Survival of the black hole's Cauchy horizon under non-compact perturbations

We study numerically the evolution of spactime, and in particular of a spacetime singularity, inside a black hole under a class of perturbations of non-compact support. We use a very simplified toy model of a spherical charged black hole which is perturbed nonlinearly by a self-gravitating, spherical scalar field. The latter grows logarithmically with advanced time along an outgoing characteristic hypersurface. We find that for that class of perturbations a portion of the Cauchy horizon survives as a non-central, null singularity.Comment: 5 pages, 4 figure

A statistical inference method for the stochastic reachability analysis.

The main contribution of this paper is the characterization of reachability problem associated to stochastic hybrid systems in terms of imprecise probabilities. This provides the connection between reachability problem and Bayesian statistics. Using generalised Bayesian statistical inference, a new concept of conditional reach set probabilities is defined. Then possible algorithms to compute the reach set probabilities are derived

Different Approaches on Stochastic Reachability as an Optimal Stopping Problem

Reachability analysis is the core of model checking of time systems. For stochastic hybrid systems, this safety verification method is very little supported mainly because of complexity and difficulty of the associated mathematical problems. In this paper, we develop two main directions of studying stochastic reachability as an optimal stopping problem. The first approach studies the hypotheses for the dynamic programming corresponding with the optimal stopping problem for stochastic hybrid systems. In the second approach, we investigate the reachability problem considering approximations of stochastic hybrid systems. The main difficulty arises when we have to prove the convergence of the value functions of the approximating processes to the value function of the initial process. An original proof is provided

Profiles of Chicano educational opportunity 1950-1980 the significance of teacher expectations

A classified ad was printed in a Southern California newspaper requesting Chicanos who attended high school between 1950 and 1980 to discuss their school experiences. Eight interviews were conducted; one participant was a college graduate, two others were high school graduates, and the others dropped out of high school to work or start a family. The interviews illuminated how the educational system, namely teachers’ expectations, affected the academic aspirations and achievements of the participants. Interview results showed that the lack of culturally affirming relationships with teachers hindered most interviewees’ ability to make connections between hard work in school and future social and economic benefits

Tactons: structured tactile messages for non-visual information display

Tactile displays are now becoming available in a form that can be easily used in a user interface. This paper describes a new form of tactile output. Tactons, or tactile icons, are structured, abstract messages that can be used to communicate messages non-visually. A range of different parameters can be used for Tacton construction including: frequency, amplitude and duration of a tactile pulse, plus other parameters such as rhythm and location. Tactons have the potential to improve interaction in a range of different areas, particularly where the visual display is overloaded, limited in size or not available, such as interfaces for blind people or in mobile and wearable devices. This paper describes Tactons, the parameters used to construct them and some possible ways to design them. Examples of where Tactons might prove useful in user interfaces are given

Sensitivity study of generalised frequency response functions

The dependence and independence of input signal amplitudes for Generalised Frequency Response Functions(GFRF’s) are discussed based on parametric modelling

Tobacco consumption in the home: impact on social relationships and marking territory

In this paper we move beyond viewing the home as a mere context for consumer decision-making to explore consumption practices and socio-spatial relationships within the home in relation to tobacco consumption. Based on focus groups conducted across ten European countries, our findings suggest that smokers view the home as a safe haven where they are sheltered from the outside regulatory environment. However, tension between smokers and nonsmokers demonstrates that consumption practices within the home may become a process of negotiation, resulting in smokers marking territory in efforts to avoid conflict

Domain and user knowledge in a web-based courseware engineering course, knowlegde-based software engineering.

AIMS is a knowledge-based system for learning and teaching support within the context of distance education. It is aimed not only at enhancing learner's conceptual knowledge in a specific subject area but also at providing knowledge verification tools for the teacher. The system can be used to aid learning and teaching in different subject areas and to provide user-oriented support in searching courserelated information, concept teaching and learning, and conceptual and task-oriented domain structuring

Analysis of nonlinear oscillators in the frequency domain using volterra series Part II : identifying and modelling jump Phenomenon

In this the second part of the paper, a common and severe nonlinear phenomenon called jump, a behaviour associated with the Duffing oscillator and the multi-valued properties of the response solution, is investigated. The new frequency domain criterion of establishing the upper limits of the nonlinear oscillators, developed in Part I of this paper, is applied to predict the onset point of the jump, and the Volterra time and frequency domain analysis of this phenomenon are carried out based on graphical and numerical techniques