Application of plants extracts as green corrosion inhibitors for steel in concrete - a review

High requirements in protection of steel reinforcing bar (steel rebar) from corrosion are necessary since there are multi in�teraction of corrosive chemicals which cause early damage of concrete buildings. Corrosion of steel in concrete can destroy the concretes and reduce concrete strength. To protect rebar from corrosion, application of corrosion inhibitor is believed to have higher performance compared to other protection systems. To date, organic inhibitors have promising methods in steel rebar protection as they are environment-friendly, compatible with concrete, cost effective and applicable in any various concrete conditions. Thus, demands in using these in�hibitors tend to increase significantly. This paper reviews the applications of green corrosion inhibitor specifically high�lighted in protecting mechanisms, typical plants extracted, performance in corrosion protection, and classification of green corrosion inhibitors. The corrosion resistances of car�bon steels in concrete protected by green inhibitors are in fo�cus. As summary, it can be confidently notified that green cor�rosion inhibitors for steel in concrete will have a prospect to be used as corrosion prevention in the future with further im�provements

Applying Formal Methods to Networking: Theory, Techniques and Applications

Despite its great importance, modern network infrastructure is remarkable for the lack of rigor in its engineering. The Internet which began as a research experiment was never designed to handle the users and applications it hosts today. The lack of formalization of the Internet architecture meant limited abstractions and modularity, especially for the control and management planes, thus requiring for every new need a new protocol built from scratch. This led to an unwieldy ossified Internet architecture resistant to any attempts at formal verification, and an Internet culture where expediency and pragmatism are favored over formal correctness. Fortunately, recent work in the space of clean slate Internet design---especially, the software defined networking (SDN) paradigm---offers the Internet community another chance to develop the right kind of architecture and abstractions. This has also led to a great resurgence in interest of applying formal methods to specification, verification, and synthesis of networking protocols and applications. In this paper, we present a self-contained tutorial of the formidable amount of work that has been done in formal methods, and present a survey of its applications to networking.Comment: 30 pages, submitted to IEEE Communications Surveys and Tutorial

Synthesis of Probabilistic Models for Quality-of-Service Software Engineering

An increasingly used method for the engineering of software systems with strict quality-of-service (QoS) requirements involves the synthesis and verification of probabilistic models for many alternative architectures and instantiations of system parameters. Using manual trial-and-error or simple heuristics for this task often produces suboptimal models, while the exhaustive synthesis of all possible models is typically intractable. The EvoChecker search-based software engineering approach presented in our paper addresses these limitations by employing evolutionary algorithms to automate the model synthesis process and to significantly improve its outcome. EvoChecker can be used to synthesise the Pareto-optimal set of probabilistic models associated with the QoS requirements of a system under design, and to support the selection of a suitable system architecture and configuration. EvoChecker can also be used at runtime, to drive the efficient reconfiguration of a self-adaptive software system. We evaluate EvoChecker on several variants of three systems from different application domains, and show its effectiveness and applicability

Adaptive Traffic Control System: Design and Simulation

Traditional traffic control infrastructures have not changed much in the last several decades, while the volume of traffic has increased disproportionably to infrastructure improvement. A solution to mobility cannot be addressed by simply improving the technology of a single vehicle any further. A solution is to enable people to reach their destinations safely and in optimal time, given the topology of road networks. This thesis offers such a solution based on an adaptive traffic control algorithm which takes the road network topology and dynamically varying traffic streams as input, and guarantees dependable and optimal mobility for vehicles. The algorithm calculates dependable passages for vehicles to cross road intersections, and enables point-to-point travel by minimizing travel time and maximizing fuel consumption. The adaptive algorithm is embedded in the Arbiter, managed by an Intersection Manager at every road intersection. A distributed traffic management architecture, consisting of a hierarchy of road managers, is proposed in the thesis. Extensions to the adaptive algorithm and the architecture are given. The extended algorithm will efficiently function under exceptional situations, such as bad weather, road repairs, and emergency vehicle mobility. The extended architecture is expected to have autonomic computing properties, such as self-healing, self-recovery, and self-protection, and Cyber-physical system properties, such as tightly-coupled feed-back loops with all entities in its environment. A simulator has been implemented, and simulated results reveal that the adaptive algorithm is far superior in performance to fixed-time control systems

A Categorical Approach to Verifying Consistency in Concurrent Systems

A concurrent system involves several executing components. Such a system usually allows to carry out multiple tasks at the same time, which can speed up the computational work of software substantially. The recent research findings demonstrate that process-oriented programming languages provide a suitable means for developing concurrent systems. However, design and implementation are at different levels of abstraction in software development process. It is challenging to incorporate knowledge and experience to control the consistency between these phases in developing concurrent systems. The potential inconsistencies arising would introduce errors to the production of concurrent systems, which would prove fatal to the systems in areas with zero tolerance for failure. To tackle such a challenge, the goal of this research is to propose an innovative categorical framework for designing, implementing and verifying the consistency of communications. This framework is inspired by Hoare's vision of category theory and obtained research results towards validating the vision. In this framework, Communicating Sequential Processes(CSP) and Erasmus are used for design and implementation. In addition, abstract interpretation is employed to extract process communications from implementation. Furthermore, several novel rules to analyze semantics of abstraction of implementation are proposed for Erasmus. Finally, category theory is utilized as an innovative means to model and verify consistency of process communications. The framework is illustrated by using several running examples

Simulation product fidelity: a qualitative & quantitative system engineering approach

La modélisation informatique et la simulation sont des activités de plus en plus répandues lors de la conception de systèmes complexes et critiques tels que ceux embarqués dans les avions. Une proposition pour la conception et réalisation d'abstractions compatibles avec les objectifs de simulation est présentée basés sur la théorie de l'informatique, le contrôle et le système des concepts d'ingénierie. Il adresse deux problèmes fondamentaux de fidélité dans la simulation, c'est-à-dire, pour une spécification du système et quelques propriétés d'intérêt, comment extraire des abstractions pour définir une architecture de produit de simulation et jusqu'où quel point le comportement du modèle de simulation représente la spécification du système. Une notion générale de cette fidélité de la simulation, tant architecturale et comportementale, est expliquée dans les notions du cadre expérimental et discuté dans le contexte des abstractions de modélisation et des relations d'inclusion. Une approche semi-formelle basée sur l'ontologie pour construire et définir l'architecture de produit de simulation est proposée et démontrée sur une étude d'échelle industrielle. Une approche formelle basée sur le jeu théorique et méthode formelle est proposée pour différentes classes de modèles des systèmes et des simulations avec un développement d'outils de prototype et cas des études. Les problèmes dans la recherche et implémentation de ce cadre de fidélité sont discutées particulièrement dans un contexte industriel.In using Modeling and Simulation for the system Verification & Validation activities, often the difficulty is finding and implementing consistent abstractions to model the system being simulated with respect to the simulation requirements. A proposition for the unified design and implementation of modeling abstractions consistent with the simulation objectives based on the computer science, control and system engineering concepts is presented. It addresses two fundamental problems of fidelity in simulation, namely, for a given system specification and some properties of interest, how to extract modeling abstractions to define a simulation product architecture and how far does the behaviour of the simulation model represents the system specification. A general notion of this simulation fidelity, both architectural and behavioural, in system verification and validation is explained in the established notions of the experimental frame and discussed in the context of modeling abstractions and inclusion relations. A semi-formal ontology based domain model approach to build and define the simulation product architecture is proposed with a real industrial scale study. A formal approach based on game theoretic quantitative system refinement notions is proposed for different class of system and simulation models with a prototype tool development and case studies. Challenges in research and implementation of this formal and semi-formal fidelity framework especially in an industrial context are discussed