1,720,963 research outputs found
Pope Gregory's care of the Papal Estates from 590 to 604, as shown in his letters to his stewards
No full text(First paragraph) I used the "Correspondence of Pope Saint Gregory the Great,” Abbe Migne's Edition, as the principal source material. I have also employed the edition of the Epistolae published by Paul Ewald and L. M. Hartman in Monumenta Germaniae Historica (Berlin, 1887-1899), which is the best critical text available. The letters still extant total eight hundred fifty-four. On reading these, I discovered slxty addressed to various Papal agents and dealing primarily with the conduct of what is called the Patrimony of Saint Peter or the Papal Patrimony.
It is my purpose therefore to examine these letters carefully, and so to determine what may have been the policy of Gregory in his care for the Papal Estates and what he accomplished through the exercise of his authority over them as the landlord,
A man who has won the title "the Great", and retained It unchallenged down the ages, must Indeed have exercised an influence felt not only in his own day but in succeeding generations. It will be Interesting to discover to what extent Gregory’s management of the Papal Estates, as evidenced by the letters selected, helped to establish this enviable distinction.RAL Thesis 1940 G7
Formal Software Specification with Refinements and Modules of Typed Graph Transformation Systems
No full textInteractive Rule-based Specification with an Application to Visual Language Definition
No full textIn a rule-based approach the computation steps of a system are specified by rules that completely define how the system’s state may change. For open systems a more liberal approach is required, where the state changes are only partly specified, and – interactively – other com- ponents may contribute further information on how the transformation is defined completely. In this paper we introduce a formal model for in- teractive rule-based specifications, where states are modelled as partial algebras and transformations are given by internal algebra rewritings and arbitrary external components. As an application we discuss how visual languages can be defined in this framework. Thereby the internal (logical) representations of visual expressions are transformed by rewrit- ing rules, whereas their layouts are obtained interactively by external components like a constraint solver or a user working with a display and a mouse
Formal software specification with refinements and modules of typed graph transformation systems
No full textGraph transformation systems are a formal specification technique for software systems that support the rule based specification of the dynamic behaviour of a system.Their main advantages are the intuitive visual representation of states and state transformations as graphs on the one hand, and the fully formal semantics on the other hand, that allow precise statements about the specification and tool support. In this paper we introduce refinements and modules for typed graph transformation systems to support the software specification development in both dimensions: modules for the horizontal structuring of a specification, i.e., its composition from feasible parts, and refinements for the development over time
Structured Transition Systems as Lax Coalgebras
No full textThis paper relates labeled transition systems and coalgebras with the motivation of comparing and combining their complementary contributions to the theory of concurrent systems. The well-known mismatch between these two notions for what concerns the morphisms is resolved by extending the coalgebraic framework by lax cohomomorphisms.
Enriching both labeled transition systems and coalgebras with algebraic structure for an algebraic specification, the correspondence is lost again. This leads to the introduction of lax coalgebras, where the coalgebra structure is given by a lax homomorphism. The resulting category of lax coalgebras and lax cohomomorphisms for a suitable endofunctor is shown to be isomorphic to the category of structured transition systems, where both states and transitions form algebras.
The framework is also presented on a more abstract categorical level using monads and comonads, extending the bialgebraic approach recently introduced by Turi and Plotkin
An Algebra of Graph Derivations Using Finite (co-) Limit Double Theories
No full textGraph transformation systems have been introduced for the
formal specication of software systems. States are thereby modeled as
graphs, and computations as graph derivations according to the rules
of the specication. Operations on graph derivations provide means to
reason about the distribution and composition of computations. In this
paper we discuss the development of an algebra of graph derivations as a
descriptive model of graph transformation systems. For that purpose we
use a categorical three level approach for the construction of models of
computations based on structured transition systems. Categorically the
algebra of graph derivations can then be characterized as a free double
category with nite horizontal colimits.
One of the main objectives of this paper is to show how we used algebraic
techniques for the development of this formal model, in particular to
obtain a clear and well structured theory. Thus it may be seen as a
case study in theory design and its support by algebraic development
techniques
Modeling Distributed Systems by Modular Graph Transformation based on Refinement via Rule Expressions
No full textDue to the special requirements of distributed systems, it is important that modeling techniques for this kind of systems offer a stringent module concept. Each module has to support the encapsulation of data structure as well as functionality also at runtime. Modular graph transformation, presented in this contribution, supports these features. Modules are built up of specifications where attributed graphs describe the static data structures, whereas the dynamic behavior is modeled by the controlled application of graph rules. Rule expressions are used to formulate the control flow.
Within one module, we can state a (weak) preservation of export and import behavior wrt. the local behavior in the module’s body in the sense that an interface derivation is subsumed by a local derivation if it can be performed. Modules may use each other meaning that each import interface has to be connected with an export interface in a way that the import behavior is subsumed by the export behavior
A Coalgebraic presentation of structured transition systems
No full textThis paper relates labelled transition systems and coalgebras with the motivation of comparing and combining their complementary contributions to the theory of concurrent systems. The well-known mismatch between these two notions concerning the morphisms is resolved by extending the coalgebraic framework by lax cohomomorphisms.
Enriching both labelled transition systems and coalgebras with algebraic structure for an algebraic specification, the correspondence is lost again. This motivates the introduction of lax coalgebras, where the coalgebra structure is given by a lax homomorphism. The resulting category of lax coalgebras and lax cohomomorphisms for a suitable endofunctor is shown to be isomorphic to the category of structured transition systems, where both states and transitions form algebras.
The framework is also presented on a more abstract categorical level using monads and comonads, extending the bialgebraic approach introduced by Turi and Plotkin
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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