Underwater Research Papers - Academia.edu (original) (raw)

In this paper, we propose an orthogonal frequency division multiplexing (OFDM) based underwater acoustic multimedia system. An essential feature of this system is that it offers larger power and schemes providing significant error protection for the transmission sensor data information that requires higher quality of service (QoS). To realize maximum resource utilization, or minimum total transmission power, we also include an adaptive modulation strategy into the system. Thus, in the proposed underwater acoustic multimedia system, high power, low speed modulation, and scheme providing significant error protection schemes are employed for the transmission of sensor data messages that require a stringent bit-error rate (BER). In contrast, low power, high speed modulation, and less capable error protection schemes are provided for messages that can tolerate a high BER. A simulation is carried out to verify the proper functioning of the proposed system in a practical underwater acoustic multimedia scenario.

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- Multimedia, OFDM, Underwater, QoS
- by Marti Anderson
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- Marine Biology, Biological Sciences, Environmental Sciences, Underwater

network classifiers have been widely used in classification due to its adaptive and parallel processing ability. This paper concerns classification of underwater passive sonar signals radiated by ships using neural networks. Classification process can be divided into two stages: one is the signa preprocessing and feature extraction, the other is the recognition process. In the preprocessing and feature extraction stage, the wavelet transform (WT) is used to extract tonal features from the average power spectral density (APSD) of the input data. In the classification stage, two kinds of neural network classifiers are used to evaluate the classification results, inclusive of the hyperplanebased classifier-Multilayer Perceptron (MLP)-and the kernel-based classifier-Adaptive Kernel Classifier (AKC). The experimental results obtained from MLP with different configurations and algorithms show that the bipolar continuous function possesses a wider range and a higher value of the learning rate than the unipolar continuous function. Besides, AKC with fixed radius (modified AKC) sometimes gives better performance than AKC, but the former takes more training time in selecting the width of the receptive field. More important, networks trained with tonal features extracted by WT has 96% or 94% correction rate, but the training with original APSDs only have 80% correction rate. &words-Underwater signal classification, Neural networks, Wavelet transform, Multilayer perceptron, Adaptive kernel classifier.

- by Ozhan Duzenli
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- Applied Mathematics, Parallel Processing, Neural Network, Underwater

: China is strengthening diplomatic ties and building naval bases along the sea lanes from the Middle East. This "String of Pearls" strategy is designed to protect its energy security, negate US influence in the region, and project power overseas. China is rapidly building a blue-water navy, developing advanced missile technology, and stockpiling undersea mines to counter US Navy capabilities, especially in the event of a conflict over Taiwan. To counter China's growing naval power, the United States can exploit a critical vulnerability China's dependence on sea lines of communication. Eighty percent of China's oil imports pass through the Strait of Malacca; the Chinese leadership calls this strategic weakness the "Malacca Dilemma." In conjunction with naval forces, land-based airpower offers a promising way to control key maritime checkpoints and trade routes. Land-based airpower proved a decisive maritime force in the war against Japanese shipping d...

- by Lawrence Spinetta
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- Engineering, Military History, Leadership, China

AREA 4 WORK UlNIT NUMNERS S Espey, Huston and Associates P.O. Box 519 Austin. Texas 78767 11. CONTROLLING OFFICE NAME AND ADDRESS 12. U.S. Army Corps of Engineers-Mobile Dist.Ka b , lC4 P.O. Box 22C8 1 NUMBER Of PAGES l'obile, Alabama 36621 11 4 MONITORING AGENCY NAME S ADORESSII dtfloeat Iroow Controlling Office) 15 SECURITY CLASS (.t [hit report, Un clas sif ie d 158. DECL ASS FiCATiONDowoNGRADiGr SCHEDULE Unclassified IS DISTRIBUTION STATEMENT (of 9tel. Reprt) DmFTROUION STATEMEN A UlmtdE E T Appoved i public releo~sq 1 nimte Distnbution UnlimitedDE17 4 IS. SUPPLEMENTARY NOTES IS KEY WORDS (Continue an reverse side if necessary and Identify by block number) magnetic anomalies, underwater archaeology, harbor defenses, >_ Civil War history, Confederate Corps of Engineers, remote sensing LU 0 Ae A rRACT (Gawtlnwisoes av .I N nceam ost idm,1ily by block niibot) DD~ j)oR3 473 EritION or , mov es is OBsoLeTE SECU*ITY CLASSIFICATION OF THIS PA4GE (Ilben Dote Ent.eod) Block 20 cont'd. The archaeological and historical data developed during this study demonstrate that a section of the Confederate harbor obstructions of Mobile runs diagonally through a proposed Turning Basin. These obstructions consist, in part, of vessels which were loaded with brick and sunk across the old channel in the period 1i62-1864. An investigated anomaly identified as TB-4-3 is believed to represent one of these vessels. A mitigation plan for TB-4-3, the "brick obstruction", as well as suggestions for further lines of research along the rest of the line, are presented to the Corps of Engineers, "lobile District, for future planning of the Mobile Bay Project.

- by Jack Irion
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- Underwater, Channels, Brick, Archeology

A dichotomy between depth penetration and resolution as a function of sonar frequency, draw resolution, and beam spread challenges fish target classification from sonar. Moving high-frequency sources to depth using autonomous underwater vehicles (AUVs) mitigates this and also co-locates transducers with other AUV-mounted short-range sensors to allow a holistic approach to ecological surveys. This widely available tool with a pedigree for bottom mapping is not commonly applied to fish reconnaissance and requires the development of an interpretation of pelagic reflective features, revisitation of count methods, image-processing rather than wave-form recognition for automation, and an understanding of bias. In a series of AUV mission test cases, side-scan sonar (600 and 900 kHz) returns often resolved individual school members, spacing, size, behavior, and (infrequently) species from anatomical features and could be intuitively classified by ecologists — but also produced artifacts. Fi...

- by Thomas Grothues
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- Zoology, Computer Science, Ecology, Sonar
- by bill verplank
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- Models, Underwater, Mathematical Models, Computer Control

Clean water supply is important in ensuring good health of people. Water supply is distributed from water storage tanks. Sediment that accumulates over time in water storage tanks will deteriorate the water quality used by consumers. Therefore, water storage tanks are required to be cleaned once in every three years by water utility operators or tank cleaning service providers. Manual cleaning method is done by draining off and resupply water into the tank after workers have cleaned the tank using water jet and brushes. In this paper, an alternative cleaning method using a Remotely Operated Underwater Vehicle (ROV) is proposed. Using ROV, water supply disruption can be prevented and cleaning process will be more efficient and cost effective. An ROV is built to operate underwater and vacuum out sediments from water tank. Operator on screen can see live-streaming video. Raspberry Pi is used as the main communication board to interface with MATLAB. Operator will operates the ROV remotely to carry out the cleaning process. IMU sensor was also used for simulation study in MATLAB for orientation movements testing.

- by ahmad 'athif mohd faudzi and +2
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- ROV, Underwater

These underwater radiated noise and vibration measurements were conducted on a full-scale ship in August 2000. During the trails it was found that several spike noises are dominant. To find the location oj high vibration level places and its frequencies, and the machines, which generated high level point noise components, 4 accelerometers were fixed in the engine and auxiliary rooms .We were using this system to find the relationship between certain manoeuvres and the vibratlon level caused by them. Propellers and engines are usually the major sources of noise in ships but gearboxes can also be significant contributors. The way of mounting of the machines and the resulting vibration oj the hull are determining issues in the radiation ot underwater noise. Naval Test and Evaluation Acoustic Ranges contain an accurate radiated noise measurement system consisting of a bottom-mounted hydrophone array for sailing condition and a stationary range. The sophisticated digital narrow-band inst...

- by Vladlena Voloshyna
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- Marine Engineering, Propulsion, Propeller, Underwater

With recent advances in battery capacity and the development of hydrogen fuel cells, autonomous underwater vehicles (AUVs) are being used to undertake longer missions that were previously performed by manned or tethered vehicles. As a result, more advanced navigation systems are needed to maintain an accurate position over a larger operational area. The accuracy of the navigation system is critical to the quality of the data collected during survey missions and the recovery of the AUV. Many different methods for navigation in different underwater environments have been proposed in the literature. In this paper, the state of the art in navigation technologies for AUVs is investigated for theoretical and operational systems. Their suitability for use in different environments is compared and current limitations of these methods are identified. In addition, new approaches to address these current problems and areas for future research are suggested. Finally, it is concluded that only geophysically referenced methods will enable AUVs to navigate accurately over large areas and that advances in underwater feature recognition are required before these methods can be implemented in operational AUVs.

- by Honghai Liu
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- Engineering, Pattern Recognition, Computing, Fuel Cell

Biofilm effects on corrosion………………………………………………………… 3.4.3 Silica…………………………………………………………………………………. 3.4.4 Temperature ………………………………………………………………………….. 3.4.5 PH……………………………………………………………………………………… 3.4.6 Salinity……………………………………………………………………………….. 3.4.7 Alkalinity of seawater…………………………………………………………………. 3.4.8 Dissolved oxygen……………………………………………………………………… 3.5 Corrosion products of iron (Decay products)…………………………………………… 3.6 Post-excavation changes in iron antiquities (Wet artifacts)…………………………… … 3.7 Iron artifacts after drying out…………………………………………………………… Chapter 4: Difference methods of dechlorination of excavated iron artefcats from the seawater…………………………………………………………………………………….

- by Saleh Ahmed
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- Archaeology, Corrosion, Underwater

This report documents a study performed for the U.S. Army Engineer District, Seattle to identify and evaluate feasible methods for reducing annual maintenance dredging in the outer Federal navigation channel at Grays Harbor, WA, by modification of the north jetty. Main interest was in potential reduction of southward sand bypassing the north jetty and preservation of the jetty should the neighboring beach erode. Considerable information and predictive capability were generated concerning the behavior of the Federal navigation channel and adjacent coastal and inlet shorelines. The study was conducted as a coordinated multi-disciplinary approach involving field measurement, physical modeling of the hydrodynamics and potential sediment pathways, geomorphic analysis and sediment budget formulation, and numerical modeling of waves, circulation and sediment transport, including modeling of shoreline change and bypassing. Numerous alternatives were considered and subjected to a screening p...

- by Mary Cialone
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- Geomorphology, Navigation, Underwater, Sediment transport

Large-scale spatial surveys of fish species in relation to habitat have tended to focus on depth, sediment type and temperature as descriptors of fish habitats. At a smaller scale, habitat parameters such as the relief of the sea floor, the presence of structuring fauna and prey availability may have a considerable influence on fish distribution, but often are not considered. In the present study we used video survey techniques to study habitat components in areas of the English Channel that were known to support consistently high densities of adult plaice. Habitat features were quantified and related to the density of adult plaice caught within the same study areas. To focus the study on habitat components other than sediment type all sites chosen had sandy substrata. The scale and spatial distribution and heterogeneity of physical and biological structures were quantified for each site and correlated to plaice densities. Plaice densities correlated with the abundance of benthic fauna recorded. In particular the emergent tube-dwelling polychaetes Lanice conchilega and Cheatopterus spp., which are a valuable food source for plaice, dominated some sites. Abiotic habitat features and habitat heterogeneity showed no clear relationships with respect to plaice densities at the scale of our surveys. This indicated that prey availability might be the driving force for habitat selection of adult plaice within sandy habitats and that other habitat descriptors assume less importance at smaller spatial scales.

- by Michel Kaiser
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- Oceanography, Heterogeneity, Underwater, Habitat

Research on motion analysis of swimmers is commonly based on video recordings of the subject's motion, which are analyzed by manual digitization of feature points by an operator.

- by Zimi Sawacha
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- Biomechanics, Underwater, Automatic

As an acoustic communications medium, water is characterized by frequency dependent attenuation, short range, very low bandwidth, scattering, and multi-path. It is generally difficult to acoustically communicate even terse messages underwater much less images. For the naval mine countermeasures mission, there is value in transmitting images, if possible. The contribution of this paper is a methodology to encode, compress and transmit small (100s of kB) side-scan sonar images underwater with micromodems. The work has been validated through several at-sea trials. The reconstruction of the received images is of a fidelity that operators can visually recognize targets they normally look for in these images. Keywordsunderwater communications, transmission of sonar images underwater, image compression, image encoding

- by Mae Seto
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- Computer Science, Acoustics, Underwater, Underwater Acoustic Communication

- by Carl Tiltman
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- Engineering, Pattern Recognition, Computing, Fuel Cell

Under Water Vehicles (UWVs) are extensively being used for variety of operations. Recently, there has been an increased interest in the design of autonomous unmanned underwater vehicles design (UUVs) as future generation submarines. The aim of this study is to investigate the effect of the various design parameters on the rotary coefficients of one such UWV i.e. a submarine SUBOFF model. The rotary coefficient has been calculated using the numerical simulations. The effect the wall roughness, linear velocity, rotation speed has been studied using the steady state Reynolds Averaged Navier-Stokes (RANS) simulations. The study helps to understand the underlying hydrodynamic phenomenon showing the dependence of these parameters on the hydrodynamics of the underwater vehicles.

The variety, availability, sales and use of dietary supplements (DS) remain poorly understood by the mainstream medical community, but the potential for use and abuse of DS cannot be taken lightly by undersea medical officers (UMO). Despite the indisputable pharmacologic effects many of these over-the-counter (OTC) products exert, the use of DS is generally overlooked by clinicians. DS information is not covered in much depth, if at all, in medical education, and physicians are not trained in this area. As such, many may feel uncomfortable with their lack of familiarity regarding the ever-increasing supplement pharmacopoeia. Peer-reviewed scientific research and evidenced-based information are often limited. Moreover, because the general public and active duty community perceive these natural substances as harmless, the products often do not come to the attention of physicians at all. Less than half of all users of DS consult a physician or a practitioner about alternative products ...

- by Vincent Moore
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- Attention, Medicine, Underwater, Physicians

A literature, archival, and historic review was conducted to determine the potential for submerged cultural resources within portions of the lower Pascagoula and Escatawpa Rivers, Jackson County, Mississippi prior to navigation improvements by the U.S. Army Corps of Engineers, Mobile District. The research included a review of primary and secondary literature, cartographic and newspaper archives, as well as local informant interviews. The review concluded that there is little potential for adverse impact to submerged cultural resources within the current navigation channel, however, channel realignment holds the potential for adverse impact to vessels related to Pascagoula/Moss Point's late nineteenth to early twentieth century timber industry.

- by Catherine Clinton
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- Geography, Navigation, Underwater, Resources
- by Ilse Van Opzeeland
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- Acoustics, Animal Behavior, Fisheries, Sound

Portable underwater electrical power is needed for many commercial, recreational and military applications. A battery system is currently not available to meet these needs, which was the aim of this project. Lithium-ion battery cells (Panasonic (CGR18650E)) were chosen, based on their high energy density and availability. To increase their voltage, 8 battery cells were connected in series (“sticks”) and protected

- by David Pendergast
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- Engineering, High Energy Density Physics, Underwater, Lithium Ion Battery

To examine the attractiveness of coloured fish aggregation devices (FADS), six sets of four to six FADS of the kite type were deployed in coastal waters and dive observations were carried out for 15 months. The FADS had the same dimensions but different kite colours: white, black, blue, green, yellow and red. Fish abundance and aggregation patterns around the FADS were scored and statistically analysed. Fish tended to be most abundant near the blue and green FADS, least abundant near the black and white FADS, and intermediate. near the yellow and red FADS. Aggregations stayed closer to green and blue FADS than to white, yellow, black or red FADS. The more attractive FADS were the less visible ones. Thus, fish were attracted to blue and green FADS on the basis of hue rather than contrast.

- by Gunzo Kawamura
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- Fisheries, Ecology, Color, Underwater

The rapid biofouling of fish-cage netting in Tasmania, Australia, necessitates the frequent changing of nets for onshore cleaning. To reduce the cost associated with this capital-and labour-intensive process, a prototype underwater net cleaner was designed and constructed for the Tasmanian Atlantic salmon industry. This study describes trials aimed to determine the efficacy of this prototype, and to identify areas for improvement. The reduction in open area of netting mesh due to fouling growth, together with subsequent increases in open area after cleaning, were monitored by image analysis of underwater photographs. The preferential removal of larger fouling species and the occurrence of resistant species were documented. The design of the cleaning head and displacement of netting away from the cleaner reduced the severity of scrubbing, limiting fouling removal. However, with increased contact between the brushes and netting the cleaner prevented significant fouling development over a lo-week period. Scanning electron microscopy was used to identify the extent of residual fouling after cleaning, and the difficulty of removing fouling from crevices in the netting surface and from the sides of netting bars. The system can be highly effective, but the current design for presentation of the brushes greatly limits cleaning efficacy. The research has identified areas for design improvement, the

- by Chris Burke
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- Zoology, Biology, Image Analysis, Scanning Electron Microscopy

This study presents the first observations of Hucho taimen spawning in the wild based on underwater video recordings. One pair of taimen was monitored during a 19 h period, supplemented with visual observations from two other spawning pairs. We recorded two full spawning events performed in two different locations separated by approximately 30 m. The absence of an established male hierarchy along a nesting female was the most important difference between taimen and other salmonine breeding biology. Taimen spawning, based on our observations, is a single pair event. The male prevented the approach of other males by launching intense attacks that extended for several meters away from the redd. Our data suggests that taimen females, differently from other salmonines, do not cover their eggs immediately after having spawned but rest for a variable number of minutes before covering them.

- by Deborah McLennan
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- Zoology, Ecology, Underwater, Fisheries Sciences

'City of waters', Venice represents a unique example of the challenges to be met in order to reconcile the conflicting demands of heritage preservation, infrastructural development and environmental management. This paper expands on the strategic value of Archaeological Impact Assessments (AIA) – studies initiated in response to development proposals that will potentially disturb or alter archaeological sites – by presenting a case study related to an AIA undertaken in Venice prior to the construction of a pipeline stretching across the central and south parts of its lagoon (Fusina Integrated Project). The morphology of this area is very complex and diverse, and it is characterised by the presence of numerous canals, shallows and shoals, a landscape (or, rather, a waterscape) shaped by countless natural and anthropogenic modifications that occurred over the past centuries. The AIA involved the analysis of a variety of datasets acquired through historical, archaeological, geomorphologic and palaeo-environmental investigations coupled with information retrieved by remote sensing imagery analysis and interpretation, and direct survey. The analysis of these datasets led to the identification of a new, large archaeological site located along the planned pipeline track. The elevated ‘archaeological sensitivity’ of this area caused a change in the project plan, resulting in the relocation of the original pipeline track at an early stage of the work.

Podvodna arheološka istraživanja rimske luke u uvali Janice provedena su u godinama 2004., 2011. i 2012. Iako su na Janicama prvo započeta istraživanja ranorimske luke, arheološki interes pomaknuo se prema obližnjem prapovijesnom nalazištu, koje je otkrio Marko Meštrov. Na početku istraživanja prapovijesnoga nalazišta identificirano je nekoliko položaja s većom gustoćom površinskih nalaza keramičkih ulomaka i kremenih alatki. Na tim položajima sljedeće su godine postavljene dvije arheološke sonde veličine 2 x 1 m. U obje sonde pronađena je velika količina ulomaka keramike, kremenih alatki i nešto ulomaka kostiju, a u sondi 1 pronađeni su drveni elementi već na 10 cm dubine. Svi ovi nalazi mogu se datirati u neolitik ili eneolitik. Značajna količina prikupljenih kremenih alatki, keramike i organskoga materijala te višeslojnost nalazišta svjedoče o naseljavanju ovoga položaja u dužem vremenskom razdoblju. Još uvijek se ne može pouzdano reći o kakvom je karakteru naselja ovdje riječ, a...

- by Mladen Pešić
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- Archaeology, Geology, Underwater Archaeology, Prehistory

We concur with the Contractor's recommendation that no further work is warranted along the Atchafalaya River portions of the study area. We also concur with the recommendations regarding reso, 'es along Bayou Shaffer. Due to project design changes, howe-, none of the Bayou Shaffer areas will be affected by the project. Therefore, no further cultural resource investigations are planned.

- by Allen Saltus
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- History, Navigation, Underwater, Surveys

In this paper, in order to overcome certain limitations of previously commercialized platforms, a new integrated unmanned surface vehicle (USV) and unmanned underwater vehicle (UUV) platform connected via underwater cable capable of acquiring real-time underwater data and long-time operation are studied. A catamaran-type USV was designed to overcome the limitations of an ocean environment and to play the role as the hub of power supply and communication for the integrated platform. Meanwhile, the UUV was designed as torpedo-shaped to minimize hydrodynamic resistance and its hardware design was focused on processing and sending the underwater camera and sonar data. The underwater cable driven by a winch system was installed to supply power from the USV to the UUV and to transmit acquired data form underwater sonar sensor or camera. Different from other previously studied cooperation system of USVs and autonomous underwater vehicles (AUVs), the merit of the proposed system is real-tim...

- by Hyeung-Sik Choi
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- Computer Science, Analytical Chemistry, Medicine, Sensors

- by AHMAD 'ATHIF BIN MOHD FAUDZI FKE
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- Engineering, ROV, Underwater

Large scale freshwater monitoring networks can passively capture sound for species detection or classification. The sheer volume of acoustic recordings in such systems requires in-network classification. Most of the recent work on bioacoustic in-network classification targets narrowband or shortdurations signals, which renders it unsuitable for classifying species that emit broadband short-duration signals. This paper proposes a method for broadband sound based classification for large scale aquatic monitoring networks. The method is based on the extraction of a small set of spectral and temporal features. We collect empirical fish sounds, using the case study of the spotted tilapia (Tilapia mariae) which is an invasive freshwater fish species in Australia, and extract spectral and temporal features with our method. We then evaluate the classification accuracy and precision of these features for detecting tilapia sounds against the performance of existing narrowband sound features. The results show that using logistic regression with our limited feature set yields the best performance. Surprisingly, performance slightly improves when we downsample the signal from 44.1 to 16 kHz, indicating that our method is well-suited for classification on embedded devices. We quantify the computational benefits of our approach for enabling broader longterm in-situ species tracking in underwater environments.

- by Navinda Kottege
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- Sound, Underwater, Classification, Tilapia
- by Samir Otmane and +1
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- Population Genetics, Augmented Reality, Evolution, Simulation

A discrete time-delay control (DTDC) law for a general six degrees of freedom unsymmetric autonomous underwater vehicle (AUV) is presented. Hydrodynamic parameters like added mass coefficients and drag coefficients, which are generally uncertain, are not required by the controller. This control law cancels the uncertainties in the AUV dynamics by direct estimation of the uncertainties using timedelay estimation technique. The discrete-time version of the time-delay control does not require the derivative of the system state to be measured or estimated, which is required by the continuous-time version of the controller. This particularly provides an advantage over continuous-time controller in terms of computational effort or availability of sensors for measuring state derivatives, i.e., linear and angular accelerations. Implementation issues for practical realization of the controller are discussed. Experiments on a test-bed AUV were conducted in depth, pitch, and yaw degrees of freedom. Results show that the proposed control law performs well in the presence of uncertainties.

In this paper, concerning underwater acoustic (UWA) communications, we propose a wavelet filter bank system as the extension of orthogonal frequency-division multiplexing system. We exploit the convolutional structure of a UWA channel and formulate the pilot-assisted channel estimation as a sparse recovery problem. Then, we investigate the restricted isometry property of the measurement matrix via eigenvalue analysis and Gershgorin circle theorem. The sparse recovery problem is proven to satisfy the restricted isometry property. Moreover, we also propose a low-complexity complex-field homotopy algorithm for sparse channel estimation, regarding the fact that the channel taps of each path are usually complex valued in practice. Simulation results show that the wavelet filter bank system achieves more accurate UWA channel estimation performance than orthogonal frequency-division multiplexing system under the same conditions of bandwidth, duration, data rate and channel profile. The proposed complex homotopy algorithm outperforms orthogonal matching pursuit (OMP) and stagewise OMP in both systems, whereas its computational complexity is similar to OMP. Copyright

- by Chenhao Qi
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- Compressed Sensing, Wavelet, Sparse Channel Estimation, Underwater

This paper presents a comprehensive overview of current deep-learning methods for automatic object classification of underwater sonar data for shoreline surveillance, concentrating mostly on the classification of vessels from passive sonar data and the identification of objects of interest from active sonar (such as minelike objects, human figures or debris of wrecked ships). Not only is the contribution of this work to provide a systematic description of the state of the art of this field, but also to identify five main ingredients in its current development: the application of deep-learning methods using convolutional layers alone; deep-learning methods that apply biologically inspired feature-extraction filters as a preprocessing step; classification of data from frequency and time–frequency analysis; methods using machine learning to extract features from original signals; and transfer learning methods. This paper also describes some of the most important datasets cited in the l...

- by Karl Sammut
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- Computer Science, Artificial Intelligence, Analytical Chemistry, Sonar

Remotely Operated Vehicle (ROV) for underwater exploration is typically controlled using umbilical cable connected to ground control station. Unfortunately, while it's used for power distribution and data transmission, it also obstruct the movement of ROV especially for shallow water (<50 cm). This paper proposed an alternative method for controlling ROV using wireless remote control system. This work also aims to explore the possibility of using RF wireless technology between 420-450 MHz as underwater communication system. Furthermore, the control system was used to manage actuators i.e. DC motor and bilge pump for maneuvring and picking small size cargo. To help the ROV to hold on a desired, Inertial Measurement Unit (IMU) is installed on board ROV within maximum deviation 0.2 m/s2. The prototype of the system has been successfully implemented and evaluated to confirm the functionality and the feasibility of the proposed approach.

Extended earlier work on aluminumewater burning underwater propulsion system. Mass estimation methodology extends energy density estimates for neutral buoyancy. In neutrally buoyant systems, benefits of fuel cell come with minimal range cost. Sensitivity analysis illustrates the influence of design and modeling assumptions. Predict up to 5-or 8-fold range improvement over available battery technology.

- by Christopher Cadou
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- Engineering, Modeling, Underwater, CHEMICAL SCIENCES

Underwater vehicles have many uses in civilian as well as military marine operations. Their applications range from maintenance and inspection on oil rigs to underwater salvage operations, and from scraping barnacles off the hulls of ships to searching a hostile bay for mines. For such vehicles to carry out their tasks it is advantageous to have high propulsive efficiencies. Efficiency for an underwater vehicle is measured by recording the amount of energy required to pull the vehicle through the water at a certain velocity and comparing that to the energy which the vehicle must expend to propel itself at the same velocity. Propellers are the primary conventional mechanism for water-based propulsion. The efficiency of a propeller scales up with specific load. This means that while a propeller works well on a vehicle with large available diameter, like a submarine, it has a rather limited efficiency for smaller autonomous vehicles where propellers must fit in cramped spaces. Addition...

- by David Barrett and +1
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- Water, Underwater, Scale, Detectors

ABSTRACT This article proposes a new formalism for the dynamic modelling of cables that can even be applied when they are submitted to cross flow of water or air. An important application is the case of umbilical cables used in remotely operated vehicles. The primary basis for the formulation is to assume that the continuous flexibility is represented by a discrete approach, consisting of rigid links connected by elastic joints, allowing movement in three dimensions. Each elastic joint allows three independent movements, called elevation, azimuth and torsion (twist). A significant contribution of the proposed formalism is the development of a compact equation that allows obtaining the Lagrangian of the system directly and automatically, regardless of the number of links chosen to form a chain of rigid bodies connected by flexible joints to represent the continuous flexibility of the cable. This formulation allows the construction of an algorithm for obtaining the equations of the dynamic model of flexible cables.

- by Sebastião Gomes
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- Engineering, Cognitive Science, Dynamics, Underwater

Underwater environments create a challenging channel for communications. In this paper, we design a novel receiver system by exploring the machine learning technique-Deep Belief Network (DBN)-to combat the signal distortion caused by the Doppler effect and multi-path propagation. We evaluate the performance of the proposed receiver system in both simulation experiments and sea trials. Our proposed receiver system comprises of DBN based de-noising and classification of the received signal. First, the received signal is segmented into frames before the each of these frames is individually pre-processed using a novel pixelization algorithm. Then, using the DBN based de-noising algorithm, features are extracted from these frames and used to reconstruct the received signal. Finally, DBN based classification of the reconstructed signal occurs. Our proposed DBN based receiver system does show better performance in channels influenced by the Doppler effect and multi-path propagation with a performance improvement of 13.2dB at 10 −3 Bit Error Rate (BER).

- by Dorien Herremans
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- Ocean Engineering, Computer Science, Artificial Intelligence, Acoustics

Underwater Wireless Sensor Networks (UWSNs) are getting growing interest because of wide-range of applications. Most applications of these networks demand reliable data delivery over longer period in an efficient and timely manner. However, resourceconstrained nature of these networks makes routing in a harsh and unpredictable underwater environment challenging. Most existing schemes either employ mobile sensors or a Mobile Sink (MS). However, cost of movement and sensors make such schemes infeasible. MS based schemes are not suitable for delay-sensitive large-scale applications. Unlike prior work, this paper presents a novel AUV-aided Efficient Data Gathering Routing Protocol (AEDG) for reliable data delivery. To prolong network lifetime, AEDG employs an Autonomous Underwater Vehicle (AUV) to collect data from gateways. To minimize energy consumption, we use a Shortest Path Tree (SPT) algorithm while associating sensor nodes with the gateways and devise a criterion to limit the association count of nodes. Moreover, the role of gateways is rotated to balance the energy consumption. To prevent data loss, AEDG allows dynamic data collection time to AUV depending up the count of member sensors for each gateway. Moreover, we formulate a MILP model, that increases network throughput as well as conserves energy by limiting the assignment of member nodes. The performance of the AEDG is validated through simulations. Simulation results demonstrate the effectiveness of AEDG in terms of various performance metrics.

- by Turki Alghamdi
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- Computer Science, Technology, Wireless Communications, Computer Networks

The objective of this research was to assess the effectiveness of using a multi-modal interface for adaptive automation (AA) of human control of a simulated telerobotic (remote-control, semi-autonomous robotic) system. We investigated the use of one or more sensory channels to cue dynamic control allocations to a human operator or computer, as part of AA, and to support operator system/situation awareness (SA) and performance. It was expected that complex auditory and visual cueing through system interfaces might address previously observed SA decrements due to unannounced or unexpected automation-state changes as part of adaptive system control. AA of the telerobot was based on a predetermined schedule of manual-and supervisory-control allocations occurring when operator workload changes were expected due to the stages of a teleoperation task. The task involved simulated underwater mine disposal and 32 participants were exposed to four types of cueing of task-phase and automation-state changes including icons, earcons, bi-modal (combined) cues and no cues at all. Fully automated control of the telerobot combined with human monitoring produced superior performance compared to completely manual system control and AA. Cueing, in general, led to better performance than none, but did not appear to completely eliminate temporary SA deficits due to changes in control and associated operator reorienting. Bi-modal cueing of dynamic automation-state changes was more supportive of SA than modal (single sensory channel) cueing. The use of icons and earcons appeared to produce no additional perceived workload in comparison no cueing. The results of this research may serve as an applicable guide for the design of human-computer interfaces for real telerobotic systems, including those used for military tactical operations, which support operator achievement and maintenance of SA and promote performance in using AA.

- by David B . Kaber
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- Robotics, Computer Science, Situation awareness, Adaptive Control
- by Ryan Eustice
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- Robotics, Oceanography, Autonomous Robotics, Marine Science

Tijekom razdoblja rimske prevlasti na Sredozemlju pomorski su putovi bili važni kanali za razmjenu robe između udaljenih dijelova Carstva. Ti su se putovi mijenjali tijekom stoljeća zbog političkih, gospodarskih i drugih razloga. Cilj je ovog rada predstaviti razlike u fluktuaciji uvoza i izvoza između istočne obale Jadrana, Italije i ostalih rimskih provincija na temelju nalaza amfora u Hrvatskoj iz razdoblja od 1. do 6. stoljeća. Amfore su zasigurno najčešći nalaz u istraživačkim kampanjama podvodne arheologije. Iako su uglavnom služile kao spremnici i ambalaža tijekom prijevoza robe, danas su bogat izvor informacija o teretu određenog broda: o podrijetlu, vrsti i veličini broda, lukama u kojima je pristajao i mnogočemu drugome. Isto tako, mnogo se informacija može doznati proučavanjem skupina amfora iz luka i drugih obalnih nalazišta.

- by Mladen Pešić
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- Geography, Underwater

Underwater photogrammetry provides a means of generating high-resolution products such as dense point clouds, 3D models, and orthomosaics with centimetric scale resolutions. Underwater photogrammetric models can be used to monitor the growth and expansion of benthic communities, including the assessment of the conservation status of seagrass beds and their change over time (time lapse micro-bathymetry) with OBIA classifications (Object-Based Image Analysis). However, one of the most complex aspects of underwater photogrammetry is the accuracy of the 3D models for both the horizontal and vertical components used to estimate the surfaces and volumes of biomass. In this study, a photogrammetry-based micro-bathymetry approach was applied to monitor Posidonia oceanica restoration actions. A procedure for rectifying both the horizontal and vertical elevation data was developed using soundings from high-resolution multibeam bathymetry. Furthermore, a 3D trilateration technique was also tes...

- by Gerard Pergent
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- Remote Sensing, Photogrammetry, Water, LiDAR

This chapter examines, in detail, the Geoarchaeological methods for both predicting and interpreting sites subjected to anthropogenic activities and taphonomic processes specific to inundated contexts. Garrison and Hale show that sediment particle-size, grain-size, and point-count studies coupled with debitage/micro-debitage analyses isolate middens deposits from those of natural origin. Chemical, faunal (primarily vertebrate), and floral proxies for anthropogenic activities were lacking, but they related the nature on inundated sites in a marine environment. The authors discuss how sea-level rise is coupled with these factors.

- by Jessica W Cook Hale
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- Engineering, Archaeology, Geoarchaeology, Underwater Archaeology

This paper addresses the question of redundancy management of a vectorial actuation system of an underwater robot. The approach focuses on the compensation of the actuators structural imperfections: dead-zone and motor's response disparity. The solution is based on the identification of a correction matrix which highly improves the open-loop response of the actuation system. The effect is formally shown in the linear case approximation. Experimental validation shows the performance of the solution.

- by lionel lapierre
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- Civil Engineering, Ocean Engineering, Underwater, Maritime Engineering

This effort exists within a group dedicated to the use of autonomous underwater vehicles, and buoyancy-driven gliders in particular, to support Navy missions. The group generally uses the Seaglider, developed at the Applied Physics Laboratory of the University of Washington (APL-UW), and develops or adapts instruments and glider behavior to support specific mission requirements. This group is informally called the Applied Seaglider Group, whose acronym, ASG, is also used to describe the Applied Seaglideritself. This report describes our efforts as part of the ONR Passive Autonomous Acoustic Monitoring (PAAM) program. The long-term goals of the PAAM program are as follows: Report Documentation Page Form Approved OMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.

- by Neil Bogue
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- Algorithms, Acoustics, Electronics, Underwater

A simple, low cost and continuous growth method for the production of well graphitized multi-wall carbon nanotubes is described. The growth takes place in an AC arc in water between two carbon electrodes. At a voltage of 40 V the arc is stable in the range of 85-45 A, lower current values help in increasing the fraction of carbon nanotubes in the product.

- by György Radnóczi
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- Technology, Carbon Nanotubes, Carbon Nanotube, Transmission Electron Microscopy