Journal articles: 'Loads estimation'

1

Lythe, G. R., and D. Surry. "Wind-induced torsional loads on buildings." Canadian Journal of Civil Engineering 19, no. 4 (August 1, 1992): 711–23. http://dx.doi.org/10.1139/l92-079.

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This paper examines the mean and peak torsional wind loads on tall buildings using two data bases of torsion measured experimentally in wind tunnel tests: the first, a large data base of mean torsional loads; and the second, a smaller data base of peak torsions. Although the mean load constitutes only a part of the total peak load required for design, it provides considerable insight into the aerodynamics of torsion, while improvement in its estimation also improves the estimation of the total peak load, using empirical gust factor methods. Comparisons between experimental results and the corresponding provisions of the 1985 National Building Code of Canada and Commentary indicate that, while the NBCC is a good estimator of mean shear loads, it significantly underestimates the mean torsional loads on tall buildings. The experimental data are further analysed to provide an improved estimation method for both the mean and the peak torsion. For mean torsion, this involves evaluating various definitions of the torsion coefficient and classifying building shapes in order to decrease the variability of the associated coefficients. This process leads to some notion of those shapes susceptible to large torsional loads and the most important building parameters on which to base predictions. This insight, along with the data base of peak torsion, is used to simplify and improve an existing method for estimating peak torsion, which was developed using a smaller data base. Key words: torsion, wind loading, codes, wind tunnel tests, tall buildings.

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Rao, Zhushi, Qinzhong Shi, and Ichiro Hagiwara. "Optimal Estimation of Dynamic Loads for Multiple-Input System." Journal of Vibration and Acoustics 121, no. 3 (July 1, 1999): 397–401. http://dx.doi.org/10.1115/1.2893993.

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An optimal method is developed to estimate the dynamic loads for systems subjected to multiple inputs. The method focuses on minimizing the ensemble mean square error of the estimation. First, the inverse system analysis technique is employed to establish the error estimation equation. Then, by applying the noncausal Wiener filtering theory, the optimal estimator of dynamic loads is derived out. Numerical simulation work demonstrates that the method is of a good ability in suppressing the influence of measurement noises on estimation accuracy. Meanwhile, the simulating calculation of load estimation by a conventional method is also performed and the comparison of both results shows that the method proposed in this paper is rather effective and practicable for dynamic load estimation.

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Deesomsuk, Teerachai, and Tospol Pinkaew. "Effectiveness of Vehicle Weight Estimation from Bridge Weigh-in-Motion." Advances in Civil Engineering 2009 (2009): 1–13. http://dx.doi.org/10.1155/2009/312034.

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The effectiveness of vehicle weight estimations from bridge weigh-in-motion system is studied. The measured bending moments of the instrumented bridge under a passage of vehicle are numerically simulated and are used as the input for the vehicle weight estimations. Two weight estimation methods assuming constant magnitudes and time-varying magnitudes of vehicle axle loads are investigated. The appropriate number of bridge elements and sampling frequency are considered. The effectiveness in term of the estimation accuracy is evaluated and compared under various parameters of vehicle-bridge system. The effects of vehicle speed, vehicle configuration, vehicle weight and bridge surface roughness on the accuracy of the estimated vehicle weights are intensively investigated. Based on the obtained results, vehicle speed, surface roughness level and measurement error seem to have stronger effects on the weight estimation accuracy than other parameters. In general, both methods can provide quite accurate weight estimation of the vehicle. Comparing between them, although the weight estimation method assuming constant magnitudes of axle loads is faster, the method assuming time-varying magnitudes of axle loads can provide axle load histories and exhibits more accurate weight estimations of the vehicle for almost of the considered cases.

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Rajani, B., and C. Zhan. "On the estimation of frost loads." Canadian Geotechnical Journal 33, no. 4 (August 20, 1996): 629–41. http://dx.doi.org/10.1139/t96-088-309.

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Frost load is an important loading condition to consider for the design of buried pipes. Though frost loads can be much greater than earth loads, it is not presently possible to estimate frost loads except using heuristic arguments. This paper describes the development of simplified methods to estimate frost load. Important variables are identified that can explain how the effects of frost loading can be mitigated. Sensitivity analyses are presented to highlight the importance of the different variables involved in the simplified methods. Frost loads measured in a field case study are compared with calculated frost loads in trenches with clay and sand backfills. Key words: frost load, frost depth, buried pipe, trench backfills, trench width.

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Yamamoto, K., and T. Suetsugi. "Estimation of particulate nutrient load usingturbidity meter." Water Science and Technology 53, no. 2 (January 1, 2006): 311–20. http://dx.doi.org/10.2166/wst.2006.065.

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The “Nutrient Load Hysteresis Coefficient” was proposed to evaluate the hysteresis of the nutrient loads to flow rate quantitatively. This could classify the runoff patterns of nutrient load into 15 patterns. Linear relationships between the turbidity and the concentrations of particulate nutrients were observed. It was clarified that the linearity was caused by the influence of the particle size on turbidity output and accumulation of nutrients on smaller particles (diameter <23 μm). The L-Q-Turb method, which is a new method for the estimation of runoff loads of nutrients using a regression curve between the turbidity and the concentrations of particulate nutrients, was developed. This method could raise the precision of the estimation of nutrient loads even if they had strong hysteresis to flow rate. For example, as for the runoff load of total phosphorus load on flood events in a total of eight cases, the averaged error of estimation of total phosphorus load by the L-Q-Turb method was 11%, whereas the averaged estimation error by the regression curve between flow rate and nutrient load was 28%.

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Rong, Haina, and Francisco de León. "Load Estimation of Complex Power Networks from Transformer Measurements and Forecasted Loads." Complexity 2020 (January 22, 2020): 1–14. http://dx.doi.org/10.1155/2020/2941809.

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This paper presents a load estimation method applicable to complex power networks (namely, heavily meshed secondary networks) based on available network transformer measurements. The method consists of three steps: network reduction, load forecasting, and state estimation. The network is first mathematically reduced to the terminals of loads and measurement points. A load forecasting approach based on temperature is proposed to solve the network unobservability. The relationship between outdoor temperature and power consumption is studied. A power-temperature curve, a nonlinear function, is obtained to forecast loads as the temperature varies. An “effective temperature” reflecting complex weather conditions (sun irradiation, humidity, rain, etc.) is introduced to properly consider the effect on the power consumption of cooling and heating devices. State estimation is adopted to compute loads using network transformer measurements and forecasted loads. Experiments conducted on a real secondary network in New York City with 1040 buses verify the effectiveness of the proposed method.

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Li, Yanxi, Xingwen Quan, Zhanmang Liao, and Binbin He. "Forest Fuel Loads Estimation from Landsat ETM+ and ALOS PALSAR Data." Remote Sensing 13, no. 6 (March 20, 2021): 1189. http://dx.doi.org/10.3390/rs13061189.

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Fuel load is the key factor driving fire ignition, spread and intensity. The current literature reports the light detection and ranging (LiDAR), optical and airborne synthetic aperture radar (SAR) data for fuel load estimation, but the optical and SAR data are generally individually explored. Optical and SAR data are expected to be sensitive to different types of fuel loads because of their different imaging mechanisms. Optical data mainly captures the characteristics of leaf and forest canopy, while the latter is more sensitive to forest vertical structures due to its strong penetrability. This study aims to explore the performance of Landsat Enhanced Thematic Mapper Plus (ETM+) and Advanced Land Observing Satellite (ALOS) Phased Arrayed L-band Synthetic Aperture Radar (PALSAR) data as well as their combination on estimating three different types of fuel load—stem fuel load (SFL), branch fuel load (BFL) and foliage fuel load (FFL). We first analyzed the correlation between the three types of fuel load and optical and SAR data. Then, the partial least squares regression (PLSR) was used to build the fuel load estimation models based on the fuel load measurements from Vindeln, Sweden, and variables derived from optical and SAR data. Based on the leave-one-out cross-validation (LOOCV) method, results show that L-band SAR data performed well on all three types of fuel load (R2 = 0.72, 0.70, 0.72). The optical data performed best for FFL estimation (R2 = 0.66), followed by BFL (R2 = 0.56) and SFL (R2 = 0.37). Further improvements were found for the SFL, BFL and FFL estimation when integrating optical and SAR data (R2 = 0.76, 0.81, 0.82), highlighting the importance of data selection and combination for fuel load estimation.

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Jin, Sen, and Shyh-Chin Chen. "Application of QuickBird imagery in fuel load estimation in the Daxinganling region, China." International Journal of Wildland Fire 21, no. 5 (2012): 583. http://dx.doi.org/10.1071/wf11018.

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A high spatial resolution QuickBird satellite image and a low spatial but high spectral resolution Landsat Thermatic Mapper image were used to linearly regress fuel loads of 70 plots with size 30 × 30 m over the Daxinganling region of north-east China. The results were compared with loads from field surveys and from regression estimations by surveyed stand characteristics. The results show that fuel loads were related to stand characteristics, such as stand mean diameter at breast height and stand height. As the QuickBird image using the shadow fraction method represented the stand characteristics well, fuel loads were well estimated from the QuickBird image. QuickBird estimations outperformed those from the lower spatial resolution Thermatic Mapper image. For many fuel classes, the QuickBird estimations were as good as those regressed from surveyed stand characteristics, and thus similar to the surveyed fine and total dead fuel loads. However, coarse fuel loads were not estimated as well using both satellite images owing to their intrinsic low association with stand characteristics. Despite this limitation in estimating coarse fuels, very-high-resolution images such as QuickBird are still valuable in estimating fine fuels, which are critically important in the practice of fire management.

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Tinkham, Wade T., Chad M. Hoffman, Jesse M. Canfield, Emma Vakili, and Robin M. Reich. "Using the photoload technique with double sampling to improve surface fuel loading estimates." International Journal of Wildland Fire 25, no. 2 (2016): 224. http://dx.doi.org/10.1071/wf15027.

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Accurate surface fuel load estimates based on the planar intercept method require a considerable amount of time and cost. Recently the photoload method has been proposed as an alternative for sampling of fine woody surface fuels. To evaluate the use of photoload fuel sampling, six simulated fuel beds of 100 photoload visual estimates and destructively sampled fuel loads were generated at three levels of fuel loading (0.016, 0.060, and 0.120 kg m–2) and two levels of variability (coefficients of variation of ~42 and 85%). We assessed the accuracy and precision of simple random sampling with and without double sampling on surface fuel load estimation. Direct visual estimates often overestimated fuel loads where actual fuel loading was low and underestimated fuel loads where fuel loads were large. We found that double sampling with a classical regression estimation approach provided the most accurate and precise fuel load estimates, substantially improving the accuracy and precision achieved over standard photoload estimation when ń ≥ 20 and double sampling rate ≥20%. These results indicate that fine woody fuel loading estimation with the photoload technique can be improved by incorporating a double sampling approach.

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10

Peters, K. A., and K. A. Busch. "Strain estimation for external event loads." Nuclear Engineering and Design 96, no. 2-3 (October 1986): 437–40. http://dx.doi.org/10.1016/0029-5493(86)90281-5.

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11

Sun, De Fa. "Estimation of Dynamic Wind Pressure for Multi-Span Greenhouse Structural Design." Advanced Materials Research 446-449 (January 2012): 878–82. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.878.

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Based on the contrast analysis of loads provided in foreign and China standards, analysis and discussion are mentioned about the definition and estimation of dynamic wind pressures for multi-span greenhouse structural design in details. Meanwhile, taking advantage of past experience in greenhouse structural design a practical method which can be used in greenhouse design was given for wind loads. Under the present conditions, it is relative safety in calculation wind loads according to Load code for the design of building structures (GB 50009-2001), yet it is unnecessary to make modification of statistical reappearing factor in calculation wind load-dynamic pressure when considering the coefficients of wind pressure depending on height and the gust factor according to Greenhouse structure design load (GB/T 18622-2002).

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12

Arabkhedri, M., F. S. Lai, I. Noor-Akma, and M. K. Mohamad-Roslan. "An application of adaptive cluster sampling for estimating total suspended sediment load." Hydrology Research 41, no. 1 (December 1, 2009): 63–73. http://dx.doi.org/10.2166/nh.2010.113.

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Suspended sediment transport in river for a particular period is a timescale finite population. This population shows natural aggregation tendencies in sediment concentration particularly during floods. Adaptive cluster sampling (ACS) can be potentially conducted for sampling from this rare clustered population and estimating total load. To illustrate the performance of ACS in sediment estimation, a comparative study was carried out in the Gorgan-Rood River, Iran, with around a 5 year daily concentration record. The total sediment loads estimated by ACS were statistically compared to the observed load, estimations of selection at list time (SALT) and conventional sediment rating curve with and without correction factors. The results suggest that none of the sediment rating curves produced accurate estimates, while both ACS and SALT showed satisfactory results at a semi-weekly sampling frequency. The best estimation obtained by the rating curves did not show a percent error better than −40%; however, ACS and SALT underestimated the load at less than 5%. The results of this study suggest ACS could improve river monitoring programs.

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13

Pandey, M. D., and H. J. Sutherland. "Probabilistic Analysis of LIST Data for the Estimation of Extreme Design Loads for Wind Turbine Components*†." Journal of Solar Energy Engineering 125, no. 4 (November 1, 2003): 531–40. http://dx.doi.org/10.1115/1.1626128.

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The robust estimation of wind turbine design loads for service lifetimes of 30 to 50 years that are based on limited field measurements is a challenging problem. Estimating the long-term load distribution involves the integration of conditional distributions of extreme loads over the mean wind speed and turbulence intensity distributions. However, the accuracy of the statistical extrapolation can be sensitive to both model and sampling errors. Using measured inflow and structural data from the Long Term Inflow and Structural Test (LIST) program, this paper presents a comparative assessment of extreme loads using three distributions: namely, the Gumbel, Weibull and Generalized Extreme Value distributions. The paper uses L-moments, in place of traditional product moments, with the purpose of reducing the sampling error. The paper discusses the effects of modeling and sampling errors and highlights the practical limitations of extreme value theory.

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Prpić-Oršić, Jasna, Marko Valčić, and Zoran Čarija. "A Hybrid Wind Load Estimation Method for Container Ship Based on Computational Fluid Dynamics and Neural Networks." Journal of Marine Science and Engineering 8, no. 7 (July 20, 2020): 539. http://dx.doi.org/10.3390/jmse8070539.

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The estimation of wind loads on ships and other marine objects represents a continuous challenge because of its implication for various aspects of exposed structure exploitation. An extended method for estimating the wind loads on container ships is presented. The method uses the Generalized Regression Neural Network (GRNN), which is trained with Elliptic Fourier Descriptors (EFD) of sets of frontal and lateral closed contours as inputs. Wind load coefficients (Cx, Cy, CN), used as outputs for network training, are derived from 3D steady RANS CFD analysis. This approach is very suitable for assessing wind loads on container ships wherever there is a wind load database for a various container configuration. In this way, the cheaper and faster calculation can bridge the gap for the container configurations for which calculations or experiments have not already been made. The results obtained by trained GRNN are in line with available experimental measurements of the wind loads on various container configuration on the deck of a 9000+ TEU container ship obtained through a series of wind tunnel tests, as well as with performed CFD simulation for the same conditions.

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15

Ellis, B. R., and J. D. Littler. "Response of cantilever grandstands to crowd loads. Part 2: load estimation." Proceedings of the Institution of Civil Engineers - Structures and Buildings 157, no. 5 (October 2004): 297–307. http://dx.doi.org/10.1680/stbu.2004.157.5.297.

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Berezin, Leonid, Mykola Rubanka, Alla Rubanka, Yurii Kovalov, and Serhii Pleshko. "Estimation of Fatigue Longevity of Rod Elements of Complex Form." Periodica Polytechnica Mechanical Engineering 65, no. 2 (March 16, 2021): 111–19. http://dx.doi.org/10.3311/ppme.14647.

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The questions of design maintenance of a given fatigue longevity of rods of complex form during the intensification of load modes without changing of geometric, inertial and rigidity parameters of roads are considered. The study is conducted on the example of needles of circular machines with a small diameter of cylinder (automatic half-hose machines). An approach, based on the system of calculation of loads, loadings and resources under the criterion of fatigue strength, is proposed. The key link for the transition from the results of dynamic analysis to the determination of reliability indices is the dependence of limited longevity of needles on the cycles of load to fatigue failure with the use of statistical data on operating time to fatigue failure of the needles in production conditions. Since the random values of loads of the needles do not obey the normal law of distribution, the general description of density of distribution of amplitude of loads is presented. The influence of increase in speed parameters and constructive measures, aimed to reduce the corresponding loads at a current size of critical section of the needles, on the fatigue longevity is analyzed.

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Lee, Sang, Matthew Churchfield, Frederick Driscoll, Senu Sirnivas, Jason Jonkman, Patrick Moriarty, Bjόrn Skaare, Finn Nielsen, and Erik Byklum. "Load Estimation of Offshore Wind Turbines." Energies 11, no. 7 (July 20, 2018): 1895. http://dx.doi.org/10.3390/en11071895.

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The influence of 3 MW Hywind-II wind turbine wakes from an upstream offshore floating wind turbine on a downstream turbine with a separation distance of seven rotor diameters was studied for a site in the Gulf of Maine. The turbines and the platforms were subjected to atmospheric boundary layer flows. Various sensitivity studies on fatigue loads with respect to the positions of the downstream turbine were performed and validated with a large-eddy simulation tool. In particular, the effect of various lateral positions of the downstream turbine relative to the upstream turbine were considered using time-series turbine wake data generated from the large-eddy simulation tool which served as an input to an aero-elastic wind turbine model to assess the loads. The load response from the rotor, tower, and the floating platform for the downstream turbine were sensitive to the lateral offset positions where turbines that were partially exposed to upstream turbine wakes yielded significant increases in the cyclic load range. For the given set of lateral positions for the downstream turbine, the largest damage equivalent load occurred when the turbine was one rotor diameter to the left of the centerline, when looking upstream, which is the position of the turbine fully exposed to upstream turbine wake. On the other hand, the fatigue load on the downstream turbine placed on the right side of the position fully exposed to the upstream turbine wake, yielded lower stress due to the non-symmetric shape of the turbine wake. The configuration associated with the largest damage equivalent loads was further investigated in a large-eddy simulation, modeling both the upstream and downstream turbines. It was found that the energy spectra at the blade rotational frequency were a magnitude order higher for the downstream turbine, especially for surge, heave, pitch, and yaw motion of the platform. The increase of the damage equivalent load for the flapwise blade root moment was 45% compared to the upstream turbine, which can potentially reduce the turbine service life time.

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Guerra, Pedro Raúl De León. "Estimación de Parámetros Para Cargas Contaminantes Conectadas a las Redes de Distribucción." KnE Engineering 3, no. 1 (February 11, 2018): 171. http://dx.doi.org/10.18502/keg.v3i1.1423.

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In this paper we propose a new algorithm for the estimation of the parameters of the harmonic loads connected to the electric distribution system. The new parameter estimation algorithm is based on the weighted least-squares technique. The estimation algorithm solves an optimization problem and minimizes a set of variables which must comply with a series of specifications or characteristics of the harmonic loads. The estimation algorithm is able to obtain a load model with good accuracy comparatively to current -model of the system, due to a good engineering estimation of the initial conditions. Finally the new estimation algorithm could be used for power quality studies and to measure the contribution of the harmonic contamination of the clients connected to the electrical distribution system.Keywords: Harmonics, parameter estimation, weighted least squares, models.

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Poutanen, Tuomo Tapani, Sampsa Pursiainen, Jari Mäkinen, and Tim Länsivaara. "Load combination of permanent and variable loads." Rakenteiden Mekaniikka 51, no. 1 (August 16, 2018): 1–9. http://dx.doi.org/10.23998/rm.65175.

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This paper concentrates on the combination of permanent and variable loads in the structural probability theory and its implementation in codes. In the current codes, the permanent and variable loads are sometimes combined independently, and sometimes they are combined dependently. We propose that, for the safest outcome in the standardized load estimation, the actual permanent and variable loads should be combined dependently without any load reduction. The load reduction arising from the independent combination leads to an unsafe design. For example, when the permanent and variable loads are both equal to 1, the combination load is 2 if the dependent combination is applied. However, the value predicted by the model for independent load combination is only ca 1.8. Although the load formation processes are independent, the dependent combination is applied since the load formation and the load combination are different processes. To support our view, we present arguments and examples based on probability theory, physics and statics and relate them with the current codes.

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Itahashi, S., M. C. Seo, and M. Takeuchi. "Estimation and comparison of nitrogen loads and attenuation in agricultural catchments of Japan and Korea." Water Science and Technology 56, no. 1 (July 1, 2007): 105–13. http://dx.doi.org/10.2166/wst.2007.441.

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To help in clarifying the relationship between the time lag and attenuation of nitrogen (N) loads generated in agricultural catchments, long-term trends in activities that generate N loads and in environmental N loads were estimated in catchments in Japan and Korea dominated by non-point-source emissions. Our approach used statistical data and geographical information system software to analyze pollutant loads. The method was successful in both countries because of the availability of well-developed statistics, geographical information, and weather and water quality monitoring systems, and the accumulation of research data concerning the generation of N loads and the fate of N in soils. Comparison of environmental loads with the loads observed in river water at the outlet of each catchment revealed that: (1) the effect of changes in the environmental load in a catchment appeared almost immediately in the river water quality in Korea, but did not appear clearly even 10 years later in Japan; and (2) the strength of the attenuation appeared to be much lower in Korea than in Japan. These findings suggest that regional characteristics play important roles in the sensitivity of water quality to load-generating activities.

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Carcangiu, S., A. Fanni, P. A. Pegoraro, G. Sias, and S. Sulis. "Forecasting-Aided Monitoring for the Distribution System State Estimation." Complexity 2020 (February 28, 2020): 1–15. http://dx.doi.org/10.1155/2020/4281219.

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In this paper, an innovative approach based on an artificial neural network (ANN) load forecasting model to improve the distribution system state estimation accuracy is proposed. High-quality pseudomeasurements are produced by a neural model fed with both exogenous and historical load information and applied in a realistic measurement scenario. Aggregated active and reactive powers of small or medium enterprises and residential loads are simultaneously predicted by a one-step ahead forecast. The correlation between the forecasted real and reactive power errors is duly kept into account in the definition of the estimator together with the uncertainty of the overall measurement chain. The beneficial effects of the ANN-based pseudomeasurements on the quality of the state estimation are demonstrated by simulations carried out on a small medium-voltage distribution grid.

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Smart, T. S., D. J. Hirst, and D. A. Elston. "Methods for estimation loads transported by rivers." Hydrology and Earth System Sciences 3, no. 2 (June 30, 1999): 295–303. http://dx.doi.org/10.5194/hess-3-295-1999.

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Abstract. Ten methods for estimating the loads of constituents in a river were tested using data from the River Don in North-East Scotland. By treating loads derived from flow and concentration data collected every 2 days as a truth to be predicted, the ten methods were assessed for use when concentration data are collected fortnightly or monthly by sub-sampling from the original data. Estimates of coefficients of variation, bias and mean squared errors of the methods were compared; no method consistently outperformed all others and different methods were appropriate for different constituents. The widely used interpolation methods can be improved upon substantially by modelling the relationship of concentration with flow or seasonality but only if these relationships are strong enough.

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Hwang, Jae-seung, Ahsan Kareem, and Wha-jung Kim. "Estimation of modal loads using structural response." Journal of Sound and Vibration 326, no. 3-5 (October 2009): 522–39. http://dx.doi.org/10.1016/j.jsv.2009.05.003.

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Høiset, Stian, Bjørn H. Hjertager, Tron Solberg, and Kjell A. Malo. "Statistical estimation of loads from gas explosions." Journal of Loss Prevention in the Process Industries 10, no. 4 (July 1997): 271–83. http://dx.doi.org/10.1016/s0950-4230(97)00017-x.

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Baffaut, C., and J. L. Chameau. "Estimation of pollutant loads with fuzzy sets." Civil Engineering Systems 7, no. 1 (March 1990): 51–61. http://dx.doi.org/10.1080/02630259008970570.

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KIM BURTON, A., K. MALCOLM TILLOTSON, and MARK G. BOOCOCK. "Estimation of spinal loads in overhead work." Ergonomics 37, no. 8 (August 1994): 1311–21. http://dx.doi.org/10.1080/00140139408964910.

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Seo, K. W., and C. R. Wilson. "Simulated estimation of hydrological loads from GRACE." Journal of Geodesy 78, no. 7-8 (March 5, 2005): 442–56. http://dx.doi.org/10.1007/s00190-004-0410-5.

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Li, Zhongwei, You-Kuan Zhang, Keith Schilling, and Mary Skopec. "Cokriging estimation of daily suspended sediment loads." Journal of Hydrology 327, no. 3-4 (August 2006): 389–98. http://dx.doi.org/10.1016/j.jhydrol.2005.11.028.

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Maza-Ortega, J. M., A. Gómez-Expósito, J. L. Trigo-García, and M. Burgos-Payán. "Parameter estimation of harmonic polluting industrial loads." International Journal of Electrical Power & Energy Systems 27, no. 9-10 (November 2005): 635–40. http://dx.doi.org/10.1016/j.ijepes.2005.08.004.

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Alonso-Rego, Cecilia, Stéfano Arellano-Pérez, Carlos Cabo, Celestino Ordoñez, Juan Gabriel Álvarez-González, Ramón Alberto Díaz-Varela, and Ana Daría Ruiz-González. "Estimating Fuel Loads and Structural Characteristics of Shrub Communities by Using Terrestrial Laser Scanning." Remote Sensing 12, no. 22 (November 11, 2020): 3704. http://dx.doi.org/10.3390/rs12223704.

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Forest fuel loads and structural characteristics strongly affect fire behavior, regulating the rate of spread, fireline intensity, and flame length. Accurate fuel characterization, including disaggregation of the fuel load by size classes, is therefore essential to obtain reliable predictions from fire behavior simulators and to support decision-making in fuel management and fire hazard prediction. A total of 55 sample plots of four of the main non-tree covered shrub communities in NW Spain were non-destructively sampled to estimate litter depth and shrub cover and height for species. Fuel loads were estimated from species-specific equations. Moreover, a single terrestrial laser scanning (TLS) scan was collected in each sample plot and features related to the vertical and horizontal distribution of the cloud points were calculated. Two alternative approaches for estimating size-disaggregated fuel loads and live/dead fractions from TLS data were compared: (i) a two-steps indirect estimation approach (IE) based on fitting three equations to estimate shrub height and cover and litter depth from TLS data and then use those estimates as inputs of the existing species-specific fuel load equations by size fractions based on these three variables; and (ii) a direct estimation approach (DE), consisting of fitting seven equations, one for each fuel fraction, to relate the fuel load estimates to TLS data. Overall, the direct approach produced more balanced goodness-of-fit statistics for the seven fractions considered jointly, suggesting that it performed better than the indirect approach, with equations explaining more than 80% of the observed variability for all species and fractions, except the litter loads.

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Zhu, Lei, Jin Xi Song, and Chang Qin Zheng. "Pollution Load Estimation of Weihe River Watershed above Linjiacun Section Based on Characteristic Section Load Method." Applied Mechanics and Materials 744-746 (March 2015): 2382–85. http://dx.doi.org/10.4028/www.scientific.net/amm.744-746.2382.

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Weihe River Watershed above Linjiacun Section is taken as the research objective in this paper and NH3-N is chosen as the water quality parameter. According to the discharge characteristics of point source pollutions and non-point source pollutions, a new method to estimate pollution loads-characteristic section load method is suggested and point source pollution and non-point source pollution loads of Weihe River Watershed above Linjiacun Section are calculated in the rainy, normal and dry season in the year 2007. The results show that the monthly point source pollution loads of Weihe River Watershed above Linjiacun Section are discharged stably, the monthly non-point source pollution loads of Weihe River Watershed above Linjiacun Section change greatly, the non-point source pollution load proportions of total pollution load of NH3-N are gradually decreased in the rainy, normal and wet periods.

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Tafesse Tirkaso, Wondmagegn, and Ing-Marie Gren. "Habitat quality and fish populations: impacts of nutrient enrichment on the value of European perch off the east coast of Sweden." Environmental Economics 8, no. 1 (April 8, 2017): 46–56. http://dx.doi.org/10.21511/ee.08(1).2017.05.

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Degradation of marine ecosystems through, e.g., eutrophication and climate change is a concern for sustainable fishery management worldwide, but studies on associated impacts on fish populations are rare. This study examines the effects of eutrophying nutrient loads on the economic value of perch populations along the Swedish east coast by estimating the effects of nutrient loads on the population of perch and, then, simulates the harvest value of future perch population under the changes in nutrient loads. A modified Gordon-Schaefer logistic growth model was used for econometric estimation of perch populations based on annual time series data for the period of 1970-2014. Regression analysis using the fully modified ordinary least square (FMOLS) estimator revealed that phosphorus loads had significant effects on the perch population. A 40% decrease in phosphorus loads, as suggested by the international HELCOM agreement, could increase the steady state perch population by 50%. Simple calculations showed that this could increase the total discounted recreational and commercial harvest value of the perch by 30% over a 30 year period.

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Warburton, Jeff, and Ian Beecroft. "Use of meltwater stream material loads in the estimation of glacial erosion rates." Zeitschrift für Geomorphologie 37, no. 1 (April 23, 1993): 19–28. http://dx.doi.org/10.1127/zfg/37/1993/19.

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Bin, Huang, Yan Mingdong, Liu Xiaogang, and Xiao Mao. "Based on M-Copula Reliability Analysis of Random Load Correlation." Mathematical Problems in Engineering 2020 (August 5, 2020): 1–11. http://dx.doi.org/10.1155/2020/1268762.

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Load is one of the main causes of structural failure, and the correlation among loads would affect the evaluation results of structural performance. The purpose of this paper is to analyze the influence of the correlation among multiple loads on the structural reliability. In this paper, the nonparametric kernel density estimation (NKDE) method is used to estimate the probability density function (PDF) of related loads. In addition, the mixed copula (M-Copula) model is proposed, which combines Gumbel copula, Frank copula, Clayton copula, and weight coefficient, and the model parameters are fitted by MATLAB software to get the correlation of related loads. The reliability based on the related load combination is calculated according to the constructed model. After analyzing three numerical cases, the results show that the probability characteristics of NKDE estimation are very close to the actual conditions, and the reliability calculated by the M-Copula model is larger than those calculated by JCSS, Turkstra, and Gong methods. Using the M-Copula model for load correlation would avoid underestimating the reliability of the structure, which is conducive to structural economic development.

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Ciontea, Catalin Iosif, and Florin Iov. "A Study of Load Imbalance Influence on Power Quality Assessment for Distribution Networks." Electricity 2, no. 1 (March 1, 2021): 77–90. http://dx.doi.org/10.3390/electricity2010005.

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Power quality studies for distribution networks are very important for future network expansions realized by utility companies, so the accuracy of such studies is critical. Load data, including information on load imbalance, could have in many situations a significant influence on the correct estimation of many power quality indicators. This paper investigates the impact of load imbalance on several phase imbalance indicators and voltage quality indicators by comparing the values of these indicators, as calculated in a power quality study using, sequentially, different sets of load data characterized by different load imbalances. The results of this study confirm the original hypothesis, showing that the use of inaccurate consumption profiles for loads leads to an inaccurate estimation of some power quality indicators. In addition, the results highlight the difficulty of approximating the actual consumption profiles of electrical loads so that this approximation does not affect the correctness of the estimation of phase imbalance and voltage quality indicators.

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Pimenov, S. A. "FORMULATION OF A METHOD OF RELIABILITY ASSESSMENT FOR CONSTRUCTIONS ON THE BASIS OF A COMBINATION OF STATISTICAL MODELING AND NUMERICAL METHODS OF STRESS EVALUATION." Vestnik Tomskogo gosudarstvennogo universiteta. Matematika i mekhanika, no. 70 (2021): 51–63. http://dx.doi.org/10.17223/19988621/70/5.

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In this paper, methods for estimating the reliability of constructions are considered. The formulation of a method for estimating the reliability of the design based on a combination of statistical modeling and numerical methods for evaluating stresses is given. The method is based on a "load – bearing capacity" model, which takes into account both stochasticity of mechanical properties of construction materials, randomness of geometric characteristics, and loads of a probabilistic nature. This new method is a system of n nested cycles. The number of governing parameters n depends on the design. The load variation series is calculated in the body of the internal cycle. The load is calculated numerically in terms of stresses using the finite element method. Any commercial solver such as Nastran, Ansys, or Abaqus can be used for this purpose. The probability of failure-free operation (reliability) is calculated involving the variational series of loads and load-carrying ability. For this purpose, the formalized estimation method based on empirical distributions is used. Fundamentals of the latter are available in the monograph "Reliability in Engineering Design" written by Kapur K.C. and Lamberson L.R.. A primary function of the proposed method is to evaluate the probability of failure-free operation of constructions under stationary or quasi-stationary random loads.

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Reymer, Piotr, Wojciech Zieliński, and Artur Kurnyta. "Influence of source data on fatigue estimation of a fighter aircraft." Journal of KONBiN 48, no. 1 (December 1, 2018): 301–22. http://dx.doi.org/10.2478/jok-2018-0057.

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Abstract Aircraft structures during operation are exposed to fluctuating loads caused both by aerodynamic and inertial loads. This fluctuation leads to the creation of fatigue cycles, which gradually diminish the residual durability of the structure. During the design process, the flight envelope is defined as well as the design load spectrum, which then defines the durability of the structure (often expressed in means of flight hours). However, during the operation of an individual aircraft the actual load cycles can be significantly lower or higher than the designed; therefore, load monitoring is essential for safe operation of aircraft structures. The following article shows the results of fatigue analysis based on flight data from different flight data recorders for the Su-22 fighter aircraft.

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Jeon, Sang Youn, and Young Shin Lee. "An Estimation of the Dynamic Buckling Load for the Spacer Grid of Pressurized Water Reactor Fuel Assembly." Key Engineering Materials 326-328 (December 2006): 1603–6. http://dx.doi.org/10.4028/www.scientific.net/kem.326-328.1603.

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This study contains an estimation of the dynamic buckling load for the spacer grid of fuel assembly in pressurized water reactor. Three different estimation methods were proposed for the calculation of the dynamic buckling loads of spacer grid. The dynamic impact tests and analyses were performed to evaluate the impact characteristics of the spacer grids and to predict the dynamic buckling load of the full size spacer grid. The estimation results were compared with the test results for the verification of the estimation methods.

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Chen, Songnian, and Shakeeb Khan. "SEMIPARAMETRIC ESTIMATION OF NONSTATIONARY CENSORED PANEL DATA MODELS WITH TIME VARYING FACTOR LOADS." Econometric Theory 24, no. 5 (May 14, 2008): 1149–73. http://dx.doi.org/10.1017/s0266466608080468.

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We propose an estimation procedure for a semiparametric panel data censored regression model in which the error terms may be subject to general forms of nonstationarity. Specifically, we allow for heteroskedasticity over time and a time varying factor load on the individual specific effect. Empirically, estimation of this model would be of interest to explore how returns to unobserved skills change over time—see, e.g., Chay (1995, manuscript, Princeton University) and Chay and Honoré (1998, Journal of Human Resources 33, 4–38). We adopt a two-stage procedure based on nonparametric median regression, and the proposed estimator is shown to be $\sqrt{n}$ -consistent and asymptotically normal. The estimation procedure is also useful in the group effect setting, where estimation of the factor load would be empirically relevant in the study of the intergenerational correlation in income, explored in Solon (1992, American Economic Review 82, 393–408; 1999, Handbook of Labor Economics, vol. 3, 1761–1800) and Zimmerman (1992, American Economic Review 82, 409–429).

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Agliullin, Timur, Robert Gubaidullin, Airat Sakhabutdinov, Oleg Morozov, Artem Kuznetsov, and Valentin Ivanov. "Addressed Fiber Bragg Structures in Load-Sensing Wheel Hub Bearings." Sensors 20, no. 21 (October 30, 2020): 6191. http://dx.doi.org/10.3390/s20216191.

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The work presents an approach to instrument the load-sensing bearings for automotive applications for estimation of the loads acting on the wheels. The system comprises fiber-optic sensors based on addressed fiber Bragg structures (AFBS) with two symmetrical phase shifts. A mathematical model for load–deformation relation is presented, and the AFBS interrogation principle is described. The simulation includes (i) modeling of vehicle dynamics in a split-mu braking test, during which the longitudinal wheel loads are obtained, (ii) the subsequent estimation of bearing outer ring deformation using a beam model with simply supported boundary conditions, (iii) the conversion of strain into central frequency shift of AFBS, and (iv) modeling of the beating signal at the photodetector. The simulation results show that the estimation error of the longitudinal wheel force from the strain data acquired from a single measurement point was 5.44% with a root-mean-square error of 113.64 N. A prototype load-sensing bearing was instrumented with a single AFBS sensor and mounted in a front right wheel hub of an experimental vehicle. The experimental setup demonstrated comparable results with the simulation during the braking test. The proposed system with load-sensing bearings is aimed at estimation of the loads acting on the wheels, which serve as input parameters for active safety systems, such as automatic braking, adaptive cruise control, or fully automated driving, in order to enhance their effectiveness and the safety of the vehicle.

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HUANG, C. H., A. D. MARTIN, and P. W. DAVENPORT. "EFFECTS OF IMST ON MAGNITUDE ESTIMATION OF RESISTIVE LOADS AND PRESSURE THRESHOLD LOADS." Medicine & Science in Sports & Exercise 34, no. 5 (May 2002): S295. http://dx.doi.org/10.1097/00005768-200205001-01665.

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Wada, K., and S. Fujii. "Estimation of pollutant loads from urban roadway runoff." Water Science and Technology 61, no. 2 (January 1, 2010): 345–54. http://dx.doi.org/10.2166/wst.2010.814.

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A simulation model consisting of a deposition process and a wash-off process was proposed to evaluate the pollutant loads from urban roadways, and was verified based on field survey data obtained over a 5-year period in the Lake Biwa watershed. The model parameters were determined by minimizing the total sum of squares of differences between the observed data and simulated ones. By applying this model to all roadways in the watershed, the calculated amounts of CODMn, organic carbon, nitrogen and phosphorus in particulate forms were 15.9, 15.7, 0.88 and 0.15 kg/(km2 ·d), respectively, and those in dissolved forms were 14.1, 12.5, 2.62 and 0.03 kg/(km2 ·d), respectively. From the results, the pollutant loads of CODMn, TN and TP obtained for the Lake Biwa watershed (total roadway area of 98.9 km2) were estimated to be 2,950, 350 and 18 kg/d, respectively.

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Rosowsky, David V. "Estimation of design loads for reduced reference periods." Structural Safety 17, no. 1 (March 1995): 17–32. http://dx.doi.org/10.1016/0167-4730(94)00037-q.

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Kim, Byeong-Gil, Seung-Hyun Choi, and Seong-Won Lee. "A Battery SOC Estimation Method for Dynamic Loads." IEIE Transactions on Smart Processing & Computing 7, no. 3 (June 30, 2018): 251–56. http://dx.doi.org/10.5573/ieiespc.2018.7.3.251.

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Gallegos-Acevedo, P. M., R. Pérez-Garibay, and A. Uribe-Salas. "Maximum bubble loads: Experimental measurement vs. analytical estimation." Minerals Engineering 19, no. 1 (January 2006): 12–18. http://dx.doi.org/10.1016/j.mineng.2005.04.002.

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Leskovar, Matjaž, and Mitja Uršič. "Estimation of ex-vessel steam explosion pressure loads." Nuclear Engineering and Design 239, no. 11 (November 2009): 2444–58. http://dx.doi.org/10.1016/j.nucengdes.2009.07.023.

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Bielecki, Siawomir. "Estimation of maximum loads of residential electricity users." E3S Web of Conferences 137 (2019): 01006. http://dx.doi.org/10.1051/e3sconf/201913701006.

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The subject matter of coefficient factors is not a frequent object of analysis in the scientific literature. However, because of the use of this term in engineering tasks and because of the constantly changing manner of energy use (resulting from the dissemination of new appliances), there is a need for current analysis and possible revision of the approach based on coefficient factors. The aim of the paper is to compare currently recommended values of this coefficient in the task of estimating the peak output of installations on the example of standards applied in Poland. On the basis of smart metering data and statistical methods, coefficient factors for residential consumers supplied from the municipal distribution network were determined. The results were compared with the currently applied values in accordance with the industry standard issued by the Association of Polish Electrical Engineers (standard N SEP-E-002).

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Dey, Animesh, and Sankaran Mahadevan. "Reliability Estimation with Time-Variant Loads and Resistances." Journal of Structural Engineering 126, no. 5 (May 2000): 612–20. http://dx.doi.org/10.1061/(asce)0733-9445(2000)126:5(612).

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Zaretskii, Yu K., and V. N. Vorob'ev. "Estimation of limiting loads on sandy foundation beds." Soil Mechanics and Foundation Engineering 33, no. 4 (July 1996): 121–26. http://dx.doi.org/10.1007/bf02354253.

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Halle, M., F. Thielecke, and O. Lindenau. "Comparison of real-time flight loads estimation methods." CEAS Aeronautical Journal 5, no. 4 (July 24, 2014): 501–13. http://dx.doi.org/10.1007/s13272-014-0122-3.

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Journal articles on the topic 'Loads estimation'

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