Three-dimensional Localization Research Articles

Prediction for Water Inrush Disaster Source and CFD-Based Design of Evacuation Routes in Karst Tunnel

Tunnel construction in mountain areas, especially in karst regions, is challenging due to complex hydrogeological conditions in such regions, such as water inrush disaster induced by water-bearing structures that may jeopardize tunnel construction safety. To identify potential water inrush sources, this study first analyzed regional hydrogeological conditions of the Yuelongmen tunnel that cross under the river. Then, the tunnel-induced polarization method was employed to probe three-dimensional (3D) spatial location and distribution of water-rich areas. Based on detection results, numerical simulation was carried out to study the corresponding velocity and pressure for each probing line set in the numerical model, and flow characteristics after water inrush were summarized. Finally, optimized evacuation routes were designed to minimize the potential damage caused by the water inrush. Research results may provide critical implications for water inrush analysis and reduce casualties during tunneling in karst regions in China.

Using global optimization methods for three-dimensional localization and quantification of incoherent acoustic sources.

Complex acoustic systems typically present three-dimensional distributions of noise sources. Conventional acoustic imaging methods with planar microphone arrays are unsuitable for three-dimensional acoustic imaging, given the computational demands and the incapability to explicitly account for the presence of multiple sources. This paper proposes the use of global optimization methods to solve these shortcomings. An experiment with three incoherent speakers proved that this method can accurately determine the three-dimensional location and the respective sound level of each individual source. In addition, super-resolution is achieved beyond half the Rayleigh resolution limit.

Optimal precision and accuracy in 4Pi-STORM using dynamic spline PSF models

Coherent fluorescence imaging with two objective lenses (4Pi detection) enables single-molecule localization microscopy with sub-10 nm spatial resolution in three dimensions. Despite its outstanding sensitivity, wider application of this technique has been hindered by complex instrumentation and the challenging nature of the data analysis. Here we report the development of a 4Pi-STORM microscope, which obtains optimal resolution and accuracy by modeling the 4Pi point spread function (PSF) dynamically while also using a simpler optical design. Dynamic spline PSF models incorporate fluctuations in the modulation phase of the experimentally determined PSF, capturing the temporal evolution of the optical system. Our method reaches the theoretical limits for precision and minimizes phase-wrapping artifacts by making full use of the information content of the data. 4Pi-STORM achieves a near-isotropic three-dimensional localization precision of 2–3 nm, and we demonstrate its capabilities by investigating protein and nucleic acid organization in primary neurons and mammalian mitochondria.

SEAFLOOR POSITIONING MODEL FOR SIMULTANEOUS ESTIMATION OF SOUND VELOCITY

Abstract. The spatial and temporal change of sound speed has a significant impact on the accuracy of GNSS-A underwater positioning. However, it is hard to collect enough data to cover all the spatial and temporal changes of sound velocity. We built an acoustic ranging model that included the sound velocity component, and then we looked at how the model could be used for three-dimensional seabed location and undersea crust monitoring. Meanwhile, B-spline curves are used to construct a sound velocity model that encompasses temporal variation as well as two-dimensional spatial gradients. The method was utilized to assess the simulated data and the in-situ data collected in July 2019, respectively. Simulation results show that the root mean square of the horizontal coordinates solved by the ranging model is less than 10 cm, and the model may meet the demands of subsea crust monitoring under certain situations. In the real data experiment, the square root of variance of the coordinate was better than 10 cm. The sound velocity model findings indicated that the variance of sound velocity in the experimental marine region was less than 1m/s, with clear daily patterns and short-period variations. The algorithm does not need the sound velocity profile information and can save the measurement time of the sound velocity profile.

Coronal brain atlas in stereotaxic coordinates of the African spiny mouse, Acomys cahirinus.

The African spiny mouse (Acomys cahirinus) is an emerging model of mammalian epimorphic regeneration that has aroused the interest of the scientific community in the last decade. To date, studies on brain repair have been hindered by the lack of knowledge on the neuroanatomy of this species. Here, we present a coronal brain atlas in stereotaxic coordinates, which allows for three-dimensional identification and localization of the brain structures of this species. The brain of 12-week-old spiny mice was mapped in stereotaxic coordinates using cresyl violet-stained brain sections obtained from coronal cryosectioning of the brain after transcardial perfusion with fixative. The atlas is presented in 42 plates representing sections spaced 240 μm apart. Stereotaxic coordinates were validated using both a model of Parkinsonian lesion of the striatum with 6-hydroxydopamine and labeling of the corticospinal tract in the spiny mouse spinal cord using AAV1/2-GFP intracortical injections. This work presents a new tool in A. cahirinus neurobiology and opens new avenues of research for the investigation of the regenerative ability of A. cahirinus in models of brain disorders.

A standard siren cosmological measurement from the potential GW190521 electromagnetic counterpart ZTF19abanrhr

ABSTRACT The identification of the electromagnetic (EM) counterpart candidate ZTF19abanrhr to the binary black hole merger GW190521 opens the possibility to infer cosmological parameters from this standard siren with a uniquely identified host galaxy. The distant merger allows for cosmological inference beyond the Hubble constant. Here, we show that the three-dimensional spatial location of ZTF19abanrhr calculated from the EM data remains consistent with the latest sky localization of GW190521 provided by the LIGO-Virgo Collaboration. If ZTF19abanrhr is associated with the GW190521 merger, and assuming a flat wCDM model, we find that $H_0=48^{+23}_{-10}\, \mathrm{km} \, \mathrm{s}^{-1}\, \mathrm{Mpc}^{-1}$, $\Omega _m=0.35^{+0.41}_{-0.26}$, and $w_0=-1.31^{+0.61}_{-0.48}$ (median and $68{{\ \rm per\ cent}}$ credible interval). If we use the Hubble constant value inferred from another gravitational-wave event, GW170817, as a prior for our analysis, together with assumption of a flat ΛCDM and the model-independent constraint on the physical matter density ωm from Planck, we find $H_0=68.9^{+8.7}_{-6.0}\, \mathrm{km} \, \mathrm{s}^{-1}\, \mathrm{Mpc}^{-1}$.

Experimental Analysis of Ultra-High-Frequency Signal Propagation Paths in Power Transformers

Ultra-high-frequency (UHF) partial discharge (PD) monitoring is gaining popularity because of its advantages over electrical methods for onsite/online applications. One such advantage is the possibility of three-dimensional PD source localization. However, it is necessary to understand the signal propagation and attenuation characteristics in transformers to improve localization. Since transformers are available in a wide range of ratings and geometric sizes, it is necessary to ascertain the similarities and differences in UHF signal characteristics across the different designs. Therefore, in this contribution, the signal attenuation and propagation characteristics of two 300 MVA transformers are analyzed and compared based on experiments. The two transformers have the same rating but different internal structures. It should be noted that the oil is drained out of the transformers for these tests. Additionally, a simulation model of one of the transformers is built and validated based on the experimental results. Subsequently, a simulation model is used to analyze the electromagnetic wave propagation inside the tank. Analysis of the experimental data shows that the distance-dependent signal attenuation characteristics are similar in the case of both transformers and can be well represented by hyperbolic equations, thus indicating that transformers with the same rating have similar attenuation characteristics even if they have different internal structures.

The Learning Curve and Inter-Observer Variability in Contouring the Hippocampus under the Hippocampal Sparing Guidelines of Radiation Therapy Oncology Group 0933.

Hippocampal-sparing brain radiotherapy (HS-BRT) in cancer patients results in preservation of neurocognitive function after brain RT which can contribute to patients’ quality of life (QoL). The crucial element in HS-BRT treatment planning is appropriate contouring of the hippocampus. Ten doctors delineated the left and right hippocampus (LH and RH, respectively) on 10 patients’ virtual axial images of brain CT fused with T1-enhanced MRI (1 mm) according to the RTOG 0933 atlas recommendations. Variations in the spatial localization of the structure were described in three directions: right–left (X), cranio-caudal (Y), and forward–backward (Z). Discrepancies concerned three-dimensional localization, shape, volume and size of the hippocampus. The largest differences were observed in the first three delineated cases which were characterized by larger hippocampal volumes than the remaining seven cases. The volumes of LH of more than half of hippocampus contours were marginally bigger than those of RH. Most differences in delineation of the hippocampus were observed in the area of the posterior horn of the lateral ventricle. Conversely, a large number of hippocampal contours overlapped near the brainstem and the anterior horn of the lateral ventricle. The most problematic area of hippocampal contouring is the posterior horn of the lateral ventricle. Training in the manual contouring of the hippocampus during HS-BRT treatment planning under the supervision of experienced radiation oncologists is necessary to achieve optimal outcomes. This would result in superior outcomes of HS-BRT treatment and improvement in QoL of patients compared to without HS-BRT procedure. Correct delineation of the hippocampus is problematic. This study demonstrates difficulties in HS-BRT treatment planning and highlights critical points during hippocampus delineation.

Modeling and probabilistic analysis of civil aircraft operational risk for suborbital disintegration accidents.

To reduce the collision risk to civil airliners caused by suborbital vehicle disintegration events, this paper uses a covariance propagation algorithm to model the debris landing point of suborbital disintegration accidents and gives a collision probability analysis method for civil airliners encountering debris during the cruise. Collision warning is performed for airborne risk targets to improve the emergency response capability of the ATC surveillance system to hazardous situations. The algorithm models the three-dimensional spatial motion target localization problem as a Gauss-Markov process, quantifying the location of debris landing points in the vicinity of nominal trajectories. By predicting the aircraft trajectory, the calculation of the inter-target collision probability is converted into an integration problem of a two-dimensional normally distributed probability density function in a circular domain. Compared with the traditional Monte Carlo method, the calculation speed of debris drop points is improved, which can meet the requirements of civil aviation for real-time response to unexpected situations.

Integration of 3DGIS and BIM and its application in visual detection of concealed facilities

ABSTRACT The multi-level modeling technology of Building Information Modeling (BIM), combined with Three-dimensional Geographic Information System (3DGIS) macro-scene visualization technology and location information, can realize the transmission of decentralized information from various disciplines to multi-disciplinary collaborative information sharing services. It can be applied independently for the whole life cycle, which plays a positive role in reducing the cost and improving the efficiency of engineering planning, design, construction, operation, and maintenance. In this paper, the data integration and function integration methods of 3DGIS and BIM are designed. In order to avoid the breaking problems caused by attribute information loss and excessive simplification in the process of BIM data integration, the attribute mapping between 3DGIS and BIM based on Industry Foundation Classes (IFC) and City Geography Markup Language (CityGML) and the data simplification method considering the geometric characteristics of BIM are designed. By setting the relevant preconditions and thresholds of patch merging, on the premise of maintaining the structural characteristics of BIM data surface, reduce the amount of model data to improve the efficiency of BIM data loading, rendering and display effect in 3D geospatial scene. Through the data and function integration of 3DGIS and BIM, we can effectively manage the data of large-scale model, and calculate and obtain the geospatial location and direction of key parts of buildings through the coordinate transformation of BIM, which can effectively assist the rapid and accurate positioning of BIM in virtual 3D scene and expand the visualization ability of 3DGIS. By effectively integrating 3DGIS and BIM, this paper gives full play to the spatial management advantages of 3DGIS and the component management advantages of BIM. The rationality and operability of the method are verified by its application in the operation and maintenance management project of concealed facilities in actual buildings.

利用方向矢量分解的近场及严格非圆信源三维定位

利用方向矢量分解的近场及严格非圆信源三维定位

Four-dimensional multi-particle tracking in living cells based on lifetime imaging

Abstract Research on dynamic events in living cells, such as intracellular transportation, is important for understanding cell functions. As movements occur within cells, the microenvironment of the moving vesicles or biomacromolecules may affect the behavior of them. Herein, we propose a method of simultaneously monitoring changes in spatial positions and the local environment related to the fluorescence lifetime, i.e., four-dimensional (4D) multi-particle parallel-tracking in living cells. Based on double-helix point spread function (DH-PSF) microscopy and streak camera, the method combines three-dimensional (3D) localization methods and fluorescence lifetime imaging. By modifying the PSF of the system, the 3D positions and fluorescence lifetime information for several molecules within a depth of a few microns can be acquired simultaneously from a single snapshot. The feasibility of this method is verified by simulating the real-time tracking of a single particle with a given trajectory. In addition, a proof-of-concept 4D tracking system based on the DH-PSF and streak camera was built. The experimental results show that the 3D localization and lifetime precision are σ(x, y, z) = (26 nm, 35 nm, 53 nm) and σ(τ) = 103 ps, respectively, and the effective depth of field is approximately 4 μm. Finally, intracellular endocytosis in a living cell was observed using the system, which demonstrated the successful 4D tracking of two microspheres moving within an axial depth of 4 μm. This work opens a new perspective for research of dynamic processes, by providing information about the chemical (microenvironments) and physical (positions) changes of moving targets in living cells.

Deep tissue localization and sensing using optical microcavity probes

Optical microcavities and microlasers were recently introduced as probes inside living cells and tissues. Their main advantages are spectrally narrow emission lines and high sensitivity to the environment. Despite numerous novel methods for optical imaging in strongly scattering biological tissues, imaging at single-cell resolution beyond the ballistic light transport regime remains very challenging. Here, we show that optical microcavity probes embedded inside cells enable three-dimensional localization and tracking of individual cells over extended time periods, as well as sensing of their environment, at depths well beyond the light transport length. This is achieved by utilizing unique spectral features of the whispering-gallery modes, which are unaffected by tissue scattering, absorption, and autofluorescence. In addition, microcavities can be functionalized for simultaneous sensing of various parameters, such as temperature or pH value, which extends their versatility beyond the capabilities of standard fluorescent labels.

"Orphan" Connexin43 in Plakophilin-2 Deficient Hearts Revealed by Volume Electron Microscopy.

Previous studies revealed an abundance of functional Connexin43 (Cx43) hemichannels consequent to loss of plakophilin-2 (PKP2) expression in adult murine hearts. The increased Cx43-mediated membrane permeability is likely responsible for excess entry of calcium into the cells, leading to an arrhythmogenic/cardiomyopathic phenotype. The latter has translational implications to the molecular mechanisms of inheritable arrhythmogenic right ventricular cardiomyopathy (ARVC). Despite functional evidence, visualization of these “orphan” (i.e., non-paired in a gap junction configuration) Cx43 hemichannels remains lacking. Immuno-electron microscopy (IEM) remains an extremely powerful tool to localize, with nanometric resolution, a protein within its native structural landscape. Yet, challenges for IEM are to preserve the antigenicity of the molecular target and to provide access for antibodies to reach their target, while maintaining the cellular/tissue ultrastructure. Fixation is important for maintaining cell structure, but strong fixation and vigorous dehydration (as it is routine for EM) can alter protein structure, thus impairing antigen-antibody binding. Here, we implemented a method to combine pre-embedding immunolabeling (pre-embedding) with serial block-face scanning electron microscopy (SBF-SEM). We utilized a murine model of cardiomyocyte-specific, Tamoxifen (TAM) activated knockout of PKP2. Adult hearts were harvested 14 days post-TAM, at this time hearts present a phenotype of concealed ARVC (i.e., an arrhythmogenic phenotype but no overt structural disease). Thick (200 µm) vibratome slices were immunolabelled for Cx43 and treated with nanogold or FluoroNanogold, coupled with a silver enhancement. Left or right ventricular free walls were dissected and three-dimensional (3D) localization of Cx43 in cardiac muscle was performed using SBF-SEM. Reconstructed images allowed us to visualize the entire length of gap junction plaques, seen as two parallel, closely packed strings of Cx43-immunoreactive beads at the intercalated disc. In contrast, in PKP2-deficient hearts we observed bulging of the intercellular space, and entire areas where only one of the two strings could be observed, indicating the presence of orphan Cx43. We conclude that pre-embedding and SBF-SEM allowed visualization of cardiac Cx43 plaques in their native environment, providing for the first time a visual complement of functional data indicating the presence of orphan Cx43 hemichannels resulting from loss of desmosomal integrity in the heart.

Facilitation of Pediatric Posterior Fossa Vascular Malformation Resection Using Virtual Reality Platform: 2-Dimensional Operative Video.

Pediatric posterior fossa arteriovenous malformations (AVMs) are rare entities that pose significant cumulative lifetime risk of rupture and require treatment. Microsurgical resection remains a good option for definitively treating posterior fossa AVMs in one setting. The drawback of endovascular embolization is the lower rates of nidus obliteration. Although stereotactic radiosurgery is a safe alternative, it takes several years to achieve the treatment goal all the while predisposing the patient to the risk of AVM rupture.1,2 Accurate localization and visualization remain challenging for microsurgical treatment of posterior fossa AVMs.3-5 Small size of a nidus, prone position, and proximity to eloquent areas make these lesions particularly difficult to localize and resect. We present the operative case of a 6-year-old boy with a small, ruptured posterior fossa AVM. After undergoing hematoma evacuation, the patient underwent microsurgical resection of a small right vermian AVM assisted by the virtual reality platform, Surgical Theater (Gates Mills, OH). Our video demonstrates the utility of a virtual augmented reality platform for addressing the challenges posed by a small posterior fossa AVM with respect to the need for precise three-dimensional localization of small lesions. The patient consented to the procedure. The participants and any identifiable individuals consented to publication of his/her image.

The patterns and spatial locations of local recurrence in breast cancer with implant-based reconstruction after mastectomy

Background and purposeThe European Society for Radiotherapy and Oncology (ESTRO) recently defined delineation guidelines for the clinical target volume for postmastectomy radiation therapy (PMRT) after immediate implant-based reconstruction for early-stage breast cancer. We analyzed the three-dimensional location and pattern of local recurrence in accordance with the reconstruction type and ESTRO-target volume. Materials and methodsThis retrospective study involved patients who had undergone mastectomy with implant reconstruction between 2010 and 2019 and who had local recurrence as the first event. For mapping analysis, one subpectoral and one prepectoral implant patient were selected. All recurrence lesions were contoured and mapped in a representative case. ResultsA total of 1327 patients with breast cancer who underwent mastectomy and implant-based breast reconstruction were identified; 51 were enrolled with a total of 65 lesions. In subpectoral implant patients, 93% of recurrences were located in the ESTRO-target volume. No recurrence occurred in the implant pocket, but 7% of the recurrent tumors developed in the pectoralis major and deep thoracic muscle. In prepectoral implant patients, all recurrent tumors occurred within the ESTRO-target volume. ConclusionThe ESTRO-target volume in PMRT after reconstruction encompassed most local recurrences in patients who underwent mastectomy with immediate implant reconstruction. Our results support the application of the ESTRO Advisory Committee for Radiation Oncology Practice consensus guideline for target volume of PMRT after immediate implant-based reconstruction for early-stage breast cancer.

Three-dimensional localization of gas leakage using acoustic holography

Gas leakage localization is essential to prevent accidents from gas transportation or storage failures. There have been extensive studies on one-dimensional (1D) and two-dimensional (2D) gas leakage localization problem. This paper is the first to report the demonstration of a three-dimensional (3D) localization of gas leaks using far-field acoustic holography. This approach simultaneously provides 2D sound field imaging and depth position information regarding the leakage source. A virtual phased array composed of only two sensors collects the needed data, resulting in improved accuracy, enhanced feasibility and reduced cost. Various parameters, including the number of sensors, the spacing of array elements and the distance to the leakage source, are analyzed by a simulation of leakage sound field reconstruction. A series of experiments validated the effectiveness and accuracy of the proposed approach. Our results demonstrate that the proposed method achieves 3D localization and high-resolution imaging recognition of gas leaks.

Computer Vision-Based Path Planning for Robot Arms in Three-Dimensional Workspaces Using Q-Learning and Neural Networks.

Computer vision-based path planning can play a crucial role in numerous technologically driven smart applications. Although various path planning methods have been proposed, limitations, such as unreliable three-dimensional (3D) localization of objects in a workspace, time-consuming computational processes, and limited two-dimensional workspaces, remain. Studies to address these problems have achieved some success, but many of these problems persist. Therefore, in this study, which is an extension of our previous paper, a novel path planning approach that combined computer vision, Q-learning, and neural networks was developed to overcome these limitations. The proposed computer vision-neural network algorithm was fed by two images from two views to obtain accurate spatial coordinates of objects in real time. Next, Q-learning was used to determine a sequence of simple actions: up, down, left, right, backward, and forward, from the start point to the target point in a 3D workspace. Finally, a trained neural network was used to determine a sequence of joint angles according to the identified actions. Simulation and experimental test results revealed that the proposed combination of 3D object detection, an agent-environment interaction in the Q-learning phase, and simple joint angle computation by trained neural networks considerably alleviated the limitations of previous studies.

3D Lightning Location Method Based on Range Difference Space Projection

Most lightning location networks obtain the position results by optimizing the goodness of fit to determine that all combinatorial time differences of arrivals (TDOAs) are due to a common discharge. This paper proposes a three-dimensional (3D) lightning location method based on range difference (RD) space projection. The proposed method projects all the measurements into the RD space, which has the space-invariant feature of the equivalence cell and can be partitioned soundly. Aiming at the problem of computational cost of the procedure of the projection, the hierarchical strategy is proposed to improve computational efficiency. The performance of the RD space projection based on the hierarchical strategy is analyzed via Monte-Carlo simulations. The results show that the proposed method can locate lightning sources in real time with high accuracy. The results also show that the location accuracy is limited by the level of the inherent time uncertainty, the layout, and the size of the receiver network. Under the fixed layout and size of the receiver network, and the fixed measurement noise uncertainty, the positioning precision cannot be improved more even if the grid step is small enough or the number of receivers is large enough.

Spatially modulated illumination microscopy: application perspectives in nuclear nanostructure analysis

Thousands of genes and the complex biochemical networks for their transcription are packed in the micrometer sized cell nucleus. To control biochemical processes, spatial organization plays a key role. Hence the structure of the cell nucleus of higher organisms has emerged as a main topic of advanced light microscopy. So far, a variety of methods have been applied for this, including confocal laser scanning fluorescence microscopy, 4Pi-, STED- and localization microscopy approaches, as well as (laterally) structured illumination microscopy (SIM). Here, we summarize the state of the art and discuss application perspectives for nuclear nanostructure analysis of spatially modulated illumination (SMI). SMI is a widefield-based approach to using axially structured illumination patterns to determine the axial extension (size) of small, optically isolated fluorescent objects between less than or equal to 200 nm and greater than or equal to 40 nm diameter with a precision down to the few nm range; in addition, it allows the axial positioning of such structures down to the 1 nm scale. Combined with SIM, a three-dimensional localization precision of less than or equal to 1 nm is expected to become feasible using fluorescence yields typical for single molecule localization microscopy applications. Together with its nanosizing capability, this may eventually be used to analyse macromolecular complexes and other nanostructures with a topological resolution, further narrowing the gap to Cryoelectron microscopy. This article is part of the Theo Murphy meeting issue ‘Super-resolution structured illumination microscopy (part 2)’.