Model evaluation

W. B. DeMore and co-workers. Chemical Kinetics and Photochemical Data for Use in Stratospheric Ocyone Modeling Evaluation No. 8, JPL Publ. 87—41, Jet Propulsion Laboratory, Pasadena, Calif., 1987. 

Limited Data First, plant data are limited. Unfortunately, those easiest to obtain are not necessarily the most useful. In many cases, the measurements that are absolutely required for accurate model development are unavailable. For those that are available, the sensitivity of the parameter estimate, model evaluation, and/or subsequent conclusion to a particiilar measurement may be very low. Design or control engineers seldom look at model development as the primaiy reason for placing sensors. Further, because equipment is frequently not operated in the intended region, the sensitive locations in space and time have shifted. Finally, because the cost-effectiveness of measurements can be difficult to justify, many plants are underinstru-mented. 

An additional role of the model evaluation methods is to help in the actual modeling procedure. In principle, an improvement in the accuracy of a model is possible by incorporating the quality criteria into a scoring function being optimized to derive the model in the first place. 

Eortunately, a 3D model does not have to be absolutely perfect to be helpful in biology, as demonstrated by the applications listed above. However, the type of question that can be addressed with a particular model does depend on the model s accuracy. At the low end of the accuracy spectrum, there are models that are based on less than 25% sequence identity and have sometimes less than 50% of their atoms within 3.5 A of their correct positions. However, such models still have the correct fold, and even knowing only the fold of a protein is frequently sufficient to predict its approximate biochemical function. More specifically, only nine out of 80 fold families known in 1994 contained proteins (domains) that were not in the same functional class, although 32% of all protein structures belonged to one of the nine superfolds [229]. Models in this low range of accuracy combined with model evaluation can be used for confirming or rejecting a match between remotely related proteins [9,58]. 

Figure 12 ModBase, a database of comparative protein stracture models. Screenshots of the following ModBase panels are shown A form for searching for the models of a given protein, summary of the search results, summary of the models of a given protein, details about a single model, alignment on which a given model was based, 3D model displayed by RASMOL [237], and a model evaluation by the Prosall profile [217],...

Hansen, D. A., Puckett, K. ]., Jansen, ]. ]., Lusis, M., and Vickery, J. S., The Eulerian Model Evaluation Field Study (EMEFS). Paper 5.1, pp 58-62, in "Preprints, Seventh Joint Conference on Applications of Air Pollution Meteorology with AWMA," Jan. 14-18, 1991, New Orleans. American Meteorological Society, Boston, 1991. 

The second model evaluated was the Lagrangian Photochemical Model LPM (54), a trajectory model. Backward trajectories were first determined so that starting positions could be used which would allow trajectories to reach station locations at the times of measurement. Measured concentrations ranged from 0.20 to 0.26 ppm and estimated concentrations from 0.05 to 0.53 ppm. 

ISCST3 - Industrial Source Complex - Short Term This model is used in more detailed studies of maximum air quality impacts (Phase 3 - Refined Modeling Analysis). The purpose is to compute short term concentration or deposition values, from multiple sources, on specified locations (i.e., receptors). To download the file, click the filename. This is the latest version of the regulatory model ISCST3 (00101) which was released by U.S. EPA on April 27, 2000. The file ISCST.ZIP is 1.60 MB (Executable, Source, Test Cases). You can also download the ISCST3 model evaluation references. 

Model evaluations can represent both success and failure states of systems. 

ERA S Exposure Model Library and Integrated Model Evaluation System... 

Samanta, P. K. et al, Multiple-Sequential Failure Model Evaluation of and Procedures for Human Error Dependency, BNL May 1985. 

Dr. Richard Walentowicz provided the EPA CD-ROM disk entitled Exposure Models Library and Integrated Model Evaluation System" with other reference material. Lester Wittenberg of the Center for Chemical Process Safety, AIChE was particularly helpful in providing a chenncal industry perspective and reference material as was Dr. Steven Arendt of JBF Associates, Inc. Drs. David Hesse of Battelle Columbus Laboratories and Vinod Mubayi of Brookhaven National Laboratory were very helpful in providing material on the chemical consequence codes. 

Weyant, J. P., and Hill, J. N. (1999). "Introduction and Oveiview. In The Costs of the Kyoto Protocol A Multi-Model Evaluation. The Energy Journal (special issue). 

Irving, P. Ed. Acidic deposition State of science and technology. National Acid Precipitation Assessment Program, Washington, DC, 1990. Clark, T.L., Denise, R.L., Seilhop, S.K., Voldner, E.C., Olson, M.P., and Alvo, M. International sulfur desposition model evaluation. Atmospheric Environment Service, Publication No. ARD-87-1, 1987, Downsview, Ontario, Canada. 

Moreover, since the repeating unit in a-type linear polymers is about 7.5 A, according to a molecular model evaluation, the stacks in the starting crystals prefer to have repeating units of a similar length (L). However, L (5.932 A) in 2 OPr-a-dimer crystals is apparently shorter than the favourable distance (—7.5 A). On the other hand, in the 2 OPr-a-dimer-PrOH complex, reactant dimer molecules are separated from each other by a more suitable distance (L = 6.736 A). 

Five health-care models evaluating olanzapine and haloperidol have been published. All five appear to have used the trial of Tollefson et al (1997) as the basis for... 

Most of these models evaluate the effects of drugs on the behaviour of animals when they are exposed to a novel environment. Novelty normally reduces animals exploratory activity but established anti-anxiety drugs consistently increase exploration of, and approaches to, the novel stimulus and reduce the neophobic ( avoidance ) reaction. There are several examples of tests based on this principle (Table 19.2) but two that are widely used are the plus-maze and the social interaction tests. 

NASA Panel for Data Evaluation, "Chemical Kinetic and Hydrochemical Data for Use in Stratospheric Modeling," Evaluation Number 2, JPL Publication 79-27, April 1979. 

Restenosis after angioplasty is a situation where these therapies may find an early application. The current animal models evaluate the formation of atherosclerosis or a neointima in the same accelerated and artificially induced... 

Martin BR, Compton DR, Thomas BF, Prescott WR, Little PJ, Razdan RK, Johnson MR, Melvin LS, Mechoulam R, Ward SJ. Behavioral, biochemical and molecular modeling evaluations of cannabinoid analogs in mice. Pharmacol Biochem Behav 1991 40 471 478. 

The properties of the ET cover and its design are different from those of conventional covers. Because model evaluation should include all of the important elements required in design, this section provides a review of important elements of the ET cover that influence its design and should be evaluated before selecting and using a particular model. The reader may find additional important details in Refs. 4, 8-12, and 42. 

Both of them require at least limited model calibration. They do not stochastically estimate daily climate data for model evaluations or long-term changes in plant nutrient status and the resulting changes in plant growth and water balance. HYDRUS and UNSAT-H would be very useful and accurate if used in research however, they are difficult to use in engineering design of ET landfill covers and provide incomplete estimates of performance. 

The purpose of model evaluation efforts is to determine if an existing model is adequate for design or evaluation of ET landfill covers and to identify its strengths and weaknesses. This purpose is... 

In its simplest form a partitioning model evaluates the distribution of a chemical between environmental compartments based on the thermodynamics of the system. The chemical will interact with its environment and tend to reach an equilibrium state among compartments. Hamaker(l) first used such an approach in attempting to calculate the percent of a chemical in the soil air in an air, water, solids soil system. The relationships between compartments were chemical equilibrium constants between the water and soil (soil partition coefficient) and between the water and air (Henry s Law constant). This model, as is true with all models of this type, assumes that all compartments are well mixed, at equilibrium, and are homogeneous. At this level the rates of movement between compartments and degradation rates within compartments are not considered. 

Heylen, P., van den Mooter, G., Kinget, R., Drug absorption studies of prodrugs esters using the Caco-2 model evaluation of ester hydrolysis and transepithelial transport, Int. J. Pharm. 1998, 166, 45-53. 

Future work on MPI-MCTM should strive to improve parameterisations implemented in the model, because of two reasons a) as a consequence of what was learned from the model evaluation with DDT, and b) more generally to obtain a better representation of key processes, which at least partly are insufficiently validated. 

Moriasi DN, Arnold JG, Van Liew MW, Bingner RL, Harmel RD, Veith TL (2007) Model evaluation guidelines for systematic quantification of accuracy in watershed simulations. Trans ASABE 50(3) 885-900... 

Yilmaz KK, Gupta HV, Wagener T (2008) A process-based diagnostic approach to model evaluation application to the NWS distributed hydrologic model. Water Resour Res 44(9) W09417. doi 10.1029/2007WR006716... 

The calculation procedure for a sliding temperature path is straightforward. In taking a reaction step, the model evaluates the temperature to be attained at the step s end. Since varies from zero to one, temperature at any point in reaction progress is given by,... 

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