The critical infrastructures of a nation including the power grid and the communication network are highly interdependent. Recognizing the need for a deeper understanding of the interdependency in a multi-layered netw...
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The critical infrastructures of a nation including the power grid and the communication network are highly interdependent. Recognizing the need for a deeper understanding of the interdependency in a multi-layered network, significant efforts have been made by the research community in the last few years to achieve this goal. Accordingly a number of models have been proposed and analyzed. Unfortunately, most of the models are over simplified and, as such, they fail to capture the complex interdependency that exists between entities of the power grid and the communication networks involving a combination of conjunctive and disjunctive relations. To overcome the limitations of existing models, we propose a new model that is able to capture such complex interdependency relations. Utilizing this model, we provide techniques to identify the K most “vulnerable” nodes of an interdependent network. We show that the problem can be solved in polynomial time in some special cases, whereas for some others, the problem is NP-complete. We establish that this problem is equivalent to computation of a fixed point of a multilayered network system and we provide a technique for its computation utilizing Integer Linear programming. Finally, we evaluate the efficacy of our technique using real data collected from the power grid and the communication network that span the Maricopa County of Arizona.
Advances in technology have resulted in Internet-scale deployment of storage systems such as peer-to-peer storage and cloud storage, where data is distributed over multiple storage nodes in a networked environment. In...
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Advances in technology have resulted in Internet-scale deployment of storage systems such as peer-to-peer storage and cloud storage, where data is distributed over multiple storage nodes in a networked environment. In these environments the storage nodes are often commodity machines and are susceptible to failure. The notion of fault domain, introduced by Microsoft Azure, captures the fault-tolerance aspects of a data center. A fault domain is defined as a set of servers all of which become inaccessible when a single fault (such as the failure of a switch or a router) occurs in the data center. As such a fault domain can be viewed as a spatially correlated or region based failure. In order to enhance reliability through redundancy, maximum distance separable (MDS) codes such as Reed-Solomon codes and (N, K) codings are utilized. In this paper we present analytical results demonstrating that the choice of the coding parameters N and K may have significant impact on storage that will be necessary to achieve reliability. We present a polynomial time algorithm for optimal storage allocation in a mesh network and we conduct extensive experimentation to evaluate the impact of the coding parameters N and K on the storage requirement to provide all region fault tolerance with varying size of the mesh and the fault region.
Studies on communication network robustness, though extensive, have primarily focused on standalone networks. However, real world communication networks do not operate in isolation, but instead are part of complex int...
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ISBN:
(纸本)9781479967711
Studies on communication network robustness, though extensive, have primarily focused on standalone networks. However, real world communication networks do not operate in isolation, but instead are part of complex interdependent ecosystems that function together as a comprehensive symbiotic unit. For instance, communication networks of today are highly dependent on the power infrastructure and hence, any efforts to improve the robustness of communication networks must necessarily take into account the vulnerabilities of the power infrastructure and their shared interdependencies. For example, event-induced failures (failures caused by natural disasters or terrorist attacks), on any of these two infrastructures can trigger further failures (triggered failures) into the system through a cascading process due to the interdependencies between the networks. In such an interdependent system where an event induced failure can cascade and result in a much larger combined (event-induced plus triggered) failure, it may be imperative to identify the original event-induced failure for the purpose of post fault diagnostics, or for pre-cascade network strengthening. This ascertainment of event-induced original failure, or the Root Cause of Failure, from combined failures in interdependent Power-Communication networks is the main focus of this paper. We model interdependencies between the two infrastructures using the recently proposed Implicative Interdependency Model. We introduce the Root Cause of Failure problem, and prove it to be NP-Complete. We also provide optimal solutions using ILP, and provide an O(ln(n)) approximation algorithm. Finally, we validate our analytical results through experiments in the power communication network of Maricopa County, Arizona.
The rapid change of trading values from tangible assets to Intelectual Property has put both businesses and academia in a race to acquire and protect the rights to exploit such property. This is mainly accomplished in...
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The rapid change of trading values from tangible assets to Intelectual Property has put both businesses and academia in a race to acquire and protect the rights to exploit such property. This is mainly accomplished in the form of patent issuing by the governments, being time consuming and complicated due to the vast amount of documents that need to be analyzed in order to assert the novelty or validity of a patent application. Patent information retrieval research is thus growing quickly to support document analysis across multiple domains and information systems. One of the big challenges in patent analysis is the identification of the elements of innovation (concepts, processes, materials) and the relations between them, in the patent text. This paper presents a method for extracting semantic information from patent claims by using semantic annotations on phrasal structures, abstracting domain ontology information and outputting ontology-friendly structures to achieve generalization. An extraction system built upon the method is briefly evaluated on a document sample from INPI, the Brazilian patent office, a challenging information source.
The essence of the software ecosystem concept encourages external developers to interact with a software platform, enabling them to contribute or evolve such platform. Trying to expand a product into a platform on whi...
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The treatment of economic and social issues in Software engineering was pointed out as a challenge in the coming years. Organizations have opened up their platforms and assets to others, including partners and third-p...
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The treatment of economic and social issues in Software engineering was pointed out as a challenge for the next years. Companies and organizations have directly (or not) opened up their software platforms and assets t...
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The treatment of economic and social issues in Software engineering was pointed out as a challenge for the next years. Companies and organizations have directly (or not) opened up their software platforms and assets to others, including partners and third-party developers around the world, generating software ecosystems (SECOs). This changes the traditional software industry because it requires mature research in software requirements and architecture in an environment where business models and socio-technical networks can impact the management of the platforms' needs and demands overtime. However, one strong inhibitor is the complexity in defining and modeling SECOs elements to improve their comprehension and analysis and their impacts on requirements engineering. So, this paper introduces an approach to support SECO definition and modeling based on the SECOs domain. The goal consists in dealing with the stakeholders' value proposition and realization in SECOs, as well as treating nontechnical issues in components and social repositories.
Application code and processor parallelization, together with instruction set customization, are the most common and effective ways to enhance the performance and efficiency of application-specific processors (ASIPs)....
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The treatment of economic and social issues in Software engineering was pointed out as a challenge in the coming years. Organizations have opened up their platforms and assets to others, including partners and third-p...
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The treatment of economic and social issues in Software engineering was pointed out as a challenge in the coming years. Organizations have opened up their platforms and assets to others, including partners and third-party developers around the world, generating software ecosystems (SECOs). SECOs research can contribute to minimize nontechnical barriers of software reuse in industry because it explores potential relations among companies and stakeholders. However, an inhibitor is the complexity in defining value for reusable assets. This paper presents an extension of the Brechó-EcoSys environment to support components negotiations in reuse repositories. The focus is on complementing the stakeholders' value proposition and realization, as well as incorporating a nontechnical mechanism in components repositories.
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