80 research outputs found

    Applying system dynamics to model advanced persistent threats

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    © 2019 Association for Computing Machinery. System dynamics (SD) concept has been successfully applied to analyze issues that are non-linear, complex, and dynamic in disciplines namely social sciences and technology. However, its application to cyber security issues especially threats that involves multiple variables interacting with the technical as well as the organizational domain is lacking. In this respect, Advanced Persistent Threat (APT) is regarded as a highly targeted and sophisticated attack using zero-day malware, stealth, and multiple advanced techniques to gain entry and maintain its presence inside organizational network unnoticed. Being a threat that exploits technical as well as organizational vulnerabilities, preventing it at the security perimeter and, detecting it once it enters the system is a challenge till date. To demonstrate the application of SD in identifying and analyzing the effect of each of the variables, we took the Equinox data breach as a case study. The variables leading to the breach were identified, entered into Vensim software and simulated to get the results. Through this exercise, we could identify seven key independent management variables for the technical security and three key independent variables for records breach. This research being the foremost study to apply SD to APT, we presume that by modelling APT attacks using SD through a case study this paper, thus provides insights into the dynamics of the threat. Furthermore, it suggests \u27what if\u27 strategies to minimize APT risks thereby reduce the extent of damages should an APT attack occur

    Control Demonstration of Multiple Doubly-Fed Induction Motors for Hybrid Electric Propulsion

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    The Convergent Aeronautics Solutions (CAS) High Voltage-Hybrid Electric Propulsion (HVHEP) task was formulated to support the move into future hybrid-electric aircraft. The goal of this project is to develop a new AC power architecture to support the needs of higher efficiency and lower emissions. This proposed architecture will adopt the use of the doubly-fed induction machine (DFIM) for propulsor drive motor application.The Convergent Aeronautics Solutions (CAS) High Voltage-Hybrid Electric Propulsion (HVHEP) task was formulated to support the move into future hybrid-electric aircraft. The goal of this project is to develop a new AC power architecture to support the needs of higher efficiency and lower emissions. This proposed architecture will adopt the use of the doubly-fed induction machine (DFIM) for propulsor drive motor application. DFIMs are attractive for several reasons, including but not limited to the ability to self-start, ability to operate sub- and super-synchronously, and requiring only fractionally rated power converters on a per-unit basis depending on the required range of operation. The focus of this paper is based specifically on the presentation and analysis of a novel strategy which allows for independent operation of each of the aforementioned doubly-fed induction motors. This strategy includes synchronization, soft-start, and closed loop speed control of each motor as a means of controlling output thrust; be it concurrently or differentially. The demonstration of this strategy has recently been proven out on a low power test bed using fractional horsepower machines. Simulation and hardware test results are presented in the paper

    Modeling and Control Design for a Turboelectric Single Aisle Aircraft Propulsion System

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    A nonlinear dynamic model with full flight envelope controller is developed for the propulsion system of a partially turboelectric single-aisle aircraft. The propulsion system model consists of two turbofan engines with a large percentage of power extraction, feeding an electric tail fan for boundary layer ingestion. The dynamic model is compared against an existing steady state design model. An electrical system model using a simple power flow approach is integrated into existing modeling tools used for dynamic simulation of the turbomachinery of the vehicle. In addition to the simple power flow model of the electrical system, a more detailed model is used for comparison at a key vehicle transient flight condition. The controller is a gain scheduled proportional-integral type that is examined throughout the flight envelope for performance metrics such as rise time and operability margins. Potential improvements in efficiency for the vehicle are explored by adjusting the power split between the energy used for thrust by the turbofans and that extracted to supply power to the tail fan. Finally, an operability study of the vehicle is conducted using a 900 nautical mile mission profile for a nominal vehicle configuration, a deteriorated propulsion system at the end of its operating life, and an optimized power schedule with improved efficiency

    Impairment of Vowel Articulation as a Possible Marker of Disease Progression in Parkinson's Disease

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    Purpose: The aim of the current study was to survey if vowel articulation in speakers with Parkinson’s disease (PD) shows specific changes in the course of the disease. Method: 67 patients with PD (42 male) and 40 healthy speakers (20 male) were tested and retested after an average time interval of 34 months. Participants had to read a given text as source for subsequent calculation of the triangular vowel space area (tVSA) and vowel articulation index (VAI). Measurement of tVSA and VAI were based upon analysis of the first and second formant of the vowels /a/, /i/and /u / extracted from defined words within the text. Results: At first visit, VAI values were reduced in male and female PD patients as compared to the control group, and showed a further decrease at the second visit. Only in female Parkinsonian speakers, VAI was correlated to overall speech impairment based upon perceptual impression. VAI and tVSA were correlated to gait impairment, but no correlations were seen between VAI and global motor impairment or overall disease duration. tVSA showed a similar reduction in the PD as compared to the control group and was also found to further decline between first and second examination in female, but not in male speakers with PD. Conclusions: Measurement of VAI seems to be superior to tVSA in the description of impaired vowel articulation and its further decline in the course of the disease in PD. Since impairment of vowel articulation was found to be independent fro

    F-state quenching with CH4 for buffer-gas cooled 171Y b+ frequency standard

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    We report that methane, CH4, can be used as an efficient F-state quenching gas for trapped ytterbium ions. The quenching rate coefficient is measured to be (2.8 ± 0.3) × 106 s−1 Torr−1. For applications that use microwave hyperfine transitions of the ground-state 171Y b ions, the CH4 induced frequency shift coefficient and the decoherence rate coefficient are measured as δν/ν = (−3.6 ± 0.1) × 10−6 Torr−1 and 1/T2 = (1.5 ± 0.2) × 105 s−1 Torr−1. In our buffer-gas cooled 171Y b+ microwave clock system, we find that only ≤10−8 Torr of CH4 is required under normal operating conditions to efficiently clear the F-state and maintain ≥85% of trapped ions in the ground state with insignificant pressure shift and collisional decoherence of the clock resonance

    A Call for Action: Increasing Public Awareness of the Māui Dolphin

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    The New Zealand Department of Conservation has experienced difficulties in raising public awareness of the critically endangered Māui dolphin. In order to address this problem, we interviewed Māui dolphin activists and educators to determine ways that individuals and communities can take action to help conserve this species. We also assessed current conservation education strategies and the concept of mātauranga Māori. As an outcome, the team created an educational video, a children’s book and several recommendations in order to increase awareness

    Attack tree analysis for insider threats on the IoT using Isabelle

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    The Internet-of-Things (IoT) aims at integrating small devices around humans. The threat from human insiders in “regular” organisations is real; in a fully-connected world of the IoT, organisations face a substantially more severe security challenge due to unexpected access possibilities and information flow. In this paper, we seek to illustrate and classify insider threats in relation to the IoT (by ‘smart insiders’), exhibiting attack vectors for their characterisation. To model the attacks we apply a method of formal modelling of Insider Threats in the interactive theorem prover Isabelle. On the classified IoT attack examples, we show how this logical approach can be used to make the models more precise and to analyse the previously identified Insider IoT attacks using Isabelle attack tree

    Developing An Insider Threat Training Environment

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    Many cyber security officers are more concerned with outside rather than insider threats because the enemy is generally perceived as being “out there” or beyond the organization. Therefore, defensive actions are readily available once an outside threat is identified (Colwill in Human factors in information security: the insider threat—who can you trust these days? pp. 186–196, 2009 [1]). Contradictory to the ideas of social identification as an “us” and “them,” the greatest enemy may be lurking within one’s own organization. Individuals are considered insiders if they presently have (or at one time had) permission to access an organization’s data or network structures (Greitzer et al. in Secur Priv IEEE 6(1):61–64, 2008 [2]). The concept of the insider threat is considered one of the most difficult situations to deal with in the cybersecurity domain (Hunker and Probst in J Wireless Mobile Netw Ubiquitous Comput Dependable Appl 2(1):4–27, 2011 [3]). The Association of Certified Fraud Examiners has reported two-thirds of fraud and identity thefts are executed by organizations’ employees or other known insiders. They also estimate U.S. companies have lost 5% of revenue to fraudulent insider activities (Randazzo et al. in Insider threat study: illicit cyber activity in the banking and finance sector, 2005 [4]). Insiders have multiple advantages over an outsider. An insider threat is one of the most difficult situations to identify. Therefore, it is critical that training be developed. The first step to effective training is constructing an environment that lends itself to insider threat situations. The present paper describes the process in which one insider threat virtual environment was constructed. A discussion of the considerations and functional features is detailed
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