Layered and object-based game semantics

Large-scale software verification relies critically on the use of compositional languages, semantic models, specifications, and verification techniques. Recent work on certified abstraction layers synthesizes game semantics, the refinement calculus, and algebraic effects to enable the composition of heterogeneous components into larger certified systems. However, in existing models of certified abstraction layers, compositionality is restricted by the lack of encapsulation of state. In this paper, we present a novel game model for certified abstraction layers where the semantics of layer interfaces and implementations are defined solely based on their observable behaviors. Our key idea is to leverage Reddy's pioneer work on modeling the semantics of imperative languages not as functions on global states but as objects with their observable behaviors. We show that a layer interface can be modeled as an object type (i.e., a layer signature) plus an object strategy. A layer implementation is then essentially a regular map, in the sense of Reddy, from an object with the underlay signature to that with the overlay signature. A layer implementation is certified when its composition with the underlay object strategy implements the overlay object strategy. We also describe an extension that allows for non-determinism in layer interfaces. After formulating layer implementations as regular maps between object spaces, we move to concurrency and design a notion of concurrent object space, where sequential traces may be identified modulo permutation of independent operations. We show how to express protected shared object concurrency, and a ticket lock implementation, in a simple model based on regular maps between concurrent object spaces.

Fundamentals of a Novel Debugging Mechanism for Orchestrated Cloud Infrastructures with Macrosteps and Active Control

In Infrastructure-as-a-Service (IaaS) clouds, the development process of a ready-to-use and reliable infrastructure might be a complex task due to the interconnected and dependent services that are deployed (and operated later on) in a concurrent way on virtual machines. Different timing conditions may change the overall initialisation method, which can lead to abnormal behaviour or failure in the non-deterministic environment. The overall motivation of our research is to improve the reliability of cloud-based infrastructures with minimal user interactions and significantly accelerate the time-consuming debugging process. This paper focuses on the behaviour of cloud-based infrastructures during their deployment phase and introduces the adaption of a replay, and active control enriched debugging technique, called macrostep, in the field of cloud orchestration in order to provide support for developers troubleshooting deployment-related errors. The fundamental macrostep mechanisms, including the generation of collective breakpoint sets as well as the traversal method for such consistent global states, have been combined with the Occopus cloud orchestrator and the Neo4J graph database. The paper describes the novel approach, the design choices as well as the implementation of the experimental debugger tool with a use case for validation purposes by providing some preliminary numerical results.

T-DSES: A Blockchain-powered Trusted Decentralized Service Eco-System

Existing Web service eco-systems are typically managed in a centralized manner, which hinders their further development due to inherent disadvantages such as trust issues, interest disputes, value separation and so on. The recently emerged blockchains provide distributed ledgers that enable parties who do not fully trust each other to maintain a set of global states, which provide a natural solution. Based on the INKchain, which is an open-source permissioned blockchain mechanism extending the Hyperledger Fabric, this paper proposes Trusted Decentralized Service Eco-System (T-DSES). T-DSES achieves not only fundamental functionalities of conventional systems, but also offers mechanisms to stimulate participants to bring trustworthiness to the whole system. The trustworthiness of T-DSES is realized by three strategies: reliable information of services and mashups, reliable records of participants’ rights, and reliable measurement of participants’ contributions. A customized token “SToken” is created to act as the media of value circulation. In this paper, the overall framework and detailed design of T-DSES are presented, especially including how to utilize Kubernetes to establish a cloud-based environment. A tailored Web front-end ensures the usability of operations. Over real-world data from ProgrammableWeb.com, analyses and experiments have been conducted to verify the feasibility and effectiveness of the presented approach.

International Telepractice for Therapy and Training: Auditory Verbal UK's Perspective

Purpose The aim of this clinical focus article is to discuss Auditory Verbal UK's (AVUK) training program for prospective listening and spoken language specialist certified auditory verbal (AV) therapists delivered globally via telepractice. Since 2015, AVUK has delivered training via telepractice to 18 countries. Consideration is given to the barriers and challenges of training across geographical and cultural boundaries, including access to technology, cultural and linguistic difference of families and trainees, and the differing global states of audiological practice for early intervention. Some possible solutions are offered. Although there have been calls for international consensus on early intervention, the reality of provision across Europe differs especially in the wake of COVID-19. From a global perspective, audiology and early intervention services differ considerably. Some countries are not up-to-date with the latest hearing technology and do not have access to tuning for cochlear implants or the technology required for families to attend therapy via telepractice. Conclusions With appropriate technology, telepractice is a viable means of providing training in AV therapy. It builds communities across geographical areas, breaking down boundaries and facilitating global collaboration. Although considerable differences remain in both service provision and access to services across different countries, the passion of trainees worldwide and the good will of the AV community in supporting our colleagues give reason for optimism going forward.

Reliably quantifying the evolving worldwide dynamic state of the COVID-19 outbreak from death records, clinical parametrization, and demographic data

The dynamic characterization of the COVID-19 outbreak is critical to implement effective actions for its control and eradication but the information available at a global scale is not sufficiently reliable to be used directly. Here, we develop a quantitative approach to reliably quantify its temporal evolution and controllability through the integration of multiple data sources, including death records, clinical parametrization of the disease, and demographic data, and we explicitly apply it to countries worldwide, covering 97.4% of the human population, and to states within the United States (US). The validation of the approach shows that it can accurately reproduce the available prevalence data and that it can precisely infer the timing of nonpharmaceutical interventions. The results of the analysis identified general patterns of recession, stabilization, and resurgence. The diversity of dynamic behaviors of the outbreak across countries is paralleled by those of states and territories in the US, converging to remarkably similar global states in both cases. Our results offer precise insights into the dynamics of the outbreak and an efficient avenue for the estimation of the prevalence rates over time.

Images of “Other Countries” in Today’s Worldview of Russian Citizens

This paper analyses the images of other countries as seen by Russian citizens. The author contemplates how the Russians perceive neighbouring countries, the strategic partners (India and China), certain European states and the European Union as a whole, as well as the United States, Turkey, and Thailand. Notwithstanding the differences in the images of these countries perceived by the Russians, they share certain similarities. First of all, those images feature some poor awareness, reflecting how ill-informed we are. The study shows that nowadays our fellow citizens know less about the world than before, and their spectrum of interests is narrower. Following the Western media, the Russian media and Internet focus on a limited number of “important” countries, ignoring the majority of the global states. Second, three decades of travel freedom influenced the worldview of millions of the Russians. Their perception of the world grew more coherent and adequate; however, it still lacks consistency and cognitive clearness. Evidently, personal experience is not sufficient to form such a vision of the global world that includes both awareness and a system of values shaped in consideration of the national interests. And third, the Russian society is not homogeneous in its perception of foreign nations. There are senior people and social groups that have largely retained idealized concepts of the world formed in the early post-Soviet period. Namely, those, who were politically socialized in late 1980s and early 1990s, as well as the intellectual elite.

Leaving Gaia behind: The ethics of space migration in Cixin Liu’s and Neal Stephenson’s science fiction

In Cixin Liu’s trilogy Remembrance of Earth’s Past (2008–2010) and Neal Stephenson’s Seveneves (2015), the surface of planet Earth becomes uninhabitable amid global states of emergency, and central governments devise radical plans to ensure the survival of the human species. In contrast to the Old Testament, where human emancipation from nature is punished, Chinese antiquity’s narratives of large-scale engineering projects are surprisingly compatible with the modern mindset which regards nature in utilitarian terms. Contemporary science fiction does not simply inherit this techno-optimistic stance, but fleshes out possible futures that are shaped by biopolitical decisions. In Stephenson’s and Liu’s prose, the proposed escape plans only benefit small segments of the population. While such procedure is incompatible with human rights, which emphasize the value of the individual over the collective, contemporary pragmatic ethics interprets such behavior as rational. Applied to more tangible scenarios, such as our increasingly depleted livelihoods on Earth, both texts document our somewhat diminished expectations regarding the future. In a world where eating human protein is “reasonable” and its rejection merely “respectable”, the preservation of humankind in space sets in motion a return to Hobbes’s “natural state of man”.

What is a global state of consciousness?

The notion of a global state (or level) of consciousness is an increasingly important construct in the science of consciousness. However, exactly what a global state of consciousness is remains poorly understood. In this paper I offer an account of global states of consciousness as consciousness-related capacity modulations. On this view global states are not themselves phenomenal states – they are not occurring experiences. Rather, they are states that specify which of a creature’s overall consciousness-related capacities are currently online. Given that the search for the neural correlates of consciousness (NCC), as it is currently conceived, is the search for the neural basis of occurrent experiences, the NCC framework is incapable of revealing the neural basis of global states. As such, a mature science of consciousness will need to move beyond the search for NCCs, as that project is currently conceived.

Partial spontaneous intersubunit rotations in actively translating ribosomes

SummaryThe ribosome is a molecular machine that adopts at least two global states during translation. Two main steps of translation, peptidyl transfer and translocation, are accompanied by counterclockwise and clockwise rotations of the two ribosomal subunits. However, when and why the ribosome alternates between these states remains unclear, with two well supported but conflicting hypotheses. Ribosomes may undergo a single cycle of forward and backward rotations per codon read. Alternatively, in addition to rotations caused by peptidyl transfer and translocation, ribosomes may undergo multiple full spontaneous rotations, with these rotations playing a critical role in elongation and specifically in translocation mechanism. We applied high-speed single-molecule TIRF microscopy to follow translation in real-time. Actively translating ribosomes undergo partial spontaneous rotations between three different rotational states. Spontaneous rotations are restricted prior to A-site tRNA decoding. Peptidyl transfer unlocks spontaneous rotations. Consequently, translocation proceeds via a novel rotational state induced by EF-G. Our results bridge both models and provide a coherent view of ribosome dynamics during translation.