Modified gravity inside astrophysical bodies

Many theories of modified gravity, including the well studied Horndeski models, are characterized by a screening mechanism that ensures that standard gravity is recovered near astrophysical bodies. In a recently introduced class of gravitational theories that goes beyond Horndeski, it has been found that new derivative interactions lead to a partial breaking of the Vainshtein screening mechanism inside any gravitational source, although not outside. We study the impact of this new type of deviation from standard gravity on the density profile of a spherically symmetric matter distribution, in the nonrelativistic limit. For simplicity, we consider a polytropic equation of state and derive the modifications to the standard Lane-Emden equations. We also show the existence of a universal upper bound on the amplitude of this type of modified gravity, independently of the details of the equation of state.Comment: 11 pages, 6 figure

Pressure-Induced Restoration of the Reversed Crystal-Field Splitting in α\alpha-Sr2_2CrO4_4

Motivated by an experimental finding that the successive phase transitions in $\alpha$-Sr$_2$CrO$_4$ observed at ambient pressure ceases to exist under high pressures, we carry out the density-functional-theory-based electronic structure calculations and demonstrate that the reversal of the crystal-field splitting reported previously is restored under high pressures, so that the orbital degrees of freedom disappears, resulting in the single phase transition that divides the system into high-temperature Mott insulating and low-temperature antiferromagnetic insulating phases.Comment: 5 pages, 1 figure, to appear in JPS Conf. Proc. (Proceedings for SCES2019

A DISTANCE LEARNING SYSTEM WITH CUSTOMIZABLE SCREEN LAYOUTS FOR MULTIPLE LEARNING SITUATIONS

In this paper, we propose a new distance learning system that can adapt to various styles of learning activity. We assume that the system is used in distance classes with multiple live-streaming videos. Our system has functions to change the screen layout to best suit for the current learning situation for each of the participants in a class. The system also has a function to efficiently monitor the behavior of many students at a time. These functions enable us to adapt various learning activities in distance learning classes. We implemented a prototype of the proposed system and evaluated it in experimental classes. We confirmed that our system improved the activities in the experimental classes

MMSE Analysis for Generated Robot Motion Language with ALBERT

The 11th International Symposium on Adaptive Motion of Animals and Machines. Kobe University, Japan. 2023-06-06/09. Adaptive Motion of Animals and Machines Organizing Committee.Poster Session P2

DroidTrack: Tracking Information Diffusion and Preventing Information Leakage on Android

Abstract. An app in Android can collaborate with other apps and control personal information by using the Intent or user's allowing of permission. However, users cannot detect when they communicate. Therefore, users might not be aware information leakage if app is malware. This paper proposes DroidTrack, a method for tracking the diffusion of personal information and preventing its leakage on an Android device. DroidTrack alerts the user of the possibility of information leakage when an app uses APIs to communicate with outside. These alerts are triggered only if the app has already called APIs to collect personal information. Users are given the option to refuse the execution of the API if it is not appropriate. Further, by illustrating how their personal data is diffused, users can have the necessary information to help them decide whether the API use is appropriate

The Role of Nanostructural Chemistry in the Design of Solid Catalysts

We report here the results of molecular dynamics and quantum chemical calculations on porous catalysts and supported metal catalysts to bring out the catalytic role played by nanostructures. We present three case studies where the computer simulation techniques have revealed the important structural aspects involved in the catalyst design. The role of exchanged metal cations in zeolite A for the molecular sieving of nitrogen and oxygen, controlled pore opening of hydrated VPI-5 by careful removal of water and the behavior of palladium metal particles supported over MgO are explained

Performance Evaluation of Several Implicit FDTD Methods for Optical Waveguide Analyses

he performance of the recently developed implicit finite-difference time-domain methods (FDTDs) is compared with that of the traditional explicit FDTD. For the implicit methods, the alternating-direction implicit (ADI) FDTD and the envelope ADI-FDTD are investigated. In addition, the locally one-dimensional (LOD) scheme is newly introduced into implicit FDTDs, i.e., LOD-and envelope LOD-FDTDs are developed for simple implementation of the algorithm and reduced CPU time. Numerical dispersion analysis is performed, demonstrating the improved dispersion properties of the envelope FDTD. Numerical results of a waveguide grating reveal that the wavelength responses obtained from the ADI/LOD-FDTD gradually shift toward a longer wavelength as the time step (△.t) is increased. For the envelope ADI/LOD-FDTD with △.t =8△.tCFL ,inwhich　△.tCFL is determined by the stability criterion, the responses are in good agreement with the response of the explicit FDTD, showing the comparable CPU time to that of the explicit FDTD. Further calculations of a waveguide with high-reflection coatings reveal that the CPU time of the envelope LOD-FDTD with △.t = 32△.tCFL is reduced to 25% of that of the explicit FDTD