Use Of Multiple Scenarios Research Articles

KarstNSim: A graph-based method for 3D geologically-driven simulation of karst networks

In karst aquifers, groundwater flow is highly influenced by the interconnected underground cavities and conduits that form the karst network. Modeling karst flows requires the use of spatially distributed approaches accounting for these networks. Their exploration is, however, often complex, and mapping them using indirect methods such as geophysical ones has proven challenging. To overcome these limitations, stochastically simulating discrete karst networks should account for the uncertainties on conduit position and geometry. Only a few existing methods can reproduce realistic and diverse karst morphologies. In this work, we propose a new algorithm, KarstNSim, for simulating discrete karst networks, that incorporates field data to generate a range of possible karst network geometries. It relies on the computation of the shortest path between the inlets and outlets of the network with the use of an anisotropic cost function defined on an n-nearest neighbor graph conformal to geological and structural heterogeneities. This cost function represents the physico-chemical processes that govern speleogenesis – such as erosion and chemical weathering – providing simplified control over the geometry of the generated networks. Our approach reproduces the vadose-phreatic partition visible in the karst networks, by generating sub-vertical conduits in the unsaturated zone and sub-horizontal ones in the saturated part. It encompasses geological parameters such as inception surfaces, fractures, permeability, and solubility of layers, along with considering the hydrological context of recharge by assigning relative weights to the inlets. We simulate various synthetic models to demonstrate the influence of different input parameters on the spatial organization of the past and present karst flows. We also apply KarstNSim to a real case study – the Ribeaucourt system (Meuse, France) – and use available data to generate realistic karst networks. The lack of knowledge on the Ribeaucourt network geometry is alleviated by the use of multiple scenarios corresponding to different sets of weights in the cost function, resulting in a variety of network morphologies which represent the uncertainty on the real geometry. The geometrical and topological metrics computed on the simulated networks generally overlap with those of real ones, suggesting the reliability of the method.

The Influence of Police Reporting Styles on the Processing of Crime Related Information

Police records drawn up during or after a suspect's police interrogation play a crucial role in judicial systems and should therefore be factual representations of what occurred in the spoken interrogation. Within the judicial domain, however, little is known about how style of reporting (i.e., the specific language used) affects the interpretation of these facts. Furthermore, the relationship between police record ‘quality’ and variations in judgment of guilt, credibility or reliability has not been studied to date. In three studies, we investigated the influence of three commonly used recording styles (i.e., monolog, recontextualized and question-answer style) on judgments of guilt, credibility, and reliability in fictitious criminal cases. We hypothesized that participants would (1) find records in the question-answer style more credible and reliable than those in the monolog or recontextualized style, and (2) consider the recontextualized style to be the least credible and reliable. Experiment 1 showed that the Q&A style was perceived as more reliable than the other two styles. Experiment 2, a replication in which we also tested new hypotheses based on explorative analyses of Experiment 1, showed no effects of reporting style. To investigate whether the discrepancy in results was due to different scenarios, a third experiment that made use of multiple scenarios was conducted. We found effects of reporting style on perceived accuracy, imageability, and understandability. In sum, this study showed that factors as subtle as reporting style might impact the processing of information in contexts where only factual information should be taken into account.

Landscape structure and management alter the outcome of a pesticide ERA: Evaluating impacts of endocrine disruption using the ALMaSS European Brown Hare model

There is a gradual change towards explicitly considering landscapes in regulatory risk assessment. To realise the objective of developing representative scenarios for risk assessment it is necessary to know how detailed a landscape representation is needed to generate a realistic risk assessment, and indeed how to generate such landscapes. This paper evaluates the contribution of landscape and farming components to a model based risk assessment of a fictitious endocrine disruptor on hares. In addition, we present methods and code examples for generation of landscape structures and farming simulation from data collected primarily for EU agricultural subsidy support and GIS map data.Ten different Danish landscapes were generated and the ERA carried out for each landscape using two different assumed toxicities. The results showed negative impacts in all cases, but the extent and form in terms of impacts on abundance or occupancy differed greatly between landscapes. A meta-model was created, predicting impact from landscape and farming characteristics. Scenarios based on all combinations of farming and landscape for five landscapes representing extreme and middle impacts were created. The meta-models developed from the 10 real landscapes failed to predict impacts for these 25 scenarios. Landscape, farming, and the emergent density of hares all influenced the results of the risk assessment considerably.The study indicates that prediction of a reasonable worst case scenario is difficult from structural, farming or population metrics; rather the emergent properties generated from interactions between landscape, management and ecology are needed. Meta-modelling may also fail to predict impacts, even when restricting inputs to combinations of those used to create the model. Future ERA may therefore need to make use of multiple scenarios representing a wide range of conditions to avoid locally unacceptable risks. This approach could now be feasible Europe wide given the landscape generation methods presented.

Radical uncertainty: scenario planning for futures

The use of scenario planning in urban and regional planning practice has grown in the last decade as one way to face uncertainty. However, in adapting scenario planning from its origins in the business sector, planners have eliminated two key components: (1) the use of multiple scenarios, and (2) the inclusion of diverse organizations, people, and interests through deep deliberations. We argue that this shift limits the ability of planners to plan for multiple plausible futures that are shaped by an increasing number of diverse actors. In this paper, we use case-study research to examine how uncertainty was considered in four scenario-planning processes. We analyzed and compared the cases based on analytical categories related to multiple futures and diversity. We found that the processes that used multiple, structurally distinct scenarios explored a wider range of topics and issues shaping places. All four relied heavily on professional stakeholders as the scenario developers, limiting public input. Only one of the processes that included multiple futures captured the differential effects that scenarios would have on diverse people and interests. Overall, the purpose of the scenario planning drove the participant diversity and ultimately the quality and use of the scenarios.

Effect of scenario planning on field experts' judgment of long-range investment decisions

We present the results of three field experiments demonstrating the effect of scenario planning on field experts' judgment of several long-range investment decisions. Our results show, contrary to past findings, that the use of multiple scenarios does not cause an aggregate increase or decrease in experts' confidence in their judgment. Rather, expert judgment changes in accordance with how an investment fares in a given scenario: it becomes more favorable if the investment is found to be useful for a particular scenario used by the expert, and vice versa. This scenario-induced change is moderated by the expert's confidence in his/her judgment before using the scenario. Finally, our results show that field experts prefer more flexible options to make specific long-range investments after using multiple scenarios. Copyright © 2014 John Wiley & Sons, Ltd.

Standardized assessment for evaluation of team skills: validity and feasibility.

The authors developed a Standardized Assessment for Evaluation of Team Skills (SAFE-TeamS) in which actors portray health care team members in simulated challenging teamwork scenarios. Participants are scored on scenario-specific ideal behaviors associated with assistance, conflict resolution, communication, assertion, and situation assessment. This research sought to provide evidence of the validity and feasibility of SAFE-TeamS as a tool to support the advancement of science related to team skills training. Thirty-eight medical and nursing students were assessed using SAFE-TeamS before and after team skills training. The SAFE-TeamS pretraining and posttraining scores were compared, and participants were surveyed. Generalizability analysis was used to estimate the variance in scores associated with the following: examinee, scenario, rater, pretraining/posttraining, examinee type, rater type (actor-live vs. external rater-videotape), actor team, and scenario order. The SAFE-TeamS scores reflected improvement after training and were sensitive to individual differences. Score variance due to rater was low. Variance due to scenario was moderate. Estimates of relative reliability for 2 raters and 8 scenarios ranged from 0.6 to 0.7. With fixed scenarios and raters, 2 raters and 2 scenarios, reliability is greater than 0.8. Raters believed SAFE-TeamS assessed relevant team skills. Examinees' responses were mixed. The SAFE-TeamS was sensitive to individual differences and team skill training, providing evidence for validity. It is not clear whether different scenarios measure different skills and whether the scenarios cover the necessary breadth of skills. Use of multiple scenarios will support assessment across a broader range of skills. Future research is required to determine whether assessments using SAFE-TeamS will translate to performance in clinical practice.

Integrating Reserves Management: Providing Regulatory Compliance and Improving Decision Making

This article, written by Senior Technology Editor Dennis Denney, contains highlights of paper SPE 124168, "Methodology for Integrated Reserves Management: Providing Regulatory Compliance and Im proving Decision Making," by Lev Virine, SPE, Project Decisions, and Doug MacDonald, SPE, Schlumberger Information Solutions, prepared for the 2009 SPE Annual Technical Conference and Exhibition, New Orleans, 4-7 October. The paper has not been peer reviewed. Effective corporate reserves-management systems enable tracking reserves to provide input for reporting to regulators and to serve as a decision-support system. Implementation of such reserves-management systems has challenges. Regulatory bodies, including the US Securities and Exchange Commission (SEC), require proper categorization of reserves on the basis of evaluating whether the volumes can be recovered economically in a timely manner. The reserves-management system should provide technical and economic volumes on the basis of up-to-date prices, capture and analyze uncertainties in the reserves volumes, provide secure data access and data archiving, and implement an approval and audit process. Introduction A method to integrate reserves management was developed that comprises three processes—data management, which ensures fast and secure access to reservoir data; economic and technical volume calculation; and a flexible reporting process. Reservoirs, as well as prospects, are organized within a corporate hierarchy. In accordance with SEC regulations and SPE/World Petroleum Council/American Association of Petroleum Geologists/Society of Petroleum Evaluation Engineers Petroleum Resources Management System (SPE-PRMS) guidelines, the data-management process captures proven, probable, and possible reserves, as well as discovered and undiscovered resources, for different petroleum products and companies with different working interests. Each category of each reservoir is associated with an economic case that contains information about costs, prices, and the fiscal regime. Economic volumes can be calculated on the basis of the results of economic evaluations of the reserves. Uncertainties in reservoir data are captured by use of multiple scenarios for each reservoir and category. A regional-pricing mechanism allows updating prices for all economic cases at a particular level of the corporate hierarchy. All changes to the economic-results data would be recorded and require approval. Challenges. Disclosure of oil and gas reserves is different from disclosure of company financial performance or production. While the financial performance of the company, at least in theory, can be calculated precisely, oil and gas reserves are uncertain by definition. Different proven methods of estimating reserves may yield different results. Moreover, different estimators that use similar methods may determine different numbers. New SEC regulations aim to improve transparency by providing investors with more information about the reserves. In particular, the new regulations permit disclosure of probable and possible reserves. It should be noted that information about probable and possible reserves also includes more uncertainties, compared with proven reserves.

Incorporation dynamic aspects and uncertainty in 1-median location problems

In this paper we present several 1-median formulations on a tree network which incorporate dynamic evolution and/or uncertainty of node demands and transportation costs over a planning horizon. Dynamic evolution is modeled using linear demand functions for the nodes and linear length functions for the edges. Uncertainty is modeled with the use of multiple scenarios, where a scenario is a complete specification of the uncertain node demands and/or edge lengths. We formulate our objective using minimax regret like criteria. We use two different criteria, namely, robust deviation and relative robustness. We discuss what motivated the introduction of these objectives, as well as their relation to existing literature and decision making practices. For all of the models presented, we provide low-order polynomial time algorithms.

Comparison of Optimization Formulations for Waste‐Load Allocations

A novel approach for including uncertainty in the water‐quality‐management process is presented. The approach is based on the use of multiple scenarios that reflect possible combinations of hydrologic, meteorologic, and pollutant loading design conditions. Each scenario, which represents possible “future management design conditions,” defines a set of transfer coefficients that describes the pollutant transport process under these design conditions. A general waste‐load‐allocation model is developed for which all sets of transfer coefficients are simultaneously incorporated in the water‐quality constraint set. Several optimization formulations of this general model are examined to evaluate efficient management solutions that account for a range of possible future conditions. The approach is applied to the management of BOD from 10 dischargers on the Willamette River in Oregon. The results indicate that model formulations based on minimizing a measure of total deviations from a target DO level identify efficient solutions for the waste‐load allocation.

A multi-attribute evaluation framework for electric resource acquisition in California

In the competitive environment in which US utilities operate, auctions are becoming an accepted means for procuring resources to meet utilities' projected needs. The rationale for instituting auctions is to effectively harness the competitive forces in electricity resource markets in order to implement least-cost planning objectices. PG&E, in cooperation with the other California investor-owned utilities. Southern California Edison and San Diego Gas and Electric, has developed a multi-attribute auction framework for the procurement of future resources. The framework uses the attributes of capacity and energy price, dispatchability, location, start date flexibility, price diversity, project viability and environmental impacts to evaluate customer benefits. This allows comparability between and tradeoffs among attributes. Other key features include the use of multiple scenarios to explicitly account for fuel price and load growth uncertainty, the explicit evaluation of long-term impacts and dynamic operating benefits of dispatchability, and the use of portfolio theory for the evaluation of price diversity. The bidding evaluation also uses optimal power flow derived loss adjustment factors and incremental network reinforcement costs and takes into account uncertainty in determining start-date flexibility. The framework is sufficiently general to be usable not only for auctions, but also for utility evaluation of maintenance, power contracts and other investment decisions. This paper describes the framework and its implementation into a PC spreadsheet software package.

The use of multiple scenarios in sales forecasting: An empirical test

Nearly 500 annual sales forecasts were generated from the responses of 82 subjects who were presented with either a time-series plot of historical sales data by itself or with the same plus three scenarios, and were then asked to make forecasts. Sales forecasts were made in either a stable or an unstable environment. The findings did not support the claims made by scenario advocates. Scenarios did not make unexpected outcomes less surprising. Instead, scenarios were found to increase confidence in a favored forecast. Furthermore, no support was found for the contention that scenarios improved upon ‘eyeball’ extrapolations or made judgmental sales forecasts more accurate than quantitative extrapolations. Scenarios were found to be tainted by many of the same biases previously identified by cognitive psychologists.

Energy scenarios—the Sizewell experience

This paper reviews recent work within the Electricity Supply industry in the area of medium- to long-term forecasting and planning. It highlights some of the problems in using conventional statistical forecasting methods for this purpose and outlines the construction and use of multiple scenarios for longer term planning. This is illustrated in the context of the scenarios included in the Central Electricity Generating Board's evidence to the public inquiry at Sizewell regarding the construction of a pressurized water reactor power station.

The use of multiple scenarios by U.S. industrial companies: A comparison study, 1977–1981

Over the past 5 years the authors have been examining the Fortune 1000 U.S. industrials' changes in corporate planning practices with respect to environmental analysis. Results of earlier studies have been reported in the February 1979 and October 1981 issues of Long Range Planning. This article documents the rapid, domestic increase in the use of multiple scenarios between 1977 and 1981. Given the intention for future use by present users and the length of time multiple scenarios have been used by some firms, this is strong evidence that multiple scenarios are a useful conjectural tool which can help corporate management plan in an unstable environment.

Using Multiple Scenarios for Strategic Environmental Assessment: Implications for Marketing Management

In this article, we present empirical results that document the critical changes in planning attitudes and practices and their implications on strategic market planning. The particular focus of this article is to illustrate the growing use of multiple scenarios as an approach to strategic environmental assessment, and to present key factors that marketing management must consider when adopting the multiple scenario approach.

The use of multiple scenarios by U.S. industrial companies

A growing number of firms have responded to the ‘unpredictable future’ by developing ways to measure their proposed strategies against several plausible alternative futures. Probably the most widely used of these techniques is multiple (or alternative) scenario analysis (MSA). Survey results indicate that approximately 150 of the Fortune ‘1000’ industrials now use MSA in their formal planning processes. Most have begun using MSA within the last 3 or 4 years. Furthermore, a number of other companies are considering its use. Survey results also show that firms do not follow the relatively rigorous procedures as suggested in the literature. Also, MSA seems to be most successful when management is both knowledgable and involved with scenarios from the beginning.