Learning semilinear sets from examples and via queries

AbstractSemilinear sets play an important role in parallel computation models such as matrix grammars, commutative grammars, and Petri nets. In this paper, we consider the problems of learning semilinear sets from examples and via queries. We shall show that (1) the family of semilinear sets is not learnable only from positive examples, while the family of linear sets is learnable only from positive examples, although the problem of learning linear sets from positive examples seems to be computationally intractable; (2) if for any unknown semilinear set Su and any conjectured semilinear set S′, queries whether or not Su⊆S′ and queries whether or not S′⊆Su can be made, there exists a learning procedure which identifies any semilinear set and halts, although the procedure is time-consuming; (3) however, under the same condition, for each fixed dimension, there exist meaningful subfamilies of semilinear sets learnable in polynomial time of the minimum size of representations and, in particular, for any variable dimension, if for any unknown linear set Lu and any conjectured semilinear set S′, queries whether or not Lu⊆S′ can be made, the family of linear sets is learnable in polynomial time of the minimum size of representations and the dimension

Evaluation of Driving-Assistance Systems Based on Drivers\u27 Workload

This paper describes an experimental study concerning an evaluation of advanced driving-assistance systems using methods for estimating workload levels. The effects of such systems on drivers’ mental workload and driving performance were measured experimentally using the driving simulator. Six subjects were instructed to drive the simulator in a highway environment with and without Adaptive Cruise Control (ACC) and/or the collision-warning system (CWS). To assess the effectiveness of these systems on drivers’ performance, the subjects were asked to calculate sums of single- or double-digit figures displayed. The results show that higher accuracy was obtained under a condition with ACC than without it. To estimate the subjects’ mental workload levels, their electrocardiograms and respiration data were recorded during the sessions and the RRI, heart rate variance and respiration frequency were calculated. The results indicate that the provision of the CWS and ACC reduced the subjects’ mental workload compared with the situation without the systems

Inferring pure context-free languages from positive data

We study the possibilities to infer pure context-free languages from positive data. We can show that while the whole class of pure context-free languages is not inferable from positive data, it has interesting subclasses which have the desired inference property. We study uniform pure languages, i.e., languages generated by pure grammars obeying restrictions on the length of the right hand sides of their productions, and pure languages generated by deterministic pure grammars

Non-LTE Line-Formation and Abundances of Sulfur and Zinc in F, G, and K Stars

Extensive statistical-equilibrium calculations on neutral sulfur and zinc were carried out, in order to investigate how the non-LTE effect plays a role in the determination of S and Zn abundances in F, G, and K stars. Having checked on the spectra of representative F-type stars (Polaris, Procyon, and alpha Per) and the Sun that our non-LTE corrections yield a reasonable consistency between the abundances derived from different lines, we tried an extensive non-LTE reanalysis of published equivalent-width data of S I and Zn I lines for metal-poor halo/disk stars. According to our calculations, S I 9212/9228/9237 lines suffer significant negative non-LTE corrections amounting to <~ 0.2--0.3 dex, while LTE is practically valid for S I 8683/8694 lines. Embarrassingly, as far as the very metal-poor regime is concerned, a marked discordance is observed between the [S/Fe] values from these two abundance indicators, in the sense that the former attains a nearly flat plateau (or even a slight downward bending) while the latter shows an ever-increasing trend with a further lowering of metallicity. The reason for this discrepancy is yet to be clarified. Regarding Zn, we almost confirmed the characteristic tendencies of [Zn/Fe] reported from recent LTE studies (i.e., an evident/slight increase of [Zn/Fe] with a decrease of [Fe/H] for very metal-poor/disk stars), since the non-LTE corrections for the Zn I 4722/4810 and 6362 lines (tending to be positive and gradually increasing towards lower [Fe/H]) are quantitatively of less significance (<~ 0.1 dex).Comment: 33 pages, 7 figures, PASJ, Vol. 57, No. 5 (2005) in pres

Theoretical Studies on the Dielectric Breakdown of the SiO_2 Thin Films

Electronic structures of oxygen deficiency in the SiO_2 thin film are theoretically studied by using the cluster models of Si_2O_7H_6 and Si_2O_6H_6 in order to reveal the mechanism of dielectric breakdown observed in the thin films. It is found that the oxygen deficiency induces electron traps rather than hole traps. Furthermore, F^- ions captured through the HF treatments are considered to be a key to introduce the oxygen deficiency in the SiO_2 thin films

Chemogenetic sensory fMRI reveals behaviorally relevant bidirectional changes in primate somatosensory network

手と足の感覚は、実は脳の中でつながっていた --脳障害による活動変化の広がりを見ることで常識を覆す発見、脳機能・疾患機序の理解へ前進--. 京都大学プレスリリース. 2021-10-21.Concurrent genetic neuromodulation and functional magnetic resonance imaging (fMRI) in primates has provided a valuable opportunity to assess the modified brain-wide operation in the resting state. However, its application to link the network operation with behavior still remains challenging. Here, we combined chemogenetic silencing of the primary somatosensory cortex (SI) with tactile fMRI and related behaviors in macaques. Focal chemogenetic silencing of functionally identified SI hand region impaired grasping behavior. The same silencing also attenuated hand stimulation-evoked fMRI signal at both the local silencing site and the anatomically and/or functionally connected downstream grasping network, suggesting altered network operation underlying the induced behavioral impairment. Furthermore, the hand region silencing unexpectedly disinhibited foot representation with accompanying behavioral hypersensitization. These results demonstrate that focal chemogenetic silencing with sensory fMRI in macaques unveils bidirectional network changes to generate multifaceted behavioral impairments, thereby opening a pivotal window toward elucidating the causal network operation underpinning higher brain functions in primates