A Software Package for the Modeling of Electrophysiological Activity Data

A complex of programs has been developed for computer modeling of multichannel time series recorded in various experiments on electromagnetic fields created by the human body. Sets of coordinates and directions of sensors for magnetic encephalographs of several types, electroencephalographs and magnetic cardiographs are used as models of devices. To study the human brain, magnetic resonance tomograms are used as head models; to study the heart, a body model in the form of a half-space with a flat boundary is used. The sources are placed in the model space, for them the direct problem is solved in the physical model corresponding to the device used. For a magnetic encephalograph and an electroencephalograph, an equivalent current dipole model in a spherical conductor is used, for a magnetic cardiograph, an equivalent current dipole model in a flat conductor or a magnetic dipole model is used. For each source, a time dependence is set and a multichannel time series is calculated. Then the time series from all sources are summed and the noise component is added. The program consists of three modules: an input-output module, a calculation module and a visualization module. The input-output module is responsible for loading device models, brain models, and field source parameters. The calculation module is responsible for directly calculating the field and transforming coordinates between the index system and the head system. The visualization module is responsible for the image of the brain model, the position of the field sources, a graphical representation of the amplitude-time dependence of the field sources and the calculated values of the total field. The user interface has been developed. The software package provides: interactive placement of field sources in the head or body space and editing of the amplitude-time dependence; batch loading of a large number of sources; noise modeling; simulation of low-channel planar magnetometers of various orders, specifying the shape of the device, the number of sensors and their parameters. Magnetic and electric fields produced by sources in the brain areas responsible for processing speech stimuli are considered. The resulting multichannel signal can be used to test various data analysis methods and for the experiment planning.

The electric substations compensating devices’ distribution optimization

The article discusses methods for calculating electrical networks when choosing the consumer compensating devices’ location. The main network and calculation module of a complex network is analyzed. The mathematical support of the reactive power factor compensation (PFC) problem is described in regional power systems, the areas of application of individual models are substantiated, and the results of the practical use of the corresponding calculation results are analyzed.

Benchmark Analysis on Loss-of-Flow-without-Scram Test of FFTF Using Refined SAC-3D Models

The Fast Flux Test Facility (FFTF) is a liquid sodium-cooled nuclear reactor designed by the Westinghouse Electric Corporation for the U.S. Department of Energy. In July 1986, a series of unprotected transients were performed to demonstrate the passive safety of FFTF. Among these, a total of 13 loss-of-flow-without scram (LOFWOS) tests were conducted to confirm the liquid metal reactor safety margins, provide data for computer code validation, and demonstrate the inherent and passive safety benefits of specific design features. In our preliminary work, we have performed relatively coarse modeling of the FFTF. To better predict the transient behavior of FFTF LOFWOS test #13, we modeled it using a more refined thermal-hydraulics model. In this paper, we simulate FFTF LOFWOS test #13 with the system safety analysis code SAC-3D according to the benchmark specifications provided by Argonne National Laboratory (ANL). The simulation range includes the primary and secondary circuits. The reactor core was modeled by the built-in 3D neutronics calculation module and the parallel-channel thermal-hydraulics calculation module. To better predict the reactivity feedback introduced by coolant level variations within the GEMs, a real-time macro cross-section homogenization processing module was developed. The steady-state power distribution was calculated as the transient simulation initial boundary conditions. In general, both the steady-state calculation results and the whole-plant transient behavior predictions are in good agreement with the measured data. The relatively large deviations in transient simulation occur in the outlet temperature predictions of the PIOTA in row 6. It can be preliminarily explained by the reason for neglecting the heat transfer between channels in this model.

Simulation and Experiment Analysis of 10 kV Flexible Grounding Device

The traditional 10 kV distribution network grounding system has some disadvantages, such as small grounding current and poor arc extinguishing effect, thus, hindering the detection of high-resistance grounding fault. Therefore, this paper studied the flexible grounding system consisting of small-resistance and active inverter in parallel. The control system comprises the compensation current calculation module, the fault detection module, and line protection strategy. During a single-phase grounding fault, the device is designed to inject a current of a given amplitude and phase into the neutral point to effectively suppress fault-point voltage and current and, meanwhile, quickly identifying the fault line or the busbar fault and then systematically protecting the distribution line. In addition, a large number of simulations have performed based on three grounding faults (metal, low-resistance, and high-resistance) and two modes (ungrounded and small-resistance grounding). The device can all be functional. Finally, a 400 V-level experimental prototype was built, and the experimental results are consistent with the simulation results, which can verify the effectiveness and feasibility of the flexible grounding device.

Coordinated Planning and Energy Conservation for Distribution Network with Renewable Energy: Standardized Information Model and Software

In recent years, energy conservation and environmental protection have attracted great attention by the state, and many efforts have been made from the policy and planning level. In view of the current distribution network planning requirements about energy-saving and environmental protection attributes such as loss reduction, carbon reduction, and environmental friendliness, this study proposes a set of energy-saving and environmental protection evaluation indicators for distribution network. Then, the CIM file library is constructed for typical equipment. Based on the CIM file, the digital planning technology for distribution network is designed. Besides, the feature library of energy conservation and environmental protection indicators, power flow calculation module, carbon flow calculation module, and renewable energy integration planning module are described.

INFORMATION MODELLING OF ENGINEERING NETWORKS FOR SUSTAINABLE WATER CONSUMPTION

The article based on information modelling considers one of the tasks of developing an automated solution for constructing computational schemes and specification materials for them for water supply and disposal – formation and programming of the calculation module of sustainable water consumption (construction of the computational scheme as a table).

JUSTIFICATION OF THE DESIGN SEQUENCE COMBINED SUPPORTS WITH VARIABLE CHARACTERISTICS

The article presents the sequence of calculating a combined support with variable parameters in the form of an algorithm. The application of the graphical editor of the CAE–system APM Win Shaft for modeling a rotor rotating in combined supports with variable characteristics is described. The results of the calculation module are presented. The obtained Kembel diagrams are considered. An analysis is given to the switching diagrams of a combined support with variable characteristics during operation in transient processes according to a certain algorithm. The presented algorithm eliminates the possibility of increasing the amplitude of oscillations when passing through critical frequencies. Conclusions are drawn about the effectiveness of using the specified sequence of calculations Recommendations are given on the use of the proposed calculation sequence for the design of similar combined supports with variable characteristics.