Student poster winners.
The 34th Student Poster Program of the OCEANS Conferences was held at OCEANS’14 MTS/IEEE Taipei, at the Taipei International Convention Center, from April 7 to April 10. As for the previous Student Poster Competitions, outstanding posters describe the work that the students were presenting and were particularly appreciated by the attendees of the conference. Moreover, the student participants greatly appreciated the opportunity to display, exchange and describe their research work to the community.
Jiahn-Horng Chen and Chung-Chen Chang organized the program as local coordinators and Philippe Courmontagne from IEEE OES. For this 34th edition, 79 abstracts were received and 16 were selected, not without difficulty given the high quality of the received abstracts. The students were from schools in Europe, Asia and the USA. The program was supported by funding from the US Navy Office of Naval Research, which enabled the students to attend the conference. A team organized by IEEE OES judged the posters. The student award winners were announced during the Gala Dinner at the Grand Hotel.
Prof. Philippe Courmontagne opened the awards ceremony and presented each student with a Certificate of Participation in the OCEANS’14 MTS/IEEE TAIPEI. Then, the Gala Hostess introduced Prof. Jiahn-Horng Chen, who presented the third place winner to Ugo Moreaud, from France. Next, Rick Spinrad, MTS elected President, presented the second price to Marta Ramírez-Pérez, from Spain. René Garello, IEEE OES President, presented the first prize, the “Norman Miller Prize”, to Jeff Dusek, from USA, for his poster entitled “Carbon Black-PDMS Composite Conformal Pressure Sensor Arrays for Near-Body Flow Detection”. All the students received a round of applause for their accomplishments and participation in the Student Poster Program of Taïpei.
Student poster award ceremony.
The roster of students and schools are:
Raul Bardaji, ICM-CSIC
Arnau Carrera, University of Girona
Jeff Dusek, Massachusetts Institute of Technology
Jun-Kai Guo, National Taiwan University
Chien-Wen Lin, National Taiwan University
Yukang Liu, University of Kentucky
Zhiquan Liu, Harbin Engineering University
Ivan Masmitja, SARTI-UPC
Jonathan McColgan, University of Glasgow
Ugo Moreaud, DCNS/IM2NP
John Naglak, Fort Lewis College
Nicole Nichols, University of Washington
Jen-Ping Peng, National Taiwan Ocean University
Marta Ramírez-Pérez, Institute of Marine Sciences ICM-CSIC
Ming Zhang, Zhejiang University
Songsong Zhu, Zhejiang University
Student Poster Abstracts
Raul Bardaji, ICM-CSIC, Comparing water transparency measurements obtained with low-cost citizen science instruments and high-quality oceanographic instruments
Abstract—The low cost moored system KdUINO allows to measure parameters related to water transparency, specifically the diffuse attenuation coefficient parameter. In this contribution, its measurements are compared with other high precision scientific commercial instrument in order to estimate the sensor measurement error.
Arnau Carrera, University of Girona, An intervention-AUV learns how to perform an underwater valve turning
Abstract—Intervention autonomous underwater vehicles (IAUVs) are a promising platform to perform intervention task in underwater environments, replacing current methods like remotely operate underwater vehicles (ROVs) and manned submersibles that are more expensive. This article proposes a complete system including all the necessary elements to perform a valve turning task using an I-AUV. The knowledge of an operator to perform the task is transmitted to an I-AUV by a learning by demonstration (LbD) algorithm. The algorithm learns the trajectory of the vehicle and the end-effector to accomplish the valve turning. The method has shown its feasibility in a controlled environment repeating the learned task with different valves and configurations
Jeff Dusek, Massachusetts Institute of Technology, Carbon Black-PDMS Composite Conformal Pressure Sensor Arrays for Near-Body Flow Detection
Abstract—In nature, fish rely on the lateral line sensory organ for many critical behaviors including obstacle detection, prey tracking, and schooling. Acting in a similar fashion to an array of pressure sensors, the lateral line allows for the detection of near-body flow structures such as vortex shedding and separated flow. Drawing on the lateral line for inspiration, conformal and highly sensitive pressure sensor arrays were investigated using a carbon black and polydimethylsiloxane (CBPDMS) composite as a piezoresistive sensing material. In order to achieve the sensitivity necessary for the detection of hydrodynamic stimulus while maintaining the flexibility and robustness for use in the maritime environment, a porous CBPDMS composite was developed using sugar as a sacrificial scaffold. When the sacrificial scaffold was dissolved, the Young’s modulus of the porous composite was reduced nearly two orders of magnitude compared to solid CBPDMS, leading to an order of magnitude increase in array sensitivity. The porous CBPDMS active material was packaged as an underwater sensing array using multiple encapsulation methods, and successfully tested using water wave stimulus in the MIT Towing Tank.
Jun-Kai Guo, National Taiwan University, Improving Visibility and Fidelity of Underwater Images Using an Adaptive Restoration Algorithm
Abstract—When light is transmitted in water from a subject to an observer, it is scattered and absorbed by the unstable environment such as suspended particles and turbid water. Due to these phenomena, underwater images usually have poor quality including low contrast, blurring, darkness, and color diminishing. In this paper, we propose a new underwater image restoration algorithm that consists of two major phases: visibility restoration and fidelity restoration. In the first phase, underwater images are observed similar to haze images because they have the same problems of low contrast and color shifting. This motivated us to use the haze removal technique, namely, dark channel prior, to dehaze underwater images. Subsequently, in the second phase, we equalize the color mean in each RGB (red, green, blue) channel to balance the color. Then transform the color space from RGB to HSV (hue, saturation, value) color space to adjust S channel to make the image color more natural.
Finally, we adjust V channel according to the brightness value of RGB to enhance the contrast. Preliminary results indicated that the proposed method effectively improved visibility and fidelity of underwater images.
Chien-Wen Lin, National Taiwan University, T-wave observations on ocean-bottom seismometers offshore Eastern Taiwan
Abstract—T waves excited by earthquakes propagate along the SOFAR channel with low transmission loss, and therefore can be recorded on land-based seismic stations and hydrophones located thousands of kilometers away from earthquake epicenters. Early T-wave observations are mostly based on recordings by landbased stations due to the mechanics of the energy conversion of acoustic waves into seismic phases. Recently, T-wave signals have also been detected by ocean-bottom seismometers (OBSs) at deep ocean basin offshore eastern Taiwan, raising the question of how deep ocean environment affects the generation and propagation of T-waves. In this study, to understand how acoustic energy scatters and interacts with different seafloor topography, we apply the acoustic ray theory to simulate acoustic propagation in the presence of realistic seafloor topography and sound speed profile. Our simulations indicate that seafloor topography indeed affects the acoustic propagation pattern, part of which may reach deep ocean regions. We also simulate seismic energy of T-waves by stacking energy coming from a series of potential conversion points within a specific time-window. The stacked energy distribution expresses a pattern similar to the envelope function of T-waves, indicating that the long-lasting waveform may result from a series of seismic-acoustic conversion processes.
Yukang Liu, University of Kentucky, Low-Frequency Sound Transmission through Water-Air Interface: A Comparison between Ray and Wave Theory
Abstract—Studying low frequency sound transmission through water-air interface can help understand airplane-generated sound for acoustic remote sensing and effects of airborne sources on marine life. In this paper ray theory and wave theory are utilized to evaluate the acoustic transparency. Ray theory is first used to calculate the energy of the plane and spherical wave that transmits from water to air. Wave theory is then utilized to study spherical wave transmission through water-air interface. By comparing the results obtained from two theories, it is found that acoustic transparency can be derived using both ray and wave theory. Because acoustic transparency derived using ray theory is slightly smaller than that of the wave theory, it is thus called Enhanced Transparency as opposed to Anomalous Transparency proposed by Godin. By incorporating the inhomogeneous wave, wave theory does provide more significant transparency, especially in low frequencies. The results have been further extended to liquid-gas interface.
Zhiquan Liu, Harbin Engineering University, Ship roll stabilization control with low speed loss
Abstract—Large roll motion induced by waves can severely affect the ability of vessels and the speed will loss due to added resistance which caused by ship motions, especially in moderate to high sea states. With increasing needs of fuel efficiency and greenhouse gas (GHG) emissions, the effect of added resistance on surface ship performance must be considered when a ship fin stabilizer control system is designed. In this paper, we investigate basic principles of added resistance in oblique waves and ship calm water resistance. An alternative approach for reducing speed loss while keeping the satify roll reduction percentage, is proposed by controlling both roll and roll rate at the same time.
A double nonlinear generalized minimum variance (NGMV) controller is used for achieving this objective. Finally, the effectiveness of the method is demonstrated.
Ivan Masmitja, SARTI-UPC, Buoyancy model for Guanay II AUV
Abstract—The AUV Guanay II is a vehicle developed by SARTI research group of Universitat Politècnica de Catalunya with the objective of providing a platform for measuring oceanographic variables, such as the temperature and salinity of the water column. In the vertical dive is important not to disturb the environment to avoid influencing in the measurements. For this reason a variable buoyancy (VB) system to do the vertical immersions has been designed. This paper presents the model designed to change the buoyancy of the vehicle and the tests both laboratory and field.
Jonathan McColgan, University of Glasgow, Coordination of a School of Robotic Fish Using Nearest Neighbour Principles
Abstract—Autonomous Underwater Vehicles (AUVs) are Unmanned Underwater Vehicles (UUVs) that are able to function without direct control from a human operator. Consequently, they have a wide range of applications from scientific research of the oceans to military applications such as maritime surveillance. However, there is now the demand for AUVs to be operated within a multi-vehicle scenario to allow large areas of the ocean to be monitored simultaneously. However, in order for this to become a reality algorithms have to be created that ensure that a group of AUVs could be self-organising. Therefore, using a validated mathematical model of a biomimetic robotic fish (called RoboSalmon) and taking inspiration from nature, this paper outlines the implementation of co-ordination algorithms based upon the behavioural mechanisms exhibited by schools of fish to allow a group of AUVs to become self-organising. The algorithms implemented are based on two different methodologies known as the Discrete and Continuous Behavioral Zone methodologies. The results obtained demonstrated that although both methodologies result in the formation of a school structure, the results obtained from the Continuous Behavioral Zone (CBZ) methodology were more resilient to changes in parameters associated with school structures and therefore these algorithms provided the most effective way to allow a group of AUVs to be considered as self-organising.
Ugo Moreaud, DCNS/IM2NP, Underwater acoustic signal denoising using multi-directionnal masks on time-frequency representations
Abstract —This paper addresses the problem of underwater acoustic signal denoising. This field has been mainly investigated as it allows signal-to-noise ratio enhancement, a prerequisite to any data interpretation. Underwater acoustic signal denoising shares similarities with speech signal processing since both deals with acoustic signals, consequently it is possible under some manipulations to use speech processing top methods for underwater acoustic signal denoising. The acoustic underwater signal has different signatures than the speech signal, so it makes the usual well known speech denoising methods sub-optimal. In this paper, we present a new way to denoise the underwater acoustic signal, which is based on a statistical approach using multi-directional masks on the audio signal time-frequency representation. Compared to the well-known denoising methods, like Wiener filter and Ephraim and Malah algorithm, this approach results in less residual noise (still colorless) and better signal of interest enhancement from its noisy environment.
Nicole Nichols, University of Washington, Weakly Supervised Click Models for Odontocete Species Classification
Abstract—This paper addresses the problem of automatic learning of statistical models of clicks for odontocete species classifications, particularly focusing on improving accuracy of the classifier by iteratively identifying click-like sounds that are likely to be noise and removing these from the model training set. The algorithm is weakly supervised in that no hand-labeled click regions are available, but knowledge of the species present during the time of recording is used. Experiments classifying which of the three species are present show 7–12% reduction in cross species error from a small number of iterations, but also show a need for improved feature extraction to normalize for recording condition bias.
Marta Ramírez-Pérez, Institute of Marine Sciences ICM-CSIC, Do hyperspectral transmissometers allow us to go one step further on the analysis of particulate matter characteristics in water samples?
Abstract—Several studies have been carried out to investigate the correlation between the spectral shape features of the beam attenuation coefficient and the particulate matter characteristics in seawater, but little attention has been paid to the spectral resolution of these measurements. For this reason, the potential of the new hyperspectral transmissometer VIPER (TriOS GmbH), with 1.7 nm spectral resolution, has been evaluated in this study and compared with lower resolution and multispectral based approaches (e.g. ac-9 or ac-s -with 4 nm resolution- from WETLabs Inc.) in order to evaluate whether any additional information about water composition can be retrieved from a spectral shape-based assessment. In this way, this study proposes a statistical-based method –a Hierarchical Cluster Analysis (HCA) using the cosine distance as similarity value- which allows discriminating suspended sediment samples with different particle size distribution (PSD) based on the attenuation spectral shape features. Finally, the effects of both particle size and concentration on the spectral shape have been analyzed separately. The results confirmed that the beam attenuation spectral features are in first-order driven by particle concentration, which means that a prior knowledge of particulate matter concentration is required in order to classify sediment samples according to their particle size. This approach based on hyperspectral attenuation measurements to characterize the PSD has been demonstrated a potential alternative compared to the traditional methods such as Coulter Counter or the particle size analyzer LISST 100X, which are much more expensive and timeconsuming approaches.
John Naglak, Fort Lewis College, Design and Development of a Sampling Platform to Study Long Distance Seed Dispersal
Abstract—Recent theoretical research has shown that ocean currents and wind interact to disperse seeds over long distances among isolated landmasses. Dispersal of seeds among isolated oceanic islands, by birds, oceans and man, is a well-known phenomenon, and many widespread island plants have traits that facilitate this process. Crucially, however, there have been no mechanistic vector-based models of long-distance dispersal for seeds among isolated oceanic islands based on empirical data. Here, we propose an experimental methodology and present a novel sensor platform to circumvent these limitations and directly estimate a mechanistic, vector-based model of seed dispersal in the ocean.
We have developed seed analogues, or pseudoseeds, outfitted with wireless sensor technology that will enable high-fidelity tracking as they disperse across large distances in the ocean. The pseudoseeds are precisely designed to mimic actual seed buoyancy and morphology enabling realistic and accurate, vector-based dispersal models of ocean seed dispersal over vast geographic scales.
Jen-Ping Peng, National Taiwan Ocean University, Estimation of Occurrence Probability of Oceanic Rogue Waves
Abstract—Freak wave may cause danger to ships or people who active at coastal area. Prediction of freak wave can provide early alarm information and hence reduce risks of hazards. However, due to the unclear of freak wave mechanism, deterministic prediction is not possible but stochastic method can be used for research of occurrence probability of freak waves. In this study, nonlinear wave theory is considered for derivation of freak wave occurrence probability. It is function of number of waves and kurtosis of water elevation. Field data from long-term measurements were used for validation which demonstrates the existence of bias. The average root-mean-square-error is 22.4% which is acceptable.
Ming Zhang, Zhejiang University, A Modular Autonomous Underwater Vehicle for Environment Sampling: System Design and Preliminary Experimental Results
Abstract—A small-size autonomous underwater vehicle (AUV) for underwater environmental sampling is developed. Example applications include bottom mapping using a sidescan sonar, and thermocline tracking using the conductivity-temperature-depth sensor. The AUV has a modular mechanical, electronic and software design which allows for a simple integration of payload sensors selected for different applications. It consists of five sections: three basic sections, one application section, and one optional section. The hardware architecture for the AUV has been designed to achieve a common electrical and mechanical interface between the different sections. The modular software development of the platform is based on the MOOS-IvP architecture. A lake experiment has been performed to test navigation, autopilot and environmental data recording capabilities of the system.
Songsong Zhu, Zhejiang University, Measurement and characterization of wavefront aberration in laser beam propagating over a lake
Abstract—Atmospheric turbulence is a main limiting factor to the application of wireless laser communication in marine environment, which causes intensity variation and wavefront aberration in the laser beam. Characterizing the wavefront aberration of the laser beam is an important step for mitigating the effect of turbulence. In this paper, we focus on measurement and analysis of wavefront aberration in laser beam propagating over a lake with a transmitter-receiver distance of about 70 meters. Information of wavefront of the laser beam is obtained with a Shack-Hartman wavefront sensor. Both the spatial and temporal characteristics of the wavefront aberration in the laser beam have been investigated and characterized.