Spatial Concept Acquisition for a Mobile Robot that Integrates Self-Localization and Unsupervised Word Discovery from Spoken Sentences

In this paper, we propose a novel unsupervised learning method for the lexical acquisition of words related to places visited by robots, from human continuous speech signals. We address the problem of learning novel words by a robot that has no prior knowledge of these words except for a primitive acoustic model. Further, we propose a method that allows a robot to effectively use the learned words and their meanings for self-localization tasks. The proposed method is nonparametric Bayesian spatial concept acquisition method (SpCoA) that integrates the generative model for self-localization and the unsupervised word segmentation in uttered sentences via latent variables related to the spatial concept. We implemented the proposed method SpCoA on SIGVerse, which is a simulation environment, and TurtleBot2, which is a mobile robot in a real environment. Further, we conducted experiments for evaluating the performance of SpCoA. The experimental results showed that SpCoA enabled the robot to acquire the names of places from speech sentences. They also revealed that the robot could effectively utilize the acquired spatial concepts and reduce the uncertainty in self-localization.Comment: This paper was accepted in the IEEE Transactions on Cognitive and Developmental Systems. (04-May-2016

On the composition series of the standard Whittaker (g,K)-modules

For a real reductive linear Lie group G, the space of Whittaker functions is the representation space induced from a non-degenerate unitary character of the Iwasawa nilpotent subgroup. Defined are the standard Whittaker (g,K)-modules, which are K-admissible submodules of the space of Whittaker functions. We first determine the structures of them when the infinitesimal characters characterizing them are generic. As an example of the integral case, we determine the composition series of the standard Whittaker (g,K)-module when G is the group U(n,1) and the infinitesimal character is regular integral.Comment: 22page

Deformation and α\alpha clustering in excited states of 42^{42}Ca

The coexistence of various low-lying deformed states in $^{42}$Ca and $\alpha$--$^{38}$Ar correlations in those deformed states have been investigated using deformed-basis antisymmetrized molecular dynamics. Wave functions of the low-lying states are obtained via parity and angular momentum projections and the generator coordinate method (GCM). Basis wave functions of the GCM calculation are obtained via energy variations with constraints on the quadrupole deformation parameter $\beta$ and the distance between $\alpha$ and $^{38}$Ar clusters. The rotational band built on the $J^\pi = 0_2^+$ (1.84 MeV) state as well as the $J^\pi = 0_3^+$ (3.30 MeV) state are both reproduced. The coexistence of two additional $K^\pi = 0^+$ rotational bands is predicted; one band is shown to be built on the $J^\pi = 0_3^+$ state. Members of the ground-state band and the rotational band built on the $J^\pi = 0_3^+$ state contain $\alpha$--$^{38}$Ar cluster structure components.Comment: 11 pages, 6 figure

A mean value theorem for the square of class number times regulator of quadratic extensions

Let $k$ be a number field. In this paper, we give a formula for the mean value of the square of class numbers times regulators for certain families of quadratic extensions of $k$ characterized by finitely many local conditions. We approach this by using the theory of the zeta function associated with the space of pair of quaternion algebras.Comment: 35 pages, AMS LaTeX; added a reference and rewrote Section