This paper presents a decision support system (DSS) for the modeling and management of project risks and risk interactions. This is a crucial activity in project management, as projects are facing a growing complexity with higher uncertainties and tighter constraints. Existing classical methods have limitations for modeling the complexity of project risks. For example, some phenomena like chain reactions and loops are not properly taken into account. This will influence the effectiveness of decisions for risk response planning and will lead to unexpected and undesired behavior in the project. Based on the concepts of DSS and the classical steps of project risk management, we develop an integrated DSS framework including the identification, assessment and analysis of the risk network. In the network, the nodes are the risks and the edges represent the cause and effect potential interactions between risks. The proposed simulation-based model makes it possible to re-evaluate risks and their priorities, to suggest and test mitigation actions, and then to support project manager in making decisions regarding risk response actions. An example of application is provided to illustrate the utility of the model.

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A simulation-based risk network model for decision support in project risk management

Many risks are involved in software development and risk management has become one of the key activities in software development. Bayesian networks (BNs) have been explored as a tool for various risk management practices, including the risk management of software development projects. However, much of the present research on software risk analysis focuses on finding the correlation between risk factors and project outcome. Software project failures are often a result of insufficient and ineffective risk management. To obtain proper and effective risk control, risk planning should be performed based on risk causality which can provide more risk information for decision making. In this study, we propose a model using BNs with causality constraints (BNCC) for risk analysis of software development projects. Through unrestricted automatic causality learning from 302 collected software project data, we demonstrated that the proposed model can not only discover causalities in accordance with the expert knowledge but also perform better in prediction than other algorithms, such as logistic regression, C4.5, Naive Bayes, and general BNs. This research presents the first causal discovery framework for risk causality analysis of software projects and develops a model using BNCC for application in software project risk management.

Software project risk analysis using Bayesian networks with causality constraints

A novel risk analysis approach is developed by merging interval-valued fuzzy sets (IVFSs), improved Dempster–Shafer (D–S) evidence theory, and fuzzy Bayesian networks (BNs), acting as a systematic decision support approach for safety insurance for the entire life cycle of a complex system under uncertainty. Aiming to alleviate the problem of insufficient and imprecise data collected from the complicated environment, the expert judgment in linguistic expressions is employed to describe the risk levels for all risk factors, which are represented by IVFSs using Gaussian membership function to fully consider such fuzziness and uncertainty. In regard to interval fusion and highly conflicting data, an improved combination rule based on the D–S evidence theory is developed. Then, fuzzy prior probability for each risk factor can be generated from fused intervals and fed into a fuzzy BN model for fuzzy-based Bayesian inference, including predictive, sensitivity, and diagnosis analysis. Furthermore, a case study is used to demonstrate the feasibility of the proposed risk analysis. A comparison of risk analysis based upon the hybrid improved D–S, classical D–S, and arithmetic average method is illustrated to show the outstanding performance of the developed approach in fusing multisource information with ubiquitous uncertainty and conflicts in an efficient manner, leading to more reliable risk evaluation. It is concluded that the proposed risk analysis provides a deep insight on risk control, especially for complex project environment, which enables to not only reduce the likelihood of failure ahead of time but also mitigate risk magnitudes to some degree after the occurrence of a failure.

Improved Fuzzy Bayesian Network-Based Risk Analysis With Interval-Valued Fuzzy Sets and D–S Evidence Theory

Risk Management in Construction Projects: A Knowledge-based Approach

ion Abstraction means to focus on the essential features of an element or object in OOP, ignoring its extraneous or accidental properties. The essential features are relative to the context in which the object is being used. Grady Booch has defined abstraction as follows: “An abstraction denotes the essential characteristics of an object that distinguish it from all other kinds of objects and thus provide crisply defined conceptual boundaries, relative to the perspective of the viewer.” Example : When a class Student is designed, the attributes enrolment_number, name, course, and address are included while characteristics like pulse_rate and size_of_shoe are eliminated, since they are irrelevant in the perspective of the educational institution.

Object-Oriented Analysis & Design.

This paper presents a scheme for large engineering project risk management using a Bayesian belief network and applies it to the Korean shipbuilding industry. Twenty-six different risks were deduced from expert interviews and a literature review. A survey analysis was conducted on 252 experts from 11 major Korean shipbuilding companies in April 2007. The overall major risks were design change, design manpower, and raw material supply as internal risks, and exchange rate as external risk in both large-scale and medium-sized shipbuilding companies. Differences of project performance risks between large-scale and medium-sized shipbuilding companies were identified. Exceeding time schedule and specification discontent were more important to large-scale shipbuilding companies, while exceeding budget and exceeding time schedule were more important to medium-sized shipbuilding companies. The change of project performance risks was measured by risk reduction activities of quality management, and strikes at headquarters and subcontractors, in both large-scale and medium-sized shipbuilding companies. The research results should be valuable in enabling industrial participants to manage their large engineering project risks and in extending our understanding of Korean shipbuilding risks.

Large engineering project risk management using a Bayesian belief network

A fully automated line heating (LH) process includes a control system (software) and an automated machine (hardware). The software and hardware need to be developed concurrently in order to verify and maximize the efficiency of the new process. However, most shipyards have developed these separately for an automated LH process. The development also involves extensive calculations of computer-aided design, manufacturing, and engineering (CAD/CAM/CAE) information. Thus, it cannot be user friendly for technicians. The objective of this paper is to describe the entire engineering concept for the automation of LH process. Based on the object-oriented methodology, a control system and an automated machine were developed simultaneously. The main function of the control system is to provide real-time heating information to technicians or automated machines. The information includes heating location, torch speed, heating sequence, and other related information. These data are derived from CAD/CAM/CAE applications. With the calculated heating information, the machine provides automated LH tasks and collects relevant information during and after the task. The developed system shows a user-friendly capability for shipyard operators and includes advanced engineering calculations for accurate plate fabrication. A specific example was performed, in order to verify the system. Details of the applications will be described in the paper.

User-Friendly, Advanced Line Heating Automation for Accurate Plate Forming

In this paper we propose a geometric assessment method in order to establish a theoretical foundation for the automation of fabricating curved steel plates through the line-heating process in shipbuilding. We focus on measurement, comparison and the measurement data process in the overall system which was developed at Seoul National University, Korea, Shin et al. [Shin JG, Ryu CH, Lee JH, Kim WD. A user-friendly, advanced line-heating automation for accurate plate fabrication. Journal of Ship Production 2003;19(1):8–15]. The measurement is performed using a scanning device, which provides the digitized geometric data of a curved plate. The measured data are then positioned against a design plate so that comparison between them is made to determine whether we have obtained the desired shape. If not, the data are approximated in B -spline surface form and the approximated surface and the measured data are processed to extract necessary information for computing heating lines for the next iteration. Experiments are performed with a real ship hull plate and the result shows the potential of the proposed procedure for the automation of the line-heating manufacturing process at the shipyard.

Geometric assessment for fabrication of large hull pieces in shipbuilding

The management of a panel block shop in a shipyard is a complex process that entails the largest amount of work and in which many decisions are involved. Shipbuilders have considered the process as a bottleneck since every panel for every ship must be processed through the shop. The objective of this research is to carry out a materials flow analysis to maximise process productivity and to place simulation optimisation technology in the hands of decision makers, such as production planners and supervisors. In this article, a production execution planning system is proposed for panel block operations utilising discrete-event simulation and simulated annealing. The simulation model was validated using a real production scenario and the comparison showed a very favourable agreement between the actual panel shop and the simulation model. The proposed system supports production planners by general dispatching rules and optimisation to make better scheduling decisions on the shop floor. The system will provide ...

Development of simulation-based production execution system in a shipyard: a case study for a panel block assembly shop

This invention relates to an automatic machine to form curved plates (100) of ship's hull-pieces in shipbuilding process. This automatic machine has the following devices in order to improve such state such as Jig table (10) to support steel plates, heating device (21) including a torch to heat one side of steel plates up to the required temperature (about 800 °C), setting up over a jig table and moving before and behind, and left and right, cooling device (31) to cool down the heated plates by spraying out coolant from several nozzles (32), which is set up around a torch and moves along the same path as the torch, measuring device (41) to measure the formed plates and other information with a gauge (41) to be set up beside the cooling device, and to transmit the data to the control system through A/D converter (42) to convert analogue signals sent by the gauge to digital signals, driving device to include a transverse guide rail (51), a longitudinal guide rail (52), motors, chains, belts, etc., all of which enable the torch, the cooler, and the measuring gauge to move in accordance with commands of a control system.

Jong Gye Shin

Papers

Large engineering project risk management using a Bayesian belief network

User-Friendly, Advanced Line Heating Automation for Accurate Plate Forming

Geometric assessment for fabrication of large hull pieces in shipbuilding

Development of simulation-based production execution system in a shipyard: a case study for a panel block assembly shop

Automatic machine for the formation of ship's curved hull-pieces