Spectral analysis of linear time series in moderately high dimensions

This article is concerned with the spectral behavior of $p$-dimensional linear processes in the moderately high-dimensional case when both dimensionality $p$ and sample size $n$ tend to infinity so that $p/n\to0$. It is shown that, under an appropriate set of assumptions, the empirical spectral distributions of the renormalized and symmetrized sample autocovariance matrices converge almost surely to a nonrandom limit distribution supported on the real line. The key assumption is that the linear process is driven by a sequence of $p$-dimensional real or complex random vectors with i.i.d. entries possessing zero mean, unit variance and finite fourth moments, and that the $p\times p$ linear process coefficient matrices are Hermitian and simultaneously diagonalizable. Several relaxations of these assumptions are discussed. The results put forth in this paper can help facilitate inference on model parameters, model diagnostics and prediction of future values of the linear process

Authorization algorithms for permission-role assignments

Permission-role assignments (PRA) is one important process in Role-based access control (RBAC) which has been proven to be a flexible and useful access model for information sharing in distributed collaborative environments. However, problems may arise during the procedures of PRA. Conflicting permissions may assign to one role, and as a result, the role with the permissions can derive unexpected access capabilities. This paper aims to analyze the problems during the procedures of permission-role assignments in distributed collaborative environments and to develop authorization allocation algorithms to address the problems within permission-role assignments. The algorithms are extended to the case of PRA with the mobility of permission-role relationship. Finally, comparisons with other related work are discussed to demonstrate the effective work of the paper

A Review of Theories in L2 Socialization and Cognitive Approaches to Second Language Acquisition

In the past 20 years, there is a shifting trend in the second language acquisition (SLA) field departing from the traditional “logical science” (Zuengler & Miller, 2006) to a context-oriented perspective for its robust power in exploring social factors beyond individual internal cognition in L2 processing research. While context-oriented researchers claim the formal linguistic-focused research decontextualizes L2 learning from its environment and thus is problematic to comprehensively explain the L2 acquisition process, some scholars taking formal linguistic perspectives resist such critique and contend that social conditions are neither sufficient nor “necessary for scientific discovery” (Zuengler & Miller, 2006, p. 15). Within this paper, I will interrogate what differentiates the cognitive paradigm from L2 socialization paradigm in terms of second language acquisition