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2022-09-30
Burgetová, Ivana, Matoušek, Petr, Ryšavý, Ondřej.  2021.  Anomaly Detection of ICS Communication Using Statistical Models. 2021 17th International Conference on Network and Service Management (CNSM). :166–172.
Industrial Control System (ICS) transmits control and monitoring data between devices in an industrial environment that includes smart grids, water and gas distribution, or traffic control. Unlike traditional internet communication, ICS traffic is stable, periodical, and with regular communication patterns that can be described using statistical modeling. By observing selected features of ICS transmission, e.g., packet direction and inter-arrival times, we can create a statistical profile of the communication based on distribution of features learned from the normal ICS traffic. This paper demonstrates that using statistical modeling, we can detect various anomalies caused by irregular transmissions, device or link failures, and also cyber attacks like packet injection, scanning, or denial of service (DoS). The paper shows how a statistical model is automatically created from a training dataset. We present two types of statistical profiles: the master-oriented profile for one-to-many communication and the peer-to-peer profile that describes traffic between two ICS devices. The proposed approach is fast and easy to implement as a part of an intrusion detection system (IDS) or an anomaly detection (AD) module. The proof-of-concept is demonstrated on two industrial protocols: IEC 60870-5-104 (aka IEC 104) and IEC 61850 (Goose).
Baptiste, Millot, Julien, Francq, Franck, Sicard.  2021.  Systematic and Efficient Anomaly Detection Framework using Machine Learning on Public ICS Datasets. 2021 IEEE International Conference on Cyber Security and Resilience (CSR). :292–297.
Industrial Control Systems (ICSs) are used in several domains such as Transportation, Manufacturing, Defense and Power Generation and Distribution. ICSs deal with complex physical systems in order to achieve an industrial purpose with operational safety. Security has not been taken into account by design in these systems that makes them vulnerable to cyberattacks.In this paper, we rely on existing public ICS datasets as well as on the existing literature of Machine Learning (ML) applications for anomaly detection in ICSs in order to improve detection scores. To perform this purpose, we propose a systematic framework, relying on established ML algorithms and suitable data preprocessing methods, which allows us to quickly get efficient, and surprisingly, better results than the literature. Finally, some recommendations for future public ICS dataset generations end this paper, which would be fruitful for improving future attack detection models and then protect new ICSs designed in the next future.
2022-09-29
Suresh, V., Ramesh, M.K., Shadruddin, Sheikh, Paul, Tapobrata, Bhattacharya, Anirban, Ahmad, Abrar.  2021.  Design and Application of Converged Infrastructure through Virtualization Technology in Grid Operation Control Center in North Eastern Region of India. 2020 3rd International Conference on Energy, Power and Environment: Towards Clean Energy Technologies. :1–5.
Modern day grid operation requires multiple interlinked applications and many automated processes at control center for monitoring and operation of grid. Information technology integrated with operational technology plays a critical role in grid operation. Computing resource requirements of these software applications varies widely and includes high processing applications, high Input/Output (I/O) sensitive applications and applications with low resource requirements. Present day grid operation control center uses various applications for load despatch schedule management, various real-time analytics & optimization applications, post despatch analysis and reporting applications etc. These applications are integrated with Operational Technology (OT) like Data acquisition system / Energy management system (SCADA/EMS), Wide Area Measurement System (WAMS) etc. This paper discusses various design considerations and implementation of converged infrastructure through virtualization technology by consolidation of servers and storages using multi-cluster approach to meet high availability requirement of the applications and achieve desired objectives of grid control center of north eastern region in India. The process involves weighing benefits of different architecture solution, grouping of application hosts, making multiple clusters with reliability and security considerations, and designing suitable infrastructure to meet all end objectives. Reliability, enhanced resource utilization, economic factors, storage and physical node selection, integration issues with OT systems and optimization of cost are the prime design considerations. Modalities adopted to minimize downtime of critical systems for grid operation during migration from the existing infrastructure and integration with OT systems of North Eastern Regional Load Despatch Center are also elaborated in this paper.
Tang, Houjun, Xie, Bing, Byna, Suren, Carns, Philip, Koziol, Quincey, Kannan, Sudarsun, Lofstead, Jay, Oral, Sarp.  2021.  SCTuner: An Autotuner Addressing Dynamic I/O Needs on Supercomputer I/O Subsystems. 2021 IEEE/ACM Sixth International Parallel Data Systems Workshop (PDSW). :29–34.
In high-performance computing (HPC), scientific applications often manage a massive amount of data using I/O libraries. These libraries provide convenient data model abstractions, help ensure data portability, and, most important, empower end users to improve I/O performance by tuning configurations across multiple layers of the HPC I/O stack. We propose SCTuner, an autotuner integrated within the I/O library itself to dynamically tune both the I/O library and the underlying I/O stack at application runtime. To this end, we introduce a statistical benchmarking method to profile the behaviors of individual supercomputer I/O subsystems with varied configurations across I/O layers. We use the benchmarking results as the built-in knowledge in SCTuner, implement an I/O pattern extractor, and plan to implement an online performance tuner as the SCTuner runtime. We conducted a benchmarking analysis on the Summit supercomputer and its GPFS file system Alpine. The preliminary results show that our method can effectively extract the consistent I/O behaviors of the target system under production load, building the base for I/O autotuning at application runtime.
Casini, Daniel, Biondi, Alessandro, Cicero, Giorgiomaria, Buttazzo, Giorgio.  2021.  Latency Analysis of I/O Virtualization Techniques in Hypervisor-Based Real-Time Systems. 2021 IEEE 27th Real-Time and Embedded Technology and Applications Symposium (RTAS). :306–319.
Nowadays, hypervisors are the standard solution to integrate different domains into a shared hardware platform, while providing safety, security, and predictability. To this end, a hypervisor virtualizes the physical platform and orchestrates the access to each component. When the system needs to comply with certification requirements for safety-critical systems, virtualization latencies need to be analytically bounded for providing off-line guarantees. This paper presents a detailed modeling of three I/O virtualization techniques, providing analytical bounds for each of them under different metrics. Experimental results compare the bounds for a case study and quantify the contribution due to different sources of delay.
2022-09-20
Bentahar, Atef, Meraoumia, Abdallah, Bendjenna, Hakim, Chitroub, Salim, Zeroual, Abdelhakim.  2021.  Eigen-Fingerprints-Based Remote Authentication Cryptosystem. 2021 International Conference on Recent Advances in Mathematics and Informatics (ICRAMI). :1—6.
Nowadays, biometric is a most technique to authenticate /identify human been, because its resistance against theft, loss or forgetfulness. However, biometric is subject to different transmission attacks. Today, the protection of the sensitive biometric information is a big challenge, especially in current wireless networks such as internet of things where the transmitted data is easy to sniffer. For that, this paper proposes an Eigens-Fingerprint-based biometric cryptosystem, where the biometric feature vectors are extracted by the Principal Component Analysis technique with an appropriate quantification. The key-binding principle incorporated with bit-wise and byte-wise correcting code is used for encrypting data and sharing key. Several recognition rates and computation time are used to evaluate the proposed system. The findings show that the proposed cryptosystem achieves a high security without decreasing the accuracy.
Cooley, Rafer, Cutshaw, Michael, Wolf, Shaya, Foster, Rita, Haile, Jed, Borowczak, Mike.  2021.  Comparing Ransomware using TLSH and @DisCo Analysis Frameworks. 2021 IEEE International Conference on Big Data (Big Data). :2084—2091.
Modern malware indicators utilized by the current top threat feeds are easily bypassed and generated through enigmatic methods, leading to a lack of detection capabilities for cyber defenders. Static hash-based algorithms such as MD5 or SHA generate indicators that are rendered obsolete by modifying a single byte of the source file. Conversely, fuzzy hash-based algorithms such as SSDEEP and TLSH are more robust to alterations of source information; however, these methods often utilize context boundaries that are hard to define or not based on meaningful information. In previous work, a custom binary analysis tool was created called @DisCo. In this study, four current ransomware campaigns were analyzed using TLSH fuzzy hashing and the @DisCo tool. While TLSH works on the binary level of the entire program, @DisCo works at an intermediate function level. The results from each analysis method were compared to provide validation between the two as well as introduce a narrative for using combinations of these types of methods for the creation of stronger indicators of compromise.
Korenda, Ashwija Reddy, Afghah, Fatemeh, Razi, Abolfazl, Cambou, Bertrand, Begay, Taylor.  2021.  Fuzzy Key Generator Design using ReRAM-Based Physically Unclonable Functions. 2021 IEEE Physical Assurance and Inspection of Electronics (PAINE). :1—7.
Physical unclonable functions (PUFs) are used to create unique device identifiers from their inherent fabrication variability. Unstable readings and variation of the PUF response over time are key issues that limit the applicability of PUFs in real-world systems. In this project, we developed a fuzzy extractor (FE) to generate robust cryptographic keys from ReRAM-based PUFs. We tested the efficiency of the proposed FE using BCH and Polar error correction codes. We use ReRAM-based PUFs operating in pre-forming range to generate binary cryptographic keys at ultra-low power with an objective of tamper sensitivity. We investigate the performance of the proposed FE with real data using the reading of the resistance of pre-formed ReRAM cells under various noise conditions. The results show a bit error rate (BER) in the range of 10−5 for the Polar-codes based method when 10% of the ReRAM cell array is erroneous at Signal to Noise Ratio (SNR) of 20dB.This error rate is achieved by using helper data length of 512 bits for a 256 bit cryptographic key. Our method uses a 2:1 ratio for helper data and key, much lower than the majority of previously reported methods. This property makes our method more robust against helper data attacks.
Samy, Salma, Banawan, Karim, Azab, Mohamed, Rizk, Mohamed.  2021.  Smart Blockchain-based Control-data Protection Framework for Trustworthy Smart Grid Operations. 2021 IEEE 12th Annual Information Technology, Electronics and Mobile Communication Conference (IEMCON). :0963—0969.
The critical nature of smart grids (SGs) attracts various network attacks and malicious manipulations. Existent SG solutions are less capable of ensuring secure and trustworthy operation. This is due to the large-scale nature of SGs and reliance on network protocols for trust management. A particular example of such severe attacks is the false data injection (FDI). FDI refers to a network attack, where meters' measurements are manipulated before being reported in such a way that the energy system takes flawed decisions. In this paper, we exploit the secure nature of blockchains to construct a data management framework based on public blockchain. Our framework enables trustworthy data storage, verification, and exchange between SG components and decision-makers. Our proposed system enables miners to invest their computational power to verify blockchain transactions in a fully distributed manner. The mining logic employs machine learning (ML) techniques to identify the locations of compromised meters in the network, which are responsible for generating FDI attacks. In return, miners receive virtual credit, which may be used to pay their electric bills. Our design circumvents single points of failure and intentional FDI attempts. Our numerical results compare the accuracy of three different ML-based mining logic techniques in two scenarios: focused and distributed FDI attacks for different attack levels. Finally, we proposed a majority-decision mining technique for the practical case of an unknown FDI attack level.
Emadi, Hamid, Clanin, Joe, Hyder, Burhan, Khanna, Kush, Govindarasu, Manimaran, Bhattacharya, Sourabh.  2021.  An Efficient Computational Strategy for Cyber-Physical Contingency Analysis in Smart Grids. 2021 IEEE Power & Energy Society General Meeting (PESGM). :1—5.
The increasing penetration of cyber systems into smart grids has resulted in these grids being more vulnerable to cyber physical attacks. The central challenge of higher order cyber-physical contingency analysis is the exponential blow-up of the attack surface due to a large number of attack vectors. This gives rise to computational challenges in devising efficient attack mitigation strategies. However, a system operator can leverage private information about the underlying network to maintain a strategic advantage over an adversary equipped with superior computational capability and situational awareness. In this work, we examine the following scenario: A malicious entity intrudes the cyber-layer of a power network and trips the transmission lines. The objective of the system operator is to deploy security measures in the cyber-layer to minimize the impact of such attacks. Due to budget constraints, the attacker and the system operator have limits on the maximum number of transmission lines they can attack or defend. We model this adversarial interaction as a resource-constrained attacker-defender game. The computational intractability of solving large security games is well known. However, we exploit the approximately modular behaviour of an impact metric known as the disturbance value to arrive at a linear-time algorithm for computing an optimal defense strategy. We validate the efficacy of the proposed strategy against attackers of various capabilities and provide an algorithm for a real-time implementation.
Singh, Jagdeep, Behal, Sunny.  2021.  A Novel Approach for the Detection of DDoS Attacks in SDN using Information Theory Metric. 2021 8th International Conference on Computing for Sustainable Global Development (INDIACom). :512—516.
Internet always remains the target for the cyberattacks, and attackers are getting equipped with more potent tools due to the advancement of technology to preach the security of the Internet. Industries and organizations are sponsoring many projects to avoid these kinds of problems. As a result, SDN (Software Defined Network) architecture is becoming an acceptable alternative for the traditional IP based networks which seems a better approach to defend the Internet. However, SDN is also vulnerable to many new threats because of its architectural concept. SDN might be a primary target for DoS (Denial of Service) and DDoS (Distributed Denial of Service) attacks due to centralized control and linking of data plane and control plane. In this paper, the we propose a novel technique for detection of DDoS attacks using information theory metric. We compared our approach with widely used Intrusion Detection Systems (IDSs) based on Shannon entropy and Renyi entropy, and proved that our proposed methodology has more power to detect malicious flows in SDN based networks. We have used precision, detection rate and FPR (False Positive Rate) as performance parameters for comparison, and validated the methodology using a topology implemented in Mininet network emulator.
Boutaib, Sofien, Elarbi, Maha, Bechikh, Slim, Palomba, Fabio, Said, Lamjed Ben.  2021.  A Possibilistic Evolutionary Approach to Handle the Uncertainty of Software Metrics Thresholds in Code Smells Detection. 2021 IEEE 21st International Conference on Software Quality, Reliability and Security (QRS). :574—585.
A code smells detection rule is a combination of metrics with their corresponding crisp thresholds and labels. The goal of this paper is to deal with metrics' thresholds uncertainty; as usually such thresholds could not be exactly determined to judge the smelliness of a particular software class. To deal with this issue, we first propose to encode each metric value into a binary possibility distribution with respect to a threshold computed from a discretization technique; using the Possibilistic C-means classifier. Then, we propose ADIPOK-UMT as an evolutionary algorithm that evolves a population of PK-NN classifiers for the detection of smells under thresholds' uncertainty. The experimental results reveal that the possibility distribution-based encoding allows the implicit weighting of software metrics (features) with respect to their computed discretization thresholds. Moreover, ADIPOK-UMT is shown to outperform four relevant state-of-art approaches on a set of commonly adopted benchmark software systems.
2022-09-16
Mishra, Suman, Radhika, K, Babu, Y.Murali Mohan.  2021.  Error Detection And Correction In TCAMS Based SRAM. 2021 6th International Conference on Signal Processing, Computing and Control (ISPCC). :283—287.
Ternary content addressable memories (TCAMs) widely utilized in network systems to enforce the labeling of packets. For example, they are used for packet forwarding, security, and software-defined networks (SDNs). TCAMs are typically deployed as standalone instruments or as an embedded intellectual property component on application-specific integrated circuits. However, field-programmable gate arrays (FPGAs) do not have TCAM bases. However, FPGAs’ versatility allows them to appeal for SDN deployment, and most FPGA vendors have SDN production kits. Those need to help TCAM features and then simulate TCAMs using the FPGA logic blocks. Several methods to reproduction TCAMs on FPGAs have been introduced in recent years. Some of them use a huge multiple storage blocks within modern FPGAs to incorporate TCAMs. A trouble while remembrances are that soft errors that corrupt stored bits can affect them. Memories may be covered by a parity test to identify errors or by an error correction code, although this involves extra bits in a word frame. This brief considers memory security used to simulate TCAMs. It is shown in particular that by leveraging the assumption its part of potential memory information is true, most single-bit errors can be resolved when memoirs are emulated with a parity bit.
Cheng, Junyuan, Jiang, Xue-Qin, Bai, Enjian, Wu, Yun, Hai, Han, Pan, Feng, Peng, Yuyang.  2021.  Rate Adaptive Reconciliation Based on Reed-Solomon Codes. 2021 6th International Conference on Communication, Image and Signal Processing (CCISP). :245—249.
Security of physical layer key generation is based on the randomness and reciprocity of wireless fading channel, which has attracted more and more attention in recent years. This paper proposes a rate adaptive key agreement scheme and utilizes the received signal strength (RSS) of the channel between two wireless devices to generate the key. In conventional information reconciliation process, the bit inconsistency rate is usually eliminated by using the filter method, which increases the possibility of exposing the generated key bit string. Building on the strengths of existing secret key extraction approaches, this paper develops a scheme that uses Reed-Solomon (RS) codes, one of forward error correction channel codes, for information reconciliation. Owing to strong error correction performance of RS codes, the proposed scheme can solve the problem of inconsistent key bit string in the process of channel sensing. At the same time, the composition of RS codes can help the scheme realize rate adaptation well due to the construction principle of error correction code, which can freely control the code rate and achieve the reconciliation method of different key bit string length. Through experiments, we find that when the number of inconsistent key bits is not greater than the maximum error correction number of RS codes, it can well meet the purpose of reconciliation.
Bolshakov, Alexander, Zhila, Anastasia.  2021.  Fuzzy Logic Data Protection Management. 2021 28th Conference of Open Innovations Association (FRUCT). :35—40.
This article discusses the problem of information security management in computer systems and describes the process of developing an algorithm that allows to determine measures to protect personal data. The organizational and technical measures formulated by the FSTEC are used as measures.
Simankov, Vladimir S., Buchatskiy, Pavel Yu., Shopin, Andrey V., Teploukhov, Semen V., Buchatskaya, Victoria V..  2021.  An Approach to Identifying the Type of Uncertainty of Initial Information Based on the Theory of Fuzzy Logic. 2021 XXIV International Conference on Soft Computing and Measurements (SCM). :150—153.
The article discusses an approach to identifying the uncertainty of initial information based on the theory of fuzzy logic. A system of criteria for initial information is proposed, calculated on the basis of the input sample, and characterizing the measure of uncertainty present in the system. The basic requirements for the choice of membership functions of the fuzzy inference system are indicated and the final integrated output membership function is obtained, which describes the type of uncertainty of the initial information.
2022-09-09
Benabdallah, Chaima, El-Amraoui, Adnen, Delmotte, François, Frikha, Ahmed.  2020.  An integrated rough-DEMA℡ method for sustainability risk assessment in agro-food supply chain. 2020 5th International Conference on Logistics Operations Management (GOL). :1—9.
In the recent years, sustainability has becoming an important topic in agro-food supply chain. Moreover, these supply chains are more vulnerable due to different interrelated risks from man-made and natural disasters. However, most of the previous studies consider less about interrelation in assessing sustainability risks. The purpose of this research is to develop a framework to assess supply chain sustainability risks by rnking environmental risks, economic risks, social risks and operational risks. To solve this problem, the proposed methodology is an integrated rough decision- making and trial evaluation laboratory (DEMA℡) method that consider the interrelationship between different risks and the group preference diversity. In order to evaluate the applicability of the proposed method, a real-world case study of Tunisian agro-food company is presented. The results show that the most important risks are corruption, inflation and uncertainty in supply and demand.
Langer, Martin, Heine, Kai, Bermbach, Rainer, Sibold, Dieter.  2021.  Extending the Network Time Security Protocol for Secure Communication between Time Server and Key Establishment Server. 2021 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFCS). :1—5.
This work describes a concept for extending the Network Time Security (NTS) protocol to enable implementation- independent communication between the NTS key establishment (NTS-KE) server and the connected time server(s). It Alls a specification gap left by RFC 8915 for securing the Network Time Protocol (NTP) and enables the centralized and public deployment of an NTS key management server that can support both secured NTP and secured PTP.
2022-08-26
Xia, Hongbing, Bao, Jinzhou, Guo, Ping.  2021.  Asymptotically Stable Fault Tolerant Control for Nonlinear Systems Through Differential Game Theory. 2021 17th International Conference on Computational Intelligence and Security (CIS). :262—266.
This paper investigates an asymptotically stable fault tolerant control (FTC) method for nonlinear continuous-time systems (NCTS) with actuator failures via differential game theory (DGT). Based on DGT, the FTC problem can be regarded as a two-player differential game problem with control player and fault player, which is solved by utilizing adaptive dynamic programming technique. Using a critic-only neural network, the cost function is approximated to obtain the solution of the Hamilton-Jacobi-Isaacs equation (HJIE). Then, the FTC strategy can be obtained based on the saddle point of HJIE, and ensures the satisfactory control performance for NCTS. Furthermore, the closed-loop NCTS can be guaranteed to be asymptotically stable, rather than ultimately uniformly bounded in corresponding existing methods. Finally, a simulation example is provided to verify the safe and reliable fault tolerance performance of the designed control method.
Zhang, Fan, Bu, Bing.  2021.  A Cyber Security Risk Assessment Methodology for CBTC Systems Based on Complex Network Theory and Attack Graph. 2021 7th Annual International Conference on Network and Information Systems for Computers (ICNISC). :15—20.

Cyber security risk assessment is very important to quantify the security level of communication-based train control (CBTC) systems. In this paper, a methodology is proposed to assess the cyber security risk of CBTC systems that integrates complex network theory and attack graph method. On one hand, in order to determine the impact of malicious attacks on train control, we analyze the connectivity of movement authority (MA) paths based on the working state of nodes, the connectivity of edges. On the other hand, attack graph is introduced to quantify the probabilities of potential attacks that combine multiple vulnerabilities in the cyber world of CBTC. Experiments show that our methodology can assess the security risks of CBTC systems and improve the security level after implementing reinforcement schemes.

Kreher, Seth E., Bauer, Bruno S., Klemmer, Aidan W., Rousculp, Christopher L., Starrett, Charles E..  2021.  The Surprising Role of Equation of State Models In Electrically Exploding Metal Rod MHD Simulations. 2021 IEEE International Conference on Plasma Science (ICOPS). :1—1.
The fundamental limits of high-current conduction and response of metal conductors to large, fast current pulses are of interest to high-speed fuses, exploding wires and foils, and magnetically driven dynamic material property and inertial confinement fusion experiments. A collaboration between the University of Nevada, Reno, University of New Mexico, and Sandia National Laboratory has fielded an electrically thick (R 400-μm \textbackslashtextgreater skin-depth) cylindrical metal rod platform in a Z-pinch configuration driven by the Sandia 100-ns, 900-kA Mykonos linear transformer driver 1 . Photonic Doppler velocimetry (PDV) measuring the expansion velocity of the uncoated surface of aluminum rods 2 was used to benchmark equation of state (EOS) and electrical conductivity models used in magnetohydrodynamics simulations using the Los Alamos National Laboratory (LANL) code FLAG 3 . The metal surface was found to expand along the liquid-vapor coexistence curve in density-temperature space for 90 ns of the rod’s expansion for both tabular EOSs with Van der Waals loops and with Maxwell constructions under the vapor dome. As the slope of the coexistence curve varies across EOS models, the metal surface in simulation was found to heat and expand at different rates depending on the model used. The expansion velocities associated with EOS models were then compared against the PDV data to validate the EOS used in simulations of similar systems. Here, the most recent aluminum EOS (SESAME 93722) 4 was found to drive a simulated velocity that best compared with the experimental data due to its relatively steep coexistence curve and high critical point.
Gomez, Matthew R., Slutz, S.A., Jennings, C.A., Weis, M.R., Lamppa, D.C., Harvey-Thompson, A.J., Geissel, M., Awe, T.J., Chandler, G.A., Crabtree, J.A. et al..  2021.  Developing a Platform to Enable Parameter Scaling Studies in Magnetized Liner Inertial Fusion Experiments. 2021 IEEE International Conference on Plasma Science (ICOPS). :1—1.
Magnetized Liner Inertial Fusion (MagLIF) is a magneto-inertial fusion concept that relies on fuel magnetization, laser preheat, and a magnetically driven implosion to produce fusion conditions. In MagLIF, the target is a roughly 10 mm long, 5 mm diameter, 0.5 mm thick, cylindrical beryllium shell containing 1 mg/cm 3 D 2 gas. An axial magnetic field on the order of 10 T is applied to the target, and several kJ of laser energy is deposited into the fuel. Up to 20 MA of current is driven axially through the beryllium target, causing it to implode over approximately 100 ns. The implosion produces a 100-μm diameter, 8-mm tall fuel column with a burn-averaged ion temperature of several keV, that generates 10 11 -10 13 DD neutrons.
Zimmer, D., Conti, F., Beg, F., Gomez, M. R., Jennings, C. A., Myers, C. E., Bennett, N..  2021.  Effects of Applied Axial Magnetic Fields on Current Coupling in Maglif Experiments on the Z Machine. 2021 IEEE International Conference on Plasma Science (ICOPS). :1—1.
The Z machine is a pulsed power generator located at Sandia National Laboratories in Albuquerque, New Mexico. It is capable of producing a \textbackslashtextgreater20 MA current pulse that is directed onto an experimental load. While a diverse array of experiments are conducted on the Z machine, including x-ray production and dynamic materials science experiments, the focus of this presentation are the Magnetic Liner Inertial Fusion (MagLIF) experiments. In these experiments, an axial magnetic field is applied to the load region, where a cylindrical, fuel-filled metal liner is imploded. We explore the effects of this field on the ability to efficiently couple the generator current to the load, and the extent to which this field interrupts the magnetic insulation of the inner-most transmission line. We find that at the present-day applied field values, the effects of the applied field on current coupling are negligible. Estimates of the potential impact on current coupling of the larger applied field values planned for future experiments are also given. Shunted current is measured with B-dot probes and flyer velocimetry techniques. Analytical calculations, 2D particle-in-cell simulations, and experimental measurements will be presented.
Lewis, William E., Knapp, Patrick F., Slutz, Stephen A., Schmit, Paul F., Chandler, Gordon A., Gomez, Matthew R., Harvey-Thompson, Adam J., Mangan, Michael A., Ampleford, David J., Beckwith, Kristian.  2021.  Deep Learning Enabled Assessment of Magnetic Confinement in Magnetized Liner Inertial Fusion. 2021 IEEE International Conference on Plasma Science (ICOPS). :1—1.
Magnetized Liner Inertial Fusion (MagLIF) is a magneto-inertial fusion (MIF) concept being studied on the Z-machine at Sandia National Laboratories. MagLIF relies on quasi-adiabatic heating of a gaseous deuterium (DD) fuel and flux compression of a background axially oriented magnetic field to achieve fusion relevant plasma conditions. The magnetic flux per fuel radial extent determines the confinement of charged fusion products and is thus of fundamental interest in understanding MagLIF performance. It was recently shown that secondary DT neutron spectra and yields are sensitive to the magnetic field conditions within the fuel, and thus provide a means by which to characterize the magnetic confinement properties of the fuel. 1 , 2 , 3 We utilize an artificial neural network to surrogate the physics model of Refs. [1] , [2] , enabling Bayesian inference of the magnetic confinement parameter for a series of MagLIF experiments that systematically vary the laser preheat energy deposited in the target. This constitutes the first ever systematic experimental study of the magnetic confinement properties as a function of fundamental inputs on any neutron-producing MIF platform. We demonstrate that the fuel magnetization decreases with deposited preheat energy in a fashion consistent with Nernst advection of the magnetic field out of the hot fuel and diffusion into the target liner.
Bahrami, Mohammad, Jafarnejadsani, Hamidreza.  2021.  Privacy-Preserving Stealthy Attack Detection in Multi-Agent Control Systems. 2021 60th IEEE Conference on Decision and Control (CDC). :4194—4199.
This paper develops a glocal (global-local) attack detection framework to detect stealthy cyber-physical attacks, namely covert attack and zero-dynamics attack, against a class of multi-agent control systems seeking average consensus. The detection structure consists of a global (central) observer and local observers for the multi-agent system partitioned into clusters. The proposed structure addresses the scalability of the approach and the privacy preservation of the multi-agent system’s state information. The former is addressed by using decentralized local observers, and the latter is achieved by imposing unobservability conditions at the global level. Also, the communication graph model is subject to topology switching, triggered by local observers, allowing for the detection of stealthy attacks by the global observer. Theoretical conditions are derived for detectability of the stealthy attacks using the proposed detection framework. Finally, a numerical simulation is provided to validate the theoretical findings.