IA Scholar Query: Distribution-Free Testing of Linear Functions on ℝⁿ.
https://scholar.archive.org/
Internet Archive Scholar query results feedeninfo@archive.orgSat, 22 Oct 2022 00:00:00 GMTfatcat-scholarhttps://scholar.archive.org/help1440The Greek Reflexes of *r̥ and *l̥
https://scholar.archive.org/work/u5mh6hitrjcyzp2ccei3kfyyh4
This is an open access chapter distributed under the terms of the cc by-nc 4.0 license. chapter 1 The Greek Reflexes of *r̥ and *l ̥ chapter 1 table 1 The mid-2nd millennium split into 4 dialect groups, according to Ruijgh South Greek *t(h)i > si Achaean *r̥ > -or-, -ro- Starting from these assumptions, Ruijgh concludes that the developments represented in Table 1 took place in the mid-second millennium, resulting in a split into four dialect groups.12 Note that the argument for a mid-second millennium split into four dialect groups depends also on morphological criteria, but the outcome of *r̥ is the only phonological criterion used in this connection. There are no other phonological developments that are demonstrably early and where the first millennium dialect groups have different reflexes.13 It does not come as a surprise, then, that alternatives to Ruijgh's scenario have been put forward. Risch (1955) maintained that there were no significant differences between 'Achaean' and Proto-Ionic in the Mycenaean period, and denies that the reflexes of *r̥ can be used as a reliable criterion.14 Heubeck (1972) argued that *r̥ was preserved in Mycenaean, and he was followed by García Ramón (1975), who claimed in addition that Proto-Aeolic retained *r̥ until a relatively late date. relativement récent en mycénien et, sans doute, aussi dans l'ensemble du grec") are much more cautious. 12 This is specifically Ruijgh 's view (e.g. 1985: 162-163, 1992: 84-87, 1996: 117). Similarly, Cowgill (1966: 94-95). 13 For a summary overview of morphological criteria (the athematic inf. act. in -ναι, -μεν, or -μεναι, or adverbs of the type ὅτε, ὅτα, ὅκα 'when') and lexical criteria (e.g. βούλομαι, βόλομαι vs. δήλομαι, βέλλομαι), see the classic study by Risch (1955), especially the table on p. 75, and also Cowgill (1966). The most important question is always whether a feature shared by two dialect groups can be proven to be a common innovation, or whether we may be dealing with shared archaisms or independent innovations. 14 This view is maintained also in Risch 1979a. However, Risch's views on the syllabic sonorants are idiosyncratic in at least two respects. First, he views the vocalization of syllabic liquids and nasals as part of the same development (which is implausible: see section 1.3.3). Secondly, he seems to have held that the o-vocalic outcome in Aeolic and Arcado-Cyprian is an archaism, i.e. that it can be viewed as a pre-stage of the a-colored reflex in Ionic-Attic, which is untenable (cf. the criticism in Cowgill 1966: 80 and 82).work_u5mh6hitrjcyzp2ccei3kfyyh4Sat, 22 Oct 2022 00:00:00 GMTLand use influences human mental and respiratory health in a conservation priority area in southeastern Brazil
https://scholar.archive.org/work/7h5rilprvjhhnjljnpwyjmhjum
Human activities generate negative environmental impacts that can compromise ecological processes and ecosystem services and thus, influence human health. We assessed how natural and altered areas affect human respiratory and mental health in one of the largest mining provinces in the world, the Quadrilatero Ferrifero (QF), in southeastern Brazil. We used a model selection approach to evaluate socioeconomic and environmental factors that would influence hospitalization rates for mental and behavioral disorders, as well as for respiratory diseases in 22 municipalities in QF. Municipalities with higher rates of urbanization had higher rates of hospitalizations for mental and behavioral disorders. Conversely, the adult population (15-59 years old) of both gender and the elderly female population (60 years old or more) presented lower rates of hospitalization for respiratory diseases in municipalities with a higher rate of urbanization, suggesting a greater ease of access to prophylactic measures of the population located in these municipalities compared to those with a lower rate of urbanization. Municipalities with larger urban forest areas had lower rates of hospitalization for respiratory diseases in the young (0-14 years) female population, while municipalities with larger mining areas had higher rates. The elderly male population (60 years or older) also had higher rates of hospitalization for respiratory diseases in municipalities with larger mining areas. Our findings show important ecosystem services provided by urban forests and highlight impacts on health, in different segments of the population, due to anthropogenic changes in the landscape.Matteus Carvalho Ferreira, Rodrigo Lima Massara, Marcelo Avila Chaves, Bruno Eduardo Fernandes Mota, Flavio Henrique Guimaraes Rodrigueswork_7h5rilprvjhhnjljnpwyjmhjumFri, 23 Sep 2022 00:00:00 GMTMuon-Electron Scattering at NNLO
https://scholar.archive.org/work/ynbcjxd5hvdozeih6hf4vogulm
This thesis provides a pedagogical overview of the theoretical foundations of the McMule framework, a Monte Carlo integrator for processes with muons and other leptons. Among other things, we show how the simple infrared structure in QED can be exploited to construct FKS^ℓ, a subtraction scheme for soft singularities to all orders in perturbation theory. Furthermore, we present the method of massification as a solution to the problem of multi-scale integrals in the presence of large scale hierarchies. Finally, we introduce next-to-soft stabilisation as an elegant tool to stabilise the numerically delicate real-virtual contribution. To this end, we generalise the Low-Burnett-Kroll theorem for massive fermions to one loop. This allows for a straightforward application of the method without the need of explicit calculations. We have developed all of these techniques with fully differential NNLO QED calculations in mind and have successfully applied them to many processes such as the muon decay as well as Bhabha and Møller scattering. One of the main drivers of these developments has been the MUonE experiment requiring a high-precision theory prediction for muon-electron (μ-e) scattering at the level of 10 ppm. The multi-scale nature of μ-e scattering makes this process particularly challenging from a technical point of view. Only the combined application of FKS^ℓ, massification, and next-to-soft stabilisation makes the corresponding calculation possible. This thesis therefore presents for the first time the fully differential calculation of the complete set of NNLO corrections to μ-e scattering. This represents a major step towards the ambitious 10 ppm target precision of the MUonE experiment.Tim Engelwork_ynbcjxd5hvdozeih6hf4vogulmThu, 22 Sep 2022 00:00:00 GMTSafety of Inhomogeneous Dose Distribution IMRT for High-Grade Glioma Reirradiation: A Prospective Phase I/II Trial (GLIORAD TRIAL)
https://scholar.archive.org/work/cdlceufsd5dhdld2auiaoiy6ae
Glioblastoma multiforme (GBM) is the most aggressive astrocytic primary brain tumor, and concurrent temozolomide (TMZ) and radiotherapy (RT) followed by maintenance of adjuvant TMZ is the current standard of care. Despite advances in imaging techniques and multi-modal treatment options, the median overall survival (OS) remains poor. As an alternative to surgery, re-irradiation (re-RT) can be a therapeutic option in recurrent GBM. Re-irradiation for brain tumors is increasingly used today, and several studies have demonstrated its feasibility. Besides differing techniques, the published data include a wide range of doses, emphasizing that no standard approach exists. The current study aimed to investigate the safety of moderate–high-voxel-based dose escalation in recurrent GBM. From 2016 to 2019, 12 patients met the inclusion criteria and were enrolled in this prospective single-center study. Retreatment consisted of re-irradiation with a total dose of 30 Gy (up to 50 Gy) over 5 days using the IMRT (arc VMAT) technique. A dose painting by numbers (DPBN)/dose escalation plan were performed, and a continuous relation between the voxel intensity of the functional image set and the risk of recurrence in that voxel were used to define target and dose distribution. Re-irradiation was well tolerated in all treated patients. No toxicities greater than G3 were recorded; only one patient had severe G3 acute toxicity, characterized by muscle weakness and fatigue. Median overall survival (OS2) and progression-free survival (PFS2) from the time of re-irradiation were 10.4 months and 5.7 months, respectively; 3-, 6-, and 12-month OS2 were 92%, 75%, and 42%, respectively; and 3-, 6-, and 12-month PFS2 were 83%, 42%, and 8%, respectively. Our work demonstrated a tolerable tolerance profile of this approach, and the future prospective phase II study will analyze the efficacy in terms of PFS and OS.Patrizia Ciammella, Salvatore Cozzi, Andrea Botti, Lucia Giaccherini, Roberto Sghedoni, Matteo Orlandi, Manuela Napoli, Rosario Pascarella, Anna Pisanello, Marco Russo, Francesco Cavallieri, Maria Paola Ruggieri, Silvio Cavuto, Luisa Savoldi, Cinzia Iotti, Mauro Ioriwork_cdlceufsd5dhdld2auiaoiy6aeThu, 22 Sep 2022 00:00:00 GMTRelationship between Pain, Fear of Falling and Physical Performance in Older People Residents in Long-Stay Institutions: A Cross-Sectional Study
https://scholar.archive.org/work/miact3ckwvbqxoozbgy4ekm2fy
To analyze the relationship between pain, the fear of falling and functional performance in older people living in a long-stay institution (LSI) in the interior of northeastern Brazil. Methods: A cross-sectional study was conducted with 133 older residents in an LSI in the State of Paraíba. The instruments used for data collection were the Geriatric Pain Measure (GPM), the Falls Efficacy Scale-International (FES-I) and the Short Physical Performance Battery (SPPB). Results: Pain was reported by 57.5% of those evaluated, 48% being classified as chronic pain and presenting an average of 25.2 in the GPM. As for physical performance, assessed using the SPPB, the 133 older residents showed moderate to poor performance, with an average of 6.43 (±2.96) on the scale. By correlating the adjusted GPM values with the FES-I, a weak and statistically significant positive correlation was obtained (ρ = 0.31: p < 0.001). Conclusions: It can be concluded that those who reported pain had a worse performance in the applied tests, in addition to having higher scores on the scale referring to a fear of falling.Sabrina Fernandes, Weslley Sales, Diego Tavares, Dayanna Pereira, Patrícia Nóbrega, Cristina Holanda, Alvaro Macielwork_miact3ckwvbqxoozbgy4ekm2fyThu, 22 Sep 2022 00:00:00 GMTImaginary-time open-chain path-integral approach for two-state time correlation functions and applications in charge transfer
https://scholar.archive.org/work/ohjkpwku2nh3jl2pizp3vt3hj4
Quantum time correlation functions (TCFs) involving two states are important for describing nonadiabatic dynamical processes such as charge transfer (CT). Based on a previous single-state method, we propose an imaginary-time open-chain path-integral (OCPI) approach for evaluating the two-state symmetrized TCFs. Expressing the forward and backward propagation on different electronic potential energy surfaces as a complex-time path integral, we then transform the path variables to average and difference variables such that the integration over the difference variables up to the second order can be performed analytically. The resulting expression for the symmetrized TCF is equivalent to sampling the open-chain configurations in an effective potential that corresponds to the average surface. Using importance sampling over the extended OCPI space via open path-integral molecular dynamics, we tested the resulting path-integral approximation by calculating the Fermi's golden rule CT rate constant within a widely used spin-boson model. Comparing with the real-time linearized semiclassical method and analytical result, we show that the imaginary-time OCPI provides an accurate two-state symmetrized TCF and rate constant in the typical turnover region. It is shown that the first bead of the open chain corresponds to physical zero-time and that the endpoint bead corresponds to final time t; oscillations of the end-to-end distance perfectly match the nuclear mode frequency. The two-state OCPI scheme is seen to capture the tested model's electronic quantum coherence and nuclear quantum effects accurately.Zengkui Liu, Wen Xu, Mark E. Tuckerman, Xiang Sunwork_ohjkpwku2nh3jl2pizp3vt3hj4Wed, 21 Sep 2022 00:00:00 GMTRadon concentration variations at the Yangyang underground laboratory
https://scholar.archive.org/work/z36x372eu5b4jjxu36exr25r34
The concentration of radon in the air has been measured in the 700 m-deep Yangyang underground laboratory between October 2004 and May 2022. The average concentrations in two experimental areas, called A6 and A5, were measured to be 53.4±0.2 Bq/m3 and 33.5±0.1 Bq/m3, respectively. The lower value in the A5 area reflects the presence of better temperature control and ventilation. The radon concentrations sampled within the two A5 experimental rooms' air are found to be correlated to the local surface temperature outside of the rooms, with correlation coefficients r = 0.22 and r = 0.70. Therefore, the radon concentrations display a seasonal variation, because the local temperature driven by the overground season influences air ventilation in the experimental areas. A fit on the annual residual concentrations finds that the amplitude occurs each year on August, 31±6 days.C. Ha, Y. Jeong, W. G. Kang, J. Kim, K. W. Kim, S. K. Kim, Y. D. Kim, H. S. Lee, M. H. Lee, M. J. Lee, Y. J. Lee, K. M. Seowork_z36x372eu5b4jjxu36exr25r34Wed, 21 Sep 2022 00:00:00 GMTHopf algebras and non-associative algebras in the study of iterated-integral signatures and rough paths
https://scholar.archive.org/work/vri56bn4anbznfnl6s7cmyo5fq
Over the course of three different collaborative projects, we gather evidence of how Hopf, Lie and pre-Lie, Zinbiel and dendriform, as well as Tortkara algebras appear in and influence the systematic combinatorial treatment of iterated-integral signatures of paths and rough paths. First, we investigate how Lie and pre-Lie structures of Lie polynomials and trees give rise to Hopf algebra homomorphisms which one can use to translate the higher orders of rough paths, and thus in a sense renormalize them. We obtain an interplay at the level of the rough differential equations (RDEs) driven by the translated rough path vs the original rough path, and furthermore explore how this translation-renormalization is in bijection with a renormalization group of a corresponding regularity structure. Secondly, we answer a question by Bernd Sturmfels of how the signature of a path under a polynomial map p(X) can be retrieved from the signature of the original path X. After we discussed this with elementary means, we explain how this can be seen as a corollary of a much more general statement on homomorphisms on the halfshuffle Zinbiel algebra vs the iterated-integral signature, which can be seen as being immediately equivalent to the classic halfshuffle relation of the signature. Finally, we study how the signed area enclosed by a two-dimensional path and the connection line between starting point and end point corresponds to an algebraic anticommutative area operation satisfying the Tortkara identity. We revisit the work of Rocha on coordinates of the first kind which led him to introduce such an area operation for the first time, work which can be formulated in terms of a dendriform algebra and the pre-Lie, symmetrized pre-Lie, Lie and associative operations it canonically induces. With our main result in this project being the fact that the whole shuffle algebra can be expressed in terms of shuffle polynomials of area polynomials, which answers a conjecture by Lyons that the knowledge of all areas of areas suffices to compute [...]Rosa Lili Dora Preiß, Technische Universität Berlin, Peter K. Frizwork_vri56bn4anbznfnl6s7cmyo5fqWed, 21 Sep 2022 00:00:00 GMTThe first minutes of a binary-driven hypernova
https://scholar.archive.org/work/bhy7frgmyja2xdqiq6pbode6wi
We simulate the first minutes of the evolution of a binary-driven hypernova (BdHN) event, with a special focus on the associated accretion processes of supernova (SN) ejecta onto the newborn neutron star (νNS) and the NS companion. We calculate the rotational evolution of the νNS and the NS under the torques exerted by the accreted matter and the magnetic field. We take into account general relativistic effects and use realistic hypercritical accretion rates obtained from three-dimensional smoothed-particle-hydrodynamics (SPH) numerical simulations of the BdHN for a variety of orbital periods. We show that the rotation power of the νNS has a unique double-peak structure while that of the NS has a single peak. These peaks are of comparable intensity and can occur very close in time or even simultaneously depending on the orbital period and the initial angular momentum of the stars. We outline the consequences of the above features in the early emission and their consequent observation in long gamma-ray bursts (GRBs).L. M. Becerra, R. Moradi, J. A. Rueda, R. Ruffini, Y. Wangwork_bhy7frgmyja2xdqiq6pbode6wiWed, 21 Sep 2022 00:00:00 GMTIntermittent fasting promotes axonal regeneration through the gut microbiome derived metabolite: Indole-3-Propionic acid
https://scholar.archive.org/work/hxzp54iskbej3norlhodek36ce
Spontaneous functional mammalian axonal regeneration following injury fails. High density and fast axon regeneration across distances are needed for efficient repair in humans. These are likely influenced by complex neuronal intrinsic and extrinsic metabolic and signalling mechanisms. Environmental factors such as exercise and diet have been shown to affect metabolism and signalling promoting health and repair processes in several diseases. Intermittent fasting (IF) has been shown to increase synaptic plasticity and neurogenesis that partially share molecular mechanisms with axonal regeneration. Recent publications showed that IF was followed by enhanced functional recovery following spinal cord injury. We hypothesized that IF would promote axonal regeneration after injury by a combinatorial effect of systemic and cell intrinsic mechanisms influencing neuronal metabolism and regenerative signalling pathways. Hence, we studied axonal regeneration after sciatic nerve injury in fasting (IF) versus non-fasting animals to discover that IF significantly promotes axonal regeneration. We next found IF-dependent upregulation of gut bacteria-derived indole metabolites and identified indole-3-propionic acid (IPA) as a key factor in IF dependent axonal regeneration. IPA treatment in ad libitum-fed mice increased axonal regeneration after injury. Further, RNA sequencing transcriptomic analysis from dorsal root ganglia neurons suggests that neutrophils and interferon gamma play an important role in IPA-dependent axonal regeneration. These studies offer both a novel mechanism and they have the potential to provide a novel translational approach for nerve repair and functional recovery after injury.Elisabeth Serger, Simone Di Giovanni, David Carlingwork_hxzp54iskbej3norlhodek36ceWed, 21 Sep 2022 00:00:00 GMTAn Augmented Likelihood Approach for the Discrete Proportional Hazards Model Using Auxiliary and Validated Outcome Data – with Application to the HCHS/SOL Study
https://scholar.archive.org/work/zg3k2f6agbc7jh7vigrsf36shi
In large epidemiologic studies, it is typical for an inexpensive, non-invasive procedure to be used to record disease status during regular follow-up visits, with less frequent assessment by a gold standard test. Inexpensive outcome measures like self-reported disease status are practical to obtain, but can be error-prone. Association analysis reliant on error-prone outcomes may lead to biased results; however, restricting analyses to only data from the less frequently observed error-free outcome could be inefficient. We have developed an augmented likelihood that incorporates data from both error-prone outcomes and a gold standard assessment. We conduct a numerical study to show how we can improve statistical efficiency by using the proposed method over standard approaches for interval-censored survival data that do not leverage auxiliary data. We extend this method for the complex survey design setting so that it can be applied in our motivating data example. Our method is applied to data from the Hispanic Community Health Study/Study of Latinos to assess the association between energy and protein intake and the risk of incident diabetes. In our application, we demonstrate how our method can be used in combination with regression calibration to additionally address the covariate measurement error in self-reported diet.Lillian A. Boe, Pamela A. Shawwork_zg3k2f6agbc7jh7vigrsf36shiWed, 21 Sep 2022 00:00:00 GMTConformal removability of SLE_4
https://scholar.archive.org/work/lsu5z5mw7rakpmq2kf6qa62srq
We consider the Schramm-Loewner evolution (SLE_κ) with κ=4, the critical value of κ > 0 at or below which SLE_κ is a simple curve and above which it is self-intersecting. We show that the range of an SLE_4 curve is a.s. conformally removable, answering a question posed by Sheffield. Such curves arise as the conformal welding of a pair of independent critical (γ=2) Liouville quantum gravity (LQG) surfaces along their boundaries and our result implies that this conformal welding is unique. In order to establish this result, we give a new sufficient condition for a set X ⊆𝐂 to be conformally removable which applies in the case that X is not necessarily the boundary of a simply connected domain.Konstantinos Kavvadias, Jason Miller, Lukas Schougwork_lsu5z5mw7rakpmq2kf6qa62srqWed, 21 Sep 2022 00:00:00 GMTIntegrated analysis of multimodal single-cell data with structural similarity
https://scholar.archive.org/work/tlckituchjbmlju6ounqre6oqi
Multimodal single-cell sequencing technologies provide unprecedented information on cellular heterogeneity from multiple layers of genomic readouts. However, joint analysis of two modalities without properly handling the noise often leads to overfitting of one modality by the other and worse clustering results than vanilla single-modality analysis. How to efficiently utilize the extra information from single cell multi-omics to delineate cell states and identify meaningful signal remains as a significant computational challenge. In this work, we propose a deep learning framework, named SAILERX, for efficient, robust, and flexible analysis of multi-modal single-cell data. SAILERX consists of a variational autoencoder with invariant representation learning to correct technical noises from sequencing process, and a multimodal data alignment mechanism to integrate information from different modalities. Instead of performing hard alignment by projecting both modalities to a shared latent space, SAILERX encourages the local structures of two modalities measured by pairwise similarities to be similar. This strategy is more robust against overfitting of noises, which facilitates various downstream analysis such as clustering, imputation, and marker gene detection. Furthermore, the invariant representation learning part enables SAILERX to perform integrative analysis on both multi- and single-modal datasets, making it an applicable and scalable tool for more general scenarios.Yingxin Cao, Laiyi Fu, Jie Wu, Qinke Peng, Qing Nie, Jing Zhang, Xiaohui Xiework_tlckituchjbmlju6ounqre6oqiWed, 21 Sep 2022 00:00:00 GMTExact two-component Hamiltonians for relativistic quantum chemistry: Two-electron picture-change corrections made simple
https://scholar.archive.org/work/wg5o56npwbdnpmxwdn4hbhpx4m
Based on self-consistent field (SCF) atomic mean-field (amf) quantities, we present two simple yet computationally efficient and numerically accurate matrix-algebraic approaches to correct both scalar-relativistic and spin-orbit two-electron picture-change effects (PCEs) arising within an exact two-component (X2C) Hamiltonian framework. Both approaches, dubbed amfX2C and e(xtended)amfX2C, allow us to uniquely tailor PCE corrections to mean-field models, viz. Hartree-Fock or Kohn-Sham DFT, in the latter case also avoiding the need for a point-wise calculation of exchange-correlation PCE corrections. We assess the numerical performance of these PCE correction models on spinor energies of group 18 (closed-shell) and group 16 (open-shell) diatomic molecules, achieving a consistent ≈10-5 Hartree accuracy compared to reference four-component data. Additional tests include SCF calculations of molecular properties such as absolute contact density and contact density shifts in copernicium fluoride compounds (CnFn, n = 2,4,6), as well as equation-of-motion coupled-cluster calculations of x-ray core-ionization energies of 5d- and 6d-containing molecules, where we observe an excellent agreement with reference data. To conclude, we are confident that our (e)amfX2C PCE correction models constitute a fundamental milestone toward a universal and reliable relativistic two-component quantum-chemical approach, maintaining the accuracy of the parent four-component one at a fraction of its computational cost.Stefan Knecht, Michal Repisky, Hans Jørgen Aagaard Jensen, Trond Sauework_wg5o56npwbdnpmxwdn4hbhpx4mWed, 21 Sep 2022 00:00:00 GMTFDP control in multivariate linear models using the bootstrap
https://scholar.archive.org/work/hql7d6tptfau3ekncxglkzqsoe
In this article we develop a method for performing post hoc inference of the False Discovery Proportion (FDP) over multiple contrasts of interest in the multivariate linear model. To do so we use the bootstrap to simulate from the distribution of the null contrasts. We combine the bootstrap with the post hoc inference bounds of Blanchard (2020) and prove that doing so provides simultaneous asymptotic control of the FDP over all subsets of hypotheses. This requires us to demonstrate consistency of the multivariate bootstrap in the linear model, which we do via the Lindeberg Central Limit Theorem, providing a simpler proof of this result than that of Eck (2018). We demonstrate, via simulations, that our approach provides simultaneous control of the FDP over all subsets and is typically more powerful than existing, state of the art, parametric methods. We illustrate our approach on functional Magnetic Resonance Imaging data from the Human Connectome project and on a transcriptomic dataset of chronic obstructive pulmonary disease.Samuel Davenport, Bertrand Thirion, Pierre Neuvialwork_hql7d6tptfau3ekncxglkzqsoeTue, 20 Sep 2022 00:00:00 GMTRobustCalibration: Robust Calibration of Computer Models in R
https://scholar.archive.org/work/pzzdir6bovaghp4nxmt4cd2oee
Two fundamental research tasks in science and engineering are forward predictions and data inversion. This article introduces a recent R package RobustCalibration for Bayesian data inversion and model calibration by experiments and field observations. Mathematical models for forward predictions are often written in computer code, and they can be computationally expensive slow to run. To overcome the computational bottleneck from the simulator, we implemented a statistical emulator from the RobustGaSP package for emulating both scalar-valued or vector-valued computer model outputs. Both posterior sampling and maximum likelihood approach are implemented in the RobustCalibration package for parameter estimation. For imperfect computer models, we implement Gaussian stochastic process and the scaled Gaussian stochastic process for modeling the discrepancy function between the reality and mathematical model. This package is applicable to various types of field observations, such as repeated experiments and multiple sources of measurements. We discuss numerical examples of calibrating mathematical models that have closed-form expressions, and differential equations solved by numerical methods.Mengyang Guwork_pzzdir6bovaghp4nxmt4cd2oeeTue, 20 Sep 2022 00:00:00 GMTSoK: Decentralized Finance (DeFi) Attacks
https://scholar.archive.org/work/icxbhqbognay5mo4c4spl5n2ai
Within just four years, the blockchain-based Decentralized Finance (DeFi) ecosystem has accumulated a peak total value locked (TVL) of more than 253 billion USD. This surge in DeFi's popularity has, unfortunately, been accompanied by many impactful incidents. According to our data, users, liquidity providers, speculators, and protocol operators suffered a total loss of at least 3.24 USD from Apr 30, 2018 to Apr 30, 2022. Given the blockchain's transparency and increasing incident frequency, two questions arise: How can we systematically measure, evaluate, and compare DeFi incidents? How can we learn from past attacks to strengthen DeFi security? In this paper, we introduce a common reference frame to systematically evaluate and compare DeFi incidents, including both attacks and accidents. We investigate 77 academic papers, 30 audit reports, and 181 real-world incidents. Our open data reveals several gaps between academia and the practitioners' community. For example, few academic papers address "price oracle attacks" and "permissonless interactions", while our data suggests that they are the two most frequent incident types (15% and 10.5% correspondingly). We also investigate potential defenses, and find that: (i) 103 (56%) of the attacks are not executed atomically, granting a rescue time frame for defenders; (ii) SoTA bytecode similarity analysis can at least detect 31 vulnerable/23 adversarial contracts; and (iii) 33 (15.3%) of the adversaries leak potentially identifiable information by interacting with centralized exchanges.Liyi Zhou, Xihan Xiong, Jens Ernstberger, Stefanos Chaliasos, Zhipeng Wang, Ye Wang, Kaihua Qin, Roger Wattenhofer, Dawn Song, Arthur Gervaiswork_icxbhqbognay5mo4c4spl5n2aiTue, 20 Sep 2022 00:00:00 GMTMotion Planning Under Uncertainty with Complex Agents and Environments via Hybrid Search
https://scholar.archive.org/work/t3x4qanyezeirfutoiqslvs6h4
As autonomous systems and robots are applied to more real world situations, they must reason about uncertainty when planning actions. Mission success oftentimes cannot be guaranteed and the planner must reason about the probability of failure. Unfortunately, computing a trajectory that satisfies mission goals while constraining the probability of failure is difficult because of the need to reason about complex, multidimensional probability distributions. Recent methods have seen success using chance-constrained, model-based planning. However, the majority of these methods can only handle simple environment and agent models. We argue that there are two main drawbacks of current approaches to goal-directed motion planning under uncertainty. First, current methods suffer from an inability to deal with expressive environment models such as 3D non-convex obstacles. Second, most planners rely on considerable simplifications when computing trajectory risk including approximating the agent's dynamics, geometry, and uncertainty. In this article, we apply hybrid search to the risk-bound, goal-directed planning problem. The hybrid search consists of a region planner and a trajectory planner. The region planner makes discrete choices by reasoning about geometric regions that the autonomous agent should visit in order to accomplish its mission. In formulating the region planner, we propose landmark regions that help produce obstacle-free paths. The region planner passes paths through the environment to a trajectory planner; the task of the trajectory planner is to optimize trajectories that respect the agent's dynamics and the user's desired risk of mission failure. We discuss three approaches to modeling trajectory risk: a CDF-based approach, a sampling-based collocation method, and an algorithm named Shooting Method Monte Carlo. These models allow computation of trajectory risk with more complex environments, agent dynamics, geometries, and models of uncertainty than past approaches. A variety of 2D and 3D test cases are presented including a linear case, a Dubins car model, and an underwater autonomous vehicle. The method is shown to outperform other methods in terms of speed and utility of the solution. Additionally, the models of trajectory risk are shown to better approximate risk in simulation.Daniel Strawser, Brian Williamswork_t3x4qanyezeirfutoiqslvs6h4Mon, 19 Sep 2022 00:00:00 GMTCosmic Ray Interstellar Propagation Tool using Itô Calculus (criptic): software for simultaneous calculation of cosmic ray transport and observational signatures
https://scholar.archive.org/work/4zwtkafiwngzldbftm6u5gwc7e
We present criptic, the Cosmic Ray Interstellar Propagation Tool using Itô Calculus, a new open-source software package to simulate the propagation of cosmic rays through the interstellar medium and to calculate the resulting observable non-thermal emission. Criptic solves the Fokker-Planck equation describing transport of cosmic rays on scales larger than that on which their pitch angles become approximately isotropic, and couples this to a rich and accurate treatment of the microphysical processes by which cosmic rays in the energy range ∼MeV to ∼PeV lose energy and produce emission. Criptic is deliberately agnostic as to both the cosmic ray transport model and the state of the background plasma through which cosmic rays travel. It can solve problems where cosmic rays stream, diffuse, or perform arbitrary combinations of both, and the coefficients describing these transport processes can be arbitrary functions of the background plasma state, the properties of the cosmic rays themselves, and local integrals of the cosmic ray field itself (e.g., the local cosmic ray pressure or pressure gradient). The code is parallelised using a hybrid OpenMP-MPI paradigm, allowing rapid calculations exploiting multiple cores and nodes on modern supercomputers. Here we describe the numerical methods used in the code, our treatment of the microphysical processes, and the set of code tests and validations we have performed.Mark R. Krumholz, Roland M. Crocker, Matt L. Sampsonwork_4zwtkafiwngzldbftm6u5gwc7eMon, 19 Sep 2022 00:00:00 GMTImplementation of an efficient Bayesian search for gravitational wave bursts with memory in pulsar timing array data
https://scholar.archive.org/work/xzyfp6tetnag7buqowcsomdueq
The standard Bayesian technique for searching pulsar timing data for gravitational wave (GW) bursts with memory (BWMs) using Markov Chain Monte Carlo (MCMC) sampling is very computationally expensive to perform. In this paper, we explain the implementation of an efficient Bayesian technique for searching for BWMs. This technique makes use of the fact that the signal model for Earth-term BWMs (BWMs passing over the Earth) is fully factorizable. We estimate that this implementation reduces the computational complexity by a factor of 100. We also demonstrate that this technique gives upper limits consistent with published results using the standard Bayesian technique, and may be used to perform all of the same analyses that standard MCMC techniques can perform.Jerry Sun, Paul T. Baker, Aaron D. Johnson, Dustin R. Madison, Xavier Siemenswork_xzyfp6tetnag7buqowcsomdueqMon, 19 Sep 2022 00:00:00 GMT