20,575 research outputs found
Collecting and Analyzing Failure Data of Bluetooth Personal Area Networks
This work presents a failure data analysis campaign on
Bluetooth Personal Area Networks (PANs) conducted on
two kind of heterogeneous testbeds (working for more than
one year). The obtained results reveal how failures distribution
are characterized and suggest how to improve the
dependability of Bluetooth PANs. Specically, we dene the
failure model and we then identify the most effective recovery
actions and masking strategies that can be adopted for
each failure. We then integrate the discovered recovery actions
and masking strategies in our testbeds, improving the
availability and the reliability of 3.64% (up to 36.6%) and
202% (referred to the Mean Time To Failure), respectively
On the role of pre and post-processing in environmental data mining
The quality of discovered knowledge is highly depending on data quality. Unfortunately real data use to contain noise, uncertainty, errors, redundancies or even irrelevant information. The more complex is the reality to be analyzed, the higher the risk of getting low quality data. Knowledge Discovery from Databases (KDD) offers a global framework to prepare data in the right form to perform correct analyses. On the other hand, the quality of decisions taken upon KDD results, depend not only on the quality of the results themselves, but on the capacity of the system to communicate those results in an understandable form. Environmental systems are particularly complex and environmental users particularly require clarity in their results. In this paper some details about how this can be achieved are provided. The role of the pre and post processing in the whole process of Knowledge Discovery in environmental systems is discussed
A Framework for Robust Assessment of Power Grid Stability and Resiliency
Security assessment of large-scale, strongly nonlinear power grids containing
thousands to millions of interacting components is a computationally expensive
task. Targeting at reducing the computational cost, this paper introduces a
framework for constructing a robust assessment toolbox that can provide
mathematically rigorous certificates for the grids' stability in the presence
of variations in power injections, and for the grids' ability to withstand a
bunch sources of faults. By this toolbox we can "off-line" screen a wide range
of contingencies or power injection profiles, without reassessing the system
stability on a regular basis. In particular, we formulate and solve two novel
robust stability and resiliency assessment problems of power grids subject to
the uncertainty in equilibrium points and uncertainty in fault-on dynamics.
Furthermore, we bring in the quadratic Lyapunov functions approach to transient
stability assessment, offering real-time construction of stability/resiliency
certificates and real-time stability assessment. The effectiveness of the
proposed techniques is numerically illustrated on a number of IEEE test cases
Getting the Haves to Come out Behind: Fixing the Distributive Injustices of American Health Care
Hyman criticizes an article by Havighurst and Richman regarding the distributive injustices of US health care. Hyman also offers a guide for implementing policy reforms based on the analysis by Havighurst and Richman
Getting the Haves to Come out Behind: Fixing the Distributive Injustices of American Health Care
Hyman criticizes an article by Havighurst and Richman regarding the distributive injustices of US health care. Hyman also offers a guide for implementing policy reforms based on the analysis by Havighurst and Richman
Development of intelligent protection and automation control systems using fuzzy logic elements
In this article, the causes of technological disturbances in electrical systems are considered, and several characteristic disadvantages of the protection and automation of elements of electrical systems are highlighted. The tendency to decrease the reliability of relay protection associated with the transition from analog to digital types of protection is substantiated. Based on the studied examples, the use of fuzzy logic in protections, the expediency of using fuzzy logic elements in protection devices, and the automation of electrical systems to identify types of short circuits are justified. This article analyzes the most common damages and presents the results of modeling an electrical system with transformer coupling, where all types of asymmetric short circuits were initiated. The dynamics of changes in the symmetrical components of short-circuit currents of the forward, reverse, and zero sequences are determined. Rules have been created for the identification of asymmetric types of short circuits. An algorithm of protection and automation operation using fuzzy logic elements has been developed. The proposed algorithm of protection and automation will reduce the time to determine the type of damage and trigger protections
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