Thomas Trojer

Service-Oriented Architecture for High-Dimensional Private Data Mashup

Mashup is a web technology that allows different service providers to flexibly integrate their expertise and to deliver highly customizable services to their customers. Data mashup is a special type of mashup application that aims at integrating data from multiple data providers depending on the users request. However, integrating data from multiple sources brings about three challenges: 1) Simply joining multiple private data sets together would reveal the sensitive information to the other data providers. 2) The integrated (mashup) data could potentially sharpen the identification of individuals and, therefore, reveal their person-specific sensitive information that was not available before the mashup. 3) The mashup data from multiple sources often contain many data attributes. When enforcing a traditional privacy model, such as K-anonymity, the high-dimensional data would suffer from the problem known as the curse of high dimensionality, resulting in useless data for further data analysis. In this paper, we study and resolve a privacy problem in a real-life mashup application for the online advertising industry in social networks, and propose a service-oriented architecture along with a privacy-preserving data mashup algorithm to address the aforementioned challenges. Experiments on real-life data suggest that our proposed architecture and algorithm is effective for simultaneously preserving both privacy and information utility on the mashup data. To the best of our knowledge, this is the first work that integrates high-dimensional data for mashup service.

Living Modeling of IT Architectures: Challenges and Solutions

Enterprise Architecture Models (EA Models) are documentations capturing the elements of an enterprise’s IT infrastructure, setting these elements in relation to each other and setting them into the context of the business. EA Models are a crucial backbone for any IT management process and activities like analysing IT related risks and planning investments. The more companies depend on reliable IT services and use IT as innovation driver, the more high quality EA Models provide competitive advantage. In this paper we describe core challenges to the maintenance of EA Models based on previously conducted surveys and our longstanding experience in industrial collaborations. This is followed by a sketch of an innovative solution to solve these challenges.

Service-Oriented Architecture for Privacy-Preserving Data Mashup

Mashup is a web technology that combines information from more than one source into a single web application.This technique provides a new platform for different data providers to flexibly integrate their expertise and deliver highly customizable services to their customers. None the-less, combining data from different sources could potentially reveal person-specific sensitive information. In this paper, we study and resolve a real-life privacy problem in a data mashup application for the financial industry in Swe-den. Therefore we propose a service-oriented architecture for privacy-preserving data mashup together with a multi-party protocol to securely integrate private data from different data providers, whereas the integrated data still retains the essential information for supporting general data exploration or a specific data mining task, such as classification analysis. Experiments on real-life data suggest that our proposed method is effective for simultaneously preserving both privacy and information usefulness.

Gateway to Quality Living for the Elderly: Charting an Innovative Approach to Evidence-Based E-Health Technologies for Serving the Chronically Ill

In this paper, we explore four critical barriers to e-Health effectiveness and discuss why and how to build and evaluate e-Health technologies for the chronically ill, including: (1) gaps in knowledge about learning and health behaviors, (2) metrics for technology adoption and beneficial use, (3) sampling and decision support, and (4) adherence and adaptive care customization. Accordingly, the metaphor of a “gateway” is used to imply that healthcare providers and the individuals they serve must engage in a sensible two-way interactions, on the one hand, it should open the door for providers to offer personalized and cost-effective care, on the other hand, it should also open the door to a welcoming environment that provides easy access and motivation for sustained use by the chronically-ill individuals.

A Case Study on Textual Enterprise Architecture Modeling

Todays Enterprise Architecture Management (EAM) tools are based on forms and graphical modeling capabilities via web-based applications or desktop clients. However, recent developments in textual modeling tools have not yet been considered for EA modeling in research and practice. In this paper we present a novel EAM-tool approach, called Txture, that consists of a textual modeling environment and a web-application to provide enterprise-wide architecture visualizations for different stakeholder groups. The tool is in production use at a major Austrian data center, where it proofed to be intuitive and provide efficient modeling capabilities compared to traditional approaches. In this paper we present lessons learned from the development of the tool as well as usage it and report on its benefits and drawbacks.

The Process of Policy Authoring of Patient-Controlled Privacy Preferences.

Discussions about appropriate security controls to protect medical records led to the understanding that the patient her-/himself plays a crucial role in networked electronic health-care. Patients have individual privacy concerns and may want to execute their personal right of self-determination on access and usage of their medical records. The ability for patients to have control over their personal medical data is the essence of patient-centric networked electronic health-care, but poses challenges regarding its tool support. Since patients can be generally treated as non-security experts as well as non-health-care domain experts, usability-supporting factors of authoring tools for privacy preferences have to receive major attention by implementers. Additionally, domain characteristics have to influence the design of such authoring applications. Finally expressed privacy preferences have to be analysed to inform the patient-author and guide her/him in the policy authoring process. In this paper we discuss the process of authorization policy authoring for shared electronic health records which we use to implement patient-controlled access control authoring tools. Further a use-case in the context of a specific health-care infrastructure is presented.

An Authoring Framework for Security Policies: A Use-Case within the Healthcare Domain

Traditionally, the definition and the maintenance of security and access control policies has been the exclusive task of system administrators or security officers. In modern distributed and heterogeneous systems, there exist the need to allow different stakeholders to create and edit their security and access control preferences. In order to solve this problem two main challenges need to be met. First, authoring tools with different user interfaces should be designed and adapted to meet domain background and the degree of expertise of each stakeholder. For example, policy authoring tools for a patient or a doctor should be user friendly and not contain any technical details, while those for a security administrators can be more sophisticated, containing more details. Second, conflicts that can arise among security policies defined by different stakeholders must be considered by these authoring tools on runtime. Furthermore, warnings and assisting messages must be provided to help defining correct policies and to avoid potential security risks. Towards meeting these challenges, we propose an authoring framework for security policies. This framework enables building authoring tools that take into consideration the views of different stakeholders.

ChronoGraph - Versioning Support for OLTP TinkerPop Graphs.

In recent years, techniques for system-time versioning of database content are becoming more sophisticated and powerful, due to the demands of business-critical applications that require traceability of changes, auditing capabilities or historical data analysis. The essence of these techniques was standardized in 2011 when it was introduced as a part of the SQL standard. However, in NoSQL databases and in particular in the emerging graph technologies, these aspects are so far being neglected by database providers. In this paper, we present ChronoGrapha, the first TinkerPop graph database implementation that offers comprehensive support for content versioning and analysis, designed for Online Transaction Processing (OLTP). This paper offers two key contributions: the addition of our novel versioning concepts to the state of the art in graph databases, as well as their implementation as an open-source project. We demonstrate the feasibility of our proposed solution through controlled experiments. aThis work was partially funded by the research project “txtureSA” (FWF-Project P 29022).

Factors of Access Control Management in Electronic Healthcare: The Patients' Perspective

Information systems in electronic healthcare have the potential to support a variety of medical stakeholders in performing their regular daily working activities. Still with the growing amount of electronically available health-related data on patients, aspects of data privacy have to be considered, e.g., by improving the transparency of healthcare processes or by offering methods to allow patients to self-determine controls for their data. In this work we present the results of a study we conducted in Austria about the general desire of patients to self-control access to their health records as well as to elicit typical factors for access control they personally consider as important. The results we present in this work are intended to support the requirements analysis and development of patient-centric healthcare management applications. As our results clearly indicate that patients have varying conceptions regarding privacy we also elaborate on the proper integration of access control factors to satisfy individual informational requirements.

Combining Versioning and Metamodel Evolution in the ChronoSphere Model Repository

Model Driven Engineering (MDE) has gained a lot of popularity in recent years and is being applied in a wide variety of domains. As teams, models and applications grow in size, the need for faster and more scalable technology emerges, in particular in the crucial area of model repositories. These software components are responsible for persisting, querying and versioning the model content and act as central hubs for interaction with the model. However, existing repository solutions do not consider metamodel evolution, which is important in long-running projects. In this paper, we present ChronoSphere, a novel model repository, targeted specifically towards developers working with MDE technology in industry, with a focus on models-at-runtime scenarios. By utilizing the latest innovations in graph databases and version control, ChronoSphere provides transparent and efficient versioning as well as metamodel evolution capabilities. This paper focuses on the core concepts of ChronoSphere, in particular data management, versioning and metamodel evolution. Our open-source implementation serves as proof of concept.