Advanced Systems Engineering: Theory and Applications

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
Applied Sciences applsci	2.5	5.3	2011	17.8 Days	CHF 2400
Sensors sensors	3.4	7.3	2001	16.8 Days	CHF 2600
Electronics electronics	2.6	5.3	2012	16.8 Days	CHF 2400
Metals metals	2.6	4.9	2011	16.5 Days	CHF 2600
Energies energies	3.0	6.2	2008	17.5 Days	CHF 2600
Chips chips	-	-	2022	15.0 days *	CHF 1000

19 pages, 2861 KiB

Open AccessArticle

Finite-Time Adaptive Dynamic Surface Asymptotic Tracking Control of Uncertain Multi-Agent Systems with Unknown Control Gains

by Xiongfeng Deng and Chaocheng An

Appl. Sci. 2023, 13(17), 9552; https://doi.org/10.3390/app13179552 - 23 Aug 2023

Viewed by 1035

Abstract

In this work, the finite-time asymptotic tracking control problem of uncertain multi-agent systems with unknown control gains is studied. For the unknown control gain of each subsystem in multi-agent systems, we consider using the Nussbaum gain function techniques to handle them. To deal [...] Read more.

In this work, the finite-time asymptotic tracking control problem of uncertain multi-agent systems with unknown control gains is studied. For the unknown control gain of each subsystem in multi-agent systems, we consider using the Nussbaum gain function techniques to handle them. To deal with the unknown uncertain nonlinear dynamics, the radial basis function neural network is introduced in each step of the dynamic surface control design. In addition, a nonlinear compensating term with the estimation of an unknown bounded parameter is designed to avoid repeated differentiation of each virtual control law. Then, based on the neural network control method, dynamic surface control technique, and finite-time control theory, an adaptive neural network finite-time dynamic surface control law is finally designed. Using stability analysis, it is proven that the presented adaptive control law can guarantee all signals of the closed-loop system semi-global practical finite-time stable, and the tracking error of each follower agent can converge to a small neighborhood of zero in finite time. Finally, a class of single-link robot systems is provided to illustrate the effectiveness of the designed control law. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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15 pages, 18198 KiB

Open AccessArticle

A Formal Approach to the Extraction of Permittivity and Permeability of Isotropic and Anisotropic Media Using the TM₁₁ Mode in Rectangular Waveguides

by Waldemar Susek, Andrzej Dukata and Patrycja Pomarańska

Electronics 2023, 12(13), 2899; https://doi.org/10.3390/electronics12132899 - 1 Jul 2023

Cited by 2 | Viewed by 1325

Abstract

Based on our previous work on the propagation of electromagnetic waves in a layered medium placed in a rectangular waveguide, we present the theory of using the TE₁₀ and TM₁₁ modes to determine the complex parameters of isotropic and anisotropic media. [...] Read more.

Based on our previous work on the propagation of electromagnetic waves in a layered medium placed in a rectangular waveguide, we present the theory of using the TE₁₀ and TM₁₁ modes to determine the complex parameters of isotropic and anisotropic media. The Nicolson–Ross–Weir method was used. The cases of isotropic, uniaxial, and biaxial materials were considered. It has been shown that the TM₁₁ mode can be used to extract parameters of non-magnetic uniaxial anisotropy media by a single measurement, without changing the sample position. This is not possible with the previously used TE₁₀ mode. It is also possible to use the TM₁₁ mode to quickly determine whether a material is isotropic or not. Experimental results are presented for some isotropic materials. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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13 pages, 5712 KiB

Open AccessCommunication

Modelling Polarization Effects in a CdZnTe Sensor at Low Bias

by Jindřich Pipek, Roman Grill, Marián Betušiak and Kris Iniewski

Sensors 2023, 23(12), 5681; https://doi.org/10.3390/s23125681 - 17 Jun 2023

Viewed by 1637

Abstract

Semi-insulating CdTe and CdZnTe crystals fabricated into pixelated sensors and integrated into radiation detection modules have demonstrated a remarkable ability to operate under rapidly changing X-ray irradiation environments. Such challenging conditions are required by all photon-counting-based applications, including medical computed tomography (CT), airport [...] Read more.

Semi-insulating CdTe and CdZnTe crystals fabricated into pixelated sensors and integrated into radiation detection modules have demonstrated a remarkable ability to operate under rapidly changing X-ray irradiation environments. Such challenging conditions are required by all photon-counting-based applications, including medical computed tomography (CT), airport scanners, and non-destructive testing (NDT). Although, maximum flux rates and operating conditions differ in each case. In this paper, we investigated the possibility of using the detector under high-flux X-ray irradiation with a low electric field satisfactory for maintaining good counting operation. We numerically simulated electric field profiles visualized via Pockels effect measurement in a detector affected by high-flux polarization. Solving coupled drift–diffusion and Poisson’s equations, we defined the defect model, consistently depicting polarization. Subsequently, we simulated the charge transport and evaluated the collected charge, including the construction of an X-ray spectrum on a commercial 2-mm-thick pixelated CdZnTe detector with 330 µm pixel pitch used in spectral CT applications. We analyzed the effect of allied electronics on the quality of the spectrum and suggested setup optimization to improve the shape of the spectrum. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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40 pages, 9697 KiB

Open AccessArticle

Modelling and Experimental Study of Power Losses in Toothed Wheels

by Guglielmo Giannetti, Enrico Meli and Andrea Rindi

Sensors 2023, 23(12), 5541; https://doi.org/10.3390/s23125541 - 13 Jun 2023

Cited by 1 | Viewed by 1080

Abstract

In recent decades, the request for more efficient performances in the aeronautical sector moved researchers to pay particular attention to all the related mechanisms and systems, especially with respect to the saving of power. In this context, the bearing modeling and design, as [...] Read more.

In recent decades, the request for more efficient performances in the aeronautical sector moved researchers to pay particular attention to all the related mechanisms and systems, especially with respect to the saving of power. In this context, the bearing modeling and design, as well as gear coupling, play a fundamental role. Moreover, the need for low power losses also concerns the study and the implementation of advanced lubrication systems, especially for high peripheral speed. With the previous aims, this paper presents a new validated model for toothed gears, added to a bearing model; with the link of these different submodels, the whole model describes the system’s dynamic behavior, taking into account the different kinds of power losses (windage losses, fluid dynamic losses, etc.) generated by the mechanical system parts (especially rolling bearings and gears). As the bearing model, the proposed model is characterized by high numerical efficiency and allows the investigation of different rolling bearings and gears with different lubrication conditions and frictions. A comparison between the experimental and simulated results is also presented in this paper. The analysis of the results is encouraging and shows a good agreement between experiments and model simulations, with particular attention to the power losses in the bearing and gears. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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20 pages, 740 KiB

Open AccessArticle

Dual-Arm Cluster Tool Scheduling for Reentrant Wafer Flows

by Tairan Song, Yan Qiao, Yunfang He, Naiqi Wu, Zhiwu Li and Bin Liu

Electronics 2023, 12(11), 2411; https://doi.org/10.3390/electronics12112411 - 26 May 2023

Cited by 3 | Viewed by 1316

Abstract

Cluster tools are the key equipment in semiconductor manufacturing systems. They have been widely adopted for many wafer fabrication processes, such as chemical and physical vapor deposition processes. Reentrant wafer flows are commonly seen in cluster tool operations for deposition processes. It is [...] Read more.

Cluster tools are the key equipment in semiconductor manufacturing systems. They have been widely adopted for many wafer fabrication processes, such as chemical and physical vapor deposition processes. Reentrant wafer flows are commonly seen in cluster tool operations for deposition processes. It is very complicated to schedule cluster tools with reentrant processes. For a dual-arm cluster tool with two-time reentering, the existing studies point out that a one-wafer periodical (1-WP) schedule can be found, and it is optimal in terms of productivity. However, for some wafer fabrication processes, wafers should be processed at some PMs more than two times. This gives rise to a question of whether there still exists a 1-WP schedule for dual-arm cluster tools with the number of reentering times being more than two such that the cycle time of a tool can reach the lower bound. This problem is still open, and this is what this work wants to tackle. For a dual-arm cluster tool with the number of reentering times being k (>2) times, if there does not exist a value f ∈ {1, 2 …} such that k = 3f, theoretical proofs are given to show that a 1-WP schedule can be found, otherwise it does not exist. For cases with a 1-WP schedule, the cycle time can be obtained by analytical expressions. For the cases without a 1-WP schedule, two new methods for a three-wafer periodical schedule are proposed to improve the system productivity by comparing it with an existing three-wafer periodical schedule. The applications of the obtained results are demonstrated by examples. Wafer residency time constraints are required for some wafer fabrication processes. Note that the results obtained in this work cannot be directly applied to cluster tools with both reentrant wafer flows and wafer residency time constraints. Nevertheless, schedulablity and scheduling analyses for that applications can be conducted based on the obtained results in this work. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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16 pages, 4368 KiB

Open AccessArticle

A Requirement Quality Assessment Method Based on User Stories

by Xiangqian Xu, Yajie Dou, Liwei Qian, Zhiwei Zhang, Yufeng Ma and Yuejin Tan

Electronics 2023, 12(10), 2155; https://doi.org/10.3390/electronics12102155 - 9 May 2023

Cited by 5 | Viewed by 2028

Abstract

Agile development processes based on user stories often face issues such as incomplete, inconsistent, and inaccurate user requirements, which increase the workload of agile development teams and reduce the efficiency of product function development, ultimately resulting in the inability to respond quickly to [...] Read more.

Agile development processes based on user stories often face issues such as incomplete, inconsistent, and inaccurate user requirements, which increase the workload of agile development teams and reduce the efficiency of product function development, ultimately resulting in the inability to respond quickly to user requirements. This paper proposes a user requirement quality assessment method based on user stories to address these problems. This method relies on the agile development process, constructs a user requirement quality assessment framework, defines a user story model and a user requirement quality model, develops seven user requirement quality assessment criteria, and designs a user requirement quality assessment process. A data experiment exploring the development of smartphone requirements is used to validate the feasibility and effectiveness of the method. The experimental results demonstrate that the method improves user requirement quality to some extent, providing an automated solution for agile development teams to enhance user requirement quality. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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17 pages, 1627 KiB

Open AccessArticle

Channel Emulator Framework for Underwater Acoustic Communications

by Indrakshi Dey and Nicola Marchetti

Appl. Sci. 2023, 13(9), 5818; https://doi.org/10.3390/app13095818 - 8 May 2023

Cited by 1 | Viewed by 1628

Abstract

In this paper, we develop a tractable mathematical model and an emulation framework for communicating information through water using acoustic signals. Water is considered one of the most complex media to model due to its vastness and variety of characteristics, which depend on [...] Read more.

In this paper, we develop a tractable mathematical model and an emulation framework for communicating information through water using acoustic signals. Water is considered one of the most complex media to model due to its vastness and variety of characteristics, which depend on the scenario, the type of water body (lakes, rivers, tanks, sea, etc.), and the geographical location of the water body being considered. Our proposed mathematical model involves the concept of damped harmonic oscillators to represent the medium (water); Milne’s oscillator technique is used to map the interaction between the acoustic signal and water. Wave equations formulated for acoustic pressure and acoustic wave velocity are employed to characterise the travelling acoustic signal. The signal strength, phase shift, and time delay generated from the mathematical model are then inputted into a Simulink-based emulator framework to generate channel samples and channel impulse responses. The emulator utilises the wide sense stationary uncorrelated scattering (WSSUS) assumption and a finite sum-of-sinusoids (SOS) approach with a uniformly distributed phase to generate the channel samples. By utilising this emulator platform, it becomes feasible to generate profiles for amplitude variation, the Doppler shift, and spread experienced by any travelling signal in various underwater communication scenarios. Such a platform can be employed to simulate different communication scenarios, underwater network topologies, and data for training various learning models. Additionally, it can predict the performance of different modulation, multiplexing, error correction, and multi-access techniques for underwater acoustic communication (UWAC) systems. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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14 pages, 5325 KiB

Open AccessArticle

Simulation Analysis of the Motion of Superparamagnetic Particles in Liquid-Phase Fluid under a Magnetic Field

by Qiangqiang Zhang, Hui Song, Ruhong Song and Xianguo Hu

Appl. Sci. 2023, 13(9), 5406; https://doi.org/10.3390/app13095406 - 26 Apr 2023

Cited by 3 | Viewed by 1258

Abstract

Based on the magnetic response of magnetic particles, the targeting of particles to a target area under the modulation of an external magnetic field has been used in many applications. An accurate kinematic model is helpful to achieve accurate targeting of magnetic particles [...] Read more.

Based on the magnetic response of magnetic particles, the targeting of particles to a target area under the modulation of an external magnetic field has been used in many applications. An accurate kinematic model is helpful to achieve accurate targeting of magnetic particles and to investigate the factors influencing the motion of the particles. In the present paper, a segmental magnetization model was proposed based on the real magnetization process of superparamagnetic particles to calculate the magnetic force, and this was compared with a traditional magnetization model. The effects of magnetic field strength and particle diameter on the trajectory of magnetic particles in fluids under a magnetic field were further analyzed using a finite element analysis software. The simulation results show that changing the particle size only affected the velocity of the particles and did not affect the trajectory. When magnetic field strength changed, magnetic particles showed different trajectories. Notably, when the magnetic field force in the Y direction was too large, meaning the gravity could be neglected, the trajectory of the particles no longer changed when the magnetic field strength was varied. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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19 pages, 6576 KiB

Open AccessArticle

Fault Diagnosis of Wind Turbine Planetary Gear Based on a Digital Twin

by Yi Wang, Wenlei Sun, Liqiang Liu, Bingkai Wang, Shenghui Bao and Renben Jiang

Appl. Sci. 2023, 13(8), 4776; https://doi.org/10.3390/app13084776 - 10 Apr 2023

Cited by 13 | Viewed by 2955

Abstract

Aiming at the problems of the traditional planetary gear fault diagnosis method of wind turbines, such as the poor timeliness of data transmission, weak visualization effect of state monitoring, and untimely feedback of fault information, this paper proposes a planetary gear fault diagnosis [...] Read more.

Aiming at the problems of the traditional planetary gear fault diagnosis method of wind turbines, such as the poor timeliness of data transmission, weak visualization effect of state monitoring, and untimely feedback of fault information, this paper proposes a planetary gear fault diagnosis method for wind turbines based on a digital twin. The method was used to build the digital twin model of wind turbines and analyze the wind turbines’ operating state utilizing virtual and real data. Empirical mode decomposition (EMD) was used, and an atom search optimization–support vector machine (ASO-SVM) model was established for planetary gear fault diagnosis. The digital twin model diagnoses faults and constantly revises the model based on the diagnostic results. The digital twin fault diagnosis system was implemented in the Unity3D platform. The experimental results demonstrate the feasibility of the proposed early-warning system for the real-time diagnosis of planetary gear faults in wind turbines. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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16 pages, 4383 KiB

Open AccessArticle

Piecewise Hybrid System with Cross-Correlation Spectral Kurtosis for Fault Diagnosis in Rolling Bearing of Wind Power Generator

by Shan Wang, Zijian Qiao and Pingjuan Niu

Electronics 2023, 12(7), 1548; https://doi.org/10.3390/electronics12071548 - 25 Mar 2023

Cited by 2 | Viewed by 1390

Abstract

As the core equipment of wind turbines, rolling bearings affect the normal operation of wind power generators, resulting in huge economic losses and significant social impacts in the case of faults. Most faults are not easily found because of the small vibration response [...] Read more.

As the core equipment of wind turbines, rolling bearings affect the normal operation of wind power generators, resulting in huge economic losses and significant social impacts in the case of faults. Most faults are not easily found because of the small vibration response of these rolling bearings that operate in harsh conditions. To address the problem that the fault identifications of rolling bearings are disturbed by the strong noise in wind power generators, an adaptive nonlinear method based on a piecewise hybrid stochastic resonance system with a novel cross-correlation spectral kurtosis is proposed. Then, the vibration signals collected from the fault point of the outer and inner rings are used to clarify the outstanding capability of the proposed method when compared with the maximum cross-correlation-kurtosis-based unsaturated stochastic resonance method. Furthermore, the machine learning method based on the medium tree was adopted to further prove the excellent performance of the piecewise hybrid stochastic resonance system with a novel cross-correlation spectral kurtosis for realizing the efficient detection of rolling bearing faults in wind power generators, which has important innovation significance and practical engineering value for ensuring the safe and stable operation of wind turbines. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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23 pages, 1870 KiB

Open AccessArticle

Dynamic Equivalent Model Considering Multiple Induction Motors for System Frequency Response

by Zhen Tang, Guoxing Mu, Jie Pan, Zhiwei Xue, Hong Yang, Mingyang Mei, Zhihao Zhang and Peng Kou

Energies 2023, 16(7), 2987; https://doi.org/10.3390/en16072987 - 24 Mar 2023

Cited by 2 | Viewed by 1470

Abstract

Renewable energy sources have been characterized by a persistent and rapid proliferation, which has resulted in a notable reduction in grid inertia over an extended period. There is a widely held belief that the primary source of inertia within the grid stems from [...] Read more.

Renewable energy sources have been characterized by a persistent and rapid proliferation, which has resulted in a notable reduction in grid inertia over an extended period. There is a widely held belief that the primary source of inertia within the grid stems from generation-side conventional units. However, in power consumption, a significant number of induction motors are present, which can inherently offer rotational inertia by virtue of their kinetic energy. To investigate the influence of induction motors on grid inertia, in this paper, we propose two types of models, i.e., a detailed grid model and a dynamic equivalent model that considers multiple induction motors. Specifically, the detailed grid model with multiple induction motors is first established. However, the detailed model requires the specific parameters of induction motors, which are hard to acquire in large systems. Moreover, the accuracy of the model is unsatisfactory. To fill these gaps, the dynamic equivalent model (DEM) is further proposed to emulate the detailed model. Compared with the detailed model, the proposed dynamic equivalent model is structurally simple and does not require the specific parameters of induction motors. Therefore, it is possible to apply to large systems for investigating the influence of induction motors on grid frequency dynamics. A genetic algorithm is introduced in order to figure out the parameters of the proposed dynamic equivalent model from historical frequency data. The proposed detailed model and dynamic equivalent model are evaluated on the IEEE 9-bus system in MATLAB and SimPowerSystems toolbox. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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18 pages, 10076 KiB

Open AccessArticle

The Influence of the Magnetic Field Line Curvature on Wall Erosion near the Hall Thruster Exit Plane

by Lulu Quan, Yong Cao, Bin Tian and Keyu Gong

Appl. Sci. 2023, 13(6), 3547; https://doi.org/10.3390/app13063547 - 10 Mar 2023

Cited by 2 | Viewed by 1403

Abstract

One of the main factors that limit the lifetime of the Hall effect Thrusters (HETs) is the erosion of the acceleration channel caused by the flux of energetic ions. The magnetic field that is curved and convex towards the anode has been widely [...] Read more.

One of the main factors that limit the lifetime of the Hall effect Thrusters (HETs) is the erosion of the acceleration channel caused by the flux of energetic ions. The magnetic field that is curved and convex towards the anode has been widely used in HETs because of its role in reducing the divergence angle of the ion beam and the channel wall erosion. However, the mechanism of the influence of the magnetic field line curvature on the wall erosion is not clear. Therefore, in this paper, a 2D3V numerical model based on the immersed-finite-element and particle-in-cell (IFE-PIC) method is established to simulate the radial-azimuthal plane near the exit of the Hall thruster. The effect of the tilt angle of the magnetic field line on the wall sputtering erosion rate is analyzed. The results show that compared to the case with the electric field E perpendicular to the magnetic field B, the energy of the ions hitting the channel wall is smaller and the wall erosion is weaker when the magnetic field lines are convex to the anode. As the tilt angle of the magnetic field lines increases from 0° to 60°, the erosion rate is reduced by 90%. Conversely, when the magnetic field lines are convex to the exit plane of the channel, the wall erosion is much more serious compared to the case with the orthogonal electric field E and the magnetic field B. As the tilt angle of the magnetic field line changes from 0° to 60°, the erosion rate is enhanced by 171%. The results in this paper are instructive for the design and optimization of the magnetic field of the HETs. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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16 pages, 5346 KiB

Open AccessArticle

A Digital Twin-Based State Monitoring Method of Gear Test Bench

by Jubo Li, Songlin Wang, Jianjun Yang, Huijie Zhang and Hengbo Zhao

Appl. Sci. 2023, 13(5), 3291; https://doi.org/10.3390/app13053291 - 4 Mar 2023

Cited by 6 | Viewed by 2476

Abstract

The gear test bench is important equipment for analyzing gear performance, detecting gear quality, and providing basic data for gear design and machining. In order to monitor the running state of the gear test bench, predict its running performance both timely and effectively, [...] Read more.

The gear test bench is important equipment for analyzing gear performance, detecting gear quality, and providing basic data for gear design and machining. In order to monitor the running state of the gear test bench, predict its running performance both timely and effectively, and guarantee its stable operation, a digital twin-based state monitoring method of the gear test bench is proposed in this paper. The state monitoring system of the gear test bench based on the digital twin model is constructed to simulate its normal running state in real time. On this basis, through the acquisition of physical information of the gear test bench, the developing of the state monitoring system, and the simulation of the digital twin model, the real-time state monitoring of the normal operation gear test bench is realized. The test results of the closed power flow gear test bench show that the digital twin simulation results of the gear test bench are basically consistent with it. The proposed state monitoring system can map the normal running state of the gear test bench, so as to realize the running state monitoring of the gear test bench. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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14 pages, 3543 KiB

Open AccessArticle

Development of a Reference Device for the Calibration of Optical One-Shot Time-Interval Measurements

by Dalibor Kuhinek, Tomislav Bratko, Hrvoje Vukošić and Ivica Gavranić

Electronics 2023, 12(2), 439; https://doi.org/10.3390/electronics12020439 - 14 Jan 2023

Viewed by 1283

Abstract

This paper presents the development of a device that creates two or more light pulses with a precision time delay in a range from microseconds to several seconds and for the purpose of the calibration of velocity of detonation (VOD) measurement instruments. The [...] Read more.

This paper presents the development of a device that creates two or more light pulses with a precision time delay in a range from microseconds to several seconds and for the purpose of the calibration of velocity of detonation (VOD) measurement instruments. The device was assembled, programmed, and tested for functionality. Measurements were conducted using a reference counter. First, a precision OCXO (oven-controlled crystal oscillator) was used as a clock source. For verification of programmed subroutines, a counter oscillator output port was used as a source of clock signal for the microcontroller. This enabled the cancellation of possible oscillator errors. The signal had to be converted from an AC sine signal to a signal with positive values only using a clamper circuit. By the proposed solution, a calculable standard of time delay between two light pulses was achieved. According to the obtained results, this device can be used to calibrate field measurement devices for VOD measurements in explosives or some other use where the measurement device records the time interval between multiple light pulses. This enables more confidence in measurement results, faster recognition of instrument drift and increases the quality of measurement. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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19 pages, 3448 KiB

Open AccessTutorial

Stability Analysis of Equilibrium Point and Limit Cycle of Two-Dimensional Nonlinear Dynamical Systems—A Tutorial

by Bin Wei

Appl. Sci. 2023, 13(2), 1136; https://doi.org/10.3390/app13021136 - 14 Jan 2023

Cited by 2 | Viewed by 3056

Abstract

The equilibrium state of a dynamical system can be divided into the equilibrium point and limit cycle. In this paper, the stability analysis of the equilibrium point and limit cycle of dynamical systems are presented through different and all possible approaches, and those [...] Read more.

The equilibrium state of a dynamical system can be divided into the equilibrium point and limit cycle. In this paper, the stability analysis of the equilibrium point and limit cycle of dynamical systems are presented through different and all possible approaches, and those approaches are compared as well. In particular, the author presented the stability analysis of the equilibrium point through phase plane approach, Lyapunov–LaSalle energy-based approach, and linearization approach, respectively, for two-dimensional nonlinear system, while the stability analysis of the limit cycle is analyzed by using the LaSalle local invariant set theorem and Poincaré–Bendixson theorem, which is only valid in two-dimensional systems. Different case studies are used to demonstrate the stability analysis of equilibrium point and limit cycle. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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22 pages, 1660 KiB

Open AccessArticle

A Hybrid Multi-Criteria Approach to the Vendor Selection Problem for Sensor-Based Medical Devices

by Constanta Zoie Radulescu and Marius Radulescu

Sensors 2023, 23(2), 764; https://doi.org/10.3390/s23020764 - 9 Jan 2023

Cited by 5 | Viewed by 1808

Abstract

Sensors for health are a dynamic technology and sensor-based medical devices (SMD) are becoming an important part of health monitoring systems in healthcare centers and ambulatory care. The rapid growth in the number, diversity and costs of medical devices and Internet of Things [...] Read more.

Sensors for health are a dynamic technology and sensor-based medical devices (SMD) are becoming an important part of health monitoring systems in healthcare centers and ambulatory care. The rapid growth in the number, diversity and costs of medical devices and Internet of Things (IoT) healthcare platforms imposes a challenge for healthcare managers: making a rational choice of SMD vendor from a set of potential SMD vendors. The aim of this paper is to develop a hybrid approach that combines a performance evaluation model and a multi-objective model for the SMD vendor selection problem. For determining the criteria weights in the performance evaluation model, an original version of the best worst method (BWM) is applied, which we call the flexible best worst method (FBWM). The multi-objective model has two objective functions; one is to maximize the SMD performance and the other is to minimize the SMD cost. A case study for the application of the hybrid approach for SMD procurement in a healthcare center is analyzed. The hybrid approach can support healthcare decision makers in their SMD procurement decisions. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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14 pages, 2481 KiB

Open AccessArticle

TEZE: A System to Enhance Safety in Highway Tunnels as a New Smartphone-Based Emergency Call Paradigm

by Romeo Giuliano, Franco Mazzenga, Emilio Tenaglia, Francesco Vatalaro, Alessandro Vizzarri and Gherardo Zei

Electronics 2023, 12(2), 333; https://doi.org/10.3390/electronics12020333 - 9 Jan 2023

Cited by 2 | Viewed by 1898

Abstract

In the European Union, the eCall system has been mandatory since 31 March 2018. The system enabled a significant increase in safety on roads and highways, making help faster in the event of an accident. However, based on circuit-switched 2G/3G communications and an [...] Read more.

In the European Union, the eCall system has been mandatory since 31 March 2018. The system enabled a significant increase in safety on roads and highways, making help faster in the event of an accident. However, based on circuit-switched 2G/3G communications and an onboard device called IVS, it is generally unavailable on legacy vehicles. Some of its limitations tend to be remedied by the future NG eCall based on 4G/5G packet-switched communications. This paper discusses why the IVS may be an Achilles’ heel of any future IVS-based eCall and analyzes the advantages of a smartphone-based system. The TEZE system, starting to be implemented and installed in Italian highway tunnels, is one first general-purpose safety system, allowing highly reliable smartphone-based emergency calls. It is based on a dedicated low-cost ground infrastructure that allows monitoring of the availability of emergency call service through the mobile radio networks of the operators present inside a tunnel. The system complies with the ISO/IEC 30141:2018 reference standard. Identifying functional/non-functional requirements and their verification criteria provides an overall validation of the analyzed system. The TEZE system has been implemented and tested on the field. We report and comment on some experimental results. The paper also examines some key functionalities for vehicular services that can be implemented in an integrated system based on smartphones and heterogeneous networks. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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12 pages, 1041 KiB

Open AccessArticle

Adaptive Dendritic Cell-Negative Selection Method for Earthquake Prediction

by Wen Zhou, Wuyang Lan, Zhiwei Ye, Zhe Ming, Jingliang Chen and Qiyi He

Electronics 2023, 12(1), 9; https://doi.org/10.3390/electronics12010009 - 20 Dec 2022

Cited by 1 | Viewed by 1952

Abstract

Earthquake prediction (EQP) is an extremely difficult task, which has been overcome by adopting various technologies, with no further transformation so far. The negative selection algorithm (NSA) is an artificial intelligence method based on the biological immune system. It is widely used in [...] Read more.

Earthquake prediction (EQP) is an extremely difficult task, which has been overcome by adopting various technologies, with no further transformation so far. The negative selection algorithm (NSA) is an artificial intelligence method based on the biological immune system. It is widely used in anomaly detection due to its advantages of requiring little normal data to detect anomalies, including historical seismic-events-based EQP. However, NSA can suffer from the undesirable effect of data drift, resulting in outdated normal patterns learned from data. To tackle this problem, the data changes must be detected and processed, stimulating fast algorithmic adaptation strategies. This study proposes a dendritic cell algorithm (DCA)-based adaptive learning method for drift detection and negative selection algorithm (DC-NSA) that dynamically adapts to new input data. First, this study adopts the Gutenberg–Richter (GR) law and other earthquake distribution laws to preprocess input data. Then, the NSA is employed for EQP, and then, the dendritic cell algorithm (DCA) is employed to detect changes to trigger gradient descent strategies and update the self-set in NSA. Finally, the proposed approach is implemented to predict the earthquakes of MW > 5 in Sichuan and the surroundings during the next month. The experimental results demonstrate that our proposed DC-NSA is superior to the existing state-of-the-art EQP approaches. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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16 pages, 1052 KiB

Open AccessArticle

Flexible IoT Agriculture Systems for Irrigation Control Based on Software Services

by Eva Palomar-Cosín and Marisol García-Valls

Sensors 2022, 22(24), 9999; https://doi.org/10.3390/s22249999 - 19 Dec 2022

Cited by 4 | Viewed by 2758

Abstract

IoT technology applied to agriculture has produced a number of contributions in the recent years. Such solutions are, most of the time, fully tailored to a particular functional target and focus extensively on sensor-hardware development and customization. As a result, software-centered solutions for [...] Read more.

IoT technology applied to agriculture has produced a number of contributions in the recent years. Such solutions are, most of the time, fully tailored to a particular functional target and focus extensively on sensor-hardware development and customization. As a result, software-centered solutions for IoT system development are infrequent. This is not suitable, as the software is the bottleneck in modern computer systems, being the main source of performance loss, errors, and even cyber attacks. This paper takes a software-centric perspective to model and design IoT systems in a flexible manner. We contribute a software framework that supports the design of the IoT systems’ software based on software services in a client–server model with REST interactions; and it is exemplified on the domain of efficient irrigation in agriculture. We decompose the services’ design into the set of constituent functions and operations both at client and server sides. As a result, we provide a simple and novel view on the design of IoT systems in agriculture from a sofware perspective: we contribute simple design structure based on the identification of the front-end software services, their internal software functions and operations, and their interconnections as software services. We have implemented the software framework on an IoT irrigation use case that monitors the conditions of the field and processes the sampled data, detecting alarms when needed. We demonstrate that the temporal overhead of our solution is bounded and suitable for the target domain, reaching a response time of roughly 11 s for bursts of 3000 requests. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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21 pages, 8273 KiB

Open AccessFeature PaperArticle

Influence of the Main Geometrical Parameters on the Design and Performance of Mixed Inflow Turbines

by Mohammed Amine Chelabi, Sergey Dobrotvorskiy, Yevheniia Basova, Borys A. Aleksenko, Milan Edl, Jan Zdebor and José Machado

Appl. Sci. 2022, 12(23), 12165; https://doi.org/10.3390/app122312165 - 28 Nov 2022

Cited by 4 | Viewed by 1646

Abstract

The blade shape is of great interest to hybrid turbine designers, due to its significant and direct impact on turbine performance. The inlet and outlet diameters of the vane affect the size of the rotor, which is limited because of the small space [...] Read more.

The blade shape is of great interest to hybrid turbine designers, due to its significant and direct impact on turbine performance. The inlet and outlet diameters of the vane affect the size of the rotor, which is limited because of the small space available in internal combustion engines. The effect of the ratio of the average inlet diameter and the average exducer inlet diameter on the performance of a mixed inlet turbine will be the focus of this study, which consists of two cases included herein for the purpose of illustrating the means of improving rotor performances and controlling the flow mass rate. In the first case, we achieved this by changing the average diameter of the exducer inlet, while, in the second one, we achieved this by changing the average inlet diameter. Additionally, the angles of the inlet and outlet blades were recalculated to preserve the same blade profile and to eliminate the effect of curvilinearity. It was noted that the shape of the blade was very sensitive to changes in the ratio of the investigated diameters, and—in both cases—interesting results were obtained. First, an increase in output work and in total static isentropic efficiency by 2.16% and 2.15%, respectively, was generated, with a saving of 3.52% of the used mass flow and a lighter rotor compared to one that used to take up the same space by using fixed average inlet diameter blades. In the second case, there was an increase in the output work by 3.31%, and in the total static isentropic efficiency by 3.34%, but the rotor became heavier and required an increase in the mass flow used. Since inter-blade flows are very complex, three-dimensional and viscous—featuring various types of secondary and eddy flows—the CFX.15-CFD code was used in all models to solve the averaged Navier–Stokes equations. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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15 pages, 1869 KiB

Open AccessArticle

Efficient Weighted Ensemble Method for Predicting Peak-Period Postal Logistics Volume: A South Korean Case Study

by Eunhye Kim, Tsatsral Amarbayasgalan and Hoon Jung

Appl. Sci. 2022, 12(23), 11962; https://doi.org/10.3390/app122311962 - 23 Nov 2022

Viewed by 1644

Abstract

Demand prediction for postal delivery services is useful for managing logistic operations optimally. Particularly for holiday periods, namely the Lunar New Year and Korean Thanksgiving Day (Chuseok) in South Korea, the logistics service increases sharply compared with the usual period, which makes it [...] Read more.

Demand prediction for postal delivery services is useful for managing logistic operations optimally. Particularly for holiday periods, namely the Lunar New Year and Korean Thanksgiving Day (Chuseok) in South Korea, the logistics service increases sharply compared with the usual period, which makes it hard to provide reliable operation in mail centers. This study proposes a Multilayer Perceptron-based weighted ensemble method for predicting the accepted parcel volumes during special periods. The proposed method consists of two main phases: the first phase enriches the training dataset via synthetic samples using unsupervised learning; the second phase builds two Multilayer Perceptron models using internal and external factor-derived features for prediction. The final result is estimated by the weighted average predictions of these models. We conducted experiments on 25 Korean mail center datasets. The experimental study on the dataset provided by Korea Post shows better performance than other compared methods. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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21 pages, 5444 KiB

Open AccessArticle

Optimizable Control Barrier Functions to Improve Feasibility and Add Behavior Diversity while Ensuring Safety

by Shilei Li, Zhimin Yuan, Yun Chen, Fang Luo, Zhichao Yang, Qing Ye, Wei Fu and Yu Fu

Electronics 2022, 11(22), 3657; https://doi.org/10.3390/electronics11223657 - 9 Nov 2022

Cited by 3 | Viewed by 2120

Abstract

Ensuring safety while retaining maximum performance is a basic requirement for automatic cyber-physical systems, especially for safety-critical applications. A quadratic programming optimization framework called MPC-CBF has recently been presented, which directly unifies model predictive control (MPC) with control barrier functions (CBFs) over the [...] Read more.

Ensuring safety while retaining maximum performance is a basic requirement for automatic cyber-physical systems, especially for safety-critical applications. A quadratic programming optimization framework called MPC-CBF has recently been presented, which directly unifies model predictive control (MPC) with control barrier functions (CBFs) over the prediction time horizon. However, the conservative nature of CBFs can lead to feasibility problems in real applications. Based on the analysis of the role of the decay rate and the conservative accumulation phenomenon in standard CBF formulations, this paper proposes to directly optimize CBF constraints within the MPC framework. By regarding CBFs as a safety restriction level indicator and an optimizable constraint within the MPC framework, the trade-off between feasibility and safety can be adaptively optimized. The proposed Optimizable CBF (OCBF) model removes the hyper-parameters selection problem in standard CBFs and can adaptively adjust the safety restriction level and increase behavior diversity by adding the corresponding objects in the cost function in MPC. To eliminate the accumulation effects of actual values of the CBF constraints in previous time steps, this paper further proposes a General OCBF (GOCBF) formulation. Compared with existing formulations, the safety margin defined in our GOCBF has intuitive physical meanings and thus provides a more flexible and intuitive mechanism to compromise different objects in terms of ensuring safety while not undermining basic feasibility. Experimental results demonstrate that our algorithm provides a more flexible and intuitive mechanism to achieve this, thus improving feasibility and adding behavior diversity in the MPC-CBF framework. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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19 pages, 2299 KiB

Open AccessArticle

Design and Implementation of a Cloud PACS Architecture

by Jacek Kawa, Bartłomiej Pyciński, Michał Smoliński, Paweł Bożek, Marek Kwasecki, Bartosz Pietrzyk and Dariusz Szymański

Sensors 2022, 22(21), 8569; https://doi.org/10.3390/s22218569 - 7 Nov 2022

Cited by 5 | Viewed by 6744

Abstract

The limitations of the classic PACS (picture archiving and communication system), such as the backward-compatible DICOM network architecture and poor security and maintenance, are well-known. They are challenged by various existing solutions employing cloud-related patterns and services. However, a full-scale cloud-native PACS has [...] Read more.

The limitations of the classic PACS (picture archiving and communication system), such as the backward-compatible DICOM network architecture and poor security and maintenance, are well-known. They are challenged by various existing solutions employing cloud-related patterns and services. However, a full-scale cloud-native PACS has not yet been demonstrated. The paper introduces a vendor-neutral cloud PACS architecture. It is divided into two main components: a cloud platform and an access device. The cloud platform is responsible for nearline (long-term) image archive, data flow, and backend management. It operates in multi-tenant mode. The access device is responsible for the local DICOM (Digital Imaging and Communications in Medicine) interface and serves as a gateway to cloud services. The cloud PACS was first implemented in an Amazon Web Services environment. It employs a number of general-purpose services designed or adapted for a cloud environment, including Kafka, OpenSearch, and Memcached. Custom services, such as a central PACS node, queue manager, or flow worker, also developed as cloud microservices, bring DICOM support, external integration, and a management layer. The PACS was verified using image traffic from, among others, computed tomography (CT), magnetic resonance (MR), and computed radiography (CR) modalities. During the test, the system was reliably storing and accessing image data. In following tests, scaling behavior differences between the monolithic Dcm4chee server and the proposed solution are shown. The growing number of parallel connections did not influence the monolithic server’s overall throughput, whereas the performance of cloud PACS noticeably increased. In the final test, different retrieval patterns were evaluated to assess performance under different scenarios. The current production environment stores over 450 TB of image data and handles over 4000 DICOM nodes. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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23 pages, 9182 KiB

Open AccessReview

Roof Fall Hazard Monitoring and Evaluation—State-of-the-Art Review

by Krzysztof Fuławka, Lech Stolecki, Marcin Szumny, Witold Pytel, Izabela Jaśkiewicz-Proć, Michel Jakić, Michael Nöger and Philipp Hartlieb

Energies 2022, 15(21), 8312; https://doi.org/10.3390/en15218312 - 7 Nov 2022

Cited by 11 | Viewed by 3131

Abstract

A roof fall hazard is still one of the major threats in the underground mining industry. Each such type of event always brings great risk to miners and causes serious interruptions in the process of rock excavation. In general, the possibility of roof [...] Read more.

A roof fall hazard is still one of the major threats in the underground mining industry. Each such type of event always brings great risk to miners and causes serious interruptions in the process of rock excavation. In general, the possibility of roof fall hazard occurrence is directly related to the local geology, the presence of horizontal stresses as well as the type of excavation method and the efficacy of the utilized roof support. Due to the complexity of this process, it is important to continuously evaluate the roof fall risk, especially in long life-time places where a mining crew is often present. Within this article, a detailed review of the current methods of monitoring and evaluating roof fall risk was presented. Based on the extensive literature survey, different types of devices were described, and their advantages and disadvantages were pointed out. Furthermore, new trends in the area of roof fall risk monitoring were described and discussed. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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13 pages, 420 KiB

Open AccessArticle

Stability Analysis for Linear Systems with a Differentiable Time-Varying Delay via Auxiliary Equation-Based Method

by Zongming Yin, Xiefu Jiang, Ning Zhang and Weihua Zhang

Electronics 2022, 11(21), 3492; https://doi.org/10.3390/electronics11213492 - 27 Oct 2022

Cited by 3 | Viewed by 1327

Abstract

This paper concentrates on the stability problem for linear systems with a differentiable time-varying delay via an auxiliary equation-based method. By supposing that the second-order derivative of the system state is available, an auxiliary equation is obtained. On the basis of the system [...] Read more.

This paper concentrates on the stability problem for linear systems with a differentiable time-varying delay via an auxiliary equation-based method. By supposing that the second-order derivative of the system state is available, an auxiliary equation is obtained. On the basis of the system equation and the auxiliary equation, we define a suitable delay-product-type augmented Lyapunov-Krasovskii functional (LKF), under which more delay and system state information can be exploited. Based on the LKF, by utilizing some vital lemmas, adding zero terms, and the convex analysis method, we propose a new stability condition that is less conservative. Finally, to illustrate the merit of the obtained stability condition, two typical numerical examples are given. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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16 pages, 3904 KiB

Open AccessArticle

Modeling and Analysis of a Thermophotovoltaic Integrated Self-Powered Furnace

by Praveen Cheekatamarla, Stephen Kowalski, Ahmad Abu-Heiba, Timothy LaClair and Kyle Gluesenkamp

Energies 2022, 15(19), 7090; https://doi.org/10.3390/en15197090 - 27 Sep 2022

Viewed by 1769

Abstract

This work investigates the energy efficiency and carbon reduction potential of self-powered residential building heating equipment using a thermodynamic modeling approach. An integrated thermophotovoltaic power module and residential scale furnace system (40,000 Btu/h) were modeled and studied in detail to assess the influence [...] Read more.

This work investigates the energy efficiency and carbon reduction potential of self-powered residential building heating equipment using a thermodynamic modeling approach. An integrated thermophotovoltaic power module and residential scale furnace system (40,000 Btu/h) were modeled and studied in detail to assess the influence of different design configurations on primary energy efficiency. Operational characteristics such as total power generation, electrical efficiency, and heat recovery were examined in a self-powered system configuration. A sensitivity analysis was conducted to determine the influence of the electric grid’s carbon dioxide footprint (carbon intensity) and the cost of electricity on the environmental, as well as the economic, benefit associated with the self-powered configuration. Compared with a traditional furnace powered by an electric grid at a carbon intensity of 0.5 kg CO_2eq/kWh_EL, the self-powered furnace was shown to decrease the annual carbon dioxide emissions by approximately 550 kg (~75% reduction), while also saving more than USD 200 in utility expenses, annually. Additionally, the carbon emission reduction potential of blending different concentrations of hydrogen in natural gas fuel was also studied. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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12 pages, 798 KiB

Open AccessArticle

Implementation and Review of the Axisymmetric Equilibrium System of RFX-Mod2 within the MARTe2 Framework

by Nicolò Ferron, Claudio Finotti, Gabriele Manduchi, Giuseppe Marchiori, Paolo Bettini, Domenico Abate and Roberto Cavazzana

Electronics 2022, 11(17), 2751; https://doi.org/10.3390/electronics11172751 - 1 Sep 2022

Cited by 1 | Viewed by 1185

Abstract

A major refurbishment of the toroidal complex of the RFX-mod device is in progress and it will include the removal of the Inconel vacuum vessel and a modification of the stainless steel supporting structure to be made vacuum-tight. The axisymmetric equilibrium control in [...] Read more.

A major refurbishment of the toroidal complex of the RFX-mod device is in progress and it will include the removal of the Inconel vacuum vessel and a modification of the stainless steel supporting structure to be made vacuum-tight. The axisymmetric equilibrium control in RFX-mod was responsible for the control of the plasma current, horizontal and vertical position along with its stability and the plasma shape. The new implementation framework, both hardware and software, is described. The system has been fully reviewed and modified, if needed, for its prospective use in RFX-mod2. In order to run tests in an operation-like context, the updated system has also been implemented in the MARTe2 framework, to be deployed for the real-time applications of RFX-mod2. The results of the previous versions were reproduced and the cycle-time requirements were met. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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23 pages, 9008 KiB

Open AccessArticle

Autonomous Vehicle with Emergency Braking Algorithm Based on Multi-Sensor Fusion and Super Twisting Speed Controller

by Turki Alsuwian, Rana Basharat Saeed and Arslan Ahmed Amin

Appl. Sci. 2022, 12(17), 8458; https://doi.org/10.3390/app12178458 - 24 Aug 2022

Cited by 18 | Viewed by 10076

Abstract

The automobile revolution and growth in the number of cars produced several issues, and vehicle accidents remain one of the most serious road-related issues. Human mistakes and a failure to brake quickly are the main causes of accidents. There may be serious outcomes [...] Read more.

The automobile revolution and growth in the number of cars produced several issues, and vehicle accidents remain one of the most serious road-related issues. Human mistakes and a failure to brake quickly are the main causes of accidents. There may be serious outcomes to driving when distracted. To address the aforementioned issues, an autonomous emergency braking system (AEBS) was developed. To support such an AEBS, scalable, reliable, secure, fault-tolerant, and interoperable technologies are required. An advanced emergency braking system (EBS) with sensor fusion is proposed in this paper that can autonomously identify a probable forward collision and activate the vehicle braking system to brake the vehicle to avoid or mitigate a collision. Additionally, it provides a non-linear speed controller that facilitates the AEBS to apply the brakes in an emergency. Sensor fusion using lidar, radar, and vision sensors makes the AEBS more efficient and more reliable to detect vehicles or obstacles and decreases the chance of collision to a minimum level. A MATLAB/Simulink environment was used for simulation experiments and the results demonstrated the stable operation of the AEBS to avoid forward collisions in the event of an error in the measurement of any one sensor while any vehicle is detected. The presented work establishes that the EBS sensor fusion unit is a highly reliable solution for detecting the leading vehicle at the proper time and the AEBS controller can apply the brake in the situation of forwarding obstacle detection. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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16 pages, 2554 KiB

Open AccessArticle

Consensus Problem and Formation Control for Heterogeneous Multi-Agent Systems with Switching Topologies

by Chunping Wang, Jiaqi Wang, Ping Wu and Jinfeng Gao

Electronics 2022, 11(16), 2598; https://doi.org/10.3390/electronics11162598 - 19 Aug 2022

Cited by 6 | Viewed by 1668

Abstract

The cooperative control problem of discrete-time multi-agent systems (MASs) is discussed, and bounded uncertain time-delays and directed switching topologies are considered. By applying model transformations and matrix theory, an augmented system method is introduced to handle a heterogeneous time-delay MAS. Then, the consensus [...] Read more.

The cooperative control problem of discrete-time multi-agent systems (MASs) is discussed, and bounded uncertain time-delays and directed switching topologies are considered. By applying model transformations and matrix theory, an augmented system method is introduced to handle a heterogeneous time-delay MAS. Then, the consensus problem of the system is turned to the convergence issue of the product of innumerable row stochastic matrices. Sufficient conditions for asymptotic consensus of the system under directed switching topologies are obtained. Moreover, a novel consensus-based formation control strategy is designed to gain sufficient and necessary conditions for the formation control of a second-order differential robot system. Finally, the effectiveness of the obtained results is verified through simulations. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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15 pages, 3340 KiB

Open AccessArticle

A Modeling Method of Agents and SOA in Advanced Avionics System Based on AADL

by Pingyu Deng, Qing Zhou, Dong An, Shihai Wang and Kui Li

Appl. Sci. 2022, 12(16), 8157; https://doi.org/10.3390/app12168157 - 15 Aug 2022

Cited by 4 | Viewed by 1747

Abstract

The modeling method of agents and service-oriented architecture (SOA) in avionics systems describes agents and SOA in avionics systems with models. To our knowledge, however, the current modeling methods cannot describe the behavior of agents and SOA accurately and do not fit well [...] Read more.

The modeling method of agents and service-oriented architecture (SOA) in avionics systems describes agents and SOA in avionics systems with models. To our knowledge, however, the current modeling methods cannot describe the behavior of agents and SOA accurately and do not fit well with the existing avionics system models. This paper addresses the above problems by presenting a modeling method based on architecture analysis and design language (AADL). In this method, the working states of agents are described by the mode components, with the working process being triggered by the input of agents; and the services are described by the process component. The application of the software system is described by the system components that contain several process components. Moreover, different modes of the system are used to describe different applications, and the transitions of application are triggered by specific application requests. Software architecture of an avionics system is modeled by the proposed method. This case demonstrates that the proposed method can accurately describe how agents and SOA work in a new way and fit well with the existing avionics system models. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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7 pages, 2130 KiB

Open AccessArticle

Calculation of Three-dimensional Energy Product for Isotropic Nd₂Fe₁₄B Magnet

by Namkyu Kim, Hee-Sung Han, Chul-Jin Choi, Ki-Suk Lee and Jihoon Park

Appl. Sci. 2022, 12(15), 7887; https://doi.org/10.3390/app12157887 - 5 Aug 2022

Viewed by 1833

Abstract

A conventional energy product calculated by the product of the B-field and the H-field is not sufficient for representing the performance of a magnet because it considers the homogeneous and only the uniaxial magnetic properties of the magnet. The conventional energy [...] Read more.

A conventional energy product calculated by the product of the B-field and the H-field is not sufficient for representing the performance of a magnet because it considers the homogeneous and only the uniaxial magnetic properties of the magnet. The conventional energy product has been compared with another energy product obtained by integrating the scalar product of the B-field and the H-field of each cell composed of the three-dimensional components. We investigated a model system by micromagnetic simulation using finite differential method (FDM) and calculated the full hysteresis of the magnet. The model system of a Nd₂Fe₁₄B magnet composed of grains with a diameter of about 100 nm was assumed. In the case of the isotropic multi-grain magnet, the energy product calculated by the integration method was 28% larger than the energy product obtained by the conventional way, although a discrepancy between the distribution of the magnetizations and the demagnetizing fields at the reversal process resulted in the decrease of the energy product. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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16 pages, 22444 KiB

Open AccessArticle

3D Measurement Method for Saturated Highlight Characteristics on Surface of Fuel Nozzle

by Yeni Li, Liang Hou and Yun Chen

Sensors 2022, 22(15), 5661; https://doi.org/10.3390/s22155661 - 28 Jul 2022

Cited by 2 | Viewed by 1673

Abstract

Saturated highlights on metal surfaces reduce the detection accuracy of fuel nozzles. In this paper, we propose an image inpainting method with a saturated highlight based on the statistics of similar patches used in prior segmentation of the subregion. The sequence image acquisition [...] Read more.

Saturated highlights on metal surfaces reduce the detection accuracy of fuel nozzles. In this paper, we propose an image inpainting method with a saturated highlight based on the statistics of similar patches used in prior segmentation of the subregion. The sequence image acquisition is based on the shape from focus in the five-axis platform. By our method, the focus measure (FM) operator and the window size are evaluated using the sharpness evaluation curve and calculating time. We observe that the detection accuracy is improved when the highlight area is filled by the highlight-free area within the same segmentation region. There are fewer deviation points in the three-dimensional (3D) point cloud that are extracted from the sequence images. The inlet circle and the outlet circle of the fuel nozzle are both detected by the two-dimensional (2D) Hough Transform (HT) method. Our experiments show that the method yields better results in 3D detection of the key parameters of fuel nozzles with the saturated highlight characteristics. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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15 pages, 5423 KiB

Open AccessArticle

Research on Wire-to-Two Fin Configuration for Positive Atmospheric Plasma by Electrokinetic Blower

by Mar Cogollo de Cádiz, Pedro Martí Balsalobre and Andrés Díaz Lantada

Energies 2022, 15(15), 5443; https://doi.org/10.3390/en15155443 - 27 Jul 2022

Cited by 1 | Viewed by 1406

Abstract

Interest in the development of electro-fluid-dynamic devices (EFDs) based on corona discharge is growing due to their advantages and applicability across different industrial sectors. On the one hand, their performance as forced convection motors, in terms of weight, volume, and absence of noise [...] Read more.

Interest in the development of electro-fluid-dynamic devices (EFDs) based on corona discharge is growing due to their advantages and applicability across different industrial sectors. On the one hand, their performance as forced convection motors, in terms of weight, volume, and absence of noise and moving parts, make them competitive against traditional systems such as fans. On the other hand, the actions of the corona discharge, in terms of elimination of viruses and bacteria, are already known. This paper studies the characteristics of corona discharge in terms of air flow for a new proposed configuration and geometry of electrodes. A systematic study is performed through a parametric study of the distances, power consumption, and size of the corona electrode. The characteristic voltage–current (CVCCs) and flow–pressure curves obtained provide design rules to use the generated corona discharge and the device itself, as a silent air propeller, which may also sterilize the surrounding environment and surfaces. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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17 pages, 1143 KiB

Open AccessArticle

Improving Security of Web Servers in Critical IoT Systems through Self-Monitoring of Vulnerabilities

by Linxuan Song and Marisol García-Valls

Sensors 2022, 22(13), 5004; https://doi.org/10.3390/s22135004 - 2 Jul 2022

Cited by 6 | Viewed by 2962

Abstract

IoT (Internet of Things) systems are complex ones that may comprise large numbers of sensing and actuating devices; and servers that store data and further configure the operation of such devices. Usually, these systems involve real-time operation as they are closely bound to [...] Read more.

IoT (Internet of Things) systems are complex ones that may comprise large numbers of sensing and actuating devices; and servers that store data and further configure the operation of such devices. Usually, these systems involve real-time operation as they are closely bound to particular physical processes. This real-time operation is often threatened by the security solutions that are put in place to alleviate the ever growing attack surface in IoT. This paper focuses on critical IoT domains where less attention has been paid to the web security aspects. The main reason is that, up to quite recently, web technologies have been considered unreliable and had to be avoided by design in critical systems. In this work, we focus on the server side and on how attacks propagate from server to client as vulnerabilities and from client to unprotected servers; we describe the concerns and vulnerabilities introduced by the intensive usage of web interfaces in IoT from the server templating engines perspective. In this context, we propose an approach to perform self monitoring on the server side, propagating the self monitoring to the IoT system devices; the aim is to provide rapid detection of security vulnerabilities with a low overhead that is transparent to the server normal operation. This approach improves the control over the vulnerability detection. We show a set of experiments that validate the feasibility of our approach. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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16 pages, 2299 KiB

Open AccessArticle

State Estimation of Gas-Lifted Oil Well Using Nonlinear Filters

by Ojonugwa Adukwu, Darci Odloak, Amir Muhammed Saad and Fuad Kassab Junior

Sensors 2022, 22(13), 4875; https://doi.org/10.3390/s22134875 - 28 Jun 2022

Cited by 3 | Viewed by 1744

Abstract

The focus of this work is the extension of nonlinear state estimation methods to gas-lifted systems. The extended Kalman filter (EKF), unscented Kalman filter (UKF) and particle filter (PF) were used to estimate the nonlinear states. Brief descriptions of the filters were first [...] Read more.

The focus of this work is the extension of nonlinear state estimation methods to gas-lifted systems. The extended Kalman filter (EKF), unscented Kalman filter (UKF) and particle filter (PF) were used to estimate the nonlinear states. Brief descriptions of the filters were first presented starting from the linear Kalman filter. Hypothesis tests on the expectation of the residuals were performed to show how close to optimal the estimation methods are and it showed the UKF estimates to be slightly better than EKF while PF performs the worst. The PF has poor accuracy using residual visualisation, hypothesis test and the root mean squared error (RMSE) values of the residuals. The gas-lifted system exhibits casing heading instability where the states show oscillatory behaviour depending on the value of the input but the results here do not change in a known way for each filter as the input is changed from the non-oscillatory region to the oscillatory region. Therefore, for this noise distribution and model assumption, either the EKF or UKF can be used for nonlinear state estimation with UKF better preferred if computational cost is not considered when control solutions are used in gas-lifted system. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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13 pages, 2746 KiB

Open AccessArticle

Resource Allocation for TDD Cell-Free Massive MIMO Systems

by Xuanhong Lin, Fangmin Xu, Jingzhao Fu and Yue Wang

Electronics 2022, 11(12), 1914; https://doi.org/10.3390/electronics11121914 - 20 Jun 2022

Cited by 4 | Viewed by 2098

Abstract

In this paper, we investigate a joint resource allocation algorithm in a time-division duplex (TDD)-based cell-free massive MIMO (CFMM) system, which has great potential to improve spectrum efficiency and throughput. Because the throughput of the system is a bottleneck due to the sharing [...] Read more.

In this paper, we investigate a joint resource allocation algorithm in a time-division duplex (TDD)-based cell-free massive MIMO (CFMM) system, which has great potential to improve spectrum efficiency and throughput. Because the throughput of the system is a bottleneck due to the sharing of the pilot, we attempted to alleviate pilot contamination. We propose a pilot assignment approach called user-distance-ordering-based pilot assignment (UDOPA) based on the distance between users and the center, which can be calculated by the K-means method. Then, using an access point (AP) selection algorithm, only the APs having a major impact on the macro diversity gain of a user are selected as the serving APs. In contrast to the existing AP selection algorithms, users with the same pilot are not allowed to share the same serving AP in the proposed AP selection algorithm, which also significantly reduces the complexity of data processing. Finally, a modified max–min power control scheme with teaching–learning-based optimization (TLBO) is proposed to further improve the performance of the systems and guarantee the minimum user rate. Simulation results show that the proposed joint resource allocation scheme can effectively enhance CFMM systems’ performance. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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30 pages, 9373 KiB

Open AccessArticle

Design and Fabrication of an Isolated Two-Stage AC–DC Power Supply with a 99.50% PF and ZVS for High-Power Density Industrial Applications

by Ahmed H. Okilly and Jeihoon Baek

Electronics 2022, 11(12), 1898; https://doi.org/10.3390/electronics11121898 - 16 Jun 2022

Cited by 4 | Viewed by 3913

Abstract

Power quality in terms of power factor (PF), efficiency, and total harmonic distortions (THDs) is an important consideration in power supplies designed for 5G telecom servers. This paper presents a different magnetic parts design and manufacturing techniques of power supplies, design and selection [...] Read more.

Power quality in terms of power factor (PF), efficiency, and total harmonic distortions (THDs) is an important consideration in power supplies designed for 5G telecom servers. This paper presents a different magnetic parts design and manufacturing techniques of power supplies, design and selection criteria of switching elements as well as the optimal design of control loops based on small-signal stability modeling and an appropriate stability criterion. The designed telecom power supply consists of the power factor correction (PFC) stage to increase the input power factor and the isolated phase-shift pulse width modulation (PWM) zero-voltage switching (ZVS) DC–DC converter stage to regulate the supply voltage to the specified load value while maintaining a high conversion efficiency. A two-stage outdoor telecom power supply with a power rating of 2 kW was designed and fabricated on a printed circuit board (PCB). The distinct two-stage power components of the power supply were subjected to loss analysis. Furthermore, PSIM simulation and experiments were used to demonstrate the total harmonic distortions (THDs), voltage ripples, power efficiency, and PF performance of the supply current for the proposed power supply under various operating situations. This work produces an industrial high power density power supply with a high PF, low THD and high conversion efficiency which is suitable for telecom power server applications. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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12 pages, 6575 KiB

Open AccessArticle

Monitoring the Geometric Position of Transition Zones to Increase the Quality and Safety of Railway Lines

by Stanislav Hodas, Jana Izvoltova, Jakub Chromcak and Dasa Bacova

Appl. Sci. 2022, 12(12), 6038; https://doi.org/10.3390/app12126038 - 14 Jun 2022

Cited by 11 | Viewed by 2437

Abstract

Transition zones on railway lines are localities with gradual changes in the construction layers in the connections between a fixed track and ballasted track or between a wide track and various railway objects, e.g., tunnels, bridges, culverts, etc. The different type of construction [...] Read more.

Transition zones on railway lines are localities with gradual changes in the construction layers in the connections between a fixed track and ballasted track or between a wide track and various railway objects, e.g., tunnels, bridges, culverts, etc. The different type of construction of transition zones causes a shock wave when the train passes, which can cause undesired effects on the stability of its construction, durability, and passengers’ comfort. For this reason, railway opera-tors pay increased attention to the construction inspection of these transition sections. The research deals with the description of the transition zones, methods, and results of their monitoring in experimental sections of the railway corridors. Innovative aspects are the measurements made using precise geodetic instruments as well as continuous measurements with the KRAB trolley. The analyses of measurements in the experimental sections of the track show whether the stability of the geometric spatial position is ensured. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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15 pages, 4123 KiB

Open AccessArticle

An Adaptive Bi-Mutation-Based Differential Evolution Algorithm for Multi-Threshold Image Segmentation

by Yu Sun and Yingying Yang

Appl. Sci. 2022, 12(11), 5759; https://doi.org/10.3390/app12115759 - 6 Jun 2022

Cited by 11 | Viewed by 1982

Abstract

Aiming at solving the problems of large calculation, time-consuming, and low segmentation accuracy of multi-threshold image segmentation, an adaptive threshold value based differential evolution algorithm is proposed in this paper. Firstly, an opposite learning strategy is introduced into the initial population to improve [...] Read more.

Aiming at solving the problems of large calculation, time-consuming, and low segmentation accuracy of multi-threshold image segmentation, an adaptive threshold value based differential evolution algorithm is proposed in this paper. Firstly, an opposite learning strategy is introduced into the initial population to improve the quality of the initial population; secondly, a threshold-value-based mutation strategy is proposed to balance the exploration and development capabilities of the algorithm, and the number of successfully evolved individuals is considered as a threshold value to adaptively adjust the evolution of superior and inferior individuals. Experiments demonstrate that the proposed algorithm has better performance in enhancing accuracy and speeding up the convergence. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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20 pages, 9692 KiB

Open AccessArticle

Factor Design for the Oxide Etching Process to Reduce Edge Particle Contamination in Capacitively Coupled Plasma Etching Equipment

by Ching-Ming Ku and Stone Cheng

Appl. Sci. 2022, 12(11), 5684; https://doi.org/10.3390/app12115684 - 3 Jun 2022

Cited by 4 | Viewed by 9981

Abstract

During the oxide layer etching process, particles in capacitively coupled plasma etching equipment adhere to the wafer edge and cause defects that reduce the yield from semiconductor wafers. To reduce edge particle contamination in plasma etching equipment, we propose changes in the voltage [...] Read more.

During the oxide layer etching process, particles in capacitively coupled plasma etching equipment adhere to the wafer edge and cause defects that reduce the yield from semiconductor wafers. To reduce edge particle contamination in plasma etching equipment, we propose changes in the voltage and temperature of the electrostatic chuck, plasma discharge sequence, gas flow, and pressure parameters during the etching process. The proposed edge particle reduction method was developed by analyzing particle maps after wafer etching. Edge particle adherence in plasma etching equipment can be reduced by decreasing the voltage and temperature changes of the electrostatic chuck and generating a plasma sheath with a continuous discharge sequence of radio-frequency plasma. The gas pressure and flow rate also affect the number of wafer edge particles. Experimental results were used to optimize the equipment parameters to reduce edge particle contamination and improve edge wafer defects after dry etching. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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27 pages, 8115 KiB

Open AccessArticle

Diagnosing the Machine Set Rotor Using Its Relative Vibrations

by Piotr Jan Bielawski

Appl. Sci. 2022, 12(11), 5660; https://doi.org/10.3390/app12115660 - 2 Jun 2022

Viewed by 1658

Abstract

The efficiency and dependability of machine set depends on the quality of maintenance of functional units of the machine set rotor. Diagnosing the functional units of the machine set can significantly increase the effectiveness and efficiency of the maintenance of the machine set. [...] Read more.

The efficiency and dependability of machine set depends on the quality of maintenance of functional units of the machine set rotor. Diagnosing the functional units of the machine set can significantly increase the effectiveness and efficiency of the maintenance of the machine set. The purpose of the study was to substantiate the separation of the machine set rotor and demonstrate the possibility of diagnosing such a functional unit using non-contact measurements of its relative vibrations. The measure of the wear margin of the machine set rotor was analyzed, and the symptoms of this measure were examined. Finally, the configuration of the relative vibration sensors of the machine set rotor was investigated. Three models of the relationship between the wear margin measures and the measures of the machine set rotor symptoms were developed for the machine set rotor with a crankshaft supported in slide bearings. One new sensors head (shaft position sensors head) of the relative vibration of the machine set rotor was designed. In each machine set, the rotor of the machine set can be distinguished. The developed models of relationships and designed sensors head can be used as parts of the diagnostic system of the supported slide bearings rotor of the machine set with the crankshaft. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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14 pages, 426 KiB

Open AccessArticle

Quantitative Assessment and Grading of Hardware Trojan Threat Based on Rough Set Theory

by Daming Yang, Cheng Gao and Jiaoying Huang

Appl. Sci. 2022, 12(11), 5576; https://doi.org/10.3390/app12115576 - 31 May 2022

Cited by 1 | Viewed by 1272

Abstract

The globalization of integrated circuit (IC) design and fabrication has given rise to severe concerns with respect to modeling strategic interaction between malicious attackers and Hardware Trojan (HT) defenders using game theory. The quantitative assessment of attacker actions has made the game very [...] Read more.

The globalization of integrated circuit (IC) design and fabrication has given rise to severe concerns with respect to modeling strategic interaction between malicious attackers and Hardware Trojan (HT) defenders using game theory. The quantitative assessment of attacker actions has made the game very challenging. In this paper, a novel rough set theory framework is proposed to analyze HT threat. The problem is formulated as an attribute weight calculation and element assessment in an information system without decision attributes. The proposed method introduces information content in the rough set that allows calculation of the weight of both core attributes and non-core attributes. For quantitative assessment, the HT threat is characterized by the closeness coefficient. In order to allow HT defenders to use fast and effective countermeasures, a threat classification method based on the k-means algorithm is proposed, and the Best Workspace Prediction (BWP) index is used to determine the number of clusters. Statistical tests were performed on the benchmark circuits in Trust-hub in order to demonstrate the effectiveness of the proposed technique for assessing HT threat. Compared with k-means, equidistant division-based k-means, and k-means++, our method shows a significant improvement in both cluster accuracy and running time. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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11 pages, 2933 KiB

Open AccessArticle

Determination of Pressure Drop Correlation for Air Flow through Packed Bed of Sinter Particles in Terms of Euler Number

by Junsheng Feng, Liang Zhao, Haitao Wang, Zude Cheng, Yongfang Xia and Hui Dong

Energies 2022, 15(11), 4034; https://doi.org/10.3390/en15114034 - 31 May 2022

Cited by 2 | Viewed by 1601

Abstract

In order to clearly understand the air flow resistance characteristics in vertical tanks for sinter waste heat recovery in the steel industry, experimental research on the air flow pressure drop (FPD) performance in a sinter bed layer (BL) was conducted. Based on a [...] Read more.

In order to clearly understand the air flow resistance characteristics in vertical tanks for sinter waste heat recovery in the steel industry, experimental research on the air flow pressure drop (FPD) performance in a sinter bed layer (BL) was conducted. Based on a self-made experimental device, the measurement values of air FPD for different experimental conditions were determined firstly, and then the concept of Euler number (Eu) in heat exchangers was introduced into the study of air FPD in BL; the change rules of Eu under different particle diameters were analyzed. Finally, the air FPD correlation in sinter BL was obtained and described in the form of Eu, and the error analysis of obtained air FPD correlation was performed. The results show that, the air FPD increases as a second power relationship with the increase in air superficial velocity when the particle diameter is constant. The decrease amplitude of Eu gradually dwindles when increasing the Reynolds number (Re), and the decrease in the Eu shows a reciprocal relationship with the Re. As the bed geometry factor increases, the FPD coefficient, A, decreases as an exponential relationship, while the FPD coefficient, B, increases as a first power relationship. The obtained air FPD correlation in the form of Eu in the experiment is well compatible with the measurement values, and the mean deviation of obtained correlation is 4.67%, showing good originality. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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20 pages, 7015 KiB

Open AccessArticle

An Industrial Fault Diagnostic System Based on a Cubic Dynamic Uncertain Causality Graph

by Xusong Bu, Hao Nie, Zhan Zhang and Qin Zhang

Sensors 2022, 22(11), 4118; https://doi.org/10.3390/s22114118 - 28 May 2022

Cited by 7 | Viewed by 2086

Abstract

This study presents an industrial fault diagnosis system based on the cubic dynamic uncertain causality graph (cubic DUCG) used to model and diagnose industrial systems without sufficient data for model training. The system is developed based on cloud native technology. It contains two [...] Read more.

This study presents an industrial fault diagnosis system based on the cubic dynamic uncertain causality graph (cubic DUCG) used to model and diagnose industrial systems without sufficient data for model training. The system is developed based on cloud native technology. It contains two main parts, the diagnostic knowledge base and the inference method. The knowledge base was built by domain experts modularly based on professional knowledge. It represented the causality between events in the target industrial system in a visual and graphical form. During the inference, the cubic DUCG algorithm could dynamically generate the cubic causal graph according to the real-time data and perform the logic and probability calculations based on the generated cubic DUCG models, visually displaying the dynamic causal evolution of faults. To verify the system’s feasibility, we rebuild a fault-diagnosis model of the secondary circuit system of No. 1 at the Ningde nuclear power plant based on the new system. Twenty-four fault cases were used to test the diagnostic accuracy of the system, and all faults were correctly diagnosed. The results showed that it was feasible to use the cubic DUCG platform for fault diagnosis. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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24 pages, 4351 KiB

Open AccessArticle

Optimization Workflows for Linking Model-Based Systems Engineering (MBSE) and Multidisciplinary Analysis and Optimization (MDAO)

by Christian Habermehl, Gregor Höpfner, Jörg Berroth, Stephan Neumann and Georg Jacobs

Appl. Sci. 2022, 12(11), 5316; https://doi.org/10.3390/app12115316 - 24 May 2022

Cited by 13 | Viewed by 3525

Abstract

Developing modern products involves numerous domains (controlling, production, engineering, etc.) and disciplines (mechanics, electronics, software, etc.). The products have become increasingly complex while their time to market has decreased. These challenges can be overcome by Model-Based Systems Engineering (MBSE), where all development data [...] Read more.

Developing modern products involves numerous domains (controlling, production, engineering, etc.) and disciplines (mechanics, electronics, software, etc.). The products have become increasingly complex while their time to market has decreased. These challenges can be overcome by Model-Based Systems Engineering (MBSE), where all development data (requirements, architecture, etc.) is stored and linked in a system model. In an MBSE system model, product requirements at the system level can lead to numerous technical variants with conflicting objectives at the parameter level. To determine the best technical variants or tradeoffs, Multidisciplinary Analysis and Optimization (MDAO) is already being used today. Linking MBSE and MDAO allows for mutually beneficial synergies to be expected that have not yet been fully exploited. In this paper, a new approach to link MBSE and MDAO is proposed. The novelty compared to existing approaches is the reuse of existing MBSE system model data. Models developed during upstream design and test activities already linked to the MBSE system model were integrated into an MDAO problem. Benefits are reduced initial and reconfiguration efforts and the resolution of the MDAO black-box behavior. For the first time, the MDAO problem was modeled as a workflow using activity diagrams in the MBSE system model. For a given system architecture, this workflow finds the design variable values that allow for the best tradeoff of objectives. The structure and behavior of the workflow were formally described in the MBSE system model with SysML. The presented approach for linking MBSE and MDAO is demonstrated using an example of an electric coolant pump. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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15 pages, 13132 KiB

Open AccessArticle

Performance Analysis of Acceleration and Inertial Force of Electromagnetic Suspension Inertial Stabilizer

by Sumei Gao, Longxiang Xu and Chaowu Jin

Appl. Sci. 2022, 12(11), 5304; https://doi.org/10.3390/app12115304 - 24 May 2022

Viewed by 1472

Abstract

In this paper, the structural characteristics of electromagnetic suspension (EMS) inertial stabilizers are analyzed firstly, and then a mechanical analysis of a single mass block and double mass block is carried out. The relationship model between the inertial anti-rolling mass block and inertial [...] Read more.

In this paper, the structural characteristics of electromagnetic suspension (EMS) inertial stabilizers are analyzed firstly, and then a mechanical analysis of a single mass block and double mass block is carried out. The relationship model between the inertial anti-rolling mass block and inertial force transmitted to the ship is established. The inertial force is determined by the number of coil turns, coil current, mass block, mass of the ship, electromagnet current, rate of change of the electromagnet current, air gap between the electromagnet and inertial mass block, and rotational angular speed. Through theoretical analysis, it is found that the response speed of inertia force is directly related to the electromagnetic coil current, the voltage at both ends of the electromagnetic coil, the coil resistance and the air gap. It is concluded that the response speed of the inertia force can be controlled by controlling the coil current, adjusting the voltage at both ends of the coil and adjusting the air gap. The inductance of the electromagnetic coil will also increase the nonlinearity of the inertial anti-roll system. On the basis of theoretical analysis, a digital simulation of EMS inertial stabilizer is carried out by MATLAB and ANSYS MAXWELL2D. Finally, a single mass block system of EMS inertial stabilizer is designed and tested. During the test, a 1.5 V sinusoidal excitation voltage is added to the electromagnetic coil after the mass block is suspended stably, and the maximum acceleration values of the inertial anti-rolling mass block and hull are 10.29 m/s² and 1.27 m/s². Finally, the theoretical analysis results, digital simulation results and experimental results are analyzed, which verifies the correctness of the acceleration and inertia force performance analysis of the EMS inertial stabilizer. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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15 pages, 2907 KiB

Open AccessArticle

Measurement of Large-Sized-Pipe Diameter Based on Stereo Vision

by Pu Liu, Lieshan Zhang and Meibao Wang

Appl. Sci. 2022, 12(10), 5277; https://doi.org/10.3390/app12105277 - 23 May 2022

Cited by 5 | Viewed by 2745

Abstract

To address the lack of fast and high-precision in situ measurement of large-sized pipes in current industrial applications, a pipe-diameter-measurement method based on stereo vision is designed in this paper. By using multiple sets of binocular cameras to perform 3D reconstruction and integration [...] Read more.

To address the lack of fast and high-precision in situ measurement of large-sized pipes in current industrial applications, a pipe-diameter-measurement method based on stereo vision is designed in this paper. By using multiple sets of binocular cameras to perform 3D reconstruction and integration of multiple laser markers projected on measured cross sections of pipes, the pipe diameter can be estimated. In this method, a measurement algorithm is adopted to enable automatic matching of feature points through affine distance transformation, and an optimized point-cloud-registration algorithm with normal-vector constraints is used to ensure measurement robustness. To verify the feasibility of the method, an experimental system was built under laboratory conditions, and three types of pipes with outer diameters from 285 mm to 325 mm were measured. The experimental results show that the relative error is within ±0.570% and the maximum repeatability standard deviation is 0.551 mm. The experimental results basically meet industrial standards, and the proposed method therefore has good application prospects. Full article

(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)

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