pinecone/core-2020-05-10-deduplication huggingface dataset:
Lead poisoning in the globally threatened marbled teal and white-headed duck in Spain

Marbled teal (Marmaronetta angustirostris) and white-headed duck (Oxyura leucocephala) are the two European ducks threatened with global extinction. We investigated lead (Pb) poisoning in stifftails (Oxyura spp., n = 83) and marbled teal (n = 80) shot or found dead or moribund in Spanish wetlands via gizzard examination and liver, bone, and blood Pb analysis. Ingested Pb shot was present in 32% of shot stifftails and 70 and 43% of dead or moribund stifftails and marbled teal, respectively. Lead-shot ingestion was more frequent in Valencia (eastern Spain), where Pb-shot densities were higher and grit scarcer. Selection of larger grit similar in size to Pb shot may explain the higher rate of Pb-shot ingestion observed in stifftails. Ingested shot was found more frequently in juvenile stifftails than in adults. Lead bone concentrations were higher in ducklings <9 d old than in fully grown teal and were also higher in adult than in juvenile teal. Our results show the need for a ban of Pb shot for waterfowl hunting in Spain and the cleanup of spent shot at major wetlands
Metabolism and distribution of p,p'-DDT during flight of the white-crowned sparrow, Zonotrichia leucophrys

This study evaluated the interactions of flight, fasting, and 1,1,1-trichloro-bis(4-chlorophenyl)ethane (p,p′-DDT) loading on residue metabolism and distribution in recently exposed white-crowned sparrows (Zonotrichia leucophrys). Female sparrows were dosed with 5 mg p,p′-DDT per kg body weight over 3 d. Following 1 d of recovery, sparrows were flown in a wind tunnel for up to 140 min, in 15-min blocks. Food was withheld from the start of the flight period until birds were euthanized. DDT, 1,1-dichloro-2,2-bis(4 chlorophenyl)ethane (DDD), and 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (DDE) were present in all tissues examined. 1-Chloro-2,2-bis(4-chlorophenyl)ethene (DDµ), 1,1-bis(4-chlorophenyl)ethane (p,p′-DDη), and 2,2-bis(4-chlorophenyl)ethanol (p,p′-DDOH) were not found. Fasting did not significantly affect the rate of residue increase over time in any of the tissues examined. When sparrows flew and fasted simultaneously, fasting seldom contributed to an increase in tissue residues. However, the length of time flown was significantly correlated with increasing toxicant concentrations in the brain, kidney, and liver, effectively demonstrating the potential for brief flights to enhance mobilization of DDT and its metabolites. Dose, flight, and fasting also increased residues in brain tissue. These contaminant redistributions may have important ramifications on the stresses experienced by migratory birds
Analysis of the structural vulnerability of the interconnected power grid of continental Europe with the Integrated Power System and Unified Power System based on extended topological approach

Power systems as one of the key infrastructures play a crucial role in any country's economy and social life. A large-scale blackout can affect all sectors in a society such as industrial, commercial, residential, and essential public services. However, the frequency of large-scale blackouts across the world is not being reduced, although advanced technology and huge investment have been applied into power systems. Given a single blackout, it is possible to analyze the causes with the traditional engineering methods. What we want to do is not to explain the causes of blackouts but to find what are the most critical elements of the power system to improve the resilience of the system itself. As blackout can happen in different load conditions, we do not want a method that depends on the load/generation level. We want a method independent from these factors: This is the structural perspective. When the interconnection between European and Russian power grids will create the largest interconnected power grid throughout the world in terms of the scale, transmission distance, and involved countries, analyzing the vulnerability of a large-scale power grid will be useful to maintain its reliable and secure operation. To analyze the vulnerability of the interconnected power grid, in this article, we first created the interconnected transmission network between continental Europe and the Commonwealth of Independent States (CIS) and Baltic countries; then, the structural vulnerability of the interconnected power grid was analyzed from a topological point of view using our proposed extended topological method, which incorporates some electrical engineering characteristics into complex network methodology. We found that these power grids of continental Europe, the Baltic states, and the CIS countries can benefit from the interconnection because the interconnected power grid can not only improve the overall network performance of these power grids in the Baltic states and the CIS countries but also increase their structural robustness
Modeling and detection of high impedance arcing fault in medium voltage networks

In this dissertation, a universal arc representation using the Electromagnetic Transient Program (EMTP) is first developed. It is accomplished based on the bilateral interaction between EMTP network and Transient Analysis Control System (TACS) field. This arc modeling procedure is used as a useful guide to present a new model for high impedance arcing faults due to leaning trees. At the Power Systems and High Voltage Laboratory, Helsinki University of Technology (TKK), Finland, experiments have been performed to measure the fault characteristics due to leaning trees and therefore to verify the proposed model. Towards investigating detection facilities of this fault type, the fault model is incorporated at different locations in 20 kV Medium Voltage (MV) networks using the ATPdraw program, which is a graphical interface utilized to simplify the ATP/EMTP processing. Then, phase quantities and residual components are taken at different measuring nodes in the simulated networks. It is revealed that the main feature of this fault type that can enhance its detection is the periodicity of electromagnetic transients created by repetitions of the arc-reignition after each current zero-crossing. This feature is obtained considering different earthing concepts. Different detection techniques are proposed based on Discrete Wavelet Transform (DWT). The absolute sum of the wavelet coefficients in the respective frequency band is investigated for the detection purposes while several selectivity functions are proposed for the first time. The selectivity functions are presented using Logic Functions, fundamental current components and transient power directionalities. Test cases provide evidence of the efficacy of the proposed techniques.

This dissertation is written in a form of the article dissertation. Its core depends on both of a summary and six original publications.reviewe
Time-domain harmonic state estimation of nonlinear load power systems with under-determined condition based on the extended Kalman filter

This contribution presents a time-domain methodology for harmonic state estimation of power systems with nonlinear loads based on the extended Kalman filter (EKF). The output variables measurements to be used in the state estimation algorithm are selected from the simulation of the propagated harmonics in the system with an under-determined condition of the measurement matrix. The state estimation results are compared against the actual time-domain system response; both results closely agree hence verifying the effectiveness of the EKF to solve the time-domain power system state estimation. Several sampling frequencies and measurement noise are applied to assess the effects on the state estimation process, the error covariance matrix, residuals and on the execution tim
A New Sliding Mode Control Strategy for Variable-Speed Wind Turbine Power Maximization

This is the peer reviewed version of the following article: Khalfallah Tahir, Cheikh Belfedal, Tayeb Allaoui, Mouloud Denai, and M???hamed Doumi, ???A new sliding mode control strategy for variable???speed wind turbine power maximization???, International Transactions on Electrical Energy Systems, Vol. 28 (4): e2513, April 2018, which has been published in final form at https://doi.org/10.1002/etep.2513. Under embargo until 10 January 2019. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.The paper proposes a new sliding mode power control strategy for a wound-field synchronous generator (WFSG)-based variable speed wind energy conversion systems (WECS) to maximize the power extracted from the wind turbine. The proposed controller can handle the inherent nonlinearities in WECS and the randomness of the wind speed as well as the uncertainties of the model and external disturbances. To reduce the chattering phenomenon which characterize conventional sliding mode control (SMC), a sigmoid function with a variable boundary layer is proposed. The adaptive switching gains are adjusted on-line using a fuzzy logic-based technique. Several simulation scenarios were performed to evaluate the performance of the proposed control scheme. The results demonstrate that this controller provides excellent response characteristics, is robust against parameter variations and free from chattering phenomenon as compared to the conventional SMC
Electricity Pricing and Market Power - Evidence from Germany

The aim of this paper is to develop a methodology for measuring the exercise of potential market power in liberalized electricity markets. We therefore investigate producer behavior in the context of electricity pricing with respect to fundamental time-dependent marginal cost (TMC), i.e. CO2- and fuel cost. In doing so, we do not - in contrast to most current approaches to market power
investigation - rely on an estimate of the entire generation cost, which inevitably suffers from the lack of appropriate available data. Applying an analytical model of a day-ahead electricity market, we derive work-on rates, which provide information about the impact of TMC variations on electricity prices in the market
constellations of perfect competition, quasi-monopoly and monopoly. Comparing these model-based work-on rates with actual work-on rates, estimated by an adjusted first-differences regression model of German power prices on the cost for hard coal, natural gas and emission allowances, we find evidence of the exercise of market power in the period 2006 to 2008. However, our results reveal that German market competitiveness increases marginally. We confirm our results by simulating a TMC-driven diffusion model of futures power prices estimated by maximum-likelihood.
Optimal methodology for distribution systems reconfiguration based on OPF and solved by decomposition technique

This paper presents a new and efficient methodology for distribution network reconfiguration integrated with optimal power flow (OPF) based on a Benders decomposition approach. The objective minimizes power losses, balancing load among feeders and subject to constraints: capacity limit of branches, minimum and maximum power limits of substations or distributed generators, minimum deviation of bus voltages and radial optimal operation of networks. The Generalized Benders decomposition algorithm is applied to solve the problem. The formulation can be embedded under two stages; the first one is the Master problem and is formulated as a mixed integer non-linear programming problem. This stage determines the radial topology of the distribution network. The second stage is the Slave problem and is formulated as a non-linear programming problem. This stage is used to determine the feasibility of the Master problem solution by means of an OPF and provides information to formulate the linear Benders cuts that connect both problems. The model is programmed in GAMS. The effectiveness of the proposal is demonstrated through two examples extracted from the literature
On-line fault detection method for induction machines based on signal convolution

A new technique for induction motor fault detection and diagnosis is presented. This technique, which has\ud
been experimentally verified in stationary and non-stationary motor conditions, is based on the convolution\ud
of wavelet-based functions with motor stator currents. These functions are tuned to specific fault frequencies\ud
taking into account motor speed and load torque, thus considering variable operation conditions of the motor.\ud
Based on this technique an automatic system for fault diagnosis is also presented, which is suited for easy\ud
software implementation.Peer ReviewedPostprint (published version
Method for estimating core losses in switched reluctance motors

The prediction of switched reluctance motor (SRM) performance requires knowledge of core losses.
However, the calculation of iron losses in SRM is especially complex first because the flux waveforms are
nonsinusoidal and different parts of the magnetic circuit have different waveforms and second because they
are conditioned by the type of control used. This study proposes an analytical method for calculating core
losses that comprises simulation of the SRM using finite element analysis to determine the magnetization
curves, and SRM modeling, which enables transient simulations with the associated electronic power
converter run under different control strategies. The flux density waveforms in the different parts of the SRM
are derived from the flux density waveform of the stator pole that is obtained from the transient simulation.
The specific core losses (in W/kg) are separated into three parts (hysteresis losses, classical eddy current
losses and excess losses) and calculated using the waveforms and time derivatives of the local flux density.
The core losses for each part of the SRM’s magnetic circuit can be estimated using the calculated values for
specific hysteresis losses, specific classical eddy current losses and specific excess losses for each zone.
Adding these individual losses yields the total core losses. The method was applied to three-phase 6/4 SRM,
and the calculated results were compared with experimentally obtained measurements.Postprint (published version
Modeling and experimental investigation of lightning arcs and overvoltages for medium voltage distribution lines

In this dissertation, lightning overvoltages in Medium Voltage (MV) lines are thoroughly investigated. The other goal is to propose new protection schemes for the designs. The lines consist of overhead lines, underground cables and covered conductors. These overvoltage problems range from direct and indirect strokes to lightning arcs. All the models and simulations are developed using the Electromagnetic Transient Program (EMTP) and Finite Element Method (FEM), while MATLAB is used for post-processing the results and identification of the model parameters. 
 Improvement in the surge protection of MV overhead lines is demonstrated with a combination of surge arresters and a shield wire. Using the IEEE 34-node feeder injected with multiple lightning strokes, the feeder is simulated using EMTP. The response of the line is modeled both with and without the surge protection devices. The simulation study extends to the performance of a MV underground cable due to a nearby lightning discharge using FEM. The use of shield wire for limiting the overvoltage stress in the cables is proposed. A numerical analysis and simulations are performed to determine the outage rate of MV covered conductors due to lightning strokes of different characteristics. The optimum distance for surge protective devices on the conductors is also assessed. 
 An enhancement in the surge analysis of distribution lines with the shielding effect of trees is proposed. An experimental study shows that a tree can intercept a lightning stroke in the vicinity of a distribution line. This study also analyzes experimental results of the shielding effectiveness of a tree and the induced voltages existing between the tree and the distribution line. The study is extended to evaluate the induced voltage on a distribution line for larger clearances using a Rusck model. 
 This work investigates the lightning arc between an overhead line and a nearby tree under artificial rainfall. A full-scale laboratory experiment confirms that a direct stroke to a tree can cause severe damage to nearby power lines by initiating an arc channel through air to the conductors. A complete model of this phenomenon is developed by combining the existing static and dynamic arc equations. The model is accomplished by the bilateral interaction between the EMTP and Transient Analysis Control System (TACS) field. The experimental results have been reproduced by the computer simulations. 
 The performance of the arc phenomenon is examined using a typical Finnish distribution network design. Using the modified arc model, the lightning arc performance of the MV/ LV network under the influence of nearby trees and the network characteristics is evaluated
Practical applications of multi-agent systems in electric power systems

The transformation of energy networks from passive to active systems requires the embedding of intelligence within the network. One suitable approach to integrating distributed intelligent systems is multi-agent systems technology, where components of functionality run as autonomous agents capable of interaction through messaging. This provides loose coupling between components that can benefit the complex systems envisioned for the smart grid. This paper reviews the key milestones of demonstrated agent systems in the power industry and considers which aspects of agent design must still be addressed for widespread application of agent technology to occur
Pilot-Aided Acquisition Algorithms for Asynchronous DS-CDMA Systems

The problem of estimating propagation delays of orthogonally modulated signals in asynchronous DS-CDMA systems over time-varing Rayleigh-fading channels is treated in this paper. The maximum likelihood (ML) estimator and its unaffordable complexity for implementation are discussed. Some suboptimal solutions, e.g., whitened sliding correlator, MMSE estimator, subspace-based estimator, approximate ML estimator, are proposed to combat the multiple access interference in the fading channels. The performance of these estimators are evaluated with the computer simulations and shown to have better acquisition performance than the standard sliding correlator. They also achieve reduced computational complexity compared with the ML estimator, while maintaining an acceptable performance degradation
The soft-output principle - reminiscences and new developments

A major breakthrough in digital communications was the provisioning of soft outputs at each processing stage, with appropriate capabilities to use this as soft inputs in the next processing stage. This allowed for much more performant receivers especially in difficult mobile radio channel conditions, and set the stage for iterative processing. This article will outline the development of soft output algorithms over the last two decades along with associated state-of-the-art applications and conclude with an outlook towards novel applications of the soft principle
Beamforming for satellite communications in emergency situations

We consider a multi-beam Ka-band satellite communication system aimed at operating in emergency situations where terrestrial communications systems are no longer effective. In contrast to most systems which use one single beam to cover a large area, we study here the feasibility of a one beam per user concept, where a beamformer is calculated for each user. This should allow to guarantee the maximum antenna gain towards each user. We assess the performance of the minimum variance distortionless response (MVDR) beamformer and of a beamformer using a training sequence in realistic scenarios including channel, steering vector and synchronisation errors. We show that both beamformers provide a sufficiently high output signal to noise ratio in a DVB-RCS system
Spatial Frequency Scheduling for Uplink SC-FDMA based Linearly Precoded LTE Multiuser MIMO System

This paper investigates the performance of the uplink single carrier (SC) frequency division multiple access (FDMA) based linearly precoded multiuser multiple input multiple output (MIMO) systems with frequency domain packet scheduling. A mathematical expression of the received signal to interference plus noise ratio (SINR) for the studied systems is derived and a utility function based spatial frequency packet scheduling algorithms is investigated. The schedulers are shown to be able to exploit the available multiuser diversity in time, frequency and spatial domains
The persistent congestion problem of FAST-TCP: analysis and solutions

FAST-TCP achieves better performance than traditional TCP-Reno schemes, but
unfortunately it is inherently unfair to older connections due to wrong
estimations of the round-trip propagation delay.
  This paper presents a model for this anomalous behavior of FAST flows, known
as the persistent congestion problem. We first develop an elementary analysis
for a scenario with just two flows, and then build up the general case with an
arbitrary number of flows. The model correctly quantifies how much unfairness
shows up among the different connections, confirming experimental observations
made by several previous studies.
  We built on this model to develop an algorithm to obtain a good estimate of
the propagation delay for FAST-TCP that enables to achieve fairness between
aged and new connections while preserving the high throughput and low buffer
occupancy of the original protocol. Furthermore, our proposal only requires a
modification of the sender host, avoiding the need to upgrade the intermediate
routers in any way
TCP flow aware adaptive path switching in diffserv enabled MPLS networks

Cataloged from PDF version of article.We propose an adaptive flow-level multi-path routing-based traffic engineering solution for an IP backbone network
carrying TCP/IP traffic. Incoming TCP flows are switched between two explicitly routed paths, namely the primary and
secondary paths (PP and SP), for resilience and potential goodput improvement at the TCP layer. In the proposed
architecture, PPs receive a preferential treatment over SPs using differentiated services mechanisms. The reason for this
choice is not for service differentiation but for coping with the detrimental knock-on effect stemming from the use of longer
SP that is well known for conventional network load balancing algorithms. Moreover, both paths are congestion-controlled
using Explicit Congestion Notification marking at the core and Additive Increase Multiplicative Decrease rate adjustment
at the ingress nodes. The delay difference between PP and SP is estimated using two per-egress rate-controlling buffers
maintained at the ingress nodes for each path, and this delay difference is used to determine the path over which a new TCP
flow will be routed. We perform extensive simulations using ns-2 in order to demonstrate the viability of the proposed
distributed adaptive multi-path routing method in terms of per-flow TCP goodput. The proposed solution consistently
outperforms the single-path routing policy and provides substantial per-flow goodput gains under poor PP conditions.
Moreover, highest goodput improvements under the proposed scheme are achieved by flows that receive the lowest
goodputs with single-path routing, while the performance of the flows with high goodputs with single-path routing does not
deteriorate with the proposed path switching technique. Copyright # 2011 John Wiley & Sons, Ltd