Optimal utility and probability functions for agents with finite computational precision

When making economic choices, such as those between goods or gambles, humans act as if their internal representation of the value and probability of a prospect is distorted away from its true value. These distortions give rise to decisions which apparently fail to maximize reward, and preferences that reverse without reason. Why would humans have evolved to encode value and probability in a distorted fashion, in the face of selective pressure for reward-maximizing choices? Here, we show that under the simple assumption that humans make decisions with finite computational precision––in other words, that decisions are irreducibly corrupted by noise––the distortions of value and probability displayed by humans are approximately optimal in that they maximize reward and minimize uncertainty. In two empirical studies, we manipulate factors that change the reward-maximizing form of distortion, and find that in each case, humans adapt optimally to the manipulation. This work suggests an answer to the longstanding question of why humans make “irrational” economic choices

New membership determination and proper motions of NGC 1817. Parametric and non-parametric approach

We have calculated proper motions and re-evaluated the membership probabilities of 810 stars in the area of two NGC objects, NGC 1817 and NGC 1807. We have obtained absolute proper motions from 25 plates in the reference system of the Tycho-2 Catalogue. The plates have a maximum epoch difference of 81 years; and they were taken with the double astrograph at Zo-Se station of Shanghai Observatory, which has an aperture of 40 cm and a plate scale of 30 arcsec/mm. The average proper motion precision is 1.55 mas/yr. These proper motions are used to determine the membership probabilities of stars in the region, based on there being only one very extended physical cluster: NGC 1817. With that aim, we have applied and compared parametric and non-parametric approaches to cluster/field segregation. We have obtained a list of 169 probable member stars.Comment: 11 pages, 8 figures, A&A in pres

Optimal sampling pattern for free final time linear quadratic regulator: the scalar case

The optimal sampling problem is the selection of the optimal sampling instants together with the optimal control actions such that a given cost function is minimized. In this article we solve the optimal sampling problem for free final time linear quadratic regulator with scalar dynamical system. The solution provides the optimal sampling instants, control actions, and the optimal final time in a recursive and constructive way for any arbitrary number of samples N ≥ 1, as it is not based on asymptotic arguments. An application example shows the feasibility of the approach

Co-creation and learning: an assessment of the pedagogical proposals in collaborative interactive non-fiction

Audiovisual co-creation has always had a pedagogical nature, which has been maintained in its adaptation to digital communication, although it is applied in different ways. This study analyses the pedagogical proposals in collaborative interactive non-fiction in the digital environment, and compares them with previous projects of participatory practices. As case studies we selected five interactive audiovisual projects that stand out for their educational intent and their preparation of teaching resources, and analyzed their pedagogical proposals. First, we looked at pedagogy in pre-digital or analogical collaborative creation, which was used to develop an original analytical table. We used this table to study the five collaborative projects through three identified categories. The results show that these categories continue in initiatives today, although the findings show a shift in the pedagogy about audiovisuals, particularly concerning the technical aspects, as well as a weakening of the connection between learning and participation in the collective production. Finally, we can highlight that combining educational practices with collaborative production on the Internet is important to increase citizen participation and give a social perspective to this audiovisual modality

Can we identify non-stationary dynamics of trial-to-trial variability?"

Identifying sources of the apparent variability in non-stationary scenarios is a fundamental problem in many biological data analysis settings. For instance, neurophysiological responses to the same task often vary from each repetition of the same experiment (trial) to the next. The origin and functional role of this observed variability is one of the fundamental questions in neuroscience. The nature of such trial-to-trial dynamics however remains largely elusive to current data analysis approaches. A range of strategies have been proposed in modalities such as electro-encephalography but gaining a fundamental insight into latent sources of trial-to-trial variability in neural recordings is still a major challenge. In this paper, we present a proof-of-concept study to the analysis of trial-to-trial variability dynamics founded on non-autonomous dynamical systems. At this initial stage, we evaluate the capacity of a simple statistic based on the behaviour of trajectories in classification settings, the trajectory coherence, in order to identify trial-to-trial dynamics. First, we derive the conditions leading to observable changes in datasets generated by a compact dynamical system (the Duffing equation). This canonical system plays the role of a ubiquitous model of non-stationary supervised classification problems. Second, we estimate the coherence of class-trajectories in empirically reconstructed space of system states. We show how this analysis can discern variations attributable to non-autonomous deterministic processes from stochastic fluctuations. The analyses are benchmarked using simulated and two different real datasets which have been shown to exhibit attractor dynamics. As an illustrative example, we focused on the analysis of the rat's frontal cortex ensemble dynamics during a decision-making task. Results suggest that, in line with recent hypotheses, rather than internal noise, it is the deterministic trend which most likely underlies the observed trial-to-trial variability. Thus, the empirical tool developed within this study potentially allows us to infer the source of variability in in-vivo neural recordings

Qualification and Start of Production of the Ultrasonic Welding Machines for the LHC Interconnections

The Large Hadron Collider (LHC) is presently under installation at CERN, Geneva. The approximately 4000 superconducting corrector magnets required by the machine are powered through copper-stabilized Nb-Ti busbars. To interconnect the magnets along the machine, about 50 000 joints between superconducting cables rated at 600 A have to be performed in-situ during the interconnection activities. An ultrasonic welding technique has been developed and optimised by CERN which led to the development of a dedicated machine which was qualified during the assembly of the STRING II, a 110-m chain of cryomagnets assembled as a prototype of the LHC. The realization of the â series â interconnections together with the procurement of the tooling based on functional specifications have been contracted to a consortium of firms. Qualification tests and acceptance criteria in terms of electrical contact resistance, mechanical resistance, reliability and reproducibility have been defined by CERN. This paper presents the tests and some results of the qualification process relevant to the industrialized tooling provided by the contractor. Results of pre-series junctions done in the LHC tunnel are presented together with the perspective for the continuation of the work

Freqüència, magnitud i escala en la morfodinàmica de les costes rocoses: observacions a s'Alavern (S de Mallorca, Mediterrània occidental)

S'avalua la magnitud dels processos erosius que actuen sobre els penya-segats carbonatats de s'Alavern (Sud de Mallorca) alhora que es detallen les seves components temporals i d'escala. Així el debat actual en geomorfologia litoral sobre la preponderància dels agents marins (acció hidràulica i mecànica) sobre els subaeris a d'alteració a viceversa (alteració física-química-biològica i moviment de masses) queda condicionat per l'escala temporal i l'efecte sobre el relleu. Mentre que a s'Alavem les taxes de denudació globals són de l'ordre de 0,004 a 0,310, les taxes de bioerosió per a les comunitats de gasteròpodes de Melaraphe neritoides i per al conjunt de pegellides -majoritàriament Patella rustica- són de 0,007 i 0,369. Els texts d'exposició aboquen taxes d'erosió on no hi participa l'abrasió entre 0,l8 i 0,50 en funció de la posició respecte a la línia de costa. Les taxes de disgregació granular de la façana del penya-segat de s' Alavern són de l'ordre de 0,117 amb una evident relació amb els episodis de pluges intenses i forts vents. Els moviments de masses han implicat la caiguda de fragments del penya-segat suposa volums d'esbaldregalls al voltant de 40 m', mentre que el trencament de fragments de la plataforma varia de 0,86 m' a 10m'. Tot plegat ens ajuda a construir un vector negatiu a un gràfic on contrastam la freqüència (escala temporal) i la magnitud (escala de volum) de retrocés de la costa rocosa, tot posant de manifest que el debat dels agents a processos marins VS. l'alteració és un artefacte que depèn únicament i exclusiva de l'escala d'anàlisi i de la posició dels investigadors en la sistematització de les seves observacions. A la vegada el vector que relaciona freqüència i magnitud ens planteja l'escenari òptim per relacionar els estudis de morfodinàmica de les costes rocoses amb les aproximacions de tipus evolutiu.The goal of this paper is to assess the role of erosion processes at s'Alavern sea cliffs pointing up the temporal and scale components of erosian rates. Thus the current debat concerning with the main role of wave processes (hydraulic and mechanic action) vs. subaerial and weathering (physical, chemical and biological weathering and mass movements) is overtrhusted by the analysis of the temporal and influence on landform of each process. At s' Alvavern denudation rates obtained through laser scanner and MEM range from 0.004 to 0.310, bioerosion mean rates by small snails (Melaraphe neritoides) or limpets (mainly Patella rustica) are respectively of O.007 and 0.369. On the other hand, exposition tests offer erosion rates from 0.18 to 0.50 according to their position across the shore platform. Sediment traps inform us about granular disintegration close to 0.117 triggered by rainfall episodes, seabrezees and winds. Finally, mass movement can imply from cliffwall falls of40 m'to shore rock platform fragments detachment of 0.86 to 10m'. All these erosion rates represented in a frequency vs. magnitude graph help to build a negative vector that point up that the debate on the main role of marine vs. subaerial processes is an artefact because much of the arguments of authors correspond to their position on temporal and spatial scale analysis. Also this vector, relating frequency and magnitude, can help rock coast geomorphologists to link the morphodynamical approach to the evolution approach to the rock coast