Small Uncertainties Research Articles

An evaluation of long-term gridded datasets of total columnar ozone retrieved from MERRA-2 and AIRS over the Indian region.

Accurately determining the spatiotemporal variability of ozone on a regional to intercontinental scale is essential for air quality studies. In the present study, a first systematic evaluation and analysis of long-term (2009-2020) gridded datasets (0.5° × 0.625°) of total columnar ozone (TCO) retrieved from Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2TCO) is evaluated for the Indian region. The MERRA-2TCO is first validated with observations (IMDTCO) and then further compared with the Atmospheric Infrared Sounder (AIRSTCO) satellite datasets. For an in-depth comparison and statistical analysis, the dataset has been segregated into seven distinct regions, i.e., Western Himalaya (WH), North East (NE), North Central (NC), North West (NW), West Peninsula India (WPI), East Peninsula India (EPI), and South Peninsula India (SPI). Descriptive statistics (NMSE, FB, R, FA2, and d) reveals a significant correlation of MERRA-2TCO against IMDTCO for Delhi with NMSE (0.0013), FB (- 0.029) and Varanasi NMSE (0.0008), FB (- 0.014). The results of simple linear regression analysis show an increasing TCO trend value of 0.31% and 0.44% per decade in both the cities, respectively. A comparison of MERRA-2TCO with AIRSTCO shows a significant correlation of 0.62-0.87 in different regions of India. Furthermore, in support of Brewer's circulation pattern, an increasing shift of columnar ozone from low (SPI) to high (WH) latitudinal regions is observed. Our results show that the MERRA-2 ozone dataset can be effectively used for ozone air quality studies over India and this analysis may strengthen the need for independent, high-quality, and consistent ozone measurements with small uncertainties.

Further Properties of Tsallis Entropy and Its Application

The entropy of Tsallis is a different measure of uncertainty for the Shannon entropy. The present work aims to study some additional properties of this measure and then initiate its connection with the usual stochastic order. Some other properties of the dynamical version of this measure are also investigated. It is well known that systems having greater lifetimes and small uncertainty are preferred systems and that the reliability of a system usually decreases as its uncertainty increases. Since Tsallis entropy measures uncertainty, the above remark leads us to study the Tsallis entropy of the lifetime of coherent systems and also the lifetime of mixed systems where the components have lifetimes which are independent and further, identically distributed (the iid case). Finally, we give some bounds on the Tsallis entropy of the systems and clarify their applicability.

Highly Sensitive Fiber Relative Humidity Sensor Based on Tip Michelson Interferometer With Agarose Gel Coating

A tip Michelson interferometer (MI) is proposed and experimentally demonstrated for relative humidity (RH) sensing. The device consists of a short capillary tube with a small inner diameter that is spliced to a single-mode fiber (SMF) and coated with agarose gel on its end face, and the solid capillary wall and gel act as the sensing arm of the MI. When the agarose gel absorbs water modules, its refractive index (RI) and volume vary, resulting in the shift of the reflection spectrum of the MI. The relationship between the structural parameters and the performance of the device is revealed after performing theoretical analysis and experimental verification, which provides guidance for optimizing the device. The maximum sensitivity of 0.752 nm/% RH with a linear correlation coefficient of (Adjusted <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}^{{2}}) 0.9927$ </tex-math></inline-formula> within the range of 25%–90% RH is obtained. Moreover, the proposed sensor exhibits good performances of robustness, compact size, high repeatability, fast response (< 100 ms), and small measurement uncertainty (< 0.21% RH), which makes the sensor promising for accurately static or dynamic moisture measuring.

A closed-form solution to time-dependent reliability of aging structures described by gamma-based deterioration models

Structural resistance deterioration is by nature a non-increasing stochastic process with autocorrelation on the temporal scale. The Gamma process is often used to describe the stochastic behavior of resistance deterioration. With Gamma-based deterioration models, the calculation of time-dependent reliability presents a serious challenge, and often Monte Carlo simulation is the only solution to this problem. This paper derives a closed-form solution for time-dependent reliability of aging structures, in which the resistance deterioration is described by a Gamma process and the applied load is modelled as a Gaussian process with a constant standard deviation. The accuracy of the proposed method is verified through a comparison with Monte Carlo simulation results, and its applicability is further illustrated in a time-dependent reliability analysis of an existing highway bridge whose vehicle load is modelled using weigh-in-motion (WIM) data. It is found that the measured vehicle load has a relatively small uncertainty, and the uncertainty associated with resistance deterioration is crucial to the reliability assessment because it dominates the overall uncertainty in the reliability calculation.

Examination of the accuracy of SHRIMP U–Pb geochronology based on samples dated by both SHRIMP and CA-TIMS

Abstract. Estimations of the reproducibility of U–Pb ages from SHRIMP (Sensitive High-Resolution Ion MicroProbe) instruments are based on data from studies that are nearly 2 decades old. Since that time, refinement of analytical procedures and operational improvements have reduced the historically identified uncertainties of SHRIMP U–Pb analysis. This paper investigates 36 SHRIMP thermal ionisation mass spectrometry (TIMS) double-dated “real-world” geologic samples from a variety of igneous rock types to better understand both geological and analytical sources of disagreement between the two dating methods. Geoscience Australia's (GA) use of high-precision chemical abrasion thermal ionisation mass spectrometry (CA-TIMS) for chronostratigraphy in Australian sedimentary basins has produced a substantial selection of precisely dated zircons, which we can use to cross-correlate the SHRIMP and CA-TIMS ages throughout the Phanerozoic. A total of 33 of the 36 ages were reported with external SHRIMP uncertainties less than 1 % (95 % confidence). Six of eight cases where the CA-TIMS age was outside the SHRIMP uncertainty envelope were in samples where the 95 % confidence interval of the reported SHRIMP age was below 0.66 % uncertainty, suggesting that SHRIMP analyses of untreated zircon with smaller uncertainties are probably overoptimistic. The mean age offset between SHRIMP and TIMS ages is 0.095 %, but the distribution appears bimodal. Geological explanations for age discrepancies between SHRIMP and CA-TIMS are suggested by considering intrusive and extrusive age results separately. All but one sample where the SHRIMP age is more than 0.25 % older are volcanic. This offset could be explained by the better single-grain age resolution of TIMS, allowing identification and exclusion of antecrysts from the eruptive population, while SHRIMP does not have a sufficient single-grain precision to deconvolve these populations – leading to an apparent older SHRIMP age. In contrast, SHRIMP ages from plutonic rocks – particularly plutonic rocks from the early Paleozoic – are typically younger than the CA-TIMS ages from the same samples, most likely reflecting Pb loss from non-chemically abraded SHRIMP zircons, while chemical abrasion of zircons prior to TIMS analysis destroyed or corrected these areas of Pb loss.

Constraints on Nuclear Symmetry Energy Parameters

A review is made of constraints on the nuclear symmetry energy parameters arising from nuclear binding energy measurements, theoretical chiral effective field predictions of neutron matter properties, the unitary gas conjecture, and measurements of neutron skin thicknesses and dipole polarizabilities. While most studies have been confined to the parameters SV and L, the important roles played by, and constraints on Ksym, or, equivalently, the neutron matter incompressibility KN, are discussed. Strong correlations among SV,L, and KN are found from both nuclear binding energies and neutron matter theory. However, these correlations somewhat differ in the two cases, and those from neutron matter theory have smaller uncertainties. To 68% confidence, it is found from neutron matter theory that SV=32.0±1.1 MeV, L=51.9±7.9 MeV and KN=152.2±38.1 MeV. Theoretical predictions for neutron skin thickness and dipole polarizability measurements of the neutron-rich nuclei 48Ca, 120Sn, and 208Pb are compared to recent experimental measurements, most notably the CREX and PREX neutron skin experiments from Jefferson Laboratory. By themselves, PREX I+II measurements of 208Pb and CREX measurement of 48Ca suggest L=121±47 MeV and L=−5±40 MeV, respectively, to 68% confidence. However, we show that nuclear interactions optimally satisfying both measurements imply L=53±13 MeV, nearly the range suggested by either nuclear mass measurements or neutron matter theory, and is also consistent with nuclear dipole polarizability measurements. This small parameter range implies R1.4=11.6±1.0 km and Λ1.4=228−90+148, which are consistent with NICER X-ray and LIGO/Virgo gravitational wave observations of neutron stars.

An alternative method for estimating effective elastic thickness by the Vening Meinesz regional isostatic theory with application to continents

SUMMARYEffective elastic thickness, ${T_\mathrm{ e}}$, is a measure of the lithosphere's mechanical strength, and describes the flexural response of the lithosphere to applied loads in the same way as a thin elastic plate. In this study, a new method for estimating ${T_\mathrm{ e}}$ in the spatial domain is presented based on the Veining Meinesz regional isostatic theory. By comparing the absolute values of the correlation coefficients between the observed Moho flexure model and different Veining Meinesz Moho flexure models, the optimal ${T_\mathrm{ e}}$ is determined. Also, the estimated correlation coefficients can be used to examine the effect of the unknown subsurface loads, which are usually difficult to evaluate in the spatial domain. This method is verified to be capable of recovering ${T_\mathrm{ e}}$ variations through synthetic tests for the models with predefined ${T_\mathrm{ e}}$ variations. Finally, the effective elastic thickness is globally determined for the continents using the topography data and recent seismically-derived Moho model. These results are compared with two published ${T_\mathrm{ e}}$ models obtained with different methods. For the areas with relatively small Moho uncertainties and high correlation coefficients, the estimated ${T_\mathrm{ e}}$ variations generally agree with previous results. The differences between three ${T_\mathrm{ e}}$ estimates could characterize the advantages of different methods in specific cases.

An improved device for continuously measuring dimethyl sulfide and isoprene in the air and seawater

The oceanic short-lived trace gases, such as dimethyl sulfide (DMS) and isoprene, play important roles between the surface ocean and the lower atmosphere. Once emitted into the atmosphere, these gases were rapidly oxidized, and their by-products could influence the atmospheric physical and chemical properties by forming particles. However, it is still challenging to collect these trace gases data efficiently due to the lack of a fully automatic measurement method. Therefore, we improved our previous home-made purge and trap system, including the controlling system, purge vessel and heating and cooling device, for measuring DMS and isoprene in the air and seawater respectively. The parameters, such as purge flow, split ratio and heating power rate (for controlling desorption temperature), were investigated by coupling with a gas chromatography–mass spectrometry (GC–MS). Under the conditions of split ratio 8:1, heating power rate 85% and purge flow 50 mL min−1, the peaks and intensities of DMS and isoprene standards were found to be sharp and significant. The standard curves were also established with high linear correlations (R2 > 0.97). The system was reliable and stable with small uncertainty (<5%) and low detection of limit (0.1 ppb and 4 ppt for the DMS and isoprene respectively in air sample, 0.2 nmol L−1 and 6 pmol L−1 for the DMS and isoprene respectively in water sample). Finally, the developed measurement method was successfully used to continuously detect the seawater and air samples. It is anticipated that our method could be widely spread because there are still many labs employing the traditional low automatic purge and trap system.

CNN parameter design based on fault signal analysis and its application in bearing fault diagnosis

As a representative deep learning network, Convolutional Neural Network (CNN) has been extensively used in bearing fault diagnosis and many good results have been reported. In Prognostics and Health Management (PHM) field, the CNN’s input size is usually designed as a 1D vector or 2D square matrix, and the convolution kernel size is also defined as a square shape like 3 × 3 and 5 × 5, which are directly adopted from the image recognition. Though satisfying results can be obtained, CNN with such parameter specifications is not optimal and efficient. To this end, this paper elaborated the physical characteristics of bearing acceleration signals to guide the CNN design. First, the fault period under different fault types and shaft rotation frequency were used to determine the size of CNN’s input. Next, an exponential function was involved in fitting the envelope of decaying acceleration signal during each fault period, and signal length within different decaying ratios was used to define the CNN’s kernel size. Finally, the designed CNN was validated with the Case Western Reserve University bearing dataset and Paderborn University bearing dataset. Results confirm that the physics-guided CNN (PGCNN) with rectangular input shape and rectangular convolution kernel works better than the baseline CNN with higher accuracy and smaller uncertainty. The feasibility of designing CNN parameters with physics-guided rules derived from bearing fault signal analysis has also been verified.

Final report of CCQM-P204, comparison on CO2 isotope ratios in pure CO2

Final report of CCQM-P204, comparison on CO2 isotope ratios in pure CO2

Reducing the Speckle-Induced Measurement Uncertainty in Laser Triangulation Sensors

Laser triangulation sensors are one of the most commonly used optical sensors in dimensional metrology and quality control. This article presents a method for simulating the laser speckle-induced measurement uncertainty, representing a major performance limitation of these sensors, as well as the effects of speckle reduction mechanisms based on spatio-temporal averaging. To investigate the relation between triangulation angle and the resulting speckle-induced uncertainty, simulations are performed for three sensor geometries, revealing that a larger angle results not only in a smaller measurement range but also in a reduced influence of laser speckle and a smaller uncertainty. A parameter study on a speckle-reducing moving diffuser mechanism, integrated into the optical sensor path, investigates the achievable improvement for various combinations of motion frequency and amplitude. The accuracy of the simulation results is validated by measurements conducted with an experimental setup, demonstrating good agreement between the measured and simulated uncertainty values with and without the speckle reduction mechanism. It is shown that the diffuser is capable of reducing the resulting speckle-induced measurement uncertainty by up to 63%.

TRYING UNCERTAINTY

The epigraph to Literary Theories of Uncertainty is taken from Kafka’s The Trial: ‘Selbst die kleinste Unsicherheit in der geringfügigsten Sache ist doch immer quälend’: ‘Even the smallest uncertainty in the slightest of matters is still always agonising’. From Miss Montag’s equivocal consolation to Josef K.: Now I hope also to have acted in your interest, as even the smallest uncertainty in the slightest of matters is still always agonising, and if one can, as in this case, easily eliminate it, then it is better if this is done promptly. We can imagine a principle for criticism that proposes precisely this: if one can easily eliminate an uncertainty, then it is best done promptly. The modern research essay is broadly structured upon the ritualised creation of tension, some lightly agonising uncertainty, followed by the release provided by a systematic resolution. The original Montaignesque essai, dedicated to the trials and travails of experience and exploration, has transformed generically to become more like a trial in our English legal sense. Such a critical principle as we may take from the epigraph would require, as Kafka does, a hefty dose of irony. As Mette Leonard Høeg duly describes in her introduction, literature’s effect so depends upon the power of uncertainty that it is a disservice to bluntly resolve it. Artistic features and figurations, paradoxes, ambiguities of the human condition, these uncertainties as presented in literature cannot be resolved easily or promptly. To perform a rational and systematic analysis of a literary work, to make certain that which is uncertain, risks eliminating the experience of uncertainty. This potential incongruence between criticism and literary experience also pertains to the current post-critique movement in America, which proposes that the hermeneutics of suspicion inherent in a certain kind of criticism reduces a work to an encoded message needing decoding; and to get back to literature we must consider moving beyond critique (read theories: Marxist, queer, eco-, and so on). Institutional mechanisms like the peer-review process or the Research Excellence Framework may play their part in shaping essays that function like trials: essays that may or may not acknowledge a literary work’s competing and simultaneous truths, and in any case by the end pronounce judgement.

High-precision abundances of first-population stars in NGC 2808: confirmation of a metallicity spread

Photometric investigations have revealed that Galactic globular clusters (GCs) exhibit internal metallicity variations amongst the so-called first-population stars, which until now were considered to have a homogeneous initial chemical composition. This is not fully supported by the sparse spectroscopic evidence, which so far gives conflicting results. Here, we present a high-resolution re-analysis of five stars in the Galactic GC NGC 2808 taken from the literature. Target stars are bright red giants with nearly identical atmospheric parameters belonging to the first population according to their identification in the chromosome map of the cluster, and we measured precise differential abundances for Fe, Si, Ca, Ti, and Ni to the ∼0.03 dex level. Thanks to the very small uncertainties associated with the differential atmospheric parameters and abundance measurements, we find that target stars span a range of iron abundance equal to 0.25 ± 0.06 dex. The individual elemental abundances are highly correlated with the positions of the stars along the extended sequence described by first-population objects in the cluster chromosome map: bluer stars have a lower iron content. This agrees with inferences from the photometric analysis. The differential abundances of all other elements also show statistically significant ranges that point to intrinsic abundance spreads. The Si, Ca, Ti, and Ni variations are highly correlated with iron variations and the total abundance spreads for all elements are consistent within the error bars. This suggests a scenario in which short-lived massive stars exploding as supernovae contributed to the self-enrichment of the gas in the natal cloud while star formation was still ongoing.

Stochastic perturbation method for optimal control problem governed by parabolic PDEs with small uncertainties

In this paper, we investigate the first-order and second-order perturbation approximation schemes for an optimal control problem governed by parabolic PDEs with small uncertainties. First, we propose the finite dimensional noise assumption for the random coefficient, and expand the state and co-state variables up to a certain order with respect to a small parameter by using the perturbation technique. Then, we insert all the expansions into the known deterministic parametric optimality system, and obtain the first-order and second-order optimality systems. These two systems are discretized by the finite element method in space and the backward Euler method in time to establish the first-order and second-order approximate schemes. Further, a priori error estimates are derived for the state, co-state and control variables of the first-order and second-order approximation, respectively. Finally, some numerical experiments are presented to verify the theoretical results.

Seasonal variation of transit time distribution and associated hydrological processes in a Moso bamboo watershed under the East Asian monsoon climate

Understanding seasonal variation of the transit time distribution of stream discharge and evapotranspiration is crucial in exploring the flow pathways and the rainfall-storage-streamflow processes in a watershed of interest . Here, both time-variant and time-invariant StorAge Selection (SAS) functions were adopted to estimate the transit time distribution in a Moso bamboo watershed under the East Asian monsoon climate. Daily stable isotopic compositions (δ18O, δ2H) of precipitation and streamflow at the watershed outlet from 1 October 2017 to 31 December 2020 were measured to calibrate the model parameters. The time-variant SAS method considering watershed wetness performs slightly better than the time-invariant SAS method, implying adding a watershed wetness indicator in the time-variant model results in only a minor improvement. Young water fraction and median age as two streamflow age measures were derived from the time-variant SAS model. The median age decreases abruptly within several days at three periods (one is in January 2020, and the other two periods are in Meiyu season) with larger uncertainty, while the estimated young water fraction varies gradually with much smaller uncertainty. The young water fraction derived from the time-variant SAS method appears to be more reliable than that estimated by the tracer cycle damping method. For stream discharge, the storage preferentially releases younger water to discharge under wetter conditions in the East Asian summer monsoon (EASM; June-September) period, while this phenomenon does not occur in the East Asian winter monsoon (EAWM; October-May) period. The larger hourly rainfall intensity for the whole EASM period (mean intensity 2.08 mm/h) likely enhances direct contribution of event water to streamflow than that in the EAWM period (mean intensity 0.75 mm/h). The evapotranspiration is estimated to extract older water than stream discharge in both the EAWM period and the EASM period. That is likely related to the occurrence of ecohydrological separation, and root water uptake below the soil-bedrock interface.

Design Under Uncertainties of the Thermal Ablation Treatment of Skin Cancer

Abstract This computational work deals with the optimal design of the thermal ablation treatment of skin cancer, by considering uncertainties in the model parameters. The tumor and other tissues were heated by a laser. Nanoparticles were used to improve the effects of the heating procedure and to promote thermal damage localized in the region containing the tumor. Treatment protocols examined in this work involved one single heating session with different prespecified durations, where the design variables were considered as the volume fraction of nanoparticles in the epidermis and tumor, as well as the time variation of the incident laser fluence rate. The optimal design problems were solved with the Markov Chain Monte Carlo method, by applying a modified version of the Metropolis-Hastings algorithm with sampling by blocks of parameters. The two parameter blocks were given by the properties of the tissues and by the design variables. The prior for the volume fraction of nanoparticles was given by a truncated Gaussian distribution, while a noninformative Gaussian Markov random field prior was used for the time variation of the laser fluence rate. The posterior distributions of the design variables were estimated by taking into account uncertainties in the model parameters and the desired statistical distribution of the thermal damage in the region of interest. The stochastic simulations resulted in optimal thermal damages with small uncertainties, which closely followed their desired statistical distribution functions.

Runoff simulation and projection in the source area of the Yellow River using the SWAT model and SSPs scenarios

The source area of the Yellow River (SAYR) is one of the world´s largest wetlands containing the greatest diversity of high altitude marshlands. For this reason, its response to climate change is extremely significant. As revealed by different studies, the response of hydrological processes to global warming results in high uncertainties and complexities in the water cycle of the SAYR. Thus, understanding and projecting future runoff changes in this region has become increasingly important. In the present investigation, we used runoff and meteorological data of the SAYR from 1976 to 2014 (historical period). In addition, Digital Elevation Model (DEM), land-use, and soil data for the period 1976 to 2100 were used considering three future SSPs (Shared Socioeconomic Paths) scenarios of 8 models selected from the Coupled Model Intercomparison Project Phase 6 (CMIP6). The Soil and Water Assessment Tool (SWAT) was used to simulate, project, and analyze potential variations and future runoff of the main hydrological stations (Jimai, Maqu, and Tangnaihai) located in the SAYR. The results showed that: 1) The SWAT model displayed good applicability in historical runoff simulation in the SAYR. A small runoff simulation uncertainty was observed as the simulated value was close to the measured value. 2) Under three different 2021–2100 SSPs scenarios, the yearly discharge of the three hydrological stations located in the SAYR showed an increasing trend with respect to the historical period. Future runoff is mainly affected by precipitation. 3) We compared the 1976–2014 average annual runoff with projected values for the periods 2021–2060 and 2061–2100. With respect to 2021–2060, the lowest and highest increases occurred at Tangnaihai and Maqu Stations in the emission scenarios without (SSP585) and with mitigation (SSP126), respectively. However, the highest and lowest increments at Jimai Station were observed in the intermediate emission (SSP245) and SSP126 scenarios, respectively. Moreover, in 2061–2100, the Maqu and Tangnaihai Stations showed the lowest and highest increments in the SSP585 and SSP245 scenarios, correspondingly. In Jimai Station, the lowest increment occurred in SSP126. The yearly average discharge in the near future will be smaller than that in the far future. Overall, this study provides scientific understanding of future hydrological responses to climate changes in the alpine area. This information can also be of help in the selection of actions for macro-control, planning, and management of water resources, and the protection of wetlands in the SAYR.

Phase-stabilized UV light at 267 nm through twofold second harmonic generation.

Providing phase stable laser light is important to extend the interrogation time of optical clocks towards many seconds and thus achieve small statistical uncertainties. We report a laser system providing more than 50 µW phase-stabilized UV light at 267.4 nm for an aluminium ion optical clock. The light is generated by frequency-quadrupling a fibre laser at 1069.6 nm in two cascaded non-linear crystals, both in single-pass configuration. In the first stage, a 10 mm long PPLN waveguide crystal converts 1 W fundamental light to more than 0.2 W at 534.8 nm. In the following 50 mm long DKDP crystal, more than 50 µW of light at 267.4 nm are generated. An upper limit for the passive short-term phase stability has been measured by a beat-node measurement with an existing phase-stabilized quadrupling system employing the same source laser. The resulting fractional frequency instability of less than 5×10-17 after 1 s supports lifetime-limited probing of the 27Al+ clock transition, given a sufficiently stable laser source. A further improved stability of the fourth harmonic light is expected through interferometric path length stabilisation of the pump light by back-reflecting it through the entire setup and correcting for frequency deviations. The in-loop error signal indicates an electronically limited instability of 1 × 10-18 at 1 s.

Assessing the spatial variability of saturated soil hydraulic conductivity at the watershed scale using the sequential Gaussian co-simulation method

Accurate spatial characterization of saturated soil hydraulic conductivity (KSat) is vital for modeling hydrological processes. An effective representation of KSat by field sampling is very difficult on a watershed scale, due the heterogeneity of landscape characteristics for wide land surfaces. To improve the estimation of spatial distributions of KSat at this scale, Sequential Gaussian Simulation (SGS) and Sequential Gaussian Co-Simulation (SGCS) algorithms were applied. The study was conducted in a 70 ha watershed, with 178 sampling points. In addition to KSat the database is composed of Bulk Density (BD), Total Porosity (TP), Macroporosity (Mac), Microporosity (Mic) and Organic Carbon (OC). The Land Use (LU) was also quantified as a regionalized variable. A principal component analysis generated additional two regionalized variables (PC1 and PC2). The simulations were evaluated by faithfully reproducing the stochastic and spatial characteristics of the KSat original data. To estimate the KSat, a univariate SGS was run first. The reproduction of the KSat histograms was satisfactory, while the semivariograms of the simulated fields underestimated the sill. The SGCS was run using five different secondary variables: BD; Mac; LU; PC1 and PC2. All SGCS satisfactorily represented the original KSat histogram, with a slight overestimation for some simulated fields. The semivariogram was very well reproduced for SGCS, being an indication that the process was quite efficient for all secondary variables. The smallest uncertainties were identified for the SGCS that used BD and Mac as secondary variables while the greatest uncertainties were associated with the SGS. The results of this study demonstrate that soil hydrological attributes as BD and Mac are a reliable auxiliary dataset to improve the spatial assessment of KSat by SGCS at watershed scale.

Interval-analysis-based determination of the trajectory-reachable workspace of planar cable-suspended parallel robots

This paper proposes an interval-analysis-based algorithm to determine the trajectory-reachable workspace (TRW) of planar two-degree-of-freedom (DOF) cable-suspended parallel robots and planar three-DOF cable-suspended parallel robots. The TRW is a set of target points that the end-effector can reach along a given trajectory under the cable tension constraint. The method includes two sufficient conditions for a continuous set of target points to lie fully inside or outside the TRW. The two conditions can be verified by the implementation of interval-analysis-based methods. On the basis of these two verifiable sufficient conditions, a TRW determination method using branch-and-prune algorithms is presented. This method avoids the discretization of a continuous trajectory set, which guarantees the accuracy of TRW determination. Moreover, this method can determine the TRW when there are small uncertainties regarding the robot geometric parameters . • A new Trajectory-Reachable Workspace (TRW) determination method based on interval analysis. • High accuracy in determination TRW of planar cable-suspended parallel robots. • Computational time advantage in verification that a prescribed workspace belongs to TRW. • Small uncertainties on the geometric parameters can be handled in the determination of TRW.