Level Of Network Reliability Research Articles

Analysis of the Electric Power Distribution System Service Reliability Index at PLN Lancang Garam

The level of electrical energy demand in an area reflects the welfare of that community. The greater the use of electrical energy, the higher the community's standard of living, followed by the public's critical attitude towards everything that happens and influences lives, including electricity services. Generally, a network's reliability level can be seen from the size of the SAIDI and SAIFI values on the PLN (state electricity company) side. The calculation and reliability analysis results of the Lhokseumawe ULP above show that the total SAIFI index value is 2.68 times/year. The SAIFI Rayon Lhokseumawe reliability index is categorized as reliable because its value does not exceed the standard set by PLN in SPLN 68-2 of 1986, namely 3.2 times/year. The total value of the SAIDI index is 45.30 hours/year. The Lhokseumawe Rayon SAIDI reliability index is categorized as unreliable because its value exceeds the standard set by PLN in SPLN 68-2 of 1986, namely 21 hours/year. There are certainly differences in infrastructure, electrical equipment, and number of customers in 1986 compared to current years; this has a different influence on electricity reliability values such as SAIDI and SAIFI.

On the Reliability of Wireless Sensor Networks with Multiple Sinks.

The convergence of heterogeneous wireless sensor networks provides many benefits, including increased coverage, flexible load balancing capabilities, more efficient use of network resources, and the provision of additional data by different types of sensors, thus leading to improved customer service based on more complete information. However, despite these advances, the challenge of ensuring reliability and survivability remains due to low-cost sensor requirements and the inherent unreliability of the wireless environment. Integrating different sensor networks and unifying protocols naturally leads to the creation of a network with multiple sinks, necessitating the exploration of new approaches to rational reliability assurance. The failure of some sensors does not necessarily lead to a shutdown of the network, since other sensors can duplicate information and deliver data to sinks via an increased number of alternative routes. In this paper, the reliability indicator is defined as the probability that sinks can collect data from a given number of sensors. In this context, a dedicated reliability metric is introduced and examined for its effectiveness. This metric is computed using an algorithm rooted in the modified factoring method. Furthermore, we introduce a heuristic algorithm designed for optimal sink placement in wireless sensor networks to achieve the highest level of network reliability.

Energy-Efficient Opportunistic Routing Algorithm for Post-Disaster Mine Internet of Things Networks.

The Mine Internet of Things (MIoT), as a key technology for reconstructing post-disaster communication networks, enables a user to monitor and control the safety of an affected roadway. However, due to the challenging underground mine environment, the MIoT suffers from severe signal attenuation, vulnerable nodes, and limited energy, which result in a low level of network reliability for the post-disaster MIoT. To improve transmission reliability and reduce energy consumption, a directional-area-forwarding-based energy-efficient opportunistic routing (DEOR) approach for the post-disaster MIoT is proposed. DEOR defines a forwarding zone (FZ) for each node to route packets toward the sink. The candidate forwarding set (CFS) is constructed by the nodes within the FZ that satisfy the energy constraint and the neighboring node degree constraint. The nodes in the CFS are prioritized based on a routing quality evaluation, which takes the local attributes of the nodes, such as the directional angle, transmission distance, and residual energy, into consideration. DEOR adopts a recovery mechanism to address the issue of void nodes. The simulation results verify that the proposed DEOR approach outperforms the ORR, OBRN and ECSOR methods in terms of energy consumption, average hop count, packet delivery rate, and network lifetime.

RESEARCH OF FUNCTIONAL PARAMETERS OF INFOCOMMUNICATION NETWORKS 6G

The work presents the results of research into 6G technology, which will allow integrating all types of access in one mobile phone, ensuring smooth switching between services. New options for the use of mobile networks, such as sensing and artificial intelligence, are considered, which form new indicators of the quality of the information service – the resolution of sensing and the probability of output. For new applications, the prospects for further research into related indicators, such as flexibility and scalability to support own artificial intelligence services and network reliability level, are considered. Prospects for the development of electronic health care based on mobile communication systems with increased requirements for reliability, availability, security and confidentiality are considered. A platform for aerial mobility of various high-resolution sensors and cameras for various industries based on unmanned aerial vehicles has been investigated. The fundamental energy limitations of calculations related to information processing, which are an important step on the way to the successful deployment of 6G wireless networks, are considered. In the design of next-generation wireless communication networks, it has been determined that traditional AI optimization algorithms (such as federated learning) usually consider the bandwidth or delay of wireless connections as a weight for distributed multiprocessor data exchange, without considering the power energy bounds between different devices in different regions. This ambiguous consideration of AI energy limitations or power costs may lead to a large divergence between the design of a wireless network and the actual deployment of AI in the future. For this reason, equal importance must be attached to green AI and green communications. Therefore, when designing the architecture of the 6G information communication system, it is necessary to fully consider the impact of artificial intelligence models, algorithms and equipment on energy consumption to provide economic benefits to customers with corresponding operating costs of the system. The peculiarities of providing users with access to Internet services at any time through the same device regardless of their location, which is one of the ultimate goals of creating effective wireless networks, are discussed. The proposed concept of green AI called Oncefor-All (once and forever), according to which it is proposed to train an information communication network with further specialization during deployment will allow for efficient logical implementation on many devices, taking into account the given resource constraints. At the same time, terrestrial and non-terrestrial 6G networks will be fully integrated at the system level, ensuring the convergence of services, radio interfaces, networks and user devices. By organically combining these two access environments into one converged multi-layer heterogeneous network covering the entire globe, 6G technology will provide users with the same service. Ensuring the global delivery of mobile services will be an important aspect of the development of the 6G network.

Multi-Objective Model to Improve Network Reliability Level under Limited Budget by Considering Selection of Facilities and Total Service Distance in Rescue Operations

Sudden disasters may damage facilities, transportation networks and other critical infrastructures, delay rescue and bring huge losses. Facility selection and reliable transportation network play an important role in emergency rescue. In this paper, the reliability level between two points in a network is defined from the point of view of minimal edge cut and path, respectively, and the equivalence of these two definitions is proven. Based on this, a multi-objective optimization model is proposed. The first goal of the model is to minimize the total service distance, and the second goal is to maximize the network reliability level. The original model is transformed into a model with three objectives, and the three objectives are combined into one objective by the method of weighting. The model is applied to a case, and the results are analyzed to verify the effectiveness of the model.

Simulasi Modifikasi Konfigurasi Jaringan Spindel Menjadi Loop Tertutup Untuk Meningkatkan Keandalan Sistem Distribusi Menggunakan Software ETAP

Distribution reliability network rely on to any factor such as material quality, maintenance, operational pattern, protection device and also network configuration. In the spindle network the level of network reliability is level 3 (SPLN 52-3, 1983: 5). In order to leveling up the network reliability from level 3 to level 5 (zero down time)[2][3] we need to modify the protection system from overcurrent relay and ground fault relay to line differential relay in each distribution substation. Beside that Load Break Switch in each customer cubicle substation and in the connection substation should replaced by circuit breaker. Spindle network which operated open loop in the connection substation switch to normally close operated, so it can be called as closed loop network. This modification purpose is ther is no down time in case off ground fault or phase to phase sort circuit on the network cable. Before this kind of modification and the setting applied into real network, we make a simulation using an application called ETAP and no missmatch trip from 7 time experiment consist of ground fault and phase to phase short circuit in 7 cable

Wang–Landau sampling for estimation of the reliability of physical networks

Modern physical networks, for example in communication and transportation, can be interpreted as directed graphs. Network models are used to identify the probability that given nodes are connected, and therefore the effect of a failure at a given link. This is essential for network design, optimization, and reliability. In this study, we investigated three alternative ensembles for estimating network reliability using the Wang–Landau algorithm. The first performed random walks on a structure function having two possible states: connected and disconnected. The second used random walks on a reliability polynomial. The third combined random walks with the average of connecting probabilities. The accuracy and limitations of the three ensembles were compared by estimating the reliability of three network models: a bridge network, a ladder-type network, and a dodecahedron network. The simulation results showed that the use of a random walk on a structure function failed to produce estimates when applied to highly reliable networks in any of the three network types. The other two approaches performed efficiently for bridge or ladder-type networks at any level of network reliability. The random walk on a probability space using the 1∕t algorithm was the only ensemble that was able to yield accurate estimates for a dodecahedron network, though even this failed at the highest level of network reliability. The other two methods failed to converge within 108 Monte Carlo trials. The use of the average of connecting probabilities required a shorter computation time when applied to a large network. Methods that can reduce variance for large, highly reliable networks require further investigation.

ВИЯВЛЕННЯ АТАК ТИПУ DOS В МЕРЕЖЕВОМУ ТРАФІКУ ЗА ДОПОМОГОЮ ВЕЙВЛЕТ-ПЕРЕТВОРЕННЯ

Мета роботи. Кількість мережевих вторгнень і атак набирає все більш критичні позиції, які виходять з даних аналітичних агентств кібербезпеки. У 21 столітті майже всі організації не є на 100% захищені. В організаціях з передовими технологіями захисту можуть бути проблемні моменти в ключових елементах - розуміння зловмисником відомих технологій захисту. У таких ситуаціях використання інших способів виявлення може бути ключовим моментом в захисті від мережевої атаки. Є безліч методів перевірки рівня захищеності: аналіз безпеки систем і додатків, тестування на проникнення, оцінка обізнаності персоналу в питаннях інформаційної безпеки і т.д. Однак через постійні зміни технологій, появи нових інструментів і злочинних груп виникають нові типи ризиків, які важко виявити за допомогою традиційних способів аналізу захищеності. На цьому тлі найбільш поглиблений і прогресивний метод до тестування безпеки з перетворенням сигналу і вивченням вхідного трафіку буде здатний підвищити рівень надійності мережі. Методи дослідження. Кібератаки в різних форматах, особливо відомі, постійно вимагають безперервну оцінку захищеності інформаційних систем. Ці отримані дані необхідні для вивчення і дослідження фахівцями для їх подальшого використання. Один із перспективних методів Data mining, який є прогресивним і поглибленим можливо вважати вейвлет-перетворення. Алгоритм вейвлет-перетворення слід застосовувати для аналізу дискретних даних. Це важливо коли потрібна висока швидкість обробки та аналізу інформації. Що є актуальним пунктом для вирішення завдання захисту мережі інтернет. Отримані результати. Виконано аналіз алгоритмів вейвлет перетворення як для очитски вхідного трафіку від шуму, так і для виявлення мережевої аномалії. Докладно розглянуті основні етапи застосування і реалізації системи виявлення, що використовує порогові значення вейвлет-коефіцієнтів для виявлення мережевої атаки і аномалії. Наукова новизна. Розроблена модель виявлення відповідно до ефективного алгоритму вейвлет-перетворення, яка комплексно стежить за поточним станом мережі, і повідомляє при ризики виникнення несприятливих подій. Практичне значення. Розглядаючі мережеві атаки типу DOS і практичне реагування на можливі атаки, у разі використання вейвлет-перетворення для безпеки, можливо підвищити захист системи з виявлення до непомічених загроз. Щоб зупинити зловмисників на ранніх стадіях атаки і запобігти матеріальним збиткам для бізнесу слід звернути увагу саме на цей метод Data mining.

МЕТОДИКА ОЦЕНКИ КОЭФФИЦИЕНТА ГОТОВНОСТИ СИСТЕМЫ С РЕЗЕРВИРОВАНИЕМ. ПАССИВНЫЙ РЕЖИМ

The use of fiber-optic communication lines allows for the transfer of huge amounts of information per unit of time. Even short-term failures significantly affect the quality of services provided. The level of network reliability depends on how resilient the network infrastructure is to failures and how quickly recovery occurs after them. Reliability guarantees are the main component of quality of service agreements between operators and consumers. Most often, redundancy is used to ensure the required level of reliability indicators. The disadvantage of this approach is the high cost of network bandwidth, the advantage - is a short time to switch at the reserve after a failure is detected. In order to reduce costs, in some cases, the 1:N backup option is used (one backup path is allocated for N working paths). In this paper, we consider the case of 1:2, when one backup path is allocated for two working paths. In this case active and passive switching modes are possible. When switching is active, if both working paths fail, the traffic of one of them switches to the backup path. After restoring the working path, traffic switches to the restored path, i.e. the backup path is freed. It is replaced by traffic from another failed path. A special feature of passive mode consists in that after the backup path is released, it does not deal with the traffic of the second failed path. There are several ways to restore traffic over a failed work path:. the second working path starts to recover after the first one is restored; the second working path starts to recover simultaneously with the first one. In either case, the traffic of the first path is switched back from the backup to the working path after it is restored. This paper presents a method for calculating the conditional probability that the backup path will be used for transmitting traffic from one of the working paths if both paths fail. The formula for calculating the unavailability factor of working paths is given.

Reliability and Connectivity Analysis of Vehicular Ad Hoc Networks Under Various Protocols Using a Simple Heuristic Approach

Vehicular ad hoc networks (VANETs) provide alternative technology solutions to various transportation problems, and they provide a communication solution in intelligent transportation systems. However, the reliability and connectivity of VANET networks are subjects of concern. In building any routing protocol, a minimum level of network reliability must be ensured, which requires conducting a reliability analysis in order to investigate the different factors that affect reliability. Conducting a real-world reliability analysis is very expensive, and it requires significant preparation. Simulations are computationally costly due to the high number of available paths between the source node and the destination. In this article, a simplified approach is conducted that is mainly based on a simulation model of a road-type environment for a VANET network. A heuristic approach is developed for calculating the reliability based on the highest probability paths using the Dijkstra algorithm and the inclusion-exclusion approach for calculating the reliability of a given path. For vehicle-to-vehicle (V2V) communication, short-range protocols were considered-ZigBee (802.15.4), WiFi (IEEE 802.11), and Bluetooth (802.15.1)-as well as their standards for data rates, association time, and transmission range. On the other hand, the IEEE 802.11b was used for vehicle-to-roadside (V2R) communications. Another parameter that was considered was the speed limit of the road environment, and three types of road environments were evaluated: highway, urban, and mixed. Other factors that were considered were the number of vehicles, the number of roadside units, and the type of message that was transmitted. The effects of all of these elements on the connectivity of the network were studied.

An integrated measure of accessibility and reliability of mass transit systems

The growth of a city or a metropolis requires well-functioning transit systems to accommodate the ensuing increase in travel demand. As a result, mass transit networks have to develop and expand from simple to complex topological systems over time to meet this demand. Such an evolution in the networks’ structure entails not only a change in network accessibility, but also a change in the level of network reliability on the part of stations and the entire system as well. Network accessibility and reliability are popular measures that have been widely applied to evaluate the resilience and vulnerability of a spatially networked system. However, the use of a single measure, either accessibility or reliability, provides different results, which demand an integrated measure to evaluate the network’s performance comprehensively. In this paper, we propose a set of integrated measures, named ACCREL (Integrated Accessibility and Reliability indicators) that considers both metrics in combination to evaluate a network’s performance and vulnerability. We apply the new measures for hypothetical mass transit system topologies, and a case study of the metro transit system in Seoul follows, highlighting the dynamics of network performance with four evolutionary stages. The main contribution of this study lies in the results from the experiments, which can be used to inform how transport network planning can be prepared to enhance the network functionality, thereby achieving a well-balanced, accessible, and reliable system. Insights on network vulnerability are also drawn for public transportation planners and spatial decision makers.

Reliable and energy efficient wireless sensor network design via conditional multi-copying for multiple central nodes

Design of reliable wireless sensor networks considering energy efficiency is of utmost importance given their specific application domains and technical properties. As a contribution to the vast literature on resilient and fault tolerant network design, this paper offers a novel energy efficient conditional multi-copy and multi-path routing strategy. The motivation is to use limited energy of sensors as efficiently as possible and to improve network reliability and security via restricted redundant data generation. Namely, rather than all only the data passing through some central nodes are duplicated as a precaution against their malfunctioning. A limited number of nodes with higher data transmission allowance are determined as central at the design stage considering lifetime maximization objective. Consequently, 0–1 mixed integer programming models of two variants of the proposed strategy are presented in order to determine optimal routing. Moreover, several valid inequalities so as to improve solution times with commercial solvers and an efficient heuristic method for finding good solutions for large instances in reasonable times are proposed. Extensive test results show that simple restricted multi-copy strategies where every sensor duplicates its data are improved since the proposed strategies provide comparable levels of network reliability and yet extend network lifetime significantly.

Determining Reliable Networks of Prepositioning Materiel Warehouses for Public-Sector Rapid Response Supplies

Events such as natural disasters or combat operations require a rapid response capability from humanitarian service providers and military organizations. Such organizations can decrease their response times through theprepositioningof materiel in forward warehouses, reducing the time needed to transport items to the site of need. A particular challenge to the development of networks of prepositioning warehouses is that the warehouses themselves may be impacted by the very disruptions that drive demands for prepositioned materials. The objective of this research is to identify a reliable networkposture, which is a set of utilized facility locations and an allocation of materiel to those locations, that can satisfy time-sensitive delivery requirements to potential locations around the globe, ensuring that demands can be satisfied even in the event of loss of access to a subset of storage sites (along with said sites’ materiel), all at minimum total cost. We develop new optimization formulations to account for differing levels of network reliability, all reflecting the time-sensitive environment faced by rapid response operations. We demonstrate an application of this methodology using rapid response material prepositioned by the US Air Force.

Operational reliability assessment of power systems based on bus voltage

Bus voltage is a direct reliability indicator of a transmission network because it is related to system reactive and active power balance especially during a contingency state. This study proposes a technique to evaluate network operational reliability based on bus voltage. Two new voltage related bus reliability indices are proposed to represent bus reliability. Network reliability levels under various operating conditions and contingency states are evaluated and presented by probabilities of system voltage being in normal, under-voltage, critical and collapse zones. The probabilistic voltage margin to the collapse point for each bus is evaluated to provide information for system operator regarding the risk under system random failures and load uncertainty. The IEEE 30-bus system and a practical 220 kV Taiyuan power system in Shanxi Province of China have been analysed to illustrate the proposed techniques.

Stochastic network design for disaster preparedness

This article introduces a risk-averse stochastic modeling approach for a pre-disaster relief network design problem under uncertain demand and transportation capacities. The sizes and locations of the response facilities and the inventory levels of relief supplies at each facility are determined while guaranteeing a certain level of network reliability. A probabilistic constraint on the existence of a feasible flow is introduced to ensure that the demand for relief supplies across the network is satisfied with a specified high probability. Responsiveness is also accounted for by defining multiple regions in the network and introducing local probabilistic constraints on satisfying demand within each region. These local constraints ensure that each region is self-sufficient in terms of providing for its own needs with a large probability. In particular, the Gale–Hoffman inequalities are used to represent the conditions on the existence of a feasible network flow. The solution method rests on two pillars. A preprocessing algorithm is used to eliminate redundant Gale–Hoffman inequalities and then proposed models are formulated as computationally efficient mixed-integer linear programs by utilizing a method based on combinatorial patterns. Computational results for a case study and randomly generated problem instances demonstrate the effectiveness of the models and the solution method.

Determination of Optimal MR&R Policies for Retaining Life-Cycle Connectivity of Bridge Networks

AbstractBridge management problems are computationally difficult to solve when considering network connectivity, because all bridges must be analyzed together. Past research has usually adopted simulation-based numerical methods, which are inaccurate and time-consuming. In this paper, an analytical and efficient approach is presented to determine the optimal maintenance, rehabilitation, and replacement (MR&R) plan. The objective is to ensure an adequate level of network reliability at the lowest possible life-cycle maintenance cost. Instead of considering the evolution of network reliability over the whole life cycle, the optimization is formulated with a constraint on the lower bound of network reliability, which reduces the network-level problem to one of optimizing the set of reliability levels for individual bridges. For simple decomposable networks, the network-level optimization can be tackled with standard techniques in polynomial time. For complex networks that are nondecomposable, an algorithm is...

Trust-based Adaptive Routing for Smart Grid Systems

Smart Grid is the trend of next generation electrical power system which makes the power grid intelligent and energy efficient. It requires high level of network reliability to support the two-way communication among electrical services, electrical units such as smart meters, and applications. The wireless mesh network infrastructure can provide redundant routes for the Smart Grid communication network to ensure the network availability. Also due to its high level of flexibility and scalability features that make it become a promising solution for Smart Grid. However, similar with many other distributed ad-hoc networks, trust is a critical issue for wireless mesh networks. In this paper, we proposed a novel trust-based geographical routing protocol, named as Dynamic Trust Elective Geo Routing (DTEGR), which allows peers in a Smart Grid system to adjust their interaction behaviors based on the trustworthiness of others. The simulation studies have confirmed that DTEGR can achieve better routing performance in different network scenarios, and also to achieve high level of reliable data transmission in Smart Grid communication networks.

A New Reliability Evaluating Method for Distribution Network

In order to improve the reliability evaluation to the distribution network, uncertainty factors about aging of components are considered under conventional reliability analysis of distribution system in the paper. The relationship between unavailability of aging of components and time (or limit age of components) is analyzed. Then the reliability indices are calculated by FMEA (Failure Mode and Effect Analysis). Finally distribution network reliability level is distinguished and the measures on improving the power distribution system reliability are presented.

The Reliability Evaluating Method Considering Component Aging for Distribution Network

In order to improve the reliability evaluation to the distribution network, uncertainty factors about aging of components are considered under conventional reliability analysis of distribution system in the paper. The relationship between unavailability of aging of components and time (or limit age of components) is analyzed. Then the reliability indices are calculated by FMEA (Failure Mode and Effect Analysis). Finally distribution network reliability level is distinguished and the measures on improving the power distribution system reliability are presented.

Effectiveness of chosen robust estimation methods compared to the level of network reliability

Effectiveness of chosen robust estimation methods compared to the level of network reliability The work presents the results of studies on dependence of effectiveness of chosen robust estimation methods from the internal reliability level of a geodetic network. The studies use computer-simulated observation systems, so it was possible to analyse many variants differing from each other in a planned way. Four methods of robust estimation have been chosen for the studies, differing substantially in the approach to weight modifications. For comparative reasons, the effectiveness studies have also been conducted for the very popular method in surveying practice, of gross error detection basing on LS estimation results, the so called iterative data snooping. The studies show that there is a relation between the level of network internal reliability and the effectiveness of robust estimation methods. In most cases, in which the observation contaminated by a gross error was characterized by a low index of internal reliability, the robust estimation led to results being essentially far from expectations.