critical behavior of inertia for small Stokes values. Starting from the pure monodisperse statistics we also characterize polydisperse suspensions with a given mean Stokes.
description: 13 pages, 10 figures, 2 tables
Output-Based Allocation of Environmental Policy Revenues and Imperfect Competition
Creators: name: Fischer, Carolyn
name: Fischer, Carolyn
Publisher: name: Unknown
Year: 2003
Subjects: subject: Resource /Energy Economics and Policy
subject: emission tax
subject: permit allocation
subject: earmarking
subject: tradable performance standards

description: Environmental policies with output-based refunding of the revenues effectively combine a tax on emissions with a subsidy to output. Three similar forms exist: tradable performance standards, an emissions tax with rebates, and tradable permits with output-based allocation. Two arguments for including an output subsidy are imperfect competition, in which an environmental regulation alone could exacerbate output underprovision, and imperfect participation, in which imposing a regulation on a subset of polluters could cause output to shift to exempt firms. However, both these scenarios imply that output shares among program participants are likely to be significant. In this situation, output-allocated permits offer less of a subsidy than a fixed rebate, and they can lead to inefficient shifting of production among participants. Rebating the emission tax reduces the incentive to abate, nor will marginal abatement costs be equalized if costs differ. These results hold in a Cournot duopoly model whether emission rates are determined simultaneously or strategically in a two-stage model.
Photon Wave Mechanics
Creators: name: Wang, Zhi-Yong
name: Xiong, Cai-Dong
name: Keller, Ole
Publisher: name: arXiv
Year: 2005
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: In contrast to wave functions in nonrelativistic quantum mechanics interpreted as probability amplitudes, wave functions in relativistic quantum mechanics have generalized meanings such as charge-density amplitudes, energy-density amplitudes as well as particle-number density amplitudes, etc. Applying electromagnetic field intensities we construct a photon wave function, it corresponds to the (1,0)+(0,1) spinor representation of the electromagnetic field, and can be interpreted as the energy-density amplitude of photons outside a source. In terms of photon wave functions we develop photon wave mechanics, which provides us with a new quantum-mechanical description for photons outside a source.
description: Revised version based on Chin. Phys. Lett. 24, 418 (2007)
Phosphine on Venus Cannot be Explained by Conventional Processes
Creators: name: Bains, William
name: Petkowski, Janusz J.
name: Seager, Sara
name: Ranjan, Sukrit
name: Sousa-Silva, Clara
name: Rimmer, Paul B.
name: Zhan, Zhuchang
name: Greaves, Jane S.
name: Richards, Anita M. S.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Chemical Physics (physics.chem-ph)
subject: Other Quantitative Biology (q-bio.OT)
subject: FOS: Physical sciences
subject: FOS: Biological sciences

description: The recent candidate detection of ~1 ppb of phosphine in the middle atmosphere of Venus is so unexpected that it requires an exhaustive search for explanations of its origin. Phosphorus-containing species have not been modelled for Venus' atmosphere before and our work represents the first attempt to model phosphorus species in the Venusian atmosphere. We thoroughly explore the potential pathways of formation of phosphine in a Venusian environment, including in the planet's atmosphere, cloud and haze layers, surface, and subsurface. We investigate gas reactions, geochemical reactions, photochemistry, and other non-equilibrium processes. None of these potential phosphine production pathways are sufficient to explain the presence of ppb phosphine levels on Venus. If PH3's presence in Venus' atmosphere is confirmed, it therefore is highly likely to be the result of a process not previously considered plausible for Venusian conditions. The process could be unknown geochemistry, photochemistry, or even aerial microbial life, given that on Earth phosphine is exclusively associated with anthropogenic and biological sources. The detection of phosphine adds to the complexity of chemical processes in the Venusian environment and motivates in situ follow up sampling missions to Venus. Our analysis provides a template for investigation of phosphine as a biosignature on other worlds.
description: v2 is in press in Astrobiology, Special Collection: Venus; v2 also expands on the potential of phosphides from the deep mantle volcanism as a source of PH3 (as suggested by Truong and Lunine 2021: https://www.pnas.org/content/118/29/e2021689118) and shows the volcanic source of PH3 to be unlikely
Wronskian formula for confluent second-order supersymmetric quantum mechanics
Creators: name: C., David J. Fernandez
name: Salinas-Hernandez, Encarnacion
Publisher: name: arXiv
Year: 2005
Subjects: subject: Quantum Physics (quant-ph)
subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: The confluent second-order supersymmetric quantum mechanics, for which the factorization energies tend to a single value, is studied. We show that the Wronskian formula remains valid if generalized eigenfunctions are taken as seed solutions. The confluent algorithm is used to generate SUSY partners of the Coulomb potential.
description: 7 pages, 1 figure, to be published in Physics Letters A
Time Domain Numerical Simulation for Transient Waves on Reconfigurable Coprocessor Platform
Creators: name: Lu, Mi
Publisher: name: figshare
Year: 2021
Subjects: subject: 10399 Numerical and Computational Mathematics not elsewhere classified
subject: FOS: Mathematics

description: A successful application-oriented reconfigurable coprocessor design requires not only a powerful FPGA based computing engine along with suitable hardware architecture, but also an efficient algorithm tailored for this special application. In this paper, we present our hardware architecture and numerical algorithms designed to speedup the time-domain finite-difference simulation of linear wave propagation problems in 2D and 3D space on FPGA-based reconfigurable platforms. Application fields of this work include seismic modeling and migration, computational electromagnetics, aeroacoustics, marine acoustics, to name a few. By writing first-order linear wave equations into second-order form, we halve the number of unknowns and simplify the treatment of parameters. We also adopt higher-order finite-difference (FD) schemes to further reduce the number of unknowns at the cost of increasing floating-point computations per discrete grid point. By doing so, we relief the bandwidth requirements between the FPGA and onboard memories but put more burden on the computing engine to take full advantage of FPGA’s computational potentials. The speed of our design implemented on a Xilinx ML401 Virtex-4 evaluation platform is about 1.5~4 times faster than a pure software implementation of the same algorithm running on a 3.0GHz DELL workstation. This impressive result is mainly attributed to the memory architecture design, which is well-tuned for our numerical higher-order FD algorithms and can utilize onboard memory bandwidth more wisely. Furthermore, the good scalability of our design makes it compatible with most commercial reconfigurable coprocessor platforms and correspondingly, the performance would be proportional to their onboard memory bandwidth.
Cleaning Up the Nuclear Weapons Complex: Exploring New Approaches
Creators: name: Probst, Katherine N.
name: Pilling, Carolyn A.
name: Dunn, Karen T.
name: Probst, Katherine N.
name: Pilling, Carolyn A.
name: Dunn, Karen T.
Publisher: name: Unknown
Year: 1996
Subjects: subject: Environmental Economics and Policy
subject: nuclear weapons complex
subject: integration
subject: environmental law
subject: environmental regulation

description: In recent years, policy experts have increasingly decried the "piecemeal" approach to environmental protection embodied in existing laws and regulations. This paper analyzes one aspect of the call for more integration: the feasibility and advisability of developing an integrated approach to regulating the cleanup of the nation's nuclear weapons complex. The Cold War has left an unprecedented set of difficulties at sites across the country where vast quantities of hazardous and radioactive materials must be properly managed. Regulatory fragmentation--particularly the phenomenon of multiple regulators and regulations driving the allocation of resources in an uncoordinated fashion--is nowhere more evident than in the current statutory and regulatory framework governing environmental management activities at this array of sites--the nuclear weapons complex. The objective of an integrated approach is to give regulators and the regulated community incentives to look holistically at environmental hazards, both existing and future, and to develop creative ways of setting priorities such that risk, cost effectiveness, and public concerns are taken into account. This paper describes recent efforts to achieve integration in the environmental arena, surveys the unique technical, regulatory, and political circumstances surrounding cleanup of the weapons complex, and offers some preliminary thoughts on how integration might be attained in this vital area. While administrative and regulatory changes could achieve some important steps in this direction, the authors conclude that legislative change is necessary for implementation of a truly integrated approach.
Superconformal symmetry in the interacting theory of (2,0) tensor multiplets and self-dual strings
Creators: name: Arvidsson, Par
Publisher: name: arXiv
Year: 2005
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We investigate the concept of superconformal symmetry in six dimensions, applied to the interacting theory of (2,0) tensor multiplets and self-dual strings. The action of a superconformal transformation on the superspace coordinates is found, both from a six-dimensional perspective and by using a superspace with eight bosonic and four fermionic dimensions. The transformation laws for all fields in the theory are derived, as well as general expressions for the transformation of on-shell superfields. Superconformal invariance is shown for the interaction of a self-dual string with a background consisting of on-shell tensor multiplet fields, and we also find an interesting relationship between the requirements of superconformal invariance and those of a local fermionic kappa-symmetry. Finally, we try to construct a superspace analogue of the Poincare dual to the string world-sheet and consider its properties under superconformal transformations.
description: 31 pages, LaTeX. v2: clarifications and minor corrections
Climate Change Policy
Creators: name: Shogren, Jason F.
name: Toman, Michael
name: Shogren, Jason F.
name: Toman, Michael
Publisher: name: Unknown
Year: 2000
Subjects: subject: Environmental Economics and Policy
subject: climate change
subject: incentive-based policy
subject: international environmental cooperation
subject: benefit-cost analysis

description: Having risen from relative obscurity as few as ten years ago, climate change now looms large among environmental policy issues. Its scope is global; the potential environmental and economic impacts are ubiquitous; the potential restrictions on human choices touch the most basic goals of people in all nations; and the sheer scope of the potential response - a significant shift away from using fossil fuels as the primary energy source in the modern economy -is daunting. In this paper, we explore the economics of climate change policy. We examine the risks that climate change poses for society, the benefits of protection against the effects of climate change, and the costs of alternative protection policies. We organize our discussion around three broad themes: why costs and benefits matter in assessing climate change policies, as does the uncertainty surrounding them; why well-designed, cost-effective climate policies are essential in addressing the threat of climate change; and why a coherent architecture of international agreements is key to successful policy implementation. We conclude the paper with a summary of key policy lessons and gaps in knowledge.
An Efficient Implementation of High-Accuracy Finite Difference Computing Engine on FPGAs
Creators: name: Lu, Mi
Publisher: name: figshare
Year: 2021
Subjects: subject: 10399 Numerical and Computational Mathematics not elsewhere classified
subject: FOS: Mathematics

description: Finite Difference (FD) methods are the most prevalent numerical modelling algorithms for evaluating initial or boundary value problems in scientific and engineering applications. Unfortunately, simulating time evolutions for transient physical phenomenon is computationally demanding and data-intensive. In this paper, we introduce an efficient implementation of FD computing engine on FPGA-based Reconfigurable Computing (RC) platform. Instead of following the formal high-order FD expressions with standard IEEE-754 compliant floating-point arithmetic units, we propose a new class of optimized finite-accurate FD schemes, whose FD coefficients are optimized to be represented with only a few binary bits without deteriorating numerical accuracy criterions. Furthermore, in order to simplify the implementation of floating-point summations, we replace the conventional costly floating-point adder tree by a floating-point/fixed-point hybrid accumulator using group-alignment technology. The resulting fully-pipelined FD computing engine with finite accurate coefficients can provide us similar or even better worst case relative and absolute rounding errors than standard floating-point arithmetic, but consumes only a fraction of hardware resources. This new design can be easily applied to our previous work [1] [4] and result in a more efficient and compact implementation with much higher computational performance.
SHAPing the Gas: Understanding Gas Shapes in Dark Matter Haloes with Interpretable Machine Learning
Creators: name: Valle, Luis Fernando Machado Poletti
name: Avestruz, Camille
name: Barnes, David J.
name: Farahi, Arya
name: Lau, Erwin T.
name: Nagai, Daisuke
Publisher: name: arXiv
Year: 2020
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: The non-spherical shapes of dark matter and gas distributions introduce systematic uncertainties that affect observable-mass relations and selection functions of galaxy groups and clusters. However, the triaxial gas distributions depend on the non-linear physical processes of halo formation histories and baryonic physics, which are challenging to model accurately. In this study we explore a machine learning approach for modelling the dependence of gas shapes on dark matter and baryonic properties. With data from the IllustrisTNG hydrodynamical cosmological simulations, we develop a machine learning pipeline that applies \pkg{XGBoost}, an implementation of gradient boosted decision trees, to predict radial profiles of gas shapes from halo properties. We show that \pkg{XGBoost} models can accurately predict gas shape profiles in dark matter haloes. We also explore model interpretability with \pkg{SHAP}, a method that identifies the most predictive properties at different halo radii. We find that baryonic properties best predict gas shapes in halo cores, whereas dark matter shapes are the main predictors in the halo outskirts. This work demonstrates the power of interpretable machine learning in modelling observable properties of dark matter haloes in the era of multi-wavelength cosmological surveys.
description: 14 pages, 8 figures, Accepted to MNRAS
Retroactive Liability and Future Risk: The Optimal Regulation of Underground Storage Tanks
Creators: name: Boyd, James
name: Kunreuther, Howard
name: Boyd, James
name: Kunreuther, Howard
Publisher: name: Unknown
Year: 1995
Subjects: subject: Risk and Uncertainty
subject: liability
subject: underground storage tanks

description: The optimal design of environmental liability policy focuses on two primary policy issues: the cleanup of existing sources of pollution and the definition and enforcement of policies to promote prospectively efficient environmental risk reduction. Through the analysis of a policy toward a pervasive environmental risk -- leaking underground storage tanks - we analyze the effectiveness of an existing policy governing retroactive and prospective liability issues and suggest ways in which that policy can be improved. While we find some theoretical support for the public financing of UST cleanups, we also find the current system to be flawed in its implementation. In general, the paper argues that public financing of past pollution cleanup costs can lead to greater future risk deterrence by allowing firms to more fully internalize the costs of future environmental risks. However, if it is practically or politically impossible to limit public financing to retroactive liabilities alone, the deterrent effect of such a system is vastly reduced.
Towards an affordable multi-DOF force feedback motion control input device
Creators: name: Yu, Zhang
Publisher: name: University of British Columbia
Year: 2009

description: A novel multi-degree-of-freedom force feedback motion control input device design has been proposed for 3D human-machine applications. This haptic device utilizes a new electro-mechanical design to achieve a large translation range for each axis of motion, while remaining suitable for mass production at low cost. Parallelogram linkages have been used to obtain displacements along each axis. The current device prototype uses an orthogonal arrangement of three parallelogram linkages to obtain displacements along all axes in Cartesian space. Springs have been used to center the device and a slot-and-tab hinge structure has been designed and used as a practical joint. An affordable and compact microelectronic sensor that is based on a grayscale with varying reflectance has been employed in order to sense the end-effector position. The nonlinearity of the sensor has been addressed and linearly compensated. A Lorentz force-based linear actuator design has been proposed. The actuator consists of a stator and a slider. The equivalent magnetic circuit model has been derived to assist the design computations. Experimental results show that the magnetic flux density along the air gap is approximately uniform and that the actuating force, although its level needs to be increased for use in the commercial product, is a linear function of the current applied to the coil windings on the slider. The device kinematics and dynamics have been derived and simulations have been performed to investigate the relationship between joint trajectories and work space actuating forces.
Electric activity at magnetic moment fragmentation in spin ice
Creators: name: Khomskii, D. I.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Spin ice systems display a variety of very nontrivial properties, the most striking being the existence in them of magnetic monopoles. Such monopole states can also have nontrivial electric properties: there exist electric dipoles attached to each monopole. A novel situation is encountered in the moment fragmentation (MF) state, in which monopoles and antimonopoles are perfectly ordered, whereas spins themselves remain disordered. We show that such partial ordering strongly modifies the electric activity of such systems: the electric dipoles, which are usually random and dynamic, become paired in the MF state in (d,-d) pairs, thus strongly reducing their electric activity. The electric currents existing in systems with noncoplanar spins are also strongly influenced by MF. We also consider modifications in dipole and current patterns in magnetic textures (domain walls, local defects) and at excitations with nontrivial dynamics in a MF state, which show very rich behaviour and which could in principle allow to control them by electric field.
Does the Value of a Statistical Life Vary with Age and Health Status? Evidence from the United States and Canada
Creators: name: Alberini, Anna
name: Cropper, Maureen L.
name: Krupnick, Alan J.
name: Simon, Nathalie B.
name: Alberini, Anna
name: Cropper, Maureen L.
name: Krupnick, Alan J.
name: Simon, Nathalie B.
Publisher: name: Unknown
Year: 2002
Subjects: subject: Health Economics and Policy
subject: willingness to pay
subject: mortality
subject: contingent valuation
subject: age
subject: health status

description: Much of the justification for environmental rulemaking rests on estimates of the benefits to society of reduced mortality rates. Yet the literature providing estimates of the willingness to pay (WTP) for mortality risk reductions measures the value that healthy, prime-aged adults place on reducing their risk of dying, whereas the majority of statistical lives saved by environmental programs, according to epidemiological studies, appear to be the lives of older people and people with chronically impaired health. This paper provides an empirical assessment of the effects of age and baseline health on WTP for mortality risk reductions by reporting the results of two contingent valuation surveys designed to test the above hypotheses. One survey was administered in-person to residents of Hamilton, Ontario, and the other to a nationally representative sample of U.S. residents using the Internet. Both surveys elicited respondents' WTP for reductions in mortality risk of different magnitudes. Respondents were limited to persons aged 40 years and older, including those older than 60, to examine the impact of age on WTP. Extensive information was collected about each respondent's health status to see whether it systematically influenced WTP. Our results provide weak support for the notion that WTP declines with age, but only after age 70. Specifically, in our Canadian sample, WTP declines by about 30% after age 70 compared with WTP at younger ages. There is no such statistically significant decline, however, in the U.S. sample. We similarly find no support for the idea that people who have cancer or chronic heart or lung disease are willing to pay less to reduce their risk of dying than people without these illnesses. If anything, people with these illnesses are willing to pay more.
Pseudo-Hermitian versus Hermitian position-dependent-mass Hamiltonians in a perturbative framework
Creators: name: Bagchi, B.
name: Quesne, C.
name: Roychoudhury, R.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We formulate a systematic algorithm for constructing a whole class of Hermitian position-dependent-mass Hamiltonians which, to lowest order of perturbation theory, allow a description in terms of PT-symmetric Hamiltonians. The method is applied to the Hermitian analogue of the PT-symmetric cubic anharmonic oscillator. A new example is provided by a Hamiltonian (approximately) equivalent to a PT-symmetric extension of the one-parameter trigonometric Poschl-Teller potential.
description: 13 pages, no figure, modified presentation, 6 additional references, published version
Interoperability and computational framework for simulating open channel hydraulics: application to sensitivity analysis and calibration of Gironde Estuary model
Creators: name: Goeury, Cedric
name: Audouin, Yoann
name: Zaoui, Fabrice
Publisher: name: arXiv
Year: 2020
Subjects: subject: Computational Engineering, Finance, and Science (cs.CE)
subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: Computation (stat.CO)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: Water resource management is of crucial societal and economic importance, requiring a strong capacity for anticipating environmental change. Progress in physical process knowledge, numerical methods and computational power, allows us to address hydro-environmental problems of growing complexity. Modeling of river and marine flows is no exception. With the increase in IT resources, environmental modeling is evolving to meet the challenges of complex real-world problems. This paper presents a new distributed Application Programming Interface (API) of the open source TELEMAC-MASCARET system to run hydro-environmental simulations with the help of the interoperability concept. Use of the API encourages and facilitates the combination of worldwide reference environmental libraries with the hydro-informatic system. Consequently, the objective of the paper is to promote the interoperability concept for studies dealing with such issues as uncertainty propagation, global sensitivity analysis, optimization, multi-physics or multi-dimensional coupling. To illustrate the capability of the API, an operational problem for improving the navigation capacity of the Gironde Estuary is presented. The API potential is demonstrated in a re-calibration context. The API is used for a multivariate sensitivity analysis to quickly reveal the most influential parameters which can then be optimally calibrated with the help of a data assimilation technique.
How Trade Politics Affect Invasive Species Control
Creators: name: Margolis, Michael
name: Shogren, Jason F.
name: Margolis, Michael
name: Shogren, Jason F.
Publisher: name: Unknown
Year: 2004
Subjects: subject: Environmental Economics and Policy
subject: invasive species
subject: protectionism
subject: tariff
subject: political economy

description: Trade has become the main mode of transport for many invasive species including diseases and agricultural pests. Most species are brought to their new homes unintentionally, which constitute a market failure rooted in international trade. Unless it is practical to drive invasion risk to zero, the external costs may justify a tariff. In this paper we analyze the political process likely to govern the formation of tariffs so justified, using a straightforward incorporation of an invasive species externality into Grossman and Helpman's well-known political economy model. We show our measure of disguised protectionism -the gap between the optimal tariff and that set in the equilibrium of the political economy game- is equal to the tariff that would be set if there were no invasive species and no international disciplines on trade policy. The informational needs required to distinguish disguised protectionism from legitimate public-goods protection are formidable.