Weighted Modal Transition Systems

Specification theories as a tool in model-driven development processes of component-based software systems have recently attracted a considerable attention. Current specification theories are however qualitative in nature, and therefore fragile in the sense that the inevitable approximation of systems by models, combined with the fundamental unpredictability of hardware platforms, makes it difficult to transfer conclusions about the behavior, based on models, to the actual system. Hence this approach is arguably unsuited for modern software systems. We propose here the first specification theory which allows to capture quantitative aspects during the refinement and implementation process, thus leveraging the problems of the qualitative setting. Our proposed quantitative specification framework uses weighted modal transition systems as a formal model of specifications. These are labeled transition systems with the additional feature that they can model optional behavior which may or may not be implemented by the system. Satisfaction and refinement is lifted from the well-known qualitative to our quantitative setting, by introducing a notion of distances between weighted modal transition systems. We show that quantitative versions of parallel composition as well as quotient (the dual to parallel composition) inherit the properties from the Boolean setting.Comment: Submitted to Formal Methods in System Desig

Synchronizing Words for Weighted and Timed Automata

The problem of synchronizing automata is concerned with the existence of a word that sends all states of the automaton to one and the same state. This problem has classically been studied for complete deterministic finite automata, with the existence problem being NLOGSPACE-complete. In this paper we consider synchronizing-word problems for weighted and timed automata. We consider the synchronization problem in several variants and combinations of these, including deterministic and non-deterministic timed and weighted automata, synchronization to unique location with possibly different clock valuations or accumulated weights, as well as synchronization with a safety condition forbidding the automaton to visit states outside a safety-set during synchronization (e.g. energy constraints). For deterministic weighted automata, the synchronization problem is proven PSPACE-complete under energy constraints, and in 3-EXPSPACE under general safety constraints. For timed automata the synchronization problems are shown to be PSPACE-complete in the deterministic case, and undecidable in the non-deterministic case

Med fare for at blive tabt mellem to stole: Forsvarsattachéerne som en integreret del af udetjenesten

Udenrigsministeriet har ikke længere monopol på dansk udenrigspolitik. Derimod ser vi et sektordiplomati i stigende vækst, hvor især forsvarsattachéembedet er højaktuelt i en tid, hvor de tektoniske plader i udenrigspolitikken flytter sig. Vi undersøger det ellers uudforskede danske forsvarsattachéembede. Dette gøres med et særlig fokus på de komplekse samarbejdsrelationer, der er vilkåret for forsvarsattachéen både ude på ambassaderne, men også i relationerne til Forsvarsministeriet, Forsvarskommandoen og Udenrigsministeriet. På trods af forskellige professioner og kulturforståelser fungerer samarbejdet i de fleste tilfælde godt. Som det oftest er i processer med mange forskelligartede aktører, kan der dog opstå misforståelser og videnstab. I en tid, hvor Danmark som småstat forsøger at bibeholde internationalt samarbejde og de diplomatiske dyder, er det vigtigt at tage pulsen på forsvarsattachévirket, så det kan indrettes således, at det bedst muligt kan være med til at fremme danske interesser

Comparison of vaccine-induced antibody neutralization against SARS-CoV-2 variants of concern following primary and booster doses of COVID-19 vaccines

The SARS-CoV-2 pandemic has, as of July 2022, infected more than 550 million people and caused over 6 million deaths across the world. COVID-19 vaccines were quickly developed to protect against severe disease, hospitalization and death. In the present study, we performed a direct comparative analysis of four COVID-19 vaccines: BNT162b2 (Pfizer/BioNTech), mRNA-1273 (Moderna), ChAdOx1 (Oxford/AstraZeneca) and Ad26.COV2.S (Johnson & Johnson/Janssen), following primary and booster vaccination. We focused on the vaccine-induced antibody-mediated immune response against multiple SARS-CoV-2 variants: wildtype, B.1.1.7 (Alpha), B.1.351 (Beta), B.1.617.2 (Delta) and B.1.1.529 (Omicron). The analysis included the quantification of total IgG levels against SARS-CoV-2 Spike, as well as the quantification of antibody neutralization titers. Furthermore, the study assessed the high-throughput ACE2 competition assay as a surrogate for the traditional pseudovirus neutralization assay. The results demonstrated marked differences in antibody-mediated immune responses. The lowest Spike-specific IgG levels and antibody neutralization titers were induced by one dose of the Ad26.COV2.S vaccine, intermediate levels by two doses of the BNT162b2 vaccine, and the highest levels by two doses of the mRNA-1273 vaccine or heterologous vaccination of one dose of the ChAdOx1 vaccine and a subsequent mRNA vaccine. The study also demonstrated that accumulation of SARS-CoV-2 Spike protein mutations was accompanied by a marked decline in antibody neutralization capacity, especially for B.1.1.529. Administration of a booster dose was shown to significantly increase Spike-specific IgG levels and antibody neutralization titers, erasing the differences between the vaccine-induced antibody-mediated immune response between the four vaccines. The findings of this study highlight the importance of booster vaccines and the potential inclusion of future heterologous vaccination strategies for broad protection against current and emerging SARS-CoV-2 variants

Effect of the Carer Support Needs Assessment Tool intervention (CSNAT-I) in the Danish specialised palliative care setting: a stepped-wedge cluster randomised controlled trial

Background: The Carer Support Needs Assessment Tool intervention (CSNAT-I) has been shown to improve end-of-life care support for informal caregivers. This study investigated the impact of the CSNAT-I on caregivers of patients recently enrolled in specialised palliative care (SPC) at home in Denmark. Methods: A stepped-wedge cluster randomised controlled trial with nine clusters (ie, SPC teams). Outcome measures were collected using caregiver questionnaires at baseline (T0) and 2-week (T1) and 4-week (T2) follow-up. Results: A total of 437 caregivers were enrolled (control group, n=255; intervention group, n=182). No intervention effect was found on the primary outcome, caregiver strain at T1 (p=0.1865). However, positive effects were found at T1 and T2 on attention to caregivers’ well-being (p<0.0001), quality of information and communication (p<0.0001), amount of information (T1: p=0.0002; T2: p<0.0001), involvement (T1: p=0.0045; T2: p<0.0001), talking about greatest burdens (p<0.0001) and assistance in managing greatest burdens (p<0.0001). The effect sizes of these differences were medium or large and seemed to increase from T1 to T2. At T1, positive effects were found on distress (p=0.0178) and home care responsibility (p=0.0024). No effect was found on the remaining outcomes. Conclusion: Although no effect was found on caregiver strain, the CSNAT-I showed positive effects on caregiver distress, home care responsibility and key outcomes regarding caregivers’ experience of the interaction with healthcare professionals. Trial registration number: NCT03466580