Hasil untuk "Geodesy"

W. Banerdt, S. Smrekar, D. Banfield et al.

Q. Kong, D. Trugman, Z. Ross et al.

This article provides an overview of current applications of machine learning (ML) in seismology. ML techniques are becoming increasingly widespread in seismology, with applications ranging from identifying unseen signals and patterns to extracting features that might improve our physical understanding. The survey of the applications in seismology presented here serves as a catalyst for further use of ML. Five research areas in seismology are surveyed in which ML classification, regression, clustering algorithms show promise: earthquake detection and phase picking, earthquake early warning (EEW), ground‐motion prediction, seismic tomography, and earthquake geodesy. We conclude by discussing the need for a hybrid approach combining data‐driven ML with traditional physical modeling.

Xianteng Wang, Xue Li, Zhumei Liu et al.

The fundamental attribute that is essential for the seismic capacity assessment of houses is the building structure type. Conventionally, remote sensing assessment of the seismic capacity for houses has been based on the image features of individual houses, instead of the spatial similarity between them. To enhance the classification accuracy of house structure types, this work proposes a minimum spanning tree (MST) house clustering structure type classification method based on the spatial similarity of houses. First, the method employs the geometric characteristics of residential buildings to calculate the Gestalt factor that characterizes the visual distance. Subsequently, a Delaunay triangular mesh is constructed to create a proximity map between the houses, with the MST generated using visual distance as the weighting factor. Then, the spatial proximity similarity of house clusters is obtained through pruning. Finally, a support vector machine is employed to categorize the architectural structure of the housing complex, viz., simple houses, brick–concrete houses, and frame houses. This classification is based on the geometric, textural, height, and spatial distribution characteristics of the houses. We have conducted a remote sensing classification experiment of house structure types with Zhushan County, Hubei Province as the study area. The results show that the MST clustering method improves the classification accuracy of brick–concrete houses to 95.4% and the classification accuracy of simple houses to 93.4%. Compared to the single-family-based classification method of building structure types, the classification accuracy of frame-structure buildings is improved to 87%. The Kappa coefficient increased to 0.89. This study significantly improves the classification accuracy of building structure types by introducing spatial similarity. Furthermore, it shows the potential for spatial similarity in classifying building structure types.

Zechao Bai, Yuxiao Qin, Yanping Wang et al.

Monitoring the structural deformation of bridge with high precision during the operation process is crucial for assessing its health. This study proposes a practical strategy for jointly measuring multi-scale periodic dynamic deformation in bridges using both spaceborne and ground-based Interferometric Synthetic Aperture Radar (InSAR) technologies. The proposed strategy involves extracting seasonal periodic deformation by applying thermal expansion components with spaceborne Persistent Scatterer InSAR (PS-InSAR) and capturing daily periodic deformation using a two-stage atmospheric phase screen compensation ground-based InSAR method. This study focuses on a double-tower cable-stayed and rigid frame system bridge to investigate the spatiotemporal evolution of bridge multi-scale periodic dynamic deformation patterns. The monitoring results indicate that the geometric state and deformation pattern of the bridge remained stable, exhibiting significant seasonal and daily dynamic deformations that were either positively or negatively correlated with temperature changes. Seasonal periodic deformation captured by spaceborne InSAR showed maximum displacements near expansion joints, while tower deformation remained constrained within ±5 mm. Daily periodic deformation captured by ground-based InSAR revealed significant displacements at the bridge tower top, contrasting with minimal deformation of ±2 mm near fixed bearings. These deformations exhibited significant correlations with temperature changes. Both the deformation trend and magnitude confirmed to the computational results of the bridge structure design.

Peter Vollmair, Anja Schlicht, Urs Hugentobler

The ACES mission of the European Space Agency combines optical and microwave-based geodetic observation techniques with highly accurate atomic clocks to achieve a new level of accuracy for geodesy and fundamental physics applications. In addition, the combination of two high-precision measurement techniques provides an even more exciting insight into their errors. Fundamental physics is particularly interested in experiments that require high precision between the results of the successive passes of a satellite. An example of such an experiment is the determination of gravitational redshift. Geodesy applications, in contrast, require both high accuracy and precision. Especially for applications like precise ranging or time synchronization, all possible error influences must be characterized and determined with high precision. Therefore, electronic delays of microwave link terminals pose a challenge to achieving high accuracy. They must, therefore, be calibrated, and the stability of the electronic delays must be monitored. While optical observation techniques can be calibrated sufficiently on the ground, the calibration of microwave measurements before a launch is not precise enough, and continuous monitoring is also not possible. In this study, four calibration methods were tested, all based on colocating optical and microwave measurements onboard a satellite and on the ground. The results of two methods achieved the required accuracy of 100 ps for time synchronization, with a mean error and standard deviation of better than 4 ps and 55 picoseconds, respectively. Correlations between the measured parameters were identified, and the impact of the different approaches on accuracy was investigated. It will be shown that the satellite-based colocation of two different geodetic observation techniques has clear advantages, and the calibration results achieved the required accuracy for geodetic applications in this simulation study.

J.L. Fuentes-Bargues, A. Sánchez-Lite, C. González-Gaya et al.

Accidents at work are a problem in today's economic structures, but if they result in the loss of human lives, the economic and social cost is even higher. The development of prevention policies, both at governmental and sectoral level, has led to a progressive reduction of occupational accidents, but number of fatal accidents remain high. The aim of this study is to explore the evolution of fatal accidents at work in Spain for the period 2009–2021, analyse the relationship between the main variables, and propose a predictive model of fatal occupational accidents in Spain. Data for this study are collected from occupational accident reports via the Delt@ (Electronic declaration of injured workers) IT system. The study variables were classified into five groups: temporal, personal, business, circumstances, and consequences. Fatal accidents at work are more common in males and in older workers, especially in workers between 40 and 59 years old. Companies with less than five workers have the highest percentage of fatal accidents, and the transport subsector and that the worker is carrying out his/her usual work have a strong correlation in the fatal accidents. Results can help to the agents involved in the health and safety management to develop preventive measures, and action plans.

Lai Xiang, Ying Xu, Jianhui Cui et al.

Along with the IoT technology, the importance of indoor positioning is increasing, but the accuracy of the traditional fingerprint positioning algorithm is negatively affected by the complex indoor environment. This issue of low indoor spatial geolocation localization accuracy when the signal is collected away from the present stage occurs due to the signal instability of the iBeacon in the traditional fingerprint localization algorithm, which generates a variety of factors such as object blocking and reflection, multipath effect, etc., as well as the scarcity of reference fingerprint data points. In response, this study proposes an inverse distance-weighted optimization WKNN algorithm for indoor localization based on the GM(1,1) model. By implementing GM(1,1) model pre-process leveling, the original fingerprint library was reconstructed into a large-capacity fingerprint database using the inverse distance-weighted interpolation method. The local inverse distance-weighted interpolation was used for interpolation, combined with the WKNN algorithm to complete the coordinate solution in real time. This effectively solved the issue of low localization accuracy caused by the large fluctuation of the received signal strength (RSS) sampling measurement data and the existence of few reference fingerprint datapoints in the fingerprint database. The results show that this algorithm reduced the average positioning error by 5.9% compared with ordinary kriging (OK) interpolation leveling and reduced the average positioning error by 18.2% compared with the indoor spatial location accuracy of the original fingerprint database, which can effectively improve the positioning accuracy and provide technical support for indoor location and navigation services.

Xingxing Li, Chengbo Liu, Yongqiang Yuan et al.

As an essential infrastructure that provides positioning, navigation, and timing services, China constructed the BeiDou Navigation Satellite System (BDS). The last BDS satellite was launched in June 2020, which represents the completion of BDS. BDS’s constellation consists of Medium Earth Orbit (MEO), Inclined Geosynchronous Orbit (IGSO), and Geostationary Orbit satellites. The precise modeling of non-conservative forces for BDS satellites is a challenging task. As an independent observation, Satellite Laser Ranging (SLR) is an important validation method of GNSS orbit modeling. In this paper, we validated the precise orbit products of different Analysis Centers (ACs) by using SLR observations, focusing on the BDS orbit modeling. By comparing BDS precise orbit products generated by four ACs with respect to SLR observations for the period of February 2017 to March 2021, we proved that an obvious satellite signature effect exists in the SLR residuals of BDS observed by multi-photon stations. The result indicates that multi-photon stations have a root mean square (RMS) of SLR residuals about 5 mm lower than that of single-photon detectors. The slope of SLR residuals with regard to nadir angle of IGSO satellites for single-photon and multi-photon stations is −2.0 and −2.5 mm/deg, respectively, while the slope of MEO satellites for these stations is about −0.6 to −0.3 and −1.0 to −0.4 mm/deg, respectively. To assess the effect of non-conservative force modeling, we selected seven high-performing stations, including five single-photon and two multi-photon stations. By comparing the SLR residuals of four ACs’ orbits, we analyzed the effect of the solutions of orbit processing, especially solar radiation pressure (SRP) models. We found that some centers may have modeling defects, including BDS-3 orbits of the Deutsches GeoForschungsZentrum and BDS-2 orbits of the European Space Agency, inferred from the large RMS of SLR residuals. Modeling the SRP of BDS satellites is challenging, while an appropriate prior box-wing model can improve the accuracy of SRP modeling and provide a more stable performance.

J. Knechtel, L. Klingbeil, J.-H. Haunert et al.

Terrestrial laser scanning has become more and more popular in recent years. The according planning of the standpoint network is a crucial issue influencing the overhead and the resulting point cloud. Fully static approaches are both cost and time extensive, whereas fully kinematic approaches cannot produce the same data quality. Stop-and-go scanning, which combines the strengths of both strategies, represents a good alternative solution. In the scanning process, the standpoint planning is by now mostly a manual process based on expert knowledge and relying on the surveyor’s experience. This paper provides a method based on Mixed Integer Linear Programming (MILP) ensuring an optimal placement of scanner standpoints considering all scanner-related constraints (e.g. incidence angle), a full coverage of the scenery, a sufficient overlap for the subsequent registration and an optimal route planning solving a Traveling Salesperson Problem (TSP). This enables the fully automatic application of autonomous systems for providing a complete model while performing a stop-and-go laser scanning, e.g. with the <i>Spot</i> robot from <i>Boston Dynamics</i>. Our pre-computed solution, i.e. standpoints and trajectory, has been evaluated surveying a real-world environment using a 360&deg; panoramic laser scanner and successfully compared with a precise LoD2 building model of the underlying scene. The performed ICP-based registration issued from our fully automatic pipeline turns out to be a very good and safe alternative of the otherwise laborious target-based registration.

Junichi Nakajima

Abstract We carried out seismic tomography study to reveal three-dimensional (3D) seismic velocity structures in the Noto peninsula, Japan, where swarm-like seismic activity started in December 2020. The obtained results reveal a highly heterogeneous structure in the crust. The most striking feature is the existence of a low-velocity anomaly in the lower crust beneath the Noto earthquake swarm. Although the data set used in this study cannot resolve the upper mantle structure, previous regional tomographic studies suggest that a low-velocity anomaly exists at depths of 50–150 km around the Noto peninsula that is probably interpreted as a fluid-rich region. We infer that fluids have been supplied from the uppermost mantle to the lower crust over a geological time scale and a large volume of fluids have accumulated below the seismogenic zone beneath the Noto peninsula. A further upward migration of fluids to the upper crust, which may have suddenly started in December 2020, probably triggers numerous earthquakes at depths of 10–15 km. Since major active faults exist at shallower extensions of the hypocenters of the Noto earthquake swarm, we consider that the earthquake swarm occurs along pre-existing and weak fault planes. Dense temporary seismic observations will highlight a smaller-scale (5–10 km) 3D seismic velocity model and finer hypocenter distribution, which provide additional information for better understanding of the generation mechanisms of the Noto earthquake swarm. Graphical Abstract

Željko Rozić

The paper presents one possibility of applying Object Oriented Modeling in the function of sustainable management of the wastewater drainage system. The applied technique (tool) for the implementation of systematic analysis, modeling, simulation and analysis of the obtained results is object-oriented modeling (OOM) and software package STELLA, which is adapted to complex and dynamic systems, such as wastewater drainage and treatment. The paper uses an already developed and applied model consisting of physical components of the system, the model of water quantity and water quality of the drainage system, and then also upgraded with part of the socio-economic system - the system of operating and maintenance costs. This methodological approach to modeling (using models) and imitating the real system (simulation), and analysis of the obtained results of the simulation flow, using OOM, proved to be a useful and effective tool for managing and analyzing sustainable management of urban drainage systems. A model and methodology is proposed for the analysis and wider application of complex urban water systems.

Janina Zaczek-Peplinska, Maria Elżbieta Kowalska, Edward Nowak

Periodic inventory and check surveys of the surfaces in engineering structures using terrestrial laser scanning require performing scans from many locations. The survey should be planned so as to obtain full coverage of the measured surface with a point cloud of appropriate density. Due to a variety of terrain obstacles in the close vicinity of the surveyed structure, structural and technical elements, as well as machinery and construction equipment (whose removal is impossible e.g. because of their role in the building and protection of the structure), it is often necessary to combine scans acquired from locations having different measurement geometry of the scene and performed in different lighting conditions. This makes it necessary to fill in blank spots with data of different spectral and geometric quality. This paper presents selected aspects of data harmonization in terrestrial laser scanning. The laser beam incidence angle and the scanning distance are assumed as parameters affecting the quality of the data. Based on the assumed minimum parameters for spectral data, an example of a harmonizing function for the concrete surface of a slurry wall was determined, and the methodology for determining its parameters was described. The presented solution for spectral data harmonization is based on the selection of reference fields representative of a given surface, and their classification with respect to selected geometric parameters of the registered point cloud. For geometric data, possible solutions to the harmonization problem have been analyzed, and criteria for point cloud reduction have been defined in order to obtain qualitatively consistent data. The presented results show that harmonization of point clouds obtained from different stations is necessary before their registration, in order to increase the reliability of analyses performed on the basis of check survey results in the assessment of the technical condition of a surface, its deformation, cracks and scratches.

Anurag KHANNA, Debasish BAGCHI, Suresh KANNAUJIYA et al.

The Gaurikund town falls on the way of the famous trekking route to Kedarnath that faced the wrath of the 2013 flood disaster. This fateful event severed more than 5000 casualties, demolished several infrastructures, and shifted the course of Gaurikund spring from its original position. Nevertheless, the Gaurikund geothermal spring system located in the Himalayan Geothermal Belt of the Garhwal region is preeminent for religious beliefs, balneotherapeutic values and a gateway to delve within the geothermal and hydrological characteristics of the area. In this perspective, restoration of Gaurikund geothermal spring system becomes a necessity. A multiparametric approach comprising geospatial, geology, hydrochemistry and geophysics has been used to study and justify these aspects at Gaurikund. The geological studies infer that the geothermal spring gets recharged by the steep, southerly dipping joints in granite gneiss. Subsequently, the deep percolated water heats up due to the high geothermal gradient and then emerge along the Vaikrita Thrust and its sympathetic minor fault-thrust system by advection. Moreover, four spring outlets are inventoried, with discharge varying from 7.46 to 95.54 L/min. The normal emissivity model uses the pre and post-disaster satellite data and generates maximum kinetic temperature images, showing a positive correlation between land surface temperature and spring discharge. Two-dimensional Electrical Resistivity Tomography (Schlumberger, Wenner and Gradient configurations) survey revealed two low resistivity zones proximal to the geothermal spring on the right bank of the Mandakini river. The engineering interventions carried out by bank protection and construction of small gully plugs in the catchment area is recommended along Gaurikund-Sonprayag section on the right bank of Mandakini river.

Malina Čvoro, Saša Čvoro, Una Okilj et al.

Modern technologies are evolving in the direction of energy efficiency and artificial light sources that today meet such targeted requirements have many other advantages that are not always recognized in planning. Utilizing the total capacity of energy efficient light sources requires a redesign and a different approach to public lighting planning. Using a small coverage along the river as a representative example, the possibilities of fulfilling the set strategic goal of the city development were presented through a proposal for redesign of urban lighting, and then the energy and economic justification of such a proposal was examined using the APEE method, which is also implemented in public lighting reconstruction in Banja Luka.

Mariyana Nikolova, Velimira Stoyanova, Desislava Varadzhakova et al.

The rich and diverse Natural Heritage of Bulgaria is a prerequisite for the development of nature- based tourism (NBT) of a new type. The research is carried out by the implementation of the ecosystem approach. The results include an assessment of the natural heritage capacity to provide goods and services for the development of NBT in the Tourist Regions (TR) of Bulgaria. The results show the spatial distribution of the natural heritage sites in all nine TR in Bulgaria and their natural capacity for development of different types of NBT. There are only 37 municipalities out of 265 with not a one Natural Heritage (NH) site, and all the rest have natural resources to develop NBT. The results can be of use for the achievement of the goals for sustainable tourism by assessment of the capacity to provide recreation ecosystem services (RES).

Christopher Blum, Johann Dambeck

Knowledge of the propagation of sensor errors in strapdown inertial navigation is crucial for the design of inertial and integrated navigation systems. The propagation of initialization errors and deterministic sensor errors is well covered in the literature. If considered at all, the propagation of inertial sensor noise has typically been assessed for un-correlated (white) Gaussian noise. Real inertial sensor noise, however, is time-correlated (colored) and best described by a combination of different stochastic processes. In this paper, we demonstrate how a navigation system’s response to colored noise input differs from the response to bias-like or white noise inputs. We present a method for assessing the navigation error from various inertial sensor noise processes without the need for time-consuming Monte Carlo simulations and demonstrate its application and validity with real sensor data. The proposed method is used to determine in which scenarios the sensor’s real noise can be approximated by simple white Gaussian noise. The results indicate that neglecting colored sensor noise is justified for many applications, but should be checked individually for each sensor configuration and mission.

Ajda Kafol Stojanović, Daniel Kozelj, Maruška Šubic Kovač

Settlement development depends on many factors, including the availability of municipal infrastructure. Scientists find that only integrated municipal infrastructure planning and settlement-development planning create conditions for sustainable and economical urban development. This is not taken into account in spatial planning practise in Slovenia. This paper seeks a response to the research question: Based on what data, and based on what model can the capacity of the water supply system in Slovenia be assessed, which constitutes the expert basis for settlement development decision-making at the local level. To this end, we analysed the results of relevant existing research and devised an appropriate integrated and dynamic model for assessing the capacity of the water supply system, which was generated from a simulation of construction on vacant building land and relevant water requirements of new water consumers. In assessing the capacity of the public water supply system, the Aquis 7.0 Software was applied in accomplishing the hydraulic system validation. In line with the hydraulic system validation results, the respective measures are proposed, and the costs of necessary improvements of the existing water supply system or its upgrading are envisaged. Based on the results obtained, the settlement-development stages can be determined. The model for assessing the capacity of the water supply system was applied to the example of the Municipality of Kranj.

Monika Sester

The increasing availability of devices to capture the position of moving objects (and other environmental information) leads to a very large amount and variety of mobility data. In order to obtain important information about the objects, their behavior or the environment of the objects, an automatic analysis is required. This article highlights current research questions in the context of the analysis of mobility data and presents them on the basis of work carried out at the Institute of Cartography and Geoinformatics (ikg) at Leibniz University of Hannover, Germany. A focus is put on the analysis and exploitation of information from Mobile Mapping vehicles.

Iz H. Bâki

This study provides additional information about the impact of atmospheric pressure on sea level variations. The observed regularity in sea level atmospheric pressure depends mainly on the latitude and verified to be dominantly random closer to the equator. It was demonstrated that almost all the annual and semiannual sea level variations at 27 globally distributed tide gauge stations can be attributed to the regional/local atmospheric forcing as an inverted barometric effect. Statistically significant non-linearities were detected in the regional atmospheric pressure series, which in turn impacted other sea level variations as compounders in tandem with the lunar nodal forcing, generating lunar sub-harmonics with multidecadal periods. It was shown that random component of regional atmospheric pressure tends to cluster at monthly intervals. The clusters are likely to be caused by the intraannual seasonal atmospheric temperature changes,which may also act as random beats in generating sub-harmonics observed in sea level changes as another mechanism. This study also affirmed that there are no statistically significant secular trends in the progression of regional atmospheric pressures, hence there was no contribution to the sea level trends during the 20th century by the atmospheric pressure.Meanwhile, the estimated nonuniform scale factors of the inverted barometer effects suggest that the sea level atmospheric pressure will bias the sea level trends inferred from satellite altimetry measurements if their impact is accounted for as corrections without proper scaling.

Драгана Тепић, Сандра Косић-Јеремић, Маја Илић

Jедан од основних задатака нацртне геометрије јесте да код студената развије визуелно разумијевање односа планиметријског и тродимензионалног цртежа, као и развијање просторне перцепције и логичког размишљања. Поставља се питање колико одређени екстерни фактори утичу на успјешноcт савладавањa градива из Нацртне геометрије. Од екстерних фактора је посматран утицај припремне наставе из нацртне геометрије и перспективе одржанe на Архитектонско-грађевинско-геодетском факултету у Бањој Луци, предзнање студената из ове области, знање математике и рачунарских предмета, као и познавање и кориштење програма за цртање. У циљу истраживања и прикупљања информација o овом проблему спроведена је анкета на узорку од 75 студената који су овај предмет слушали у протекле 4 године.