Multiple scenarios

Osmolality is a measure of the number of osmotically active particles per unit of solution, independent of the weight or nature of the particle. Equimolar concentrations of all substances in the undissociated state exert the same osmotic pressure. Although the normal serum osmolality is 280 to 300 mOsm/kg (280 to 300 mmol/kg), multiple scenarios exist where this value becomes markedly abnormal. The calculated serum osmolality helps determine deviations in TBW content. As such, it is often useful to calculate the serum osmolality as follows ... 

When there are multiple scenarios with the same consequence, each scenario is evaluated individually using Equation 11-30. The frequency of the consequence is subsequently determined using... 

The expected profit across multiple scenarios provides a more realistic picture of the future profit situation compared to one single scenario. However, scenarios are consolidated and averaged in one total number with their probability weights. The planner would have no information about potential worst case profits as a profit basis and might like to sacrifice expected profit opportunities for safety in exchange. This is addressed by the two-phase optimization approach. 

For pesticide risk assessments, it may often be necessary to assess impacts of the same pesticide used in different crops, in different seasons, in different geographic regions, and on different species and ecosystems. This will require the use of multiple scenarios and possibly multiple assessment endpoints. 

Multiple scenarios may also be necessary to allow assessment of endpoints at different levels of temporal, spatial, and biological scale (US SAP 1999). This is because both the risks and their acceptability to stakeholders may differ markedly... 

Another important reason for using multiple scenarios is to represent major sources of variability, or what-if scenarios to examine alternative assumptions about major uncertainties. This can be less unwieldy than including them in the model. Also, the distribution of outputs for each separate scenario will be narrower than when they are combined, which may aid interpretation and credibility. A special case of this occurs when it is desired to model the consequences of extreme or rare events or situations, for example, earthquakes. An example relevant to pesticides might be exposure of endangered species on migration. This use of multiple scenarios in ecological risk assessment has been termed scenario analysis, and is described in more detail in Ferenc and Foran (2000). 

Sloan Management Review 36 25-40 Schoemaker PJH (1993) Multiple Scenario Development Its Conceptual and Behavioral Foundation. Strategic Management Journal 14 193-213... 

The first step is to conduct a valuation of the current business plan, using multiple scenarios if possible. A continuous, internal company valuation is relatively easy to implement, and creates crucial transparency of the value creation potential of the current business plan and its drivers. 

Mangels G] Waterborne Environmental, Inc. 2001. The development of MUSCRAT (multiple scenario risk assessment tool) a software tool for conducting surface water exposure assessments, http //www.waterborne-env.com/modeling/model down-load muscrat.html (accessed January 2, 2007). 

In some cases, mass and energy balances are prepared for multiple scenarios. These might include winter and summer operating conditions, start of catalyst life and end of catalyst life, manufacture of different products or product grades, etc. Usually these different scenarios are shown as several tables on the same flowsheet, but occasionally different flowsheets are drawn for each case. 

The second case study with multiple scenarios in engineering collaboration shows the benefits of using intelligent documents with embedded 3D data implemented in 3D PDF. 

Anonymous, Shell s multiple scenario planning a realistic alternative to the crystal ball. World Business Weekly (1980). 

Giese, H., Klein, E., Burmester, S. Pattern Synthesis from Multiple Scenarios for Parameterized Real-Timed UML Models. In Leue, S., Systa, T.J. (eds.) Scenarios Models, Transformations and Tools. LNCS, vol. 3466, pp. 193-211. Springer, Heidelberg (2005)... 

Other stochastic parameters can also be represented by evaluation of multiple scenarios (e.g., Gutierrez et al. 1996). The obvious limitation of this approach is a limited number of considered scenarios and there is little assurance that the coverage of uncertainty has been adequate. 

It starts with an initiating event (e.g., failure of a component or release of gas, etc.) and generates multiple scenarios. In the event tree, from each branching point, there will be only two paths (basically Y/N). Thus it starts from a single event and then consequences follow a series of possible paths, each of which is assigned a probability, and various outcome probabilities can be calculated to... 

Simulation and optimization are key tools for improving the operations of a chemical process. Unfortunately, the results from these tools are only a good as the accuracy and appropriateness of the process model. This paper presents a model of a polymer batch process that has been modified to include safety constraints. These safety constraints are based upon reactor being able to contain an explosion. Based upon this idea, runaway behavior and cooler limitations are incorporated in the process model since they determine the possibility of an explosion. Neither modeling task was simple to include since they relied upon conditional statements, generation of multiple scenarios, and computational complexity from nonlinear equations such as log mean temperature difference. The optimization of the process model with respect to runaway behavior required the analysis of multiple scenarios or parallel simulations for example. These multiple scenarios would describe the effect of runaway reactions at different times from the basic process profile. In the end, the simulation of the process model ran satisfactory and work on the optimization of the model is in process. 

The Test Case has shown that DRM is able to model the stochastic dynamic aspects of an operation with more accuracy than is possible with static methods. Examples are the position and velocity of aircraft as they evolve through time, the stochastic dynamic behaviour of human operators in response to their environment, situation awareness differences between various actors, multiple scenarios that unfold under influence of hazards occurring, environmental changes, events occurring earlier or later than average, etc. 

The simulations based on this model make it possible to compare multiple scenarios on the basis of a group of performance and cost indicators. Consequently, they provide important and reliable decision-making support for maintenance optimisation. 

Decision trees are useful when sequential decisions are made. They force decision makers to carefully consider the assumptions being made. In addition, decision trees incorporate any uncertainty that surrounds the assumptions in the decision-making process. Decision trees are used in many industries where multiple scenarios exist. Lawyers use them to determine whether or not to appeal verdicts oil companies use them to determine whether or not to drill for oil ... 

This method from seismic to simulation exploiting three-dimensional seismic facies and voxelization process opens new perspectives on reservoir model building, multiple scenarios realizations and faster or right time model up>-dating. 

---