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1
Cantone, L. "Simulation of freight trains with up to three traction units in radio communication." IOP Conference Series: Materials Science and Engineering 1214, no. 1 (January 1, 2022): 012039. http://dx.doi.org/10.1088/1757-899x/1214/1/012039.
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Abstract Paper reports the main results of a systematic study on longitudinal train dynamics (LTD) of long freight trains, equipped with radio communication. The simulation results have been used to prepare an experimental test campaign to test the Distributed Power System (DPS) technology. The simulations refer to up/down and level track and they compare the LTD of trains with and without DPS, for different train operations and radio link conditions. The DPS technology is proved (by simulations and test) to be a very effective way to increase the efficiency of future freight trains.
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Arcidiacono, Gabriele, Rossella Berni, Luciano Cantone, Nedka D. Nikiforova, and Pierpaolo Placidoli. "Fast Method to Evaluate Payload Effect on In-Train Forces of Freight Trains." Open Transportation Journal 12, no. 1 (February 28, 2018): 77–87. http://dx.doi.org/10.2174/1874447801812010077.
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Introduction:This paper introduces a fast method to evaluate the effect of payload distribution on in-train forces.Methods:The method is based on Strong Orthogonal Arrays (SOA) and the excellent space-filling properties of Latin Hypercube Design (LHD): SOA-based-LHD is proved to be very efficient in spanning the range of in-train forces for different types of trains (also considering distributed power/braking) and trains operations.Results:The distribution of the percentage of braked mass is used to consider the effect of payload distribution on in-train forces. Because of its computational efficiency, the method proposed here can be satisfactorily employed to perform an optimization analysis of train composition.
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Dick, C. Tyler, Ivan Atanassov, F. Bradford Kippen, and Darkhan Mussanov. "Relative train length and the infrastructure required to mitigate delays from operating combinations of normal and over-length freight trains on single-track railway lines in North America." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 233, no. 7 (November 19, 2018): 731–42. http://dx.doi.org/10.1177/0954409718809204.
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Distributed power locomotives have facilitated longer heavy-haul freight trains that improve the efficiency of railway operations. In North America, where the majority of mainlines are single track, the potential operational and economic advantages of long trains are limited by the inadequate length of many existing passing sidings (passing loops). To alleviate the challenge of operating trains that exceed the length of passing sidings, railways preserve the mainline capacity by extending passing sidings. However, industry practitioners rarely optimize the extent of infrastructure investment for the volume of over-length train traffic on a particular route. This paper investigates how different combinations of normal and over-length trains, and their relative lengths, relate to the number of siding extensions necessary to mitigate the delay performance of over-length train operation on a single-track rail corridor. The experiments used Rail Traffic Controller simulation software to determine train delay for various combinations of short and long train lengths under different directional distributions of a given daily railcar throughput volume. Simulation results suggest a relationship between the ratio of train lengths and the infrastructure expansion required to eliminate the delay introduced by operating over-length trains on the initial route. Over-length trains exhibit delay benefits from siding extensions while short trains are relatively insensitive to the expanded infrastructure. Assigning directional preference to over-length trains improves the overall average long-train delay at the expense of delay to short trains. These results will allow railway practitioners to make more informed decisions on the optimal incremental capital expansion strategy for the operation of over-length trains.
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Pfeiffer, Jakob, Xuyi Wu, and Ahmed Ayadi. "Evaluation of Three Different Approaches for Automated Time Delay Estimation for Distributed Sensor Systems of Electric Vehicles." Sensors 20, no. 2 (January 8, 2020): 351. http://dx.doi.org/10.3390/s20020351.
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Deviations between High Voltage (HV) current measurements and the corresponding real values provoke serious problems in the power trains of Electric Vehicle (EVs). Examples for these problems have inaccurate performance coordinations and unnecessary power limitations during driving or charging. The main reason for the deviations are time delays. By correcting these delays with accurate Time Delay Estimation (TDE), our data shows that we can reduce the measurement deviations from 25% of the maximum current to below 5%. In this paper, we present three different approaches for TDE. We evaluate all approaches with real data from power trains of EVs. To enable an execution on automotive Electronic Control Unit (ECUs), the focus of our evaluation lies not only on the accuracy of the TDE, but also on the computational efficiency. The proposed Linear Regression (LR) approach suffers even from small noise and offsets in the measurement data and is unsuited for our purpose. A better alternative is the Variance Minimization (VM) approach. It is not only more noise-resistant but also very efficient after the first execution. Another interesting approach are Adaptive Filter (AFs), introduced by Emadzadeh et al. Unfortunately, AFs do not reach the accuracy and efficiency of VM in our experiments. Thus, we recommend VM for TDE of HV current signals in the power train of EVs and present an additional optimization to enable its execution on ECUs.
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Li, Wei, Chunyang Chen, Hui Li, Kai Wang, Liang Xie, and Wenlu Zhang. "Analysis of the different locomotive wireless multi-traction synchronous control systems for heavy-haul combined trains and their performance." Transportation Safety and Environment 2, no. 3 (September 2020): 202–15. http://dx.doi.org/10.1093/tse/tdaa025.
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Abstract This paper looks at the heavy-haul combined train composed of different types of locomotives and its distributed power control system with a combination of 800 MHz and TD-LTE wireless communication. It analyses some key characteristic parameters that affect the synchronism and communication of the differential wireless multi-traction synchronous control systems for heavy-haul combined trains. At the same time, in order to reduce the latency of instruction and information transfer between different types of locomotives, improve the time-limit certainty of wireless transmission and optimize the control quality of multi-traction control systems for heavy-haul combined trains, a synchronism optimization strategy based on the Markov decision process on the basis of Petri networkconstruction is proposed. Relevant experiments and tests are carried out to verify the effectiveness of the synchronism optimization of the control system, which provides a guarantee for improving the differential wireless multi-traction synchronous control system for combined trains and optimizing train control.
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Wasilewski, Jacek, and Mateusz Skwarski. "Electric freight trains as distributed energy resources supporting frequency stability in power systems." IET Renewable Power Generation 14, no. 18 (December 2020): 3802–8. http://dx.doi.org/10.1049/iet-rpg.2019.1471.
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Cantone, Luciano, and Armand Toubol. "Marathon2Operation, a Shift2Rail project for radio communication and simulation of train dynamics for distributed power within long trains." Procedia Structural Integrity 24 (2019): 437–47. http://dx.doi.org/10.1016/j.prostr.2020.02.040.
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Troitskiy, Pavel S. "Algorithm for selecting motor and trailer cars in a freight train of motor-car traction according to the energy efficiency criterion." Transportation Systems and Technology 6, no. 1 (March 30, 2020): 104–19. http://dx.doi.org/10.17816/transsyst202061104-119.
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Background: improving the efficiency of freight transport is one of the main challenges facing the world's Railways. One of the most effective solutions is the introduction of distributed motor-car cargo traction. This will significantly increase the operational efficiency of the train's power plant, improve its handling, reduce the amount of destructive impact on the track, increase the capacity of railway lines and the reliability of deliveries of perishable goods.
When considering the allocation algorithm for operating the traction motors (TED) on the composition of a diesel freight trains subject to the conditions of alignment resource all TED motor coaches concluded the possibility of increasing the efficiency of multimotor traction drive modular freight trains using the proposed control algorithms for energy efficiency.
Aim: formalization of the task of selecting motor and trailer cars in a modular electric freight train.
Methods: In article the algorithm of selection of motor and trailer cars on a freight train railcar traction on the criterion of energy efficiency, the benefits of adopting a modular truck trains, are the main prerequisites for the implementation of distributed railcar truck pull. The work is based on the theory of traction calculations for train operation and is aimed at ensuring safe and energy-efficient traffic along the route sections.
Results: The developed algorithm of selection of motor and trailer cars in a unit train freight based on the condition of ensuring the traction and coupling properties of the train on the current upgrades, the development of the total volume of cargo offered for transport and energy efficiency of this type of traction.
When using the proposed algorithms for managing the energy efficiency of a motor-car electric train by selecting motor and trailer cars, adjusting the power, number of traction engines and their distribution by the composition of the traun, energy consumption on the Medvezhya Gora Noviy Poselok section can be reduced by 20.5% in the direction there and by 18.9% in the direction back without changing the traffic schedule. And when compared with a locomotive-hauled train that regulates energy consumption using the same algorithm by 4.49% and 3.61%, respectively. Energy consumption on the Krivenkovskaya Goitkh section can be reduced by 16% in the direction there and by 82% in the direction back without changing the traffic schedule. And when compared with a locomotive-hauled train that regulates energy consumption by the same algorithm by 1.61% and 65.92%, respectively.
Conclusions: The author proposes an algorithm for selecting motor and trailer cars in a freight train of motor-car traction according to the criterion of energy efficiency with the condition of ensuring traction and coupling properties on the calculated lifts. As well as the algorithm of distribution of working traction engines by the composition of the freight trains, taking into account the requirement of equalizing the resource of their work, preventing overheating and hypothermia of the fuel and energy system, and improving train handling.
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Sychenko, Viktor, Valeriy Kuznetsov, Yevheniy Kosarev, Petro Beh, Yuriy Sayenko, Bohdan Styslo, Mihail Pavlichenko, Ihor Vasilev, and Mykola Pulin. "The concept of a hybrid traction power supply system." MATEC Web of Conferences 294 (2019): 01014. http://dx.doi.org/10.1051/matecconf/201929401014.
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The growing shortage of energy resources to provide heavy traffic and high-speed traffic necessitates the development of a new power supply scheme for a traction network using sources of distributed generation of electric energy. Application of asymmetric distributed traction power system with the use of distributed generation allows to increase electric energy efficiency of the feed system of rolling stock, reduce its material capacity and increase the reliability of the functioning of the railway system as a whole. The proposed structure of the hybrid electric traction system involves the creation of a new paradigm aimed at ensuring high demands on the voltage and specific power in the traction network, which will allow to improve the quality and safety of the transportation process when increasing the energy performance indicators. This paradigm will allow to form a new philosophy of building traction power systems. The key elements of this philosophy are decentralization of generation and consumption of electric energy, the use of intelligent electric equipment, distributed power supply management in a single information space of the energy process during transportation. The peculiarity of the proposed work is the optimal combination of technological processes of transmission, consumption of electric energy and transportation, taking into account the specific conditions of functioning of the electrified section: points of connection of power sources and their type, profile of the track, schedule of trains, types of rolling stock and equipment. Conceptually, the hybrid traction power system is an electric hub, in which the inputs are generating points, and the output is the power supply system of the rolling stock. The internal structure of the electric power objects of the hub is determined by the type of transformation and accumulation of electric energy and ways of managing these objects in real time.
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Morais, Vítor A., and António P. Martins. "Traction power substation balance and losses estimation in AC railways using a power transfer device through Monte Carlo analysis." Railway Engineering Science 30, no. 1 (January 17, 2022): 71–95. http://dx.doi.org/10.1007/s40534-021-00261-y.
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AbstractThe high dynamic power requirements present in modern railway transportation systems raise research challenges for an optimal operation of railway electrification. This paper presents a Monte Carlo analysis on the application of a power transfer device installed in the neutral zone and exchanging active power between two sections. The main analyzed parameters are the active power balance in the two neighbor traction power substations and the system power losses. A simulation framework is presented to comprise the desired analysis and a universe of randomly distributed scenarios are tested to evaluate the effectiveness of the power transfer device system. The results show that the density of trains and the relative branch length of a traction power substation should be considered in the evaluation phase of the best place to install a power transfer device, towards the reduction of the operational power losses, while maintaining the two substations balanced in terms of active power.
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Wu, Qing, Colin Cole, Maksym Spiryagin, and Weihua Ma. "Preload on draft gear in freight trains." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 232, no. 6 (October 31, 2017): 1615–24. http://dx.doi.org/10.1177/0954409717738849.
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Adjusting draft gear preloads requires minimum or no structural changes to the existing coupler systems. Better or optimal preloads are more promising to be implemented than modifying other parameters such as wedge angles and spring stiffness. This paper presents a method to model draft gear preloads and investigates the numerical step-size requirements for the simulations of draft gear preloads. The implications of preloads on the draft gear impact performance, longitudinal train dynamics performance and coupler fatigue damage were also investigated. The results show that step sizes of less than 2.5 and 0.2 ms (with the fourth Runge–Kutta solver) are recommended to simulate preloads during the simulations of longitudinal train dynamics and wagon impacts, respectively. Wagon impact simulations indicate that the increase of draft gear preloads can noticeably decrease the maximum draft gear deflection during wagon impacts. Longitudinal train dynamics simulations for a distributed power train with 214 vehicles on a 320 km long track were conducted. The longitudinal train dynamics simulations indicate that, when the preload is increased from 0 to 100 kN, the difference of maximum vehicle accelerations is insignificant. When the draft gear preload is further increased to 200 or 300 kN, maximum vehicle accelerations are evidently increased. Draft gear preloads do not noticeably influence the maximum tensile coupler forces. However, preloads have evident implications for maximum compressive coupler forces, especially for the second half of the train. Coupler fatigue damage calculations show that the sum of coupler fatigue damage evidently decreases with the increase of draft gear preload. The damage for the zero preload case is 8.7 times than that of the 300 kN preload case.
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Passaglia, Christopher L., and John B. Troy. "Impact of Noise on Retinal Coding of Visual Signals." Journal of Neurophysiology 92, no. 2 (August 2004): 1023–33. http://dx.doi.org/10.1152/jn.01089.2003.
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Neural noise introduces uncertainty about the signals encoded in neural spike trains. Because of the uncertainty neurons can reliably transmit a limited amount of information. This amount is difficult to quantify for neurons that combine signals and noise in a complex manner, as many trials would be needed to estimate the joint probability distribution of stimulus and neural response accurately. The task is experimentally tractable, however, for neurons that combine signals with additive Gaussian noise. For such neurons, the joint probability distribution is well defined and information transmission rates can be computed from estimates of signal-to-noise ratio. Here we use power spectral analysis to specify the contributions of signal and noise to retinal coding of visual information. We show that in the spike trains of cat ganglion cells noise power is minimal and constant at temporal frequencies from 0.3 to 20 Hz and that it increases at higher frequencies to a plateau level that generally depends on stimulus contrast. We also show that trial-to-trial fluctuations in noise amplitude at different frequencies are uncorrelated and normally distributed. Although the contrast dependence indicates that noise at high temporal frequencies contributes nonlinearly to ganglion cell spike trains, cells in the primary visual cortex are not known to respond to stimulus modulations >20 Hz. Hence, noise in the retinal output would appear additive, white, and Gaussian from their perspective. This greatly simplifies analysis of information transmission from the eye to the primary visual cortex and perhaps other regions of the brain.
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Joelving, Frederik C., Albert Compte, and Christos Constantinidis. "Temporal Properties of Posterior Parietal Neuron Discharges During Working Memory and Passive Viewing." Journal of Neurophysiology 97, no. 3 (March 2007): 2254–66. http://dx.doi.org/10.1152/jn.00977.2006.
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Working memory is mediated by the discharges of neurons in a distributed network of brain areas. It was recently suggested that enhanced rhythmicity in neuronal activity may be critical for sustaining remembered information. To test whether working memory is characterized by unique temporal discharge patterns, we analyzed the autocorrelograms and power spectra of spike trains recorded from the posterior parietal cortex of monkeys performing a visuospatial working-memory task. We compared the intervals of active memory maintenance and fixation and repeated the same analysis in spike trains from monkeys never trained to perform any kind of memory task. The most salient effect we observed was a decrease of power in the 5- to 10-Hz frequency range during the presentation of visual stimuli. This pattern was observed both in the working-memory condition and the control condition, although it was more prominent in the former, where it persisted after cue presentation when the monkeys actively remembered the spatial location of the stimulus. Low-frequency power suppression resulted from relative refractory periods that were significantly longer in the working-memory condition and presumably emerged from local-circuit inhibition. We also detected a spectral peak in the 15- to 20-Hz range, although this was more prominent during fixation than during the stimulus and working-memory periods. Our results are in line with previous reports in prefrontal cortex and indicate that unique temporal patterns of single-neuron firing characterize persistent delay activity, although these do not involve the appearance of enhanced oscillations.
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García-Garre, Ana, and Antonio Gabaldón. "Analysis, Evaluation and Simulation of Railway Diesel-Electric and Hybrid Units as Distributed Energy Resources." Applied Sciences 9, no. 17 (September 2, 2019): 3605. http://dx.doi.org/10.3390/app9173605.
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The objective of this paper involves the analysis, identification and evaluation of different possibilities offered by technology for the improvement and the management of the use of energy and hybridization in railways: On board generation, demand response and energy storage, both in traction and auxiliary loads, considering the aggregation of resources and its stochastic nature. The paper takes into account the importance of efficient use of energy in railways, both currently (trains in service, prototypes) and in the future, considering the trends driven by energy policy scenarios (2030–2050) that will affect service and operation of units during their lifetime. A new activity has been considered that will be relevant in the future in the framework of a new electricity supply paradigm: Smart-Grids. According to this paradigm, the interaction of the Electric Power System and the Railway Supply System (somehow embedded in the Power System) will bring new opportunities for the collaboration of these two systems to perform, in a wise economic fashion, a better and more reliable operation of the complete energy system. The paper is focused on a mixed profile with low-medium traffic (passenger and freight): The first part of the route is electrified (3 kV DC catenary) whereas the second part is not electrified. Results justify that complex policies and objectives bring an opportunity to make cost-effective the hybridization of railway units, especially in low/medium traffic lines, which improves their social and economic sustainability.
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Binduhewa, Prabath J. "Sizing Algorithm for a Photovoltaic System along an Urban Railway Network towards Net Zero Emission." International Journal of Photoenergy 2021 (December 2, 2021): 1–17. http://dx.doi.org/10.1155/2021/5523448.
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A reliable transportation system is essential for the development of a community. Especially in urban transportation, rail transportation is a faster, more comfortable way to travel for the commuters. These benefits can be valued further when the rail transportation system is with zero emissions. Electric trains can be considered a zero-emission transportation method. However, a rail transportation system operates with net-zero emissions when electricity is generated from zero-emission-based sources. Photovoltaic systems have already been integrated into railway stations and spare land owned by railways to achieve net-zero emissions. Furthermore, medium-voltage DC network and microgrid concepts have been proposed to incorporate more renewable energy sources into railway electrification systems. However, the energy generated from those systems is not enough to realise net-zero emissions, as the power requirements of an urban railway electrification system are high. Accordingly, this article investigates the possibility of implementing a photovoltaic system along the railway tracks to meet the energy demands of an urban railway electrification system so that net-zero emissions can be achieved. Other significant advantages of the proposed photovoltaic system are lower feeder losses due to distributed photovoltaic systems integrated into the railway electrification system, lower conversion losses due to the direct integration of the photovoltaic system into the railway electrification system, and the nonrequirement of additional space to install the photovoltaic system. In this paper, a photovoltaic system capacity sizing algorithm is proposed and presented by considering a railway electrification system, the daily schedule of trains, and historical photovoltaic weather data. This proposed photovoltaic system capacity sizing algorithm was evaluated considering a section of the urban railway network of Sri Lanka and a three-year, 2017-2020, photovoltaic weather data. The results indicated that the potential for photovoltaic generation by installing photovoltaic systems along a railway track is much higher than the requirement, and it is possible to meet the required train scheduling options with proper sizing. Furthermore, in the three-year analysis, it is possible to achieve 90% of the energy required for the railway electrification system with effective train scheduling methods.
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Milestone, W., Q. Hu, A. M. Loveless, A. L. Garner, and R. P. Joshi. "Modeling coupled single cell electroporation and thermal effects from nanosecond electric pulse trains." Journal of Applied Physics 132, no. 9 (September 7, 2022): 094701. http://dx.doi.org/10.1063/5.0107544.
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A distributed circuit approach is used to simulate the development of electric potentials across a cell membrane and the resulting poration dynamics for ∼700 ns duration voltage pulses. Besides electric field effects, temperature increases from a pulse train are included on an equal footing to probe heating effects. The results show (i) strong heating and power dissipation at the membrane in keeping with previous simpler models, (ii) an initial spike in the membrane temperature within 100 ns timescales, (iii) a monotonic increase in membrane temperature with successive pulses to about 8 K over twelve pulses within roughly 10 μs, and (iv) large temperature gradients in excess of 2 × 107 K/m at the polar membrane region indicative of a strong source for thermo-diffusive transport. Our results suggest that inherent heating during repeated pulse application may be used to tailor excitation sequences for maximal cellular transport, broaden the permeabilization beyond the polar regions for greater transmembrane conduction, and lower the electric field thresholds for greater efficiency in longer duration irreversible electroporation protocols. More generally, the present analysis represents an initial step toward a comprehensive analysis-based optimization for tumor treatment that could select waveforms for tissues, factor in heating effects (whether for synergistic action or to ascertain safe operating limits), and engineer temporal manipulation of wavetrains to synchronize with timescales of selective bio-processes of interest for desired transient responses.
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Yang, Xiaochuan, Wei Li, Yuntao Wang, Hao Wang, Hao Yue, and Jiangtao Huang. "Research on Aerodynamic Shape Design Scheme of a Distributed Propeller Transport Aircraft and Its Slipstream Effect." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 37, no. 2 (April 2019): 361–68. http://dx.doi.org/10.1051/jnwpu/20193720361.
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With the continuous development and widespread attention of electric propulsion technology in traditional transportation fields such as automobiles and trains, the distributed propeller propulsion technology applied to electric or hybrid electric medium and small scale aircrafts has become a new topic in aviation research. This paper presents a preliminary design scheme of a distributed propeller electric propulsion transport aircraft firstly. Then, based on Reynolds average N-S equations, combined with the SA turbulence model, and replaced the real distributed propellers with simplified disk model, the aerodynamic characteristics of the aircraft with and without slipstream under the condition of low speed and high thrust at low altitude are analyzed. Finally, the effects of pressure distribution, pitching moment characteristics and wing flow on distributed propellers are studied in detailed. The results show that the lift and drag of the aircraft with slipstream are both larger than without slipstream and with slipstream effect, the pitching moment of the wing decreases, the pitching moment of the tail increases. When the tail is far away or completely inside the region of slipstream, the difference of pitching moment of the tail with and without slipstream is little, and the difference is obvious as the tail is only partially in the region of slipstream; When the diameter of distributed propellers is far larger than the wing thickness, more propeller power is used to shove air flow away from the surface area of the wing, and resulting in an insignificant increase in the coefficient of lift.
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Manakov, Aleksandr, and Abdulaziz Rahmonberdiev. "Hazardous Electromagnetic Impact of AC 25 kV Reverse Traction Network on Railway Automation and Remote control Devices." Transport automation research 8, no. 3 (September 13, 2022): 233–51. http://dx.doi.org/10.20295/2412-9186-2022-8-03-233-251.
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During electric traction of trains, railway automation and Remote control devices, connected to rails or located in close proximity to reverse traction rail network, are affected by overvoltages and overcurrents during emergency processes in a traction network. To develop, basing on mathematical models, of means and systems for protection against overvoltages and overcurrents it is required to work out a model of hazardous electromagnetic impact source at different distances from short circuit spot to traction substation and under various operating conditions. In the article, it has been developed based on state variables method a distributed mathematical model of AC traction network with 25 kV voltage. After computer experiments, it is proposed the replacement of substituion complex scheme for a traction network with equivalent parameters for each half-wave of short-circuit current. Verification has been pursued for the proposed traction network model.
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Sychenko, Viktor G., Dmitry O. Bosiy, and Eugene M. Kosarev. "Improving the quality of voltage in the system of traction power supply of direct current." Archives of Transport 35, no. 3 (September 30, 2015): 63–70. http://dx.doi.org/10.5604/08669546.1185193.
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Purpose of the work is improved approaches to ensure the required quality parameters of voltage in the traction network based on modern technologies and equipment in the application of power distribution system. Actuality. The introduction of high-speed traffic, increase weight standards Train necessitates increasing the carrying capacity of railways. Often the carrying capacity of existing sections electrified at 3.0 kV DC power supply unit limits. Such limitations include voltage decrease on the electric current collector below the allowable value for the normal operation of 2700 (2900 for high-speed V) and heating the contact wires, thereby losing their mechanical strength. Existing power supply system of RS, which have considerable installed traction substations, can not provide the required level of power density traction network for high-speed movement within 1.5 - 2 MW / km and, respectively, the required voltage quality. At the same time, the daily loading of a powerful traction substations in providing intensive schedule of trains does not exceed 20-25%, while the energy loss in traction network peak load increases and reaches 10-15% of the energy consumed. Thus, the existing system of power traction networks is not sufficiently effective and economical, even with the application of existing methods to strengthen them. In our view, the main limiting factor for a given quality of voltage in the traction network is the use of centralized power. From this, the development of measures to improve the quality of voltage in the traction network in the implementation of high-speed traffic in a growing scarcity of energy resources is an urgent task. Scientific novelty. Using distributed power supply system with adjustable supply points combined into intelligent power supply, which enables adaptive change the characteristics of the transfer, conversion and consumption and optimize the mode of functioning of the traction power supply is suggested for improving the quality of voltage in the traction network in the implementation of high-speed and heavy traffic. Practical significance. Improving the quality of voltage in the traction network by using the proposed circuit design traction power supply will ensure the desired mode voltage and power characteristics of the traction network in the implementation of high-speed and heavy traffic while reducing electricity losses by 20-30%.
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Nourski, Kirill V., John F. Brugge, Richard A. Reale, Christopher K. Kovach, Hiroyuki Oya, Hiroto Kawasaki, Rick L. Jenison, and Matthew A. Howard. "Coding of repetitive transients by auditory cortex on posterolateral superior temporal gyrus in humans: an intracranial electrophysiology study." Journal of Neurophysiology 109, no. 5 (March 1, 2013): 1283–95. http://dx.doi.org/10.1152/jn.00718.2012.
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Evidence regarding the functional subdivisions of human auditory cortex has been slow to converge on a definite model. In part, this reflects inadequacies of current understanding of how the cortex represents temporal information in acoustic signals. To address this, we investigated spatiotemporal properties of auditory responses in human posterolateral superior temporal (PLST) gyrus to acoustic click-train stimuli using intracranial recordings from neurosurgical patients. Subjects were patients undergoing chronic invasive monitoring for refractory epilepsy. The subjects listened passively to acoustic click-train stimuli of varying durations (160 or 1,000 ms) and rates (4–200 Hz), delivered diotically via insert earphones. Multicontact subdural grids placed over the perisylvian cortex recorded intracranial electrocorticographic responses from PLST and surrounding areas. Analyses focused on averaged evoked potentials (AEPs) and high gamma (70–150 Hz) event-related band power (ERBP). Responses to click trains featured prominent AEP waveforms and increases in ERBP. The magnitude of AEPs and ERBP typically increased with click rate. Superimposed on the AEPs were frequency-following responses (FFRs), most prominent at 50-Hz click rates but still detectable at stimulus rates up to 200 Hz. Loci with the largest high gamma responses on PLST were often different from those sites that exhibited the strongest FFRs. The data indicate that responses of non-core auditory cortex of PLST represent temporal stimulus features in multiple ways. These include an isomorphic representation of periodicity (as measured by the FFR), a representation based on increases in non-phase-locked activity (as measured by high gamma ERBP), and spatially distributed patterns of activity.
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GRÜNEIS, FERDINAND. "1/f NOISE, INTERMITTENCY AND CLUSTERING POISON PROCESS." Fluctuation and Noise Letters 01, no. 02 (June 2001): R119—R130. http://dx.doi.org/10.1142/s0219477501000238.
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This paper presents an extended mathematical base for the interpretation of cluster processes in introducing an intermittent stochastic process; this is characterized by clusters of events being separated by distinct breaks so-called intermissions. The spectral features of such an intermittent process are investigated for the case that either intermission δ or duration of cluster τc is power-law distributed like tz. Correspondingly, a spectral shape like 1/fb(z) is found; a pure 1/f shape (b=1) is obtained for z = -2. The most striking result is the dependence of exponent b(z) on quotient δ/τc: we obtain b≤2 for δ > τc and b≤ 1 for δ < τc. This behavior is explained by mutual time relations between clusters which cannot be neglected in case intermissions are small in comparison to duration of clusters (δ < τc). The conditions under which superimposed intermittent processes converge to the clustering Poisson process exhibiting 1/f noise are investigated. Possible applications are discussed for 1/f noise in neuronal spike trains, ionic channels, on-off intermittency and semiconductors.
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McCarthy, John, and William Mahoney. "SCADA Threats in the Modern Airport." International Journal of Cyber Warfare and Terrorism 3, no. 4 (October 2013): 32–39. http://dx.doi.org/10.4018/ijcwt.2013100104.
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Critical infrastructures are ubiquitous in the modern world and include electrical power systems, water, gas, and other utilities, as well as trains and transportation systems including airports. This work is concerned with Supervisory Control and Data Acquisition (SCADA) systems that are at the heart of distributed critical infrastructures within airports. Modern airports are highly competitive cost driven operations that offer a range of public and private services. Many airport systems such as car parking and building control systems are SCADA controlled. This is achieved with sensors and controllers monitored over a large, geographically disperse area. To increase efficiency and to achieve cost savings, SCADA systems are now being connected to information technology system networks using TCP/IP. The merging of SCADA systems into the main IT network backbone is presenting new security problems for IT security managers. Historically, proprietary solutions, closed systems, ad-hoc design and implementation, and long system life cycles have led to significant challenges in assessing the true security posture of SCADA systems. To address this, this work seeks how SCADA systems are being integrated into the IT network within a modern airport. From this new standpoint we will be able to identify ways in which SCADA may be vulnerable to malicious attack via the IT network. The results of this work could offer solutions to increase security within airports.
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Franowicz, M. N., and D. S. Barth. "Comparison of evoked potentials and high-frequency (gamma-band) oscillating potentials in rat auditory cortex." Journal of Neurophysiology 74, no. 1 (July 1, 1995): 96–112. http://dx.doi.org/10.1152/jn.1995.74.1.96.
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1. Transient and steady-state (40 Hz) evoked potentials, as well as spontaneous and click-evoked gamma-band oscillations, were recorded from 15 lightly anesthetized rats using an 8 x 8 electrode epipial array covering auditory cortex and adjacent areas to determine and compare the spatiotemporal distributions of these four phenomena. 2. The transient evoked response replicated earlier findings in our laboratory, consisting of an initial biphasic sharp wave in area 41, a similar but delayed biphasic sharp wave in area 36, and more widely distributed slow-wave components. Spatiotemporal analysis supported a model of parallel and asynchronous activation of distinct groups of thalamocortical projections underlying the neurogenesis of these temporal components of the middle-latency auditory evoked potential (MAEP) complex. 3. The 40-Hz response to click trains was superimposed on a steady potential shift (SP), both of which were localized within primary auditory cortex. Epipial distributions of the SP were similar to those of the shortest-latency negative peak in area 41 recorded in the same animals, suggesting similar neural generators. The 40-Hz response was more focal and dissimilar from the SP and any other temporal components of the MAEP complex, suggesting that a unique subpopulation of cells underlies its neurogenesis. 4. Spontaneous gamma-band activity, as assessed by power spectrum analysis, was localized to primary and secondary auditory cortex but had a variable distribution between rats that did not conform to the cytoarchitectonic boundaries within subdivisions of this region. Digital movies computed for individual bursts of gamma-activity indicated a high degree of spatiotemporal variability within and between bursts. 5. Single-trial spectral analysis of click responses indicated an inhibition of gamma-band oscillations during most of the MAEP complex, with subsequent enhanced gamma-activity during the 300- to 350-ms slow-wave component that outlasted the MAEP by approximately 500 ms. The epipial distributions of prestimulus and enhanced poststimulus gamma-oscillations were the same. In contrast to the 40-Hz response to click trains, phase-locking of gamma-oscillations by the single click stimulus was not observed. 6. These results suggest that both the MAEP complex and the steady-state 40-Hz response with its associated SP are highly stereotyped in lightly anesthetized rodent cortex. Their spatiotemporal distributions are probably determined in large part by asynchronous activation of parallel thalamocortical projection systems. Our data suggest no direct link between either the MAEP or the steady-state 40-Hz response to spontaneous or evoked gamma-band oscillations in auditory cortex.(ABSTRACT TRUNCATED AT 400 WORDS)
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Wei, Li Ming, and Jun Lin. "Research on Loss Allocation of Power Distribution Network Based on Power Flow Tracing." Advanced Materials Research 516-517 (May 2012): 1425–28. http://dx.doi.org/10.4028/www.scientific.net/amr.516-517.1425.
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The introduction of distributed generation will bring new challenges to the theory of power electricity market. The problem of loss allocation is one of them. In the paper three contents are introduced. Firstly, a loss allocation method is proposed for power distribution network with distributed generation. Secondly, the changes of loss allocation which introduction of distributed generation before and after brings about are analyzed and compared and relevant conclusions are obtained. Lastly, a typical mini-grid with a distributed generation is simulated. Simulation results prove the correctness and feasibility of the method.
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REBAÏ, AHMED. "Comparison of methods for regression interval mapping in QTL analysis with non-normal traits." Genetical Research 69, no. 1 (February 1997): 69–74. http://dx.doi.org/10.1017/s0016672396002558.
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We compare the powers of three methods for the QTL analysis of non-normally distributed traits. We describe the nonparametric and the logistic regression approaches recently proposed in the literature and study the properties of the standard regression interval mapping method when the trait is not normally distributed. It is shown that the standard approach is robust against non-normality and behaves quite well for both continuous and discrete characters. The loss of power compared with the nonparametric or the logistic approach is generally minor. Moreover, the least squares estimation procedure of the regression interval mapping is not affected by departure from normality. The use of other approaches could be restricted to extreme cases where the trait distribution is very skewed.
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Fei, Wanghao, and Paul Moses. "Fault Current Tracing and Identification via Machine Learning Considering Distributed Energy Resources in Distribution Networks." Energies 12, no. 22 (November 14, 2019): 4333. http://dx.doi.org/10.3390/en12224333.
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The growth of intermittent distributed energy sources (DERs) in distribution grids is raising many new operational challenges for utilities. One major problem is the back feed power flows from DERs that complicate state estimation for practical problems, such as detection of lower level fault currents, that cause the poor accuracy of fault current identification for power system protection. Existing artificial intelligence (AI)-based methods, such as support vector machine (SVM), are unable to detect lower level faults especially from inverter-based DERs that offer limited fault currents. To solve this problem, a current tracing method (CTM) has been proposed to model the single distribution feeder as several independent parallel connected virtual lines that traces the detailed contribution of different current sources to the power line current. Moreover, for the first time, the enhanced current information is used as the expanded feature space of SVM to significantly improve fault current detection on the power line. The proposed method is shown to be sensitive to very low level fault currents which is validated through simulations.
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Gong, Lei, Xiaofei Fu, Shuai Gao, Peiqiang Zhao, Qingyong Luo, Lianbo Zeng, Wenting Yue, Benjian Zhang, and Bo Liu. "Characterization and Prediction of Complex Natural Fractures in the Tight Conglomerate Reservoirs: A Fractal Method." Energies 11, no. 9 (September 2, 2018): 2311. http://dx.doi.org/10.3390/en11092311.
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Using the conventional fracture parameters is difficult to characterize and predict the complex natural fractures in the tight conglomerate reservoirs. In order to quantify the fracture behaviors, a fractal method was presented in this work. Firstly, the characteristics of fractures were depicted, then the fracture fractal dimensions were calculated using the box-counting method, and finally the geological significance of the fractal method was discussed. Three types of fractures were identified, including intra-gravel fractures, gravel edge fractures and trans-gravel fractures. The calculations show that the fracture fractal dimensions distribute between 1.20 and 1.50 with correlation coefficients being above 0.98. The fracture fractal dimension has exponential correlation with the fracture areal density, porosity and permeability and can therefore be used to quantify the fracture intensity. The apertures of micro-fractures are distributed between 10 μm and 100 μm, while the apertures of macro-fractures are distributed between 50 μm and 200 μm. The areal densities of fractures are distributed between 20.0 m·m−2 and 50.0 m·m−2, with an average of 31.42 m·m−2. The cumulative frequency distribution of both fracture apertures and areal densities follow power law distribution. The fracture parameters at different scales can be predicted by extrapolating these power law distributions.
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Taheri, Saeedeh, Saeedeh Taheri, Graham Ian Brodie, Dorin Gupta, Rama Harinath Reddy Dadu, Graham Ian Brodie, Dorin Gupta, and Rama Harinath Reddy Dadu. "Effect of Microwave Radiation on Internal Inoculum of Ascochyta Blight in Lentil Seeds at Different Seed Moisture Contents." Transactions of the ASABE 62, no. 1 (2019): 33–43. http://dx.doi.org/10.13031/trans.13088.
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Abstract. Considering the development of pest and pathogen resistance to chemical treatments and the cost of developing new chemicals, proper physical methods for integrated pest management seem to be gaining interest. Microwave treatment has been considered a potential postharvest pest and disease management strategy in legume and grain seeds. The effect of this process on pathogens related to legumes, which could be expressed as a very fast and volumetric thermal treatment, has not been fully studied. In this study, a domestic microwave oven with full output power of 1100 W (company information) or 485 W (calibrated with 150 g of water) was used to treat red lentil seeds that were naturally infected with the Ascochyta blight (AB) pathogen, a problematic seedborne fungi of lentil. Microwave radiation was applied at three moisture contents of red lentil seeds (9.1%, 16%, and 19% wet basis) and two power levels (50% and 100%). Three exposure times for each moisture content and power level were selected to achieve the same final average temperatures with low and high moisture contents (approx. 65°C to 85°C). The complementary error function was used to model and compare the pathogen and seed death rates based on the normally distributed susceptibility of the AB pathogen and seed germination to microwave heating. At 9% moisture content with water activity of 0.4, the percentage of infected seeds decreased from 17% to 9% without significant loss of seed viability when a power level of 100% (9.7 W g-1) and exposure time of 51 s were applied, and the final average surface temperature reached 84°C. However, seed vigor, measured by the electrical conductivity of the seed leachate, decreased at this power level and exposure time. Despite the feasibility of fungi elimination at higher moisture content at the same final average temperatures, eliminating fungi from the seeds without harming their viability and vigor was challenging. Keywords: Ascochyta blight, Lentils, Microwave energy, Pathology.
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Sun, Binbin, Song Gao, and Chao Ma. "Mathematical Methods Applied to Economy Optimization of an Electric Vehicle with Distributed Power Train System." Mathematical Problems in Engineering 2016 (2016): 1–14. http://dx.doi.org/10.1155/2016/4949561.
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This research presents mathematical methods to develop a high-efficiency power train system for a microelectric vehicle (MEV). First of all, to get the optimal ratios of a two-speed gearbox, the functional relationship of energy consumption and transmissions is established using the design of experiment (DOE) and min-max fitting distance methods. The convex characteristic of the model and the main and interactive effects of transmissions on energy consumption are revealed and hill-climbing method is adopted to search the optimal ratios. Then, to develop an efficient and real-time drive strategy, an optimization program is proposed including shift schedule, switch law, and power distribution optimization. Particularly, to construct a mathematical predictive distribution model, firstly Latin hypercube design (LHD) method is adopted to generate random and discrete operations of the MEV; secondly the optimal power distribution coefficients under various LHD points are confirmed based on offline genetic algorithm (GA); then Gauss radial basis function (RBF) is utilized to solve the low-precision problem in polynomial model. Finally, simulation verifications of the optimized scheme are carried out. Results show that the proposed mathematical methods for the optimizations of transmissions and drive strategy are able to establish a high-efficiency power train system.
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Beyan, Oya, Ananya Choudhury, Johan van Soest, Oliver Kohlbacher, Lukas Zimmermann, Holger Stenzhorn, Md Rezaul Karim, et al. "Distributed Analytics on Sensitive Medical Data: The Personal Health Train." Data Intelligence 2, no. 1-2 (January 2020): 96–107. http://dx.doi.org/10.1162/dint_a_00032.
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In recent years, as newer technologies have evolved around the healthcare ecosystem, more and more data have been generated. Advanced analytics could power the data collected from numerous sources, both from healthcare institutions, or generated by individuals themselves via apps and devices, and lead to innovations in treatment and diagnosis of diseases; improve the care given to the patient; and empower citizens to participate in the decision-making process regarding their own health and well-being. However, the sensitive nature of the health data prohibits healthcare organizations from sharing the data. The Personal Health Train (PHT) is a novel approach, aiming to establish a distributed data analytics infrastructure enabling the (re)use of distributed healthcare data, while data owners stay in control of their own data. The main principle of the PHT is that data remain in their original location, and analytical tasks visit data sources and execute the tasks. The PHT provides a distributed, flexible approach to use data in a network of participants, incorporating the FAIR principles. It facilitates the responsible use of sensitive and/or personal data by adopting international principles and regulations. This paper presents the concepts and main components of the PHT and demonstrates how it complies with FAIR principles.
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Sharma, Chandani, and Anamika Jain. "Distributed MPP Tracking of PV through Buck Converter Using Fuzzy." TELKOMNIKA Indonesian Journal of Electrical Engineering 15, no. 2 (August 1, 2015): 197. http://dx.doi.org/10.11591/tijee.v15i2.1532.
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Photovoltaics (PV) are the most abundant, perennial, environment friendly and distributed source of energy all over the globe. In this paper, the method to increase PV extraction efficiency for 60W panel with improved DMPP (Distributed Maximum Power Point) even on changing temperature and irradiance have been mapped and discussed. In order to achieve this, the components and subsystems have been analyzed and validated. The validated models are used to maximize the power output using two different models of DC-DC Converters in MATLAB/SIMULINK environment. Closed loop Buck converter using state space nonlinear differential equations and direct component model are compared to reveal best results at Standard Test Conditions (STC). MPPT model developed can be used for obtaining maximum power output from PV even in partial presence of sun using Fuzzy Logic Controller. The Controller designed tracks highest power output for the buck converter. The model developed, using tested membership functions in FLC, can serve a platform for various real time applications using PV.
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Zhou, Yuzhong, Zhengping Lin, Liang Tu, Yufei Song, and Zhengrong Wu. "Big Data and Knowledge Graph Based Fault Diagnosis for Electric Power Systems." EAI Endorsed Transactions on Industrial Networks and Intelligent Systems 9, no. 32 (June 14, 2022): e1. http://dx.doi.org/10.4108/eetinis.v9i32.1268.
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Fault detection plays an important role in the daily maintenance of power electric system. Big data and knowledge graph (KG) have been proposed by researchers to solve many problems in industrial Internet of Things, which also give lots of potentials in improving the performance of fault detection for electric power systems. In particular, this paper analyzes a distributed knowledge graph framework for fault detection in the electric power systems, where multiple devices train their local detection models used for fault detection assisted with a central server. Each device owns its local data set composed of historical fault information and current device state, which can be used to train a local model for fault detection. To enhance the detection performance, the distributed devices interact with each other in the KG framework, where the devices ought to achieve the regional computation in addition to the model aggregation within a specified latency threshold. Through searching for the vibrant qualities together with determined ability at the devices, we enhance the knowledge graph framework by the optimum variety of energetic devices together with the restriction of latency as well as data transmission. Particularly, two data transmission bandwidth allocation (BA) schemes are developed for the distributed knowledge graph framework, through which scheme I is actually bared after the instantaneous device state information (DSI), and scheme II utilizes particle swarm optimization (PSO) technique along with the statistical DSI. The results of simulation on the examination as well as convergence are lastly demonstrated to show the advantages of the proposed distributed KG framework in the fault detection for the electric power systems.
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Baczyńska, Aleksandra, and Waldemar Niewiadomski. "Power Flow Tracing for Active Congestion Management in Modern Power Systems." Energies 13, no. 18 (September 17, 2020): 4860. http://dx.doi.org/10.3390/en13184860.
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Future power systems will be based on the more active role of distribution system and its cooperation with transmission system. The main issue, which will appear in the network, is the congestion. Congestion management will become one of the crucial elements of power system operation since Distributed Energy Resources (DERs) will be playing a more important role in power systems. Moreover, the evolution also changed the character of the systems to be more dynamic—the need for precise description of power flow and shares of particular nodes in line flows will emerge. This paper presents the potential solution to the congestion management problem by using the active role of the distribution system, which may dismantle the congestions by offering flexibility services. The tools which will be indispensable in this process will be Power Flow Tracing (PFT) methods. The main goal of this paper is to present modification of PFT method and its possible applications. The correctness of the Modified Inage Domain (MID) method is verified. The identification, verification and possible applications of the new MID method are also shown in the paper. It has been proven that the new method may be used in applications of allocation of transmission cost and in application in modern power systems for advanced congestion management.
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Humphreys, Sal, Brian Fitzgerald, John Banks, and Nic Suzor. "Fan-Based Production for Computer Games: User-Led Innovation, the ‘Drift of Value’ and Intellectual Property Rights." Media International Australia 114, no. 1 (February 2005): 16–29. http://dx.doi.org/10.1177/1329878x0511400104.
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Fan-based or third party content creation has assumed an integral place in the multi-million dollar computer games industry. The emerging production ecology that involves new kinds of distributed organisations and ad hoc networks epitomises the ‘drift of value’ from producer to consumer and allows us to understand how user-led innovation influences the creative industries. But the ability to control intellectual property rights in content production is critical to the power structures and social dynamic that are being created in this space. Trainz, a train simulation game released by Brisbane developer Auran, which relies heavily on fan-created content for its success, is used as a case study. The licence agreements between Auran and the fan creators are analysed in order to understand how the balance between the commercial and non-commercial is achieved and how the tension between open networks of collaboration and closed structures of commercial competitive environments are negotiated.
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Chen Kuang Piao, Yonni, Naser Ezzati-jivan, and Michel R. Dagenais. "Distributed Architecture for an Integrated Development Environment, Large Trace Analysis, and Visualization." Sensors 21, no. 16 (August 18, 2021): 5560. http://dx.doi.org/10.3390/s21165560.
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Integrated development environments (IDEs) provide many useful tools such as a code editor, a compiler, and a debugger for creating software. These tools are highly sophisticated, and their development requires a significant effort. Traditionally, an IDE supports different programming languages via plugins that are not usually reusable in other IDEs. Given the high complexity and constant evolution of popular programming languages, such as C++ and even Java, the effort to update those plugins has become unbearable. Thus, recent work aims to modularize IDEs and reuse the existing parser implementation directly in compilers. However, when IDE debugging tools are insufficient at detecting performance defects in large and multithreaded systems, developers must use tracing and trace visualization tools in their software development process. Those tools are often standalone applications and do not interoperate with the new modular IDEs, thus losing the power and the benefits of many features provided by the IDE. The structure and use cases of tracing tools, with the potentially massive execution traces, significantly differ from the other tools in IDEs. Thus, it is a considerable challenge, one which has not been addressed previously, to integrate them into the new modular IDEs. In this paper, we propose an efficient modular client–server architecture for trace analysis and visualization that solves those problems. The proposed architecture is well suited for performance analysis on Internet of Things (IoT) devices, where resource limitations often prohibit data collection, processing, and visualization all on the same device. The experimental evaluation demonstrated that our proposed flexible and reusable solution is scalable and has a small acceptable performance overhead compared to the standalone approach.
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Cao, Xiaoguang, Xianru Hou, and Yongzhen Bao. "The Ocular Biometry of Adult Cataract Patients on Lifeline Express Hospital Eye-Train in Rural China." Journal of Ophthalmology 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/171564.
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Aims. To describe and explore the distribution of ocular biometric parameters of adult cataract patients in rural China.Methods. Three Lifeline Express Hospital Eye-Train missions of Peking University People’s Hospital in China were chosen. 3828 adult cataract patients aged 29 to 88 years with axial length (AL) less than 27.0 mm were enrolled. The ocular biometry including visual acuity (VA), intraocular pressure, AL, corneal power (K1 andK2), and corneal endothelial counting (CEC) were collected and analysis. Corneal radius (CR) was calculated from the corneal power.Results. The participants in Zhoukou of these three missions had the worse preoperative VA (p<0.001), the lowestK1 (p<0.001),K2 (p<0.001), andK(p<0.001) and the highestK1-K2(p<0.001), moreover AL/CR more closely to 3.0. The AL,K1-K2, and AL/CR were normally distributed. But theK1,K2,K, and CEC were not normal distributions. ExceptK1, all parameters were positively skewed and peaked.Conclusion. Our study provides normative ocular biometry in a large, representative rural Chinese population. The AL is normally distributed with a positive skew and big kurtosis. The corneal powers are not normal distribution. The corneal astigmatism might have a significant effect on the visual acuity.
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Barcellona, Simone, Marzio Barresi, and Luigi Piegari. "MMC-Based PV Single-Phase System with Distributed MPPT." Energies 13, no. 15 (August 1, 2020): 3964. http://dx.doi.org/10.3390/en13153964.
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The presence and evolution of static power converters in electric grids are growing on a daily basis. Starting from the most used voltage source converter (VSC), passing through the use of multilevel converters, the most recent configuration is the so-called modular multilevel converter (MMC). Because of its intrinsic advantages, it is used not only in high-voltage systems but also in low- and medium-voltage ones to interface renewable energy sources such as photovoltaic (PV) panels. Several configurations and maximum power point tracker (MPPT) algorithms have been proposed and analyzed for MMC-PV-based systems. However, when using distributed MPPTs, partial shading conditions cause a problem. The PV panel can be directly connected to the MMC using its dc link or submodule. Based on this configuration, this paper proposes a novel control strategy that tracks both the ac grid current and ac circulating current for a single-phase low-voltage system to obtain the maximum power under any irradiance condition. The effectiveness of the proposed control strategy is demonstrated through time-domain simulation results.
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Ding, Zhang, and Lin. "A Deep-Sea Pipeline Skin Effect Electric Heat Tracing System." Energies 12, no. 13 (June 26, 2019): 2466. http://dx.doi.org/10.3390/en12132466.
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In order to ensure deep-water flowline safety, this paper combined the axial temperature distribution model of the submarine pipeline and the distributed parameter circuit model of the skin effect electric heat tracing system; such work is conducive to proving that the heating effect of the skin effect electric heat tracing system depends on the distributed circuit parameters and power frequency of the system. Due to the complexity of the power supply device, the frequency cannot be increased indefinitely. Therefore, for the case that the input of the skin electric heat tracing system is constrained, a generalized predictive control algorithm introducing the input softening factor is proposed, and the constrained generalized predictive control strategy is applied to the electric heating temperature control system of the submarine oil pipeline. Simulation results demonstrated that the control quantity of the skin effect electric heat tracing system is effectively controlled within a constraint range, and also the values of heating power and power frequency are obtained by theoretical calculations rather than empirical estimations. Moreover, compared with the conventional control algorithm, the proposed constrained generalized predictive algorithm unfolds more significant dynamic response and better adaptive adjustment ability, which verifies the feasibility of the proposed control strategy.
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Luo, Z. W., and Chung-I. Wu. "Modeling Linkage Disequilibrium Between a Polymorphic Marker Locus and a Locus Affecting Complex Dichotomous Traits in Natural Populations." Genetics 158, no. 4 (August 1, 2001): 1785–800. http://dx.doi.org/10.1093/genetics/158.4.1785.
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AbstractLinkage disequilibrium is an important topic in evolutionary and population genetics. An issue yet to be settled is the theory required to extend the linkage disequilibrium analysis to complex traits. In this study, we present theoretical analysis and methods for detecting or estimating linkage disequilibrium (LD) between a polymorphic marker locus and any one of the loci affecting a complex dichotomous trait on the basis of samples randomly or selectively collected from natural populations. Statistical properties of these methods were investigated and their powers were compared analytically or by use of Monte Carlo simulations. The results show that the disequilibrium may be detected with a power of 80% by using phenotypic records and marker genotype when both the trait and marker variants are common (30%) and the LD is relatively high (40–100% of the theoretical maximum). The maximum-likelihood approach provides accurate estimates of the model parameters as well as detection of linkage disequilibrium. The likelihood method is preferred for its higher power and reliability in parameter estimation. The approaches developed in this article are also compared to those for analyzing a continuously distributed quantitative trait. It is shown that a larger sample size is required for the dichotomous trait model to obtain the same level of power in detecting linkage disequilibrium as the continuous trait analysis. Potential use of these estimates in mapping the trait locus is also discussed.
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Trüb, Roman, Reto Da Forno, Lukas Daschinger, Andreas Biri, Jan Beutel, and Lothar Thiele. "Non-Intrusive Distributed Tracing of Wireless IoT Devices with the FlockLab 2 Testbed." ACM Transactions on Internet of Things 3, no. 1 (February 28, 2022): 1–31. http://dx.doi.org/10.1145/3480248.
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Testbeds for wireless IoT devices facilitate testing and validation of distributed target nodes. A testbed usually provides methods to control, observe, and log the execution of the software. However, most of the methods used for tracing the execution require code instrumentation and change essential properties of the observed system. Methods that are non-intrusive are typically not applicable in a distributed fashion due to a lack of time synchronization or necessary hardware/software support. In this article, we present a tracing system for validating time-critical software running on multiple distributed wireless devices that does not require code instrumentation, is non-intrusive and is designed to trace the distributed state of an entire network. For this purpose, we make use of the on-chip debug and trace hardware that is part of most modern microcontrollers. We introduce a testbed architecture as well as models and methods that accurately synchronize the timestamps of observations collected by distributed observers. In a case study, we demonstrate how the tracing system can be applied to observe the distributed state of a flooding-based low-power communication protocol for wireless sensor networks. The presented non-intrusive tracing system is implemented as a service of the publicly accessible open source FlockLab 2 testbed.
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Zhu, Yi-Hang, Gilles Callebaut, Hatice Çalık, Liesbet Van der Perre, and François Rottenberg. "Energy Efficient Access Point Placement for Distributed Massive MIMO." Network 2, no. 2 (May 11, 2022): 288–310. http://dx.doi.org/10.3390/network2020019.
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Distributed massive multiple-input multiple-output (D-mMIMO) is one of the key candidate technologies for future wireless networks. A D-mMIMO system has multiple, geographically distributed, access points (APs) jointly serving its users. First of all, this paper reports on where to position these APs to minimize the overall transmit power in actual deployments. As a second contribution, we show that it is essential to take into account both the radiation pattern of the antenna array and the environment information when optimizing AP placement. Neglecting the radiation pattern and environment information, as generally assumed in the literature, can lead to a power penalty in the order of 15 dB and 20 dB, respectively. These results have been obtained by formulating the AP placement optimization problem as a combinatorial optimization problem, which can be solved with different approaches where different channel models are applied. The proposed graph-based channel model drastically lowers the computational time with respect to using an ray-tracing simulator (RTS) for channel evaluation. The performance of the graph-based approach is validated via the RTS, showing that it achieves 5 dB power saving on average compared with a Euclidean distance-based approach, which is the most commonly used approach in the literature.
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Ortiz-Astorquiza, Camilo, Jean-François Cordeau, and Emma Frejinger. "The Locomotive Assignment Problem with Distributed Power at the Canadian National Railway Company." Transportation Science 55, no. 2 (March 2021): 510–31. http://dx.doi.org/10.1287/trsc.2020.1030.
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Some of the most important optimization problems faced by railway operators arise from the management of their locomotive fleet. In this paper, we study a general version of the locomotive assignment problem encountered at the tactical level by one of the largest railroads in North America: the Canadian National (CN) Railway Company. We present a modeling framework with two integer linear programming formulations and contribute to the state of the art by allowing decisions on each train’s operating mode (distributed power or not) over the whole (weekly) planning horizon without partitioning it winto smaller time windows. Given the difficulty in solving the problem, one of the formulations is enhanced through various refinements, such as constraint relaxations, preprocessing, and fixed cost approximations. We thus achieve a significant reduction in the required computational time to solve instances of realistic size. We also present two versions of a Benders decomposition–based algorithm to obtain feasible solutions. On average, it allows a reduction of the associated computational time by two hours. Results from an extensive computational study and a case study with data provided by CN confirm the potential benefits of the model and solution approach.
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Cerquitelli, Tania, Giovanni Malnati, and Daniele Apiletti. "Exploiting Scalable Machine-Learning Distributed Frameworks to Forecast Power Consumption of Buildings." Energies 12, no. 15 (July 31, 2019): 2933. http://dx.doi.org/10.3390/en12152933.
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The pervasive and increasing deployment of smart meters allows collecting a huge amount of fine-grained energy data in different urban scenarios. The analysis of such data is challenging and opening up a variety of interesting and new research issues across energy and computer science research areas. The key role of computer scientists is providing energy researchers and practitioners with cutting-edge and scalable analytics engines to effectively support their daily research activities, hence fostering and leveraging data-driven approaches. This paper presents SPEC, a scalable and distributed engine to predict building-specific power consumption. SPEC addresses the full analytic stack and exploits a data stream approach over sliding time windows to train a prediction model tailored to each building. The model allows us to predict the upcoming power consumption at a time instant in the near future. SPEC integrates different machine learning approaches, specifically ridge regression, artificial neural networks, and random forest regression, to predict fine-grained values of power consumption, and a classification model, the random forest classifier, to forecast a coarse consumption level. SPEC exploits state-of-the-art distributed computing frameworks to address the big data challenges in harvesting energy data: the current implementation runs on Apache Spark, the most widespread high-performance data-processing platform, and can natively scale to huge datasets. As a case study, SPEC has been tested on real data of an heating distribution network and power consumption data collected in a major Italian city. Experimental results demonstrate the effectiveness of SPEC to forecast both fine-grained values and coarse levels of power consumption of buildings.
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Slodczyk, Marcel, Alexander Ilin, Thomas Kiedrowski, Jens Schmiemann, and Vasily Ploshikhin. "Simulation Aided Process Development with Multi-Spot Strategies in Laser Powder-Bed Fusion." Advanced Materials Research 1161 (March 2021): 75–82. http://dx.doi.org/10.4028/www.scientific.net/amr.1161.75.
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A challenge in laser powder-bed fusion is to achieve high process speed while maintaining quality level of the melting tracks. One approach to increase productivity is to distribute available laser power over several laser spots, resulting in higher melting rate. Using multiple laser spots opens up new parameter spaces in comparison to the conventional single-spot exposure. In addition to classical process parameters, e.g. total laser power and scanning speed, the distribution of power to the specific spots and the respective spatial arrangement have an impact on resulting process quality and speed. Within the scope of this research work, a physically based model is presented to define multi-spot process strategies for the generation of desired melt pool dimensions. Diffractive optical elements are used in order to adjust power or spatial arrangement of multiple laser spots. Resulting melt pool has more width and less depth compared to single-spot generated melt pools. Simulations and experiments show an optimum in applied spot distance between laser spots to obtain higher melting rates.
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Wang, Shouxiang, Liang Han, and Lei Wu. "Uncertainty Tracing of Distributed Generations via Complex Affine Arithmetic Based Unbalanced Three-Phase Power Flow." IEEE Transactions on Power Systems 30, no. 6 (November 2015): 3053–62. http://dx.doi.org/10.1109/tpwrs.2014.2377042.
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Lee, J., and D. J. Patterson. "Nonlinear Valve Train Dynamics Simulation With a Distributed Parameter Model of Valve Springs." Journal of Engineering for Gas Turbines and Power 119, no. 3 (July 1, 1997): 692–98. http://dx.doi.org/10.1115/1.2817043.
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A simulation model of valve train dynamics was developed in order to investigate the vibrational behavior of a valve train under heavy normal load, especially for heavy-duty diesel engines. The nonlinear multi-degree-of-freedom model developed for this study uses input data resulting from the kinematic analysis. The valve spring was modeled as a distributed parameter system rather than a lumped mass system. The stiffness constants of each valve train component were theoretically obtained as nonlinear values. The partial differential equation describing the motion of the spring and the ordinary differential equations for other components, which were considered as a lumped mass system, were solved simultaneously without any iterations by using the numerical “Time Marching Step” method. The results of this simulation, which treated the elastic characteristics of each component as nonlinear, were more accurate than the previous studies that used simple linear elastic models.
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Qu, Zhijian, Hanxin Liu, Hanlin Wang, Xinqiang Chen, Rui Chi, and Zixiao Wang. "Cluster equilibrium scheduling method based on backpressure flow control in railway power supply systems." PLOS ONE 15, no. 12 (December 9, 2020): e0243543. http://dx.doi.org/10.1371/journal.pone.0243543.
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The purpose of the study is to solve problems, i.e., increasingly significant processing delay of massive monitoring data and imbalanced tasks in the scheduling and monitoring center for a railway network. To tackle these problems, a method by using a smooth weighted round-robin scheduling based on backpressure flow control (BF-SWRR) is proposed. The method is developed based on a model for message queues and real-time streaming computing. By using telemetry data flow as input data sources, the fields of data sources are segmented into different sets by using a distributed model of stream computing parallel processing. Moreover, the round-robin (RR) scheduling method for the distributed server is improved. The parallelism, memory occupancy, and system delay are tested by taking a high-speed train section of a certain line as an example. The result showed that the BF-SWRR method for clusters can control the delay to within 1 s. When the parallelism of distributed clusters is set to 8, occupancy rates of the CPU and memory can be decreased by about 15%. In this way, the overall load of the cluster during stream computing is more balanced.
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D'Ovidio, Gino, and Francesco Crisi. "High Speed Propulsion System for UAQ4 Magnetic Levitating Train." Materials Science Forum 721 (June 2012): 9–14. http://dx.doi.org/10.4028/www.scientific.net/msf.721.9.
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This paper presents the design of a novel high speed propulsion system for UAQ4 magnetic levitating train, the feasibility of which has been successfully tested and confirmed in laboratory. A direct-current linear stepper motor that uses permanent magnets distributed on the central beam of track as the stator and the direct current power supplied coils on-board the vehicle as the rotor is proposed and analyzed. The motor performances are evaluated by varying the system parameters by carrying out a finite element numerical model refined with experimental data. The main components of a real scale motor with speed up to 580 km/h for the UAQ4 train application is measured and discussed.
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Kim, Kinam, Sangyeol Choi, and Wootaek Kim. "Oil Churning Simulation of Reduction Gear Unit for Power Distribute Type High Speed Train Using CFD." Transaction of the Korean Society of Automotive Engineers 29, no. 8 (August 31, 2021): 765–73. http://dx.doi.org/10.7467/ksae.2021.29.8.765.
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He, Weiguo, Deyang Yin, Kaifeng Zhang, Xiangwen Zhang, and Jianyong Zheng. "Fault Detection and Diagnosis Method of Distributed Photovoltaic Array Based on Fine-Tuning Naive Bayesian Model." Energies 14, no. 14 (July 9, 2021): 4140. http://dx.doi.org/10.3390/en14144140.
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With the widespread attention and research of distributed photovoltaic (PV) systems, the fault detection and diagnosis problems of distributed PV systems has become increasingly prominent. To this end, a distributed PV array fault diagnosis method based on fine-tuning Naive Bayes model for the fault conditions of PV array such as open-circuit, short-circuit, shading, abnormal degradation, and abnormal bypass diode is proposed. First, in view of the problem of less distributed PV fault data, a fine-tuning Naive Bayes model (FTNB) is proposed to improve the diagnosis accuracy. Second, the failure sample set is used to train the model. Then, the maximum power point data of the PV inverter and the meteorological data are collected for fault diagnosis. Finally, the effectiveness and accuracy of the proposed method are verified by the analysis of simulation. In addition, this method requires only a small number of fault sample sets and no additional measurement equipment is required, which is suitable for real-time monitoring of distributed PV systems.