The second-generation Shifted Boundary Method and its numerical analysis

Recently, the Shifted Boundary Method (SBM) was proposed within the class of unfitted (or immersed, or embedded) finite element methods. By reformulating the original boundary value problem over a surrogate (approximate) computational domain, the SBM avoids integration over cut cells and the associated problematic issues regarding numerical stability and matrix conditioning. Accuracy is maintained by modifying the original boundary conditions using Taylor expansions. Hence the name of the method, that shifts the location and values of the boundary conditions. In this article, we present enhanced variational SBM formulations for the Poisson and Stokes problems with improved flexibility and robustness. These simplified variational forms allow to relax some of the assumptions required by the mathematical proofs of stability and convergence of earlier implementations. First, we show that these new SBM implementations can be proved asymptotically stable and convergent even without the rather restrictive assumption that the inner product between the normals to the true and surrogate boundaries is positive. Second, we show that it is not necessary to introduce a stabilization term involving the tangential derivatives of the solution at Dirichlet boundaries, therefore avoiding the calibration of an additional stabilization parameter. Finally, we prove enhanced L2-estimates without the cumbersome assumption – of earlier proofs – that the surrogate domain is convex. Instead we rely on a conventional assumption that the boundary of the true domain is smooth, which can also be replaced by requiring convexity of the true domain. The aforementioned improvements open the way to a more general and efficient implementation of the Shifted Boundary Method, particularly in complex three-dimensional geometries. We complement these theoretical developments with numerical experiments in two and three dimensions

Software Protection

A computer system's security can be compromised in many ways a denial-of-service attack can make a server inoperable, a worm can destroy a user's private data, or an eavesdrop per can reap financial rewards by inserting himself in the communication link between a customer and her bank through a man-in-the-middle (MITM) attack. What all these scenarios have in common is that the adversary is an untrusted entity that attacks a system from the outside-we assume that the computers under attack are operated by benign and trusted users. But if we remove this assumption, if we allow anyone operating a computer system- from system administrators down to ordinary users-to compromise that system's security, we find ourselves in a scenario that has received comparatively little attention. Methods for protecting against MATE attacks are variously known as anti-tamper techniques, digital asset protection, or, more

Investigating the Security of EV Charging Mobile Applications As an Attack Surface

The adoption rate of EVs has witnessed a significant increase in recent years driven by multiple factors, chief among which is the increased flexibility and ease of access to charging infrastructure. To improve user experience, increase system flexibility and commercialize the charging process, mobile applications have been incorporated into the EV charging ecosystem. EV charging mobile applications allow consumers to remotely trigger actions on charging stations and use functionalities such as start/stop charging sessions, pay for usage, and locate charging stations, to name a few. In this paper, we study the security posture of the EV charging ecosystem against remote attacks, which exploit the insecurity of the EV charging mobile applications as an attack surface. We leverage a combination of static and dynamic analysis techniques to analyze the security of widely used EV charging mobile applications. Our analysis of 31 widely used mobile applications and their interactions with various components such as the cloud management systems indicate the lack of user/vehicle verification and improper authorization for critical functions, which lead to remote (dis)charging session hijacking and Denial of Service (DoS) attacks against the EV charging station. Indeed, we discuss specific remote attack scenarios and their impact on the EV users. More importantly, our analysis results demonstrate the feasibility of leveraging existing vulnerabilities across various EV charging mobile applications to perform wide-scale coordinated remote charging/discharging attacks against the connected critical infrastructure (e.g., power grid), with significant undesired economical and operational implications. Finally, we propose counter measures to secure the infrastructure and impede adversaries from performing reconnaissance and launching remote attacks using compromised accounts

NGS-Based Diagnosis of Treatable Neurogenetic Disorders in Adults: Opportunities and Challenges.

The identification of neurological disorders by next-generation sequencing (NGS)-based gene panels has helped clinicians understand the underlying physiopathology, resulting in personalized treatment for some rare diseases. While the phenotype of distinct neurogenetic disorders is generally well-known in childhood, in adulthood, the phenotype can be unspecific and make the standard diagnostic approach more complex. Here we present three unrelated adults with various neurological manifestations who were successfully diagnosed using NGS, allowing for the initiation of potentially life-changing treatments. A 63-year-old woman with progressive cognitive decline, pyramidal signs, and bilateral cataract was treated by chenodeoxycholic acid following the diagnosis of cerebrotendinous xanthomatosis due to a homozygous variant in CYP27A1. A 32-year-old man with adult-onset spastic paraplegia, in whom a variant in ABCD1 confirmed an X-linked adrenoleukodystrophy, was treated with corticoids for adrenal insufficiency. The third patient, a 28-year-old woman with early-onset developmental delay, epilepsy, and movement disorders was treated with a ketogenic diet following the identification of a variant in SLC2A1, confirming a glucose transporter type 1 deficiency syndrome. This case study illustrates the challenges in the timely diagnosis of medically actionable neurogenetic conditions, but also the considerable potential for improving patient health through modern sequencing technologies

Collaborative Simulation for Hybrid Networks

An experiment for using more than one simulation of sub-networks collaborating as a single large simulation is suggested, based on work with a similar situation. The background and relevant details of the initial solution are described to provide an outline for the solution. Work on this method will help development of simulations for hybrid networks, where newer pieces may be added to the simulation without having to build a large, monolithic and a site-centric development effor

A Formal Study of the Privacy Concerns in Biometric-Based Remote Authentication Schemes

With their increasing popularity in cryptosystems, biometrics have attracted more and more attention from the information security community. However, how to handle the relevant privacy concerns remains to be troublesome. In this paper, we propose a novel security model to formalize the privacy concerns in biometric-based remote authentication schemes. Our security model covers a number of practical privacy concerns such as identity privacy and transaction anonymity, which have not been formally considered in the literature. In addition, we propose a general biometric-based remote authentication scheme and prove its security in our security model