Reflection of high-frequency acoustic signals from an air-sea interface with waves is considered in terms of determining travel times for acoustic tomography. Wave-induced, multi-path rays are investigated to determine how they influence the assumption that the time of the largest matched filter magnitude between the source and receiver signals is the best estimate of the arrival time of the flat-surface specular ray path. A simple reflection model is developed to consider the impact of in-plane, multi-path arrivals on the signal detected by a receiver. It is found that the number of multi-path rays between a source and receiver increases significantly with the number of times the ray paths strike the ocean surface. In test cases, there was always one of the multi-path rays that closely followed the flat-surface specular ray path. But all the multi-path rays arrive at the receiver almost simultaneously, resulting in interference with the signal from the flat-surface specular ray path. As a result, multi-path arrivals due to open ocean surface waves often distort the received signal such that maxima of matched filtering magnitudes will not always be a reliable indicator of the arrival time of flat-surface specular ray paths.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1121/1.2821974 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
A prior-information-based automatic segmentation method for the clinical target volume in adaptive radiotherapy of cervical cancer.
J Appl Clin Med Phys
May 2024
School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, China.
Objective: Adaptive planning to accommodate anatomic changes during treatment often requires repeated segmentation. In this study, prior patient-specific data was integrateda into a registration-guided multi-channel multi-path (Rg-MCMP) segmentation framework to improve the accuracy of repeated clinical target volume (CTV) segmentation.
Methods: This study was based on CT image datasets for a total of 90 cervical cancer patients who received two courses of radiotherapy.
Ceph-Net: automatic detection of cephalometric landmarks on scanned lateral cephalograms from children and adolescents using an attention-based stacked regression network.
BMC Oral Health
October 2023
Department of Oral Anatomy, Dental Research Institute, School of Dentistry, Seoul National University, Seoul, South Korea.
Background: The success of cephalometric analysis depends on the accurate detection of cephalometric landmarks on scanned lateral cephalograms. However, manual cephalometric analysis is time-consuming and can cause inter- and intra-observer variability. The purpose of this study was to automatically detect cephalometric landmarks on scanned lateral cephalograms with low contrast and resolution using an attention-based stacked regression network (Ceph-Net).
View Article and Find Full Text PDFPredicting particle deposition using a simplified 8-path in silico human lung prototype.
J Breath Res
July 2023
Facultad de Enfermería, Universidad de Oviedo, Instituto Nacional de Silicosis, and GRUBIPU-ISPA, Gijón, Spain.
Understanding particle deposition in the human lung is crucial for the assessment of environmental pollutants and the design of new drug delivery systems. Traditionally, research has been carried out by experimental analysis, but this generally requires expensive equipment and exposure of volunteers to radiation, resulting in limited data. To overcome these drawbacks, there is an emphasis on the development of numerical models capable of accurate predictive analysis.
View Article and Find Full Text PDFPrimary intracranial histiocytic sarcomas: a report of six cases and a pooled analysis of individual patient data.
J Cancer Res Clin Oncol
October 2023
Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
Objective: Primary intracranial histiocytic sarcomas (PIHSs) are extremely rare with limited reported cases, making their prognostic factors and management uncertain. This study aims to describe the clinical characteristics of PIHSs and propose a treatment protocol for this entity.
Methods: Clinical data were collected from six patients diagnosed with PIHSs at Beijing Tiantan Hospital between March 2011 and October 2022.
Indoor Visible Light Positioning System Based on Point Classification Using Artificial Intelligence Algorithms.
Sensors (Basel)
May 2023
School of Electronic Engineering, Beijing University of Posts and Telecommunications, Beijing 100876, China.
In RSSI-based indoor visible light positioning systems, when only RSSI is used for trilateral positioning, the receiver height needs to be known to calculate distance. Meanwhile, the positioning accuracy is greatly affected by multi-path effect interference, with the influence of the multi-path effect varying across different areas of the room. If only one single processing is used for positioning, the positioning error in the edge area will increase sharply.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!