The semigroup of a strongly connected automaton

1977 ◽  
Vol 15 (1) ◽  
pp. 351-356 ◽  
Author(s):  
Robert H. Oehmke
Keyword(s):  
Connected Automaton ◽  
Strongly Connected

On complexity reduction of the discrete-event subsystem of Flat Hybrid Automata for control design

2020 ◽  
Vol 68 (7) ◽  
pp. 529-540
Author(s):  
Tobias Kleinert ◽  
Frederik Zahn ◽  
Veit Hagenmeyer
Keyword(s):  
Heuristic Algorithm ◽  
Adjacency Matrix ◽  
Discrete Event ◽  
Control Design ◽  
Differential Flatness ◽  
Hybrid Automata ◽  
Connected Automaton ◽  
Strongly Connected ◽  
Design Perspective ◽  
Technical Systems

AbstractThe class of hybrid systems describes most technical systems in great detail. However, the respective models and their behavior tend to be very complex. Recently, a new subclass of hybrid automata has been introduced, the Flat Hybrid Automata (FHA) that relies on the concepts of differential flatness for the continuous parts, and strongly connected automaton graphs for the discrete event part, in order to deal with the complexity from a design perspective. Therefore, we introduce in the present paper an approach to reduce the automaton graph of an FHA in a systematic way by removing edges from the adjacency matrix. The main contribution of the paper is twofold: Firstly, based on practical considerations we develop a heuristic algorithm to reduce the automaton graph. Secondly, we present possible ways to include knowledge about the system in the reduction.

Intimation

2017 ◽  
Author(s):  
G. R. F. Ferrari
Keyword(s):  
Social Life ◽  
Relevance Theory ◽  
Self Presentation ◽  
Erving Goffman ◽  
Strongly Connected ◽  
Dan Sperber ◽  
Paul Grice

The communicative scale is introduced. What is fundamental to communication is the intention of the communicator rather than the codes that languages employ. Following the model first proposed by Paul Grice and developed in Dan Sperber and Deirdre Wilson’s ‘relevance theory’, the structure of communicative intentionality is understood to be recursive: its underlying form is ‘I want you to know that I want you to know’. This leaves room for a simpler kind of transmission, to be called ‘intimation’, whose underlying form would be ‘I want you to know’. If communication is a transmission at the ‘full-on’ position of the scale, and if the switch is off when no communication is intended, then intimation would be at the intermediate, ‘half-on’ position. Intimation is particularly useful in contexts where discretion, suggestiveness, or plausible deniability are needed. It is strongly connected to self-presentation in social life (as studied by Erving Goffman).

scholarly journals The Nexus of Sophisticated Digital Assets with Economic Policy Uncertainty: A Survey of Empirical Findings and an Empirical Investigation

2021 ◽  
Vol 13 (10) ◽  
pp. 5383
Author(s):  
Nikolaos A. Kyriazis
Keyword(s):  
Economic Policy ◽  
Empirical Investigation ◽  
Econometric Analysis ◽  
Policy Uncertainty ◽  
Negative Effects ◽  
Economic Policy Uncertainty ◽  
Strongly Connected ◽  
Threshold Arch ◽  
Best Fit ◽  
Digital Assets

This paper sets out to explore the nexus between economic policy uncertainty (EPU) and digital currencies. An integrated survey takes place based on eleven primary studies. Furthermore, an econometric analysis is conducted by the threshold ARCH, simple asymmetric ARCH and non-linear ARCH specifications covering the bull and the bear markets as well as the highly volatile period up to the present. Threshold ARCH is found to provide the best fit for estimations. Outcomes reveal that Bitcoin is strongly connected with EPU while Ethereum and Litecoin are not but are strongly linked with Bitcoin performance. Moreover, weak negative effects of the VIX on both cryptocurrencies are detected while oil exerts weak positive impacts on Ethereum. Overall, Ethereum and Litecoin could serve for diversifiers against Bitcoin or hedgers against traditional assets during highly stressed periods with the advantage of not being affected by economic policy uncertainty news.

scholarly journals Nisyros Volcanic Island: A Geosite through a Tailored GIS Story

Geosciences ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 132
Author(s):  
Varvara Antoniou ◽  
Paraskevi Nomikou ◽  
Dimitrios Panousis ◽  
Effrosyni Zafeirakopoulou
Keyword(s):  
Spatial Data ◽  
Hot Springs ◽  
Volcanic Rocks ◽  
Data Communication ◽  
Aegean Sea ◽  
Volcanic Island ◽  
Eastern Aegean ◽  
Strongly Connected ◽  
Historical Heritage ◽  
Available Information

The volcanic island of Nisyros (Greece) is here presented as it presents unique characteristics being a Quaternary volcano in the eastern Aegean Sea, composed of volcanic rocks, and featuring a central caldera that is surrounded by volcanic domes and thick lavas. Its history is strongly connected to the volcano impressing the visitors with steaming hydrothermal craters, intensive smell of sulfur and fumarolic gases, and hot springs. Due to its morphology and geographical position, its cultural and historical heritage has been unchanged in time, bequeath to the island plenty of churches, monasteries with hagiographic frescoes, castles, caves, and spas. To present the geodiversity, the cultural environment, and the biodiversity of this geosite, a relatively new geographic approach was used, ESRI Story Maps. Being web-based applications, they are widespread as an interactive responsive tool used for spatial data communication and dissemination, by combining thematic 2D and 3D webmaps, narrative text, and multimedia content. Such applications can be an ideal way for presenting the available information of places characterized as geosites or protected areas worldwide, providing quick access to the available information to a broader, non-technical audience, developing the interest, and possibly motivating the public to learn more or visit them.

Flow Coefficient Evaluation of Poppet Valves Used in Reciprocating Compressors for LDPE

2008 ◽  
Author(s):  
Enzo Giacomelli ◽  
Massimo Schiavone ◽  
Fabio Manfrone ◽  
Andrea Raggi
Keyword(s):  
Pressure Drop ◽  
Time Pressure ◽  
Experimental Tests ◽  
Operating Conditions ◽  
Flow Coefficient ◽  
Operating Life ◽  
High Fatigue ◽  
Strongly Connected ◽  
And Performance ◽  
Poppet Valves

Poppet valves have been used for a long time for very high pressure reciprocating compressors, as for example in the case of Low Density Polyethylene. These applications are very critical because the final pressure can reach 350 MPa and the evaluation of the performance of the machines is strongly connected to the proper operation and performance of the valve itself. The arrangement of cylinders requires generally a certain compactness of valve to withstand high fatigue stresses, but at the same time pressure drop and operating life are very important. In recent years the reliability of the machines has been improving over and over and the customers’ needs are very stringent. Therefore the use of poppet valves has been extended to other cases. In general the mentioned applications are heavy duty services and the simulation of the valves require some coefficients to be used in the differential equations, able to describe the movement of plate/disk or poppet and the flow and related pressure drop through the valves. Such coefficients are often determined in an experimental way in order to have a simulation closer to the real operating conditions. For the flow coefficients it is also possible today to use theoretical programs capable of determining the needed values in a quick and economical way. Some investigations have been carried out to determine the values for certain geometries of poppet valves. The results of the theory have been compared with some experimental tests. The good agreement between the various methods indicates the most suitable procedure to be applied in order to have reliable data. The advantage is evident as the time necessary for the theoretical procedure is faster and less expensive. This is of significant importance at the time of the design and also in case of a need to provide timely technical support for the operating behavior of the valves. Particularly for LDPE, the optimization of all the parameters is strongly necessary. The fatigue stresses of cylinder heads and valve bodies have to match in fact with gas passage turbulence and pressure drop, added to the mechanical behavior of the poppet valve components.

Sign in / Sign up

Export Citation Format

Share Document