Practical Navigation Research Articles

Using visual scene memory accuracy as a predictor of spatial navigation performance

AbstractSpatial navigation is a fundamental cognitive function essential for daily life. Navigation skill assessment predominantly relies on self‐reports, with varying accounts regarding their validity. The current study aimed to determine whether performance on an objective visual scene memory recognition ability task could serve as a valid predictor of wayfinding navigation performance. A standardized sense of direction scale was used to compare the predictiveness of self‐report with the visual recognition test for objective navigation performance. Results from multiple regression analyses indicated that better performance on the visual, but not the verbal memory task significantly predicted wayfinding ability. Visual memory performance was also a better predictor of navigation performance than participants' self‐reported sense of direction. This study therefore suggests that the assessment of visual scene memory is a promising and ecologically valid way to predict everyday practical navigation ability—in addition to or instead of via the use of self‐reports.

The Utility of Augmented Reality in Spinal Decompression Surgery Using CT/MRI Fusion Image.

In spine surgery, instrumentation surgery using augmented reality (AR) and navigation systems have become widespread, while decompression surgery using those applications is not so common. However, we sometimes encounter intraoperative problems such as excessive blood loss or bony resection in decompression surgery. Therefore, a practical navigation system is needed for safer spinal decompression surgery. Furthermore, the cost of AR and navigation systems has been expensive. In this study, we report the utility of applying the AR system of the head-mounted display (HMD) at a lower cost to identify the osteotomy area of laminectomy for spinal decompression surgery.3D CT/MRI fusion images are created preoperatively to generate 3D data consisting of the nerve elements, a dural tube and nerve roots, and the bony elements of the spine. Then, we made the 3D data of the bone after decompression by 3D editing free software. Uploading the created 3D data of both 3D CT/MRI fusion and preoperative planned laminectomy images to the AR software in the HMD, we could confirm the proper decompression area with the 3D images projected through the HMD. This system was useful for cervical and lumbar decompression for confirming the proper decompression area preoperatively.We could perform decompression surgery just designed with this system. This system is a preoperative planning system that allows 3D HMD visualization to keep track of surgical orientation. It does not allow preoperative verification so far. However, this system has various possible applications and is considered a promising system for the future.

Ultra-Wideband Positioning Sensor with Application to an Autonomous Ultraviolet-C Disinfection Vehicle.

Due to the COVID-19 virus being highly transmittable, frequently cleaning and disinfecting facilities is common guidance in public places. However, the more often the environment is cleaned, the higher the risk of cleaning staff getting infected. Therefore, strong demand for sanitizing areas in automatic modes is undoubtedly expected. In this paper, an autonomous disinfection vehicle with an Ultraviolet-C (UVC) lamp is designed and implemented using an ultra-wideband (UWB) positioning sensor. The UVC dose for 90% inactivation of the reproductive ability of COVID-19 is 41.7 J/m2, which a 40 W UVC lamp can achieve within a 1.6 m distance for an exposure time of 30 s. With this UVC lamp, the disinfection vehicle can effectively sterilize in various scenarios. In addition, the high-accuracy UWB positioning system, with the time difference of arrival (TDOA) algorithm, is also studied for autonomous vehicle navigation in indoor environments. The number of UWB tags that use a synchronization protocol between UWB anchors can be unlimited. Moreover, this proposed Gradient Descent (GD), which uses Taylor method, is a high-efficient algorithm for finding the optimal position for real-time computation due to its low error and short calculating time. The generalized traversal path planning procedure, with the edge searching method, is presented to improve the efficiency of autonomous navigation. The average error of the practical navigation demonstrated in the meeting room is 0.10 m. The scalability of the designed system to different application scenarios is also discussed and experimentally demonstrated. Hence, the usefulness of the proposed UWB sensor applied to UVC disinfection vehicles to prevent COVID-19 infection is verified by employing it to sterilize indoor environments without human operation.

Co-governance, Transregional Maritime Conventions, and Indigenous Customary Practices Among Subsistence Fishermen in Ende, Indonesia

This article presents a case study of a fishery in the port-town community of Ende, Flores, a former littoral hub located at the periphery of major commercial systems in the Indo-Pacific region. The article argues that more attention be paid to the role of transregional maritime networks, nautical conventions, and navigational practices embedded within local tenure systems to understand the apparent absence of formal control of marine and coastal resources. Through ethnographic and archival research, this study identifies the presence of indigenous institutions for fishing grounds regulation and documents the existence of broader transregional norms dictating proper fishing and navigation. Exploring the interactions between more pluralistic customary systems that exist in port-towns such as Ende and recent fishery development policies, the article discusses some of the obstacles to implementing sustainable co-management strategies. While the Indonesian central government is strongly promoting co-governance approaches for resource management, these institutional models are based on geographically narrow definitions of tradition and customary law which can lead to management failures, such as elite capture and local fishers’ disenfranchisement. In this case, policies emphasize the formation of cooperative groups without considering transregional beliefs about independence and pre-established systems of obligations. As a result, disputes among the fishermen, conflicts with local fishery officers, and the use of non-sustainable practices continue. For example, embodying predominant Southeast Asian beliefs, Endenese are known for their entrepreneurial nature and strong self-sufficiency ethos. Yet, these notions are ignored by local government agencies that view the fishermen as selfish and disorganized. In order to formulate true participatory solutions, a careful assessment of the role played by transregional perspectives that go beyond geographically localized understandings of customary practices is needed. The article concludes with a consideration of the role played by decentralization processes, subsidies, and aid programs in entrenching poverty and inequality among local communities.

Data mining approach for automatic ship-route design for coastal seas using AIS trajectory clustering analysis

In this paper, we propose an automatic route design method based on simple recurrent unit (SRU) and automatic identification system (AIS) data. Laplacian eigen maps and Gaussian kernel functions are used to compress the AIS data and extract the turning points of all ships. Fuzzy adaptive density-based spatial clustering of applications with noise (FA-DBSCAN) technique is used to cluster the turning points obtained at the preprocessing stage to obtain the turning region. Optimal turn region matching is used to connect the turning regions of similar routes, and the SRU neural network algorithm is used to learn the relationship between different types, sizes, and drafts of ships in each turning region; extract the feature-turning points; and obtain the recommended coastal routes, speed, and course of each type of ship. In the experimental stage, a large variety of AIS data from two sea areas are used to compare and analyze the designed route and real-ship data through LSTM and SRU experiments. The results show that the SRU algorithm improves the training speed and accuracy in comparison to LSTM, while the generated automatic route meets the requirements of navigation practice.

Social-material aspect of navigation technology: using structural topic models to identify the causes of ship accidents (1973–2018)

AbstractWhat are the major factors contributing to ship accidents, and how do these factors evolve in the long term? This study addresses these two questions by leveraging an unsupervised machine learning method named structural topic modelling to identify the causes of ship accidents. The study analysed 2,341 task errors manually collected from 441 reports issued by four government agencies covering a 45-year time span. The results show that the structure of causes of ship accidents remained essentially the same during this period. This highlights the social-material aspect of navigation technology, indicating that the use of advanced technology may not necessarily lead to safer navigation practices, and the interaction between the technology and human agency must be focused on in the bridge management context. Additionally, the computer-assisted textual data analysis highlights pilot-related factors, which might be rooted in the unsupervised and difficult-to-verify handover procedures between pilots and captains, thereby underlining the importance of appropriate piloting regulations.

Path Planning for Autonomous Ships: A Hybrid Approach Based on Improved APF and Modified VO Methods

In this research, a hybrid approach for path planning of autonomous ships that generates both global and local paths, respectively, is proposed. The global path is obtained via an improved artificial potential field (APF) method, which makes up for the shortcoming that the typical APF method easily falls into a local minimum. A modified velocity obstacle (VO) method that incorporates the closest point of approach (CPA) model and the International Regulations for Preventing Collisions at Sea (COLREGS), based on the typical VO method, can be used to get the local path. The contribution of this research is two-fold: (1) improvement of the typical APF and VO methods, making up for previous shortcomings, and integrated COLREGS rules and good seamanship, making the paths obtained more in line with navigation practice; (2) the research included global and local path planning, considering both the safety and maneuverability of the ship in the process of avoiding collision, and studied the whole process of avoiding collision in a relatively entirely way. A case study was then conducted to test the proposed approach in different situations. The results indicate that the proposed approach can find both global and local paths to avoid the target ship.

CUSTOMS FORMALITIES FOR FOREIGN WARSHIPS, THEIR ARMS AND CREWS IN THE UKRAINIAN PORTS

The article is devoted to determining the current state and ways to improve the legal regulation of customs formalities for foreign warships, their arms and crews in the Ukrainian ports. The relevance of the research topic is due to the need to find the optimal model of legal regulation for such activities in Ukraine as the state port and the fragmentation of current legal research in the field of custom port formalities. The purpose of the article is to define the current state of organizational and legal regulation for the implementation of customs formalities for foreign warships, their arms and crews in the Ukrainian seaports, outlining possible ways to update and improve it. The methodological basis of the research is formed by general scientific and special legal methods of scientific knowledge (dialectical, analysis and synthesis, scientific abstraction, forecasting). The task of the article is to develop proposals for improving the legal regulation of customs formalities applicable to foreign warships in the Ukrainian ports. The article characterizes and analyzes the provisions of law, regulations and local acts in force in the Ukrainian seaports. It is noted that the current legislation of Ukraine, according to the established practice of navigation and customary norms embodied in international treaties, defines a special procedure for customs formalities in respect of foreign warships, their arms and crews. The characteristic feature of such legislation is that almost identical rules on such formalities are placed in different normative acts of different legal force. This specifies the necessity to develop a universal normative document that would define all aspects of entry, stay and leaving the inland waters for foreign warships, in particular to the waters of the Ukrainian seaports.

Kanne Lobal: A conceptual framework relating education and leadership partnerships in the Marshall Islands

Kanne Lobal: A conceptual framework relating education and leadership partnerships in the Marshall Islands

An application-orientated anti-collision path planning algorithm for unmanned surface vehicles

This article presents a reasonable anti-collision path planning algorithm with the properties of strong practicability and high degree of automation for unmanned surface vehicles (USV) or Marine Autonomous Surface Ships (MASS) in dynamic environment situation. Based on the requirements of the International Regulations for Preventing Collisions at Sea (COLREGs), the qualitative provision about the apparent intention of anti-collision maneuver is quantified in the algorithm. Meanwhile, the Boolean expression technology is adopted to help determine the type of encounter situation and action manner automatically, which provides theoretical basis for the application of path-planning algorithm. In addition, the modified velocity obstacle approach and artificial potential fields are combined to improve the practicality and rationality of the optimization solution. Finally, simulation examples consisting different traffic scenarios are discussed to demonstrate the effectiveness and practicality of the proposed scheme. •In this article, the apparent and substantial action is quantified by the parameter relative heading angle rather than heading angle, which is closer to navigation practice. •The Boolean expression is adopted to realize the automatic logical identification of encounter type and action manner, which makes the anti-collision decision scheme more complete. •The concepts of safety course region and feasible course region in VO approach are proposed to help determine the alteration angle for modified APF algorithm. •The concept of presupposed number of steps is proposed to eliminate the course vibration for the optimization results based APF algorithm, which could greatly improve the practicality of the proposed scheme.

Autonomous Collision Avoidance of Unmanned Surface Vehicles Based on Improved A Star And Minimum Course Alteration Algorithms

The ability to avoid shorelines, reefs and moving ships or obstacles is the premise of automatic navigation. For achieving the goal, conventional A star algorithm is improved to plan route globally. The safety distance is set between planning route and obstacles. Additionally, the planning route is further optimized to remove unnecessary waypoints, and only vital waypoints are retained for conforming to navigation practice and track keeping control. Besides, minimum course alteration algorithm (MCA) is proposed to avoid moving ships or obstacles constrained by COLREGs. The proposed algorithms are validated in simulation. The results show that the algorithms are credible in two and multi ships encounter situations, even the targets ships take unexpected course alteration and the own ship could well avoid collision with shorelines, reefs and moving ships or obstacles under external disturbance.

Legal Regulation of Merchant Shipping (Review of the textbook “The Law of the Sea and International Maritime Business”)

The law of the sea is central to the modern international system and has a significant impact on the global economy. Its study is undoubtedly necessary for the education of highly qualified lawyers in the field of international law due to the fact that the safety of sea transport corridors plays a significant role in the development of international trade relations. Freedom of navigation practice in the post-industrial economy depends on the quality of the institutions of public maritime law and the efficiency of the execution of maritime contracts. Authors of the textbook made efforts to master the provisions of public maritime law in their relationship with the practices of merchant shipping, which is certainly interesting and useful due to the importance of maritime trade for achieving the sustainable development goals.

He kaiwhakatere ahau: A (k)new practice model in the care of rangatahi and whānau

INTRODUCTION: A Kaiwhakatere position funded as part of Te Taitimu Trust’s Ngā Moko Ā Ngā Tūpuna initiative has created a space for a navigation practice model within the context of suicide prevention. The Kaiwhakatere is akin to a “professional auntie” who draws on her knowledge of whakapapa, whenua and whānau to engage rangatahi and whānau and build their connectedness and confidence as Māori.METHOD: Discussions with the Kaiwhakatere (Georgina) and the Chief Executive (Zack) of the Trust have explored the emergence of the Kaiwhakatere practice model. This model draws on Georgina’s social work expertise and her recollections of her own upbringing.IMPLICATIONS: The resulting Taikoko (rising spring tide) practice model of the Kaiwhakatere is grounded in Tākitimutanga to ensure that rangatahi and their whānau are connected to their cultural heritage, to their environment, and to a network of supports and relationships that facilitate their collective resiliency. Early feedback from rangatahi, whānau and education providers has been positive and encouraging.

Comparison between the collision avoidance decision-making in theoretical research and navigation practices

Collison between ships is one of the major contributors to maritime accidents. To reduce ship collision accidents, the research on collision avoidance decision-making has been drawing much attention from various parties. In this research, extensive literature and expert knowledge are collected and analyzed to identify the common sense and discrepancies between collision avoidance decision-making for theoretical research and navigation practices. The key factors that are considered in the two perspectives are identified and discussed, based on which, the knowledge structures that can represent the development of the process in the two perspectives are established. A series of comparisons between the knowledge structure based on theoretical research and navigation practices are conducted. The comparisons indicate clear common sense and discrepancies between the theoretical research and navigation practices regarding collision avoidance decision-making. The potential causes of them are also analyzed. The research results would be beneficial for the development of collision avoidance decision-making for both autonomous and conventional manned ships in maritime traffic.

Collision-avoidance path planning for multi-ship encounters considering ship manoeuvrability and COLREGs

Abstract Ship collision prevention has always been a hot topic of research for navigation safety. Recently, autonomous ships have gained much attention as a means of solving collision problems by machine control with a collision-avoidance algorithm. An important question is how to determine optimal path planning for autonomous ships. This paper proposes a path-planning method of collision avoidance for multi-ship encounters that is easy to realize for autonomous ships. The ship course-control system uses fuzzy adaptive proportion-integral-derivative (PID) control to achieve real-time control of the system. The automatic course-altering process of the ship is predicted by combining the ship-motion model and PID controller. According to the COLREGs, ships should take different actions in different encounter situations. Therefore, a scene-identification model is established to identify these situations. To avoid all the TSs, the applicable course-altering range of the OS is obtained by using the improved velocity obstacle model. The optimal path of collision avoidance can be determined from an applicable course-altering range combined with a scene-identification model. Then, the path planning of collision avoidance is realized in the multi-ship environment, and the simulation results show a good effect. The method conforms to navigation practice and provides an effective method for the study of collision avoidance.

The Impact of Electronic Health Record-Based Simulation During Intern Boot Camp: Interventional Study.

BackgroundAccurate data retrieval is an essential part of patient care in the intensive care unit (ICU). The electronic health record (EHR) is the primary method for data storage and data review. We previously reported that residents participating in EHR-based simulations have varied and nonstandard approaches to finding data in the ICU, with subsequent errors in recognizing patient safety issues. We hypothesized that a novel EHR simulation-based training exercise would decrease EHR use variability among intervention interns, irrespective of prior EHR experience.ObjectiveThis study aims to understand the impact of a novel, short, high-fidelity, simulation-based EHR learning activity on the intern data gathering workflow and satisfaction.MethodsA total of 72 internal medicine interns across the 2018 and 2019 academic years underwent a dedicated EHR training session as part of a week-long boot camp early in their training. We collected data on previous EHR and ICU experience for all subjects. Training consisted of 1 hour of guided review of a high-fidelity, simulated ICU patient chart focusing on best navigation practices for data retrieval. Specifically, the activity focused on using high- and low-yield data visualization screens determined by expert consensus. The intervention group interns then had 20 minutes to review a new simulated patient chart before the group review. EHR screen navigation was captured using screen recording software and compared with data from existing ICU residents performing the same task on the same medical charts (N=62). Learners were surveyed immediately and 6 months after the activity to assess satisfaction and preferred EHR screen use.ResultsParticipants found the activity useful and enjoyable immediately and after 6 months. Intervention interns used more individual screens than reference residents (18 vs 20; P=.008), but the total number of screens used was the same (35 vs 38; P=.30). Significantly more intervention interns used the 10 most common screens (73% vs 45%; P=.001). Intervention interns used high-yield screens more often and low-yield screens less often than the reference residents, which are persistent on self-report 6 months later.ConclusionsA short, high-fidelity, simulation-based learning activity focused on provider-specific data gathering was found to be enjoyable and to modify navigation patterns persistently. This suggests that workflow-specific simulation-based EHR training throughout training is of educational benefit to residents.

Die Welt im Meer

Abstract Using the example of four maps, this essay discusses how the cartography of the oceans enabled perceptions of the earth as a whole and as a continuous realm of possibilities during the nineteenth century. Nautical charts, produced for practical navigation and committed to the precision ethics of physical geography, facilitated the participation of ports such as Bremen in overseas trade. Ocean maps, aiming at providing an overview and filling sea areas with scientific, political, or travel-related information, visualized thinking in global contexts and positioned marine and terrestrial spaces in new relations. Finally, maps of island colonies show the problems that accompanied the overseas communication of knowledge and how cartographers, by overwriting uncertainties, also inscribed ignorance into maps. All in all, from the perspective of the cartography of the oceans, a specific globality emerges that can be regarded as a distinctive cartographic reality.

An Outline of Multi-Sensor Fusion Methods for Mobile Agents Indoor Navigation

Indoor autonomous navigation refers to the perception and exploration abilities of mobile agents in unknown indoor environments with the help of various sensors. It is the basic and one of the most important functions of mobile agents. In spite of the high performance of the single-sensor navigation method, multi-sensor fusion methods still potentially improve the perception and navigation abilities of mobile agents. This work summarizes the multi-sensor fusion methods for mobile agents’ navigation by: (1) analyzing and comparing the advantages and disadvantages of a single sensor in the task of navigation; (2) introducing the mainstream technologies of multi-sensor fusion methods, including various combinations of sensors and several widely recognized multi-modal sensor datasets. Finally, we discuss the possible technique trends of multi-sensor fusion methods, especially its technique challenges in practical navigation environments.

Concise robust fuzzy nonlinear feedback track keeping control for ships using multi-technique improved LOS guidance

In order to solve the problem that the parameterized LOS (line-of-sight) guidance cannot be directly applied to the navigation practice, this paper proposed an indirect nonlinear feedback concise robust track-keeping control strategy for ships, which consists of a robust course-keeping controller and a MILOS (multi-technique improved LOS) guidance system. The second-order closed-loop gain shaping algorithm was employed to design the linear course-keeping controller, then the fuzzy logic system was used to adjust the integral coefficient online to improve the transient performance. The introduction of nonlinear feedback technique further reduces the steering frequency and saves energy. For the guidance system, three techniques are introduced to enhance the track-keeping effect. A nonlinear sideslip angle observer is developed to eliminate the static track error caused by the wind and current interference. A time-varying lookahead distance and a new advance turning distance are proposed to achieve the smooth turning between track sections. Simulation results show that compared with the conventional LOS guidance, the proposed strategy is more consistent with the requirement of navigation practice and has comprehensive advantages in both dynamic and static performance, which is of great significance for enhancing the ability of ship's autonomous navigation.

Implementation of drama therapy services in the North American school system: Responses from the field

AbstractDrama therapy is an emerging mental health practice in North American schools. Yet little research has focused directly on the role of drama therapists in schools or their service navigation practices and challenges. From February to July of 2018, drama therapists affiliated with the North American Drama Therapy Association currently working in North American schools were invited to participate in an online Qualtrics survey. A qualitative thematic analysis was conducted on open‐ended response items, the results of which reflect drama therapists' experiences pioneering direct and indirect services and responding to implementation challenges. Findings suggest that while drama therapists provide a number of critical school services, there are identifiable barriers to full integration into the system. Implications for drama therapists include the need for a further specified and structured role, formalized inclusion in student support teams, consistent opportunities to support both students and staff, more secure funding sources, clear implementation logistics, and increased awareness and education about drama therapy among school administrators, faculty, and mental health support staff.