Neural Network Repair with Reachability Analysis

Safety is a critical concern for the next generation of autonomy that is likely to rely heavily on deep neural networks for perception and control. Formally verifying the safety and robustness of well-trained DNNs and learning-enabled cyber-physical systems (Le-CPS) under adversarial attacks, model uncertainties, and sensing errors is essential for safe autonomy. This research proposes a framework to repair unsafe DNNs in safety-critical systems with reachability analysis. The repair process is inspired by adversarial training which has demonstrated high effectiveness in improving the safety and robustness of DNNs. Different from traditional adversarial training approaches where adversarial examples are utilized from random attacks and may not be representative of all unsafe behaviors, our repair process uses reachability analysis to compute the exact unsafe regions and identify sufficiently representative examples to enhance the efficacy and efficiency of the adversarial training. The performance of our repair framework is evaluated on two types of benchmarks without safe models as references. One is a DNN controller for aircraft collision avoidance with access to training data. The other is a rocket lander where our framework can be seamlessly integrated with the well-known deep deterministic policy gradient (DDPG) reinforcement learning algorithm. The experimental results show that our framework can successfully repair all instances on multiple safety specifications with negligible performance degradation. In addition, to increase the computational and memory efficiency of the reachability analysis algorithm in the framework, we propose a depth-first-search algorithm that combines an existing exact analysis method with an over-approximation approach based on a new set representation. Experimental results show that our method achieves a five-fold improvement in runtime and a two-fold improvement in memory usage compared to exact analysis

Upgrading Therapy Strategy Improves Pregnancy Outcome in Antiphospholipid Syndrome: A Cohort Management Study

The current study evaluates the efficacy and safety of different treatment strategies for pregnant patients with antiphospholipid syndrome. One hundred twenty-seven consecutive pregnancies were assessed; 87 (68.5%) with a history of pregnancy morbidity alone were treated with prophylactic low molecular weight heparin (LMWH) + low-dose aspirin (LDA, 100 mg) (group I) and 40 (31.5%) with a history of thrombosis and/or severe pregnancy complications with therapeutic LMWH + LDA (group II). LMWH doses were increased throughout the pregnancies depending on the patients' weight gain, and treatment was switched to a more intensive one at the first sign of maternal/fetal complications. The study's primary outcome was live births. There were no significant differences in live birth rate between group I (95.4%) and group II (87.5%). Even fetal complication rate was similar in the two groups; group II nevertheless had a higher prevalence of maternal and neonatal complications (p = 0.0005 and p = 0.01, respectively) and registered a significantly lower gestational age at delivery and birth weight (p = 0.0001 and p = 0.0005, respectively). Two patients in group I switched to group II therapy, six patients in group II switched to a more intensive treatment strategy (weekly plasma exchange + fortnightly intravenous immunoglobulins in addition to therapeutic LMWH + LDA). The multivariate analysis uncovered that triple antiphospholipid antibodies positivity was an independent factor leading to a more intensive therapy. All eight switched patients achieved a live birth. Study results revealed that adjusted LMWH doses and switching therapy at first signs of severe pregnancy complications led to a high rate of live births in antiphospholipid syndrome patients

AB0378 UPGRADING THERAPY STRATEGY IMPROVES PREGNANCY OUTCOME IN ANTIPHOSPHOLIPID SYNDROME: A COHORT MANAGEMENT STUDY

Background:While it is generally agreed that pregnant APS patients should receive personalized treatment, evidence-based guidelines for these patients continue to be lacking.Objectives:The current study was designed as a management cohort study aiming to evaluate the efficacy and safety of different treatment strategies for pregnant APS patients in the attempt to provide some practical suggestions for attending physicians.Methods:One-hundred-twenty-seven consecutive pregnancies were assessed; 87 (68.5%) with a history of pregnancy morbidity alone were treated with prophylactic low molecular weight heparin (LMWH)+low-dose aspirin (LDA, 100 mg) [Group I] and 40 (31.5%) with a history of thrombosis and/or severe pregnancy complications with therapeutic LMWH+LDA [Group II]. LMWH doses were increased throughout the pregnancies depending on the patients' weight gain, and treatment was switched to a more intensive one at the first sign of maternal/fetal complications. The study's primary outcome was live births.Results:There were no significant differences in live birth rate between Group I (95.4%) and Group II (87.5%). Even, fetal complication rate was similar in the two groups; the Group II nevertheless had a higher prevalence of maternal and neonatal complications (p=0.0005 and p=0.01, respectively) and registered a significantly lower gestational age at delivery and birth weight (p=0.0001 and p=0.0005, respectively). Two patients in Group I switched to Group II therapy, six patients in Group II switched to a more intensive treatment strategy (weekly plasma exchange+ fortnightly intravenous immunoglobulins in addition to therapeutic LMWH+LDA). Comparison of the clinical and laboratory characteristics between patients who had shifted to a more intensive therapy and those who did not showed a significant prevalence of history of thrombosis ± pregnancy morbidity (p=0.02, OR 5.96, 95% CI 1.33-26.62) previous pregnancy complications (p=0.02, OR 8.32, 95% CI 1.67-41.3), triple aPL positivity (p <0.0001, OR 97.13, 95% CI 10.6-890) and pregnancy complications (p<0.0001, OR 197,7, 95% CI 10.57-3699) in upgrading group, instead single aPL positivity significantly prevailed (p=0.003, OR 0.06, 95% CI 0.008-0.58) in non-upgrading group. Logistic regression analysis demonstrated that triple aPL positivity was an independent factor for switching to a more effective therapy protocol (p <0.0001, OR 98, 95% CI 10.7-897.54). All eight switched patients achieved a live birth.Conclusion:Using adjusted LMWH doses and upgrading therapy at the first signs of pregnancy complications led to a high rate of live births in a relatively large group of APS patients. The study outlines the criteria for prescribing appropriate therapy for various subsets of these patients and for switching/upgrading the treatment protocol when it is no longer sufficient. Unfortunately, for the moment there are no evidence-based guidelines on the ideal additional treatment in refractory to conventional therapy APS patients. The present results will hopefully help point the direction of future clinical trials investigating the efficacy and safety of the different therapies on large numbers of APS pregnant patients in order to identify the benefits and limits of different treatment strategies administered from the beginning of pregnancy.Disclosure of Interests:Ariela Hoxha Speakers bureau: Celgene, UCB, Novartis, Sanofi, Werfen, Maria Favaro: None declared, Antonia Calligaro: None declared, Teresa Del Ross: None declared, Alessandra Teresa Ruffatti: None declared, Chiara Infantolino: None declared, Marta Tonello: None declared, Elena Mattia: None declared, Amelia Ruffatti: None declare

Consistent Group and Coset Reductions of the Bosonic String

Dimensional reductions of pure Einstein gravity on cosets other than tori are inconsistent. The inclusion of specific additional scalar and p-form matter can change the situation. For example, a D-dimensional Einstein-Maxwell-dilaton system, with a specific dilaton coupling, is known to admit a consistent reduction on S^2= SU(2)/U(1), of a sort first envisaged by Pauli. We provide a new understanding, by showing how an S^3=SU(2) group-manifold reduction of (D+1)-dimensional Einstein gravity, of a type first indicated by DeWitt, can be broken into in two steps; a Kaluza-type reduction on U(1) followed by a Pauli-type coset reduction on S^2. More generally, we show that any D-dimensional theory that itself arises as a Kaluza U(1) reduction from (D+1) dimensions admits a consistent Pauli reduction on any coset of the form G/U(1). Extensions to the case G/H are given. Pauli coset reductions of the bosonic string on G= (G\times G)/G are believed to be consistent, and a consistency proof exists for S^3=SO(4)/SO(3). We examine these reductions, and arguments for consistency, in detail. The structures of the theories obtained instead by DeWitt-type group-manifold reductions of the bosonic string are also studied, allowing us to make contact with previous such work in which only singlet scalars are retained. Consistent truncations with two singlet scalars are possible. Intriguingly, despite the fact that these are not supersymmetric models, if the group manifold has dimension 3 or 25 they admit a superpotential formulation, and hence first-order equations yielding domain-wall solutions.Comment: Latex, 5 figures, 45 pages, minor correction

Gonococcal Acute Septic Arthritis in Immunocompetent Patients

The objective of this study is to estimate the clinical evolution and the biological values and of three cases suffering from Gonococcal acute septic arthritis (GASA).Our study is based in a thoroughfully screening of 18 patients hospitalized in our service during the period of time of March 2011 – July 2016. Among those 18 cases, 12 of them (66.7%) were diagnosed with Acute Septic Arthritis (ASA) due to Staphylococcus aureus, 3 cases (16.65%) were diagnosed with ASA due to Neisseria gonorrhoeae, and 3 other cases (16.65%) were diagnosed with ASA due to Streptococcus pneumoniae, Escherichia coli and Echinella corrodens. Two sexually active women at the seventh and tenth day of an untreated suppurative cervico-vaginitis and one man at the eighth day of an untreated suppurative urethritis were consulted at the Service of Infectious Diseases of University Hospital Center “Mother Theresa”, because of: severe pains in left wrist, in the left elbow and in the right knee, swollen of those articulation, difficulties in their movements, shivering and a high fever of   38-39.2ºC. Neisseria gonorrhea was insolated in three cases in blood cultures and cervical/urethral samples and they were sensitive towards Cyclines, Cephalosporins and Fluoroquinolones. All three patients were immunocompetent. Keywords: Neisseria gonorrhea, Acute Septic Arthritis, Biological values

On the Nonlinear Stability of Asymptotically Anti-de Sitter Solutions

Despite the recent evidence that anti-de Sitter spacetime is nonlinearly unstable, we argue that many asymptotically anti-de Sitter solutions are nonlinearly stable. This includes geons, boson stars, and black holes. As part of our argument, we calculate the frequencies of long-lived gravitational quasinormal modes of AdS black holes in various dimensions. We also discuss a new class of asymptotically anti-de Sitter solutions describing noncoalescing black hole binaries.Comment: 26 pages. 5 figure