Precursor Analysis for Offshore Oil and Gas Drilling: From Prescriptive to Risk-Informed Regulation

The Oil Spill Commission’s chartered mission—to “develop options to guard against … any oil spills associated with offshore drilling in the future” (National Commission 2010)—presents a major challenge: how to reduce the risk of low-frequency oil spill events, and especially high-consequence events like the Deepwater Horizon accident, when historical experience contains few oil spills of material scale and none approaching the significance of the Deepwater Horizon. In this paper, we consider precursor analysis as an answer to this challenge, addressing first its development and use in nuclear reactor regulation and then its applicability to offshore oil and gas drilling. We find that the nature of offshore drilling risks, the operating information obtainable by the regulator, and the learning curve provided by 30 years of nuclear experience make precursor analysis a promising option available to the U.S. Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE) to bring cost-effective, risk-informed oversight to bear on the threat of catastrophic oil spills.catastrophic oil spills, quantitative risk analysis, risk-informed regulation

Soluble Fermentable Dietary Fibre (Pectin) Decreases Caloric Intake, Adiposity and Lipidaemia in High-Fat Diet-Induced Obese Rats

Funding: This work was funded by the Scottish Government Rural and Environment Science and Analytical Services Division. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Assessing Changeability in Aerospace Systems Architecting and Design Using Dynamic Multi-Attribute Tradespace Exploration

A framework for assessing changeability in the context of dynamic Multi-Attribute Tradespace Exploration (MATE) is proposed and applied to three aerospace systems. The framework consists of two parts. First, changeability concepts such as flexibility, scalability, and robustness are defined in a value-centric context. These system properties are shown to relate “real-space to value-space” dynamic mappings to stakeholder-defined subjective “acceptable cost” thresholds. Second, network analysis is applied to a series of temporally linked tradespaces, allowing for the quantification of changeability as a decision metric for comparison across system architecture and design options. The quantifiable is defined as the filtered outdegree of each design node in a tradespace network formed by linking design options through explicitly defined prospective transition paths. Each of the system application studies are assessed in the two part framework and within each study, observations are made regarding the changeability of various design options. The three system applications include a hypothetical low Earth orbit satellite mission, a currently deployed weapon system, and a proposed large astronomical on-orbit observatory. Preliminary cross-application observations are made regarding the embedding of changeability into the system architecture or design. Results suggest that the low Earth orbit satellite mission can increase its changeability by having the ability to readily change its orbit. The weapon system can increase its changeability by continuing to embrace modularity, use of commercial off-the-shelf parts (COTS), and simple, excess capacity interfaces. The large astronomical observatory can increase its potential changeability by having the ability to reconfigure its physical payloads and reschedule its observing tasks. The analysis approach introduced in this paper is shown to be a powerful concept for focusing discussion, design, and assessment of the changeability of aerospace systems

Guiding Cooperative Stakeholders to Compromise Solutions Using an Interactive Tradespace Exploration Process

Engineering projects frequently involve the cooperation of multiple stakeholders with varying objectives and preferences for the resulting system. Finding a mutually agreeable solution is of paramount importance in order to assure the successful completion of these projects, particularly when different stakeholders are splitting the costs because none can afford to finance the project on their own. This paper proposes a process for uncovering potential mutually agreeable solutions between conflicting stakeholders, without relying on hypothetical aggregate or super-stakeholder preferences, by using guided individual preference compromises and efficiency tradeoffs. Opportunities for experimentally testing the process, with results investigating its usability and solution quality, are discussed. Further directions to improve and expand the process are also discussed, with attention paid to the design of the process as it relates to promoting an implied concept of “goodness” or “fairness” of compromise along with the ability of the process to incorporate advanced interactive technology to improve knowledge retention and understanding of the participating stakeholders.Massachusetts Institute of Technology. Systems Engineering Advancement Research Initiativ

Considerations for an Extended Framework for Interactive Epoch-Era Analysis

AbstractEpoch-Era Analysis (EEA) is a framework that supports narrative and computational scenario planning and analysis for both short run and long run futures. Currently EEA is being applied to frame problems faced by the DoD's Engineered Resilient Systems (ERS) efforts. Because of the large amount of data that must be analyzed when extending EEA to large-scale problems, such as those posed by DoD, a “big data” problem is introduced. This motivates the need for extensions to EEA methods that overcome the computational and human cognition issues that arise as a result. The research presented here describes exploratory development of Interactive Epoch-Era Analysis (IEEA) methods, including human interface and reasoning considerations for epoch and era characterizations, as well as single and multi- epoch and era analyses. Visualization techniques and methods for mitigating computational resource restrictions that facilitate improved decision-making are also presented

Dose-dependent effects of a soluble dietary fibre (pectin) on food intake, adiposity, gut hypertrophy and gut satiety hormone secretion in rats

Acknowledgments We thank Donna Wallace and Animal House staff at the Rowett Institute of Nutrition and Health for the daily care of experimental rats and for the body weight, food intake and MRI measurements.Peer reviewedPublisher PD

Defining System Changeability: Reconciling Flexibility, Adaptability, Scalability, and Robustness for Maintaining System Lifecycle Value

Designing and maintaining systems in a dynamic contemporary environment requires a rethinking of how systems provide value to stakeholders over time. Classically, two different approaches to promoting value sustainment may include developing either alterable or robust systems. The first accomplishes value delivery through altering the system to meet new needs, while the second accomplishes value delivery through maintaining a system to meet needs in spite of changes. The definitions of flexibility, adaptability, scalability, and robustness are shown to be different parts of the core concept of “changeability,” which can be described by three aspects: change agents, change effects, and change mechanisms. Cast in terms of system parameter changes, flexibility and adaptability are shown to relate to the origin of the change agent (external or internal to a system boundary respectively). Scalability and robustness, along with the additional property of modifiability, are shown to relate to change effects. The extent of changeability is determined by the number of possible change mechanisms available to the system as accepted by decision makers. Creating changeable systems, which can incorporate both classical notions of alterability and robustness, empowers systems to maintain value delivery over their lifecycle, in spite of changes in their contexts, thereby achieving value robustness to stakeholders over time

Multi-Attribute Tradespace Exploration as Front End for Effective Space System Design

The inability to approach systematically the high level of ambiguity present in the early design phases of space systems causes long, highly iterative, and costly design cycles. A process is introduced and described to capture decision maker preferences and use them to generate and evaluate a multitude of space system designs, while providing a common metric that can be easily communicated throughout the design enterprise. Communication channeled through formal utility interviews and analysis enables engineers to better understand the key drivers for the system and allows for a more thorough exploration of the design tradespace. Multi-attribute tradespace exploration with concurrent design, a process incorporating decision theory into model- and simulation-based design, has been applied to several space system projects at the Massachusetts Institute of Technology. Preliminary results indicate that this process can improve the quality of communication to resolve more quickly project ambiguity and to enable the engineer to discover better value designs for multiple stakeholders. The process is also integrated into a concurrent design environment to facilitate the transfer of knowledge of important drivers into higher fidelity design phases. Formal utility theory provides a mechanism to bridge the language barrier between experts of different backgrounds and differing needs, for example, scientists, engineers, managers, etc. Multi-attribute tradespace exploration with concurrent design couples decision makers more closely to the design and, most important, maintains their presence between formal reviews