Multiple-point geostatistical reconstruction of GPR reflection data

2021 ◽  
Author(s):  
Chongmin Zhang ◽  
Mathieu Gravey ◽  
James Irving ◽  
Gregoire Mariethoz
Keyword(s):  
Conditional Simulation ◽  
Effective Means ◽  
Super Resolution ◽  
Multiple Point ◽  
High Resolution Data ◽  
Training Images ◽  
The Past ◽  
Reflection Data ◽  
Simulation Based ◽  
Reconstruction Strategy

<p>A common challenge in reflection GPR data processing and analysis is the reconstruction of missing traces. Gap filling, for example, may be needed to fill-in data where they could not be recorded in the field in order to produce a uniform trace spacing that is important for Fourier- or finite-difference-based migration methods. Similarly, field GPR data recorded in continuous mode with an uneven trace spacing are usually needed at a regular spacing for subsequent visualization and imaging. Finally, we may wish to increase the spatial resolution of a GPR dataset through “super-resolution”, whereby new traces are simulated between the existing ones in order to improve the interpretability of the data. A common challenge in these various applications is the need to interpolate a variable that has a complex, non-smooth behavior.</p><p>A number of interpolation methods have been proposed for filling in missing GPR traces over the past decades. The majority of these, however, tend to produce overly smooth and unrealistic results. Here, we present a data reconstruction strategy based on the QuickSampling (QS) multiple-point geostatistical method. With this approach, GPR traces are simulated via sequential conditional simulation based on patterns that are observed in nearby high-resolution data (training images). To evaluate the potential of our approach, we apply it to a variety of field 2D GPR datasets. Results indicate that the QS method provides an effective means of simulating missing GPR traces in a highly realistic manner.</p>

scholarly journals Multi-Task Optimization and Multi-Task Evolutionary Computation in the Past Five Years: A Brief Review

Mathematics ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 864
Author(s):  
Qingzheng Xu ◽  
Na Wang ◽  
Lei Wang ◽  
Wei Li ◽  
Qian Sun
Keyword(s):  
Evolutionary Computation ◽  
Explicit Knowledge ◽  
Optimization Problems ◽  
Effective Means ◽  
Typical Application ◽  
The Past ◽  
Current State ◽  
Evolution Algorithms ◽  
Application Fields

Traditional evolution algorithms tend to start the search from scratch. However, real-world problems seldom exist in isolation and humans effectively manage and execute multiple tasks at the same time. Inspired by this concept, the paradigm of multi-task evolutionary computation (MTEC) has recently emerged as an effective means of facilitating implicit or explicit knowledge transfer across optimization tasks, thereby potentially accelerating convergence and improving the quality of solutions for multi-task optimization problems. An increasing number of works have thus been proposed since 2016. The authors collect the abundant specialized literature related to this novel optimization paradigm that was published in the past five years. The quantity of papers, the nationality of authors, and the important professional publications are analyzed by a statistical method. As a survey on state-of-the-art of research on this topic, this review article covers basic concepts, theoretical foundation, basic implementation approaches of MTEC, related extension issues of MTEC, and typical application fields in science and engineering. In particular, several approaches of chromosome encoding and decoding, intro-population reproduction, inter-population reproduction, and evaluation and selection are reviewed when developing an effective MTEC algorithm. A number of open challenges to date, along with promising directions that can be undertaken to help move it forward in the future, are also discussed according to the current state. The principal purpose is to provide a comprehensive review and examination of MTEC for researchers in this community, as well as promote more practitioners working in the related fields to be involved in this fascinating territory.

SPECIAL ARTICLE

PEDIATRICS ◽  
1954 ◽  
Vol 14 (6) ◽  
pp. 668-672
Author(s):  
THOMAS H. LANMAN
Keyword(s):  
Effective Means ◽  
Surgical Service ◽  
Open Thoracotomy ◽  
Basic Principles ◽  
Children's Hospital ◽  
The Past ◽  
American Academy Of Pediatrics ◽  
Children’S Hospital ◽  
Surgical Field ◽  
Heavy Mortality

IT IS a great honor to be asked to present the first William E. Ladd Lecture before the American Academy of Pediatrics. This I appreciate and as this is the first lecture in my former Chief's honor, I shall devote my time more to Doctor Ladd and what he accomplished during his long and devoted service as Chief of the Surgical Service of the Boston Children's Hospital than to the presentation of anything new. In these days of great changes in the surgical field, it is very easy to overlook or even to forget the good things that were done in the past. I said "changes" rather than advances for some of the changes of today are not advances. It is easier to appreciate the extraordinary widening in the field of surgical endeavor that has been made possible by improvements in pre- and postoperative care, anesthesia, and the more effective means to combat infection than it is to remember what was done in a previous generation without such new and valuable aids. When I began my service at the Boston Children's Hospital in 1919, most of the deaths on the Surgical Service were caused by infection. Long surgical procedures involving an open thoracotomy were impossible. Prolonged operations on the gastrointestinal tract carried a heavy mortality largely because of our lack of knowledge of fluid balance. In those earlier days, an operation that exceeded an hour in length was considered to be entering a very dangerous phase. It is well, however, to review some of the types of cases done in those days and to keep in mind that the basic principles one had to follow at that time are still valid and that the good results of today are by no means entirely due to modern methods. Let me cite a few examples.

scholarly journals Nonlinear wavefront engineering with metasurface decorated quartz crystal

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ningbin Mao ◽  
Yutao Tang ◽  
Mingke Jin ◽  
Guanqing Zhang ◽  
Yang Li ◽  
...  
Keyword(s):  
Quartz Crystal ◽  
Second Harmonic ◽  
Super Resolution ◽  
Optical Efficiency ◽  
The Past ◽  
Nonlinear Photonic Crystals ◽  
Resolution Imaging ◽  
Wavefront Shaping ◽  
Hybrid Platform ◽  
Light Generation

Abstract In linear optical processes, compact and effective wavefront shaping techniques have been developed with the artificially engineered materials and devices in the past decades. Recently, wavefront shaping of light at newly generated frequencies was also demonstrated using nonlinear photonic crystals and metasurfaces. However, the nonlinear wave-shaping devices with both high nonlinear optical efficiency and high wave shaping efficiency are difficult to realize. To circumvent this constraint, we propose the idea of metasurface decorated optical crystal to take the best aspects of both traditional nonlinear crystals and photonic metasurfaces. In the proof-of-concept experiment, we show that a silicon nitride metasurface decorated quartz crystal can be used for the wavefront shaping of the second harmonic waves generated in quartz. With this crystal-metasurface hybrid platform, the nonlinear vortex beam generation and nonlinear holography were successfully demonstrated. The proposed methodology may have important applications in nonlinear structured light generation, super-resolution imaging, and optical information processing, etc.

scholarly journals Super-resolution imaging of negative-refractive graded-index photonic crystal flat lens

2021 ◽  
Author(s):  
Binming Liang ◽  
Xiao Huang ◽  
Jihong Zheng
Keyword(s):  
Photonic Crystal ◽  
Imaging System ◽  
Super Resolution ◽  
Point Sources ◽  
Image Resolution ◽  
Multiple Point ◽  
Single Image ◽  
Graded Index ◽  
Resolution Imaging ◽  
Flat Lens

Abstract Photonic crystal (PC) not only breaks through the diffraction limit of traditional lenses but also can realize super-resolution imaging. Improving the resolution is the key task of PC imaging. The main work of this paper is to use a graded-index Photonic crystal (GPC) flat lens to improve the image resolution. An air-hole type two-dimensional (2D) GPC structure based on silicon medium is proposed in this paper. Numerical simulations through RSoft reveal that when the medium in the imaging area is air, the full width at half maximum (FWHM) value of a single image reaches 0.362λ. According to the Rayleigh criterion, the images of two point sources 0.57λ apart can also be distinguished. In the imaging system composed of cedar oil and GPC flat lens, the FWHM value of a single image reaches 0.34λ. In addition, the images of multiple point sources 0.49λ apart can still be distinguished.

scholarly journals Optimum range of angle tracking radars: a theoretical computing

2019 ◽  
Vol 9 (3) ◽  
pp. 1765 ◽  
Author(s):  
Sadegh Samadi ◽  
Mohammad Reza Khosravi ◽  
Jafar A. Alzubi ◽  
Omar A. Alzubi ◽  
Varun G. Menon
Keyword(s):  
Closed Form ◽  
Optimization Problem ◽  
Tracking System ◽  
Total Error ◽  
Optimal Range ◽  
The Past ◽  
Simple Simulation ◽  
Simulation Based ◽  
Angle Tracking ◽  
Theoretical Computing

In this paper, we determine an optimal range for angle tracking radars (ATRs) based on evaluating the standard deviation of all kinds of errors in a tracking system. In the past, this optimal range has often been computed by the simulation of the total error components; however, we are going to introduce a closed form for this computation which allows us to obtain the optimal range directly. Thus, for this purpose, we firstly solve an optimization problem to achieve the closed form of the optimal range (Ropt.) and then, we compute it by doing a simple simulation. The results show that both theoretical and simulation-based computations are similar to each other.

scholarly journals Generation and Detection of Structured Light: A Review

2021 ◽  
Vol 9 ◽  
Author(s):  
Jian Wang ◽  
Yize Liang
Keyword(s):  
Quantum Information Processing ◽  
Structured Light ◽  
Super Resolution ◽  
Research Progress ◽  
Free Space Optical ◽  
The Past ◽  
Integrated Devices ◽  
Different Types ◽  
Resolution Imaging ◽  
Light Beams

Structured light beams have rapidly advanced over the past few years, from specific spatial-transverse/longitudinal structure to tailored spatiotemporal structure. Such beams with diverse spatial structures or spatiotemporal structures have brought various breakthroughs to many fields, including optical communications, optical sensing, micromanipulation, quantum information processing, and super-resolution imaging. Thus, plenty of methods have been proposed, and lots of devices have been manufactured to generate structured light beams by tailoring the structures of beams in the space domain and the space–time domain. In this paper, we firstly give a brief introduction of different types of structured light. Then, we review the recent research progress in the generation and detection of structured light on different platforms, such as free space, optical fiber, and integrated devices. Finally, challenges and perspectives are also discussed.

scholarly journals Super-resolution microscopy: successful applications in centrosome study and beyond

2019 ◽  
Vol 5 (5-6) ◽  
pp. 235-243 ◽  
Author(s):  
Jingyan Fu ◽  
Chuanmao Zhang
Keyword(s):  
Molecular Basis ◽  
Super Resolution ◽  
Diffraction Limit ◽  
Animal Cells ◽  
Microtubule Organizing Center ◽  
The Past ◽  
Eukaryotic Species ◽  
Organizing Center ◽  
Cilia And Flagella ◽  
Super Resolution Microscopy

AbstractCentrosome is the main microtubule-organizing center in most animal cells. Its core structure, centriole, also assembles cilia and flagella that have important sensing and motility functions. Centrosome has long been recognized as a highly conserved organelle in eukaryotic species. Through electron microscopy, its ultrastructure was revealed to contain a beautiful nine-symmetrical core 60 years ago, yet its molecular basis has only been unraveled in the past two decades. The emergence of super-resolution microscopy allows us to explore the insides of a centrosome, which is smaller than the diffraction limit of light. Super-resolution microscopy also enables the compartmentation of centrosome proteins into different zones and the identification of their molecular interactions and functions. This paper compiles the centrosome architecture knowledge that has been revealed in recent years and highlights the power of several super-resolution techniques.

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