scholarly journals Equivalence checking for weak bi-Kleene algebra

2021 ◽  
Vol Volume 17, Issue 3 ◽  
Author(s):  
Tobias Kappé ◽  
Paul Brunet ◽  
Bas Luttik ◽  
Alexandra Silva ◽  
Fabio Zanasi
Keyword(s):  
Decision Procedure ◽  
Equivalence Checking ◽  
Operational Model ◽  
Kleene Algebra ◽  
Single Thread ◽  
Rational Expressions ◽  
Language Equivalence

Pomset automata are an operational model of weak bi-Kleene algebra, which describes programs that can fork an execution into parallel threads, upon completion of which execution can join to resume as a single thread. We characterize a fragment of pomset automata that admits a decision procedure for language equivalence. Furthermore, we prove that this fragment corresponds precisely to series-rational expressions, i.e., rational expressions with an additional operator for bounded parallelism. As a consequence, we obtain a new proof that equivalence of series-rational expressions is decidable.

scholarly journals Visibly Pushdown Automata: From Language Equivalence to Simulation and Bisimulation

2006 ◽  
Vol 13 (13) ◽  
Author(s):  
Jirí Srba
Keyword(s):  
Lower Bound ◽  
Lower Bounds ◽  
Process Algebra ◽  
Upper And Lower Bounds ◽  
Equivalence Checking ◽  
Basic Process ◽  
Bisimulation Equivalence ◽  
Language Equivalence ◽  
Visibly Pushdown Automata ◽  
Pushdown Automata

We investigate the possibility of (bi)simulation-like preorder/equivalence checking on the class of visibly pushdown automata and its natural subclasses visibly BPA (Basic Process Algebra) and visibly one-counter automata. We describe generic methods for proving complexity upper and lower bounds for a number of studied preorders and equivalences like simulation, completed simulation, ready simulation, 2-nested simulation preorders/equivalences and bisimulation equivalence. Our main results are that all the mentioned equivalences and preorders are EXPTIME-complete on visibly pushdown automata, PSPACE-complete on visibly one-counter automata and P-complete on visibly BPA. Our PSPACE lower bound for visibly one-counter automata improves also the previously known DP-hardness results for ordinary one-counter automata and one-counter nets. Finally, we study regularity checking problems for visibly pushdown automata and show that they can be decided in polynomial time.

Psychometric Parameters of the Spanish Version of the Kuwait University Anxiety Scale (S-KUAS)1

2004 ◽  
Vol 20 (4) ◽  
pp. 349-357 ◽  
Author(s):  
Ahmed M. Abdel-Khalek ◽  
Joaquin Tomás-Sabádo ◽  
Juana Gómez-Benito
Keyword(s):  
Reliability And Validity ◽  
Anxiety Scale ◽  
Spanish Version ◽  
Good Reliability ◽  
Kuwait University ◽  
Males And Females ◽  
Anxiety Levels ◽  
Arabic And English ◽  
Cross Language ◽  
Language Equivalence

Summary: To construct a Spanish version of the Kuwait University Anxiety Scale (S-KUAS), the Arabic and English versions of the KUAS have been separately translated into Spanish. To check the comparability in terms of meaning, the two Spanish preliminary translations were thoroughly scrutinized vis-à-vis both the Arabic and English forms by several experts. Bilingual subjects served to explore the cross-language equivalence of the English and Spanish versions of the KUAS. The correlation between the total scores on both versions was .93, and the t value was .30 (n.s.), denoting good similarity. The Alphas and 4-week test-retest reliabilities were greater than .84, while the criterion-related validity was .70 against scores on the trait subscale of the STAI. These findings denote good reliability and validity of the S-KUAS. Factor analysis yielded three high-loaded factors of Behavioral/Subjective, Cognitive/Affective, and Somatic Anxiety, equivalent to the original Arabic version. Female (n = 210) undergraduates attained significantly higher mean scores than their male (n = 102) counterparts. For the combined group of males and females, the correlation between the total score on the S-KUAS and age was -.17 (p < .01). By and large, the findings of the present study provide evidence of the utility of the S-KUAS in assessing trait anxiety levels in the Spanish undergraduate context.

Transitioning Business for a Circular Economy

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Susan EVANS
Keyword(s):  
Professional Practice ◽  
Circular Economy ◽  
Radical Change ◽  
Virtual Space ◽  
Professional Experience ◽  
Operational Model ◽  
New Vision ◽  
To Come ◽  
Space Requirements

This case study explores the strategic business opportunities, for Lane Crawford, an iconic luxury department store, to transition in a circular economy towards sustainability. A new experimentation framework was developed and conducted among cross departmental employees, during a Design Lab, with intention to co-create novel Circular Economy business concepts towards a new vision: the later was a reframe of the old system based on the principles of sustainability; to move beyond a linear operational model towards a circular economy that can contribute to a regenerative society. This work draws on both academic and professional experience and was conducted through professional practice. It was found that innovative co-created concepts, output from the Design Lab, can create radical change in a circular economy that is holistically beneficial and financially viable; looking forward to extract greater value a)Internal organization requires remodeling to transform towards a circular economy; b)Requirement for more horizonal teams across departments vs solely vertical; c)New language and relationships are required to be able to transition towards a circular economy; d)Some form of physical and virtual space requirements, for cross-disciplinary teams to come together to co-create; e)Ability to iterate, learn and evolve requires agency across the business

A Decision Procedure for Bit-Vector Arithmetic

1998 ◽  
Author(s):  
Clark W. Barrett ◽  
David L. Dill ◽  
Jeremy R. Levitt
Keyword(s):  
Decision Procedure ◽  
Bit Vector
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