modelling efficiency
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2021 ◽  
Vol 20 ◽  
pp. 41-53
Author(s):  
Grzegorz Lenda ◽  
Dominika Spytkowska

The shape of the surface of shell structures, measured by laser scanning, can be modelled using approximating spline functions. Since the 1990s, several modelling techniques have been developed: based on points, meshes, areas outlined on meshes, regions grouping areas with a similar structure. The most effective of them have been used in modern software, but their implementations differ significantly. The most important differences concern the accuracy of modelling, especially places with rapid shape changes, including edges. The differences also affect the mathematical complexity of the created model (the number of unknowns) and the time of its development. These factors contribute to the effectiveness of modelling. Some methods work fully automatically, others allow manual selection of certain parameters, there are also methods that require full manual control. Their selection and application is greatly affected by the user’s intuition and knowledge in the field of creating such surfaces. This study tested the influence of the above factors on the modelling efficiency. A total of six methods of creating spline surfaces were analysed in three software packages of different classes: Geomagic Design X, Solidworks and RhinoResurf. The analyses were carried out on a shell structure of complex shape, consisting of seven patches separated by edges. The created models were assessed in terms of their accuracy of fitting into the point cloud. Additionally, the complexity of the model expressed in the number of control points and the time of its development were determined. The results confirmed the validity of the four methods in terms of model fitting accuracy. The best results were achieved using the semi-automatic method in the most advanced software package and the manual method in the simplest package. This has confirmed the great importance of user experience in terms of theoretical properties of spline functions. However, complexity and development time did not show a direct relationship with the accuracy of the models created. ANALIZA EFEKTYWNOŚCI METOD TWORZENIA POWIERZCHNI SKLEJANYCH DLA MODELOWANIA OBIEKTÓW POWŁOKOWYCH Modelowanie kształtu powierzchni obiektów powłokowych, pomierzonych za pomocą skaningu laserowego, można przeprowadzić za pomocą aproksymacyjnych funkcji sklejanych. Funkcje te dobrze przybliżają kształty o ciągłej krzywiźnie, jakimi są powłoki, jednocześnie wykazując spadki dokładności w miejscach zerwania tej ciągłości. Od lat 90. XX wieku rozwinęło się kilka technik modelowania za ich pomocą, m.in.: wykorzystujących same punkty, siatki mesh, obszary obrysowane na siatkach mesh, regiony grupujące obszary o podobnej strukturze. Najbardziej skuteczne z nich zostały zastosowane we współczesnym oprogramowaniu, ale ich implementacje znacząco się pomiędzy sobą różnią. Najważniejsze różnice dotyczą dokładności modelowania, szczególnie miejsc o szybkich zmianach kształtu, włączając w nie krawędzie. Różnice dotyczą też złożoności matematycznej utworzonego modelu (liczby niewiadomych) oraz czasu jego opracowania. Czynniki te składają się na efektywność modelowania. Część metod działa w pełni automatycznie, inne pozwalają na ręczny dobór pewnych parametrów, są też metody wymagające pełnego sterowania ręcznego. W ich wyborze i stosowaniu duże znaczenie ma intuicja i wiedza użytkownika w zakresie tworzenia tego typu powierzchni. W opracowaniu przetestowano wpływ powyższych czynników na efektywność modelowania. Badaniom poddano łącznie sześć metod tworzenia powierzchni sklejanych w trzech pakietach oprogramowania różnej klasy: Geomagic Design X, Solidworks i RhinoResurf. Analizy przeprowadzono na obiekcie powłokowym o złożonym kształcie, składającym się z siedmiu płatów rozdzielonych krawędziami. Został on pomierzony metodą skaningu laserowego, a scalona chmura punktów stanowiła podstawę do modelowania za pomocą funkcji sklejanych. Utworzone modele oceniono pod względem dokładności wpasowania w chmurę punktów za pomocą wykresów odchyłek punktów od powierzchni, odchyłek średnich oraz maksymalnych. Dodatkowo określono złożoność modelu wyrażoną liczbą punktów kontrolnych oraz czas jego opracowania. Wyniki pozwoliły na potwierdzenie skuteczności czterech metod w zakresie dokładności wpasowania modeli. Najlepsze efekty osiągnięto stosując metodę półautomatyczną w najbardziej zaawansowanym pakiecie oprogramowania oraz metodę ręczną w najprostszym z pakietów. Potwierdza to duże znaczenie doświadczenia użytkownika w zakresie teoretycznych własności funkcji sklejanych. Złożoność i czas opracowania nie wykazywały natomiast bezpośredniego związku z dokładnością tworzonych modeli.


Pomorstvo ◽  
2021 ◽  
Vol 35 (2) ◽  
pp. 341-352
Author(s):  
Jagan Jeevan ◽  
Loke Keng Bin ◽  
Mohamad Rosni Othman ◽  
Nurul Haqimin Mohd Salleh ◽  
Raja Somu ◽  
...  

Trade plays an important role in economic growth. Thence, a smooth cross-border transaction between Thailand-Malaysia-Singapore provides a significant implication in international trade. Currently, cross-border transactions face several issues during the crossing of borders between countries and, specifically, happens during the transactions of cargo. A very rigid documentation process within the custom clearance and theresulting severe congestion will affect the trade flow in this particular zone. Inconsistency of freight transaction documents at the cross-border also makes the transaction procedure more complicated and affects the performance of the manufacturer’s competitiveness. Thus, this paper explores the current issues at the borders involving Thailand-Malaysia-Singapore. This paper also initiates to figure out the challenges and some key success factors in modelling efficiency for cross-border transactions amongst these countries. A qualitative approach has been adapted to answer the proposed research questions. The initial results stressed that congestion, thorough and repetitious documentation procedures, involvement of many documents, as well as the time-consuming clearance of documents are key issues encountered during cross-border freight movement. This situation has caused several issues such as delays in freight delivery, losses in tax collection due to delays, reluctance to share information, and effects on the competitiveness of the freight supply chain. Development in infrastructure, information sharing, regulations, logistics performance, and customs clearance procedure can overcome the problems during cross-border Thailand-Malaysia-Singapore activities. The model outcome is expected to be smoother for the administrative process during customs clearance and it is expected to be able to efficiently reduce costs.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Liqin Zhang ◽  
Xiaojing Tian

Abstract In order to improve the modelling efficiency in dynamic system prediction, this paper proposes a predictive model based on high-order normal differential equations to model high-order differential data to obtain an explicit model. The high-order constant differential equation model is reduced, and the numerical method is used to solve the predictive value. The results show that the method realises the synchronisation of model establishment and parameter optimisation, and greatly enhances the modelling efficiency.


2021 ◽  
Author(s):  
MEHRAJ U DIN DAR ◽  
J.P. Singh

Abstract In the present study, DRAINMOD-NII model was calibrated for the years 2018-2019 and validated for the period 2019-2020 over the two cropping years. The model simulations were statistically evaluated by comparing the measured drain flows and nitrate-nitrogen (NO3-N) with the model simulated drain outflows and nitrate loss. The study results depicted closer agreement between the simulated and observed results for both the calibration and validation periods. The Root Mean Square Error (RMSE) of the drainage rate was 8.88 cm more than observed data,15.41, 0.53 and 0.57 cm were the values recorded for PBIAS, modelling efficiency (NSE) and R2. The similar parameter values for nitrogen load were recorded to be 0.14, 2.76 ,0.84 and 0.88 respectively during the calibration period for rice wheat system. The model was statistically tested during the validation period also, confirming DRAINMOD-NII has the capability to simulate nitrogen losses from the area subjected to subsurface drainage system.


AoB Plants ◽  
2021 ◽  
Vol 13 (5) ◽  
Author(s):  
Weiliang Wen ◽  
Yongjian Wang ◽  
Sheng Wu ◽  
Kai Liu ◽  
Shenghao Gu ◽  
...  

Abstract Geometric plant modelling is crucial in in silico plants. Existing geometric modelling methods have focused on the topological structure and basic organ profiles, simplifying the morphological features. However, the models cannot effectively differentiate cultivars, limiting FSPM application in crop breeding and management. This study proposes a 3D phytomer-based geometric modelling method with maize (Zea Mays) as the representative plant. Specifically, conversion methods between skeleton and mesh models of 3D phytomer are specified. This study describes the geometric modelling of maize shoots and populations by assembling 3D phytomers. Results show that the method can quickly and efficiently construct 3D models of maize plants and populations, with the ability to show morphological, structural and functional differences among four representative cultivars. The method takes into account both the geometric modelling efficiency and 3D detail features to achieve automatic operation of geometric modelling through the standardized description of 3D phytomers. Therefore, this study provides a theoretical and technical basis for the research and application of in silico plants.


Author(s):  
Sonia Valeria Avilés-Sacoto ◽  
Estefanía Caridad Avilés-Sacoto ◽  
Wade D. Cook ◽  
David Güemes-Castorena

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 677
Author(s):  
Michail L. Giannitsopoulos ◽  
Paul J. Burgess ◽  
Goetz M. Richter ◽  
Matt J. Bell ◽  
Cairistiona F. E. Topp ◽  
...  

This study examines the effectiveness of a model called LINGRA-N-Plus to simulate the interaction of climate, soil and management on the green leaf and total dry matter yields of ryegrass in England and Wales. The LINGRA-N-Plus model includes modifications of the LINGRA-N model such as temperature- and moisture-dependent soil nitrogen mineralization and differential partitioning to leaves and stems with thermal time from the last harvest. The resulting model was calibrated against the green leaf and total grass yields from a harvest interval x nitrogen application experiment described by Wilman et al. (1976). When the LINGRA-N-Plus model was validated against total grass yields from nitrogen experiments at ten sites described by Morrison et al. (1980), its modelling efficiency improved greatly compared to the original LINGRA-N. High predicted yields, at zero nitrogen application, were related to soils with a high initial nitrogen content. The lowest predicted yields occurred at sites with low rainfall and shallow rooting depth; mitigating the effect of drought at such sites increased yields by up to 4 t ha−1. The results highlight the usefulness of grass models, such as LINGRA-N-Plus, to explore the combined effects of climate, soil, and management, like nitrogen application, and harvest intervals on grass productivity.


2020 ◽  
Vol 87 (3) ◽  
pp. 341-343
Author(s):  
Roger Iván Espinosa-Mendoza ◽  
Darwin Nicolas Arcos-Álvarez ◽  
Ricardo Alfonso Garcia-Herrera ◽  
Gamaliel Antonio-Molina ◽  
Ricardo Vicente-Pérez ◽  
...  

AbstractIn this research communication we describe the creation of an equation for the prediction of milk yield (MY) from udder volume (UV). A total of 280 measurements were collected between 5 and 15 d postpartum (pp) from 36 multiparous Pelibuey ewes. Study variables were measured between 2 and 9 weeks pp and MY was measured by manual milking, UV prior to and following milking was measured using the technique of making moulds from aluminium foil. The MY ranged from 0.09 to 0.83 kg/d, meanwhile UV prior and following milking ranged from 155 to 1940 and 90 to 1520 cm3, respectively. Measurements of UV had a moderate to high (P < 0.01; 0.58 ≤ r ≤ 0.78) correlation with MY. The UV prior to milking was the best prediction model for MY, which explained 62% of the variation in MY. This equation presented moderate precision (r2 = 0.61) and high accuracy (bias correction factor = 0.94), confirming a good reproducibility index (concordance correlation coefficient = 0.73). Modelling efficiency (MEF = 0.59) showed moderate concordance between observed and predicted values. In conclusion, MY in lactating Pelibuey ewes could be predicted in a moderate way using the predictor variable UV measured with the technique of moulds made with aluminium foil.


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