Biblio

Promising means of detecting small UAVs are FMCW radar systems. Small UAVs with an RCS value of the order of 10−3••• 10−1m2 are characterized by a low SNR (less than 10 dB). To ensure an acceptable probability of detection in the resolution element (more than 0.9), it becomes necessary to reduce the detection threshold. However, this leads to a significant increase in the probability of false alarms (more than 10−3) and is accompanied by the appearance of a large number of false plots. The work describes an algorithm for trajectory detecting of a small UAV based on a “l/n-d” criterion using Kalman filtering in a spherical coordinate system due to FMCW radar data. Statistical analysis of algorithms based on two types of criteria “3/5-2” and “5/9-2” is performed. It is shown that the algorithms allow to achieve the probability of target trajectory detection greater than 0.9 and low probability of false detection of the target trajectory less than 10−4 with the false alarm probability in the resolution element 10−3••• 10−2•

Mortality from lung cancer has ranked high among cancers for many years. Early detection of lung cancer is critical for disease prevention, cure, and mortality rate reduction. Many existing detection methods on lung nodules can achieve high sensitivity but meanwhile introduce an excessive number of false-positive proposals, which is clinically unpractical. In this paper, we propose the multi-head detection and spatial attention network, shortly MHSnet, to address this crucial false-positive issue. Specifically, we first introduce multi-head detectors and skip connections to capture multi-scale features so as to customize for the variety of nodules in sizes, shapes, and types. Then, inspired by how experienced clinicians screen CT images, we implemented a spatial attention module to enable the network to focus on different regions, which can successfully distinguish nodules from noisy tissues. Finally, we designed a lightweight but effective false-positive reduction module to cut down the number of false-positive proposals, without any constraints on the front network. Compared with the state-of-the-art models, our extensive experimental results show the superiority of this MHSnet not only in the average FROC but also in the false discovery rate (2.64% improvement for the average FROC, 6.39% decrease for the false discovery rate). The false-positive reduction module takes a further step to decrease the false discovery rate by 14.29%, indicating its very promising utility of reducing distracted proposals for the downstream tasks relied on detection results.

This paper studies adaptive control of bilateral teleoperation systems with false data injection attacks. The model of bilateral teleoperation system with false data injection attacks is presented. An off-line identification approach based on the least squares is used to detect whether false data injection attacks occur or not in the communication channel. Two Bernoulli distributed variables are introduced to describe the packet dropouts and false data injection attacks in the network. An adaptive controller is proposed to deal stability of the system with false data injection attacks. Some sufficient conditions are proposed to ensure the globally asymptotical stability of the system under false data injection attacks by using Lyapunov functional methods. A bilateral teleoperation system with two degrees of freedom is used to show the effectiveness of gained results.

To reduce the false negative rate in power data anomaly detection, enhance the overall detection accuracy and reliability, and create a more stable data detection environment, this paper designs a power big data anomaly detection method based on improved support vector machine technology. The abnormal features are extracted in advance, combined with the changes of power data, the multi-target anomaly detection nodes are laid, and on this basis, the improved support vector machine anomaly detection model is constructed. The anomaly detection is realized by combining the normalization processing of the equivalent vector. The final test results show that compared with the traditional clustering algorithm big data anomaly detection test group and the traditional multi-domain feature extraction big data anomaly detection test group, the final false negative rate of the improved support vector machine big data exception detection test group designed in this paper is only 2.04, which shows that the effect of the anomaly detection method is better. It is more accurate and reliable for testing in a complex power environment and has practical application value.

Frame detection is an important part of the reconnaissance satellite receiver to identify the terrestrial application specific messages (ASM) / VHF data exchange (VDE) signal, and has been challenged by Doppler shift and message collision. A constant false alarm rate (CFAR) frame detection strategy insensitive to Doppler shift has been proposed in this paper. Based on the double Barker sequence, a periodical sequence has been constructed, and differential operations have been adopted to eliminate the Doppler shift. Moreover, amplitude normalization is helpful for suppressing the interference introduced by message collision. Simulations prove that the proposed CFAR frame detection strategy is very attractive for the reconnaissance satellite to identify the terrestrial ASM/VDE signal.

Cyberattack on power system brings new challenges on the development of modern power system. Hackers may implement false data injection attack (FDIA) to cause unstable operating conditions of the power system. However, data from different power internet of things usually contains a lot of redundancy, making it difficult for current efficient discriminant model to precisely identify FDIA. To address this problem, we propose a deep learning network-based data fusion model to handle features from measurement data in power system. Proposed model includes a data enrichment module and a data fusion module. We firstly employ feature engineering technique to enrich features from power system operation in time dimension. Subsequently, a long short-term memory based autoencoder (LSTM-AE) is designed to efficiently avoid feature space explosion problem during data enriching process. Extensive experiments are performed on several classical attack detection models over the load data set from IEEE 14-bus system and simulation results demonstrate that fused data from proposed model shows higher detection accuracy with respect to the raw data.

With the continuous development of vehicular ad hoc networks (VANETs), it brings great traffic convenience. How-ever, it is still a difficult problem for malicious vehicles to spread false news. In order to ensure the reliability of the message, an effective trust management model must be established, so that malicious vehicles can be detected and false information can be identified in the vehicle ad hoc network in time. This paper presents a trust management model based on machine learning and active detection technology, which evaluates the trust of vehicles and events to ensure the credibility of communication. Through the active detection mechanism, vehicles can detect the indirect trust of their neighbors, which improves the filtering speed of malicious nodes. Bayesian classifier can judge whether a vehicle is a malicious node by the state information of the vehicle, and can limit the behavior of the malicious vehicle at the first time. The simulation results show that our scheme can obviously restrict malicious vehicles.

With the explosive growth of the internet of things (IoT) devices, there are amount of data requirements and computing tasks. Fog computing network that could provide computing, caching and communication resources closer to IoT devices (ID) is considered as a potential solution to deal with the vast computing tasks. To improve the performance of the fog computing network while ensuring data security, blockchain technology is enabled and a location-based reliable sharding (LRS) algorithm is proposed, which jointly considers the optimal number of shards, the geographical location of fog nodes (FNs), and the number of nodes in each shard. Firstly, the reliable sharding result is based on the reputation values of FNs, which are related to the decision information and historical reputation value of FNs in the consensus process. Moreover, a reputation based PBFT consensus algorithm is adopted to accelerate the consensus process. Furthermore, the normalized entropy is used to estimate the proportion of malicious nodes and optimize the number of shards. Finally, simulation results show the effectiveness of the proposed scheme.

Research on intelligent accounting system based on intelligent financial data sheet analysis system considering complex data mining is conducted in the paper. The expert audit system extracts business records from the business database according to the specified audit conditions, and the program automatically calculates the total amount of the amount data items, and then compares it with the standard or normal business, reflecting the necessary information such as differences and also possible audit trails. In order to find intrusion behaviors and traces, data collection is carried out from multiple points in the network system. The collection content includes system logs, network data packets, important files, and the status and the behavior of the user activities. Furthermore, complex data mining model is combined for the systematic analysis on the system performance. The simulation on the collected data is provided to the validate the performance.

The smooth operation of metering equipment is inseparable from the monitoring and analysis of equipment alarm events by automated metering systems. With the generation of big data in power metering and the increasing demand for information security of metering systems in the power industry, how to use big data and protect data security at the same time has become a hot research field. In this paper, we propose a hybrid expert model based on federated learning to deal with the problem of alarm information analysis and identification. The hybrid expert system can divide the metering warning problem into multiple sub-problems for processing, which greatly improves the recognition and prediction accuracy. The experimental results show that our model has high accuracy in judging and identifying equipment faults.

MCI patients can be benefited from cognitive training programs to improve their cognitive capabilities or delay the decline of cognition. This paper evaluated three types of commonly seen categories of cognitive training programs (non-computerized / traditional cognitive training (TCT), computerized cognitive training (CCT), and virtual/augmented reality cognitive training (VR/AR CT)) based on six aspects: stimulation strength, user-friendliness, expandability, customizability/personalization, convenience, and motivation/atmosphere. In addition, recent applications of each type of CT were offered. Finally, a conclusion in which no single CT outperformed the others was derived, and the most applicable scenario of each type of CT was also provided.

Under the background of rapid development of campus informatization, the information management of college students' innovative activities is slightly outdated, and the operation of the traditional innovative activity record system has gradually become rigid. In response to this situation, this paper proposes a B/S architecture-based information management system for college students' innovative activities based on the current situation that the network and computers are widely used, which is designed for the roles of relevant managers of students on campus, such as class teachers, teachers and counselors, and has developed various functions to meet the needs of such users as class teachers, including user The system is designed to meet the needs of classroom teachers, classroom teachers and tutors. In order to meet the requirements of generality, expandability and ease of development, the overall architecture of the system is based on the javaEE platform, with JSP technology as the main development technology.

Multi-active bridge (MAB) converter has played an important role in the power conversion of renewable-based smart grids, electrical vehicles, and more/all electrical aircraft. However, the increase of MAB submodules greatly complicates the control architecture. In this regard, the conventional centralized control strategies, which rely on a single controller to process all the information, will be limited by the computation burden. To overcome this issue, this paper proposes a decentralized power management strategy for MAB converter. The switching frequencies of MAB submodules are adaptively regulated based on the submodule local information. Through this effort, flexible electrical power routing can be realized without communications among submodules. The proposed methodology not only relieves the computation burden of MAB control system, but also improves its modularity, flexibility, and expandability. Finally, the experiment results of a three-module MAB converter are presented for verification.

Due to the intermittent nature of renewable energy sources, the implementation of energy storage systems (ESSs) is crucial for the reliable operation of microgrids. This paper proposes a peer-to-peer distributed secondary control scheme for accurate voltage restoration of distributed ESS units in a DC microgrid. The presented control framework only requires local and neighboring information to function. Besides, the ESSs communicate with each other through a sparse network in a discrete fashion compared to existing approaches based on continuous data exchange. This feature ensures reliability, expandability, and flexibility of the proposed strategy for a more practical realization of distributed control paradigm. A simulation case study is presented using MATLAB/Simulink to illustrate the performance and effectiveness of the proposed control strategy.

Having high safety and effective computational property, the elliptic curve cryptosystem is very suitable for embedded mobile environment with resource constraints. Power attack is a powerful cipher attack method, it uses leaking information of cipher-chip in its operation process to attack chip cryptographic algorithms. In view of the situation that the power attack on the elliptic curve cryptosystem mainly concentrates on scalar multiplication operation an improved algorithm FWNAF based on RWNAF is proposed. This algorithm utilizes the fragments window technology further improves the utilization ratio of the storage resource and reduces the “jitter phenomenon” in system computing performance caused by the sharp change in system resources.

Cryptocurrencies such as Bitcoin and Ethereum achieve decentralized payment by maintaining a globally distributed and append-only ledger. Recently, several researchers have sought to achieve privacy-preserving auditing, which is a crucial function for scenarios that require regulatory compliance, for decentralized payment systems. However, those proposed schemes usually cost much time for the cooperation between the auditor and the user due to leveraging complex cryptographic tools such as zero-knowledge proof. To tackle the problem, we present T-PPA, a privacy-preserving decentralized payment system, which provides customizable and efficient auditability by leveraging trusted execution environments (TEEs). T-PPA demands the auditor construct audit programs based on request and execute them in the TEE to protect the privacy of transactions. Then, identity-based encryption (IBE) is employed to construct the separation of power between the agency nodes and the auditor and to protect the privacy of transactions out of TEE. The experimental results show that T-PPA can achieve privacy-preserving audits with acceptable overhead.

The proliferation of real-time cyber-physical systems (CPS) is making profound changes to our daily life. Many real-time CPSs are security and safety-critical because of their continuous interactions with the physical world. While the general perception is that the security protection mechanism deployment is often absent in real-time embedded systems, there is no existing empirical study that measures the adoption of these mechanisms in the ecosystem. To bridge this gap, we conduct a measurement study for real-time embedded firmware from both a security perspective and a real-time perspective. To begin with, we collected more than 16 terabytes of embedded firmware and sampled 1,000 of them for the study. Then, we analyzed the adoption of security protection mechanisms and their potential impacts on the timeliness of real-time embedded systems. Besides, we measured the scheduling algorithms supported by real-time embedded systems since they are also security-critical.

Embedded systems involve an integration of a large number of intellectual property (IP) blocks to shorten chip's time to market, in which, many IPs are acquired from the untrusted third-party suppliers. However, existing IP trust verification techniques cannot provide an adequate security assurance that no hardware Trojan was implanted inside the untrusted IPs. Hardware Trojans in untrusted IPs may cause processor program execution failures by tampering instruction code and return address. Therefore, this paper presents a secure RISC-V embedded system by integrating a Security Monitoring Unit (SMU), in which, instruction integrity monitoring by the fine-grained program basic blocks and function return address monitoring by the shadow stack are implemented, respectively. The hardware-assisted SMU is tested and validated that while CPU executes a CoreMark program, the SMU does not incur significant performance overhead on providing instruction security monitoring. And the proposed RISC-V embedded system satisfies good balance between performance overhead and resource consumption.

With the development of embedded systems towards networking and intelligence, the security threats they face are becoming more difficult to prevent. Existing protection methods make it difficult to monitor jump instructions and their target addresses for tampering by attackers at the low hardware implementation overhead and performance overhead. In this paper, a hardware-assisted security monitoring module is designed to monitor the integrity of jump instructions and jump addresses when executing programs. The proposed method has been implemented on the Xilinx Kintex-7 FPGA platform. Experiments show that this method is able to effectively monitor tampering attacks on jump instructions as well as target addresses while the embedded system is executing programs.

To prevent all sorts of attacks, the technology of security service function chains (SFC) is proposed in recent years, it becomes an attractive research highlights. Dynamic orchestration algorithm can create SFC according to the resource usage of network security functions. The current research on creating SFC focuses on a single domain. However in reality the large and complex networks are divided into security domains according to different security levels and managed separately. Therefore, we propose a cross-security domain dynamic orchestration algorithm to create SFC for network security functions based on ant colony algorithm(ACO) and consider load balancing, shortest path and minimum delay as optimization objectives. We establish a network security architecture based on the proposed algorithm, which is suitable for the industrial vertical scenarios, solves the deployment problem of the dynamic orchestration algorithm. Simulation results verify that our algorithm achieves the goal of creating SFC across security domains and demonstrate its performance in creating service function chains to resolve abnormal traffic flows.

Cybersecurity for complex systems operating in cyber-physical environment is becoming more and more critical because of the increasing cyber threats and systems' vulnerabilities. Security by design is quite an important method to ensure the systems' normal operations and services supply. For the aim of coping with cyber-attack affections properly, this paper studies the resilient security control issue for time-varying delay systems in cyber-physical environment with state estimation and moving defense approach. Time-varying delay factor induced by communication and network transmission, or data acquisition and processing, or certain cyber-attacks, is considered. To settle the cyber-attacks from the perspective of system control, a dynamic system model considering attacks is presented, and the corresponding switched control model with time-varying delay against attacks is formulated. Then the state estimator for system states is designed to overcome the problem that certain states cannot be measured directly. Estimated states serve as the input of the resilient security controller. Sufficient conditions of the stability of the observer and control system are derived out with the Lyapunov stability analysis method jointly. A moving defense strategy based on anomaly detection and random switching is presented, in which an optimization problem for calculating the proper switching probability of each candidate actuator-controller pair is given. Simulation experimental results are shown to illustrate the effectiveness of the presented scheme.

In this paper, the distributed security control problem of connected vehicle systems (CVSs) is investigated under denial of service (DoS) attacks and uncertain dynamics. DoS attacks usually block communication channels, resulting in the vehicle inability to receive data from the neighbors. In severe cases, it will affect the control performance of CVSs and even cause vehicle collision and life threats. In order to keep the vehicle platoon stable when the DoS attacks happen, we introduce a random characteristic to describe the impact of the packet loss behavior caused by them. Dependent on the length of the lost packets, we propose a security platoon control protocol to deal with it. Furthermore, the security platoon control problem of CVSs is transformed into a stable problem of Markov jump systems (MJSs) with uncertain parameters. Next, the Lyapunov function method and linear matrix inequations (LMI) are used to analyze the internal stability and design controller. Finally, several simulation results are presented to illustrate the effectiveness of the proposed method.

With the development of the information age, the process of global networking continues to deepen, and the cyberspace security has become an important support for today’s social functions and social activities. Web applications which have many security risks are the most direct interactive way in the process of the Internet activities. That is why the web applications face a large number of network attacks. Interpretive dynamic programming languages are easy to lean and convenient to use, they are widely used in the development of cross-platform web systems. As well as benefit from these advantages, the web system based on those languages is hard to detect errors and maintain the complex system logic, increasing the risk of system vulnerability and cyber threats. The attack defense of systems based on interpretive dynamic programming languages is widely concerned by researchers. Since the advance of endogenous security technologies, there are breakthroughs on the research of web system security. Compared with traditional security defense technologies, these technologies protect the system with their uncertainty, randomness and dynamism. Based on several common network attacks, the traditional system security defense technology and endogenous security technology of web application based on interpretive dynamic languages are surveyed and compared in this paper. Furthermore, the possible research directions of those technologies are discussed.

Transient stability accidents induced by converter-based resources have been emerging frequently around the world. In this paper, the transient stability of the grid-tied voltage source converter (VSC) system is studied through estimating the basin of attraction (BOA) based on the hyperplane or hypersurface method. Meanwhile, fault critical clearing times are estimated, based on the approximated BOA and numerical fault trajectory. Further, the dynamic security region (DSR), an important index in traditional power systems, is extended to power-electronics-dominated power systems in this paper. The DSR of VSC is defined in the space composed of active current references. Based on the estimated BOA, the single-VSC-infinite-bus system is taken as an example and its DSR is evaluated. Finally, all these analytical results are well verified by several numerical simulations in MATLAB/Simulink.

Train operation is highly influenced by the rail track state and the surrounding environment. An abnormal obstacle on the rail track will pose a severe threat to the safe operation of urban rail transit. The existing general obstacle detection approaches do not consider the specific urban rail environment and requirements. In this paper, we propose an edge intelligence (EI)-based obstacle intrusion detection system to detect accurate obstacle intrusion in real-time. A two-stage lightweight deep learning model is designed to detect obstacle intrusion and obtain the distance from the train to the obstacle. Edge computing (EC) and 5G are used to conduct the detection model and improve the real-time detection performance. A multi-agent reinforcement learning-based offloading and service migration model is formulated to optimize the edge computing resource. Experimental results show that the two-stage intrusion detection model with the reinforcement learning (RL)-based edge resource optimization model can achieve higher detection accuracy and real-time performance compared to traditional methods.