Pattern Instantiation Research Articles

Polynomial-Time Under-Approximation of Winning Regions in Parity Games

We propose a pattern for designing algorithms that run in polynomial time by construction and under-approximate the winning regions of both players in parity games. This approximation is achieved by the interaction of finitely many aspects governed by a common ranking function, where the choice of aspects and ranking function instantiates the design pattern. Each aspect attempts to improve the under-approximation of winning regions or decrease the rank function by simplifying the structure of the parity game. Our design pattern is incremental as aspects may operate on the residual game of yet undecided nodes. We present several aspects and one higher-order transformation of our algorithms — based on efficient, static analyses — and illustrate the benefit of their interaction as well as their relative precision within pattern instantiations. Instantiations of our design pattern can be applied for local model checking and as preprocessors for algorithms whose worst-case running time is exponential. This design pattern and its aspects have already been implemented in [H. Wang. Framework for Under-Approximating Solutions of Parity Games in Polynomial Time. MEng Thesis, Department of Computing, Imperial College London, 78 pages, June 2007].

Semantic patterns for user‐interactive question answering

AbstractA new type of semantic pattern is proposed in this paper, which can be used by users to post questions and answers in user‐interactive question answering (QA) systems. The necessary procedures of using semantic patterns in a QA system are also presented, which include question structure analysis, pattern matching, pattern generation, pattern classification and answer extraction. Both the manual creation method and the automatic generation method are proposed for patterns for different applications. A pattern instantiation level metrics is also presented for the predication of the quality of generated or learned patterns. We implemented a user interface for using the semantic pattern in our QA system, which allows users to effectively post and answer questions. Copyright © 2007 John Wiley & Sons, Ltd.

Towards a web of patterns

Design patterns have been used successfully in recent years in the software engineering community in order to share knowledge about the structural and behavioural properties of software. There is a growing body of research in the area of design pattern detection and design recovery, requiring a formal description of patterns which can be matched by tools against the software that is to be analysed. We propose a novel approach to the formal definition of design patterns that is based on the idea that design patterns are knowledge that is shared across a community and that is by nature distributed and inconsistent. By using the web ontology language (OWL) we are able to formally define design patterns and some related concepts such as pattern participant, pattern refinement, and pattern instance. We discuss the respective ontology and give examples of how patterns can be defined using this ontology. We present the prototype of a Java client that accesses the pattern definitions and detects patterns in Java software, and analyse some scan results. This leads to the discussion on design pattern instantiation.

Towards a Web of Patterns

Design patterns have been used successfully in recent years in the software engineering community in order to share knowledge about the structural and behavioural properties of software. There is a growing body of research in the area of design pattern detection and design recovery, requiring a formal description of patterns which can be matched by tools against the software that is to be analysed. We propose a novel approach to the formal definition of design patterns that is based on the idea that design patterns are knowledge that is shared across a community and that is by nature distributed and inconsistent. By using the web ontology language (OWL) we are able to formally define design patterns and some related concepts such as pattern participant, pattern refinement, and pattern instance.We discuss the respective ontology and give examples of how patterns can be defined using this ontology.We present the prototype of a Java client that accesses the pattern definitions and detects patterns in Java software, and analyse some scan results. This leads to the discussion on design pattern instantiation.

A Role-Based Approach to Design Pattern Modeling and Implementation

Although design pattern is quite useful in software reuse, there are still many barriers when instantiating the design patterns, such as pattern overlapping, traceability, and difficulties in reusing the pattern code. A role-based approach for design pattern modeling and implementation is proposed. In this approach, roles of pattern are treated as the independent modeling elements and the RoleOf relationship is used to associate a role with an application class. This can improve the reusability of pattern. The meta-model of the RoleOf relationship for pattern instantiation and its semantics are proposed using UML extension mechanism. The stereotypes and tagged values used for identifying pattern information are provided, and it resolves the traceability and overlapping problem in pattern instantiation. The dynamic binding of application and role logic are implemented through the extension to Java language, called Rava. The approach proposed in this paper can effectively solve the problem such as pattern overlapping and traceability during the pattern instantiation, which improves the reusability of pattern logic and guides the software development using design patterns.