Graphs are prevalent in numerous real-world applications. Previous methods directly model graph structures and achieve significant success. However, these methods encounter bottlenecks due to the inherent irregularity of graphs. An innovative solution is converting graphs into textual representations, thereby harnessing the powerful capabilities of Large Language Models (LLMs) to process and comprehend graphs. In this article, we present a comprehensive review of methodologies for applying LLMs to graphs, termed LLM4graph. The core of LLM4graph lies in transforming graphs into texts for LLMs to understand and analyze. Thus, we propose a novel taxonomy of LLM4graph methods from the view of the transformation. Specifically, existing methods can be divided into two paradigms: Graph2text and Graph2token, which transform graphs into texts or tokens as the input of LLMs, respectively. We point out four challenges during the transformation to systematically present existing methods from a problem-oriented perspective. For practical concerns, we provide a guideline for researchers on selecting appropriate models and LLMs for different graphs and hardware constraints. To empirically evaluate our taxonomy and different technical choices, we conduct experiments with representative methods in Graph2text and Graph2token. We also identify five future research directions for LLM4graph.

The state of energy (SoE) is a critical metric for battery management systems, complementing the state of charge (SoC) in providing comprehensive battery management insights. This paper addresses SoE estimation for lithium-ion batteries by designing a sliding mode observer that utilizes sliding mode control technology to enhance the robustness of the SoE estimation algorithm. Leveraging the correlation between SoC and SoE, this study develops a method to accurately estimate SoC and determine SoE. Additionally, we introduce a sliding mode observer based on the Super-twisting algorithm, which stabilizes the observer by carefully selecting parameters. The effectiveness of the proposed SoE estimation algorithm is validated using Dynamic Stress Test (DST) data, confirming its practical utility.

A revolution in advanced manufacturing has been driven by digital technology in the fourth industrial revolution, also known as Industry 4.0, and has resulted in a substantial increase in profits for the industry. In a new paradigm of Industry 5.0, advanced manufacturing will step further and be capable of offering customized products and a better user experience. A number of key enabling technologies are expected to play crucial roles in assisting Industry 5.0 in meeting higher demands of data acquisition and processing, communications, and collaborative robots in the advanced manufacturing process. The aim of this survey is to provide novel insights into advanced manufacturing in Industry 5.0 by summarizing the latest progress of key enabling technologies, such as artificial intelligence of things (AIoT), beyond 5G communications, and collaborative robotics. Finally, key directions for future research to enable this vision to become a reality, such as the industrial metaverse, are outlined.

Abstract Recommender systems have been widely used for implementing personalised content on many mobile online services to reduce computational overload and preserve wireless data for users. The underlying mechanisms used for building recommender systems analyse data collected from users to make recommendations. This poses concerns over the privacy of data from users as both service providers and the cloud will have access. Privacy-preserving recommender systems protect user information by incorporating various cryptographic mechanisms to prevent accessing the data. However, existing works are not practical due to the use of heavy cryptography. In this paper, we propose an efficient privacy-preserving recommender system that takes advantage of clustering to improve efficiency. Using a secure clustering mechanism, user data are assigned to multiple clusters before being fed into the recommendation. Our proposed protocols are privacy-preserving and do not leak information that could be used to identify a data subject. The experiments show that our system is efficient and accurate.

This paper proposes a novel terminal sliding mode control (TSMC) method for grid-connected voltage source inverters (VSIs) in balanced three-phase three-wire grids. First, the mathematical model of the VSI is built. Then a double-loop TSMC controllers are presented for the DC-link voltage and the grid current respectively. The TSMC approach ensures stable and efficient VSI operation, effectively handling uncertainties and disturbances, and incorporates an LCL filter to enhance harmonic performance and overall power quality. Theoretical analysis and simulation studies validate the effectiveness and superiority of the proposed TSMC method.

This paper presents a study on the control of the neutral point of DC/AC converters connected to an unbalanced 3-phase 4-wire grid. The mathematical models of the converters, including an LCL filter, and the neutral line circuit in both balanced and unbalanced 3-phase 4-wire grids are developed. An active balancing method is employed to maintain the DC bus voltage's zero DC offset voltage. A virtual control technique is implemented in the controller design. Furthermore, a sliding mode control strategy is proposed to regulate the neutral point of DC/AC converters. The efficacy of the proposed approach is demonstrated through simulation results.

Recommender systems have become ubiquitous in many application domains such as e-commerce and entertainment to recommend items that are interesting to the users. Collaborative Filtering is one of the most widely known techniques for implementing a recommender system, it models user–item interactions using data such as ratings to predict user preferences, which could potentially violate user privacy and expose sensitive data. Although there exist solutions for protecting user data in recommender systems, such as utilising cryptography, they are less practical due to computational overhead. In this paper, we propose RSUC, a privacy-preserving Recommender System based on User Classification. RSUC incorporates homomorphic encryption for better data confidentiality. To mitigate performance issues, RSUC classifies similar users in groups and computes the recommendation in a group while retaining privacy and accuracy. Furthermore, an optimised approach is applied to RSUC to further reduce communication and computational costs using data packing. Security analysis indicates that RSUC is secure under the semi-honest adversary model. Experimental results show that RSUC achieves 4× performance improvement over the standard approach and offers 54× better overall performance over the existing solution.

In recent years, the development and utilization of Lithium-ion batteries have further promoted the development of electric vehicle and related battery management systems. Estimating the battery state of charge (SoC) is essential for battery management systems. Most studies on SoC estimation have focused on model-based observer designing. The sliding mode control strategy is suitable for estimating the battery SoC due to its strong robustness, insensitivity to parameter perturbation and external disturbance, and high estimation accuracy. This paper aims to design a battery SoC estimator using the proposed fuzzy sliding mode control strategy. The fuzzy control logic is introduced to suppress chattering by regulating the switching gain in the sliding mode control law. Firstly, the second-order Thevenin equivalent circuit model of the battery is established. Then a fuzzy sliding mode observer is designed based on the equivalent circuit model to estimate the battery’s SoC. Finally, the designed observer is simulated and verified.

This article proposes a continuous adaptive integral-type sliding-mode control approach for a class of mechatronic systems by taking into consideration matched and unmatched uncertainties, and uncertainty in the control gain. Four different sliding-mode controllers are designed to enable: 1) the avoidance of the singularity by preventing differentiating the system states with fractional power; and 2) the attenuation of the chattering by utilizing full-order sliding manifolds. The control gain adaptation in the full-order sliding-mode controller is presented to avoid the overestimation of the gain. With the continuous control in place, the mechatronic systems have a fast response with high precision. The soften action from carefully designed controllers with the gain adaptation guarantees the trajectories of the mechatronic systems to move smoothly and prevents damage to the mechanical components of the systems. Both the simulation and experimental results demonstrate the effectiveness and feasibility of the proposed control approach.

Presented here is a functional implementation of Distributed Ledger Technology applied to the task of cataloguing CCTV video evidence. We describe and demonstrate a prototype camera that participates in blockchain creation in real time, and the system designed to manage and coordinate its distribution and use. This application is of specific interest to law enforcement agencies charged with the management of high volumes of CCTV evidence. We discuss applicability and scalability with reference to simulation results and real-world testing. The combination of blockchain technology with a novel digital watermarking application is demonstrated here providing immediate benefit against an existing real-world problem of trustworthy evidence protection in distributed network environments.

An online estimation algorithm of State-of-Charge (SoC) of Lithium-ion (Li-ion) batteries based on terminal sliding mode (TSM) observer technique is proposed. A first-order RC equivalent circuit model is utilized to describe the dynamical behaviors of Li-ion batteries. A sliding mode observer is developed to track the states of the Li-ion batteries and the control signal of the observer is used to estimate the SoC of a Li-ion battery accurately. The proposed observer is robust to internal parameter uncertainties of the battery model, and the environment changes. Compared with the traditional sliding mode observers, the proposed sliding mode observer has the continuous control signal, which can be used for the SoC estimation algorithm directly. The proposed method has been verified by the estimation results and the effectiveness has benn demonstrated.

Recently, the state estimation issue of a TCP/IP network has attracted much attention from different communities. In this paper, a terminal sliding-mode observer (TSMO) is proposed based on a fluid-flow model of a TCP/IP network to estimate traffic flow states. A novel control strategy is proposed to fasten the convergence of the estimation error for average congestion window (ACwnd). Furthermore, a continuous control strategy is directly used to estimates the flooding rate of additional traffic flow (ATF). The efficacy of the proposed TSMO is verified by a numerical simulation implementations via the networking simulator NS-2.

It is generally preferred for the non-inverting buck-boost converter to operate in buck mode when the input voltage is higher than the output voltage and in boost mode vice versa to improve the efficiency. However, the performance of the converter would be degraded under this operating scheme when the input voltage approaches to the output voltage due to the occurrence of the dead-zone. The four-mode control method is a potential solution to eliminate the dead-zone issue. This paper is to analyze the operating principle and the performance of the converter with four-mode control method. A prototype with 16.8V output voltage is tested in the laboratory. Analytical and experimental results show that the converter can obtain high efficiency, fast load and input voltage transient response in the entire input voltage range with the four-mode control method.

This paper proposes an energy storage unit integrated dual input PV system with distributed maximum power point tracking (MPPT). Through applying a symmetrical configuration, the proposed PV system has a single stage structure to implement voltage boosting and inversion, which contributes to the advantages such as compact size and high power conversion efficiency. The design of the control strategy is relative easy due to the inherently decoupled connection among all ports of the system. Moreover, the intermittent nature of the solar power can be handled well by the integrated energy storage unit. The configuration and operation principle of the proposed PV system is explained and the design of the control strategy is derived in this paper. MATLAB/SIMULINK simulation results are used to verify the performance of the proposed PV system and the accordingly designed control strategy.

This paper proposes a full-order terminal sliding-mode based energy saving control for the grid-connected converter of induction motor systems. DC-link voltage and currents controllers of the converter are designed respectively using the full-order terminal sliding manifold and the related control strategies. The chattering in the sliding-mode control is attenuated, and continuous control signals are obtained. The energy-saving operation of the induction motor systems is achieved because the regenerative energy of the induction motor is fed back to the power grid with unity power factor. The simulation results validate the proposed method.

This paper proposes a gain margin technique based continuous sliding-mode control method for position servo systems of induction motors. A systematic design method for position and current controllers is developed to implement the robust control of induction motors in the field orientation control system. In the proposed controllers design, the boundaries of disturbances and parameter perturbations in the control system can be determined in advance based on the upper-bounds of uncertainties in the induction motor model. The gain margin technique is utilized to regulate the gain of the switching control. The chattering phenomenon are attenuated by using a continuous sliding-mode control method, so continuous control signals can be generated and directly applied in servo systems of induction motors. The simulation results show that the proposed method can implement high-performance position control of induction motors with improvement of steady-state and dynamic performances, control precision and robustness.

The standard application of nonsingular terminal sliding mode (NTSM) control is strictly limited to n-order (n≥2) systems and suffers from chattering problem. This paper proposes a continuous NTSM control for extended first order systems to obtain the global finite-time convergence and free-chattering simultaneously. Firstly, utilizing the concept of relative degree, a power-fractional NTSM manifold is designed. Then, based on Lyapunov stability theorem, a switching control law is designed to act on the derivative of NTSM variable, so that the real control is smoothed by integral action. Meanwhile, since the integral term is incompatible with input saturation in real systems, anti-windup compensation should be made accordingly. Taking permanent magnet synchronous motor as an example, simulation results are presented to validate the proposed method.

This paper investigates the robust control of two-link flexible manipulator systems subject to parameter perturbations, and a hybrid control scheme consisting of a continuous nonsingular terminal sliding mode (NTSM) controller and an observer-based LQR controller is proposed. In order to solve the non-minimum phase problem of flexible manipulator, singular perturbation method is utilized to decompose the system into a slow and fast subsystem in two-time scale, and joint angles and corrected flexible modes are modeled as the slow and fast variables, respectively. For the slow subsystem, a novel continuous NTSM control based on the concept of relative degree is proposed for robustness, finite-time convergence and free-chattering. For the fast subsystem, a reduced-order observer is designed to estimate corrected flexible modes and then a LQR controller is proposed for its optimal stability. Simulation results are presented to validate the control scheme.

Touch-based fingerprint sensor has been used in the mobile device, which can easily be hacked by an individual "fake fingerprint". Fingerprint captured by mobile camera is an alternative for identity authentication to control the access to the mobile device. However, the touch-less fingerprint needs to be captured under strictly controlled environment because only front view finger image presents useful minutiae information. It is very difficult for a user to capture an exactly front view image in reality. A mobile fingerprinting scheme for identity authentication is proposed in this paper. Multiple view fingerprint images are captured by mobile camera. A method for selecting the best candidate as the front view image is developed. Experimental result shows the effectiveness of the proposed method.

An electromagnetic relay test system is designed based on the 32-bit floating-point Microcontrollers (MCU): TMS320F28335. In the test system, the relay characteristic parameters, such as the coil resistance, pull-in voltage, release voltage and time parameters, can be tested by sampling of the relay coil current, electric shock voltage and drive supply voltage. The tested results can be displayed on the LCD and transmitted to PC. The sampling frequency of the system is 10 M Hertz, which is higher than the other relay test system. The whole system is portable and has low power consumption. Finally, the experimental results verify that the required parameters of the relay can be tested accurately using the designed system.

With the widely application of mobile commerce (m-commerce), there is an urgent need to introduce identity authentication mechanism to mobile devices and make m-commerce secure to users. Since fingerprints can be viewed as an important characteristic of a natural person, fingerprint authentication (FA) can provide excellent access control for mobile phone users. Generally speaking, there exist two methods for applying of FA to mobile devices: one solution is trying to introduce an extra sensor to a mobile device, the other solution is trying to authenticate an image captured by a mobile device directly. However, the drawback of the first method is that devices with specific sensors are usually unavailable, the critical difficulty for the second solution comes from minutiae matching since different images would be obtained by a camera with different snap in different positions are different. Facing with these difficulties, this paper trying to provide a possible novel method which combines 3D reconstruction with minutiae matching: reconstruction of 3D minutiae from two 2D images first and then match the obtained image with the reconstructed 3D minutiae.

SUMMARY This paper investigates face authentication based access control solutions for camera‐equipped mobile devices. A new hierarchical correlation based face authentication (HCFA) scheme is proposed, which suits resource‐constrained mobile devices such as mobile phones and personal digital assistants. The idea of HCFA is conducting a partial correlation output peak analysis (analyze the relationship between each cross‐correlation output peak generated from selected sub‐regions of a face), in conjunction with conventional direct cross‐correlation methods. The experimental results on the public domain database demonstrate that the proposed scheme achieved better performance than that of the conventional direct correlation based schemes. Furthermore, HCFA was implemented on the Nokia S60 CLDC emulator using Java ME (previously J2ME) programming technology in order to test the applicability and implementability. The test results show that the proposed algorithm is implementable on mobile devices. It not only shortens processing time but also reduces resource demand significantly, compared with the direct correlation algorithms. Copyright © 2011 John Wiley & Sons, Ltd.

Abstract Electrocardiography (ECG) signal is popularly used for diagnosing cardiovascular diseases (CVDs). However, in recent times ECG is being used for identifying person. As ECG signals contain sensitive private health information along with details for person identification, it needs to be encrypted before transmission through public media. Moreover, this encryption must be applied with minimal delay for authenticating CVD patients, as time is critical for saving CVD affected patient's life. Within this paper, we propose the usage of multi‐scroll chaos to encrypt ECG packets. ECG packets are being encrypted by the mobile phones using the chaos key by patients' subscribed in tele‐cardiology applications. On the other hand, doctors and hospital attendants receive the encrypted ECG packets, which can be decrypted using the same chaos key. Using the techniques described in this paper, end‐to‐end security can be applied to wireless tele‐cardiology application, with minimal processing. Our experimentation with 12 ECG segments shows that with multi‐scroll chaos implementation, CVD patients remain completely unidentified, upholding patients' privacy and preventing spoof attacks. Most importantly, the proposed method is 18 times faster than permutation‐based ECG encoding, 25 times faster than wavelet‐based ECG annonymization techniques and 31 times faster than noise‐based ECG obfuscation techniques, establishing the proposed technique as the fastest ECG encryption system according to the literature. Copyright © 2010 John Wiley & Sons, Ltd.

Abstract With fast evolution of mobile devices and mobile network, the need of protecting user sensitive information locally and performing secure user authentication remotely become evermore increasing. Bio‐cryptography is emerging as a powerful solution which can combine the advantages of conventional cryptography and biometric security. In this paper, we present an efficient bio‐cryptographic security protocol designed for client/server authentication in current mobile computing environment, with a reasonable assumption that server is secure. In this protocol, fingerprint biometric is used in user verification, protected by a computationally efficient Public Key Infrastructure (PKI) scheme, Elliptic Curve Cryptography (ECC). The genuine fingerprint information is hidden in the feature vault which is the mixture of genuine and chaff features. Fingerprint features are not only used for biometric verification but also for cryptographic key generation. Our security analysis shows that the proposed protocol can provide a secure and trustworthy authentication of remote mobile users over insecure network. Experimental results on public domain database show an acceptable verification performance. We also tested the computational costs and efficiency of our protocol on the CLDC emulator using Java ME (previous J2ME) programming technology. The simulation results prove that the proposed protocol suits current mobile environment. Copyright © 2010 John Wiley & Sons, Ltd.

Generating reliable biometric passwords/PINs is a very challenging research topic in access security control. This paper provides a method for the generation of a reliable password/PIN from fingerprint images. A fictitious triangle whose sides are composed of lines connecting two minutiae points closest to the core of a fingerprint image is constructed. The maximal side, the minimal and medial angles, together with the minutiae type involved in the three sides of this triangle are used as the source of password/PIN generation. The noise-tolerant transform criteria convert a decimal value to one digit PIN is provided. Experiments based on public database are presented.