On Time-sensitive Control Dependencies

We present efficient algorithms for time-sensitive control dependencies (CDs). If statement y is time-sensitively control dependent on statement x, then x decides not only whether y is executed but also how many timesteps after x. If y is not standard control dependent on x, but time-sensitively control dependent, then y will always be executed after x, but the execution time between x and y varies. This allows us to discover, e.g., timing leaks in security-critical software. We systematically develop properties and algorithms for time-sensitive CDs, as well as for nontermination-sensitive CDs. These work not only for standard control flow graphs (CFGs) but also for CFGs lacking a unique exit node (e.g., reactive systems). We show that Cytron’s efficient algorithm for dominance frontiers [10] can be generalized to allow efficient computation not just of classical CDs but also of time-sensitive and nontermination-sensitive CDs. We then use time-sensitive CDs and time-sensitive slicing to discover cache timing leaks in an AES implementation. Performance measurements demonstrate scalability of the approach

Rekonfigurierbare Lithium-Ionen-Batterien für den Betrieb von industriellen Produktionsstätten

Lithium-Ionen-Batteriespeicher spielen eine zunehmend wichtige Rolle bei der Integration erneuerbarer Energien in das Stromnetz. Mit dem in dieser Arbeit entwickelten rekonfigurierbaren Batteriesystem, basierend auf kaskadierten DC/DC-Wandlern, kann die Leistung auf Modulebene geregelt werden. Die zusätzlichen Freiheitsgrade steigern die verfügbare Kapazität und die Lebensdauer der Batterie. Zudem können defekte Module zur Erhöhung der Verfügbarkeit überbrückt werden. Ferner werden in dieser Arbeit Auslegungsmethoden von industriellen Batteriespeichern und Modelle zur Lebensdauersimulation der entwickelten rekonfigurierbaren Batteriesysteme vorgestellt

Combining Graph-Based and Deduction-Based Information-Flow Analysis

Information flow control (IFC) is a category of techniques for ensuring system security by enforcing information flow properties such as non-interference. Established IFC techniques range from fully automatic approaches with much over-approximation to approaches with high pre- cision but potentially laborious user interaction. A noteworthy approach mitigating the weaknesses of both automatic and interactive IFC tech- niques is the hybrid approach, developed by Küsters et al., which – how- ever – is based on program modifications and still requires a significant amount of user interaction. In this paper, we present a combined approach that works without any program modifications. It minimizes potential user interactions by apply- ing a dependency-graph-based information-flow analysis first. Based on over-approximations, this step potentially generates false positives. Pre- cise non-interference proofs are achieved by applying a deductive theorem prover with a specialized information-flow calculus for checking that no path from a secret input to a public output exists. Both tools are fully integrated into a combined approach, which is evaluated on a case study, demonstrating the feasibility of automatic and precise non-interference proofs for complex programs

Cost-Effectiveness of Newborn Screening for Spinal Muscular Atrophy in The Netherlands

Objectives: Spinal muscular atrophy (SMA) is a rare genetic disorder that causes progressive muscle weakness and paralysis. In its most common and severe form, the majority of untreated infants die before 2 years of age. Early detection and treatment, ideally before symptom onset, maximize survival and achievement of age-appropriate motor milestones, with potentially substantial impact on health-related quality of life. Therefore, SMA is an ideal candidate for inclusion in newborn screening (NBS) programs. We evaluated the cost-effectiveness of including SMA in the NBS program in The Netherlands. Methods: We developed a cost-utility model to estimate lifetime health effects and costs of NBS for SMA and subsequent treatment versus a treatment pathway without NBS (ie, diagnosis and treatment after presentation with overt symptoms). Model inputs were based on literature, local data, and expert opinion. Sensitivity and scenario analyses were conducted to assess model robustness and validity of results. Results: After detection of SMA by NBS in 17 patients, the number of quality-adjusted life-years gained per annual birth cohort was estimated at 320 with NBS followed by treatment compared with treatment after clinical SMA diagnosis. Total healthcare costs, including screening, diagnostics, treatment, and other healthcare resource use, were estimated to be €12 014 949 lower for patients identified by NBS. Conclusions: NBS for early identification and treatment of SMA versus later symptomatic treatment after clinical diagnosis improves health outcomes and is less costly and, therefore, is a cost-effective use of resources. Results were robust in sensitivity and scenario analyses

Die Bedeutung der Kostenstruktur für die Effektivität von Staatshilfen

For many firms, the coronavirus crisis has lead to persistent sales slumps that generated urgent liquidity demand — unless fixed costs were reduced. The authors use a newly developed classification procedure that makes the cost structure of companies and, thus, their sensitivity to sales shocks visible. This is useful for designing effective relief measures that preserve corporate structures by protecting employment and avoiding insolvencies of companies with healthy prospects for a recovery during the post-crisis period. Such an approach helps to accelerate economic recovery

Kriegsauswirkungen auf Unternehmen: Energieabhängigkeit und Preiserhöhungen

The results of a continuous firm survey (conducted by the German Business Panel) are presented to shed light on the economic implications of the Russian invasion in Ukraine for German firms. The current developments impact the economic outlook and lead firms to invest and hire less. More than half of all surveyed firms report that gas rationing would affect their production either directly or indirectly through their supply chain. Furthermore, one-half of firms report that it would require less than one year to adjust to a hypothetical situation in which it has 50 % less gas. However, more than a quarter of firms indicate an adjustment period that is longer than two years. Price increases are a direct response to cost pressure that is caused by the development of energy prices and supply-chain disruptions

Kostenflexibilität und Krisenreaktionen von Unternehmen in Deutschland : German Business Panel: Unternehmen in der Coronal-Krise

Die Sorge ist berechtigt, dass Unternehmen mit hohem Kostendruck während der Krise durch drastische, die Substanz angreifende Sparmaßnahmen ihre zukünftige Wettbewerbsfähigkeit verlieren. So zeigen unsere Daten, dass Betriebe mit geringer Kostenflexibilität trotz der staatlichen Hilfsmaßnahmen häufiger um ihre Existenz bangen und zukünftig weniger investieren wollen. Unterstützungsmaßnahmen sollten demnach die Kostenstrukturen der Betriebe noch direkter berücksichtigen, um gerecht und effektiv zu wirken

Interval Slopes as Numerical Abstract Domain for Floating-Point Variables

The design of embedded control systems is mainly done with model-based tools such as Matlab/Simulink. Numerical simulation is the central technique of development and verification of such tools. Floating-point arithmetic, that is well-known to only provide approximated results, is omnipresent in this activity. In order to validate the behaviors of numerical simulations using abstract interpretation-based static analysis, we present, theoretically and with experiments, a new partially relational abstract domain dedicated to floating-point variables. It comes from interval expansion of non-linear functions using slopes and it is able to mimic all the behaviors of the floating-point arithmetic. Hence it is adapted to prove the absence of run-time errors or to analyze the numerical precision of embedded control systems

Increase of [18F]FLT Tumor Uptake In Vivo Mediated by FdUrd: Toward Improving Cell Proliferation Positron Emission Tomography

Purpose: 3′-deoxy-3′-[18F]fluorothymidine ([18F]FLT), a cell proliferation positron emission tomography (PET) tracer, has been shown in numerous tumors to be more specific than 2-deoxy-2-[18F]fluoro-d-glucose ([18F]FDG) but less sensitive. We studied the capacity of a nontoxic concentration of 5-fluoro-2′-deoxyuridine (FdUrd), a thymidine synthesis inhibitor, to increase uptake of [18F]FLT in tumor xenografts. Methods: The duration of the FdUrd effect in vivo on tumor cell cycling and thymidine analogue uptake was studied by varying FdUrd pretreatment timing and holding constant the timing of subsequent flow cytometry and 5-[125I]iodo-2′-deoxyuridine biodistribution measurements. In [18F]FLT studies, FdUrd pretreatment was generally performed 1h before radiotracer injection. [18F]FLT biodistributions were measured 1 to 3h after radiotracer injection of mice grafted with five different human tumors and pretreated or not with FdUrd and compared with [18F]FDG tumor uptake. Using microPET, the dynamic distribution of [18F]FLT was followed for 1.5h in FdUrd pretreated mice. High-field T2-weighted magnetic resonance imaging (MRI) and histology were used comparatively in assessing tumor viability and proliferation. Results: FdUrd induced an immediate increase in tumor uptake of 5-[125I]iodo-2′-deoxyuridine, that vanished after 6h, as also confirmed by flow cytometry. Biodistribution measurements showed that FdUrd pretreatment increased [18F]FLT uptake in all tumors by factors of 3.2 to 7.8 compared with controls, while [18F]FDG tumor uptake was about fourfold and sixfold lower in breast cancers and lymphoma. Dynamic PET in FdUrd pretreated mice showed that [18F]FLT uptake in all tumors increased steadily up to 1.5h. MRI showed a well-vascularized homogenous lymphoma with high [18F]FLT uptake, while in breast cancer, a central necrosis shown by MRI was inactive in PET, consistent with the histomorphological analysis. Conclusion: We showed a reliable and significant uptake increase of [18F]FLT in different tumor xenografts after low-dose FdUrd pretreatment. These results show promise for a clinical application of FdUrd aimed at increasing the sensitivity of [18F]FLT PE