scholarly journals On the relation between reactive synthesis and supervisory control of non-terminating processes

2019 ◽  
Vol 30 (1) ◽  
pp. 81-124 ◽  
Author(s):  
Anne-Kathrin Schmuck ◽  
Thomas Moor ◽  
Rupak Majumdar

AbstractReactive synthesis and supervisory control theory both provide a design methodology for the automatic and algorithmic design of digital systems from declarative specifications. The reactive synthesis approach originates in computer science, and seeks to synthesise a system that interacts with its environment over time and that, doing so, satisfies a prescribed specification. Here, the distinguishing feature when compared to other synthesis problems in computer science is that the interaction is temporal in that it explicitly refers to a sequence of computation cycles. Supervisory control originates in control theory and seeks to synthesise a controller that – in closed-loop configuration with a plant – enforces a prescribed specification over time. The distinguishing feature compared to other branches of control is that all dynamics are driven by discrete events as opposed to continuous signals. While both methods apparently are closely related, the technical details differ significantly. We provide a formal comparison which allows us to identify conditions under which one can solve one synthesis problem using methods from the other one; we also discuss how the resulting solutions compare. To facilitate this comparison, we give a unified introduction to reactive synthesis and supervisory control and derive formal problem statements and a characterisation of their solutions in terms of ω-languages. Recent contributions to the two fields address different aspects of the respective problem, and we expect the formal relationship identified in this paper to be useful in that it allows the application of algorithmic techniques from one field in the other.

Author(s):  
Sorin Nădăban

Metric spaces and their various generalizations occur frequently in computer science applications. This is the reason why, in this paper, we introduced and studied the concept of fuzzy b-metric space, generalizing, in this way, both the notion of fuzzy metric space introduced by I. Kramosil and J. Michálek and the concept of b-metric space. On the other hand, we introduced the concept of fuzzy quasi-bmetric space, extending the notion of fuzzy quasi metric space recently introduced by V. Gregori and S. Romaguera. Finally, a decomposition theorem for a fuzzy quasipseudo- b-metric into an ascending family of quasi-pseudo-b-metrics is established. The use of fuzzy b-metric spaces and fuzzy quasi-b-metric spaces in the study of denotational semantics and their applications in control theory will be an important next step.


2006 ◽  
Vol 08 (02) ◽  
pp. 185-218 ◽  
Author(s):  
JEAN-PIERRE AUBIN ◽  
PATRICK SAINT-PIERRE

This paper deals with inertia functions in control theory introduced in Aubin, Bernardo and Saint-Pierre (2004, 2005) and their adaptation to dynamical games. The inertia function associates with any initial state-control pair the smallest of the worst norms over time of the velocities of the controls regulating viable evolutions. For tychastic systems (parameterized systems where the parameters are tyches, disturbances, perturbations, etc.), the palicinesia of a tyche measure the worst norm over time of the velocities of the tyches. The palicinesia function is the largest palicinesia threshold c such that all evolutions with palicinesia smaller than or equal to c are viable. For dynamical games where one parameter is the control and the other one is a tyche (games against nature or robust control), we define the guaranteed inertia function associated with any initial state-control-tyche triple the best of the worst of the norms of the velocities of the controls and of the tyches and study their properties. Viability Characterizations and Hamilton-Jacobi equations of which these inertia and palicinesia functions are solutions are provided.


2021 ◽  
Vol 130 (3) ◽  
pp. 339-383
Author(s):  
Sara Aronowitz

Sometimes, we face choices between actions most likely to lead to valuable outcomes, and actions which put us in a better position to learn. These choices exemplify what is called the exploration/exploitation trade-off. In computer science and psychology, this trade-off has fruitfully been applied to modulating the way agents or systems make choices over time. This article extends the trade-off to belief. We can be torn between two ways of believing, one of which is expected to be more accurate in light of current evidence, whereas the other is expected to lead to more learning opportunity and accuracy in the long run. Further, it is sometimes rationally permissible to choose the latter. The article breaks down the features of action which give rise to the trade-off, and then argues that each feature applies equally well to belief. This conclusion is an instance of a systematic, foreseeable way in which what is rational to believe now depends on what one expects to be doing in the future. That is, epistemic rationality fundamentally concerns time.


Author(s):  
Melanie K. T. Takarangi ◽  
Deryn Strange

When people are told that their negative memories are worse than other people’s, do they later remember those events differently? We asked participants to recall a recent negative memory then, 24 h later, we gave some participants feedback about the emotional impact of their event – stating it was more or less negative compared to other people’s experiences. One week later, participants recalled the event again. We predicted that if feedback affected how participants remembered their negative experiences, their ratings of the memory’s characteristics should change over time. That is, when participants are told that their negative event is extremely negative, their memories should be more vivid, recollected strongly, and remembered from a personal perspective, compared to participants in the other conditions. Our results provide support for this hypothesis. We suggest that external feedback might be a potential mechanism in the relationship between negative memories and psychological well-being.


Author(s):  
Avi Max Spiegel

This chapter seeks to understand how Islamist movements have evolved over time, and, in the process, provide important background on the political and religious contexts of the movements in question. In particular, it shows that Islamist movements coevolve. Focusing on the histories of Morocco's two main Islamist movements—the Justice and Spirituality Organization, or Al Adl wal Ihsan (Al Adl) and the Party of Justice and Development (PJD)—it suggests that their evolutions can only be fully appreciated if they are relayed in unison. These movements mirror one another depending on the competitive context, sometimes reflecting, sometimes refracting, sometimes borrowing, sometimes adapting or even reorganizing in order to keep up with the other.


2020 ◽  
Vol 65 (4) ◽  
pp. 401-422
Author(s):  
Estelle Variot
Keyword(s):  
The One ◽  

"Etymological, Lexical and Semantic Correspondences in the Process of Feminization of Professional Names, Trades and Activities in French and Romanian Societies. The feminization of thought represented by language and of its varieties in the Roman World has allowed to highlight some convergences that come from a common linguistic heritage, often from Greek and Latin and some hesitation about adapting society to its realities. The feminization of some words which comes from an ancient process illustrates on the one hand the potential of the language and on the other hand some constraints sometimes linked to the society itself, which creates transitional periods, between matching grammatical correction and the evolution of linguistic uses over time. The possibilities of lexical enrichment (internal creation or loan) show the means available in French and Romanian and some convergences in the area of derivation, of lexical units and their etymologies. The grammatical perspective and word constructing methods make it possible to give keys for the feminization of names of trades or professions. Likewise, recording entries in the lexicon, their evolution, their assimilation or sometimes their forgetfulness, for the benefit of new constructions highlight the existence of objective and subjective criteria which teach us a lot about society as a whole. Keywords: feminization of professions, internal and external enrichment, suffixal match, use of words, grammar, lexicon, French and Romanian."


2010 ◽  
Vol 1 (1) ◽  
pp. 1-19
Author(s):  
Ahmed Akgunduz

AbstractIslamic Law is one of the broadest and most comprehensive systems of legislation in the world. It was applied, through various schools of thought, from one end of the Muslim world to the other. It also had a great impact on other nations and cultures. We will focus in this article on values and norms in Islamic law. The value system of Islam is immutable and does not tolerate change over time for the simple fact that human nature does not change. The basic values and needs (which can be called maṣlaḥa) are classified hierarchically into three levels: (1) necessities (Ḍarūriyyāt), (2) convenience (Ḥājiyyāt), and (3) refinements (Kamāliyyāt=Taḥsīniyyāt). In Islamic legal theory (Uṣūl al‐fiqh) the general aim of legislation is to realize values through protecting and guaranteeing their necessities (al-Ḍarūriyyāt) as well as stressing their importance (al‐ Ḥājiyyāt) and their refinements (taḥsīniyyāt).In the second part of this article we will draw attention to Islamic norms. Islam has paid great attention to norms that protect basic values. We cannot explain all the Islamic norms that relate to basic values, but we will classify them categorically. We will focus on four kinds of norms: 1) norms (rules) concerned with belief (I’tiqādiyyāt), 2) norms (rules) concerned with law (ʿAmaliyyāt); 3) general legal norms (Qawā‘id al‐ Kulliyya al‐Fiqhiyya); 4) norms (rules) concerned with ethics (Wijdāniyyāt = Aḵlāqiyyāt = Ādāb = social and moral norms).


2020 ◽  
Author(s):  
Seng Bum Michael Yoo ◽  
Benjamin Hayden ◽  
John Pearson

Humans and other animals evolved to make decisions that extend over time with continuous and ever-changing options. Nonetheless, the academic study of decision-making is mostly limited to the simple case of choice between two options. Here we advocate that the study of choice should expand to include continuous decisions. Continuous decisions, by our definition, involve a continuum of possible responses and take place over an extended period of time during which the response is continuously subject to modification. In most continuous decisions, the range of options can fluctuate and is affected by recent responses, making consideration of reciprocal feedback between choices and the environment essential. The study of continuous decisions raises new questions, such as how abstract processes of valuation and comparison are co-implemented with action planning and execution, how we simulate the large number of possible futures our choices lead to, and how our brains employ hierarchical structure to make choices more efficiently. While microeconomic theory has proven invaluable for discrete decisions, we propose that engineering control theory may serve as a better foundation for continuous ones. And while the concept of value has proven foundational for discrete decisions, goal states and policies may prove more useful for continuous ones.


Relay Journal ◽  
2018 ◽  
pp. 360-381
Author(s):  
Gordon Myskow ◽  
Phillip A. Bennett ◽  
Hisako Yoshimura ◽  
Kyoko Gruendel ◽  
Takuto Marutani ◽  
...  

The distinction between Cooperative and Collaborative Learning approaches is not a clear one. Some use the terms interchangeably while others consider Cooperative Learning to be a type of Collaborative Learning. Still others clearly differentiate between them, characterizing Cooperative Learning as more highly structured in its procedures, involving a great deal of intervention by the teacher to plan and orchestrate group interactions. Collaborative Learning, on the other hand, presupposes some degree of learner autonomy-that groups can work effectively toward shared goals and monitor their own progress. This paper takes the view that the distinction between Cooperative and Collaborative Learning is a useful one and that both approaches can play valuable roles in fostering autonomous interaction. It argues that while Collaborative Learning formations may be the ultimate goal for teachers wishing to develop learner autonomy, Cooperative Learning is a valuable means for modeling the skills and abilities to help students get there. The discussion begins with an overview of the two approaches, focusing on their implementation in the Japanese educational context. It then presents seven highly structured Cooperative Learning activities and shows how they can be modified and extended over time to encourage more autonomous interaction.


1999 ◽  
Vol 18 (1) ◽  
pp. 1-17 ◽  
Author(s):  
Chris E. Hogan ◽  
Debra C. Jeter

Dramatic changes in recent years in the audit market suggest the timeliness of an investigation of trends in auditor concentration and an extension of prior research (e.g., Danos and Eichenseher 1982). In recent press, large audit firms have claimed that specialization is a goal of increasing importance. Peat Marwick, for example, has restructured along industry lines, claiming to be recruiting professionals for national teams of multidisciplinary experts organized to “focus on the same industry to serve clients optimally.” On the other hand, litigation concerns might prompt auditors to diversify their risks by diversifying their clientele. In this study, we examine trends in industry specialization from 1976 to 1993 and the industry factors which may affect specialization; whether market share increases are greater for audit firms classified as specialists; and whether the nation's largest audit firms have increased their market share in the industries which they have identified as their focus industries. We find evidence that concentration levels have increased over this period, consistent with the claims of the large audit firms. We find that auditor concentration levels are higher in regulated industries, in more concentrated industries and in industries experiencing rapid growth, but lower in industries with a high risk of litigation. Levels of concentration have increased over time in nonregulated industries providing evidence that scale economies or superior efficiencies of heavy-involvement auditors are not limited to regulated industries but extend to nonregulated industries as well. We also find that for the audit firms classified as market leaders at the beginning of the year, market share has increased over time, whereas market share has declined for firms with a smaller share at the beginning of the year. This suggests that there are returns to investing in specialization.


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