Shore Station Research Articles

Conversational user interfaces for maritime autonomous surface ships

We propose integrating conversational user interfaces (CUIs) into Maritime Autonomous Surface Ships (MASS) to facilitate direct communication with other ships without human intervention. The aim is to enable other ships and shore stations to inquire about and discuss the autonomous vessel's status, decisions, and future intentions in natural language, offloading VHF radio conversations for MASS operators. Recent advancements in Natural Language Processing (NLP) technology show promise. This paper presents an experimental study conducted in a ship simulator using a functional prototype CUI system. While the CUI system was capable of providing coherent answers to questions, the results indicate that interacting with the system is less trustworthy than interacting with a human ship officer. Key challenges contributing to this included: (1) a missing connection between the CUI and an autonomy system, leading to inaccurate and incorrect answers, (2) speech that lacked intonation and human-like qualities, and (3) a perceived inability of the system to collaborate. The paper discusses several aspects of utilising CUI systems in a maritime shipping environment and concludes by proposing an approach to develop and implement them safely.

Conceptual design of shore station for an innovative waste collecting vessel

Marine environment protection legislation in the EU requires ships to return waste they generate on voyages to waste-reception facilities in ports. In many harbors there is a need to expand the port infrastructure to enable the operation of Waste Collecting Vessels (WCVs). In addition, these vessels can perform new functions of cleaning port basins and adjacent waterways. A novelty in the presented research on the conceptual design of the shore station is the inclusion of new requirements for an autonomy and modularization of the vessel. The shore station was designed in the form of a floating pontoon, taking into account the various functional requirements addressed in the ship's conceptual design stage. The pontoon consists of modules corresponding to the ship segments moored in them. The conceptual design was intentionally defined in a generalized form to allow for further development and adaptation to local requirements at individual ports.

Programmable flow injection: a versatile technique for benchtop and autonomous analysis of phosphate and silicate in seawater

High-resolution, autonomous monitoring of phosphate and silicate in the marine environment is essential to understand their complex dynamics and implications for the functioning of marine ecosystems. In the absence of dependable reagent-less sensors for these nutrients, leveraging established colorimetric techniques using miniaturized analyzers, such as programmable Flow Injection (pFI), offers the best immediate solution to meet oceanographic accuracy and precision standards. In this work, we further optimize the phosphomolybdate and silicomolybdate assays recently adapted for use with pFI, laying the groundwork for the technique’s use for long-term, autonomous operations. For both assays, we show that only a narrow range of acidities and molybdate concentrations can maximize sensitivity while minimizing salt effects. In addition, we demonstrate the stability of our optimized colorimetric reagent formulations, ensuring that analytical sensitivity remains within 10% of initial levels for at least 35 days of continuous use. We then applied our optimized protocols to produce oceanographically consistent phosphate and silicate profiles at the Hawaii Ocean Time Series (HOTS) and Southern Ocean Time Series (SOTS), respectively, which compared favorably against a reference method and historical data. Using certified reference materials for nutrients in seawater, we show that our pFI protocols, optimized for long-term operations, achieve a shipboard precision better than 6% and a relative combined uncertainty (k=1) of 4.5% for phosphate (0.45 - 2.95 µmol L-1) and 6.2% for silicate (2.2 to 103 µmol L-1). To demonstrate pFI’s potential as a versatile tool for autonomous monitoring, we report a five-day hourly phosphate time series at a coastal shore station in central California (n=121 analyses), examine phosphate uptake by seaweed at five-minute intervals at a seaweed aquaculture facility (n=103), and discuss a unique, high-resolution surface silicate transect spanning multiple frontal zones in the Australian sector of the Southern Ocean (n=249). These data, obtained using a commercially available pFI analyzer, confirm that pFI is a viable technology for autonomous monitoring of phosphate and silicate, paving the way for more ambitious, long-term deployments in a variety of settings.

System Architecture and Communication Infrastructure for the RoboVaaS Project

Current advancements in waterborne autonomous systems, together with the development of cloud-based service-oriented architectures and the recent availability of low-cost underwater acoustic modems and long-range above-water wireless devices, enable the development of new applications to support ships and port activities. Autonomous surface vehicles can, for instance, be used to perform bathymetry and environmental data collection tasks to ensure under keel clearance and to monitor the quality of the water. Similarly, remotely operated vehicles can be deployed to inspect ship hulls and typical port infrastructure elements, such as quay and sheet pilling walls. In this article, we present the complete system deployed for the small-scale demonstrations of the Robotic Vessels as-a-Service project, which introduces an on-demand service-based cloud system that dispatches unmanned vehicles capable of performing the required service either autonomously or piloted. These vessels are able to interact with sensors deployed in the port and with the shore station through an integrated underwater and above-water network. The developed system has been validated through sea trials and showcased through an underwater sensor data collection use case. The results of the test presented in this article provide a proof of concept of the system design and indicate its technical feasibility. It also shows the need for further developments for a mature technology allowing on-demand robotic maritime assistance services in real operational scenarios.

Calibration Facility for Detector Strings for the KM3NeT/ARCA Neutrino Telescope at the Capacity Laboratory

KM3NeT is a network of submarine Cherenkov neutrino telescopes under construction at two different sites in the Mediterranean Sea. ARCA, near Sicily in Italy, is optimised for the detection of cosmic neutrinos while ORCA, near Toulon in France, is optimized for atmospheric neutrinos. ARCA and ORCA are both arrays of thousands of optical sensors (Digital Optical Modules - DOMs), each consisting of 31 small photomultipliers (PMTs) housed inside a glass sphere, which detect the Cherenkov light produced by the secondary particles generated in the neutrino interactions. 18 DOMs are arranged on flexible strings, referred to as vertical Detection Units (DUs), anchored to the sea floor. Once completed, ARCA and ORCA will consist of 230 and 115 DUs, respectively. Each DOM of a string communicates at a dedicated wavelength to the shore station via a network of optical fibers transmitting optical and acoustic signal information as well as orientation information. Before the deployment, each DU is tested and calibrated in a dark room. The test bench is equipped with a full data acquisition system for communication, data processing, and time synchronisation. Several steps are needed to accomplish the DU calibration, including the High-Voltage (HV) tuning of the PMTs, checking of the acoustic receivers and calibration light sources in the DOM, and time calibration using laser signals distributed to all DOMs. Here, we describe the DU test and calibration facility at the CAPACITY laboratory (Campania AstroPArtiCle InfrastrucTure facilitY) in Caserta, focusing on the functional tests and calibrations performed at the end of the DU integration.

History of whaling in Trinidad and Tobago

Shore whaling for humpback whales (Megaptera novaeangliae) in Trinidad represents a largely overlooked aspect of North Atlantic whaling history. Literature and archival sources were searched for information on the chronology, nature and extent of this whaling. The first shore station began operations in about 1826 on one of the islands in the Dragon’s Mouth, the strait connecting the southern Caribbean Sea with the Gulf of Paria. At least four stations were active in this area at one time or another and the maximum documented one-year catch was about 35 humpbacks. Whaling effort had begun to decline by the 1850s and was largely ended by the 1880s. Oil for domestic consumption as well as export was the main product. Removals by the shore whalers were in addition to those by American pelagic whalers who occasionally called at Port-of-Spain and whaled in the vicinity of Trinidad and along the Spanish Main. No evidence was found of organised shore whaling in Tobago.

The influence of whalewatching on the behaviour of migrating gray whales (Eschrichtius robustus) in Todos Santos Bay and surrounding waters, Baja California, Mexico

This study investigated the influence of whalewatching boats on the behaviour of gray whales on their migratory route in Todos Santos Bay, near the port of Ensenada, Baja California, Mexico. The objectives were: (1) to compare the swimming direction and velocity of whales in the presence and absence of whalewatching vessels, and when other boats were fishing, cruising or drifting; and (2) to contribute scientific data to the improvement of whalewatching regulations for Todos Santos Bay and surrounding waters. During the winters of 1998 and 1999, theodolite tracking was undertaken from a lighthouse tower located on northern Todos Santos Island. During both years, the migration corridor was about 2.5km wide at the Todos Santos Islands; this is relatively narrow compared to other shore stations along the northern coast (USA). Sightings were separated into northbound or southbound migration routes and the variability of whale swimming direction was analysed by circular statistics. During the southbound migration, whale swimming direction was not different in the presence or absence of whalewatching vessels and other boats. This variable, however, was statistically different during the northbound migration both with whalewatching vessels (p = 0.007) and with other boats (p = 0.02). Whale swimming velocity showed significant differences without boats and with whalewatching boats during both migrations (northbound, p = 0.04; southbound, p < 0.001). Analysis of velocity in the absence and presence of other boats did not yield significant differences for either of the migrations. In addition, a head-on approach by whalewatching boats changed the whales’ swimming direction (p = 0.05) and velocity (p = 0.015) significantly when compared with an approach towards the rear or flanks. Although Mexican whalewatching law is explicit concerning manoeuvres around whale groups, an additional suggestion is made here to prevent unintentional head-on approaches.

Investigation and comparative analysis of ecological risk for heavy metals in sediment and surface water in east coast estuaries of India

The sediments and surface water from 8 stations each from Dhamara and Paradeep estuarine areas were sampled for investigation of heavy metals, Cd, Cu, Pb, Mn, Ni, Zn, Fe, and Cr contamination. The objective of the sediment and surface water characterization is to find the existing spatial and temporal intercorrelation. The sediment accumulation index (Ised), enrichment index (IEn), ecological risk index (IEcR) and probability heavy metals (p-HMI) reveal the contamination status with Mn, Ni, Zn, Cr, and Cu showing permissible (0 ≤ Ised ≤ 1, IEn ˂ 2, IEcR ≤ 150) to moderate (1 ≤ Ised ≤ 2, 40 ≤ Rf ≤ 80) contamination. The p-HMI reflects the range from excellent (p-HMI = 14.89-14.54) to fair (p-HMI = 22.31-26.56) in off shore stations of the estuary. The spatial patterns of the heavy metals load index (IHMc) along the coast lines indicate that the pollution hotspots are progressively divulged to trace metals pollution over time. Heavy metal source analysis coupled with correlation analysis and principal component analysis (PCA) was used as a data reduction technique, which reveals that the heavy metal pollution in marine coastline might originate from redox reactions (FeMn coupling) and anthropogenic sources.

Whale catches from 19th century shore stations in Western Australia

This paper presents historical data from 19th century shore whaling stations along the Western Australian coast, complementing data already presented in an earlier 1985 analysis. In particular, catch records of the Castle Rock whaling station, Geographe Bay, Western Australia, for the period 1846–53 together with other contemporary records indicate that humpback whales (Megaptera novaeangliae) comprised the majority of the colonial shore whalers’ catch. It is suggested that this could have been a result of a significant presence of American whale ships in the region in the early 1840s, which had presumably already reduced southern right whale (Eubalaena australis) numbers by the time these detailed colonial records were kept.

An integrated monitoring system for disaster-causing organisms in the water intake areas of coastal nuclear power plants

Nowadays, nuclear power plays an important role in the energy structure of many countries. However, A bloom of a disaster-causing organism (DCO) in the cold-water intake area of a coastal nuclear power plant can block the water cooling system and seriously affect the operational safety of the nuclear power unit. Currently, the traditional method of protection is to estimate the DCO abundance by regular manual investigation and sampling, but that method cannot give continuous real-time data. Instead, proposed and implemented here is a seafloor in situ integrated monitoring system for DCOs (known as IMSDCO), which is equipped with an optical microscopic imager (OMI) and hydrometric sensors to monitor automatically the DCO abundance and hydrology. All the data are transmitted to a terminal in the shore station through a photoelectric composite cable for real-time display. When the DCO abundance reaches a preset threshold, software automatically raises an alarm. Since placing IMSDCO at the cold-water intake of the Changjiang nuclear power plant, a six-month field trial has been completed, during which large amounts of hydrology data and DCO images were obtained. IMSDCO successfully identified and estimated the abundances of various DCOs (e.g., Phaeocystis globosa, Acetes chinensis, and small fish) and predicted their movements based on hydrology data. Based on the analysis of the experimental data, we discussed the reasons for the error in the abundance estimation of DCO and the methods to reduce the error. The experimental results show that the OMI-based IMSDCO can monitor and give early warning of DCOs in the water intake areas of costal nuclear power plants and is worthy of long-term deployment.

Diversity and Life-Cycle Analysis of Pacific Ocean Zooplankton by Videomicroscopy and DNA Barcoding: Gastropods

The life cycles and biodiversity of Pacific coast gastropods were analyzed by videomicroscopy and DNA barcoding of individuals collected from tide pools and in plankton nets from a variety of shore stations. In many species (Families Calyptraeidae, Cerithiopsidae, Strombidae, Vermetidae, Columbellidae, Nassariidae, Olivellidae, Hermaeidae, Onchidorididae, Gastropteridae, Haminoeidae), the free-swimming veligers were recovered from plankton collections; in Roperia poulsoni (family Muricidae) veligers were usually recovered from egg sacs where they had been retained although some escapees were found in plankton collections; in Pteropurpura festiva (family Muricidae) free-living veligers were also found; and in Atlanta californiensis (family Atlantidae) both veligers and adults were obtained from plankton collections making this a holoplanktonic species. The results confirm that DNA barcoding based on COI gene sequencing is a useful strategy to match life-cycle stages within species as well as to identify species and to document the level of biodiversity within the gastropods.

Effect of secondary treatment at the South Bay Ocean Outfall (SBOO) on microbial ocean water quality near the US-Mexico border.

In this study, density plume visualizations and statistical comparisons were made of enterococci bacteria (the main marine recreational microbial water quality indicator) densities, both before and after the upgrade of the discharge from the South Bay Ocean Outfall (SBOO) to secondary treatment level, so that the effect of this upgrade on ocean microbial water quality could be assessed. During the dry weather (bathing) season, reduction in enterococci densities was rather limited with only 2 shore stations and one kelp station showing significant reductions, and none showing increased compliance frequency. During the wet weather season, although the signature of land-based sources of bacterial pollution were evident, a majority of both shore (7 of the 11 stations) and kelp (4 of the 7 stations) stations showed statistically significant (p≤0.05) reductions enterococci densities pointing to the role of the upgrade to secondary treatment in improving microbial water quality.

Real-time acoustic monitoring with telemetry to mitigate potential effects of seismic survey sounds on marine mammals: a case study offshore Sakhalin Island

Exxon Neftegas Ltd. (ENL) carried out three 4D seismic surveys during the summer of 2015. Seismic operations in two of these fields (Odoptu and Chayvo) ensonified the nearshore feeding area of Korean-Okhotsk (western) gray whales (Eschrichtius robustus), potentially disturbing feeding activities. Following model-based optimization of the source design to minimize its lateral acoustic footprint, pre-season modeling was used to compute the acoustic exposure along each survey line. Real-time acoustic data facilitated implementation of mitigation measures aimed to minimize disturbance of whales. Acoustic data originated from underwater recorders deployed on the seafloor. Two complementary approaches were used to transmit recorded sound data to a computer housed at the Central Post (CP), where decisions regarding mitigation shut downs were made. In the first approach, a limited bandwidth (2–2000 Hz) sampling of the data was transmitted via cable to a surface buoy, which relayed these data to a shore station up to 15 km away via digital VHF telemetry. At the shore station, acoustic impulses from the seismic surveys were processed to compute impulse characteristics in the form of estimates of sound exposure level and peak sound pressure level, as well as one-minute-average 1/3-octave power spectral density coefficients, which were then transmitted to the CP via the internet. In the second, the pulse characteristics were computed through algorithms running on an onboard processor in each recorder’s surface buoy and sent directly to the CP computer via an Iridium satellite uplink. Both methods of data transfer proved viable, but Iridium transmission achieved the goal without the need for any shore based relay stations and is therefore more operationally efficient than VHF transmission. At the CP, analysts used the real-time acoustic data to calibrate and adjust the output of pre-season acoustical model runs. The acoustic footprint for the active seismic source, advancing synchronously with the motion of the seismic vessel and changing as the sound propagation environment changed, was computed from the calibrated and adjusted model output and integrated through the software Pythagoras with locations of gray whales provided by shore-based observers. This enabled analysts to require air gun array shutdowns before whales were exposed to mean square sound pressure levels greater than the behavioral response threshold of 163 dB re 1 μPa2. The method described here provides a realistic means of mitigating the possible effects of air guns at a behavioral response level, whereas most seismic surveys rely on pre-established mitigation radii to manage the risk of injury to a whale.

Horizontal and vertical segregation of polycyclic aromatic hydrocarbons in the Egyptian Mediterranean coast.

Egyptian Mediterranean coast receives significant amounts of polycyclic aromatic hydrocarbons (PAHs) from industrial exhausts, riverine inputs, maritime shipping and fishers, and oil and natural gas production and exploration. The present study considers the first exhaustive assessment for the dissolved PAHs along the Egyptian Mediterranean coast (Alexandria to Manzallah) to monitor their spatial distribution and investigate the effect of the marine currents and the role of microorganisms in their distribution. Surface water levels ranged between 124.97 and 301.02ng L-1 with an average 223.68 ± 41.11ng L-1. The distribution increases from west to east based on the water circulation in the Mediterranean Sea. The levels in near shore stations were lower than those of middle and onshore stations. The intensive existence of micro-organisms near shore stations consumes great part of PAHs, while this bio-remediation process decreases gradually away from the shoreline leaving relative high concentrations of dissolved PAHs in the middle and onshore stations. Middle and deep-water levels ranged between 312.75 and 1042.95ng L-1 with an average 633.47 ± 225.53ng L-1. Deeper waters showed higher PAHs concentrations where the average concentrations of 50m stations (868.12 ± 138.35ng L-1) ˃ 30m stations (629.49 ± 143.85ng L-1) ˃ 10m stations (402.79 ± 59.46ng L-1). The wind-induced waves re-suspend rich PAHs sediment particles to increase its concentration in the water column. Carcinogenic toxic equivalent quotient (TEQ) for total detected PAHs in the middle and deep water represented more than double (75.46ng TEQ L-1) the value in the surface water (34.76ng TEQ L-1). The diagnostic ratios and principal component analysis indicated mainly pyrogenic origin in surface, middle, and deep waters.

Distribution and abundance of dinoflagellates from the coastal waters of Karachi, Pakistan, northern part of the Arabian Sea.

The present study reports on seasonal and spatial variations in diversity, distribution and abundance of dinoflegellates and indicates the presence of HAB species in Pakistan waters. A total of 179 taxa, recorded in this study from offshore and near-shore waters, belong to 41 genera in 26 families and 10 orders. The high species count (149 species) was recorded from Manora Island offshore station (MI-1) and 105 spp, 109 spp and 115 spp were encountered from the Mubarak village offshore station (MV-1), Manora near shore station (MI-2) and Mubarak Village near-shore station (MV-2) respectively. Tripos furca was the dominant and frequently occurring species (> 1 x103 to > 25 x103 cells L-1 from coastal and >1x 105 cells L-l from near-shore stations) in addition to less abundant Alexandrium catenella, Alexandrium sp., Alexandrium minutum, and Prorocentrum micans (>103 to 25x 103cells/L). Another 44 species occurred in relatively low numbers (<103 cell L-l). Seventy species were found throughout the study period at all four stations. High number of species in three genera (Tripos (38), Protoperidinium (34) and Prorocentrum (20) was recorded. Potently toxic (16 genera 43 species) and HAB related (19 genera and 30 species) dinoflagellate taxa were also recorded. The percent contribution of dinoflagellates in total phytoplankton population generally remained below 20% except for a few instances. Manora Island stations had comparatively higher Shannon index and equitability and slightly lower dominance index. The PCA plot showed strong positive correlation among chlorophyll-a concentration, dissolved oxygen, total number of phytoplankton and dinoflagellates.

Channel Distribution and Noise Characteristics of Distributed Acoustic Sensing Underwater Communications

Due to the power and transmission rate limitations, it is challenging to achieve underwater acoustic (UWA) communications over long distances from the unmanned underwater vehicle (UUV) to the shore station. As an alternative solution, the distributed acoustic sensing (DAS) underwater communication uses submarine optical cable to acquire and demodulate acoustic communication signals. There is little research on the channel and noise of DAS underwater communication. This paper analyzes the channel characteristics and the background noise of a DAS underwater communication system with armored optical cable based on the experimental measurements. Channel analysis shows that the envelope amplitudes of impulse responses follow the Burr distribution. The amplitudes get increased concentration at lower values as the sound source goes closer to the position right above the optical cable. Moreover, we observe that the received signals are influenced by the adjacent segments, leading to multiple arrivals within each acoustic bounce. Noise analysis shows that for frequencies lower than 1 kHz, unlike the Wenz noise spectrum primarily caused by shipping and wind, the −18 dB/octave decrease in power spectral density (PSD) of DAS noise is mainly caused by the equipment and cable themselves. The noise also exhibits full-band fluctuations. In underwater communications, full-band noise poses significant challenges for signal design. As far as we know, this article is the first report on the field experiment using a DAS underwater communication system equipped with armored optical cable, providing a reference for future underwater applications.

Design of deep-sea chemical data collector for the seafloor observatory network

This paper describes the design of a deep-sea chemical data collector for a seafloor observatory network. The control system of the data collector comprises the main control unit, energy supply distribution unit, serial port expansion unit, condition monitoring, power supply switching unit, and communication unit. The functions of the data collector include self-inspection, diagnosis, and isolation. It also transmits the collected data and the monitoring data in the data collector cabin to the shore station management system in real-time. The data is transmitted through the secondary junction box and the photoelectric composite cable. The data collector also includes optical dissolved oxygen, deep-sea methane, chlorophyll, turbidity, and colored dissolved organic matter (CDOM) sensors. In January 2017, the data collector integrated with domestic chemical sensors was used for the sea trial, in Jiaozhou Bay, Qingdao. The experimental results demonstrate the reliability of the system and the data quality of all chemical parameters.

Stability and Reliability of Small Shore Station Technology in Automatic Water Quality Monitoring

Stability and Reliability of Small Shore Station Technology in Automatic Water Quality Monitoring

Phytoplankton community structure in relation to physico-chemical factors in a tropical soda lake, Lake Shala (Ethiopia)

Phytoplankton communities responses to physico-chemical factors were studied in Lake Shala from January to December 2018. Distinct spatial and seasonal variations were observed for all physico-chemical parameters, except DO (ANOVA: p < 0.05). In total, 72 taxa, Bacillariophyta (55 taxa), Chlorophyta (seven taxa), Cyanobacteria (six taxa), Euglenophyta (two taxa), Dinophyta (one taxon) and Charophyta (one taxon) were identified. Phytoplankton abundance and biomass ranged from 5 789.3 cells ml–1 to 1 516.2 cells ml–1, with a mean of 8 756.9 cells ml–1 and 9.8 μg l−1 to 25.8 μg l−1, with a mean of 17.1 μg l−1, respectively, and showed seasonal variations (p < 0.05). Based on RDA analysis, most species were abundant in Shala Gike Shore station. Their distribution was negatively correlated with salinity and EC, whereas pH, alkalinity, NO3–N, SRP, TP, NH3–N and SiO2 had a positive correlation. Previously Lake Shala was dominated by Cryptophyta but this has switched to a diatom-dominant community. Such changes in phytoplankton taxa may be suggestive of ecological change. This study provides baseline data on the phytoplankton community structure of Lake Shala associated with physico-chemical changes, against which future community structure can be evaluated.

Steering model identification and control design of autonomous ship: a complete experimental study

ABSTRACT Steering ship models are important for the study of autonomous ship manoeuverability and design of ship motion control system. It is always a difficult task to find the mathematical model by first principle as it needs prior knowledge of hydrodynamic derivatives. The input–output-based system identification theory can be used to establish system mathematical models. A solution is offered by developing a Wi-Fi-based self-propelled, autonomous system for a ship model with Internet of Things (IoT) capabilities to perform manoeuvering and seakeeping tests in indoor environment without any complex mechanical structure, viz. following bridge. The developed autonomous on-board system equipped with main computer, suitable electronics, sensors, data acquisition system and Wi-Fi-based communication system. The developed system offers a cost effective, modular and portable solution to perform hydrodynamic studies of different hull form without incorporating major changes in the system. The use of IoT makes the data accessible to a naval architecture in real-time to analyse the motion response of the ship in different wave conditions and enables to implement the digital twin to simulate the real field scenario. Input–output-based model identification experiments such as turning circle and zig-zag tests are conducted to estimate the first-order steering model parameters and is further extended to design and implementation of a classical proportional–derivative-based steering control. The design is described in this paper with details of implementation on a demonstration oceanographic coastal research vessel. It illustrates the excellent communication between shore station computer and the on-board system on a wire-free model with robust control and exhibiting all the motion behaviour and dynamic effects. Experiments performed in wave basin in different wave conditions validate the efficacy of the proffered method.