Volume 8 - 2021 | https://doi.org/10.3389/fmars.2021.609113
This article is part of the Research TopicIsland Dynamical Systems: Atmosphere, Ocean and Biogeochemical ProcessesView all 13 articles
The hydrodynamics and the occurrence of topographic upwelling around the northern Brazilian seamount chain were investigated
Meteorological and physical oceanographic data collected under the REVIZEE-NE Program cruises around the Aracati Bank
the major and highly productive seamount in the area
were analyzed and used to force and validate simulations using the 3D Princeton Ocean Model (3D POM)
The Tropical Water mass in the top 150-m layer and the South Atlantic Central Water (SACW) beneath it and down to a depth of 670 m was present
The thickness of the barrier layer varied seasonally
being thinner (2 m) during the austral spring (October–December) and thicker (20 m) during the austral autumn (April–June) when winds were stronger
The surface mixed and isothermal layers in the austral winter (July–September) were located at depths of 84 and 96 m
those layers were located at depths of 6 and 8 m
The mean wind shear energy was 9.8 × 10–4 m2 s–2
and the energy of the surface gravity wave break was 10.8 × 10–2 m2 s–2
and both served to enhance vertical mixing in the area
A permanent thermocline between the 70- and 150-m depths was present throughout the year
The isohaline distribution followed an isotherm pattern of variation
the formation of low-salinity eddies was verified on the bank slope
The 3D POM model reproduced the thermohaline structure accurately
Temperature and salinity profiles indicated the existence of vertical water displacements over the bank and along the direction of the North Brazil Current
which is the strongest western boundary current crossing the equatorial Atlantic
The kinematic structure observed in the simulations indicated vertical velocities of O (10–3 m.s–1) in the upstream region of the bank during austral winter and summer seasons
the most important vertical velocities were localized below the lower limit of the euphotic zone; while during the austral winter
these velocities were within the euphotic zone
Oceanic islands, seamounts, and banks are associated with propitious fishing grounds worldwide, hosting abundant and diverse biomass and favoring the congregation of marine predators, such as tunas, dolphins, and seabirds (Morato et al., 2008; Pitcher et al., 2008)
These geological features serve as shelter and physical substrates for the development of several species and induce a variety of flow phenomena
Seamounts, characterized as submerged mountains that rise at least 1,000 m above the surrounding seabed, are one of the most common geological features on our planet. Despite their abundance, they have still been poorly sampled and mapped (Wessel et al., 2010; Yesson et al., 2011; Leitner et al., 2020)
The interaction of marine currents with seamounts results in a complex system of circulation, which has been investigated from laboratory and in situ observations (Eiff and Bonneton, 2000; Mourino et al., 2001; Varela et al., 2007; Oliveira et al., 2016), as well as from analytical and numerical modeling studies (Boyer et al., 1987; Morato et al., 2009)
These studies have suggested that the combination of streamline splitting, current intensification, and breaking of internal lee waves plays a significant role as a mixing source in the ocean and may also play a large role in the dissipation of energy from global tides (i.e., Varela et al., 2007; Leitner et al., 2020)
In fact, the circulation patterns modeled and observed suggest that it may be possible that seamounts can increase the amount of chlorophyll in the euphotic zone and that it can be retained locally (White and Mohn, 2004; Lavelle and Mohn, 2010; Watling and Auster, 2017), an effect known in the literature as “SICE–Seamount-Induced Chlorophyll Enhancements” (Leitner et al., 2020)
A very different scenario is verified at the western boundary of the tropical Atlantic, where the presence of deeper and more intense vertical thermohaline gradients prevents the transport of colder central water masses to the ocean surface (de Boyer Montégut et al., 2004; Araujo et al., 2011; Assunção et al., 2020)
The Brazilian islands and seamounts are referenced as an “oasis of life in an oceanic desert,” representing social and economic stakes for the marine national heritage of Brazil (Hazin et al., 1998; Lessa et al., 1999; Chaves et al., 2006; Tchamabi et al., 2017)
Macedo et al. (1998) and Araujo et al. (2018) observed the occurrence of small-scale upwelling regions surrounding the islands and seamounts of Northeast Brazil’s Exclusive Economic Zone (EEZ), and Travassos et al. (1999) indicated that these upwelling phenomena are weak and highly transient
The North Brazilian Chain (NBCh) Banks are very socially and economically important for supporting almost the entire pelagic fishery production of the area (Hazin et al., 1998)
the mechanism responsible for sustaining the high production in this area is not well-known
The aim of this article was to investigate the effects of the flow-topography interaction on the thermohaline structure around the Aracati Bank
analyzing potential locations where an enrichment of the mixed layer may occur
The NBCh Banks (Figures 1A,B) are limited northward by the region where the South American and African continents are closer to each other and southward by subtropical convergence
Figure 1. Study area (A) general location view of the North Chain Banks and major currents at the top 100 m (solid lines) and at 100- to 500-m layers (dashed lines), both compiled from Stramma and England (1999)
(B) Detailed view of the North Chain Banks with bathymetric contours and direction of prevailing winds (dashed arrow)
The NBUC and NBC follow the Brazilian coast and are characterized by a strong northwest acceleration inshore (Richardson and Walsh, 1986; Krelling et al., 2020)
The existence of this structure can be explained because Ekman transport in the western tropical region opposes geostrophic flow, resulting in a typical upwelling situation. Schott et al. (1998) estimated the annual cycle of NBC transport in the oceanic layer between 0- and 500-m depth at coordinates 44° W (0°–5° N) based on the monthly measurement averages from moorings
and the transport speed was 0.54 m.s–1 in summer and 0.75 m.s–1 in winter
In the NBCh area, the southeast trade wind predominates (Figure 1B)
which is the main element of the anticyclonic circulation of the South Atlantic Ocean
These winds can be observed between 35° S up to the equator during the summer (February) and between 30° S up to 10° N during winter (August); these winds are dominant throughout the year in the NBCh area
The Aracati Bank is the larger bank in the NBCh. This bank is 56 km long and 33 km wide and is located in the area where the North Brazilian Current is strongest, exhibiting velocities of 30–50 cm.s–1 during the summer and up to 1 m.s–1 in August (Richardson and McKee, 1984)
The research method involved the analysis of meteorological and physical oceanographic data gathered under the REVIZEE-NE Program around the Aracati oceanic bank and the performance of simulations with the 3D Princeton Ocean Model (POM)
This study was performed using a subset of data gathered under the Project REVIZEE (Living Resources in the Exclusive Economic Zone)
This project was a major national sampling joint effort by the Brazilian oceanographic community and Navy
Expeditions were carried out onboard NOc Antares of the Directorate of Hydrography and Navigation (DHN) of the Brazilian Navy to guarantee country sovereignty over a 200-nautical-mile band as an Exclusive Economic Zone
The efforts along the NE-Brazilian coast section comprised four oceanographic expeditions (REVIZEE NE-I
and NE-IV) corresponding to austral winter
this dataset remains the most complete and robust dataset available for the study area
More recent data for the NBCh Bank area also used here correspond to conductivity
depth (CTD) profiles gathered around the eastern NBCh Banks during the ABRAÇOS II Program and at the Aracati Bank during the CAMADAS FINAS Program in 2017 and 2012
The cruise periods, seasons, and number of CTD casts of those expeditions are summarized in Table 1, and the locations of the oceanographic sample stations, organized according to season, are shown in Figures 2A–F
REVIZEE-NE expeditions organized according to the seasons of the year
Study area with sampling station locations in the North Brazilian Chain (NBCh) during cruises (A) REVIZEE NE-I
We used the data for the sampling stations corresponding to longitudinal and latitudinal transects over the Aracati Bank to investigate the effects caused by the NBC as it encounters this oceanic bank (Figures 2A–D)
wind direction and intensity were recorded using an anemometer
and the wave height and period readings were visually estimated from synoptic satellite data
The thermodynamic dataset for this work comprised CTD continuous profiles taken with a Sea Bird Electronics SBE 911plus CTD with conductivity (resolution = 0.00004 S.m–1)
temperature (resolution = 0.0003°C)
and pressure (resolution = 0.068 m) sensors and a centrifugal pump
CTD operated connected to an SBE 11plus deck unit
We use a fall rate of 1 m.s–1 and a sampling rate of 24 Hz
The maximum sampling depth around the Aracati Bank area was 800 m
Conductivity, temperature, depth archives were transferred to a microcomputer and filtered, reduced, and edited (e.g., removing data out of water and faulty data) in preparation for analysis. Only the readings obtained during the descent of the CTD were considered. The recorded values were integrated at 5-m intervals with the first break, referred to as the surface. The calculations of the physical properties were performed in accordance with TEOS-10 (IOC et al., 2010)
T-S diagrams were then derived for the selected CTD data profiles to allow the identification of water masses present in the area, following the criteria of Barnier et al. (2001), who studied the water masses in the NBC retroflection region as described in Table 2
Table 2. Density range and depth limits of the water mass in the region of the Aracati Bank (Barnier et al., 2001)
where ∂σt/∂T is the coefficient of thermal expansion
Following Sprintall and Tomczak (1992)
we evaluate isothermal and mixed layer depths (ZT and ZM) in terms of temperature and density steps (ΔT and Δσt) from the sea surface temperature and density [T(0) and σt(0)]:
where ∂σt/∂T is calculated as a function of the surface temperature and salinity (Blank, 1999)
whose accuracy is approximately 0.001°C
the error in computing ZT is approximately 0.2% of local ZT
The barrier layer thickness (BLT) may be easily calculated as:
When density stratification is exclusively controlled by temperature
the isothermal layer depth becomes equivalent to the mixed layer depth and BLT=0
A particular situation occurs when the near-surface distribution of salinity is sufficiently strong to induce a pycnocline inside of the isothermal layer
BLT > 0 and surface warm waters may be maintained isolated from cool thermocline waters
These distinct seasonal forcings may be evaluated by calculating the surface TKE input produced by wind shear and gravity wave breaking
Surface TKE production by wind shear may be estimated from the analogy to the near-wall logarithmic region derived from the boundary layer theory (Klebanoff, 1955; Schilchting, 1979)
where an overall balance between the production and dissipation of TKE is observed
This behavior is translated in the following form:
where EW is the wind-driven TKE (m2.s–2), Cμis the diffusivity coefficient (Cμ≅0.09, e.g., Rodi, 1972), and u* is the water friction velocity, which can be estimated from classical drag coefficient formulations (Pond and Pickard, 1983
Zero-order surface wave parameters can be estimated from semiempirical formulations proposed by Stewart (1967) and Leibovich and Radhakrishnan (1977) as follows:
where Ewa is the wave-driven TKE (m2.s–2) and σ is the intrinsic wave frequency (s–1)
6) give the total TKE produced at the ocean surface (ET)
The ocean model used was the POM. It is a three-dimensional ocean model developed by Blumberg and Mellor (1987). A modified version of the POM (Mellor, 1998) is employed to solve the primitive equations within a closed domain. This model uses curvilinear orthogonal horizontal coordinates, a horizontal numerical staggered “C” grid (Arakawa and Lamb, 1977)
and employs a terrain-following σ-coordinate system in the vertical direction
making it well suited for the resolution of the bottom boundary layer
The numerical study area includes a rectangular domain with four open boundaries with the Aracati Bank near the southeastern boundary. The bottom topography was defined using a nautical chart # 700 (Diretoria de Hidrografia e Navegação [DHN], 1974)
The horizontal model grid includes 41 × 61 grid cells with a constant grid size of Δx = Δy = 2 km
The vertical grid includes 21 σ-layers exponentially distributed at the surface and bottom to obtain better results in the vertical layer due to the formation of important pressure gradients around and over the bank (Tchamabi et al., 2017)
All experimental data and the temperature and salinity profiles were associated with the bank shape from REVIZEE-NE cruises and used in the simulation conditions
Two seasons were considered for simulation: the austral winter season (March–August) and the austral summer season (September–February)
In a preliminary analysis of the thermodynamic properties in the study area
the simulation was enabled to verify that the information relative to the rainy season (austral autumn and winter) could be grouped into a single scenario
it was possible to group the data of the austral spring and summer periods for the numerical representation of the dry scenario
Boundary conditions considered in simulations according to the seasons of the year
The analysis and treatment of in situ data allowed the identification of two main water masses in the Aracati Bank area (Table 4)
Characteristics of the water masses identified in the Aracati Bank area
Figures 3A–F presents the T/S diagram obtained from the field CTD profiles. The red ellipses in Figures 3A,C indicate major dispersion of the thermodynamic data near the interface between the Tropical Water and the South Atlantic Central Water masses (TW–SACW). These dispersed cloud points correspond to oceanographic data obtained from the sample stations located in the upstream region of the Aracati Bank (Geber, 2001)
suggesting that it may be associated with the “deformations” in the TW–SACW interface
Figure 3. Seasonal variability in T/S diagrams in the Aracati Bank area during cruises (A) REVIZEE NE-I, winter; (B) REVIZEE NE-II, summer; (C) REVIZEENE-III, autumn; (D) REVIZEE NE-IV, spring; (E) ABRA OS II, autumn; and (F) CAMADAS FINAS III, spring. Blue dots are T and S field CTD data for upstream region of the Aracati Bank (Geber, 2001)
The red ellipses indicate the dispersion of the termodynamical characteristics of the waters near the interface between the Tropical Water and the South Atlantic Central Water masses (TW-SACW)
Eqs. (1–3) are used in this work to evaluate the seasonal variability of the isothermal (ZT), mixed (ZM), and BLTs in the study area. Figure 4 presents the seasonally averaged values calculated from the CTD profiles
and BLT during autumn and winter and the presence of considerably shallower layers during summer and (mainly) austral spring
the isothermal layer (ZT) was limited to 8 m during spring and reached a most important value of 96 m during winter
The resulting BLT values indicated the presence of significant BL during autumn (20 m thick)
contributing to isolating surface warmer waters from deeper and colder nutrient-rich waters
negligible values of BLT are found during summer and (mainly) spring seasons
These periods of the year are characterized by the action of less intense winds and lower precipitation rates
while stronger surface forcings (wind and waves) observed during autumn and winter contribute to sinking the isothermal and mixed layers in the Aracati Bank area
Seasonal variation of the average isothermal
and barrier layer thickness in the Aracati Bank area
This result suggests that gravity waves are the prime candidate for driving the erosion/deepening of seasonal pycnoclines in the study area
If one chooses wind shear energy (EW) and wave number (k) as normalization scales, it is possible to establish a linear ratio between the total TKE (ET = EW + EWA) and its capacity for mixing the upper surface layers (ZM). This relationship is represented in Figure 5
It was determined using the least-squares curve fitting method for wind speeds between 6.2 and 13.4 m.s–1 (87% of overall field data) as follows:
Values of surface energy and mixing layer depth in the Aracati Bank area (blue dots) and adjusted linear regression (red line)
Linear ratio between the total TKE (ET = EW + EWA) and its capacity for mixing the upper surface layers (ZM)
where small hats represent non-dimensional variables
A simple scale analysis involving energy and wind/wave parameters may also be performed to show that the mixing layer depth is proportional to the wave height in the following form:
Expression (9) also states that the upper mixed layer depth is proportional to the square of the wind speed. Wind speeds registered during autumn–winter in the Aracati Bank region are approximately 50% higher than the measured values for spring–summer periods (Geber, 2001). These differences may then explain the seasonal evolution of mixed layer depths previously stressed from field data (Figure 4)
the time step for numerical stability in the winter for the 15th day was an average global energy of 9.7 × 103 J
the energy stabilized for the 10th day with an average of 7.8 × 103 J
as well as the time step needed for model “spin-up.” For both winter and summer scenarios
only numerical results corresponding to the numerical time 21st day were considered
despite the fact that the model stability was being achieved before this delay
The numerical T/S profiles were systematically compared with experimental data. Figure 6 gives some typical examples of the parallel between temperature and salinity profiles issued from numerical simulations and T/S distributions obtained from a field CTD device
The comparison of T/S profiles shows that the model is able to generate profiles correctly
even the maximum salinity at the surface that was observed in the field
This result also suggests that the model supplies good descriptions of the thermohaline structure observed from field measurements
Comparison between experimental data and numerical simulation results for temperature and salinity profiles in the winter (A,B) and summer (C,D) seasons
To analyze the horizontal circulation in the area of Aracati Bank, horizontal velocity fields were traced at depths of 50, 100, 250, 500, and 1,000 m. Figures 7A–J show the numerical velocity fields generated by the model for the winter and summer seasons
Horizontal velocity (m.s– 1) fields in the Aracati Bank area at depths of 50
and 1,000 m during winter (A–E) and summer (F–J) seasons
Figures 7A–J show that the velocity vectors turn around the bank
where the horizontal velocity gradients between the bank and the frontal slope are stronger
However, in the summer season (Figures 7F–J), changes in current vector directions in the upstream bank area are less pronounced relative to winter simulations (Figures 7A–E)
Eddies made by horizontal velocities could “arrest” nutrients
and larvae that are important for increasing marine productivity
To analyze the Aracati Bank potential in producing eddies in its vicinity
the vertical component of the vorticity in the bank area was calculated as follows:
where Ω→ is the relative vertical vorticity (s–1)
Vertical vorticity (s– 1) in the Aracati Bank area at depths of 50
Figure 9 presents the temperature and vertical velocity (w) profiles obtained from simulations for both winter (Figure 9A) and summer (Figure 9B) seasons across the Aracati Bank section along the NBC
the NBC crosses the bank from right to left
Temperature and w vertical velocity along a section crossing the Aracati Bank area during winter (A) and summer (B) seasons
North Brazil Current (NBC) crosses the bank from the right to the left side
As a result of the flow-topography interaction
upstream isotherm perturbation and upwelling and downstream leeward and eddy generation were verified during both seasons
The highest intensities in vertical velocity (Figures 9A,B) are located in the upstream bank region and tend to decrease toward the surface
The minor vertical velocity during the winter was 0.003 × 10–3 m.s–1 near the surface
and the major value was 8.4 × 10–3 m.s–1 at a 370 depth
with an average velocity of 2.2 × 10–3 m.s–1
these values were 0.0004 × 10–3 m.s–1 (near the surface) and 7.8 × 10–3 m.s–1 at a 266-m depth
with an average of 2.6 × 10–3 m.s–1
these shallower maximum vertical currents result in a more pronounced near-surface isothermal perturbation
cross-bank circulations exhibit a strong asymmetry with respect to the two sides of the bank
they observed that when the side of the bank was much steeper
and the vertical mixing increased by approximately 0.1 × 10–3 m.s–1 at a depth of 120 m
The temperature CTD profiles indicated the presence of a permanent thermocline throughout the year
The pattern of isohaline distribution followed that of isotherm variation
the formation of low-salinity eddies was verified on the Aracati Bank slope
The 3D model used was able to accurately reproduce the thermohaline structure in the Aracati Bank area
The kinematic structure observed in the performed simulations indicated vertical velocities of 10–3 m.s–1 in the upstream region of the bank during winter and summer seasons
the most important vertical velocities were localized below the lower limit of the euphotic zone
The data recorded for the Aracati Bank provided clear evidence that upwelling and consequent enrichment of the surface layer can result from a flow-topography interaction in this area, especially during the winter season. Similar uplift of isotherms was observed in October 1990 during fishing surveys near the Aracati, Guará, and Sírius seamounts (Hazin et al., 1990)
reinforcing the notion that this process could occur in fairly regular basis and that they are linked in some way to the Aracati Bank topography and NBC interaction
The strong physical forcing by the NBC and southeast trade winds over the Aracati Bank contributes significantly to possible rises in thermodynamic parameters in the study region
While the results presented here provide evidence to show that the interaction between Aracati Bank and the NBC promotes vertical mixing
the observations are limited to the relatively small spatial and temporal scales examined
Further research is still required to determine the influences of the thermodynamic parameters and analysis of complementary chemical and biological variables across different spatial and temporal scales
The raw data supporting the conclusions of this article will be made available by the authors
All authors listed have made a substantial
direct and intellectual contribution to the work
MA and CN acknowledge the support of the Brazilian Research Network on Global Climate Change-Rede CLIMA (FINEP grants 01.13.0353-00)
This work is a contribution to the Projects INCT AmbTropic–Brazilian National Institute of Science and Technology for Tropical Marine Environments (grants 565054/2010-4
International Joint Laboratory TAPIOCA (IRD-UFPE-UFRPE)
which has received funding from the European Union’s Horizon 2020 Research and Innovation Program under grant agreement no
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest
We thank the scientific and crew members of the NOc Antares/Brazilian Navy for their efforts during the oceanographic expedition
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Noriega C and Costa da Silva A (2021) Ocean Dynamics and Topographic Upwelling Around the Aracati Seamount - North Brazilian Chain From in situ Observations and Modeling Results
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which takes place every month in the neighborhood
brings together the best of Eastern European cuisine and handicrafts
Once a month – always on Sundays – the Eastern European Cultural Fair takes place in Vila Zelina
a region known as the “eastern European city of São Paulo”
The fair takes place from February to December
with the arrival of Santa Claus and gift options
The event features different cultural attractions and workshops every month
It’s the perfect place to see the handicrafts and enjoy the cuisine of countries such as Ukraine
the stalls offer typical food from the various Slavic peoples
The region’s traditional handicrafts include Russian “matrioshkas”
📍 Rua Aracati Mirim – Vila Prudente
Metrics details
Multibeam forward-looking sonar (MFLS) plays an important role in underwater detection
There are several challenges to the research on underwater object detection with MFLS
generally processed at pixel level and transformed to sector representation for the visual habits of human beings
is disadvantageous to the research in artificial intelligence (AI) areas
the underwater acoustic target detection (UATD) dataset
consisting of over 9000 MFLS images captured using Tritech Gemini 1200ik sonar
Our dataset provides raw data of sonar images with annotation of 10 categories of target objects (cube
The data was collected from lake and shallow water
we apply the dataset to the state-of-the-art detectors and provide corresponding benchmarks for its accuracy and efficiency
semantic segmentation and other AI applications
Due to the scattering and attenuation of the light in water
underwater optical imaging is a difficult task and often gets low quality images
So acoustic sensors are widely used for perceiving the underwater environment
MFLS is portable for underwater robots while providing dynamic real-time image data in high resolution
It is very applicable for scenarios requiring close and detailed inspection
There are different defects among the datasets used in these researches
and virtual image data based on style transfer technology
The most important point is that most of the datasets in the related research are not public
Since the complexity of acoustic propagation property and the instability of underwater environment
there have always been differences between the generated images and real images
the lack of dataset obstructs the development of research on object detection with MFLS images in AI areas
Our proposed dataset aims to improve the above situations
The Gemini software development kit providing the raw data of sonar images is available for Windows and Linux operating systems
Environment and satellite map of experiments performed
The scale of the objects is shown below the name of the objects in the figure
The scale is in meter and the representation: L(Length)
we drove the boat mounted with sonar and cruised around the selected sites
searching the target objects and recording data by adjusting the sonar direction
This example shows the moving ROV during the data collection
The dataset contains 9200 image files in BMP format corresponding with the same number of annotation files in XML format
“UATD-Training” contains 7600 pairs of images and annotations
The remaining two parts contain 800 pairs of images and annotations respectively
storing the image files and annotation files respectively
The image files are in the folder named “image”
and the annotation files are in the folder named “annotation”
An overview of the distribution statistics of UATD dataset
The appearances of the same underwater target object at different imaging angles of the MFLS are generally different
leading to a great challenge to the subsequent labeling work
we designed three effective methods to ensure the accuracy of sonar image annotations
three members of our team were responsible for the annotation and completed the labeling work individually after randomly assigning the collected data
with the data playback function in OpenSLT
cross-checking was performed to reduce manual annotation errors
we recorded the video stream displaying the processed images for vision habits from Gemini 1200ik synchronously with raw data during the data collection
OpenSLT played back the data in the way of the stream to corresponding with the recorded video stream
So it was convenient to detect and track the object by comparing it with the video during annotating the raw data in OpenSLT
avoiding labeling errors caused by losing the target
we handed over the annotated data to a professional data management company cooperating with us
The professional staff members of the company have checked the data again to ensure correctness
the efficiency was tested on the local computer and the indicators of FPS
mAP - Corresponds to the mean AP for intersect of union (IoU) equals to 0.5 on total categories (10 in UATD)
mAR - Corresponds to the mean recall rate on total categories (10 in UATD)
APname - AP of class (name belongs to the classes in UATD)
FLOPs - Floating-point operations per second with input image size of 512 × 512
the initial learning rate was set to 0.0005 and decreased by 0.1 at the 8th and 11th epoch (12 epochs in total) respectively
The warm-up strategy was adopted with a 0.0001 warm-up ratio and increased by linear step in the first 500 iterations
Adam method was employed to optimize the models
Faster-RCNN with Resnet-18 backbone achieves the best mAP of 83.9% and the best mAR of 89.7%
YOLOv3 with MobilenetV2 backbone has a good performance in efficiency with only 3.68 M Params and 4.22 G FLOPs
as well as the fastest inference speed of 93.4 FPS tested on the local machine
UATD dataset is published in a figshare repository19
the annotation tool OpenSLT is published alongside the dataset
The tool worked well on Ubuntu 18.04/20.04 environment during our annotation work
we provide an example (a small dataset with several sonar image files and corresponding CSV files) with the tool for users to test
The file README.md along with the tool plays the role of guidance for the users
Islam, M. J. et al. Semantic segmentation of underwater imagery: Dataset and benchmark. In 2020 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 1769–1776, https://doi.org/10.1109/IROS45743.2020.9340821 (2020)
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Sung, M. et al. Realistic sonar image simulation using deep learning for underwater object detection. International Journal of Control, Automation and Systems 18, 523–534, https://doi.org/10.1007/s12555-019-0691-3 (2020)
Liu, D. et al. Cyclegan-based realistic image dataset generation for forward-looking sonar. Advanced Robotics 35, 242–254, https://doi.org/10.1080/01691864.2021.1873845 (2021)
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This work was supported by the National Natural Science Foundation of China (Grant, No.62027826). We thank the Dalian Key Laboratory of Underwater Robot of Dalian University of Technology for their support during the data collection. We thank the support provided by OpenI Community(https://openi.pcl.ac.cn) during data processing
These authors contributed equally: Kaibing Xie
Jian Yang and Kaibing Xie generated the dataset
Jian Yang contributed to the annotation software development and technical validation
Kaibing Xie draft the paper and provided feedback on the manuscript
The authors declare no competing interests
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations
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the scheme seeks to restore the cultural values of a historically marginalized population
all images courtesy of bernardo horta arquiteto
the buildings are raised; recycled and concrete-filled tires serve as foundations
this construction system allows different materials to be applied to the primary structure
bringing local techniques to a contemporary process and meaning the proposed buildings can be adapted to their context
flexibility in the use of components (doors
roof and objects) and in the grouping of modules
allows the housing system to be improved whenever new partnerships are created between owners
traditional construction and regional wooden handicrafts and fabrics are restored in various ways
the walls in the longitudinal direction of the buildings follow the traditional method of pau-a-pique (a mixture of clay
the front and rear elevations can be varied (using muxarabi
or fabric) according to the user’s needs
these materials can create an interesting play of light and shadow that establishes an interior and exterior relationship through controlled permeability
the modules includes large semi-outdoor areas
another important concept for the project is to encourage community living
the idea of an open architecture allows for various appropriations of public and semi-public space
guaranteeing socializing between residents and increasing neighborhood ties through the large porch areas
architect: bernardo horta arquiteto
designboom has received this project from our ‘DIY submissions‘ feature, where we welcome our readers to submit their own work for publication. see more project submissions from our readers here.
happening now! partnering with antonio citterio, AXOR presents three bathroom concepts that are not merely places of function, but destinations in themselves — sanctuaries of style, context, and personal expression.
For years now, Brazilian singer-songwriter and drag queen Pabllo Vittar has engaged in such celebrations in her native country—but she says this year’s Carnaval was especially meaningful. “It is my favorite time of year, and I missed it for the past two years,” says Vittar. “Carnaval is a moment that you can shine even more! The outfits, the energy, the party; The feeling is unlike anything I have ever experienced in the world yet.”
Vittar certainly had lots of parties to partake in during her busy Carnaval last week. The pop star was booked and busy, playing 8 shows in 5 different cities. “Carnaval is important all over Brazil, and is an amazing time for the whole country to come out to celebrate in every town,” says Vittar. “It was crazy—a lot of work, but a lot of fun.”
Below, see Vittar’s 6 epic Carnaval costumes—and the inspiration behind them, too.
It was intended to bring back the childhood nostalgia that many of us have when remembering Toy Story. I think it's a fantasy that many generations remember when they see good things and it's the feeling we look for in Carnival. It's a happy and fun fantasy!
Before going to school, I watched X-Men: Evolution. I love Rogue and her youthful complexities in this cartoon. That's why I brought her into this story of characters that I wanted to show at Carnival.
In the Naruto saga, one of the powers that most caught my attention is the Sexy Jutsu. It is a technique that the ninja applies to win many battles. He transforms into a woman and bewitches his opponents to win. And, people always remembered me in this transformation. I think that's why fantasy is so successful.
It is one of my favorite animes from my childhood; It is to remember the dreams I had back then. Reliving it was amazing!
I think everyone knows I'm a gaming addict. And, one of the games I love the most is Mortal Kombat, and the character I play the most as is Kitana!
I love horror and I love M3GAN. When I saw the dance she does, I knew right away that we had to have her in the story of Carnaval. And, I think we are very similar physically!
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Brazil’s Omega Energia’s new 4.6 GW solar project is set to become the world’s largest PV installation upon completion
the Brazilian state of Ceará has postponed plans to grant it an environmental license until Dec
Brazil-based Omega Energia is now developing what is set to become the world’s largest solar project
It has yet to reveal its investment in the 4.6 GW Kuara solar park
which will feature 8 million solar modules from an undisclosed manufacturer
The project will cover 7.8 thousand hectares of unused farmland between the municipalities of Aracati e Icapuí
The environmental council of Ceará met this week to discuss the project's environment license
and decided to postpone its final decision until Dec
It noted that a member of the Order of Attorneys of Brazil has asked to visit the project site before casting a vote
Omega Energia will sell some of the electricity to Australian iron ore producer Fortescue
The company plans to build an industrial green hydrogen plant in the port of Pecém
More articles from Beatriz Santos
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