The Experts below are selected from a list of 165 Experts worldwide ranked by ideXlab platform
Steen Rasmussen - One of the best experts on this subject based on the ideXlab platform.
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Recursive Definition of global cellular automata mappings
Physical Review E, 1994Co-Authors: Rasmus Feldberg, Carsten Knudsen, Steen RasmussenAbstract:A method for a Recursive Definition of global cellular-automata mappings is presented. The method is based on a graphical representation of global cellular-automata mappings. For a given cellular-automaton rule the Recursive algorithm defines the change of the global cellular-automaton mapping as the number of lattice sites is incremented. A proof of lattice size invariance of global cellular-automata mappings is derived from an approximation to the exact Recursive Definition. The Recursive Definitions are applied to calculate the fractal dimension of the set of reachable states and of the set of fixed points of cellular automata on an infinite lattice.
Rasmus Feldberg - One of the best experts on this subject based on the ideXlab platform.
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Recursive Definition of global cellular automata mappings
Physical Review E, 1994Co-Authors: Rasmus Feldberg, Carsten Knudsen, Steen RasmussenAbstract:A method for a Recursive Definition of global cellular-automata mappings is presented. The method is based on a graphical representation of global cellular-automata mappings. For a given cellular-automaton rule the Recursive algorithm defines the change of the global cellular-automaton mapping as the number of lattice sites is incremented. A proof of lattice size invariance of global cellular-automata mappings is derived from an approximation to the exact Recursive Definition. The Recursive Definitions are applied to calculate the fractal dimension of the set of reachable states and of the set of fixed points of cellular automata on an infinite lattice.
Bin Jiang - One of the best experts on this subject based on the ideXlab platform.
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a Recursive Definition of goodness of space for bridging the concepts of space and place for sustainability
Sustainability, 2019Co-Authors: Bin JiangAbstract:Conceived and developed by Christopher Alexander through his life’s work, The Nature of Order, wholeness is defined as a mathematical structure of physical space in our surroundings. Yet, there was no mathematics, as Alexander admitted then, that was powerful enough to capture his notion of wholeness. Recently, a mathematical model of wholeness, together with its topological representation, has been developed that is capable of addressing not only why a space is good, but also how much goodness the space has. This paper develops a structural perspective on goodness of space (both large- and small-scale) in order to bridge two basic concepts of space and place through the very concept of wholeness. The wholeness provides a de facto Recursive Definition of goodness of space from a holistic and organic point of view. A space is good, genuinely and objectively, if its adjacent spaces are good, the larger space to which it belongs is good, and what is contained in the space is also good. Eventually, goodness of space, or sustainability of space, is considered a matter of fact rather than of opinion under the new view of space: space is neither lifeless nor neutral, but a living structure capable of being more living or less living, or more sustainable or less sustainable. Under the new view of space, geography or architecture will become part of complexity science, not only for understanding complexity, but also for making and remaking complex or living structures.
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a Recursive Definition of goodness of space for bridging the concepts of space and place for sustainability
arXiv: Physics and Society, 2019Co-Authors: Bin JiangAbstract:Conceived and developed by Christopher Alexander through his life's work: The Nature of Order, wholeness is defined as a mathematical structure of physical space in our surroundings. Yet, there was no mathematics, as Alexander admitted then, that was powerful enough to capture his notion of wholeness. Recently, a mathematical model of wholeness, together with its topological representation, has been developed that is capable of addressing not only why a space is good, but also how much goodness the space has. This paper develops a structural perspective on goodness of space - both large- and small-scale - in order to bridge two basic concepts of space and place through the very concept of wholeness. The wholeness provides a de facto Recursive Definition of goodness of space from a holistic and organic point of view. A space is good, genuinely and objectively, if its adjacent spaces are good, the larger space to which it belongs is good, and what is contained in the space is also good. Eventually, goodness of space - sustainability of space - is considered a matter of fact rather than of opinion under the new view of space: space is neither lifeless nor neutral, but a living structure capable of being more living or less living, or more sustainable or less sustainable. Under the new view of space, geography or architecture will become part of complexity science, not only for understanding complexity, but also for making and remaking complex or living structures. Keywords: Scaling law, head/tail breaks, living structure, beauty, streets, cities
Carsten Knudsen - One of the best experts on this subject based on the ideXlab platform.
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Recursive Definition of global cellular automata mappings
Physical Review E, 1994Co-Authors: Rasmus Feldberg, Carsten Knudsen, Steen RasmussenAbstract:A method for a Recursive Definition of global cellular-automata mappings is presented. The method is based on a graphical representation of global cellular-automata mappings. For a given cellular-automaton rule the Recursive algorithm defines the change of the global cellular-automaton mapping as the number of lattice sites is incremented. A proof of lattice size invariance of global cellular-automata mappings is derived from an approximation to the exact Recursive Definition. The Recursive Definitions are applied to calculate the fractal dimension of the set of reachable states and of the set of fixed points of cellular automata on an infinite lattice.
Carolina Dania - One of the best experts on this subject based on the ideXlab platform.
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SQL-PL4OCL: An Automatic Code Generator from OCL to SQL Procedural Language
2017 ACM IEEE 20th International Conference on Model Driven Engineering Languages and Systems (MODELS), 2017Co-Authors: Marina Egea, Carolina DaniaAbstract:Design models are widely spread as core artifacts in software engineering. Yet, a key problem is how to fulfill correctly these blueprint specifications when code components are developed. The best possible scenario occurs when a source modeling language can be perfectly linked to a target language of election. Namely, a well defined mapping bridges the gap between the source and the target language. Otherwise, manual encoding of the system design is cumbersome and error prone. In this setting, we introduce a SQL-PL code generator for OCL expressions that, in contrast to other proposals, is able to map OCL iterate and iterator expressions thanks to our use of stored procedures. More in detail, our source language is the Object Constraint Language (OCL), which nowadays is an ISO standard used to express constraints and queries in a textual notation on UML models. Our target language is the procedural language (PL) extension to the Structured Query Language (SQL). SQL is a special-purpose programming language designed for managing data in relational database management systems (RDBMS). The purpose of PL for SQL is to combine database language and procedural programming language. Although SQL is also an ISO standard, different RDBMS implement certain syntactic variations to the standard SQL notation. Thus, we had to adapt the implementation of our mapping to each of them. As implementation targets we selected MariaDB, PostgreSQL, and MS SQL Server. MariaDB and PostgreSQL were selected because they are open source and widely used by developers. MS SQL server was selected to be able to compare evaluation time from open source to commercial RDBMS. A variety of applications arises for a mapping from OCL to SQL expressions. Among others, there are three prominent types. These are i) evaluation of OCL expressions (analysis queries and metrics) on large model's instances, ii) identification of constraints during data modeling that have to be checked as integrity constraints on actual data; iii) automatic code generation from models. Indeed, our implementation was used as a key component of a toolkit that automatically generated ready-to-deploy web applications for secure data management from design models. Our component mapped and evaluated OCL constraints specified within authorization policies. Our code generator is defined Recursively over the structure of OCL expressions and it is implemented in the SQL-PL4OCL tool that is publicly available at [1]. The seminal work of the mapping presented here can be found in [2], [3]. The key idea that enables the mapping from OCL iterator expressions to iterative stored procedures remains the same, but the work detailed in [4] introduces a novel mapping from OCL expressions to SQL-PL stored procedures. In the novel mapping we have taken design decisions which have facilitated the Recursive Definition of the code generator and simplified its Definition. These decisions have also helped to significantly decrease the time required for the evaluation of the code generated. Regarding semantics, the new mapping is able to deal properly with the three-valued evaluation semantics of OCL. In addition, our original work and implementation was intended only for the procedural extension of MySQL, while our new Definition eased the implementation of the mapping into other relational database management systems. In turn, we can now evaluate the resulting code using different RDBMS, which permits us to widen our discussion regarding efficiency in terms of evaluation-time of the code produced by SQL-PL4OCL tool.