Biblio

In the field of airport passenger security, a new type of security inspection equipment called intelligent passenger security equipment is applied widely, which can significantly improve the efficiency of airport security screening and passenger satisfaction. This paper establishes a security check channel model based on intelligent passenger security check equipment, and studies the factors affecting the efficiency of airport security screening, such as the number of baggage unloading points, baggage loading points, secondary inspection points, etc. A simulation model of security check channel is established based on data from existing intelligent passenger security check equipment and data collected from Beijing Daxing Airport. Equipment utilization and queue length data is obtained by running the simulation model. According to the data, the bottleneck is that the manual inspection process takes too long, and the utilization rate of the baggage unloading point is too low. For the bottleneck link, an optimization scheme is proposed. With more manual check points and secondary inspection points and less baggage unloading points, the efficiency of airport security screening significantly increases by running simulation model. Based on the optimized model, the effect of baggage unloading point and baggage loading point on efficiency is further studied. The optimal parameter configuration scheme under the expected efficiency is obtained. This research can assist engineers to find appropriate equipment configuration quickly and instruct the airport to optimize the arrangement of security staff, which can effectively improve the efficiency of airport security screening and reduce the operating costs of airport.

Axie infinity is a complicated card game with a huge-scale action space. This makes it difficult to solve this challenge using generic Reinforcement Learning (RL) algorithms. We propose a hybrid RL framework to learn action representations and game strategies. To avoid evaluating every action in the large feasible action set, our method evaluates actions in a fixed-size set which is determined using action representations. We compare the performance of our method with two baseline methods in terms of their sample efficiency and the winning rates of the trained models. We empirically show that our method achieves an overall best winning rate and the best sample efficiency among the three methods.

In recent years, radar automatic target recognition (RATR) technology based on high-resolution range profile (HRRP) has received extensive attention in various fields. However, insufficient data on non-cooperative targets seriously affects recognition performance of this technique. For HRRP target recognition under few-shot condition, we proposed a novel gaussian deep belief network based on model-agnostic meta-learning (GDBN-MAML). In the proposed method, GDBN allowed real-value data to be transmitted over the entire network, which effectively avoided feature loss due to binarization requirements of conventional deep belief network (DBN) for data. In addition, we optimized the initial parameters of GDBN by multi-task learning based on MAML. In this way, the number of training samples required by the model for new recognition tasks could be reduced. We applied the proposed method to the HRRP recognition experiments of 3 types of 3D simulated aircraft models. The experimental results showed that the proposed method had higher recognition accuracy and generalization performance under few-shot condition compared with conventional deep learning methods.

The topological structure of the network relationship is described by the network diagram, and the formation and evolution process of the network is analyzed by using the cost-benefit method. Assuming that the self-interested network member nodes can connect or break the connection, the network topology model is established based on the dynamic random pairing evolution network model. The static structure of the network is studied. Respecting the psychological cognition law of college students and innovating the core value cultivation model can reverse the youth's identification dilemma with the core values, and then create a good political environment for the normal, healthy, civilized and orderly network participation of the youth. In recognition of the atmosphere, an automatic learning algorithm of Bayesian network structure that effectively integrates expert knowledge and data-driven methods is realized.

The FAA proposes Safety Continuum that recognizes the public expectation for safety outcomes vary with aviation sectors that have different missions, aircraft, and environments. The purpose is to align the rigor of oversight to the public expectations. An aircraft, its variants or derivatives may be used in operations with different expectations. The differences in mission might bring immutable risks for some applications that reuse or revise the original aircraft type design. The continuum enables a more agile design approval process for innovations in the context of a dynamic ecosystems, addressing the creation of variants for different sectors and needs. Since an aircraft type design can be reused in various operations under part 91 or 135 with different mission risks the assurance case will have many branches reflecting the variants and derivatives.This paper proposes a model for the holistic, performance-based, through-life safety assurance case that focuses applicant and oversight alike on achieving the safety outcomes. This paper describes the application of goal-based, technology-neutral features of performance-based assurance cases extending the philosophy of UL 4600, to the Safety Continuum. This paper specifically addresses component reuse including third-party vehicle modifications and changes to operational concept or eco-system. The performance-based assurance argument offers a way to combine the design approval more seamlessly with the oversight functions by focusing all aspects of the argument and practice together to manage the safety outcomes. The model provides the context to assure mitigated risk are consistent with an operation’s place on the safety continuum, while allowing the applicant to reuse parts of the assurance argument to innovate variants or derivatives. The focus on monitoring performance to constantly verify the safety argument complements compliance checking as a way to assure products are "fit-for-use". The paper explains how continued operational safety becomes a natural part of monitoring the assurance case for growing variety in a product line by accounting for the ecosystem changes. Such a model could be used with the Safety Continuum to promote applicant and operator accountability delivering the expected safety outcomes.

Despite the high directivity of THz beams, THz wireless links may still suffer compromising emissions when propagate through atmospheric turbulence and suffers scattering. In this work, we investigate the eavesdropping risks of a line-of-sight (LOS) THz link `in atmospheric turbulence with an eavesdropper located close to but outside of the beam path. A theoretical model considering the turbulence induced losses, gaseous absorption and beam divergence is conducted. Theoretical estimations agree well with our measured data. The secrecy capacity and outage probability dependent on the carrier frequency, turbulence strength, eavesdropper’s position and receiver sensitivity are analyzed.

The full integration of Remotely Piloted Aircraft Systems (RPAS) in non-segregated airspace is one of the major objectives for the worldwide aviation organizations and authorities. However, there are several technological and regulatory issues due to the increase of the air traffic in the next years and to the need of keeping high safety levels. In this framework, a real-time validation environment capable to simulate complex scenarios related to future air traffic management (ATM) conditions is of paramount importance. These facilities allow detailed testing and tuning of new technologies and procedures before executing flight tests. With such motivations, the Italian Aerospace Research Centre has developed the Integrated Simulation Facility (ISF) able to accurately reproduce ATM complex scenarios in real-time with hardware and human in-the-loop simulations, aiming to validate new ATM procedures and innovative system prototypes for RPAS and General Aviation aircraft. In the present work, the ISF facility has been used for reproducing relevant ATM scenarios to validate the functionalities of a Detect and Avoid system (DAA). The results of the ISF test campaign demonstrate the effectiveness of the developed algorithm in the autonomous resolution of mid-air collisions in presence of both air traffic and fixed obstacles (i.e. bad weather areas, no-fly-zone and terrain) and during critical flight phases, thus exceeding the current DAA state-of-the-art.

In this paper, we propose a method of stochastic model predictive control for energy management systems including human-in-the-loop. Here, we consider an air-conditioning system consisting of some rooms. Human decision making about the set temperature is modeled by a discrete-time Markov chain. The finite-time optimal control problem solved in the controller is reduced to a mixed integer linear programming problem.

Cyber-Physical System(CPS) is now a new evolutional morphology of embedded systems. With features of merging computation and physical processes together, the traditional verification and simulation methods have being challenged recently. After analyzed the state-of-art of related research, a new simulation environment is studied according to the characters of a special autonomous cyber-physical system-Unmanned Aerial Vehicle, and designed to be scene-driven, modeling and reconfigurable. In this environment, a novel CPS-in-loop architecture, which can support simulations under different customized scenes, is studied firstly to ensure its opening and flexibility. And as another foundation, some dynamics models of CPS and atmospheric ones of relative sensors are introduced to simulate the motion of CPS and the change of its posture. On the basis above, the reconfigurable scene-driven mechanisms that are Based on hybrid events are mainly excogitated. Then, different scenes can be configured in terms of special verification requirements, and then each scene will be decomposed into a spatio-temporal event sequence and scheduled by a scene executor. With this environment, not only the posture of CPS, but also the autonomy of its behavior can be verified and observed. It will be meaningful for the design of such autonomous CPS.

This paper presents ongoing work on the formalism of Cyber-Physical Systems (CPS) simulations. These systems are distributed real-time systems, and their simulations might be distributed or not. In this paper, we propose a model to describe the modular components forming a simulation of a CPS. The main goal is to introduce a model of generic simulation distributed architecture, on which we are able to execute a logical architecture of simulation. This architecture of simulation allows the expression of structural and behavioural constraints on the simulation, abstracting its execution. We will propose two implementations of the execution architecture based on generic architectures of distributed simulation: $\cdot$ The High Level Architecture (HLA), an IEEE standard for distributed simulation, and one of its open-source implementation of RunTime Infrastructure (RTI): CERTI. $\cdot$ The Distributed Simulation Scheduler (DSS), an Airbus framework scheduling predefined models. Finally, we present the initial results obtained applying our formalism to the open-source case study from the ROSACE case study.

From the beginning of technology and Wi-Fi based systems wireless networks had a prominent threat upon data security. Without security measures many organizations contribute on these flaws of security to make it better. There are many vulnerabilities of security models which are discussed in this article such as hacking through Wi-Fi security by Aircrack-ng, previous security model vulnerabilities and also the performance of Aircrack-ng attack on Wi-Fi modem or routers. In order to crack WPA/WPA2, kali Linux operating system will be needed along with Aircrack-ng packages installed on any compatible PC. Some of the new standard WPA3 such like downgrade problem on which the system will let the device to downgrade from WPA3 to WPA2 in order to connect with incompatible devise. Further, it makes a way for hackers to obtain Wi-Fi passwords even from new model defined such as WPA3 by using old techniques. The new model introduced Wi-Fi security protocol WPA3 is also no longer a secure model it can be penetrated. Researchers have discovered some new vulnerability enables hackers to get out the Wi-Fi passwords.

In this paper, we consider a wireless federated learning (FL) system concerning differential privacy (DP) guarantee, where multiple edge devices collaboratively train a shared model under the coordination of a central base station (BS) through over-the-air computation (AirComp). However, due to the heterogeneity of wireless links, it is difficult to achieve the optimal trade-off between model privacy and accuracy during the FL model aggregation. To address this issue, we propose to utilize the reconfigurable intelligent surface (RIS) technology to mitigate the communication bottleneck in FL by reconfiguring the wireless propagation environment. Specifically, we aim to minimize the model optimality gap while strictly meeting the DP and transmit power constraints. This is achieved by jointly optimizing the device transmit power, artificial noise, and phase shifts at RIS, followed by developing a two-step alternating minimization framework. Simulation results will demonstrate that the proposed RIS-assisted FL model achieves a better trade-off between accuracy and privacy than the benchmarks.

This paper presents a new micro linear actuator design. The North-South (NS) permanent magnet array configuration is assembled as the mobile part. The fixed part is designed to two-phase planar coils with no crossings avoiding interferences between overlapped conductors. The analytical calculation of the permanent magnet array verifies the feasibility of the finite element simulation. And then electromagnetic optimizations based on simulation to maximize the average thrust and minimize thrust ripple. In order to deal with millimeter level structure design, a microfabrication approach is adopted to process the new micro linear actuator in silicon material. The new micro linear actuator is able to perform millimeter level displacement strokes along a single axis in the horizontal plane. The experimental results demonstrate that the new micro linear actuator is capable of delivering variable strokes up to 5 mm with a precision error of 30 μm in position closed loop control and realizes the maximum velocity of 26.62mm/s with maximum error of 4.92%.

Waveguided air-coupled ultrasonic phased arrays offer grating-lobe-free beam forming for many applications such as obstacle detection, non-destructive testing, flow metering or tactile feedback. However, for industrial applications, the open output ports of the waveguide can be clogged due to dust, liquids or dirt leading to additional acoustic attenuation. In previous work, we presented the effectiveness of hydrophobic fabrics as a protection layer for acoustic waveguides. In this work, we created a numerical model of the waveguide including the hydrophobic fabric allowing the prediction of the insertion loss (IL). The numerical model uses the boundary element method (BEM) and the finite element method (FEM) in the frequency domain including the waveguide, the hydrophobic fabric and the finite-sized rigid baffle used in the measurements. All walls are assumed as ideal sound hard and the transducers are ideal piston transducers. The specific flow resistivity of the hydrophobic fabric, which is required for the simulation, is analyzed using a 3D-printed flow pipe. The simulations are validated with a calibrated microphone in an anechoic chamber. The IL of the simulations are within the uncertainties of the measurements. In addition, both the measurements and the simulations have no significant influence on the beamforming capabilities.

A non-predicted and transient malfunctioning of one or multiple unmanned aerial vehicles (UAVs) is something that may happen over a course of their deployment. Therefore, it is very important to have means to detect these events and take actions for ensuring a high level of reliability, security, and safety of the flight for the predefined mission. In this research, we propose algorithms aiming at the detection and isolation of any faulty UAV so that the performance of the UAVs application is kept at its highest level. To this end, we propose the use of Kullback-Leiler Divergence (KLD) and Artificial Neural Network (ANN) to build algorithms that detect and isolate any faulty UAV. The proposed methods are declined in these two directions: (1) we compute a difference between the internal and external data, use KLD to compute dissimilarities, and detect the UAV that transmits erroneous measurements. (2) Then, we identify the faulty UAV using an ANN model to classify the sensed data using the internal sensed data. The proposed approaches are validated using a real dataset, provided by the Air Lab Failure and Anomaly (ALFA) for UAV fault detection research, and show promising performance.

Semantic metadata is an important means to promote the integration of information and services and improve the level of search and discovery automation. Aiming at the problems that machine is difficult to handle service metadata description and lack of information metadata description in current SWIM information services, this paper analyzes the methods of metadata sematic empowerment and mainstream semantic metadata standards related to air traffic control system, constructs the SWIM information, and service sematic metadata model based on semantic expansion. The method of semantic metadata model mapping is given from two aspects of service and data, which can be used to improve the level of information sharing and intelligent processing.

In this study, we investigate the performance of FSO communication systems under more realistic channel model considering atmospheric turbulence, pointing errors and channel estimation errors together. For this aim, we first derived the composite probability density function (PDF) of imperfect Málaga turbulence channel with pointing errors. Then using this PDF, we obtained bit-error-rate (BER) and ergodic channel capacity (ECC) expressions in closed forms. Additionally, we present the BER and ECC metrics of imperfect Gamma-Gamma and K turbulence channels with pointing errors as special cases of Málaga channel. We further verified our analytic results through Monte-Carlo simulations.

In order to cope with the network attack of industrial control system, this paper proposes a quantifiable attack-defense tree model. In order to reduce the influence of subjective factors on weight calculation and the probability of attack events, the Fuzzy Analytic Hierarchy Process and the Attack-Defense Tree model are combined. First, the model provides a variety of security attributes for attack and defense leaf nodes. Secondly, combining the characteristics of leaf nodes, a fuzzy consistency matrix is constructed to calculate the security attribute weight of leaf nodes, and the probability of attack and defense leaf nodes. Then, the influence of defense node on attack behavior is analyzed. Finally, the network risk assessment of typical airport oil supply automatic control system has been undertaken as a case study using this attack-defense tree model. The result shows that this model can truly reflect the impact of defense measures on the attack behavior, and provide a reference for the network security scheme.

Hypergame theory has been used to model advantages in decision making. This research provides a formal representation of deception to further extend the hypergame model. In order to extend the model, we propose a hypergame theoretic framework based on temporal logic to model decision making under the potential for trust and deception. Using the temporal hypergame model, the concept of trust is defined within the constraints of the model. With a formal definition of trust in hypergame theory, the concepts of distrust, mistrust, misperception, and deception are then constructed. These formal definitions are then applied to an Attacker-Defender hypergame to show how the deception within the game can be formally modeled; the model is presented. This demonstrates how hypergame theory can be used to model trust, mistrust, misperception, and deception using a formal model.

Computer worms pose a major threat to computer and communication networks due to the rapid speed at which they propagate. Biologically based epidemic models have been widely used to analyze the propagation of worms in computer networks. For an air-gapped network with an insider threat, we propose a modified Susceptible-Exposed-Infected-Quarantined-Vaccinated (SEIQV) model called the Susceptible-Exposed-Infected-Quarantined-Patched (SEIQP) model. We describe the assumptions that apply to this model, define a set of differential equations that characterize the system dynamics, and solve for the basic reproduction number. We then simulate and analyze the parameters controlled by the insider threat to determine where resources should be allocated to attain different objectives and results.

In this paper we consider the threat surface and security of air gapped wallet schemes for permissioned blockchains as preparation for a Markov based mathematical model, and quantify the risk associated with private key leakage. We identify existing threats to the wallet scheme and existing work done to both attack and secure the scheme. We provide an overview the proposed model and outline justification for our methods. We follow with next steps in our remaining work and the overarching goals and motivation for our methods.

In this paper we consider the threat surface and security of air gapped wallet schemes for permissioned blockchains as preparation for a Markov based mathematical model, and quantify the risk associated with private key leakage. We identify existing threats to the wallet scheme and existing work done to both attack and secure the scheme. We provide an overview the proposed model and outline justification for our methods. We follow with next steps in our remaining work and the overarching goals and motivation for our methods.

Air-gap attacks and mimic defense are two emerging techniques in the field of network attack and defense, respectively. However, direct confrontation between them has not yet appeared in the real world. Who will be the winner, if air-gap attacks encounter mimic defense? To this end, a preliminary analysis is conducted for exploring the possible the strategy space of game according to the core principles of air-gap attacks and mimic defense. On this basis, an architecture model is proposed, which combines some detectors for air-gap attacks and mimic defense devices. First, a Dynamic Heterogeneous Redundancy (DHR) structure is employed to be on guard against malicious software of air-gap attacks. Second, some detectors for air-gap attacks are used to detect some signal sent by air-gap attackers' transmitter. Third, the proposed architecture model is obtained by organizing the DHR structure and the detectors for air-gap attacks with some logical relationship. The simulated experimental results preliminarily confirm the power of the new model.

Automotive systems are currently undergoing a rapid evolution through the integration of the Internet of Things (IoT) and Software Defined Networking (SDN) technologies. The main focus of this evolution is to improve the driving experience, including automated controls, intelligent navigation and safety systems. Moreover, the extremely rapid pace that such technologies are brought into the vehicles, necessitates the presence of adequate testing of new features to avoid operational errors. Apart from testing though, IoT and SDN technologies also widen the threat landscape of cyber-security risks due to the amount of connectivity interfaces that are nowadays exposed in vehicles. In this paper we present a new method, based on OMNET++, for testing new in-vehicle features and assessing security risks through network simulation. The method is demonstrated through a case-study on a Toyota Prius, whose network data are analyzed for the detection of anomalies caused from security threats or operational errors.

Securing Cyber-Physical Systems (CPS) against cyber-attacks is challenging due to the wide range of possible attacks - from stealthy ones that seek to manipulate/drop/delay control and measurement signals to malware that infects host machines that control the physical process. This has prompted the research community to address this problem through developing targeted methods that protect and check the run-time operation of the CPS. Since protecting signals and checking for errors result in performance penalties, they must be performed within the delay bounds dictated by the control loop. Due to the large number of potential checks that can be performed, coupled with various degrees of their effectiveness to detect a wide range of attacks, strategic assignment of these checks in the control loop is a critical endeavor. To that end, this paper presents a coherent runtime framework - which we coin BLOC - for orchestrating the CPS with check blocks to secure them against cyber attacks. BLOC capitalizes on game theoretical techniques to enable the defender to find an optimal randomized use of check blocks to secure the CPS while respecting the control-loop constraints. We develop a Stackelberg game model for stateless blocks and a Markov game model for stateful ones and derive optimal policies that minimize the worst-case damage from rational adversaries. We validate our models through extensive simulations as well as a real implementation for a HVAC system.