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This column surveys selected papers in computational sustainability from the 30th AAAI Conference on Artificial Intelligence. [ABSTRACT FROM PUBLISHER]

The Research Resource Identifier (RRID) was introduced in 2014 to better identify biomedical research resources and track their use across the literature, including key digital resources such as databases and software. Authors include an RRID after the first mention of any resource used. Here, we provide an overview of RRIDs and analyze their use for digital resource identification. We quantitatively compare the output of our RRID curation workflow with the outputs of automated text mining systems used to identify resource mentions in text. The results show that authors follow RRID reporting guidelines well, and that our natural language processing based text mining was able to identify nearly all of the resources identified by RRIDs as well as thousands more. Finally, we demonstrate how RRIDs and text mining can complement each other to provide a scalable solution to digital resource citation. [ABSTRACT FROM AUTHOR]

This paper focuses on developing an appropriate combinatorial optimization technique for solving the optimal sizing problem of hybrid ac–dc microgrids. A novel two-stage iterative approach is proposed. In the first stage, a meta-heuristic technique based on a tailor-made genetic algorithm is used to tackle the optimal sizing problem, while, in the second, a non-linear solver is deployed to solve the operational problem subject to the obtained design/investment decisions. The proposed approach, being able to capture technical characteristics such as voltage and frequency through a detailed power flow algorithm, provides accurate solutions and, therefore, can address operational challenges of microgrids. Its capability to additionally capture contingencies ensures that the proposed sizing solutions are suitable both during normal operation and transient states. Finally, the genetic algorithm provides convergence of the model with relative computational simplicity. The proposed model is applied to a generalizable microgrid comprising of ac and dc generators and loads, as well as various types of storage technologies in order to demonstrate the benefits. The load and natural resources data correspond to real data. [ABSTRACT FROM AUTHOR]

Conventionally, power flow equations are used for distribution systems (DS) analysis to find the nodal voltages. For the particular form of the DS reconfiguration problem, however, a direct formulation in terms of branch flows allows a substantial increase in solution efficiency from an optimization point of view. In this paper, a set of linear current flow (LCF) equations are derived for DS. This formulation is then used within the network reconfiguration problem for loss minimization. A mixed-integer quadratically constrained programming (MIQCP) formulation, together with a mixed-integer linear programming (MILP) formulation, are proposed in this paper and assessed through simulations. In these comparisons, the MILP formulation shows computational advantages over the MIQCP version and the preceding literature. The proposed methods are evaluated on several test systems. [ABSTRACT FROM PUBLISHER]

This paper addresses the self scheduling problem of a price-taker power producer. It focuses on risk modeling, emphasizing the tradeoff existing between maximum profit and minimum risk. The paper analyzes a self-scheduling model that considers simultaneously profit and risk. This model Is formulated as a mixed-Integer quadratic programming problem, which Is solved using commercially available software. Relevant results from a realistic case study are discussed. [ABSTRACT FROM AUTHOR]

Fast frequency response (FFR) is an option in maintaining system security under low inertia conditions. Power electronics interfaced energy resources such as wind and photovoltaics have the capability to deliver FFR. At present, almost all installed power electronics interfaced energy resources are connected to the grid by the phase locked loop (PLL)-synchronized voltage source converter (VSC) and they usually implement inertial response by measuring the rate of change of frequency (RoCoF). However, RoCoF measurements are highly susceptible to disturbances in the grid. In this paper, a novel inertia controller is developed for PLL-synchronized VSC interfaced energy resources to implement natural inertial response without measuring RoCoF. A thorough stability analysis is performed to study the impact of proposed inertia controller on the VSC in weak grid. The proposed inertia controller makes the deviation of DC voltage proportional to the deviation of system frequency. Further, a method of primary frequency control is proposed by measuring DC voltage rather than grid frequency. The proposed FFR scheme of inertia and primary frequency control is applied to a direct-drive windfarm connected to a grid, and its correctness and advantages are verified by simulation. [ABSTRACT FROM AUTHOR]

Linear power flow models are widely used in power systems to simplify the nonlinear power flow equations. The DC power flow model is one of the representatives. There are many other linear power flow models that improve the DC power flow model with the inclusion of $\boldsymbol{Q}$ and $\boldsymbol{v}$. However, existing linear models are derived based on empirical mathematical approximation without a general methodology guidance. In this paper, we found that the fundamental difference among different linear power flow models lies in the formulation of “independent variables.” Based on this finding, a general formulation of linear power flow models is proposed. The linearization error is theoretically analyzed. In particular, the case when $\boldsymbol{ \theta }$ and $\boldsymbol{v^{\scriptscriptstyle k}}$ are regarded as independent variables is thoroughly investigated. Method for finding the linear power flow with the minimum error is presented. The formulation of the independent variables associated with the minimum linearization error is determined by the distribution of state variables $\boldsymbol{v}$ and $\boldsymbol{\theta }$. It is shown that the linearization error when $\boldsymbol{v^{\scriptscriptstyle 2}}$ is regarded as an independent variable is normally smaller than that for $\boldsymbol{v}$ because of the special properties of the distribution of $\boldsymbol{v}$ in power grids. [ABSTRACT FROM AUTHOR]

As intermittent energy resources become more significant in power production, traditional capacity planning may be insufficient to ensure reliable system operation. A system planner must ensure that flexibility solutions are available to respond to large and uncertain ramping events. These solutions may be operational, such as improved unit commitment and dispatch, curtailment of renewables, or demand response; procurement based, such as new fast ramping resources or batteries; or involve market reform. This paper outlines a new methodology for modeling the economic tradeoffs in implementing flexibility solutions for integrating renewables. The proposed model includes both a stochastic treatment of system states to account for a wide range of operating conditions and an adapted production simulation methodology that weighs the cost of reliability and subhourly flexibility violations against the cost of the operational flexibility solutions available to mitigate them. The model's functionality is demonstrated with a case study of California at a 50% RPS in 2030. The model tests the value of 1088 MW of generic flexible units, relative to the same capacity of must-run resources, finding an expected annual value of \$347\pm 42 million/yr. Potential applications of the model for resource planning and procurement are also discussed. [ABSTRACT FROM PUBLISHER]

Fuel cell (FC) is emerging as a clean and nonpollutant energy source and is being used widely in most of the transport and microgrid applications. However, certain applications demanding fast dynamic response are restricting usage of FC on account of its lifetime issues. Slow dynamic response of FC is not suitable to provide transient load demands, typically arising in electrical vehicles during acceleration and in braking. This paper presents a novel control strategy and associated power electronics for such applications. We propose a Lure–Lyapunov-based controller executed in cascade mode for the control of hybrid energy management system of FC and ultracapacitor (UC). In the proposed scheme, UC responds to transients in load demand whereas FC takes care of the nominal load bus requirements. This combination helps in improving lifetime of FC as auxiliary storage device such as UC provides a cushion for sudden transients. The proposed control strategy also helps in maintaining state of charge of UC for better performance. The inherent nonlinearities in DC–DC converter are efficiently handled by the outer-loop Lure–Lyapunov framework. Mathematical modeling and a proof for absolute stability of the system is presented. The proposed controller strategy is robust by virtue of being passivity based control methodology. The paper also presents analysis of the required power electronics involving DC–DC converters and inner-loop current control action. The synthesized controller is experimentally validated and the results are presented with their analysis. [ABSTRACT FROM PUBLISHER]

This paper tackles the problem of dynamic power management (DPM) in nanoscale CMOS design technologies that are typically affected by increasing levels of process and temperature variations and fluctuations due to the randomness in the behavior of silicon structure. This uncertainty undermines the accuracy and effectiveness of traditional DPM approaches. This paper presents a stochastic framework to improve the accuracy of decision making during dynamic power management, while considering manufacturing process and/or environment induced uncertainties. More precisely, variability and uncertainty at the system level are captured by a partially observable semi-Markov decision process with interval-based definition of states while the policy optimization problem is formulated as a mathematical program based on this model. Experimental results with a RISC processor in 65-nm technology demonstrate the effectiveness of the technique and show that the proposed uncertainty-aware power management technique ensures system-wide energy savings under statistical circuit parameter variations. [ABSTRACT FROM AUTHOR]

In this paper, we propose a novel nonlinear approach to solve the short-term hydro scheduling problem under deregulation, considering head-dependency. The actual size of hydro systems, the continuous reservoir dynamics and constraints, the hydraulic coupling of cascaded hydro systems, and the complexity associated with head-sensitive hydroelectric power generation still pose a real challenge to the modelers. These concerns are all accounted for in our approach. Results from a case study based on one of the main Portuguese cascaded hydro systems are presented, showing that the proposed nonlinear approach is proficient. [ABSTRACT FROM AUTHOR]

This paper introduces orthogonal decision trees that offer an effective way to construct a redundancy-free, accurate, and meaningful representation of large decision-tree-ensembles often created by popular techniques such as Bagging, Boosting, Random Forests, and many distributed and data stream mining algorithms. Orthogonal decision trees are functionally orthogonal to each other and they correspond to the principal components of the underlying function space. This paper offers a technique to construct such trees based on the Fourier transformation of decision trees and eigen-analysis of the ensemble in the Fourier representation. It offers experimental results to document the performance of orthogonal trees on the grounds of accuracy and model complexity. [ABSTRACT FROM AUTHOR]

A hybrid power system consists of a combination of two or more power generation technologies to make best use of their operating characteristics and to obtain efficiencies higher than that could be obtained from a single power source. Since fuel cells directly convert fuel and an oxidant into electricity through an electrochemical process, they produce very low emissions and have higher operating efficiencies. Hence, combining fuel cells with other sources, the efficiency of the combined system can be further increased or extend the duration of the available power to the load as a backup power. In this paper, different types of fuel-cell hybrid systems and their applications are presented. An analysis of the combined cycle operation of a solid oxide fuel cell (SOFC)-microturbine is presented. A strategy for combining the thermophotovoltaic power generation unit and SOFC to obtain the hybrid power system that would have higher efficiency is proposed. The hybrid operation of wind power and solar power system with proton exchange membrane fuel cell is also presented. [ABSTRACT FROM AUTHOR]

Cognitive radio is viewed as a novel approach for improving the utilization of a precious natural resource: the radio electromagnetic spectrum. The cognitive radio, built on a software-defined radio, is defined as an intelligent wireless communication system that is aware of its environment and uses the methodology of understanding-by-building to learn from the environment and adapt to statistical variations in the input stimuli, with two primary objectives in mind: • highly reliable communication whenever and wherever needed; • efficient utilization of the radio spectrum. Following the discussion of interference temperature as a new metric for the quantification and management of interference, the paper addresses three fundamental cognitive tasks. 1) Radio-scene analysis. 2) Channel-state estimation and predictive modeling. 3) Transmit-power control and dynamic spectrum management. This paper also discusses the emergent behavior of cognitive radio. [ABSTRACT FROM AUTHOR]

A low-cost high-frequency power supply for ozone generation is presented in this paper. The paper addresses two important issues. Firstly, the ozone reactor is tested at high frequency and a new model of this type of load is proposed. Secondly, the power supply stage is presented and analyzed, obtaining some important characteristics that allow the correct design of this power converter. Simulation and experimental results are also provided to evaluate the possibilities of the proposed converter. [ABSTRACT FROM AUTHOR]

In this paper, control system designs are proposed for the Broken River in Victoria, Australia. The aim of the control system is to improve water resource management and operation for the benefit of irrigators and the environment. Both centralized and decentralized control schemes are considered. The decentralized scheme consists of a number of PI and I controllers, while the centralized scheme is a model predictive controller. The controllers are designed based on simple models obtained using system identification methods. In a realistic simulation scenario, the control systems compared very favorably with current manual operation offering increased operational flexibility with a significant potential for substantial water savings, improved level of service to irrigators, and improved environmental benefits. [ABSTRACT FROM AUTHOR]

Recent X-band SAR missions, such as COSMO-SkyMed (CSK), which is able to provide very high spatial resolution images of an area of interest with a short revisit time, are expected to be quite useful sources of information for monitoring the terrestrial environment and its changes. On the other hand, the huge amount of data involved, as well as the need to promptly act in case of emergency, requires the development of automatic change detection tools. This paper reports on a novel automatic change detection algorithm combining multilayer perceptron neural networks (NNs) and pulse coupled NNs, which has been implemented and tested on pairs of Stripmap and Spotlight CSK images acquired on the Tor Vergata University area in the southeast outskirts of Rome, Italy, where a significant and continuous urbanization process is occurring. [ABSTRACT FROM PUBLISHER]

Because of a concern that in developing transitional energy systems the endpoint system requirements should be kept in mind, this paper focuses on storage in a renewable energy system that uses no fossil fuels. Based largely on the current seasonal patterns of consumption and wind and solar energy generated, it is estimated that the energy storage capacity that would be required to supply the electrical energy for the United States for a year given that the source of the electricity is from solar, wind, or a combination of the two, is in the order of 10%–20% of the total annual demand. While the uncertainty within and between published estimates of biomass availability is quite large, a partial review of the literature indicates that the global biomass primary energy potential could satisfy seasonal energy demands in a sustainable manner. The storage volumes required for biomass and hydrogen, another storage possibility, to meet seasonal storage needs are considerably smaller than that required for compressed air or elevated water. [ABSTRACT FROM PUBLISHER]

Technology scaling has entered a new era, where chip performance is constrained by power dissipation. Power limits vary with the application domain; however, they dictate the choices of technology and architecture and necessitate implementation techniques that tradeoff performance for power savings. This paper examines technology options in the power-limited-scaling regime and reviews sensitivity-based analysis that can be used for the optimal selection of optimal architectures and circuit implementations to achieve the best performance under power constraints. These tradeoffs are examined in the context of power minimization at the technology, circuit, logic, and architecture levels, both at the design and run times. [ABSTRACT FROM AUTHOR]

A cost optimization scheme for a microgrid is presented. Prior to the optimization of the microgrid itself, several schemes for sharing power between two generators are compared. The minimization of fuel use in a microgrid with a variety of power sources is then discussed. The optimization of a small power system has important differences from the case of a large system and its traditional economic dispatch problem. Among the most important differences is the presence of a local heat demand which adds another dimension to the optimization problem. The microgrid considered in this paper consists of two reciprocating gas engines, a combined heat and power plant, a photovoltaic array and a wind generator. The optimization is aimed at reducing the fuel consumption rate of the system while constraining it to fulfil the local energy demand (both electrical and thermal) and provide a certain minimum reserve power. A penalty is applied for any heat produced in excess of demand. The solution of the optimization problem strongly supports the idea of having a communication infrastructure operating between the power sources. [ABSTRACT FROM AUTHOR]

The images of the atmospheric-pressure glow discharges driven by the radio-frequency power supply using He, Ar, N2, O2, air, or their mixture as the primary plasma-working gas are presented in this paper. The plasma jet, produced using the planar-type plasma generator behaving like a "brush", is useful for the effective treatment of different materials exposed to the plasma jet. [ABSTRACT FROM AUTHOR]

Next generation cellular networks (5G) have to deal with massive deployment of machine-type-communication (MTC) devices, expected to cause congestion and system overload in both the radio access network (RAN) and the core network (CN). Moreover, not only would the network suffer from the system overload, but also the MTC devices would experience high latency to access the channel and high power consumption due to the retransmission attempts. Indeed, power consumption is a critical issue in MTC, as the devices are not plugged into the electrical supply, e.g., in the case of sensor devices. To alleviate system overload (caused by the massive MTC deployment), the 3GPP proposed the group paging (GP) method. However, its performances dramatically decrease when increasing the number of MTC devices being paged. In this paper, we devise a novel method, named further improvement-traffic scattering for group paging (FI-TSFGP), which aims to improve the performance of GP when the number of MTC devices is high. FI-TSFGP scatters the paging operation of the MTC devices over a GP interval instead of letting all of the devices start the channel access procedure at nearly the same time. By doing so, FI-TSFGP achieves high-channel access probability for MTC devices, leading to the reduction of both the channel access latency and power consumption. Compared to GP and two other schemes, simulation results clearly demonstrate the high performance of FI-TSFGP in terms of: success and collision probabilities, average access delay, average number of preamble transmissions, and ultimately energy conservation. [ABSTRACT FROM AUTHOR]

In this paper, the benefits of distributed energy resources are considered in an energy management scheme for a smart community consisting of a large number of residential units (RUs) and a shared facility controller (SFC). A noncooperative Stackelberg game between the RUs and the SFC is proposed in order to explore how both entities can benefit, in terms of achieved utility and minimizing total cost respectively, from their energy trading with each other and the grid. From the properties of the game, it is shown that the maximum benefit to the SFC, in terms of reduction in total cost, is obtained at the unique and strategy-proof Stackelberg equilibrium (SE). It is further shown that the SE is guaranteed to be reached by the SFC and RUs by executing the proposed algorithm in a distributed fashion, where participating RUs comply with their best strategies in response to the action chosen by the SFC. In addition, a charging–discharging scheme is introduced for the SFC's storage device that can further lower the SFC's total cost if the proposed game is implemented. Numerical experiments confirm the effectiveness of the proposed scheme. [ABSTRACT FROM PUBLISHER]

Highly sensitive and selective functional nanobiobreaksensors are being developed because they have significant applications in the sustenance and conservation of natural resources and can be used in projects to identify degraded and contaminated areas (of both soil and water) and as environmental quality indicators. In the present study, a nanobiosensor was developed based on using theoretical models (molecular docking and molecular dynamics simulations) based on biomimicry of the action mechanism of herbicides in plants coupled with atomic force microscopy (AFM) tools. The herbicide molecules were detected at very low concentrations using a unique sensor construction: the AFM probes and the substrate were chemically functionalized to favor covalent bonding and promote molecular flexibility, as well as to achieve reproducible and accurate results. Computational methods were used to determine the binding energies associated with the enzyme-herbicide interactions, which were compared with experimental results for adhesion forces. The theoretical results showed that the diclofop herbicide could be assembled and attached onto the mica substrate surface and the ACCase enzyme on the AFM probe without damaging the diclofop molecule. The experimental results showed that using a specific agrochemical target molecule was more efficient than using other nonspecific agrochemicals. On average, there was a 90% difference between the values of specific recognition (diclofop) and nonspecific recognition (imazaquin, metsulfuron, and glyphosate). This result validated the selectivity and specificity of the nanobiosensor. The first evidence of diclofop detection by the AFM probe sensors has been presented in this paper. [ABSTRACT FROM PUBLISHER]

Underground mining easily causes casualties, and illegal mining is a major contributor to this issue. It is a challenge to locate and differentiate illegal mines from approved mines over a vast area. Over the past few years, our research in satellite differential radar interferometry (DInSAR) to monitor underground-mine-induced surface subsidence has demonstrated the reliability of DInSAR. In this paper, a DInSAR-based illegal-mining detection system (DIMDS) is proposed to exploit the geometric, spatial, and temporal characteristics of those subsidence patterns. Testing results over a coalfield in Asia have proven the efficiency, reliability, and cost effectiveness of DIMDS in finding out illegal mines. [ABSTRACT FROM PUBLISHER]

Small- and medium-sized distributed generation (DG) systems in a microgrid normally have inverters, and the inverter outputs are connected to the grid through an LCL filter. In this paper, we are interested in designing a DG inverter that behaves like a uninterruptible power supply (UPS) for its dedicated loads, while enabling power flow control with the microgrid. If the grid power is lost, then the DG system can be transferred smoothly to the island (stand-alone) operation. This islanding capability provides a higher reliability of the local ac bus than the conventional power system. In order to have such a UPS functionality, the inverter is desired to have a high control bandwidth, which is required for regulating the AC bus voltage at the presence of nonlinearities and unpredictable behaviors of the loads. As for a fast controller, a two-degree-of-freedom (DOF) controller is applied to the LC filter plant with the inverse dynamic model. The voltage command levels are selected considering the amount of power share with the grid. The effectiveness of the proposed control scheme is shown by experimental results. [ABSTRACT FROM AUTHOR]

As wind power penetrations increase in isolated power systems, more innovative and sophisticated approaches to system operation will need to be adopted due to the intermittency and unpredictability of wind power generation. In this paper, a hybrid approach of combining branch and bound algorithm with a dynamic programming algorithm is developed to coordinate the wind and thermal generation scheduling problem for operating an isolated hybrid power system reliably and efficiently. Several technique constraints are applied to determine the maximum proportion of wind generator capacity that can be integrated into the system. A simplified dispatch based on the direct search method (DSM) is also introduced to relieve the computational burden further. Numerical experiments are included to understand the wind generator capacity in production cost analysis and to provide valuable information for both operational and planning problems. [ABSTRACT FROM AUTHOR]

Rechargeable batteries such as redox flow, which are not aged by frequent charging and discharging, have a quick response equivalent: to SMES and outstanding function during overload. The battery efficiency increases when the cycle period of charging/discharging becomes shorter. In addition to leveling load, the battery is advantageous for secondary control in the power system and maintenance of power quality of distributed power, resources. In this paper, we study the control performance of RF battery systems in its application to LFC. Using dynamic simulation, we show that the LFC capacity of RF battery systems is ten times that of fossil power systems due to quick response characteristics. [ABSTRACT FROM AUTHOR]

We report on the extension of a general stochastic simulation approach for power systems with integrated renewable resources to also incorporate the representation of utility-scale storage resources. The extended approach deploys models of the energy storage resources to emulate their scheduling and operations in the transmission-constrained hourly day-ahead markets. To this end, we formulate a scheduling optimization problem to determine the operational schedule of the controllable storage resources in coordination with the demands and the various supply resources, including the conventional and renewable resources. The incorporation of the scheduling optimization problem into the Monte Carlo simulation framework takes full advantage of the structural characteristics in the construction of the so-called sample paths for the stochastic simulation approach and to ensure its numerical tractability. The extended methodology has the capability to quantify the power system economics, emissions and reliability variable effects over longer-term periods for power systems with the storage resources. Applications of the approach include planning and investment studies and the formulation and analysis of policy. We illustrate the capabilities and effectiveness of the simulation approach on representative study cases on modified IEEE 118 and WECC 240-bus systems. These results provide valuable insights into the impacts of energy storage resources on the performance of power systems with integrated wind resources. [ABSTRACT FROM PUBLISHER]

Ammonia is a common contaminant in municipalities where human waste causes nitrification of local water bodies. In mining, ammonia contamination occurs as a byproduct of biological water treatment, from the use of ammonium nitrate fuel oil in explosives, and from the exposure of ammonia rich soils during the excavation process. In particular, gold mine effluent represents a significant source of ammonia and nitrogen-based contaminants. Current biological and abiotic treatment processes are difficult to employ at the scale required at mine sites due to the high operating costs, or are limited in effectiveness due to a lack of natural resources required to facilitate the treatment. This article evaluates the use of electrooxidation as a cost effective alternative to treating ammonia-laden wastewater in mining applications. Two mixed metal oxide electrodes are assessed in this article: IrO $_{2}$ /Ti and RuO $_{2}$ /Ti anodes. A Monte Carlo simulation is performed to determine a probabilistic range of capital and operating expenditure for a mining operation deploying an electrooxidation wastewater treatment system. The lowest capital cost of operating the electrochemical treatment occurs at a current density of 200 A/m $^{2}$ , where the number of cells required for treatment is minimized. [ABSTRACT FROM AUTHOR]

The article presents a report of the first International Conference on Monitoring and Diagnosis (CMD2006). Several topics are discussed in the session, which includes condition monitoring and diagnosis technologies under ubiquitous environment, monitoring and diagnosis system for nuclear power plant, and condition monitoring and diagnosis for system environmental performance.

Independent of the chosen model, the representation of hydrothermal systems is a very difficult issue. A large number of studies and investigations have taken place on the subject. The variety of approaches arises due to the different models chosen but also due to the different features of each real hydrothermal system. There are predominantly thermal systems, where the hydraulic contribution is marginal and the main efforts are directed to represent thermal unit and in large-scale hydroelectric systems, the modeling of the hydroplants is the main concern. Instead, in the Chilean case, a relative balance exists between these two types of generation. This is the main reason that the developed model makes a special effort to represent both types of units in the best possible way.

The United States, ranking third among countries in both population and land area, is geographically and ethnically diverse. The 50 states, admitted one at a time to the Union over a period of about 175 years, reflect this diversity in historical development, population, population density, land area, and natural resources. State populations vary by as much as nearly 70 times and state land area by a factor greater than 400. Consequently, industry types, population demographics, and involvement of state governments in occupational health and safety vary among states. The 2011–2018 Bureau of Labor Statistics (BLS) occupational and electrical fatality data are used to identify states with higher numbers of fatal injuries and higher incidence rates. The 2011–2018 BLS data and occupational safety and health administration (OSHA) records are reviewed to characterize worker occupations and incidents. The five states with the highest numbers of electrical fatalities are discussed. The 12 states with the highest electrical fatality incidence rates are also reviewed. The potential factors contributing to higher numbers of fatal electrical injuries and incidence rates are explored. These include industry type, worker demographics, climate, and state legislation and culture. Failure to reach workers and more effective ways to reach workers at risk for electrical injury are addressed. [ABSTRACT FROM AUTHOR]

Presenta a discussion on the paper, "Gas-Electricity Coordination in Competitive Markets Under Renewable Energy Uncertainty." [ABSTRACT FROM PUBLISHER]

RF spectrum represents a limited natural resource. The increasing numbers of wireless devices demand more and more spectrum for diverse future applications and services. CR is explored as a technological solution to the current paradigm of spectrum scarcity by opportunistically sharing the spectrum with licensed users. FD operation further enhances the performance of CR with higher throughput and optimized sensing time. Tactical radios are traditionally operated in the licensed frequency bands. To comply with the soaring demands, alternative means are explored to share the spectrum among tactical users. In this article, an FD-CR integrated with tri-band operation and dynamic spectrum shaping is proposed for tactical communications. The proposed radio is implemented in the Zynq SDR platform. The performance results reveal that the FD-CR offers higher throughput, higher probability of detection (Pd > 0.9), and optimized sensing time, which empowers the system to be ideally suitable for tactical communication networks. [ABSTRACT FROM AUTHOR]

This paper experimentally evaluates the assessment of precise point positioning (PPP) using the Natural Resources Canada (NRCan) Ultra-Rapid GPS products to serve as a short latency time-transfer tool to assist timing laboratories in operational maintenance of frequency standards and time scale dissemination. An automated data exchange and processing system has been set up to serve the international community for efficient, nearly real-time clock comparison and monitoring purposes. [ABSTRACT FROM PUBLISHER]

This letter proposes a data-driven, model-free method for load frequency control (LFC) against renewable energy uncertainties based on deep reinforcement learning (DRL) in continuous action domain. The proposed method can nonlinearly derive control strategies to minimize frequency deviation with faster response speed and stronger adaptability for unmolded system dynamics. It consists of offline optimization of LFC strategies with DRL and continuous action search, and online control with policy network where features are extracted by stacked denoising auto-encoders. Numerical simulations verify the effectiveness and advantages of proposed method over existing approaches. [ABSTRACT FROM AUTHOR]

Extensive calculation and measurements of flow-induced vibrations (FIV) of reactor internals were made in a PWR plant to assess the structural integrity of reactor core support structure against coolant flow. The work was done to meet the requirements of the Fukushima Response Action Plan (FRAP) for enhancement of reactor safety, and the regulatory guide RG-1.20. For the core surveillance measurements the Reactor Internals Vibration Monitoring System (IVMS) has been developed based on detailed neutron noise analysis of the flux signals from the four ex-core neutron detectors. The natural frequencies, displacement and mode shapes of the reactor core barrel (CB) motion were determined with the help of IVMS. The random pressure fluctuations in reactor coolant flow due to turbulence force have been identified as the predominant cause of beam-mode deflection of CB. The dynamic FIV calculations were also made to supplement the core surveillance measurements. The calculational package employed the computational fluid dynamics, mode shape analysis, calculation of power spectral densities of flow & pressure fields and the structural response to random flow excitation forces. The dynamic loads and stiffness of the Hold-Down Spring that keeps the core structure in position against upward coolant thrust were also determined by noise measurements. Also, the boron concentration in primary coolant at any time of the core cycle has been determined with the IVMS. [ABSTRACT FROM PUBLISHER]

We present a new methodology to support an energy trading company (ETC) to devise contracting strategies under an optimal risk-averse renewable portfolio. The uncertainty in the generation of renewable energy sources is accounted for by exogenously simulated scenarios, as is customary in stochastic programming. However, we recognize that spot prices largely depend on unpredictable market conditions, making it difficult to capture its underlying stochastic process, which challenges the use of fundamental approaches for forecasting. Under such framework, industry practices make use of stress tests to validate portfolios. We then adapt the robust optimization approach to perform an endogenous stress test for the spot prices as a function of the buy-and-sell portfolio of contracts and renewable energy generation scenarios. The optimal contracting strategy is built through a bilevel optimization model that uses a hybrid approach, mixing stochastic and robust optimization. The proposed model is flexible to represent the traditional stochastic programming approach and to express the ETC's uncertainty aversion in the case where the price distribution cannot be precisely estimated. The effectiveness of the model is illustrated with examples from the Brazilian market, where the proposed approach is contrasted to its stochastic counterpart and both are benchmarked against observed market variables. [ABSTRACT FROM PUBLISHER]

The concept of sustainable nanoscience is introduced and illustrated using a focused example of plasma-based growth of carbon nanotubes. This concept relates control of energy and matter at nanoscales (Grand Science Challenges) to practical applications that are relevant to a sustainable future of humankind (Grand Societal Challenges). Specific roles of plasma-related effects in nanoscale synthesis and processing that lead to superior properties and performance of nanomaterials in relevant applications are also examined. The path toward the impact in the age of sustainable development is also discussed. [ABSTRACT FROM PUBLISHER]

The increasing penetration of renewable generation in power systems necessitates the modeling of this stochastic system infeed in operation and planning studies. The system analysis leads to multivariate uncertainty analysis problems, involving non-Normal correlated random variables. In this context, the modeling of stochastic dependence is paramount for obtaining accurate results; it corresponds to the concurrent behavior of the random variables, having a major impact to the aggregate uncertainty (in problems where the random variables correspond to spatially spread stochastic infeeds) or their evolution in time (in problems where the random variables correspond to infeeds over specific time-periods). In order to investigate, measure and model stochastic dependence, one should transform all different random variables to a common domain, the rank/uniform domain, by applying the cumulative distribution function transformation. In this domain, special functions, copulae, can be used for modeling dependence. In this contribution the basic theory concerning the use of these functions for dependence modeling is presented and focus is given on a basic function, the Normal copula. The case study shows the application of the technique for the study of the large-scale integration of wind power in the Netherlands. [ABSTRACT FROM AUTHOR]

The internal output impedance of power sources and power conditioners has a strong impact on conducted interference, particularly in mixed-signal circuits. Further, the transient response of power sources and power conditioners in front of sudden load changes should not involve voltage swings beyond the operating voltage tolerance of the load. We propose a measurement method that is able to determine both the output impedance and the transient response of low-power sources and conditioners by using an operational amplifier (OA)-based dynamic load. Experimental results for some linear voltage regulators, power supplies, and batteries validate the method and demonstrate that it can reliably measure impedance magnitudes as low as 20 mΩ. [ABSTRACT FROM AUTHOR]

Energy-efficient task allocation and scheduling schemes with deterministic fault-tolerant capabilities are proposed for symmetric multiprocessor systems executing tasks with hard real-time constraints. The proposed heuristic achieves energy savings by optimally balancing the application workload among processors in a system. Based on the observation that a fault-free operation is expected to remain dominant in the near future and the probability of the worst case faults is low, an optimistic fault-tolerant heuristic is then proposed to achieve optimum energy savings in the absence of faults and meet application timing requirements in the worst case faults at the cost of energy inefficiency. Extensive simulation experiment results show that when compared to the state-of-art schemes, the proposed optimistic heuristic achieves average energy savings of up to 70 percent and exhibits higher tolerance to variations in application utilizations and more resilience to fault occurrences beyond system specification. [ABSTRACT FROM AUTHOR]

The article determines the efficacy and significance of interoperability and cooperative engineering in developing the most innovative strategy for high quality water flow for the public in the U.S. It is the main objective of industrial societies to identify the most innovative resources for environmental quality, water quality and quantity and sources of distribution. However, analysis shows that the nation's lack of interoperability is due to poor practices including improper resource allocation, poor communications, mismanagement and negligence. Utilization of cooperative engineering is an effective way to stimulate multidisciplinary and interdisciplinary scientific discussions for better water management and protection of the water sector's key assets and critical resources.

The worldwide development of the natural gas industry resulted in an integration process between electrical and gas sectors in several countries. In Brazil, this process has been taking place in a consistent manner, especially on account of the increase in gas consumption for industrial use and of the installation of thermoelectric plants. Due to the predominance of hydro plants in electric power generation, thermoelectric energy production is basically dependent on hydrology and, as a result, presents a wide annual variability. Consequently, the investment applied to gas production and transportation infrastructure may become under-utilized during a large part of the time; thus, it is important to find mechanisms apt to improve its utilization. In this respect, the present work investigates the creation of a flexible market for gas, where contracts for flexible gas supply would be offered to industrial users, who would receive the gas assigned to thermal power plants when the latter are not dispatched, and would resort to an alternate fuel when these plants are dispatched. The attractiveness of such a contract would depend, of course, on its price. The purpose of this work is to develop a stochastic model for pricing flexible gas supply contracts, taking into account the uncertainty associated to the supply-dependent on the dispatch of the thermal power plants, which have the priority of use of the gas-and the risk profile of potential consumers. [ABSTRACT FROM AUTHOR]

This article discusses sensor networks, their application within the agricultural industry, and the animal-borne nodes used to measure systems comprised of climate, soil, pasture, and animals. The agriculture industry faces many obstacles including changes in climate, problems with water supply, labor shortages, and social issues like animal welfare and food safety. Sensor networks are being used to monitor and process the complex facets associated with ecosystems and farming. Sensor networks can impact the economics of farming by monitoring the condition of the land and livestock.