On Efficient Security Modelling of Complex Interconnected Communication Systems based on Markov Processes

Modeling and sensitivity analyses of VSP based virtual inertia controller in HVDC links of interconnected power systems

This article introduces a novel modular approach to the modelling of nonlinear interconnected complex systems. In the approach, a complex system is decomposed into self-contained easily identified modules to achieve easy linking of individual models. Our proposed approach to modelling differs from the traditional approaches in the following important aspects: (1) it is nonlinear, modular based, systematic, and graphical; (2) it is suitable for fault diagnosis; (3) depending on the level of complexity required, each module may be changed separately quite easily without having to change the other modules; and (4) it draws from the powerful capabilities of the widely used packages of Simulinkand Matlab. These features provide for a generic package that can simulate a complex interconnected system of any description and configuration, as well as simulating any kind of fault anywhere in the system by merely changing the input vector. Examples of two power systems are used as case studies, where it is shown that complex systems can be constructed and simulated easily by appropriately combining components together. The simulation studies show the dynamical behaviour of the two systems with and without faults being applied to them.

This article introduces a novel modular approach to the modelling of nonlinear interconnected complex systems. In the approach, a complex system is decomposed into self-contained easily identified modules to achieve easy linking of individual models. Our proposed approach to modelling differs from the traditional approaches in the following important aspects: (1) it is nonlinear, modular based, systematic, and graphical; (2) it is suitable for fault diagnosis; (3) depending on the level of complexity required, each module may be changed separately quite easily without having to change the other modules; and (4) it draws from the powerful capabilities of the widely used packages of SimulinkTM and MatlabTM . These features provide for a generic package that can simulate a complex interconnected system of any description and configuration, as well as simulating any kind of fault anywhere in the system by merely changing the input vector. Examples of two power systems are used as case studies, where it is shown that complex systems can be constructed and simulated easily by appropriately combining components together. The simulation studies show the dynamical behaviour of the two systems with and without faults being applied to them.

Efficient modeling and optimizing of checkpointing in concurrent component-based software systems

The background of the development of the model of economic development of Ukraine in the context of social orientation has been analyzed taking into account the interdependent influence of the mechanism of market relations and economic policy of the state. It is researched that the economic mechanism of socially oriented market economy contains organizational structure of production (vertical and horizontal), specific forms of functioning of economic system (state and non-state regulation of the market), as well as a specific institutional base (including its legislative component). The constituents of the economic system are entities formed by large economic entities (eg financial corporations). The authors argue that the economic mechanism of a socially oriented national economy is a complex structure and system of interconnections and includes: a) a system of balanced markets; b) public sector of economy; c) large economic structures that fulfill the regulatory role of the state for the economy as a whole and at the same time increase the market sensitivity to medium and long-term programs of its development; d) public sector administrative and production subsystem; e) system of operative state regulation of economy; e) a budget-balancing system with a powerful core; g) regulatory framework governing mid-market processes. The study states that Ukraine, in rather difficult conditions, produces the parameters of its own national model of socio-economic development for the long term. The country has not yet formulated or implemented an effective model of economic development that would fully reflect its national characteristics and interests and become a macroeconomic basis for effective state regulation It is determined that in the conditions of construction of a new model of the national economy the role of non-governmental and charitable organizations is increasing. The role of non-governmental organizations, which represent one of the most optimal legal forms to assist citizens in solving their common problems, upholding common interests, is a compulsory attribute of the model of socially oriented national economy.

PurposeThe purpose of this paper is to design an open architecture of an interconnected communication system (ICS) for multi‐level electric power control centers (EPCC) based on Tele‐control Application Service Element (TASE.2), which possesses specialties of high performances, robustness, cost‐efficiency, quick‐restoration, and easy‐maintenance.Design/methodology/approachBased on the hierarchy and structure of TASE.2, the overall architecture of the ICS for multi‐level EPCC is put forward at first. As the key devices in the system, the structures of the communication gateway (CG) and common interface are designed. Then, the logical procession flows in CG and the con modes, for both CG and IC are analyzed in detail. The web‐based software configuration of remote maintenance and fault diagnosis is discussed conceptually.FindingsAs a standardized, well‐developed, and efficient protocol, TASE.2 is considered to be the most suitable protocol to support the ICS for multi‐level EPCC.Research limitations/implicationsThe performance of the ICS needs to be further simulated.Practical implicationsPractical architecture for ICS for multi‐level EPCC with robustness and cost‐efficient specialty is designed in principle, which is very useful for manufacturers to develop pilot devices or even products.Originality/valueThis paper proposes a new ICS scheme for multi‐level EPCC based on TASE.2 is proposed.

A large-scale renewable electricity supply system by 2030: Solar, wind, energy efficiency, storage and inertia for the South West Interconnected System (SWIS) in Western Australia

Traditionally most services have used several independently operating specially developed communications networks to carry their specific message and traffic types. They have been labour intensive requiring operator assistance when transferring messages across different communication systems. Communication systems currently being deployed are fully automated, thus in principle enabling communication networks to be interconnected and passing messages without operator intervention. However, the message formats being used need to be (at least partly) recognised by each communication system for it to be possible to forward it to the intended recipient in the right manner. Also the traffic capacity differs between interconnected communication systems operating in different frequency bands. There is therefore a need to optimise the throughput between each involved communication system thus making it possible to reduce the signalling overhead on each link. This paper describes how Internet related services, such as email forwarding, have been implemented through specially developed proxies in order to make the best possible use of the embedded features in two different HF systems, KV 90 and Mil-Std-188-141A ALE.

Complex, highly interconnected acoustic systems can be difficult to model for students and inexperience practitioners. The systematic lumped-element circuit model construction method presented here is easy to learn and teach, and allows for rapid, error-free circuit model construction. The present author discovered the method in a book by Mario Rossi [Acoustics and Electroacoustics, Artech House Publishers (1988)] and has included it in the electroacoustic transducers course taught at the University of Texas at Austin since 2003. This method has been effective in this course and utilizes two types of effective instruction discussed in the scientific education literature: the use of interactive engagement and visual models.

The Food and Agriculture Organization of the United Nations (FAO) estimates that food production must be increased 70% (from 2009 levels) in order to feed an additional 2.3 billion people by 2050 (FAO 2009). Irrigated cropland is extremely important to global food security. According to FAO (2009), although irrigated cropland currently occupies only about 20% of the total agricultural area worldwide, it supplies roughly 40% of the total yield (i.e. 3.6 times that of dryland). Groundwater is an extremely important source of irrigation water. An estimated 38% of irrigated areas depend on groundwater (Siebert et al. 2010) and in the U.S., groundwater supplies 43% of the irrigation water (Maupin et al. 2014). At the same time, an increasing number of countries and regions are reaching alarming levels of water scarcity. According to NASA satellite data, 13 of the largest 37 aquifers in the world are considered significantly distressed (Richey et al. 2015). Severe aquifer depletion evident in the Ogallala Aquifer, California’s Central Valley, the Mississippi Delta, and Arizona’s alluvial basins (Konikow 2013) threaten food production in the U.S. How will we meet growing food demands and the water needs of growing populations in these regions with declining aquifers? How do we prolong, sustain, or restore these aquifers? When restoration is not possible, how do we best support the conversion to dryland or grazing systems? This JCWRE special issue examines new technologies, cropping system management practices, decision support tools, incentives and policies to sustain food production, rural communities, and ecosystem services in these critical regions. In particular, recent research advances from the decades long USDA-ARS funded Ogallala Aquifer Program, recently funded USDA-NIFA Ogallala Water Coordinated Agricultural Project, and regional efforts in California and the Mississippi Delta are discussed. Brauer et al. describe the research and education efforts of the Ogallala Aquifer Program conducted over the last decade and a half. USDA-ARS laboratories in Bushland and Lubbock TX, with university partners at Kansas State University, Texas A&M AgriLife Research and Extension Service, Texas Tech University and West Texas A&M University are developing and evaluating water management strategies and technologies to reduce water withdrawals for irrigation by 20% in 2020 (compared to 2012) and increase the productivity and profitability of dryland cropping systems, including developing best management practices for production of high value and alternative crops for both dryland and irrigated systems. This consortium is also working to improve the understanding of hydrological and climatic factors affecting water use and agricultural profitability and determining the impacts of alternative water withdrawal/use policies on the economic viability of the agriculture industry of the Southern Ogallala Aquifer region. These efforts are extremely important, particularly with the warming trends documented by Lin et al. resulting in increased evapotranspiration loss, soil moisture stress, and associated management challenges in Kansas. This, coupled with declining water levels in the Ogallala Aquifer and increasing restrictions on pumping are challenging the production of corn and other crops. Xue et al. found in their review of long-term production and corn management practices that yields and water use efficiency have increased due to advances in corn genetics and irrigation technologies, and recommended continued research to improve grain quality, crop drought tolerance, and adoption of new technologies to sustain production in the High Plains. Water use-yield relationships are important for efficient water management (Siahpoosh et al. 2012) and models such as the Kansas Water Budget (KSWB) and Decision Support System for Agrotechnology Transfer (DSSAT) Cropping System Model (CSM) are important tools to assess these relationships. Moberly et al. evaluated the predictive accuracy of the KSWB model for crop water use and grain sorghum and winter wheat productivity, grown in a range of crop sequences. They found that the Kansas Water Budget model provided a useful analytic framework for predicting water supply constraints to grain production, but poorly predicted yield response for either grain sorghum or winter wheat. Adhikari et al. used the DSSAT-CSM model to simulate the long term cotton lint yield and seasonal crop ET and found it useful for scheduling ET-based irrigation management practices in the Texas High Plains and estimating future ET for other modeling experiments. In addition to these models, groundwater models that not only capture regional hydrogeologic characteristics but also human-hydrologic-climate interactions are crucial for guiding future water management and policy planning endeavors. A conceptual modeling framework built on this premise was applied by Uddameri et al. to a current regional-scale groundwater modeling study in the Southern High Plains where the lack of groundwater production data is a major limiting factor. To identify alternative approaches to fill this critical data gap and properly parameterize the model, they evaluate the importance of surface water groundwater interactions, determine whether explicit coupling of watershed and groundwater models is warranted, and assess limitations in simulating human-aquifer interactions. The study demonstrated the utility of several simple “first-cut” analysis techniques to evaluate groundwater interactions with other interconnected systems. Golden and Guerrero evaluate the likely economic impacts associated with the implementation of LEMAs, Local Enhanced Management Areas authorized by the 2012 Kansas Legislature. Under this Kansas water law, groundwater management districts have the authority to initiate a voluntary process to develop a conservation plan meeting local goals. Results suggest that the LEMA framework of groundwater management will provide benefits to both the agricultural producer and rural communities. However, Golden and Guerrero note that LEMA adoption may only result in short-lived reductions in groundwater consumption with water saved today eventually being used and the water resource exhausted. Similarly, in 2014, the Sustainable Groundwater Management Act was enacted in California to reform groundwater management and ensure groundwater is managed sustainably. To help groundwater managers create some of the baseline measures needed to develop a groundwater sustainability plan required by this Act for medium and high priority basins, Flores Marquez et al. introduce a novel method for development of a water budget and present the implementation of this method in the Ukiah Valley Groundwater Basin. Results indicate that because the groundwater basin is not experiencing a decrease in groundwater storage or a lowering of the water table, the groundwater sustainability agency is uniquely positioned to focus on proactive maintenance of current conditions when constructing their sustainability plan. In the final paper, Reba et al. describe key research efforts in the Lower Mississippi River Basin, an internationally-important region of intensive crop production heavily reliant on the Mississippi River Valley Alluvial Aquifer for irrigation. This region too is facing aquifer depletion and exploring innovative methods to address this issue. Reba et al. investigated innovations in rice irrigation, on-farm water storage, and managed aquifer recharge as means to reduce the on-going decline of this economically and ecologically important alluvial aquifer. They found that collaborative efforts to improve rice irrigation management as part of the Rice Stewardship Partnership effectively reduced the amount of water applied on nearly 30,000 hectares. Their inventory of on-farm reservoir tailwater recovery systems showed that significant investments have been made as part of efforts and supports the potential for surface water storage in critical groundwater areas. Finally, the novel test of managed aquifer recharge described will be used as the basis for further testing in areas where large-scale surface water projects are unlikely. As this special issue demonstrates, significant efforts and advances are ongoing throughout the U.S. and globe to ensure food and water needs are met into the future. However, continued research is needed to improve irrigation efficiency, crop genetics, cropping systems, and our understanding of the climate, hydrology, water use, and policy impacts. As noted by Golden and Guerrero, adoption may only result in short-lived reductions in groundwater consumption with water saved today eventually being used and production ultimately converted to dryland. Efforts today to improve dryland production will go a long way to ensuring food for future generations. Kevin L. Wagner is the Director of the Oklahoma Water Resources Center and holds the Thomas E. Berry Professorship in Integrated Water Research and Management. He provides leadership and administration of the Center’s water programs, leads Center efforts to increase engagement with the water resources community across Oklahoma and the nation, and facilitates development of inter-disciplinary teams to address high priority water resources issues. Wagner has more than 20 years of experience in watershed assessment and planning, stakeholder engagement and conservation practice research and education. He may be contacted at [email protected].

Mexico is committed to reducing its CO2 emissions according to the Paris Agreement. A relevant effort must be made for the analysis of Mexico's electric energy system towards a progressive decarbonization with a larger participation of intermittent renewable energies. The analysis of power planning scenarios, with different assumptions on costs, emissions, and intermittent performance of the power generating technologies, is needed to make sustainable decisions in the transition toward a cleaner power sector. Tools for energy modelling are required to develop and analyze scenarios with minimum costs subject to environmental constraints. The purpose of the article is to explain the modelling approach of a novel and flexible power planning tool, which is based on a well‐known linear programming optimization method combined with a computing strategy to optimize time consumed for reading, processing calculations, and writing the huge number of economic and technical parameters required for the hourly power dispatch in complex interconnected electric systems. The time consumed has been optimized by means of a binary matrix that activates the input and use of only the data needed for the solution of the problem. The paper describes the MC model and demonstrates some of its analytical capabilities through a Mexican case study with a least cost scenario and two decarbonization scenarios of the power interconnected system for the period from 2020‐2050.

In an interconnected power system network, global performance is affected by various unknown power system parameters subjected to system uncertainties. These unknown parameters in the control expression deteriorate the performance of the power system network. Therefore, these terms associated with the control expression must be estimated precisely. This paper proposes an adaptive backstepping scheme using an entirely coupled recurrent neural network (ECRNN) to estimate these control terms. Three continuous differentiable functions are used to design control input, virtual signals, and adaptive control laws to achieve global performance. The objective of ECRNN is to reduce the control complexity by estimating the associated nonlinear term in the control expression. It will facilitate the complex formulation of the controller and improve system performance. The robust functional estimation ability of ECRNN will make the system immune to uncertainties that may appear due to external disturbances. In ECRNN, feedback loops are added to each neuron layer to achieve additional estimation accuracy. The proposed adaptive law enhances the online weight update speed and accuracy. Verification of the proposed scheme is carried out in MATLAB/Simulink. It is also verified in the real-time digital simulator (RTDS) platform using the IEEE standard New England 39-bus, 10-machine power system model. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —This paper is motivated by the existing limitations in the global performance of a multimachine power system network due to uncertainty in the system parameters. Uncertainties in the power system network primarily appeared due to penetration of renewable power sources, load uncertainty, or occurrence of an uncertain fault in the network. As power system networks are complex nonlinear interconnected systems, these perturbations in the generator states may cause economic losses, load demand uncertainty, or electric scarcity. Thus, a control scheme is required to address the global performance of such networks. This article proposes uniform ultimate bounded stability of synchronous generators in a multimachine power system network with a robust ECRNN-based backstepping control design. The other available technique has not adequately addressed the global performance under uncertainties. The efficacy of the proposed scheme is verified in a real-time environment via a real-time digital simulator which may be a feasible solution for designing excitation control for the synchronous machine in an extensive industrial network.

Connectomics: A new paradigm for understanding brain disease

This paper deals with a MultiAgent System (MAS) and our primary objective is to study how the behavior of the system changes when the interconnections among the agents exhibit non-uniform link weights. Our main contribution is to show when the system with non-uniform coupling strengths is more stable compared to the system with uniform weights. In the process of proving our main idea, we tackle the stability of the system and we propose an approximation method for the computation of the system convergence time.

In this paper, a framework incorporating flexibility as a characteristic is proposed for designing complex, resilient socio-ecological systems. In an interconnected complex system, flexibility allows prompt deployment of resources where they are needed and is crucial for both innovation and robustness. A comparative analysis of flexible manufacturing systems, economics, evolutionary biology, and supply chain management is conducted to identify the most important characteristics of flexibility. Evolutionary biology emphasises overlapping functions and multi-functionality, which allow a system with structurally different elements to perform the same function, enhancing resilience. In economics, marginal cost and marginal expected profit are factors that are considered to be important in incorporating flexibility while making changes to the system. In flexible manufacturing systems, the size of choice sets is important in creating flexibility, as initial actions preserve more options for future actions that will enhance resilience. Given the dynamic nature of flexibility, identifying the characteristics that can lead to flexibility will introduce a crucial dimension to designing resilient and sustainable socio-ecological systems with a long-term perspective in mind.