9,085 research outputs found

    Assessing Human Error Against a Benchmark of Perfection

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    An increasing number of domains are providing us with detailed trace data on human decisions in settings where we can evaluate the quality of these decisions via an algorithm. Motivated by this development, an emerging line of work has begun to consider whether we can characterize and predict the kinds of decisions where people are likely to make errors. To investigate what a general framework for human error prediction might look like, we focus on a model system with a rich history in the behavioral sciences: the decisions made by chess players as they select moves in a game. We carry out our analysis at a large scale, employing datasets with several million recorded games, and using chess tablebases to acquire a form of ground truth for a subset of chess positions that have been completely solved by computers but remain challenging even for the best players in the world. We organize our analysis around three categories of features that we argue are present in most settings where the analysis of human error is applicable: the skill of the decision-maker, the time available to make the decision, and the inherent difficulty of the decision. We identify rich structure in all three of these categories of features, and find strong evidence that in our domain, features describing the inherent difficulty of an instance are significantly more powerful than features based on skill or time.Comment: KDD 2016; 10 page

    Kinetic theory for nongeodesic particle motion: Selfinteracting equilibrium states and effective viscous fluid pressures

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    The particles of a classical relativistic gas are supposed to move under the influence of a quasilinear (in the particle four-momenta), self-interacting force inbetween elastic, binary collisions. This force which is completely fixed by the equilibrium conditions of the gas, gives rise to an effective viscous pressure on the fluid phenomenological level. Earlier results concerning the possibility of accelerated expansion of the universe due to cosmological particle production are reinterpreted. A phenomenon such as power law inflation may be traced back to specific self-interacting forces keeping the particles of a gas universe in states of generalized equilibrium.Comment: 16 pages, latex, uses ioplppt.sty. To appear in Class. Quantum Gra

    Duality, thermodynamics, and the linear programming problem in constraint-based models of metabolism

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    It is shown that the dual to the linear programming problem that arises in constraint-based models of metabolism can be given a thermodynamic interpretation in which the shadow prices are chemical potential analogues, and the objective is to minimise free energy consumption given a free energy drain corresponding to growth. The interpretation is distinct from conventional non-equilibrium thermodynamics, although it does satisfy a minimum entropy production principle. It can be used to motivate extensions of constraint-based modelling, for example to microbial ecosystems.Comment: 4 pages, 2 figures, 1 table, RevTeX 4, final accepted versio

    Momentum of an electromagnetic wave in dielectric media

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    Almost a hundred years ago, two different expressions were proposed for the energy--momentum tensor of an electromagnetic wave in a dielectric. Minkowski's tensor predicted an increase in the linear momentum of the wave on entering a dielectric medium, whereas Abraham's tensor predicted its decrease. Theoretical arguments were advanced in favour of both sides, and experiments proved incapable of distinguishing between the two. Yet more forms were proposed, each with their advocates who considered the form that they were proposing to be the one true tensor. This paper reviews the debate and its eventual conclusion: that no electromagnetic wave energy--momentum tensor is complete on its own. When the appropriate accompanying energy--momentum tensor for the material medium is also considered, experimental predictions of all the various proposed tensors will always be the same, and the preferred form is therefore effectively a matter of personal choice.Comment: 23 pages, 3 figures, RevTeX 4. Removed erroneous factor of mu/mu_0 from Eq.(44

    Anomalous diffusion in viscosity landscapes

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    Anomalous diffusion is predicted for Brownian particles in inhomogeneous viscosity landscapes by means of scaling arguments, which are substantiated through numerical simulations. Analytical solutions of the related Fokker-Planck equation in limiting cases confirm our results. For an ensemble of particles starting at a spatial minimum (maximum) of the viscous damping we find subdiffusive (superdiffusive) motion. Superdiffusion occurs also for a monotonically varying viscosity profile. We suggest different substances for related experimental investigations.Comment: 15 page

    Can Dark Matter Decay in Dark Energy?

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    We analyze the interaction between Dark Energy and Dark Matter from a thermodynamical perspective. By assuming they have different temperatures, we study the possibility of occurring a decay from Dark Matter into Dark Energy, characterized by a negative parameter QQ. We find that, if at least one of the fluids has non vanishing chemical potential, for instance μx<0\mu_x<0 and μdm=0\mu_{dm}=0 or μx=0\mu_x=0 and μdm>0\mu_{dm}>0, the decay is possible, where μx\mu_x and μdm\mu_{dm} are the chemical potentials of Dark Energy and Dark Matter, respectively. Using recent cosmological data, we find that, for a fairly simple interaction, the Dark Matter decay is favored with a probability of 93\sim 93% over the Dark Energy decay. This result comes from a likelihood analysis where only background evolution has been considered.Comment: Matches the published version. Section V changed. Formalism and main conclusion unchange

    Buildings behaving badly:A behavioral experiment on how different motivational frames influence residential energy label adoption in the Netherlands

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    Heating buildings contributes to approximately 36% of Europe’s energy demand and several EU member states have adopted mandatory energy labels to improve energy efficiency by promoting home weatherization investments. This paper focuses on the perception of the energy label for residential buildings in the Netherlands and the role of different frames (egoistic, biospheric and social norms and neutral frames) in motivating adoption of energy labels for housing. We used a behavioral email experiment and an online survey to investigate these motivational factors. We find that biospheric frames are weaker than the other three motivational frames in terms of engaging interest in the energy label, but that the biospheric frame results in higher willingness to pay (WTP) for the energy label. We also find that age (rather than income) correlates with higher willingness to pay for home energy labels

    Foldy-Wouthyusen Transformation and Semiclassical Limit for Relativistic Particles in Strong External Fields

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    A general method of the Foldy-Wouthyusen (FW) transformation for relativistic particles of arbitrary spin in strong external fields has been developed. The use of the found transformation operator is not restricted by any definite commutation relations between even and odd operators. The final FW Hamiltonian can be expanded into a power series in the Planck constant which characterizes the order of magnitude of quantum corrections. Exact expressions for low-order terms in the Planck constant can be derived. Finding these expressions allows to perform a simple transition to the semiclassical approximation which defines a classical limit of the relativistic quantum mechanics. As an example, interactions of spin-1/2 and scalar particles with a strong electromagnetic field have been considered. Quantum and semiclassical equations of motion of particles and their spins have been deduced. Full agreement between quantum and classical theories has been established.Comment: 10 page

    Chemical Potential and the Nature of the Dark Energy: The case of phantom

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    The influence of a possible non zero chemical potential μ\mu on the nature of dark energy is investigated by assuming that the dark energy is a relativistic perfect simple fluid obeying the equation of state (EoS), p=ωρp=\omega \rho (ω<0,constant\omega <0, constant). The entropy condition, S0S \geq 0, implies that the possible values of ω\omega are heavily dependent on the magnitude, as well as on the sign of the chemical potential. For μ>0\mu >0, the ω\omega-parameter must be greater than -1 (vacuum is forbidden) while for μ<0\mu < 0 not only the vacuum but even a phantomlike behavior (ω<1\omega <-1) is allowed. In any case, the ratio between the chemical potential and temperature remains constant, that is, μ/T=μ0/T0\mu/T=\mu_0/T_0. Assuming that the dark energy constituents have either a bosonic or fermionic nature, the general form of the spectrum is also proposed. For bosons μ\mu is always negative and the extended Wien's law allows only a dark component with ω<1/2\omega < -1/2 which includes vacuum and the phantomlike cases. The same happens in the fermionic branch for μ0\mu 0 are permmited only if 1<ω<1/2-1 < \omega < -1/2. The thermodynamics and statistical arguments constrain the EoS parameter to be ω<1/2\omega < -1/2, a result surprisingly close to the maximal value required to accelerate a FRW type universe dominated by matter and dark energy (ω10/21\omega \lesssim -10/21).Comment: 7 pages, 5 figure

    Influence of rotational force fields on the determination of the work done on a driven Brownian particle

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    For a Brownian system the evolution of thermodynamic quantities is a stochastic process. In particular, the work performed on a driven colloidal particle held in an optical trap changes for each realization of the experimental manipulation, even though the manipulation protocol remains unchanged. Nevertheless, the work distribution is governed by established laws. Here, we show how the measurement of the work distribution is influenced by the presence of rotational, i.e. nonconservative, radiation forces. Experiments on particles of different materials show that the rotational radiation forces, and therefore their effect on the work distributions, increase with the particle refractive index.Comment: 12 pages, 4 figure
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