MACHS: Mitigating the Achilles Heel of the Cloud through High Availability and Performance-aware Solutions

Cloud computing is continuously growing as a business model for hosting information and communication technology applications. However, many concerns arise regarding the quality of service (QoS) offered by the cloud. One major challenge is the high availability (HA) of cloud-based applications. The key to achieving availability requirements is to develop an approach that is immune to cloud failures while minimizing the service level agreement (SLA) violations. To this end, this thesis addresses the HA of cloud-based applications from different perspectives. First, the thesis proposes a component’s HA-ware scheduler (CHASE) to manage the deployments of carrier-grade cloud applications while maximizing their HA and satisfying the QoS requirements. Second, a Stochastic Petri Net (SPN) model is proposed to capture the stochastic characteristics of cloud services and quantify the expected availability offered by an application deployment. The SPN model is then associated with an extensible policy-driven cloud scoring system that integrates other cloud challenges (i.e. green and cost concerns) with HA objectives. The proposed HA-aware solutions are extended to include a live virtual machine migration model that provides a trade-off between the migration time and the downtime while maintaining HA objective. Furthermore, the thesis proposes a generic input template for cloud simulators, GITS, to facilitate the creation of cloud scenarios while ensuring reusability, simplicity, and portability. Finally, an availability-aware CloudSim extension, ACE, is proposed. ACE extends CloudSim simulator with failure injection, computational paths, repair, failover, load balancing, and other availability-based modules

Modeling and Simulation of Task Allocation with Colored Petri Nets

The task allocation problem is a key element in the solution of several applications from different engineering fields. With the explosion of the amount of information produced by the today Internet-connected solutions, scheduling techniques for the allocation of tasks relying on grids, clusters of computers, or in the cloud computing, is at the core of efficient solutions. The task allocation is an important problem within some branch of the computer sciences and operations research, where it is usually modeled as an optimization of a combinatorial problem with the inconvenience of a state explosion problem. This chapter proposes the modeling of the task allocation problem by the use of Colored Petri nets. The proposed methodology allows the construction of compact models for task scheduling problems. Moreover, a simulation process is possible within the constructed model, which allows the study of some performance aspects of the task allocation problem before any implementation stage

OPTIMAL REQUIREMENT DETERMINATION FOR PRICING AVAILABILITY-BASED SUSTAINMENT CONTRACTS

Sustainment constitutes 70% or more of the total life-cycle cost of many safety-, mission- and infrastructure-critical systems. Prediction and control of the life-cycle cost is an essential part of all sustainment contracts. For many types of systems, availability is the most critical factor in determining the total life-cycle cost of the system. To address this, availability-based contracts have been introduced into the governmental and non-governmental acquisitions space (e.g., energy, defense, transportation, and healthcare).However, the development, implementation, and impact of availability requirements within contracts is not well understood. This dissertation develops a decision support model based on contract theory, formal modeling and stochastic optimization for availability-based contract design. By adoption and extension of the “availability payment” concept introduced for civil infrastructure Public-Private Partnerships (PPPs) and pricing for Performance-Based Logistics (PBL) contracts, this dissertation develops requirements that maximize the outcome of contracts for both parties. Under the civil infrastructure “availability payment” PPP, once the asset is available for use, the private sector begins receiving a periodical payment for the contracted number of years based on meeting performance requirements. This approach has been applied to highways, bridges, etc. The challenge is to determine the most effective requirements, metrics and payment model that protects the public interest, (i.e., does not overpay the private sector) but also minimizes that risk that the asset will become unsupported. This dissertation focuses on availability as the key required outcome for mission-critical systems and provides a methodology for finding the optimum requirements and optimum payment parameters, and introduces new metrics into availability-based contract structures. In a product-service oriented environment, formal modeling of contracts (for both the customer and the contractor) will be necessary for pricing, negotiations, and transparency. Conventional methods for simulating a system through its life cycle do not include the effect of the relationship between the contractor and customer. This dissertation integrates engineering models with the incentive structure using a game theoretic simulation, affine controller design and stochastic optimization. The model has been used to explore the optimum availability assessment window (i.e., the length of time over which availability must be assessed) for an availability-based contract

Proceedings Work-In-Progress Session of the 13th Real-Time and Embedded Technology and Applications Symposium

The Work-In-Progress session of the 13th IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS\u2707) presents papers describing contributions both to state of the art and state of the practice in the broad field of real-time and embedded systems. The 17 accepted papers were selected from 19 submissions. This proceedings is also available as Washington University in St. Louis Technical Report WUCSE-2007-17, at http://www.cse.seas.wustl.edu/Research/FileDownload.asp?733. Special thanks go to the General Chairs – Steve Goddard and Steve Liu and Program Chairs - Scott Brandt and Frank Mueller for their support and guidance

Advanced reliability analysis of complex offshore Energy systems subject to condition based maintenance.

As the demand for energy in our world today continues to increase and conventional reserves become less available, energy companies find themselves moving further offshore and into more remote locations for the promise of higher recoverable reserves. This has been accompanied by increased technical, safety and economic risks as the unpredictable and dynamic conditions provide a challenge for the reliable and safe operation of both oil and gas (O&G) and offshore wind energy assets. Condition-based maintenance (CBM) is growing in popularity and application in offshore energy production, and its integration into the reliability analysis process allows for more accurate representation of system performance. Advanced reliability analysis while taking condition-based maintenance (CBM) into account can be employed by researchers and practitioners to develop a better understanding of complex system behaviour in order to improve reliability allocation as well as operation and maintenance (O&M). The aim of this study is therefore to develop models for reliability analysis which take into account dynamic offshore conditions as well as condition-based maintenance (CBM) for improved reliability and O&M. To achieve this aim, models based on the stochastic petri net (SPN) and dynamic Bayesian network (DBN) techniques are developed to analyse the reliability and optimise the O&M of complex offshore energy assets. These models are built to take into account the non-binary nature, maintenance regime and repairability of most offshore energy systems. The models are then tested using benchmark case studies such as a subsea blowout preventer, a floating offshore wind turbine (FOWT), an offshore wind turbine (OWT) gearbox and an OWT monopile. Results from these analyses reveal that the incorporation of degradation and CBM can indeed be done and significantly influence the reliability analysis and O&M planning of offshore energy assets.Shafiee, Mahmood (Associate)PhD in Energy and Powe

Vulnérabilité, interdépendance et analyse des risques des postes sources et des modes d’exploitation décentralisés des réseaux électriques

In view of the increasing use of Information and Communication Technol-ogies in power systems, it is essential to study the interdependencies between these coupled heterogeneous systems. This thesis focuses on the modeling of multi- infrastructure systems. This includes interdependencies and the three major failures families: common mode, escalat-ing and cascading. It is indeed necessary to identify the weaknesses that can trigger one or multiple failure(s) and cascade through these interdependent infrastructures, causing unex-pected and increasingly more serious failures to other infrastructures. In this context, different approaches, based on the theory of Complex Networks, are developed to identify the most critical components in the coupled heterogeneous system. One of the major scientific barriers addressed in this thesis is the development of a unified mathematical model to represent the behavior.Au vu de l’utilisation croissante des technologies de l’information et de la communication dans les réseaux électriques, il est indispensable d’étudier l’étroite liaison entre ces infrastructures et d’avoir une vision intégrée du système couplé. Cette thèse porte ainsi sur la modélisation des systèmes multi-infrastructures. Cela inclut les interdépendances et les trajectoires de défaillances de type modes communs, aggravations et cascades. Il est en effet nécessaire d’identifier les points de faiblesse qui peuvent déclencher une ou de multiples défaillance(s), se succéder en cascade au travers de ces infrastructures liées et ainsi entrainer des défaillances inattendues et de plus en plus graves dans des autres infrastructures. Dans cette optique, différents modèles basés sur la théorie des Réseaux Complexes sont développés afin d’identifier les composants les plus importantes, et pourtant critiques, dans le système interconnecté. Un des principaux verrous scientifiques levé dans cette thèse est relatif au développement d'un modèle mathématique « unifié » afin de représenter les comportements des multiples infrastructures non-homogènes qui ont des interdépendances asymétriques

Production Scheduling

Generally speaking, scheduling is the procedure of mapping a set of tasks or jobs (studied objects) to a set of target resources efficiently. More specifically, as a part of a larger planning and scheduling process, production scheduling is essential for the proper functioning of a manufacturing enterprise. This book presents ten chapters divided into five sections. Section 1 discusses rescheduling strategies, policies, and methods for production scheduling. Section 2 presents two chapters about flow shop scheduling. Section 3 describes heuristic and metaheuristic methods for treating the scheduling problem in an efficient manner. In addition, two test cases are presented in Section 4. The first uses simulation, while the second shows a real implementation of a production scheduling system. Finally, Section 5 presents some modeling strategies for building production scheduling systems. This book will be of interest to those working in the decision-making branches of production, in various operational research areas, as well as computational methods design. People from a diverse background ranging from academia and research to those working in industry, can take advantage of this volume

Application of Optimization in Production, Logistics, Inventory, Supply Chain Management and Block Chain

The evolution of industrial development since the 18th century is now experiencing the fourth industrial revolution. The effect of the development has propagated into almost every sector of the industry. From inventory to the circular economy, the effectiveness of technology has been fruitful for industry. The recent trends in research, with new ideas and methodologies, are included in this book. Several new ideas and business strategies are developed in the area of the supply chain management, logistics, optimization, and forecasting for the improvement of the economy of the society and the environment. The proposed technologies and ideas are either novel or help modify several other new ideas. Different real life problems with different dimensions are discussed in the book so that readers may connect with the recent issues in society and industry. The collection of the articles provides a glimpse into the new research trends in technology, business, and the environment