Journal articles on the topic 'Flow Emulator'
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Tran, Hoang, Elena Leonarduzzi, Luis De la Fuente, Robert Bruce Hull, Vineet Bansal, Calla Chennault, Pierre Gentine, Peter Melchior, Laura E. Condon, and Reed M. Maxwell. "Development of a Deep Learning Emulator for a Distributed Groundwater–Surface Water Model: ParFlow-ML." Water 13, no. 23 (December 1, 2021): 3393. http://dx.doi.org/10.3390/w13233393.
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Integrated hydrologic models solve coupled mathematical equations that represent natural processes, including groundwater, unsaturated, and overland flow. However, these models are computationally expensive. It has been recently shown that machine leaning (ML) and deep learning (DL) in particular could be used to emulate complex physical processes in the earth system. In this study, we demonstrate how a DL model can emulate transient, three-dimensional integrated hydrologic model simulations at a fraction of the computational expense. This emulator is based on a DL model previously used for modeling video dynamics, PredRNN. The emulator is trained based on physical parameters used in the original model, inputs such as hydraulic conductivity and topography, and produces spatially distributed outputs (e.g., pressure head) from which quantities such as streamflow and water table depth can be calculated. Simulation results from the emulator and ParFlow agree well with average relative biases of 0.070, 0.092, and 0.032 for streamflow, water table depth, and total water storage, respectively. Moreover, the emulator is up to 42 times faster than ParFlow. Given this promising proof of concept, our results open the door to future applications of full hydrologic model emulation, particularly at larger scales.
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Ross, Molly, and Hitesh Bindra. "Statistical Mechanics-Based Surrogates for Scalar Transport in Channel Flow." Fluids 6, no. 2 (February 10, 2021): 79. http://dx.doi.org/10.3390/fluids6020079.
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Thermal hydraulics, in certain components of nuclear reactor systems, involve complex flow scenarios, such as flows assisted by free jets and stratified flows leading to turbulent mixing and thermal fluctuations. These complex flow patterns and thermal fluctuations can be extremely critical from a reactor safety standpoint. The component-level lumped approximations (0D) or one-dimensional approximations (1D) models for such components and subsystems in safety analysis codes cannot capture the physics accurately, and may introduce a large degree of modeling uncertainty. On the other hand, high-fidelity computational fluid dynamics codes, which provide numerical solutions to the Navier–Stokes equations, are accurate but computationally intensive, and thus cannot be used for system-wide analysis. An alternate way to improve reactor safety analysis is by building reduced-order emulators from computational fluid dynamics (CFD) codes to improve system scale models. One of the key challenges in developing a reduced-order emulator is to preserve turbulent mixing and thermal fluctuations across different-length scales or time-scales. This paper presents the development of a reduced-order, non-linear, “Markovian” statistical surrogate for turbulent mixing and scalar transport. The method and its implementation are demonstrated on a canonical problem of differentially heated channel flow, and high-resolution direct numerical simulations (DNS) data are used for emulator or surrogate development. This statistical surrogate model relies on Kramers–Moyal expansion and emulates the turbulent velocity signal with a high degree of accuracy.
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Owen, Nathan E., and Lorena Liuzzo. "Impact of land use on water resources via a Gaussian process emulator with dimension reduction." Journal of Hydroinformatics 21, no. 3 (March 19, 2019): 411–26. http://dx.doi.org/10.2166/hydro.2019.067.
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Abstract The replacement of models by emulators is becoming a frequent approach in environmental science due to the reduction of computational time, and different approaches exist in the water resources modelling literature. In this work, an emulator to mimic a hydrological model at catchment scale is proposed, taking into account the effect of land use on the hydrological processes involved in water balance. The proposed approach is novel for its combination of techniques. The dimension of the temporal model output is reduced via principal component analysis, and this reduced output is approximated using Gaussian process emulators built on a conditioned Latin hypercube design to reflect constrained land use inputs. Uncertainty from both the model approximation and the dimension reduction is propagated back to the space of the original output. The emulator has been applied to simulate river flow in a rural river basin located in south west England, the Frome at East Stoke Total, but the methodology is general. Results showed that the use of the emulator for water resources assessment at catchment scale is an effective approach, providing accurate estimates of the model output as a function of land use inputs, for a reduction of the computational burden.
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Dhoolia, Pankaj, Vineet Kumar, Danish Contractor, and Sachindra Joshi. "Bootstrapping Dialog Models from Human to Human Conversation Logs." Proceedings of the AAAI Conference on Artificial Intelligence 35, no. 18 (May 18, 2021): 16024–25. http://dx.doi.org/10.1609/aaai.v35i18.18000.
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State-of-the-art commercial dialog platforms provide powerful tools to build a conversational agent. These platforms provide complete control to the dialog designer to model user-agent interactions. However, a dialog designer needs to rely on domain experts to manually build the dialog model -- by creating dialog flow nodes and modeling user intents. This process is laborious, time consuming and expensive and does not allow the designer to exploit human to human conversation logs effectively. In this work, we present a research prototype that can ingest human-to-human conversation logs between an end-user and an agent, and suggest user-intents and agent-responses, given a conversation context. We utilize human to human conversation logs to build two emulators: user and agent. An agent emulator models an agent response given the conversation context so far, and a user emulator outputs possible user responses. Our system is able to recommend conversational intents as well as conversation flow using emulators based on real-world data, thus making the process of designing a bot more efficient. To the best our knowledge this is the first system that enables data-driven dialog model creation by emulating users and agents.
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Xu, Yijun, Zhixiong Hu, Lamine Mili, Mert Korkali, and Xiao Chen. "Probabilistic Power Flow Based on a Gaussian Process Emulator." IEEE Transactions on Power Systems 35, no. 4 (July 2020): 3278–81. http://dx.doi.org/10.1109/tpwrs.2020.2983603.
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Newnes, L. B., and R. Bell. "A Framework for Modelling the Coincident Flow of Workpieces and Cutting Tools." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 210, no. 2 (April 1996): 167–76. http://dx.doi.org/10.1243/pime_proc_1996_210_102_02.
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This paper describes a framework for the concurrent modelling of workpieces and cutting tools (dual flow) and introduces a computer aided tool, the dual-flow emulator, for use in the initial investment phase of high-cost flexible machining cells (FMC) and their subsequent short-term scheduling. This facility enables designers to make decisions based on the economic performance and enhancement of proposed designs. The focus of the work is on machining cells, where an individual machining centre's cost can be in excess of one million pounds, with the tooling being three/four times more expensive than conventional tooling. With these high-cost investments, where there is a small number of expensive machines, it is essential that designers are assured a greater chance of economic success. This makes it necessary to model both the flow and management of the workpieces and cutting tools. A framework for the concurrent modelling of workpieces and cutting tools (dual flow) is introduced and the dual-flow emulator described. This dual-flow emulator can be used to explore the relative merits of alternative operating strategies and, finally, as a short-term scheduling tool as an operational performance aid. An industrial-based study has been undertaken and the economic performance of two strategies is discussed in terms of the overall specification and operational performance.
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Koper, Emilia, and Andrzej Kochan. "Testing the Smooth Driving of a Train Using a Neural Network." Sustainability 12, no. 11 (June 5, 2020): 4622. http://dx.doi.org/10.3390/su12114622.
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This article deals with the extraction of a new original parameter to characterize a railway traffic driving smoothness indicator, and its investigation is based on data obtained from a neural train emulator. This indicator of driving smoothness is an example of the sustainable value of control command and signaling technology. The pro-social and pro-environmental aspects of smooth driving are indicated and the article proposes the introduction of a new indicator for assessing the quality of rail traffic, taking into account traffic on a micro scale—the driving smoothness of a single train (also called driving flow), derived from a parameter identified in the literature—and traffic smoothness (also called traffic flow), describing traffic quality on a macro scale. At the same time, the concept of a neural train emulator is presented, providing input data to determine the value of the proposed indicator for different train models and track systems in order to test the indicator’s properties. The concept proposes the structure of an artificial neural network, the technique of obtaining test data sets and the conditions of training the network as well. An emulator based on the neural network enables the simulation of train driving, taking into account its nonlinearity and data acquisition for indicator research.
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Mosetlhe, Thapelo C., Yskandar Hamam, Shengzhi Du, and Eric Monacelli. "Appraising the Impact of Pressure Control on Leakage Flow in Water Distribution Networks." Water 13, no. 19 (September 23, 2021): 2617. http://dx.doi.org/10.3390/w13192617.
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Water losses in Water Distribution Networks (WDNs) are inevitable. This is due to joints interconnections, ageing infrastructure and excessive pressure at lower demand. Pressure control has been showing promising results as a means of minimising water loss. Furthermore, it has been shown that pressure information at critical nodes is often adequate to ensure effective control in the system. In this work, a greedy algorithm for the identification of critical nodes is presented. An emulator for the WDN solution is put forward and used to simulate the dynamics of the WDN. A model-free control scheme based on reinforcement learning is used to interact with the proposed emulator to determine optimal pressure reducing valve settings based on the pressure information from the critical node. Results show that flows through the pipes and nodal pressure heads can be reduced using this scheme. The reduction in flows and nodal pressure leads to reduced leakage flows from the system. Moreover, the control scheme used in this work relies on the current operation of the system, unlike traditional machine learning methods that require prior knowledge about the system.
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Doroszkiewicz, Joanna, Renata Romanowicz, and Adam Kiczko. "The Influence of Flow Projection Errors on Flood Hazard Estimates in Future Climate Conditions." Water 11, no. 1 (December 29, 2018): 49. http://dx.doi.org/10.3390/w11010049.
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The continuous simulation approach to assessing the impact of climate change on future flood hazards consists of a chain of consecutive actions, starting from the choice of the global climate model (GCM) driven by an assumed CO2 emission scenario, through the downscaling of climatic forcing to a catchment scale, an estimation of flow using a hydrological model, and subsequent derivation of flood hazard maps with the help of a flow routing model. The procedure has been applied to the Biala Tarnowska catchment, Southern Poland. Future climate projections of rainfall and temperature are used as inputs to the precipitation-runoff model simulating flow in part of the catchment upstream of a modeled river reach. An application of a lumped-parameter emulator instead of a distributed flow routing model, MIKE11, substantially lowers the required computation times. A comparison of maximum inundation maps derived using both the flow routing model, MIKE11, and its lump-parameter emulator shows very small differences, which supports the feasibility of the approach. The relationship derived between maximum annual inundation areas and the upstream flow of the study can be used to assess the floodplain extent response to future climate changes. The analysis shows the large influence of the one-grid-storm error in climate projections on the return period of annual maximum inundation areas and their uncertainty bounds.
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García-Martínez, Eduardo, Jesús Muñoz-Cruzado-Alba, José F. Sanz-Osorio, and Juan Manuel Perié. "Design and Experimental Validation of Power Electric Vehicle Emulator for Testing Electric Vehicle Supply Equipment (EVSE) with Vehicle-to-Grid (V2G) Capability." Applied Sciences 11, no. 23 (December 4, 2021): 11496. http://dx.doi.org/10.3390/app112311496.
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Nowadays, the global decarbonization and electrification of the world’s energy demands have led to the quick adoption of Electric Vehicle (EV) technology. Therefore, there is an urgent need to provide a wide network of fast Vehicle-to-Grid (V2G) charging stations to support the forecast demand and to enable enough autonomy of such devices. Accordingly, V2G charging stations must be prepared to work properly with every manufacturer and to provide reliable designs and validation processes. In this way, the development of power electric vehicle emulators with V2G capability is critical to enable such development. The paper presents a complete design of a power electric vehicle emulator, as well as an experimental testbench to validate the behaviour of the proposal.
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Borisenok, Sergey. "Detection and Control of Epileptiform Regime in the Hodgkin–Huxley Artificial Neural Networks via Quantum Algorithms." Cybernetics and Physics, Volume 11, 2022, Number 1 (June 2, 2022): 7–12. http://dx.doi.org/10.35470/2226-4116-2022-11-1-7-12.
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The problem of detection and the following suppression of epileptiform dynamics in artificial neural networks (ANN) still is a hot topic in modern theoretical and applied neuroscience. For the purpose of such modeling, the Hodgkin–Huxley (HH) elements are important due to the variety of their behavior such as resting, singular spikes, and spike trains and bursts. This dynamical spectrum of individual HH neurons can cause an epileptiform regime originated in the hyper-synchronization of the cell outcomes. Our model covers the detection and suppression of ictal behavior in a small ANN consisting of HH cells. The model follows our approach [Borisenok et al., 2018] for the HH neurons as a classical dynamical system driving the collective neural bursting, but here we use a quantum paradigm-based algorithm emulated with the pair of HH neurons. Such emulation becomes possible due to the complexity of the individual 4d HH dynamics. The linear chain of two HH neurons is connected to the rest of ANN and works autonomously. The first neuron plays a role of the detecting element for the hyper-synchronization in the ANN and the quantum algorithm emulator; while the second one works as a measuring element (emulation of the quantum measurement converting the signals into the classical domain) and the trigger for the feedback suppressing the epileptiform regime. We use here the speed gradient algorithm for controling the emulating neuron and discuss its pros and cons to compare with our classical model of epileptiform suppression.
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Rocchetta, Roberto, and Edoardo Patelli. "A post-contingency power flow emulator for generalized probabilistic risks assessment of power grids." Reliability Engineering & System Safety 197 (May 2020): 106817. http://dx.doi.org/10.1016/j.ress.2020.106817.
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Moreno-Rodenas, Antonio M., Vasilis Bellos, Jeroen G. Langeveld, and Francois H. L. R. Clemens. "A dynamic emulator for physically based flow simulators under varying rainfall and parametric conditions." Water Research 142 (October 2018): 512–27. http://dx.doi.org/10.1016/j.watres.2018.06.011.
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Zouheyr, Dekali, Baghli Lotfi, Lubin Thierry, and Boumediene Abdelmadjid. "Grid Side Inverter Control for a Grid Connected Synchronous Generator Based Wind Turbine Experimental Emulator." European Journal of Electrical Engineering 23, no. 1 (February 28, 2021): 1–7. http://dx.doi.org/10.18280/ejee.230101.
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This paper describes the real time implementation and control of a wind energy conversion chain emulator based on a synchronous generator (SG) using a full-scale power converter configuration. The proposed structure consists of the mechanical coupling of two 1.5 kW machines, a DC motor which emulates the static-dynamic behaviors of a three-blade wind turbine with a horizontal axis including an ideal gearbox, and a synchronous generator that ensures the electromechanical conversion and manages the different operating modes. The aim of the first part in this work is the design and the implementation of the control of the grid side converter in order to control the flow of the produced/consumed active and reactive power (PGSC / QGSC) in both directions between the generator and the grid. An improved experimental grid voltage vector-orientation control algorithm (VOC) is investigated and applied to the grid inverter to control the GSC powers independently and instantly. The control algorithms are implanted in C, using dSPACE DS1104 control board to drive the 6-IGBT’s inverter. The experimental results validate the effectiveness of the proposed control scheme of the GSC.
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Chu, Zhe, Zhijing Ye, Jiamiao Zhao, Linsheng He, and Iftikhar Rasheed. "Novel Framework-Based Routing for Task-Adaptive Mobile Networks of Unmanned Aerial Vehicular." Electronics 11, no. 3 (January 30, 2022): 425. http://dx.doi.org/10.3390/electronics11030425.
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Many practical mobile ad hoc networks (MANET) have certain tasks instead of just randomly changing each node’s positions. We call such a mission-driven network task-adaptive MANET. A typical example is the flying ad hoc network (FANET) that consist of unmanned aerial vehicles (UAVs), which may change its network topology based on different task requirements. Each node moves to new locations based on the targeted network shape. To maintain a smooth topology transformation and minimize the position changes, during shape change, a MANET typically keeps the core-area nodes more stable and allows the nodes in the outer area of the network to move more drastically. This means the entire network has an approximate framework that reflects the relatively stable nodes located in the core area. This research proposes a new routing scheme to quickly identify the optimal end-to-end path using the network framework extraction result. The proposed routing scheme ensures that the packets flow along the more stable network regions (thus with a lower packet loss rate). The framework extraction scheme is based on network shape geometry analysis for the median axis recognition. Our work has contributions to three aspects of realistic network protocol applications: (1) Provides a network multi-center election and member control methodology with detailed protocol design. (2) Creates a stable and reliable MANET framework extraction algorithm which aids in routing table generation. (3) Real-time Unix system protocol implementation and emulation based on Common Open Research Emulator (CORE) + Extendable Mobile Ad-hoc Network Emulator (EMANE). Simulation results indicate that our framework-based routing scheme outperforms a popularly used mobility-adaptive MANET routing scheme—OLSR (optimized link state routing)—in terms of throughput and delay.
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Noman, Haeeder Munther, and Mahdi Nsaif Jasim. "POX Controller and Open Flow Performance Evaluation in Software Defined Networks (SDN) Using Mininet Emulator." IOP Conference Series: Materials Science and Engineering 881 (August 11, 2020): 012102. http://dx.doi.org/10.1088/1757-899x/881/1/012102.
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Ferrari, Mario L., Matteo Pascenti, and Alessio Abrassi. "Test Rig for Emulation of Turbocharged SOFC Plants." E3S Web of Conferences 113 (2019): 02001. http://dx.doi.org/10.1051/e3sconf/201911302001.
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This work is devoted to an emulator test rig designed for experimental analysis on SOFC-based plants pressurised by a turbocharger. The utilization of a turbocharger for SOFC pressurization aims to reduce the machine costs, due to the large mass production of this component. This emulator rig is an essential plant to perform tests on the component integration, dynamic operations, control system development and prevention of risky operative conditions (e.g. surge). These are essential issues to be solved before developing expensive complete prototypes and the related commercialization. This experimental plant is based on a pressure vessel for emulating the thermal (combustor and inert ceramic material) and fluid dynamic (the volume) responses. The vessel pressurisation is obtained with a turbocharger, where the exhaust flow operating in the turbine powers the compressor. The plant is also equipped with a recuperator and with different valves for control and flexibility reasons (bleed, compressor/turbine bypass, and recuperator bypass). Preliminary experimental results are included in this work focusing attention on the turbocharger choice and on the component constraints. In details, these are the necessary experiments for choosing the suitable machine for the rig (with a good surge margin for this component coupling).
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Verdier, François S., and Bertrand Zavidovique. "A High Level Synthesis System for VLSI Image Processing Applications." VLSI Design 7, no. 4 (January 1, 1998): 321–36. http://dx.doi.org/10.1155/1998/95421.
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We present a VLSI synthesis environment dedicated to the design of image processing architectures. The environment includes a “front-end” data-flow emulator for validation of the algorithms and the RTL-synthesis system called ALPHA. The latter implements a stochastic search in the design space and produces efficient solutions considering the “restricted” domain of concerned applications. Two simulated Annealing (SA) algorithms run in sequence for data-path synthesis (scheduling and module selection) and then for control synthesis and data-path completion (binding). An interesting feature of the first optimization is the use of the data-flow graph regularity to predict the control influence in terms of the future design. A few designs have already been compiled under this environment including a default detector presented here.
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Kim, Namgi, Dongyeol Kim, Yehoon Jang, Chansu Lee, and Byoung-Dai Lee. "A New Flow Entry Replacement Scheme Considering Traffic Characteristics in Software-Defined Networks." Applied Sciences 10, no. 10 (May 22, 2020): 3590. http://dx.doi.org/10.3390/app10103590.
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The Software Defined Network (SDN) decouples control and data planes of the existing network architecture and a controller carries out centralized management and control of the network. This provides flexibility for the networks and enables efficient operation, depending on their condition. However, when the performance of switches comprising the SDN varies, any switches with low performance can cause flow table overflow and subsequent bottleneck with overhead concentrating in the controller. Besides, packet processing can be delayed, declining user QoS. The paper proposes a flow entry replacement scheme that takes into account the flow features to address the issue. The proposed Short Flow First (SFF) scheme discriminates the flow features based on the matching period of flow entry and determines a subject of the flow entry replacement with the features. For evaluation, the paper built the SDN environment using the Mininet emulator and compared the performance of the proposed SFF scheme with the representative flow entry replacement schemes. According to the results, the proposed scheme showed a good performance in the flow entry miss rate and packet delay due to failure of matching the flow entry.
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Pääkkönen, Pekka, Jere Backman, Daniel Pakkala, Jori Paananen, Kari Seppänen, and Kimmo Ahola. "Concept and Architecture for Applying Continuous Machine Learning in Multi-Access Routing at Underground Mining Vehicles." Applied Sciences 12, no. 20 (October 21, 2022): 10679. http://dx.doi.org/10.3390/app122010679.
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Autonomous moving vehicles facilitate mining of ore in underground mines. The vehicles are usually equipped with many sensor-based devices (e.g., Lidar, video camera, proximity sensor, etc.), which enable environmental monitoring, and remote control of the vehicles at the control center. Transfer of sensor-based data from the vehicles towards the control center is challenging due to limited connectivity enabled by the multi-access technologies of the communication infrastructure (e.g., 5G, Wi-Fi) within the underground mine, and the mobility of the vehicles. This paper presents design, development, and evaluation of a concept and architecture enabling continuous machine learning (ML) for optimizing route selection of real-time streaming data in a real and emulated underground mining environment. Continuous ML refers to training and inference based on the most recently available data. Experiments in the emulator indicated that utilization of a ML-based model (based on the RandomForestRegressor) in decision making achieved ~5–13% lower one-way delay in streaming data transfers, when compared to a simpler heuristic model.
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Schmidt, Wolfram, Carsten Tautorat, Niels Grabow, Sebastian Kaule, Jörg Kaminsky, and Klaus-Peter Schmitz. "Pressure sensor emulator to improve longterm stability of heart valve testing systems." Current Directions in Biomedical Engineering 5, no. 1 (September 1, 2019): 493–95. http://dx.doi.org/10.1515/cdbme-2019-0124.
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AbstractFluid mechanical characterization of artificial heart valve prostheses requires reliable measurement of temperature, flow and pressure at normal heart rate. In vitro fatigue test procedures of artificial heart valve prostheses can take several months with up to 400 million cycles to assess valve performance and durability under simulated cardiac conditions at increased pulse frequency. In both cases, a minimum of user interventions for recalibration are required. In these tests, pressure data are collected for hydrodynamic heart valve characterization and for closed-loop control of pressure loading. In our study, the improvement of commercial heart valve testing systems (Vivitro Pulse Duplicator, Vivitro Labs Inc. and VDT-3600i, BDC Laboratories) is considered by substituting the built-in disposable pressure sensors (lifetime: one week) by longterm stable sensors. The selected highly accurate sensors (86A, TE Connectivity Corp.) provide amplified, linearized, calibrated and temperature compensated analog output signals. Their stainless steel construction allows for high media compatibility with corrosive liquids. Due to different sensitivity characteristics, these sensors are not fully compatible to the testing devices. To overcome this limitation, application-specific emulator interfaces were developed to connect the new sensors to the data acquisition part of the validated valve testing systems. To stay consistent with manufacturer’s device and software specification, we utilized fast analog signal conditioning, including scaling, offset calibration, out of range alarm and status indication. Compared to the originally equipped pressure sensors, emulator parameters, such as pressure range, precision, resolution and accuracy remained unchanged or even improved. For system verification the response characteristic, long-term stability and dynamic properties were examined in comparative studies
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Segers, Laurent, Jurgen Vandendriessche, Thibaut Vandervelden, Benjamin Johan Lapauw, Bruno da Silva, An Braeken, and Abdellah Touhafi. "CABE: A Cloud-Based Acoustic Beamforming Emulator for FPGA-Based Sound Source Localization." Sensors 19, no. 18 (September 10, 2019): 3906. http://dx.doi.org/10.3390/s19183906.
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Microphone arrays are gaining in popularity thanks to the availability of low-cost microphones. Applications including sonar, binaural hearing aid devices, acoustic indoor localization techniques and speech recognition are proposed by several research groups and companies. In most of the available implementations, the microphones utilized are assumed to offer an ideal response in a given frequency domain. Several toolboxes and software can be used to obtain a theoretical response of a microphone array with a given beamforming algorithm. However, a tool facilitating the design of a microphone array taking into account the non-ideal characteristics could not be found. Moreover, generating packages facilitating the implementation on Field Programmable Gate Arrays has, to our knowledge, not been carried out yet. Visualizing the responses in 2D and 3D also poses an engineering challenge. To alleviate these shortcomings, a scalable Cloud-based Acoustic Beamforming Emulator (CABE) is proposed. The non-ideal characteristics of microphones are considered during the computations and results are validated with acoustic data captured from microphones. It is also possible to generate hardware description language packages containing delay tables facilitating the implementation of Delay-and-Sum beamformers in embedded hardware. Truncation error analysis can also be carried out for fixed-point signal processing. The effects of disabling a given group of microphones within the microphone array can also be calculated. Results and packages can be visualized with a dedicated client application. Users can create and configure several parameters of an emulation, including sound source placement, the shape of the microphone array and the required signal processing flow. Depending on the user configuration, 2D and 3D graphs showing the beamforming results, waterfall diagrams and performance metrics can be generated by the client application. The emulations are also validated with captured data from existing microphone arrays.
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Hazan, Avi, and Elishai Ezra Tsur. "Neuromorphic Neural Engineering Framework-Inspired Online Continuous Learning with Analog Circuitry." Applied Sciences 12, no. 9 (April 29, 2022): 4528. http://dx.doi.org/10.3390/app12094528.
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Neuromorphic hardware designs realize neural principles in electronics to provide high-performing, energy-efficient frameworks for machine learning. Here, we propose a neuromorphic analog design for continuous real-time learning. Our hardware design realizes the underlying principles of the neural engineering framework (NEF). NEF brings forth a theoretical framework for the representation and transformation of mathematical constructs with spiking neurons, thus providing efficient means for neuromorphic machine learning and the design of intricate dynamical systems. Our analog circuit design implements the neuromorphic prescribed error sensitivity (PES) learning rule with OZ neurons. OZ is an analog implementation of a spiking neuron, which was shown to have complete correspondence with NEF across firing rates, encoding vectors, and intercepts. We demonstrate PES-based neuromorphic representation of mathematical constructs with varying neuron configurations, the transformation of mathematical constructs, and the construction of a dynamical system with the design of an inducible leaky oscillator. We further designed a circuit emulator, allowing the evaluation of our electrical designs on a large scale. We used the circuit emulator in conjunction with a robot simulator to demonstrate adaptive learning-based control of a robotic arm with six degrees of freedom.
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Zaw, Hnin Thiri, and AungHtein Maw. "Traffic management with elephant flow detection in software defined networks (SDN)." International Journal of Electrical and Computer Engineering (IJECE) 9, no. 4 (August 1, 2019): 3203. http://dx.doi.org/10.11591/ijece.v9i4.pp3203-3211.
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Multipath routing is to distribute the incoming traffic load among available paths between source and destination hosts. Instead of using the single best path, multipath scheme can avoid the congested path. Equal Cost Multi-Path (ECMP) performs the static traffic splitting based on some tuples of the packet headers. The limitation of ECMP does not consider the network parameters such as bandwidth and delay. Unlike the traditional networks, Software-Defined Network (SDN) has many advantages to support dynamic multipath forwarding due to its special characteristics, such as separation of control and data planes, global centralized control, and programmability of network behavior. In this paper, we propose a new architecture design for dynamic multipath-based traffic management approach in the SDN, which comprises of five components: detecting long (elephant) flow, computing shortest paths, estimating end-to-end delay and bandwidth utilization, calculating least cost path and rerouting traffic flow from the ongoing path to the best path. The simulation environment is created through the usage of Mininet emulator and ONOS controller. The evaluation outcomes show that the proposed traffic management method outperforms the ECMP and reactive forwarding method for both TCP and UDP traffic.
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Lubna, Tabassum, Imtiaz Mahmud, Geon-Hwan Kim, and You-Ze Cho. "D-OLIA: A Hybrid MPTCP Congestion Control Algorithm with Network Delay Estimation." Sensors 21, no. 17 (August 27, 2021): 5764. http://dx.doi.org/10.3390/s21175764.
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With the recent evolution of mobile technology, modern devices equipped with multiple communication interfaces have become popular. The multipath transmission control protocol (MPTCP) has evolved to facilitate multiple communication interfaces through a single TCP connection for faster Internet access. MPTCP congestion control algorithms (MPTCP-CCAs) control data flow by fulfilling three design goals, i.e., ensuring improvement over single-path flows, ensuring fairness, and balancing congestion. Current MPTCP-CCAs cannot fulfill these design goals. For example, the opportunistic-linked increase algorithm (OLIA), a well-known MPTCP-CCA in load balancing, often results in low throughput because it cannot properly utilize the underlying network. In addition, the current Internet has a rapidly changing characteristic due to a large amount of short-lived traffic, making it difficult for MPTCP-CCAs to cope. An awareness of prevailing network delay conditions might help MPTCP-CCAs to utilize the network capacity fully. Therefore, we propose dynamic OLIA (D-OLIA), a hybrid MPTCP-CCA that enhances the performance of OLIA by integrating an awareness of the current network delay condition for deciding the congestion window (CWND) decrease factor. We estimate the current network delay condition, i.e., less-congested or congested, by observing the changes in the round-trip-time (RTT). Based on the estimated network delay condition, we decide the CWND decrease factor in real-time for reducing the CWND during packet loss events. We implemented D-OLIA in the Linux kernel and experimented using the Mininet emulator. The emulation results demonstrate that D-OLIA successfully estimates current network delay conditions and results in approximately a 20% increased throughput compared to the original OLIA. Compared to certain MPTCP-CCAs, it also yields a highly improved performance in terms of throughput, RTT, packet retransmissions, and fairness among the MPTCP sub-flows.
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Erdal, Daniel, Sinan Xiao, Wolfgang Nowak, and Olaf A. Cirpka. "Sampling behavioral model parameters for ensemble-based sensitivity analysis using Gaussian process emulation and active subspaces." Stochastic Environmental Research and Risk Assessment 34, no. 11 (September 20, 2020): 1813–30. http://dx.doi.org/10.1007/s00477-020-01867-0.
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Abstract Ensemble-based uncertainty quantification and global sensitivity analysis of environmental models requires generating large ensembles of parameter-sets. This can already be difficult when analyzing moderately complex models based on partial differential equations because many parameter combinations cause an implausible model behavior even though the individual parameters are within plausible ranges. In this work, we apply Gaussian Process Emulators (GPE) as surrogate models in a sampling scheme. In an active-training phase of the surrogate model, we target the behavioral boundary of the parameter space before sampling this behavioral part of the parameter space more evenly by passive sampling. Active learning increases the subsequent sampling efficiency, but its additional costs pay off only for a sufficiently large sample size. We exemplify our idea with a catchment-scale subsurface flow model with uncertain material properties, boundary conditions, and geometric descriptors of the geological structure. We then perform a global-sensitivity analysis of the resulting behavioral dataset using the active-subspace method, which requires approximating the local sensitivities of the target quantity with respect to all parameters at all sampled locations in parameter space. The Gaussian Process Emulator implicitly provides an analytical expression for this gradient, thus improving the accuracy of the active-subspace construction. When applying the GPE-based preselection, 70–90% of the samples were confirmed to be behavioral by running the full model, whereas only 0.5% of the samples were behavioral in standard Monte-Carlo sampling without preselection. The GPE method also provided local sensitivities at minimal additional costs.
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Manzello, Samuel L., Thomas G. Cleary, John R. Shields, and Jiann C. Yang. "Ignition of mulch and grasses by firebrands in wildland - urban interface fires." International Journal of Wildland Fire 15, no. 3 (2006): 427. http://dx.doi.org/10.1071/wf06031.
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Firebrands or embers are produced as trees and structures burn in wildland–urban interface (WUI) fires. It is believed that firebrand showers created in WUI fires may ignite vegetation and mulch located near homes and structures. This, in turn, may lead to ignition of homes and structures due to burning vegetation and mulch. Understanding the ignition events that are due to firebrands is important to mitigate fire spread in communities. To assess the ignition propensity of such materials, simulated firebrands of uniform geometry, but in two different sizes, were allowed to impinge on fuel beds of shredded hardwood mulch, pine straw mulch, and cut grass. The moisture content of these materials was varied. Firebrands were suspended and ignited within the test cell of the Fire Emulator/Detector Evaluator (FE/DE) apparatus. The FE/DE was used to investigate the influence of an air flow on the ignition propensity of a fuel bed. Ignition regime maps were generated for each material tested as a function of impacting firebrand size, number of deposited firebrands, air flow, and material moisture content.
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P., Senthil, Balasubramanian Prabhu Kavin, S. R. Srividhya, Ramachandran V., Kavitha C., and Wen-Cheng Lai. "Performance Evaluation of Stateful Firewall-Enabled SDN with Flow-Based Scheduling for Distributed Controllers." Electronics 11, no. 19 (September 22, 2022): 3000. http://dx.doi.org/10.3390/electronics11193000.
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Software-defined networking (SDN) is a network approach achieved by decoupling of the control and data planes. The control plane is logically centralized and the data plane is distributed across the network elements. The real-time network is in need of the incorporation of distributed controllers to maintain distributed state information of the traffic flows. Software-based solutions aid distributed SDN controllers to handle fluctuating network traffic and the controller’s configurations are dynamically programmed in real time. In this study, SDN controllers were programmed with a stateful firewall application to provide firewall functionalities without the support of committed hardware. A stateful firewall filtered traffic based on the complete context of incoming packets; it continuously evaluated the entire context of traffic flows, looking for network entry rather than specific traffic flows. In addition, a flow-based scheduling module was implemented in the distributed controllers to improve network scalability. A network cluster was configured with three distributed controllers and we experimented with three independent network topologies. The performance of the proposed network model was evaluated by measuring and analyzing metrics such as network throughput (kbps), delay (ms) and network overhead (pkt/ms) for various combinations of controllers and topologies. The results of the analysis were determined using the mininet emulator. The findings of the performance evaluation indicate that the distributed SDN controllers performs better than a centralized controller. When comparing distributed SDN with two controllers and distributed SDN with three controllers the overall network throughput is increased by 64%, the delay is decreased by 43% and network overhead is reduced by 39%.
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Rocchetta, Roberto, Enrico Zio, and Edoardo Patelli. "A power-flow emulator approach for resilience assessment of repairable power grids subject to weather-induced failures and data deficiency." Applied Energy 210 (January 2018): 339–50. http://dx.doi.org/10.1016/j.apenergy.2017.10.126.
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Meena, Ramesh Chand, Surbhi Bhatia, Rutvij H. Jhaveri, Piyush Kumar Shukla, Ankit Kumar, Neeraj Varshney, and Areej A. Malibari. "Enhancing Software-Defined Networks with Intelligent Controllers to Improve First Packet Processing Period." Electronics 12, no. 3 (January 25, 2023): 600. http://dx.doi.org/10.3390/electronics12030600.
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Software-Defined Networking (SDN) has a detailed central model that separates the data plane from the control plane. The SDN controller is in charge of monitoring network security and controlling data flow. OpenFlow-enabled routers and switches work as packet-forwarding devices in the network system. At first, OpenFlow forwarding devices like routers and switches do not know how to handle the data packets transmitted by the host. This is because they do not have any security controls, policies, or information. These packets are sent to their destination. In this situation, the OpenFlow forwarding device sends the first data packet of a host to the SDN controller, which checks the control packets for the data packet and creates flow entries in the switch flow table to act on the following categories of data packets coming from the host. These activities at the SDN controller and switch levels are time-intensive, and the first data packet from the host always takes a longer time to reach its destination. In this article, we suggest an SDN controller with instant flow entries (SDN-CIFE) to reduce the amount of time it takes for the host to transmit its first data packet. Before traffic comes from the host, our method adds the necessary flow entries to the flow table of the OpenFlow switch. The technique was made in Python and tested on a Mininet network emulator using the RYU controller. The results of the experiment show that the time it takes to process the first data packet is reduced by more than 83%.
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Ahmed, Khandakar, Jan Blech, Mark Gregory, and Heinz Schmidt. "Software Defined Networks in Industrial Automation." Journal of Sensor and Actuator Networks 7, no. 3 (August 6, 2018): 33. http://dx.doi.org/10.3390/jsan7030033.
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Trends such as the Industrial Internet of Things and Industry 4.0 have increased the need to use new and innovative network technologies in industrial automation. The growth of industrial automation communications is an outcome of the shift to harness the productivity and efficiency of manufacturing and process automation with a minimum of human intervention. Due to the ongoing evolution of industrial networks from Fieldbus technologies to Ethernet, a new opportunity has emerged to harness the benefits of Software Defined Networking (SDN). In this paper, we provide a brief overview of SDN in the industrial automation domain and propose a network architecture called the Software Defined Industrial Automation Network (SDIAN), with the objective of improving network scalability and efficiency. To match the specific considerations and requirements of having a deterministic system in an industrial network, we propose two solutions for flow creation: the Pro-active Flow Installation Scheme and the Hybrid Flow Installation Scheme. We analytically quantify the proposed solutions that alleviate the overhead incurred from the flow setup. The analytical model is verified using Monte Carlo simulations. We also evaluate the SDIAN architecture and analyze the network performance of the modified topology using the Mininet emulator. We further list and motivate SDIAN features and report on an experimental food processing plant demonstration featuring Raspberry Pi as a software-defined controller instead of traditional proprietary Programmable Logic Controllers. Our demonstration exemplifies the characteristics of SDIAN.
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Muiin, Fathul, and Henry Saptono. "IMPLEMENTASI DAN ANALISIS EFEKTIVITAS FIREWALL PADA SOFTWARE DEFINED NETWORK BERBASIS OPENFLOW." Jurnal Informatika Terpadu 4, no. 2 (September 15, 2018): 46–57. http://dx.doi.org/10.54914/jit.v4i2.153.
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Penggunaan akses internet di dunia semakin berkembang, dan selaras dengan perkembangan teknologi jaringan komputer yang semakin kompleks. Oleh karena itu, keamanan data pada sebuah komputer menjadi salah satu bagian yang sangat penting dalam sebuah jaringan. Dan SDN merupakan sebuah solusi untuk menyediakan kebutuhan jaringan komputer saat ini. Software Defined Network (SDN) merupakan pendekatan pada teknologi jaringan yang melakukan penyederhanaan terhadap kontrol dan manajemen jaringan. Pada jaringan ini nantinya akan menggunakan protokol openflow, yang prinsip utamanya memisahkan fungsi control plane dan data plane pada perangkat. Kontrol jaringan pada sebuah controller bersifat programmable, jadi dengan adanya SDN maka jaringan akan mudah diatur dan lebih fleksibel. Implementasi dan analisis firewall ini menggunakan emulator mininet untuk membuat topologi jaringan yang sederhana. Dalam pengujian firewall menggunakan bahasa XML untuk implementasi aliran data, lalu menggunakan aplikasi postman sebagai alat untuk menambahkan flow table baru pada switch, dan controller yang digunakan adalah opendaylight.
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van Gisbergen, Janne, and Jaap den Doelder. "Processability predictions for mechanically recycled blends of linear polymers." Journal of Polymer Engineering 40, no. 9 (October 25, 2020): 771–81. http://dx.doi.org/10.1515/polyeng-2019-0224.
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AbstractRecycling of thermoplastic polymers is an important element of sustainable circular economy practices. The quality of mechanically recycled polymers is a concern. A method is presented to predict the structure and processability of recycled blends of polymers based on processability knowledge of their virgin precursor components. Blending rules at molecular weight distribution level are well established and form the foundation of the new method. Two essential fundamental building blocks are combined with this foundation. First, component and blend structure are related to viscosity via tube theories. Second, viscosity is related to melt flow index via a continuum mechanics approach. Emulator equations are built based on virtual experimental designs for fast forward and reverse calculations directly relating structure to viscosity and processability. The new combined method is compared with empirical blend rules, and shows important similarities and also clear quantitative differences. Finally, the new method is applied to practical recycling quality challenges.
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Neuenhahn, M. C., J. Schleifer, H. Blume, and T. G. Noll. "Quantitative comparison of performance analysis techniques for modular and generic network-on-chip." Advances in Radio Science 7 (May 18, 2009): 107–12. http://dx.doi.org/10.5194/ars-7-107-2009.
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Abstract. NoC-specific parameters feature a huge impact on performance and implementation costs of NoC. Hence, performance and cost evaluation of these parameter-dependent NoC is crucial in different design-stages but the requirements on performance analysis differ from stage to stage. In an early design-stage an analysis technique featuring reduced complexity and limited accuracy can be applied, whereas in subsequent design-stages more accurate techniques are required. In this work several performance analysis techniques at different levels of abstraction are presented and quantitatively compared. These techniques include a static performance analysis using timing-models, a Colored Petri Net-based approach, VHDL- and SystemC-based simulators and an FPGA-based emulator. Conducting NoC-experiments with NoC-sizes from 9 to 36 functional units and various traffic patterns, characteristics of these experiments concerning accuracy, complexity and effort are derived. The performance analysis techniques discussed here are quantitatively evaluated and finally assigned to the appropriate design-stages in an automated NoC-design-flow.
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Krysik, Milosz, Krzysztof Piotrowski, and Krzysztof Turchan. "Testing Smart Grid Scenarios with Small Volume Testbed and Flexible Power Inverter." Energies 15, no. 2 (January 7, 2022): 428. http://dx.doi.org/10.3390/en15020428.
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The growing penetration of Renewable Energy Sources (RES) due to the transition to future smart grid requires a huge number of power converters that participate in the power flow. Each of these devices needs the use of a complex control and communication system, thus a platform for testing real-life scenarios is necessary. Several test techniques have been so far proposed that are subject to a trade-off between cost, test coverage, and test fidelity. This paper presents an approach for testing microgrids, by developing an emulator, with emphasis on the micro-inverter unit and the possibility of flexible configuration for different grid topologies. In contrast to other approaches, our testbed is characterized by small volume and significantly scaled-down voltages for safety purposes. The examination is concentrated specifically on the inverter behavior. The test scenarios include behaviors in case of load changes, transition between grid-tied and islanded mode, connection and removal of subsequent inverters, and prioritization of inverters.
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von Maydell, Karsten, Jan Petznik, Holger Behrends, Thomas Esch, Moiz Ahmed, Alejandro Rubio, Leon Uhse, et al. "The Networked Energy Systems Emulation Center at the German Aerospace Center DLR – bridging the gap between digital simulation and real operation of energy grids." at - Automatisierungstechnik 70, no. 12 (December 1, 2022): 1072–83. http://dx.doi.org/10.1515/auto-2022-0019.
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Abstract This paper describes the Networked Energy Systems Emulation Center – DLR-NESTEC – a platform for research on power grids of the future. The DLR-NESTEC consists of a large number of networked power electronic components with which real hardware can be emulated using a real-time simulation system. The grid networking is realized via cable emulators. The laboratory works with real physical power flows and has a connected load of 800 kVA. In addition to the emulators, real network components can be integrated into the laboratory. The sector coupling is addressed by the coupling of charging infrastructure of electric cars as well as the integration of electricity-controlled heating systems. In addition, hydrogen technologies can be integrated. The laboratory is controlled by a SCADA system coupled to high-resolution measurement equipment. With the help of DLR-NESTEC, various future questions regarding robust and safe operation sector-coupled energy networks can be addressed – for instance the operation of a grid structure with a high share of controllable loads without a superordinate control.
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Zubair Islam, Muhammad, Shahzad, Rashid Ali, Amir Haider, and Hyungseok Kim. "IoTactileSim: A Virtual Testbed for Tactile Industrial Internet of Things Services." Sensors 21, no. 24 (December 15, 2021): 8363. http://dx.doi.org/10.3390/s21248363.
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With the inclusion of tactile Internet (TI) in the industrial sector, we are at the doorstep of the tactile Industrial Internet of Things (IIoT). This provides the ability for the human operator to control and manipulate remote industrial environments in real-time. The TI use cases in IIoT demand a communication network, including ultra-low latency, ultra-high reliability, availability, and security. Additionally, the lack of the tactile IIoT testbed has made it more severe to investigate and improve the quality of services (QoS) for tactile IIoT applications. In this work, we propose a virtual testbed called IoTactileSim, that offers implementation, investigation, and management for QoS provisioning in tactile IIoT services. IoTactileSim utilizes a network emulator Mininet and robotic simulator CoppeliaSim to perform real-time haptic teleoperations in virtual and physical environments. It provides the real-time monitoring of the implemented technology parametric values, network impairments (delay, packet loss), and data flow between operator (master domain) and teleoperator (slave domain). Finally, we investigate the results of two tactile IIoT environments to prove the potential of the proposed IoTactileSim testbed.
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Shchur, Ihor, Vsevolod Shchur, Ihor Bilyakovskyy, and Mykhailo Khai. "Hardware in the loop simulative setup for testing the combined heat power generating wind turbine." International Journal of Power Electronics and Drive Systems (IJPEDS) 12, no. 1 (March 1, 2021): 499. http://dx.doi.org/10.11591/ijpeds.v12.i1.pp499-510.
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This paper describes the design and implementation of hardware in the loop (HIL) system based on induction motor wind turbine emulator for the study of the operation of a combined heat-power (CHP) generating wind energy conversion system (WECS). The energy generation part of the WECS consists of two specially designed generators that are placed on a common vertical axis, which is connected to the induction motor through a gearbox. The first generator is an electric two-armature axial PMSG and the second one is a thermal electromagnetic retarder. The software part of the HIL setup simulates the interaction of the wind flow with a vertical axis wind turbine (VAWT) and is implemented in a programmable logic controller based on the model developed in the MATLAB/Simulink. The results of experimental studies of the CHP WECS with the created HIL simulative setup at both constant and turbulent wind speeds have shown good agreement with the corresponding results of computer simulation. The created HIL simulative setup will be used for the development of an energy management system for CHP WECS.
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Saputra, Ihsan Aris, R. Rumani M., and Sofia Naning Hertiana. "Uji Performansi Algoritma Floyd-Warshall Pada Jaringan Software Defined Network (SDN)." Jurnal Elektronika dan Telekomunikasi 16, no. 2 (December 20, 2016): 52. http://dx.doi.org/10.14203/jet.v16.52-58.
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Penentuan rute pada sebuah jaringan software defined network (SDN) merupakan salah satu contoh topik yang menarik untuk diteliti. Algoritma penentuan rute terpendek pada jaringan SDN sangatlah menentukan apakah jaringan SDN yang dibangun dengan algoritma tersebut sudah optimal. Salah satu algoritma penentuan rute terpendek yaitu algoritma FloydWarshall, yang akan diuji coba dan dianalisis apakah sudah termasuk algoritma yang optimal pada jaringan SDN dengan membandingkan dengan standarisasi yang ada. Pengujian akan dilakukan dengan mengirimkan paket data, VoIP dan video dengan melihat overhead traffic dan QoS (delay dan packet loss). Algoritma Floyd-Warshall akan digunakan pada pengontrol Ryu dan menggunakan Mininet sebagai emulator jaringan dengan topologi berbasis Abiline. Hasil simulasi dan pengujian algoritma Floyd-Warshall sebagai penentuan jalur terbaik dalam jaringan SDN, mendapatkan hasil yang memenuhi standarisasi. Nilai dari QoS yang didapat untuk delay masih berada pada nilai yang menjadi standar ITU-T G.1010. Packet loss yang dihasilkan semua jenis layanan sudah memenuhi standar ITU-T G.1010 yaitu 0% hingga saat pada jaringan diberikan background traffic melebihi kapasitas link yaitu pemberian sebesar 75 Mbps. Dalam pengujian waktu konvergensi didapatkan waktu dengan rata-rata nilai 17.71446 detik. Kemudian untuk overhead traffic menunjukan bahwa perubahan overhead dipengaruhi oleh controller update dan juga flow update, dimana ketika sering terjadinya controller update dan flow update maka semakin besar juga overhead yang didapat.
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Saleh, Sherine Nagy, and Cherine Fathy. "A Novel Deep-Learning Model for Remote Driver Monitoring in SDN-Based Internet of Autonomous Vehicles Using 5G Technologies." Applied Sciences 13, no. 2 (January 8, 2023): 875. http://dx.doi.org/10.3390/app13020875.
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The rapid advancement in the Internet of Things (IoT) and its integration with Artificial Intelligence (AI) techniques are expected to play a crucial role in future Intelligent Transportation Systems (ITS). Additionally, the continuous progress in the industry of autonomous vehicles will accelerate and increase their short adoption in smart cities to allow safe, sustainable and accessible trips for passengers in different public and private means of transportation. In this article, we investigate the adoption of 5G different technologies, mainly, the Software-Defined Networks (SDN) to support the communication requirements of delegation of control of level-2 autonomous vehicles to the Remote-Control Center (RCC) in terms of ultra-low delay and reliability. This delegation occurs upon the detection of a drowsy driver using our proposed deep-learning-based technique deployed at the edge to reduce the level of accidents and road congestion. The deep learning-based model was evaluated and produced higher accuracy, precision and recall when compared to other methods. The role of SDN is to implement network slicing to achieve the Quality of Service (QoS) level required in this emergency case. Decreasing the end-to-end delay required to provide feedback control signals back to the autonomous vehicle is the aim of deploying QoS support available in an SDN-based network. Feedback control signals are sent to remotely activate the stopping system or to switch the vehicle to direct teleoperation mode. The mininet-WiFi emulator is deployed to evaluate the performance of the proposed adaptive SDN framework, which is tailored to emulate radio access networks. Our simulation experiments conducted on realistic vehicular scenarios revealed significant improvement in terms of throughput and average Round-Trip Time (RTT).
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Irfan, Muhammad, and Lailis Syafa'ah. "Quality Of Service pada Jaringan Multi Protocol Label Switching." Jurnal Teknik Industri 10, no. 2 (February 10, 2012): 142–49. http://dx.doi.org/10.22219/jtiumm.vol10.no2.142-149.
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MPLS is a work plan that was given by IETF to repair work performance of IP network. Label switching label using forwarding mechanism which has connection oriented characteristic make this technology become routing technology for future guarantec QoS with better service level. This is supporting using a protocol signals for TE-MPLS to maximize network performance balancing the network stressing with distribution that fixed on classes, queuing, and traffic schedule. This research is an analysis of TE-MPLS mechanism to design MPLS network with RSVP-TE daemon that is called emulator MPLS. This analysis used generating 2 different kinds of protocol traffic, UDP, and TCP. The measurement could be concluded that there was an efficience of MPLS network in group joint of protocol UDP network about 18,6 % for channel that is similar with traffic 2 KBRS, 3,4 %, 1,5 %, and 5,6 % for channel similar with traffic 4,8 and 16 KBRS for flow variation of MPLS network data increase 464,2 %, 479,5 %, 518 %, and 2638,5 % for each channel. The time that was needed for TCP protocol transmition of MPLS network showed efficiency 2,9 % and bit rate of MPLS increase about 0,66 %.
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Yodwong, Burin, Damien Guilbert, Wattana Kaewmanee, and Matheepot Phattanasak. "Energy Efficiency Based Control Strategy of a Three-Level Interleaved DC-DC Buck Converter Supplying a Proton Exchange Membrane Electrolyzer." Electronics 8, no. 9 (August 25, 2019): 933. http://dx.doi.org/10.3390/electronics8090933.
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To face the intensive use of natural gas and other fossil fuels to generate hydrogen, water electrolysis based on renewable energy sources (RES) seems to be a viable solution. Due to their fast response times, and high efficiency, proton exchange membrane electrolyzer (PEM EL) is the most suitable technology for long-term energy storage, combined with RES. Like fuel cells, the development of fit DC-DC converters is mandatory to interface the EL to the DC grid. Given that PEM EL operating voltages are quite low and to meet requirements in terms of output current ripples, new emerging interleaved DC-DC converter topologies seem to be the best candidates. In this work, a three-level interleaved DC-DC buck converter has been chosen to supply a PEM EL from a DC grid. Therefore, the main objective of this paper is to develop a suitable control strategy of this interleaved topology connected to a PEM EL emulator. To design the control strategy, investigations have been carried out on energy efficiency, hydrogen flow rate, and specific energy consumption. The obtained experimental results validate the performance of the converter in protecting the PEM EL during transient operations while guaranteeing correct specific energy consumption.
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Jabba, Daladier, and Pedro Acevedo. "ViTool-BC: Visualization Tool Based on Cooja Simulator for WSN." Applied Sciences 11, no. 16 (August 20, 2021): 7665. http://dx.doi.org/10.3390/app11167665.
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Evaluation and monitoring of wireless sensor networks (WSN) and the parameters defining their operations and design, such as energy consumption, latency, and stability, is a complex task due to interaction with real devices. For greater control of these variables, the use of simulators arises as an alternative. Cooja is a WSN simulator/emulator which handles the devices’ controllers and multiple communication protocol implementations, such as RPL (RPL is one of the most used protocol in IoT). However, Cooja does not consider either the implementation of an energy model (it has infinite energy consumption) nor the visual behavior of the topology construction, although these aspects are crucial for effective network analysis and decision taking. This paper presents the design and the implementation of ViTool-BC, a software built on top of Cooja, which allows the creation of different energy estimation models and also to visualize in real time the behavior of WSN topology construction. In addition, ViTool-BC offers a heat map of energy consumption traces. Therefore, this tool helps researchers to monitor in real time the topology construction, node disconnection, and battery depletion, aspects to be considered in the analysis of the available routing protocols in Cooja.
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Wahyutama, Aria Bisma, and Mintae Hwang. "Auto-Scoring Feature Based on Sentence Transformer Similarity Check with Korean Sentences Spoken by Foreigners." Applied Sciences 13, no. 1 (December 28, 2022): 373. http://dx.doi.org/10.3390/app13010373.
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This paper contains the development of a training service for foreigners to help them increase their ability to speak Korean. The service developed in this paper is implemented in the form of a mobile application that shows specific Korean sentences to the user for them to record themselves speaking the sentence. The objective is to generate the score automatically based on how similar the recorded voice with the actual sentence using Speech-To-Text (STT) engines and Sentence Transformers. The application is developed by selecting the four most commonly known STT engines with similar features, which are Google API, Microsoft Azure, Naver Clova, and IBM Watson, which are put into a Rest API along with the Sentence Transformer. The mobile application will record the user’s voice and send it to the Rest API. The STT engines will transcribe the file into a text and then feed it into a Sentence Transformer to generate the score based on their similarity. After measuring the response time and consistency as the performance evaluation by simulating a scenario using an Android emulator, Microsoft Azure with 1.13 s is found to be the fastest STT engine and Naver Clova is found to be the least consistent engine with nine different transcribe results.
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Samano-Ortega, Víctor, Heriberto Rodriguez-Estrada, Elías Rodríguez-Segura, José Padilla-Medina, Juan Aguilera-Alvarez, and Juan Martinez-Nolasco. "Power Sharing Control in a Grid-Tied DC Microgrid: Controller Hardware in the Loop Validation." Applied Sciences 11, no. 19 (October 7, 2021): 9295. http://dx.doi.org/10.3390/app11199295.
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This article presents the development of a low-cost control hardware in the loop platform for the validation and analysis of controllers used for the management of power sharing between the main grid and a DC microgrid. The platform is made up of two parts: a main grid interconnection system emulator (MGISE) and a controller under test (CUT). The MGISE operates on a 260 V DC bus and includes a 1000 W photovoltaic array, a DC variable load and a single H full bridge converter (HFBC). The CUT includes a phase locked loop and a main cascade control structure composed of two PI controllers. Both the MGISE and the CUT were embedded on an NI myRIO-1900 development board and programmed using LabVIEW virtual instrumentation software. These devices communicate with each other using analog signals representing the AC side current, the DC side voltage, and the HFBC control signal. The MGISE operates with an integration time of 6 µs and its performance is validated by comparing it with a simulation in PSIM. The integration time of the MGISE, the development boards used, as well as its programming environment, and the results obtained from the comparison with PSIM simulation, show that the proposed platform is useful for the validation of controllers for power sharing, with a simple implementation process compared to other hardware description methods and with a low-cost platform.
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Davies-Jones, Robert, Vincent T. Wood, and Erik N. Rasmussen. "Doppler Circulation as a Fairly Range-Insensitive Far-Field Tornado Detection and Precursor Parameter." Journal of Atmospheric and Oceanic Technology 37, no. 6 (June 2020): 1117–33. http://dx.doi.org/10.1175/jtech-d-19-0116.1.
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AbstractFormulas are obtained for observed circulation around and contraction rate of a Doppler radar grid cell within a surface of constant launch angle. The cell values near unresolved axisymmetric vortices vary greatly with beam-to-flow angle. To obtain reliable standard measures of vortex strength we bilinearly interpolate data to points on circles of specified radii concentric with circulation centers and compute the Doppler circulations around and the areal contraction rates of these circles from the field of mean Doppler velocities. These parameters are proposed for detection of strong tornadoes and mesocyclonic winds. The circulation and mean convergence around the Union City, Oklahoma, tornado of 24 May 1973 are computed. After doubling to compensate for the unobserved wind component, the circulation (1.1 × 105 m2 s−1) agrees with a previous photogrammetric measurement. The mature tornado was embedded in a region, 6 km in diameter, of nearly uniform strong convergence (~5.5 × 10−3 s−1) without a simultaneous mesocyclone. A model of a convergent vortex inputted to a Doppler radar emulator reproduces these results. Moving the model vortex shows that for a WSR-88D with superresolution, the circulation is relatively insensitive to range and azimuth. WSR-88D data of the 31 May 2013 El Reno storm are also analyzed. The tornado formed in a two-celled mesocyclone with strong inflow 5 km away. In the next 8 min the circulation near the axis doubled and the areal contraction rate at 5 km increased by 50%. This signified a large probability of strong tornadoes embedded in powerful storm-scale winds.
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Zeng, Hong, Hui Liu, Jundong Zhang, Minglu Sun, and Tianjian Wang. "Design of Remote Upgrade System for Data Processing Unit in Marine Engine Room Simulator." Applied Sciences 12, no. 18 (September 10, 2022): 9107. http://dx.doi.org/10.3390/app12189107.
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With the development of ship intelligence, the frequency of upgrading the marine engine room simulator, which is essential for crew training, has increased. Traditionally, the data processing unit (DPU) of the marine engine room simulator is upgraded by manually downloading the firmware. This makes the hardware maintenance high-cost. In this paper, we first propose a WAN-based firmware upgrade system to enable secure over-the-air upgrades of DPUs and reduce operation and maintenance costs. A distributed hardware structure is given to manage DPU in the simulator via the Internet. We have designed two methods of firmware upgrades, automatic upgrades and remote upgrades. In automatic upgrades, the DPU can download new firmware upgrades from the web server through the router. By designing a series of mechanisms including code rollback, code backup and code confirmation, the In-Application Programming (IAP) technique is realized through the Internet. Firmware upgrades have good fault tolerance mechanisms to ensure that the emulator can still work in the event of an upgrade error. In remote upgrades, we upgrade the DPU firmware through the remote control center. We assessed the performance of the system by measuring the success rate of DPU upgrades, upgrade time and performance after the upgrade. The results show that the DPU upgrade success rate is close to 100% and performance is as good as expected. The results show that the remote firmware upgrade system proposed in this paper is reliable and practical.
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Holman, I. P., I. G. Dubus, J. M. Hollis, and C. D. Brown. "Using a linked soil model emulator and unsaturated zone leaching model to account for preferential flow when assessing the spatially distributed risk of pesticide leaching to groundwater in England and Wales." Science of The Total Environment 318, no. 1-3 (January 2004): 73–88. http://dx.doi.org/10.1016/s0048-9697(03)00375-9.
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YANG, WOOSEUNG, and CHONG-MIN KYUNG. "CONSCEP: A CONFIGURABLE SoC EMULATION PLATFORM FOR C-BASED FAST PROTOTYPING." Journal of Circuits, Systems and Computers 14, no. 01 (February 2005): 137–57. http://dx.doi.org/10.1142/s0218126605002210.
Full textAbstract:
FPGA-based emulation, which is now widely used in the design and verification of System-on-a-Chip (SoC), is applicable only when the RTL design for the whole system is available, thus resulting in a long design turn-around time. In this paper, we present a new design flow based on a C-to-hardware IMPLEmentation tool (CIMPLE) and a CONfigurable SoC Emulation Platform (CONSCEP) that emulates the on-chip bus system prior to the RTL design of each SoC component. With the emulation environment set up in the early stage of the design process, the design and verification task of each functional block in the SoC can be performed not only faster, but also more complete as a more complete set of test vectors can be applied before the integration. CONSCEP consists of (1) configurable bus components for the given on-chip bus standard and (2) a set of transactors to link the HDL models of the pre-verified IP blocks with the C models for the behavioral blocks to be designed, or software blocks. CIMPLE translates the C model for a hardware module to a SystemC code, which can be synthesized and directly attached to the CONSCEP as an IP. CIMPLE allows global variables, nested function calls, and simple pointer access, which significantly reduces the code migration. The proposed design flow is demonstrated using a JPEG encoder/decoder system and successfully applied to a commercial MPEG4 video codec chip.
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Othman, Nurul Azwa, and Hamdan Daniyal. "Investigation on Chassis Dynamometer with Capability to Test Regenerative Braking Function." International Journal of Power Electronics and Drive Systems (IJPEDS) 6, no. 3 (September 1, 2015): 657. http://dx.doi.org/10.11591/ijpeds.v6.i3.pp657-664.
Full textAbstract:
An investigation-based approach to a bidirectional power flow method for testing regenerative braking function on a chassis dynamometer is presented. The requirements and specifications for capability to test regenerative braking function of Electric Vehicle (EV) emulated by using a bidirectional chassis dynamometer are discussed. The dynamometer emulates road load conditions during testing, and regenerative braking is able to test their function while the vehicle is in deceleration condition. Performances of power requirement are illustrated and translated into sequence diagram. It is shown that the proposed topology is particularly advantageous in generating and regenerating power for energy consumption. The overview of conventional chassis dynamometer and the proposed chassis dynamometer is compared to investigate the parameter in the development of regenerative braking test.