NUM-Based Rate Allocation for Streaming Traffic via Sequential Convex Programming

In recent years, there has been an increasing demand for ubiquitous streaming like applications in data networks. In this paper, we concentrate on NUM-based rate allocation for streaming applications with the so-called S-curve utility functions. Due to non-concavity of such utility functions, the underlying NUM problem would be non-convex for which dual methods might become quite useless. To tackle the non-convex problem, using elementary techniques we make the utility of the network concave, however this results in reverse-convex constraints which make the problem non-convex. To deal with such a transformed NUM, we leverage Sequential Convex Programming (SCP) approach to approximate the non-convex problem by a series of convex ones. Based on this approach, we propose a distributed rate allocation algorithm and demonstrate that under mild conditions, it converges to a locally optimal solution of the original NUM. Numerical results validate the effectiveness, in terms of tractable convergence of the proposed rate allocation algorithm.Comment: 6 pages, conference submissio

The Development of Conceptual Fluency and Metaphorical Competence in L2 Learners

Conceptual Fluency (CF) and Metaphorical Competence (MC) have piqued the interest of a number of L2 researchers. Leading the front are Danesi (1992; 1995; 2003) and Johnson and Rosano (1993) who contend that metaphorical language cannot afford to be ignored by L2 curricula anymore. Their push is to instill in L2 learners a more functional communicative competence over a traditional formal competence. This article reports on a study carried out to scrutinize the development of CF and MC in Persian students of English. First, a group of language students (95 freshmen, 92 sophomores, 139 juniors, and 90 seniors) were tested to see whether they were conceptually and metaphorically competent, and the results showed they were almost bereft of such a competence, and the analysis of their written discourse uncovered a very low level of metaphorical density. The findings were in line with what Danesi (1992) has averred: L2 learners do not necessarily develop CF and MC after several years of study. Then, the juniors partook in the study for a six-month period in which they were exposed to and taught about the metaphorical language of English. The posttest results were indicative that they had developed their CF and MC to a large extent and that their written discourse was almost as metaphorically dense as that of native speakers. That is, the findings revealed that it is possible to develop CF and MC in a classroom setting. Finally, the data indicated that there is a relationship between CF and MC