Journal articles: 'Calibration Case Study'

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Toledo, Tomer, Haris N. Koutsopoulos, Angus Davol, Moshe E. Ben-Akiva, Wilco Burghout, Ingmar Andréasson, Tobias Johansson, and Christen Lundin. "Calibration and Validation of Microscopic Traffic Simulation Tools: Stockholm Case Study." Transportation Research Record: Journal of the Transportation Research Board 1831, no. 1 (January 2003): 65–75. http://dx.doi.org/10.3141/1831-08.

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The calibration and validation approach and results from a case study applying the microscopic traffic simulation tool MITSIMLab to a mixed urban-freeway network in the Brunnsviken area in the north of Stockholm, Sweden, under congested traffic conditions are described. Two important components of the simulator were calibrated: driving behavior models and travel behavior components, including origin–destination flows and the route choice model. In the absence of detailed data, only aggregate data (i.e., speed and flow measurements at sensor locations) were available for calibration. Aggregate calibration uses simulation output, which is a result of the interaction among all components of the simulator. Therefore, it is, in general, impossible to identify the effect of individual models on traffic flow when using aggregate data. The calibration approach used takes these interactions into account by iteratively calibrating the different components to minimize the deviation between observed and simulated measurements. The calibrated MITSIMLab model was validated by comparing observed and simulated measurements: traffic flows at sensor locations, point-to-point travel times, and queue lengths. A second set of measurements, taken a year after the ones used for calibration, was used at this stage. Results of the validation are presented. Practical difficulties and limitations that may arise with application of the calibration and validation approach are discussed.

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Acuña, Guillermo J., Humberto Ávila, and Fausto A. Canales. "River Model Calibration Based on Design of Experiments Theory. A Case Study: Meta River, Colombia." Water 11, no. 7 (July 5, 2019): 1382. http://dx.doi.org/10.3390/w11071382.

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Numerical models are important tools for analyzing and solving water resources problems; however, a model’s reliability heavily depends on its calibration. This paper presents a method based on Design of Experiments theory for calibrating numerical models of rivers by considering the interaction between different calibration parameters, identifying the most sensitive parameters and finding a value or a range of values for which the calibration parameters produces an adequate performance of the model in terms of accuracy. The method consists of a systematic process for assessing the qualitative and quantitative performance of a hydromorphological numeric model. A 75 km reach of the Meta River, in Colombia, was used as case study for validating the method. The modeling was conducted by using the software package MIKE-21C, a two-dimensional flow model. The calibration is assessed by means of an Overall Weighted Indicator, based on the coefficient of determination of the calibration parameters and within a range from 0 to 1. For the case study, the most significant calibration parameters were the sediment transport equation, the riverbed load factor and the suspended load factor. The optimal calibration produced an Overall Weighted Indicator equal to 0.857. The method can be applied to any type of morphological models.

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Hall, John J., and Robert L. Williams. "Case study: Inertial measurement unit calibration platform." Journal of Robotic Systems 17, no. 11 (November 2000): 623–32. http://dx.doi.org/10.1002/1097-4563(200011)17:11<623::aid-rob4>3.0.co;2-7.

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Walski, Thomas M. "Case Study: Pipe Network Model Calibration Issues." Journal of Water Resources Planning and Management 112, no. 2 (March 1986): 238–49. http://dx.doi.org/10.1061/(asce)0733-9496(1986)112:2(238).

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Kim, Kangjoo, Mary P. Anderson, and Carl J. Bowser. "Model Calibration with Multiple Targets: A Case Study." Ground Water 37, no. 3 (May 1999): 345–51. http://dx.doi.org/10.1111/j.1745-6584.1999.tb01110.x.

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Holt, Robert W., Jeffrey T. Hansberger, and Deborah A. Boehm-Davis. "Improving Rater Calibration in Aviation: A Case Study." International Journal of Aviation Psychology 12, no. 3 (July 2002): 305–30. http://dx.doi.org/10.1207/s15327108ijap1203_7.

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Parisi, Maria Adelaide, Mariapaola Riggio, Chiara Tardini, and Maurizio Piazza. "Rehabilitation of Timber Structures and Seismic Vulnerability: A Case Study." Advanced Materials Research 133-134 (October 2010): 741–46. http://dx.doi.org/10.4028/www.scientific.net/amr.133-134.741.

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Synthetic methods for the diagnosis of structures and particularly for their vulnerability assessment rely on simplified calculations and visual inspection. Their effectiveness strongly depends on an accurate calibration of the procedure by which data are collected. A recent methodology for the seismic vulnerability assessment of timber roofs in historical buildings has been applied to the Thun Castle during a study for its rehabilitation. The purpose was twofold: testing and calibrating the procedure on a heritage structure and estimating the capability of the roof structure to resist seismic action, as required in a zone of low but not negligible seismicity.

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Estienne, F., D. L. Massart, N. Zanier-Szydlowski, and Ph Marteau. "Multivariate calibration with Raman spectroscopic data: a case study." Analytica Chimica Acta 424, no. 2 (December 2000): 185–201. http://dx.doi.org/10.1016/s0003-2670(00)01107-7.

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., Falguni Baliarsingh. "REAL TIME RESERVOIR OPERATION (CALIBRATION PHASE): A CASE STUDY." International Journal of Research in Engineering and Technology 03, no. 09 (September 25, 2014): 239–51. http://dx.doi.org/10.15623/ijret.2014.0309037.

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Parkinson, S., A. P. Longstaff, S. Fletcher, A. Crampton, and P. Gregory. "Automatic planning for machine tool calibration: A case study." Expert Systems with Applications 39, no. 13 (October 2012): 11367–77. http://dx.doi.org/10.1016/j.eswa.2012.03.054.

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Sun, Wenchao, Yuanyuan Wang, Guoqiang Wang, Xingqi Cui, Jingshan Yu, Depeng Zuo, and Zongxue Xu. "Physically based distributed hydrological model calibration based on a short period of streamflow data: case studies in four Chinese basins." Hydrology and Earth System Sciences 21, no. 1 (January 11, 2017): 251–65. http://dx.doi.org/10.5194/hess-21-251-2017.

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Abstract. Physically based distributed hydrological models are widely used for hydrological simulations in various environments. As with conceptual models, they are limited in data-sparse basins by the lack of streamflow data for calibration. Short periods of observational data (less than 1 year) may be obtained from fragmentary historical records of previously existing gauging stations or from temporary gauging during field surveys, which might be of value for model calibration. However, unlike lumped conceptual models, such an approach has not been explored sufficiently for physically based distributed models. This study explored how the use of limited continuous daily streamflow data might support the application of a physically based distributed model in data-sparse basins. The influence of the length of the observation period on the calibration of the widely applied soil and water assessment tool model was evaluated in four Chinese basins with differing climatic and geophysical characteristics. The evaluations were conducted by comparing calibrations based on short periods of data with calibrations based on data from a 3-year period, which were treated as benchmark calibrations of the four basins, respectively. To ensure the differences in the model simulations solely come from differences in the calibration data, the generalized likelihood uncertainty analysis scheme was employed for the automatic calibration and uncertainty analysis. In the four basins, contrary to the common understanding of the need for observations over a period of several years, data records with lengths of less than 1 year were shown to calibrate the model effectively, i.e., performances similar to the benchmark calibrations were achieved. The models of the wet Jinjiang and Donghe basins could be effectively calibrated using a shorter data record (1 month), compared with the dry Heihe and upstream Yalongjiang basins (6 months). Even though the four basins are very different, when using 1-year or 6-month (covering a whole dry season or rainy season) data, the results show that data from wet seasons and wet years are generally more reliable than data from dry seasons and dry years, especially for the two dry basins. The results demonstrated that this idea could be a promising approach to the problem of calibration of physically based distributed hydrological models in data-sparse basins, and findings from the discussion in this study are valuable for assessing the effectiveness of short-period data for model calibration in real-world applications.

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Sousa, Joaquim, Nuno Martinho, João Muranho, and Alfeu Sá Marques. "Leakage Calibration in Water Distribution Networks with Pressure-Driven Analysis: A Real Case Study." Environmental Sciences Proceedings 2, no. 1 (September 6, 2020): 59. http://dx.doi.org/10.3390/environsciproc2020002059.

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Leakage in water distribution networks (WDN) is still a major concern for water companies. In recent years, the scientific community has dedicated some effort to the leakage calibration issue to obtain accurate models. But leakage modelling implies the use of a pressure-driven approach as well as specific data to define the pressure/leakage relationship. This paper presents the calibration process of a real case study WDN model. The process started with pressure step tests, the model was built in WaterNetGen and the leakage calibration process was performed by a simulated annealing algorithm. As illustrated, after calibration the model was able to produce accurate results.

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Seibert, J. "Multi-criteria calibration of a conceptual runoff model using a genetic algorithm." Hydrology and Earth System Sciences 4, no. 2 (June 30, 2000): 215–24. http://dx.doi.org/10.5194/hess-4-215-2000.

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Abstract. Abstract: Calibration of a model against more than one output variable is important for reliable simulations of internal processes. In this study, a genetic algorithm combined with local optimisation was proposed for automatic single- and multi-criteria calibration of the HBV model, a conceptual runoff model. The model and the optimisation algorithm were applied in two catchments with different geology where, in addition to observed runoff, time series of groundwater level data were available. For a theoretical, error-free test case with synthetic data, the optimisation algorithm was usually able to find the true parameter values. For the real-world case, parameter values varied considerably when calibrating against runoff only. However, parameter values were constrained significantly when calibrating against both runoff and groundwater levels. Furthermore, for one of the catchments, the results of the multi-criteria calibration motivated a modification of the model structure. Keywords: Multi-criteria calibration; genetic algorithm; parameter uncertainty; conceptual runoff models; HBV model; groundwater levels

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Kobusch, Michael, and Sascha Eichstädt. "A case study in model-based dynamic calibration of small strain gauge force transducers." ACTA IMEKO 6, no. 1 (April 25, 2017): 3. http://dx.doi.org/10.21014/acta_imeko.v6i1.433.

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<p class="Abstract">Investigations of the model-based dynamic calibration of a small strain gauge force transducer of high bandwidth revealed new challenges for parameter identification. This paper discusses a more generalized mechanical model of the calibration set-up employed taking account of the transducer’s connection to its mechanical environment at both ends. Based on new experimental sine and shock force data, the improved model is studied and its parameters are identified. It is shown that the proposed model is capable of linking the calibration results of both calibration methods to a much better degree. This paper is an extended version of the original contribution to the IMEKO 2015 conference in Prague, Czech Republic.</p>

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Dini, M., and M. Tabesh. "Water distribution network quality model calibration: a case study – Ahar." Water Supply 17, no. 3 (October 27, 2016): 759–70. http://dx.doi.org/10.2166/ws.2016.166.

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In water distribution network calibration of quality models, bulk and wall decay coefficients are considered to be the adjustable parameters. The bulk decay coefficient is usually gained by using a laboratory bottle test method, but the wall decay coefficient is calibrated with field data of residual chlorine at nodes. This paper aims to present a method to adjust the wall decay coefficients of pipes. A metamodelling approach is developed by the combination of an Ant Colony Optimization (ACO) algorithm and an artificial neural network (ANN) with the EPANET simulator. The proposed method is applied on a two-loop test example and real water distribution network. Results showed that the proposed method can increase the speed of solution 58 times more rapidly than the simple method in the two-loop network. In the real network, the classification based on the average flow velocity produced the best results among all categories, and the classification based on material, diameter, and age of pipes produced the best results among the physical criteria. Also, comparison of results between the measured and calculated data for testing data showed an average error of 3.85% and the calibration model gave good performance.

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Lotz, Johannes, Marc Schwalbach, and Uwe Naumann. "A Case Study in Adjoint Sensitivity Analysis of Parameter Calibration." Procedia Computer Science 80 (2016): 201–11. http://dx.doi.org/10.1016/j.procs.2016.05.310.

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Anvari, Bani, Michael G. H. Bell, Panagiotis Angeloudis, and Washington Y. Ochieng. "Calibration and Validation of a Shared Space Model: Case Study." Transportation Research Record: Journal of the Transportation Research Board 2588, no. 1 (January 2016): 43–52. http://dx.doi.org/10.3141/2588-05.

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Royer, Dana L., Lawren Sack, Peter Wilf, Christopher H. Lusk, Gregory J. Jordan, Ülo Niinemets, Ian J. Wright, et al. "Fossil leaf economics quantified: calibration, Eocene case study, and implications." Paleobiology 33, no. 4 (December 2007): 574–89. http://dx.doi.org/10.1666/07001.1.

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Lin, Chin-Hsu, Mark O. Neal, and J. T. Wang. "A case study of FEA-based crash sensing system calibration." International Journal of Vehicle Design 29, no. 3 (2002): 269. http://dx.doi.org/10.1504/ijvd.2002.002013.

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Sao, Davy, Tasuku Kato, Le Hoang Tu, Panha Thouk, Atiqotun Fitriyah, and Chantha Oeurng. "Evaluation of Different Objective Functions Used in the SUFI-2 Calibration Process of SWAT-CUP on Water Balance Analysis: A Case Study of the Pursat River Basin, Cambodia." Water 12, no. 10 (October 17, 2020): 2901. http://dx.doi.org/10.3390/w12102901.

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Many calibration techniques have been developed for the Soil and Water Assessment Tool (SWAT). Among them, the SWAT calibration and uncertainty program (SWAT-CUP) with sequential uncertainty fitting 2 (SUFI-2) algorithm is widely used and several objective functions have been implemented in its calibration process. In this study, eight different objective functions were used in a calibration of stream flow of the Pursat River Basin of Cambodia, a tropical monsoon and forested watershed, to examine their influences on the calibration results, parameter optimizations, and water resources estimations. As results, many objective functions performed better than satisfactory in calibrating the SWAT model. However, different objective functions defined different fitted values and sensitivity rank of the calibrated parameters, except Nash–Sutcliffe efficiency (NSE) and ratio of standard deviation of observations to root mean square error (RSR) which are equivalent and produced quite identical simulation results including parameter sensitivity and fitted parameter values, leading to the same water balance components and water yields estimations. As they generated reasonable fitted parameter values, either NSE or RSR gave better estimation results of annual average water yield and other water balance components such as annual average evapotranspiration, groundwater flow, surface runoff, and lateral flow according to the characteristics of the river basin and the results and data of previous studies. Moreover, either of them was also better in calibrating base flow, falling limb, and overall the entire flow phases of the hydrograph in this area.

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Park, Byungkyu (Brian), and J. D. Schneeberger. "Microscopic Simulation Model Calibration and Validation: Case Study of VISSIM Simulation Model for a Coordinated Actuated Signal System." Transportation Research Record: Journal of the Transportation Research Board 1856, no. 1 (January 2003): 185–92. http://dx.doi.org/10.3141/1856-20.

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Microscopic simulation models have been widely used in both transportation operations and management analyses because simulation is safer, less expensive, and faster than field implementation and testing. While these simulation models can be advantageous to engineers, the models must be calibrated and validated before they can be used to provide meaningful results. However, the transportation profession has not established any formal or consistent guidelines for the development and application of these models. In practice, simulation model–based analyses have often been conducted under default parameter values or bestguessed values. This is mainly due to either difficulties in field data collection or lack of a readily available procedure for simulation model calibration and validation. A procedure was proposed for microscopic simulation model calibration and validation and an example case study is presented with real-world traffic data from Route 50 on Lee Jackson Highway in Fairfax, Virginia. The proposed procedure consisted of nine steps: ( a) measure of effectiveness selection, ( b) data collection, ( c) calibration parameter identification, ( d) experimental design, ( e) run simulation, ( f) surface function development, ( g) candidate parameter set generations, ( h) evaluation, and ( i) validation through new data collection. The case study indicates that the proposed procedure appears to be properly calibrating and validating the VISSIM simulation model for the test-bed network.

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Kumar, Uttam, Julien Morel, Göran Bergkvist, Taru Palosuo, Anne-Maj Gustavsson, Allan Peake, Hamish Brown, Mukhtar Ahmed, and David Parsons. "Comparative Analysis of Phenology Algorithms of the Spring Barley Model in APSIM 7.9 and APSIM Next Generation: A Case Study for High Latitudes." Plants 10, no. 3 (February 26, 2021): 443. http://dx.doi.org/10.3390/plants10030443.

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Phenology algorithms in crop growth models have inevitable systematic errors and uncertainties. In this study, the phenology simulation algorithms in APSIM classical (APSIM 7.9) and APSIM next generation (APSIM-NG) were compared for spring barley models at high latitudes. Phenological data of twelve spring barley varieties were used for the 2014–2018 cropping seasons from northern Sweden and Finland. A factorial-based calibration approach provided within APSIM-NG was performed to calibrate both models. The models have different mechanisms to simulate days to anthesis. The calibration was performed separately for days to anthesis and physiological maturity, and evaluations for the calibrations were done with independent datasets. The calibration performance for both growth stages of APSIM-NG was better compared to APSIM 7.9. However, in the evaluation, APSIM-NG showed an inclination to overestimate days to physiological maturity. The differences between the models are possibly due to slower thermal time accumulation mechanism, with higher cardinal temperatures in APSIM-NG. For a robust phenology prediction at high latitudes with APSIM-NG, more research on the conception of thermal time computation and implementation is suggested.

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Yi, P., and Y. Chan. "Bifurcation and Disaggregation in Lowry—Garin Derivative Models: Theory, Calibration, and Case Study." Environment and Planning A: Economy and Space 20, no. 9 (September 1988): 1253–67. http://dx.doi.org/10.1068/a201253.

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The classic Lowry—Garin model is reexamined in light of advances in bifurcation theory and disaggregate model calibration techniques. A procedure for disaggregate calibration of the multipliers used in the economic-base component of the model is presented. Also given is an endogenous calibration procedure to include zonal constraints into the spatial interaction part of the unconstrained Lowry—Garin model. This is accomplished through the use of only two simple parameters which have important physical interpretations regarding the sensitivity of transportation improvements. Bifurcation conditions are then specified for the constrained model in both the aggregate and disaggregate cases. Through a case study of a medium-size city, the disaggregate calibration approach was found to produce better replication of the observed development pattern. Also the endogenous way of embedding zonal constraints in the two aforementioned parameters was found to be extremely efficient computationally. Most importantly, the analytical framework offers a transparent way of explaining urban development, including the prediction of precipitous developments, thus relieving much of the burden of traditional simulation approaches which tend to be cumbersome and analytically intractable.

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Meza, Ramses G., Juan M. Florez, Stanislav Kuzmin, and John P. Castagna. "Quantitative assessment of the seismic net-pay method: A case study." Interpretation 3, no. 2 (May 1, 2015): B25—B36. http://dx.doi.org/10.1190/int-2014-0241.1.

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We applied the seismic net-pay (SNP) method to an oil discovery and predicted thicknesses consistent with the actual thicknesses at the wellbore locations. This was accomplished by applying the method in a self-calibrating mode that did not require the direct use of well information. For net-pay estimation under a self-calibration scenario, the SNP method thickness estimates proved to be more accurate (mean absolute prediction error at well validation locations under [Formula: see text]) than estimates from a reflectivity-based detuning method ([Formula: see text]) or multiple linear regression ([Formula: see text]). Statistical [Formula: see text]-tests indicated that the correspondences of the predicted thickness estimates with actual net-pay values for the SNP and reflectivity methods (F approximately 5.5–6 for both) were statistically significant, whereas the multiple regression results did not prove to be statistically significant.

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Sendra, J. J., T. Blázquez, and R. Suárez. "Towards a calibration of building energy models: A case study from the Spanish housing stock in the Mediterranean climate." Informes de la Construcción 67, no. 540 (December 16, 2015): e128. http://dx.doi.org/10.3989/ic.15.081.

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Heinkelé, C., M. Labbé, V. Muzet, and P. Charbonnier. "CALIBRATION OF THE SR4500 TIME-OF-FLIGHT CAMERA FOR OUTDOOR MOBILE SURVEYING APPLICATIONS: A CASE STUDY." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B5 (June 15, 2016): 469–76. http://dx.doi.org/10.5194/isprsarchives-xli-b5-469-2016.

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3D-cameras based on Time-of-Flight (ToF) technology have recently raised up to a commercial level of development. In this contribution, we investigate the outdoor calibration and measurement capabilities of the SR4500 ToF camera. The proposed calibration method combines up-to-date techniques with robust estimation. First, intrinsic camera parameters are estimated, which allows converting radial distances into orthogonal ones. The latter are then calibrated using successive acquisitions of a plane at different camera positions, measured by tacheometric techniques. This distance calibration step estimates two coefficient matrices for each pixel, using linear regression. Experimental assessments carried out with a 3D laser-cloud after converting all the data in a common basis show that the obtained precision is twice better than with the constructor default calibration, with a full-frame accuracy of about 4 cm. Moreover, estimating the internal calibration in sunny and warm outdoor conditions yields almost the same coefficients as indoors. Finally, a test shows the feasibility of dynamic outdoor acquisitions and measurements.

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Heinkelé, C., M. Labbé, V. Muzet, and P. Charbonnier. "CALIBRATION OF THE SR4500 TIME-OF-FLIGHT CAMERA FOR OUTDOOR MOBILE SURVEYING APPLICATIONS: A CASE STUDY." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B5 (June 15, 2016): 469–76. http://dx.doi.org/10.5194/isprs-archives-xli-b5-469-2016.

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3D-cameras based on Time-of-Flight (ToF) technology have recently raised up to a commercial level of development. In this contribution, we investigate the outdoor calibration and measurement capabilities of the SR4500 ToF camera. The proposed calibration method combines up-to-date techniques with robust estimation. First, intrinsic camera parameters are estimated, which allows converting radial distances into orthogonal ones. The latter are then calibrated using successive acquisitions of a plane at different camera positions, measured by tacheometric techniques. This distance calibration step estimates two coefficient matrices for each pixel, using linear regression. Experimental assessments carried out with a 3D laser-cloud after converting all the data in a common basis show that the obtained precision is twice better than with the constructor default calibration, with a full-frame accuracy of about 4 cm. Moreover, estimating the internal calibration in sunny and warm outdoor conditions yields almost the same coefficients as indoors. Finally, a test shows the feasibility of dynamic outdoor acquisitions and measurements.

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Härdle, Wolfgang Karl, and Brenda López Cabrera. "Calibration of Parametric CAT Bonds. A Case Study of Mexican Earthquakes." Schmollers Jahrbuch 128, no. 4 (December 2008): 615–30. http://dx.doi.org/10.3790/schm.128.4.615.

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Cogdill, Robert P., Carl A. Anderson, and James K. Drennen. "Process analytical technology case study, part III: Calibration monitoring and transfer." AAPS PharmSciTech 6, no. 2 (June 2005): E284—E297. http://dx.doi.org/10.1208/pt060239.

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Ferens, Daniel V., and David S. Christensen. "Software Cost Model Calibration and Validation—An Air Force Case Study." Journal of Cost Analysis 14, no. 2 (November 1997): 43–56. http://dx.doi.org/10.1080/08823871.1997.10462312.

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Rogne, Bryan, Todd Gebert, Jennifer Hurlebaus, and Mike Agbodo. "CALIBRATION TECHNIQUES FOR MODELING COMPLEX SYSTEMS – A MADISON, WISCONSIN CASE STUDY." Proceedings of the Water Environment Federation 2005, no. 6 (January 1, 2005): 8737–60. http://dx.doi.org/10.2175/193864705783812738.

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Gebert, Todd, Jennifer Hurlebaus, Bryan Rogne, and Mike Agbodo. "Calibration Techniques for Modeling Complex Systems - A Madison, Wisconsin Case Study." Proceedings of the Water Environment Federation 2005, no. 4 (January 1, 2005): 519–42. http://dx.doi.org/10.2175/193864705784291501.

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Zeng, Qiaoling Charlene, Elizabeth Zhang, and Joel Tellinghuisen. "Univariate calibration by reversed regression of heteroscedastic data: a case study." Analyst 133, no. 12 (2008): 1649. http://dx.doi.org/10.1039/b808667b.

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Noriega-Hevia, G., O. Mateo, A. Maciá, C. Lardín, L. Pastor, J. Serralta, and A. Bouzas. "Experimental sulphide inhibition calibration method in nitrification processes: A case-study." Journal of Environmental Management 274 (November 2020): 111191. http://dx.doi.org/10.1016/j.jenvman.2020.111191.

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Zhang, Danrong, Liru Zhang, Yiqing Guan, Xi Chen, and Xinfang Chen. "Sensitivity analysis of Xinanjiang rainfall–runoff model parameters: a case study in Lianghui, Zhejiang province, China." Hydrology Research 43, no. 1-2 (February 1, 2012): 123–34. http://dx.doi.org/10.2166/nh.2011.131.

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The Xinanjiang rainfall–runoff model has been successfully applied in many humid and sub-humid areas in China since 1973. The wide application is due to the simple model structure, the clear physical meaning of the parameters and the well-defined model calibration procedure. However, due to a data scarcity problem and short runoff concentration time, its applications to small drainage basins are difficult. Therefore, we investigate the model application in Lianghui, a small drainage basin of Zhejiang province in China. By using generalized likelihood uncertainty estimation (GLUE) methodology, the sensitivity of parameters of Xinanjiang model was investigated. The data clearly showed that equifinality phenomenon was evident in both water balance parameter calibration and runoff routing parameter calibration procedures. The results showed that K (evapotranspiration conversion coefficient), Cs (recession constant in channel system) and Sm (areal free water storage capacity of surface soil) are the most sensitive parameters for the water balance parameter calibration while Cs, Sm and Wm (mean area tension water capacity) are the most sensitive parameters for runoff routing parameter calibration. The conclusion is favourable for understanding parameters of Xinanjiang model in order to provide valuable scientific information for simulating hydrological processes in small drainage basins.

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Quadir, Kamila Afroj, Brian Zimmermann, Md Nahid Hossain, Md Nurul Islam, Ferdoushi Begum, Tanvir Ahmed Biman, and Mohammad Anwar Ul Azim. "Quantification of Patient Specific Dosimetry in Radionuclide Therapy: A Phantom Study." Bangladesh Journal of Nuclear Medicine 17, no. 2 (June 14, 2016): 134–37. http://dx.doi.org/10.3329/bjnm.v17i2.28199.

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The accuracy of patient specific dosimetry is correlated with measured organ activity by gamma camera and SPECT system. The assessment of the radiation-absorbed dose by patients undergoing nuclear medicine investigation requires accurate measurement of organ activity, biokinetics data, as well as physical data. Activities were estimated by using Ba-133 phantom with both planar and SPECT systems. The objective of the study was to measure the activities of Ba-133 from gamma camera images using both planar and SPECT studies and compare the reference values with the dose calibrator values to quantify the actual activity with gamma camera. Four Ba-133 sources of different volume and activity 379, 950, 1219 and 1150 KBq are measured by using Veenstra Instrument VDC 404 Dose Calibrator. The second smallest source was used to determine the calibration factor. Acquisition, corrections, reconstruction, quantification and measuring activity from both planar and SPECT imaging were done with all Ba-133 sources in air. The activities of the Ba-133 sources were also measured using I-131 settings of the dose calibrator. The measurement of the second smallest source was used to obtain the calibration factor. This calibration factor was used to convert the planer and SPECT image count of all the sources into activities. In case of both planar and SPECT gamma camera, the measurements showed good correlations and all the values varied within ±15%. Planer and SPECT gamma camera image counts can be used to calculate activity in the organ. This information can play a very significant role in evaluating image based patient specific dosimetry in radionuclide therapy.Bangladesh J. Nuclear Med. 17(2): 134-137, July 2014

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Kim, JungJin, and Jae Ryu. "Quantifying the Performances of the Semi-Distributed Hydrologic Model in Parallel Computing—A Case Study." Water 11, no. 4 (April 19, 2019): 823. http://dx.doi.org/10.3390/w11040823.

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The research features how parallel computing can advance hydrological performances associated with different calibration schemes (SCOs). The result shows that parallel computing can save up to 90% execution time, while achieving 81% simulation improvement. Basic statistics, including (1) index of agreement (D), (2) coefficient of determination (R2), (3) root mean square error (RMSE), and (4) percentage of bias (PBIAS) are used to evaluate simulation performances after model calibration in computer parallelism. Once the best calibration scheme is selected, additional efforts are made to improve model performances at the selected calibration target points, while the Rescaled Adjusted Partial Sums (RAPS) is used to evaluate the trend in annual streamflow. The qualitative result of reducing execution time by 86% on average indicates that parallel computing is another avenue to advance hydrologic simulations in the urban-rural interface, such as the Boise River Watershed, Idaho. Therefore, this research will provide useful insights for hydrologists to design and set up their own hydrological modeling exercises using the cost-effective parallel computing described in this case study.

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Sparnaaij, Martijn, Dorine C. Duives, Victor L. Knoop, and Serge P. Hoogendoorn. "Multiobjective Calibration Framework for Pedestrian Simulation Models: A study on the Effect of Movement Base Cases, Metrics, and Density Levels." Journal of Advanced Transportation 2019 (July 3, 2019): 1–18. http://dx.doi.org/10.1155/2019/5874085.

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Ideally, a multitude of steps has to be taken before a commercial implementation of a pedestrian model is used in practice. Calibration, the main goal of which is to increase the accuracy of the predictions by determining the set of values for the model parameters that allows for the best replication of reality, has an important role in this process. Yet, up to recently, calibration has received relatively little attention within the field of pedestrian modelling. Most studies focus only on one specific movement base case and/or use a single metric. It is questionable how generally applicable a pedestrian simulation model is that has been calibrated using a limited set of movement base cases and one metric. The objective of this research is twofold, namely, to (1) determine the effect of the choice of movement base cases, metrics, and density levels on the calibration results and (2) to develop a multiple-objective calibration approach to determine the aforementioned effects. In this paper a multiple-objective calibration scheme is presented for pedestrian simulation models, in which multiple normalized metrics (i.e., flow, spatial distribution, effort, and travel time) are combined by means of weighted sum method that accounts for the stochastic nature of the model. Based on the analysis of the calibration results, it can be concluded that (1) it is necessary to use multiple movement base cases when calibrating a model to capture all relevant behaviours, (2) the level of density influences the calibration results, and (3) the choice of metric or combinations of metrics influence the results severely.

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Wang, Jiali, Cheng Wang, Vishwas Rao, Andrew Orr, Eugene Yan, and Rao Kotamarthi. "A parallel workflow implementation for PEST version 13.6 in high-performance computing for WRF-Hydro version 5.0: a case study over the midwestern United States." Geoscientific Model Development 12, no. 8 (August 13, 2019): 3523–39. http://dx.doi.org/10.5194/gmd-12-3523-2019.

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Abstract. The Weather Research and Forecasting Hydrological (WRF-Hydro) system is a state-of-the-art numerical model that models the entire hydrological cycle based on physical principles. As with other hydrological models, WRF-Hydro parameterizes many physical processes. Hence, WRF-Hydro needs to be calibrated to optimize its output with respect to observations for the application region. When applied to a relatively large domain, both WRF-Hydro simulations and calibrations require intensive computing resources and are best performed on multimode, multicore high-performance computing (HPC) systems. Typically, each physics-based model requires a calibration process that works specifically with that model and is not transferrable to a different process or model. The parameter estimation tool (PEST) is a flexible and generic calibration tool that can be used in principle to calibrate any of these models. In its existing configuration, however, PEST is not designed to work on the current generation of massively parallel HPC clusters. To address this issue, we ported the parallel PEST to HPCs and adapted it to work with WRF-Hydro. The porting involved writing scripts to modify the workflow for different workload managers and job schedulers, as well as to connect the parallel PEST to WRF-Hydro. To test the operational feasibility and the computational benefits of this first-of-its-kind HPC-enabled parallel PEST, we developed a case study using a flood in the midwestern United States in 2013. Results on a problem involving the calibration of 22 parameters show that on the same computing resources used for parallel WRF-Hydro, the HPC-enabled parallel PEST can speed up the calibration process by a factor of up to 15 compared with commonly used PEST in sequential mode. The speedup factor is expected to be greater with a larger calibration problem (e.g., more parameters to be calibrated or a larger size of study area).

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de Oliveira, Antonio Krishnamurti Beleño, Osvaldo Moura Rezende, Matheus Martins de Sousa, Andrea Nardini, and Marcelo Gomes Miguez. "An alternative flood model calibration strategy for urban watersheds: the case study of Riohacha, Colombia." Water Science and Technology 79, no. 11 (June 1, 2019): 2095–105. http://dx.doi.org/10.2166/wst.2019.211.

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Abstract The city of Riohacha (Colombia) has a complex urban setting that, under the pressure of recurring intense rains, experiences increasing flood damage. With the aim of identifying a systemic solution to flood problems, a hydrodynamic mathematical modelling exercise was conducted. Within the modelling process, calibration and validation are two fundamental actions that must precede the use of the model. However, most of the river basins around the world lack hydrometeorological information, which is indispensable for the calibration process. This paper presents an original approach to collecting such information for the calibration process, based on interviewing inhabitants. The results of this effort were surprisingly good, when considering the kind of approximations involved in using people's answers as hard data. This encouraged us to promote it as a working solution for many other similar cases, which all suffer from lack of suitable data.

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Ho, Simon Y. W., Greger Larson, Ceiridwen J. Edwards, Tim H. Heupink, Kay E. Lakin, Peter W. H. Holland, and Beth Shapiro. "Correlating Bayesian date estimates with climatic events and domestication using a bovine case study." Biology Letters 4, no. 4 (April 17, 2008): 370–74. http://dx.doi.org/10.1098/rsbl.2008.0073.

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The tribe Bovini contains a number of commercially and culturally important species, such as cattle. Understanding their evolutionary time scale is important for distinguishing between post-glacial and domestication-associated population expansions, but estimates of bovine divergence times have been hindered by a lack of reliable calibration points. We present a Bayesian phylogenetic analysis of 481 mitochondrial D-loop sequences, including 228 radiocarbon-dated ancient DNA sequences, using a multi-demographic coalescent model. By employing the radiocarbon dates as internal calibrations, we co-estimate the bovine phylogeny and divergence times in a relaxed-clock framework. The analysis yields evidence for significant population expansions in both taurine and zebu cattle, European aurochs and yak clades. The divergence age estimates support domestication-associated expansion times (less than 12 kyr) for the major haplogroups of cattle. We compare the molecular and palaeontological estimates for the Bison – Bos divergence.

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Gumiere, Silvio Jose, Laurence Delattre, Yves Le Bissonnais, Bruno Cheviron, Abir Ben Slimane, and Damien Raclot. "Multi-scale Calibration and Validation of MHYDAS-Erosion for A Small Mediterranean Vineyard Catchment: A Case Study." Revue des sciences de l’eau 27, no. 1 (January 29, 2014): 21–36. http://dx.doi.org/10.7202/1021980ar.

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Abstract In this work we present a case study of the multi-scale calibration and validation of MHYDAS-Erosion applied to a Mediterranean vineyard. The calibration was performed using expert knowledge in linking physical parameters to land uses with the automatic parameter estimation software PEST. MHYDAS-Erosion was calibrated and validated using spatially distributed observations on total discharge and soil loss. Calibration has been performed within six rainfall events; both hydrological and erosion parameters were calibrated using RMSE, R2 and the modified version of the Nash-Sutcliffe model efficiency criteria. Calibration results indicate there was good agreement between simulated and observed total discharge and total soil loss at the seven observation points (modified Nash-Sutcliffe efficiency (mNSE) ranging between 0.89 and 0.95). Acceptable results were obtained in terms of parameter values, identification of their physical meaning and coherence. However, some limitations were also identified, and could be remedied in more detailed studies involving (i) spatially-distributed rainfall on the catchment, (ii) a description of groundwater exfiltration and (iii) spatially-distributed properties of the ditches over the catchment. Validation results were quite satisfactory for three of the four validation events. The results from this case study suggest that MHYDAS-Erosion may need a specific calibration when applied to another catchment, but once it is calibrated, it could be used for multi-scale soil loss forecasting.

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Pérez-Sánchez, Modesto, Francisco J. Sánchez-Romero, Helena M. Ramos, and P. Amparo López-Jiménez. "Calibrating a flow model in an irrigation network: Case study in Alicante, Spain." Spanish Journal of Agricultural Research 15, no. 1 (April 20, 2017): e1202. http://dx.doi.org/10.5424/sjar/2017151-10144.

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The usefulness of models depends on their validation in a calibration process, ensuring that simulated flows and pressure values in any line are really occurring and, therefore, becoming a powerful decision tool for many aspects in the network management (i.e., selection of hydraulic machines in pumped systems, reduction of the installed power in operation, analysis of theoretical energy recovery). A new proposed method to assign consumptions patterns and to determine flows over time in irrigation networks is calibrated in the present research. As novelty, the present paper proposes a robust calibration strategy for flow assignment in lines, based on some key performance indicators (KPIF) coming from traditional hydrological models: Nash-Sutcliffe coefficient (non-dimensional index), root relative square error (error index) and percent bias (tendency index). The proposed strategy for calibration was applied to a real case in Alicante (Spain), with a goodness of fit considered as “very good” in many indicators. KPIF parameters observed present a satisfactory goodness of fit of the series, considering their repeatability. Average Nash-Sutcliffe coefficient value oscillated between 0.30 and 0.63, average percent bias values were below 10% in all the range, and average root relative square error values varied between 0.65 and 0.80.

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Sowinski, Marek, and Anna Neugebauer. "CALIBRATION OF WATER‐QUALITY MODEL “WODA” – CASE STUDY OF THE WARTA RIVER." JOURNAL OF ENVIRONMENTAL ENGINEERING AND LANDSCAPE MANAGEMENT 15, no. 2 (June 30, 2007): 93–98. http://dx.doi.org/10.3846/16486897.2007.9636914.

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The main feature of the proposed model implemented by a computer package WODA, that distinguishes it from other commonly used models like QUALE 2E or WASP5, is a possibility of its automatic calibration i e parameter estimation taking into account simultaneously several sets of measured concentration data. Model WODA, developed by A. Kraszewski and R. Soncini‐Sessa, enables fitting simulated values to measured concentrations of BOD and DO based on the least‐square criterion. This model was applied for parameter estimation of the Warta River in Poland. Measured concentration data used for parameter estimation were obtained from monthly monitoring. The results are presented in the form of BOD and DO lines against measured concentrations along the analysed stretch of the Warta River. Adaptation of the model simulation results to measured data is described by quantifying characteristics. They indicate relatively good adjustment. The reasons of some differences are discussed and explained.

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Jakic, Nina, Kristina Kiesel, and Ardeshir Mahdavi. "Exploring the Potential of Simulation Model Calibration an Acoustical Retrofit Case Study." Applied Mechanics and Materials 887 (January 2019): 561–68. http://dx.doi.org/10.4028/www.scientific.net/amm.887.561.

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The success of gastronomic facilities is due, not in a small part, to perceived indoor atmosphere. This includes not just the interior design but also lighting and acoustics. Especially acoustics is a crucial parameter concerning the perception of the environment, but it is often neglected. The present case study investigates the usability and accuracy of acoustics simulation as applied to the retrofit project of a restaurant. The restaurant space was modelled in CAD-based modelling environment. Subsequently, acoustical simulations based on ray tracing were conducted and the simulation model was calibrated based on on-site measurements of the reverberation time. The initial simulation showed large deviations from the measured values, mainly because of uncertainties in the input data concerning the absorption properties of the used materials. Within three calibration steps, the model was revised, such that better results could be achieved. Subsequently both the initial and the calibrated models were used to develop strategies for the improvement of the acoustical performance of the space. After the implementation of the new design options in the restaurant, measurements were repeated. Again the results were compared with both the initial and the calibrated model. The results suggest that the calibrated model displayed a better performance regarding the prediction of post-retrofit circumstances when compared to the non-calibrated one.

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Bulhões, Frank Cenci, Gleidson Diniz Ferreira, and José Fernando Caparica Jr. "IMPACTS OF SEISMIC VELOCITY MODEL CALIBRATION FOR TIME-DEPTH CONVERSION:A CASE STUDY." Revista Brasileira de Geofísica 36, no. 4 (December 21, 2018): 1. http://dx.doi.org/10.22564/rbgf.v36i4.1965.

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ABSTRACT. In this work we discuss the impact of the uncertainties in the seismic interpretation on the velocity model building and time-depth conversion. The case study presented is located in the Campos Basin, Brazil. The main objective of this work is to show how the input data and the parameters affect substantially the velocity modeling. The methodology uses velocity model building methods and calibration parameters to integrate seismic interpretation and wells. It presents scenarios with calibration by time-depth tables and horizons-geological markers. The data converted to depth are compared to the time data and the geological markers. The data converted by the calibrated model with horizon-marker presented smaller differences compared to the markers and lower correlations in the pseudo-impedance. In the time-depth table calibration scenarios, the differences of the horizons compared to the markers were higher, but in the range of the seismic resolution and higher correlations.Keywords: seismic migration; wells; geological markers; exploration; interpretation.RESUMO. Neste trabalho é apresentado como as incertezas na interpretação sísmica impactam na cons-trução do modelo de velocidades e na conversão tempo-profundidade resultante. A área de estudo de estudo está localizada na Bacia de Campos, Brasil. O principal objetivo deste trabalho é mostrar como os dados de entrada e parâmetros afetam na modelagem de velocidade e conversão tempo x profundidade. A metodologia é comparar três diferentes cenários para calibração da velocidade de processamento e imageamento com as interpretações sísmicas e de poços: o cenário 1 utiliza ajuste por horizonte com marcador geológico e raio de influência 5 km; no cenário 2 é utilizada as tabelas tempo-profundidade, raio de influência 5 km por krigagem com derivada externa; e o cenário 3 utilizou-se tabelas tempo-profundidade, raio de influência 2 km por krigagem com deriva externa. O controle de qualidade dos três modelos de velocidade são avaliados pela conversão dos horizontes, seções sísmicas e perfis de pseudo-impedância. No cenário 1, os horizontes convertidos apresentam menores diferenças de profundidade em relação aos marcadores comparados aos demais cenários. Por outro lado, os cenários 2 e 3 apresentam maiores correlações entre o sismograma sintético e a seção sísmica convertida para o cenário 1.Palavras-chave: migração sísmica; poços; marcadores geológicos; exploração; interpretação.

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Tommaselli, A. M. G., A. Berveglieri, R. A. Oliveira, L. Y. Nagai, and E. Honkavaara. "ORIENTATION AND CALIBRATION REQUIREMENTS FOR HYPERPECTRAL IMAGING USING UAVs: A CASE STUDY." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-3/W4 (March 17, 2016): 109–15. http://dx.doi.org/10.5194/isprsarchives-xl-3-w4-109-2016.

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Flexible tools for photogrammetry and remote sensing using unmanned airborne vehicles (UAVs) have been attractive topics of research and development. The lightweight hyperspectral camera based on a Fabry-Pérot interferometer (FPI) is one of the highly interesting tools for UAV based remote sensing for environmental and agricultural applications. The camera used in this study acquires images from different wavelengths by changing the FPI gap and using two CMOS sensors. Due to the acquisition principle of this camera, the interior orientation parameters (IOP) of the spectral bands can vary for each band and sensor and changing the configuration also would change these sets of parameters posing an operational problem when several bands configurations are being used. The objective of this study is to assess the impact of use IOPs estimated for some bands in one configuration for other bands of different configuration the FPI camera, considering different IOP and EOP constraints. The experiments were performed with two FPI-hyperspectral camera data sets: the first were collected 3D terrestrial close-range calibration field and the second onboard of an UAV in a parking area in the interior of São Paulo State.

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Cheng, Jie, Xinmiao Yang, Wei Deng, and Xin Huang. "Driver's critical gap calibration at urban roundabouts: A case study in China." Tsinghua Science and Technology 13, no. 2 (April 2008): 237–42. http://dx.doi.org/10.1016/s1007-0214(08)70038-5.

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Bartin, Bekir, Kaan Ozbay, Jingqin Gao, and Abdullah Kurkcu. "Calibration and validation of large-scale traffic simulation networks: a case study." Procedia Computer Science 130 (2018): 844–49. http://dx.doi.org/10.1016/j.procs.2018.04.076.

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Tommaselli, A. M. G., A. Berveglieri, R. A. Oliveira, L. Y. Nagai, and E. Honkavaara. "ORIENTATION AND CALIBRATION REQUIREMENTS FOR HYPERPECTRAL IMAGING USING UAVs: A CASE STUDY." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-3/W4 (March 17, 2016): 109–15. http://dx.doi.org/10.5194/isprs-archives-xl-3-w4-109-2016.

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Flexible tools for photogrammetry and remote sensing using unmanned airborne vehicles (UAVs) have been attractive topics of research and development. The lightweight hyperspectral camera based on a Fabry-Pérot interferometer (FPI) is one of the highly interesting tools for UAV based remote sensing for environmental and agricultural applications. The camera used in this study acquires images from different wavelengths by changing the FPI gap and using two CMOS sensors. Due to the acquisition principle of this camera, the interior orientation parameters (IOP) of the spectral bands can vary for each band and sensor and changing the configuration also would change these sets of parameters posing an operational problem when several bands configurations are being used. The objective of this study is to assess the impact of use IOPs estimated for some bands in one configuration for other bands of different configuration the FPI camera, considering different IOP and EOP constraints. The experiments were performed with two FPI-hyperspectral camera data sets: the first were collected 3D terrestrial close-range calibration field and the second onboard of an UAV in a parking area in the interior of São Paulo State.

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Journal articles on the topic 'Calibration Case Study'

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