Using analog computers in today's largest computational challenges

Analog computers can be revived as a feasible technology platform for low precision, energy efficient and fast computing. We justify this statement by measuring the performance of a modern analog computer and comparing it with that of traditional digital processors. General statements are made about the solution of ordinary and partial differential equations. Computational fluid dynamics are discussed as an example of large scale scientific computing applications. Several models are proposed which demonstrate the benefits of analog and digital-analog hybrid computing.

STUDYING THE PROBLEMS OF APPLIED POLITICAL SCIENCE IN THE PROCESS OF TEACHING POLITICAL SCIENCE

The article is devoted to the methodological problems of studying the section "Applied Political Sci-ence" in the course of political science. Revealed its role in the educational process, the relationship with other sections of the discipline. The structure of applied political science, its subject, methods and specificity in relation to theoretical political science are shown. Analyzed the most important problems that need to be considered in the study of applied political science. Particular attention is paid to the analysis of political forecasting and its importance in the management of social and political events and processes. The essence and basic principles of political modeling, the typology of models: material, analog, computer, etc. are con-sidered. Methodological recommendations are given for considering the topics of the section in lectures and practical classes, their importance in the professional training of bachelors is shown.

Tracking computability of GPAC-generable functions

Analog computation attempts to capture any type of computation, that can be realized by any type of physical system or physical process, including but not limited to computation over continuous measurable quantities. A pioneering model is the General Purpose Analog Computer (GPAC), initially presented by Shannon in 1941. The GPAC is capable of manipulating real-valued data streams; however, it has been shown to be strictly less powerful than other models of computation on the reals, such as computable analysis. In previous work, we proposed an extension of the Shannon GPAC, denoted LGPAC, designed to overcome its limitations. Not only is the LGPAC model capable of expressing computation over general data spaces $\mathcal{X}$, but it also directly incorporates approximating computations by means of a limit module. An important feature of this work is the generalisation of the framework of the computation theory from Banach to Fréchet spaces. In this paper, we compare the LGPAC with a digital model of computation based on effective representations (tracking computability). We establish general conditions under which LGPAC-generable functions are tracking computable.

Effects of Symmetric and Asymmetric Nonlinearity on the Dynamics of a Third-Order Autonomous Duffing–Holmes Oscillator

A generalized third-order autonomous Duffing–Holmes system is proposed and deeply investigated. The proposed system is obtained by adding a parametric quadratic term m x 2 to the cubic nonlinear term − x 3 of an existing third-order autonomous Duffing–Holmes system. This modification allows the system to feature smoothly adjustable nonlinearity, symmetry, and nontrivial equilibria. A particular attention is given to the effects of symmetric and asymmetric nonlinearity on the dynamics of the system. For the specific case of m = 0 , the system is symmetric and interesting phenomena are observed, namely, coexistence of symmetric bifurcations, presence of parallel branches, and the coexistence of four (periodic-chaotic) and six (periodic) symmetric attractors. For m ≠ 0 , the system loses its symmetry. This favors the emergence of other behaviors, such as the coexistence of asymmetric bifurcations, involving the coexistence of several asymmetric attractors (periodic-periodic or periodic-chaotic). All these phenomena have been numerically highlighted using nonlinear dynamic tools (bifurcation diagrams, Lyapunov exponents, phase portraits, time series, frequency spectra, Poincaré section, cross sections of the attraction basins, etc.) and an analog computer of the system. In fact, PSpice simulations of the latter confirm numerical results. Moreover, amplitude control and synchronization strategies are also provided in order to promote the exploitation of the proposed system in engineering.

From the Display of a Digital-Masculine Machine to the Concealed Analog-Feminine Labour: The Passage from the History of Technology to Labour and Gender History

The article introduces the essentialist 1940s demarcation between a digital-superior and an analog-inferior computer as a key moment in severing the computing machine from the human worker labouring with it, and, accordingly, to keeping the history of computing technology and the history of computing labour apart. It starts with a section that further argues that the introduction of this key demarcation is strongly linked to the transition from the prewar use of the concept “computer”, which referred to a human worker, to its postwar use, which refers to a computing machine. The argument comes full circle by connecting the concealed analog to hidden female computing labour, a connection suggested by a revisiting of the paradigmatic display of the ENIAC as a digital machine. There follow two sections, one on the history of the female labour concealed by presenting the digital computer as superior and the other on the history of the male labour neglected by ignoring the analog computer as inferior.