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Synthetic aperture radar tomography (TomoSAR) has gained significant attention for three-dimensional (3D) imaging in urban environments. A notable limitation of traditional TomoSAR approaches is their primary focus on persistent scatterers (PSs), disregarding targets with temporal decorrelated characteristics. Temporal variations in coherence, especially in urban areas due to the dense population of buildings and artificial structures, can lead to a reduction in detectable PSs and suboptimal 3D reconstruction performance. The concept of partially coherent scatterers (PCSs) has been proven effective by capturing the partial temporal coherence of targets across the entire time baseline. In this study, an novel approach based on an iterative sub-network generation method is introduced to leverage PCSs for enhanced 3D reconstruction in dynamic environments. We propose a coherence constraint iterative variance analysis approach to determine the optimal temporal baseline range that accurately reflects the interferometric coherence of PCSs. Utilizing the selected PCSs, a 3D imaging technique that incorporates the iterative generation of sub-networks into the SAR tomography process is developed. By employing the PS reference network as a foundation, we accurately invert PCSs through the iterative generation of local star-shaped networks, ensuring a comprehensive coverage of PCSs in study areas. The effectiveness of this method for the height estimation of PCSs is validated using the TerraSAR-X dataset. Compared with traditional PS-based TomoSAR, the proposed approach demonstrates that PCS-based elevation results complement those from PSs, significantly improving 3D reconstruction in evolving urban settings. [ABSTRACT FROM AUTHOR]

The utilization of synthetic aperture radar tomography (TomoSAR) technology for the three-dimensional imaging of urban areas has garnered significant attention. In the case of multi-pass spaceborne TomoSAR, eliminating the atmospheric phase screen (APS) is a critical step. At present, a two-tier network method is widely employed for APS removal from extensive regions. However, challenges persist in the construction of first-tier reference networks using the Delaunay triangulation and bridge reference network methods, such as low network coverage ratios and linear correlation problems associated with near-parallel bridges. Consequently, a notable portion of the inversion results for buildings or artificial structures are either absent or characterized by low accuracy. To fully harness the observational information from all small connecting networks, this study introduces an improved bridge reference network construction method based on a region-growing strategy. This method merges small subnetworks with surrounding reference networks using high-quality bridge connections to maximize the coverage of the largest reference network. To validate the feasibility and effectiveness of the proposed approach, 27 TerraSAR-X images, which were collected in Shenzhen, China were utilized to construct a reference network and estimate building heights. The results clearly indicate that the proposed method effectively overcomes the limitations of existing methods.

The Vietnamese Mekong Delta (VMD) has been affected by environmental challenges for several decades, including coastal erosion and land subsidence. Subsidence rates of several cm/yr have been reported in parts of the delta, which are one order larger than the regional sea level rise of 3.3 mm/yr. The precise monitoring of subsidence with high spatial and temporal resolution is essential to understand its causes and associated risks, and to support the development and monitoring of countermeasures. Here, we present subsidence estimates between 2017 and 2022 derived from advanced persistent scatterer interferometry (PSI) applied to Sentinel-1 data. The PSI approach fully integrates temporary persistent scatterers, in order to derive the best possible persistent scatterer network for long time series. Furthermore, we adapted a method to optimally integrate reference points with known displacement to suppress spatially correlated nuisance (SCN) in the derived displacement time series. Due to a lack of geodetic references, we built an infrastructural reference network based on large bridges with piled foundations of about 70 m depth, which are only affected by compaction in deeper soil layers. We compare the method with the standard referencing approach in PSI, and show that referencing to the selected reference bridges with our method enables to measure the largest part of the subsidence while reducing the SCN considerably. We find the highest subsidence rates of more than 7 cm/yr mainly in urban areas, and various kinds of temporal nonlinearities.

The work used data on Saturn's satellite Hyperion obtained from the flight results of the Cassini spacecraft due to their completeness, resolution, and image quality. They pointed out the chaotic nature of Hyperion's rotation, as a result of which there was an ambiguity in determining its coordinate system associated with the body. The dimensions of the approximating ellipsoid and the parameters of the transition from the coordinate system, initially adopted under the assumption of uniform rotation of Hyperion around Saturn, to a coordinate system whose axes coincide with the axes of the found ellipsoid were obtained. A digital model of the Hyperion surface was also created, on the basis of which geodetic heights were calculated relative to a triaxial ellipsoid with certain parameters. The method for calculating heights is based on the combined use of the equation of the normal to the surface passing through a given point and the equation of the surface itself. As a result of the research, a map of Hyperion was compiled in the projection of the triaxial ellipsoid with horizontal lines constructed on the basis of calculated geodetic heights. An original method for studying the nature of Hyperion's rotation is presented using the projection of Saturn's position onto the surface of Hyperion for all known moments in time in an object-centric coordinate system. The implementation of this technique allowed us to assume that Hyperion's own rotation axis precesses relative to the largest axis of the body in a counterclockwise direction. [ABSTRACT FROM AUTHOR]

PPP-RTK (Precise Point Positioning – Real Time Kinematic) is a positioning method by GNSS (Global Navigation Satellite Systems), based on the SSR (State Space Representation) concept. One challenge for the fast convergence of PPP-RTK solutions in real-time applications is the mitigation of atmospheric effects (troposphere and ionosphere). Thus, using atmospheric models, PPP solutions can achieve accurate positions and shortened initialisation time. Such performance depends on the topology of permanent station networks and atmospheric conditions. The main objective of this contribution is to study the PPP-RTK and the optimised infrastructure in terms of costs and benefits to realise the method using atmospheric corrections. [ABSTRACT FROM AUTHOR]

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Publicly available grid datasets with electric steady-state equivalent circuit models are crucial for the development and comparison of a variety of power system simulation tools and algorithms. Such algorithms are essential to analyze and improve the integration of distributed energy resources (DERs) in electrical power systems. Increased penetration of DERs, new technologies, and changing regulatory frameworks require the continuous development of the grid infrastructure. As a result, the number and versatility of grid datasets, which are required in power system research, increases. Furthermore, the used grids are created by different methods and intentions. This paper gives orientation within these developments: First, a concise overview of well-known, publicly available grid datasets is provided. Second, background information on the compilation of the grid datasets, including different methods, intentions and data origins, is reviewed and characterized. Third, common terms to describe electric steady-state distribution grids, such as representative grid or benchmark grid, are assembled and reviewed. Recommendations for the use of these grid terms are made.

Signaling networks are involved in almost all major diseases such as cancer. As a result of this, understanding how signaling networks function is vital for finding new treatments for many diseases. Using gene knockdown assays such as RNA interference (RNAi) technology, many genes involved in these networks can be identified. However, determining the interactions between these genes in the signaling networks using only experimental techniques is very challenging, as performing extensive experiments is very expensive and sometimes, even impractical. Construction of signaling networks from RNAi data using computational techniques have been proposed as an alternative way to solve this challenging problem. However, the earlier approaches are either not scalable to large scale networks, or their accuracy levels are not satisfactory. In this study, we integrate RNAi data given on a target network with multiple reference signaling networks and phylogenetic trees to construct the topology of the target signaling network. In our work, the network construction is considered as finding the minimum number of edit operations on given multiple reference networks, in which their contributions are weighted by their phylogenetic distances to the target network. The edit operations on the reference networks lead to a target network that satisfies the RNAi knockdown observations. Here, we propose two new reference-based signaling network construction methods that provide optimal results and scale well to large-scale signaling networks of hundreds of components. We compare the performance of these approaches to the state-of-the-art reference-based network construction method SiNeC on synthetic, semi-synthetic, and real datasets. Our analyses show that the proposed methods outperform SiNeC method in terms of accuracy. Furthermore, we show that our methods function well even if evolutionarily distant reference networks are used. Application of our methods to the Apoptosis and Wnt signaling pathways recovers the known protein-protein interactions and suggests additional relevant interactions that can be tested experimentally. [ABSTRACT FROM AUTHOR]

Abstract: One of the challenges of brain network analysis is to directly compare network organization between subjects, irrespective of the number or strength of connections. In this study, we used minimum spanning tree (MST; a unique, acyclic subnetwork with a fixed number of connections) analysis to characterize the human brain network to create an empirical reference network. Such a reference network could be used as a null model of connections that form the backbone structure of the human brain. We analyzed the MST in three diffusion‐weighted imaging datasets of healthy adults. The MST of the group mean connectivity matrix was used as the empirical null‐model. The MST of individual subjects matched this reference MST for a mean 58%–88% of connections, depending on the analysis pipeline. Hub nodes in the MST matched with previously reported locations of hub regions, including the so‐called rich club nodes (a subset of high‐degree, highly interconnected nodes). Although most brain network studies have focused primarily on cortical connections, cortical–subcortical connections were consistently present in the MST across subjects. Brain network efficiency was higher when these connections were included in the analysis, suggesting that these tracts may be utilized as the major neural communication routes. Finally, we confirmed that MST characteristics index the effects of brain aging. We conclude that the MST provides an elegant and straightforward approach to analyze structural brain networks, and to test network topological features of individual subjects in comparison to empirical null models. [ABSTRACT FROM AUTHOR]

The ballastless track is a relatively new track construction built in Slovak Railways. The Department of Geodesy and the Department of Railway Building and Track Management of the University of Zilina have been involved in the research project aimed to monitor such an unconventional track construction. The periodical diagnostics of the vertical and positional geometrical track parameters is realized by absolute and relative methods to determine the construction conditions under traffic loading. Precision analysis of the observation is necessary to define confidential interval of measurements errors.

Evaluations of tidal wetland restoration efforts suffer from a lack of appropriate reference sites and standardized methods among projects. To help address these issues, the National Estuarine Research Reserve System (NERRS) and the NOAA Restoration Center engaged in a partnership to monitor ecological responses and evaluate 17 tidal wetland restoration projects associated with five reserves. The goals of this study were to (1) determine the level of restoration achieved at each project using the restoration performance index (RPI), which compares change in parameters over time between reference and restoration sites, (2) compare hydrologic and excavation restoration projects using the RPI, (3) identify key indicator parameters for assessing restoration effectiveness, and (4) evaluate the value of the NERRS as reference sites for local restoration projects. We found that the RPI, modified for this study, was an effective tool for evaluating relative differences in restoration performance; most projects achieved an intermediate level of restoration from 2008 to 2010, and two sites became very similar to their paired reference sites, indicating that the restoration efforts were highly effective. There were no differences in RPI scores between hydrologic and excavation restoration project types. Two abiotic parameters (marsh platform elevation and groundwater level) were significantly correlated with vegetation community structure and thus can potentially influence restoration performance. Our results highlight the value of the NERRS as reference sites for assessing tidal wetland restoration projects and provide improved guidance for scientists and restoration practitioners by highlighting the RPI as a trajectory analysis tool and identifying key monitoring parameters. [ABSTRACT FROM AUTHOR]

This paper presents an integrated analytical approach to estimate technical losses (TL) of medium voltage (MV) distribution network. The concept of energy flow in a radial MV distribution network is modelled using representative feeders (RF) characterized by feeder peak power demand, feeder length, load distribution, and load factor to develop the generic analytical TL equations. The TL estimation approach is applied to typical utility MV distribution network equipped with energy meters at transmission/distribution interface substation (TDIS) which register monthly inflow energy and peak power demand to the distribution networks. Additional input parameters for the TL estimation are from the feeder ammeters of the outgoing primary and secondary MV feeders. The developed models have been demonstrated through case study performed on a utility MV distribution network supplied from grid source through a TDIS with a registered total maximum demand of 44.9 MW, connected to four (4) 33 kV feeders, four (4) 33/11 kV 30 MVA transformers, and twelve (12) 11 kV feeders. The result shows close agreement with TL provided by the local power utility company. With RF, the approach could be extended and applied to estimate TL of any radial MV distribution network of different sizes and demography. [ABSTRACT FROM AUTHOR]

The IGS08 reference network, adopted by the International GNSS Service (IGS) in 2011, and IGS08 core network are both of primary importance for the international GNSS community. They were empirically designed so as to fulfill several standards, such as the quality of the ITRF2008 positions and velocities of the involved stations, the reliability of the data they provide, and their global distribution. The present study shows that such global reference networks and well-distributed sub-networks can be objectively and rigorously designed with genetic algorithms (global optimization stochastic algorithms), on the basis of equivalent criteria. The IGS08-like reference networks and IGS08 core-like sub-networks provided by genetic algorithms respectively outperform the IGS08 and IGS08 core networks for the specific criteria in play. This opens the way to future essential applications: objective design of the next IGS reference and core networks, construction of dynamic core networks, and computation of user-specific global or regional GNSS reference networks. [ABSTRACT FROM AUTHOR]

Highlights: [•] This study assesses vineyard soil quality in a regional-scale, yet terroir-specific for contextualized evaluations of management techniques. [•] A large data set of 164 vineyard plots and 31 indicators. [•] Biological activity in vineyards was low, but no systematic perturbation of the trophic web was noticed. [•] Invariant soil properties explained up to 25% of the variance of dynamic chemical and biological parameters. [•] We offer extensive references through a large dataset of dynamic indicators tabulated according to use-invariant soil properties. [ABSTRACT FROM AUTHOR]