Beamforming Design for IRS-and-UAV-Aided Two-Way Amplify-and-Forward Relay Networks in Maritime IoT

In this paper,an intelligent reflecting surface(IRS)-and-unmanned aerial vehicle(UAV)-assisted two-way amplify-and-forward(AF)relay network in maritime Internet of Things(IoT)is proposed,where ship1(S1)and ship2(S2)can be viewed as data collecting centers.To enhance the message exchange rate between S1 and S2,a problem of maximizing minimum rate is cast,where the variables,namely AF relay beamforming matrix and IRS phase shifts of two time slots,need to be optimized.To achieve a maximum rate,a low-complexity alternately iterative(AI)scheme based on zero forcing and successive convex approximation(LC-ZF-SCA)algorithm is presented.To obtain a significant rate enhancement,a high-performance AI method based on one step,semidefinite programming and penalty SCA(ONSSDP-PSCA)is proposed.Simulation results show that by the proposed LC-ZF-SCA and ONS-SDP-PSCA methods,the rate of the IRS-and-UAV-assisted AF relay network surpass those of with random phase and only AF relay networks.Moreover,ONS-SDP-PSCA perform better than LC-ZF-SCA in aspect of rate.

GraphSTGAN:Situation understanding network of slow-fast high maneuvering targets for maritime monitor services of IoT data

With the rapid growth of the maritime Internet of Things(IoT)devices for Maritime Monitor Services(MMS),maritime traffic controllers could not handle a massive amount of data in time.For unmanned MMS,one of the key technologies is situation understanding.However,the presence of slow-fast high maneuvering targets and track breakages due to radar blind zones make modeling the dynamics of marine multi-agents difficult,and pose significant challenges to maritime situation understanding.In order to comprehend the situation accurately and thus offer unmanned MMS,it is crucial to model the complex dynamics of multi-agents using IoT big data.Nevertheless,previous methods typically rely on complex assumptions,are plagued by unstructured data,and disregard the interactions between multiple agents and the spatial-temporal correlations.A deep learning model,Graph Spatial-Temporal Generative Adversarial Network(GraphSTGAN),is proposed in this paper,which uses graph neural network to model unstructured data and uses STGAN to learn the spatial-temporal dependencies and interactions.Extensive experiments show the effectiveness and robustness of the proposed method.

Three-dimensional thermohaline structure estimation derived from HY-2 satellite data over the Maritime Silk Road and its applications

Estimated ocean subsurface fields derived from satellite observations provide potential data sources for operational marine environmental monitoring and prediction systems.This study employs a statistic regression reconstruction method,in combination with domestic autonomous sea surface height and sea surface temperature observations from the Haiyang-2(HY-2)satellite fusion data,to establish an operational quasi-realtime three-dimensional(3D)temperature and salinity products over the Maritime Silk Road.These products feature a daily temporal resolution and a spatial resolution of 0.25°×0.25°and exhibit stability and continuity.We have demonstrated the accuracy of the reconstructed thermohaline fields in capturing the 3D thermohaline variations through comprehensive statistical evaluations,after comparing them against Argo observations and ocean analysis data from 2022.The results illustrate that the reconstructed fields effectively represent seasonal variations in oceanic subsurface structures,along with structural changes resulting from mesoscale processes,and the upper ocean’s responses to tropical cyclones.Furthermore,the incorporation of HY-2 satellite observations notably enhances the accuracy of temperature and salinity reconstructions in the Northwest Pacific Ocean and marginally improves salinity reconstruction accuracy in the North Indian Ocean when compared to the World Ocean Atlas 2018 monthly climatology thermohaline fields.As a result,the reconstructed product holds promise for providing quasi-real-time 3D temperature and salinity field information to facilitate fast decisionmaking during emergencies,and also offers foundational thermohaline fields for operational ocean reanalysis and forecasting systems.These contributions enhance the safety and stability of ocean subsurface activities and navigation.

China's Maritime Governance:Practical Evolution and Theoretical Construction

Increasingly engaged in maritime governance,China has developed its distinct vision and gradually established a complete theoretical system surrounding it.In terms of discourse,China has proposed a collection of concepts and ideas including a maritime community with a shared future,the 2lst Century Maritime Silk Road,Blue Partnerships,and marine ecological civilization.In terms of connotations,China champions such values as lasting peace,common prosperity,openness and inclusiveness,and cleanness and beautifulness.Exteriorly and interiorly,we can observe the unique character of China's vision concerning maritime governance,which will continue to upgrade and bear fruit in future practices,boosting the development of Chinese maritime governance theories,multilateral maritime cooperation,and ocean-related international legislation.Guided by its vision,China is expected to contribute more to global maritime security and marine ecological civilization.

Study on the Protection of Sites of“Maritime Silk Road”in Haikou from the Perspective of World Cultural Heritage

The sites of Maritime Silk Road in Haikou City are composed of sites of navigation and trade,religious temples and stone monuments,urban construction and coastal defense scattered on the south bank of the Qiongzhou Strait.They played a key role in the formation and shaping of the settlements in Haikou City,recorded the process of intercommunication and integration between Chinese civilization and other regional cultures,and witnessed the germination,flourishing and inheritance of Haikou’s unique marine culture.The mixture of points,lines and planes blends with the urban area and coastline of Haikou City in spatial distribution.In this paper,from the perspective of world cultural heritage,some suggestions for the protection planning of sites of Maritime Silk Road in Haikou City were proposed based on the analysis of historical and geographical background,comparison of domestic and foreign similar sites,and evaluation of cultural heritage value.

TRADE DEPENDENCIES AND TRANSACTION COSTS: THE OC-CUPATION OF DECELEA HIGHLIGHTS BOTH THE BENEFITS AND THE DRAWBACKS OF A MARITIME ECONOMY

Thucydides asserts that the occupation of Decelea by the Spartans in 413 BC made the grain supply for Athens costly by forcing the transport from land onto the sea.This calls into question the well-established consensus that sea transport was far cheaper than land transport.This paper contends that the cost of protecting supply lines-specifically the expenses associated with the warships which escorted the supply ships-rendered the grain transported on the new route exceptionally costly.In this paper,the benefits and drawbacks of a maritime economy,including transaction costs,trade dependencies,and the capabilities of warships and supply ships are discussed.

Structural Design Study of Air-Dropped Unmanned Maritime Mobile Search and Rescue Platforms

In order to improve the efficiency and safety of search and rescue(SAR)at sea,this paper proposes a kind of emergency rapid rescue unmanned craft(air-dropped unmanned maritime motorized search and rescue platform)that can be delivered by a large transport aircraft.This paper studies the structural design scheme of the platform,and the main scale of the platform,the choice of power system and the impact resistance performance are considered in the design process to ensure its rapid response and effective rescue capability under complex sea conditions.Simulation results show that the platform can withstand the impact of air injection into the water and the shipboard equipment can operate normally under the impact load,thus verifying the feasibility and safety of the design.This study serves to improve the maritime search and rescue system and enhance the oceanic emergency response capability.

Fairness-Oriented Hybrid Precoding for Massive MIMO Maritime Downlink Systems with Large-Scale CSIT

Different from conventional cellular networks, a maritime communication base station(BS) has to cover a much wider area due to the limitation of available BS sites. Accordingly the performance of users far away from the BS is poor in general. This renders the fairness among users a challenging issue for maritime communications. In this paper, we consider a practical massive MIMO maritime BS with hybrid digital and analog precoding. Only the large-scale channel state information at the transmitter(CSIT) is considered so as to reduce the implementation complexity and overhead of the system. On this basis, we address the problem of fairness-oriented precoding design. A max-min optimization problem is formulated and solved in an iterative way. Simulation results demonstrate that the proposed scheme performs much better than conventional hybrid precoding algorithms in terms of minimum achievable rate of all the users, for the typical three-ray maritime channel model.

Environmental Information-Aided Electromagnetic Propagation Testbed for Maritime Communication

Maritime channel modeling can be affected by some key time-varying environmental factors.The ducting effect is one of the thorniest factors since it causes anomalous propagation enhancement and severe co-channel interference.Moreover,the atmospheric attenuation is much more severe in the ocean environment,resulting in shorter coverage distance and more link outage.In this paper,we propose an environmental information-aided electromagnetic propagation testbed.It is based on complex refractivity estimation and improved parabolic equation propagation model,taking into account both ducting effect and atmospheric attenuation.A large-scale temporal and spatial propagation measurement was conducted with meteorological acquisition.We consider practical path loss and ducting conditions to verify the testbed feasibility in these long-distance radio links.The simulation results are in good agreement with the measured data,which further reveal the basic temporal and spatial distribution of ducting effect at 3.5 GHz band.

Towards reinforcement learning in UAV relay for anti-jamming maritime communications

Maritime communications with sea surface reflections and sea wave occlusions are susceptible to jamming attacks due to the wide geographical area and intensive wireless communication services.Unmanned Aerial Vehicles(UAVs)help relay messages to improve communication performance,but the relay policy that depends on the rapidly changing maritime environments is difficult to optimize.In this paper,a reinforcement learning-based UAV relay policy for maritime communications is proposed to resist jamming attacks.Based on previous transmission performance,the relay location,the received power of the transmitted signal and the received jamming power,this scheme optimizes the UAV trajectory and relay power to save the energy consumption and decrease the Bit-Error-Rate(BER)of the maritime signals.A deep reinforcement learning-based scheme is also proposed,which designs a deep neural network with dueling architecture to further improve the communication performance and computational complexity.The performance bounds regarding the signal to interference plus noise ratio,energy consumption and the communication utility are provided based on the Nash equilibrium of the game against jamming,and the computational complexity of the proposed schemes is analyzed.Simulation results show that the proposed schemes improve the energy efficiency and decrease the BER compared with the benchmark.

The Struggle for Atlantic Maritime Security and Safety:Lessons From Africa’s Maritime Security Governance

The enormous economic potentials of the blue/ocean economy have made the maritime domain increasingly susceptible to transnational organized crime and a theater for great power competition,particularly in the Atlantic maritime domain.The maritime security threats are more prevalent in the Atlantic African maritime domain than in other continents.These threats are becoming increasingly detrimental to the African security,safety,and human security,particularly in the coastal countries of the Atlantic Africa.Despite its increasing susceptibility to maritime security threats including great powers competition and the presence of non-Atlantic great powers more than in other maritime domains in Africa,the coastal countries of the Atlantic Sub-Saharan Africa(SSA)have managed to forge strategic inter-regional maritime security partnership that has relatively improved maritime security and safety in the region.There is a growing interest in forging inter-continental partnership of the coastal Atlantic states to collectively respond and address the shared maritime security threats in the entire Atlantic maritime domain.Yet,the way such a complex multilateral partnership would be structured and operationalized has not been worked out.This article assesses the economic potentials,susceptibility to maritime security threats,and level of response to maritime security threats by the coastal countries of the Atlantic SSA with the aim of identifying some lessons that could be relevant for forging the Atlantic inter-continental maritime security partnership.Some of these lessons include genuine partnership that is based on sovereign equality and inter-dependence,a code of conduct,cooperation,and coordination framework,and shared common value system of democratic governance.

Decarbonizing in Maritime Transportation: Challenges and Opportunities

As global warming caused by greenhouse gases grows (GHGs) into a global environmental threat, carbon dioxide emissions are drawing increasing attention in these years. Among all emission sources, transportation is a major contributor to climate change because of its high dependence on fossil fuels. The International Maritime Organization (IMO) has therefore been promoting the reduction of fuel usage and carbon emissions for container ships by such measures as improving shipping route selection, shipping speed optimization, and constructing clean energy propulsion systems. In this paper, a review of the impact of carbon dioxide emissions on climate change is presented;the current situations of carbon dioxide emissions, decarbonizing methods, IMO regulations, and possible future directions of decarbonizing in the maritime transportation industry are also discussed. Based on the result, it is found that in the case that non intelligent ships still occupy the vast majority of operating ships, the use of new energy as the main propulsion fuel has the defects of high renewal cost and long effective period. It is more likely to achieve energy conservation and emission reduction in the shipping industry in a short period of time by using intelligent means and artificial intelligence to assist ship operation. .

Revisiting The Maritime Silk Road In Penglai

Penglai,Yantai City,is located at the northern tip of the Shandong Peninsula,330 kilometers north of Langya Port in Qingdao.In 133 BC,Emperor Wudi(156-87 BC)of the Han Dynasty visited the region during an inspection tour of the eastern part of his empire.He gazed out into the sea in the direction of the mythical Mount Penglai,home of immortals.

The Role of Chittagong Port Authority to Develop Other National Ports in Bangladesh to Provide Maritime Logistics Support in South Asia

Chittagong Port is the principal seaport in Bangladesh that has contributed to the national economy with the opportunity to be a world-class regional port in South Asia.Cooperation among the three national ports Chittagong,Mongla and Payra is essential to do maritime logistics business in the region after serving the nation proudly.Here,Chittagong Port Authority(CPA)has the opportunity to help others in the process of port development for increasing efficiency and productivity by providing financial and technical assistance because of its financial and technical capabilities as a pioneer seaport in the port world.This paper examines the role of CPA to bolster and develop the underutilized Mongla Port and newly established Payra Port,where qualitative research methodology is applied to explore the ways,by which CPA can assist,link and integrate with others effectively,especially in developing the port infrastructure and inland transport networks.In addition,the research found the prospectus of Mongla and Payra to supply port services to the neighbors India,Nepal,and Bhutan as well as serve the South-West part of China with the aim of increasing regional connectivity and promoting international trade in those basically landlocked areas and countries of Asia.

Development of Maritime Mix-Type Structures

Mixed-type structures combining the advantages of pile constructions(low material consumption and possibility to erect on weak soils)and gravity walls(high bearing capacity and stability,good reliability and durability)are considered and improved.The sphere of application,main peculiarities,and practical technological aspects of these structures’implementation are analyzed.

Workshop “Navigating the Transition: Standards Powering the Journey of Alternative Fuel Infrastructure”

April 18, Brussels, Belgium In light of recent significant regulatory changes within the European Union impacting the transport sector, such as the Alternative Fuels Infrastructure Regulation(AFIR), Re Fuel EU and Fuel EU Maritime, the role of European standardization becomes increasingly critical in facilitating the transition towards the deployment of alternative fuels.

Cross-cultural Communicative Competence Training in Maritime Spoken English Teaching

As a means of communication,English has been internationalized.Communication in English always happens among the seafarers from different cultures.If crews couldn’t deal with the cultural differences well,successful communication and shipboard safety,which are just what STCW (Standards on Training,Certificate and Watch -keeping) calls upon,are difficult to be arrived at. Therefore cross -cultural communicative competence training,or how to teach maritime spoken English is the problem or the challenge that we,English teachers,are facing.To show how the teaching can be made more efficient and practical so as to narrow the gap between the training of the seaman in China and the requirements of STCW,through the teaching process,including the syllabus design and the materials selecting,we must consider the notion of language function as the key point.

基于ArcGIS for Maritime的海事测绘信息数据库构建

针对海事测绘信息数据的特点建立统一的数据库,对数据进行规范的组织、存储和管理是海事测绘信息数据服务海洋发展的关键环节。本文归纳了海事测绘信息数据的常见类型,针对各类数据提出了数据库构建方案,以海事测绘部门数据集为基础,进行了海事测绘信息建库的实践,为实现海事测绘的信息化、智能化和规范化服务探索了一条新的途径。

Deep Reinforcement Learning Based Joint Edge Resource Management in Maritime Network

Due to the rapid development of the maritime networks, there has been a growing demand for computation-intensive applications which have various energy consumption, transmission bandwidth and computing latency requirements. Mobile edge computing(MEC) can efficiently minimize computational latency by offloading computation tasks by the terrestrial access network. In this work, we introduce a space-air-ground-sea integrated network architecture with edge and cloud computing components to provide flexible hybrid computing service for maritime service. In the integrated network, satellites and unmanned aerial vehicles(UAVs) provide the users with edge computing services and network access. Based on the architecture, the joint communication and computation resource allocation problem is modelled as a complex decision process, and a deep reinforcement learning based solution is designed to solve the complex optimization problem. Finally, numerical results verify that the proposed approach can improve the communication and computing efficiency greatly.

Placement Optimization of Caching UAV-Assisted Mobile Relay Maritime Communication

Recently, due to the deployment flexibility of unmanned aerial vehicles(UAVs), UAV-assisted mobile relay communication system has been widely used in the maritime communication. However, the performance of UAV-assisted mobile relay communication system is limited by the capacity of wireless backhaul link between base station and UAV. In this paper, we consider a caching UAV-assisted decode-and-forward relay communication system in a downlink maritime communication. For the general case with multiple users, the optimal placement of UAV is obtained by solving the average achievable rate maximization problem through the one-dimensional linear search. For a special case with single user, we derive a semi closedform expression of the optimal placement of UAV. Simulation results confirm the accuracy of analytical results and show that the optimal placement of UAV and the average achievable rate significantly depend on the cache capacity at UAV. We also show the difference between the performances of the air-to-ground model and the air-to-sea model.