Ulrik Franke

CYBER SITUATIONAL AWARENESS – A SYSTEMATIC REVIEW OF THE LITERATURE

Abstract Cyber situational awareness is attracting much attention. It features prominently in the national cyber strategies of many countries, and there is a considerable body of research dealing with it. However, until now, there has been no systematic and up-to-date review of the scientific literature on cyber situational awareness. This article presents a review of cyber situational awareness, based on systematic queries in four leading scientific databases. 102 articles were read, clustered, and are succinctly described in the paper. The findings are discussed from the perspective of both national cyber strategies and science, and some directions for future research are examined.

A Tool for Enterprise Architecture Analysis Using the PRM Formalism

Enterprise architecture advocates for model-based decision-making on enterprise-wide information system issues. In order to provide decision-making support, enterprise architecture models should not only be descriptive but also enable analysis. This paper presents a software tool, currently under development, for the evaluation of enterprise architecture models. In particular, the paper focuses on how to encode scientific theories so that they can be used for model-based analysis and reasoning under uncertainty. The tool architecture is described, and a case study shows how the tool supports the process of enterprise architecture analysis.

Enterprise Architecture Meta Models for IT/Business Alignment Situations

Enterprise Architecture models can be used to support IT/business alignment. However, existing approaches do not distinguish between different IT/business alignment situations. Since companies face diverse challenges in achieving a high degree of IT/business alignment, a universal ‘one size fits all’ approach does not seem appropriate. This paper proposes to decompose the IT/business alignment problem into tangible qualities for business, IT systems, and IT governance. An explorative study among 162 professionals is used to distinguish four IT/business alignment situations, i.e. four clusters of IT/business alignment problems. These situations each represent the current state according to certain qualities and also the priorities for future development. In order to increase IT/business alignment, enterprise architecture meta models are proposed for each identified situation. One core meta model (to reflect common priorities) as well as situation specific extensions are presented.

Vehicle to Grid — Monte Carlo simulations for optimal Aggregator strategies

Previous work has shown that it could be profitable on some control markets to use Plug-in Hybrid Electric Vehicles (PHEV) as control power resources. This concept, where battery driven vehicles such as PHEVs provide ancillary service to the grid is commonly referred to as Vehicle to Grid (V2G). The idea is to sell the capacity and energy of the parked PHEVs on the control market. Due to the fact that cars on average are parked 92% of the day, the availability of this capacity could be very high, even though it will be highly dependent on commuting patterns in peak hours. However, as each PHEV has a very small capacity from a grid perspective, it is necessary to implement an aggregating control system, managing a large number of vehicles. This paper presents strategies for an Aggregator to fulfill control bids on the German control markets. These strategies are tested with respect to reliability, efficiency and profitability in a Monte Carlo simulation model. The model is based on available data on the distributions of commuting departure times and travel distances, as well as average driving power consumption, PHEV battery capacities and the market constraints of the secondary control market in Germany.

EAF2- A Framework for Categorizing Enterprise Architecture Frameworks

What constitutes an enterprise architecture framework is a contested subject. The contents of present enterprise architecture frameworks thus differ substantially. This paper aims to alleviate the confusion regarding which framework contains what by proposing a meta framework for enterprise architecture frameworks. By using this meta framework, decision makers are able to express their requirements on what their enterprise architecture framework must contain and also to evaluate whether the existing frameworks meets these requirements. An example classification of common EA frameworks illustrates the approach.

Enterprise architecture availability analysis using fault trees and stakeholder interviews

The availability of enterprise information systems is a key concern for many organisations. This article describes a method for availability analysis based on Fault Tree Analysis and constructs from the ArchiMate enterprise architecture (EA) language. To test the quality of the method, several case-studies within the banking and electrical utility industries were performed. Input data were collected through stakeholder interviews. The results from the case studies were compared with availability of log data to determine the accuracy of the methods predictions. In the five cases where accurate log data were available, the yearly downtime estimates were within eight hours from the actual downtimes. The cost of performing the analysis was low; no case study required more than 20 man-hours of work, making the method ideal for practitioners with an interest in obtaining rapid availability estimates of their enterprise information systems.

P2AMF: Predictive, Probabilistic Architecture Modeling Framework

In the design phase of business and software system development, it is desirable to predict the properties of the system-to-be. Existing prediction systems do, however, not allow the modeler to express uncertainty with respect to the design of the considered system. In this paper, we propose a formalism, the Predictive, Probabilistic Architecture Modeling Framework (P2AMF), capable of advanced and probabilistically sound reasoning about architecture models given in the form of UML class and object diagrams. The proposed formalism is based on the Object Constraint Language (OCL). To OCL, P2AMF adds a probabilistic inference mechanism. The paper introduces P2AMF, describes its use for system property prediction and assessment, and proposes an algorithm for probabilistic inference.

Availability of enterprise IT systems: an expert-based Bayesian framework

Ensuring the availability of enterprise IT systems is a challenging task. The factors that can bring systems down are numerous, and their impact on various system architectures is difficult to predict. At the same time, maintaining high availability is crucial in many applications, ranging from control systems in the electric power grid, over electronic trading systems on the stock market to specialized command and control systems for military and civilian purposes. This paper describes a Bayesian decision support model, designed to help enterprise IT system decision-makers evaluate the consequences of their decisions by analyzing various scenarios. The model is based on expert elicitation from 50 experts on IT systems availability, obtained through an electronic survey. The Bayesian model uses a leaky Noisy-OR method to weigh together the expert opinions on 16 factors affecting systems availability. Using this model, the effect of changes to a system can be estimated beforehand, providing decision support for improvement of enterprise IT systems availability. The Bayesian model thus obtained is then integrated within a standard, reliability block diagram-style, mathematical model for assessing availability on the architecture level. In this model, the IT systems play the role of building blocks. The overall assessment framework thus addresses measures to ensure high availability both on the level of individual systems and on the level of the entire enterprise architecture. Examples are presented to illustrate how the framework can be used by practitioners aiming to ensure high availability.

Optimal IT Service Availability: Shorter Outages, or Fewer?

High enterprise IT service availability is a key success factor throughout many industries. While understanding of the economic importance of availability management is becoming more widespread, the implications for management of Service Level Agreements (SLAs) and thinking about availability risk management are just beginning to unfold. This paper offers a framework within which to think about availability management, highlighting the importance of variance of outage costs. The importance of variance is demonstrated using simulations on existing data sets of revenue data. An important implication is that when outage costs are proportional to outage duration, more but shorter outages should be preferred to fewer but longer, in order to minimize variance. Furthermore, two archetypal cases where the cost of an outage depends non-linearly on its duration are considered. An optimal outage length is derived, and some guidance is also given for its application when the variance of hourly downtime costs is considered. The paper is concluded with a discussion about the feasibility of the method, its practitioner relevance and its implications for SLA management.

A Tool for Interoperability Analysis of Enterprise Architecture Models using Pi-OCL

Decision-making on enterprise-wide information system issues can be furthered by the use of models as advocated by the discipline of enterprise architecture. In order to provide decision-making support, enterprise architecture models should be amenable to analyses. This paper presents a software tool, currently under development, for interoperability analysis of enterprise architecture models. In particular, the ability to query models for structural information is the main focus of the paper. Both the tool architecture and its usage is described and exemplified.