ABSTRACT Police patrol units need to split their time between performing preventive patrol and being dispatched to serve emergency incidents. In the existing literature, patrol and dispatch decisions are often studied separately. We consider joint optimization of these two decisions to improve police operations efficiency and reduce response time to emergency calls. We propose a novel method for jointly optimizing multi‐agent patrol and dispatch to learn policies yielding rapid response times. Our method treats each patroller as an independent ‐learner (agent) with a shared deep ‐network that represents the state‐action values. The dispatching decisions are chosen using mixed‐integer programming and value function approximation from combinatorial action spaces. We demonstrate that this heterogeneous multi‐agent reinforcement learning approach is capable of learning joint policies that outperform those optimized for patrol or dispatch alone. Policies jointly optimized for patrol and dispatch can lead to more effective service while targeting demonstrably flexible objectives, such as those encouraging efficiency and equity in response.
This article makes a valuable contribution to the emerging field of marine social sciences by focusing on the potential contribution of learning theory and praxes in promoting ocean literacy, marine identity, and marine citizenship. These are advocated as important social dimensions of the changes and outcomes required to promote sustainability and resilience of marine environments and, by extension, terrestrial environments, across a range of scales from local to planetary. This is because the factors that compromise marine resilience are largely anthropogenic, and a consequence of the negative outcomes of human disassociation from the ocean. From another perspective, the article is equally concerned with how to promote personal resilience and ocean stewardship as positive personal and social outcomes exhibited by people, especially young people. A synergy is noted between outdoor adventurous education and inquiry‐based science learning in marine contexts, with sail training being identified as particularly effective as a marine‐oriented experiential learning approach and context. These insights are exemplified through a case study of sail training programmes developed and operated in the UK. Preliminary findings from trainee questionnaires support the contention that sail training is a powerful vehicle for personal growth across the range of learning dimensions (upward, outward, inward, and downward personal growth). Feedback also indicates the development of ocean literacy, marine identity, and marine citizenship amongst some participating trainees which, together, promote personal resilience and a commitment to marine stewardship (advocates of and active agents for promoting ocean sustainability).
With the growing deployment of multi-USV (unmanned surface vehicle) systems for complex maritime operations, coordinated path planning is critical for safety and efficiency in congested waterways. Classical multi-agent path finding (MAPF) methods, however, often neglect vessel kinematics and collision envelopes, yielding trajectories that are impractical or unsafe at sea. We present a centralized planning framework based on any-angle Safe Interval Path Planning (AA-SIPP) augmented with a vessel-specific maximum yaw-rate constraint. This yields smooth, kinematically feasible trajectories while preserving continuous-time separation. The approach is validated in high-fidelity Gazebo marina simulations involving up to 20 USVs based on the WAM-V platform. Compared with Conflict-Based Search (CBS), a representative grid-based MAPF algorithm, our framework maintained the prescribed safety distances and achieved zero collisions across all scenarios considered, whereas CBS exhibited separation violations in simulation. The method also scales well: mission makespan remained nearly constant as fleet size increased. These results support the applicability of dynamically constrained MAPF to maritime coordination in congested environments.
The squat determination during ships movement on restricted water areas is one of the most important problems affecting navigational safety. Precise squat prediction is essential to minimize the risk of grounding for ships. In Poland we have about 60 operated ferry crossing, part of them are base of transport infrastructure. The Lower Vistula River in Poland is a clear example of a shallow river. Zones of active sediment transport of sandy material are big problem in navigation conditions maintenance on this river. The paper presents an analysis of squat phenomena of ferry “Flisak” by empirical method and fluid dynamic in different conditions. The results of this research could be helpful for inland transport management, risk assessment of ferry crossing the Vistula River, and analysis for a new waterway project.
Alessandro Frascati, Michele Bolla Pittaluga, Octavio E. Sequeiros
et al.
Turbidity currents pose significant threats to offshore seabed infrastructures, including subsea hydrocarbon production facilities and submarine communication cables. These powerful underwater flows can damage pipelines, potentially causing hydrocarbon spills that endanger local communities, the environment, and negatively impact energy production infrastructures. Therefore, a comprehensive understanding of the spatio-temporal development and destructive force of turbidity currents is essential. While numerical computation of 3D flow, sediment transport, and substrate exchange is possible, field-scale simulations are computationally intensive. In this study, we develop a simplified morphodynamic approach to model the flow properties of channelized turbidity currents and the associated trends of sediment accretion and erosion. This model is applied to the Baco–Malaylay submarine system to investigate the dynamics of a significant turbidity current event that impacted a submarine pipeline offshore the Philippines. The modeling results align with available seabed assessments and observed erosion trends of the protective rock berm. Our simplified modeling approach shows good agreement with simulations from a fully 3D numerical model, demonstrating its effectiveness in providing valuable insights while reducing computational demands.
Lucia Porlan-Ferrando, J. David Nuñez-Gonzalez, Alain Ulazia Manterola
et al.
Accurate prediction of extreme waves, particularly the maximum wave height and the ratio between the maximum and significant wave heights of individual waves, is crucial for maritime safety and the resilience of offshore infrastructure. This study employs machine learning (ML) techniques such as linear regression modeling (LM), support vector regression (SVR), long short-term memory (LSTM), and gated recurrent units (GRU) to develop predictive models based on historical data (1990–2024) obtained from a buoy at a specific oceanic location. The results show that the SVR model provides the highest accuracy in predicting the maximum wave height (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>H</mi><mrow><mi>m</mi><mi>a</mi><mi>x</mi></mrow></msub></semantics></math></inline-formula>), achieving a coefficient of determination (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>R</mi><mn>2</mn></msup></semantics></math></inline-formula>) of 0.9006 and mean squared error (MSE) of 0.0185. For estimation of the ratio between maximum and significant wave heights (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>H</mi><mrow><mi>m</mi><mi>a</mi><mi>x</mi></mrow></msub><mo>/</mo><msub><mi>H</mi><mi>s</mi></msub></mrow></semantics></math></inline-formula>), the SVR and LM models exhibit comparable performance, with MSE values of 0.0229. These findings have significant implications for improving early warning systems, optimizing the structural design of offshore infrastructure, and enhancing the efficiency of energy extraction under changing climate conditions.
ABSTRACT This paper studies a two‐stage adaptive robust hub location problem with multiple assignments under demand uncertainty. In our setting, the capacitated hubs are strategically located in the first stage to minimize the worst‐case scenario cost over a budgeted uncertainty set, and the routing decisions, which are adaptive to uncertainty realizations, are made in the second stage to transport all commodities. For the large‐scale instances of the problem, we develop a novel column‐and‐constraint generation approach that integrates Benders decomposition. In this approach, we design a customized Benders decomposition to efficiently solve the master problem involving a subset of uncertain scenarios, in which a tailored cutting plane algorithm is developed to solve Benders dual subproblems and a cut refinement strategy is proposed to generate strong Benders cuts. Besides, to quickly identify possible uncertain scenarios, we reformulate the second‐stage problem into a more tractable form, which is further simplified by significantly reducing the number of redundant variables and constraints. Extensive computational experiments on the well‐known instances with up to 200 nodes are conducted to evaluate the effectiveness of proposed model and the performance of the solution method. The computational results demonstrate that our developed solution method outperforms the conventional column‐and‐constraint generation or Benders decomposition. Compared with the two‐stage stochastic programming model, our proposed model can provide more reliable and robust solutions with superior out‐of‐sample performance. The results also illustrate the effect of uncertainty budgets and highlight the advantages of incorporating features such as hub capacity and multiple assignments into our model. Moreover, we make extensions by applying our framework to handle more general polyhedral uncertainty sets.
This study introduces a groundbreaking approach for real-time 3D localization, specifically focusing on achieving seamless and precise localization during the terminal guidance phase of an autonomous underwater vehicle (AUV) as it approaches an omnidirectional docking component in an automated deployable launch and recovery system (LARS). Using the AUV’s magnetometer, an economical electromagnetic beacon embedded in the docking component, and an advanced signal processing algorithm, this novel approach ensures the accurate localization of the docking component in three dimensions without the need for direct line-of-sight contact. The method’s real-time capabilities were rigorously evaluated via simulations, prototype experiments in a controlled lab setting, and extensive full-scale pool experiments. These assessments consistently demonstrated an exceptional average positioning accuracy of under 3 cm, marking a significant advancement in AUV guidance systems.
The vertical eddy viscosity coefficient (VEVC) is an important parameter used in ocean dynamics studies to describe the intensity of mixing in the vertical direction and the process of momentum transport. In this paper, an adjoint assimilation method was used to invert the VEVC, based on the Ekman model, with the measured wind field and current data. The main purpose was to study the effect of changes in the background wind field on VEVC, and thus investigate the role of wind stress in the inversion process. The results indicated that the inverse vertical eddy viscosity coefficient increased slightly at the surface layer, reaching its maximum at around 10–12 m, and then decreased monotonically with depth. The maximum VEVC value corresponds to different depths for different wind speed ranges. Additionally, wind steering could affect the VEVC inversion curve, causing it to deviate from the general trend. The kinetic energy ratio increased with depth, peaked at 18–20 m, and then rapidly decreased to nearly zero beyond 24 m. The impact of wind field strength and steering on VEVC was observed in the kinetic energy ratio curve, which confirms the speculative wind stress effect. This study revealed the characteristics and mechanisms of VEVC in coastal waters under different wind conditions, which could provide a reference for further research on physical oceanography.
Torcuato Pulido Mantas, Camilla Roveta, Barbara Calcinai
et al.
The series of technological advances that occurred over the past two decades allowed photogrammetry-based approaches to achieve their actual potential, giving birth to one of the most popular and applied procedures: structure from motion (SfM). The technique expanded rapidly to different environments, from the early ground-based and aerial applications in terrestrial scenarios, to underground and underwater surveys. Nevertheless, the transfer through different media required a period of adaptation that could take anything from years to decades. Only recently, thanks to the emergence of low-cost versatile imaging systems, have airborne and underwater photogrammetry became approachable to a wide range of research budgets, resulting in a popular cost-effective solution for many disciplines. Although numerous review efforts have already been made to resume the current knowledge on photogrammetry, this review summarizes the evolution of the technique in both terrestrial and underwater environments, paying special attention to the transfer of methods and techniques between the two environments. The acquired information helped to identify trends during its development and to highlight the urgency to widen the range of its applications in aquatic habitats in order to fill the current gap of knowledge on their structure and species distribution, delaying the design of proper conservation strategies.
Catfish is one of the freshwater aquaculture commodities with a high level of consumption and production in Indonesia. Disease outbreaks could occur in catfish farming activities caused by pathogenic bacteria. Several species of pathogenic bacteria can cause disease in catfish, resulting in mass death. This can lead to decrease in the food quality of freshwater fishery products, especially catfish. In cultured system, aquaculture occurrence of diseases can cause severe financial losses. Catfish samples were obtained from catfish farming with clinical symptoms of reddish spots on the outside of the body. Bacteria were isolated from the kidney and liver under aseptic conditions. These bacteria isolates were identified through their colony morphology, Gram staining, biochemical tests, molecular test, and antibacterial test of Bacillus spp. using spot and disc diffusion test. Identification based on 16S rRNA gene showed that GL1 was 99.92% closely related to Aeromonas widowei, HL1 was 100% closely to Bacillus amyloliquefaciens, and GL2 and HL2 was closely related to Bacillus cereus. The antibacterial test results of APD10 isolates of Bacillus velenzensis species inhibited GL2 pathogenic bacteria with an inhibition zone of 22.15 mm in the very strong inhibition zone and HL2 pathogenic bacteria with an inhibition zone of 8.5 mm in the moderate inhibition zone. Bacillus velezensis was isolated from the sponge Aplysina sp. could be further utilized as a biocontrol agent for the pathogenic bacteria, Bacillus cereus, that infects catfish.
Keywords: Catfish, pathogenic bacteria, Bacillus, Aplysina, antibacterial
Carolyn A. Reynolds, William Crawford, Andrew Huang
et al.
Abstract High-fidelity analyses and forecasts of integrated vapor transport (VT) are central to the study of Earth’s hydrological cycle as well as high-impact phenomena such as monsoons and atmospheric rivers. The impact of the in-line analysis correction-based additive inflation (ACAI) on IVT biases and forecast errors is examined within the Navy Earth System Prediction Capability (Navy ESPC) global coupled system. The ACAI technique uses atmospheric analysis corrections from the data assimilation system to approximate model bias and as a representation of stochastic model error to simultaneously reduce systematic and random errors and improve ensemble performance. ACAI reduces the global average magnitude of the 7- and 14-day IVT bias by 16%–17% during Northern Hemisphere summer, reaching 70% reductions in some tropical regions. The global average IVT bias reduction is similar to the bias reduction for low-level wind speed bias and considerably smaller than the bias reduction in total precipitable water. The localized regions where ACAI increases IVT bias occur where the control IVT biases change sign and structure with increasing forecast lead time, such as the South Asian monsoon region. Substituting analyzed wind or moisture fields for the forecast fields when calculating the forecast IVT confirms that, on average, wind errors dominate the IVT error calculation in the tropics, although wind and moisture error contributions are comparable in the extratropics. The existence of regions where using either analyzed winds or analyzed moisture increases IVT bias or mean absolute error reveals areas with compensating errors.
In the present study, breaking focused wave groups were simulated using open-source Computational Fluid Dynamics model REEF3D in order to investigate the breaking wave impact on scaled (1:10) two-dimensional coastal deck structure with girder. The effect of environmental parameters, such as bottom slope and wave steepness on the breaking and geometric properties of high-crested spilling breakers, was investigated. The effect of the wave breaking location on the impact forces acting on the deck structure located at different airgap positions was studied for three wave impact scenarios: (i) when the wave breaking starts, (ii) when a slightly overturning crest is formed, and (iii) when the wave breaks and a fully overturning crest is formed just before hitting the preceding trough. The peak horizontal impact force was found to be higher when the wave breaks ahead of the structure and the overturning wave crest hits the deck positioned above the still water level. Additionally, the peak vertical impact force attains the peak when the deck is placed at the still water level for different stages of breaking. The peak horizontal impact force shows a parabolic trend, whereas the peak vertical impact forces show a decreasing linear trend with an increase in airgap. Finally, force coefficients are derived for calculating the peak impact force on deck with girders subjected to high-crested spilling breakers.
Abstract Using a data sample of $$\sqrt{s}=13\,\text {TeV}$$ s = 13 TeV proton-proton collisions collected by the CMS experiment at the LHC in 2017 and 2018 with an integrated luminosity of $$103\text {~fb}^{-1}$$ 103 fb - 1 , the $$\text {B}^{0}_{\mathrm{s}} \rightarrow \uppsi (\text {2S})\text {K}_\mathrm{S}^{0}$$ B s 0 → ψ ( 2S ) K S 0 and $$\text {B}^{0} \rightarrow \uppsi (\text {2S})\text {K}_\mathrm{S}^{0} \uppi ^+\uppi ^-$$ B 0 → ψ ( 2S ) K S 0 π + π - decays are observed with significances exceeding 5 standard deviations. The resulting branching fraction ratios, measured for the first time, correspond to $${\mathcal {B}}(\text {B}^{0}_{\mathrm{s}} \rightarrow \uppsi (\text {2S})K_\mathrm{S}^{0})/{\mathcal {B}}(\text {B}^{0}\rightarrow \uppsi (\text {2S})K_\mathrm{S}^{0}) = (3.33 \pm 0.69 (\text {stat})\, \pm 0.11\,(\text {syst}) \pm 0.34\,(f_{\mathrm{s}}/f_{\mathrm{d}})) \times 10^{-2}$$ B ( B s 0 → ψ ( 2S ) K S 0 ) / B ( B 0 → ψ ( 2S ) K S 0 ) = ( 3.33 ± 0.69 ( stat ) ± 0.11 ( syst ) ± 0.34 ( f s / f d ) ) × 10 - 2 and $${\mathcal {B}}(\text {B}^{0} \rightarrow \uppsi (\text {2S})\text {K}_\mathrm{S}^{0} \uppi ^{+} \uppi ^{-})/ {\mathcal {B}}(\text {B}^{0} \rightarrow \uppsi (\text {2S})\text {K}^{0}_{\mathrm{S}}) = 0.480 \pm 0.013\,(\text {stat}) \pm 0.032\,(\text {syst})$$ B ( B 0 → ψ ( 2S ) K S 0 π + π - ) / B ( B 0 → ψ ( 2S ) K S 0 ) = 0.480 ± 0.013 ( stat ) ± 0.032 ( syst ) , where the last uncertainty in the first ratio is related to the uncertainty in the ratio of production cross sections of $$\hbox {B}^{0}_{\mathrm{s}}$$ B s 0 and $$\hbox {B}^{0}$$ B 0 mesons, $$f_{\mathrm{s}}/f_{\mathrm{d}}$$ f s / f d .
Astrophysics, Nuclear and particle physics. Atomic energy. Radioactivity
Laurent Grare, Nicholas M. Statom, Nick Pizzo
et al.
Over the last several years, the Air-Sea Interaction Laboratory at Scripps Institution of Oceanography has developed a fleet of wave-powered, uncrewed Wave Gliders (Liquid Robotics) specifically designed and instrumented for state-of-the-art air-sea interaction and upper ocean observations. In this study, measurement capabilities from these platforms are carefully described, compared, and validated against coincident measurements from well-established, independent data sources. Data collected from four major field programs from 2013 to 2020 are considered in the analysis. Case studies focusing on air-sea interaction, Langmuir circulations, and frontal processes are presented. We demonstrate here that these novel, instrumented platforms are capable of collecting observations with minimal flow-structure interaction in the air-sea boundary layer, a region of crucial current and future importance for models of weather and climate.
ZHUO Pengcheng, YAN Jin, ZHENG Meimei, XIA Tangbin, XI Lifeng
For the fault diagnosis needs of the full life cycle (light degradation, moderate degradation, and severe degradation) of rolling bearing under the environment of high background noise, a genetic algorithm-output input hidden feedback (GA-OIHF ) Elman neural network model is proposed to achieve precise diagnosis of the degradation faults of rolling bearing. Ensemble empirical mode decomposition (EEMD) is selected to effectively reduce the noise and extract fault features of the vibration signal. An OIHF Elman neural network is designed by increasing the feedbacks from the output layer to the hidden layer and the input layer based on the Elman neural network, thus further improves its ability to process full life cycle data of rolling bearing. Then, a novel GA-OIHF Elman neural network model is developed by combining the genetic algorithm (GA) and the OIHF Elman neural network. The novel GA-OIHF Elman neural network model combines the global optimization of GA and the local optimization ability of the OIHF Elman neural network to achieve an accurate fault diagnosis of the entire life cycle of rolling bearing. The experimental results show that the GA-OIHF Elman algorithm model can not only accurately diagnose the fault in the full life cycle of rolling bearing, but also ensure the stability of the diagnosis model for different faults including different fault components and stages.
Engineering (General). Civil engineering (General), Chemical engineering
Yachting is quite popular in recent years and it is defined as an “entertainment and vacation industry in the sea.” The yachting industry as parallel to the world economy is developing rapidly in financial, industrial, and physical spaces in the world and in Turkey as well. With this development, yachting provides foreign currency inflow to Turkey in the tourism sector as well as in the construction industry according to the Turkish Statistical Institute’s data. Turkey is greatly known in the European yacht and boat market particularly in terms of engine manufacture and specialization, low labor cost, and quality advantages. This study is aimed to determine a suitable shipyard’s city to carry out a 30-meter motor yacht. In this research study, a model was suggested for selecting the appropriate shipyard for motor-yacht construction with a proposed solution methodology. In the research methodology, 15 criteria were determined for evaluating 4 shipyards that have different properties and are located in different cities of Turkey. In the first phase of the solution, SWARA was used to obtain the importance weights of the criteria. In the second phase of the solution, alternatives were evaluated with COPRAS according to the calculated importance weights. The proposed model and solution methodology were conducted through an explanatory sample.
The physical and mechanical properties of sea ice and the failure modes of ice sheets significantly affect the ice loading of offshore structures. This paper first introduces the physical and mechanical characteristics of sea ice, then describes the physical processes of the interaction of ice sheets with offshore structures. Finally, the progress of research on the ice loading of offshore structures is briefly analyzed, including the three main approaches of formula estimation, experimental testing and numerical simulation. By discussing the applicability of formula estimation, the research focus and difficulties of experimental testing, and the development trends of numerical simulation, we find that the model testing of ice loading is an effective method. This paper covers the research trends and problems faced by ice loading on offshore structures, and it can provide certain guiding references for the related research of scholars in the field.