scholarly journals On the Expressive Power of Global and Local Priority in Process Calculi

2007 ◽  
pp. 241-255 ◽  
Author(s):  
Cristian Versari ◽  
Nadia Busi ◽  
Roberto Gorrieri
Keyword(s):  
Expressive Power ◽  
Process Calculi ◽  
Global And Local

scholarly journals An expressiveness study of priority in process calculi

2009 ◽  
Vol 19 (6) ◽  
pp. 1161-1189 ◽  
Author(s):  
CRISTIAN VERSARI ◽  
NADIA BUSI ◽  
ROBERTO GORRIERI
Keyword(s):  
Distributed Computing ◽  
Premature Termination ◽  
Expressive Power ◽  
Leader Election ◽  
Process Algebras ◽  
Process Calculi ◽  
Global Priority ◽  
Π Calculus ◽  
Computational Systems ◽  
Separation Results

Priority is a frequently used feature of many computational systems. In this paper we study the expressiveness of two process algebras enriched with different priority mechanisms. In particular, we consider a finite (that is, recursion-free) fragment of asynchronous CCS with global priority (FAP, for short) and Phillips' CPG (CCS with local priority), and contrast their expressive power with that of two non-prioritised calculi, namely the π-calculus and its broadcast-based version, called bπ. We prove, by means of leader-election-based separation results, that, under certain conditions, there exists no encoding of FAP in π-Calculus or CPG. Moreover, we single out another problem in distributed computing, which we call the last man standing problem (LMS for short), that better reveals the gap between the two prioritised calculi above and the two non-prioritised ones, by proving that there exists no parallel-preserving encoding of the prioritised calculi in the non-prioritised calculi retaining any sincere (complete but partially correct, that is, admitting divergence or premature termination) semantics.

On the expressive power of recursion, replication and iteration in process calculi

2009 ◽  
Vol 19 (6) ◽  
pp. 1191-1222 ◽  
Author(s):  
NADIA BUSI ◽  
MAURIZIO GABBRIELLI ◽  
GIANLUIGI ZAVATTARO
Keyword(s):  
Expressive Power ◽  
The Other ◽  
Finite Convergence ◽  
Basic Properties ◽  
Process Calculi ◽  
Weak Bisimulation ◽  
Alternative Approaches ◽  
Definition Of ◽  
Recursive Definitions

In this paper we investigate the expressive power of three alternative approaches to the definition of infinite behaviours in process calculi, namely, recursive definitions, replication and iteration. We prove several results discriminating between the calculi obtained from a core CCS by adding the three mechanisms mentioned above. These results are derived by considering the decidability of four basic properties: termination (that is, all computations are finite); convergence (that is, the existence of a finite computation); barb (that is, the ability to perform an action on a given channel) and weak bisimulation.Our results, which are summarised in Table 1, show that the three calculi form a strict expressiveness hierarchy in that: all the properties mentioned are undecidable in CCS with recursion; only termination and barb are decidable in CCS with replication; all the properties are decidable in CCS with iteration.As a corollary, we also obtain a strict expressiveness hierarchy with respect to weak bisimulation, since there exist weak bisimulation preserving encodings of iteration in replication and of replication in recursion, whereas there are no weak bisimulation preserving encodings in the other directions.

Sunspot Groups as Tracers of Sub-Surface Processes

2000 ◽  
Vol 179 ◽  
pp. 155-160
Author(s):  
M. H. Gokhale
Keyword(s):  
Magnetic Flux ◽  
Indian Institute ◽  
Surface Processes ◽  
The Sun ◽  
Global And Local ◽  
Sunspot Groups

AbstractData on sunspot groups have been quite useful for obtaining clues to several processes on global and local scales within the sun which lead to emergence of toroidal magnetic flux above the sun’s surface. I present here a report on such studies carried out at Indian Institute of Astrophysics during the last decade or so.

Establishing global and local coherence in discourse processing: Evidence from fMRI

2009 ◽  
Author(s):  
Paul van den Broek ◽  
Ben Seipel ◽  
Virginia Clinton ◽  
Edward J. O'Brien ◽  
Philip Burton ◽  
...  
Keyword(s):  
Discourse Processing ◽  
Local Coherence ◽  
Global And Local

Coral husbandry for ocean futures: leveraging abiotic factors to increase survivorship, growth, and resilience in juvenile Montipora capitata

2021 ◽  
Vol 657 ◽  
pp. 123-133
Author(s):  
JR Hancock ◽  
AR Barrows ◽  
TC Roome ◽  
AS Huffmyer ◽  
SB Matsuda ◽  
...  
Keyword(s):  
Abiotic Factors ◽  
Larval Rearing ◽  
Abiotic Conditions ◽  
Montipora Capitata ◽  
Reef Restoration ◽  
Juvenile Corals ◽  
Bleaching Response ◽  
The Face ◽  
Survival And Growth ◽  
Global And Local

Reef restoration via direct outplanting of sexually propagated juvenile corals is a key strategy in preserving coral reef ecosystem function in the face of global and local stressors (e.g. ocean warming). To advance our capacity to scale and maximize the efficiency of restoration initiatives, we examined how abiotic conditions (i.e. larval rearing temperature, substrate condition, light intensity, and flow rate) interact to enhance post-settlement survival and growth of sexually propagated juvenile Montipora capitata. Larvae were reared at 3 temperatures (high: 28.9°C, ambient: 27.2°C, low: 24.5°C) for 72 h during larval development, and were subsequently settled on aragonite plugs conditioned in seawater (1 or 10 wk) and raised in different light and flow regimes. These juvenile corals underwent a natural bleaching event in Kāne‘ohe Bay, O‘ahu, Hawai‘i (USA), in summer 2019, allowing us to opportunistically measure bleaching response in addition to survivorship and growth. This study demonstrates how leveraging light and flow can increase the survivorship and growth of juvenile M. capitata. In contrast, larval preconditioning and substrate conditioning had little overall effect on survivorship, growth, or bleaching response. Importantly, there was no optimal combination of abiotic conditions that maximized survival and growth in addition to bleaching tolerances. This study highlights the ability to tailor sexual reproduction for specific restoration goals by addressing knowledge gaps and incorporating practices that could improve resilience in propagated stocks.

The Indices of Creative Cities: the Global and Local Aspects

2015 ◽  
Vol 4 (1) ◽  
pp. 95 ◽  
Author(s):  
Tomas Kačerauskas
Keyword(s):  
High Tech ◽  
Melting Pot ◽  
Creative Cities ◽  
Global And Local

The paper deals with the indices of creative cities. Author analyses the different creativity indices suggested by both the followers and the critics of R. Florida. The author criticizes the Florida’s indices such as Bohemian, Melting pot, Gay, High tech, Innovation, Talent indices, as well as Minor integrative (diversity) and Major integrative indices. The indices of other authors presuppose the questions about the role of the region in defining certain creativity indices. The author makes conclusion that the uniform formula of creativity indices is impossible for two reasons. First, the creativity indices depend on the region of a city. Second, the very strategy to have the uniform creativity indices makes the cities similar to each other and no more unique, consequently, no more creative; as result, this strategy is anti-creative.

Investigation of Timing Anomalies in the Russian Stock Market in the Post-Crisis Period

2019 ◽  
Vol 12 (3) ◽  
pp. 37-47
Author(s):  
I. Ya. Lukasevich
Keyword(s):  
Stock Market ◽  
Information Technologies ◽  
Real Data ◽  
Weak Form ◽  
Fair Value ◽  
Presidential Decree ◽  
Day Of The Week ◽  
Russian Stock Market ◽  
Economic Growth Rates ◽  
Global And Local

The implementation of the May presidential decree aimed at Russia’s joining the top five global economies and achieving economic growth rates above the world’s average while maintaining macroeconomic stability requires a highly developed and efficient stock market ensuring the accumulation of capital and its deployment in the most promising and productive sectors of the economy.The subject of the research is timing anomalies in the Russian stock market in 2012–2018. The relevance of the research is due to the information inefficiency of the Russian stock market and its imperfections leading to significant price deviations from the «fair» value of assets and depriving investors of the opportunity to form various strategies for deriving additional revenues not related to fundamental economic factors and objective processes occurring in the global and local economies and the economy of an individual business entity. Based on the trend analysis of the Broad Market USD Index (RUBMI), the paper demonstrates a methodology for simulating the analysis of price anomalies on large arrays of real data using statistical data processing methods and modern information technologies. The paper concludes that though the Russian stock market lacks even the weak form of efficiency, such well-known timing anomalies as the “day-of-the-week” effect and the “month” effect have not been observed in the recent years. Therefore, investors could not use these anomalies to derive regular revenues above the market average.

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