Hasil untuk "History (General)"

Francesco Vissani

The concept of antimatter is extremely important, but not always discussed as it deserves, balancing ideas and formalism. In this note, we gather some insights to present it effectively, following certain steps taken in the history of knowledge; although rarely remembered, they can serve to enrich standard teaching materials. In addition to the well-known contributions of Dirac, which we place in their original context, the contributions of Pauli and especially Majorana stand out, the latter being the first to reach the modern formalism of canonical quantization. The importance of the point of view of wave mechanics emerges, which still shows its limitations, requiring some adjustments to constitute an acceptable interpretation.

Thomas Preskett, Marco Virgilio, Prateek Jaiswal et al.

Experiments are conducted over smooth and rough walls to explore the influence of pressure gradient histories on skin friction and mean flow of turbulent boundary layers. Different pressure gradient histories are imposed on the boundary layer through an aerofoil mounted in the freestream. Hot-wire measurements are taken at different freestream velocities downstream of the aerofoil where the flow has locally recovered to zero pressure gradient but retains the history effects. Direct skin friction measurements are also made using oil film interferometry for smooth walls and a floating element drag balance for rough walls. The friction Reynolds number, $Re_τ$, varies between $3000$ and $27000$, depending both on the surface conditions and the freestream velocity ensuring sufficient scale separation. Results align with previous findings, showing that adverse pressure gradients just upstream of the measurement location increase wake strength and reduce the local skin friction while favourable pressure gradients suppress the wake and increase skin friction. The roughness length scale, $y_0$, remains constant across different pressure gradient histories for rough wall boundary layers. Inspired by previous works, a new correlation is proposed to infer skin friction based on the mean flow. The difference in skin friction between an arbitrary pressure gradient history and zero pressure gradient condition can be predicted using only the local wake strength parameter ($Π$), and the variations in wake strength for different histories are related to a weighted integral of the pressure gradient history normalised by local quantities. This allows us to develop a general correlation that can be used to infer skin friction for turbulent boundary layers experiencing arbitrary pressure-gradient histories.

Yu Liu, Wenwen Li, Yifan Dou et al.

As artificial intelligence (AI) enters the agentic era, large language models (LLMs) are increasingly deployed as autonomous agents that interact with one another rather than operate in isolation. This shift raises a fundamental question: how do machine agents behave in interdependent environments where outcomes depend not only on their own choices but also on the coordinated expectations of peers? To address this question, we study LLM agents in a canonical network-effect game, where economic theory predicts convergence to a fulfilled expectation equilibrium (FEE). We design an experimental framework in which 50 heterogeneous GPT-5-based agents repeatedly interact under systematically varied network-effect strengths, price trajectories, and decision-history lengths. The results reveal that LLM agents systematically diverge from FEE: they underestimate participation at low prices, overestimate at high prices, and sustain persistent dispersion. Crucially, the way history is structured emerges as a design lever. Simple monotonic histories-where past outcomes follow a steady upward or downward trend-help stabilize coordination, whereas nonmonotonic histories amplify divergence and path dependence. Regression analyses at the individual level further show that price is the dominant driver of deviation, history moderates this effect, and network effects amplify contextual distortions. Together, these findings advance machine behavior research by providing the first systematic evidence on multi-agent AI systems under network effects and offer guidance for configuring such systems in practice.

Qiaorong S. Yu, Stephanie O'Neil, Xuejian Shen et al.

In this study, we define the novel splashback depth $\mathcal{D}$ and width $\mathcal{W}$ to examine how the splashback features of dark matter haloes are affected by the physical properties of haloes themselves. We use the largest simulation run in the hydrodynamic MillenniumTNG project. By stacking haloes in bins of halo mass, redshift, mass-dependent properties such as peak height and concentration, and halo formation history, we measure the shape of the logarithmic slope of the density profile of dark matter haloes. Our results show that the splashback depth has a strong dependence on the halo mass which follows a power law $\mathcal{D}\propto\left(\log_{10}M\right)^{2.8}$. Properties with strong correlation with halo mass demonstrate similar dependence. The splashback width has the strongest dependence on halo peak height and follows a power law $\mathcal{W}\proptoν^{-0.87}$. We provide the fitting functions of the splashback depth and width in terms of halo mass, redshift, peak height, concentrations and halo formation time. The depth and width are therefore considered to be a long term memory tracker of haloes since they depend more on accumulative physical properties, e.g., halo mass, peak height and halo formation time. They are shaped primarily by the halo's assembly history, which exerts a stronger influence on the inner density profile than short-term dynamical processes. In contrast, the splashback features have little dependence on the short term factors such as halo mass accretion rate and most recent major merger time. The splashback depth and width can therefore be used to complement information gained from quantities like the point of steepest slope or truncation radius to characterise the halo's history and inner structure.

Qishuai Zhong, Zongmin Li, Siqi Fan et al.

Effective engagement by large language models (LLMs) requires adapting responses to users' sociodemographic characteristics, such as age, occupation, and education level. While many real-world applications leverage dialogue history for contextualization, existing evaluations of LLMs' behavioral adaptation often focus on single-turn prompts. In this paper, we propose a framework to evaluate LLM adaptation when attributes are introduced either (1) explicitly via user profiles in the prompt or (2) implicitly through multi-turn dialogue history. We assess the consistency of model behavior across these modalities. Using a multi-agent pipeline, we construct a synthetic dataset pairing dialogue histories with distinct user profiles and employ questions from the Value Survey Module (VSM 2013) (Hofstede and Hofstede, 2016) to probe value expression. Our findings indicate that most models adjust their expressed values in response to demographic changes, particularly in age and education level, but consistency varies. Models with stronger reasoning capabilities demonstrate greater alignment, indicating the importance of reasoning in robust sociodemographic adaptation.

Rubén García-Benito

The International Conference on Auditory Display (ICAD) is a significant event for researchers and practitioners interested in exploring the use of sound in conveying information and data. Since its inception in 1994, the conference has served as a vital forum for exchanging ideas and presenting research findings in the field of auditory display. While the conference primarily focuses on auditory display and sound design, astronomy has made its presence felt in the proceedings of the conference over the years. However, its not until the current ICAD conference where astronomy features a dedicated session. This paper aims to provide an statistical overview of the presence of astronomy in the ICAD conference's history from 1994 to 2022, highlighting some of the contributions made by researchers in this area, as well as the topics of interest that have captured the attention of sound artists.

Rik Koncel-Kedziorski, Noah A. Smith

We introduce a technique for improving document-level language models (LM) by leveraging "ancient history": text that is outside the LM's current context window. We learn an auxiliary function to select spans from the ancient history which can help the LM to predict future text. The selected text spans are then copied directly into the LM's context window, replacing less predictive spans. This method can improve perplexity of pretrained LMs with no updates to the LM's own parameters. We further observe that an auxiliary function trained in a specific textual domain like Wikipedia will also work in a substantially different domain such as scientific publications. With this technique we see a 7 percent perplexity reduction on Wikipedia articles, and a 12 percent perplexity reduction on scientific texts.

Johnny Seales, Adrian Lenardic

Multiple hypotheses/models have been put forward regarding the cooling history of the Earth. The search for life beyond Earth has brought these models into a new light as they connect to one of the two energy sources life can tap. The ability to discriminate between different Earth cooling models, and the utility of adopting such models to aid in the assessment of planetary habitability, has been hampered by a lack of uncertainty analysis. This motivates a layered uncertainty analysis for a range of thermal history models that have been applied to the Earth. The analysis evaluates coupled model input, initial condition, and structural uncertainty. Layered model uncertainty, together with data uncertainty and multiple working hypotheses (another form of uncertainty), means that results must be evaluated in a probabilistic sense even if the models are deterministic. For the Earth's cooling history uncertainty leads to ambiguity - multiple models, based on different hypotheses, can match data constraints. This has implications for using such models to forecast conditions for exoplanets that share Earth characteristics but are older than the Earth, i.e., it has implications for modeling the long-term life potential of terrestrial planets. Even for the most Earth-like planet we know of, the Earth itself, model uncertainty and ambiguity leads to large forecast spreads. Given that this comes from the planet with the most data constraints we should expect larger spreads for models of terrestrial planets in general. The layered uncertainty approach can be expanded by coupling planetary cooling models to climate models and propagating uncertainty between them to assess habitability from a probabilistic versus a binary view.

Marcelo Losada, Roberto Laura, Olimpia Lombardi

In this article we reconstruct the Frauchiger and Renner argument, taking into account that the assertions of the argument are made at different times. To do this, we use a formalism of quantum histories, namely the Theory of Consistent Histories. We show that the supposedly contradictory conclusion of the argument requires computing probabilities in a family of histories that does not satisfy the consistency condition, i.e., an invalid family of histories for the theory.

Claudia Miller, Hamidreza Rahmati, Rebecca R. G

The main goal of this paper is to prove, in positive characteristic $p$, stability behavior for the graded Betti numbers in the periodic tails of the minimal resolutions of Frobenius powers of the homogeneous maximal ideals for very general choices of hypersurface in three variables whose degree has the opposite parity to that of $p$. We also find some of the structure of the matrix factorization giving the resolution. We achieve this by developing a method for obtaining the degrees of the generators of the defining ideal of an $\mathfrak{c}$-compressed Gorenstein Artinian graded algebra from its socle degree, where $\mathfrak{c}$ is a Frobenius power of the homogeneous maximal ideal. As an application, we also obtain the Hilbert-Kunz function of the hypersurface ring, as well as the Castelnuovo-Mumford regularity of the quotients by Frobenius powers of the homogeneous maximal ideal.

Clement Etienam

The work discussed and presented in this paper focuses on the history matching of reservoirs by integrating 4D seismic data into the inversion process using machine learning techniques. A new integrated scheme for the reconstruction of petrophysical properties with a modified Ensemble Smoother with Multiple Data Assimilation (ES-MDA) in a synthetic reservoir is proposed. The permeability field inside the reservoir is parametrised with an unsupervised learning approach, namely K-means with Singular Value Decomposition (K-SVD). This is combined with the Orthogonal Matching Pursuit (OMP) technique which is very typical for sparsity promoting regularisation schemes. Moreover, seismic attributes, in particular, acoustic impedance, are parametrised with the Discrete Cosine Transform (DCT). This novel combination of techniques from machine learning, sparsity regularisation, seismic imaging and history matching aims to address the ill-posedness of the inversion of historical production data efficiently using ES-MDA. In the numerical experiments provided, I demonstrate that these sparse representations of the petrophysical properties and the seismic attributes enables to obtain better production data matches to the true production data and to quantify the propagating waterfront better compared to more traditional methods that do not use comparable parametrisation techniques.

Miguel Couceiro

In this paper we focus on functions of the form $A^n\rightarrow \mathcal{P}(B)$, for possibly different arbitrary non-empty sets $A$ and $B$, and where $\mathcal{P}(B)$ denotes the set of all subsets of $B$. These mappings are called \emph{multivalued functions}, and they generalize total and partial functions. We study Galois connections between these generalized functions and ordered pairs $(R,S)$ of relations on $A$ and $B$, respectively, called \emph{constraints}. We describe the Galois closed sets, and decompose the associated Galois operators, by means of necessary and sufficient conditions which specialize, in the total single-valued case, to those given in the author's previous work [M. Couceiro, S. Foldes. On closed sets of relational constraints and classes of functions closed under variable substitutions, Algebra Universalis 54 (2005) 149-165].

Abdel Nasser Tawfik, Abdel Magied Diab

Based on string theory, black hole physics, doubly special relativity and some "thought" experiments, minimal distance and/or maximum momentum are proposed. As alternatives to the generalized uncertainty principle (GUP), the modified dispersion relation, the space noncommutativity, the Lorentz invariance violation, and the quantum-gravity-induced birefringence effects are summarized. The origin of minimal measurable quantities and the different GUP approaches are reviewed and the corresponding observations are analysed. Bounds on the GUP parameter are discussed and implemented in understanding recent PLANCK observations on the cosmic inflation. The higher-order GUP approaches predict minimal length uncertainty with and without maximum momenta.

Marion Erpelding, Santanu Sinha, Ken Tore Tallakstad et al.

It is well known that the transient behavior during drainage or imbibition in multiphase flow in porous media strongly depends on the history and initial condition of the system. However, when the steady-state regime is reached and both drainage and imbibition take place at the pore level, the influence of the evolution history and initial preparation is an open question. Here, we present an extensive experimental and numerical work investigating the history dependence of simultaneous steady-state two-phase flow through porous media. Our experimental system consists of a Hele-Shaw cell filled with glass beads which we model numerically by a network of disordered pores transporting two immiscible fluids. From the measurements of global pressure evolution, histogram of saturation and cluster-size distributions, we find that when both phases are flowing through the porous medium, the steady state does not depend on the initial preparation of the system or on the way it has been reached.

Andres Moreno-Estrada, Simon Gravel, Fouad Zakharia et al.

The Caribbean basin is home to some of the most complex interactions in recent history among previously diverged human populations. Here, by making use of genome-wide SNP array data, we characterize ancestral components of Caribbean populations on a sub-continental level and unveil fine-scale patterns of population structure distinguishing insular from mainland Caribbean populations as well as from other Hispanic/Latino groups. We provide genetic evidence for an inland South American origin of the Native American component in island populations and for extensive pre-Columbian gene flow across the Caribbean basin. The Caribbean-derived European component shows significant differentiation from parental Iberian populations, presumably as a result of founder effects during the colonization of the New World. Based on demographic models, we reconstruct the complex population history of the Caribbean since the onset of continental admixture. We find that insular populations are best modeled as mixtures absorbing two pulses of African migrants, coinciding with early and maximum activity stages of the transatlantic slave trade. These two pulses appear to have originated in different regions within West Africa, imprinting two distinguishable signatures in present day Afro-Caribbean genomes and shedding light on the genetic impact of the dynamics occurring during the slave trade in the Caribbean.

Pablo Aragón, Andreas Kaltenbrunner, David Laniado et al.

It is arguable whether history is made by great men and women or vice versa, but undoubtably social connections shape history. Analysing Wikipedia, a global collective memory place, we aim to understand how social links are recorded across cultures. Starting with the set of biographies in the English Wikipedia we focus on the networks of links between these biographical articles on the 15 largest language Wikipedias. We detect the most central characters in these networks and point out culture-related peculiarities. Furthermore, we reveal remarkable similarities between distinct groups of language Wikipedias and highlight the shared knowledge about connections between persons across cultures.

E. Minguzzi

A cosmological model is proposed which uses a causality argument to solve the homogeneity and entropy problems of cosmology. In this model a chronology violating region of spacetime causally precedes the remainder of the Universe, and a theorem establishes the existence of time functions precisely outside the chronology violating region. This model is shown to nicely reproduce Augustine of Hippo's thought on time and the beginning of the Universe. In the model the spacelike boundary representing the Big Bang is replaced by a null hypersurface at which the gravitational degrees of freedom are almost frozen while the matter and radiation content is highly homogeneous and thermalized.

M. Anyon, J. Dunning-Davies

A brief outline of the history of the discrepancies within Newtonian mechanics at the end of the nineteenth century is given. The framework of general relativity is described briefly and the famous 'tests' of general relativity are considered and alternative solutions discussed, with particular attention concentrating on the advance of the perihelion of the planet Mercury. The implications for the claims of relativity are discussed, all with reference to both pre and post 1915 publications.

Piero Madau

I review some recent progress made in our understanding of galaxy evolution and the cosmic history of star formation. Like bookends, the results obtained from deep ground-based spectroscopy and from the Hubble Deep Field imaging survey put brackets around the intermediate redshift interval, $1<z<2$, where starbirth probably peaked at a rate 10 times higher than today. The steady decline observed since $z\sim 1$ is largely associated with late-type galaxies. At $z\gtrsim 2.5$, the Lyman-break selected objects may represent the precursors of present-day spheroids, but appear, on average, quite underluminous relative to the expectations of the standard early-and-rapidly forming picture for spheroidal systems. The observed ultraviolet light density accounts for the bulk of the metals seen today in ``normal'' massive galaxies.

Gian Luigi Granato

I review recent advances in the determination of the cosmic history of star formation, and its relevance in our understanding of the formation of structures. I emphasize the importance of dust reprocessing in the high--z universe, as demonstrated in particular by IR and sub-mm data. This demand a panchromatic approach to observations and suitable modelling tools. I summarize the basic requirements for these models and to what extent they are satisfied by models published so far.