RAS-Models: A Building Block for Self-Healing Benchmarks

To evaluate the efficacy of self-healing systems a rigorous, objective, quantitative benchmarking methodology is needed. However, developing such a benchmark is a non-trivial task given the many evaluation issues to be resolved, including but not limited to: quantifying the impacts of faults, analyzing various styles of healing (reactive, preventative, proactive), accounting for partially automated healing and accounting for incomplete/imperfect healing. We posit, however,that it is possible to realize a self-healing benchmark using a collection of analytical techniques and practical tools as building blocks. This paper highlights the flexibility of one analytical tool, the Reliability, Availability and Serviceability (RAS) model, and illustrates its power and relevance to the problem of evaluating self-healing mechanisms/systems, when combined with practical tools for fault-injection

The Role of Reliability, Availability and Serviceability (RAS) Models in the Design and Evaluation of Self-Healing Systems

In an idealized scenario, self-healing systems predict, prevent or diagnose problems and take the appropriate actions to mitigate their impact with minimal human intervention. To determine how close we are to reaching this goal we require analytical techniques and practical approaches that allow us to quantify the effectiveness of a system's remediations mechanisms. In this paper we apply analytical techniques based on Reliability, Availability and Serviceability (RAS) models to evaluate individual remediation mechanisms of select system components and their combined effects on the system. We demonstrate the applicability of RAS-models to the evaluation of self-healing systems by using them to analyze various styles of remediations (reactive, preventative etc.), quantify the impact of imperfect remediations, identify sub-optimal (less effective) remediations and quantify the combined effects of all the activated remediations on the system as a whole

Effect of metabolic and antioxidant supplementation on sperm parameters in oligo-astheno-teratozoospermia, with and without varicocele: a double-blind placebo-controlled study

Since sperm require high energy levels to perform their specialised function, it is vital that essential nutrients are available for spermatozoa when they develop, capacitate and acquire motility. However, they are vulnerable to a lack of energy and excess amounts of reactive oxygen species, which can impair sperm function, lead to immotility, acrosomal reaction impairment, DNA fragmentation and cell death. This monocentric, randomised, double-blind, placebo-controlled trial investigated the effect of 6 months of supplementation with l-carnitine, acetyl-l-carnitine and other micronutrients on sperm quality in 104 subjects with oligo- and/or astheno- and/or teratozoospermia with or without varicocele. In 94 patients who completed the study, sperm concentration was significantly increased in supplemented patients compared to the placebo (p =.0186). Total sperm count also increased significantly (p =.0117) in the supplemented group as compared to the placebo group. Both, progressive and total motility were higher in supplemented patients (p =.0088 and p =.0120, respectively). Although pregnancy rate was not an endpoint of the study, of the 12 pregnancies that occurred during the follow-up, 10 were reported in the supplementation group. In general, all these changes were more evident in varicocele patients. In conclusion, supplementation with metabolic and antioxidant compounds could be efficacious when included in strategies to improve fertility

Multiple copy 2-state discrimination with individual measurements

We address the problem of non-orthogonal two-state discrimination when multiple copies of the unknown state are available. We give the optimal strategy when only fixed individual measurements are allowed and show that its error probability saturates the collective (lower) bound asymptotically. We also give the optimal strategy when adaptivity of individual von Neumann measurements is allowed (which requires classical communication), and show that the corresponding error probability is exactly equal to the collective one for any number of copies. We show that this strategy can be regarded as Bayesian updating.Comment: 5 pages, RevTe

Tripartite entanglement and quantum relative entropy

We establish relations between tripartite pure state entanglement and additivity properties of the bipartite relative entropy of entanglement. Our results pertain to the asymptotic limit of local manipulations on a large number of copies of the state. We show that additivity of the relative entropy would imply that there are at least two inequivalent types of asymptotic tripartite entanglement. The methods used include the application of some useful lemmas that enable us to analytically calculate the relative entropy for some classes of bipartite states.Comment: 7 pages, revtex, no figures. v2: discussion about recent results, 2 refs. added. Published versio

Multiple Corrosion Protection Systems for Reinforced Concrete Bridge Components

the rapid macrocell, Southern Exposure, cracked beam, and linear polarization resistance tests. The systems include bars that are pretreated with zinc chromate to improve the adhesion between the epoxy and the reinforcing steel; two epoxies with improved adhesion to the reinforcing steel; one inorganic corrosion inhibitor, calcium nitrite; two organic corrosion inhibitors; an epoxy-coated bar with a primer containing microencapsulated calcium nitrite; the three epoxy-coated bars with improved adhesion combined with the corrosion inhibitor calcium nitrite; and multiple coated bars with an initial 50-μm (2-mil) coating of 98 percent zinc and 2 percent aluminum followed by a conventional epoxy-coating. The systems are compared with conventional uncoated reinforcement and conventional epoxy-coated reinforcement. The results presented in this report represent the findings obtained during the first half of a 5-year study that includes longer-term ASTM G 109 and field tests. In the short-term tests used to date, the epoxy-coatings evaluated provide superior corrosion protection to the reinforcing steel. The results also indicate that the bars will continue to perform well in the longer term, although the tests do not evaluate the effects of long-term reductions in the bond between the epoxy and the reinforcing steel. The corrosion rate on the exposed regions of damaged epoxy-coated reinforcement is somewhat higher than the average corrosion rate on the surface of uncoated reinforcement subjected to similar exposure conditions. The use of concrete with a reduced water-cement ratio improves the corrosion performance of both conventional and epoxy-coated reinforcement in uncracked concrete but has little effect in cracked concrete. Increased adhesion between the epoxy and reinforcing steel provides no significant improvement in the corrosion resistance of epoxy-coated reinforcement. It appears that corrosion inhibitors in concrete and the primer coating containing microencapsulated calcium nitrite improve the corrosion resistance of the epoxy-coated steel in uncracked concrete, but not in cracked concrete. The zinc coating on the multiple coated bars acts as a sacrificial barrier and provides some corrosion protection to the underlying steel in both uncracked and cracked concrete. The degree of protection, however, cannot be evaluated based on the results available to date

Local distinguishability of quantum states in infinite dimensional systems

We investigate local distinguishability of quantum states by use of the convex analysis about joint numerical range of operators on a Hilbert space. We show that any two orthogonal pure states are distinguishable by local operations and classical communications, even for infinite dimensional systems. An estimate of the local discrimination probability is also given for some family of more than two pure states

Effect of Corrosion Inhibitors on Concrete Pore Solution Composition and Corrosion Resistance

Three commercially available corrosion inhibitors—calcium nitrite, a solution of amines and esters, and an alkenyl-substituted succinic acid salt—are evaluated in conjunction with conventional reinforcement in concrete based on corrosion rate, metal loss, the critical chloride corrosion threshold (CCCT), pore solution analyses, and concrete compressive strength. All three inhibitors increase time to corrosion initiation and decrease corrosion rate, but are less effective in cracked concrete than in uncracked concrete. Of the three inhibitors, the alkenyl-substituted succinic acid salt results in the greatest decrease in corrosion rate, but exhibits the lowest CCCT—below that measured in concrete with no inhibitor. The compressive strengths of concretes containing the amine-ester inhibitor and the alkenyl-substituted succinic acid salt were 15% and 60% lower, espectively, than concrete without an inhibitor. For the latter inhibitor, pore solution analyses indicated elevated sulfate contents at 1 and 7 days, which may explain the low CCCT and strength. Paste containing the amine-ester inhibitor had an elevated sulfate content at 7 days

Effect of Corrosion Inhibitors on Concrete Pore Solution Composition and Corrosion Resistance

Three commercially available corrosion inhibitors—calcium nitrite, a solution of amines and esters, and an alkenyl-substituted succinic acid salt—are evaluated in conjunction with conventional reinforcement in concrete based on corrosion rate, metal loss, the critical chloride corrosion threshold (CCCT), pore solution analyses, and concrete compressive strength. All three inhibitors increase time to corrosion initiation and decrease corrosion rate, but are less effective in cracked concrete than in uncracked concrete. Of the three inhibitors, the alkenyl-substituted succinic acid salt results in the greatest decrease in corrosion rate, but exhibits the lowest CCCT—below that measured in concrete with no inhibitor. The compressive strengths of concretes containing the amine-ester inhibitor and the alkenyl substituted succinic acid salt were 15% and 60% lower, respectively, than concrete without an inhibitor. For the latter inhibitor, pore solution analyses indicated elevated sulfate contents at 1 and 7 days, which may explain the low CCCT and strength. Paste containing the amine-ester inhibitor had an elevated sulfate content at 7 days