14,423 research outputs found

    On information captured by neural networks: connections with memorization and generalization

    Full text link
    Despite the popularity and success of deep learning, there is limited understanding of when, how, and why neural networks generalize to unseen examples. Since learning can be seen as extracting information from data, we formally study information captured by neural networks during training. Specifically, we start with viewing learning in presence of noisy labels from an information-theoretic perspective and derive a learning algorithm that limits label noise information in weights. We then define a notion of unique information that an individual sample provides to the training of a deep network, shedding some light on the behavior of neural networks on examples that are atypical, ambiguous, or belong to underrepresented subpopulations. We relate example informativeness to generalization by deriving nonvacuous generalization gap bounds. Finally, by studying knowledge distillation, we highlight the important role of data and label complexity in generalization. Overall, our findings contribute to a deeper understanding of the mechanisms underlying neural network generalization.Comment: PhD thesi

    Galaxy cluster mass accretion rates from IllustrisTNG

    Full text link
    We use simulated cluster member galaxies from Illustris TNG300-1 to develop a technique for measuring the galaxy cluster mass accretion rate (MAR) that can be applied directly to observations. We analyze 1318 IllustrisTNG clusters of galaxies with M200c>1014M_{200c}>10^{14}M⊙_\odot and 0.01≀z≀1.040.01\leq z \leq 1.04. The MAR we derive is the ratio between the mass of a spherical shell located in the infall region and the time for the infalling shell to accrete onto the cluster core. At fixed redshift, an ∌1\sim 1 order of magnitude increase in M200cM_{200c} results in a comparable increase in MAR. At fixed mass, the MAR increases by a factor of ∌5\sim 5 from z=0.01z=0.01 to z=1.04z=1.04. The MAR estimates derived from the caustic technique are unbiased and lie within 20% of the MAR's based on the true mass profiles. This agreement is crucial for observational derivation of the MAR. The IllustrisTNG results are also consistent with (i) previous merger tree approaches based on N-body dark matter only simulations and with (ii) previously determined MAR's of real clusters based on the caustic method. Future spectroscopic and photometric surveys will provide MAR's of enormous cluster samples with mass profiles derived from both spectroscopy and weak lensing. Combined with future larger volume hydrodynamical simulations that extend to higher redshift, the MAR promises important insights into evolution of massive systems of galaxies.Comment: 13 pagers, 13 figures, 4 tables. Submitted to A&

    A Logic-Based Analysis of Responsibility

    Full text link
    This paper presents a logic-based framework to analyze responsibility, which I refer to as intentional epistemic act-utilitarian stit theory (IEAUST). To be precise, IEAUST is used to model and syntactically characterize various modes of responsibility, where by 'modes of responsibility' I mean instances of Broersen's three categories of responsibility (causal, informational, and motivational responsibility), cast against the background of particular deontic contexts. IEAUST is obtained by integrating a modal language to express the following components of responsibility on stit models: agency, epistemic notions, intentionality, and different senses of obligation. With such a language, I characterize the components of responsibility using particular formulas. Then, adopting a compositional approach -- where complex modalities are built out of more basic ones -- these characterizations of the components are used to formalize the aforementioned modes of responsibility.Comment: In Proceedings TARK 2023, arXiv:2307.0400

    Comparative Multiple Case Study into the Teaching of Problem-Solving Competence in Lebanese Middle Schools

    Get PDF
    This multiple case study investigates how problem-solving competence is integrated into teaching practices in private schools in Lebanon. Its purpose is to compare instructional approaches to problem-solving across three different programs: the American (Common Core State Standards and New Generation Science Standards), French (Socle Commun de Connaissances, de Compétences et de Culture), and Lebanese with a focus on middle school (grades 7, 8, and 9). The project was conducted in nine schools equally distributed among three categories based on the programs they offered: category 1 schools offered the Lebanese program, category 2 the French and Lebanese programs, and category 3 the American and Lebanese programs. Each school was treated as a separate case. Structured observation data were collected using observation logs that focused on lesson objectives and specific cognitive problem-solving processes. The two logs were created based on a document review of the requirements for the three programs. Structured observations were followed by semi-structured interviews that were conducted to explore teachers' beliefs and understandings of problem-solving competence. The comparative analysis of within-category structured observations revealed an instruction ranging from teacher-led practices, particularly in category 1 schools, to more student-centered approaches in categories 2 and 3. The cross-category analysis showed a reliance on cognitive processes primarily promoting exploration, understanding, and demonstrating understanding, with less emphasis on planning and executing, monitoring and reflecting, thus uncovering a weakness in addressing these processes. The findings of the post-observation semi-structured interviews disclosed a range of definitions of problem-solving competence prevalent amongst teachers with clear divergences across the three school categories. This research is unique in that it compares problem-solving teaching approaches across three different programs and explores underlying teachers' beliefs and understandings of problem-solving competence in the Lebanese context. It is hoped that this project will inform curriculum developers about future directions and much-anticipated reforms of the Lebanese program and practitioners about areas that need to be addressed to further improve the teaching of problem-solving competence

    Energy Supplies in the Countries from the Visegrad Group

    Get PDF
    The purpose of this Special Issue was to collect and present research results and experiences on energy supply in the Visegrad Group countries. This research considers both macroeconomic and microeconomic aspects. It was important to determine how the V4 countries deal with energy management, how they have undergone or are undergoing energy transformation and in what direction they are heading. The articles concerned aspects of the energy balance in the V4 countries compared to the EU, including the production of renewable energy, as well as changes in its individual sectors (transport and food production). The energy efficiency of low-emission vehicles in public transport and goods deliveries are also discussed, as well as the energy efficiency of farms and energy storage facilities and the impact of the energy sector on the quality of the environment

    Vitalism and Its Legacy in Twentieth Century Life Sciences and Philosophy

    Get PDF
    This Open Access book combines philosophical and historical analysis of various forms of alternatives to mechanism and mechanistic explanation, focusing on the 19th century to the present. It addresses vitalism, organicism and responses to materialism and its relevance to current biological science. In doing so, it promotes dialogue and discussion about the historical and philosophical importance of vitalism and other non-mechanistic conceptions of life. It points towards the integration of genomic science into the broader history of biology. It details a broad engagement with a variety of nineteenth, twentieth and twenty-first century vitalisms and conceptions of life. In addition, it discusses important threads in the history of concepts in the United States and Europe, including charting new reception histories in eastern and south-eastern Europe. While vitalism, organicism and similar epistemologies are often the concern of specialists in the history and philosophy of biology and of historians of ideas, the range of the contributions as well as the geographical and temporal scope of the volume allows for it to appeal to the historian of science and the historian of biology generally

    Thomas Hobbes and the phenomena of civil war: A textual exposition of Hobbes’s commitment to the empirical and historical existence of the state of nature.

    Get PDF
    Did Thomas Hobbes consider his conception of the state of nature to be based within any empirically verifiable reality? The foundational predicates of this thesis can be reduced to two fundamental points: 1. That Hobbes’s belief in the existence in the state of nature was sincere. 2. The most pertinent empirical basis for the state of nature expressed by Hobbes was civil war, specifically, the English Civil War Period. The analytical trajectory of the thesis will endeavour, whenever possible, to pursue channels of inquiry which correspond to the two key predicates adumbrated above. The format has been styled as a “textual exposition” because the method endorsed will seek to expose Hobbes’s commitment to the existence of the state of nature from the words that he himself had written. Whether they be elements of his renowned philosophical system, or written material situated outside the terminus of his political science. Such as his correspondence, or lesser-known publications. Secondary material written about Hobbes’s state of nature, and the judgments of such authors as created them will of course be consulted at various points. However, to the primary material, containing Hobbes’s own judgments on the state of nature and its relationship with civil war, is accorded the greater responsibility for validating the premises of this thesis

    From the Hardness of Detecting Superpositions to Cryptography: Quantum Public Key Encryption and Commitments

    Full text link
    Recently, Aaronson et al. (arXiv:2009.07450) showed that detecting interference between two orthogonal states is as hard as swapping these states. While their original motivation was from quantum gravity, we show its applications in quantum cryptography. 1. We construct the first public key encryption scheme from cryptographic \emph{non-abelian} group actions. Interestingly, the ciphertexts of our scheme are quantum even if messages are classical. This resolves an open question posed by Ji et al. (TCC '19). We construct the scheme through a new abstraction called swap-trapdoor function pairs, which may be of independent interest. 2. We give a simple and efficient compiler that converts the flavor of quantum bit commitments. More precisely, for any prefix X,Y ∈\in {computationally,statistically,perfectly}, if the base scheme is X-hiding and Y-binding, then the resulting scheme is Y-hiding and X-binding. Our compiler calls the base scheme only once. Previously, all known compilers call the base schemes polynomially many times (Cr\'epeau et al., Eurocrypt '01 and Yan, Asiacrypt '22). For the security proof of the conversion, we generalize the result of Aaronson et al. by considering quantum auxiliary inputs.Comment: 51 page

    The Impossibility of Approximate Agreement on a Larger Class of Graphs

    Get PDF
    Approximate agreement is a variant of consensus in which processes receive input values from a domain and must output values in that domain that are sufficiently close to one another. We study the problem when the input domain is the vertex set of a connected graph. In asynchronous systems where processes communicate using shared registers, there are wait-free approximate agreement algorithms when the graph is a path or a tree, but not when the graph is a cycle of length at least 4. For many graphs, it is unknown whether a wait-free solution for approximate agreement exists. We introduce a set of impossibility conditions and prove that approximate agreement on graphs satisfying these conditions cannot be solved in a wait-free manner. In particular, the graphs of all triangulated d-dimensional spheres that are not cliques, satisfy these conditions. The vertices and edges of an octahedron is an example of such a graph. We also present a family of reductions from approximate agreement on one graph to another graph. This allows us to extend known impossibility results to even more graphs
    • 

    corecore