The discrete, fractional order model of a two-dimensional temperature field using Grünwald-Letnikov

Bulletin of the Polish Academy of Sciences Technical Sciences

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Test artifacts, resembling real machine parts, allow quantitative evaluation of system performance and insight into individual errors, aiding in improvement and standardization in additive manufacturing.The article provides a comprehensive overview of existing test artifacts, categorized based on geometric features and material used.Various measurement techniques such as stylus profilometry and computed tomography are employed to assess these artifacts.It was shown that Selective Laser Melting (SLM) technology and titanium alloys are prevalent in artifact creation.Specific artifact categories include slits, angular aspects, length parameters, variable surfaces, and others, each accompanied by examples from research literature, highlighting diverse artifact designs and their intended applications.The paper critically discusses the main problems with existing geometries.It paper underscores the importance of user-friendly and unambiguous artifacts for dimensional control, particularly in surface metrology.It anticipates the continued growth of metrological verification in future manufacturing environments, emphasizing the need for precise and reliable measurement results to support decision-making in production conditions

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This study introduces a two-step reinforcement learning (RL) strategy tailored for "The Lord of the Rings: The Card Game", a complex multistage strategy card game. The research diverges from conventional RL methods by adopting a phased learning approach, beginning with a foundational learning step in a simplified version of the game and subsequently progressing to the complete, intricate game environment. This methodology notably enhances the AI agent’s adaptability and performance in the face of the unpredictable and challenging nature of the game. The paper also explores a multi-phase system where distinct RL agents are employed for various decision-making phases of the game. This approach has demonstrated remarkable improvement, with the RL agents achieving a winrate of 78.5 % at the highest difficulty level.

Konrad Godlewski

Bartosz Sawicki

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The quality parameters of surface layers synthesised using electrospark alloying (ESA) technology were analysed in this paper. The main focus was on the influence of equipment energy parameters on structure formation, specifically the effect of discharge energy and productivity. Microstructural analysis of the modified surface of C40 steel after nitriding by ESA using a paste containing nitrogen compounds injected into the interelectrode gap was conducted. The layer structure for all studied ESA parameters includes three areas: the upper "white layer", the diffusion zone below it and the substrate. The roughness of the surface is Ra ~ 0.9 μm at low discharge energy Wp = 0.13 J and Ra ~ 6 μm at Wp = 3.4 J. The microhardness, continuity, and surface roughness of the layers varied with Wp. The influence of ESA productivity on the structure was studied. The thickness of the hardened layer and the diffusion zone, as well as the microhardness and continuity, are affected by reduced productivity. For the same discharge energy, the thickness of the hardened layer increases by 10-18% with decrease in productivity compared to the classical mode. Studies have shown that a productivity loss has a positive effect on the quality characteristics of the coatings produced by the ESA process.

Oksana HAPONOVA

Viacheslav TARELNYK

Tomasz MOŚCICKI

Nataliia TARELNYK

150802

This article discusses an identification and modeling approach of a reluctance synchronous motor (RSM) based on the running rotor technique. The applied flux linkage approximation functions reflect the self-saturation and cross-saturation effects, and the applied mathematical model is continuous and differentiable. The proper design of the experiment is discussed, and relevant recommendations are made to ensure the mitigation of procedural mistakes in the experiments. A detailed analysis of the impact of configuration faults on the obtained experimental data is provided, considering distortions in the obtained flux linkage and inductance surfaces. Considering the achieved model accuracy, a novel model evaluation considering the achieved model accuracy technique based on transient current response is proposed.

Łukasz J. Niewiara

Michał Gierczyński

Tomasz Tarczewski

Lech M. Grzesiak

Dynamic modeling and identification of a reluctance synchronous machine parameters

In the present paper, we investigate the model of a single-server queueing system with unlimited queue (of MX /G/1/∞-type), random volume customers, unlimited memory buffer and multiple vacations. In analyzed system, arriving customers (that form Poisson entrance flow of groups of customers) transport some information measured in bytes so they are assumed to be additionally characterized by some non-negative random volume. Customer’s service time generally depends on his volume. Information delivered by a customer is written out into dedicated unlimited memory buffer until customer ends his service. In addition, in considered system the mechanism of multiple vacations is implemented which means that server can have some breaks (rests) for a random period of time but breaks begin only in the moments when there is no customer present in the system. The above-mentioned mechanism has obvious influence on customer’s waiting time and, in consequence, on customers’ total volume. For the introduced model, we obtain general formula for the steady-state customers’ total volume distribution in the terms of Laplace–Stieltjes transforms as well as formulae defining its first two moments. Analysis of some interesting, practical special cases of the model and numerical computations are attached as well together with examples of possible applications of the model regarding real telecommunication or computer systems.

Marcin Ziółkowski

O. Tikhonenko

150813

This review paper discusses the concept of a bidirectional Dual Active Bridge (DAB) DC/DC converter. Practical applications and control methods are explored, and various types of DAB converters are introduced and characterized. Aspects of operation are discussed, enriched by the results of theoretical analyses, simulations, and experimental measurements of the original authors works.

Serafin Bachman

Marek Turzyński

Marek Jasiński

150807

Vector controlled drives require stator current information for use in current feedback and/or state variable estimators. That is why the detection and compensation of possible CS damage is so important. This article focuses on current sensor (CS) fault-tolerant control (FTC) in induction motor (IM) drive systems. In contrast to solutions known from the literature, two Modified Luenberger Observers (MLO) were applied, allowing for high-quality estimation of currents used in the detector and fault compensator. In a simple implementation of a detection algorithm based on residuals, an adaptive threshold coefficient was employed, enabling effective detection of various types of faults, regardless of whether the second current sensor was faulty or intact. The presented solution was evaluated during both motor and regenerative operation, with faults occurring in transient states, unlike solutions known in the literature.

Michal Adamczyk

Teresa Orłowska-Kowalska

Current sensor fault-tolerant control based on modified Luenberger observers for safetycritical vector-controlled induction motor drives

This paper proposes a new Principal Component Analysis (PCA) scheme to perform fault detection and identification (FDI) for systems affected by process faults. In this scheme, a new modeling method which maximizes the model sensitivity to a certain process fault type is proposed. This method uses normal operating or known faulty data to build the PCA model and other faulty data to fix its structure. A new structuration method is proposed to identify the process fault. This method computes the common angles between the residual subspaces of the different modes. It generates a reduced set of detection indices that are sensitive to certain process fault and unsensitive to others. The proposed FDI scheme is successfully applied to the Tenessee Eastman Process (TEP) supposedly affected by several process faults.

Mohamed Guerfel

Anissa Ben Aicha

Kamel Belkhiria

Hassani Messaoud

150812

Forecasting future trajectories of intelligent agents presents a formidable challenge, necessitating the analysis of intricate scenarios and uncertainties arising from agent interactions. Consequently, it is judicious to contemplate the establishment of inter-agent relationships and the assimilation of contextual semantic information. In this manuscript, we introduce HTTNet, a comprehensive framework that spans three dimensions of information modeling: (1) the temporal dimension, where HTTNet employs a Time Encoder to articulate time sequences, comprehending the influences of past and future trajectories; (2) the social dimension, where the Trajectory Encoder facilitates the input of trajectories from multiple agents, thereby streamlining the modeling of interaction information among intelligent agents; (3) the contextual dimension, where the TF-Map Encoder integrates semantic scene input, amplifying HTTNet's cognitive grasp of scene information. Furthermore, HTTNet integrates a hybrid modeling paradigm featuring CNN and Transformer, transmuting map scenes into feature information for the Transformer. Qualitative and quantitative analyses on the nuScenes and interaction datasets highlight the exceptional performance of HTTNet, achieving 1.03 minADE10 and a 0.31 Miss Rate on nuScenes, underscoring its effectiveness in multi-agent trajectory prediction in complex scenarios.

Xianlei Ge

Xiaobo Sen

Xuanxin Zhou

Xiaoyan Li

150811

Low Density Parity Check (LDPC) is a channel coding technique widely utilized in the 5G New Radio standard, it is of utmost importance in facilitating proficient and secure communication in noisy environments by effectively minimizing errors during data transmission. It is primarily used in the 5G New Radio (NR) standard for encoding user information on the Physical Downlink Shared Channel (PDSCH). The necessity to satisfy the increasing expectations for throughput, latency, and dependability led to the decision to deploy LDPC codes for user data, especially in the enhanced mobile broadband (eMBB) and ultra-reliable and low-latency communications (URLLC) scenarios of 5G networks. The present system proposes the use of NRLDPC codes for the purpose of transmitting data across a lognormal multipath fading channel model in the presence of AWGN. Wireless communication channels often use a lognormal multipath fading channel model, where the received signal experiences both multipath fading and lognormal shadowing. The research investigates the effectiveness of NR-LDPC coding in improving QAM-OFDM system performance by analyzing two rate-compatible base graphs and comparing their effectiveness with an uncoded system. This analysis is crucial for optimizing communication network design, especially in scenarios where the integrity of data is of utmost importance. We introduce a new method to improve the 5G NR LDPC code capability under lognormal fading conditions. This approach develops a layered Min Sum (LMS) algorithm to provide enhanced error correcting capabilities. The developed and implemented decoding algorithm represents a significant advancement over traditional detection methods. The outcomes of the simulation provide evidence of the effectiveness of the proposed NR-LDPC coding techniques in terms of their error correction and identification capabilities. In addition, the developed LMS decoding algorithm has been shown to significantly decrease the BER of the system.

Mohammed Hussin Ali

Ghanim A. Al-Rubaye

150808

Stall flutter is a serious threat to the operational integrity in turbomachinery, particularly in the final stage rotors of steam turbines and in compressors. Although computer science has developed rapidly and much of the research can be carried out using numerical tools, the simulation of some phenomena, such as stall flutter, is still very challenging and needs to be supported by experimental data. This paper presents an innovative experimental linear blade cascade design with five prismatic blades with pitch degrees of freedom, designed to be operated in a low subsonic wind tunnel. The geometry of the blade cascade was chosen on the basis of the experimental and numerical tests to allow stall flutter initiation. New suspension, measurement and electromagnetic excitation systems were developed and experimentally tested to allow accurate measurement of aerodynamic damping during controlled flutter tests. The novelty of the experimental blade cascade is the possibility of single pulse excitation of the blades. The cascade can be brought to the edge of stability by adjusting the angle of attack and flow velocity, and then the pulse can be used to induce stall flutter. Measurement of both mechanical and flow characteristics, also demonstrated in this paper, will provide data for in-depth analysis of stall flutter initiation and propagation.

Pavel Šnábl

Chandra Shekhar Prasad

Pavel Procházka

Ludek Pešek

Václav Uruba

Vladislav Skála

150806

Components used for the structure of the GLObal Solar Wind Structure experiment in the NASA Interstellar Mapping and Acceleration Probe space mission, made of AA6061-T6 alloy, are subjected to the coating process, where the temperature affects its mechanical properties. The aim of this paper is to examine the impact of the coating thermal cycle on the mechanical properties of AA6061-T6 alloy, which is the load-carrying material in a spaceborne instrument. As a part of the manufacturing process, the parts made of AA6061-T6 are subjected to a coating process at a temperature of about 220°C for a time longer than 1h. This treatment modifies the mechanical properties of the alloy. To evaluate the consequences of this change for spaceborne components, mechanical testing and numerical simulation were carried out. It was found that as a result of the coating process, the reduction in AA6061-T6 yield strength is about 16%, which entails a decrease in the margins of safety by 25% at its maximum.

Tomasz Barciński

Robert Kosturek

Tomasz Kowalski

Maciej Bzowski

Roman Wawrzaszek

Karol Mostowy

Jędrzej Baran

Maciej Daukszo

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Zhaoming Chen

Jinsong Zou

Wei Wang

R Anusuya

Karthika Renuka

Ismail Akgül

Volkan Kaya

Erdal Karavas

Sonay Aydin

Ahmet Baran

Ahmed El

Baset Abd

El Halim

Ehab Hassan

Eid Bayoumi

Walid El-Khattam

Amr Ibrahim

Asraar Anjum

Meftah Hrairi

Abdul Aabid

Norfazrina Yatim

Maisarah Ali

Karolina Krzykowska-Piotrowska

Emilia Grabka

Ewa Dudek

Adam Rosiński

Kamil Maciuk

Aarohi Kumar Munshi

Ashish Patnaik

Sebastian Rzydzik

Piotr Kroczek

Marcin Łoś

Maciej Woźniak

Maciej Paszyński

Ewa Girejko

Agnieszka Malinowska

Dawid Kalandyk

Bogdan Kwiatkowski

Damian Mazur

Anita Białkowska

Patryk Suroń

Wojciech Kucharczyk

Barbora Hanulikova

Mohamed Bakar

Magdalena Gieleciak

Karol Janus

Łukasz Maj

Paweł Petrzak

Magdalena Bieda

Anna Electronics

Tetiana Manyk

Jan Sobieski

Kacper Matuszelański

Jarosław Rutkowski

Piotr Martyniuk

Piotr Pracki

Paulina Komorzycka

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The publication addresses the dynamic state challenges encountered during development of a Dual Active Bridge (DAB) converter within DC microgrid systems. The conventional startup method is identified as instigating a cascade of unfavorable outcomes, encompassing elevated starting current, transformer current asymmetry, DC voltage distortions, EMI and heightened thermal stress on semiconductor components. Additionally, it necessitates precise calibration of magnetic components and diodes. A proposed remedy to these issues is introduced, involving a control method based on an additional phase shift to modulate the current of the primary H bridge. This novel control methodology is posited as a means to mitigate the aforementioned undesirable effects associated with traditional converter initiation techniques. The research also delves into considerations of proper design procedure for the converter. Emphasis is placed on integrating the novel control methodology into the design framework to effectively address challenges arising during transient states. Validation of the proposed solution is substantiated through a series of laboratory tests, the results of which are comprehensively presented in the article. These tests affirm the efficiency of the system when incorporating the novel control methodology, thereby substantiating its practical utility in mitigating the identified issues during the initiation phase of the DAB converter in DC microgrid systems.

150328

In the paper a new, fractional order, discrete model of a two-dimensional temperature field is addressed. The proposed model uses Grünwald-Letnikov definition of the fractional operator. Such a model has not been proposed yet. Elementary properties of the model: practical stability, accuracy and convergence are analysed. Analytical conditions of stability and convergence are proposed and they allow to estimate the orders of the model. Theoretical considerations are validated using exprimental data obtained with the use of a thermal imaging camera. Results of analysis supported by experiments point that the proposed model assures good accuracy and convergence for low order and relatively short memory length.

Krzysztof Oprzędkiewicz

150332

In modern drive systems, the aim is to ensure their operational safety. Damage can occur not only to the components of the motor itself but also to the power electronic devices included in the frequency converter and the sensors in the measurement circuit. Critical damage to the electric drive that makes its further exploitation impossible can be prevented by using fault-tolerant control (FTC) algorithms. These algorithms are very often combined with diagnostic methods that assess the degree and type of damage. In this paper, a fault classification algorithm using an artificial neural network (ANN) is analysed for stator phase current sensors in AC motor drives. The authors confirm that the investigated classification algorithm works equally well on two different AC motors without the need for significant modifications, such as retraining the neural network when transferring the algorithm to another object. The method uses a stator current estimator to replace faulty sensor measurements in a vector control structure. The measured and estimated currents are then subjected to a classification process using a multilayer perceptron (MLP), which has the advantage of a small structure size compared to deep learning structures. The uniqueness of the method lies in the use of data in the training set that are not dependent on the parameters of a specific motor. Four types of current sensor faults were studied, namely total signal loss, gain error, offset, and signal saturation. Simulations were performed in a MATLAB/SIMULINK environment for drive systems with an induction motor (IM) and a permanent magnet synchronous motor (PMSM). The results show that the algorithm correctly evaluates the type of damage in more than 99.6% of cases regardless of the type of motor. Therefore, the results presented here may help to develop universal diagnostic methods that will work on a wide variety of motors.

Krystian Teler

Maciej Skowron

150336

The paper describes a novel, simple servo drive position controller, using only knowledge about the structure of the nonlinear model and the constraints met by individual components of the model. The desired behaviour of the position and velocity signals is obtained by imposing a time-varying constraint on the signal aggregating information about position and velocity tracking errors. The method allows you to determine the maximum control (servo drive current) necessary to achieve the control goal under the existing initial conditions and the selected reference trajectory. The control is constrained and consists in appropriate reaction when the trajectory approaches the barrier, the shape of which is responsible for the imposed properties of the transient and quasisteady state tracking error. In addition to the derivation of the control, a discussion of its possible variants and basic properties is presented. Control with time-varying constraints has been introduced, which allows the control objectives to be met with limited conservatism of the imposed constraints. The influence of technical factors related to actual speed and position measurements was discussed and the operation of the real drive on a laboratory stand was presented.

Marcin Jastrzębski

Jacek Kabziński

Przemysław Mosiołek

150335

自 1952 年 PAS 成立以来，《波兰科学院公报：技术科学》由波兰科学院第四部工程科学部出版双月刊。该期刊经过同行评审，并发表于印刷和电子表格。它是为发表来自多学科工程科学的原创高质量论文而设立的，优先考虑以下主题：人工智能和计算智能、生物医学工程和生物技术、土木工程、控制、信息学和机器人学、电子学、电信和光电子学、机械和航空工程、热力学、材料科学与纳米技术、电力系统和电力电子学。

Bulletin of the Polish Academy of Sciences: Technical Sciences

短名	Bull. Pol. Acad. Sci. Tech. Sci.
Journal Impact	1.27
国际分区	ENGINEERING, MULTIDISCIPLINARY(Q3)
期刊索引	SCI Q4中科院 4 区

ISSN	0239-7528, 2300-1917
h-index	49
国内分区	工程技术(4区)工程技术工程综合(4区)

涉及主题	计算机科学物理数学工程类量子力学材料科学人工智能热力学化学生物经济电气工程复合材料数学分析
出版信息	出版商: Polish Academy of Sciences，出版周期: Quarterly，期刊类型: journal
基本数据	创刊年份: 2004，原创研究文献占比: 97.32%，自引率:16.70%， Gold OA占比: 97.01%
平均审稿周期	网友分享经验：较慢,6-12周
平均录用比例	网友分享经验：容易