Permission-Based Separation Logic for Multithreaded Java Programs

This paper motivates and presents a program logic for reasoning about multithreaded Java-like programs with concurrency primitives such as dynamic thread creation, thread joining and reentrant object monitors. The logic is based on concurrent separation logic. It is the first detailed adaptation of concurrent separation logic to a multithreaded Java-like language. The program logic associates a unique static access permission with each heap location, ensuring exclusive write accesses and ruling out data races. Concurrent reads are supported through fractional permissions. Permissions can be transferred between threads upon thread starting, thread joining, initial monitor entrancies and final monitor exits.\ud This paper presents the basic principles to reason about thread creation and thread joining. It finishes with an outlook how this logic will evolve into a full-fledged verification technique for Java (and possibly other multithreaded languages)

Permission-Based Separation Logic for Multithreaded Java Programs

This paper presents a program logic for reasoning about multithreaded Java-like programs with dynamic thread creation, thread joining and reentrant object monitors. The logic is based on concurrent separation logic. It is the first detailed adaptation of concurrent separation logic to a multithreaded Java-like language. The program logic associates a unique static access permission with each heap location, ensuring exclusive write accesses and ruling out data races. Concurrent reads are supported through fractional permissions. Permissions can be transferred between threads upon thread starting, thread joining, initial monitor entrancies and final monitor exits. In order to distinguish between initial monitor entrancies and monitor reentrancies, auxiliary variables keep track of multisets of currently held monitors. Data abstraction and behavioral subtyping are facilitated through abstract predicates, which are also used to represent monitor invariants, preconditions for thread starting and postconditions for thread joining. Value-parametrized types allow to conveniently capture common strong global invariants, like static object ownership relations. The program logic is presented for a model language with Java-like classes and interfaces, the soundness of the program logic is proven, and a number of illustrative examples are presented

Real option analysis in a replicating portfolio perspective

In the last decades, a vast body of literature has arisen on real option analysis (ROA). The use of di¤erent approaches and the often implicit adoption of major assumptions may cause confusion on what ROA precisely entails, or in which situations it may be applied. We assess the �eld of real option analysis by explicitly linking ROA to the basic principles of option pricing theory and the replicating portfolio concept. From this perspective, we explain how real options adjust to the varying risk pro�les of a project, a feature not available in other valuation methods. We also clarify how non-market risks can be dealt with in ROA. We show that a combination of option pricing and decision tree analysis enables us to treat a broad range of investment problems, in a manner that is consistent with pricing theory

Principles of Contract Languages:Dagstuhl Seminar 22451

This report documents the program and the outcomes of Dagstuhl Seminar 22451 "Principles of Contract Languages". At the seminar, participants discussed the fundamental aspects of software contracts. Topics included the format and expressiveness of contracts, their use cases in software development and analysis, and contract composition and decomposition

Disentangling dyadic and reputational perceptions of prosociality, aggression, and popularity in explaining friendship networks in early adolescence

This study examined the differential effects of two forms of adolescents' perceptions of peers' prosociality, aggression, and popularity, on friendship selection. Individuals' reports of their peers' behaviors (dyadic perceptions) and the aggregated classmates' reports (reputational perceptions) were disentangled. The findings indicated that adolescents were more likely to befriend classmates widely perceived as prosocial (reputational perception) and were less likely to befriend classmates they perceived as aggressive (dyadic perception). For popularity, the effect of dyadic perception disappeared when including the reputational perception. The findings highlight the differences between the dyadic and reputational perceptions of peer behavior. Not only dyadic perceptions of behaviors but also reputational perceptions exert a role in befriending peers

Developmental nasal midline masses in children: neuroradiological evaluation

Developmental nasal midline masses in children are rare lesions. Neuroimaging is essential to characterise these lesions, to determine the exact location of the lesion and most importantly to exclude a possible intracranial extension or connection. Our objective was to evaluate CT and MRI in the diagnosis of developmental nasal midline masses. Eleven patients (mean age 4.5years) with nasal midline masses were examined by CT and MRI. Neuroimaging was evaluated for (a) lesion location/size, (b) indirect (bifid or deformed crista galli, widened foramen caecum, defect of the cribriform plate) and direct (identification of intracranially located lesion components or signal alterations) imaging signs of intracranial extension, (c) secondary complications and (d) associated malformations. Surgical and histological findings served as gold standard. Nasal dermoid sinus cysts were diagnosed in 9 patients. One patient was diagnosed with an meningocele and another patient with a nasal glioma. Indirect CT and MRI signs correlated with the surgical results in 10 of 11 patients. Direct CT findings correlated with surgery in all patients, whereas the direct MRI signs correlated in 9 of 11 patients. In 2 patients MRI showed an intracranial signal alteration not seen on CT. Neuroimaging corrected the clinical diagnosis in 1 patient. One child presented with a meningitis. In none of the patients was an associated malformation diagnosed. Intracranial extension is equally well detected by CT and MRI using indirect imaging signs. Evaluating the direct imaging signs, MRI suspected intracranial components in 2 patients without a correlate on CT. This could represent an isolated intracranial component that got undetected on CT and surgery. In 9 patients CT and MRI matched the surgical findings. The MRI did not show any false-negative results. These results in combination with the multiplanar MRI capabilities, the different image contrasts that can be generated by MRI and the lack of radiation favour the use of MRI as primary imaging tool in these young patients in which the region of imaging is usually centred on the radiosensitive eye lense

Flux-tunable Josephson Effect in a Four-Terminal Junction

We study a phase-tunable four-terminal Josephson junction formed in an InSbAs two-dimensional electron gas proximitized by aluminum. By embedding the two pairs of junction terminals in asymmetric DC SQUIDs we can control the superconducting phase difference across each pair, thereby gaining information about their current-phase relation. Using a current-bias line to locally control the magnetic flux through one SQUID, we measure a nonlocal Josephson effect, whereby the current-phase relation across two terminals in the junction is strongly dependent on the superconducting phase difference across two completely different terminals. In particular, each pair behaves as a $\phi_0$-junction with a phase offset tuned by the phase difference across the other junction terminals. Lastly, we demonstrate that the behavior of an array of two-terminal junctions replicates most features of the current-phase relation of different multiterminal junctions. This highlights that these signatures alone are not sufficient evidence of true multiterminal Josephson effects arising from hybridization of Andreev bound states in the junction.Comment: 13 pages, 8 figure

COVID-19 infectivity profile correction

The infectivity profile of an individual with COVID-19 is attributed to the paper Temporal dynamics in viral shedding and transmissibility of COVID-19 by He et al., published in Nature Medicine in April 2020. However, the analysis within this paper contains a mistake such that the published infectivity profile is incorrect and the conclusion that infectiousness begins 2.3 days before symptom onset is no longer supported. In this document we discuss the error and compute the correct infectivity profile. We also establish confidence intervals on this profile, quantify the difference between the published and the corrected profiles, and discuss an issue of normalisation when fitting serial interval data. This infectivity profile plays a central role in policy and decision making, thus it is crucial that this issue is corrected with the utmost urgency to prevent the propagation of this error into further studies and policies. We hope that this preprint will reach all researchers and policy makers who are using the incorrect infectivity profile to inform their work.Comment: 5 pages, 2 figure