scholarly journals A Reference Spectrum Model for Estimating Source Levels of Marine Shipping Based on Automated Identification System Data

2021 ◽  
Vol 9 (4) ◽  
pp. 369 ◽  
Author(s):  
Alexander MacGillivray ◽  
Christ de Jong
Keyword(s):  
Objective Assessment ◽  
Noise Pollution ◽  
Specific Reference ◽  
Identification System ◽  
Reference Spectrum ◽  
Underwater Sound ◽  
The North ◽  
Joint Monitoring ◽  
Source Level ◽  
Spectrum Model

Underwater sound mapping is increasingly being used as a tool for monitoring and managing noise pollution from shipping in the marine environment. Sound maps typically rely on tracking data from the Automated Information System (AIS), but information available from AIS is limited and not easily related to vessel noise emissions. Thus, robust sound mapping tools not only require accurate models for estimating source levels for large numbers of marine vessels, but also an objective assessment of their uncertainties. As part of the Joint Monitoring Programme for Ambient Noise in the North Sea (JOMOPANS) project, a widely used reference spectrum model (RANDI 3.1) was validated against statistics of monopole ship source level measurements from the Vancouver Fraser Port Authority-led Enhancing Cetacean Habitat and Observation (ECHO) Program. These validation comparisons resulted in a new reference spectrum model (the JOMOPANS-ECHO source level model) that retains the power-law dependence on speed and length but incorporates class-specific reference speeds and new spectrum coefficients. The new reference spectrum model calculates the ship source level spectrum, in decidecade bands, as a function of frequency, speed, length, and AIS ship type. The statistical uncertainty (standard deviation of the deviation between model and measurement) in the predicted source level spectra of the new model is estimated to be 6 dB.

OPTIMIZATION OF SURGICAL-ORTHODONTIC TREATMENT TACTICS IN PATIENTS WITH IMPACTED TEETH

2019 ◽  
Vol 72 (5) ◽  
pp. 838-845
Author(s):  
Pavlo I. Tkachenko ◽  
Maryna I. Dmytrenko ◽  
Mykola O. Cholovskyi
Keyword(s):  
Orthodontic Treatment ◽  
Objective Assessment ◽  
Optimal Path ◽  
Reference Points ◽  
Permanent Teeth ◽  
Diagnostic Process ◽  
Specific Reference ◽  
Dental Arch ◽  
Impacted Tooth ◽  
Impacted Teeth

Introduction: Impacted teeth is complex anomaly of teeth eruption that requires a balanced approach not only in the differential diagnosis of its forms, but choice of rational methods of treatment. The aim: Optimization of the tactics of orthodontic-surgical treatment of patients with impacted teeth based on the development and implementation of computed tomographic indices (KT) and photometric indices (FM) of opening of surgical access (OSA) to crowns of impacted teeth Materials and methods: The results of treatment of 48 patients with delay of permanent teeth eruption have been analyzed. For an objective assessment of treatment results, a group of 24 (aged from 9 to 19 years old ) was formed. All 24 patients had typical clinical situation. Results: Orthodontic correction of patients envisaged, first of all, the elimination of obstacles in the way of teeth eruption, if necessary to provide space in dental arch and simultaneous treatment of associated bite malocclusions. Surgical exposure of impacted tooth crown was carried out and at the same time a triangular shaped guiding channel was formed, base of channel was at the impacted tooth and its angle finished into the dental arch. Precise dimensions and depth of the channel were preliminary planed on computed tomography slices with 3D reconstruction. Mean values of CT width (7,13±0,54mm), and length (6,42±0,78mm) of OSA and CT index (130,79±8,19%) of OSA to impacted teeth crowns were determined. Conclusion: To improve the quality of diagnosis and optimization of methodological approaches to treatment of patients with teeth impaction, we have proposed CT and FM OSA indices to the crowns of impacted teeth. The developed indices serve as specific reference points for optimization of diagnostic process, for reducing of probability of repeated surgical interventions and choosing the optimal path for instrumental orthodontic treatment of patients with impacted teeth

scholarly journals Hindcasting Soundscapes before and during the COVID-19 Pandemic in Selected Areas of the North Sea and the Adriatic Sea

2021 ◽  
Vol 9 (7) ◽  
pp. 702
Author(s):  
Hüseyin Özkan Sertlek
Keyword(s):  
North Sea ◽  
Adriatic Sea ◽  
Propagation Model ◽  
The North ◽  
Fishing Vessels ◽  
Water Test ◽  
The North Sea ◽  
Monthly Changes ◽  
Source Level ◽  
Sound Maps

The national measures in several European countries during the COVID-19 pandemic also affected offshore human activities, including shipping. In this work, the temporal and spatial variations of shipping sound are calculated for the years before and during the pandemic in selected shallow water test areas from the Southern North Sea and the Adriatic Sea. First, the monthly sound pressure level maps of ships and wind between 2017 and 2020 are calculated for frequencies between 100 Hz to 10 kHz. Next, the monthly changes in these maps are compared. The asymptotic approximation of the hybrid flux-mode propagation model reduces the computational requirements for sound mapping simulations and facilitates the production of a large number of sound maps for different months, depths, frequencies, and ship categories. After the strictest COVID-19 measures were applied in April 2020, the largest decline was observed for the fishing, passenger and recreational ships. Although the changes in the number of fishing vessels are large, their contribution to the soundscape is minor due to their low source level. In both test areas, the spatial exceedance levels and acoustic energies were decreased in 2020 compared to the average of the previous three years.

scholarly journals Positioning Error Analysis of Ranging-Mode Using AIS Signals in China

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Kai Zheng ◽  
Qing Hu ◽  
Jingbo Zhang
Keyword(s):  
Measurement Errors ◽  
Phase Locking ◽  
Automatic Identification ◽  
Identification System ◽  
Time Of Arrival ◽  
Positioning Error ◽  
North East ◽  
The North ◽  
Error Distributions ◽  
Shift Keying

In order to provide resilient position, navigation, and time (PNT) information forE-Navigation, the ranging-mode (R-Mode) positioning using automatic identification system (AIS) signals is encouraged. As the accuracy is the key for the positioning system, this paper investigates the position error of the R-Mode positioning based on AIS shore-based station in China. The measurement errors of Gaussian filtered minimum shift keying (GMSK) demodulation based on carrier phase locking loop are investigated in theory. The dilution of precision (DOP) for time of arrival (TOA) and time difference of arrival (TDOA) used in R-Mode positioning of AIS is discussed in two measurement mechanisms. The positioning error distributions in the North, East, and South Sea regions of China based on the existing AIS shore-based stations are evaluated. The positioning accuracy is at the meter level in the most traffic dense areas to meet the requirements for vessel navigation.

The Automated Risk Estimation for the Navigation of Autonomous Ships by Learning with Navigation Feature

2020 ◽  
pp. 2041003
Author(s):  
Wei Chian Tan ◽  
Kie Hian Chua ◽  
Yanling Wu
Keyword(s):  
Nearest Neighbor ◽  
Dimensional Space ◽  
Risk Estimation ◽  
Nearest Neighbor Search ◽  
Mathematical Representation ◽  
Automatic Identification ◽  
Identification System ◽  
North West ◽  
The North ◽  
Neighbor Search

This work presents a data-driven approach for the automated risk estimation of the voyage of a vessel or ship. While the industry is moving from a compliance-based framework with existing rules to a risk-based one, there is also a need to monitor the risk of a vessel from the perspective of the navigation. This is of even higher importance for the case of autonomous ships. Built based on the state-of-the-art mathematical representation, the navigation feature, each existing voyage is transformed into a corresponding series of points in [Formula: see text]-dimensional space. During the stage of pre-processing, given a set of historical Automatic Identification System (AIS) data, those records that belong to the same vessel within a certain period of time are taken as a voyage and mapped to the corresponding space of the navigation feature. After the pre-processing and during the online monitoring, the current trajectory of the vessel is transformed into the corresponding representation in the same way. Based on a nearest-neighbor search scheme, the distance from the nearest neighbor is taken as the risk of the current voyage. In other words, the deviation from the closest route in the historical data is taken as the risk. The developed method has demonstrated encouraging performance on a set of challenging historical AIS data from the Australian Maritime Safety Authority, covering three regions in the Australian territory, namely, the Bass Strait, the Great Australian Bight and the North West.

scholarly journals Pregnancy Week-Specific Reference Ranges for Thyrotropin and Free Thyroxine in the North Denmark Region Pregnancy Cohort

Thyroid ◽  
2019 ◽  
Vol 29 (3) ◽  
pp. 430-438 ◽  
Author(s):  
Stine Linding Andersen ◽  
Stig Andersen ◽  
Allan Carlé ◽  
Peter Astrup Christensen ◽  
Aase Handberg ◽  
...  
Keyword(s):  
Free Thyroxine ◽  
Specific Reference ◽  
Reference Ranges ◽  
Pregnancy Cohort ◽  
The North

Standards for measurement and reporting of underwater sound: Application to the source level of trailing suction hopper dredgers.

2011 ◽  
Vol 129 (4) ◽  
pp. 2461-2461
Author(s):  
Christ A. F. de Jong ◽  
Michael A. Ainslie ◽  
Erwin W. Jansen ◽  
Benoit A. J. Quesson
Keyword(s):  
Underwater Sound ◽  
Source Level

Gas Turbine Intake Filter Systems Related to Offshore Platform Installations

1985 ◽  
Author(s):  
M. H. P. Kimm ◽  
D. Langlands
Keyword(s):  
Gas Turbine ◽  
North Sea ◽  
Specific Reference ◽  
Ideal Condition ◽  
Air Filtration ◽  
Contributing Factors ◽  
The North ◽  
Offshore Installations ◽  
Production Platform ◽  
The North Sea

This Paper covers various aspects with respect to the selection and operation of air filtration associated to offshore gas turbine installations. As the Offshore North Sea industry moves into its second decade, Operators are still trying to improve machine availability and reduce maintenance costs. One of the main contributing factors in their failure to achieve the ideal condition has been poor inlet air filtration caused by bad design and incorrect filter selection. The majority of offshore installations are equipped with filter systems which were originally designed for use on ocean-going vessels. The performance of what has become known as the “High Velocity Salt Eliminator System” has, in most cases, been unsatisfactory, thereby creating a necessity for a continuing search into alternative filter systems. The experiences of most Operators in the North Sea have been very similar, and examination of the platform environment explains why this should be the case. To emphasize the affects of poor air filtration and the savings that can be achieved by the Operator in recognising and correcting the problems, specific reference is made to the experience of Mobil North Sea with the Beryl Alpha Production Platform.

scholarly journals Parameter uncertainty of a dynamic multispecies size spectrum model

2016 ◽  
Vol 73 (4) ◽  
pp. 589-597 ◽  
Author(s):  
Michael A. Spence ◽  
Paul G. Blackwell ◽  
Julia L. Blanchard
Keyword(s):  
Time Series ◽  
Time Series Data ◽  
Size Structure ◽  
Management Strategies ◽  
Optimization Methods ◽  
Series Data ◽  
Size Spectrum ◽  
Aquatic Communities ◽  
The North ◽  
Spectrum Model

Dynamic size spectrum models have been recognized as an effective way of describing how size-based interactions can give rise to the size structure of aquatic communities. They are intermediate-complexity ecological models that are solutions to partial differential equations driven by the size-dependent processes of predation, growth, mortality, and reproduction in a community of interacting species and sizes. To be useful for quantitative fisheries management these models need to be developed further in a formal statistical framework. Previous work has used time-averaged data to “calibrate” the model using optimization methods with the disadvantage of losing detailed time-series information. Using a published multispecies size spectrum model parameterized for the North Sea comprising 12 interacting fish species and a background resource, we fit the model to time-series data using a Bayesian framework for the first time. We capture the 1967–2010 period using annual estimates of fishing mortality rates as input to the model and time series of fisheries landings data to fit the model to output. We estimate 38 key parameters representing the carrying capacity of each species and background resource, as well as initial inputs of the dynamical system and errors on the model output. We then forecast the model forward to evaluate how uncertainty propagates through to population- and community-level indicators under alternative management strategies.

Molecular barcoding of north-east Atlantic deep-water sharks: species identification and application to fisheries management and conservation

2008 ◽  
Vol 59 (3) ◽  
pp. 214 ◽  
Author(s):  
Teresa Moura ◽  
Mónica C. Silva ◽  
Ivone Figueiredo ◽  
Ana Neves ◽  
Pablo Durán Muñoz ◽  
...  
Keyword(s):  
Deep Water ◽  
Objective Assessment ◽  
Dna Barcode ◽  
Coi Gene ◽  
Shark Species ◽  
Identification Problems ◽  
East Atlantic ◽  
Molecular Barcoding ◽  
North East ◽  
The North

Two genera of elasmobranchii, Centrophorus and Centroscymnus, include species that represent the highest landings of deep-water sharks caught by fishing fleets operating in the north-east Atlantic. There are morphology-based identification problems among and within genera, and landings of processed shark products further prevent an objective assessment of these species. The present study is the first attempt to test the suitability of using a DNA barcode approach to discriminate accurately among the four most important commercial deep-water shark species: Centrophorus squamosus, Centrophorus granulosus, Centroscymnus coelolepis and, recently discovered in Portuguese ports, Centroscymnus owstoni. Sequence analyses of the mitochondrial DNA cytochrome c oxidase subunit I (COI) gene revealed low levels of haplotypic and genetic diversities. Higher levels of inter-specific relative to intra-specific divergences allowed discrimination among species, which form reciprocally monophyletic clades. Inclusion of published COI sequences from other species within the same genera revealed haplotype sharing among species, which calls into question the current taxonomy and accuracy of fisheries data available. Amplification of the COI gene coupled with MboI restriction digests was found to be a fast and inexpensive strategy to resolve within genera identification problems. Molecular barcoding constitutes a critical tool for the assessment and implementation of urgent management policies for this group of species.

scholarly journals Investigations on Prevalence and Antimicrobial Resistance of Enterohaemorrhagic Escherichia Coli (Ehec) Among Dairy Farms in the North Part of the Republic of Bulgaria

2015 ◽  
Vol 38 (1) ◽  
pp. 21-29 ◽  
Author(s):  
Valentina Urumova ◽  
Mihni Lyutzkanov ◽  
Vladimir Petrov
Keyword(s):  
Dairy Farm ◽  
The Other ◽  
Identification System ◽  
Cattle Farm ◽  
E Coli ◽  
The North ◽  
Enterohaemorrhagic Escherichia Coli ◽  
North Part ◽  
The Republic ◽  
O 157

Abstract Over a 2-year period, from January 2011 to May 2013, a total of 1094 faecal swab samples were collected from cattle at different age at 4 farms in North Bulgaria: Okorsh, Slavyanovo (Popovo municipality), Dobri dol and Trem. Out of them, 36 coli strains (3.3%) positive in the E. coli O:157 antiserum agglutination test and identified by the BBL CRYSTAL identification system as belonging to the E. coli O:157 serotype were isolated. The distribution of isolates was as followed: 5 (0.5%) E. coli O:157 strains at the Okorsh dairy cattle farm, 7 (0.6%) E. coli isolates at the Slavyanovo dairy farm, 16 (1.5%) isolates at the Dobri dol farm and 8 (0.7%) isolates at the Trem farm. Colibacteria exhibited 100% sensitivity to oxyimino-cephalosporins, gentamicin and enrofloxacin, and were resistant to ampicillin (19.4%) and tetracycline (41.6%). From the 15 strains resistant to tetracycline, 11 were isolated from the cows at Dobri dol, while the other 4 originated from the other three farms. The 7 ampicillin-resistant E. coli isolates were detected only at the Dobri dol cattle farm.

Sign in / Sign up

Export Citation Format

Share Document