Applied sciences

Bulletin of the Polish Academy of Sciences Technical Sciences

Content

Bulletin of the Polish Academy of Sciences Technical Sciences | 2023 | 71 | 4

Download PDF Download RIS Download Bibtex

Abstract

The paper describes a novel online identification algorithm for a two-mass drive system. The multi-layer extended Kalman Filter (MKF) is proposed in the paper. The proposed estimator has two layers. In the first one, three single extended Kalman filters (EKF) are placed. In the second layer, based on the incoming signals from the first layer, the final states and parameters of the two-mass system are calculated. In the considered drive system, the stiffness coefficient of the elastic shaft and the time constant of the load machine is estimated. To improve the quality of estimated states, an additional system based on II types of fuzzy sets is proposed. The application of fuzzy MKF allows for a shorter identification time, as well as improves the accuracy of estimated parameters. The identified parameters of the two-mass system are used to calculate the coefficients of the implemented control structure. Theoretical considerations are supported by simulations and experimental tests.
Go to article

Authors and Affiliations

Kacper Śleszycki
1
ORCID: ORCID
Karol Wróbel
1
ORCID: ORCID
Krzysztof Szabat
1
ORCID: ORCID
Seiichiro Katsura
2
ORCID: ORCID

  1. Wrocław University of Science and Technology, Institute of Electrical Machines, Drives and Measurements, Wrocław, Poland
  2. Keio University, Department of System Design Engineering, Tokyo, Japan
Download PDF Download RIS Download Bibtex

Abstract

Illegal elements use the characteristics of an anonymous network hidden service mechanism to build a dark network and conduct various illegal activities, which brings a serious challenge to network security. The existing anonymous traffic classification methods suffer from cumbersome feature selection and difficult feature information extraction, resulting in low accuracy of classification. To solve this problem, a classification method based on three-dimensional Markov images and output self-attention convolutional neural network is proposed. This method first divides and cleans anonymous traffic data packets according to sessions, then converts the cleaned traffic data into three-dimensional Markov images according to the transition probability matrix of bytes, and finally inputs the images to the output self-attention convolution neural network to train the model and perform classification. The experimental results show that the classification accuracy and F1-score of the proposed method for Tor, I2P, Freenet, and ZeroNet can exceed 98.5%, and the average classification accuracy and F1-score for 8 kinds of user behaviors of each type of anonymous traffic can reach 93.7%. The proposed method significantly improves the classification effect of anonymous traffic compared with the existing methods.
Go to article

Authors and Affiliations

Xin Tang
1 2
Huanzhou Li
1 2
Jian Zhang
1 2
Zhangguo Tang
1 2
Han Wang
1 2
Cheng Cai
1 2

  1. School of Physics and Electronic Engineering, Sichuan Normal University, Chengdu 610101, Sichuan, China
  2. Institute of Network and Communication Technology, Sichuan Normal University, Chengdu 610101, Sichuan, China
Download PDF Download RIS Download Bibtex

Abstract

The individual identification of communication emitters is a process of identifying different emitters based on the radio frequency fingerprint features extracted from the received signals. Due to the inherent non-linearity of the emitter power amplifier, the fingerprints provide distinguishing features for emitter identification. In this study, approximate entropy is introduced into variational mode decomposition, whose features performed in each mode which is decomposed from the reconstructed signal are extracted while the local minimum removal method is used to filter out the noise mode to improve SNR. We proposed a semi-supervised dimensionality reduction method named exponential semi-supervised discriminant analysis in order to reduce the high-dimensional feature vectors of the signals, and LightGBM is applied to build a classifier for communication emitter identification. The experimental results show that the method performs better than the state-of-the-art individual communication emitter identification technology for the steady signal data set of radio stations with the same plant, batch and model.
Go to article

Authors and Affiliations

Wei Ge
1 2
ORCID: ORCID
Lin Qi
1 2
ORCID: ORCID
Lin Tong
1 2
Jun Zhu
1 2
Jing Zhang
1 2
Dongyang Zhao
3
Ke Li
1 2
ORCID: ORCID

  1. School of Information & Computer Science, Anhui Agricultural University, Hefei, Anhui, 230036, China
  2. Information Materials and Intelligent Sensing Laboratory of Anhui Province, Anhui University, Hefei, Anhui, 230601, China
  3. Shenzhen Institute for Advanced Study, University of Electronic Science and Technology of China, ShenZhen, GuangDong, 518000, China
Download PDF Download RIS Download Bibtex

Abstract

In the formulation, the existence, uniqueness and stability of solutions and parameter perturbation analysis to Riemann-Liouville fractional differential equations with integro-differential boundary conditions are discussed by the properties of Green’s function and cone theory. First, some theorems have been established from standard fixed point theorems in a proper Banach space to guarantee the existence and uniqueness of positive solution. Moreover, we discuss the Hyers-Ulam stability and parameter perturbation analysis, which examines the stability of solutions in the presence of small changes in the equation main parameters, that is, the derivative order η, the integral order β of the boundary condition, the boundary parameter ξ , and the boundary value τ. As an application, we present a concrete example to demonstrate the accuracy and usefulness of the proposed work. By using numerical simulation, we obtain the figure of unique solution and change trend figure of the unique solution with small disturbances to occur in different kinds of parameters.
Go to article

Authors and Affiliations

Nan Zhang
1
ORCID: ORCID
Lingling Zhang
2
ORCID: ORCID
Mercy Ngungu
3
Adejimi Adeniji
4
Emmanuel Addai
2

  1. College of Mathematics, Taiyuan University of Technology, 030024, TaiYuan, Shanxi, ChinaCollege of Mathematics, Taiyuan University of Technology, 030024, TaiYuan, Shanxi, China
  2. College of Mathematics, Taiyuan University of Technology, 030024, TaiYuan, Shanxi, China
  3. Human Sciences Research Council (HSRC), South Africa
  4. Tshwane university of Technology, South Africa
Download PDF Download RIS Download Bibtex

Abstract

Replacing mathematical models with artificial intelligence tools can play an important role in numerical models. This paper analyses the modeling of the hardening process in terms of temperature, phase transformations in the solid state and stresses in the elastic-plastic range. Currently, the use of artificial intelligence tools is increasing, both to make greater generalizations and to reduce possible errors in the numerical simulation process. It is possible to replace the mathematical model of phase transformations in the solid state with an artificial neural network (ANN). Such a substitution requires an ANN network that converts time series (temperature curves) into shares of phase transformations with a small training error. With an insufficient training level of the network, significant differences in stress values will occur due to the existing couplings. Long-Short-Term Memory (LSTM) networks were chosen for the analysis. The paper compares the differences in stress levels with two coupled models using a macroscopic model based on CCT diagram analysis and using the Johnson-Mehl-Avrami-Kolmogorov (JMAK) and Koistinen-Marburger (KM) equations, against the model memorized by the LSTM network. In addition, two levels of network training accuracy were also compared. Considering the results obtained from the model based on LSTM networks, it can be concluded that it is possible to effectively replace the classical model in modeling the phenomena of the heat treatment process.
Go to article

Authors and Affiliations

Joanna Wróbel
1
Adam Kulawik
1
ORCID: ORCID

  1. Department of Computer Science, Czestochowa University of Technology, Dabrowskiego 73, 42-201 Czestochowa, Poland
Download PDF Download RIS Download Bibtex

Abstract

In this paper we present an architecture for run-time reconfiguration of network-enabled ubiquitous devices. The whole idea is based on a policy-based system where the whole decision-making (e.g. anomaly detection-related) logic is provided in a form of an externally loaded policy file. The architecture is verified through real-life implementation on an embedded system whose sensitivity can be easily modified should a need arise in run-time without affecting network device/segment (and thus potentially a number of network services) so that they continue working while the re-configuration process is triggered.
Go to article

Authors and Affiliations

Mariusz Pelc
1 2
ORCID: ORCID
Dawid Galus
1
ORCID: ORCID
Mariusz Gola
1
ORCID: ORCID
Aleksandra Kawala-Sterniuk
1
ORCID: ORCID

  1. Faculty of Electrical Engineering, Automatic Control and Informatics, Opole University of Technology, Opole, Poland
  2. School of Computing and Mathematical Sciences, University of Greenwich, London, UK
Download PDF Download RIS Download Bibtex

Abstract

An axial flow tubular heat exchanger has been experimentally investigated to augment the heat transfer rate with a novel swirl flow of air past the heated tubes. The novel design has been based on circular baffle plates provided with trapezoidal air deflectors of various inclination angles. The arrangement of tubes is kept the same throughout the experiment, in accordance with the longitudinal airflow direction. The tubes maintained a constant heat flux condition over the surface. Four deflectors with equal inclination angles were developed on each baffle plate, generating air swirl inside a circular duct carrying the heated tubes that increase air-side turbulence and, consequently, the surface heat transfer rate. The baffle plates were placed equidistant from each other at variable pitch ratios. The Reynolds number was kept in the range of 16000– 2800