bluuebunny/crossref_metadata_2025_split huggingface dataset:
Runtime Enforcement of Security Policies on Black Box Reactive Programs
Authors: Ngo Minh , Massacci Fabio , Milushev Dimiter , Piessens Frank 
Published: May 2015

Security enforcement mechanisms like execution monitors are used to make sure that some untrusted program complies with a policy. Different enforcement mechanisms have different strengths and weaknesses and hence it is important to understand the qualities of various enforcement mechanisms.

This paper studies runtime enforcement mechanisms for reactive programs. We study the impact of two important constraints that many practical enforcement mechanisms satisfy: (1) the enforcement mechanism must handle each input/output event in finite time and on occurrence of the event (as opposed to for instance Ligatti's edit automata that have the power to buffer events for an arbitrary amount of time), and (2) the enforcement mechanism treats the untrusted program as a
black box
: it can monitor and/or edit the input/output events that the program exhibits on execution and it can explore alternative executions of the program by running additional copies of the program and providing these different inputs. It can
not
inspect the source or machine code of the untrusted program.

Such enforcement mechanisms are important in practice: they include for instance many execution monitors, virtual machine monitors, and secure multi-execution or shadow executions.
We establish upper and lower bounds for the class of policies that are enforceable by such black box mechanisms, and we propose a generic enforcement mechanism that works for a wide range of policies. We also show how our generic enforcement mechanism can be instantiated to enforce specific classes of policies, at the same time showing that many existing enforcement mechanisms are optimized instances of our construction.
Full Abstraction for Signal Flow Graphs
Authors: Bonchi Filippo , Sobocinski Pawel , Zanasi Fabio 
Published: May 2015

Network theory uses the string diagrammatic language of monoidal categories to study graphical structures formally, eschewing specialised translations into intermediate formalisms. Recently, there has been a concerted research focus on developing a network theoretic approach to signal flow graphs, which are classical structures in control theory, signal processing and a cornerstone in the study of feedback. In this approach, signal flow graphs are given a relational denotational semantics in terms of formal power series.
Thus far, the operational behaviour of such signal flow graphs has only been discussed at an intuitive level. In this paper we equip them with a structural operational semantics. As is typically the case, the purely operational picture is too concrete -- two graphs that are denotationally equal may exhibit different operational behaviour. We classify the ways in which this can occur and show that any graph can be realised -- rewritten, using the graphical theory, into an executable form where the operational behavior and the denotation coincides.
Succinct Representation of Concurrent Trace Sets
Authors: Gupta Ashutosh , Henzinger Thomas A. , Radhakrishna Arjun , Samanta Roopsha , Tarrach Thorsten 
Published: May 2015

We present a method and a tool for generating succinct representations of sets of concurrent traces. We focus on trace sets that contain all correct or all incorrect permutations of events from a given trace. We represent trace sets as HB-Formulas that are Boolean combinations of happens-before constraints between events. To generate a representation of incorrect interleavings, our method iteratively explores interleavings that violate the specification and gathers generalizations of the discovered interleavings into an HB-Formula; its complement yields a representation of correct interleavings.
We claim that our trace set representations can drive diverse verification, fault localization, repair, and synthesis techniques for concurrent programs. We demonstrate this by using our tool in three case studies involving synchronization synthesis, bug summarization, and abstraction refinement based verification. In each case study, our initial experimental results have been promising.
In the first case study, we present an algorithm for inferring missing synchronization from an HB-Formula representing correct interleavings of a given trace. The algorithm applies rules to rewrite specific patterns in the HB-Formula into locks, barriers, and wait-notify constructs. In the second case study, we use an HB-Formula representing incorrect interleavings for bug summarization. While the HB-Formula itself is a concise counterexample summary, we present additional inference rules to help identify specific concurrency bugs such as data races, define-use order violations, and two-stage access bugs. In the final case study, we present a novel predicate learning procedure that uses HB-Formulas representing abstract counterexamples to accelerate counterexample-guided abstraction refinement (CEGAR). In each iteration of the CEGAR loop, the procedure refines the abstraction to eliminate multiple spurious abstract counterexamples drawn from the HB-Formula.
A Coalgebraic Decision Procedure for NetKAT
Authors: Foster Nate , Kozen Dexter , Milano Mae , Silva Alexandra , Thompson Laure 
Published: May 2015

NetKAT is a domain-specific language and logic for specifying and verifying network packet-processing functions. It consists of Kleene algebra with tests (KAT) augmented with primitives for testing and modifying packet headers and encoding network topologies. Previous work developed the design of the language and its standard semantics, proved the soundness and completeness of the logic, defined a PSPACE algorithm for deciding equivalence, and presented several practical applications.
This paper develops the coalgebraic theory of NetKAT, including a specialized version of the Brzozowski derivative, and presents a new efficient algorithm for deciding the equational theory using bisimulation. The coalgebraic structure admits an efficient sparse representation that results in a significant reduction in the size of the state space. We discuss the details of our implementation and optimizations that exploit NetKAT's equational axioms and coalgebraic structure to yield significantly improved performance. We present results from experiments demonstrating that our tool is competitive with state-of-the-art tools on several benchmarks including all-pairs connectivity, loop-freedom, and translation validation.
Data-Parallel String-Manipulating Programs
Authors: Veanes Margus , Mytkowicz Todd , Molnar David , Livshits Benjamin 
Published: May 2015

String-manipulating programs are an important class of programs with applications in malware detection, graphics, input sanitization for Web security, and large-scale HTML processing. This paper extends prior work on BEK, an expressive domain-specific language for writing string-manipulating programs, with algorithmic insights that make BEK both analyzable and data-parallel. By analyzable we mean that unlike most general purpose programming languages, many algebraic properties of a BEK program are decidable (i.e., one can check whether two programs commute or compute the inverse of a program). By data-parallel we mean that a BEK program can compute on arbitrary subsections of its input in parallel, thus exploiting parallel hardware. This latter requirement is particularly important for programs which operate on large data: without data parallelism, a programmer cannot hide the latency of reading data from various storage media (i.e., reading a terabyte of data from a modern hard drive takes about 3 hours). With a data-parallel approach, the system can split data across multiple disks and thus hide the latency of reading the data.
A BEK program is expressive: a programmer can use conditionals, switch statements, and registers--or local variables--in order to implement common string-manipulating programs. Unfortunately, this expressivity induces data dependencies, which are an obstacle to parallelism. The key contribution of this paper is an algorithm which automatically removes these data dependencies by mapping a B EK program into a intermediate format consisting of symbolic transducers, which extend classical transducers with symbolic predicates and symbolic assignments. We present a novel algorithm that we call exploration which performs symbolic loop unrolling of these transducers to obtain simplified versions of the original program. We show how these simplified versions can then be lifted to a stateless form, and from there compiled to data-parallel hardware.
To evaluate the efficacy of our approach, we demonstrate up to 8x speedups for a number of real-world, BEK programs, (e.g., HTML encoder and decoder) on data-parallel hardware. To the best of our knowledge, these are the first data parallel implementation of these programs. To validate that our approach is correct, we use an automatic testing technique to compare our generated code to the original implementations and find no semantic deviations.
APO866 Increases Antitumor Activity of Cyclosporin-A by Inducing Mitochondrial and Endoplasmic Reticulum Stress in Leukemia Cells
Authors: Cagnetta Antonia , Caffa Irene , Acharya Chirag , Soncini Debora , Acharya Prakrati , Adamia Sophia , Pierri Ivana , Bergamaschi Micaela , Garuti Anna , Fraternali Giulio , Mastracci Luca , Provenzani Alessandro , Zucal Chiara , Damonte Gianluca , Salis Annalisa , Montecucco Fabrizio , Patrone Franco , Ballestrero Alberto , Bruzzone Santina , Gobbi Marco , Nencioni Alessio , Cea Michele 
Published: May 2015

Abstract
Purpose: The nicotinamide phosphoribosyltransferase (NAMPT) inhibitor, APO866, has been previously shown to have antileukemic activity in preclinical models, but its cytotoxicity in primary leukemia cells is frequently limited. The success of current antileukemic treatments is reduced by the occurrence of multidrug resistance, which, in turn, is mediated by membrane transport proteins, such as P-glycoprotein-1 (Pgp). Here, we evaluated the antileukemic effects of APO866 in combination with Pgp inhibitors and studied the mechanisms underlying the interaction between these two types of agents.
Experimental Design: The effects of APO866 with or without Pgp inhibitors were tested on the viability of leukemia cell lines, primary leukemia cells (AML, n = 6; B-CLL, n = 19), and healthy leukocytes. Intracellular nicotinamide adenine dinucleotide (NAD+) and ATP levels, mitochondrial transmembrane potential (ΔΨm), markers of apoptosis and of endoplasmic reticulum (ER) stress were evaluated.
Results: The combination of APO866 with Pgp inhibitors resulted in a synergistic cytotoxic effect in leukemia cells, while sparing normal CD34+ progenitor cells and peripheral blood mononuclear cells. Combining Pgp inhibitors with APO866 led to increased intracellular APO866 levels, compounded NAD+ and ATP shortage, and induced ΔΨm dissipation. Notably, APO866, Pgp inhibitors and, to a much higher extent, their combination induced ER stress and ER stress inhibition strongly reduced the activity of these treatments.
Conclusions: APO866 and Pgp inhibitors show a strong synergistic cooperation in leukemia cells, including acute myelogenous leukemia (AML) and B-cell chronic lymphocytic leukemia (B-CLL) samples. Further evaluations of the combination of these agents in clinical setting should be considered. Clin Cancer Res; 21(17); 3934–45. ©2015 AACR.
Cosilencing of PKM-2 and MDR-1 Sensitizes Multidrug-Resistant Ovarian Cancer Cells to Paclitaxel in a Murine Model of Ovarian Cancer
Authors: Talekar Meghna , Ouyang Qijun , Goldberg Michael S. , Amiji Mansoor M. 
Published: May 2015

Abstract
Tumor multidrug resistance (MDR) is a serious clinical challenge that significantly limits the effectiveness of cytotoxic chemotherapy. As such, complementary therapeutic strategies are being explored to prevent relapse. The altered metabolic state of cancer cells, which perform aerobic glycolysis, represents an interesting target that can enable discrimination between healthy cells and cancer cells. We hypothesized that cosilencing of genes responsible for aerobic glycolysis and for MDR would have synergistic antitumor effect. In this study, siRNA duplexes against pyruvate kinase M2 and multidrug resistance gene-1 were encapsulated in hyaluronic acid–based self-assembling nanoparticles. The particles were characterized for morphology, size, charge, encapsulation efficiency, and transfection efficiency. In vivo studies included biodistribution assessment, gene knockdown confirmation, therapeutic efficacy, and safety analysis. The benefit of active targeting of cancer cells was confirmed by modifying the particles' surface with a peptide targeted to epidermal growth factor receptor, which is overexpressed on the membranes of the SKOV-3 cancer cells. To augment the studies involving transplantation of a paclitaxel-resistant cell line, an in vivo paclitaxel resistance model was developed by injecting repeated doses of paclitaxel following tumor inoculation. The nanoparticles accumulated significantly in the tumors, hindering tumor volume doubling time (P &lt; 0.05) upon combination therapy in both the wild-type (2-fold) and resistant (8-fold) xenograft models. Although previous studies indicated that silencing of MDR-1 alone sensitized MDR ovarian cancer to paclitaxel only modestly, these data suggest that concurrent silencing of PKM-2 improves the efficacy of paclitaxel against MDR ovarian cancer. Mol Cancer Ther; 14(7); 1521–31. ©2015 AACR.
Epicardial Phrenic Nerve Displacement During Catheter Ablation of Atrial and Ventricular Arrhythmias
Authors: Kumar Saurabh , Barbhaiya Chirag R. , Baldinger Samuel H. , Koplan Bruce A. , Maytin Melanie , Epstein Laurence M. , John Roy M. , Michaud Gregory F. , Tedrow Usha B. , Stevenson William G. 
Published: May 2015

Background—
Arrhythmia origin in close proximity to the phrenic nerve (PN) can hinder successful catheter ablation. We describe our approach with epicardial PN displacement in such instances.

Methods and Results—
PN displacement via percutaneous pericardial access was attempted in 13 patients (age 49±16 years, 9 females) with either atrial tachycardia (6 patients) or atrial fibrillation triggered from a superior vena cava focus (1 patient) adjacent to the right PN or epicardial ventricular tachycardia origin adjacent to the left PN (6 patients). An epicardially placed steerable sheath/4 mm-catheter combination (5 patients) or a vascular or an esophageal balloon (8 patients) was ultimately successful. Balloon placement was often difficult requiring manipulation via a steerable sheath. In 2 ventricular tachycardia cases, absence of PN capture was achieved only once the balloon was directly over the ablation catheter. In 3 atrial tachycardia patients, PN displacement was not possible with a balloon; however, a steerable sheath/catheter combination was ultimately successful. PN displacement allowed acute abolishment of all targeted arrhythmias. No PN injury occurred acutely or in follow up. Two patients developed acute complications (pleuro-pericardial fistula 1 and pericardial bleeding 1). Survival free of target arrhythmia was achieved in all atrial tachycardia patients; however, a nontargeted ventricular tachycardia recurred in 1 patient at a median of 13 months’ follow up.

Conclusions—
Arrhythmias originating in close proximity to the PN can be targeted successfully with PN displacement with an epicardially placed steerable sheath/catheter combination, or balloon, but this strategy can be difficult to implement. Better tools for phrenic nerve protection are desirable.
The Sensitivity of Salt Wedge Estuaries to Channel Geometry
Authors: Poggioli Anthony R. , Horner-Devine Alexander R. 
Published: May 2015

AbstractThe authors develop a two-layer hydraulic model to determine the saline intrusion length in sloped and converging salt wedge estuaries. They find that the nondimensional intrusion length = CiL/hS depends significantly on the channel bottom slope and the rate and magnitude of landward width convergence, in addition to the freshwater Froude number. In the definition of , Ci is a quadratic interfacial drag coefficient, L is the salt wedge intrusion length, and hS is the depth at the mouth of the estuary. Bottom slope is found to limit the saline intrusion length, and this limitation accounts for the deviation of the observed exponent n in a scaling relationship with the river discharge of the form L ~ Q−n from the canonical value of 2 to 2.5 predicted by the theory of Schijf and Schönfeld for a flat, prismatic estuary. The authors find that estuary convergence is important only when the ratio of the slope-limited intrusion length to the convergence length is greater than one, and that the effects of convergence are less significant than those of slope limitation. They compare this model to field and validated numerical data and find that the solution predicts the intrusion length with good accuracy, improving on the flat, prismatic solution by orders of magnitude. While this model has good predictive capability, it is sensitive to Ci and the location of the hydraulic control point, both difficult to determine a priori.
Near-Surface Density Currents Observed in the Southeast Pacific Stratocumulus-Topped Marine Boundary Layer*
Authors: Wilbanks Matt C. , Yuter Sandra E. , de Szoeke Simon P. , Brewer W. Alan , Miller Matthew A. , Hall Andrew M. , Burleyson Casey D. 
Published: May 2015

Abstract
Density currents (i.e., cold pools or outflows) beneath marine stratocumulus clouds are characterized using 30 days of ship-based observations obtained during the 2008 Variability of American Monsoon Systems (VAMOS) Ocean–Cloud–Atmosphere–Land Study Regional Experiment (VOCALS-REx) in the southeast Pacific. An air density increase criterion applied to the Improved Meteorological (IMET) sensor data identified 71 density current front, core (peak density), and tail (dissipating) zones. The similarity in speeds of the mean density current propagation speed (1.8 m s−1) and the mean cloud-level advection relative to the surface layer wind (1.9 m s−1) allowed drizzle cells to deposit elongated density currents in their wakes. Scanning Doppler lidar captured prefrontal updrafts with a mean intensity of 0.91 m s−1 and an average vertical extent of 800 m. Updrafts were often surmounted by low-lying shelf clouds not connected to the overlying stratocumulus cloud. The observed density currents were 5–10 times thinner and weaker than typical continental thunderstorm cold pools. Nearly 90% of density currents were identified when C-band radar estimated areal average rain rates exceeded 1 mm day−1 over a 30-km diameter. Rather than peaking when rain rates were highest overnight, density current occurrence peaks between 0600 and 0800 local solar time when enhanced local drizzle co-occurred with shallow subcloud dry and stable layers. The dry layers may have contributed to density current formation by enhancing subcloud evaporation of drizzle. Density currents preferentially occurred in a large region of predominantly open cells but also occurred in regions of closed cells.
Boredom proneness predicts quality of life in outpatients diagnosed with schizophrenia-spectrum disorders
Authors: Gerritsen Cory J , Goldberg Joel O , Eastwood John D 
Published: May 2015

Background: There is increasing recognition of the clinical significance of boredom associated with functional impairments in schizophrenia. Previous work has highlighted the importance of motivational deficits more broadly, although no study has yet explored the unique effects of boredom on community outcomes. Aims: This study aims to measure boredom proneness among outpatients diagnosed with schizophrenia to determine whether it is elevated in this population and to determine its relation to quality-of-life outcomes. Methods: A self-report measure of boredom proneness along with standard measures of symptoms and functional status was administered to a community-dwelling sample of schizophrenia outpatients. Results: Boredom proneness was found to be elevated in this population and was associated with reduced quality of life, specifically with leisure activity dissatisfaction and reduced sense of financial well-being. Negative symptoms were determined to be associated with reduced work and school functioning. Conclusion: This pattern of unique effects on quality of life highlights the clinical relevance of identifying a subjective state of boredom and has theoretical importance in distinguishing boredom proneness specifically from more general avolitional and amotivational conditions that have tended to be the focus of clinical observation and previous research.
Vagally mediated heart rate variability in headache patients—a systematic review and meta-analysis
Authors: Koenig Julian , Williams DeWayne P , Kemp Andrew H , Thayer Julian F 
Published: May 2015

Objective Vagal nerve activity—indexed by heart rate variability (HRV)—has been linked to altered pain processing and inflammation, both of which may underpin headache disorders and lead to cardiovascular disease (CVD). Here we examined the evidence for differences in parasympathetic (vagal) activity indexed by time- and frequency-domain measures of HRV in patients with headache disorders compared to healthy controls (HCs). Methods A systematic review and meta-analysis was conducted on studies investigating group differences in vagally mediated HRV (vmHRV) including time- (root-mean-square of successive R-R-interval differences (RMSSD)) and frequency- (high-frequency HRV) domain measures. Studies eligible for inclusion were identified by a systematic search of the literature, based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Results Seven studies reporting a total of 10 comparisons of patients with headache disorders (HF-HRV n = 67, RMSSD n = 122) and HCs (HF-HRV n = 64, RMSSD n = 125) were eligible for inclusion. Random-effects meta-analysis revealed a significant main effect on RMSSD ( Z = 2.03, p = 0.04; Hedges’ g = −0.63; 95% CI (−1.24, –0.02); k = 6) and similar pooled effect size estimates for HF-HRV when breathing was controlled ( g = −0.30; 95% CI (−0.69; 0.10)) but not when breathing was not controlled ( g = 0.02; 95% CI (−0.69; 0.74)). Controlling for breathing had no effect on RMSSD. Conclusion vmHRV is reduced in patients with headache disorders, findings associated with a medium effect size. Suggestions for future research in this area are provided, emphasizing a need to investigate the impact of headache disorders and commonly comorbid conditions—including mental disorders—as well as the investigation of the risk for CVD in migraine in particular. We further emphasize the need for large-scale studies to investigate HRV as a mechanism mediating the association of migraine and CVD.