Search results for "Reliability theory"
showing 10 items of 11 documents
Generalized Entropies, Variance and Applications
2020
The generalized cumulative residual entropy is a recently defined dispersion measure. In this paper, we obtain some further results for such a measure, in relation to the generalized cumulative residual entropy and the variance of random lifetimes. We show that it has an intimate connection with the non-homogeneous Poisson process. We also get new expressions, bounds and stochastic comparisons involving such measures. Moreover, the dynamic version of the mentioned notions is studied through the residual lifetimes and suitable aging notions. In this framework we achieve some findings of interest in reliability theory, such as a characterization for the exponential distribution, various resul…
Dependability-Based Reliability Analysis in URC Networks: Availability in the Space Domain
2019
Ultra-reliable low latency communication (URLLC), which refers to achieving almost 100% reliability at a certain (satisfactory) level of services and stringent latency, is one of the key requirements for 5G networks. However, most prior studies on reliable communication did not address space domain analysis. Neither were they pursued from a dependability perspective. This paper addresses the ultra-reliable communication (URC) aspect of URLLC and aims at advocating the concept of URC from a dependability perspective in the space domain. We perform in-depth analysis on URC considering both the spatial characteristics of cell deployment and user distributions, as well as service requirements. …
System Times and Channel Availability for Secondary Transmissions in CRNs: A Dependability Theory based Analysis
2017
[EN] Reliability is of fundamental importance for the performance of secondary networks in cognitive radio networks (CRNs). To date, most studies have focused on predicting reliability parameters based on prior statistics of traffic patterns from user behavior. In this paper, we define a few reliability metrics for channel access in multichannel CRNs that are analogous to the concepts of reliability and availability in classical dependability theory. Continuous-time Markov chains are employed to model channel available and unavailable time intervals based on channel occupancy status. The impact on user access opportunities based on channel availability is investigated by analyzing the stead…
Multi-State System in human reliability analysis
2009
Application of mathematical model of Multi-State System for human reliability analysis is considered in the paper. This paper describes new method for estimation of changes of more than one component states and they influence to Multi-State System reliability by Dynamic Reliability Indices. The Multi-State System failure is considered depending on decrease of some system component efficiency and the Multi-State System repair is declared depending on replacement of some failed components. The mathematical approach of Logical Differential Calculus is used for analysis of the Multi-State System reliability change that is caused by modifications of some system components states.
Per-user availability for ultra-reliable communication in 5G: Concept and analysis
2018
Emerging 5G mobile networks envisage ultra-reliable communication (URC) as one of the major requirements for anytime anywhere communication. Although URC has recently attracted a lot of attention in the research community, existing work seems to rely on approaching reliability merely from a time domain perspective. However, both time and space domain parameters affect reliability and need to be investigated. This paper introduces a dependability theory based definition for per-user availability targeted at 5G networks. The advocated definition promotes both space and time domain components for URC provisioning. Furthermore, we perform reliability and availability analysis and simulations co…
On Distinguishing between Reliable and Unreliable Sensors Without a Knowledge of the Ground Truth
2015
In many applications, data from different sensors are aggregated in order to obtain more reliable information about the process that the sensors are monitoring. However, the quality of the aggregated information is intricately dependent on the reliability of the individual sensors. In fact, unreliable sensors will tend to report erroneous values of the ground truth, and thus degrade the quality of the fused information. Finding strategies to identify unreliable sensors can assist in having a counter-effect on their respective detrimental influences on the fusion process, and this has has been a focal concern in the literature. The purpose of this paper is to propose a solution to an extreme…
On Solving the Problem of Identifying Unreliable Sensors Without a Knowledge of the Ground Truth: The Case of Stochastic Environments.
2017
The purpose of this paper is to propose a solution to an extremely pertinent problem, namely, that of identifying unreliable sensors (in a domain of reliable and unreliable ones) without any knowledge of the ground truth. This fascinating paradox can be formulated in simple terms as trying to identify stochastic liars without any additional information about the truth. Though apparently impossible, we will show that it is feasible to solve the problem, a claim that is counterintuitive in and of itself. One aspect of our contribution is to show how redundancy can be introduced, and how it can be effectively utilized in resolving this paradox. Legacy work and the reported literature (for exam…
Unbiased Simultaneous Prediction Limits on Observations in Future Samples
2013
This paper provides procedures for constructing unbiased simultaneous prediction limits on the observations or functions of observations of all of k future samples using the results of a previous sample from the same underlying distribution belonging to invariant family. The results have direct application in reliability theory, where the time until the first failure in a group of several items in service provides a measure of assurance regarding the operation of the items. The simultaneous prediction limits are required as specifications on future life for components, as warranty limits for the future performance of a specified number of systems with standby units, and in various other app…
Time-Space Domain Availability Analysis Under Reliability Impairments
2019
Availability and reliability are two essential metrics for the design, deployment, and operation of future ultra-reliable low latency communication (URLLC) networks. Despite a vast amount of research efforts toward URLLC, very little attention has been made on the ultra-reliable communication (URC) aspect of URLLC from a dependability perspective. As an effort toward achieving anytime and anywhere communication, this letter consolidates a dependability theory-based availability concept for individual users by taking into account reliability impairments that affect URC in both spatial and temporal domains . To this end, we perform per-user availability analysis by considering channel status …
A Joint Time-Space Domain Analysis for Ultra-Reliable Communication in 5G Networks
2018
Reliable communication is a fundamental service level agreement criterion in wireless networks. Moreover, it is a performance indicator for ultra- reliable communication (URC) in emerging 5G networks. In URC, the quality of the delivered services to end-users ultimately depends on the availability of network resources as well as the quality of the received signal. Therefore, in order to analyze URC in cellular networks, both time- dependent spectrum availability and space-dependent service quality need to be considered. In this paper, we present a combined time and space domain analysis on network reliability based on a continuous time Markov chain model. To this end, we introduce a new rel…