A cooperative framework for integrating ontologies

Nowadays, there are systems and frameworks that support Ontology construction processes. However, ontology integration processes have not sufficiently been specified to date. In this article, by making use of a cooperative philosophy, we describe a real framework for the integration of ontologies supplied by a predetermined set of (expert) users, who may be interconnected through a communication network. This framework is based on a set of well-defined assumptions that guarantee the consistency of the ontology derived from the ontology integration process. Moreover, in the approach presented here, every (expert) user may consult the so-derived ontology constructed until a given moment in order to refine his or her private ontology. In addition to this, the model proposed in this work allows the experts involved in the construction of the ontology to use their own terminology when querying the global ontology obtained until a given instant from their own co-operative work. The validation of the framework is also included in this work.     

FacetCube: a general framework for non-negative tensor factorization

Non-negative tensor factorization (NTF) has been successfully used to extract significant characteristics from polyadic data, such as data in social networks. Because these polyadic data have multiple dimensions (e.g., the author, content, and timestamp of a blog post), NTF fits in naturally and extracts data characteristics jointly from different data dimensions. In the traditional NTF, all information comes from the observed data, and therefore, the end users have no control over the outcomes. However, in many applications very often, the end users have certain prior knowledge, such as the demographic information about individuals in a social network or a pre-constructed ontology on the contents and therefore prefer the data characteristics extracting by NTF being consistent with such prior knowledge. To allow users’ prior knowledge to be naturally incorporated into NTF, in this paper, we present a general framework—FacetCube—that extends the standard NTF. The new framework allows the end users to control the factorization outputs at three different levels for each of the data dimensions. The proposed framework is intuitively appealing in that it has a close connection to the probabilistic generative models. In addition to introducing the framework, we provide an iterative algorithm for computing the optimal solution to the framework. We also develop an efficient implementation of the algorithm that consists of several techniques to make our framework scalable to large data sets. Extensive experimental studies on a paper citation data set and a blog data set demonstrate that our new framework is able to effectively incorporate users’ prior knowledge, improves performance over the traditional NTF on the task of personalized recommendation, and is scalable to large data sets from real-life applications.     

Ontology-based multiperspective requirements traceability framework

Large-scaled software development inevitably involves a group of stakeholders, each of whom may express their requirements differently in their own terminology and representation depending on their perspectives or perceptions of their shared problems. In view of that, the heterogeneity must be well handled and resolved in tracing and managing changes of such requirements. This paper presents our multiperspective requirements traceability (MUPRET) framework which deploys ontology as a knowledge management mechanism to intervene mutual “understanding” without restricting the freedom in expressing requirements differently. Ontology matching is applied as a reasoning mechanism in automatically generating traceability relationships. The relationships are identified by deriving semantic analogy of ontology concepts representing requirements elements. The precision and recall of traceability relationships generated by the framework are verified by comparing with a set of traceability relationships manually identified by users as a proof-of-concept of this framework.     

Ontology Evolution: Not the Same as Schema Evolution

As ontology development becomes a more ubiquitous and collaborative process, ontology versioning and evolution becomes an important area of ontology research. The many similarities between database-schema evolution and ontology evolution will allow us to build on the extensive research in schema evolution. However, there are also important differences between database schemas and ontologies. The differences stem from different usage paradigms, the presence of explicit semantics and different knowledge models. A lot of problems that existed only in theory in database research come to the forefront as practical problems in ontology evolution. These differences have important implications for the development of ontology-evolution frameworks: The traditional distinction between versioning and evolution is not applicable to ontologies. There are several dimensions along which compatibility between versions must be considered. The set of change operations for ontologies is different. We must develop automatic techniques for finding similarities and differences between versions.     

MINI——一种可减小变更影响范围的本体演化算法

本体演化会影响依赖本体的服务,使其重新修订和重新部署.面对同一变更需求,不同演化实现方法造成的影响范围差别很大.当前的本体演化研究主要集中在如何实现变更需求以及维护变更前后本体的一致性,对于如何降低演化影响范围关注甚少.文中提出了一种可以有效减小变更影响范围的本体演化算法MINI.该算法首先分析了本体实体和服务之间的依赖关系并提出了量化变更影响范围的数学公式.根据这一公式,MINI算法将本体演化过程转变为图的启发式搜索过程,通过搜索一条影响值最小的变更路径来减小本体演化的影响范围.实验结果表明,MINI算法导致的平均变更影响范围大大小于现有的本体演化算法.该算法已在某实际项目中得以应用和验证.     

本体映射的进化研究

本体映射的进化是本体研究中待研究的课题之一。本文首先给出本体和本体映射形式化定义,在此基础上讨论本体变化后的映射进化方法。将本体变化类型分为删除、增加、修改,针对不同的类型提出本体删除后的映射进化算法、本体增加后的映射进化算法和本体修改后的映射进化算法。实验结果表明该方法能基本解决本体映射的进化问题。最后指出算法中存在的挑战,并给出进一步研究的方向。     

面向领域知识的本体知识模型XML表示框架

基于面向领域知识表示模型的共性与差异，提出了一种基于本体的领域知识XML表示框架模型。首先，给出了关于本体及知识建模的相关定义，并对领域知识进行了简单定义及分析；在此基础上，给出了面向领域知识的本体知识模型的XML表示框架，对领域知识建模从领域模式和领域知识库两个方面进行了建模研究，实现了组成领域知识模型框架的两个子框架模型。     

本体演化管理研究

自W3C主席TimBerncrs-Lee首先提出了语义web的概念后,它正在成为计算机信息处理领域当前研究的热点之一。本体将在“语义Web”中起到至关重要的作用,它通过定义精确的共享术语,以提供某一特定领域可重用的知识。但是这些知识并不是静态的,而是随着时问的推移不断演化。领域的改变、自适应不同的任务、或概念模型的改变都要求本体的变更。随着本体开发变成一个泛化的、协同的过程,本体版本控制和演化管理已成为本体研完中一个重要的领域。本文首先对本体演化的原因和所带来的问题进行分析,然后讨论了本体演化管理的关键技术,着重强调了Web上本体标识和本体变化机制的定义,并对今后的研究工作进行了展望。     

A Flexible Ontology Reasoning Architecture for the Semantic Web

Knowledge-based systems in the semantic Web era can make use of the power of the semantic Web languages and technologies, in particular those related to ontologies. Recent research has shown that user-defined data types are very useful for semantic Web and ontology applications. The W3C semantic Web best practices and development working group has set up a task force to address this issue. Very recently, OWL-Eu and OWL-E, two decidable extensions of the W3C standard ontology language OWL DL, have been proposed to support customized data types and customized data type predicates, respectively. In this paper, we propose a flexible reasoning architecture for these two expressive semantic Web ontology languages and describe our prototype implementation of the reasoning architecture, based on the well-known FaCT DL reasoner, which witnesses the two key flexibility features of our proposed architecture: 1) It allows users to define their own data types and data type predicates based on built-in ones and 2) new data type reasoners can be added into the architecture without having to change the concept reasoner     

Exploring how users engage with hybrid process artifacts based on declarative process models: a behavioral analysis based on eye-tracking and think-aloud

Process design artifacts have been increasingly used to guide the modeling of business processes. To support users in designing and understanding process models, different process artifacts have been combined in several ways leading to the emergence of the so-called “hybrid process artifacts”. While many hybrid artifacts have been proposed in the literature, little is known about how they can actually support users in practice. To address this gap, this work investigates the way users engage with hybrid process artifacts during comprehension tasks. In particular, we focus on a hybrid representation of DCR Graphs (DCR-HR) combining a process model, textual annotations and an interactive simulation. Following a qualitative approach, we conduct a multi-granular analysis exploiting process mining, eye-tracking techniques, and verbal data analysis to scrutinize the reading patterns and the strategies adopted by users when being confronted with DCR-HR. The findings of the coarse-grained analysis provide important insights about the behavior of domain experts and IT specialists and show how user’s background and task type change the use of hybrid process artifacts. As for the fine-grained analysis, user’s behavior was classified into goal-directed and exploratory and different strategies of using the interactive simulation were identified. In addition, a progressive switch from an exploratory behavior to a goal-directed behavior was observed. These insights pave the way for an improved development of hybrid process artifacts and delineate several directions for future work.

     

A comprehensive framework for the evaluation of ontology modularization

The Semantic Web and ontologies have received increased attention in recent years. The delivery of well-designed ontologies enhances the effect of Semantic Web services, but building ontologies from scratch requires considerable time and effort. Modularizing ontologies and integrating ontology modules to a given context help users effectively develop ontologies and revitalize ontology dissemination. Therefore, various tools for modularizing ontologies have been developed. However, selecting an appropriate tool to fit a given context is difficult because the assumptions for the approaches greatly vary. Therefore, a suitable framework is required to compare and help screen the most suitable modularization tool.In this research, we propose a new evaluation framework for selecting an appropriate ontology modularization tool. We present three aspects of tool evaluation as the main dimensions for the assessment of modularization tools: tool performance, data performance, and usability.This study provides an implicit evaluation and an empirical analysis of three modularization tools. It also provides an evaluation method for ontology modularization, enabling ontology engineers to compare different modularization tools and easily choose an appropriate one for the production of qualifying ontology modules.The experimental results indicate that the proposed evaluation criteria for ontology modularization tools are valid and effective. This research provides a useful method for assessing and selecting ontology modularization tools. Modularization performance, data performance, and usability are the three modularization aspects designed and applied to the context of ontology. We provide a new focus on the comprehensive framework to evaluate the performance and usability of ontology modularization tools. The proposed framework should be of value to both ontology engineers, who are interested in ontology modularization, and to practitioners, who need information on how to evaluate and select a specific type of ontology tool in accordance with the requirements of the individual environment.     

流程可定制本体匹配框架:RiMOM2

本体作为语义Web中的语义表示形式,是语义Web体系结构中的核心元素,是实现知识共享、协同工作的关键。然而现实世界中本体自身与生俱来的分布性和异构性,又极大地限制了数据的共享与集成。为了实现知识的共享、数据的集成,近年来针对本体匹配方法的研究得到了广泛的重视。随着本体匹配研究的深入,许多有效的本体匹配方法被提出。RiMOM2正是一种集成了多种有效本体匹配方法的多策略本体匹配框架。它尽可能地向初级用户隐藏不必要的阂值设定和参数设置,而向高级用户提供匹配流程的可定制功能,以期针对不同用户实现一种既能适用于普遍本体匹配任务,操作简易,又能达到具有针对性匹配效果的本体匹配工具。同时该框架具有匹配方法组件的易扩展性。     

Knowledge graph embeddings for dealing with concept drift in machine learning

Data stream learning has been largely studied for extracting knowledge structures from continuous and rapid data records. As data is evolving on a temporal basis, its underlying knowledge is subject to many challenges. Concept drift,¹ as one of core challenge from the stream learning community, is described as changes of statistical properties of the data over time, causing most of machine learning models to be less accurate as changes over time are in unforeseen ways. This is particularly problematic as the evolution of data could derive to dramatic change in knowledge. We address this problem by studying the semantic representation of data streams in the Semantic Web, i.e., ontology streams. Such streams are ordered sequences of data annotated with ontological vocabulary. In particular we exploit three levels of knowledge encoded in ontology streams to deal with concept drifts: i) existence of novel knowledge gained from stream dynamics, ii) significance of knowledge change and evolution, and iii) (in)consistency of knowledge evolution. Such knowledge is encoded as knowledge graph embeddings through a combination of novel representations: entailment vectors, entailment weights, and a consistency vector. We illustrate our approach on classification tasks of supervised learning. Key contributions of the study include: (i) an effective knowledge graph embedding approach for stream ontologies, and (ii) a generic consistent prediction framework with integrated knowledge graph embeddings for dealing with concept drifts. The experiments have shown that our approach provides accurate predictions towards air quality in Beijing and bus delay in Dublin with real world ontology streams.     

Coevolution of variability models and related software artifacts

Variant-rich software systems offer a large degree of customization, allowing users to configure the target system according to their preferences and needs. Facing high degrees of variability, these systems often employ variability models to explicitly capture user-configurable features (e.g., systems options) and the constraints they impose. The explicit representation of features allows them to be referenced in different variation points across different artifacts, enabling the latter to vary according to specific feature selections. In such settings, the evolution of variability models interplays with the evolution of related artifacts, requiring the two to evolve together, or coevolve. Interestingly, little is known about how such coevolution occurs in real-world systems, as existing research has focused mostly on variability evolution as it happens in variability models only. Furthermore, existing techniques supporting variability evolution are usually validated with randomly-generated variability models or evolution scenarios that do not stem from practice. As the community lacks a deep understanding of how variability evolution occurs in real-world systems and how it relates to the evolution of different kinds of software artifacts, it is not surprising that industry reports existing tools and solutions ineffective, as they do not handle the complexity found in practice. Attempting to mitigate this overall lack of knowledge and to support tool builders with insights on how variability models coevolve with other artifact types, we study a large and complex real-world variant-rich software system: the Linux kernel. Specifically, we extract variability-coevolution patterns capturing changes in the variability model of the Linux kernel with subsequent changes in Makefiles and C source code. From the analysis of the patterns, we report on findings concerning evolution principles found in the kernel, and we reveal deficiencies in existing tools and theory when handling changes captured by our patterns.     

一种支持可靠语义互操作的本体演化管理框架

准确描述本体之间的关联是保证信息系统语义互操作可靠性的关键。该文提出了一个本体演化管理框架MFI-3，它包括本体注册模型、变化模型、约束模型、演化信息模型和变化传播模型。这些模型能支持本体的基本内容注册、本体复用及复杂的演化。通过对基于本框架的本体演化信息进行计算，可以得到可靠的本体映射。     

Nested Tracking Graphs

Tracking graphs are a well established tool in topological analysis to visualize the evolution of components and their properties over time, i.e., when components appear, disappear, merge, and split. However, tracking graphs are limited to a single level threshold and the graphs may vary substantially even under small changes to the threshold. To examine the evolution of features for varying levels, users have to compare multiple tracking graphs without a direct visual link between them. We propose a novel, interactive, nested graph visualization based on the fact that the tracked superlevel set components for different levels are related to each other through their nesting hierarchy. This approach allows us to set multiple tracking graphs in context to each other and enables users to effectively follow the evolution of components for different levels simultaneously. We demonstrate the effectiveness of our approach on datasets from finite pointset methods, computational fluid dynamics, and cosmology simulations.     

Impact analysis of ERP post-implementation modifications: Design,tool support and evaluation

ERP systems evolve in the post-implementation phase because of changing business requirements. Post-implementation changes are likely to decrease the quality of ERP systems and of the data that they use, which negatively impacts organisational performance. We propose a framework for impact analysis of ERP post-implementation modifications. Our framework allows mapping dependencies among ERP system components and, based on these dependencies, automatically assessing the impact of a proposed change on both the design-time structure and run-time landscape of the system through a novel set of impact metrics. The framework also provides semi-automatic support to safely terminating the running process instances affected by change. The framework is evaluated with expert users in two pseudo-real ERP system implementations.     

An ontology-driven framework towards building enterprise semantic information layer

Enterprises Information Systems (EIS) have been applied for decades in Computer-Aided Engineering (CAE) and Computer-Aided Design (CAD), where huge amount of increasing data is stored in the heterogeneous and distributed systems. As systems evaluating, system redesign and reengineering are demanded. A facing challenge is how to interoperate among different systems by overcoming the gap of conceptual heterogeneity. In this article, an enlarged data representation called semantic information layer (SIL) is described for facilitating heterogeneous systems interoperable. SIL plays a role as mediation media and knowledge representation among heterogeneous systems. The SIL building process is based on ontology engineering, including ontology extraction from relational database (RDB), ontology enrichment and ontology alignment. Mapping path will maintain the links between SIL and data source, and query implementation and user interface are for retrieving data and interacting with end users. We described fully a practical ontology-driven framework for building SIL and introduced extensively relevant standards and techniques for implementing the framework. In the core part of ontology development, a dynamic multi-strategies ontology alignment with automatic matcher selection and dynamic similarity aggregation is proposed. A demonstration case study in the scenario of mobile phone industry is used to illustrate the proposed framework.     

SEON: a pyramid of ontologies for software evolution and its applications

The Semantic Web provides a standardized, well-established framework to define and work with ontologies. It is especially apt for machine processing. However, researchers in the field of software evolution have not really taken advantage of that so far. In this paper, we address the potential of representing software evolution knowledge with ontologies and Semantic Web technology, such as Linked Data and automated reasoning. We present Seon, a pyramid of ontologies for software evolution, which describes stakeholders, their activities, artifacts they create, and the relations among all of them. We show the use of evolution-specific ontologies for establishing a shared taxonomy of software analysis services, for defining extensible meta-models, for explicitly describing relationships among artifacts, and for linking data such as code structures, issues (change requests), bugs, and basically any changes made to a system over time. For validation, we discuss three different approaches, which are backed by Seon and enable semantically enriched software evolution analysis. These techniques have been fully implemented as tools and cover software analysis with web services, a natural language query interface for developers, and large-scale software visualization.