introduction: the key characteristics of positron emission tomography (pet) are its quantitative capability and its sensitivity, which allow the in vivo imaging of biochemical interactions with small amounts of tracer concentrations. therefore, accurate quantification is important. however, it can be sensitive to several physical factors. the aim of this investigation is the assessment of the e...

soil water content is one of the most important parameters for estimating irrigation frequency and providing the plant’s water requirement. since measurement of soil water content is both expensive and time consuming, water movement models are used to estimate these values. in this study, leachw model was used to estimate soil water content for two “dry” (20-29 aug) and “wet” (1-6 jul) periods ...

measuring sensitivity of hydraulic structures is considered as an approach for evaluation of water projects performance, due to lower distribution efficiency in irrigation and drainage project schemes. sensitivity analysis approach for irrigation structures is one of flow analysis methods which are developed in recent years in order to measure the behavior of flow in hydraulic structures in an ...

in this paper, a discrete event simulation model of iranian railway system is used for analyzing performance of the system in freight sector. the model analysis shows more sensitivity of the system on loading and unloading facilities than on number of wagons and locomotives. system optimization through simulation optimization technique, shows that more than 4% of all wagons available in the net...

the need for more comparisons among models is widely recognized. this study aimed to compare three different modelling approaches for their capability to simulate and predict trends and patterns of winter wheat yield in western germany. the three modelling approaches included an empirical model, a process-based model (lintul2), and a metamodel derived from the process-based model. the models ou...