Navigation Conditions Research Articles

Robust Autonomous Vehicle Computer-Vision-Based Localization in Challenging Environmental Conditions

In this paper, we present a novel autonomous vehicle (AV) localization design and its implementation, which we recommend to employ in challenging navigation conditions with a poor quality of the satellite navigation system signals and computer vision images. In the case when the GPS signal becomes unstable, other auxiliary navigation systems, such as computer-vision-based positioning, are employed for more accurate localization and mapping. However, the quality of data obtained from AV’s sensors might be deteriorated by the extreme environmental conditions too, which infinitely leads to the decrease in navigation performance. To verify our computer-vision-based localization system design, we considered the Arctic region use case, which poses additional challenges for the AV’s navigation and might employ artificial visual landmarks for improving the localization quality, which we used for the computer vision training. We further enhanced our data by applying affine transformations to increase its diversity. We selected YOLOv4 image detection architecture for our system design, as it demonstrated the highest performance in our experiments. For the computational platform, we employed a Nvidia Jetson AGX Xavier device, as it is well known and widely used in robotic and AV computer vision, as well as deep learning applications. Our empirical study showed that the proposed computer vision system that was further trained on the dataset enhanced by affine transformations became robust regarding image quality degradation caused by extreme environmental conditions. It was effectively able to detect and recognize images of artificial visual landmarks captured in the extreme Arctic region’s conditions. The developed system can be integrated into vehicle navigation facilities to improve their effectiveness and efficiency and to prevent possible navigation performance deterioration.

МОДЕЛЮВАННЯ ДИНАМІЧНИХ ПРОЦЕСІВ ДОВКІЛЛЯ ПІД ЧАС РУХУ СУДНА З ВИКОРИСТАННЯМ РІС ТЕХНОЛОГІЙ

Remote methods of Earth’s surface research have become widely used in the 21st century, as they allow for a larger and more comprehensive observation area. These methods can provide valuable information about various Earth objects and phenomena, such as the changes in bottom topography in shallow water under navigation conditions. This article presents a novel approach to forecasting these changes by using natural processes as indicators and developing programs that can track and display them on electronic devices. The article introduces the concept of “scale factor” to determine the significance of different dynamic processes for the research, depending on their spatial and temporal dimensions. The article also proposes a dynamic map modelling method that can predict the siltation of the sea/river bottom for a given period of time and improve the model by comparing the forecast with the actual result. The article suggests that research should take into account the changes in the object over time and under the influence of various factors in a dynamic way. Based on the research, we draw the following conclusions: 1. The “scale factor” should be applied in dynamic navigation map research and compilation using different-scale data of the water surface and bottom topography; 2. A dynamic component should be added to the information block of the navigation cartographic systems ECDIS and Inland ECDIS, enabling the navigator to see the position of the vessel, taking into account the wave height relative to the bottom in real time; 3. The methods of parallel bottom topography transferring rely only on the data of statistical observations using iterations. These methods usually work well on sandy and silty soils, where the relief has clear wave-like forms, as well as frequent external influences following the main general direction. Keywords: RIS, dynamic processes, "scale factor", "chart dynamic model", ECDIS.

Parameter Prediction of the Non-Linear Nomoto Model for Different Ship Loading Conditions Using Support Vector Regression

Significant changes in the load of cargo ships make it difficult to simulate and control their motion. In this work, a parameter prediction method for a ship maneuvering motion model is developed based on parameter identification and support vector regression (SVR). First, the effects of least-squares (LS) and multi-innovation least-squares (MILS) parameter identification methods for the non-linear Nomoto model are investigated. The MILS method is then used to identify the parameters of the non-linear Nomoto model under various load conditions, and model training datasets are established. On this basis, SVR is used to predict the parameters of the non-linear Nomoto model. The results reveal that the MILS method converges faster than the LS method. The SVR method achieves lower accuracy than the MILS method, but exhibits reasonable prediction accuracy for zigzag motions, and the maneuvering motion model can be predicted as navigation conditions change.

Longitudinal Control Strategy for Connected Electric Vehicle with Regenerative Braking in Eco-Approach and Departure

The development of more sustainable urban transportation is prompting the need for better energy management techniques. Connected electric vehicles can take advantage of environmental information regarding the status of traffic lights. In this context, eco-approach and departure methods have been proposed in the literature. Integrating these methods with regenerative braking allows for safe, power-efficient navigation through intersections and crossroad layouts. This paper proposes rule- and fuzzy inference system-based strategies for a coupled eco-approach and departure regenerative braking system. This analysis is carried out through a numerical simulator based on a three-degree-of-freedom connected electric vehicle model. The powertrain is represented by a realistic power loss map in motoring and regenerative quadrants. The simulations aim to compare both longitudinal navigation strategies by means of relevant metrics: power, efficiency, comfort, and usage duty cycle in motor and generator modes. Numerical results show that the vehicle is able to yield safe navigation while focusing on energy regeneration through different navigation conditions.

Effects of Climate Change on Navigability Indicators of the Lower Athabasca River, Canada

The lower Athabasca River (Canada) has experienced notable declines in streamflow and increasing oil sands development since the 1970s. This study investigates the potential impacts of climate change on navigability using both observed historical and projected future flows derived via hydrological simulations driven by an ensemble of statistically downscaled general circulation model climate data. Our use of proposed indices that form the Aboriginal Navigation Index (ANI) and a new index based on percentage over threshold (POT) occurrences yielded novel insights into anticipated changes to the flow regime. Comparisons of near (2041–2070) and far (2071–2100) future periods with the historical baseline (1981–2010) yielded results that project significant reductions in the 500 m3 s−1 POT during the fall navigability period spanning weeks 34 to 43, as well as reductions in the integrated ANIFall. These results indicate that challenging navigational conditions may become more frequent in the second half of the 21st century, not only during this fall period but also earlier into the summer, due to a shift in the flow regime, with potentially severe impacts on the users of the river channels. Our assessment approach is transferable to other regional study areas and should be considered in water management and environmental flow frameworks.

Peculiarities of joint influence of navigation intensification and climate change on fast ice distribution in the Ob’ Bay

All year–round navigation in the Ob’Bay has been operating for more than ten years. In recent years it has been performed most actively at three points: the port terminals Sabetta and «Utrenniy» (on the opposite coasts in the northern part of the bay) and the oil loading terminal «Vorota Arktiki» (in the southern part of the bay, off cape Kamenny). Regular winter navigation to Sabetta began in 2013 and to cape Kamenny in 2015. In recent years, the number of vessels in November–May has already risen to about 380 per season. The winter navigation in the fast ice is performed along ice channels, which should impact on the fast ice stability. The aim of this research was to determine the influence of navigation on the fast ice distribution in the Ob’Bay in terms of climate changes. To analyze navigation impact on the fast ice distribution in the Ob’Bay, data on air temperature, ice conditions and number of vessels in the winter period were used in the work. The sum of the freezing degree days (FDD) was chosen as a parameter of winter conditions severity. The mean location of the south boundary of the flaw polynya per season was a parameter of the fast ice stability. Such an approach reduced the influence of short–term fluctuations of temperature and ice conditions. The data analysis carried out over the last 25 years has confirmed a significant influence of navigation on the fast ice distribution. It has been found that for the range from mean to mild winter conditions (an estimate using FDD), the dislocation of the flaw polynya boundary in the south direction amounted to 0.4–0.8 degrees of latitude (25–50 miles) because of winter navigation intensification. Winter conditions more severe than mean have not been recorded in the region over recent years. Therefore, such estimates were not obtained for them. The discovered changes of ice conditions are significant for the region. The transfer from fast ice to drifting ice of different types, forms and concentration will lead to the corresponding restructuring of other natural processes (water dynamics, litho-dynamic regime, etc). Subsequently the impact of hydrometeorological factors on engineering facilities can change, affecting the navigation conditions, scenarios of loading on the hydraulic structures, absolute loading values, etc. This is a factor to consider in the economic development of the region.

Legal status of the intergovernmental organization of the Danube Commission in the conditions of technical progress of shipping

The article presents the legal status of the international intergovernmental organization of the Danube Commission. The Convention on the Regime of Navigation on the Danube in 1948 defined the institutional and legal structure of the DC, which is an integral feature of any international intergovernmental organization and is determined by its purpose, functions and tasks, which were set by the member states in the founding act of this organization. In its work, the DK relies on the rich historical experience of regulating shipping on international rivers in Europe. The priority areas of its activity are the unification of regulatory acts for navigation on the Danube, promotion of improvement of navigation conditions and improvement of shipping safety, creation of other conditions for the integration of the Danube into the European system as the main transport route. Ukraine is a full member of the international intergovernmental organization DC. The basis is the acquisition of membership in the international intergovernmental organization of the Danube Commission of Ukraine in accordance with the Decree of the Presidium of the Verkhovna Rada of the Ukrainian SSR dated February 18, 1949 "On the ratification of the Convention on the Danube Navigation Regime dated August 18, 1948. There are problems related to shipping and ecology, so it is necessary to clearly define the levels of certain regions and sections of the Danube River, namely the improvement of navigation conditions and improvement of navigation safety. Also, certain ecological restorative measures should be proposed in order to prevent the loss of ecological status. With the help of joint projects, opportunities for improving environmental and shipping conditions should be identified. The Danube Commission is designed to determine the prospects for more active development of trade and transportation on the Danube and the technical progress of shipping, the creation of other conditions for the integration of the Danube into the European system as the main transport route. Shipping is regulated by various international legal and national instruments, in particular, guaranteeing the safety of shipping. The updated version of the "Plan of the main works aimed at achieving the recommended dimensions of the navigation, hydraulic and other structures on the Danube River" and the issue of assisting the national administrations of waterways in carrying out annual hydraulic works were considered.

On the choice of a mathematical model for constructing the trajectory of the vessel in the decision support system by the boatmaster

The article shows that modeling the movement of ships allows you to build predictive trajectories of movement of both your own vessel and other vessels in the water area. The issues of modeling and software construction of the proposed dynamic trajectory of the vessel as part of the ship's decision support system in navigation (DSS) are considered. The analysis of mathematical models of vessel movement that have proven themselves positively in research and design practice is carried out. The adequacy of the mathematical model was assessed taking into account the definition of the limits of its applicability, i.e. identification of typical modes of movement and the design (type) of the vessel for which the selected model can be used. The analysis of theoretical calculations and oscillograms of full-scale tests of serial vessels is carried out, showing that the dynamics of river displacement vessels is characterized by a number of specific features. The method of choosing a mathematical model of ship movement in order to create a DSS when controlling movement at short distances in cramped navigation conditions is proposed.

Prediction of biological development effects on drag forces of ceramic hull coating using Reynolds-averaged Navier–Stokes-based solver

Ships in service feature surfaces that exhibit biofouling, which alters the hydrodynamics of the vessels, thus affecting their normal displacement and significantly increasing their fuel consumption. The application of three types of ceramic coatings as ecological, effective and durable alternatives to commercial silicone-based marine coatings is investigated in this study. Three different ceramic glazes and two control commercial paints are analysed in an actual environment during 20 months of exposure to simulate the navigation conditions such that growth and roughness data can be obtained and then applied to computational fluid dynamics (CFD) software using an open-source Reynolds-averaged Navier–Stokes solver. The CFD results are validated under smooth hull conditions with a full-scale Kriso Container Ship (KCS) model and with different levels of hull roughness. The developed approach shows that the drag in hulls coated with conventional paint is 19% greater than that in hulls with ceramic coating.

Development and Application of a New Auxiliary Diversion Structure for Mountain Ship Lock: A Case Study of Wuqiangxi Lock in China

Ship locks on mountain rivers usually experience difficulties owing to harsh flow conditions such as strong oblique flow and backflow, which significantly affect navigation safety and efficiency. To improve navigation conditions, a structural measure involving pile-foundation permeable dislocation-type diversion vanes, a new type of diversion structure, is proposed by analyzing the features and working mechanisms of the existing diversion structures. Based on a typical mountain ship lock—the Wuqiangxi Lock—model tests including various schemes were conducted to investigate the effects of the new diversion structure. The new diversion structure obtained better results than other existing diversion structures, particularly in terms of reducing the transverse flow velocity extremums. By controlling the diversion volume, stabilizing the deflection angle, and dissipating the flow energy, the new diversion structure could effectively weaken the oblique flow intensity at the entrance area. In addition, comparisons of its cost efficiency with that of a hybrid measure combining riverbed dredging and diversion piers was carried out. Moreover, its performance of practical application in the reconstruction project of the Wuqiangxi Lock was demonstrated. Based on the investigation presented herein, the new diversion structure is a promising approach for improving flow conditions at the entrance area of the lock approach.

Тhe structure of morbidity of fishermen working in different geographical regions

INTRODUCTION: The existing multiple factors of the ship’s environment, together with the climatic conditions of navigation, have a long and complex effect on the body of seamen. As a result, they often cause significant changes in the body. In turn, such changes can cause the emergence and development of many diseases.OBJECTIVE: To analyze the morbidity of trawl fleet fishermen working in different climatic regions, possible factors contributing to the occurrence of diseases, to develop recommendations for reducing diseases with disability of workers.MATERIALS AND METHODS: The morbidity of fishermen of the Arkhangelsk trawl fleet for the same period when working in the fishery in different climatogeographic regions was studied. 464 people of 4 crews of large freezing fishing trawlers aged 25–49 years (average age 41.8±9.5 years) and work experience from 3 to 10 years were under monitoring. The fishing area is the Norwegian Sea (northern climate zone, crew 237 people) and the Moorish Economic Zone (southern region, crew 217 people). The duration of the works ranged from 168 to 185 days. 10 voyage reports from on-board logbooks (5 times in each of the climatic regions) were used as sources of information on morbidity. Statistics: The McNemar criterion was used for comparative analysis between frequency indicators, and the MannWhitney criterion was used for absolute averages. The statistical significance level p<0.05 was regarded as proven statistically significant differences between the compared indicators.RESULTS: The morbidity of seafarers, according to the initial appeals, had statistically significant differences when working in different climatogeographic regions. The frequency of cases of temporary disability for people working in tropical regions turned out to be much higher in comparison with the northern ones. At the same time, the average duration of the disease in the absolute majority of nosological forms (except for skin and subcutaneous tissue diseases) had no statistically significant differences between the groups of sailors.DISCUSSION: Territorial features of fishing produce the characteristic of morbidity. Among them, the greatest contribution to the occurrence of diseases are frequent international contacts, peculiarities of processing of harvested fish, tension of adaptation mechanisms due to work in unusual conditions combined with hard work. The identified causes of morbidity among trawl fleet fishermen require the development of special measures to level them, prevent the development of chronic diseases.CONCLUSION: Is made about the need for constant monitoring of seafarers to determine adaptive changes during the voyage period and during the readaptation of the crew to coastal conditions. Within the framework of the medical support system for water transport workers, it is necessary to take into account the adverse factors of the professional environment in order to create high-quality and safe working conditions.

Analysis and Prediction of Poyang Lake’s Navigable Conditions under a New Hydrological Regime

Human activities have profoundly changed the hydrological regime and trends of rivers and lakes, which, in turn, has affected the utilization of their navigable conditions. However, few studies have focused on the effects of changes in hydrological regimes and trends of rivers and lakes on navigable conditions. Thus, this study intensively analyzes and investigates the navigable depth at the major control sections in the lake area during the dry season in the period before 2002, when the Three Gorges Reservoir was not yet constructed, and the period from 2003 to 2019, when the Three Gorges Project was put into operation with impoundment based on the dry-season water level curve in the Poyang Lake area since the operation of the Three Gorges Reservoir. This study also further analyzes the influence of the change in the hydrological regime on the navigable depth in the lake area. The results show that the waterway depth and width could meet the navigation requirements before 2002. From 2003 to 2019, whereas the water level with a 98% guarantee rate of duration at the Xingzi Hydrometric Station decreased, that at the Hukou Hydrometric Station increased. The waterway depth and width at both the Hukou and Xingzi hydrometric stations could meet the requirements of the size of Grade II waterways. This study also performs a simulation prediction of the water regime of Poyang Lake under a new hydrological regime using the mathematical model of water and sediment of the Changjiang River Scientific Research Institute. The results reveal that in 2030 and 2050, after the Three Gorges Reservoir has been in operation for 30–50 years, the water levels at the Hukou, Xingzi, and Wucheng hydrometric stations (Hukou) of Poyang Lake will decline by approximately 0.18–0.66 and 0.10–0.24 m, respectively. Although the overall navigable depth can basically meet the navigation requirements for a period of time, the trend of the long-term declining water level may cause unsafe navigation risks.

A Testing Method for Shipborne Atomic Gravimeter Based on the Modulated Coriolis Effect

Shipborne atomic gravimeter (SAG) is an instrument that can directly measure absolute gravity in dynamic environments. As a new type of gravity sensor, a standard method for evaluating its detailed performance has not been proposed and the detailed performance of SAG was rarely reported. In this paper, a system of dynamic gravity measurement, which was integrated with a home-made atomic gravimeter, is demonstrated, and a novel and simple method for testing the performance of SAG on the lake based on the modulated Coriolis effect is put forward. Firstly, in the state of ship mooring, a tilt modulation of the gravity sensor has been realized to make sure the Raman wave vector is parallel to the gravity axis. Moreover, a comparison between the measurement result of CG-5 and SAG has also been carried out to evaluate the accuracy of the SAG. Then, the Coriolis effect modulating experiment is carried out with various routes on lake to test its performance in dynamic environments. In the ship mooring state, the accuracy has been demonstrated to be 0.643 mGal. The internal consistency reliabilities are evaluated to be 0.8 mGal and 1.2 mGal under the conditions of straight line and circle navigation, respectively.

Solution Options for Problems of Navigation on a Limited Section of the Volga River from Gorodetsky Hydroelectric Complex to Nizhny Novgorod, Including Taking Into Account the Assessment of the Impact on the Sanitary-Epidemiological and Environmental Situation in the Region

The paper proposes a variant of choosing the optimal solution to the large-scale scientific, technical and ecological-economic problem of the European part of the Russian Federation based on the integrated use of results of numerical modeling of hydrodynamic processes, expert environmental assessments and rating economic comparison.The object of scientific research is the section of the Volga River from the Gorodetsky hydroelectric complex to Nizhny Novgorod (from 852.5 to 899 km along the ship’s course). The purpose of the work is to prepare proposals for the choice of an option for improving navigation conditions on the Volga River section under consideration in the lower reaches of the Gorodetsky locks under various flow regimes through the Gorodetsky hydroelectric complex, taking into account the priorities of environmental protection, protection of water bodies and use of water resources established by legislation. As a result of the work, a variant of the project proposed for implementation on the territory of the Nizhny Novgorod region for the rational solution of navigation problems on the Volga River, taking into account the assessment of the impact on the sanitary-epidemiological and environmental situation in the region, flooding and flooding zones. The project includes the construction of a third parallel lock in the area of Gorodetsky locks No. 15–16 and the creation of a navigable slot with a guaranteed fairway depth of 4.0 m.

Paths Across the Sea: Meteo-Marine Conditions for Coastal Navigation Around the Balearic Islands During the Middle and Late Bronze Ages

Throughout history the Balearic Islands have had different degrees of social connectivity between the islands themselves and between them and the mainland. While the influence of historical dynamics is well documented, less so is the impact of winds, currents, and meteo-marine conditions. This paper analyses the meteo-marine conditions for coastal navigation to better understand how these configured the main maritime routes across the islands. We focus on the seafaring communities of the Balearic Islands in the Bronze Age when a series of sites along the coastline suggest the creation of a network of coastal infrastructure to support maritime mobility.

Climatic changes in the calculated levels of port hydraulic structures for the Indiga Port area

The development of the mineral resource base of the Arctic region of the Russian Federation has become possible, among other things, due to the increase in the duration of the navigation period and the improvement of navigation conditions due to climatic changes. The development of oil and gas reserves in this region creates the need to provide marine transport infrastructure, and, consequently, the development of existing and construction of new port hydraulic structures. The author of the article reviewed the data of satellite observations of the sea level anomaly in the area of the construction of the Indiga port in the southeastern part of the Barents Sea from October 1992 to September 2022. It is shown that there is a stable positive trend towards sea level increasing over a period of 30 years, which indicates that a number of data series used in constructing probability curves according to regulatory methods are nonstationary. The lack of consideration of climatic changes in the level regime leads to incorrect results of calculations of water levels of a given probability according to current regulatory methods, therefore, the article deals with an example of considering the data of climatic modeling of the level regime of the Indiga port area for the life cycle of port hydraulic structures. Dividing the service life of the structure into stages, which consider the change in the marks of the structure or its absence, depending on the actually observed increase in the level of the water area, will ensure the reliability and safety of operation throughout the life cycle. The reserves laid down during the design and the creation of long-term reconstruction plans will make it possible to carry out work on raising the berth marks for berthing structures and the marks of the upper structure of protecting structures with the least expenditure of material resources and time.

Potential Use of Mangroves as Nature-Based Solutions to Improve Navigation Conditions in a Port in Southern Brazil

Potential Use of Mangroves as Nature-Based Solutions to Improve Navigation Conditions in a Port in Southern Brazil

Bovine Arch Variation Detected During Cerebral Digital Subtraction Angiography in Nepalese Population: A Retrospective Study

Background:Anatomical variation of aortic arch play’s significant role in diagnosing and planning further therapeutic intervention of cerebrovascular diseases. Objectives: Aim of this study was to review the neck vessels arising from the aorta and to determine the prevalence of aortic arch variation in digital subtraction angiography. Materials and methods: after ethical clearance from institutional review board, study was conducted retrospectively in 129 patients who underwent digital subtraction angiography for various reasons from December 2020 to December 2021. Age ranged between 21-87 years old. 88 were males and 41 were females. Mean age was 57.89. Results: bovine arch variations were found in 2.3% in our study population. Classic branching pattern was demonstrated in 97 % of studied cases. Conclusion: Determining bovine arch variation though rarely detected, is essential for diagnostic and therapeutic intervention of cerebrovascular conditions for uncomplicated navigation of catheters and guide wires.

Assessment of ship manoeuvring safety in waterway systems by relative navigational risk

The safety of vessels navigating in the sea waterway system is ensured by fulfilling the acceptable restrictions called safe ship operation conditions in that system. The assessment of navigation safety is particularly important when the conditions for safe operation of ships in the waterway system are changed concerns increasing the maximum parameters of vessels, increasing the allowable hydrometeorological conditions or changing the minimum tug assistance. The article presents a method for assessing navigation safety when the conditions for the safe operation of vessels in the waterway system get changed. The method uses two indicators, which are difference in navigation risks and relative navigation risk. To determine the navigational risk, algorithms were developed for calculating the probability of accidents caused by the deterioration of navigation conditions and technical failure of ship equipment and tugs. Another algorithm was developed for calculating the consequences of the accidents that involve blocking a waterway by a ship anchoring in an emergency, grounding, impact of the ship against a port structure or moored ship and a collision with another ship in motion. The method developed for assessing navigation safety by means of relative navigation risk can be used in practice when changing the conditions for safe operation of vessels in the waterway system and when the system is modernized. Navigational safety management is a decision process that is implemented in the loop presented in the article. The acceptable risk is determined on the basis of vessel traffic intensity and ship parameters defined by safe operation conditions for a given waterway system. Relative navigational risk may be used in assessment and comparison of various conditions of safe ship operation. The probability of an accident caused by ship's moving outside the available navigable area due to technical failures of ship equipment or tugs is determined, depending on the type of port waterway and the manoeuvres performed.

Characteristic Analysis of Navigable Flow Conditions and Numerical Simulation of Water Conservancy in Steep Bay Section of the Navigable Tunnel

Compared with traditional low-standard ship locks, large-section navigable tunnels have the advantages of increasing water resources dispatching, increasing ship crossing channels and shipping. It is necessary to explore the characteristics of navigable flow conditions under the condition of navigable tunnel and study effective measures to improve the navigable flow conditions at the entrance of approach channel of navigable tunnel in steep bay section. However, the existing research results neglect the navigation channel layout in the steep bay section, and it’s lack of theoretical research on improving the flow conditions at the entrance of approach channel of navigable tunnel in the steep bay section. For this, this article studies the characteristics of navigation flow conditions and numerical simulation of water conservancy in steep bay section of the tunnel. Firstly, the physical model of tunnel navigation in steep bay section is designed to ensure the geometric similarity, flow movement similarity and dynamic similarity between the model and the actual situation in steep bay section. Then, the numerical simulation of navigation water conservancy in steep bay section of tunnel is carried out, and the continuity equation and momentum equation in the new coordinate system are given. This article explores the navigation scheme of large cross-section navigable tunnel in order to obtain effective measures to improve the navigation conditions of this section. Finally, the corresponding experimental results and analysis are given.