Pattern Instances Research Articles

Design pattern instantiation directed by concretization and specialization

Design patterns provide an especially effective way to improve the quality of a software system design as they provide abstracted, generalized and verified solutions of non-trivial design problems that occur repeatedly. The paper presents a method of design pattern instantiation support based on the key principles of both MDD and MDA. The method allows specification of the pattern instance occurrence via the semantic extension of UML directly on the context. The rest of the pattern instantiation is automated by model transformations of the specified pattern instances to lower levels of abstraction. Such approach enables the use of higher levels of abstraction in the modeling of patterns. Moreover, the model transformations are driven by models of patterns besides the instance specification, and thus the approach provides very useful ways how to determine and control the results of transformations. The method is not limited to design pattern support only, it also provides a framework for the addition of support for custom model structures which are often created in models mechanically.

Insider Threat Detection Using a Graph-Based Approach

The authors present the use of graph-based approaches to discovering anomalous instances of structural patterns in data that represent insider threat activity. The approaches presented search for activities that appear to match normal transactions, but in fact are structurally different. The authors show the usefulness of applying graph theoretic approaches to discovering suspicious insider activity in domains such as social network communications, business processes, and cybercrime. The authors present some performance results to show the effectiveness of our approaches, and then conclude with some ongoing research that combines numerical analysis with structure analysis, analyzes multiple normative patterns, and extends to dynamic graphs.

Co-Occurrence of Local Binary Patterns Features for Frontal Face Detection in Surveillance Applications

Face detection in video sequence is becoming popular in surveillance applications. The tradeoff between obtaining discriminative features to achieve accurate detection versus computational overhead of extracting these features, which affects the classification speed, is a persistent problem. This paper proposes to use multiple instances of rotational Local Binary Patterns (LBP) of pixels as features instead of using the histogram bins of the LBP of pixels. The multiple features are selected using the sequential forward selection algorithm we called Co-occurrence of LBP (CoLBP). CoLBP feature extraction is computationally efficient and produces a high-performance rate. CoLBP features are used to implement a frontal face detector applied on a 2D low-resolution surveillance sequence. Experiments show that the CoLBP face features outperform state-of-the-art Haar-like features and various other LBP features extensions. Also, the CoLBP features can tolerate a wide range of illumination and blurring changes.

Normative conflicts in electronic contracts

We are concerned with normative conflicts that arise for agents engaging in electronic contracting within an electronic marketplace. We identify a set of primitive conflict patterns, examine other analyses of conflicts found in the literature of distributed systems, legal reasoning and multi-agent interaction, and show how these may be seen as instances of primitive patterns. We also present additional patterns that have not been identified previously. Moreover, this work proposes and illustrates the representation of e-contracts in default logic, and argues that such a representation of contract norms as default rules facilitates the detection, prediction and resolution of normative conflicts.

QUESTION CLASSIFICATION USING PROFILE HIDDEN MARKOV MODELS

Recently, Question Answering has been a hot topic in the research of information retrieval. Question Classification plays a critical role in most Question Answering systems. In this paper, a new approach to classifying questions using Profile Hidden Markov Models (PHMMs) is proposed. The generalization strategies to extract the pattern instances of questions by selective substitution are discussed. Then the classification method with pattern instances' structural features is investigated. Experimental results show that the PHMM based question classifier can reach the accuracy of 92.2% and significantly outperforms most of the state-of-the-art systems.

Design pattern evolutions in QVT

One of the main goals of design patterns is to design for change. Many design patterns leave some room for future changes and evolutions. The application of design patterns leads to adaptable software since the design pattern instances could be changed with minimal impact on other parts of the system. Such changes, called the evolution of a design pattern instance in this paper, typically involve the addition or removal of a group of model elements, such as classes, attributes, operations, and relationships. However, the possible evolutions of each design pattern are often not explicitly documented. Missing a part of the evolution process may result in inconsistent evolutions. In this paper, we present our approach to assist the evolution processes of design patterns by model transformation technology. We provide a formal foundation for our approach by defining the predicates that can be used to describe the properties of each design pattern, software system design, and design pattern evolutions. We also provide tool support to automate the evolution processes based on the Query, View, and Transformation standard. A case study of a large open-source software system is conducted to illustrate and evaluate our approach.

Alcohol intoxication at 0.06 and 0.10% blood alcohol concentration changes segmental body movement coordination

Alcohol intoxication is the cause of many falls requiring emergency care. The control of upright standing balance is complex and comprises contributions from several partly independent mechanisms like coordination, feedback and feedforward control and adaptation. Analysis of the segmental body movement coordination offers one option to detect the severity of balance problems. The study aims were (1) to investigate whether alcohol intoxication at 0.06 and 0.10% blood alcohol concentration (BAC) affected the segmental movement pattern under unperturbed and perturbed standing; (2) whether alcohol affected the ability for movement pattern adaptation; (3) whether one's own subjective feeling of drunkenness correlated to the movement pattern used. Twenty-five participants (13 women and 12 men, mean age 25.1 years) performed tests involving alcohol intoxication. Body movements were recorded at five locations (ankle, knee, hip, shoulder and head) during quiet standing and pseudorandom pulses of calf muscle vibration for 200 s with eyes closed or open. There was no significant effect of alcohol on the general movement pattern in unperturbed stance or on adaptation. However, when balance was repeatedly perturbed, knee movements became significantly less correlated to other body movements over time at 0.10% BAC and when visual information was unavailable, suggesting that the normal movement pattern could not be maintained for a longer period of time while under 0.10% BAC intoxication. Subjective feelings of drunkenness correlated often with a changed upper body movement pattern but less so with changed knee movements. Thus, an inability to relate drunkenness with changed knee movements may be a contributing factor to falls in addition to the direct effect of alcohol intoxication.

Annotation based parser generator

The paper presents innovative parser construction method and parser generator prototype which generates a computer language parser directly from a set of annotated classes in contrast to standard parser generators which specify concrete syntax of a computer language using BNF notation. A language with textual concrete syntax is defined upon the abstract syntax definition extended with annotations in the presented approach. Annotations define instances of concrete syntax patterns in a language. Abstract syntax of a language is inevitable input of the parser generator as well as language's concrete syntax pattern definitions. The process of parser implementation is presented on the concrete computer language - the Simple Arithmetic Language. The paper summarizes results of the studies of implemented parser generator and describes its role in the university courses.

A Matrix-Based Approach to Recovering Design Patterns

Design patterns describe good solutions to common and recurring problems in software design. They have been widely applied in many software systems in industry. However, pattern-related information is typically not available in large system implementations. Recovering these design pattern instances in software systems can help not only to understand the original design decisions and tradeoffs but also to change the systems with quality assurance. This paper presents our approach on recovering design patterns based on matrices and weights. We formally specify our methods to encode both the systems and the design patterns into matrices and weight. Our formal specification rigorously defines the structural, behavioral, and semantic analyses of our approach. A set of experiments on real-world systems is also carried out to evaluate our approach with analysis results.

Design pattern density defined

Design pattern density is a metric that measures how much of an object-oriented design can be understood and represented as instances of design patterns. Expert developers have long believed that a high design pattern density implies a high maturity of the design under inspection. This paper presents a quantifiable and observable definition of this metric. The metric is illustrated and qualitatively validated using four real-world case studies. We present several hypotheses of the metric's meaning and their implications, including the one about design maturity. We propose that the design pattern density of a maturing framework has a fixed point and we show that if software design patterns make learning frameworks easier, a framework's design pattern density is a measure of how much easier it will become.

A REVIEW OF DESIGN PATTERN MINING TECHNIQUES

The quality of a software system highly depends on its architectural design. High quality software systems typically apply expert design experience which has been captured as design patterns. As demonstrated solutions to recurring problems, design patterns help to reuse expert experience in software system design. They have been extensively applied in the industry. Mining the instances of design patterns from the source code of software systems can assist in the understanding of the systems and the process of re-engineering them. More importantly, it also helps to trace back to the original design decisions, which are typically missing in legacy systems. This paper presents a review on current techniques and tools for mining design patterns from source code or design of software systems. We classify different approaches and analyze their results in a comparative study. We also examine the disparity of the discovery results of different approaches and analyze possible reasons with some insight.

Efficient Discovery of Spatial Co-Location Patterns Using the iCPI-tree

With the rapid growth and extensive applications of the spatial dataset, it's getting more important to solve how to find spatial knowledge automatically from spatial datasets. Spatial co-location patterns represent the subsets of features whose instances are frequently located together in geographic space. It's difficult to discovery co-location patterns be- cause of the huge amount of data brought by the instances of spatial features. A large fraction of the computation time is devoted to identifying the table instances of co-location patterns. The essence of co-location patterns discovery and four co-location patterns mining algorithms proposed in recent years are analyzed, and a new join-less approach for co-location patterns mining, which based on a data structure----iCPI-tree (Improved Co-location Pattern Instance Tree), is proposed. The iCPI-tree is an improved version of the CPI-tree which materializes spatial neighbor relationships in order to acceler- ate the process of identifying co-location instances. This paper proves the correctness and completeness of the new ap- proach. Finally, an experimental evaluations using synthetic and real world datasets show that the algorithm is computa- tionally more efficient.

An approach to evaluate the topological significance of motifs and other patterns in regulatory networks

BackgroundThe identification of network motifs as statistically over-represented topological patterns has become one of the most promising topics in the analysis of complex networks. The main focus is commonly made on how they operate by means of their internal organization. Yet, their contribution to a network's global architecture is poorly understood. However, this requires switching from the abstract view of a topological pattern to the level of its instances. Here, we show how a recently proposed metric, the pairwise disconnectivity index, can be adapted to survey if and which kind of topological patterns and their instances are most important for sustaining the connectivity within a network.ResultsThe pairwise disconnectivity index of a pattern instance quantifies the dependency of the pairwise connections between vertices in a network on the presence of this pattern instance. Thereby, it particularly considers how the coherence between the unique constituents of a pattern instance relates to the rest of a network. We have applied the method exemplarily to the analysis of 3-vertex topological pattern instances in the transcription networks of a bacteria (E. coli), a unicellular eukaryote (S. cerevisiae) and higher eukaryotes (human, mouse, rat). We found that in these networks only very few pattern instances break lots of the pairwise connections between vertices upon the removal of an instance. Among them network motifs do not prevail. Rather, those patterns that are shared by the three networks exhibit a conspicuously enhanced pairwise disconnectivity index. Additionally, these are often located in close vicinity to each other or are even overlapping, since only a small number of genes are repeatedly present in most of them. Moreover, evidence has gathered that the importance of these pattern instances is due to synergistic rather than merely additive effects between their constituents.ConclusionA new method has been proposed that enables to evaluate the topological significance of various connected patterns in a regulatory network. Applying this method onto transcriptional networks of three largely distinct organisms we could prove that it is highly suitable to identify most important pattern instances, but that neither motifs nor any pattern in general appear to play a particularly important role per se. From the results obtained so far, we conclude that the pairwise disconnectivity index will most likely prove useful as well in identifying other (higher-order) pattern instances in transcriptional and other networks.

XSLT‐based evolutions and analyses of design patterns

AbstractDesign patterns document flexible designs that may evolve over time. Design pattern evolution typically involves the addition or removal of a group of modeling elements, such as classes, attributes, operations, and relationships. However, the possible evolutions of each design pattern are often not explicitly documented. Missing part of the evolution process may result in inconsistent evolution. Pattern instances may interact with each other making the evolution of design patterns more error‐prone. Undetected design errors and inconsistencies may cause failures of systems. In this paper, we propose a service‐oriented architecture for design pattern evolution and analysis based on two‐level transformations, thus making the possible evolutions of each design pattern explicit. In addition, we automate the evolution processes as XSLT transformations that can transform the unified modeling language (UML) model of a design pattern application into the evolved UML model of the pattern. Both the original and evolved UML models are represented in the XML Metadata Interchange format to facilitate the transformations. Furthermore, we check the consistency of the evolution results using the semantic web checker based on the Java Theorem Prover. A case study on a large real‐world system is presented to illustrate and evaluate our approach. Copyright © 2009 John Wiley & Sons, Ltd.

Codeswitching in Bilingual Children with Specific Language Impairment.

Children with specific language impairment (SLI) exhibit limited grammatical skills compared to their peers with typical language. These difficulties may be revealed when alternating their two languages (i.e., codeswitching) within sentences. Fifty-eight Spanish-English speaking children with and without SLI produced narratives using wordless picture books and conversational samples. The results indicated no significant differences in the proportion of utterances with codeswitching (CS) across age groups or contexts of elicitation. There were significant effects for language dominance, language of testing, and a significant dominance by language of testing interaction. The English-dominant children demonstrated more CS when tested in their nondominant language (Spanish) compared to the Spanish-dominant children tested in their weaker English. The children with SLI did not display more CS or more instances of atypical CS patterns compared to their typical peers. The findings indicate that children with SLI are capable of using grammatical CS, in spite of their language difficulties. In addition, the analyses suggest that CS is sensitive to sociolinguistic variables such as when the home language is not socially supported in the larger sociocultural context. In these cases, children may refrain from switching to the home language, even if that is their dominant language.

Design pattern recovery through visual language parsing and source code analysis

In this paper we propose an approach for recovering structural design patterns from object-oriented source code. The recovery process is organized in two phases. In the first phase, the design pattern instances are identified at a coarse-grained level by considering the design structure only and exploiting a parsing technique used for visual language recognition. Then, the identified candidate patterns are validated by a fine-grained source code analysis phase. The recognition process is supported by a tool, namely design pattern recovery environment, which allowed us to assess the retrieval effectiveness of the proposed approach on six public-domain programs and libraries.

MetaMine--a tool to detect and analyse gene patterns in their environmental context.

BackgroundModern sequencing technologies allow rapid sequencing and bioinformatic analysis of genomes and metagenomes. With every new sequencing project a vast number of new proteins become available with many genes remaining functionally unclassified based on evidences from sequence similarities alone. Extending similarity searches with gene pattern approaches, defined as genes sharing a distinct genomic neighbourhood, have shown to significantly improve the number of functional assignments. Further functional evidences can be gained by correlating these gene patterns with prevailing environmental parameters. MetaMine was developed to approach the large pool of unclassified proteins by searching for recurrent gene patterns across habitats based on key genes.ResultsMetaMine is an interactive data mining tool which enables the detection of gene patterns in an environmental context. The gene pattern search starts with a user defined environmentally interesting key gene. With this gene a BLAST search is carried out against the Microbial Ecological Genomics DataBase (MEGDB) containing marine genomic and metagenomic sequences. This is followed by the determination of all neighbouring genes within a given distance and a search for functionally equivalent genes. In the final step a set of common genes present in a defined number of distinct genomes is determined. The gene patterns found are associated with their individual pattern instances describing gene order and directions. They are presented together with information about the sample and the habitat. MetaMine is implemented in Java and provided as a client/server application with a user-friendly graphical user interface. The system was evaluated with environmentally relevant genes related to the methane-cycle and carbon monoxide oxidation.ConclusionMetaMine offers a targeted, semi-automatic search for gene patterns based on expert input. The graphical user interface of MetaMine provides a user-friendly overview of the computed gene patterns for further inspection in an ecological context. Prevailing biological processes associated with a key gene can be used to infer new annotations and shape hypotheses to guide further analyses. The use-cases demonstrate that meaningful gene patterns can be quickly detected using MetaMine.MetaMine is freely available for academic use from .

Who's the Fairest of them All? An Empirical Test for Partisan Bias on ABC, CBS, NBC, and Fox News

While accusations of media bias have long been a staple of partisan discourse, a number of issues have generally undermined their scholarly validity. While some have unearthed specific instances of biased story construction or patterns of bias in news content, these examples tend to be undermined by the inherent subjectivity of defining “bad” news. Moreover, these studies are generally unable to test for selection bias because they cannot observe the characteristics of stories that were not selected for broadcast. This study is designed to overcome these problems and allow for a more comprehensive test for detecting bias in television news. In particular, this study examines coverage of presidential approval polls on Fox News's flagship news program, Special Report, as well as on ABC's, CBS's, and NBC's evening newscasts over the last decade. The results provide substantial evidence for bias in the news choices across the four news outlets, although somewhat surprisingly, the results are stronger for some of the networks than for Fox.

MINING FREQUENT TEMPORAL PATTERNS IN INTERVAL SEQUENCES

Recently a new type of data source came into the focus of knowledge discovery from temporal data: interval sequences. In contrast to event sequences, interval sequences contain labeled events with a temporal extension. However, existing algorithms for mining patterns from interval sequences proved to be far from satisfying our needs. In brief, we missed an approach that, at the same time, defines support as the number of pattern instances, allows input data that consists of more than one sequence, implements time constraints on a pattern instance, and counts multiple instances of a pattern within one interval sequence. In this paper we propose a new support definition which incorporates these properties. We also describe FSMSet, an algorithm that employs the new support definition, and demonstrate its performance on field data from the automotive business.

Toward an understanding of bug fix patterns

Twenty-seven automatically extractable bug fix patterns are defined using the syntax components and context of the source code involved in bug fix changes. Bug fix patterns are extracted from the configuration management repositories of seven open source projects, all written in Java (Eclipse, Columba, JEdit, Scarab, ArgoUML, Lucene, and MegaMek). Defined bug fix patterns cover 45.7% to 63.3% of the total bug fix hunk pairs in these projects. The frequency of occurrence of each bug fix pattern is computed across all projects. The most common individual patterns are MC-DAP (method call with different actual parameter values) at 14.9---25.5%, IF-CC (change in if conditional) at 5.6---18.6%, and AS-CE (change of assignment expression) at 6.0---14.2%. A correlation analysis on the extracted pattern instances on the seven projects shows that six have very similar bug fix pattern frequencies. Analysis of if conditional bug fix sub-patterns shows a trend towards increasing conditional complexity in if conditional fixes. Analysis of five developers in the Eclipse projects shows overall consistency with project-level bug fix pattern frequencies, as well as distinct variations among developers in their rates of producing various bug patterns. Overall, data in the paper suggest that developers have difficulty with specific code situations at surprisingly consistent rates. There appear to be broad mechanisms causing the injection of bugs that are largely independent of the type of software being produced.