Denotational semantics of channel mobility in UTP-CSP

In this paper, we present the denotational semantics for channel mobility in the Unifying Theories of Programming (UTP) semantics framework. The basis for the model is the UTP theory of reactive processes, precisely, the UTP semantics for Communicating Sequential Processes (CSP), which is extended to allow the mobility of channels—the set of channels that a process can use for communication (its interface), originally static or constant (set during the process's definition), is now made dynamic or variable: it can change during the process's execution. A channel is thus moved around by communicating it via other channels and then allowing the receiving process to extend its interface with the received channel. We introduce a new concept, the capability of a process, which allows separating the ownership of channels from the knowledge of their existence. Mobile processes are then defined as having a static capability and a dynamic interface. Operations of a mobile telecommunications network, e.g., handover, load balancing, are used to illustrate the semantics. We redefine CSP operators and in particular provide the first semantics for the renaming and hiding operators in the context of channel mobility.

Human development and population mobility through the prism of national features: socio-economic dimension and management concept

The relevance of the human development study in the context of mobile processes is substantiated. The difference between human development and the level and quality of life, well-being, human resources development, and sustainable development is determined. Problematic aspects of human development in Ukraine are analyzed. Negative economic determinations of human development in Ukraine intensify mobile processes, which is confirmed by the migration situation. The country's economy is becoming dependent on migration, which creates numerous risks of socio-economic and political nature. It is necessary to develop the conceptual foundations of human development policy in a highly mobile society for their leveling. Such a policy is proposed to be considered as a set of measures aimed at forming a favorable internal environment of human life with respect for the rights and freedoms of choice and movement, preserving the possibility of return and protection of citizens regardless of location. An appropriate concept for the formation of human development policy in a highly mobile society in Ukraine should be developed. The concept should combine three blocks of goals: general provisions of security, principles of regulation of movements, which apply to all categories of mobile persons, the purpose of which is to preserve social unity in conditions of a highly mobile society by increasing its spiritual and informational mobility; internal mobility with the aim of ensuring the redistribution of human potential according to the peculiarities of regional development, the high-quality infrastructure of internal movements for the formation of flexible relational human space, as well as direct and indirect impact on mobility through improving the human development environment (output vector). The latest paradigm of human development of a highly mobile society should be formed on the basis of the concept implementation in the ideological plan at the national level.

Response

This special section elucidates intersections between the historiography of mobilities and the interdisciplinary field of mobilities research. The articles highlight relationships between mobilities and stabilization, circulation and place-making, deterritorialization and reterritorialization. This response essay seeks to dispel three myths about mobility studies: (1) that it is purely about the contemporary world, rather than the historical dimensions of mobile processes; (2) that it focuses solely on material phenomenon of physical transport (i.e., of things and people) and ignores the movement of ideas, knowledge, and culture; and (3) that it is purely about “flows” and “circulation” and has little to teach us about friction, resistances, blockages, or uneven power relations. The most important intersections of the histories of mobilities and the field of mobility studies can be found in the ways in which each emphasizes power differentials, blockages, friction, and the relation between mobilities and immobilities.

Even Simple Processes of π-calculus are Hard for Analysis

Mathematical models of distributed computations, based on the calculus of mobile processes (π-calculus) are widely used for checking the information security properties of cryptographic protocols. Since π-calculus is Turing-complete, this problem is undecidable in general case. Therefore, the study is carried out only for some special classes of π-calculus processes with restricted computational capabilities, for example, for non-recursive processes, in which all runs have a bounded length, for processes with a bounded number of parallel components, etc. However, even in these cases, the proposed checking procedures are time consuming. We assume that this is due to the very nature of the π -calculus processes. The goal of this paper is to show that even for the weakest model of passive adversary and for relatively simple protocols that use only the basic π-calculus operations, the task of checking the information security properties of these protocols is co-NP-complete.

Pitfall in Echocardiography: infective endocarditis or valvular strand? Case report

Lambl’s excrescences are thin filiform mobile processes with thin attachment at valvular closure lines. In this case report we describe the transesophageal views of Lambl’s excrescences; our case is meant to serve as a classic example of this com- monly misinterpreted lesion.

The Rigid Origami Patterns for Flat Surface

Because of the internal mobility, rigid origami structures have great potential in engineering applications. In this research, a kinematic model of the rigid origami pattern is proposed based on the assembly of spherical 4R linkages. To ensure the rigid origami pattern with mobility one, the kinematic and geometric compatibility conditions of the kinematic model are derived. Four types of flat rigid origami patterns are obtained, including three existing types as well as a novel one called the supplementary type. To testify and display the mobile processes of the patterns, their simulation models are built accordingly.