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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 of the interdependent networks to which these components belong. Depending on the lifetime of the network components, the trigger of cascading failures will shape the interdependent networks reliability. In this framework, we analyze the evolution of the reliability properties of interdependent networks, and compare them with single networks. Interdependent SF networks are found to have lower reliability than interdependent ER networks. [ABSTRACT FROM PUBLISHER]

The role of network reliability in the analysis of Critical Infrastructures (CI) is investigated showing that the traditional approach must be extended in two directions: to include the packet propagation time along the links for real time analysis, and to include networks in which many sources may be variously connected to many sinks. A case study of a SCADA system controlling a power grid, originated from the EU Project MICIE (MICIE — Tool for systemic risk analysis and secure mediation of data exchanged across linked CI information infrastructures) [6], is examined in details, by considering the system in normal operation and when perturbed by malicious attacks. The paper describes an analytical model that can provide timely and accurate information about the reliability status of the system, and that can rapidly be adapted to the changing configurations of the interacting networks. The aim of this work is to explore the feasibility of providing the human operators with a reliability monitor that assists them in checking the status of the system. [ABSTRACT FROM PUBLISHER]

This paper is focused on the propagation of failures within a core telecommunication network (i.e. virus or malicious code spreading), which are commonly represented using epidemic models. This work conducts an analysis of the vulnerability of five core telecommunication networks subject to different epidemic attacks. The difference between the attacks relies on the method used to select the initial set of infected nodes. As a novelty, the investigation is focused on the initial stage of the epidemics (first 48 hours). The analysis is carried out taking into account the topological connectivity of the networks. Results are presented in two phases. The first one concerns the first 24 hours of the epidemics evolution and shows the reaction of core networks to different types of epidemic attacks. The second one is focused on the time frame between 24 and 48 hours and presents a study of the repairing times needed to eradicate the epidemics. Results show that the core telecommunication networks react differently depending on the type of epidemics. Thus, different repairing times need to be applied in order to maintain a specific level of connectivity of the networks. [ABSTRACT FROM PUBLISHER]

Nowadays, the end-users have multitude of offers that make service prices decrease in using a network environment with multiple-operators and multiple-network. Consequently, the competition between network providers increases. The customer is today in a strong position with ability to select the best one among different competing providers. Besides similar pricing schemes, which are a useful decision aid for users, their choices are also influenced by expected and experience quality. So, the interest of service providers in how users perceive usability, reliability, quality and price-worthiness has increased. As a consequence, the QoE notion has been introduced to help service providers to take into account the user perception and satisfaction. In this paper, we propose an end-to-end QoE model applied to a Content Distribution Network architecture. [ABSTRACT FROM PUBLISHER]

The study on the parameters of network reliability has been one important part of the network quantitative characteristics while current research often focused on the connectivity lacking of the network applications. Whether the network applications can meet users' demands or not is one of the important examination indexes in communication networks. The reliability parameters on communication networks are the basis and important part to the network reliability. According to the general international standards, this paper established a system of communication network application parameters, definitions and their relationships at the basis of reliability connotations. [ABSTRACT FROM PUBLISHER]

The paper proposes a section-partition-based method for packet partitioning and restructuring, aiming at meeting the rigorous requirement of transmitting a great abundance of data reliably and real-timely in some specific situation in that the traditional UDP protocol has high efficiency but poor reliability. The time limit can be reset by adaptive congestion control algorithm of MIRD ( Multiplicative Increase Reduced Decrease ) by which the data can be transmitted reliably and also the fairness and stability of the bandwidth utilization can be improved. The method is validated to improve the reliability of the audio data transmission by the experiment. [ABSTRACT FROM PUBLISHER]

Through researches on design and application of wireless sensor network in botanic garden environment monitoring system, enforcing the deployment of wireless sensor network in areas that traditional wired network unable to reach, hence support task systems. This paper discusses the features of wireless self-organize sensor network and the feasibility of adopting this technology in botanic garden; moreover, proposes an application design. Through study, in application scenario which is low in message delay and duty ratio, applying distributed MD protocol in wireless self-organize sensor network as governing channel access control protocol is practicable and effective. This research is an innovation research in intelligent botanic garden environment monitoring. [ABSTRACT FROM PUBLISHER]

This paper pioneers the application of deterministic and stochastic index studies in substation LAN architecture evaluation. The paper studies star, ring and hybrid star-ring configurations and their invulnerability, investigates their suitability for mission critical time stringent protection and control function applications in substation automation systems. The proposed invulnerability analysis method is simple, efficient and practical. Studies on the commonly used star, ring and hybrid star-ring configurations indicate that the hybrid star-ring architecture is of the highest invulnerability. [ABSTRACT FROM PUBLISHER]

Opportunistic routing is applied to wireless multi-hop network. It makes full use of the characteristic of wireless network, decreasing the retransmission of data packet, increasing the throughput. At present, opportunistic routing is based on the assumption that the node and link are completely reliable. This paper proposes a reliable opportunistic routing, which evaluates reliability of node using terminal-pair reliability index, combining the traditional opportunistic routing. The protocol can transmit data packet more reliably by reliable forwarder list, thus, decreases end-to-end delay, increases the throughput. The result of NS2 simulation shows the availability of our protocol. [ABSTRACT FROM PUBLISHER]

Telecommunication operators must manage many types and models of power equipment from many manufacturers each with different characteristics. With Telco's globally reporting strong pressure on CAPEX reduction, it is important to develop capability not only of predicting end-of-life of equipment, but also of managing the vast number of types, makes and models used in a variety of environments. Delayed replacement results in higher service disruption risk while early replacement places considerable pressure on CAPEX budgets. We have developed an Equipment Reliability Analysis (ERA) program for telecommunication power equipment life cycle replacement. Rectifiers, batteries and UPS life data are grouped by features including technology, manufacturer make/model, life-data analysis from field failure data, and equipment tear-down analysis for life cycle replacement decisions. Replacement decisions are based on a number of inputs, including field experience, type of application, defect data and life data analysis. [ABSTRACT FROM PUBLISHER]

Next Generation Networks (NGNs) need to handle both high level of service reliability by network survivability mechanism of overprovision redundant network resources (i.e., Blue criteria), as well as minimizing energy cost by turning off unnecessary network resources (i.e., Green criteria). There is an inherent contradiction on satisfying both these Blue and Green requirements simultaneously. In effect this challenging problem can be formulated as a global optimization problem, where the network working and backup components such as nodes and links, and their energy cost is considered as a resource, and their utilization should be minimized. The case studies confirm that the BlueGreen approach is effective to integrate both service reliability and energy efficiency to achieve the specified BlueGreen target. [ABSTRACT FROM PUBLISHER]

In the paper is given availability analysis of telecommunication network build on synchronous digital hierarchy (SDH) and optical ground wires (OPGW). We have examined three special cases which characterize network availability, with real values of failure rates. It is given availability dependence on repair times for multiplexer and cable and basis on previous operating experience, review of existing status and suggestions for improvement. We have reconsidered the classical E1 service. Charts of the modeled paths are given at the end. [ABSTRACT FROM PUBLISHER]

The application of developed software simulator for reliability calculation of a complex communication network is presented in this paper. The communication network is comprised from nodes (communication stations) and links between them. Simulator is implemented in GPSSWorld program. It executes over 500000 iterations for a few seconds. The reliability estimation is based on exponential distribution, which can be applied for systems with electronic elements. The comparison of results with simulation method based on Monte Carlo method is also presented. The results show that both methods can be successfully applied. [ABSTRACT FROM PUBLISHER]