Business Process Event Log Transformation into Bayesian Belief Network

Business process (BP) mining has been recognized in business intelligence and reverse engineering fields because of the capabilities it has to discover knowledge about the implementation and execution of BP for analysis and improvement. Existing business knowledge extraction solutions in process mining context requires repeating analysis of event logs for each business knowledge extraction task. The probabilistic modelling could allow improved performance of BP analysis. Bayesian belief networks are a probabilistic modelling tool and the paper presents their application in BP mining. The paper shows that existing process mining algorithms are not suited for this, since they allow for loops in the extracted BP model that do not really exist in the event log,and presents a custom solution for directed acyclic graph extraction. The paper presents results of a synthetic log transformation into Bayesian belief network showing possible application in business intelligence extraction and improved decision support capabilities

Using Bayesian belief networks for reliability management : construction and evaluation: a step by step approach

In the capital goods industry, there is a growing need to manage reliability throughout the product development process. A number of trends can be identified that have a strong effect on the way in which reliability prediction and management is approached, i.e.: - The lifecycle costs approach that is becoming increasingly important for original equipment manufacturers - The increasing product complexity - The growth in customer demands - The pressure of shortening times to market - The increasing globalization of markets and production Reliability management is typically based on the insights, views, and perceptions of the real world of the people that are involved in the process of decision making. These views are unique and specific for each involved individual that looks at the management process and can be represented using soft systems methodology. Since soft systems methodology is based on insights, view and perceptions, it is especially suitable in the context of reliability prediction and management early in the product development process as studied in this thesis (where there is no objective data available (yet)). Two research objectives are identified through examining market trends and applying soft systems methodology. The first research objective focuses on the identification or development of a method for reliability prediction and management that meets the following criteria: - It should support decision making for reliability management - It should be able to also take non-technical factors into account - It has to be usable throughout the product development process and especially in the early phases of the process. - It should be able to capture and handle uncertainty This first research objective is addressed through a literature study of traditional approaches (failure mode and effects analysis, fault tree analysis and database methods), and more recent approaches to reliability prediction and reliability management (REMM, PREDICT and TRACS). The conclusion of the literature study is that traditional methods, although able to support decision making to some extent, take a technical point of view, and are usable only in a limited part of the product development process. The traditional methods are capable of taking uncertainty into account, but only uncertainty about the occurrence of single faults or failure modes. The recent approaches are able to meet the criteria to a greater extent: REMM is able to provide decision support, but mainly on a technical level, by prioritizing the elimination of design concerns. The reliability estimate provided by REMM can be updated over time and is clearly usable throughout the product development process. Uncertainty is incorporated in the reliability estimate as well as in the occurrence of concerns. PREDICT provides decision support for processes as well as components, but it focuses on the technical contribution of the component or process to reliability. As in REMM, PREDICT provides an updateable estimate, and incorporates uncertainty as a probability. TRACS uses Bayesian belief networks and provides decision support both in technical and non-technical terms. In the TRACS tool, estimates can be updated and uncertainty is incorporated using probabilities. Since TRACS is developed for one specific case, and an extensive discussion on the implementation process is missing, it is not readily applicable for reliability management in general. The discussion of literature leads to the choice of Bayesian belief networks as an effective modelling technique for reliability prediction and management. It also indicates that Bayesian belief networks are particularly well suited in the early stages of the product development process, because of their ability to make the influences of the product development process on reliability already explicit from the early stages of the product development process onwards. The second research objective is the development of a clear, systematic approach to build and use Bayesian belief networks in the context of reliability prediction and management. Although Bayesian belief network construction is widely described in the literature as having three generic steps (problem structuring, instantiation and inference), how the steps are to be made in practice is described only summarily. No systematic, coherent and structured approach for the construction of a Bayesian belief network can be found in literature. The second objective therefore concerns the identification and definition of model boundaries, model variables, and model structure. The methodology developed to meet this second objective is an adaptation of Grounded Theory, a method widely used in the social sciences. Grounded Theory is an inductive rather than deductive method (focusing on building rather than testing theory). Grounded Theory is adapted by adopting Bayesian network idioms (Neil, Fenton & Nielson, 2000) into the approach. Furthermore, the canons of the Grounded Theory methodology (Corbin & Strauss, 1990) were not strictly followed because of their limited suitability for the subject, and for practical reasons. Grounded Theory has been adapted as a methodology for structuring problems modelled with Bayesian belief networks. The adapted Grounded Theory approach is applied in a case study in a business unit of a company that develops and produces medical scanning equipment. Once the Bayesian belief net model variables, structure and boundaries have been determined the network must be instantiated. For instantiation, a probability elicitation protocol has been developed. This protocol includes a training, preparation for the elicitation, a direct elicitation process, and feedback on the elicitation. The instantiation is illustrated as part of the case study. The combination of the adapted Grounded Theory method for problem structuring, and the probability elicitation protocol for instantiation together form an algorithm for Bayesian belief network construction (consisting of data gathering, problem structuring, instantiation, and feedback) that consists of the following 9 steps (see Table 1). Table 1: Bayesian belief network construction algorithm 1. Gather information regarding the way in which the topic under discussion is influenced by conducting interviews 2. Identify the factors (i.e. nodes) that influence the topic, by analyzing and coding the interviews 3. Define the variables by identifying the different possible states (state-space) of the variables through coding and direct conversation with experts 4. Characterize the relationships between the different nodes using the idioms through analysis and coding of the interviews 5. Control the number of conditional probabilities that has to be elicited using the definitional/synthesis idiom (Neil, Fenton & Nielson, 2000) 6. Evaluate the Bayesian belief network, possibly leading to a repetition of (a number of) the first 5 steps 7. Identify and define the conditional probability tables that define the relationships in the Bayesian belief network 8. Fill in the conditional probability tables, in order to define the relationships in the Bayesian belief network 9. Evaluate the Bayesian belief network, possibly leading to a repetition of (a number of) earlier steps A Bayesian belief network for reliability prediction and management was constructed using the algorithm. The model’s problem structure and the model behaviour are validated during and at the end of the construction process. A survey was used to validate the problem structure and the model behaviour was validated through a focus group meeting. Unfortunately, the results of the survey were limited, because of the low response rate (35%). The results of the focus group meeting indicated that the model behaviour was realistic, implying that application of the adapted Grounded Theory approach results in a realistic model for reliability management. The adapted Grounded Theory approach developed in this thesis provides a scientific and practical contribution to model building and use in the face of limited availability of information. The scientific contribution lies in the provision of the systematic and coherent approach to Bayesian belief network construction described above. The practical contribution lies in the application of this approach in the context of reliability prediction and management and in the structured and algorithmic approach to model building. The case study in this thesis shows the construction and use of an effective model that enables reliability prediction, and provides decision support for reliability management throughout the product development process from the earliest stages of the process. Bayesian belief networks provide a strong basis for reliability management, giving qualitative and quantitative insights in relationships between influential variables and reliabilit

Integration of biological, economic and sociological knowledge by Bayesian belief networks: the interdisciplinary evaluation of potential Baltic salmon management plan

There is a growing need to evaluate fisheries management plans in a comprehensive interdisciplinary context involving stakeholders. In this paper we demonstrate a probabilistic management model to evaluate potential management plans for Baltic salmon fisheries. The analysis is based on several studies carried out by scientists from respective disciplines. The main part consisted of biological and ecological stock assessment with integrated economic analysis of the commercial fisheries. Recreational fisheries were evaluated separately. Finally, a sociological study was conducted aimed at understanding stakeholder perspectives and potential commitment to alternative management plans. In order to synthesize the findings from these disparate studies a Bayesian Belief Network (BBN) methodology is used. The ranking of management options can depend on the stakeholder perspective. The trade-offs can be analysed quantitatively with the BBN model by combining, according to the decision maker’s set of priorities, utility functions that represent stakeholders’ views. We show how BBN can be used to evaluate robustness of management decisions to different priorities and various sources of uncertainty. In particular, the importance of sociological studies in quantifying uncertainty about the commitment of fishermen to management plans is highlighted by modelling the link between commitment and implementation success.Baltic salmon, bio-economic modelling, Bayesian Belief Network, expert knowledge, fisheries management, commitment and implementation uncertainty, management plan, recreational fisheries, stakeholders., Resource /Energy Economics and Policy,

Potentials and Limits of Bayesian Networks to Deal with Uncertainty in the Assessment of Climate Change Adaptation Policies

Bayesian networks (BNs) have been increasingly applied to support management and decision-making processes under conditions of environmental variability and uncertainty, providing logical and holistic reasoning in complex systems since they succinctly and effectively translate causal assertions between variables into patterns of probabilistic dependence. Through a theoretical assessment of the features and the statistical rationale of BNs, and a review of specific applications to ecological modelling, natural resource management, and climate change policy issues, the present paper analyses the effectiveness of the BN model as a synthesis framework, which would allow the user to manage the uncertainty characterising the definition and implementation of climate change adaptation policies. The review will let emerge the potentials of the model to characterise, incorporate and communicate the uncertainty, with the aim to provide an efficient support to an informed and transparent decision making process. The possible drawbacks arising from the implementation of BNs are also analysed, providing potential solutions to overcome them.Adaptation to Climate Change, Bayesian Network, Uncertainty