Ontology modularization: principles and practice

Technological advances have provided us with the capability to build large intelligent systems capable of using knowledge, which relies on being able to represent the knowledge in a way that machines can process and interpret. This is achieved by using ontologies; that is logical theories that capture the knowledge of a domain. It is widely accepted that ontology development is a non-trivial task and can be expedited through the reuse of existing ontologies. However, it is likely that the developer would only require a part of the original ontology; obtaining this part is the purpose of ontology modularization. In this thesis a graph traversal based technique for performing ontology module extraction is presented. We present an extensive evaluation of the various ontology modularization techniques in the literature; including a proposal for an entropy inspired measure. A task-based evaluation is included, which demonstrates that traversal based ontology module extraction techniques have comparable performance to the logical based techniques. Agents, autonomous software components, use ontologies in complex systems; with each agent having its own, possibly different, ontology. In such systems agents need to communicate and successful communication relies on the agents ability to reach an agreement on the terms they will use to communicate. Ontology modularization allows the agents to agree on only those terms relevant to the purpose of the communication. Thus, this thesis presents a novel application of ontology modularization as a space reduction mechanism for the dynamic selection of ontology alignments in multi-agent systems. The evaluation of this novel application shows that ontology modularization can reduce the search space without adversely affecting the quality of the agreed ontology alignment

Empowering End-users to Collaboratively Manage and Analyze Evolving Data Models

In order to empower end-users to make well-founded decisions based on domain-specific knowledge, companies use end-user oriented business intelligence (BI) software like spreadsheets. Moreover, many decisions require the collaboration of multiple and autonomous knowledge workers. However, prevalent BI software does not provide elevated collaboration features as known from traditional Web 2.0 technologies. There is also a lack of research on how to integrate collaboration features into BI systems, and which challenges arise as a consequence. In the paper at hand we address this issue by proposing the Spreadsheet 2.0 approach, which integrates Web 2.0 features with the spreadsheet paradigm as most-common representative of end-user-oriented business intelligence tools. Therefore, we derive requirements for a Web 2.0-based approach to collaborative BI, and present the conceptual design for a Spreadsheet 2.0 solution. Subsequently, we demonstrate a corresponding prototypical implementation, and elaborate on key findings and main challenges identified by its application and evaluation

A Quantitative Approach to Assessing System Evolvability

When selecting a system from multiple candidates, the customer seeks the one that best meets his or her needs. Recently the desire for evolvable systems has become more important and engineers are striving to develop systems that accommodate this need. In response to this search for evolvability, we present a historical perspective on evolvability, propose a refined definition of evolvability, and develop a quantitative method for measuring this property. We address this quantitative methodology from both a theoretical and practical perspective. This quantitative model is then applied to the problem of evolving a lunar mission to a Mars mission as a case study

Workflow Provenance: from Modeling to Reporting

Workflow provenance is a crucial part of a workflow system as it enables data lineage analysis, error tracking, workflow monitoring, usage pattern discovery, and so on. Integrating provenance into a workflow system or modifying a workflow system to capture or analyze different provenance information is burdensome, requiring extensive development because provenance mechanisms rely heavily on the modelling, architecture, and design of the workflow system. Various tools and technologies exist for logging events in a software system. Unfortunately, logging tools and technologies are not designed for capturing and analyzing provenance information. Workflow provenance is not only about logging, but also about retrieving workflow related information from logs. In this work, we propose a taxonomy of provenance questions and guided by these questions, we created a workflow programming model 'ProvMod' with a supporting run-time library to provide automated provenance and log analysis for any workflow system. The design and provenance mechanism of ProvMod is based on recommendations from prominent research and is easy to integrate into any workflow system. ProvMod offers Neo4j graph database support to manage semi-structured heterogeneous JSON logs. The log structure is adaptable to any NoSQL technology. For each provenance question in our taxonomy, ProvMod provides the answer with data visualization using Neo4j and the ELK Stack. Besides analyzing performance from various angles, we demonstrate the ease of integration by integrating ProvMod with Apache Taverna and evaluate ProvMod usability by engaging users. Finally, we present two Software Engineering research cases (clone detection and architecture extraction) where our proposed model ProvMod and provenance questions taxonomy can be applied to discover meaningful insights

AVOIDIT IRS: An Issue Resolution System To Resolve Cyber Attacks

Cyber attacks have greatly increased over the years and the attackers have progressively improved in devising attacks against specific targets. Cyber attacks are considered a malicious activity launched against networks to gain unauthorized access causing modification, destruction, or even deletion of data. This dissertation highlights the need to assist defenders with identifying and defending against cyber attacks. In this dissertation an attack issue resolution system is developed called AVOIDIT IRS (AIRS). AVOIDIT IRS is based on the attack taxonomy AVOIDIT (Attack Vector, Operational Impact, Defense, Information Impact, and Target). Attacks are collected by AIRS and classified into their respective category using AVOIDIT.Accordingly, an organizational cyber attack ontology was developed using feedback from security professionals to improve the communication and reusability amongst cyber security stakeholders. AIRS is developed as a semi-autonomous application that extracts unstructured external and internal attack data to classify attacks in sequential form. In doing so, we designed and implemented a frequent pattern and sequential classification algorithm associated with the five classifications in AVOIDIT. The issue resolution approach uses inference to educate the defender on the plausible cyber attacks. The AIRS can work in conjunction with an intrusion detection system (IDS) to provide a heuristic to cyber security breaches within an organization. AVOIDIT provides a framework for classifying appropriate attack information, which is fundamental in devising defense strategies against such cyber attacks. The AIRS is further used as a knowledge base in a game inspired defense architecture to promote game model selection upon attack identification. Future work will incorporate honeypot attack information to improve attack identification, classification, and defense propagation.In this dissertation, 1,025 common vulnerabilities and exposures (CVEs) and over 5,000 lines of log files instances were captured in the AIRS for analysis. Security experts were consulted to create rules to extract pertinent information and algorithms to correlate identified data for notification. The AIRS was developed using the Codeigniter [74] framework to provide a seamless visualization tool for data mining regarding potential cyber attacks relative to web applications. Testing of the AVOIDIT IRS revealed a recall of 88%, precision of 93%, and a 66% correlation metric