Reachable Accuracy Research Articles

Grounding End-to-End Pre-trained architectures for Semantic Role Labeling in multiple languages

Situated natural language interactions between humans and robots are strictly necessary for complex applications: communication here implies the reference to the environment shared between a user and the robot. This paper proposes a transformer-based architecture that supports the integration of spatial information (as logical representation) about a semantic map of the environment and the input utterances. The generated interpretation is a logical form of the command that makes references to the state of the world through a single end-to-end process, stimulated at each interaction by an explicit linguistic description of the environment. In this specific work, the end-to-end capability of the targeted transformer is studied in light of its multilingual applications where the robot can be queried in different natural languages. The obtained experimental results confirm the applicability of transformers to grounded human-robotic interaction, with benefits in terms of both portability of the approach across domains and effectiveness in terms of reachable accuracy. Moreover, language-specific processing chains are shown to be preferable to large-scale multilingual models for their better trade-off between accuracy and complexity. Overall, the proposed architecture outperforms previous approaches and paves the way for sustainable multilingual architectures.

Marine bubble flow quantification using wide-baseline stereo photogrammetry

Reliable quantification of natural and anthropogenic gas release (e.g.CO2, methane) from the seafloor into the water column, and potentially to the atmosphere, is a challenging task. While ship-based echo sounders such as single beam and multibeam systems allow detection of free gas, bubbles, in the water even from a great distance, exact quantification utilizing the hydroacoustic data requires additional parameters such as rise speed and bubble size distribution. Optical methods are complementary in the sense that they can provide high temporal and spatial resolution of single bubbles or bubble streams from close distance. In this contribution we introduce a complete instrument and evaluation method for optical bubble stream characterization targeted at flows of up to 100 ml/min and bubbles with a few millimeters radius. The dedicated instrument employs a high-speed deep sea capable stereo camera system that can record terabytes of bubble imagery when deployed at a seep site for later automated analysis. Bubble characteristics can be obtained for short sequences, then relocating the instrument to other locations, or in autonomous mode of definable intervals up to several days, in order to capture bubble flow variations due to e.g. tide dependent pressure changes or reservoir depletion. Beside reporting the steps to make bubble characterization robust and autonomous, we carefully evaluate the reachable accuracy to be in the range of 1–2% of the bubble radius and propose a novel auto-calibration procedure that, due to the lack of point correspondences, uses only the silhouettes of bubbles. The system has been operated successfully in 1000 m water depth at the Cascadia margin offshore Oregon to assess methane fluxes from various seep locations. Besides sample results we also report failure cases and lessons learnt during deployment and method development.

Approbation of high-accuracy navigation technology for the benefit of Russia Ministry of Internal Affairs

With a view of implantation of space technology in activities of Ministry of Internal Affairs (MIA) and commercial organizations it is necessary to work through technology of robototechnical complex control in real application conditions. Aim. Investigation of reachable accuracy of coordinate definition of moving objects using global space navigation technology for the benefit of MIA. There are examined problems of coordinate definition accuracy increasing using global space navigation technology that were investigated in pilot project «MIA-Roscosmos». There are given results of onboard equipment tests that were worked in the regime of differential correction data using. There were used navigation apparatus of a geodesic class and the mobile measuring-diagnostic laboratory. There are defined possible field of application of navigation apparatus in an activities of MIA. There are formulated recommendations to using of global space navigation apparatus for the benefit of MIA.

Limitations for field-enhanced atom interferometry

We discuss the possibility to enhance the sensitivity of optical interferometric devices by increasing its open area using an external field gradient that act differently on the two arms of the interfer-ometers. The use of combined electric and magnetic field cancel non linear terms that dephases the interferometer. This is possible using well defined (typically with n $\sim$ 20 Rydberg) states, a magnetic field of few Tesla and an electric field gradient of $\sim$ 10V/cm 2. However this allows only for interaction times on the order of tens of $\mu$s leading a reachable accuracy of only 1 or 2 order of magnitude higher than standard light-pulse atom interferometers. Furthermore, the control of fields and states and 3D trajectories puts severe limits to the reachable accuracy. This idea is therefore not suitable for precision measurement but might eventually be used for gravity or neutrality in antimatter studies.

Smartphone-Based Photogrammetry for the 3D Modeling of a Geomorphological Structure

The geomatic survey in the speleological field is one of the main activities that allows for the adding of both a scientific and popular value to cave exploration, and it is of fundamental importance for a detailed knowledge of the hypogean cavity. Today, the available instruments, such as laser scanners and metric cameras, allow us to quickly acquire data and obtain accurate three-dimensional models, but they are still expensive, require a careful planning phase of the survey, as well as some operator experience for their management. This work analyzes the performance of a smartphone device for a close-range photogrammetry approach for the extraction of accurate three-dimensional information of an underground cave. The image datasets that were acquired with a high-end smartphone were processed using the Structure from Motion (SfM)-based approach for dense point cloud generation: different image-matching algorithms implemented in a commercial and an open source software and in a smartphone application were tested. In order to assess the reachable accuracy of the proposed procedure, the achieved results were compared with a reference dense point cloud obtained with a professional camera or a terrestrial laser scanner. The approach has shown a good performance in terms of geometrical accuracies, computational time and applicability.

Efficient Static and Dynamic Modelling of Machine Structures with Large Linear Motions

Mechatronic structures deform under static and dynamic loads. These deformations lead to deviations at the tool center point (TCP), affecting the reachable accuracy and/or productivity of the machines. The scope of this work is the comparison of calculations and measurements of different static and dynamic errors on a dynamic test bench. A reduced-order modelling approach is applied for the test bench modelling. It uses a combination of modal condensation and moment-matching methods with Krylov subspaces. The different modelling steps and requirements are presented. The same model is used for all static and dynamic evaluations presented within this paper. Static deformations, leading to roll and pitch deviations at the TCP of the test bench structure, are simulated using the described modelling methodology and validated by inclination measurements. The modal behavior of the system is investigated by calculation and compared to the measurements at a single axes position. The spatial change of the frequency response functions of the modelled system is investigated further, by calculation and measurement of the velocity open-loop FRFs of one axis for different machine configurations. In addition, a transient trajectory simulation is performed and compared to the Heidenhain KGM and encoder measurements. The large variety of comparisons shows the efficient applicability of the modelling environment MORe.

Numerical Investigations on the Influence of Process Parameters on the Forming of Gears in Forward Extrusion

The manufacturing of steel gears by cold forging can be realized by using the so called Samanta process. The present study focuses on the one hand on the FE based analysis of the forming of gears in forward extrusion and on the other hand on the modelling of a Samanta process, using the software Simufact.forming. Thereby the influence of different tool geometries and the tribological conditions on the forming are investigated. The aim is to obtain a basic understanding of the material flow and the filling of the tooth cavity depending on the geometry of the Samanta process. For the investigations the common heat-treatable steel 1.7131 (16MnCr5) was used. As an input parameter for the simulation the true stress-true strain curve of the material has been determined within compression tests. For the analysis of the forming the material flow into the cavities and the shape of the tooth flanks are evaluation criteria. Thus the influence of the different parameters on the distribution of equivalent plastic strain, the forming and the reachable accuracy have been investigated.

Wire Fault Diagnosis in the Frequency Domain by Impedance Spectroscopy

The typical methods for the wire fault location are the time-domain reflectometry (TDR) and frequency-domain reflectometry (FDR). In TDR, attenuation and dispersion of the reflected signal limit the reachable accuracy for wire faults location. Because time of flight is evaluated, the wire faults with small impedance changes are difficult to locate. The FDR method has better accuracy than the TDR method, because power signals are used as incident signals and Fourier transform is applied to locate wire faults. However, it is difficult to identify the types of wire faults. A new technique is proposed to detect and locate the wire fault using impedance spectroscopy (IS). IS is applied to measure the input impedance of the wiring system. The load impedance of the wire fault can be abstracted from the input impedance in order to identify the type of wire faults. The input impedance is a period function of the frequency and the period of this function is linearly proportional to the distance to the fault. The fast Fourier transform of the input impedance can give a single spike to locate the wire fault. This novel method enables the location of hard (open and short circuits) and soft (wire faults with small impedance changes) faults. The input impedance of the wire faults in the defined low-frequency range can be applied to identify the types of wire faults. The capacitance and inductance of the cable system can be applied to detect the wire fault if it is open or short circuit. The measurement deviation of the wire fault location in this paper is maximal 40 cm and is independent of the distance to wire faults.

A Method of Indoor Localization Based on BLE4.0 Protocol of Using Beacons

In this paper we discuss our attempt to solve the problem of HAIP(High Accuracy Indoor Position) by using BLE4.0(Bluetooth Low Energy). According to previous research, Wi-Fi Positioning has mainly faced some big challenges. Accuracy is deteriorated by directional handset antennas, which affect the relative AP signal strength; Practical maximum reachable accuracy is 3-10 meters depending on environment; Wi-Fi activities is a big consumption of battery on Mobile Terminal; Now, The Bluetooth Low Energy technology is getting mature. In this paper, we use Bluetooth low energy on iOS device to solve the problem of high accuracy indoor position. In the data-preprocessing step, we use Kalman filter to process the RSSI. In the transition step of RSSI to Distance, we propose a novelty method to adjust the parameters of Log-Distance model dynamically and adaptively according to diagonal beacons’ measurement. We implement our technique and algorithm on iOS device with iOS7.0 SDK. The result shows that error reduced to 0.5m-1.2m range depending on the distance, achieved smaller power consumption.

METHOD FOR GENERATOR FREQUENCY EVALUATION UNDER UNPREDICTABLE CHANGES IN MEASUREMENT INTERVAL SIZE

The method of frequency estimation of the simultaneously and independentlyoperating generators under unpredictable changes in the measurement interval size is studied. Errors arising under the method application due to the transiency of the oscillator frequencies on the frequency estimation interval are considered. The first error component is related to the deviation of the measurable generator phase due to the inherent generator frequency instability; and the second one is determined by the unpredictable changes in the oscillator frequency on the measurement interval. It is noted that the decrease of each of the components imposes incompatible requirements on the duration of the time length. On the basis of the known relations identifying the potentially reachable value of the root-mean-square frequency deviation from the nominal value, the expressions determining the optimum time length are obtained. As a criterion when choosing the time length, the minimum of two errors sum is considered. The analytical relations determining potentially reachable accuracy of the frequency estimates are presented. The unbiasedness, efficiency, and consistency of the estimates obtained are proved.

A New Algorithm for Wire Fault Location Using Time-Domain Reflectometry

In time domain reflectometry (TDR) attenuation and dispersion of the reflected signal limit the reachable accuracy for wire faults location. Because time of flight is evaluated, the wire faults with small impedance changing are difficult to locate. In this paper, a novel method for the TDR-based wire fault detection is presented by transfer function analysis in the time domain. For the determination of the transfer function, a deconvolution should be carried out. Thereby, an inverse problem is to be solved by an adaptive filter approach. Adaptive filters are able to reduce spurious noise of the deconvolution and lead to an acceptable deconvolution estimate. Therefore, a high signal-to-noise-ratio can be reached. The filter's stopband characteristics are optimized by optimization technique to reduce the noise components of the transfer function in the frequency domain. For that a nonlinear fitting procedure is proposed using the Riad-Parruck optimization criterion. The developed method can locate both hard faults (open and short circuits) and soft faults with small impedance changes, and identify the type of wire faults simultaneously in a controlled laboratory environment (without the impedance changes from mechanical vibration, movement, and moisture). The algorithm using adaptive filters and optimization techniques is proposed in this paper for the traditional TDR method, but it is general for most other reflectometry approaches. The estimated wirings are coaxial cables and twisted pair cables, which are used in electrical and power distribution systems.

An Experimental-Computational Technique for Evaluating Magnetic Field Distributions Around Unknown Sources

This paper proposes a hybrid experimental-numerical technique, based on the boundary element method, able to reconstruct the magnetic field distribution in the free space outside the unknown field sources, without requiring the onerous process of source identification. The approach is validated by comparison with experimental data considering a Helmholtz coil system, where the connections of the coils and the supply currents can be controlled to generate different spatial distributions of the magnetic field. The presence of materials with high magnetic permeability, also involving eddy currents, is considered as well. An analysis on the reachable accuracy and on the related parameters is developed, with the final aim of obtaining a satisfactory compromise between result accuracy and experimental burden. Finally, the field values reconstructed by the proposed experimental-numerical technique are compared with the measured ones, showing a good agreement.

Estimation of Relative Direction Angle of Distant, Approaching Airplane in Sense-and-Avoid

Visual detection based sense and avoid problem is more and more important nowadays as UAVs are getting closer to entering remotely piloted or autonomously into the airspace. It is critical to gain as much information as possible from the silhouettes of the distant aircrafts. In our paper, we investigate the reachable accuracy of the orientation information of remote planes under different geometrical conditions, by identifying their wing lines from their detected wingtips. Under the assumption that the remote airplane is on a straight course, the error of the spatial discretization (pixelization), and the automatic detection error is calculated.

Reachable Accuracy and Precision for Tritium Measurements by Calorimetry at TLK

At Tritium Laboratory Karlsruhe (TLK) calorimetry is used as the primary method for tritium accountability and for samples ranging from micrograms to tens of grams. An accuracy of 0.3% is achievable for samples containing more than 0.5 mg tritium and the precision of each calorimeter is better than 0.5%. The results of the TLK calorimeters vary within maximum 0.6% from each other.

Reachable Accuracy and Precision for Tritium Measurements by Calorimetry at TLK

Reachable Accuracy and Precision for Tritium Measurements by Calorimetry at TLK

Evaluation of sampling methods for the estimation of structural indices in forest stands

The paper is about the accurate (i.e. unbiased and precise) and efficient estimation of structural indices in forest stands. We present SIAFOR, a computer programme for the calculation of four nearest-neighbour indices, which describe the spatial arrangement of tree positions, the distribution pattern of species, and the size differentiation between trees. The study uses SIAFOR as a sampling simulator in eight completely stem-mapped forest stands of varying area and structural complexity. We statistically evaluate two sample types (distance and plot sampling), comparing sampling error, bias and minimum sample size for index estimation. We introduce the concepts of measurement expansion factor (MEF) and design expansion factor (DEF) for the technical evaluation of sample type efficiency (optimal sample type). Results indicate that sampling error can reach high levels and that minimum sample sizes for index estimation often amply exceed the limit of 20% of tree density or 20 trees per species per hectare, that we set as the highest feasible sample size in normal situations. We found clear feasibility limits (in terms of minimal tree densities and reachable accuracy levels) for the estimation of all investigated indices. Generally, equal or higher sample sizes are needed for plot sampling than for distance sampling to reach equal accuracy levels. Nevertheless, plot sampling resulted more efficient for the estimation of tree size differentiation at low to medium accuracy levels. For all other investigated indices distance sampling resulted more efficient than plot sampling. Minimum sample size increases with accuracy and is negatively correlated with tree density. At a given accuracy level minimum sample size is highest for the estimation of relative mingling and lowest for tree size differentiation; furthermore it is generally lower in large stands than in small ones. Because of the consistency of our conclusions in all of the investigated stands, we think they apply in most stands of similar area (between 1 and 10 ha) and species diversity (not more than four species).

Kinematische Ketten: Schnelle und exakte Differentiation

The kinematic of robots and their static behaviour can be described by products of homogeneous transformation matrices. For many applications in robotics the Jacobians of these products are needed. Therefore the product has to be differentiated regarding its parameters which are the characteristic values of the robot kinematics (e.g. arm length). Up to now the calculation of the Jacobians has been effected manually by establishing and differentiating the kinematic equations or by using the differential transformation, assuming small changes of the parameters. These methods either require great expenditure and transferability into a general algorithm is very difficult or have weak points regarding the reachable accuracy due to the linearisation. In this article a method is presented, that allows to calculate all partial differentials as well as the different-Jacobians. This method is characterized by the possibility of writing down the partial differentials in a closed form, so they can be calculated exactly and quickly. Apart from the position the orientation and therefore the complete poses and their differentials are discussed. Furthermore the method offers the possibility to calculate the partial differentials of higher order. The user consequently has the feasibility to examine enlarged (non-linear) error-propagations, to use better numerical procedures to identify robot parameters or to improve methods for solving the inverse kinematic problem