Numerical simulation of shaped charge jet penetrating a plate using smoothed particle hydrodynamics

The shaped charge jet has a stronger penetration effect onto the structure than normal charges. The SPH method with mesh-free and Lagrange properties has an advantage to solve extremely dynamic problems, such as large-deformation, moving interface and multiphase mixing and so on. Therefore, the SPH method is applied to simulate shaped charge detonation, jet formation and its penetration into a plate. And a SPH model of the shaped charge penetrating the plate is established. Firstly, the simulation of the shaped charge detonation is conducted to study the shock wave propagation and underwater explosion shock loading. Secondly, the formation of the metal jet is studied, and the jet velocity and the pressure are investigated in detail. Finally, the damage characteristics of the plate subjected to the metal jet and underwater explosion shock loading are discussed. The whole analysis and conclusions provide a reference for the structural design of shaped charge warheads

Method and system for detecting common attributes of network upgrades

A system and method identify a set of rules for determining a commonality of attributes across different behavior changes for a network. The system performs the method by receiving a set of data correlating network triggers to performance changes of one or more network devices. The set of data further includes an indication of a sign of the performance change for each of the network devices based on the triggers. The method further includes extracting a set of rules relating to a set of relationships between the triggers and the performance changes. The rules identify a commonality of the performance changes for multiple network devices based on the triggers.Board of Regents, University of Texas Syste

Oxidation kinetics of a Ni-Cu based cermet at high temperature

The oxidation kinetics of a cermet composed of Ni–Cu alloy and nickel ferrite was studied by thermogravimetry at 960 °C under oxygen in the range 0.5–77 kPa. After an initial mass increase up to 15 g/m2 due to oxidation of surface metallic particles, the mass change was attributed to both outwards NiO growth and internal oxidation. Above 40 g/m2, the NiO scale thickness remained constant and the oxidation kinetics followed a complete parabolic law. The variations of the kinetic rate with oxygen partial pressure allowed to propose mechanisms, rate-controlling steps and kinetic laws in both transient and long term oxidation periods

Disappearance of Transverse Flow in Central Collisions for Heavier Nuclei

For the first time, mass dependence of balance energy only for heavier systems has been studied. Our results are in excellent agreement with the data which allow us to predict the balance energy of U+U, for the first time, around 37-39 MeV/nucleon. Also our results indicate a hard equation of state along with nucleon-nucleon cross-section around 40 mb.Comment: 4 pages, 3 figures, submitted to Phys. Rev. Let

ALDB: Debugging Alloy Models of Behavioural Requirements

© 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Declarative modelling languages, such as Alloy, are becoming popular for describing behavioural requirements very early in system development because automated analysis of these models provides valuable feedback. Typically, these languages are supported by constraint solvers (SAT, SMT) for providing instances or model checking properties. However, a user can quickly find simple bugs and gain confidence in their model by concretely simulating steps of the transition system. We present ALDB: a debugger for models of transition systems written in the Alloy language. It provides a familiar debugging interface to walk around in the behaviour of the model, enabling users to quickly explore scenarios, find errors via concrete simulation, and incrementally build up to bounded model checking.Natural Sciences and Engineering Research Council of Canada

Privacy Risks of Securing Machine Learning Models against Adversarial Examples

The arms race between attacks and defenses for machine learning models has come to a forefront in recent years, in both the security community and the privacy community. However, one big limitation of previous research is that the security domain and the privacy domain have typically been considered separately. It is thus unclear whether the defense methods in one domain will have any unexpected impact on the other domain. In this paper, we take a step towards resolving this limitation by combining the two domains. In particular, we measure the success of membership inference attacks against six state-of-the-art defense methods that mitigate the risk of adversarial examples (i.e., evasion attacks). Membership inference attacks determine whether or not an individual data record has been part of a model's training set. The accuracy of such attacks reflects the information leakage of training algorithms about individual members of the training set. Adversarial defense methods against adversarial examples influence the model's decision boundaries such that model predictions remain unchanged for a small area around each input. However, this objective is optimized on training data. Thus, individual data records in the training set have a significant influence on robust models. This makes the models more vulnerable to inference attacks. To perform the membership inference attacks, we leverage the existing inference methods that exploit model predictions. We also propose two new inference methods that exploit structural properties of robust models on adversarially perturbed data. Our experimental evaluation demonstrates that compared with the natural training (undefended) approach, adversarial defense methods can indeed increase the target model's risk against membership inference attacks.Comment: ACM CCS 2019, code is available at https://github.com/inspire-group/privacy-vs-robustnes

Case Report: A long-term survival case of diffuse large B-cell lymphoma with left ventricular infiltration and spinal cord compression

BackgroundDiffuse large B-cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin lymphoma and may occur with lymph node and/or extranodal involvement. However, DLBCL with intracardiac mass is exceedingly rare. In the reported literature, the intracardiac infiltration of DLBCL mostly involves the right ventricle. Lymphoma that invades the heart has an aggressive nature, with symptoms that are easily ignored initially and can lead to multiple complications in severe cases, resulting in a poor prognosis. Early screening and diagnosis may significantly improve the survival rate. Early diagnosis may significantly improve outcomes.Case summaryWe presented a 68-year-old woman with back pain. PET/CT suggested increased FDG metabolism in the left ventricle, right adrenal gland, right erector spinae intramuscularis, multiple bones and multiple lymph nodes. Contrast-enhanced ultrasound showed a left ventricular apical mass with ventricular septum thickening. Cardiac MRI suggested a 1.6*1.1*2.1 cm mass in the apical-central portion of the left ventricle. Biopsy of the right neck mass confirmed the pathologic diagnosis of diffuse large B-cell lymphoma. However, before the pathologic diagnosis was confirmed, the patient was paralyzed due to spinal cord compression caused by the progression of bone metastases. Subsequently, pathology confirmed the diagnosis of diffuse large B-cell lymphoma, and rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) was treated immediately as first-line therapy. In addition, glucocorticoids and mannitol dehydration were administered to relieve the symptoms of spinal cord compression. After 8 cycles of R-CHOP, the tumor at all sites had almost complete regression. The patient was able to walk normally and had no tumor-related symptoms.ConclusionsWe present a case of DLBCL with a very high tumor load that involved multiple organs, including the left ventricle, but exhibited no cardiac-related symptoms. The combination of various imaging modalities is valuable for the diagnosis of cardiac infiltration. The mass in the left ventricle almost completely regressed after R-CHOP treatment, and no recurrence has occurred in the 5 years of follow-up so far