On \u3cem\u3ek\u3c/em\u3e-minimum and \u3cem\u3em\u3c/em\u3e-minimum Edge-Magic Injections of Graphs

An edge-magic total labelling (EMTL) of a graph G with n vertices and e edges is an injection λ:V(G) ∪ E(G)→[n+e], where, for every edge uv ∈ E(G), we have wtλ(uv)=kλ, the magic sum of λ. An edge-magic injection (EMI) μ of G is an injection μ : V(G) ∪ E(G) → N with magic sum kμ and largest label mμ. For a graph G we define and study the two parameters κ(G): the smallest kμ amongst all EMI’s μ of G, and m(G): the smallest mμ amongst all EMI’s μ of G. We find κ(G) for G ∈ G for many classes of graphs G. We present algorithms which compute the parameters κ(G) and m(G). These algorithms use a G-sequence: a sequence of integers on the vertices of G whose sum on edges is distinct. We find these parameters for all G with up to 7 vertices. We introduce the concept of a double-witness: an EMI μ of G for which both kμ=κ(G) and mμ=m(G) ; and present an algorithm to find all double-witnesses for G. The deficiency of G, def(G), is m(G)−n−e. Two new graphs on 6 vertices with def(G)=1 are presented. A previously studied parameter of G is κEMTL(G), the magic strength of G: the smallest kλ amongst all EMTL’s λ of G. We relate κ(G) to κEMTL(G) for various G, and find a class of graphs B for which κEMTL(G)−κ(G) is a constant multiple of n−4 for G ∈B. We specialise to G=Kn, and find both κ(Kn) and m(Kn) for all n≤11. We relate κ(Kn) and m(Kn) to known functions of n, and give lower bounds for κ(Kn) and m(Kn)

Virtual Machine Support for Many-Core Architectures: Decoupling Abstract from Concrete Concurrency Models

The upcoming many-core architectures require software developers to exploit concurrency to utilize available computational power. Today's high-level language virtual machines (VMs), which are a cornerstone of software development, do not provide sufficient abstraction for concurrency concepts. We analyze concrete and abstract concurrency models and identify the challenges they impose for VMs. To provide sufficient concurrency support in VMs, we propose to integrate concurrency operations into VM instruction sets. Since there will always be VMs optimized for special purposes, our goal is to develop a methodology to design instruction sets with concurrency support. Therefore, we also propose a list of trade-offs that have to be investigated to advise the design of such instruction sets. As a first experiment, we implemented one instruction set extension for shared memory and one for non-shared memory concurrency. From our experimental results, we derived a list of requirements for a full-grown experimental environment for further research

Early and Prolonged Antiretroviral Therapy Is Associated with an HIV-1-Specific T-Cell Profile Comparable to That of Long-Term Non-Progressors

Background: Intervention with antiretroviral treatment (ART) and control of viral replication at the time of HIV-1 seroconversion may curtail cumulative immunological damage. We have therefore hypothesized that ART maintenance over a very prolonged period in HIV-1 seroconverters could induce an immuno-virological status similar to that of HIV-1 long-term non-progressors (LTNPs).Methodology/Principal Findings: We have investigated a cohort of 20 HIV-1 seroconverters on long-term ART (LTTS) and compared it to one of 15 LTNPs. Residual viral replication and reservoirs in peripheral blood, as measured by cell-associated HIV-1 RNA and DNA, respectively, were demonstrated to be similarly low in both cohorts. These two virologically matched cohorts were then comprehensively analysed by polychromatic flow cytometry for HIV-1-specific CD4(+) and CD8(+) T-cell functional profile in terms of cytokine production and cytotoxic capacity using IFN-gamma, IL-2, TNF-alpha production and perforin expression, respectively. Comparable levels of highly polyfunctional HIV-1-specific CD4(+) and CD8(+) T-cells were found in LTTS and LTNPs, with low perforin expression on HIV-1-specific CD8+ T-cells, consistent with a polyfunctional/non-cytotoxic profile in a context of low viral burden.Conclusions: Our results indicate that prolonged ART initiated at the time of HIV-1 seroconversion is associated with immuno-virological features which resemble those of LTNPs, strengthening the recent emphasis on the positive impact of early treatment initiation and paving the way for further interventions to promote virological control after treatment interruption

A new exercise in concurrency

This article presents an exercise to be assigned whenever undergraduates are introduced to the concepts of concurrency and semaphores. It also presents several possible strategies to solve said exercise along with a "coded " solution

Rating/Ranking Systems, Post-Season Bowl Games, and "The Spread"

A previous article (Trono, 2005) documented how two different rating systems "outperformed" the Las Vegas betting line on NCAA bowl games when they individually disagreed with the line on which team should be favored. This article addresses several shortcomings in one of the two aforementioned systems, extends the analysis in a few new directions for both systems, adds the five most recent years of bowl games to this investigation, and includes one more recently published ranking system in this extensive study that goes back to 1983.

An Effective Nonlinear Rewards-Based Ranking System

This article describes a new strategy for objectively quantifying the performance exhibited by each and every team as derived from that years games. When applied to the last sixteen seasons of division I-A college football, one can readily observe a strong correlation between the final rankings computed using this new strategy and the combined average ranking of the weekly polls administered by the Associated Press (AP) and USA Today (since 1991, and by the United Press International UPI before then). The nearly identical ordering of the top teams in these two rankings after all the post season bowl games have concluded, and the similarity of these rankings before the bowl games were played the past eight seasons, i.e. the "BCS years", are submitted here as evidence for the validity of this strategy.