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The paper presents a novel Telepower (−48V DC) reliability method, directly utilising site asset data in simulation software, to determine the effectiveness of battery replacement programs. Reliability is often estimated by a simple count of the number of outages per annum. This approach has many shortcomings because a count of outages can change dramatically even when the reliability of the physical...
Communication between air traffic controllers and pilots remains a vital part of air traffic control operations, and communication problems can result in hazardous situations. The modern Air Traffic Management (ATM) system has independent direct communication channels (CC) for each controllers operating at different radio frequencies. Currently, the main method of improving the reliability of controller's...
Large-scale disasters (such as earthquake, flood, tornado) may cause severe network failures, leading to massive disruptions and data loss. Particularly, the aftermaths of disasters may further threaten the residual network and impact the existing/survived service connections. In this paper, we study a reliability based restoration scheme for recovering the impacted (disrupted and/or reliability-decreased)...
Disasters, such as earthquake, tsunami, tornado, and malicious attack, may cause large-area, geographically correlated and/or cascading failures in telecom networks, leading to massive connection disruptions and instability of network state. In this paper, we study survivability strategies to alleviate the effect of disasters to telecom networks, e.g., Wavelength-Division-Multiplexing (WDM) optical...
The promise of SDN/NFV to offer enhanced functionalities to the service provider networks is now tangible as both technologies have started being steadily investigated and experimentally demonstrated. However, a number of research challenges have not been fully addressed yet. More specifically, a limited interest has been devoted on how to assure reliability and QoS performance while data traverse...
In the 5G era, it is expected that various services will be provided on network slices, which are virtualized network resources. Unlike the uniform service level provided in the current Internet, a network slice has to support multiple service levels for various types of services such as IP telephony, Internet-access and IoT/M2M. Because their requirements are quite different. IP telephony and Internet-access...
This paper proposes a new high-speed method of approximating system reliability. This method is an improved version of truth table approximation. While truth table approximation is simple and widely applicable, its approximation error becomes unreasonably poor as the failure probabilities of the components become worse. Here, we improve its accuracy. The key idea is to use information of non-enumerated...
Network Function Virtualization (NFV) transforms the traditional service provision architecture into a software-based structure. In NFV, Virtual Network Functions Forwarding Graph (VNF FG) [1] is used to describe the logic connections among the VNFs placed on the Physical Network (PN). And end-to-end services are represented as flows traverse the VNF FG. To improve the reliability of the services,...
Air Traffic Management (ATM) systems represent essential infrastructure that is critical for flight safety. Communication is a key element in the present ATM system. Communication between air traffic controllers and pilots remains a vital part of air traffic control operations, and communication problems can result in hazardous situations. The modern ATM system has independent direct communication...
Flow classified one-to-all reliability is a reliability measure defined as the probability of traffic volume between a specified node and all other nodes being not less than a threshold value. While this reliability measure is very useful in the reliability design of telecommunications networks of developing countries, it has a problem that its evaluation time becomes intolerably long if network size...
A framework for the continuous delivery of mission-critical network services is proposed. The risk involved is assessed in a binary way, i.e., there is no risk until the network system supports the services up to the intended duration; otherwise, the mission fails and this gives rise to failure impact. The proposed framework is used to allocate network resources.
Double homing is effective especially for disasters; and for it to succeed on telecommunications networks, two disjoint paths are assigned between two pairs; but assigning such disjoint paths is not easy because telecommunications networks are large and complicated systems. We previously proposed a method to overcome this difficulty by partitioning a network into subnetworks that never share any common...
In the presence of multiple faults (multiplicity no more than t) of system diagnostics. The conditions under which the status of each module of the system is determined only on the outcomes of testing modules having physical relation with him (conditions self-definable). The conditions diagnosed systems in cases where for any of the modules is not the conditions self-definable.
Risk and uncertainty are considered crucial and extremely problematic for economic and industrial systems. They must be handled with preciseness so that decision makers need first to establish an action plan for their mitigation by estimating the associated low frequency of failures and adverse events. This paper proposes a combination of solutions based on reliability estimation using enumerating...
How to design an effective and efficient reliability prediction method for services is one of the important topics in the research field of Services Computing. With the increasing complexity of network environments, the effect of network environments and other environments related properties on service reliability cannot be neglected any more. However, most of the existing reliability prediction methods...
A model of information and communication system is presented in the form of 4 main states: serviceable and unserviceable, each of them may be both in operative and standby modes. The main object of analysis is failure and appropriate parameters: mean time between failures, availability coefficient, reliability probability, probability of survivability, an average total risk of failure probability.
High performance systems require high levels of reliability. Many functions involved in telecommunication and IT networks have reliability requirements that can only be achieved by introducing redundant resources. In the telecom sector, recently, there has been a significant effort on moving carrier grade systems and functions to virtualized network infrastructure. The management and coordination...
A method is proposed for evaluating telecommunications network reliability considering traffic path assignments that produces a very useful reliability measure, “one-to-all reliability,” that can be evaluated exactly without the need for assuming highly reliable nodes and links. The key idea is to apply a factoring method to the enhanced model of Anzai et al. Evaluation showed that this method achieves...
With the rapid development of communication technologies, the software radio becomes an emerging technology for flexible radio systems and have guided us into new fabulous communication tools, which resulted in improved radio communication performance, reliability, flexibility and increased value to the user to facilitate their daily life. One of the most highlighted topics of the developed communication...
Many complex systems have functional interdependency between each other and can be modeled as interdependent networks. The failure of a small fraction of nodes in interdependent networks may lead to catastrophic cascading failures across network borders. Starting from a model of static interdependent networks, by introducing lifetime for each component, we study the reliability properties and lifetimes...
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