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    123448 research outputs found

    On HTLC-Based Protocols for Multi-Party Cross-Chain Swaps

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    In his 2018 paper, Herlihy introduced an atomic protocol for multi-party asset swaps across different blockchains. His model represents an asset swap by a directed graph whose nodes are the participating parties and edges represent asset transfers, and rational behavior of the participants is captured by a preference relation between a protocol's outcomes. Asset transfers between parties are achieved using smart contracts. These smart contracts are quite involved and they require storage and processing of a large number of paths in the swap digraph, limiting practical significance of his protocol. His paper also describes a different protocol that uses only standard hash time-lock contracts (HTLC's), but this simpler protocol applies only to some special types of digraphs. He left open the question whether there is a simple and efficient protocol for cross-chain asset swaps in arbitrary digraphs. Motivated by this open problem, we conducted a comprehensive study of \emph{HTLC-based protocols}, in which all asset transfers are implemented with HTLCs. Our main contribution is a full characterization of swap digraphs that have such protocols

    Observability of substructures in planet-forming disk in (sub)cm wavelength with SKA and ngVLA

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    Current imaging observations of protoplanetary disks using ALMA primarily focus on the sub-millimeter wavelength, leaving a gap in effective observational approaches for centimeter-sized dust, which is crucial to the issue of planet formation. The forthcoming SKA and ngVLA may rectify this deficiency. In this paper, we employ multi-fluid hydrodynamic numerical simulations and radiative transfer calculations to investigate the potential of SKA1-Mid, ngVLA, and SKA2 for imaging protoplanetary disks at sub-cm/cm wavelengths. We create mock images with ALMA/SKA/ngVLA at multi-wavelengths based on the hydrodynamical simulation output, and test different sensitivity and spatial resolutions. We discover that both SKA and ngVLA will serve as excellent supplements to the existing observational range of ALMA, and their high resolution enables them to image substructures in the disk's inner region (\sim 5 au from the stellar). Our results indicate that SKA and ngVLA can be utilized for more extended monitoring programs in the centimeter waveband. While in the sub-centimeter range, ngVLA possesses the capability to produce high-fidelity images within shorter observation times (\sim 1 hour on source time) than previous research, holding potential for future survey observations. We also discuss for the first time the potential of SKA2 for observing protoplanetary disks at a 0.7 cm wavelength.Comment: 10 pages, 6 figures, accepted by ApJ. Welcome any comments and suggestions

    RACE-SM: Reinforcement Learning Based Autonomous Control for Social On-Ramp Merging

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    Autonomous parallel-style on-ramp merging in human controlled traffic continues to be an existing issue for autonomous vehicle control. Existing non-learning based solutions for vehicle control rely on rules and optimization primarily. These methods have been seen to present significant challenges. Recent advancements in Deep Reinforcement Learning have shown promise and have received significant academic interest however the available learning based approaches show inadequate attention to other highway vehicles and often rely on inaccurate road traffic assumptions. In addition, the parallel-style case is rarely considered. A novel learning based model for acceleration and lane change decision making that explicitly considers the utility to both the ego vehicle and its surrounding vehicles which may be cooperative or uncooperative to produce behaviour that is socially acceptable is proposed. The novel reward function makes use of Social Value Orientation to weight the vehicle's level of social cooperation and is divided into ego vehicle and surrounding vehicle utility which are weighted according to the model's designated Social Value Orientation. A two-lane highway with an on-ramp divided into a taper-style and parallel-style section is considered. Simulation results indicated the importance of considering surrounding vehicles in reward function design and show that the proposed model matches or surpasses those in literature in terms of collisions while also introducing socially courteous behaviour avoiding near misses and anti-social behaviour through direct consideration of the effect of merging on surrounding vehicles.Comment: Updated explanation of TTC, page

    On additive differential probabilities of the composition of bitwise exclusive-or and a bit rotation

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    Properties of the additive differential probability adpXR\mathrm{adp}^{\mathrm{XR}} of the composition of bitwise XOR and a bit rotation are investigated, where the differences are expressed using addition modulo 2n2^n. This composition is widely used in ARX constructions consisting of additions modulo 2n2^n, bit rotations and bitwise XORs. Differential cryptanalysis of such primitives may involve maximums of adpXR\mathrm{adp}^{\mathrm{XR}}, where some of its input or output differences are fixed. Although there is an efficient way to calculate this probability (Velichkov et al, 2011), many of its properties are still unknown. In this work, we find maximums of adpXR\mathrm{adp}^{\mathrm{XR}}, where the rotation is one bit left/right and one of its input differences is fixed. Some symmetries of adpXR\mathrm{adp}^{\mathrm{XR}} are obtained as well. We provide all its impossible differentials in terms of regular expression patterns and estimate the number of them. This number turns out to be maximal for the one bit left rotation and noticeably less than the number of impossible differentials of bitwise XOR

    A Knowledge-Injected Curriculum Pretraining Framework for Question Answering

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    Knowledge-based question answering (KBQA) is a key task in NLP research, and also an approach to access the web data and knowledge, which requires exploiting knowledge graphs (KGs) for reasoning. In the literature, one promising solution for KBQA is to incorporate the pretrained language model (LM) with KGs by generating KG-centered pretraining corpus, which has shown its superiority. However, these methods often depend on specific techniques and resources to work, which may not always be available and restrict its application. Moreover, existing methods focus more on improving language understanding with KGs, while neglect the more important human-like complex reasoning. To this end, in this paper, we propose a general Knowledge-Injected Curriculum Pretraining framework (KICP) to achieve comprehensive KG learning and exploitation for KBQA tasks, which is composed of knowledge injection (KI), knowledge adaptation (KA) and curriculum reasoning (CR). Specifically, the KI module first injects knowledge into the LM by generating KG-centered pretraining corpus, and generalizes the process into three key steps that could work with different implementations for flexible application. Next, the KA module learns knowledge from the generated corpus with LM equipped with an adapter as well as keeps its original natural language understanding ability to reduce the negative impacts of the difference between the generated and natural corpus. Last, to enable the LM with complex reasoning, the CR module follows human reasoning patterns to construct three corpora with increasing difficulties of reasoning, and further trains the LM from easy to hard in a curriculum manner. We provide an implementation of the general framework, and evaluate the proposed KICP on four real-word datasets. The results demonstrate that our framework can achieve higher performances.Comment: Accepted by WWW 202

    Should the choice of BOIN design parameter p.tox only depend on the target DLT rate?

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    When the early stopping parameter n.earlystop is relatively small or the cohortsize value is not optimized via simulation, it may be better to use p.tox < 1.4 * target.DLT.rate, or try out different cohort sizes, or increase n.earlystop, whichever is both feasible and provides better operating characteristics. This is because if the cohortsize was not optimized via simulation, even when n.earlystop = 12, the BOIN escalation/de-escalation rules generated using p.tox = 1.4 * target.DLT.rate could be exactly the same as those calculated using p.tox > 3 * target.DLT.rate, which might not be acceptable for some pediatric trials targeting 10% DLT rate. The traditional 3+3 design stops the dose finding process when 3 patients have been treated at the current dose level, 0 DLT has been observed, and the next higher dose has already been eliminated. If additional 3 patients were required to be treated at the current dose in the situation described above, the corresponding boundary table could be generated using BOIN design with target DLT rates ranging from 18% to 29%, p.saf ranging from 8% to 26%, and p.tox ranging from 39% to 99%. To generate the boundary table of this 3+3 design variant, BOIN parameters also need to satisfy a set of conditions

    The Carbon Isotopic Ratio and Planet Formation

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    We present the first detection of 13CCH in a protoplanetary disk (TW Hya). Using observations of C2H we measure CCH/13CCH = 65 +/- 20 in gas with a CO isotopic ratio of 12CO/13CO = 21 +/- 5 (Yoshida et al. 2022a). The TW Hya disk exhibits a gas phase C/O that exceeds unity and C2H is the tracer of this excess carbon. We confirm that the TW Hya gaseous disk exhibits two separate carbon isotopic reservoirs as noted previously (Yoshida et al. 2022a). We explore two theoretical solutions for the development of this dichotomy. One model represents TW Hya today with a protoplanetary disk exposed to a cosmic ray ionization rate that is below interstellar as consistent with current estimates. We find that this model does not have sufficient ionization in cold (T < 40 K) layers to activate carbon isotopic fractionation. The second model investigates a younger TW Hya protostellar disk exposed to an interstellar cosmic ray ionization rate. We find that the younger model has sources of ionization deeper in a colder disk that generates two independent isotopic reservoirs. One reservoir is 12C-enriched carried by methane/hydrocarbon ices and the other is 13C-enriched carried by gaseous CO. The former potentially provides a source of methane/hydrocarbon ices to power the chemistry that generates the anomalously strong C2_2H emission in this (and other) disk systems in later stages. The latter provides a source of gaseous 13C-rich material to generate isotopic enrichments in forming giant planets as recently detected in the super-Jupiter TYC 8998-760-1 b by Zhang et al. (2021).Comment: 16 pages, 8 figures, accepted by the Astrophysical Journa

    Meta-Cognitive Analysis: Evaluating Declarative and Procedural Knowledge in Datasets and Large Language Models

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    Declarative knowledge and procedural knowledge are two key parts in meta-cognitive theory, and these two hold significant importance in pre-training and inference of LLMs. However, a comprehensive analysis comparing these two types of knowledge is lacking, primarily due to challenges in definition, probing and quantitative assessment. In this paper, we explore from a new perspective by providing ground-truth knowledge for LLMs and evaluating the effective score. Through extensive experiments with widely-used datasets and models, we get conclusions: (1) In most tasks, benefits from declarative knowledge are greater than those from procedural knowledge. (2) Profits of procedural knowledge are larger than declarative knowledge only in reasoning tasks with simple logic. (3) As pre-training progresses and size increases, model ability to utilize both kinds of knowledge significantly improves, but in different speed. We do detailed analysis for the findings and this can provide primary guidance for evaluation and enhancement of large language models.Comment: Accepted by LREC-COLING 2024 as a short pape

    FedComLoc: Communication-Efficient Distributed Training of Sparse and Quantized Models

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    Federated Learning (FL) has garnered increasing attention due to its unique characteristic of allowing heterogeneous clients to process their private data locally and interact with a central server, while being respectful of privacy. A critical bottleneck in FL is the communication cost. A pivotal strategy to mitigate this burden is \emph{Local Training}, which involves running multiple local stochastic gradient descent iterations between communication phases. Our work is inspired by the innovative \emph{Scaffnew} algorithm, which has considerably advanced the reduction of communication complexity in FL. We introduce FedComLoc (Federated Compressed and Local Training), integrating practical and effective compression into \emph{Scaffnew} to further enhance communication efficiency. Extensive experiments, using the popular TopK compressor and quantization, demonstrate its prowess in substantially reducing communication overheads in heterogeneous settings

    The Next Generation Virgo Cluster Survey (NGVS). XXVII.The Size and Structure of Globular Cluster Systems and their Connection to Dark Matter Halos

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    We study the size and structure of globular clusters (GC) systems of 118 early-type galaxies from the NGVS, MATLAS, and ACSVCS surveys. Fitting S\'ersic profiles, we investigate the relationship between effective radii of GC systems (Re,gcR_{e, \rm gc}) and galaxy properties. GC systems are 2--4 times more extended than host galaxies across the entire stellar mass range of our sample (108.3<M<1011.6 M10^{8.3} < M_* < 10^{11.6}~M_{\odot}). The relationship between Re,gcR_{e, \rm gc} and galaxy stellar mass exhibits a characteristic "knee" at a stellar mass of Mp1010.8M_p \simeq 10^{10.8}, similar to galaxy ReR_e--stellar mass relationship. We present a new characterization of the traditional blue and red GC color sub-populations, describing them with respect to host galaxy (gi)(g'-i') color (Δgi\Delta_{gi}): GCs with similar colors to their hosts have a "red" Δgi\Delta_{gi}, and those significantly bluer GCs have a "blue" Δgi\Delta_{gi}. The GC populations with red Δgi\Delta_{gi}, even in dwarf galaxies, are twice as extended as the stars, suggesting that formation or survival mechanisms favor the outer regions. We find a tight correlation between Re,gcR_{e, \rm gc} and the total number of GCs, with intrinsic scatter 0.1\lesssim 0.1 dex spanning two and three orders of magnitude in size and number, respectively. This holds for both red and blue subpopulations, albeit with different slopes. Assuming that NGC,TotalN_{GC, Total} correlates with M200M_{200}, we find that the red GC systems have effective radii of roughly 1-5\% R200R_{\rm 200}, while the blue GC systems in massive galaxies can have sizes as large as \sim10\% R200R_{\rm 200}. Environmental dependence on Re,gcR_{e, \rm gc} is also found, with lower density environments exhibiting more extended GC systems at fixed mass.Comment: 28 pages, 18 Figures, 3 tables, accepted for publication in Ap

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