Connection Scheme Research Articles

Experimental study and design methodology of sacrificial-energy dissipation beam-column joint

To enable secondary energy-dissipation components to actively attract and dissipate seismic energy, a new type of sacrificial-energy dissipation beam-column joint (SEDJ) was proposed. This study validates the performance of the proposed SEDJ through full-scale quasi-static loading tests. The rotation angle of the proposed SEDJ at the beam end, corresponding to the peak strength Fu, can be controlled within 1/250 - 1/50. In addition, the beam and column components remain elastic, thereby achieving the seismic performance objectives of "no damage, sacrificial-energy dissipation, and no collapse under service-level (SLE), design-basis (DBE), and maximum-considered (MCE) earthquakes", respectively. This study enhances the design of the SEDJ by adopting a built-in sleeve connection scheme to significantly reduce the free-stroke displacement, and a double-coupling block scheme to solve the issue of stress concentration in friction plates that leads to cracking. Furthermore, the efficiency of the installation and disassembly of friction plates is improved, thus enabling the rapid replacement of bolts and friction plates after strong earthquakes. Finally, a practical engineering design methodology is proposed that decouples the bending moments of the sacrificial MR and energy-dissipation MS stages, this methodology activates the sacrificial mechanism under DBEs or MCEs to protect primary beam and column components, and will provide potential insights for the development and application of innovative structural components based on the sacrificial mechanism design philosophy.

USE OF A TWO-STAGE COMBINED SCHEME FOR HEAT EXCHANGERS CONNECTION IN HEATING POINTS FOR HOT WATER SUPPLY OF INSULATED BUILDINGS

The article addresses the features of the functioning of centralised heat supply systems of residential micro-districts considering the improvement of thermal insulation of existing buildings. It also analyses the performance characteristics of hot water supply heaters installed on individual heat points of insulated buildings. The authors compared the heat transfer surface area of heaters and network water flow rate through the heating point for one-stage and two-stage combined schemes of connection of heat exchangers and heat networks. The analysis of calculation results showed that using a two-stage combined connection scheme reduces the consumption of network water through the individual heat supply unit compared to the one-stage scheme. However, the two-stage scheme causes the necessity to increase the heat transfer surface area compared to the one-stage connection scheme. We generalised the results by formulas for calculating water flow rate from distribution heat networks and heat transfer surface area. It is possible to use the obtained results to develop a strategy for reforming micro-district centralised heating systems. Using a two-stage combined connection scheme for hot water supply heat exchangers installed on individual heating points (IHP) of additionally insulated buildings reduces network water consumption through the individual heating point by 8–16% compared to a one-stage connection scheme. The device of a two-stage combined scheme in comparison with a one-stage scheme causes the increase of heat transfer surface area of heat exchangers of the hot water supply of individual heating points from one and a half to two times depending on the accepted design temperature of heating of cold water at the first stage of the heating unit. The results of calculations are approximated by equations, allowing, with acceptable accuracy, to compare the indicators of two-stage combined and one-stage schemes of connection of water heaters for individual heating points of insulated buildings. Keywords: centralised heat supply, individual heating point, water heaters, hot water supply.

Rapid assembly bolt connection design method for TBM disc cutter box based on AHP

With the TBM disc cutter box as the subject of investigation, this study addresses the intricate and labor-intensive nature of the assembly process in TBM disc cutter box welding assembly. In order to expedite the assembly of the cutter-head and disc cutter box, an alternative approach utilizing combined bolt connections is implemented in place of welding assembly. Therefore, this article proposes a TBM disc cutter combination bolt connection design method based on AHP. Initially, a hierarchical analysis model is constructed, taking into account the actual conditions of the TBM disc cutter box combined bolt connections. Subsequently, from the array of factors influencing bolted connection performance, five experimental variables were chosen, and an orthogonal experimental layout was devised to examine the stress dispersion in the TBM disc cutter box under conditions of bolted assembly, employing finite element analysis. By conducting extreme difference analysis, the study examined the effects of each experimental factor on the bolt connection performance, and determined the order of importance of each factor more objectively. Thus, the comprehensive weights of each factor were calculated, and the optimal solution of the bolt connection scheme was selected by synthesizing the effects of multiple factors.

SaraNet: Semantic aggregation reverse attention network for pulmonary nodule segmentation

Accurate segmentation of pulmonary nodule is essential for subsequent pathological analysis and diagnosis. However, current U-Net architectures often rely on a simple skip connection scheme, leading to the fusion of feature maps with different semantic information, which can have a negative impact on the segmentation model. In response to this challenge, this study introduces a novel U-shaped model specifically designed for pulmonary nodule segmentation. The proposed model incorporates features such as the U-Net backbone, semantic aggregation feature pyramid module, and reverse attention module. The semantic aggregation module combines semantic information with multi-scale features, addressing the semantic gap between the encoder and decoder. The reverse attention module explores missing object parts and captures intricate details by erasing the currently predicted salient regions from side-output features. The proposed model is evaluated using the LIDC-IDRI dataset. Experimental results reveal that the proposed method achieves a dice similarity coefficient of 89.11%and a sensitivity of 90.73 %, outperforming state-of-the-art approaches comprehensively.

Considering the reliability of gas supply to power plants in the analysis of electric power system adequacy

One of the promising directions for further development of the methodology for investigating and ensuring the reliability of energy systems is the consideration of integrated energy systems. This is caused by the need for the adequate reflection of their joint operation. Previously, the authors proposed several methodological approaches based on "node," "system," and "evaluation" to assess the adequacy of an electric power system when this is operating jointly with a gas supply system. In that case, the focus was made only on high-pressure gas supply systems (simplified calculation). This work aims to consider not only the high-pressure gas systems, but also to take into account the influence of lowpressure gas systems (refined calculation) on the adequacy of electric power system. This approach appears to be more technologically advanced and corresponds to the real conditions of the functioning of integrated power systems. The studies were carried out using the “node” approach, its reference calculation being the most accurate one. The methods applied in the research are probability theory and mathematical statistics: a particular theorem on the repetition of experiments (Bernoulli's trial), calculation of probability distribution series, theorems of addition and multiplication of probabilities. A comparative analysis of reference calculations of the electric power system adequacy was carried out for simplified and refined connection schemes in the gas system (two cases were considered: a highly reliable low-pressure gas system and a low-reliability one). The calculations were performed on an illustrative example of a power system. Assessment of the load supply reliability in integrated systems must factor in the process features of the systems at issue, the block diagram of their connections, as well as the accuracy of the results obtained and the complexity of searching and preparing initial data for the corresponding research model.

(Invited) Advanced Compute Scaling: A New Era of Exciting, Sustainability-Aware Innovations with Nanosheet-Based Devices, Increased Interdisciplinary Synergies, and (R)Evolution Towards Higher Versatility

We report on several key elements for enabling advanced compute scaling. At transistor level, as we are entering the nanosheet (NS) era, the focus lies on single-level NSFETs consisting of several vertically stacked NS per device, which can evolve into 3D stacked configurations like the so-called complementary FET (CFET) with potentially different materials/crystal orientations for the stacked channels. New device connectivity schemes are also becoming possible thanks to the trend towards using both wafer sides, started with the move of on-chip power distribution to the wafer’s backside. As devices are becoming sandwiched and accessed from levels above and below them, that also allows interesting new opportunities for transistor engineering, some examples of which will be discussed here. In parallel, from a system level’s perspective, a (r)evolution towards smart disintegration, enabling higher flexibility and hybridized technology platforms, is expected to further allow new scaling paths, also as it can help ease the introduction of new materials and device architectures.

Optimum embedment depths for CFST column-to-foundation connections: Analytical and reliability-based approach

In the present study, the pullout capacity models were developed to derive analytical expressions for the minimum required depths of embedment for conventional and two recently published schemes of connection for circular and square concrete-filled steel tubular (CFST) columns. The models were developed by equating the pullout strength of the tube with the pullout capacity of the reinforced concrete (RC) footing. The pullout capacity of the RC footing was a function of the strength of cement grout, footing concrete, and RC footing reinforcement. The analytical expressions derived for the minimum required depths of embedment were utilized to deduce limit state functions. These limit state functions were then employed for the reliability calculations by means of the Monte Carlo Simulation (MCS) technique. The reliability calculations provide optimum embedment depths for CFST columns for the given reliability level. It was shown for the required reliability index of 3.0, the requirements of nominal embedment depth for the second column-to-foundation connecting scheme for circular and square CFST columns are 37.3% and 45.2% less than their corresponding first schemes of connection. This outcome proves the superiority of the second scheme (as a result of mechanical interlocking) over the first scheme. A few parametric studies were also conducted to obtain results of practical value.

Seismic Performance Evaluation of Traditional Chinese Mortise-Tenon Frame Infilled with Friction Dissipative Window Frame

ABSTRACT This paper presents a new form of window frame that employs a friction dissipative connection. The design is informed by a structural analysis of the sill window in traditional wooden structures and inspired by friction dissipative mechanisms. By considering the frictional wear of the friction block, a more accurate formula for calculating the frictional torque is derived and its accuracy is verified. Additionally, a finite element model of the sill window-wooden frame system is established and verified using experimental data. Then a further finite element model of the sill window-wooden frame system with the friction dissipative window frame is established and analyzed, and the effectiveness of the reinforcement scheme of the friction dissipative connection is verified. The analysis shows that compared to the sill window-wooden frame system, the load-carrying capacity and energy dissipation of the sill window-wooden frame reinforced with the friction dissipative window frame are significantly improved. When the bolt pre-tightening force is 100 kN, the peak load and stiffness of the sill window-wooden frame system reinforced with the friction energy dissipation window frame are increased by 2.7 and 2.57 times, respectively, compared to the sill window-wooden frame, which can effectively prevent the seismic damage of ancient wooden structures.

Enhancing electromagnetic compatibility and energy efficiency of electric vehicle charging stations

Problem. The article proposes a single-link structure for an electric vehicle charging station utilizing an active four-square rectifier with power factor correction. A Matlab model of the proposed charging station is developed, taking into account parameters such as the power network, the switches of the active rectifier, its automatic control system, and an equivalent model of the battery compartment. Additionally, a mathematical model for calculating static and dynamic losses is created based on polynomial approximation of the energy dependencies of IGBT modules. The analysis investigates power quality parameters, components of energy losses, and efficiency of the charging station across various charge currents and PWM frequencies during a full battery charge interval. Goal. The aim of this study is to propose a single-link structure for an electric vehicle charging station using an active four-square rectifier with power factor correction. It includes an analysis of power quality parameters, components of energy losses, and efficiency of the charging station at different charge currents and PWM frequencies during a full battery charge interval. Methodology. To achieve the goal, several key steps are considered. These include theoretical substantiation of the scheme of the electric microgrid charging station for electric vehicles with one-stage energy conversion, analysis of the battery connection scheme in the Tesla Model S electric car, research and calculation of efficiency, modeling of the charging station, development of a Matlab model of a microgrid system for the charging station, SAC analysis of battery charge voltage and current of a three-phase AV with PWM, modeling of losses in IGBT modules by polynomial approximation of dependencies, distribution of losses in the charging station system, and analysis of energy efficiency parameters. Results. The study presents the energy efficiency parameters of an external DC EV charging station using an active rectifier. It reveals that maximum efficiency of the system is achieved at minimum charge current. However, decreasing the charge current prolongs the charge process and slightly affects power quality parameters. Originality. A mathematical model for calculating static and dynamic losses was developed based on polynomial approximation of the energy dependencies of IGBT modules. The analysis encompasses power quality parameters, components of energy losses, and efficiency of the charging station across various charge currents and PWM frequencies during a full battery charge interval. Practical value. This study contributes to the further development of electric vehicles by improving the energy indicators of electric vehicle batteries and converters of electric vehicle charging stations, enabling fast charging modes. Active development is observed in each of these directions.

Internal capacitive compensation of the reactive power of the screw electromechanical converter

Introduction. A special category among induction machines with a massive rotor is occupied by the class of multifunctional electromechanical energy converters, which are integrated with the links of technological processes Problem. The exchange of reactive energy between the source and the electromechanical converter during periods of operation with a low load leads to a significant decrease in its efficiency and power factor. With the use of non-linear loads and taking into account possible resonance, it has become more difficult to improve the power factor by installing capacitor banks. Goal. Increasing the energy indicators of the electromechanical converter by spatial displacement of the main and additional stator windings and internal capacitive compensation. Methodology. Comparative analysis of connection schemes and spatial arrangement of stator windings when using internal capacitive compensation. Modeling and experimental studies of electromagnetic and electromechanical characteristics of a screw electromechanical converter. Results. The distribution of electromagnetic quantities was established and the choice of the angle of spatial displacement of the main and additional windings of the stator phases of the modified converter, which ensure an increase in the value of the electromagnetic torque and power factor, was justified. The results of experimental studies of the screw electromechanical converter are presented. Originality. For the first time, a method of internal capacitive compensation of reactive power is proposed for multifunctional electromechanical converters of technological purpose. Practical value. The use of the proposed method of spatial displacement of the main and additional stator windings and internal capacitive compensation will ensure an increase in the energy performance of the screw electromechanical converter. References 23, tables 3, figures 15.

Enabling Fast and Privacy-Preserving Broadcast Authentication With Efficient Revocation for Inter-Vehicle Connections

Many vehicular applications, especially safety-related ones, rely on spatial-temporal messages periodically broadcast by vehicles. In the absence of a secure authentication scheme, invalid spatial-temporal messages may be sent out by malicious vehicles. Meanwhile, malicious applications may also collect a lot of personal information from spatial-temporal messages. Since inter-vehicle connections are often deployed in high-moving traffic, any authentication must be implemented in real-time. To meet all these properties, we propose a Fast and Anonymous Spatial-Temporal Trust (FastTrust) scheme for inter-vehicle connections. In contrast to most authentication protocols which rely on fixed infrastructures, FastTrust is mostly designed on hash chains and an entropy-based commitment, and is able to secure periodic spatial-temporal messages. FastTrust also protects vehicles' privacy by deploying a pseudonym-varying scheduling mechanism to satisfy the anonymity and unlinkability requirements. Finally, in order to efficiently isolate malicious vehicles, a lightweight certificate management scheme is proposed for the limited bandwidth of vehicular networks. We provide analytical evaluations to show that our FastTrust achieves the security and privacy properties. Extensive validations are done to show that FastTrust can authenticate dozens of times faster than the existing signature algorithms, and isolate malicious vehicles at a low cost in terms of communication and computational resources.

Novel coarse and fine stage parallel vibration isolation pointing platform for space optics payload

A coarse and fine parallel vibration isolation pointing platform (CFPP) is proposed, which can realize a wide range of motion and active vibration isolation for space optical payload. First the coarse and fine parallel connection scheme is designed based on the Stewart generalized configuration. Kinematic and constraint analyses are performed to determine the two operation modes of the platform. The platform is then structurally designed. System dynamics model is established based on the Lagrange method, and the dynamic disturbance characteristics are analyzed. Next, the active vibration isolation control algorithm based on H∞ loop shaping is designed. The stability of the control system is analyzed. Finally, the prototype is constructed, and the three-axis pointing range test and active vibration isolation experiments in four attitudes are carried out, and the experimental results show that the designed pointing vibration isolation system with coarse and fine stages in parallel can achieve a 7° movement range of the three axes, and it has a maximum vibration isolation capacity of 20 dB for the disturbance in the frequency band of 2–20 Hz. It has great application prospects in the direction of miniaturization and integration of space optical payload in the future.

Semantic Complete Scene Forecasting from a 4D Dynamic Point Cloud Sequence

We study a new problem of semantic complete scene forecasting (SCSF) in this work. Given a 4D dynamic point cloud sequence, our goal is to forecast the complete scene corresponding to the future next frame along with its semantic labels. To tackle this challenging problem, we properly model the synergetic relationship between future forecasting and semantic scene completion through a novel network named SCSFNet. SCSFNet leverages a hybrid geometric representation for high-resolution complete scene forecasting. To leverage multi-frame observation as well as the understanding of scene dynamics to ease the completion task, SCSFNet introduces an attention-based skip connection scheme. To ease the need to model occlusion variations and to better focus on the occluded part, SCSFNet utilizes auxiliary visibility grids to guide the forecasting task. To evaluate the effectiveness of SCSFNet, we conduct experiments on various benchmarks including two large-scale indoor benchmarks we contributed and the outdoor SemanticKITTI benchmark. Extensive experiments show SCSFNet outperforms baseline methods on multiple metrics by a large margin, and also prove the synergy between future forecasting and semantic scene completion.The project page with code is available at scsfnet.github.io.

Exploring Jahn-Teller distortions: a local vibrational mode perspective

The characterization of normal mode (CNM) procedure coupled with an adiabatic connection scheme (ACS) between local and normal vibrational modes, both being a part of the Local Vibrational Mode theory developed in our group, can identify spectral changes as structural fingerprints that monitor symmetry alterations, such as those caused by Jahn-Teller (JT) distortions. Employing the PBE0/Def2-TZVP level of theory, we investigated in this proof-of-concept study the hexaaquachromium cation case, [Cr(OH2)6]3+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$[\ ext {Cr}{(\ ext {OH}_{2})}_{6}]^{3+}$$\\end{document}/[Cr(OH2)6]2+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$[\ ext {Cr}(\ ext {OH}_{2})_{6}]^{2+}$$\\end{document}, as a commonly known example for a JT distortion, followed by the more difficult ferrous and ferric hexacyanide anion case, [Fe(CN)6]4-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$[\ ext {Fe}{(\ ext {CN})}_{6}]^{4-}$$\\end{document}/[Fe(CN)6]3-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$[\ ext {Fe}{(\ ext {CN})}_{6}]^{3-}$$\\end{document}. We found that in both cases CNM of the characteristic normal vibrational modes reflects delocalization consistent with high symmetry and ACS confirms symmetry breaking, as evidenced by the separation of axial and equatorial group frequencies. As underlined by the Cremer-Kraka criterion for covalent bonding, from [Cr(OH2)6]3+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$[\ ext {Cr}{(\ ext {OH}_{2})}_{6}]^{3+}$$\\end{document} to [Cr(OH2)6]2+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$[\ ext {Cr}{(\ ext {OH}_{2})}_{6}]^{2+}$$\\end{document} there is an increase in axial covalency whereas the equatorial bonds shift toward electrostatic character. From [Fe(CN)6]4-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$[\ ext {Fe}{(\ ext {CN})}_{6}]^{4-}$$\\end{document} to [Fe(CN)6]3-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$[\ ext {Fe}{(\ ext {CN})}_{6}]^{3-}$$\\end{document} we observed an increase in covalency without altering the bond nature. Distinct π\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\pi $$\\end{document} back-donation disparity could be confirmed by comparison with the isolated CN-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ ext {CN}^{-}$$\\end{document} system. In summary, our study positions the CNM/ACS protocol as a robust tool for investigating less-explored JT distortions, paving the way for future applications.Graphical abstractThe adiabatic connection scheme relates local to normal modes, with symmetry breaking giving rise to axial and equatorial group local frequencies

Meeting economic and social viability goals in regional airline schemes through hub-and-spoke network connectivity

AbstractWe examine the viability of regional connectivity schemes by considering both social and economic objectives. In India the scheme is called UDAN (loosely translated affordable air travel) which is designed to include economically backward communities in India into the air travel grid. Using secondary data sources from the airline sector in India, and qualitative interviews of knowledgeable personnel in the airline industry, we demonstrate the importance of hub-and-spoke network design in comparison to point-to-point connectivity for regional connectivity networks. Specifically, we develop Viable Hub Location Problem for Regional Connectivity (VHLPRC) for resilience and sustainability through bilevel optimization with single leader and two independent followers. We test our proposed approach using datasets from USA and India. Our analyses suggest strategically choosing primary hubs and re-routing traffic through regional hubs for long-term commercial viability or survivability of regional connectivity schemes. The introduction of regional hubs had mixed effects. On the positive side, it improved reach, albeit at considerable (hidden) costs. On the negative side, several sub-programs had to be abandoned for a variety of reasons, including lack of demand traffic. The lessons learned from this study inform policy makers, academics, and practicing managers on how to remain viable and sustain operations in regional connectivity schemes. With the introduction of social variables, commercial viability has been shown to face specific real-life challenges. An attempt to help solve these problems is also presented in this paper through risk reduction, capacity augmentation, and by continuing fare subsidies.

Structure and function of the hippocampal CA3 module

The hippocampal formation is crucial for learning and memory, with submodule CA3 thought to be the substrate of pattern completion. However, the underlying synaptic and computational mechanisms of this network are not well understood. Here, we perform circuit reconstruction of a CA3 module using three dimensional (3D) electron microscopy data and combine this with functional connectivity recordings and computational simulations to determine possible CA3 network mechanisms. Direct measurements of connectivity schemes with both physiological measurements and structural 3D EM revealed a high connectivity rate, multi-fold higher than previously assumed. Mathematical modelling indicated that such CA3 networks can robustly generate pattern completion and replay memory sequences. In conclusion, our data demonstrate that the connectivity scheme of the hippocampal submodule is well suited for efficient memory storage and retrieval.

Influence of asymmetric-paths winding on electromagnetic force of variable speed pump storage generator-motor

Stator asymmetric-paths winding of variable speed pump storage (VSPS) generator-motor can solve the problem of mismatch of unit speed, capacity and outlet voltage. However, different winding connection schemes will lead to the change of magnetomotive force (MMF) asymmetry of each branch, and then affect the electromagnetic force of generator-motor. In order to explore the effect of this winding type on the electromagnetic force, stator asymmetric-paths winding's MMF and electromagnetic force of 336 MW VSPS generator-motor is derived. Waveforms and harmonic contents of the stator asymmetric-paths winding MMF of the equal-pitch and unequal-pitch schemes are analyzed. Under the consideration constraints of factors such as minimizing MMF asymmetry and electromagnetic vibration, a reasonable asymmetric-paths winding scheme with unequal pitch is determined It is concluded that asymmetric-paths winding scheme with pitch of 14-15-16 can effectively weaken the low-order MMF harmonics and reduce the electromagnetic force under the limitation of asymmetric-paths winding form. The finite element model of VSPS generator-motor is further developed, and the electromagnetic force amplitude and spatial and temporal distribution characteristics under 6 winding schemes are calculated to verify the accuracy of the calculation model. The results of the study can provide technical support for the development of localized VSPS generator-motor.

EDDS-Unet: An Encoder-Decoder Double Skip Connection Scheme for Skin Lesion Segmentation

The paper presents an approach for effective skin lesion segmentation from dermatoscopic images. Aiming at transferring the weights trained from a network originally designed for image classification task, this study proposes to utilize the first layers of EfficientNet as the encoding layers of a U-Net based architecture. Besides, we introduce an encoder-decoder double skip connection scheme, a new skip connection architecture for extracting useful spatial details of skin lesions from the encoding layers. By the double skip scheme, the approach not only fuses information from the encounter layer in the encoder path to the corresponding layer in the decoder path, but also takes into account information of the proceeding encoding layer. In addition, we propose a new decoder network using the Residual blocks and Convolutional Block Attention Module (CBAM) blocks to handle the gradient vanishing problem as well as penalize the weight of each layer. The proposed Encoder-Decoder Double Skip with the Unet architecture, namely EDDS-Unet, has shown promising performance when evaluated on the official ISIC 2017 challenge and the PH2 databases. The proposed method achieves high evaluation scores with the Dice Similarity Coefficients of 0.907 for the ISIC 2017 and 0.950 for the PH2 databases without pre-or post-processing steps.

CubeSat standardized modular assembly method and design optimization

In order to solve the deficiencies of traditional board-level assembly CubeSat, such as low modularity, complex assembly process and poor scalability, a sandwich module assembly structure and method with no drive components is proposed, which can achieve quick connection and flexible assembly between modules. First, the proposed CubeSat standard module can be compatible with the standard interface of traditional CubeSat. The 4-in-1 interface of Mechanical-Electrical-Thermal-Data does not occupy the internal space of the standard module, and the electrical and thermal interfaces meet the requirements of CubeSat in-orbit work. Secondly, in order to improve the reliability of the connection between the modules, a plug-in connection scheme of the mechanical interface was designed. Finally, a genetic algorithm was used to optimize the interface size, so that it has better plug-in performance. The simulation results show that the performance of the male interface of titanium alloy material is the best, and the error between the finite element analysis and genetic algorithm results is less than 4.8 %, which is consistent with the actual tensile test results of the optimized prototype, and meets the mechanical requirements of the launch process and space orbit operation for CubeSat. The test results can guide production and provide a reference for subsequent engineering applications of CubeSat modular assembly.

FEATURES OF THE FUNCTIONING OF SMALL POWER SOLAR GENERATION IN THE IPS OF UKRAINE UNDER THE CONDITIONS OF THE GREEN TRANSFORMATION

Within the framework of the transformation of the energy system in terms of ensuring the further development of small distributed generation from renewable energy sources, a new support model for low-power facilities is proposed, which will facilitate the commissioning of new generation entities. In the paper, research is conducted on the problem of small generation in Ukraine, which is faced by the power system, in the conditions of an increase in the share of distributed generation. An assessment of the impact of small solar power plants on the operation of the electrical network, including rooftop ones installed in households, was carried out. Typical schemes of connection of SPPs to the electrical network are considered and their influence on electrical equipment, elements of power supply systems and principles of operation are determined. It has been established that the integration of new renewable energy entities, including low-power SPPs, causes a number of technical problems that have an impact on the operational characteristics of the network, security of supply, and reliability. The main ways of solving the problems of losses and deviations of the voltage level in distribution networks, when connecting small SPPs, have been formed. In further research, the obtained results will be used to develop proposals for connecting low-power entities to the electric network and their formalization in the form of provisions of regulatory and technical documents.