Talk on "Transmission Loss: a practical consideration" (Upcoming event)
Speaker: Dajun Tang, Principal Senior Oceanographer at Applied Physics Laboratory, University of Washington

AbstractTransmission Loss (TL) is a common engineering quantity in underwater acoustics that is a measure of sound propagation between the sound source and receivers in a varying ocean environment. Its applications can be found in both passive and active detection, as well as inversion of oceanographic parameters. The presentation will cover the definition, measurement, modeling, and application of TL through real data collected in the recent KOREX17 experiment. The goal is to go beyond textbooks to demonstrate how TL is measured and used in practical ocean acoustics. Feedback to this presentation is highly appreciated.

BiographyDajun (DJ) Tang received the B.S. degree from the University of Science and Technology, Hefei, China, in 1981, the M.S. degree from the Institute of Acoustics, Beijing, China, in 1985 and the Ph.D. degree in oceanographic engineering from the Joint Program of Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution, Cambridge/Woods Hole, MA, USA, in 1991. 

From 1991 to 1996, he was first an Assistant Scientist and then an Associate Scientist at Woods Hole Oceanographic Institution. In 1996, he moved to the Applied Physics Laboratory, University of Washington, Seattle, WA, USA, where he is currently a Principal Senior Oceanographer. His research encompasses acoustics in shallow water, including both field experiments and modeling. Currently, his focus is in the area of environmental impact on mid-frequency reverberation. 

Dr. Tang was Co-Chief Scientist for the Shallow Water 2006 (SW06) experiment and the Target and Reverberation Experiment (TREX13). He is a Fellow of the Acoustical Society of America.

Talk on "In-situ beam pattern estimation for seafloor acoustic backscatter measurements"
Speaker: Christian de Moustier, founder of 10dBx LLC

BiographyChristian de Moustier has over 30 years of experience in the design, testing, calibration, and operation at sea of numerous sonar systems for applications including swath bathymetry, seafloor acoustic backscatter imaging, natural seafloor methane seep detection, and ocean volume imaging. He has developed beamforming, detection and geo-referencing algorithms for such sonars. He has worked offshore on over 90 seagoing experiments, 30 of which as Chief Scientist.

In January 2014, C. de Moustier founded 10dBx LLC, a scientific consulting company specializing in underwater acoustics and ocean engineering. Previously, he was a Principal Scientist at HLS Research, Inc. (2009-2013); a tenured full professor of Electrical and Computer Engineering/ Ocean Engineering at the University of New Hampshire, Durham, NH (2002- 2008); and he held combined positions of associate researcher, lecturer, and academic administrator for shipboard technical support, at the Scripps Institution of Oceanography (1986- 2001). He is Member of the American Geophysical Union, a Fellow of the Acoustical Society of America (1996), and a Senior Member of the IEEE. He served 6 years as Editor in Chief of the IEEE Journal of Oceanic Engineering (2005-2010).  C. de Moustier received the IEEE Oceanic Engineering Society’s Distinguished Technical Achievement Award (2014) for contributions to acoustic remote sensing of the ocean volume and boundaries. He was elected president of the IEEE Oceanic Engineering Society for a 2-year term (2017-2018).

Talk on "Ocean Science in the Age of Marine Robots"
Speaker: Dr. James Bellingham, founding director of Center of marine robotics at Woods Hole Oceanographic Institution 

Date: 23rd March (Friday)
Time: 10AM

Abstract: For decades scientists have studied the ocean by going to sea on ships. Today we increasing see the ocean through the senses of our robots. Ocean science is in the midst of a revolution. We have been, at best, occasional visitors to the largest and most complex habitat on the planet. However, developments in diverse fields of technology are converging to enable a permanent presence in the ocean, not by humans, but by our robotic proxies. Mobile robotic vehicles are a reality, and are taking a variety of forms and shapes. They map the deep seafloor, find lost aircraft, make measurements beneath sea-ice in the Arctic, and patrol our coastal waters. Early successes are leading to widespread adoption. While early marine robots were tied to support ships, newer systems can operate on their own. Future systems will work in robotic teams. We are not far from a future where global networks of robots make the hidden ocean visible. 

: Jim Bellingham is a pioneer in the development of autonomous marine robots. He has led and participated in research expeditions around the world from the Arctic to the Antarctic. He is the founding Director of the Center of Marine Robotics at the Woods Hole Oceanographic Institution, founded the Autonomous Underwater Vehicles Laboratory at MIT, and co-founded Bluefin Robotics. He serves on numerous advisory committees and boards, including the Secretary of the Navy Advisory Panel and several National Academies studies . He Chairs the Naval Research Advisory Committee, which advises the Secretary of the Navy. Jim’s awards include the Lockheed Martin Award for Ocean Science and Engineering, and the MIT Fourteenth Robert Bruce Wallace lecturer. Jim received S.B., S.M., and Ph.D. degrees in physics from the Massachusetts Institute of Technology.

Singapore AUV Challenge (SAUVC) 2018

Date: March 9-12, 2018
Venue: Singapore Polytechnic

SAUVC 2018 was a huge success! A big thank you to all the sponsors, participating teams and the volunteers, without whom it wouldn't have been possible. 

Find the results here. Look for updates, pictures and videos on the Facebook Page.

Speaker: Eric de Trétaigne (Alseamar)

SEAEXPLORER (( an underwater glider that can be used for ocean monitoring and exploration.

IEEE OES Annual Workshop and AGM 

Visit our facebook group here.

Date: Nov 10, 2017
Venue: S2S conference room, Tropical Marine Science Institute, National University of Singapore

Talks given:

1. Global Scale Underwater Sound Modeling: Underwater low-frequency sound can travel great distances in the oceans' and sound triggered in the sea by the mechanical energy transfer from the Earth's crust. (e.g., earthquakes or volcanoes) and by the energy transfer occurring at the water surface (e.g., wave storms or ice-quakes) can e detected at thousands of kilometers from the source. However, source characterization based on recorded sound data analysis involves significant scientific challenges and uncertainties. A variety of geological and physical oceanographic features can cause horizontal refraction, reflection and diffraction on global scale sound propagation. In this regard, three-dimensional underwater sound models are required for accurately predicting global scale sound propagation of oceanic sound. A three-dimensional sound propagation model using the parabolic equation (PE) approximation and the Split-Step Fourier (SSF) method is used. Numerical results are compared with field data recorded by hydrophones at great distances from the source. Based on the case study, a discussion and recommendation on the global scale underwater sound modeling and data analysis are presented.
Speaker: Dr. Tiago Oliveira

2. A new genus and species of abyssal sponge commonly encrusting polymetallic nodules in the Clarion-Clipperton Zone: The Clarion-Clipperton Zone (CCZ) in the East Pacific is a vast region targeted for deep-sea mineral exploration, for which there are almost no published taxonomic data. Here we describe Plenaster craigi gen. nov. sp. nov. from depths of around 4000 m in the eastern CCZ polymetallic nodule province. Despite over 40 years of intense exploration in the area, we reveal that P. craigi sp. nov. is the most abundant sponge and the most common metazoan encrusting on nodules in our study area at the eastern CCZ. It has a mean abundance of 15.3 + 8.9 individuals per m2 across 11 stations in a 30 X 30 km study site nested within the Singapore exploration area. The white encrusting sponge is filled with spheroxyasters with occasional styles protruding the surface. Plenaster craigi sp. nov. is morphologically similar to genera from three different families in two orders: Timea (Timeidae; Tethyida); Hemiasterella and Leptosastra (Hemiasterellidae; Tethyida); and Paratimea (Stelligeridae; Axinellida). However, based on the molecular (COI and 28S) phylogenetic trees generated in this study, P. craigi sp. nov. was located in the Order Axinellida and appeared to be distant to Timea, Hemiasterella, Leptosastra, and Paratimea. We propose a new genus for our material to be placed provisionally in the family Stelligeridae. Plenaster craigi sp. nov. being an abundant metazoan encrusting on nodule and easily identified filter-feeding animal is a potentially indicator species for future mining impacts in the eastern CCZ, and possibly across the entire CCZ.
Speaker: Dr. Lim Swee Cheng

3. Swarming technology for pervasive monitoring of the marine environment: 
Swarm Robotics offers a promising approach to the pervasive monitoring of marine environments. Traditional monitoring techniques rely on either a single autonomous robot—autonomous surface vehicle—or a fixed network of sensors. Neither existing technology is suitable or efficacious for the robust monitoring and tracking of dynamic environmental features at the surface of aqueous environments. There is a pressing need for small, low-cost and rapidly deployable autonomous buoys. One powerful source of inspiration comes from the process of self-organization and swarming, observed throughout the natural world. We present the design, construction and testing of the largest swarm of buoys ever built. To date, we have deployed and tested a system of up to 50 units that are dynamically deployed over large surface areas of an uncontrolled open-water environment without any supporting infrastructure.
Speaker: Dr. David Mateo 

4. Simulation and Design of Lithium-Ion Battery Power System for Underwater Applications: 
A large format lithium-ion battery stack power system is designed for electric-propelled underwater robotic vehicles (URVs): manned, remotely-operated and autonomous for various deep water applications. The large format lithium-ion battery stacks are chosen for their high energy density, modularity and ready availability. To increase their output power rating, many battery stacks can be connected in series and/or parallel in an enclosure. We propose to design and develop a smart battery management system (BMS) with high efficiency active cell balancing technology and intelligent self-learning battery state of charge (SOC) estimation for the lithium-ion battery. The proposed active cell balancing technology will lead to longer endurances and lengthens the lifetime of the battery for underwater applications. Besides, the 2kWh battery stack module with BMS system is scalable and swappable to provide higher power capacity and increase flexibility in usage. A built-in pressure-resistance enclosure will eliminate extra battery pressure chamber and associated risks, thereby increasing power system reliability amidst high pressures of sea water. The lithium-ion battery stack power system developed has high potential for commercialization and the effects of this project will drive academic knowledge and applied research works in various deep water applications using backup or actual power supply in electric propulsion of underwater robotics vehicles, subsea equipment, offshore oil rig platform monitoring, underwater ship’s hull inspection, deep-ocean surveys in preparation for oil fields, subsea systems inspection, maritime energy storage systems and environmental surveying.
Speaker: Dr. Cheng Siong Chin

5. Team Bumblebee's Novel Experience Competing in the 2016 Maritime RobotX Challenge
Speaker: MrSteven Harta Prawira

6. 3D Sub-bottom Profiling - High Resolution 3D Imaging of Shallow Subsurface Structures and Buried Objects: New developments in sub-bottom profiling brings 3D reflection seismics, routinely used in hydrocarbon exploration, to the shallow survey market by down-scaling the conventional techniques to achieve decimetre resolution imaging of the top tens of metres of the sub-surface in three dimensions. These advances have been made possible by improvement in digital data acquisition and position accuracy. Shallow high resolution sub-bottom profiling currently still relies mainly on single-channel 2D methods. In contrast to the 2D methods that produce individual vertical cross-sections of the sub-surface, the 3D method combines data collected over the survey area into a data volume. The data can then be viewed in any orientation independent of the acquisition direction, delineating structures and objects in three dimensions with enhanced data quality and resolution. The GeoChirp 3D system uses a surface towed structure that comprises source transducers, operating on a bandwidth of 1.5 to 13 kHz, and 60 hydrophone groups mounted on a rigid array. It is positioned using RTK-GPS and a motion reference unit. The integrated deck-end hard and software component combines sonar and navigation data into industry standard SEGY format that are processed and interpreted using readily available software packages. Application examples include small object detection and identification surveys as well as marine archaeology, engineering and geological and geophysical projects.
Speaker: Dr. Martin Gutowski

Pictures from the workshop

OES Social Gathering 2017

OES had its annual social networking get-together on the 21st of July. Members and their family participated in an exciting bowling session followed by dinner at Jack's place! 

Pictures from the event




Talk on "3D Acoustic Modeling in a Dynamic Environment" 

Date: Monday, July 17, 2017  
Time: 4-4:30PM
Venue: S2S conference room, Tropical Marine Science Institute, National University of Singapore 

Talk on "Design Improvements of an Underwater Low Frequency Projector Based on Clarinet Acoustics" 
Speaker: Veronica Koh, DSO National Laboratories

Date: July 11, 2017
Venue: S2S conference room, Tropical Marine Science Institute, National University of Singapore 


Low frequency (ka«1) underwater projectors are desired for long range sonar applications and oceanography due to their low absorption losses. However, their inherent design constraints often lead to large size and high cost. This thesis discusses several design improvements made to a prototype of a low cost low frequency underwater projector based on clarinet acoustics. First, a new pressure chamber was designed and built to improve water sealing, ease of assembly, as well as interface with a larger diameter pipe to reduce occurrence of cavitation. Lab measurements of the improved prototype were made using both PVC and Aluminum based resonators, with two different reed configurations and tested at different blowing pressures. Analysis of measurement results showed how playing frequency varied with blowing pressure and resonator type. In particular, intermodulation products generated at high blowing pressures resulted in perception of a large drop in playing frequency. Distortion of the sound generated was also calculated and shown to increase at higher blowing pressures. Second, improvements in the equivalent circuit model of the underwater clarinet were made by including effects of pressure chamber impedance and elastic wall. The chamber and resonator impedances were first modeled using COMSOL Multiphysics. Two-resonance and four-resonance equivalent circuit models were then derived to fit the acoustic impedances measured in COMSOL. Overall system impedance analysis and time domain simulation of the improved model were also performed. Results from the improved model provided explanation for the trends observed during measurements. Finally, a combination of measured sound pressure level and modeling was used to predict sound pressure level in the far field. The efficiency in converting input pneumatic power to acoustic power was also estimated using the model.

Speaker: Ms. Veronica Koh, DSO.

Talk on "The Role of Bubbles in High Frequency Underwater Noise: From the Tropics to the Arctic"

Date: April 26, 2017
Time: 3 pm
Venue: S2S conference room, Tropical Marine Science Institute, National University of Singapore 

About the Speaker: 

Dr. Grant Deane is a Research Oceanographer at the Marine Physical Laboratory, Scripps Institution of Oceanography. He obtained his B.S., University of Auckland, New Zealand, followed by his M.S. from University of Auckland, New Zealand. He obtained the Ph.D. from the University of Oxford, England. He has been awarded the A. B. Wood Medal in 1997 and the Sagar Geophysics Prize in 1986 by Auckland University. His research interests include propagation and scattering of underwater sound, bubble acoustics, energy dissipation and air entrainment by breaking gravity waves, oceanic ambient noise, and bioluminescence from Dinoflagellates.

Singapore AUV Challenge (SAUVC) 2017

Singapore AUV Challenge was held from March 10-13. It saw a higher turnout than ever, with over a 100 participants. 31 teams registered, of which 13 teams made it to the competition. 10 teams qualified for the competition. The event was well-appreciated by the attendees and participants. 
Following are the prize-winners at SAUVC 2017: 

Fastest completion of tasks, Joint Winners:
Far Eastern Federal University/Institute of Marine Technology Problems, Russia and
Center for Advanced Studies in Engineering, Pakistan

Team with maximum tasks accomplished: 
Northwestern Polytechnical University, China

Youngest finalist team: 
Paya Lebar Methodist Girls' School (Secondary), Singapore

Most liked photography competition: 
Center for Advanced Studies in Engineering, Pakistan

AUV Workshop: 
SAUVC 2017 was followed by an AUV workshop on 13th March. The following talks were delivered, apart from team presentations on their AUVs:

1. William J. Kirkwood, Senior R&D Engineer, Monterey Bay Aquarium Research Institute (MBARI), USA
Topic: What is Autonomy and when does it become Artificial Intelligence

2. Nikola Miskovic, Professor, Faculty of Electrical Engineering and Computing, University of Zagreb, Croatia
Topic: Cooperative and not-so-cooperative marine robots

3. Stefan Williams, Professor, Marine Robotics, Sydney University, Australia
Topic: Autonomous Underwater Vehicles Applications in Marine Imaging

Seminar Series and Annual General Body Meeting

Date and Time: 1st November, 1.30 pm - 6 pm


    1. Design of a hybrid submersible UAV for target location and surveillance,  Speaker:  Dr. Daniel T. H. New
    2. Buoyancy driven Autonomous profiling float for shallow waters, Speaker: Vinoth Viswanathan

Talk on "Changing perspectives on the acoustic ecology of deep-diving toothed whales: From individual biosonar parameters to collective foraging strategies"

Date and Time: 4 July, 11 am

AbstractThe field of cetacean bioacoustics has changed considerably the last two decades, with advances in ultrasonic field recorders, portable hydrophone arrays, and miniature recording tags paving the way for new discoveries. Here I will walk through a few highlights from our studies of toothed whale biosonar, emphasizing how echolocation parameters scale with body size and how differences in foraging ecology have shaped the biosonar properties of these animals, yet kept the width of the sonar beam practically constant despite 3 orders of magnitude differences in body weight. I will then focus in on two species of highly social, deep-diving pilot whales that we have studied off the coast of Tenerife and in the Mediterranean Sea. Here we are using simultaneously deployed acoustic tags (DTAGs) to study dive collective decision making in heterogeneous social groups. I will demonstrate how animals coordinate foraging dives and how they maintain group cohesion using different modes of social communication, and finally discuss how long-finned pilot whales seem to employ a distributed, biosonar based foraging strategy where they may benefit from the presence of other group members in their search for better food patches.

About the speakerFrants H. Jensen, Junior Fellow, Aarhus Institute of Advanced Studies, Aarhus University, Denmark, and Princeton University. Frants is currently working on the project "Movement coordination, leadership and collective foraging in matrilineal toothed whales".

IEEE Distinguished Lecture on "Coastal Ocean Radars: Results and Applications"

Date and Time: 7 April, 11 am

Abstract: A descriptive overview of the Australian Coastal Ocean Radar Network is given with some background about how sites are selected and configured. A suite of results and applications emanating from the ACORN network is presented, including Lagrangian Tracking; assistance to management in the Great Barrier Reef Marine Park; assistance in the salvage of a grounded ship; and the observation of cold fronts in the Southern Ocean.

About the speaker: Professor Mal Heron is Chief Researcher in the Marine Geophysical Laboratory at James Cook University in Townsville, Australia, and is a Consultant with Portmap Remote Ocean Sensing Pty Ltd. His PhD work in Auckland, New Zealand, was on radio-wave probing of the ionosphere, and that is reflected in his early ionospheric papers. He changed research fields to the scattering of HF radio waves from the ocean surface during the 1980s. Through the 1990s his research has broadened into oceanographic phenomena which can be studied by remote sensing, including HF radar and salinity mapping from airborne microwave radiometers . Throughout, there have been one-off papers where he has been involved in solving a problem in a cognate area like medical physics, and paleobiogeography. Occasionally, he has diverted into side-tracks like a burst of papers on the effect of bushfires on radio communications. His present project of the Australian Coastal Ocean Radar Network (ACORN) is about the development of new processing methods and applications of HF radar data to address oceanography problems. He is currently promoting the use of high resolution VHF ocean radars, based on the PortMap high resolution radar.

The Singapore AUV competition (SAUVC) is an annual AUV competition organized by IEEE OES Singapore with focus on University and Polytechnic students. This year, the fourth edition of this robotics competition was organized successfully from March 4-6 at Singapore Polytechnic. The event was held over three days, and saw participation from 11 stud
ent teams from 6 countries. SAUVC attracted an attendance of more than 200 people, and received good feedback from the attendees and participants alike. More details 

Comprehensive list of previous events (except SAUVC):

 Event  Speaker Date
 In-situ beam pattern estimation for seafloor acoustic backscatter measurements Dr Christian de Moustier 25th May, 2018
 Ocean Science in the Age of Marine Robots Dr James Bellingham 23rd March, 2018
 Talk on SEAEXPLORER Eric de Trétaigne 1st February, 2018
 Global scale underwater sound modeling Dr Tiago Oliveira 10th November, 2017
 A new genus and species of abyssal sponge commonly encrusting polymetallic nodules in the Clarion-Clipperton Zone Mr Lim Swee Cheng 10th November, 2017
 Swarming technology for pervasive monitoring of the marine environment Dr David Mateo 10th November, 2017
 Simulation and Design of Lithium-Ion Battery Power System for Underwater Applications Dr Cheng Siong Chin 10th November, 2017
 Team Bumblebee's Novel Experience Competing in the 2016 Maritime RobotX Challenge Mr Steven Harta  Prawira 10th November, 2017
 3D Sub-bottom Profiling - High Resolution 3D Imaging of Shallow Subsurface Structures and Buried Objects Dr Martin Gutowski 10th November, 2017
 IEEE OES Members social get-together night - 21 July, 2017
 3D Acoustic Modeling in a Dynamic Environment Dr. Y. T. Lin 17 July, 2017
 Design Improvements of an Underwater Low Frequency Projector Based on Clarinet Acoustics Ms. Veronica Koh 11 July, 2017
 The Role of Bubbles in High Frequency Underwater Noise: From the Tropics to the Arctic Dr. Grant Deane 26th April, 2017
 Buoyancy driven Autonomous profiling float for shallow waters Mr Vinoth Viswanathan 1st Nov, 2016
 Design of a hybrid submersible UAV for target location and surveillance Dr. Daniel New  1st Nov, 2016
 Unmanned Marine Vehicle Developed at Harbin Engineering University Dr. Jiang Dapeng 27 Oct, 2016
 Perspectives on acoustic ecology of deep-diving toother whales: Biosonar parameters to collective foraging strategies  Dr. Frants H. Jensen 4 July, 2016
 Underwater Vehicle development and Instrument Integration activities Dr. Bill Kirkwood 4 Mar, 2016
 Coastal Ocean Radars: Results and Applications (IEEE Distinguished lecture)  Dr. Mal Heron  7 Apr, 2016 
 Speech communication under shallow water channels Dr. Dong-Shen 28 Jan, 2016
 Channel-awareness underwater acoustic communication and network Dr. Tong Feng 28 Jan, 2016
 Recent Developments Enhancing Autonomous Solutions for AUVs  Mr. Ioseba Joe Tena 21 Jan 2016
 Australia studies of ambient sea noise and whale acoustics Dr. Doug Cato 10 Dec, 2015
 Advances in Long Range Current Profiling with Composite Broadband Transducers. Mr David Velasco 9 Oct, 2015
 Zinc  Complexing  Ligands  In  A  Tropical  Pristine  River: Understanding
 The  Connection  To  Regional  And  Global  Distributions Of  Zinc  Ligands  And  Bioavailable  Zinc.
 Dr. Gonzalo Carrasco 9 Oct, 2015
 Estimating geoacoustic parameters using underwater acoustic remote sensing methods. Dr. Daniel Tan Bien 9 Oct, 2015
 Modeling and Control of Soft Body Underwater Fin Locomotion. Prof. Pablo Valdivia 9 Oct, 2015
 Richard Coe expedition Mr. Richard Coe 21 Aug, 2015
 Underwater Robotics and Underwater Acoustics - Current and Future Developments Mr. Satish Ramachandra 28 Jul, 2015
 Development of Ocean Acoustic Waveguide Remote Sensing Dr. Nicholas C. Makris, Dr. Purnima Ratilal 8 Dec, 2014
 The effect of nearby bubbles on hydrophone arrays Dr. Richard Lee Culver 7 Sep, 2012