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Abstract: Space weather, the shorter-term variable impact of the Sun’s photons, solar wind particles, and interplanetary magnetic field upon the Earth’s environment, adversely affects our technological systems. These technological systems, including their space component, are increasingly being seen as a way to help solve 21st Century problems such as climate change, energy access, fresh water availability, and transportation coordination. Thus, the effects of space weather on space systems and assets must be mitigated and operational space weather using automated distributed networks has emerged as a common operations methodology. The evolution of space weather operations is described and the description of distributed network architectures is provided, including their use of tiers, data objects, redundancy, and time domain definitions. There are several existing distributed networks now providing space weather information and the lessons learned in developing those networks are discussed along with the details of examples for the Solar Irradiance Platform (SIP), Communication Alert and Prediction System (CAPS), GEO Alert and Prediction System (GAPS), LEO Alert and Prediction System (LAPS), Radiation Alert and Prediction System (RAPS), and Magnetosphere Alert and Prediction System (MAPS). [Copyright &y& Elsevier]

An incremental least‐mean M‐estimate algorithm is proposed for distributed network, which minimises a robust M‐estimator‐based cost function against impulsive noise via the gradient descent method. Moreover, based on the same frame for implementation, an incremental distributed least‐mean p‐power algorithm is presented for combating impulsive noise. Simulations verify the superiority of the proposed algorithms in the presence of impulsive noise relative to some existing incremental distributed algorithms. [ABSTRACT FROM AUTHOR]

A variable step‐size distributed incremental normalised least mean square (DINLMS) algorithm is proposed, in which the time‐varying step‐size of each node in the distributed network is obtained by minimising a posterior estimation error at that node. It overcomes the drawback that fast convergence rate with high steady‐state misalignment or low steady‐state misalignment with slow convergence rate, which always exists in the traditional DINLMS. The simulation results show that the proposed algorithm could achieve a better performance. [ABSTRACT FROM AUTHOR]

An algorithm of reliability indexes was studied for evaluating the reliability of the distributed network with QoS requirements, which is constructed in the environment of interconnection network. Firstly, according to the requirements of QoS, all routes satisfying the QoS requirements were calculated between distributed nodes in weighted networks. Then the network adjacency matrix was constructed according to these routes, and the disjoint network state set was obtained by decomposition transformation and conformity transformation of the adjacency matrix. The calculation expression of reliability indexes was obtained according to the disjoint network state set, find then the reliability indexes were accomplished. The correctness of each key step of the proposed algorithm was discussed. Calculation examples and experimental results verified the rationality of this algorithm. [ABSTRACT FROM AUTHOR]

Abstract: Pantodon buchholzi, the African butterfly fish, inhabits an ecological niche just below the water surface. At that position, each eye necessarily views into the air through the surface of the water and into the water. Since Pantodon is an obligatory surface feeder, the ventral retina viewing the aerial environment provides all visual information for prey acquisition. The visual pathway of this fish reflects the divided visual field with structural differences in the retina and brain corresponding to the different views. In this study, we describe a specific type of neuron in the tectum that, due to its intrinsic structure, likely integrates visual and mechanoreceptor inputs. Because of its spatial distribution, this type of neuron is a candidate as a basic element in a network involved with prey acquisition. [Copyright &y& Elsevier]

In this paper, a Web service composition architecture based on structured P2P network is proposed. Semantics is used to achieve service accurately matching and user personality customization. Through Web service virtual mapping(WVM) association the fast computing of distributed service composition based on the service function is also implemented. The Web service composition architecture and distributed service composition algorithm proposed in this paper solve a series of existent problems in service discovery and composition in distributed environment, and provide a service composition result meeting user personality requirement. At the same time, they improve the efficiency of service composition calculation. [ABSTRACT FROM AUTHOR]

Symmetric key agreement is significant to security provisioning in sensor networks with resource limitations. A number of pairwise key pre-distribution protocols have been proposed, but their scalability is often constrained by the conflict between the desired probability of sharing keys between neighboring nodes and the resilience against node capture attacks under a given budget for storing keying information within each sensor. In this paper, we propose LKE, a self-configuring in-situ key establishment scheme targeting large-scale sensor networks. LKE employs location information for a deterministic key space generation and keying information distribution. For uniformly distributed networks, LKE exhibits strong resilience against node capture attacks and achieves a high key-sharing probability (close to 1) at the expense of a small amount of memory overhead. An improvement over LKE, termed as iLKE, is also proposed. iLKE is topology-adaptive, and therefore works well for both uniform and non-uniform network models. We conduct both theoretic analysis and simulation study to evaluate the performances of LKE and iLKE. [ABSTRACT FROM PUBLISHER]

Today's Internet is a massive, distributed network which continues to explode in size as e-commerce and related activities grow. The heterogeneous and largely unregulated structure of the Internet renders tasks such as dynamic routing, optimized service provision, service-level verification, and detection of anomalous/malicious behavior increasingly challenging tasks. The problem is compounded by the fact that one cannot rely on the cooperation of individual servers and routers to aid in the collection of network traffic measurements vital for these tasks. In many ways, network monitoring and inference problems bear a strong resemblance to other "inverse problems" in which key aspects of a system are not directly observable. Familiar signal processing problems such as tomographic image reconstruction, system identification, and array processing all have interesting interpretations in the networking context. This article introduces the new field of network tomography, a field which we believe will benefit greatly from the wealth of signal processing theory and algorithms [ABSTRACT FROM PUBLISHER]

The Agriculture Network Information Center (AgNIC), , is a single entry point to authoritative information and resources available electronically in agriculture and the related sciences. From its inception, AgNIC relied on the National Agricultural Library and the United States land-grant university network to develop and nurture both its governance and content. The main components of AgNIC are: AgDB, AgCal, and the Online Reference Service. AgDB provides descriptive information about databases. Ag- Cal is a calendar listing for information about agricultural meetings. The Online Reference Service provides specific agricultural information through AgNIC subject Web sites and access to direct reference service by experts. This article explores the development of AgNIC and its technical aspects to date. [ABSTRACT FROM PUBLISHER]

Considering the increasing scale and severity of damage from recent cybersecurity incidents, the need for fundamental solutions to external security threats has increased. Hence, network separation technology has been designed to stop the leakage of information by separating business computing networks from the Internet. However, security accidents have been continuously occurring, owing to the degradation of data transmission latency performance between the networks, decreasing the convenience and usability of the work environment. In a conventional centralized network connection concept, a problem occurs because if either usability or security is strengthened, the other is weakened. In this study, we proposed a distributed authentication mechanism for secure network connectivity (DAM4SNC) technology in a distributed network environment that requires security and latency performance simultaneously to overcome the trade-off limitations of existing technology. By communicating with separated networks based on the authentication between distributed nodes, the inefficiency of conventional centralized network connection solutions is overcome. Moreover, the security is enhanced through periodic authentication of the distributed nodes and differentiation of the certification levels. As a result of the experiment, the relative efficiency of the proposed scheme (REP) was about 420% or more in all cases. [ABSTRACT FROM AUTHOR]

Blockchain is not widely applied in various fields due to the critical issue of scalability as part of the blockchain trilemma. This issue arises during consensus among the nodes in a public blockchain. To address the issue of low scalability with proof-of-work (PoW) consensus, various methods have been proposed for transaction per second (TPS) improvement. However, no such methods include an improvement in the consensus step. Therefore, to improve PoW public blockchain scalability, it is important to shorten the time required for PoW consensus. This paper proposes a method for minimizing the block intervals that occur during consensus over a PoW blockchain network. A shortened block interval leads to an increase in the probability of three different attacks: selfish mining, double-spending, and eclipse attacks. According to an experiment using Ethereum, with a typical PoW blockchain, it is inevitable to provide rewards for stable block mining in competition between mining pools. To find an optimal block interval in the PoW consensus algorithm, we conducted a four-step experiment. The purpose of this experiment was to verify the difficulty level and issues with Mainnet security. Therefore, considering stale block mining rewards, an optimal block interval is proposed. The Ethereum TPS was improved by at least 200%. Given this finding, it is considered possible to achieve a similar improvement in a different PoW blockchain. On balance, even if the block interval is shorter than that of the PoW Mainnet, network security falls by only 1.21% in Testnet, even with a rise in the stale block rate, while performance is increased at up to 120 TPS, which is three times higher than that in Mainnet. [ABSTRACT FROM AUTHOR]

In this, the second part of a two-part paper, the required time for establishing a mobile packet radio network using the virtual circuit and time division multiple access protocol developed in Part 1 is analysed. Tools are developed to determine the virtual circuit and network set-up times in terms of the channel bandwidth allocated to establish and maintain the network. The tools are then extended to include the effects of user mobility. Then these results are combined with the network capacity results of Part 1 to analyse the trade-off between the data rate and set-up time of the network. Next a hierarchical architecture is proposed and the network data rate versus set-up time trade-off of this architecture is analysed using these tools. This architecture is shown to both provide a higher data rate and establish faster than flat networks of the same number of nodes. [ABSTRACT FROM AUTHOR]

A distributed time-slot assignment protocol is developed for a mobile multi-hop broadcast packet radio network, using time division multiple access channel access and virtual circuit switching. The protocol eliminates the single point failure mode of centralized network management and the delays of centralized processing. It is applicable to the user-to-user communications functions of such systems as the U.S. Army's enhanced position location and reporting system (EPLRS). The important functions of the distributed protocol, including time-slot assignment, virtual circuit set-up, and network synthesis, are identified, and implementing algorithms are presented and verified. The performance analysis of the protocol is divided into two parts. In this paper, Part 1 of the performance analysis, the capacity of a network using this protocol is studied and a tool is developed to design the network capacity by trading off among the network area, the transmission range, and the number of packet radio units. Since these results are not in closed form, numerical results provide insight into these parameters. In Part 2 the network set-up time and network data rate are analysed and a hierarchical architecture for the distributed protocol is proposed and analysed. [ABSTRACT FROM AUTHOR]

A number of logical networks with differing traffic characteristics need to be generated over a distributed physical network in order to deal effectively with future call types and service configurations that involve a range of basic situations. Also, each call must examine one connectionless-type logical network by selecting the logical network that conforms to fundamental conditions based on the connection stipulations. The shortest route is selected through each switching node for each of the individual header data blocks (HB) of the call. The semi-shortest routing scheme that permits an increase in the number of relay stages is chosen, notably when a block occurs. Using this scheme, the HB loss probability between the originating and destination nodes is maintained reliably at about Nminld2 where the HB discard rates for each node are d equally and each originating and destination node is sufficiently distant from each other. Nmin is the minimum number of relay stages between the originating and destination nodes, l equals 2 in grid-type networks, and l equals 3 in honeycomb-type networks. The number of relays on the route between the originating and destination nodes can be a maximum of 2Nmin. The loss probability can increase by controlling the maximum number of relay stages. If the number of relays is limited to Nmin + 2, the reliable maximum value of the loss probability is approximately Nmind. The minimum reliable value of the loss probability is maintained at a level Nminld2. [ABSTRACT FROM AUTHOR]

This paper considers the primary distributed-type switching network which serves as the prototype for the distributed switching network. A method is shown to determine the route with the minimum number of tandem stages from the originator to the destination nodes in the network (called shortest route). The shortest route is given either by the straight path directly connecting the originator and the destination switching nodes, or, if such does not exist, by the following path. Consider the parallelogram that directly connects the originator and the destination switching nodes. Then the route is obtained from the originator switching node to the destination switching node by connecting arbitrarily the unit links on the border and the inside of the parallelogram, in the same direction as that of the edges of the parallelogram from the originator switching node to the destination switching node. The number of shortest routes between the originator and the destination switching nodes increases following the exponential function of the distance between the originator and the destination switching nodes. The number of tandem stages in the shortest route increases linearly with the distance. If a honeycomb-type network is employed, the number of tandem stages in the shortest mute can be reduced by approximately 15 percent at the maximum, compared to the grid-type network. When a failure such as blocking is produced between the originator and the destination, there exist three kinds of shortest mutes depending on the point of generation. [ABSTRACT FROM AUTHOR]

This paper presents the lower limit of loss probability in distributed communication networks and shows the limit of loss probability that can be obtained by logical networks based on the virtual networks to be used in the future. The paper analyzes the loss probability of high-quality traffic, whose volume is not large compared to non-copy simple-routing basic traffic. With this assumption, each node copies high-quality traffic data with header and sends it to multiple routes, through which the smallest number of transit switches are passed. On this condition, network topologies between originating and terminating nodes in the distributed network are simplified. The paper derives a methodology to give a loss probability in terms of a polynomial of the blocking rate d of each link. Based on this result, polynomials of d are given for each topology and numerical examples of loss probability are presented. © 1997 Scripta Technica, Inc. Electron Comm Jpn Pt 1, 80(11): 64–75, 1997 [ABSTRACT FROM AUTHOR]

We study the message complexity of the problem of distributively electing a leader in chordal rings. Such networks consist of a basic ring with additional links, the extreme cases being the oriented ring and the complete graph with a full sense of direction. We present a general election algorithm for these networks, and prove its optimality. As a corollary, we show that O(log n) chords at each processor suffice to obtain an algorithm that uses at most O( n) messages; this improves and extends a previous work, where an algorithm, also using O( n) messages, was suggested for the case where all n-1 chords exist (the oriented complete network). [ABSTRACT FROM AUTHOR]

Classes of network topologies are identified in which shortest-path information can be succinctly stored at the nodes, if they are assigned suitable names. The naming allows each edge at a node to be labeled with zero or more intervals of integers, representing all nodes reachable by a shortest path via that edge. Starting with the class of outerplanar networks, a natural hierarchy of networks is established, based on the number of intervals required. The outerplanar networks are shown to be precisely the networks requiring just one interval per edge. An optimal algorithm is given for determining the labels for edges in outerplanar networks. [ABSTRACT FROM AUTHOR]

The mobile wireless networks (MWNs) are flexible and scalable. They have been widely used in large-scale monitoring, search and rescue tasks, pursuit and escape operations and other scenarios. However, due to the high cost of wireless sensors in MWNs, the cost of increasing wireless sensor nodes is relatively high, so it is generally monitored by the limited nodes moving in the monitoring range. Having this in mind, we design an original algorithm to improve the monitoring efficiency of mobile wireless nodes, named Distributed Guidance Anti-flocking Algorithm (DGAA). Because most of the dynamic coverage algorithms are difficult to adapt to the complex operating environment. Furthermore the high overlapping rate of the wireless nodes is easy to cause resource waste. In light of these factors, the DGAA has a low overlapping rate of mobile wireless nodes in the complex environment with obstacles. DGAA mimics the predatory behavior of solitary animals. These animals can go out on their own to catch prey, and they do not leave their homes. At the same time, they can prevent the invasion of foreign individuals and ensure their maximum profits. The experiment is simulated on a map of 50m*50m, and the results are compared with those produced by competitive algorithms. Experimental results show that DGAA exhibits better performance than other algorithms. [ABSTRACT FROM AUTHOR]

The effectiveness of collaboration in distributed networks, such as sensor networks and multi-agent systems, relies on nodes' ability to exchange information. The availability of various communication protocols with different technical properties opens the possibility to guarantee connectivity during a system's operation in any condition. A communication network can be represented by a graph on which connectivity can be expressed by a well-known algebraic connectivity value or Fiedler value. It is one of the most important tools used in many applications where connectivity preservation is required. In this paper, a trust-based consensus algorithm for algebraic connectivity estimation has been implemented. To guarantee the accomplishment of the global objective and the system's performance, our contributions include: (i) a novel decentralized framework for combining multiple communication channels in a resulting channel and (ii) a decentralized algebraic connectivity control law that dynamically changes the number of agents in the system during operation. The proposed algebraic connectivity control strategy has been evaluated in simulations and in a real multi-robot system using two channels with different properties and initial topologies. [ABSTRACT FROM AUTHOR]

Wireless communication technology is spreading quickly in almost all the information technology areas as a consequence of a gradual enhancement in quality and security of the communication, together with a decrease in the related costs. This facilitates the development of relatively low-cost teams of autonomous (robotic) mobile units that cooperate to achieve a common goal. Providing real-time communication among the team units is highly desirable for guaranteeing a predictable behavior in those applications in which the robots have to operate autonomously in unstructured environments. This paper proposes a MAC protocol for wireless communication that supports dynamic resource reservation and topology management for relatively small networks of cooperative units (10–20 units). The protocol uses a slotted time-triggered medium access transmission control that is collision-free, even in the presence of hidden nodes. The transmissions are scheduled according to the earliest deadline first scheduling policy. An adequate admission control guarantees the timing constraints of the team communication requirements, including when new nodes dynamically join or leave the team. The paper describes the protocol focusing on the consensus procedure that supports coherent changes in the global system. We also introduce a distributed connectivity tracking mechanism that is used to detect network partition and absent or crashed nodes. Finally, a set of simulation results are shown that illustrate the effectiveness of the proposed approaches.

Due to technological advancement and deployment of handheld devices, mobile computing devices have gained the user attention to save resource usage, service access, and application use. In practice, it can be deployed widely to experience massive data storage and less computation cost. However, wireless channel access is vulnerable and insecure to prevent various potential attacks such as replay, redirection, etc. As a consequence, a seamless secure anonymous authentication scheme (S-SAAS) is proposed to create a secure session in cloud-based mobile edge computing. Since IoT, cloud computing, big-data and mobile technologies are converged to permit the group-based communication systems, it is highly demanded to strengthen the authentication process in order to reduce the security risk and vulnerabilities. Moreover, the experimental analysis proves that the proposed S-SAAS scheme consumes less signaling congestion and routing control overhead to achieve better service connection rate. [ABSTRACT FROM AUTHOR]

This paper demonstrates the feasibility of using a new complementary controlling structure for decreasing the in-series-equipment power loss. While keeping the main duties of a grid-tied inverter, unbalanced three phase loads are compensated using this complementary current controller feature. A high-pass filter is employed on both direct and quadrature axes in the common Park reference frame for this compensation. Besides discussing the unbalanced loading effects on the key issues such as in-series-equipment power loss, total harmonic distortion, human safety along with active and reactive power transferring ripple, a new controlling scheme is thoroughly introduced. MATLAB/Simulink and Power Station environments are used for simulating the steady state and dynamic behavior of a practical radial 24-bus distributed network equipped with a PV plant. The simulation results verify the effectiveness of the proposed controlling method. According to the case studies, 587 KWh energy saving has achieved in a 30 kW radial distributed network. [ABSTRACT FROM AUTHOR]

Distributed networks are networks in which each node can act as a server or client and hence any node can provide service to any other node. In such a scenario, establishing a trust model between the service providing user and the service utilizing user is a challenging task. At present, only a few approaches are available in the past literature to provide this facility. Moreover, the existing approaches do not provide high trust accuracy. Therefore,a novel efficient trust model has been proposed in this article to support the secure dynamic group communication in distributed networks. The main advantage of the proposed work is that it provides higher trust accuracy. Moreover, the proposed work takes less memory for maintaining the trust values and increases the packet delivery ratio in comparison with other existing works which are in the literature. [ABSTRACT FROM AUTHOR]

Liang, X.-B. and Wang, K., 2020. Ocean big data service technology in a distributed network environment. In: Gong, D.; Zhang, M., and Liu, R. (eds.), Advances in Coastal Research: Engineering, Industry, Economy, and Sustainable Development. Journal of Coastal Research, Special Issue No. 106, pp. 576–579. Coconut Creek (Florida), ISSN 0749-0208. Ocean big data is distributed, which has the characteristics of integrated application. In the distributed network environment, one must avoid information barriers, which will avoid the repeated construction of ocean big data service technology. Therefore, based on the construction of marine information infrastructure and demand orientation, the relationship between marine data sharing and information services can be demonstrated. Through the construction of the framework of ocean big data platform, this article develops ocean big data under the distributed network environment, which is very helpful for the application of ocean data. Through diversified ocean big data, this article establishes an efficient distributed computing ocean big data cloud platform, which is an important development direction of intelligent ocean construction. Through technical support, massive data resources can be used, which will tap the potential value of ocean data. [ABSTRACT FROM AUTHOR]

The commercial sector in Nigeria has been greatly hampered due to the poor availability of reliable electricity. In a 2014 World Bank report, nearly half of the firms doing business in Nigeria identified electricity as a major constraint, with over a quarter of them listing electricity as their biggest obstacle. The business losses due to electrical outages have been significant, with losses averaging about 16% of annual sales. The lack of access to reliable electricity is one of the biggest challenges to economic growth in Nigeria. This paper proposes a means of powering the commercial sector in Nigeria using urban swarm electrification. It outlines a conceptual framework for using a distributed network made up of grid-connected home solar PV systems as a viable option for providing the commercial sector with more reliable access to electricity. It further addresses the policy implications for the commercial sector with the enablement of more electrification options, implications that include strong economic impact, as well as the expansion and creation of new industries. [ABSTRACT FROM AUTHOR]